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  • 1.
    Abitbol, Tiffany
    et al.
    Institute of Materials, School of Engineering, EPFL, 1015 Lausanne, Switzerland;Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Kubat, Mikaela
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Brännvall, Elisabet
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Kotov, Nikolay
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nizamov, Rustem
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Nyberg, Mikael
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Miettunen, Kati
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Nordgren, Niklas
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Stevanic, Jasna S.
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Guerreiro, Maria Pita
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps2023In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 24, p. 21474-21484Article in journal (Refereed)
    Abstract [en]

    From a circular economyperspective, one-pot strategies for theisolation of cellulose nanomaterials at a high yield and with multifunctionalproperties are attractive. Here, the effects of lignin content (bleachedvs unbleached softwood kraft pulp) and sulfuric acid concentrationon the properties of crystalline lignocellulose isolates and theirfilms are explored. Hydrolysis at 58 wt % sulfuric acid resulted inboth cellulose nanocrystals (CNCs) and microcrystalline celluloseat a relatively high yield (>55%), whereas hydrolysis at 64 wt% gaveCNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis weremore polydisperse and had a higher average aspect ratio (1.5-2x),a lower surface charge (2x), and a higher shear viscosity (100-1000x).Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles(NPs) that were <50 nm in diameter and identified as lignin bynanoscale Fourier transform infrared spectroscopy and IR imaging.Chiral nematic self-organization was observed in films from CNCs isolatedat 64 wt % but not from the more heterogeneous CNC qualities producedat 58 wt %. All films degraded to some extent under simulated sunlighttrials, but these effects were less pronounced in lignin-NP-containingfilms, suggesting a protective feature, but the hemicellulose contentand CNC crystallinity may be implicated as well. Finally, heterogeneousCNC compositions obtained at a high yield and with improved resourceefficiency are suggested for specific nanocellulose uses, for instance,as thickeners or reinforcing fillers, representing a step toward thedevelopment of application-tailored CNC grades.

  • 2.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Karimi Aghda, Soheil
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Miljanovic, Danilo J.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Low temperature oxidation behavior of Mo2BC coatings2020In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, no 2, article id 023403Article in journal (Refereed)
    Abstract [en]

    Mo2BC exhibits a unique combination of high stiffness and moderate ductility, enabling the application as a protective and wear resistant coating. As the low temperature oxidation behavior of Mo2BC coatings is unexplored, direct current magnetron sputtered Mo2BC coatings were oxidized at temperatures ranging from 500 to 100 degrees C for up to 28 days. Time-of-flight elastic recoil detection analysis reveals that the onset of oxidation takes place at approximately 300 degrees C as a significant increase in the O content was observed. Crystalline oxide scales containing orthorhombic MoO3 were identified after oxidation for 15 min at 500 degrees C and 10 days at 200 degrees C. Isothermal oxidation at 200 and 100 degrees C exhibits oxide scale thicknesses of 401 +/- 33 and 22 +/- 10 nm after 14 days. Oxidation for 28 days at 100 degrees C exhibits an oxide scale thickness of 13 +/- 3 nm, which is comparable to the aforementioned oxide scale thickness after oxidation for 14 days at 100 degrees C. Based on the combination of mechanical properties and the here reported low temperature oxidation behavior, Mo2BC coatings qualify for applications in solid wood machining and low temperature forming processes at temperatures close to 100 degrees C or below.

  • 3.
    Alhamalawi, Mazen
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Offshore Wind Power Foundations' Corrosion Protection Strategy: Anlysis remotely controlled corrosion protection system and comparison to traditional corrosion protection of offshore wind foundation2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When a metal is surrounded by an electrolyte, such as seawater, a natural potential will be built up. An electron migration between the material and the seawater will happen and the greater the potential difference, the greater the probability that the metal will corrode. Corrosion is an important issue when it comes to offshore structures. In order to achieve a structure designed lifetime, measures can then be taken with regard to capital costs and operating and maintenance costs.

    This study aims to compare the economic advantages and disadvantages of the two, Galvanic Anode Corrosion Protection (GACP) and Impressed Current Cathodic Protection (ICCP), corrosion protection systems on offshore wind power foundations. The first mentioned system uses sacrificial anodes and the second is a cathodic corrosion protection by an applied current.

    The study consisted of several stages of literature studies where theory of corrosion and corrosion systems was used to finally be able to make a comparison between selected corrosion protection systems.

    The result shows that GACP has more advantages and fewer disadvantages than ICCP and would thus be more economical. GACP, for example, is efficient during installation and does not need an additional power source, but ICCP is more complicated and not efficient until complete assembly of the entire system and requires additional power source and cables. Right now, there is no design standard available with detailed requirements and advice has been given as for galvanic anodes systems. 

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  • 4.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tallinn Univ Technol, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Kazemi, S. H.
    Inst Adv Studies Basic Sci, Dept Chem, Zanjan 4513766731, Iran..
    Grossberg-Kuusk, M.
    Tallinn Univ Technol, Dept Mat & Environm Technol, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Kollo, L.
    Odnevall, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Karolinska Inst, AIMES Ctr Advancement Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, SE-17177 Stockholm, Sweden..
    Prashanth, K. G.
    Tallinn Univ Technol, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia.;Austrian Acad Sci, Erich Schmid Inst Mat Sci, Jahnstr 12, A-8700 Leoben, Austria.;Vellore Inst Technol, Sch Mech Engn, CBCMT, Vellore 632014, India..
    Importance of the micro-lattice structure of selective laser melting processed Mo/Mo(x)S(x+1) composite: Corrosion studies on the electrochemical performance in aqueous solutions2022In: Materials Today Chemistry, E-ISSN 2468-5194, Vol. 26, article id 101219Article in journal (Refereed)
    Abstract [en]

    Selective laser melting (SLM) based processing of Mo-based samples is challenging due to solidification cracking. We here demonstrate that the addition of 2 wt% MoS2 to the Mo feedstock markedly improves crack mitigation of SLM-processed Mo/MoS2/Mo2S3 composite micro-lattice structures (SLM-Mo/ Mo(x)S(x+1)). Crack inhibition is suggested to be a result of Mo2S3 formation, decreased lattice strain (0.04 4%), and a decrease in accumulated residual stresses. The increased values of polarization resistance from 42.3 and 19.2 kU cm2 to 437 and 78.2 kU cm2, respectively verified the hindering effect of the composition on stress corrosion cracking (SCC) and surface oxidation cracking. However, an increased corrosion current density, from 1.22 to 10.2 mA/cm2, and cathodic Tafel constant, from 175 to 260.5 mV, confirmed the decreased polarization resistance and occurrence of different types of corrosion such as SCC and pitting. The strategy to add 2 wt% MoS2 to the Mo feedstock enables the fabrication of hightemperature micro-lattice structure components with improved corrosion resistance properties applicable in e.g., electronic, power semiconductor heat sinks, offshore-, aerospace-, defense-, or particularly novel sodium-ion energy storage applications.

  • 5.
    Alipour, Yousef
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Furnace Wall Corrosion in a Wood-fired Boiler2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The use of renewable wood-based fuel has been increasing in the last few decades because it is said to be carbon neutral. However, wood-based fuel, and especially used wood (also known as recycled wood or waste wood), is more corrosive than virgin wood (forest fuel), because of higher amounts of chlorine and heavy metals. These elements increase the corrosion problems at the furnace walls where the oxygen level is low.

    Corrosion mechanisms are usually investigated at the superheaters where the temperature of the material and the oxygen level is higher than at the furnace walls.  Much less work has been performed on furnace wall corrosion in wood or used wood fired boilers, which is the reason for this project.    Tests are also mostly performed under simplified conditions in laboratories, making the results easier to interpret.  In power plants the interpretation is more complicated. Difficulties in the study of corrosion processes are caused by several factors such as deposit composition, flue gas composition, boiler design, and combustion characteristics and so on. Therefore, the laboratory tests should be a complement to the field test ones. This doctoral project involved in-situ testing at the furnace wall of power boilers and may thus contribute to fill the gap.

    The base material for furnace walls is a low alloy steel, usually 16Mo3, and the tubes may be coated or uncoated. Therefore tests were performed both on 16Mo3 and more highly alloyed materials suitable for protective coatings.

    Different types of samples exposed in used-wood fired boilers were analysed by different techniques such as LOM (light optical microscopy), XRD (X-ray diffraction), SEM (scanning electron microscopy), EDS (energy dispersive spectroscopy), WDS (wavelength dispersive spectroscopy), FIB (focused ion beam) and GD-OES (glow discharge optical emission spectroscopy). The corrosion rate was measured. The environment was also thermodynamically modelled by TC (Thermo-Calc ®).

