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  • 101.
    Stålnacke, Emil
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Microstructure-corrosion interrelations in new low-lead and lead-free brass alloys2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In new low-lead and lead-free brass alloys, it is not understood how the corrosion properties,such as dezincification, are related to material composition as well as annealing temperatureand duration. This study aims to fill this knowledge gap by mapping sixteen annealingconditions and three different brass alloy compositions to their respective microstructure anddezincification performance. It was found that high dezincification depth was a result ofannealing temperatures at 300°C – 400°C, which promoted precipitation of intermetallicAlAs-particles along grain boundaries, twins and lead particles as well as precipitation of β-phase along grain boundaries. Their presence was correlated to high micro additions ofaluminium or iron in the material composition. An additional compositional factorcontributing to precipitation of high amount of β-phase was low copper/zinc-ratio.

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  • 102.
    Thormann, Esben
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Mizuno, Hiroyasu
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jansson, Kjell
    Stockholm Univ, Stockholm, Sweden.
    Hedin, Niklas
    Stockholm Univ, Stockholm, Sweden.
    Soledad Fernandez, M.
    Univ Chile, Santiago, Chile.
    Luis Arias, Jose
    Univ Chile, Santiago, Chile.
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pai, Ranjith Krishna
    Stockholm Univ, Stockholm, Sweden.
    Bergström, Lennart
    Stockholm Univ, Stockholm, Sweden.
    Embedded proteins and sacrificial bonds provide the strong adhesive properties of gastroliths2012In: Nanoscale, ISSN 2040-3364, Vol. 4, no 13, p. 3910-3916Article in journal (Refereed)
    Abstract [en]

    The adhesive properties of gastroliths from a freshwater crayfish (Cherax quadricarinatus) were quantified by colloidal probe atomic force microscopy (AFM) between heavily demineralized gastrolith microparticles and gastrolith substrates of different composition. Combined AFM and transmission electron microscopy studies demonstrated that the sequential detachment and large adhesion energies that characterise the adhesive behaviour of a native gastrolith substrate are dominated by sacrificial bonds between chitin fibres and between chitin fibres and CaCO3. The sacrificial bonds were shown to be strongly related to the gastrolith proteins and when the majority of these proteins were removed by ethylenediaminetetraacetic acid (EDTA), the sequential detachment disappeared and the adhesive energy was reduced by more than two orders of magnitude.

  • 103. Ulcinas, Arturas
    et al.
    Valdre, Giovanni
    Snitka, Valentinas
    Miles, Mervyn J.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Antognozzi, Massimo
    Shear Response of Nanoconfined Water on Muscovite Mica: Role of Cations2011In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 17, p. 10351-10355Article in journal (Refereed)
    Abstract [en]

    By monitoring the thermal noise of a vertically oriented micromechanical force sensor, we detect the viscoelastic response to shear for water in a subnanometer confinement. Measurements in pure water as well as under acidic and high-ionic-strength conditions relate this response to the effect of surface-adsorbed cations, which, because of their hydration, act as pinning centers restricting the mobility of the confined water molecules.

  • 104.
    Viklund, Peter
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pettersson, Rachel
    Outokumpu Stainless.
    HCl-induced high temperature corrosion of austenitic stainless steels under thermal cycling conditions and the effect of preoxidation2011In: Oxidation of Metals, ISSN 0030-770X, E-ISSN 1573-4889, Vol. 76, no 1/2, p. 111-126Article in journal (Refereed)
    Abstract [en]

    Gaseous HCl released during combustion is one reason for the severe materials degradation often encountered in power generation from waste and biomass. In this study, three stainless steels (the low alloyed EN 1.4982, the standard EN 1.4301 and the higher alloyed EN 1.4845) were tested by repeated thermal cycling in an environment comprising N2–10%O2–5%H2O–0.05%HCl at both 400 and 700 °C. The materials were exposed with ground surfaces and preoxidised at 400 or 700 °C. A positive effect of preoxidation is evident when alloys are exposed at 400 °C. Oxide layers formed during preoxidation effectively suppress chlorine ingress for all three materials, while chlorine accumulation at the metal/oxide interface is detected for surface ground specimens. The positive effect of preoxidation is lost at 700 °C and corrosion resistance is dependent on alloying level. At 700 °C metal chloride evaporation contributes significantly to the material degradation. Based on the results, high temperature corrosion in chlorinating environments is discussed in general terms.

