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  • 51.
    Hedberg, Yolanda S.
    et al.
    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.
    Metal release from stainless steel in biological environments: A review2016In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 11, no 1, article id 018901Article, review/survey (Refereed)
    Abstract [en]

    Due to its beneficial corrosion resistance, stainless steel is widely used in, e.g., biomedical applications, as surfaces in food contact, and for products intended to come into skin contact. Low levels of metals can be released from the stainless steel surface into solution, even for these highly corrosion resistant alloys. This needs to be considered in risk assessment and management. This review aims to compile the different metal release mechanisms that are relevant for stainless steel when used in different biological settings. These mechanisms include corrosion-induced metal release, dissolution of the surface oxide, friction-induced metal release, and their combinations. The influence of important physicochemical surface properties, different organic species and proteins in solution, and of biofilm formation on corrosion-induced metal release is discussed. Chemical and electrochemical dissolution mechanisms of the surface oxides of stainless steel are presented with a focus on protonation, complexation/ligand-induced dissolution, and reductive dissolution by applying a perspective on surface adsorption of complexing or reducing ligands and proteins. The influence of alloy composition, microstructure, route of manufacture, and surface finish on the metal release process is furthermore discussed as well as the chemical speciation of released metals. Typical metal release patterns are summarized.

  • 52.
    Henderson, Pamela
    Vattenfall research and Development.
    Högtemperaturkorrosion i barkpannor: Del 12007In: Nordisk Papper & Massa, ISSN 1652-9995, no 2, p. 58-59Article, review/survey (Other (popular science, discussion, etc.))
    Abstract [sv]

    Ökad eldning av retur- och avfallsbränslen i barkpannor har medfört att alltfler har fått problem med avlagringar och korrosion. Det finns ett stort intresse att minska kostnader för högtemperaturkorrosion genom att förlänga livslängden och att minska risken för oplanerade stopp. Samtidigt finns det starka drivkrafter att förbättra anläggningarnas elverkningsgrad genom högre ångdata.

  • 53.
    Henderson, Pamela
    Vattenfall Research and Development.
    Högtemperaturkorrosion i barkpannor: del 22007In: Nordisk Papper & Massa, ISSN 1652-9995, no 3/4, p. 83-85Article, review/survey (Other (popular science, discussion, etc.))
    Abstract [sv]

    Ökad eldning av retur- och avfallsbränslen i barkpannor har medfört att alltfler har fått problem med avlagringar och korrosion. Det finns ett stort intresse att minska kostnader för högtemperaturkorrosion genom att förlänga livslängden och att minska risken för oplanerade stopp. Samtidigt finns det starka drivkrafter att förbättra anläggningarnas elverkningsgrad genom högre ångdata.

  • 54.
    Henderson, Pamela
    et al.
    Vattenfall Research and Development.
    Andersson, Christer
    Vattenfall Research and Development.
    Szakalos, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kassman, Håkan
    Vattenfall Research and Development.
    Högberg, Jan
    Pettersson, Rachel
    Reducing superheater corrosion in wood-fired boilers2008In: Novel approaches to improving high temperature corrosion resistance: European Federation of Corrosion Publications number 47 / [ed] M Schütze and W.J. Quadakkers, Woodhead Publishing Limited, 2008, p. 428-444Chapter in book (Refereed)
    Abstract [en]

    In the last few years, there has been a move away from burning fossil fuels through the co-utilisation of biomass and coal and finally to 100% biomass such as wood and waste wood products. Unfortunately, burning of biomass causes widespread fouling of superheater tubes and corrosion can occur rapidly under the sticky alkali chloride deposits. Even at today's maximum steam temperatures of 500 to540°C there are some severe corrosion problems when burning  100% wood-based fuel. It is also desirable to be able to burn other environmental fuels such as straw, demolition wood or other wood-waste products, to reduce production costs and avoid dumping waste at landfill sites. This, however, makes the corrosion and fouling problems even more serious. 

     A complete set of superheaters for a 100 MW combined heat and power boiler costs in excess of 1 MEuro. The durability of superheaters is thus an important factor in determining the long-term production costs. Unplanned outages due to leaking superheaters are also very expensive. As well as causing corrosion problems, the build-up of deposits reduces the heat uptake to the superheaters which leads to lower efficiency. Consequently, ways are being sought to reduce superheater corrosion.

    Most biomass fuels have a high content of alkali metals and chlorine, but they contain very little sulphur compared to fossil fuels. Potassium chloride, KCl, is found in the gas phase, condenses on the superheater tubes and forms complex alkali salts with iron and other elements in the steels. These salts have low melting points and are very corrosive. Vattenfall has developed and patented an instrument for in-situ measurement of gaseous alkali chlorides which gives an indication of how corrosive the flue gases are.  This instrument is called an in-situ alkali chloride monitor (IACM).  Vattenfall has also developed and patented a concept with a sulphate containing compound called “ChlorOut” , which is sprayed into the flue gases after combustion is complete, but before the flue gases reach the superheaters, and effectively converts KCl into potassium sulphate, K2SO4.  This compound much less corrosive than KCl.  In the experiments reported here the sulphate used in ChlorOut was ammonium sulphate. This is also used for the reduction of NOx.

     This study reports on measures taken to reduce superheater corrosion in two fluidised bed boilers burning wood-based fuels, using the ChlorOut additive to control the KCl levels and by using more corrosion-resistant steels.

  • 55.
    Henderson, Pamela
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Davis, Colin
    Montgomery, Melanie
    Karlsson, Asger
    In-situ fireside corrosion testing of superheater materials with coal, wood and straw fuels for conventional and asvanced steam temperatures2005In: VGB PowerTech, ISSN 1435-3199, Vol. 84, no 6, p. 53-59Article in journal (Refereed)
    Abstract [en]

    An increase in the steam temperature of a power station increases the electrical efficiency of the turbine. This in turn leads to a reduction in the cost of electricity and in environmental emissions produced per unit of electricity generated. However, higher steam temperatures give rise to more aggressive corrosive environments and the choice of material becomes more important. In addition, the aggressiveness of the fuels also depends on their chemical compositions.  As part of a European research programme (COST 522) fireside corrosion tests of superheater and waterwall materials have been performed in-situ in industrial boilers or combustion test facilities, simulating conventional and higher steam temperatures. The fuels used were, straw, wood (logging residues) and coal. Goals were  set at different maximum steam temperatures and lifetimes according to the fuel. The targets were: coal 650°C/100,000 h,  wood 580°C/40,000 h and straw 580°C/20,000 h .A wide range of materials was tested.  An overriding constraint was that the materials must be economically viable and not impose exceptional fabrication requirements. Some materials were tested in a number of combustion environments, allowing useful comparisons to be made. The results showed that for a given superheater alloy, temperature and fuel, the corrosion rate depended on the alloy’s position in a superheater bank. Tubes on the outside, exposed to the flue gas, corroded faster than those positioned deeper in a bank.  Tubes experiencing a greater heat flux will corrode more rapidly. Poorly controlled combustion will also increase corrosion. Straw was much more corrosive than wood (logging residues). The difference in corrosiveness increased with increasing temperature above a metal temperature of about 520°C. The corrosion rates of the alloys tested during wood-firing were only a little higher than those from firing coal with a medium to high chlorine content. Straw and wood are often collectively known as “biomass”, but the corrosion they cause can vary by a factor of 5 or more. No difference could be found in the fireside  corrosion rates of the steels TP 347H and TP 347HFG, when tested under similar conditions. Esshete 1250 also showed similar fireside corrosion rates to347 instraw and wood boilers and at temperatures below 650°Cin coal boilers.

    Several alloys were identified to resist corrosion in coal-fired plant at metal temperatures of680°C(steam temperatures650°C) and high heat fluxes.  Adequate high temperature creep strength remains more problematic.  At lower heat fluxes (resulting in lower corrosion rates) more candidate alloys exist.

    It is expected that the goals set can be achieved with the use of suitable alloys in the case of wood, waste and coal. For wood (logging residues) TP347, Esshete 1250 and 50Ni50Cr coatings showed sufficient corrosion resistance at the target temperatures. In the coal case  HR3C fulfills the requirements of strength and corrosion resistance with a high heat flux and  Super 304H and SAVE 25 if the heat flux is low. HR11N and IN671 are suitable for use as claddings on a substrate with the appropriate creep strength. The goal set for straw firing was ambitious, a steam temperature of580°C, and in this case a combination of material, combustion technology and boiler design are needed.

