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  • 251.
    Melander, Arne
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. KTH Royal Institute of Technology, Sweden.
    Thoors, Håkan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Stenberg, Niclas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. KTH Royal Institute of Technology, Sweden.
    Ning, Ma
    RWTH Aachen University, Germany.
    Spring back evaluation for high and ultra high strength sheet steels with the bending under tension machine2015Inngår i: International Journal of Material Forming, ISSN 1960-6206, E-ISSN 1960-6214, Vol. 8, nr 1, s. 137-144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Bending Under Tension (BUT) machine is used for evaluation of spring back in sheet metal forming. A strip is drawn over a rotating cylindrical die with different restraining forces. The strip is allowed to spring back after drawing and the curvature of the strip is measured. The loading sequence is typical to wall sections of pressed components, side wall curl, where the material has been bent, unbent and finally unloaded. The test was performed on four high and ultra high strength steels with tensile strengths in the range from 800 MPa to 1300 MPa. A clear separation of the data for the four steels was demonstrated. It was analysed to what extent the differences in spring back between the different steels was related to the differences in tensile strengths. A finite element simulation model was used to simulate the strip curvature after BUT testing. The material parameters of the model were fitted to monotonic uniaxial and equibiaxial tests and uniaxial cyclic tests. The model could describe the experimental data in a satisfactory way.

  • 252.
    Mellin, Pelle
    et al.
    RISE., Swerea. KTH Royal Institute of Technology, Sweden.
    Jönsson, Christina
    RISE - Research Institutes of Sweden, Material och produktion, IVF, Energi och miljö. KTH Royal Institute of Technology, Sweden.
    Åkermo, Malin
    KTH Royal Institute of Technology, Sweden.
    Fernberg, Patrik
    RISE., Swerea. Luleå University of Technology, Sweden.
    Nordenberg, Eva
    Siemens Industrial Turbomachinery AB, Sweden.
    Brodin, Håkan
    Siemens Industrial Turbomachinery AB, Sweden.
    Strondl, Annika
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. KTH Royal Institute of Technology, Sweden.
    Nano-sized by-products from metal 3D printing, composite manufacturing and fabric production2016Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 139, s. 1224-1233Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recently, the health and environmental perspective of nano-materials has gained attention. Most previous work focused on Engineered Nanoparticles (ENP). This paper examines some recently introduced production routes in terms of generated nano-sized by-products. A discussion on the hazards of emitting such particles and fibers is included. Fine by-products were found in recycled metal powder after 3D printing by Selective Laser Melting (SLM). The process somehow generated small round metal particles (∌1–2 ÎŒm) that are possibly carcinogenic and respirable, but not small enough to enter by skin-absorption. With preventive measures like closed handling and masks, any health related effects can be prevented. The composite manufacturing in particular generated ceramic and carbonaceous particles that are very small and respirable but do not appear to be intrinsically toxic. The smallest features in agglomerates were about 30 nm. Small particles and fibers that were not attached in agglomerates were found in a wide range of sizes, from 1 ÎŒm and upwards. Preventive measures like closed handling and masks are strongly recommended. In contrast, the more traditional production route of fabric production is investigated. Here, brushing residue and recycled wool from fabric production contained few nano-sized by-products.

  • 253.
    Mellin, Pelle
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Lyckfeldt, Ola
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Harlin, P.
    AB Sandvik Materials Technology, Sweden.
    Brodin, H.
    Siemens Industrial Turbomachinery AB, Sweden.
    Blom, H.
    Carpenter Powder Products AB, Sweden.
    Strondl, Annika
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Evaluating flowability of additive manufacturing powders, using the Gustavsson flow meter2017Inngår i: Metal Powder Report, ISSN 0026-0657, E-ISSN 1873-4065Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Gustavsson flow meter (including standard ISO-13517) is in this paper used to measure flow rate of fine AM powders. In the current paper, the results are compared to the Hall flow meter and a Freeman FT4 powder rheometer in terms of success of measuring these AM powders. The range of possible powders to measure is smaller with Gustavsson flow meter; but in this range, the difference in flow time is greater compared to the Hall flow meter. Compared to using the rheometer, the Gustavsson flow meter is faster and simpler to use; however, other powder-aspects are evaluated since little correlation was found. For the powders in this paper, all methods of characterizing the flowability could distinguish between (1) two alloys, and (2) if the alloys were new or used (in SLM), and (3) if they were dried or non-dried.

  • 254.
    Mellin, Pelle
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Shvab, Ruslan
    Chalmers University of Technology, Sweden.
    Strondl, Annika
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Randelius, Mats
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Brodin, Håkan
    Siemens, Sweden.
    Hryha, Eduard
    Chalmers University of Technology, Sweden.
    Nyborg, Lars
    Chalmers University of Technology, Sweden.
    COPGLOW and XPS investigation of recycled metal powder for selective laser melting2017Inngår i: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to compare, in terms of depth composition profile, a recycled hastelloy X powder and a virgin powder of the same alloy. We compare also the COPGLOW (compacted powder glow discharge analysis) method to the more established XPS (X-ray photoelectron spectroscopy) technique, in terms of similarity in reported elemental contents. A good match between the two methods was obtained on the surface of the powder particles (using an etching depth of 1 nm). Similar oxide layer thickness, of about 0.5–1 nm, was found on both powders by COPGLOW. Oxidation sensitive elements, such as Cr, were found on the surfaces by both XPS and COPGLOW on both powders. Surface content of Si appears to have decreased during use in selective laser melting. Finally, the two methods did not otherwise reveal any unexpected features in the depth profiles.