    The results showed that 16Mo3 in the furnace wall region is attacked by HCl, leading to the formation of iron chloride and a simultaneous oxidation of the iron chloride. The iron chloride layer appeared to reach a steady state thickness.  

    Long term exposures showed that A 625 (nickel chromium alloy) and Kanthal APMT (iron-chromium-aluminium alloy) had the lowest corrosion rate (about 25-30% of the rate for 16Mo3), closely followed by 310S (stainless steel), making these alloys suitable for coating materials. It was found that the different alloys were attacked by different species, although they were exposed in the boiler at the same time in the same place. The dominant corrosion process in the A 625 samples seemed to be by a potassium-lead combination, while lead did not attack the APMT samples. Potassium attacked the alumina layer in the APMT samples, leading to the formation of a low-protective aluminate and chlorine was found to attack the base material.  The results showed that stainless steels are attacked by both mechanisms (Cl- induced attack and K-Pb combination).

    Decreasing the temperature of the furnace walls of a waste wood fired boiler could decrease the corrosion rate of 16Mo3. However, this low corrosion rate corresponds to a low final steam pressure of the power plant, which in not beneficial for the electrical efficiency.

    The short term testing results showed that co-firing of sewage sludge with used wood can lead to a reduction in the deposition of K and Cl on the furnace wall during short term testing. This led to corrosion reduction of furnace wall materials and coatings. The alkali chlorides could react with the aluminosilicates in the sludge and be converted to alkali silicates. The chromia layer in A 625 and alumina in APMT were maintained with the addition of sludge. 

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    Thesis
  • 6.
    Alipour, Yousef
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    High temperature corrosion in a biomass-fired power boiler: Reducing furnace wall corrosion in a waste wood-fired power plant with advanced steam data2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The use of waste (or recycled) wood as a fuel in heat and power stations is becoming more widespread in Sweden (and Europe), because it is CO2 neutral with a lower cost than forest fuel. However, it is a heterogeneous fuel with a high amount of chlorine, alkali and heavy metals which causes more corrosion than fossil fuels or forest fuel.

    A part of the boiler which is subjected to a high corrosion risk is the furnace wall (or waterwall) which is formed of tubes welded together. Waterwalls are made of ferritic low-alloyed steels, due to their low price, low stress corrosion cracking risk, high heat transfer properties and low thermal expansion. However, ferritic low alloy steels corrode quickly when burning waste wood in a low NOx environment (i.e. an environment with low oxygen levels to limit the formation of NOx). Apart from pure oxidation two important forms of corrosion mechanisms are thought to occur in waste environments: chlorine corrosion and alkali corrosion.

    Although there is a great interest from plant owners to reduce the costs associated with furnace wall corrosion very little has been reported on wall corrosion in biomass boilers. Also corrosion mechanisms on furnace walls are usually investigated in laboratories, where interpretation of the results is easier. In power plants the interpretation is more complicated. Difficulties in the study of corrosion mechanisms are caused by several factors such as deposit composition, flue gas flow, boiler design, combustion characteristics and flue gas composition. Therefore, the corrosion varies from plant to plant and the laboratory experiments should be complemented with field tests. The present project may thus contribute to fill the power plant corrosion research gap.

    In this work, different kinds of samples (wall deposits, test panel tubes and corrosion probes) from Vattenfall’s Heat and Power plant in Nyköping were analysed. Coated and uncoated samples with different alloys and different times of exposure were studied by scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and light optical microscopy (LOM). The corrosive environment was also simulated by Thermo-Calc software.

    The results showed that a nickel alloy coating can dramatically reduce the corrosion rate. The corrosion rate of the low alloy steel tubes, steel 16Mo3, was linear and the oxide scale non-protective, but the corrosion rate of the nickel-based alloy was probably parabolic and the oxide much more protective. The nickel alloy and stainless steels showed good corrosion protection behavior in the boiler. This indicates that stainless steels could be a good (and less expensive) alternative to nickel-based alloys for protecting furnace walls.

    The nickel alloy coated tubes (and probe samples) were attacked by a potassium-lead combination leading to the formation of non-protective potassium lead chromate. The low alloy steel tubes corroded by chloride attack. Stainless steels were attacked by a combination of chlorides and potassium-lead.

    The Thermo-Calc modelling showed chlorine gas exists at extremely low levels (less than 0.1 ppm) at the tube surface; instead the hydrated form is thermodynamically favoured, i.e. gaseous hydrogen chloride. Consequently chlorine can attack low alloy steels by gaseous hydrogen chloride rather than chlorine gas as previously proposed. This is a smaller molecule than chlorine which could easily diffuse through a defect oxide of the type formed on the steel.

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    Licentiate thesis
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    Abstract-sammanfattning
  • 7.
    Alipour, Yousef
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Reducing furnace wall corrosion by coating the furnace tubes in a waste wood fired boiler plant2012Conference paper (Refereed)
  • 8.
    Alipour, Yousef
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Henderson, Pamela
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Initial Corrosion of Waterwalls Materials in a Waste Wood Fired Power PlantManuscript (preprint) (Other academic)
  • 9.
    Alipour, Yousef
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Henderson, Pamela
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The effect of co-firing of sewage sludge with waste wood on furnace wall corrosion2014In: International Symposium On High-Temperature Oxidation And Corrosion Hakodate, Hokkaido Japan, 2014, 23-27 June, 2014Conference paper (Refereed)
  • 10.
    Alipour, Yousef
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Henderson, Pamela
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Szakalos, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The effect of a nickel alloy coating on the corrosion of furnace wall tubes in a waste wood fired power plant2014In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 65, no 2, p. 217-225Article in journal (Refereed)
    Abstract [en]

    The use of waste wood as a fuel in power plants is becoming more widespread in Europe, because it is a renewable energy source with a lower cost than forest fuel. However it is more corrosive than coal and corrosion problems have arisen in the furnace wall area of a low NOx heat and power boiler. The furnace walls are made of a low alloy steel which has been coated in some parts with a nickel alloy to reduce corrosion. In this work, furnace tubes coated with a nickel alloy were compared to the uncoated tubes of the low alloy steel 16Mo3 after 3 years of exposure in the boiler. The nickel alloy coating and uncoated material were also compared with more controlled testing on a corrosion probe lasting for about 6 weeks. The corrosion rates were measured and the samples were chemically analysed by SEM/EDS/WDS and XRD methods. The corrosive environment was also modelled with Thermo-Calc software. The corrosion rates measured from the probe and tube samples of 16Mo3 agreed well with each other, implying linear corrosion rates. The results also showed that the use of nickel alloy coatings changes the corrosion mechanism, which leads to a dramatic reduction in the corrosion rate. The results are discussed in terms of the corrosion mechanisms and thermodynamic stability of the corrosion products.

  • 11.
    Alipour, Yousef
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Talus, A.
    Henderson, Pamela
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Vattenfall AB, Stockholm 169 92, Sweden.
    Norling, R.
    The effect of co-firing sewage sludge with used wood on the corrosion of an FeCrAl alloy and a nickel-based alloy in the furnace region2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 138, p. 805-813Article in journal (Refereed)
    Abstract [en]

    The effect of digested sewage sludge as a fuel additive to reduce corrosion of furnace walls has been studied. The nickel base alloy Alloy 625 and the iron-chromium-aluminium alloy Kanthal APMT™ were exposed for 14.25. h at the furnace wall in a power boiler burning 100% used (also known as waste or recycled) wood. The test was then repeated with the addition of sewage sludge to the waste wood. The samples were chemically analysed and thermodynamically modelled and the corrosion mechanisms were investigated. The results showed that the co-firing of sewage sludge with recycled wood leads to a reduction in the corrosion. Attack by a potassium-lead combination appeared to be the main corrosion mechanism in Alloy 625 during waste wood combustion, while attack by alkali chloride was found to be dominant in APMT alloy.

  • 12.
    Alipour, Yousef
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Viklund, Peter
    Henderson, Pamela
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler2012In: VGB PowerTech Journal, ISSN 1435-3199, Vol. 92, no 12, p. 96-100Article in journal (Other academic)
    Abstract [en]

    Increasing use is being made of biomass as fuel for electricity production as the price of natural wood continues to rise. Therefore, more use is being made of waste wood (recycled wood). However, waste wood contains more chlorine, zinc and lead, which are believed to increase corrosion rates. Corrosion problems have occurred on the furnace walls of a fluidised bed boiler firing 100 % waste wood under low-NOx conditions. The deposits have been collected and analysed in order to understand the impact of the fuel.