  • 56.
    Henderson, Pamela
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kassman, Håkan
    Andersson, Christer
    The use of fuel additives in wood and waste wood fired boilers to reduce corrosion and fouling problems2004In: VGB PowerTech, ISSN 1435-3199, Vol. 84, no 6, p. 58-62Article in journal (Refereed)
    Abstract [en]

    One of the major drawbacks to the implementation of 100% biomass in conventional power station boilers is the increase in the fouling and corrosion of superheaters. Rapid corrosion of superheaters leads to increased maintenance costs while fouling caused by widespread deposit formation gives rise to a decrease in efficiency of the turbine and an increase in unplanned outages. The purpose of this paper is to report on the effects of fuel additives to change the biofuel chemistry, thus making the fuel less problematic and reducing corrosion and fouling problems. Full-scale trials have been carried out in 35MWth and 105 MWth combined heat and power stations.

    Most biomass fuels have a high content of alkali metals and sometimes high chlorine levels, but they contain very little sulphur compared to fossil fuels. It is thought that the addition of sulphur to the fuel could help to reduce corrosion since a deposit containing only alkali sulphates has a higher first melting point than deposits containing alkali chlorides. Molten phases increase the corrosion and fouling rates and in this sense, sulphates are preferred to chlorides in the deposits.

    To investigate the effect fuel additives, trials were initially performed in a 35 MWth wood-fired circulating fluidised bed boiler, adding controlled amounts of sulphur and a newly developed compound additive, called ChlorOut, to the 100% wood fuel feed or flue gases. It was found that the compound additive, ChlorOut, had a greater effect in removing KCl from the flue gases that pure sulphur, whilst having only a marginal effect on the SOcontent of the flue gas and sulphate content and pH of the flue gas condensate.

    Long term tests with ChlorOut were then repeated in a 105 MWth boiler and in addition corrosion probe testing of superheater steels was performed with and without ChlorOut. The results showed that the ChlorOut additive effectively reduced KCl levels in the flue gas at the superheaters, removed chlorides from the deposits, reduced fouling problems and reduced the corrosion rates by about 50%.

  • 57.
    Henderson, Pamela
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lundberg, Mats
    Sandvik Materials Technology, 811 81 Sandviken, Sweden.
    A steam loop for materials testing at 600C in a biomass and waste fired boiler: results of corrosion testing2010In: 9th Liege conference on Materials for Advanced Power Engineering 2010 / [ed] J. Lecomte-Beckers, Q. Contrepois, T. Beck and B. Kunh, Forschungszentrum Jülich GMbH , 2010, p. 1140-1149Conference paper (Refereed)
    Abstract [en]

    A steam loop for corrosion testing was constructed in Esshete 1250 and attached to one of the superheaters in a 100 MWth bubbling fluidised bed (BFB) boiler. The loop raised the final steam temperature to about600°Cat 140 bar.  A number of different test materials were welded into the loop for evaluation at low temperature (500°Csteam) and high temperature (600°Csteam). Their wall thicknesses were measured with a high resolution ultrasonic probe before and after exposure. A number of sections were examined metallographically after exposure. The steam loop was in service for one firing season (about 5500 h) and the fuel mixture was initially a biomass mix co-firing with 15% coal. However halfway though the firing season the coal was replaced with 15% packaging waste containing plastic and aluminium.  The latter mixture (biomass and waste) was highly corrosive and accounted for most of the corrosion.

     

    The alloys with the highest Ni and Cr contents, Haynes230, AC66 and HR11N, showed negligible steam-side corrosion. The 11% chromium steel X20  and the nickel-base alloy HR11N were not tested at the higher steam temperature because of strength considerations. Regarding fireside corrosion at500°Csteam the alloys with the best corrosion resistance were  Haynes 230, HR11N, AC 66 and HR3C followed by Esshete 1250 and  TP347HFG.  The corrosion rate of X20 was unacceptably high and is totally unsuitable for this fuel mix.  At 600°C  Haynes 230 showed the lowest corrosion rates, followed by TP 347 HFG, HR3C, AC66, and  Esshete 1250. Large amounts of internal corrosion were seen.

  • 58.
    Henderson, Pamela
    et al.
    Vattenfall Research and Development.
    Szakalos, Peter
    Swedish Institute for Metals Research.
    Pettersson, Rachel
    Andersson, Christer
    Högberg, Jan
    Reducing superheater corrosion in wood-fired boilers2006In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 57, no 2, p. 128-134Article in journal (Refereed)
    Abstract [en]

    One of the major drawbacks to the combustion of 100% biomass in power station boilers is the increase in the fouling and corrosion of superheaters. Experience shows that conventional superheater steels last no more than 20 000 h or four operating years before they must be replaced, if 100% wood-based fuel is used and the steam temperature is higher than 480C. Rapid corrosion of superheaters leads to increased maintenance costs while widespread deposit formation gives rise to a decrease in efficiency of the turbine and an increase in unplanned outages.

    This paper reports on measures taken to reduce superheater corrosion. Most biomass fuels have a high content of alkali metals and chlorine, but they contain very little sulphur compared to fossil fuels. Potassium chloride, KCl, is found in the gas phase, condenses on the superheater tubes and forms complex alkali salts with iron and other elements in the steels. These salts have low melting points and are very corrosive. The corrosion can be mitigated by use of an instrument for in-situ measurement of alkali chlorides in the flue gases, in combination with the addition of ammonium sulphate.  An ammonium sulphate solution, specially developed for the reduction of corrosion was sprayed into the flue gases and effectively converted KCl into potassium sulphate, K2SO4, much less corrosive than KCl.

    Deposit probe tests and long-term corrosion probe tests have been performed in-situ in two biomass-fired fluidised bed boilers. One boiler, 105 MW tot, 540C steam, is the CHP plant in Nyköping,Sweden. The other producing 98 MWtot, 480C steam, is a bark-fired boiler at a pulp and paper mill in Munksund, also in Sweden. Tests have been performed with a range of steel types, ferritic and austenitic, with ammonium sulphate additive and under normal conditions (no additive). Corrosion rates have been measured, deposit chemistry analysed and flue gas chemistry and KCl content measured. The structure and composition of the oxide with and without ammonium sulphate has been investigated. The results show that ammonium sulphate reduced the KCl levels in the flue gases, removed the chlorides from the deposits and the metal/oxide interface, greatly reduced the deposition rates and halved the corrosion rates for superheater materials. The alkali chloride measuring system and the use of ammonium sulphate for the reduction of corrosion have now been patented.

  • 59.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Goidanich, Sara
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Corrosion-induced release of Cu and Zn into rainwater from brass, bronze and their pure metals. A 2-year field study2008In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 144, no 1-3, p. 455-461Article in journal (Refereed)
    Abstract [en]

    A 2-year field study has been conducted in an urban environment to provide annual release rates of copper and zinc from brass (20 wt% Zn) and copper and tin from bronze (6 wt% Sn) compared to sheets of their pure alloy constituents, copper and zinc. Despite relatively low nominal bulk alloy content, substantially more zinc was released from brass compared to copper. Both metals were released at a significantly slower rate from the brass alloy, compared to the pure metals. The proportion of release rates of copper and zinc from the alloy differed significantly from their proportions in the bulk alloy. Bronze showed relatively constant release rates of copper, being similar to that of pure copper sheet. The release of tin from bronze was negligible. The results clearly show that alloys and the pure metals behave very differently when exposed to rainwater. Accordingly, release rates from pure metals cannot be used to predict release rates of individual constituents from their alloys. Generated data are of importance within REACH, the new chemical policy of the European commission, where metal alloys erroneously are being treated as mixtures of chemical substances.

  • 60.
    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.

  • 61.
    Hjalmarsson, Niklas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Álvarez Asencio, Rubén
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sweeney, J.
    Shah, F. U.
    Schaufelberger, F.
    Ramström, O.
    Antzutkin, O. N.
    Atkin, R.
    Glavatskih, S.
    Rutland, Mark
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Biodegradable ionic liquids as lubricants2013In: 5th World Tribology Congress, WTC 2013, 2013, Vol. 2, p. 1608-1611Conference paper (Refereed)
  • 62.
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Molecular studies of initial atmospheric corrosion of copper: Exploration of ultra-sensitive techniques for the inhibiting effect of self assembled monolayers, and the effect of gamma radiation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Atmospheric corrosion indoors is of great practical importance for the degradation of metals, for example in electronics, military equipment, and cultural heritage items. It involves a wide range of chemical, electrochemical, and physical processes occurring in gas, liquid, and solid phases, and at the interfaces between them. Hence, a molecular understanding of the fundamental interactions during atmospheric corrosion is of utmost importance.

    Copper is one of the most used metals in electrical contacts, power generators, heat exchangers, etc. and is prone to indoor atmospheric corrosion. Although corrosion and oxidation of copper in the presence of corrosion stimulators is thermodynamically inevitable, there are ways to reduce the kinetics of corrosion and oxidation reactions.