  • 255.
    Mellin, Pelle
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. KTH Royal Institute of Technology, Sweden.
    Yu, Xi
    Aston University, UK.
    Yang, Weihong
    KTH Royal Institute of Technology, Sweden.
    Blasiak, Wlodzimierz
    KTH Royal Institute of Technology, Sweden.
    Influence of reaction atmosphere (H2O, N2, H2, CO2, CO) on fluidized-bed fast pyrolysis of biomass using detailed tar vapor chemistry in computational fluid dynamics2015Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 54, nr 33, s. 8344-8355Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Secondary pyrolysis in fluidized bed fast pyrolysis of biomass is the focus of this work. A novel computational fluid dynamics (CFD) model coupled with a comprehensive chemistry scheme (134 species and 4169 reactions, in CHEMKIN format) has been developed to investigate this complex phenomenon. Previous results from a transient three-dimensional model of primary pyrolysis were used for the source terms of primary products in this model. A parametric study of reaction atmospheres (H2O, N2, H2, CO2, CO) has been performed. For the N2 and H2O atmosphere, results of the model compared favorably to experimentally obtained yields after the temperature was adjusted to a value higher than that used in experiments. One notable deviation versus experiments is pyrolytic water yield and yield of higher hydrocarbons. The model suggests a not overly strong impact of the reaction atmosphere. However, both chemical and physical effects were observed. Most notably, effects could be seen on the yield of various compounds, temperature profile throughout the reactor system, residence time, radical concentration, and turbulent intensity. At the investigated temperature (873 K), turbulent intensity appeared to have the strongest influence on liquid yield. With the aid of acceleration techniques, most importantly dimension reduction, chemistry agglomeration, and in-situ tabulation, a converged solution could be obtained within a reasonable time (∼30 h). As such, a new potentially useful method has been suggested for numerical analysis of fast pyrolysis.

  • 256.
    Mendibide, Christophe
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Deffo-Ayagou, Martien
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Duret-Thual, Claude
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Kittel, J
    IFP Energies Nouvelles Rond Point de l'échangeur de Solaize, France.
    O2 contamination in SSC / HIC test environments. Impact on test results and discussion on acceptable limits for high H2S content2019Inngår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 12894Corrosion Conference and Expo 2019; Nashville; United States;, National Assoc. of Corrosion Engineers International , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    It is a well admitted fact that oxygen contamination shall be avoided during H2S cracking tests of low alloy steels. In the 2016 revisions of NACE TM0177 and NACE TM0284 documents, quantitative limits of O2 contamination were included with thresholds at 10 and 50 ppb of dissolved oxygen depending on the considered mechanical properties of the tested grade. However, the scientific basis of these values are not well established and there is still a lack of experimental data to illustrate the potential impacts of an oxygen pollution. In addition, while the revised test methods explicitly address initial contamination of the test solution before H2S introduction, they do not consider a continuous oxygen supply during testing. Yet, continuous contamination is extremely difficult to be completely eliminated. In order to better understand the impact of O2 contamination on H2S cracking, a 3-years Joint Industrial Project was launched at the end of 2015. The objectives were to evaluate if O2 contamination can affect H2S cracking test results. A range of steel grades covering different types of O&G applications for High H2S content were used. SSC (uniaxial tensile tests as well as 4 point-bend) and HIC tests were conducted, with well controlled and continuous O2 contamination. Three levels of O2 partial pressures in the gas feed corresponding to 300 ppb, 50 ppb and less than 10 ppb dissolved O2 were used. In parallel to the standard qualification tests, hydrogen permeation and weight-loss corrosion experiments were performed with the same test matrix, covering all regions of the SSC severity diagram. This paper aims at sharing the main results of this project for high H2S content. 

  • 257.
    Mendibide, Christophe
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Duret-Thual, Claude
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Determination of the critical pitting temperature of corrosion resistant alloys in H2S containing environments2018Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 142, s. 56-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The study aimed at developing a test method allowing to evaluate the critical pitting temperature of corrosion resistant alloys in H2S containing environments. ASTM G150 method is indeed not appropriate in sour environment due to the oxidation of H2S at high applied potential and to the decrease of H2S partial pressure as the temperature increases. The study underlines that critical pitting temperature measurement is possible in H2S-containing environments but that the determined temperature is probably not potential independent. The methodology can however be used to rank different alloys provided the selection of a test media representative from service conditions.

  • 258.
    Meroufel, A.
    et al.
    Saline Water Conversion Corporation, Saudi Arabia.
    Larche, Nicolas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Al Fozan, S.
    Saline Water Conversion Corporation, Saudi Arabia.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Crevice corrosion behavior of stainless steels and nickel-based alloy in the natural seawater – Effect of crevice geometry, temperature and seawater world location2017Inngår i: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 69, s. 202-209Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Crevice corrosion is one of the main corrosion problems for metallic alloys used in reverse osmosis (RO) desalination plants. This type of corrosion depends on many factors, that is, alloy composition and/or metallurgy, seawater location, biofilm, temperature, service conditions and crevice geometry. Corrosivity of gulf seawater was compared with the heated Brest seawater (France) for different stainless steels and nickel-based alloy. Maintaining the same experimental conditions, similarity of crevice corrosion performance in both sites relied on the tested alloys. Both crevice corrosion initiation and propagation were evaluated and compared with previous studies. Duplex S32205 and nickel-based N06625 suffered from crevice corrosion contrary to the superaustenitic S31266. However, corrosion results of superduplex S32750 and superaustenitic S31254 were reported very randomly, confirming the “borderline” behavior of these grades in some seawater applications. The impact of the results on the RO plants materials selection is outlined. 

  • 259.
    Moverare, J.J.
    et al.
    Linköping University.
    Leijon, Gunnar
    RISE, Swerea, Swerea KIMAB AB.
    Brodin, H.
    Linköping University.
    Palmert, F.
    Siemens Industrial Turbomachinery AB.
    Effect of SO2 and water vapour on the low-cycle fatigue properties of nickel-base superalloys at elevated temperature2013Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 564, s. 107-115Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study the effect of SO2+water vapour on strain controlled low cycle fatigue resistance of three different nickel based superalloys has been studied at 450°C and 550°C. A negative effect was found on both the crack initiation and crack propagation process. The effect increases with increasing temperature and is likely to be influenced by both the chemical composition and the grain size of the material. In general the negative effect decreases with decreasing strain range even if this means that the total exposure time increases. This is explained by the importance of the protective oxide scale on the specimen surface, which is more likely to crack when the strain range increases. When the oxide scale cracks, preferably at the grain boundaries, oxidation can proceed into the material, causing preferable crack initiation sites and reduced fatigue resistance. © 2012 Elsevier B.V.