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  • 13.
    Almebäck, Julia Linnea Hildur
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Edberg, Amanda
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Shah, Rafa
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Corrosion in Pulp Mills: Material Selection for an Evaporation Plant2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Corrosion is a global problem which leads to both economicalct on the environment as well as other negative social and ethical aspects. Sodra Cell Monsteras, one of the largest producer of pulp in the world, suffers from corrosion problems in their evaporation plant.

    Problems with corrosion can be handled with an effective material selection process, where suitable materials for specific conditions is discovered. The purpose with this report is to investigate the evaporation plant at Sodra Cell and its specific conditions, including environment and temperature. Also to investigate different types of corrosions common in pulp mills and how these can be prevented, as well as how materials behave under corrosive circumstances. The information is later to be used in a detailed material selection process, which is handled in this report but also should work as a foundation for Sodra Cell Monsteras for future material selections.

    The material selection process in this report is performed according to Ashby's method, with CES Edupack as a supporting tool. The duplex steels, especially EN 1.4485 and EN 1.4362, showed to be the best suitable materials. However, to do a fair judgment and to choose one material, one should do a complete cost efficiency analysis, as well as decide a specific required pitting resistance equivalent number (PREN).

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  • 14.
    Anantha, Krishnan Hariramabadran
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Örnek, Cem
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ejnermark, S.
    Medvedeva, A.
    Sjöström, J.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    In situ AFM study of localized corrosion processes of tempered AISI 420 martensitic stainless steel: Effect of secondary hardening2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 13, p. C810-C818Article in journal (Refereed)
    Abstract [en]

    The effect of secondary hardening of tempered AISI 420 martensitic stainless steel on the corrosion behavior in aqueous 0.01 M NaCl has been studied, in-situ, using atomic force microscopy (AFM) to monitor real-time localized corrosion processes. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses confirmed the presence of undissolved and secondary carbides (Cr23C6, Cr7C3, Cr3C2, Cr3C, Cr2C, and CrC) as well as retained austenite, all finely dispersed in the tempered martensitic matrix. Electrochemical measurements, consisted of monitoring of the open-circuit potential vs. time and cyclic polarization in 0.01 M NaCl solution, were performed to evaluate the passivity and its breakdown, and it was seen that initiation sites for localized corrosion were predominantly peripheral sites of carbides. In-situ AFM measurements revealed that there was a sequence for localized corrosion in which the neighboring matrix next to secondary carbides dissolved first, followed by corrosive attack on regions adjacent to undissolved carbides. Tempering at 500◦C reduced the corrosion resistance and the ability to passivate in comparison to tempering at 250◦C.

  • 15.
    Anantha, Krishnan Hariramabadran
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Örnek, Cem
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ejnermark, Sebastian
    Uddeholms AB, Res & Dev, SE-68385 Hagfors, Sweden..
    Thuvander, Anders
    Uddeholms AB, Res & Dev, SE-68385 Hagfors, Sweden..
    Medvedeva, Anna
    Uddeholms AB, Res & Dev, SE-68385 Hagfors, Sweden..
    Sjostrom, Johnny
    Uddeholms AB, Res & Dev, SE-68385 Hagfors, Sweden..
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Experimental and modelling study of the effect of tempering on the susceptibility to environment-assisted cracking of AISI 420 martensitic stainless steel2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 148, p. 83-93Article in journal (Refereed)
    Abstract [en]

    The resistance to environment-assisted cracking (EAC) of AISI 420 martensitic stainless steel (MSS) was investigated in 0.3 M NaCl solution (room temperature) at constant loads for 30 days. The steel tempered at 250 degrees C was superior to the 500 degrees C-temper, which showed corrosion pits favouring cracking. The fracture surface showed faceted grains, cleavage, striations, and inter- and transgranular cracks, suggesting a mixed stress corrosion cracking (SCC) and hydrogen embrittlement (HE) mechanism as the cause for EAC. Finite element modelling (FEM) indicated strain/stress localization at the mouth of deep pits and at the wall of shallow pits, displaying the favoured locations for pit-to-crack transition.

  • 16.
    Andersson, Albin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    A novel chitosan-stearic coating with bee-pollen microcapsules for corrosion protection2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this project a novel chitosan-stearic acid (CS-SA) coating with bee-pollen microcapsules for encapsulation of 2-mecraptobenzothiazole (MBT) as a waterborne formulation for a biocompatible corrosion protection coating was developed and the coating properties was analyzed. Hydrophobic stearic acid (SA) was crosslinked with via a carbodiimide reaction to form micelles and is assembled on the bee- pollen grains and the chitosan matrix was further self-crosslinked using glutaraldehyde (GA). Stearic acid was used to hydrophobically interact with modified pollen and with further crosslinking with the chitosan, which was proven successful by FTIR results. The encapsulation of anticorrosive agent MBT into pollen was successful and examined by UV-Vis spectroscopy, however, the pollen cannot form a fully stable formulation with the chitosan micelle matrix, partially due to its relatively big size (ca. 20 μm), causing problems with forming a proper barrier protection. The size of the grains and the interference of the carbodiimide crosslinking is the most severe problems with the pollen microcapsules. Therefore, no further testing of the corrosive properties could be done, which requires a dense and stable coating to sustain in salty water for the whole measurement period. As the reference coatings without pollen provided much more promising results, especially when crosslinked with GA, the conclusion is that the reactivity of the pollen is proven difficult to crosslink, and choosing a proper size of a microcontainer and the appropriate encapsulation method in the binder matrix is vital and important for developing a corrosion protective coating.

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  • 17.
    Andersson, Jennifer
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Inledande utvärdering av epoxibaserad livstidsförlängning av fjärrvärmerör: Relining av kolstål med en polyamidhärdande lösningsmedelsfri epoxi2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Degradation of steel pipes in district heating systems is often a result of corrosion processes. To maintain the power in the systems the pipes gets replaced when they have been worn-out, resulting in high cost and long service time due to excavation. A more affordable and time- effective method is known to be relining which implies renovation and facing of the already existing pipes. This thesis covers an initial review of the applicability of a polyamide curing solvent-free epoxy based relining for lifetime extension of corroded pipes in Stockholm Exergi's pipeline network. The research study is comprised of a literature search focusing on the permeability properties of epoxy coatings, an experimental part where the actual coating was tested for defined parameters similar to the prevailing ones in the system of Stockholm Exergi and finally an evaluation of the usability of the coating. Critical parameters such as the adhesion between the coating and the steel substrate, the sorption of water within the coating and the emit of Bisphenol A were carefully investigated during the analysis. Analysis methods such as pull of test, TGA, DSC and GC-MS were utilized in order to investigate the critical parameters. The adhesion between the coating and the substrate was found to be inadequate for the purpose, the TGA and DSC analysis showed a time-dependent increasing water sorption when exposure to 120 °C. At a higher temperature of 190 °C the sorption decreased. It was concluded that the coating cured at higher exposure temperatures which implied higher degree of conversion and thus a more brittle epoxy matrix. Additionally, the hydrophobicity decreased during 28 days of exposure, at both 120 °C and 190 °C, which can be supposed to affect the flow in the pipeline system during service. It can be stated that a spray coating consisting a polyamide curing solvent-free epoxy will not answer to a total solution for a lifetime extension for the pipes in Stockholm Exergi's pipeline network. An extended investigation regarding the exterior isolation of the pipes is suggested in order to circumvent the most critical breakdowns due to corrosion.

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    Inledande utvärdering av epoxibaserad livstidsförlängning av fjärrvärmerör
  • 18.
    Andersson, Simon
    et al.
    IVL Swedish Environmental Research Institute.
    Gottfridsson, Marie
    IVL Swedish Environmental Research Institute.
    LCA of zinc phosphating and thin film pre-treatment2023Report (Other academic)
    Abstract [en]

    LCA of zinc phosphating and thin film pre-treatment.

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  • 19. Antikhovich, I. V.
    et al.
    Kharitonov, Dima S.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Belarusian State Technological University, Belarus.
    Chernik, A. A.
    Dobryden, Illia B.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Corrosion Resistance of Nickel Coatings Deposited from Low-Temperature Nickel-Plating Electrolytes2017In: Russian journal of applied chemistry, ISSN 1070-4272, E-ISSN 1608-3296, Vol. 90, no 4, p. 566-573Article in journal (Refereed)
    Abstract [en]

    The corrosion resistance of nickel coatings on a copper substrate, plated from low-temperature electrolytes based on acetates, tartrates, and isobutyrates, was studied by the methods of electrochemical impedance spectroscopy (EIS) and polarization curves. The tests were performed in a 0.3% NaCl solution. The nickel coatings exhibit high chemical activity, dissolving in the NaCl solution. The electrochemical step is the limiting step of the corrosion process.