  • 105.
    Wang, Xin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Protein Interactions with Metal Surfaces: Adsorption and Metal Release2015Doctoral thesis, comprehensive summary (Other academic)
  • 106.
    Wei, Zheng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Edin, Jonathan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Karlsson, Anna Emelie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Petrovic, Katarina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Soroka, Inna L.
    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.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Can gamma irradiation during radiotherapy influence the metal release process for biomedical CoCrMo and 316L alloys?2018In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 106, no 7, p. 2673-2680Article in journal (Refereed)
    Abstract [en]

    The extent of metal release from implant materials that are irradiated during radiotherapy may be influenced by irradiation-formed radicals. The influence of gamma irradiation, with a total dose of relevance for radiotherapy (e.g., for cancer treatments) on the extent of metal release from biomedical stainless steel AISI 316L and a cobalt-chromium alloy (CoCrMo) was investigated in physiological relevant solutions (phosphate buffered saline with and without 10 g/L bovine serum albumin) at pH 7.3. Directly after irradiation, the released amounts of metals were significantly higher for irradiated CoCrMo as compared to nonirradiated CoCrMo, resulting in an increased surface passivation (enhanced passive conditions) that hindered further release. A similar effect was observed for 316L showing lower nickel release after 1 h of initially irradiated samples as compared to nonirradiated samples. However, the effect of irradiation (total dose of 16.5 Gy) on metal release and surface oxide composition and thickness was generally small. Most metals were released initially (within seconds) upon immersion from CoCrMo but not from 316L. Albumin induced an increased amount of released metals from AISI 316L but not from CoCrMo. Albumin was not found to aggregate to any greater extent either upon gamma irradiation or in the presence of trace metal ions, as determined using different light scattering techniques. Further studies should elucidate the effect of repeated friction and fractionated low irradiation doses on the short- and long term metal release process of biomedical materials.

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  • 107.
    Wojas, Natalia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, Box 5607, SE-11486 Stockholm, Sweden.
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, Box 5607, SE-11486 Stockholm, Sweden.
    Wallqvist, Viveca
    RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, Box 5607, SE-11486 Stockholm, Sweden..
    Jarn, Mikael
    RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, Box 5607, SE-11486 Stockholm, Sweden..
    Schoelkop, Joachim
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland..
    Gane, Patrick A. C.
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland.;Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, POB 16300, FI-00076 Aalto, Finland..
    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 Surface Proc & Formulat, Box 5607, SE-11486 Stockholm, Sweden.
    Iceland spar calcite: Humidity and time effects on surface properties and their reversibility2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 541, p. 42-55Article in journal (Refereed)
    Abstract [en]

    Understanding the complex and dynamic nature of calcite surfaces under ambient conditions is important for optimizing industrial applications. It is essential to identify processes, their reversibility, and the relevant properties of CaCO3 solid-liquid and solid-gas interfaces under different environmental conditions, such as at increased relative humidity (RH). This work elucidates changes in surface properties on freshly cleaved calcite (topography, wettability and surface forces) as a function of time (<= 28 h) at controlled humidity (<= 3-95 %RH) and temperature (25.5 degrees C), evaluated with atomic force microscopy (AFM) and contact angle techniques. In the presence of humidity, the wettability decreased, liquid water capillary forces dominated over van der Waals forces, and surface domains, such as hillocks, height about 7.0 angstrom, and trenches, depth about -3.5 angstrom, appeared and grew primarily in lateral dimensions. Hillocks demonstrated lower adhesion and higher deformation in AFM experiments. We propose that the growing surface domains were formed by ion dissolution and diffusion followed by formation of hydrated salt of CaCO3. Upon drying, the height of the hillocks decreased by about 50% suggesting their alteration into dehydrated or less hydrated CaCO3. However, the process was not entirely reversible and crystallization of new domains continued at a reduced rate.