  • 260.
    M'Saoubi, R.
    et al.
    Seco Tools AB.
    Chandrasekaran, Hariharan
    RISE, Swerea, Swerea KIMAB AB.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB AB.
    Experimental study and modelling of tool temperature distribution in orthogonal cutting of AISI 316L and AISI 3115 steels2011Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 56, s. 865-877Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cutting tool temperature distribution was mapped using the IR-CCD technique during machining of carbon steel AISI 3115 and stainless steel AISI 316L under orthogonal cutting conditions using flat-face geometry inserts. The effect of work material treatment on tool temperature was investigated, and the results showed that AISI 3115 in heat-treated state displayed higher tool temperature than the as-rolled state. Stainless steel 316L with high sulphur content (0.027 wt.%) and calcium treatment displayed lower cutting tool temperature than the variant with low sulphur (0.009 wt.%). The experimental results were compared with theoretical tool temperature distributions based on a modified version of Komanduri and Hou's analytical model. In particular, variable frictional heat source and secondary shear were introduced and modelling of the tool stress distribution on rake surface was also considered. © 2011 Springer-Verlag London Limited.

  • 261.
    Myrsell, Johan
    RISE, Swerea, Swerea KIMAB AB.
    Effect of shot blasting on process oxidised stainless steel – morphology, chemistry and pickling performance2014Rapport (Fagfellevurdert)
    Abstract [en]

    The oxide scale created during manufacturing of stainless steel is often removed by a chemical pickling with mixed acid. Various pre-treatments to pickling are also applied to increase the efficiency of the oxide scale removal. Shot blasting is one such pre-treatment, which operates to remove a certain amount of oxide and also to generate cracks and openings for the subsequent pickling. In this work, three materials, AISI 2205, 430 and 304 have been blasted and later exposed to mixed acid. This was conducted to quantify the effect shot blasting has on the subsequent pickling of stainless steel. Three shot products and two blasting parameters were investigated and varied. Shot blasting significantly reduced the oxide scale but was unable to remove the chromium oxide layer closest to the steel surface. No significant difference was observed when comparing the result from the three shot products after blasting. Increasing the particle velocity or the coverage rate further enhanced the pickling but reduced the amount of oxide removed during blasting. These effects are however relative small, so in practise relatively mild conditions seems preferable for economic reasons. Oxide scale containing hematite was difficult to remove by both shot blasting and pickling.

  • 262.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Le Bozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Assessment of steel corrosion and deadhesion of epoxy barrier paint by scanning Kelvin probe2018Inngår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 114, s. 123-134Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Marine paints are complex polymeric systems containing layers of different nature that significantly delay the corrosion failures. In order to obtain a rapid ranking in the corrosion protection provided by the paints, it is important to apply sensitive and non-invasive methods for early detection of under paint corrosion. Scanning Kelvin Probe (SKP) was used to determine the mechanism(s) of corrosion and paint de-adhesion. This technique is sensitive to the metal-polymer interface and gives a quick assessment of cathodic delamination or anodic undermining. Depending on the type of exposure the mode of corrosion de-adhesion was evaluated and compared with SKP data obtained under polarization experiments by impressed current in aqueous electrolyte. After exposure, pull off test and Scanning Electron Microscopy – Energy Dispersive X ray Spectrometry (SEM-EDX technique) were applied to determine the paint adhesion stability around the defect and to analyse the steel-paint interface. 

  • 263.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Le Bozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Scanning Kelvin Probe assessment of steel corrosion protection by marine paints containing Zn-rich primer2018Inngår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 125, s. 61-72Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zinc rich primers provide corrosion protection of steel constructions under heavy corrosive conditions such as offshore environments. In general, the paint contains different polymeric layers including the zinc-rich primer with a total thickness larger than 00 μm that significantly delays the degradation of the paint and the observation of corrosion failures. For prediction of corrosion failure and a quick ranking of paint systems, a new sensitive and non-invasive method for assessment has to be developed. Two commercial coatings with different corrosion protection ability were selected for the study. Scanning Kelvin Probe (SKP) was used to determine the sacrificial protection of steel by multilayer paint systems containing zinc rich primer during exposure to accelerated corrosion tests under atmospheric or under immersed conditions. Scanning Electron Microscopy - Energy Dispersive X-Ray Spectrometer (SEM-EDX) techniques were applied to analyse the cross sections after exposure. It is shown that SKP could quickly access the level of cathodic protection of the steel substrate underneath of industrial thick marine paints.

  • 264.
    Nazarov, Andrej P.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Prosek, Tomas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Le Bozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Protective action of vanadate at defected areas of organic coatings on zinc2005Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 152, nr 7, s. B220-B227Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The kinetics of vanadate release from an organic coating and the stability and protective ability of the newly formed vanadate-based films on zinc surfaces have been studied with respect to self-healing ability of vanadate-pigmented organic coatings. The results were compared with those obtained with chromate. The kinetics of vanadate release from a polyester coating was comparable to that of chromate. The methods of X-ray absorption near edge spectroscopy (XANES) and scanning Kelvin probe were used for studying the mechanism of inhibition and the kinetics of vanadate reduction on bare zinc. XANES proved to be a powerful tool for determination of the oxidation state of vanadium in surface films. The experiments showed that vanadate was reduced more rapidly than chromate under the same atmospheric conditions. However, addition of magnesium phosphate resulted in a significantly lower reduction rate of vanadate. The results are discussed in light of the increased adsorption ability of the more negatively charged vanadium(V) species at higher pH, while the oxygen reduction process on zinc is inhibited due to the presence of phosphate. Thus, vanadate in combination with another inhibitor could provide corrosion protection at defects of organic coatings on zinc comparable to that of chromate.