  • 20.
    Armani, Alessandro
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Development of corrosion resistant coatings using natural biopolymer and pollen2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Corrosion is a mechanism that highly reduces the lifetime of metals in different environments, especially in water or moisture environment. The worldwide maintenance cost due to corrosion is estimated in billions of dollars per year, and actual solutions in terms of coating usually contains toxic or environmentally harmful species. With an always increasing restriction by environmental restraints and regulations, a sustainable solution is urgently needed.

    Chitosan, easily obtained from chitin, the second most abundant biopolymer on earth, can be the solution to many problems. Crustacean shell waste is one of the major sources of chitin. Its resource efficiency, biocompatibility, and versatile physicochemical properties for chelation and crosslinking make chitosan a promising candidate as matrix material for biobased anticorrosive application.

    The purpose of the Master Thesis is to combine the properties of chitosan with the high porosity of bee pollen as anticorrosive agent carrier to obtain a fully sustainable solution for anticorrosive protection. The objective of this very ambitious project is to produce a composite material with a triple action: anticorrosive protection of metal surfaces, self-healing property of the coating and anti- biofouling activity.

    Results show that a biopolymer composite in forms of suspension or coatings with all desired components could be achieve. Specifically, a biopolymer nanocomposite composed of chitosan matrix, embedded with pollen grains that were loaded with anticorrosion agent 2- mercatobenzothiazole (MBT) in advance, and with zinc oxide nanoparticles have been produced.

    The physicochemical characterization of the biopolymer composite and its coatings, as well as electrochemical impedance spectroscopy (EIS) measurements on stainless steel plate with such coatings, suggest that a uniform and compact coating is obtained. Despite its good hydrophobicity with maximum contact angle 134.32 ± 3.84° with top coating, the chitosan nanocomposite coating is still permeable to water, partially because of the relatively big size of pollen (ca. 20 μm) that introduces gaps and interferes integrity of the coating. Therefore, a full immersion corrosion resistance is not achieved. In conclusion, phase transfer of hydrophobic pollen into hydrophilic chitosan matrix, MBT loading in pollen, ZnO encapsulation in chitosan, as well as crosslinking of chitosan, were successfully carried out. A coating based on such biopolymer nanocomposite is prepared on stainless steel and investigated on its anti-corrosion property. Future work will be choosing a proper sized pollen as a microcontainer to enhance the integrity of the coating, and eventually endow the coating with the three-in-one function, i.e., anticorrosion, antimicrobial, and self-healing.

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  • 21.
    Atapour, Masoud
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Stainless steel in simulated milk and whey protein solutions - Influence of grade on corrosion and metal release2020In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 331, article id 135428Article in journal (Refereed)
    Abstract [en]

    Reactions at the biointerfaces between stainless steel and protein-rich dairy products, which contain whey proteins, are important to consider in terms of food safety and material grade selection. Changes in corrosion behavior, metal release, and surface composition of austenitic (AISI 316 L), ferritic (AISI 430), and lean duplex (LDX 2101) stainless steels in simulated milk (SMS) and whey protein solution were investigated. The amount of released metals and the corrosion susceptibility increased according to 2101 < 316 L < 430. All grades revealed low corrosion rates in the whey protein solution without any sign of active/metastable corrosion. Pitting corrosion was evident for 430 in SMS. The total amount of released metals (iron, chromium, and nickel) was significantly higher in whey protein solution compared with SMS. This suggests the metal release process to be mainly governed by complexation reactions. Nickel was preferentially released compared to its bulk composition fraction for both 316 L and 2101 in the highly complexing SMS. Reduced metal release rates with time correlated with the enrichment of chromium in the surface oxide. The extent of metal release was for all metals substantially lower than release limits of metals stipulated in health regulations related to the use of alloys and metals in food-related environments.

  • 22.
    Atapour, Masoud
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chaudhary, Himanshu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Lendel, Christofer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions2019In: Food Control, ISSN 0956-7135, E-ISSN 1873-7129, Vol. 101, p. 163-172Article in journal (Refereed)
    Abstract [en]

    Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 hat room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks.

  • 23.
    Bae, Kichang
    et al.
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Shin, Dongmin
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Lee, Jonghun
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Kim, Seohan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Lee, Wookjin
    Pusan Natl Univ, Sch Mat Sci & Engn, Busan 46241, South Korea..
    Jo, Ilguk
    Dong Eui Univ, Adv Mat Engn, Busan 47340, South Korea..
    Lee, Junghoon
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Corrosion Resistance of Laser Powder Bed Fused AISI 316L Stainless Steel and Effect of Direct Annealing2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 18, article id 6336Article in journal (Refereed)
    Abstract [en]

    Alloy parts produced by an additive manufacturing method with rapid heat transfer from fast melting and solidification have different microstructures, characteristics, and performances compared with materials made by the conventional process. In this study, the corrosion and oxidation resistance of SS316L, which was prepared by the powder bed fusion process, was compared with those of cold-rolled SS316L. Additionally, the surface oxide film on stainless steel was thoroughly assessed since the film has the greatest influence on the corrosion and oxidation resistance. The effect of heat treatment on corrosion and oxidation resistance of SS316L fabricated by additive manufacturing was investigated. The SS316L has a microstructure formed by sub-grain cells, in which locally concentrated alloying elements form a stable passive film. As a result, it has a higher level of corrosion resistance and oxidation resistance than conventional cold-rolled materials. However, it was confirmed that the sub-grain cell was removed by heat treatment, which resulted in the degradation of corrosion and oxidation resistance.

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  • 24.
    Bakhit, Babak
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Dorri, Samira
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Kosari, Ali
    Delft Univ Technol, Netherlands.
    Mol, Arjan
    Delft Univ Technol, Netherlands.
    Petrov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci & Technol, Taiwan.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Microstructure, mechanical, and corrosion properties of Zr1-xCrxBy diboride alloy thin films grown by hybrid high power impulse/DC magnetron co-sputtering2022In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 591, article id 153164Article in journal (Refereed)
    Abstract [en]

    We study microstructure, mechanical, and corrosion properties of Zr1-xCrxBy coatings deposited by hybrid high power impulse/DC magnetron co-sputtering (CrB2-HiPIMS/ZrB2-DCMS). Cr/(Zr + Cr) ratio, x, increases from 0.13 to 0.9, while B/(Zr + Cr) ratio, y, decreases from 2.92 to 1.81. As reference, ZrB2.18 and CrB1.81 layers are grown at 4000 W DCMS. ZrB2.18 and CrB1.81 columns are continual from near substrate toward the surface with open column boundaries. We find that the critical growth parameter to achieve dense films is the ratio of Cr+- dominated ion flux and the (Zr + B) neutral flux from the ZrB2 target. Thus, the alloys are categorized in two groups: films with x &lt; 0.32 (low Cr+/(Zr + B) ratios) that have continuous columnar growth, rough surfaces, and open column boundaries, and films with x &gt;= 0.32 (high Cr+/(Zr + B) ratios) that Cr+-dominated ion fluxes are sufficient to interrupt continuous columns, resulting in smooth surface and dense fine-grain microstructure. The pulsed metal-ion irradiation is more effective in film densification than continuous Ar+ bombardment. Dense Zr0.46Cr0.54B2.40 and Zr0.10Cr0.90B1.81 alloys are hard (&gt; 30 GPa) and almost stress-free with relative nano indentation toughness of 1.3 MPa root m and 2.3 MPa root m, respectively, and remarkedly low corrosion rates (~& nbsp;1.0 x 10(-6) mA/cm(2) for Zr0.46Cr0.54B2.40 and~& nbsp; 2.1 x 10(-6) mA/cm(2) for Zr0.10Cr0.90B1.81).

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  • 25.
    Baysal, Mustafa
    et al.
    Sabanci Univ, Turkey.
    Bilge, Kaan
    Sabanci Univ, Turkey; Imperial Coll London, England.
    Yildizhan, Melike
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Sabanci Univ, Turkey.
    Yorulmaz, Yelda
    Sabanci Univ, Turkey.
    Oncel, Cinar
    Mugla Sitki Kocaman Univ, Turkey.
    Papila, Melih
    Sabanci Univ, Turkey.
    Yurum, Yuda
    Sabanci Univ, Turkey.
    Catalytic synthesis of boron nitride nanotubes at low temperatures2018In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, no 10, p. 4658-4662Article in journal (Refereed)
    Abstract [en]

    KFeO2 is demonstrated to be an efficient catalyst for the formation of boron nitride nanotubes (BNNT) by thermal chemical vapor deposition (TCVD). This alkali-based catalyst enables the formation of crystalline, multi-walled BNNTs with high aspect ratio at temperatures as low as 750 degrees C, significantly lower than those typically required for the product formation by TCVD.