  • 108.
    Xiang, Shengmei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jonsson, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Zhu, Baohua
    Scania CV AB, SE-15187 Sodertalje, Sweden..
    Odqvist, Joakim
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Corrosion fatigue of austenitic cast iron Ni-Resist D5S and austenitic cast steel HK30 in argon and synthetic diesel exhaust at 800 degrees C2020In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 132, article id 105396Article in journal (Refereed)
    Abstract [en]

    To increase the understanding of the corrosion-fatigue mechanisms in two cast iron-alloys used in exhaust manifolds, low-cycle fatigue tests at 800 degrees C in argon and synthetic diesel exhaust as well as isothermal oxidation tests in the exhaust atmosphere are conducted. The corrosion impacts on the fatigue life of the materials are quantitatively evaluated from comparing the G-N curves, and examined from characterization through SEM, EDX, EBSD and EPMA. The materials show very different behaviors to the synergistic effect of corrosion and fatigue. Different theories have been suggested based on the findings.

  • 109.
    Yin, Litao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing.
    FEM Modelling of Micro-galvanic Corrosion in Al Alloys Induced by Intermetallic Particles: Exploration of Chemical and Geometrical Effects2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Localized corrosion, such as pitting, crevice corrosion or galvanic corrosion, is a long-standing phenomenon that can greatly limit the life of metallic materials. For decades experimental methods have been used to try to understand the underlying physical, chemical and electrochemical processes that control localized corrosion in order to find effective protection methods against its propagation. The complexity of the phenomenon and its small geometric size have often severely restricted the basic understanding of local corrosion. In recent decades, computational methods have been developed as an alternative to the experimental methods. Compared to experimental methods, modeling and numerical simulation enable complicated systems to be systematically investigated without considering the inherent constraints of experimental methods.

        In the current Doctoral thesis, advanced calculation methodology has been used to study galvanic corrosion of an aluminum alloy with geometric resolution at micrometer level. The computational platform has been a commercial FEM-based software, COMSOL Multiphysics, which was combined with another software, Matlab. The current model system consists of a semi-spherical intermetallic particle, surrounded by a pure aluminum matrix. The aluminum surface is covered by an inert passive film, except for a ring-shaped surface around the particle itself. By assuming that the particle is electrochemically more noble than aluminum, it acts as a cathode and the surrounding aluminum ring as anode. By utilizing the FEM-based software, it has been possible to incorporate important physicochemical reactions, including the electrochemical anode and cathode reactions of the individual phases, mass transport of various chemical compounds formed during ongoing electrochemistry, homogeneous reactions in the electrolyte, as well as deposition of corrosion products consisting of Al(OH)3 along parts of the anodic area.

        What has made this study a significant step forward is that not only chemical changes but also geometrical changes have been taken into consideration in the simulation of ongoing micro-galvanic corrosion. Particularly challenging has been to mathematically master the gradual deposition of compact Al(OH)3 on an aluminum surface which gradually dissolves anodically. In the initial modeling work, the deposition of Al(OH)3 was assumed to occur only on the electrode surface, resulting in a gradual blockage of surface activity. In an even more advanced stage, the modeling has also sought to simulate the effect of a deposited porous film of Al(OH)3, formed through homogeneous reactions in the electrolyte. By taking into account inhibited diffusion and migration of chemical products that the porous film causes, its sterically inhibiting effect has for the first time been quantitatively interpreted. The porous corrosion product can most closely resemble the lid experimentally observed above local corrosion attacks, which leads to an even more diminished surface activity in electrochemical reactions compared with the deposition of only compact corrosion products on the anode surface.

        The kinetic model has resulted in a significantly deeper insight into the mechanism of micro-galvanic corrosion of the investigated system. The simulation has been shown to predict the time-dependent geometric changes of the anodically dissolved aluminum surface as well as the flow and distribution of generated chemical products. Contrary to the widely accepted perception that Al(OH)3 is not stable in the occluded acidified electrolyte environment, the calculations predict a higher local pH in the occluded electrolyte. This means that insoluble Al(OH)3 can be deposited on the electrode surface, the blocking effect of which may lead to a termination of the micro-galvanic corrosion. If the ring width is initially 0.5 μm or less, transport of OH- ions from the cathode surface to the occluded electrolyte environment is limited, leading to a local acidification within the occluded dissolving volume. At a given anodic ring width, an increased radius of the cathodic particle instead leads to an increased anodic dissolution rate by formation of a larger area for the cathode reaction. Variation of the chemical parameters in the electrolyte also shows that the simulated micro-galvanic corrosion rate of aluminum has a minimum at pH = 6. Both more acidic and more alkaline conditions result in an elevated anodic dissolution of aluminum. When pH ≤ 4, the deposition of Al(OH)3  becomes negligible, and the micro-galvanic corrosion will continue uninterrupted, completely in accordance with experimental data.