  • 265.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Prosek, Tomas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominque
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Application of EIS and SKP methods for the study of the zinc/polymer interface2008Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, nr 25, s. 7531-7538Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical impedance spectroscopy (EIS) and Scanning Kelvin probe (SKP) were applied to study the zinc/polymer interface. The coating capacitance and the drop of potential across the zinc/epoxy interface are investigated as a function of water penetration and hydrolysis of adhesion bonds. Water penetrates to the interface, decreasing thus the potential drop and increasing the capacitance. Further removal of water leads to the restoration of bonds accompanied by a decrease in capacitance and the return to the initial potential distribution across the interface. Commercial high-performance coil coatings applied to galvanized steel were studied in order to correlate the interface stability and the tendency to blistering. EIS and SKP measurements allowed the evaluation of the electrochemical conditions at the interface. Local adhesion failures caused non-uniformity in the potential profile measured by SKP. Monitoring of changes in impedance at low frequency related to the interface during temperature cycling may be useful for the evaluation of the tendency to blistering.

  • 266.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Application of Scanning Kelvin Probe in the Study of Protective Paints2019Inngår i: Frontiers in Materials, ISSN 2296-8016, Vol. 6, artikkel-id 192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Industrial coatings are composed of layers of different polymers (top coats, primers) containing pigments, corrosion inhibitors, and fillers as well as additives. For corrosion protection, it is vitally important to preserve the strong adhesion and long-term stability of the metal-polymer interface in corrosive environments. In recent decades, the performance of painted materials increased, which requires the application of advanced methods for quick assessing, ranking and predicting corrosion stability. Scanning Kelvin probe (SKP) is a highly sensitive and non-invasive technique to analyze in situ the metal-polymer interface of high-performance industrial coatings. SKP is able to monitor the adhesion and corrosion underneath different kinds of paints without the need for long-term corrosion tests. SKP is a localized electrochemical technique with a spatial resolution in the range of 70–100 μm. Hence, it is possible to obtain information about the intact and corroding portions of the interface at defect sites, corrosion blisters, contaminants, and intermetallics, quality of pretreatments, and the development of galvanic couples that lead to corrosion de-adhesion of the polymeric coatings. This article reviews the application of SKP to the determination of the mechanisms of corrosion de-adhesion of model paints, thick marine paints, coatings with zinc rich primers, automotive paints, and coil coatings applied on galvanized steel substrates. © Copyright © 2019 Nazarov and Thierry.

  • 267.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Prosek, Tomas
    University of Chemistry and Technology Prague, Czech Republic.
    Formation of galvanic cells and localized corrosion of zinc and zinc alloys under atmospheric conditions2017Inngår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 73, nr 1, s. 77-86Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Atmospheric corrosion of Zn and Zn alloys with local NaCl contaminations was studied in situ by scanning Kelvin probe. The corrosion process was accompanied by the formation of clearly separated anodic and cathodic locations and local galvanic cells on the surface. The corrosion activity correlated to variations in Volta potential during air to nitrogen transients. The effect of dielectric and semiconducting solids on the efficiency of cathodic reaction on zinc was investigated. The rate of oxygen reduction was high on semiconducting ZnO films with defective structure, as they are effective donors of electrons. Mg, Ti, Cr, and Al were alloyed to zinc to modify the composition of surface oxide films. The addition of Mg provided the most effective corrosion inhibition, blocking completely the spreading of the cathodic area from NaCl contamination. The other elements had minor influence, but might be applied for further improvement of the Zn-Mg system. The effect of Mg is believed to be connected to semiconducting properties of the formed surface oxide film.

  • 268.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Volovitch, Polina
    Ecole Nationale Supérieure de Chimie de Paris, France.
    Ogle, Kevin
    Ecole Nationale Supérieure de Chimie de Paris, France.
    An SKP and EIS investigation of amine adsorption on zinc oxide surfaces2011Inngår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 43, nr 10, s. 1286-1298Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A metal/oxide/polymer 'interphase' with mixed organic-inorganic nature insures the high stability and the strength of the adhesive joints in a variety of corrosive environments. To model the interaction of epoxy resin with a metal surface, the interaction of amines of different structure with oxidized zinc surfaces was studied by Scanning Kelvin Probe (SKP), FTIR microscopy in atmospheric conditions, and a.c. and d.c. electrochemical techniques in the aqueous electrolyte. It was shown that bidentate ligand-ethylendiamine, forming stable chelate complexes reacts with zinc oxide with redeposition of the interphase. In air and water electrolyte, this ligand shifts the potential of Zn/ZnO electrode to the level of the oxide-free zinc. The amines with low chelating property show low effect on the potential of Zn/ZnO. The SKP was used to measure the potential drop at epoxy resin/zinc interface. On this basis, SKP is proposed as a sensitive nondestructive technique to characterize in situ the interaction of the resin with the metal and the subsequent formation of the interphase in the metal-polymer joints.

  • 269.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vivier, V.
    Sorbonne Universités, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vucko, Flavien
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Tribollet, B.
    Sorbonne Universités, France.
    Effect of mechanical stress on the properties of steel surfaces: Scanning Kelvin probe and local electrochemical impedance study2017Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, nr 2, s. C66-C74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of mechanical stress on the electrochemical properties of ferritic steel SAE 1008 and austenitic stainless steel 301LN was studied using Scanning Kelvin Probe and Localized Electrochemical Impedance Spectroscopy (LEIS) techniques. The probe-working electrode Volta potential difference was mapped in situ under load. It was found that the influence of elastic deformation on the potential was small. Plastic deformation decreased the potential of steel by 150–300 mV, whereas the relaxation of the load from the plastic domain increased the Volta potential. However, some locations, which can contain residual stress, remained at low potential. The pre-strained surfaces were characterized by X-ray Photo Electronic Spectroscopy and by Atomic Force Microscopy. Distribution of the capacitance across strained and strain-free surfaces was studied by LEIS in boric/borate electrolyte. The plastic stress increases the capacitance and decreases the ability of the steels to passivate the surface indicating that emerging of pile-ups of dislocations create defective oxide films. © The Author(s) 2017.