    Self assembled monolayers (SAMs) of organic molecules, when adsorbed on copper surfaces, have proven to be efficient barriers against copper corrosion. However, understanding at the molecular level of the initial stages of corrosion of SAM covered copper in atmospheric corrosion conditions is lacking. The main reason is the inability of the conventional analytical methods to detect and characterize very thin corrosion products formed during the initial stages (from seconds to days) of atmospheric corrosion of SAM covered copper. To overcome this situation a highly surface sensitive technique, vibrational sum frequency spectroscopy (VSFS), has been utilized in situ and ex situ in this thesis to detect and follow the oxidation of alkanethiol SAM covered copper in dry air as well as to assess the conformational changes of SAM molecules during oxidation.  A very sensitive gravimetric method, quartz crystal microbalance with dissipation monitoring (QCM-D), and a highly sensitive and versatile optical technique, nanoplasmonic sensing (NPS), were combined in situ with VSFS to quantify this very slow oxidation process. This combination allowed the heterogeneity of the oxidation process as well as the mass and the rigidity of the corrosion products to be detected simultaneously.

    To address indoor atmospheric corrosion conditions where carboxylic acids play an important role we next studied the interaction between SAM covered copper and humidified air, to which formic acid was added. The in situ identification of the corrosion products and their formation kinetics was done using near surface sensitive infrared reflection/absorption spectroscopy (IRAS), and the effect of hydrocarbon chain length in alkanethiol SAMs on their corrosion protection efficiency was investigated. The effect of the anchoring group in the SAMs on their corrosion protection efficiency was studied for hexaneselenol using -SeH as the anchoring group, and the results were compared with its thiol counterpart, hexanethiol, with -SH as the anchoring group. Complementary in situ and ex situ VSFS measurements were performed to assess the quality of the SAMs before, during, and after exposure.

    It was shown that the SAMs of alkanethiols greatly inhibited the formation of copper (I) oxide and slowed down the formation of other corrosion products, i.e. copper formate and copper hydroxid. This was due to a selective hindrance of the corrosion stimulators, oxygen, water, and formic acid molecules reaching the copper-SAM interface. The corrosion inhibiting effect increased with the hydrocarbon chain length. The SAMs of hexaneselenols, on the other hand, exhibited an accelerated formation of copper (I) oxide, copper formate and copper hydroxide compared to an unprotected surface as a result of the partial removal of hexaneselenol molecules from the copper surface during prolonged exposure.

    The experience gained in characterizing and quantifying thin copper oxides was further used to explore the influence of gamma (γ) radiation on copper corrosion in anoxic water. This multi-analytical approach included IRAS, cathodic reduction, confocal Raman microscope, atomic force microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and inductively coupled plasma - atomic emission spectroscopy. The results clearly showed that copper dissolution as well as the oxide layer thickness increase with gamma radiation under the exposure conditions.

    Download full text (pdf)
    Thesis Saman
  • 63.
    Hosseinpour, Saman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Götelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Self-Assembled Monolayers as Inhibitors for the Atmospheric Corrosion of Copper Induced by Formic Acid: A Comparison between Hexanethiol and Hexaneselenol2014In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 161, no 1, p. C50-C56Article in journal (Refereed)
    Abstract [en]

    The corrosion protection by self-assembled monolayers (SAMs) of hexanethiol and hexaneselenol has been explored on copper exposed to humid air containing formic acid, a corrosive environment relevant for indoor atmospheric corrosion. The kinetics of the formation of corrosion products on SAM covered copper was followed using in-situ infrared reflection/absorption spectroscopy (IRAS) and compared with that of bare copper. Both SAMs initially showed a corrosion protection ability. The prolonged exposure of hexanethiol copper resulted in a reduced formation rate of copper formate and copper hydroxide compared to bare copper, while on bare and hexaneselenol covered samples copper (I) oxide, copper formate, and copper hydroxide were observed. To assess the quality of the SAMs during the sample exposure, vibrational sum frequency spectroscopy (VSFS) was used. It was found that hexaneselenol molecules are locally removed from the surface during corrosion in contrast to their thiol counterparts. This created localized galvanic effects which resulted in an accelerated corrosion of selenol covered copper. X-ray photoelectron spectroscopy at elevated pressure demonstrated that the hexanethiol removed thin oxide layers upon adsorption. A contributing parameter to the enhanced corrosion inhibiting ability of hexanethiol could be its greater ability than hexaneselenol to bind to the copper surface during its deposition and sample exposure.

  • 64. Hou, R. -Q
    et al.
    Ye, C. -Q
    Chen, C. -D
    Dong, S. -G
    Lv, M. -Q
    Zhang, S.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Song, G. -L
    Lin, C. -J
    Localized corrosion of binary Mg-Ca alloy in 0.9 wt% sodium chloride solution2016In: Acta Metallurgica Sinica (English Letters), ISSN 1006-7191, E-ISSN 2194-1289, Vol. 29, no 1, p. 46-57Article in journal (Refereed)
    Abstract [en]

    To further understand the localized corrosion of magnesium alloy, various in situ electrochemical techniques and ex situ electron microprobe analysis and SEM were used to monitor the corrosion process of Mg-1.0Ca alloy in 0.9 wt% sodium chloride solution. The results indicated that the localized corrosion was accompanied by the formation and thickening of a corrosion product film on the Mg-1.0Ca alloy. A localized corrosion of the alloy initiated selectively on the eutectic micro-constituent zones, then enhanced with the exposure, developed in depth with ring-shaped corrosion products accumulated around and finally formed a volcanic-like pitting. Based on the measurements, an electrochemical corrosion model was proposed accordingly to describe the formation mechanism of the volcanic-like pitting on the alloy in 0.9 wt% sodium chloride solution.

  • 65.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Why copper may be able to corrode in pure water2015In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 93, p. 327-329Article in journal (Refereed)
    Abstract [en]

    In exposure of copper to water molecules there will be relatively strong bonds (reversible traps) between copper and hydrogen. One copper-hydrogen bond corresponds to the thermal energy of a temperature of approximately 250 degrees C and this explains an unusual temperature influence on hydrogen uptake in the metal and in corrosion of copper in pure water-vapour without O-2. This unusual temperature influence is exemplified in exposure of copper at 180 degrees C and 500 degrees C where Cu corrodes more at 180 degrees C than at 500 degrees C.

  • 66.
    Hultquist, Gunnar
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Anghel, Clara
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Szakalos, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Effects of hydrogen on the corrosion resistance of metallic materials and semiconductors2006In: High-Temperature Oxidation And Corrosion 2005 / [ed] Taniguchi, S; Maruyama, T; Yoshiba, M; Otsuka, N; Kawahara, Y, 2006, Vol. 522-523, p. 139-146Conference paper (Refereed)
    Abstract [en]

    For long time it is known that protons in aqueous solutions have a detrimental effect on metallic materials. Relatively recently, it has also been observed in aqueous solution that the pitting corrosion resistance of Cr, stainless steel 304 and 310 decreases and the anodic dissolution rate increases due to the presence of hydrogen in the metal. In gas phase a high oxidation rate has been observed for hydrogen containing Cr and Fe. Hydrogen in the substrate can also enhance the oxidation of Fe in SS 316 and As in GaAs. All these results suggest enhanced dissolution in aqueous solution and enhanced oxide growth at the oxide/gas interface in gas phase oxidation due to hydrogen promoted outward-transport of substrate components. A possible mechanism for such out-transport is an increased metal ion diffusivity in the metal-oxide due to a high abundance of metal ion vacancies generated by hydrogen. In contrast to all the above examples, also positive effects of hydrogen have been identified under certain conditions. In an attempt to understand both the negative and the positive effects the concept of a beneficial, balanced oxide growth is used. In this concept a certain amount of hydrogen can be beneficial in the oxidation by improving the balance between oxygen-ion and metalion transport, leading to more dense and protective oxides. Depending on the temperature, H(2) in air is considered as either a sink or a source for hydrogen in materials.

  • 67.
    Hultquist, Gunnar
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Graham, M. J.
    Kodra, O.
    Moisa, S.
    Liu, R.
    Bexell, U.
    Smialek, J. L.
    Corrosion of copper in distilled water without O2 and the detection of produced hydrogen2015In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 95, p. 162-167Article in journal (Refereed)
    Abstract [en]

    This paper reports on hydrogen pressures measured during ~19,000. h immersion of copper in oxygen-free liquid distilled water. Copper corrosion products have been examined ex-situ by SEM and characterized by XPS and SIMS. XPS strongly indicates a corrosion product containing both oxygen and hydrogen. SIMS shows that oxygen is mainly present in the outer 0.3. μm surface region and that hydrogen penetrates to depths well below the corrosion product. Thermal desorption spectroscopy shows that the reaction product formed near room-temperature is less stable than that formed in air at 350. °C.

