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  • 51.
    Gupta, G. S.
    et al.
    Karolinska Inst, Inst Environm Med, Div Mol Toxicol, Stockholm, Sweden..
    Gliga, A.
    Karolinska Inst, Inst Environm Med, Div Mol Toxicol, Stockholm, Sweden..
    Hedberg, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Serra, A.
    Univ Tampere, Inst Biosci & Med Technol, Tampere, Finland.;Univ Helsinki, Inst Biotechnol, Helsinki, Finland..
    Greco, D.
    Univ Tampere, Inst Biosci & Med Technol, Tampere, Finland.;Univ Helsinki, Inst Biotechnol, Helsinki, Finland..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Fadeel, B.
    Karolinska Inst, Inst Environm Med, Div Mol Toxicol, Stockholm, Sweden..
    Cobalt-impregnated tungsten nanoparticles and cobalt ions trigger toxicity in differentiating neuronal cells: potential link to parkinsonian neurodegeneration2019In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 314, p. S201-S202Article in journal (Other academic)
  • 52. Gustafsson, J
    Bäckström, J
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Mohammed HabiburRahman, S
    Lindbergh, G
    Eriksson, S
    Cornell, A
    In-Situ Activated Hydrogen Evolution by molybdate addition to neutral and alkaline electrolytes2012In: Journal of Electrochemical Science and Engineering, ISSN 1847-9286Article in journal (Refereed)
  • 53. Hagman, H.
    et al.
    Boström, D.
    Lundberg, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Backman, R.
    Alloy degradation in a co-firing biomass CFB vortex finder application at 880 °C2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 150, p. 136-150Article in journal (Refereed)
    Abstract [en]

    Mechanisms of alloy degradation in a fireside N-S-O-C-H-Cl-Na-K atmosphere at 880 °C were elucidated using SEM-EDS, chemical equilibrium calculations, and XRD. Alloys 310S, 800H/HT, and 600 were studied after 0, 8000, and 16,000 h exposure in a boiler co-firing biomass waste. For 310S and 800H/HT it was shown that nitrogen formed internal Cr nitrides lowering the Cr activity and inhibiting internal alloy Cr permeation, and that NaCl and Na 2 SO 4 reacted with Cr oxide to form chromate and to accelerate the S and the Cl pickup. Alloy 600 showed no nitride or major chromate formation.

  • 54. Hagman, H.
    et al.
    Lundberg, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Boström, D.
    Alloy Selection for a Cofired Circulating Fluidized Bed Boiler Vortex Finder Application at 880 °c in a Complex Mixed Mode Corrosion Environment2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 11, p. 12857-12866Article in journal (Refereed)
    Abstract [en]

    X-ray diffraction and scanning electron microscopy (SEM) were used on a corroded industrial-scale circulating fluidized bed (CFB) boiler vortex finder (VF) 253MA alloy plate material to identify the dominating corrosion products and to enable a qualified selection of candidate alloys for the long-term, full-scale exposure study. Alloys 253MA, 310S, 800H/HT, Alloy DS, and Alloy 600 were chosen, and the alloy plates were exposed to the CFB boiler combustion atmosphere having an average temperature of approximately 880 °C, consisting of a moist globally oxidizing gas, burning hydrocarbons, CO2, CO, SO2, HCl, NH3, N2, alkali species, and erosive particles. The exposure times used in this study were 1750, 8000, 12000, and 16000 operating hours. After exposure, the alloy samples were cut, and cross-sections were dry-polished and analyzed with an SEM-backscatter electron detector (BSD) setup to quantify material loss and penetration depth of the corrosion attack. This work suggests two novel concepts: heavily affected depth (HAD) enabling quantitative evaluation of heavily degraded alloys and remaining serviceable metal thickness (RSMT) enabling the use of long-term corrosion data from one alloy to make rough service life estimations of other alloys exposed for significantly shorter periods. The findings of this work show that there is no simple correlation between the heavily affected depth of the alloy and the nickel, chromium, or iron content. Instead, there seem to be two successful alloy composition principles that work well for this application. Furthermore, the work shows that major improvements can be made in terms of both technical life-span and the cost-effectiveness of the VF application if the most appropriate alloy is selected. In this study, a replacement of the frequently used Alloy 253MA with Alloy 310S doubled the lifespan of full-scale VFs, reducing the average VF maintenance cost to half.

  • 55.
    Hariramabadran Anantha, Krishnan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    An Experimental Study to Understand the Localized Corrosion and Environment-Assisted Cracking Behavior of AISI 420-Martensitic Stainless Steel2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Motivation and aim: Currently steel molds are designed with cooling channels to reduce the solidification time of molten plastic within the mold to improve the productivity. As water is generally used as the cooling medium, corrosion and environment-assisted cracking (EAC) leading towards the dysfunction of mold, can increase the production downtime. This was observed in some cases. Hence the primary aim of this thesis is to study the corrosion and EAC behavior of a martensitic stainless steel (MSS) in Cl containing environment to further the current understanding thereby to optimize the existing alloy/s and to design and develop new steel grades.

    Methods: The MSS had been austenitised at 1020°C, and subsequently quenched in nitrogen gas at fast (3°C/s), and slow quenching rates (0.6°C/s). Then tempering was done at 250°C, and 500°C, respectively, twice for two hours. Microstructure was predicted and characterized using Thermocalc simulation, dilatometry, light optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, atomic force microscopy (AFM). Localized corrosion behavior was characterized using standard salt spray test, electrochemical experiments, scanning Kelvin probe force microscopy, in-situ AFM. Stress relaxation associated with 250°C, and 500°C tempering was characterized by a new method for both fast (FQ) and slow quenched (SQ) conditions. Based on the %stress relaxation, initial loading levels were altered and the corresponding environment-assisted cracking behavior was investigated at two different loading levels.

    Results: Samples tempered at 250ºC exhibited higher corrosion resistance than samples tempered at 500ºC in both FQ and SQ conditions. FQ samples exhibited higher corrosion resistance with an ability to passivate than SQ samples when tempered at 250ºC. However, when tempered at 500°C, the corrosion resistance was poor for both FQ and SQ samples. These observed differences clearly indicate the strong influence of microstructure on the corrosion behavior of the material. There are preferential active sites in the microstructure, which dictate the sequence of corrosion events. Secondary Cr-rich carbides formed during 500ºC tempering apparently deteriorate the corrosion resistance in spite of their smaller sizes as compared to undissolved Cr-rich carbides.  Stress relaxation increased with increasing tempering temperature. In the FQ condition, 250°C temper exhibited superior EAC resistance than 500°C temper in both loading scenarios, indicating the dominant role of corrosion resistance in delaying the failure. Whereas in SQ condition, 500°C temper exhibited superior EAC resistance than 250°C temper in both loading scenarios, indicating the dominant role of applied stress in delaying the failure. The pitting susceptibility increased with increasing applied stress on both FQ and SQ conditions. The fractographic features suggest that the mechanism of failure was mixed mode involving both active path dissolution and hydrogen embrittlement, which could have been operative during the failure in varying magnitude in respective scenarios. 

    Conclusions: Based on this research work, it can be concluded that, in order to have a longer service life, both the localized corrosion behavior and the residual stresses are to be considered while recommending tempering temperature to mold makers.

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    An Experimental Study to Understand the Localized Corrosion and Environment (Electronic version)
  • 56.
    Hariramabadran Anantha, Krishnan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ejnermark, Sebastian
    Medvedeva, Anna
    Sjöström, Johnny
    Pan, Jinshan
    Corrosion Behavior of a Martensitic Stainless Steel AISI 420 Modified From a Mold Size Point of View2016Conference paper (Refereed)
  • 57.
    Hariramabadran Anantha, Krishnan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Örnek, Cem
    Ejnermark, Sebastian
    Medvedeva, Anna
    Sjöström, Johnny
    Pan, Jinshan
    Effect of residual stress on environmentally assisted cracking behavior of slow quenched AISI 420martensitic stainless steel tempered at 250°C and 500°CManuscript (preprint) (Other academic)
  • 58.
    Hariramabadran Anantha, Krishnan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Örnek, Cem
    Ejnermark, Sebastian
    Thuvander, Anders
    Medvedeva, Anna
    Sjöström, Johnny
    Pan, Jinshan
    Experimental and modelling study of the effects of tempering on the susceptibility to environment-assisted cracking of AISI 420 martensitic stainless steelManuscript (preprint) (Other academic)
  • 59.
    He, Yunjuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Corrosion protection and nanomechanical properties of waterborne acrylate-based coating with and without nanocellulose on carbon steel2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Corrosion protection is commonly achieved by applying a thin polymer coating on metal surfaces. In this doctoral thesis, a waterborne hydroxyacrylate-melamine copolymer coating was used for this purpose. The first step was to find the optimal curing conditions. To this end the effect of curing time at 180 °C on the conversion of the cross-linking reaction, surface topography, nanomechanical and nanowear properties were investigated using atomic force microscopy, AFM. The results demonstrated that optimal performance required 10 min curing at 180 °C. This resulted in 80% conversion of the cross-linking reaction, as well as good barrier performance with polarization resistance of the order of 109Ω·cm2during 35 days in 0.1 M NaCl solution as determined by Electrochemical Impedance Spectroscopy (EIS). It also resulted in minor surface roughness and high surface elastic modulus in the order of GPa. 

     

    This waterborne coating and its nanocomposite containing 0.5 wt.% cellulose nanocrystals (CNC) were systematically studied, focusing on their corrosion protection performance and the effect of environment and localized wear on the properties of the top surface. The results show that both coatings have high polarization resistance, Rp. For the matrix coating the polarization resistance displays a slightly decreasing trend with time, as expected for a barrier coating. In contrast, the CNC nanocomposite coating exhibits an unusual and unexpected increase in polarization resistance with time. The difference in the time dependence of Rp can be attributed to the reinforcement effect of CNC, which form strong hydrogen bonding interactions with the matrix coating. Further, the appearance of a second time constant in the corresponding EIS spectra implies formation of a more protective second layer at the metal-coating interface. The presence of this compact layer also contributes to the corrosion protection offered by the CNC nanocomposite coating. In addition, both coatings show only limited water-uptake during long term exposure to 0.1 M NaCl. The water up-take is too small to measurably change the coating capacitance, as studied by EIS. However, AFM studies of surface nanomechanical properties show that for the CNC nanocomposite some water penetration occurs, which irreversibly renders the surface softer.