  • 270.
    Nazarov, Andrej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vucko, Flavien
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Hydrogen entry and distribution in steel: Assessments by different local electrochemical techniques2018Inngår i: High-Strength Steels: New Trends in Production and Applications, Nova Science Publishers, Inc. , 2018, s. 35-59Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    The sensitivity of high strength steels (HSS) to hydrogen embrittlement is well established. Cracking is likely to occur even at very low hydrogen content. Hence, it is important to develop new and very sensitive methods (e.g., with high lateral resolution) to study the sources of hydrogen, the distribution of hydrogen in the metal and the mechanisms of hydrogen interaction with microstructural defects and with the surface oxide. This report reviews the application of the localized electrochemical techniques such as Scanning Kelvin Probe (SKP), Scanning Vibration Electrode Technique (SVET), Local Electrochemical Impedance Spectroscopy (LEIS), and Scanning Electrochemical Microscopies (SECM) to study the hydrogenation of austenitic stainless steel, HSS and galvanized HSS under different experimental conditions. For example, SKP can detect 0.01 ppm of atomic hydrogen. This low detection limit is based on the nanoscale interaction of emerged hydrogen with the surface oxide film. Hydrogen diffuses and decreases the Volta potential of the surface at the locations of the emerging due to the reduction of Fe3+ species in the oxide film. It enables real time monitoring of the reduction of oxide film that is related to the failure of the steel passivity. SKP measurements are carried out in air and provide information on the relative hydrogenation due to atmospheric corrosion. In the case of LEIS, hydrogen interacts with surface oxide increasing the capacitance and decreasing the resistance of the film that can be monitored in a water electrolyte. SECM is able to map hydrogen distribution in the electrolyte in the vicinity of the steel surface. Advantages and disadvantages of the different techniques are discussed. The combined effect of mechanical stress and the hydrogen on the steel passivity is also under the scope of this review.

  • 271.
    Necib, S.
    et al.
    Andra, France.
    Bumbieler, F.
    Andra, France.
    Duret-Thual, Claude
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Bulidon, Nicolas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Crusset, D.
    Andra, France.
    Combrade, P.
    ACXCOR, France.
    Assessment of the resistance to environmentally assisted cracking (EAC) of C-steel casing and overpack in the COx claystone2017Inngår i: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 52, s. 95-100Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The French national radioactive waste management agency (Andra) is in charge of studying the disposal of high level wastes (HLW) in deep geological repositories. The reference concept for HLW disposal cells consisted of a multi-barrier system: horizontal boreholes drilled in the Callovo Oxfordian (COx) claystone, cased with carbon steel (C-steel) and containing C-steel overpacks with the nuclear waste packages. Mechanical strength is required for the metallic structures to ensure safety. This study presents the work performed on C-steel to assess in situ mechanical loading, long-term mechanical behaviour based on modelling and environmentally assisted cracking (EAC) susceptibility. The results from in situ experiments have demonstrated anisotropy of the mechanical loading of the casing. Long-term calculations revealed local plastic strain after a few years to a few decades, which highlighted the need to assess the potential risk of EAC. Eventually, the results on EAC assessment in the COx claystone confirmed that the microstructure of the casing and overpack plays a key role on the mechanical resistance. This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems. © 2017 The Author(s). 

  • 272.
    Nice, P.
    et al.
    Statoil ASA, Norway.
    Larche, Nicolas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Amaya, H.
    Nippon Steel and Sumitomo Metal Corporation, Japan.
    Matsuda, Y.
    Nippon Steel and Sumitomo Metal Corporation, Japan.
    Scoppio, L.
    Pipe Team Srl, Italy.
    Fiocchi, M.
    S and L Consulting, Switzerland.
    Evaluation of the corrosion risk of duplex stainless steel UNS S82551 in treated seawater injection service2017Inngår i: NACE - Int. Corros. Conf. Ser., National Assoc. of Corrosion Engineers International , 2017, s. 1225-1239Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In seawater handling systems, the available well tubing materials are Glass Reinforced Epoxy lined low alloy steel or Corrosion Resistant Alloy's (CRA) such as super duplex stainless steel. However, in treated seawater the corrosion risk can be controlled so that lower grade alloys can be considered. Recent efforts have focused attention on better dissolved oxygen controls which permits the investigation and possible use of more cost effective materials such as the duplex stainless steel UNS S82551. Full scale corrosion testing of tubes joined together with a proprietary premium threaded connection was performed in controlled seawater loops simulating service conditions at 30° C. The flow rate and dissolved oxygen were controlled at 5 m/s and <20ppb, respectively. Weekly dissolved oxygen excursions corresponding to 24h at 100ppb followed by 1 hour at 300ppb were included during the 5 months exposure. Corrosion results of UNS S82551 tubing were compared to UNS S31803 and UNS S39274. In parallel, laboratory exposures of coupons were performed in dissolved oxygen controlled cells with and without CREVCORR crevice formers, allowing the measurement of electrochemical potentials as function of dissolved oxygen content (e. g. biofilm ennoblement monitoring) and the related corrosion resistance. The results showed that dissolved oxygen content should be properly controlled below critical values to avoid crevice corrosion of the lesser alloyed duplex stainless steels. In the full scale loop test, UNS S82551 tubes did not exhibit crevice corrosion at threaded connection interfaces under the defined test conditions. 