  • 26.
    Beldowski, Piotr
    et al.
    UTP Univ Sci & Technol, Inst Math & Phys, Al Kaliskiego 7, PL-85796 Bydgoszcz, Poland..
    Weber, Piotr
    Gdansk Univ Technol, Atom & Opt Phys Div, Dept Atom Mol & Opt Phys, Fac Appl Phys & Math, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Dédinaité, Andra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Box 5607, SE-11486 Stockholm, Sweden..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Box 5607, SE-11486 Stockholm, Sweden..
    Gadomski, Adam
    UTP Univ Sci & Technol, Inst Math & Phys, Al Kaliskiego 7, PL-85796 Bydgoszcz, Poland..
    Physical crosslinking of hyaluronic acid in the presence of phospholipids in an aqueous nano-environment2018In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 14, no 44, p. 8997-9004Article in journal (Refereed)
    Abstract [en]

    Hyaluronic acid and phospholipids are two components in the synovial joint cavity that contribute to joint lubrication synergistically. Molecular dynamics simulations were performed and hydrogen bonds in hyaluronic acid were analyzed to identify specific sites that are responsible for its physical cross-linking. Two molecular masses of hyaluronic acid, 10 kDa and 160 kDa, were considered. We use molecular dynamics simulations and the small world network approach to investigate dynamic couplings using a distance map applied to oxygen atoms in a chain of hyaluronic acid in the presence of phospholipids and water. The distance characterizing the coupling can be defined in various ways to bring out the most evident differences between various scenarios of the polymer chain conformation We show herein a physical distance understood as H-bond length and classes of these distances which are defined in a coarse-grained picture of the molecule. Simulation results indicate that addition of phospholipids has little influence on hyaluronic acid crosslinking. However, longer chains and addition of lipids promote appreciably long lasting (resilient) networks that may be of importance in biological systems. Specific sites for hydrogen bonding of phospholipids to hyaluronic acid have also been identified.

  • 27.
    Belonoshko, Anatoly B.
    et al.
    KTH, Superseded Departments (pre-2005), Physics.
    Rosengren, Anders
    KTH, Superseded Departments (pre-2005), Physics.
    Dong, Qian
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Hultquist, Gunnar
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    Leygraf, Christofer
    KTH, Superseded Departments (pre-2005), Materials Science and Engineering.
    First-principles study of hydrogen diffusion in α-Al 2O3 and liquid alumina2004In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 69, no 2, p. 243021-243026Article in journal (Refereed)
    Abstract [en]

    We have studied the energetics and mobility of neutral hydrogen in alumina Al2O3 using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum (α-Al2O 3) as well as in liquid alumina. Using both static as well as molecular-dynamics calculations, and applying classical transition state theory, we derive the temperature-dependent diffusivity of hydrogen in α-Al 2O3 as D(T)=(21.7 × 10-8 m 2/s)exp(-1.24 eV/kT). The corresponding diffusivity of hydrogen in liquid/amorphous alumina, derived directly from ab initio molecular dynamics calculations, is D(T)=(8.71 × 10-7 m2/s)exp(-0.91 eV/kT). The computed diffusivity compares very well to experimental data. We conclude that diffusion of neutral hydrogen through the bulk of alumina is a good approximation of the mechanism for hydrogen mobility in corrosion scales. The representation of grain-boundary structures by amorphous alumina is, probably, realistic at higher temperatures.

  • 28. Bender, R.
    et al.
    Féron, D.
    Mills, D.
    Ritter, S.
    Bäßler, R.
    Bettge, D.
    De Graeve, I.
    Dugstad, A.
    Grassini, S.
    Hack, T.
    Halama, M.
    Han, E. -H
    Harder, T.
    Hinds, G.
    Kittel, J.
    Krieg, R.
    Leygraf, Christopher
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Martinelli, L.
    Mol, A.
    Neff, D.
    Nilsson, J. -O
    Odnevall, Inger
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Paterson, S.
    Paul, S.
    Prošek, T.
    Raupach, M.
    Revilla, R. I.
    Ropital, F.
    Schweigart, H.
    Szala, E.
    Terryn, H.
    Tidblad, J.
    Virtanen, S.
    Volovitch, P.
    Watkinson, D.
    Wilms, M.
    Winning, G.
    Zheludkevich, M.
    Corrosion challenges towards a sustainable society2022In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 73, no 11, p. 1730-1751Article in journal (Refereed)
    Abstract [en]

    A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate-resilient energy systems and infrastructures brings with it a long-term direction, so as a result the long-term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics. 

  • 29.
    Bender, R.
    et al.
    DECHEMA eV, Germany.
    Tidblad, Johan
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Zheludkevich, M.
    Helmholtz-Zentrum Hereon, Germany.
    Corrosion challenges towards a sustainable society2022In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 73, no 11, p. 1730-1751Article in journal (Refereed)
    Abstract [en]

    A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate-resilient energy systems and infrastructures brings with it a long-term direction, so as a result the long-term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics. © 2022 The Authors. 

  • 30.
    Bengtsson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Investigation of Galvanic Corrosion between Graphite Gaskets and Stainless Steel Flanges2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At Forsmark, several cases of suspected galvanic corrosion have been detected and

    believed to be caused by an inappropriate use of graphite gaskets in brackish water.

    This report studies the likelihood of galvanic corrosion between the graphite gasket

    and stainless steels and aims to be a reference when investigating galvanic corrosion in

    the future. To evaluate galvanic corrosion, several electrochemical experiments were

    studied, such as galvanic series, polarization curves, and galvanic current

    measurements with a ZRA.

    The electrochemical results showed that when immersing the stainless steel (254

    SMO) and the graphite gasket (Novatec) into brackish water, there was a current

    flowing between the electrodes. However, the current was very small, which could be

    explained by the protection from a passive film on the stainless steel. The difference

    in corrosion potential between the two materials was measured and compared to

    results from polarization curves. It appeared that 254 SMO would be protected by a

    passive film at the measured potential. Galvanic current measurements also indicated

    the presence of a passive film under the investigated conditions.

    The results indicate that galvanic corrosion itself should not have caused the

    corrosion attacks at Forsmark. The found corrosion is more likely due to crevice

    corrosion that was accelerated by the combination of a crevice, a welded flange

    surface, chlorides in water and possibly a graphite gasket.

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  • 31.
    Berendson, Jaak
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Electrochemical methods2007In: Surface Characterization: A User's Sourcebook, Wiley-Blackwell, 2007, p. 590-606Chapter in book (Other academic)
  • 32.
    Bettini, Eleonora
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Influence of carbides and nitrides on corrosion initiation of advanced alloys: A local probing study2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Advanced alloys often present precipitated carbides and nitrides in their microstructure following exposure to elevated temperatures. These secondary phases are usually undesirable, because potentially deleterious for the corrosion and mechanical performances of the material. Carbides and nitrides are enriched in key alloying elements that are subtracted from their surrounding matrix areas, creating alloying element depleted zones, which might become initial sites for corrosion initiation. In this study, the influence of micro- and nano-sized precipitated carbides and nitrides on the corrosion initiation of biomedical CoCrMo alloys and duplex stainless steels has been investigated at microscopic scale, by using a combination of local probing techniques. The microstructures of the alloys were first characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and magnetic force microscopy (MFM). The Volta potential mapping of carbides and nitrides revealed their higher nobility compared to the matrix, and particularly compared to their surrounding areas, suggesting the occurrence of some alloying element depletion in the latter locations, which may lead to a higher susceptibility for corrosion initiation. In-situ electrochemical AFM studies performed at room temperature showed passive behavior for large potential ranges for both alloy families, despite the presence of the precipitated carbides or nitrides. At high anodic applied potential, at which transpassive dissolution occurs, preferential dissolution started from the areas adjacent to the precipitated carbides and nitrides, in accordance with the Volta potential results. Thus, the presence of carbides and nitrides doesn’t largely affect the corrosion resistance of the tested advanced alloys, which maintain passive behavior when exposed to highly concentrated chloride solutions at room temperature with no applied potential. The effect of nitrides on the corrosion initiation of duplex stainless steels was investigated also at temperatures above the critical pitting temperature (CPT). Depending on the type, distribution and size range of the precipitated nitrides different corrosion behaviors were observed. Intragranular (quenched-in) nano-sized nitrides (ca. 50-100 nm) finely dispersed in the ferrite grains have a minor influence on the corrosion resistance of the material at temperatures above the CPT, while larger intergranular (isothermal) nitrides (ca. 80-250 nm) precipitated along the phase boundaries cause a detrimental reduction of the corrosion resistance of the material, in particular of the austenite phase