     

    Inspired by the CNC nanocomposite coating and its favorable corrosion protective properties, 0.5 wt.% cellulose nanofibrils, CNF, nanocomposite coatings were also studied using the same methodologies. The results revealed that the CNF nanocomposite coating cannot provide efficient corrosion protection performance even over a period of 24 h. The measured polarization resistance decreases rapidly over time, and consistently water uptake is readily observed by analyzing coating capacitance using EIS technique. The substantial difference in corrosion protective properties of the CNC nanocomposite and the CNF nanocomposite are explained mainly from the perspective of microstructure, matrix-CNC or matrix-CNF interactions by using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show the presence of defects on the surface and in the bulk and absence of strong hydrogen bonding interactions between matrix and CNF. These are two reasons for why the CNC nanocomposite performs well in terms of corrosion protection, whereas the CNF nanocomposite does not. 

     

    In real applications good barrier coatings may also fail due to external forces such as erosion by wind and water, impact of solid particles or sliding motions against other objects, which may destroy the coating integrity. This motivated further studies of the matrix and the CNC nanocomposite, by focusing on their nanomechanical and nano-wear properties using local measurements by means of AFM. The effect of applied normal load, ranging from 50 – 400 nN, scanning speed, ranging from 1 – 20 µm/s, operating environment including air and water, as well as exposure to corrosive 0.1 M NaCl solution, were systematically studied and discussed.

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    fulltext
  • 60.
    He, Yunjuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Boluk, Yaman
    Univ Alberta, Dept Civil & Environm Engn, Edmonton, AB T6G 1H9, Canada.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden.
    Deltin, Tomas
    PTE Coatings AB, Hammarsvagen 4, SE-59432 Gamleby, Sweden.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden.
    Corrosion protective properties of cellulose nanocrystals reinforced waterborne acrylate-based composite coating2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 155, p. 186-194Article in journal (Refereed)
    Abstract [en]

    The present investigation highlights corrosion protection of carbon steel by a waterborne acrylate-based matrix coating, with and without reinforcement by cellulose nanocrystals, by using electrochemical impedance spectroscopy in 0.1 M NaCl solution over a period of 35 days. Interactions between cellulose nanocrystals and the matrix coating were demonstrated by Fourier transform infrared spectroscopy. The results show that both coatings have high barrier performance but different protective characteristics during long-term exposure. The differences can be attributed to the reinforcement effect of cellulose nanocrystals caused by hydrogen bonding interactions between cellulose nanocrystals and the matrix coating.

  • 61.
    He, Yunjuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dobryden, Illia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Deltin, Tomas
    PTE Coatings AB, Hammarsvagen 4, SE-59432 Gamleby, Sweden..
    Corkery, Robert W.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nano-scale mechanical and wear properties of a waterborne hydroxyacrylic-melamine anti-corrosion coating2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 457, p. 548-558Article in journal (Refereed)
    Abstract [en]

    Corrosion protection is commonly achieved by applying a thin polymer coating on the metal surface. Many studies have been devoted to local events occurring at the metal surface leading to local or general corrosion. In contrast, changes occurring in the organic coating after exposure to corrosive conditions are much less studied. In this article we outline how changes in the coating itself due to curing conditions, environmental and erosion effects can be investigated at the nanometer scale, and discuss how such changes would affect its corrosion protection performance. We focus on a waterborne hydroxyacrylic-melamine coating, showing high corrosion protection performance for carbon steel during long-term (approximate to 35 days) exposure to 0.1 M NaCl solution. The effect of curing time on the conversion of the crosslinking reaction within the coating was evaluated by fourier transform infrared spectroscopy (FTIR); the wetting properties of the cured films were investigated by contact angle measurement, and the corrosion resistance was studied by electrochemical impedance spectroscopy (EIS). In particular, coating nanomechanical and wear properties before and after exposure to 0.1 M NaCl, were evaluated by atomic force microscopy (AFM). Fiber-like surface features were observed after exposure, which are suggested to arise due to diffusion of monomers or low molecular weight polymers to the surface. This may give rise to local weakening of the coating, leading to local corrosion after even longer exposure times. We also find a direct correlation between the stick-slip spacing during shearing and plastic deformation induced in the surface layer, giving rise to topographical ripple structures on the nanometer length scale.

  • 62.
    He, Yunjuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Li, Gen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hwang, Ki-Hwan
    Claesson, Per Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nano-scale mechanical and wear properties of a corrosion protective coating reinforced by cellulose nanocrystals: initiation of coatingManuscript (preprint) (Other academic)
    Abstract [en]

    Organic coatings are commonly used for protection of substrate surfaces like metals and wood. In most cases they fulfil their purpose by acting as a barrier against unwanted substances such as oxygen, water or corrosive ions. However, with time coatings fail due to degradation caused by chemical reactions or wear by wind, water, impact of solid particles or sliding motions against other solid objects. In this work we focus on a nanocomposite coating having a hydroxyacrylate-melamine matrix and being reinforced by a small amount (0.5 wt.%) of cellulose nanocrystals. This nanocomposite is of interest as it has shown favourable corrosion protection properties on carbon steel. Here we investigate the nanomechanical and nanowear properties of the coating in air and in water, and we also explore how these properties are affected by exposure to a corrosive 0.1 M NaCl solution. Our data show that the nanomechanical properties of the coating surface is strongly affected by the environment (air or water), and that exposure to the corrosive solution affects the coating surface well before any deterioration of the corrosion protective properties are found. We suggest that our experimental methodology constitutes a powerful way to investigate and understand the initiation of coating degradation.

  • 63.
    Hedberg, Jonas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Blomberg, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    In the Search for Nanospecific Effects of Dissolution of Metallic Nanoparticles at Freshwater-Like Conditions: A Critical Review2019In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, no 8, p. 4030-4044Article in journal (Refereed)
    Abstract [en]

    Knowledge on relations between particle properties and dissolution/transformation characteristics of metal and metal oxide nanoparticles (NPs) in freshwater is important for risk assessment and product development. This critical review aims to elucidate nanospecific effects on dissolution of metallic NPs in freshwater and similar media. Dissolution rate constants are compiled and analyzed for NPs of silver (Ag), copper (Cu), copper oxide/hydroxide (CuO, Cu(OH) 2 ), zinc oxide (ZnO), manganese (Mn), and aluminum (Al), showing largely varying (orders of magnitude) constants when modeled using first order kinetics. An effect of small primary sizes (<15 nm) was observed, leading to increased dissolution rate constants and solubility in some cases. However, the often extensive particle agglomeration can result in reduced nanospecific effects on dissolution and also an increased uncertainty related to the surface area, a parameter that largely influence the extent of dissolution. Promising ways to model surface areas of NPs in solution using fractal dimensions and size distributions are discussed in addition to nanospecific aspects related to other processes such as corrosion, adsorption of natural organic matter (NOM), presence of capping agents, and existence of surface defects. The importance of the experimental design on the results of dissolution experiments of metal and metal oxide NPs is moreover highlighted, including the influence of ionic metal solubility and choice of particle dispersion methodology.

  • 64.
    Hedberg, Jonas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Fransson, K.
    Prideaux, Sonja
    Roos, S.
    Jönsson, C.
    Odnevall Wallinder, Inger
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Improving the life cycle impact assessment of metal ecotoxicity: Importance of chromium speciation, water chemistry, and metal release2019In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 6, article id 1655Article in journal (Refereed)
    Abstract [en]

    Investigations of metal ecotoxicity in life cycle assessment (LCA) and life cycle impact assessment (LCIA) are becoming important tools for evaluating the environmental impact of a product or process. There is, however, improvement needed for LCIA of metal ecotoxicity in order to make this assessment more relevant and robust. In this work, three issues within the LCIA of metal ecotoxicity are investigated, mainly focusing on topics related to stainless steel manufacturing. The first issue is the importance of considering regional water chemistry when constructing the characterization factor (CF). A model freshwater of relevance for stainless steel manufacturing in a region of Sweden was created with chemistry different from available options. The second issue is related to the lack of consideration on changes in speciation of Cr(VI) in freshwater for a given emission, as Cr(VI) to some extent will be reduced to Cr(III). Two new options are suggested based on relationships between the Cr(VI)-total Cr ratio as a way to improve the relevancy of LCIA for Cr(VI) in freshwater. The last issue is how to treat metal release from slags in LCIA. Metal release from slags was shown to vary significantly between different ways of modelling slag emissions (differences in total metal content, slag leaching tests, estimated emissions to groundwater). 

  • 65.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dobryden, Illia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chaudhary, Himanshu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Synergistic effects of metal-induced aggregation of human serum albumin2019In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 173, p. 751-758Article in journal (Refereed)
    Abstract [en]

    Exposure to cobalt (Co), chromium (Cr), and nickel (Ni) occurs often via skin contact and from different dental and orthopedic implants. The metal ions bind to proteins, which may induce structural changes and aggregation, with different medical consequences. We investigated human serum albumin (HSA) aggregation in the presence of Co-II, Cr-III, and/or Ni-II ions and/or their nanoparticle precipitates by using scattering, spectroscopic, and imaging techniques, at simulated physiological conditions (phosphate buffered saline - PBS, pH 7.3) using metal salts that did not affect the pH, and at HSA:metal molar ratios of up to 1:8. Co ions formed some solid nano particles in PBS at the investigated conditions, as determined by nanoparticle tracking analysis, but the Cr-III anions and Ni-II ions remained fully soluble. It was found that all metal ions induced HSA aggregation, and this effect was significantly enhanced when a mixture of all three metal ions was present instead of any single type of ion. Thus, the metal ions induce aggregation synergistically. HSA aggregates formed linear structures on a mica surface in the presence of Cr-III ions. A clear tendency of aggregation and linearly aligned aggregates was seen in the presence of all three metal ions. Spectroscopic investigations indicated that the majority of the HSA molecules maintained their alpha helical secondary structure and conformation. This study highlights the importance of synergistic effects of metal ions and/or their precipitates on protein aggregation, which are highly relevant for implant materials and common exposures to metals.