  • 273.
    Nilsson, Peter
    et al.
    Chalmers University of Technology, Sweden.
    Hedegård, Joakim
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Al-Emrani, Mohammad
    Chalmers University of Technology, Sweden.
    Atashipour, Seyed
    Chalmers University of Technology, Sweden.
    The impact of production-dependent geometric properties on fatigue-relevant stresses in laser-welded corrugated core steel sandwich panels2019Inngår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For bridge deck applications, laser-welded corrugated core steel sandwich panels with dual weld lines per crest and trough have been shown to be highly material- and economically efficient. The nature of welding induces a variation in the geometric properties of the joint that connects the core to the faces. The geometric properties of the joint are the weld width, weld misalignment, and plate gap between the core and the faces. This paper aims to investigate the impact of the variation of the production-dependent geometric properties of the joint on the fatigue-relevant stresses. A secondary aim of this paper is to investigate the impact of contact between the core and the faces on the weld region stresses. Within this paper, the production of four sandwich panels is documented and the manufacturing-dependent geometric properties of their joints are quantified. In order to investigate the impact of the natural variation of the parameters, a parametric study based on finite element analyses is executed. The result of the parametric study shows, among several other findings, that misalignment of the weld line in relation to the core direction can lead to considerable increases in stresses, determinant for the fatigue life of the panel. © 2019, The Author(s).

  • 274.
    Noharet, B.
    et al.
    RISE., Swedish ICT, Acreo.
    Irebo, Tania
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Karlsson, H.
    Cobolt AB, Sweden.
    Compact industrial LIBS systems can assist aluminum recycling2014Inngår i: Laser Focus World, ISSN 10438092, Vol. 50, nr 10, s. 50-52Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    [No abstract available]

  • 275.
    Noharet, Bertrand
    et al.
    RISE., Swedish ICT, Acreo.
    Sterner, Carola
    RISE., Swedish ICT, Acreo.
    Irebo, Tania
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Gurell, Jonas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Bengtson, Arne
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vainik, Rein
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Karlsson, Håkan
    Cobolt AB, Sweden.
    Illy, Euzabeth
    Cobolt AB, Sweden.
    A compact LIBS system for industrial applications2015Inngår i: Proceedings of SPIE: Photonic Instrumentation Engineering II / [ed] Yakov G. Soskind, Craig Olson, SPIE , 2015, Vol. 9369, artikkel-id 936904Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In recent years, laser-induced breakdown spectroscopy (LIBS) has been established as a promising analytical tool for online chemical analysis. The emitted light spectrum is analyzed for instantaneous determination of the elemental composition of the sample, enabling on-line classification of materials. Two major strengths of the technique are the possibilities to perform both fast and remote chemical analysis to determine the elemental composition of the samples under test. In order to reduce the size of LIBS systems, the use of a compact Q-switched diode-pumped solid-state laser (DPSSL) in a LIBS system is evaluated for the industrial sorting of aluminium alloys. The DPSSL, which delivers 150μJ pulses of high beam quality at more than 7KHz repetition rate, provides irradiance on the target that is appropriate for LIBS measurements. The experimental results indicate that alloy classification and quantitative analysis are possible on scrap aluminium samples placed 50 cm apart from the focusing and collecting lenses, without sample preparation. Similar calibration curves and limits of detection are obtained for traditional high-energy low-frequency flashlamp-pumped and low-energy high-frequency diode-pumped lasers, showing the applicability of compact diode-pumped lasers for industrial LIBS applications.

  • 276.
    Nordänger, Svante
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Tidbeck, Björn
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Accelerated corrosion testing - A qualification method for field testing?2017Inngår i: Corrosion Management, ISSN 1355-5243, nr 135, s. 13-16Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accelerated corrosion test methods have been used for a long time to predict performance of coating systems in real applications. These methods have also been used for qualifying individual systems, and for benchmarking different systems in particular applications.

  • 277.
    Norling, Rikard
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Viklund, Peter
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Fireside corrosion during oxyfuel combustion considering various SO 2 contents2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work encompasses the evaluation of deposit and material related limitations on boiler performance and the lifetime of CO2-free, oxyfuel operated power plants. The aim of the study was to determine the reliability of advanced and conventional boiler materials. Six alloys, varying from state-of-the-art ferritic-martensitic and austenitic Fe-based steels to an advanced Ni-based superalloy, were selected for the corrosion tests. The impact on corrosion of oxy-firing of two fuels is considered in the study: S-lean bituminous coal from Indonesia and S-rich bituminous coal from Venezuela. Fireside corrosion tests were performed by two laboratories using varying methodologies: exposures in a combustion test rig using cooled corrosion probes followed by laboratory exposures and isothermal laboratory exposures only. The tests result in a similar ranking of the alloys' corrosion resistance, but also revealed some differences in the corrosion products formed. © 2013 Published by Elsevier Ltd.

  • 278.
    Norling, Rikard
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Viklund, Peter
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Fireside corrosion during oxyfuel combustion considering various SO2 contents2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work encompasses evaluation of deposit and material related limitations on boiler performance and lifetime of CO2-free, oxyfuel operated power plants. The aim of the study was to determine the reliability of advanced and conventional boiler materials. Six alloys, varying from state-of-the-art ferritic-martensitic and austenitic Fe-based steels to an advanced Ni-based superalloy, were selected for the corrosion tests. Impact of oxy-firing of two fuels is considered in the study: S-lean bituminous coal from Indonesia and S-rich bituminous coal from Venezuela. Fireside corrosion tests were performed by two laboratories using varying methodologies: exposures in a combustion test rig using cooled corrosion probes followed by laboratory exposures and isothermal laboratory exposures only. The tests result in a similar ranking of the alloys' corrosion resistance, but also revealed some differences in the formed corrosion products. © 2013 Published Elsevier Ltd.