  • 68.
    Hultquist, Gunnar
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Graham, M. J.
    Smialek, J. L.
    Jonsson, B.
    Hydrogen in metals studied by Thermal Desorption Spectroscopy (TDS)2015In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 93, p. 324-326Article in journal (Refereed)
    Abstract [en]

    This short communication presents Thermal Desorption Spectroscopy (TDS) of hydrogen desorption from various metals and alloys [Au, Pd, Cu, Ni, Zr, Y, stainless steel and ODS (oxide dispersion strengthened) alloy] after long-term exposure (up to 20 years) to ambient humid air at room-temperature. Of the metals studied only gold does not contain a measurable level of hydrogen. For polycrystalline metals there is a strong correlation between the amount of hydrogen in the metal and the tendency for oxidation of the metal.

  • 69.
    Jiang, Tao
    et al.
    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.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Chemical Stability of Chromium Carbide and Chromium Nitride Powders Compared with Chromium Metal in Synthetic Biological Solutions2012In: ISRN Corrosion, ISSN 2090-8903, Vol. 2012, article id 379697Article in journal (Refereed)
    Abstract [en]

    Chromium carbide (Cr-C) and chromium nitride (Cr-N) powders were compared with a chromium metal powder (Cr-metal) to evaluate their chemical stability in solution. All three powders were exposed in five different synthetic biological solutions of varying pH and chemical composition simulating selected human exposure conditions. Characterisation of the powders, using GI-XRD, revealed that the predominant bulk crystalline phases were Cr7C3 and Cr2N for Cr-C and Cr-N respectively. The outermost surface of Cr-C, determined by XPS, contained Cr7C3 and Cr2O3 and the corresponding measurement on Cr-N revealed Cr2N and CrN apart from Cr2O3. The presence of Cr2O3 was verified by XPS investigations of the Cr-metal powder. The mean particle size was similar for Cr-metal and Cr-N but slightly smaller for Cr-C. All three powders were poorly soluble and released very low amounts of chromium (<0.00015 μg Cr/μg loaded particles) independent on test solution. Slightly higher chromium concentrations were determined in the more acidic media (pH 1.7 and 4.5) compared with the near-neutral solutions (pH 7.2 and 7.4). Cr-C released the lowest amount of Cr despite having the largest surface area a feature attributed to the strong covalent bonds within the matrix.

  • 70.
    Jiang, Tao
    et al.
    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.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Metal release studies of Cr from CrC and CrN in synthetic biological media and in the OECD T/D media2011Report (Other academic)
  • 71.
    Karasev, Andrey
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Alekseeva, E.
    Lukianov, A.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Characterization of non-metallic inclusions in corrosion -resistance nickel - Based EP718 and 718 alloys by using electrolytic extraction method2019In: E3S Web of Conferences, EDP Sciences , 2019Conference paper (Refereed)
    Abstract [en]

    It is known that non-metallic inclusions (NMI) that are formed during steel production and heat treatment can significantly affect the properties of final steel products. Therefore, it is very important to be able to determine the content of harmful NMI in steels. Nickel-based alloys are widely used in the oil and gas recovery industry, due to a good combination of strength and corrosion properties. Earlier studies have shown that the corrosion properties in immersion test and electrochemical tests for Ni-based EP718 alloys are slightly lower than that for 718 alloys. The focus in this study was the influence of different NMI on the corrosion resistance of these alloys. The characteristics of inclusions (such as size, morphology, and chemical composition) were analysed by using the electrolytic extraction method followed by three-dimensional investigations using SEM in combination with EDS. It was found that some non-metallic inclusions in EP718 alloys significantly reduce its corrosion resistance. It was also shown that a primary dissolution of the metal matrix occurs around certain inclusions during electrolytic extraction. Based on obtained results, the corrosion active non-metallic inclusions can be determined in these Nickel-base alloys and some recommendations for optimization of their production technology can be formulated.

  • 72.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design. KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Durability Evaluation of Reinforced Glass-Flake Polyester Material Used in Rehabilitation of Sewer Lines in Buildings-Dataset2019Data set
    Abstract [en]

    This dataset includes original data to support parts of research findings stated in the article: ”Durability evaluation of reinforced glass-flake polyester material used in rehabilitation of sewer lines in buildings”. Currently, different materials and methods are in use in alternative rehabilitations technologies for sewer renewal. This work was conducted to study one of these materials, which is a glass -flake reinforced polyester polymeric system, during artificial aging to provide a better understanding of the material’s performance under operating conditions when it is regularly exposed to degrading factors such as high temperature and water. Changes in the material during aging were monitored by conducting different tests, including thermal and mechanical analysis, water absorption and microscopy.

    The full text will be freely available from 2021-01-01 13:09
    The full text will be freely available from 2021-01-01 12:53
  • 73.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Durability study of reinforced polyester composite used as pipe lining under artificial aging conditionsIn: Article in journal (Refereed)
    Abstract [en]

    The aging of sewer infrastructure is an ongoing problem. As a result, different materials and methods are being used in alternative sewer rehabilitation approaches. This work was conducted to study one pipe lining, namely the reinforced polyester composite, under artificial aging; this was done to provide a better understanding of the material’s performance under operating conditions, where it is regularly exposed to degrading factors such as heat and water. Aging of the material was monitored by means of several tests, including thermal and mechanical analyses, water absorption and microscopy. The results showed that the combination of aging in water and at high temperatures resulted in greater effects on the material compared to aging at high temperatures in dry conditions. Although the measured properties were affected significantly when immersed in water at high temperatures, the material showed acceptable properties at lower exposure temperatures close to the expected temperature inside sewer systems.

  • 74.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Evaluation of Innovative Rehabilitation Technologies Utilising Polymer Composites for Aging Sewer Systems2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Water and wastewater sewer system maintenance is among the costliest aspects of infrastructure investment. The replacement of deteriorated lines is a difficult and expensive process that causes community disturbance and is generally not conducted fast enough to meet demand. To keep up with the rate of deterioration, the use of alternative rehabilitation technologies using polymer linings has increased significantly in recent years, both within Sweden and worldwide. Compared to the traditional pipe replacement method, these technologies are cost-effective, create less community disturbance, and offer a quick return to the service for the line. The main function of polymeric lining is to stabilise the condition of the pipeline, eliminate deterioration, and thereby extend the pipeline’s service life. Although rehabilitation technologies employing polymeric systems have been in use for over 30 years, there have been few technical assessments of either these technologies or the materials involved. Data gathered through the evaluation of these innovative technologies can make their benefits and limitations more widely understood, and can also be used to increase the effectiveness of the rehabilitation process in future.

    The main objective of this work was to contribute to an improved understanding of the most commonly used materials and methods employed in rehabilitation of wastewater and other applicable sewer lines in residential buildings in Sweden. The primary objective was not to prove that the emerging rehabilitation technologies work, but rather to increase knowledge of their weaknesses and strengths, identify any issues, and provide a technical assessment to support realistic expectations of pipeline rehabilitation. Gathering technical information in this way will help with the planning of future investigations; moreover, collecting extensive data will help to increase the effectiveness of the renewal works, aid progress in the field, and improve predictions regarding longevity and service life.

    As pipeline rehabilitation is still considered novel, and owing to the general lack of available data on the subject, a multi-approach study was carried out: this included evaluation of the polymeric materials’ performance in the presence of deteriorative factors, assessing the in-service state of the materials and lined sewers previously installed, monitoring the level of quality control implemented during previous rehabilitation works, and evaluating the environmental impacts of using pipe-lining technologies compared to pipe replacement. The techniques discussed included rehabilitation with epoxy and polyester resin-based lining materials, applied with brush-on and spray-on techniques, and cured-in-place pipe lining (installed by sending a resin-impregnated flexible tube inside the host pipe).