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    Thesis_Litao Yin
  • 110.
    Yin, Litao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing, China.
    Jin, Ying
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Numerical Simulation of Micro-Galvanic Corrosion of Al Alloys: Effect of Chemical Factors2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 13, p. C768-C778Article in journal (Refereed)
    Abstract [en]

    A finite element model for simulating the propagation of micro-galvanic corrosion of Al alloys induced by intermetallic particle was established to reveal the dynamic changes including a moving dissolution boundary, deposition of reaction products and their blocking effect. This model has previously been used to study the influence of geometrical factors such as the particle size and width of the anodic ring. In this work, we explore effects of chemical factors including pH and bulk concentration of O-2 by using chemical-dependent electrochemical kinetics as input parameters. The simulations reveal that the micro-galvanic corrosion rate is slowest at pH = 6. For pH > 6, the rise of pH increases the dissolution rate of Al and also the deposition rate of Al(OH)(3), leading to a faster but more short localized Al dissolution. For pH < 6, the decline of pH accelerates Al dissolution and inhibits Al(OH)(3) deposition, leading to a faster and more long lasting Al dissolution. At pH <= 4, deposition of Al(OH)(3) becomes negligible, and localized corrosion will propagate continuously. Within the O-2 concentration range relevant for atmospheric conditions, a lower O-2 concentration in the solution leads to a slower rate of micro-galvanic corrosion.

  • 111.
    Yin, Litao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, 30 Xueyuan Rd, Beijing 100083, Peoples R China.;KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Div Surface & Corros Sci, Drottning Kristinas Vag 51, SE-10044 Stockholm, Sweden..
    Li, Wenchao
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, 30 Xueyuan Rd, Beijing 100083, Peoples R China..
    Wang, Yongchao
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, 30 Xueyuan Rd, Beijing 100083, Peoples R China..
    Jin, Ying
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, 30 Xueyuan Rd, Beijing 100083, Peoples R China..
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Numerical simulation of micro-galvanic corrosion of Al alloys: Effect of density of Al(OH)(3) precipitate2019In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 324, article id UNSP 134847Article in journal (Refereed)
    Abstract [en]

    This work is a further step to develop a finite element model to simulate localized corrosion of aluminum alloys driven by micro-galvanic effects. The focus herein is to explore the effect of density (porosity and tortuosity) of Al(OH)(3) precipitates generated both on the electrode surface and in the liquid phase. Two coupled processes are identified and discussed, both influencing the local pH: the Al3+ dissolution from the electrode surface, and the steric hindrance effects on mass transport of species between the bulk solution and the anolyte next to the corroding surface. With the densest precipitate investigated, Al3+ dissolution is more effectively blocked and the mass transport largely hindered of Al3+ ions leaving the electrode surface. With increasing porosity of the precipitate, Al3+ dissolution is enhanced, also the mass transport of species in the electrolyte. The most severe localized acidification inside the occluded volume occurs when the density, namely ascribed by porosity, of precipitate is at an intermediate level with epsilon(c )= 0.01. In qualitative agreement with experimental observations, this work highlights the importance of corrosion product density on the progress of localized corrosion.

  • 112.
    Zhang, Fan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Brandner, Birgit
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    In situ confocal Raman micro-spectroscopy and electrochemical studies of mussel adhesive protein and ceria composite film on carbon steel in salt solutions2013In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 107, p. 276-291Article in journal (Refereed)
    Abstract [en]

    Thin films composed of Mefp-1 and ceria nanoparticles have shown an increasing corrosion inhibition effect with time for carbon steel in acidic aqueous solutions containing phosphate, which motivates a detailed study of the inhibition mechanism by in situ confocal Raman micro-spectroscopy (CRM) and electrochemical impedance spectroscopy (EIS) measurements. The presence of both CeO2 and ferric oxides in the thin composite film was demonstrated by X-ray photoelectron spectroscopy analysis. The Raman spectra assisted by DFT calculations suggest that Mefp-1 forms tri-Fe3+/Mefp-1 complexes and binds to ceria nanoparticles in the composite film. The in situ CRM measurement allow us to follow the development of corrosion products. The measurements show a mixture of Fe oxides/oxyhydroxides, and also indicate that ferrous oxides may be further oxidized by the composite film. Moreover, phosphate ions react with the Fe ions released from the surface to form iron-phosphate deposits, which become incorporated into the corrosion product layer and the composite film. The EIS measurements suggest a layered surface structure formed by the initial Mefp-1/ceria composite layer and the corrosion products/iron-phosphate deposits. These measurements also demonstrate the greatly increased inhibition effect of the composite film in the presence of the phosphate ions. The consistent CRM and EIS results suggest that the iron-phosphate deposits heal defects in the composite film and corrosion product layer, which results in a significantly improved corrosion inhibition of the Mefp-1/ceria composite film during initial and long term exposure.