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  • 33.
    Bettini, Eleonora
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kivisäkk, Ulf
    Sandvik Materials Technology.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Study of corrosion behavior of a 22% Cr duplex stainless steel: influence of nano-sized chromium nitrides and exposure temperature2013In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 113, p. 280-289Article in journal (Refereed)
    Abstract [en]

    Chromium nitrides may precipitate in duplex stainless steels during processing and their influence on the corrosion behavior is of great importance for the steel performance. In this study, the influence of nano-sized quenched-in chromium nitrides on the corrosion behavior of a heat treated 2205 duplex stainless steel was investigated at room temperature and 50 °C (just above critical pitting temperature). The microstructure was characterized by SEM/EDS and AFM analyses, and quenched-in nitrides precipitated in the ferrite phase were identified by TEM analysis. Volta potential mapping at room temperature suggests lower relative nobility of the ferrite matrix. Electrochemical polarization and in-situ AFM measurements in 1 M NaCl solution at room temperature show a passive behavior of the steel despite the presence of the quenched-in nitrides in the ferrite phase, and preferential dissolution of ferrite phase occurred only at transpassive conditions. At 50 °C, selective dissolution of the austenite phase was observed, while the ferrite phase with the quenched-in nitrides remained to be stable. It can be concluded that the finely dispersed quenched-in nitrides do not cause localized corrosion, whereas the exposure temperature has a strong influence on the corrosion behavior of the duplex stainless steel.

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    Paper 4
  • 34.
    Bettini, Eleonora
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kivisäkk, Ulf
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Study of Corrosion Behavior of a 2507 Super Duplex Stainless Steel: Influence of Quenched-in and Isothermal Nitrides2014In: International Journal of Electrochemical Science, E-ISSN 1452-3981, Vol. 9, no 1, p. 61-80Article in journal (Refereed)
    Abstract [en]

    Precipitation of different types of chromium nitrides may occur during processing of super duplex stainless steels, affecting the properties of the material. In this study the influence of quenched-in (size range ca. 50-100 nm) and isothermal (size range ca. 80-250 nm) types of nitrides on the corrosion behavior of a 2507 super duplex stainless steel has been investigated at room temperature and at 90 degrees C (above the critical pitting temperature) in 1 M NaCl solution. The microstructure has been characterized by scanning electron microscopy and magnetic force microscopy. The isothermal nitrides exhibit a higher Volta potential compared to the matrix, but such difference could not be observed for the quenched-in nitrides. In-situ electrochemical AFM measurements at room temperature show stable surfaces for a wide range of applied potentials despite the presence of either type of nitrides. In the transpassive region isothermal nitrides appear to be slightly more deleterious than quenched-in nitrides. At 90 degrees C isothermal nitrides largely reduce the corrosion resistance of the austenite phase, while the quenched-in nitrides reduce the corrosion resistance of the material to a much lesser extent. The size difference between isothermal and quenched-in chromium nitrides may be crucial, in particular above the critical pitting temperature.

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    Paper 5
  • 35.
    Bettini, Eleonora
    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.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Nature of current increase for a CoCrMo alloy: "transpassive" dissolution vs. water oxidation2013In: International Journal of Electrochemical Science, E-ISSN 1452-3981, Vol. 8, no 10, p. 11791-11804Article in journal (Refereed)
    Abstract [en]

    The “transpassive” behavior of a CoCrMo alloy has been investigated to clarify the nature of the current increase at high anodic potential (0.5-0.7 VAg/AgCl). The total amount of released metal ions was determined after the potentiostatic measurements. According to the calculation through Faradays’ law, the metal dissolution only contributes to part of the total current recorded. Electrochemical AFM mapping did not show pronounced topography changes at 0.65 VAg/AgCl, while light optical microscopy observation revealed fast evolution of oxygen bubbles. Evidently water oxidation is another important process largely contributing to the current increase at the high potential.

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    Paper 3
  • 36.
    Bexell, Ulf
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Engkvist, Josefin
    Chalmers University of Technology, Göteborg, Sweden.
    Malmberg, Per
    Chalmers University of Technology, Göteborg, Sweden.
    Comparing 69Ga+ and C60+ for ToF-SIMS sputter depth profiling in a Cr2O3 formed during oxidation of a Ce coated FeCr steel substrate2012Conference paper (Other academic)
  • 37. Bełdowski, P.
    et al.
    Weber, P.
    Dédinaité, Andra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden.
    Gadomski, A.
    Correction: Physical crosslinking of hyaluronic acid in the presence of phospholipids in an aqueous nano-environment (Soft Matter (2018) DOI: 10.1039/c8sm01388h)2018In: Soft Matter, ISSN 1744-683X, Vol. 14, no 47Article in journal (Refereed)
    Abstract [en]

    Correction for 'Physical crosslinking of hyaluronic acid in the presence of phospholipids in an aqueous nano-environment' by Piotr Bełdowski et al., Soft Matter, 2018, DOI: 10.1039/c8sm01388h. 

  • 38.
    Björlenstam, Philip
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Evaluation of corrosion in crevices in screw joints2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this Master of Science thesis screws with different coatings were exposed to an accelerated corrosion test in order to investigate the corrosion development. The test matrix constituted of hexagonal and flange screws (fastened on frames) coated with either zinc/iron (ZnFe) or a flake system of aluminum and zinc (GEOMET). The corrosion results were analyzed by means of X-ray diffraction (XRD). In this study the screws were also crosscut and analyzed by means of FEG-SEM in order to determine the thickness and the elemental content of the surface coating. The result of the corrosion test showed that the screws coated with GEOMET showed a very good corrosion resistance whilst the screws coated with ZnFe failed to fulfill the demands on corrosion resistance of Scania.

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    fulltext
  • 39.
    Bonin, Pierre
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Corrosion. Université de Toulouse, France.
    Roggero, Aurelien
    Université de Toulouse, France.
    Caussé, Nicolas
    Université de Toulouse, France.
    Pébère, Nadine
    Université de Toulouse, France.
    Thierry, Dominique
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Le Bozec, Natalie
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Impedance analysis of the barrier effect of coil-coated materials: Water uptake and glass transition variations2021In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 153, article id 106163Article in journal (Refereed)
    Abstract [en]

    In the present work, an industrial polyester coil-coated steel sample was characterized by electrochemical impedance spectroscopy. The diagrams were obtained for various immersion times in a 0.5 M NaCl solution for three different initial states of the same coil coating (as received, dried and dried after the impedance measurements). The aim of the study was to have a better knowledge of how the water uptake influences the coil coating physical properties and to extract relevant parameters of the ageing processes. From the high-frequency part of the impedance diagrams, the water uptake was calculated using a linear rule of mixtures. Two sorption regions were observed for the dried samples suggesting the presence of porosities already filled with ambient moisture for the as-received sample. It was shown that the water uptake was a slow process and, independently of the initial state of the sample, a saturation plateau was never reached, even after 456 h of immersion. A time constant, clearly visible on the phase angle of the impedance diagrams, was analysed through the dielectric permittivity formalism and attributed to the signature of the dielectric manifestation of the glass transition. This time constant was shifted to higher frequencies with increasing water fraction (increasing immersion time), consistent with a plasticization effect. This result was supported by differential scanning calorimetry measurements. Finally, the data obtained for the different initial states of the coating highlighted that, even if the water uptake was reversible, the sorption kinetics was different for the sample dried after the impedance measurements. This could be of importance in the degradation process of the coil coated steel. 