  • 279.
    Nowak, Andrzej P.
    et al.
    KTH Royal Institute of Technology, Sweden ; Gdansk university of technology, Poland.
    Hagberg, Johan
    KTH Royal Institute of Technology, Sweden.
    Leijonmarck, Simon
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB. KTH Royal Institute of Technology, Sweden.
    Schweinebarth, Hannah
    RISE - Research Institutes of Sweden, Bioekonomi, Bioraffinaderi och energi.
    Baker, Darren A
    RISE - Research Institutes of Sweden, Bioekonomi, Bioraffinaderi och energi.
    Uhlin, Anders
    RISE - Research Institutes of Sweden, Bioekonomi, Bioraffinaderi och energi.
    Tomani, Per
    RISE - Research Institutes of Sweden, Bioekonomi, Bioraffinaderi och energi.
    Lindbergh, Göran
    KTH Royal Institute of Technology, Sweden.
    Lignin-based carbon fibers for renewable and multifunctional lithium-ion battery electrodes2018Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, nr 2, s. 81-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignin-based carbon fibers (LCFs) from the renewable resource softwood kraft lignin were synthesized via oxidative thermostabilization of pure melt-spun lignin and carbonization at different temperatures from 1000°C to 1700°C. The resulting LCFs were characterized by tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD) and confocal Raman spectroscopy. The microstructure is mainly amorphous carbon with some nanocrystalline domains. The strength and stiffness are inversely proportional to the carbonization temperature, while the LCFs carbonized at 1000°C exhibit a strength of 628 MPa and a stiffness of 37 GPa. Furthermore, the application potential of LCFs was evaluated as negative electrodes in a lithium-ion battery (LIB) by electrochemical cycling at different current rates in a half-cell setup. The capacity drops with the carbonization temperature and the LCFs carbonized at 1000°C have a capacity of 335 mAh g-1. All LCFs showed good cycling stability. Because of the mechanical integrity and conductivity of the LCFs, there is no need to apply current collectors, conductive additives or binders. The advantage is an increased gravimetric energy density compared to graphite, which is the most common negative electrode material. LCFs show a promising multifunctional behavior, including good mechanical integrity, conductivity and an ability to intercalate lithium for LIBs.

  • 280.
    Olli, Tobias
    RISE, Swerea, Swerea KIMAB AB.
    Corrosion of stainless steels in contaminated sulfamic acid2012Inngår i: 2012 TAPPI PEERS Conference: Building a Sustainable Future, 2012, s. 185-191Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A comparative study of several industrial relevant stainless steels exposed in 10 wt. % sulfamic acid, NH2HSO3, with 15 ppm chlorides is presented in this paper. Non-welded coupons of austenitic grades EN 1.4307 (S30403), 1.4404 (S31603), lean duplex grades 1.4162 (S32101), 1.4062 (S32202), 1.4362 (S32304) and duplex grades 1.4662 (S82441) and 1.4462 (S32205) were tested. Experiments were performed in double-wall reactor beakers with 10 wt. % NH2HSO3, with 15 ppm chlorides at 80°C. Tests were performed both in stagnant and non-stagnant conditions, circulation held with a magnetic stirrer at 600 rpm. Coupons were immersed for a total time of 168 h, with periods divided into 24 hours, 72 hours and activated prior to the last 72 hours exposure in order to evaluate the ability for material repassivation. Weight loss and thereby corrosion rates were established for all the stainless steel grades. The materials were evaluated on localized corrosion effects after exposure with light optical microscope (LOM). All grades were observed to be corrosion resistant in uninhibited 10 wt. % NH2HSO3 with 15 ppm chlorides at 80°C, i.e. showed a corrosion rate below 0.1 mm/y.

  • 281.
    Olli, Tobias
    RISE, Swerea, Swerea KIMAB AB.
    Oxyfuel annealing of EN 1.4307 austenitic stainless steel tube - Oxide formation and pickling behaviour2011Inngår i: 7th European Stainless Steel Conference: Science and Market, Proceedings, Associazione Italiana di Metallurgia , 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Pilot plant annealing and pickling experiments have been performed to study the effect of the higher water vapour level in oxyfuel annealing on oxidation and pickling. The material studied was extruded tube of an austenitic stainless steel grade EN 1.4307 (AISI 304L) annealed in a propane-fired furnace with air-fuel and flameless oxyfuel burners. The experiments were performed in the time regime of 120 - 360 seconds at a holding temperature of 1100 °C, in order to simulate industrial annealing of tube. Differences in oxidation and pickling behaviour were observed due to increased water concentration in the furnace atmosphere from 14 to 52 mol%. Breakaway oxidation and nodule formation were evident with increased water concentration. Possible causes for the noticeable breakaway oxidation are long holding times, depletion in chromium and thereby formation of an Fe-rich outer oxide scale. Inward and outward growing oxides caused a small increase of the pickling time of EN 1.4307 tubes when pickled a in mixed acid of HNO3 and HF. The flameless oxyfuel burners showed a very high heat transfer due to increased contents of CO2 and H2O in the furnace atmosphere. Thereby, the heating time for the tube material can be decreased with up to 30%.

  • 282.
    Pahverk, Helen
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Sjögren, Lena
    Bimetallkorrosion i atmosfär- Resultat från ett års fältexponering: Bimetallic corrosion under atmospheric conditions - results from one year field exposure2014Rapport (Fagfellevurdert)
    Abstract [sv]

    In the suggested revision of the ISO-standard for the determination of bimetallic corrosion in atmospheric exposure corrosion tests, ISO/CD 7441, three types of specimens for measuring bimetallic corrosion are described: rectangular plates, washers and wire-on-bolt. A similar study, using wire-on-bolt specimens, was performed in the 1970’s*). Since it is not possible to manufacture durable wires of all materials of interest, specimens of the washer type were used in this investigation. Additionally, to obtain a comparison between the specimen types, some material combinations were tested using all three types. The field exposures have been performed at three sites: Stockholm Vanadis (low corrosivity urban atmosphere), Bohus Malmön – Kvarnvik (marine atmosphere) and in Borås (road environment with deicing salts). The exposures started in October – December 2011 with inspection in June - August 2012 and withdrawal in October - December 2012. Results obtained in this investigation are basically consistent with results from the exposures in the 70’s. One difference is that corrosion rates are now lower at the urban site, Stockholm Vanadis. Despite this, aluminium showed larger effects from contact with tin this time, the same being true for aluminium in contact with stainless steel or with zinc coated material. Additionally, there were differences between different aluminium alloys. A schematic overview over results obtained is presented. Specimens types described in ISO/CD 7441 differ in sensitivity. Wire-on-bolt type specimens, with the whole anode area close to the cathode, are the most sensitive while rectangular type specimens show the lowest sensitivity due to the large anode size. A disadvantage with wire-on-bolt type specimens is that all materials cannot be obtained as wires and that corroded wires may break. A clear advantage with washer type specimens is that there is no need to know in advance, which material will be the anode and which the cathode. For measuring corrosion rates by mass loss determination, corrosion products are chemically removed. This was found to be a problem since existing procedures are elaborated for metals with their own corrosion products, not always removing corrosion products from the other metal; chemicals removing the extraneous corrosion products may further attack the metal to be investigated.