  • 66.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Erfani, Behnaz
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Matura, Mihály
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden ; Unit of Occupational and Environmental Dermatology, Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.
    Lidén, Carola
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Chromium(III) release from chromium-tanned leather elicits allergic contact dermatitis: a use test study.2018In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 78, no 5, p. 307-314Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Chromium (Cr) is a common skin sensitizer. The use of Cr(VI) in leather is restricted in the EU, but that of Cr(III) is not.

    OBJECTIVES: To assess whether prolonged exposure to Cr-tanned leather with mainly Cr(III) release may elicit allergic contact dermatitis in Cr-allergic individuals.

    METHOD: Ten Cr-allergic subjects and 22 controls were patch tested with serial dilutions of Cr(III) and Cr(VI), and with leather samples. They then conducted a use test with a Cr-tanned and a Cr-free leather bracelet over a period of 3 weeks, for 12 h per day. Cr deposited on the skin from the bracelets was measured in the controls, and the diphenylcarbazide test for Cr(VI) and extraction tests for Cr(III) and Cr(VI) were conducted for the different leathers.

    RESULTS: Four of 10 Cr-allergic subjects developed positive reactions to the Cr-tanned bracelet within 7-21 days, whereas only 1 of 10 had a positive patch test reaction to this leather. Cr released from the Cr-tanned leather was most probably entirely Cr(III), with a quantifiable amount being deposited on the skin.

    CONCLUSIONS: This study strongly suggests that prolonged and repeated exposure to Cr-tanned leather with mainly Cr(III) release is capable of eliciting allergic contact dermatitis in Cr-allergic individuals.

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    fulltext
  • 67.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Uter, Wolfgang
    Univ Erlangen Nurnberg, Dept Med Informat Biometry & Epidemiol, Erlangen, Germany..
    Banerjee, Piu
    Guys Hosp, St Johns Inst Dermatol, London, England.;Lewisham & Greenwich NHS Trust, London, England..
    Lind, Marie-Louise
    Stockholm Cty Council, Ctr Occupat & Environm Med, Stockholm, Sweden..
    Steengaard, Sanne Skovvang
    Univ Hosp Herlev Gentofte, Natl Allergy Res Ctr, Hellerup, Denmark..
    Teo, Ying
    Guys Hosp, St Johns Inst Dermatol, London, England..
    Liden, Carola
    Karolinska Inst, Inst Environm Med, Box 210, SE-17177 Stockholm, Sweden..
    Non-oxidative hair dye products on the European market: What do they contain?2018In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 79, no 5, p. 281-287Article in journal (Refereed)
    Abstract [en]

    Background: Hair dyeing is very common and may cause allergic contact dermatitis. Oxidative (often termed permanent or semi-permanent) hair dye products have constituted the focus of market surveys and toxicological risk assessments, while non-oxidative (semi-permanent, temporary or direct) products have not been assessed. Objectives: To identify the hair dye substances presently used in non-oxidative hair dye products in Europe. Methods: Ingredient label data on eligible products in 5 European countries were collected, and 289 different non-oxidative hair dye products were included in this study. Results: Up to 9 hair dye substances were present in each product. Sixty-eight individual hair dye substances were identified on the 289 product labels, and their occurrence ranged from 0.3% to 34%. There were differences concerning substances used and their number per product between products of different consistency and colour. Conclusions: The hair dye substances in non-oxidative hair dye products are different from those in oxidative hair dye products, and are currently not covered by patch test series. The toxicological and skin-sensitizing profile of the substances in non-oxidative hair dye products, as well as their concentrations, should be further investigated.

  • 68.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chevez, Federico Moncada
    Natl Autonomous Univ Honduras, Dept Publ Hlth, Fac Med Sci, Tegucigalpa, Honduras.;Cent Amer Network Informat & Advice Ctr Toxicol R, Tegucigalpa, Honduras.;Ctr Res & Dev Hlth Labour & Environm CIDSTA, Tegucigalpa, Honduras..
    Chromium(III), chromium(VI) and cobalt release from leathers produced in Nicaragua2019In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 80, no 3, p. 149-155Article in journal (Refereed)
    Abstract [en]

    Background: Leather exposure has been associated with chromium (Cr) and cobalt (Co) contact dermatitis. Cr(VI) in leather is now restricted to < 3 mg/kg in the EU. Cr(III) is not restricted. Objectives: To analyse 29 differently coloured Cr-tanned leather samples from two Nicaraguan tanneries, and to compare their release of Cr, Cr(VI) and Co with that of leathers produced in Europe. Methods: Cr, Cr(VI) and Co were extracted in phosphate buffer for 3 hours at 25 degrees C according to EN ISO 17075. Atomic absorption spectroscopy and spectrophotometry were used for detection of the metals in phosphate buffer. Results: There was no difference in total Cr or Cr(VI) release between European and Nicaraguan leathers. There was no association between Cr(VI) and total Cr release. Co was released primarily from leathers of one tannery. Cr(III) was released in significantly higher amounts than Cr(VI). Conclusions: Future investigations and regulations should focus on Cr(III) and Co as well as on Cr(VI).

  • 69.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Matura, Mihaly
    Unit of Occupational and Environmental Dermatology, Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.
    High release of hexavalent chromium into artificial sweat in a case of leather shoe–induced contact dermatitis2019In: Contact Dermatitis, Vol. 82, no 3, p. 179-181Article in journal (Refereed)
    Abstract [en]

    SectionsPDFToolsShare

    Cases of allergic contact dermatitis due to chromium caused by chromium‐tanned leather articles such as shoes and gloves are well‐known.1, 2 In the European Union, hexavalent chromium in new leather articles on the market is restricted to 3 mg/kg since 2015.3 A recent use‐test study showed that also trivalent chromium, the dominating form of chromium released from new leather articles,4 can elicit allergic reactions in chromium‐allergic individuals.5 For leather articles that are used for a prolonged period, data on the released chromium form are scarce, but one long‐term study indicates that the fraction of hexavalent chromium increases with duration of use.6

  • 70.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Div Surface & Corros Sci, Dept Chem, SE-10044 Stockholm, Sweden..
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Matura, Mihaly
    Stockholm Cty Council, Unit Occupat & Environm Dermatol, Ctr Occupat & Environm Med, Stockholm, Sweden.;Skaraborgs Hosp Skovde, Unit Dermatol, Skovde, Sweden..
    High release of hexavalent chromium into artificial sweat in a case of leather shoe-induced contact dermatitis2020In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 82, no 3, p. 179-+Article in journal (Other academic)
  • 71.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Znidarsic, Monika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Univ Ljubljana, Fac Chem & Chem Technol, Vecna Pot 113, SI-1000 Ljubljana, Slovenia.
    Herting, Gunilla
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Milosev, Ingrid
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Mechanistic insight on the combined effect of albumin and hydrogen peroxide on surface oxide composition and extent of metal release from Ti6Al4V2019In: Journal of Biomedical Materials Research - Part B Applied Biomaterials, ISSN 1552-4973, Vol. 107, no 3, p. 858-867Article in journal (Refereed)
    Abstract [en]

    The titanium–aluminium (6 wt%)–vanadium (4 wt%) (Ti6Al4V) alloy is widely used as an orthopedic and dental implant material due to its high corrosion resistance in such environments. The corrosion resistance is usually determined by means of electrochemical methods, which may not be able to detect other chemical surface reactions. Literature findings report a synergistic effect of the combination of the abundant protein albumin and hydrogen peroxide (H 2 O 2 ) on the extent of metal release and corrosion of Ti6Al4V. The objectives of this study were to gain further mechanistic insight on the interplay of H 2 O 2 and albumin on the metal release process of Ti6Al4V with special focus on (1) kinetics and (2) H 2 O 2 and albumin concentrations. This was accomplished mainly by metal release and surface oxide composition investigations, which confirmed the combined effect of H 2 O 2 and albumin on the metal release process, although not detectable by electrochemical open circuit potential measurements. A concentration of 30 mM H 2 O 2 induced substantial changes in the surface oxide characteristics, an oxide which became thicker and enriched in aluminum. Bovine serum albumin (BSA) seemed to be able to deplete this aluminum content from the outermost surface or at least to delay its surface enrichment. This effect increased with increased BSA concentration, and for time periods longer than 24 h. This study hence suggests that short-term (accelerated) corrosion resistance measurements are not sufficient to predict potential health effects of Ti6Al4V alloys since also chemical dissolution mechanisms play a large role for metal release, possibly in a synergistic way.

  • 72.
    Hermanowska, Malgorzata
    et al.
    Univ Southern Denmark, Dept Phys & Chem, Odense M, Denmark.;Univ Southern Denmark, MEMPHYS, Odense M, Denmark..
    Bijelic, Goran
    KTH, School of Chemical Science and Engineering (CHE).
    Ciobanasu, Corina
    Univ Bonn, Inst Phys & Theoret Chem, Bonn, Germany..
    Kubitscheck, Ulrich
    Univ Bonn, Inst Phys & Theoret Chem, Bonn, Germany..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Klosgen, Beate M.
    Univ Southern Denmark, Dept Phys & Chem, Odense M, Denmark.;Univ Southern Denmark, MEMPHYS, Odense M, Denmark..
    Charges in phospholipid layers2009In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 96, no 3, p. 18A-18AArticle in journal (Other academic)
  • 73.
    Herting, Gunilla
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Karlsson, Maria-Elisa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    A novel method to assess mass loss of aluminium in concrete2018In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 69, no 12, p. 1811-1814Article in journal (Refereed)
    Abstract [en]

    A novel pickling procedure for aluminium is elaborated for successful removal of corrosion products on aluminium embedded and exposed in concrete, allowing subsequent mass loss evaluation. The current recommended standard procedures for mass loss evaluation of aluminium are not sufficiently effective, either leaving significant amounts of concrete and corrosion products on the aluminium surfaces after pickling, or containing hazardous chemicals. Removal of both concrete and corrosion products from the aluminium surfaces require a stepwise combination of an aqueous glycine solution, nitric acid at elevated temperature and careful manual removal of adherent concrete.