    Degradation of the resin-based lining materials was investigated via artificial aging involving immersion in water at elevated temperatures. The changes in materials that occurred during accelerated laboratory aging were tracked by means of various tests, including thermal and mechanical analyses, water absorption measurements and microscopy. The analysis focused on reinforced polyester-based and toughened epoxy-based lining materials in order to gain a better understanding of their performance as pipe lining. Moreover, the previously installed lined pipes and lining materials were also studied during laboratory examinations to evaluate the in-service performance of the materials and techniques under operating conditions over time, as well as to identify common defects. The state of the materials and the lined pipe were studied by means of different investigative methods, including visual inspection, microscopy, Fourier transform infrared spectroscopy, thickness measurement, thermal and mechanical analyses. This PhD work also includes an investigation to determine the level of quality control carried during some previous rehabilitation works. Data on the quality evaluation of previous rehabilitation works were gathered during visits to the work sites, as well as by analysing lined pipes that had already been installed. Finally, a comparative life-cycle assessment was undertaken to compare the environmental impacts of pipe replacement with those of alternative innovative rehabilitations, such as CIPP and coatings with polyester and epoxy polymeric systems. Data obtained from an LCA tool were used to facilitate comparison from an environmental perspective.

    Results from artificial aging in the lab indicated that the properties of polymeric lining materials changed significantly when high temperatures were combined with water exposure. However, the aging testing conducted for this study also found that the materials performed relatively well at temperatures close to the average temperatures inside sewerage systems. The results revealed that the polyester-based lining material was less sensitive when compared with epoxy-based lining materials during stimulated aging. Moreover, results from the in-service field demonstration (involving examination of 12 samples with up to 10 years of service, including reinforced polyester and modified epoxy linings or cured-in-place pipe (CIPP) lining) showed minimal evidence that the materials underwent significant deterioration after installation; instead, a majority of the common defects were found to be related to poor-quality installation practices. Because very few field samples were available to study, conclusions regarding overall performance could not be drawn. However, there is no evidence that these materials will not perform as expected during their service life when properly installed.

    Evaluating quality control of previous rehabilitation work revealed a gap between theory and practice where the level of quality control and documentation was concerned; furthermore, it also emerged that quality control and documentation is crucial to both the prevention of common issues and the overall effectiveness of the rehabilitation. Accordingly, a series of recommendations regarding the development of comprehensive quality control and quality assurance procedures (QC/QA) are provided in this work. These recommendations highlight the aspects that are most important to consider at each of several key stages (before installation, during installation, and after rehabilitation work is completed).

    Results from comparative life-cycle assessment (LCA) showed that alternative technologies, including cured-in-place (flexible sleeve) and coating techniques, have some advantages over pipe replacement from an environmental perspective. However, the choice to use one rehabilitation technology over another is a multi-stage decision-making process that should not be based solely on a single factor.

    This PhD work promotes an improved understanding of the limitations and benefits of polymeric lining through the testing performed and analyses conducted. This work highlights the need for improved quality control, and further suggests that developing a detailed and comprehensive quality control plan for each technology would provide higher and more consistent quality overall. The study also demonstrates that the long-term strength of any rehabilitation work depends on various factors, and that selecting one method over another must be a process based on extensive knowledge and understanding of each rehabilitation technology. No evidence was found to indicate that the materials could not perform well under working conditions if selected and installed appropriately. However, a larger number of field samples with longer in-service time and a more detailed technical history, along with a more extended experimental plan for laboratory investigations based on the results of this PhD work, will allow for the gathering of the data required to answer questions regarding life expectancy with a higher degree of certainty.

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  • 75.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Experimental assessment of the state of the lining materials used in the rehabilitation of sewers in residential buildingsIn: Article in journal (Refereed)
  • 76.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE).
    Monitoring quality of sewer renewal using polymeric systems in Sweden- data set2019Data set
    Abstract [en]

    This data set includes data to support research findings stated in the article: 

    Monitoring quality of waste-water sewer pipe rehabilitations using polymeric systems

    Download full text (xlsx)
    Monitoring thickness of liners
  • 77.
    Kharazmi, Parastou
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Monitoring the gelation time and curing process of a reinforced polyester lining-original data2019Data set
    Abstract [en]

    Polymer linings used in sewer rehabilitation technologies are expected to cure fast in order for the renewed line to return to the service quickly and with minimum disruption.  This dataset includes the original data obtained from the thermal analyses of a reinforced polyester composite used as pipe lining, including studying gelation, enthalpy and curing process for a better understanding of the material's curing behaviour after application in the field. 

    The full text will be freely available from 2021-01-01 12:58
  • 78.
    Kharitonov, D. S.
    et al.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk 220006, Byelarus.;KTH Royal Inst Technol, Surface & Corros Sci Div, Drottning Kristinas Vag 51, SE-10044 Stockholm, Sweden..
    Dobryden, Illia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sefer, B.
    Lulea Univ Technol, Div Mat Sci, SE-97187 Lulea, Sweden..
    Zharskii, I. M.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk 220006, Byelarus..
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kurilo, I. I.
    Belarusian State Technol Univ, Dept Phys Colloid & Analyt Chem, Minsk 220006, Byelarus..
    Corrosion of AD31 (AA6063) Alloy in Chloride-Containing Solutions2018In: PROTECTION OF METALS AND PHYSICAL CHEMISTRY OF SURFACES, ISSN 2070-2051, Vol. 54, no 2, p. 291-300Article in journal (Refereed)
    Abstract [en]

    Corrosion of AD31 (AA6063) alloy in neutral 0.05 M NaCl solutions is investigated via scanningprobe microscopy, linear-sweep voltammetry, and electrochemical-impedance spectroscopy. Al-Fe-Si-Mg intermetallic particles are determined to prevail in the structure of alloy and act as local cathodes. Intermodulation electrostatic-force-microscopy imaging shows that their Volta potential differs by 570 mV from that of the host aluminum matrix, making the alloy prone to localized corrosion. We show that the corrosion of alloy in the studied electrolyte mainly develops locally and results in pitting, with charge transfer being the limiting stage of the process. A mechanism of corrosion of the AD31 (AA6063) alloy in neutral chloride-containing solutions is proposed.

  • 79.
    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.

  • 80.
    Korzhavyi, Pavel A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Soroka, Inna L.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Isaev, Eyvaz I.
    Lilja, Christina
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Exploring monovalent copper compounds with oxygen and hydrogen2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 3, p. 686-689Article in journal (Refereed)
    Abstract [en]

    New important applications of copper metal, e.g., in the areas of hydrogen production, fuel cell operation, and spent nuclear fuel disposal, require accurate knowledge of the physical and chemical properties of stable and metastable copper compounds. Among the copper(I) compounds with oxygen and hydrogen, cuprous oxide Cu(2)O is the only one stable and the best studied. Other such compounds are less known (CuH) or totally unknown (CuOH) due to their instability relative to the oxide. Here we combine quantum-mechanical calculations with experimental studies to search for possible compounds of monovalent copper. Cuprous hydride (CuH) and cuprous hydroxide (CuOH) are proved to exist in solid form. We establish the chemical and physical properties of these compounds, thereby filling the existing gaps in our understanding of hydrogen- and oxygen-related phenomena in Cu metal.

  • 81.
    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.

  • 82.
    Levin, Martina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Application of copper corrosion inhibitors in mineral oil: Surface analytical studies and corrosion mitigation evaluations2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This doctoral thesis explores the copper corrosion inhibiting properties of a number of nitrogen containing hetero-organic compounds in refined mineral oil. Traditional organic corrosion inhibitors, as well as novel and bioorganic compounds have been studied.

    The Hansen solubility parameters were determined for the three commercial organic corrosion inhibitors; benzotriazole, tolyltriazole and Irgamet 39™, an N-(aminomethyl) substituted triazole. The determination was done using an indirect method utilizing the solubility of the inhibitors in various solvents. The calculated Hansen solubility parameters of the inhibitors were compared with the Hansen solubility parameters and solubility sphere of refined mineral oil. The obtained Hansen solubility parameters of benzotriazole indicate very low solubility in mineral oils, while the solubility of tolyltriazole was slightly higher due to the methyl substitution. The obtained Hansen solubility parameters of Irgamet 39™ indicate full miscibility with refined mineral oil. The adsorption kinetics of the inhibitors on copper surfaces in refined mineral oil was studied by means of in situ ellipsometry and related to the Hansen solubility parameters. A good correlation was seen; the compound with the highest solubility (Irgamet 39™) generated the thinnest film, while the greatest film thickness was seen for the molecule with the lowest solubility (benzotriazole).

    The issue of decomposition of the N-(aminomethyl) substituted Irgamet 39™ and Irgamet 30™ upon adsorption was addressed and analysed by using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The ToF-SIMS study revealed that both compounds appeared to lose their aminomethyl tails upon adsorption. No signals from the intact molecules were detected.

    The possibility of utilising bio-organic substances as organic corrosion inhibitors has been examined. The copper corrosion inhibiting effects of four bioorganic compounds; adenine, purine, cysteine and histidine were studied by in situ ellipsometry, copper dissolution, and a standardised industrial corrosion test developed by the International Electrotechnical Commission (IEC 62535). Adenine and purine were found to adequately mitigate copper corrosion, while cysteine and histidine were found to have low, or even accelerating, effects on the corrosion rate.