  • 40.
    Boubitsas, Dimitrios
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB, Betong & Berg. Lund University, Sweden.
    Chloride transport and chloride threshold values: studies on concretes and mortars with Portland cement and limestone blended cement2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reinforced concrete is one of the most widely used building materials and if it is properly designed and produced, it is an extremely durable material with a service life up to 100 years. However, under certain environmental conditions the service life of reinforced concrete structures is more limited. Deterioration ofconcrete structure is in most cases caused by the penetration of aggressive media from the surrounding environment. Chloride initiated reinforcement corrosion is one of the major causes of deterioration of Concrete structures. One conflicting issue is how replacing Portland cement with mineral additions influences chlorideinitiated reinforcement corrosion. This issue is of immediate interest, as there is a steady growth in the use of cement blended with mineral additions, such as blast-furnace slag, fly ash and limestone filler. This is done by the cement and concrete industry to reduce the CO2 emissions linked to Portland cement manufacturing, bylimiting the use of clinker in the cement.The main objective of this work has been to further clarify the role of limestone filler as partial substitute to Portland cement on the two main decisive parameters for chloride induced reinforcement corrosion: chloride ingress rate and chloride threshold values. In the first part of this work the chloride ingress was studied both with accelerated laboratory methods and also after field exposure. The initial focus for the second part of the study was to determine the chloride threshold values for the binders investigated in the first part, so a comprehensive view of the effect of limestone addition on chloride initiated corrosion could be presented.However, during the work the need for the development of a practice-related method for determining the chloride threshold values was identified and the focus of the research was redirected to meet that need.The efficiency of limestone filler concerning chloride ingress showed to be dependent on replacement ratio, time (age) and on the test method. It was not possible to draw any rigid conclusion of the limestone filler’s efficiency regarding chloride ingress. But part of the inconsistency in the results was identified to be that limestone filler has two opposite effects on chloride ingress, on one hand contribute to a refinement of microstructure and on the other hand diminishing the chloride binding.The steel surface condition was shown to have a strong effect on the corrosion initiation, and can likely be one of the most decisive parameters attributing to the variability in the reported chloride threshold values obtained in laboratory experiments. The chloride threshold value for the sulphate resistant Portland cement fromthe laboratory experiments was estimated to be about 1% by weight of binder. For the concrete with limestone blended cement (CEM II/A-LL 42.5R) tested in this work the chloride threshold value was at the same level as for the sulphate resistant Portland cement. From the field study but with a somewhat different definition ofchloride threshold value, a chloride threshold value of about 1% by weight of binder was also estimated for ordinary Portland cement and sulphate resistance Portland with 5% silica fume exposed to marine environment.

  • 41.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Enestam, Sonja
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Mäkelä, Kari
    Condensation in the KCl–NaCl system2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 105, p. 142-148Article in journal (Refereed)
    Abstract [en]

    Condensation of gaseous KCl and NaCl is known to participate in deposit formation and high temperature corrosion processes in heat and power plants. Little is known about interaction between the two salts, which is of interest for the overall understanding of deposit and corrosion problems. Within this study, condensation at different material surface temperatures and salt mixtures was investigated.

    Salt vapors were prepared by temperature controlled evaporation. A cooled condensation probe with a temperature gradient was inserted in the hot gas. After exposure, the probe surface was visually inspected and analyzed with SEM/EDS and XRD for elemental and phase composition. TGA/DTA was used to provide complementary information on vaporization and sintering.

    The results indicated that a mixture of KCl and NaCl probably condenses as separate phases at concentrations and temperatures below the melting points of the salts. Condensation was possibly followed by a secondary sintering process. It was verified by TGA/DTA that a mixture of solid KCl and NaCl particles sinters and melts rapidly at temperatures above the melting temperature of a corresponding solution. It was also seen that sintering took place at lower temperatures with slow solid-gas interactions, possibly with the formation of solid solutions.

  • 42.
    Bulidon, Nicolas
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Pélissier, Krystel
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Boissy, Clément
    M.E.C.M Rond-point de l'échangeur, France.
    Mendibide, Christophe
    RISE Research Institutes of Sweden, Materials and Production, Corrosion.
    Maillot, Valérie
    Andra, France.
    Bourbon, Xavier
    Andra, France.
    Crusset, Didier
    Andra, France.
    Hydrogen production through aluminium corrosion in a cement-based matrix2023In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 74, no 11-12, p. 1765-1776Article in journal (Refereed)
    Abstract [en]

    In France, deep geological disposal is considered for the storage of high and intermediate-level long-lived radioactive wastes. For aluminium, the possibility to encapsulate the wastes in a cement-based matrix is studied. However, cement being an alkaline environment, aluminium can lose its passivity, starts to corrode leading to hydrogen evolution in the infrastructures and generate a possible explosive hazard after decades of storage if hydrogen can accumulate somewhere in the facility. It is therefore necessary to study the corrosion behaviour of aluminium in the different cements considered for the encapsulation to estimate the possible amount of hydrogen that could be generated through corrosion and design the cement capsules accordingly. This work mainly focused on the reaction occurring at the aluminium-cement interface. Raman spectroscopy did not highlight significant differences in the nature of the corrosion products forming at the cement/aluminium interface, leading to the conclusion that it is not the chemistry of the cement that is the key factor controlling the corrosion rate but rather the physical properties of the cement matrix. 

  • 43.
    Caussé, Nicolas
    et al.
    Université de Toulouse, France.
    Bonin, Pierre
    RISE Research Institutes of Sweden, Materials and Production, Corrosion. Université de Toulouse, France.
    Thierry, Dominique
    RISE Research Institutes of Sweden, Materials and Production, Corrosion. Université de Toulouse, France.
    Le Bozec, Nathalie
    Université de Lyon, France.
    Roggero, Aurelien
    Université de Lyon, France.
    Pébère, Nadine
    Université de Toulouse, France.
    Ageing processes of coil-coated materials: Temperature-controlled electrochemical impedance analysis2023In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 183, article id 107682Article in journal (Refereed)
    Abstract [en]

    In the present work, an industrial polyester coil-coated steel was characterized by electrochemical impedance spectroscopy (EIS) during immersion in a 0.5 M NaCl solution for different temperatures (30, 40, 50 and 60 °C). The objective was to propose a methodology to follow the ageing of the coil-coated system, from the first stage of water uptake until the blistering appearance. Relevant parameters were extracted from the EIS diagrams to analyse ageing processes of the polymer and of the metal/polymer interface. Water uptake was determined from the high-frequency part of the impedance diagrams using a linear rule of mixtures. By increasing the temperature, both the water uptake kinetics and the water content in the coating increased. The effect of water uptake on the physical structure of the coating (plasticization) was discussed through the analysis of a time constant corresponding to the dielectric manifestation of the polymer glass transition. At 40, 50 and 60 °C, appearance of corrosion was detected on the impedance spectra by a decrease, at low frequency, of the impedance modulus and of the phase angle. For 60 °C, the corroded surface area as a function of time, was assessed from the EIS data analysis with adapted equivalent circuits. The corroded surface areas followed similar trend as blister surface areas determined from images analysis.

  • 44.
    Chai, Guocai
    et al.
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Sandvik Mat Technol, Sandviken, Sweden.
    Kangas, Pasi
    Sandvik Mat Technol, Sandviken, Sweden.
    Super and hyper duplex stainless steels: structures, properties and applications2016In: 21ST EUROPEAN CONFERENCE ON FRACTURE, (ECF21), ELSEVIER SCIENCE BV , 2016, Vol. 2, p. 1755-1762Conference paper (Refereed)
    Abstract [en]

    In oil-gas industry, the exploration and development are now targeted to the deep reservoirs with high pressures, high temperatures and extreme corrosive environments. This requires that the materials used should have a good combination of extra high strength and excellent corrosion resistance. In order to meet these challenges, hyper duplex stainless steels have recently been developed. These materials have nitrogen contents up to about 0.5% and PRE-values close to 50, and show both highest corrosion pitting resistance and highest strength among the existing duplex stainless steels. The purpose of this paper is to provide an overview on hyper duplex stainless steels. It will mainly focus on the material development, microstructures, corrosion properties such as critical pitting corrosion temperature and crevice corrosion resistance, heterogeneous deformation behaviour of duplex stainless steel, and mechanical properties such as tensile properties and fatigue properties. These properties and the ratios of strength/weight will then be compared with those of other type of duplex stainless steels. The potential applications for hyper duplex stainless steels are also discussed. Copyright (C) 2016 The Authors. Published by Elsevier B.V.

  • 45.
    Chang, Tingru
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Atmospheric corrosion of copper and copper-based alloys in architecture: from native surface oxides to fully developed patinas2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Copper and copper-based alloys are commonly used in both ancient and modern architecture. This requires an in-depth fundamental and applied understanding on their atmospheric corrosion behavior at different climatic, environmental and pollutant levels and how these parameters influence e.g. corrosion initiation, patina characteristics, aesthetic appearances, corrosion rates, and runoff rates. This doctoral thesis elucidates the role of native surface oxides on the corrosion performance, corrosion initiation, formation and evolution of corrosion products from hours to months, years and even centuries, to diffuse dispersion of metals from Cu metal/Cu alloy surfaces focusing on the roles of alloying elements, microstructure, and deposition of chlorides. In-depth investigations have been performed at both laboratory and field conditions on commercial Cu metal and copper-based alloys of a golden alloy (Cu5Zn5Al1Sn) and Sn-bronzes (Cu4Sn, Cu6Sn). Patina characteristics and relations to the presence of microstructural inclusions have in addition been investigated for historic patinas of Cu metal roofing of different age and origin, highlighted with data for a 400 years old Cu patina exposed at urban conditions.