  • 74.
    Hjalmarsson, Nicklas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Attana AB, Stockholm, SE-11419, Sweden.
    Bergendal, Erik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Attana AB, Stockholm, SE-11419, Sweden.
    Wang, Yong-Lei
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Munavirov, Bulat
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Wallinder, Daniel
    Attana AB, SE-11419 Stockholm, Sweden..
    Glavatskih, Sergei
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University, Ghent, B-9000, Belgium.
    Aastrup, Teodor
    Attana AB, SE-11419 Stockholm, Sweden..
    Atkin, Rob
    Univ Western Australia, Sch Mol Sci, Perth, WA 6009, Australia..
    Furo, Istvan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Rutland, Mark W.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, Stockholm, SE-50115, Sweden.
    Electro-Responsive Surface Composition and Kinetics of an Ionic Liquid in a Polar Oil2019In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, no 48, p. 15692-15700Article in journal (Refereed)
    Abstract [en]

    The quartz crystal microbalance (QCM) has been used to study how the interfacial layer of an ionic liquid dissolved in a polar oil at low weight percentages responds to changes in applied potential. The changes in surface composition at the QCM gold surface depend on both the magnitude and sign of the applied potential. The time-resolved response indicates that the relaxation kinetics are limited by the diffusion of ions in the interfacial region and not in the bulk, since there is no concentration dependence. The measured mass changes cannot be explained only in terms of simple ion exchange; the relative molecular volumes of the ions and the density changes in response to ion exclusion must be considered. The relaxation behavior of the potential between the electrodes upon disconnecting the applied potential is more complex than that observed for pure ionic liquids, but a measure of the surface charge can be extracted from the exponential decay when the rapid initial potential drop is accounted for. The adsorbed film at the gold surface consists predominantly of ionic liquid despite the low concentration, which is unsurprising given the surtactant-like structures of (some of) the ionic liquid ions. Changes in response to potential correspond to changes in the relative numbers of cations and anions, rather than a change in the oil composition. No evidence for an electric field induced change in viscosity is observed. This work shows conclusively that electric potentials can be used to control the surface composition, even in an oil-based system, and paves the way for other ion solvent studies.

  • 75.
    Hore, Dennis K.
    et al.
    Univ Victoria, Dept Chem, Victoria, BC V8W 3V6, Canada..
    Tyrode, Eric
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Probing Charged Aqueous Interfaces Near Critical Angles: Effect of Varying Coherence Length2019In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 27, p. 16911-16920Article in journal (Refereed)
    Abstract [en]

    Angle-resolved vibrational sum frequency generation experiments have been used to study the silica-water interface as a function of ionic strength. Well below the critical angle, the sum frequency intensity increases up to 10(-4) M NaCl and then drops. However, near the critical angle, a plateau may be observed up to 10(-4) M. We first demonstrate that this is a result of the interaction of a long Debye length at low ionic strength with a long coherence length near the critical angles. In order to account for the behavior at the lowest concentrations where surface potentials are typically large, it is necessary to consider an electrostatic potential that extends into the bulk aqueous phase beyond the Debye-Huckel approximation. Because the extent of second- and third-order contributions to the nonlinear polarization can vary with ionic strength, but not with the angle of incidence, we perform a global fit to the experimental data using our proposed model to extract the relative magnitude of the two susceptibilities. The ionic strength dependence of this ratio points to the critical nature of the silanol deprotonation and the development of surface charge and illustrates how surface water molecules respond. These results highlight the importance of varying the coherence length in order to probe the water structure at charged interfaces.

  • 76. Hosseinpour, S.
    et al.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Gretic, Z. H.
    Mioc, E. K.
    Curkovic, H. O.
    Bochmann, S.
    Bachmann, J.
    Waegner, V.
    Virtanen, S.
    Peukert, W.
    Self-assembled monolayers as corrosion inhibitors; indoor, marine and biologically relevant exposure2017In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017Conference paper (Refereed)
  • 77. Hou, R. -Q
    et al.
    Zhang, Fan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Jiang, P. -L
    Dong, S. -G
    Pan, Jinshan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Lin, C. -J
    Corrosion inhibition of pre-formed mussel adhesive protein (Mefp-1) film to magnesium alloy2020In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 164, article id 108309Article in journal (Refereed)
    Abstract [en]

    A range of ex situ and in situ analytical techniques were applied to gain insights into the formation and properties of the pre-formed Mefp-1 film on magnesium-1.0 wt.% calcium (Mg-1.0Ca) alloy. The results revealed that the Mefp-1 film pre-formed at pH 4.6 shows a net-like structure, whereas it is more packed at pH 8.5. in situ scanning micro-reference electrode technique results demonstrated the Mefp-1 films formed at both pH can effectively inhibit the localised corrosion of Mg-1.0Ca alloy. Moreover, the film pre-formed at pH 4.6 provides an increasing corrosion inhibition to Mg-1.0Ca alloy during 7 days of exposure.

  • 78.
    Hägg Mameng, Sukanya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Localised corrosion and atmospheric corrosion of stainless steels2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This research is focused on defining limiting conditions for corrosion of stainless steels. The aim of the first part (Papers I-IV) was to understand the role of alloying level and environmental parameters on localised corrosion in aqueous conditions. Testing was done with a combination of short-term electrochemical and long-term immersion experiments. Results show that the chloride ion concentration and temperature are the main factors that affect the localised corrosion resistance. The presence of residual chlorine is also significant, since it leads to the ennoblement of the corrosion potential. If the corrosion potential exceeds the breakdown potential, the stainless steel will suffer from localised corrosion. Oxygen content and pH were identified as additional factors influencing the corrosivity of the environment.

    The aim of second part (Papers V-VIII) was to present information about the effect of alloying level, surface condition and environmental conditions on atmospheric corrosion resistance in Middle-East environments. Field exposure tests were performed and supplemented by laboratory aqueous corrosion tests. Results demonstrate that a higher alloying level (in both the bulk material and the surface), plus a smoother and cleaner surface gave an improvement in the corrosion performance and resistance to aesthetic degradation. Chloride and sulphate are the main surface contaminants found in the Middle East atmosphere. Stainless steels exposed in sheltered conditions showed a better atmospheric corrosion resistance than in open conditions. Three factors are considered to contribute to this difference: a very low rainfall, more condensation leading to corrosion in the open conditions and a higher level of beneficial sulphate in the deposits in sheltered conditions. The results showed a reasonable correlation between laboratory pitting corrosion tests and atmospheric field tests.

    The results from this thesis provide reference data to aid selection of appropriate stainless steel grades. Results can also be used to help understand the limits for use of stainless steels in different conditions in both aqueous environments and in the atmosphere.

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  • 79.
    Hägg Mameng, Sukanya
    et al.
    Avesta Research Center, Outokumpu Stainless AB, Avesta, Sweden.
    Pettersson, Rachel
    Jernkontoret, The Swedish Steel Producers’ Association Stockholm, Stockholm, Sweden.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wegrelius, Lena
    Avesta Research Center, Outokumpu Stainless AB, Avesta, Sweden.
    Atmospheric Corrosion Resistance of Stainless Steel: Results of a Field Exposure Program in the Middle-East2016In: Berg- und Huttenmännische Monatshefte (BHM), ISSN 0005-8912, E-ISSN 1613-7531, Vol. 161, no 1, p. 33-43Article in journal (Refereed)
    Abstract [en]

    Stainless steels have been widely used as architectural and construction materials because of their high degree of corrosion resistance, unique aesthetic quality, and stability in an unpolluted atmosphere. Although stainless steel is highly corrosion resistant, localized corrosion can occur in certain environments, especially in marine atmospheric conditions if the appropriate grade is not used. Exposure of stainless steel to an environment more aggressive than the limiting conditions may be harmful to its aesthetic appearance and ultimately even to its load-bearing capacity. Selecting a suitable stainless steel grade requires knowledge of the actual location of the application and the atmospheric conditions. In terms of materials selection, the austenitic stainless steel grade 316/316L has proved a very popular choice for architectural applications in many locations, but it is not always suitable at demanding sites such as marine environments in the Middle-East. In such cases the use of a higher-performance grade, often in combination with a good surface finish and established cleaning routines, is required to maintain pristine surfaces.

    The main objective of this paper is to present information about the atmospheric corrosion resistance of a number of stainless steels in the Middle-East at a marine site. The results obtained are analysed and discussed in terms of factors affecting atmospheric corrosion of stainless steel such as the, alloying element level, surface roughness, surface treatment, and microclimate.

  • 80.
    Hägg Mameng, Sukanya
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Pettersson, RachelLeygraf, ChristopherKTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.Wegrelius, Lena
    Effect of surface finishes on the atmospheric corrosion of duplex grade UNS S32205: results of a field exposure program in Dubai2016Conference proceedings (editor) (Other (popular science, discussion, etc.))
    Abstract [en]

    The duplex grade UNS S32205 is an excellent choice in many marine environments where UNS S31603 is on the borderline in regards to atmospheric corrosion resistance. The properties of S32205 make it well suited for construction with respect to strength, reduced maintenance, durability and long-term service. In marine environments the use of a sufficiently highly alloyed stainless steel, often in combination with a good surface finish and adequate maintenance, is required to maintain pristine surfaces.

    The main objective with this paper is to present information about the effect of different surface finishes on the corrosion and aesthetic appearance of the duplex grade S32205 exposed at a marine test site in Dubai, UAE. The results obtained include the effect of characteristics such as surface roughness, surface treatment and surface orientation after several years of exposure. Results show that duplex grade UNS S32205 can be considered for architectural materials in severe marine locations such as the Dubai site. A smooth surface and an appropriate surface treatment give improved corrosion resistance. Chromium and silicon in the passive film were found to be beneficial in terms of resistance to aesthetic degradation. A correlation was observed between aqueous corrosion resistance measured in laboratory pitting corrosion tests and the atmospheric field test results.