  • 113.
    Zhang, Fan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chen, Chengdong
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hou, R.
    Li, Jing
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Cao, Yanhui
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dong, S.
    Lin, C.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Investigation and application of mussel adhesive protein nanocomposite film-forming inhibitor for reinforced concrete engineering2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 153, p. 333-340Article in journal (Refereed)
    Abstract [en]

    A mussel adhesive protein based nanocomposite thin film was produced to be applied as surface pre-treatment or primer on rebars of reinforced concrete. The film deposition and drying processes were investigated to enhance the corrosion protection, and facilitate large-scale industrial applications. The morphology, chemical composition and microstructure of the film were characterised with SEM, EDS, Micro-IR and AFM techniques. EIS results suggested the film provides excellent and increased corrosion protection for the carbon steel in mild and extreme concrete pore solutions. In-situ AFM results demonstrated the self-healing ability of the film to the pitting corrosion.

  • 114.
    Zhang, Xian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Liu, Xiaoyan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The protective role of hydrozincite during initial corrosion of a Cu40Zn alloy in chloride-containing laboratory atmosphere2016In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 103, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Hydrozincite, Zn-5(CO3)(2)(OH)(6), was recently found to play a key role in reducing corrosion product flaking on Cu-Zn alloys. A fundamental study was undertaken to explore the underlying mechanisms, in particular why hydrozincite can suppress the interaction between chlorides and the alloy surface. Hydrozincite could be formed by exposure of Cu40Zn to air at 70% relative humidity and 1000 ppm of CO2 resulting in a surface of decreased wettability. Its presence reduces the initial spreading ability of NaCl-containing droplets and lowers the overall initial corrosion rate when the alloy is exposed to pre-deposited NaCl and wet/dry cycles.

  • 115.
    Zhang, Xian
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Wuhan Univ Sci & Technol, State Key Lab Refractory Mat & Met, Hubei Prov Key Lab Syst Sci Met Proc, Int Res Inst Steel Technol, Wuhan 430081, Hubei, Peoples R China..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment2018In: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 34, no 9, p. 641-648Article in journal (Refereed)
    Abstract [en]

    Accelerated NVDA (VDA 233-102) tests were performed on bare Zn and Al sheets, Galfan coating (Zn-5 wt-% Al) and Galvalume coating (Zn-55 wt-% Al) on steel. ZnO, Zn(OH)(2) and Zn-5(OH)(8)Cl-2 center dot H2O were the main corrosion products identified on both bare Zn sheet and Galfan. AlOOH and Al(OH)(3) were preferentially formed on bare Al sheet and Galvalume. In addition, Zn-Al-containing corrosion products, Zn6Al2(OH)(16)CO3 center dot 4H(2)O and/or Zn2Al(OH)(6)Cl center dot 2H(2)O were identified on both Galfan and Galvalume. Corrosion products of Zn6Al2(OH)(16)CO3 center dot 4H(2)O with a platelet morphology were preferentially formed in the zinc-rich interdendritic regions of the Galvalume surface. Galfan revealed a similar corrosion behaviour as bare Zn sheet, whereas Galvalume exhibited similar behaviour as bare Al sheet. Deposition of chlorides highly influenced the corrosion of both Galvalume and Al rather than Galfan and Zn due to the rapid local damage of the compact native thin film of Al2O3.