    The corrosion inhibiting properties of five benzo-fused azoles; benzotriazole, benzimidazol, indole, benzothiazole and benzothiadiazole in refined mineral oil were analysed by means of ellipsometry, ToF-SIMS, copper dissolution studies and the standardised industrial corrosion test (IEC 62535). It was demonstrated that copper corrosion was mitigated by the addition of benzotriazole and benzimidazole. However, addition of indole, benzothiazole and benzothiadiazole did not generate any significant corrosion mitigating effect. In general, the corrosion inhibition efficiency of the investigated molecules was found to decrease with increased polarizability of the molecule.

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  • 83.
    Li, Jing
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE KIMAB AB, RISE Res Inst Sweden, Div Mat & Prod, S-16440 Kista, Sweden..
    Ecco, Luiz
    Univ Trento, Dept Ind Engn, I-38123 Trento, Italy..
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, SE-11486 Stockholm, Sweden..
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Probing electrochemical mechanism of polyaniline and CeO2 nanoparticles in alkyd coating with in-situ electrochemical-AFM and IRAS2019In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 132, p. 399-408Article in journal (Refereed)
    Abstract [en]

    The corrosion protection and electrochemical mechanism of solvent-borne alkyd composite coating containing 1.0 wt.% polyaniline (PANI) and 1.0 wt.% CeO2 nanoparticles (NPs) for carbon steel in 3.0 wt.% NaCl solution were investigated by means of scanning electron microscopy (SEM), ex-situ, in-situ and electrochemical controlled (EC) atomic force microscopy (AFM), open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) methods. The SEM and ex-situ AFM results revealed the micro- and nanostructure of the composite coating. The in-situ sequential AFM images and line profiling analysis indicated electrochemical activity of the NPs and a high stability of the composite coating in NaCl solution. The results of EC-AFM combined with cyclic voltammetry (CV) demonstrated volume change of the PANI NPs upon reduction and oxidation at certain applied potentials on the coating. The redox reactions between the different forms of PANI and the effect of the CeO2 NPs on the polymerization of the composite polymer were further confirmed by infrared reflection absorption spectroscopy (IRAS). The OCP and EIS results revealed that the composite coating provided an improved corrosion protection for carbon steel within several days of exposure, which was attributed to the barrier protection of CeO2 NPs and the passivation ability of PANI.

  • 84.
    Li, Jing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ecco, Luiz
    Delmas, Gregory
    Whitehouse, Nigel
    Collins, Peter
    Deflorian, Flavio
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    In-Situ AFM and EIS Study of Waterborne Acrylic Latex Coatings for Corrosion Protection of Carbon Steel2015In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, no 1, p. C55-C63Article in journal (Refereed)
    Abstract [en]

    Corrosion protection for carbon steel by three waterborne styrene-acrylic latex coatings with different glass transition temperature (Tg) and levels of hydrophobicity has been studied by in-situ atomic force microscope (AFM) and electrochemical impedance spectroscopy (EIS) measurements in 3.0 wt% NaCl solution. The AFM images reveal the micro-and nano-structure of and pinholes in the coatings as well as their changes during exposure in the solution, whereas the EIS spectra vs. time of exposure show the barrier property, stability and degradation of the coatings. The coating with crosslinking and high level of hydrophobicity exhibited a high barrier property and long-term corrosion protection in the solution despite of some shallow pinholes. The coating without crosslinking but having high Tg and high level of hydrophobicity also displayed a high barrier property and certain stability although initial changes occur in the solution. However, for the coating without crosslinking and with low Tg and relative low level of hydrophobicity, some dissolution and open-up of defects occurred on the surface shortly after exposure and the coating lost its barrier property rapidly in the solution. The reasons for the different behaviors between the coatings are discussed with respect to the crosslinking, Tg and the hydrophobicity level of the coating.

  • 85.
    Li, Jing
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ecco, Luiz
    Schellbach, C.
    Claesson, Per M.
    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 AFM and Electrochemical AFM Investigation of Corrosion Protection of Solventborne Alkyd: Polyaniline Composite Coating for Carbon SteelManuscript (preprint) (Other academic)
  • 86.
    Liljeblad, Jonathan F.D.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Bulone, Vincent
    KTH, School of Biotechnology (BIO), Glycoscience.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Stability and structure of phospholipid monolayers probed by vibrational sum frequency spectroscopy (VSFS)2010In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 239Article in journal (Other academic)
  • 87.
    Lindström, David J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Long-term barrier effects of Cr (III)- and Cr (VI)- treated zinc surfaces on metal release2008In: Int. Corros. Congr.: Corros. Control Serv. Soc., 2008, p. 2573-2583Conference paper (Refereed)
    Abstract [en]

    The recently implemented legislation regarding handling of chemicals in the European Union, and a generally increased environmental awareness in the society have generated a need to quantify diffuse metal flows from metallic product surfaces. The use of Cr(VI) in surface treatments on external constructions (e.g. on galvanized steel) is questioned and powerfully restrained by this legislation. Therefore, environmentally friendly alternatives based on e.g. Cr(III) are now available on the market. In this study, corrosion-induced changes in barrier effects in terms of release of zinc and chromium and changes in surface properties with time were investigated for bare zinc sheet and continuously galvanized steel with surface treatments based on Cr(III) or Cr(VI) in long-term field exposures at an urban (Stockholm, Sweden) and a marine site (Brest, France). Essential key information is generated to assess potential adverse environmental effects caused by the use of these surface treatments. Preliminary results from the urban site show the Cr(VI)-based surface treatments, at least initially, to have a higher barrier effect for zinc release compared to the Cr(III)-based surface treatment. Both surfaces resulted in significantly lower release rates of zinc compared to bare zinc sheet. Chromium was released from both surface treatments (Cr(VI)≫Cr(III)) at significantly lower rates compared to zinc, whereby the rates decreased with time.

  • 88.
    Lundin, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jiang, T.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wang, X.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Blomberg, Eva
    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.
    Adsorption and protein-induced metal release from chromium metal and stainless steel2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 366, no 1, p. 155-164Article in journal (Refereed)
    Abstract [en]

    A research effort is undertaken to understand the mechanism of metal release from, e.g., inhaled metal particles or metal implants in the presence of proteins. The effect of protein adsorption on the metal release process from oxidized chromium metal surfaces and stainless steel surfaces was therefore examined by quartz crystal microbalance with energy dissipation monitoring (QCM-D) and graphite furnace atomic absorption spectroscopy (GFAAS). Differently charged and sized proteins, relevant for the inhalation and dermal exposure route were chosen including human and bovine serum albumin (HSA, BSA), mucin (BSM), and lysozyme (LYS). The results show that all proteins have high affinities for chromium and stainless steel (AISI 316) when deposited from solutions at pH 4 and at pH 7.4 where the protein adsorbed amount was very similar. Adsorption of albumin and mucin was substantially higher at pH 4 compared to pH 7.4 with approximately monolayer coverage at pH 7.4, whereas lysozyme adsorbed in multilayers at both investigated pH. The protein-surface interaction was strong since proteins were irreversibly adsorbed with respect to rinsing. Due to the passive nature of chromium and stainless steel (AISI 316) surfaces, very low metal release concentrations from the QCM metal surfaces in the presence of proteins were obtained on the time scale of the adsorption experiment. Therefore, metal release studies from massive metal sheets in contact with protein solutions were carried out in parallel. The presence of proteins increased the extent of metals released for chromium metal and stainless steel grades of different microstructure and alloy content, all with passive chromium(III)-rich surface oxides, such as QCM (AISI 316), ferritic (AISI 430), austentic (AISI 304, 316L), and duplex (LDX 2205).

  • 89.
    Odnevall Wallinder, Inger
    et al.
    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.
    A Critical Review on Corrosion and Runoff from Zinc and Zinc-Based Alloys in Atmospheric Environments2017In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 73, no 9, p. 1060-1077Article, review/survey (Refereed)
    Abstract [en]

    This critical review aims at addressing important issues concerning zinc corrosion and zinc runoff processes of zinc or zinc alloyed with aluminum or magnesium exposed to atmospheric environments. The evolution of the corrosion product (patina) layer is very important for both processes. While corrosion largely is controlled by electrochemical reactions at the metal/patina interface, runoff is predominantly governed by chemical reactions at the patina/atmosphere interface. The gradual evolution of compounds in zinc patina follows one of two main routes: one in more sulfur-dominated and one in more chloride-dominated environments. Because of climatic changes and reduction of sulfur-containing atmospheric species in many parts of the world, the chloride-route is expected to dominate over the sulfur-route. Alloying with aluminum and magnesium results in substantial improvement in corrosion protection, whereby several mechanisms have been proposed. The released amount of zinc is highly dependent on the amount of rainfall, also on sulfur dioxide concentration or deposition, and to only a low extent on chloride deposition. Based on all runoff data, a model is presented which predicts 70% of all observed zinc runoff rates within 40% from their measured value.