  • 81. Jin, Ying
    et al.
    Lai, Zhaogui
    Bi, Peng
    Yan, Songtao
    Wen, Lei
    Wang, Yongchao
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Combining lithography and capillary techniques for local electrochemical property measurements2018In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 87, p. 53-57Article in journal (Refereed)
    Abstract [en]

    The relationships between composition, microstructure and electrochemical properties are of fundamental importance in understanding the corrosion of multiphase materials and thus in aiding in the design of new materials. A local electrochemical test system which combines a capillary device with a photolithographic mask has been developed to investigate the local electrochemical properties of a predefined micron-sized area with greater reliability and versatility than existing approaches. Independent electrochemical measurements were conducted on the different phases of a 2205 duplex stainless steel in NaCl solution, demonstrating the feasibility of the developed test system.

  • 82.
    Judith Cruz, M.
    et al.
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Makarova, Irina V.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Lappeenranta Univ Technol, Sch Engn Sci, Dept Separat & Purificat, Skinnarilankatu 34, FI-53850 Lappeenranta, Finland..
    Kharitonov, Dmitry S.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Polish Acad Sci, Jerzy Haber Inst Catalysis & Surface Chem, Krakow, Poland..
    Dobryden, Illia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chernik, Alexander A.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS..
    Grageda, Mario
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Ushak, Svetlana
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Corrosion properties of nickel coatings obtained from aqueous and nonaqueous electrolytes2019In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 51, no 9, p. 943-953Article in journal (Refereed)
    Abstract [en]

    Nickel was deposited on a copper substrate from aqueous and nonaqueous ethanol electrolytes. X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and chronovoltametry, scanning electron microscopy, and atomic force microscopy were used to study the effect of the solvent on the surface and corrosion properties of the Ni coatings formed. Unifom and relatively smooth Ni films were obtained as measured with microscopy techniques. The formation of a passive film in acidic, alkaline, and neutral chloride-containing media was confirmed with X-ray photoelectron spectroscopy. The water-based nickel-plating electrolyte makes it possible to deposit coatings with higher corrosion resistance as compared with coatings deposited from ethanol electrolyte in NaOH and NaCl media. The proposed mechanism of corrosion in a 0.5 M H2SO4 solution involves cycles of active-passive surface behavior due to its passivation by corrosion products.

  • 83.
    Kaestner, Bernd
    et al.
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hermann, Peter
    PTB, Abbestr 2-12, D-10587 Berlin, Germany.;Deutschland GmbH & Co KG, West Pharmaceut Serv, Stolberger Str 21-41, D-52249 Eschweiler, Germany..
    Kruskopf, Mattias
    PTB, Bundesallee 100, D-38116 Braunschweig, Germany.;NIST, 100 Bur Dr, Gaithersburg, MD 20899 USA..
    Pierz, Klaus
    PTB, Bundesallee 100, D-38116 Braunschweig, Germany..
    Hoehl, Arne
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Hornemann, Andrea
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Ulrich, Georg
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Fehmel, Jakob
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Patoka, Piotr
    Free Univ Berlin, Inst Chem & Biochem, Phys Chem, Takustr 3, D-14195 Berlin, Germany..
    Ruehl, Eckart
    Free Univ Berlin, Inst Chem & Biochem, Phys Chem, Takustr 3, D-14195 Berlin, Germany..
    Ulm, Gerhard
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Infrared Nanospectroscopy of Phospholipid and Surfactin Monolayer Domains2018In: ACS OMEGA, ISSN 2470-1343, Vol. 3, no 4, p. 4141-4147Article in journal (Refereed)
    Abstract [en]

    A main challenge in understanding the structure of a cell membrane and its interactions with drugs is the ability to chemically study the different molecular species on the nanoscale. We have achieved this for a model system consisting of mixed monolayers (MLs) of the biologically relevant phospholipid 1,2-distearoyl-sn-glycero-phosphatidylcholine and the antibiotic surfactin. By employing nano-infrared (IR) microscopy and spectroscopy in combination with atomic force microscopy imaging, it was possible to identify and chemically detect domain formation of the two constituents as well as to obtain IR spectra of these species with a spatial resolution on the nanoscale. A novel method to enhance the near-field imaging contrast of organic MLs by plasmon interferometry is proposed and demonstrated. In this technique, the organic layer is deposited on gold and ML graphene substrates, the latter of which supports propagating surface plasmons. Plasmon reflections arising from changes in the dielectric environment provided by the organic layer lead to an additional contrast mechanism. Using this approach, the interfacial region between surfactin and the phospholipid has been mapped and a transition region is identified.

  • 84.
    Kanerva, M.
    et al.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland.;Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Besharat, Zahra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Parnanen, T.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Jokinen, J.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Honkanen, M.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Sarlin, E.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Göthelid, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Schlenzka, D.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Miniature CoCr laser welds under cyclic shear: Fatigue evolution and crack growth2019In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 99, p. 93-103Article in journal (Refereed)
    Abstract [en]

    Miniature laser welds with the root depth in the range of 50-300 pm represent air-tight joints between the components in medical devices, such as those in implants, growth rods, stents and various prostheses. The current work focuses on the development of a fatigue test specimen and procedure to determine fatigue lives of shear-loaded laser welds. A cobalt-chromium (CoCr) alloy is used as a benchmark case. S-N graphs, damage process, and fracture surfaces are studied by applying x-ray analysis, atomic force microscopy, and scanning electron microscopy both before and after the crack onset. A non-linear material model is fitted for the CoCr alloy to run finite element simulations of the damage and deformation. As a result, two tensile-loaded specimen designs are established and the performance is compared to that of a traditional torque-loaded specimen. The new generation specimens show less variation in the determined fatigue lives due to well-defined crack onset point and, therefore, precise weld seam load during the experiments. The fatigue damage concentrates to the welded material and the entire weld experiences fatigue prior to the final, fracture-governed failure phase. For the studied weld seams of hardened CoCr, a regression fatigue limit of 10.8-11.8 MPa, where the stress refers to the arithmetic average shear stress computed along the region dominated by shear loading, is determined.

  • 85.
    Kanerva, M.
    et al.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland. Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Besharat, Zahra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Pärnänen, T.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Jokinen, J.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Honkanen, M.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Sarlin, E.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Göthelid, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Schlenzka, D.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Automatization and stress analysis data of CoCr laser weld fatigue tests2019In: Data in Brief, E-ISSN 2352-3409, Vol. 26, article id 104374Article in journal (Refereed)
    Abstract [en]

    This work includes raw and analyzed test data when using a recently developed fatigue test method for miniature laser welds in cobalt-chromium (CoCr) alloy joints [1]: 10.1016/j.jmbbm.2019.07.004. The automization of fatigue tests is crucial for saving costs and personnel resources and that is the reason why the atomization threshold and the resulting spectrum data related to CoCr welds are provided here. The finite element method based stress computation output is provided related to shearing-mode tests to support the dataset as a whole. In addition, the compositional data of the parent material and the laser weld are given.

  • 86.
    Kawada, S.
    et al.
    Japan.
    Watanabe, Seiya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Sasaki, S.
    Japan.
    Miyatake, M.
    Japan.
    Evaluation of friction behavior and surface interactions of cyano-based ionic liquids under different sliding contacts and high vacuum condition2018In: Lubricants, ISSN 2075-4442, Vol. 6, no 3, article id 69Article in journal (Refereed)
    Abstract [en]

    The friction coefficients of ionic liquids were evaluated by many investigations. Most investigations used fluorine-based ionic liquids as lubricants. However, these ionic liquids produce the corrosion wear. This investigation focuses on the use of cyano-based ionic liquids as lubricants. Compared to fluorine-based ionic liquids, cyano-based ionic liquids exhibit high friction coefficients against steel material. This work examines how the friction coefficients of cyano-based ionic liquids are influenced by the type of sliding material used (AISI 52100, TiO2, and tetrahedral amorphous carbon). TiO2 lubricated with 1-ethyl-3-methylimidazolium tricyanomethanide, and ta-C lubricated with 1-butyl-1methylpyrrolidinium tetracyanoborate exhibited very low friction coefficients, smaller than fluorine-based ionic liquids. Time-of-Flight Secondary Ion Mass Spectrometry analysis showed that anions adsorb onto the worn surface, suggesting that anion adsorption is a critical parameter influencing friction coefficients. Quadrupole Mass Spectrometry measurements revealed that cations decompose on the nascent surface, preventing adsorption on the worn surface. These results suggest that low friction coefficients require the decomposition of cations and adsorption of anions. The reactivity of nascent surface changes with the sliding material used due to varying catalytic activity of the nascent surfaces.

  • 87. Kawada, S.
    et al.
    Watanabe, Seiya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Tadokoro, C.
    Sasaki, S.
    Effects of Alkyl Chain Length of Sulfate and Phosphate Anion-Based Ionic Liquids on Tribochemical Reactions2018In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 66, no 1, article id 8Article in journal (Refereed)
    Abstract [en]

    Ionic liquids are expected to become increasingly popular lubricants as they feature a number of attractive properties. This investigation focused on sulfate and phosphate anion-based ionic liquids and the improvement in lubricating performance with the addition of these anions. However, the detailed lubricating mechanism and effect of alkyl chain length on tribochemical reactions are unclear. This study investigates tribochemical reaction processes using a quadrupole mass spectrometer (Q-MS) and X-ray photoelectron spectroscopy. Seven types of ionic liquids: 1-ethyl-3-methylimidazolium hydrogensulfate ([EMIM][HSO4]), 1-ethyl-3-methylimidazolium methylsulfate ([EMIM][MSU]), 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][ESU]), 1-ethyl-3-methylimidazolium n-octylsulfate ([EMIM][OSU]), 1-ethyl-3-methylimidazolium dimethyl phosphate ([EMIM][DMP]), 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]), and 1-ethyl-3-methylimidazolium dibutyl phosphate ([EMIM][DBP]), were selected as lubricants. The friction coefficient of sulfate anion-based ionic liquids increased as their alkyl chain lengthened. However, wear scar diameter in this case showed the opposite tendency. The friction coefficient and wear scar diameter of phosphate anion-based ionic liquids increased with an increase in the alkyl chain length. Q-MS results indicated that the main outgassing components during sliding were the cation components, whereas the anion remained on the sliding surface and formed a tribofilm. The ionic liquids with short alkyl chains reacted with the sliding surface easily and led to very low friction. However, corrosive wear occurred in the case of the sulfate anion. On the other hand, anions with long alkyl chains underwent gradual tribochemical reactions because that led the mitigation of contact with nascent surface. The phosphate-based ionic liquids with long alkyl chains were unable to cause the lubricating effect due to low reactivity.