  • 116.
    Zhao, Weijie
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Corrosion initiation induced by sodium sulfate and sodium chloride particles on Cu and the golden alloy Cu5Al5Zn at simulated atmospheric conditions2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Effects of sodium sulfate (Na2SO4) particle deposition on the atmospheric corrosion of copper (Cu) metal and a Cu-based alloy (Cu5Al5Zn) used in architectural applications were investigated at laboratory conditions compared with effects induced by sodium chloride (NaCl) and to some extent ammonium sulfate (NH4)2SO4 induced corrosion. Pre-deposited surfaces were exposed to repeated wet/dry conditions in a climatic chamber and the formation of corrosion products were assessed using light optical microscopy (LOM), scanning electron microscopy with elemental analysis (SEM/EDS), Fourier transform infrared techniques (FTIR microscopy) and cathodic reduction (CR). Na2SO4 induced corrosion resulted in corrosion cells locally over the surface on both Cu and Cu5Al5Zn, of increased oxygen content in the anodic area of the cells (center of pre-deposited area). The main corrosion products formed on Cu metal are basic copper sulfates and cuprite (Cu2O), while basic sulfates (copper and/or zinc) and Cu2O were the main corrosion products formed on Cu5Al5Zn. A combined deposition of Na2SO4 + NaCl was carried out on the Cu5Al5Zn alloy using two different deposition methods to investigate the possible interplay from a corrosion initiation perspective between the two salt particles. For short time exposed Cu5Al5Zn (1 cycle), two different corrosion cells formed, mainly induced by Na2SO4 and NaCl. Corrosion products formed in anodic areas of a Na2SO4 induced corrosion cell were similar to findings observed for Cu5Al5Zn pre-deposited with Na2SO4 only, whereas peripheral cathodic areas primarily were affected by NaCl dissolution and predominantly composed of Cu2O that was the main corrosion product with small amount of hydroxides and carbonates of the NaCl induced corrosion cells. After relatively longer exposure periods (2 and 6 wet/dry cycles), NaCl dominated the corrosion of the entire surface with the formation of more Cu2O, hydroxides and carbonates. Cathodic reduction findings revealed a negative interplay on corrosion for the mixed salt after short time exposures (1 and 2 cycles), whereas a slight synergistic effect was evident after a longer exposure period (6 cycles), compared with corrosion induced by single salts.

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  • 117.
    Zhao, Weijie
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nano Infrared Microscopy: Obtaining Chemical Information on the Nanoscale in Corrosion Studies2019In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, no 11, p. C3456-C3460Article in journal (Refereed)
    Abstract [en]

    In this perspective article, the novel technique "nano infrared microscopy" is introduced as a valuable tool in the field of corrosion science to obtain chemical information with a spatial resolution of around 10 nm. Accordingly, the resolution is well below the diffraction limit, in contrast to conventional vibrational microscopy techniques. Thus, studies of corrosion initiation, localized corrosion, and thin protective films can be performed in greater detail than before. There are a few different types of nano infrared microscopes, but they all have in common that they are based on a combination of infrared (IR) spectroscopy and atomic force microscopy (AFM). In this article the theory of the different techniques is discussed, and some results are highlighted to show the ability of the technique in the field of corrosion science. Future possibilities of the technique in studies of corrosion and degradation of materials are also discussed. 

  • 118.
    Zheng, Wei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH.
    The effect of albumin and fibrinogen on the corrosion and metal release from a biomedical CoCrMo alloy2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Corrosion and metal release mechanisms of CoCrMo alloys are at human biological conditions not fully understood. The main objective of this master thesis was to investigate whether the Vroman effect influences the extent of metal release from CoCrMo alloy in mixed protein solutions. The project focuses on the corrosion properties and release of cobalt (Co), chromium (Cr) and molybdenum (Mo) from a CoCrMo alloy into simulated physiological solutions of pH 7.2-7.4 in the presence of proteins.

    The metal release study was performed in phosphate buffered saline (PBS) for 4 and 24 h at 37 °C with and without different concentration of proteins (bovine serum albumin-BSA and fibrinogen-Fbn from bovine plasma). In order to investigate whether any Vroman effect could affect the extent of released metals in solutions, sequential tests were performed by sampling after 1, 4, 6 and 24 h in solutions that were partially replenished after 5 h. Significant metal-induced protein aggregation and precipitation were observed in solutions of physiologically-relevant protein concentrations (40 g/L BSA and 2.67 g/L Fbn). Cr was strongly enriched in the surface oxide of CoCrMo after exposure in all solutions. This was for all solutions accompanied by metal release processes dominated by Co. Based on electrochemical investigations, the electrochemical activity did not increase, but rather decreased, in protein-containing solutions as compared to PBS alone. This could possibly be explained by blocking of cathodic areas as a result of protein adsorption. 