  • 90.
    Persson, Lukas
    KTH, School of Chemical Science and Engineering (CHE).
    Biodiesel production by heterogeneous catalysis - experimental study and kinetic modelling2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This work comprises two related studies regarding heterogeneous catalysts for production of biodiesel through transesterification of vegetable oils. For the experimental work a porous, anionic type ion-exchange catalyst (Diaion PA306s) was employed in a batch process with Jatropha curcas oil and methanol as reactants. For the theoretical work on a kinetic model, the considered system was a heterogeneous alkali catalyst, Li doped CaO on ZnO as support material, used with rapeseed oil and methanol.

    In the experimental study, the effects of various reaction conditions were to have been tested for the purpose of designing a kinetic model and evaluating its kinetic parameters. The experimental work was however ended prematurely and the experimental data collected thus far were insufficient to reach the objective. In spite of this a few conclusions were reached: the reaction seems to give high yields even for non-optimal reaction conditions, but the reaction rate may be too low for a batch process. Due to promising results from previous work on this catalyst, more experiments ought to be executed and a kinetic model derived.

    The theoretical work on the kinetic model serves as an illustration of how the model would have been constructed based on experimental data in the experimental study. The reaction mechanism was assumed to be Eley-Rideal-type mechanism, in which methanol adsorbed to the catalyst surface reacts with triglyceride in the reaction solution. The model fitted experimental data fairly well and the reaction rate constant for the surface reaction was determined.

  • 91. Pettersson, Rachel
    et al.
    Flyg, J.
    Viklund, Peter
    Materials performance in simulated waste combustion environments2008In: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 43, no 2, p. 123-128Article in journal (Refereed)
    Abstract [en]

    Combustion of waste for power generation gives increased fouling and corrosion compared to fossil fuels, and leads to higher operating and maintenance costs. New materials solutions to increase lifetime include austenitic stainless steels, nickel base alloys, coatings and weld overlaying. In this work a simulated waste incineration environment with regularly renewed deposits of KCl - ZnCl(2) has been used to evaluate the performance of candidate materials and to elucidate the operative degradation mechanisms.

  • 92.
    Qadeer, Muhammad I.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Azhdar, Bruska
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Savage, S. J.
    Anomalous high temperature oxidation of Sm 2(Fe,Co,Cu,Zr) 17 particles2012In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 65, p. 453-460Article in journal (Refereed)
    Abstract [en]

    Sm 2Co 17 alloys are attractive as high temperature permanent magnets; however their magnetic properties are prone to degrade by oxidation. The oxidation mechanism is not clearly understood, and inconsistent results are reported in the literature.This work correlates the oxidation of Sm 2(Co,Fe,Cu,Zr) 17 with microstructural and microchemical changes as a consequence of chemical reaction of alloy particles with their environment at high temperature. Thermogravimetric analysis suggests a change in oxidation mechanism occurs at 550°C. Energy dispersive X-ray spectroscopy suggests this is related to the loss of Sm by sublimation.

  • 93.
    Qiu, Ping
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Hedberg, Jonas F.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Persson, D.
    Initial atmospheric corrosion of zinc induced by acetic acid: A quantified in situ IRAS study2008In: Int. Corros. Congr.: Corros. Control Serv. Soc., 2008, p. 1569-1574Conference paper (Refereed)
    Abstract [en]

    As part of a broader research program dealing with initial atmospheric corrosion of metals induced by organic acids, infrared reflection absorption spectroscopy (IRAS) has been used to study the initial interaction of acetic acid with zinc in 90% relative humidity and 120 ppb acid concentration under in situ condition. Efforts were made to quantify the identified reaction product species, mainly zinc oxide and zinc acetate. The experimentally obtained results were quantified through calculations using a linear relationship between IRAS peak intensity and layer thickness, and assuming optical constants of zinc acetate dihydrate (Zn(CH 3COO) 2•2H 2O). In all, the in situ studies performed by IRAS provide information on the identity and quantity of reaction products formed.

  • 94.
    Reza Gholi, Ashkan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Effects of tempering on corrosion properties of high nitrogen alloyed tooling steels in pyrolysis oil2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowdays biofuels are becoming a good alternative for petroleum fuels due to environmental issues like high carbon dioxide emission and increasing vehicles population, together with the high price and fast depletion of petroleum oils. This project aims to investigate the corrosive effects of wood Pyrolysis oil on a special grade of nitrogen alloyed tooling steels to be used for injector nozzles in Diesel engines, where high stress and strain encounter high acidity and corrosivity of the Pyrolysis oil and cause breakdown over short periods. Vanax 35 and Vanax 75 manufactured in Uddeholm are two types of powder metallurgy high nitrogen alloyed martensitic stainless steel with a high combination of hardness (over 56HRC), low friction properties, wear resistance, anti-galling and corrosion properties. In this work, the newly developed Vanax material together with the tool steels Elmax and AISI O1 were tempered at various temperatures from 200°Cto 500°C. The tempered steels were then exposed in pyrolysis oil at 4 different temperatures, 20°C, 70°C, 95°Cand 130°C. The materials were investigated by means of corrosion rate measurements, microscopy (LOM, SEM, confocal) and Thermo-Calc calculations. The corrosion rate measurement proved that Vanax tempered at lower ranges (200°C, 400°Cand 450°C) showed the best corrosion resistance while higher tempering temperatures such as 500°C, Elmax and AISI O1 tempered at 200°Csuffered a great deal of general corrosion attack. Thermo-Calc calculations showed the formation of a hard phase, VN as primary nitrides instead of primary chromium carbides at austenizing temperature for the Vanax group. Higher amount of chromium is dissolved in solid solution in Vanax at austenizing temperature hence the martensite matrix has, after quenching, a higher chromium content that helps passivation. The loss in corrosion properties at higher tempering temperatures was due to the formation of CrN secondary phase at around 400˚C which reduces the chromium content of the martensite matrix. The results of light optical and confocal microscopy showed the presence of pits when tempering at 400˚C and 450˚C. No pits were observed at 200˚C. Elmax was not passivated at all which resulted in general corrosion attacks, due to a high chromium loss from the austenite solid solution at the austenizing procedure temperature and also the tempering temperatures. The chromium depletion from the austenite can be explained by a high carbon and a low nitrogen content in the composition which resulted in formation of a high amount of Cr7C3.

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  • 95.
    Rosborg, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Eden, D.
    Karnland, O.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Werme, L.
    Real-time monitoring of copper corrosion at the Äspö HRL2004Conference paper (Refereed)
    Abstract [en]

    In Sweden the principal strategy for high-level radioactive waste disposal is to enclose the spent nuclear fuel in tightly sealed copper canisters that are embedded in bentonite clay about 500 m down in the Swedish bed-rock. Initially, a limited amount of air will be left in a repository after emplacement. The entrapped oxygen will be consumed through reactions with minerals in the rock and the bentonite and also through microbial activity. After the oxygen has been consumed in the repository, after a few hundred years at the very most, corrosion will be controlled completely by the supply of dissolved sulphide to the canister. The present work concerns the oxic period after emplacement. The main hypothesis is that the average corrosion rate of the canister under oxic conditions will be less than 7 μm/year, and that pitting will only be possible under these conditions. The Äspö Hard Rock Laboratory offers a realistic environment for different experiments and tests under the conditions that will prevail in a deep repository. Real-time monitoring of copper corrosion is presently performed with polarization resistance, harmonic distortion analysis and electrochemical noise techniques. The first two techniques are used to derive information regarding the general corrosion rate and the third to derive information regarding localized corrosion. In order to support these measurements at Äspö, laboratory work is also performed at the Royal Institute of Technology in Stockholm using the very same corrosion monitoring equipment and also other equipment and techniques. Copper coupons are also exposed at Äspö. Results from the work at Äspö and in Stockholm are presented with an emphasis on the gained information concerning localized corrosion. The recorded corrosion rates at Äspö are well below the value given above, and the recorded localization factors are interpreted as indicating only a slight tendency to local attack.

  • 96.
    Sababi, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Nanocomposite films for corrosion protection2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes technical and scientific aspects of new types of composite films/coatings for corrosion protection of carbon steel, composite films with nanometer thickness consisting of mussel adhesive protein (Mefp1) and ceria nanoparticles, and polymeric composite coatings with micrometre thickness consisting of conducting polymer and ceria nanoparticles in a UV‐curing polyester acrylate (PEA) resin.