  • 88. Kawada, S.
    et al.
    Watanabe, Seiya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Tadokoro, C.
    Tsuboi, R.
    Sasaki, S.
    Lubricating mechanism of cyano-based ionic liquids on nascent steel surface2018In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 119, p. 474-480Article in journal (Refereed)
    Abstract [en]

    This study investigates the lubricating mechanism of cyano-based ionic liquids on steel surfaces using Q-MS, ToF-SIMS, and TGA. [EMIM][DCN], [EMIM][TCC], [EMIM][TCB], [BMPL][DCN], [BMPL][TCC], and [BMPL][TCB] were selected as lubricants. [EMIM][TCB] exhibited the highest friction coefficient. The others exhibited very low friction coefficients of less than 0.08. Q-MS analysis indicated that the cation components were detected in outgassing during sliding tests. However, anion components were not detected. ToF-SIMS results showed that the anions remained on the worn surfaces which would lead low friction coefficients. To achieve low friction coefficient, the tribo-decomposition of the ionic liquids and adsorption of anion were required. TGA indicated thermal stability was an index for tribo-decomposition on the nascent steel surface.

  • 89. Kawada, Shouhei
    et al.
    Sato, Keisuke
    Watanabe, Seiya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Sasaki, Shinya
    Lubricating property of cyano-based ionic liquids against hard materials2017In: Journal of Mechanical Science and Technology, ISSN 1738-494X, E-ISSN 1976-3824, Vol. 31, no 12, p. 5745-5750Article in journal (Refereed)
    Abstract [en]

    Ionic liquids are expected to be used as a new lubricants and lubricant additives because of their unique properties. However, cyano-based ionic liquids have exhibited poor lubricating property with steel/steel contacts. We evaluated the lubricating properties of cyano-based ionic liquids with steel/hard materials contacts. TiO2, Al2O3, and tetrahedral amorphous carbon (ta-C) DLC were used as hard materials. Six types of ionic liquids, as combination of two types of cations ([EMIM], [BMPL]) and three types of cyanide anions ([DCN], [TCC] and [TCB]), were selected. In sliding tests of steel/TiO2 and steel/Al2O3 lubricated with [EMIM][DCN], [BMPL][DCN], [EMIM][TCC], [BMPL][TCC] exhibited low friction coefficients of less than 0.1. In addition, steel/Al2O3 and steel/ta-C DLC lubricated with [BMPL][TCB] exhibited very low friction coefficients less than 0.05. On the other hand, high friction coefficients were observed at steel/TiO2 and steel/Al2O3 contacts lubricated with [EMIM][TCB] and steel/ta-C DLC contact lubricated with [EMIM] cation group. Peeling of the ta-C DLC was observed when [EMIM] cation group was used. ToF-SIMS analysis indicated that the anion was adsorbed on the worn surfaces in the case of low frictional conditions. However, both ions were hardly observed in the case of high frictional conditions. It is considered that the ionic liquids underwent tribo-decomposition on the worn surfaces at low friction coefficient. To evaluate the degree of tribo-decomposition, Thermogravimetric analysis (TGA) was used. TGA results indicated that [EMIM][TCB], which exhibited high friction coefficient, had the most highest stability among all ionic liquids. Low stability ionic liquids, however, showed a tendency for low friction coefficient. These results suggest that lubricating properties are related to the stability of ionic liquids.

  • 90.
    Kharitonov, Dmitry S.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Sommertune, Jens
    RISE Res Inst Sweden, Surface Proc & Formulat, SE-11486 Stockholm, Sweden..
    Örnek, Cem
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Ryl, Jacek
    Gdansk Univ Technol, Dept Electrochem Corros & Mat Engn, 11-12 Narutowicza St, PL-80233 Gdansk, Poland..
    Kurilo, Irina I.
    Belarusian State Technol Univ, Organ Subst Technol Fac, Dept Phys Colloid & Analyt Chem, Minsk 220006, BELARUS..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Corrosion inhibition of aluminium alloy AA6063-T5 by vanadates: Local surface chemical events elucidated by confocal Raman micro-spectroscopy2019In: CORROSION SCIENCE, Vol. 148, p. 237-250Article in journal (Refereed)
    Abstract [en]

    Chemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on top of cathodic micrometre-sized IMPs, whereby suppressing oxygen reduction kinetics. The results suggest a two-step mechanism of corrosion inhibition in which V+5 species are first reduced to V+4 or V+3 species above cathodic IMPs, and then oxidized to mixed-valence V+5/V+4 polymerized compounds.

  • 91.
    Kharitonov, Dmitry S.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Electrochem Prod Technol & Mat Elect Eq, Minsk 220006, BELARUS..
    Örnek, Cem
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Swerea KIMAB, Dept Corros Energy & Proc Ind, SE-16440 Kista, Sweden..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Sommertune, Jens
    RISE Res Inst Sweden, Chem Mat & Surfaces, SE-11486 Stockholm, Sweden..
    Zharskii, Ivan M.
    Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Electrochem Prod Technol & Mat Elect Eq, Minsk 220006, BELARUS..
    Kurilo, Irina I.
    Belarusian State Technol Univ, Organ Subst Technol Fac, Dept Phys Colloid & Analyt Chem, Minsk 220006, BELARUS..
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Corrosion Inhibition of Aluminum Alloy AA6063-T5 by Vanadates: Microstructure Characterization and Corrosion Analysis2018In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, no 3, p. C116-C126Article in journal (Refereed)
    Abstract [en]

    Corrosion inhibition of aluminum alloy AA6063-T5 by vanadates (NaVO3) in 0.05 M NaCl solution has been investigated by electrochemical and weight loss measurements, and associated with microstructure and Volta potential data. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses confirmed the presence of micrometer-sized Fe-rich Al4.01MnSi0.74, Al1.69Mg4Zn2.31, and FeAl3 intermetallic phases (IMPs) and nanometer-sized CuAl2, ZnAl2, and Mg2Si precipitates in the microstructure. Scanning Kelvin probe force microscopy measurements showed Volta potential differences of up to 600 mV between the microstructure constituents indicating a high susceptibility to micro-galvanic corrosion, with interphase boundary regions exhibiting the highest propensity to corrosion. Most IMPs had cathodic character whereas some nanometer-sized Mg-rich particles exhibited anodic nature, with large Volta potential gradients within interphase regions of large cathodic particles. Electrochemical potentiodynamic polarization measurements indicated that the vanadates provided mixed corrosion inhibition effects, mitigating both oxygen reduction, occurring on cathodic IMPs, and anodic metal dissolution reaction, occurring on anodic sites, such as Mg2Si and interphase boundary regions. Electrochemical measurements indicated that the sodium metavanadate inhibitor blocks active metal dissolution, giving high inhibition efficiency (>95%) during the initial exposure, whereas long-term weight loss measurements showed that the efficacy decreases after prolonged exposure.

  • 92. Kocabaş, M.
    et al.
    Örnek, Cem
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Curioni, M.
    Cansever, N.
    Nickel fluoride as a surface activation agent for electroless nickel coating of anodized AA1050 aluminum alloy2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 364, p. 231-238Article in journal (Refereed)
    Abstract [en]

    In this study, the use of nickel fluoride tetrahydrate (NiF 2 ·4H 2 O) as a surface activator and sealant at the same time for the coating of electroless nickel-phosphorus (Ni-P) on anodized aluminum alloy AA1050 is proposed. The usage of the activator resulted in more efficient deposition of Ni-P, improved adhesion properties, and increased wear and friction behavior as opposed to non-activated conditions. Scanning electron microscopy (SEM) and confocal laser microscopy (CLM) analyses of ultramicrotome-cut cross sections of Ni-P coated specimens, surface-activated by NiF 2 ·4H 2 O, revealed a more well-structured metal-coating interface as opposed to non-activated conditions.

  • 93.
    Koppolu, Rajesh
    et al.
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Abitbol, Tiffany
    RISE Res Inst Sweden, Biosci & Mat Surface Proc & Formulat, S-11428 Stockholm, Sweden..
    Kumar, Vinay
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland.;Finland Ltd, VTT Tech Res Ctr, High Performance Fiber Prod, Espoo 02044, Finland..
    Jaiswal, Aayush Kumar
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Biosci & Mat Surface Proc & Formulat, S-11428 Stockholm, Sweden..
    Toivakka, Martti
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Continuous roll-to-roll coating of cellulose nanocrystals onto paperboard2018In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 10, p. 6055-6069Article in journal (Refereed)
    Abstract [en]

    There is an increased interest in the use of cellulose nanocrystal (CNC) films and coatings for a range of functional applications in the fields of material science, biomedical engineering, and pharmaceutical sciences. Most of these applications have been demonstrated on films and coatings produced using laboratory-scale batch processes, such as solvent casting, dip coating, or spin coating. For successful coating application of CNC suspensions using a high throughput process, several challenges need to be addressed: relatively high viscosity at low solids content, coating brittleness, and potentially poor adhesion to the substrate. This work aims to address these problems. The impact of plasticizer on suspension rheology, coating adhesion, and barrier properties was quantified, and the effect of different pre-coatings on the wettability and adhesion of CNC coatings to paperboard substrates was explored. CNC suspensions were coated onto pre-coated paperboard in a roll-to-roll process using a custom-built slot die. The addition of sorbitol reduced the brittleness of the CNC coatings, and a thin cationic starch pre-coating improved their adhesion to the paperboard. The final coat weight, dry coating thickness, and coating line speed were varied between 1-11 g/m(2), 900 nm-7 A mu m, and 2.5-10 m/min, respectively. The barrier properties, adhesive strength, coating coverage, and smoothness of the CNC coatings were characterized. SEM images show full coating coverage at coat weights as low as 1.5 g/m(2). With sorbitol as plasticizer and at coat weights above 3.5 g/m(2), heptane vapor and water vapor transmission rates were reduced by as much as 99% and 75% respectively. Compared to other film casting techniques, the process employed in this work deposits a relatively thick coating in significantly less time, and may therefore pave the way toward various functional applications based on CNCs. [GRAPHICS] .