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  • 119.
    Zhou, Nian
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Influence of grinding operations on surface integrity and chloride induced stress corrosion cracking of stainless steels2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stainless steels were developed in the early 20th century and are used where both the mechanical properties of steels and corrosion resistance are required. There is continuous research to allow stainless steel components to be produced in a more economical way and be used in more harsh environments. A necessary component in this effort is to correlate the service performance with the production processes.

    The central theme of this thesis is the mechanical grinding process.  This is commonly used for producing stainless steel components, and results in varied surface properties that will strongly affect their service life. The influence of grinding parameters including abrasive grit size, machine power and grinding lubricant were studied for 304L austenitic stainless steel (Paper II) and 2304 duplex stainless steel (Paper I). Surface integrity was proved to vary significantly with different grinding parameters. Abrasive grit size was found to have the largest influence. Surface defects (deep grooves, smearing, adhesive/cold welding chips and indentations), a highly deformed surface layer up to a few microns in thickness and the generation of high level tensile residual stresses in the surface layer along the grinding direction were observed as the main types of damage when grinding stainless steels. A large degree of residual stress anisotropy is interpreted as being due to mechanical effects dominating over thermal effects.

    The effect of grinding on stress corrosion cracking behaviour of 304L austenitic stainless steel in a chloride environment was also investigated (Paper III). Depending on the surface conditions, the actual loading by four-point bend was found to deviate from the calculated value using the formula according to ASTM G39 by different amounts. Grinding-induced surface tensile residual stress was suggested as the main factor to cause micro-cracks initiation on the ground surfaces. Grinding along the loading direction was proved to increase the susceptibility to chloride-induced SCC, while grinding perpendicular to the loading direction improved SCC resistance.

    The knowledge obtained from this work can provide a reference for choosing appropriate grinding parameters when fabricating stainless steel components; and can also be used to help understanding the failure mechanism of ground stainless steel components during service.

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    Thesis
  • 120.
    Álvarez Asencio, Rubén
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sababi, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ejnermark, Sebastian
    Ekman, Lars
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Tech Res Inst Sweden, Sweden.
    Role of microstructure on corrosion initiation of an experimental tool alloy: A Quantitative Nanomechanical Property Mapping study2014In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 89, p. 236-241Article in journal (Refereed)
    Abstract [en]

    The adhesion properties of a FeCrVN experimental tool alloy immersed in pure water and sodium chloride solution have been studied by Quantitative Nanomechanical Property Mapping to understand the influence of microstructure on corrosion initiation of this alloy. The approach used here allows early observation and identification of pre-pitting events that may lead to passivity breakdown of the alloy. Adhesion provides a good distinction between the different regions and we ascribe this to their vanadium and nitrogen contents. Finally, the prepitting is characterized by generation of small particles in specific regions of the surface with low chromium content.

  • 121.
    Örnek, Cem
    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, Drottning Kristinas Vag 51, S-10044 Stockholm, Sweden..
    Stress Corrosion Cracking and Hydrogen Embrittlement of Type 316L Austenitic Stainless Steel Beneath MgCl2 and MgCl2: FeCl3 Droplets2019In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 75, no 6, p. 657-667Article in journal (Refereed)
    Abstract [en]

    The atmospheric corrosion, as well as environmentally assisted cracking behavior of 316L austenitic stainless steel (UNS S31603) beneath MgCl2 and MgCl2: FeCl3 droplets under elastic and elastic-plastic strain exposed for 6 months at 50 degrees C and 30% relative humidity were investigated. Shallow and deep corrosion sites with filiform corrosion along with stress corrosion cracking (SCC) were formed beneath the salt-laden droplets, and the potential role of hydrogen embrittlement (HE) and crevice corrosion in damage evolution elucidated. Elastic strain (0.1%) was sufficient to cause SCC cracking as well as HE under droplets with 145 mu g/cmth> of chloride, with the severity of cracking increasing with increasing chloride deposition density (CDD). Elastic-plastic strain (0.2%) increased the propensity to both corrosion and SCC/HE, with cracks seen under droplets having CDD as low as 14.5 mu g/cm(2). Elastic-plastic strain was further seen to facilitate and accelerate pitting corrosion, leading to pits with more penetration depth. The extent of corrosion and cracking increases with increasing chloride deposition density, with ferric ions having more severe effect, in particular promoting localized corrosion with multiple nucleation sites. The work reported here was brought into a larger context of stainless steel corrosion and discussed in light of better understanding atmospheric corrosion of structural components such as nuclear waste storage containers.