    A multi-analytical approach comprising microscopic, spectroscopic and electrochemical methods was employed for in-depth investigations of surface characteristics and bulk properties. Electron backscattered diffraction (EBSD) was utilized to characterize the microstructure. Auger electron spectroscopy (scanning-AES), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES) were employed for surface chemical compositional analysis, and atomic absorption spectroscopy (AAS) to assess the amount of metal release from the patinas. Cathodic reduction (CR) and electrochemical impedance spectroscopy (EIS) were used to assess the amount and corrosion resistance of corrosion products formed at laboratory conditions. Confocal Raman micro-spectroscopy (CRM), infrared reflection absorption spectroscopy (IRAS) and grazing incidence X-ray diffraction (GIXRD) were used to identify the phases of corrosion products. Colorimetry was used to assess surface appearances.

    Cu5Zn5Al1Sn and Cu4Sn/Cu6Sn exhibit favorable bulk properties with respect to corrosion in terms of smaller grain size compared with Cu metal and show non-significant surface compositional variations. The presence of multi-component native oxides predominantly composed of Cu2O enriched with Sn-oxides on Cu4Sn/Cu6Sn, and with ZnO, SnO2 and Al2O3 on Cu5Zn5Al1Sn, improves the barrier properties of the native surface oxides and the overall corrosion resistance of Cu4Sn/Cu6Sn and Cu5Zn5Al1Sn. The formation of Zn/Al/Sn-containing corrosion products (e.g. Zn5(CO3)2(OH)6 and Zn6Al2(OH)16CO3·4H2O) significantly reduces the corrosion rate of Cu5Zn5Al1Sn in chloride-rich environments. Alloying with Sn reduces the corrosion rate of Sn-bronze at urban environments of low chloride levels but results in enhanced corrosion rates at chloride-rich marine conditions.

    A clear dual-layer structure patina was observed for centuries-old naturally patinated copper metal with an origin from the roof of Queen Anne's Summer Palace in Prague, the Czech Republic. The patina comprises an inner sub-layer of Cu2O and an outer sub-layer of Cu4SO4(OH)6/Cu3SO4(OH)4. Abundant relatively noble inclusions (mainly rosiaite (PbSb2O6)) were observed and incorporated in both the copper matrix and the patina. The largest inclusions of higher nobility than the surrounding material create significant micro-galvanic effects that result in a fragmentized patina and large thickness ratios between the Cu4SO4(OH)6/Cu3SO4(OH)4 and the Cu2O sub-layer, investigated via a statistical analysis of inclusions and patina characteristics of eight different historic urban copper patinas.

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    Thesis-Tingru Chang
  • 46.
    Chang, Tingru
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. KTH, Centres, Center for the Advancement of Integrated Medical and Engineering Sciences, AIMES. Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Herting, Gunilla
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Fan, Yanmiao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Babu, Prasath
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Malkoch, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Blomberg, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Odnevall, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, Centres, Center for the Advancement of Integrated Medical and Engineering Sciences, AIMES. Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Effect of blue light illumination on atmospheric corrosion and bacterial adhesion on copper2024In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 230, article id 111909Article in journal (Refereed)
    Abstract [en]

    The effect of blue light on atmospheric corrosion of Cu and on the antimicrobial properties was explored upon exposure mimicking the condition of hygienic surface disinfection. The results show that blue light illumination enhanced the formation of Cu2O, resulting in a slightly increased corrosion resistance of Cu without pre-deposited NaCl, whereas the enhanced formation of Cu2O, CuCl and/or Cu(OH)3Cl on copper with pre-deposited NaCl caused concomitant corrosion product flaking and a reduced corrosion resistance. The blue light induced enhancement of Cu corrosion led to increased surface roughness and more pronounced integration of bacteria within the corrosion products.

  • 47.
    Chang, Tingru
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Maltseva, Alina
    PSL Univ, Chim ParisTech, CNRS, IRCP, F-75005 Paris, France..
    Volovitch, Polina
    PSL Univ, Chim ParisTech, CNRS, IRCP, F-75005 Paris, France..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    A mechanistic study of stratified patina evolution on Sn-bronze in chloride-rich atmospheres2020In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 166, article id 108477Article in journal (Refereed)
    Abstract [en]

    The complex stratified patina formed on Sn-bronze in chloride-rich atmospheres has been explored through long-term field exposures and short-term laboratory investigations using a multi-analytical approach. The stratified patina is composed of Cu2O- and Cu-2(OH)(3)Cl-rich sublayers intercalated by Sn-oxides, mainly SnO2. The stratification is triggered by events of high chloride deposition, resulting in repeated dissolution and solidification of sublayers, whereby redox reactions between the intermediate products of Sn- and Cu-chlorides play a crucial role. Sn-induced patina stratification is a major reason for enhanced patina flaking on Sn-bronze and its accelerated corrosion rate compared to Cu metal in marine environments.

  • 48.
    Chang, Tingru
    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.
    de la Fuente, D.
    Chico, B.
    Morcillo, M.
    Welter, J. -M
    Leygraf, Christopher
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Analysis of historic copper patinas. Influence of inclusions on patina uniformity2017In: Materials, E-ISSN 1996-1944, Vol. 10, no 3, article id 298Article in journal (Refereed)
    Abstract [en]

    The morphology and elemental composition of cross sections of eight historic copper materials have been explored. The materials were taken from copper roofs installed in different middle and northern European environments from the 16th to the 19th century. All copper substrates contain inclusions of varying size, number and composition, reflecting different copper ores and production methods. The largest inclusions have a size of up to 40 μm, with most inclusions in the size ranging between 2 and 10 μm. The most common element in the inclusions is O, followed by Pb, Sb and As. Minor elements include Ni, Sn and Fe. All historic patinas exhibit quite fragmentized bilayer structures, with a thin inner layer of cuprite (Cu2O) and a thicker outer one consisting mainly of brochantite (Cu4SO4(OH)6). The extent of patina fragmentation seems to depend on the size of the inclusions, rather than on their number and elemental composition. The larger inclusions are electrochemically nobler than the surrounding copper matrix. This creates micro-galvanic effects resulting both in a profound influence on the homogeneity and morphology of historic copper patinas and in a significantly increased ratio of the thicknesses of the brochantite and cuprite layers. The results suggest that copper patinas formed during different centuries exhibit variations in uniformity and corrosion protection ability.

  • 49. Chen, Jiaxin
    et al.
    Obitz, C
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, Faculty of Science & Engineering.
    Forssgren, B
    CORROSION KINETICS OF NICKEL-BASE ALLOYS WITH HIGH CHROMIUM CONTENTS UNDER SIMULATED BWR NORMAL WATER CHEMISTRY CONDITIONS AND HIGH FLOW VELOCITY2015Conference paper (Refereed)
    Abstract [en]

    In light water reactors corrosion-induced material degradation is a critical issue not only for material integrity but also for plant radiation field build-up. In BWRs nickel-base alloys, such as Alloy 600, Alloy 82 and Alloy 182, are applied in various parts of reactor components including welds. However, their corrosion mechanisms are not very well understood. Although the complex compositions of different nickel-base alloys generally prohibit us to single out some specific alloy constituent having a major impact on alloy corrosion rate, a higher chromium content is often thought to be beneficial to forming a more protective oxide film against corrosion attack. In this paper we report a corrosion kinetics study on high chromium nickel-base alloy welding consumables, Alloy 52M and Alloy 152, under simulated BWR normal water chemistry conditions and high flow velocity for up to nine weeks exposure. The corrosion rates are derived from measurements of weight losses of test coupons, oxide thicknesses with infrared ellipsometry, and microstructures of oxide films with electron microscopy. The obtained corrosion rates are then compared to that for Alloy 182, Alloy 82 and Alloy 600. The results show that the corrosion rate for Alloy 52M is similar to those for Alloy 182, whereas the rate for Alloy 152 is reduced to less than half. These observations indicate that the corrosion kinetics for nickel-base alloys is complex and alloy chromium content alone is not a dominant factor in influencing alloy corrosion rate.

  • 50.
    Cheng, Jie
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tsinghua University, Beijing, China.
    Pan, J.
    Wang, T.
    Lu, X.
    Micro-galvanic corrosion of Cu/Ru couple in potassium periodate (KIO4) solution2018In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 137, p. 184-193Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the study of micro-galvanic corrosion of the Cu/Ru couple in KIO4 solution. Practical nobility across the Cu/Ru interface was evaluated by Volta potential mapping, and the morphological changes were monitored by in-situ atomic force microscopy measurements during exposure in a KIO4 solution. Chemical composition of precipitated corrosion product was analyzed by Confocal Raman spectroscopy immediately after the exposure. The results show that Cu is the anode of the Cu/Ru couple, and accelerated dissolution of Cu preferentially occurs near the Cu/Ru interface. However, subsequent formation of insoluble Cu(IO3)2·nH2O leads to precipitation, which impedes further Cu corrosion.

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