  • 94.
    Koppolu, Rajesh
    et al.
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Lahti, Johanna
    Tampere Univ Technol, Paper Converting & Packaging, Tampere 33100, Finland..
    Abitbol, Tiffany
    RISE Res Inst Sweden, Bioecon Biorefinery & Energy, S-11428 Stockholm, Sweden..
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Kuusipalo, Jurkka
    Tampere Univ Technol, Paper Converting & Packaging, Tampere 33100, Finland..
    Toivakka, Martti
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Continuous Processing of Nanocellulose and Polylactic Acid into Multilayer Barrier Coatings2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 12, p. 11920-11927Article in journal (Refereed)
    Abstract [en]

    Recent years have seen an increased interest toward utilizing biobased and biodegradable materials for barrier packaging applications. Most of the abovementioned materials usually have certain shortcomings that discourage their adoption as a preferred material of choice. Nanocellulose falls into such a category. It has excellent barrier against grease, mineral oils, and oxygen but poor tolerance against water vapor, which makes it unsuitable to be used at high humidity. In addition, nanocellulose suspensions' high viscosity and yield stress already at low solid content and poor adhesion to substrates create additional challenges for high-speed processing. Polylactic acid (PLA) is another potential candidate that has reasonably high tolerance against water vapor but rather a poor barrier against oxygen. The current work explores the possibility of combining both these materials into thin multilayer coatings onto a paperboard. A custom-built slot-die was used to coat either microfibrillated cellulose or cellulose nanocrystals onto a pigment-coated baseboard in a continuous process. These were subsequently coated with PLA using a pilot-scale extrusion coater. Low-density polyethylene was used as for reference extrusion coating. Cationic starch precoating and corona treatment improved the adhesion at nanocellulose/baseboard and nanocellulose/PLA interfaces, respectively. The water vapor transmission rate for nanocellulose + PLA coatings remained lower than that of the control PLA coating, even at a high relative humidity of 90% (38 degrees C). The multilayer coating had 98% lower oxygen transmission rate compared to just the PLA-coated baseboard, and the heptane vapor transmission rate reduced by 99% in comparison to the baseboard. The grease barrier for nanocellulose + PLA coatings increased 5-fold compared to nanocellulose alone and 2-fold compared to PLA alone. This approach of processing nanocellulose and PLA into multiple layers utilizing slot-die and extrusion coating in tandem has the potential to produce a barrier packaging paper that is both 100% biobased and biodegradable.

  • 95.
    Kottwitz, Matthew
    et al.
    Univ Illinois, Dept Chem, 1209 W Calif St, Urbana, IL 61801 USA..
    Li, Yuanyuan
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Palomino, Robert M.
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Liu, Zongyuan
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Wang, Guangjin
    Hubei Engn Univ, Coll Chem & Mat Sci, Xiaogan 432000, Peoples R China.;Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Peoples R China..
    Wu, Qin
    Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA..
    Huang, Jiahao
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Timoshenko, Janis
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Senanayake, Sanjaya D.
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Balasubramanian, Mahalingam
    Argonne Natl Lab, Adv Photon Source, Lemont, IL 60439 USA..
    Lu, Deyu
    Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA..
    Nuzzo, Ralph G.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Univ Illinois, Dept Chem, 1209 W Calif St, Urbana, IL 61801 USA..
    Frenkel, Anatoly I.
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA.;Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Local Structure and Electronic State of Atomically Dispersed Pt Supported on Nanosized CeO22019In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 9, no 9, p. 8738-8748Article in journal (Refereed)
    Abstract [en]

    Single atom catalysts (SACs) have shown high activity and selectivity in a growing number of chemical reactions. Many efforts aimed at unveiling the structure-property relationships underpinning these activities and developing synthesis methods for obtaining SACs with the desired structures are hindered by the paucity of experimental methods capable of probing the attributes of local structure, electronic properties, and interaction with support-features that comprise key descriptors of their activity. In this work, we describe a combination of experimental and theoretical approaches that include photon and electron spectroscopy, scattering, and imaging methods, linked by density functional theory calculations, for providing detailed and comprehensive information on the atomic structure and electronic properties of SACs. This characterization toolbox is demonstrated here using a model single atom Pt/CeO2 catalyst prepared via a sol-gel-based synthesis method. Isolated Pt atoms together with extra oxygen atoms passivate the (100) surface of nanosized ceria. A detailed picture of the local structure of Pt nearest environment emerges from this work involving the bonding of isolated Pt2+ ions at the hollow sites of perturbed (100) surface planes of the CeO2 support, as well as a substantial (and heretofore unrecognized) strain within the CeO2 lattice in the immediate vicinity of the Pt centers. The detailed information on structural attributes provided by our approach is the key for understanding and improving the properties of SACs.

  • 96.
    Kozhuharov, Svilen
    et al.
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Radiom, Milad
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Maroni, Plinio
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Borkovec, Michal
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Persistence Length of Poly(vinyl amine): Quantitative Image Analysis versus Single Molecule Force Response2018In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 51, no 10, p. 3632-3639Article in journal (Refereed)
    Abstract [en]

    Single molecules of poly(vinyl amine) are analyzed in the adsorbed state by atomic force microscopy (AFM) in two different ways. First, high-resolution images of individual adsorbed polymers were recorded in monovalent electrolyte solutions. The backbone of the imaged polymers was digitized, and the directional correlation function and internal mean-square end-to-end distance were evaluated. These quantities were analyzed with the wormlike chain (WLC) model, and the persistence length was extracted. Second, individual polymer chains were picked up from the surface, and their force extension behavior was recorded in the same electrolyte solutions. These force profiles were also interpreted in terms of the WLC model, whereby the elastic contribution was also considered. Both techniques yield the persistence length of the polymer. From imaging one obtains a persistence length of about 1.6 nm, while the force experiments yield a value around 0.51 nm. We suspect that the force experiments reflect the intrinsic part of the persistence length, while the imaging experiments yield the persistence length including the electrostatic

  • 97.
    Lancaster, D. G.
    et al.
    Univ South Australia, Sch Engn, Laser Phys & Photon Devices Lab, Mawson Lakes, SA 5095, Australia.;Red Chip Photon Pty Ltd, Mawson Lakes, SA 5095, Australia..
    Otten, D. E.
    Univ South Australia, Sch Engn, Laser Phys & Photon Devices Lab, Mawson Lakes, SA 5095, Australia.;Red Chip Photon Pty Ltd, Mawson Lakes, SA 5095, Australia..
    Cernescu, A.
    NeaSpec GmBH, D-85540 Munich, Germany..
    Hebert, N. Bourbeau
    Univ Laval, Ctr Opt Photon & Laser, Quebec City, PQ G1V 0A6, Canada..
    Chen, G. Y.
    Univ South Australia, Sch Engn, Laser Phys & Photon Devices Lab, Mawson Lakes, SA 5095, Australia..
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Monro, T. M.
    Univ South Australia, Sch Engn, Laser Phys & Photon Devices Lab, Mawson Lakes, SA 5095, Australia.;Def Sci & Technol Org, Dept Def, Edinburgh, SA 5111, Australia..
    Genest, J.
    Univ Laval, Ctr Opt Photon & Laser, Quebec City, PQ G1V 0A6, Canada..
    An ultra-stable 2.9 mu m guided-wave chip laser and application to nano-spectroscopy2019In: APL PHOTONICS, ISSN 2378-0967, Vol. 4, no 11, article id 110802Article in journal (Refereed)
    Abstract [en]

    We present a configurable guided-wave planar glass-chip laser that produces low-noise and high-quality continuous-wave laser emission tunable from 2.82 to 2.95 mu m. The laser has a low threshold and intrinsic power and mode stability attributable to the high overlap of gain volume and pump mode defined by an ultrafast laser inscribed waveguide. The laser emission is single transverse-mode with a Gaussian spatial profile and M-x,y(2) similar to 1.05, 1.10. The power drift is similar to 0.08% rms over similar to 2 h. When configured in a spectrally free-running cavity, the guided-wave laser emits up to 170 mW. The benefit of low-noise and stable wavelength emission of this hydroxide resonant laser is demonstrated by acquiring high signal-to-noise images and spectroscopy of a corroded copper surface film with corrosion products containing water and hydroxide ions with a scattering-scanning near-field optical microscope.