  • 122.
    Örnek, Cem
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christopher
    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.
    Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements2019In: npJ Materials Degradation, ISSN 2397-2106, Vol. 3, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    The characterisation of passive oxide films on heterogeneous microstructures is needed to assess local degradation (corrosion, cracking) in aggressive environments. The Volta potential is a surface-sensitive parameter which can be used to assess the surface nobility and hence passive films. In this work, it is shown that the Volta potential, measured on super duplex stainless steel by scanning Kelvin probe force microscopy, correlates with the electrochemical properties of the passive film, measured by electrochemical impedance spectroscopy and potentiodynamic polarisation. Natural oxidation by ageing in ambient air as well as artificial oxidation by immersion in concentrated nitric acid improved the nobility, both reflected by increased Volta potentials and electrochemical parameters. Passivation was associated with vanishing of the inherent Volta potential difference between the ferrite and austenite, thereby reducing the galvanic coupling and hence improving the corrosion resistance of the material. Hydrogen-passive film interactions, triggered by cathodic polarisation, however, largely increased the Volta potential difference between the phases, resulting in loss of electrochemical nobility, with the ferrite being more affected than the austenite. A correlative approach of using the Volta potential in conjunction with electrochemical data has been introduced to characterise the nobility of passive films in global and local scale.

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  • 123.
    Örnek, Cem
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Långberg, Marie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Evertsson, Jonas
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Harlow, Gary
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Linpe, Weronica
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Rullik, Lisa
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Carla, Francesco
    European Synchrotron Radiat Facil, F-38000 Grenoble, France..
    Felici, Roberto
    Area Ric Roma 2 Tor Vergata, SPINCNR, I-00133 Rome, Italy..
    Bettini, Eleonora
    Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Kivisakk, Ulf
    Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Lundgren, Edvin
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Pan, Jinshan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    In-situ synchrotron GIXRD study of passive film evolution on duplex stainless steel in corrosive environment2018In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 141, p. 18-21Article in journal (Refereed)
    Abstract [en]

    This paper presents new findings about the passive film formed on super duplex stainless steel in ambient air and corrosive environments, studied by synchrotron grazing-incidence X-ray diffraction (GIXRD). The passive film, formed in air, was seen to be a nano-crystalline mixed-oxide. Electrochemical polarisation to the passive region in aqueous 1 M NaCl at room temperature resulted in an increase of the passive film thickness, preferential dissolution of Fe, and partial loss of crystallinity. After termination of polarization to the transpassive regime, reformation of the mixed-oxides was observed, showing a thicker, semi-crystalline, and more defective nature (more vacancies) with further new oxides/hydroxides.

  • 124.
    Örnek, Cem
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. University of Manchester, UK.
    Walton, J.
    Hashimoto, T.
    Ladwein, T. L.
    Lyon, S. B.
    Engelberg, D. L.
    Characterization of 475 degrees C Embrittlement of Duplex Stainless Steel Microstructure via Scanning Kelvin Probe Force Microscopy and Magnetic Force Microscopy2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 6, p. C207-C217Article in journal (Refereed)
    Abstract [en]

    Scanning Kelvin probe force microscopy (SKPFM) measured local Volta potentials in microstructure of 22Cr-5Ni duplex stainless steel have been correlated to microstructure development with aging treatments at 475 degrees C. Magnetic force microscopy (MFM) was employed to differentiate crystallographic phases to provide complementary information. The absolute Volta potentials of both ferrite and austenite increased after 5 hours of aging, indicating electrochemical ennoblement of the entire microstructure. Longer aging resulted in a gradual decrease of measured Volta potentials in both phases. The microstructure showed after 255 hours aging up to 2.5-times larger potential differences than in the as-received condition, indicating impaired electrochemical nobility. In the as-received microstructure, the ferrite phase was less noble than the austenite, whereas after 5 hours aging both phases had similar, balanced Volta potentials which indicated a balanced nobility of ferrite and austenite. Longer aging treatment caused severe loss of nobility for the entiremicrostructure, with ferrite showing larger changes in Volta potential than the austenite. Spinodal microstructure decomposition and associated phase reactions of the ferrite, with elemental redistribution in the austenite, are the reason for the observed changes in microstructure nobility.

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