    The influence of microstructure on corrosion behaviour was studied for a Fe‐Cr‐V‐N alloy containing micro‐sized nitrides with different chemical composition spread in martensitic alloy matrix. The Volta potential mapping suggested higher relative nobility for the nitride particles than the alloy matrix, and the nitrides with higher amounts of nitrogen and vanadium exhibited higher nobility. Potentiodynamic polarization measurements in a 0.1 M NaCl solution at neutral pH and ambient temperature showed passivity breakdown with initiation of localized corrosion which started in the boundary region surrounding the nitride particles, especially the ones enriched in Cr and Mo.

    Mefp1/ceria nanocomposite films were formed on silica and metal substrates by layer‐by‐layer immersion deposition. The film formation process was studied in situ using a Quartz Crystal Microbalance with Dissipation (QCM‐D). The film grows linearly with increasing number of immersions. Increasing Mefp1 concentration or using Mefp1 with larger size leads to more Mefp1 being deposited. Peak Force Quantitative Nanomechanical Mapping (Peak Force QNM) of the composite films in air indicated that the elastic modulus of the film increased when the film deposited had a higher Mefp1 concentration. It was also noted that the nature of the outermost layer can affect bulk morphology and surface mechanical properties of the film.

    The QCM‐D study of Mefp1 on an iron substrate showed that Mefp1 adsorbs at a high rate and changes its conformation with increasing adsorption time. The QCM‐D and in situ Peak Force QNM measurements showed that the addition of Fe3+ ions causes a transition in the single Mefp1 layer from an extended and soft layer to a denser and stiffer layer. In situ ATR‐FTIR and Confocal Raman Microscopy (CRM) analyses revealed complex formation between Fe3+ and catechol groups in Mefp1. Moreover, optical microscopy, SEM and AFM characterization of the Mefp1/ceria composite film formed on carbon steel showed micron‐size aggregates rich in Mefp1 and ceria, and a nanostructure of well dispersed ceria particles in the film. The CRM analysis confirmed the presence of Mefp1/Fe complexes in the film. Electrochemical impedance microscopy and potentiodynamic polarization measurements showed that the Mefp1/ceria composite film can provide corrosion protection for carbon steel, and that the protection efficiency increases with exposure time.

    Composite coatings of 10 μm thickness composed of a UV‐curing PEA resin and a small amount of conductive polymer and ceria nanoparticles were coated on carbon steel. The conductive polymer (PAni) was synthesized with phosphoric acid (PA) as the dopant by chemical oxidative polymerization. The ATR‐FTIR and SEM analyses confirmed that the added particles were well dispersed in the coatings. Electrochemical measurements during long exposure in 0.1 M NaCl solution, including open circuit potential (OCP) and EIS, were performed to investigate the protective performance of the coatings. The results showed that adding ceria nanoparticles can improve the barrier properties of the coating, and adding PAni‐PA can lead to active protection of the coating. Adding PAni‐PA and ceria nanoparticles simultaneously in the coating can improve the protection and stability of the composite coating, providing excellent corrosion protection for carbon steel.

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    Thesis
  • 97.
    Sababi, Majid
    et al.
    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.
    Augustsson, Per-Erik
    Sundell, Per-Erik
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The Influences of Conducting Polymer and Ceria Nanoparticles Additives on Corrosion Resistance Behavior of UV‐cure CoatingsManuscript (preprint) (Other academic)
  • 98.
    Sababi, Majid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Zhang, Fan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Krivosheeva, Olga
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Forslund, Mattias
    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.
    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.
    Thin Composite Films of Mussel Adhesive Proteins and Ceria Nanoparticles on Carbon Steel for Corrosion Protection2012In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, no 8, p. C364-C371Article in journal (Refereed)
    Abstract [en]

    Thin composite films of the mussel adhesive proteins (Mefp-1) and ceria nanoparticles were deposited on substrate surfaces by alternating immersions. The film formation was studied by quartz crystal microbalance with dissipation (QCM-D) monitoring. Both the changes in frequency and dissipation recorded by QCM-D demonstrate buildup of a composite film of Mefp-1 and nanoceria. Micro-and nanostructure and composition of the film on carbon steel were characterized by optical and atomic force microscopy (AFM), electron probe micro analyzer (EPMA) and confocal Raman microspectroscopy (CRM). Optical and EPMA observations of the film show micron-sized aggregates and AFM imaging of the compact and smooth areas reveal the nanostructure. EPMA elemental mapping indicates that the micron-sized aggregates are rich in ceria and Mefp-1, whereas CRM analysis shows the presence of Mefp-1-Fe complexes in the film. Corrosion protection of the composite film on carbon steel was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements in NaCl solution, and compared with Mefp-1 added in the solution as an inhibitor. The measurements show that the composite film provides a higher corrosion resistance compared with Mefp-1 added as inhibitor. The corrosion resistance increases with exposure time and approaches a high level.

  • 99.
    Shinohara, T.
    et al.
    National Institute for Materials Science, Japan.
    Brunk, Jon
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. National Institute for Materials Science, Japan.
    Critical potential for propagation of stress corrosion cracking2008In: Critical Factors in Localized Corrosion 6, in Honor of Professor Shibata, 2008, no 52, p. 255-268Conference paper (Refereed)
    Abstract [en]

    Critical potentials for initiation and propagation of stress corrosion cracking, SCC, were investigated with creviced round bar specimens in various concentrations of NaCl solutions at 80°C. After critical potentials for crevice corrosion, ER,CREV, were measured, two types of SCC tests were performed. The specimen was kept at given potential and then the stress of 20kg/mm2 was applied in the Test-1. In the pretreatment in the Test-2, the specimen was kept at a potential higher than ER, CREV to initiate crevice corrosion. After the pretreatment, the specimen was kept at the test potential and the stress of 20kg/mm2 was applied. It was confirmed that ER,CREV is the critical potential for initiation of both crevice corrosion and SCC After SCC initiation condition was determined, stepwise polarization measurement with stress was performed to determine the repassivation potential for the crack propagation, ER,CRACK. The ER,CRACK values were lower than ER,CREV and they became lower with increasing test duration, and reached to the specific value. It indicates that the stress corrosion crack works as severer crevice.

  • 100.
    Skoglund, Sara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Yunda, Elena
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. National Research Tomsk Polytechnic University, Russia.
    Godymchuk, Anna
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. RISE Research Institutes of Sweden.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Difficulties and flaws in performing accurate determinations of zeta potentials of metal nanoparticles in complex solutions-Four case studies2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 7, article id e0181735Article in journal (Refereed)
    Abstract [en]

    The zeta potential (ZP) is a parameter commonly used to characterize metal nanoparticles (NPs) in solution. Such determinations are for example performed in nanotoxicology since the ZP influences e.g. the interaction between cells and different biomolecules. Four case studies on different metal NPs (Cu and Zn NPs, and citrate capped Ag NPs) are presented in this study in order to provide guidance on how to accurately interpret and report ZP data. Solutions of high ionic strength (150 mM NaCl) induce a higher extent of particle agglomeration (elucidated with Ag NPs) when compared with conditions in 10 mM NaCl, which further complicates the prediction of the ZP due to e.g. sedimentation and broadening of the zeta potential distribution. The particle size is seldom included specifically in the standard ways of determining ZP (Huckel and Smoluchowski approximations). However corrections are possible when considering approximations of the Henry function. This was seen to improve the analysis of NPs, since there are cases when both the Huckel and the Smulochowski approximations are invalid. In biomolecule-containing cell media (BEGM), the signal from e.g. proteins may interfere with the measured ZP of the NPs. The intensity distribution of the ZP of both the blank solution and the solution containing NPs should hence be presented in addition to the mean value. Due to an increased ionic strength for dissolving of metal NPs (exemplified by Zn NPs), the released metal ions must be considered when interpreting the zeta potential measurements. In this work the effect was however negligible, as the particle size was several hundred nm, conditions that made the Smoluchowski approximation valid despite an increased ionic strength. However, at low ionic strengths (mM range) and small-sized NPs (tens of nm), the effect of released metal ions can influence the choice of model for determining the zeta potential. Sonication of particle dispersions influences not only the extent of metal release but also the outermost surface oxide composition, which often results in an increased ZP. Surface compositional changes were illustrated for sonicated and non-sonicated Cu NPs. In all, it can be concluded that accurate measurements and interpretations are possible in most cases by collecting and reporting complementary data on characteristics such as particle size, ZP distributions, blank sample information, and particle oxide composition.

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