  • 98.
    Lancaster, D. G.
    et al.
    Laser Physics and Photonic Devices Laboratory, School of Engineering, University of South Australia, Mawson Lakes, 5095 SA, Australia.
    Otten, D. E.
    Laser Physics and Photonic Devices Laboratory, School of Engineering, University of South Australia, Mawson Lakes, 5095 SA, Australia.
    Cernescu, A.
    NeaSpec GmBH, Munich-Haar D-85540, Germany.
    Hébert, N. B.
    entre d’optique, Photonique et Laser, Université Laval, Québec City, Québec G1V 0A6, Canada.
    Chen, G. Y.
    Laser Physics and Photonic Devices Laboratory, School of Engineering, University of South Australia, Mawson Lakes, 5095 SA, Australia.
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Monro, T. M.
    Laser Physics and Photonic Devices Laboratory, School of Engineering, University of South Australia, Mawson Lakes, 5095 SA, Australia Defence Science and Technology Organisation, Department of Defence, Edinburgh, SA 5111, Australia.
    Genest, J.
    entre d’optique, Photonique et Laser, Université Laval, Québec City, Québec G1V 0A6, Canada .
    An ultra-stable 2.9 μ m guided-wave chip laser and application to nano-spectroscopy2019In: APL Photonics, Vol. 4, no 11, article id 110802Article in journal (Refereed)
    Abstract [en]

    We present a configurable guided-wave planar glass-chip laser that produces low-noise and high-quality continuous-wave laser emission tunable from 2.82 to 2.95 µm. The laser has a low threshold and intrinsic power and mode stability attributable to the high overlap of gain volume and pump mode defined by an ultrafast laser inscribed waveguide. The laser emission is single transverse-mode with a Gaussian spatial profile and M2x,y ∼ 1.05, 1.10. The power drift is ∼0.08% rms over ∼2 h. When configured in a spectrally free-running cavity, the guided-wave laser emits up to 170 mW. The benefit of low-noise and stable wavelength emission of this hydroxide resonant laser is demonstrated by acquiring high signal-to-noise images and spectroscopy of a corroded copper surface film with corrosion products containing water and hydroxide ions with a scattering-scanning near-field optical microscope.There is a scarcity of laser platform architectures in the mid-infrared (Mid-IR) spectral region, which limits the development of new photonic-based technologies. New emerging laser geometries such as optically pumped waveguide (WG) lasers1,2 in the Mid-IR can motivate applications, with examples including atom trapping,3 laser surgery,4 and scattering-scanning near-field optical microscopy (s-SNOM), a technique to achieve nanospectroscopy of surfaces.5 More generally, laser development in the 2.1–4 μm spectral region is immature, with very few application examples demonstrated using these lasers. Candidate technologies that will mature in the coming years include semiconductor, solid-state, and soft-glass fiber lasers.It has recently been reported that type 1 interband cascade lasers (ICLs) can operate at room temperature, with continuous wave (CW) laser emission from a range of devices covering 1.9–3.3 µm.6 There are still open issues regarding quantification of the beam-quality, mode stability,7 and reliability. Low energy storage lifetimes and small mode volumes limit their suitability for high peak-power applications.The development of mid-IR solid-state lasers has a long history and is dominated by 4-level erbium-doped bulk crystal lasers that can lase at discrete wavelengths across a “spiky” 2.7–2.9 μm crystal-field split (Stark dominated) transition.8,9 These crystalline lasers are based on external cavity defined laser cavity modes, where the beam quality, divergence, and pointing stability are subject to the dynamics of thermal lensing, and the overlap of the pump and cavity modes. In addition, high thresholds due to large pump mode-volumes mean that water cooling of the laser crystal is typically implemented to control thermal lensing.Transition metal Cr3+ doped ZnSe is an interesting evolving laser gain material, and recent work has reported improved optical quality that realizes the CW output in a bulk laser architecture achieving multi-watt-level performance and a tuning range of 1.9–3 µm.10To improve the performance of such bulk material lasers, or even to achieve lasing, low-loss waveguides are required. For instance, rare-earth-doped fluorozirconate glass required a fiber geometry to lase,11 but, in practice, such soft-glass fibers are fragile and difficult to manufacture. For low power applications, these challenges can be overcome when waveguide-in-bulk geometries were achieved,12 enabled by ultrafast laser inscription (ULI) techniques.13,14Ultrafast laser inscription (ULI) is a postprocessing technique that can be used to fabricate low-loss waveguides in bulk doped substrates.15,16 By incorporating ULI waveguides in solid-state gain media, the laser threshold is reduced by the intrinsic overlap of the pump and cavity mode, with the added benefit of ensuring fundamental transverse-mode operation. These factors mean that ULI waveguides can allow lasing transitions in bulk gain materials that are generally not practical. For instance, another laser material that has benefitted from ULI waveguides is transition metal doped Cr:ZnSe planar waveguide lasers operating within 2–3 µm,17 with waveguides greatly simplifying the required cavity designs.In 2013, we reported first the operation of a Ho-doped fluorozirconate glass (ZrF4, BaF4, LaF4, AlF3, and NaF3:ZBLAN) chip laser at ∼2.9 μm.18 However, its continuous-wave laser performance was marred by unstable pulsed emission as the population was “bottlenecking” in the Ho terminal 5I7 laser level (μs pulses at 100–300 kHz). For reference, the HoPr energy levels are shown in Fig. 3(b). In this work, we report the elimination of bottlenecking for this 2.9 µm transition by addition of low concentration Pr3+ which provides a pathway to de-excite the Ho 5I7 population, consistent with earlier work in HoPr ZBLAN fiber lasers.19 Our motivation to demonstrate the improved continuous-wave (CW) performance from this 2.9 μm chip laser architecture is to set a foundation for further development toward mode-locking, Q-switching, and single-frequency operation.This waveguide laser we report here exhibits noteworthy CW performance, with low power rms fluctuations of ∼0.08% over 2 h in a grating stabilized cavity, and power up to 170 mW when configured in a contiguous cavity [described in Fig. 1(b)]. With a Littrow-configured diffraction grating, the laser is tunable from 2820 nm to 2950 nm. Beam quality is almost diffraction limited and symmetrical with M2x,y ∼ 1.05, 1.10. These near-ideal performance metrics are due to a combination of efficient optically pumped broadband gain near 2.9 µm, robust antireflection dielectric coatings on the chip, low-loss single-transverse-mode waveguides, and a simple and efficient cavity design. These characteristics are essential to meet the stringent requirements for long-term, maintenance-free precision applications. The wide and flat gain profile, as well as high upper state storage lifetimes (∼3.2 ms20) of Ho3+ in ZBLAN glass, combined with large mode-area waveguides makes them promising candidates for high quality laser emission in mode-locking, single frequency, and Q-switching modes.

  • 99.
    Lebedova, Jana
    et al.
    Karolinska Inst, Inst Environm Med, Nobels Vag 13, S-17177 Stockholm, Sweden.;Masaryk Univ, RECETOX, Kamenice 753-5,Pavilon A29, CZ-62500 Brno, Czech Republic..
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Karlsson, Hanna L.
    Karolinska Inst, Inst Environm Med, Nobels Vag 13, S-17177 Stockholm, Sweden..
    Size-dependent genotoxicity of silver, gold and platinum nanoparticles studied using the mini-gel comet assay and micronucleus scoring with flow cytometry2018In: Mutagenesis, ISSN 0267-8357, E-ISSN 1464-3804, Vol. 33, no 1, p. 77-85Article in journal (Refereed)
    Abstract [en]

    Metallic nanoparticles (NPs) are promising nanomaterials used in different technological solutions as well as in consumer products. Silver (Ag), gold (Au) and platinum (Pt) represent three metallic NPs with current or suggested use in different applications. Pt is also used as vehicle exhaust catalyst leading to a possible exposure via inhalation. Despite their use, there is limited data on their genotoxic potential and possible size-dependent effects, particularly for Pt NPs. The aim of this study was to explore size-dependent genotoxicity of these NPs (5 and 50 nm) following exposure of human bronchial epithelial cells. We characterised the NPs and assessed the viability (Alamar blue assay), formation of DNA strand breaks (mini-gel comet assay) and induction of micronucleus (MN) analysed using flow cytometry (in vitro microflow kit). The results confirmed the primary size (5 and 50 nm) but showed agglomeration of all NPs in the serum free medium used. Slight reduced cell viability (tested up to 50 mu g/ml) was observed following exposure to the Ag NPs of both particle sizes as well as to the smallest (5 nm) Au NPs. Similarly, at non-cytotoxic concentrations, both 5 and 50 nm-sized Ag NPs, as well as 5 nm-sized Au NPs, increased DNA strand breaks whereas for Pt NPs only the 50 nm size caused a slight increase in DNA damage. No clear induction of MN was observed in any of the doses tested (up to 20 mu g/ml). Taken together, by using the comet assay our study shows DNA strand breaks induced by Ag NPs, without any obvious differences in size, whereas effects from Au and Pt NPs were size-dependent in the sense that the 5 nm-sized Au NPs and 50 nm-sized Pt NPs particles were active. No clear induction of MN was observed for the NPs.

  • 100. Lee, Jookyeong
    et al.
    Choi, Eun Jung
    Varga, Imre
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Yun, Sang-Ho
    Song, Changsik
    Terpyridine-functionalized stimuli-responsive microgels and their assembly through metal-ligand interactions2018In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 9, no 8, p. 1032-1039Article in journal (Refereed)
    Abstract [en]

    We developed a terpyridine-functionalized microgel (tpy-mG) for its supramolecular assembly. Tpy-mG was synthesized by amidation between 3-(4-([2,2':6',2 ''-terpyridin]-4'-yl)phenoxy) propan-1-amine and carboxylates of a thermo-responsive p(NIPAM-co-MAA) microgel (A-mG), which was synthesized by emulsion polymerization. After decorating terpyridine, its effects on the hydrodynamic radius, volume phase transition temperature (VPTT), and the colloidal stability of the microgel were investigated. Tpy-mG can be assembled reversibly with several metal ions (Ni2+, Fe2+, Co2+, or Zn2+), and interestingly the assembled tpy-mG-M2+ showed different rheological properties depending on the metal ion type; the weakly bound ions (Co2+, Zn2+) indicated fast dynamics for "inter-particular" exchange, resulting in much higher storage (G') and loss (G '') moduli. Photocatalysts such as Ru dyes can be easily introduced into tpy-mG via metal-ligand interactions, and the photooxidation of benzylamine was tested. The free Ru dye showed almost the same conversions at 25 and 50 degrees C, whereas the assembled Ru-tpy-mG-Mg2+ displayed reduced conversion at 50 degrees C (>VPTT). This is suggested to be due to the collapsed or "locked" structure around the photocatalytic center (Ru). Tpy-mG can be utilized as a good platform for developing responsive functional materials via reversible metal-ligand complexation.

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