  • 283.
    Persson, D.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Karlsson, Oskar
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Corrosion and corrosion products of hot dipped galvanized steel during long term atmospheric exposure at different sites world-wide2017Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 126, s. 152-165Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The atmospheric corrosion of hot dipped galvanized steel was studied in a wide-world exposure in Europe, East Asia and USA. The corrosion product composition, morphology and surface distribution was investigated after 0.5, 1 and 2 years exposure. The corrosion was localized for all exposure conditions with sulfate and chloride containing corrosion products(Zn(OH)2)3·ZnSO4·nH2O,NaZn4(SO4)(OH)6Cl·6H2O and Zn5(OH)8Cl2·H2O formed at the anodic sites in corrosion pits and Zn5(OH)6(CO3)2 mainly in the outer parts of the corrosion products and cathodic areas outside the pits. The content of the sulfate containing corrosion products increased in the order marine&lt;marine/urban, marine/industrial&lt;industrial/urban.

  • 284.
    Persson, Dan
    RISE, Swerea, Swerea KIMAB AB.
    Initial atmospheric corrosion of zinc induced by acetic acid: A quantified in situ IRAS study2008Inngår i: 17th International Corrosion Congress 2008: Corrosion Control in the Service of Society, 2008, Vol. 3, s. 1569-1574Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As part of a broader research program dealing with initial atmospheric corrosion of metals induced by organic acids, infrared reflection absorption spectroscopy (IRAS) has been used to study the initial interaction of acetic acid with zinc in 90% relative humidity and 120 ppb acid concentration under in situ condition. Efforts were made to quantify the identified reaction product species, mainly zinc oxide and zinc acetate. The experimentally obtained results were quantified through calculations using a linear relationship between IRAS peak intensity and layer thickness, and assuming optical constants of zinc acetate dihydrate (Zn(CH 3COO) 2•2H 2O). In all, the in situ studies performed by IRAS provide information on the identity and quantity of reaction products formed. © 2009 by NACE International.

  • 285.
    Persson, Dan
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Prosek, Thomas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    LeBozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Luckeneder, Gerald H.
    Voestalpine, Austria.
    Initial SO2-induced atmospheric corrosion of ZnAlMg coated steel studied with in situ Infrared Reflection Absorption Spectroscopy2015Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 90, s. 276-283Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The initial atmospheric corrosion of ZnAl2Mg2 coated steel in humid air with 80ppb SO2 was studied using in situ Infrared Reflection Absorption Spectroscopy, XRD and SEM. Corrosion products formed in SO2- and SO2 and NaCl containing environments on ZnAl2Mg2 (ZM) were dominated by Mg-containing sulphite and sulphates with sulphite formed mainly initially. The sulphite formation is connected with dissolution of the Mg-containing oxide layer present initially. This is followed by a localised corrosion process where Mg rich phase in the binary eutectic microstructure is dissolved anodically while the Zn-rich phase is the site for the cathodic oxygen reduction.

  • 286.
    Persson, Dan
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    LeBozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Corrosion product formation on Zn55Al coated steel upon exposure in a marine atmosphere2011Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 53, nr 2, s. 720-726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of corrosion products on Zn55Al coated steel has been investigated upon field exposures in a marine environment. The corrosion products consisted mainly of zinc aluminium hydroxy carbonate, Zn0.71Al0.29(OH)2(CO3)0.145·xH2O, zinc chloro sulfate (NaZn4(SO4)Cl(OH)6·6H2O), zinc hydroxy chloride, Zn5(OH)8Cl2·H2O and zinc hydroxy carbonate, Zn5(OH)6(CO3)2 were the first three phases were formed initially while zinc hydroxy carbonate Zn5(OH)6(CO3)2 was formed after prolonged exposure in more corrosive conditions. The initial corrosion product formation was due to selective corrosion of the zinc rich interdendritic areas of the coating resulting in a mixture of zinc and zinc aluminium corrosion products. © 2010 Elsevier Ltd.

  • 287.
    Persson, Dan
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    LeBozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Prosek, T.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    In situ infrared reflection spectroscopy studies of the initial atmospheric corrosion of Zn-Al-Mg coated steel2013Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 72, s. 54-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    NaCl induced atmospheric corrosion of ZnAl2Mg2 coated, electrogalvanised (EG) and hot dipped galvanised (HDG) steel was studied using in situ infrared reflection absorption spectroscopy, XRD and SEM. Initial corrosion leads to the formation of Mg/Al and Zn/Al layered double hydroxides (LDHs) on ZnAl2Mg2, due to the anodic dissolution of Zn-MgZn2 phases and cathodic oxygen reduction on Zn-Al-MgZn2, Al-phases and on zinc dendrites. In contrast to EG and HDG, were no ZnO and Zn5(OH)8Cl2{dot operator}H2O detected. This is explained by the buffering effect of Mg and Al which inhibit the ZnO formation, reduce the cathodic reaction and corrosion rate on ZnAl2Mg2.

  • 288.
    Persson, Daniel
    RISE, Swerea, Swerea KIMAB AB.
    Termodynamisk studie av borstål2014Rapport (Fagfellevurdert)
    Abstract [sv]

    Vid framställning av olika material är introduceringen av legeringselement ett betydelsefullt område. Vid framställning av stål kan egenskaperna för stålet optimeras genom att styra de kemiska reaktionerna som sker i samband med att stålet legeras. För legeringar av stål är låga halter av grundämnet bor av intresse. Tillsatser av bor vid ståltillverkningen har visats ge betydande förbättringar av olika materialegenskaper för stål. Ett känt problem är att bor uppvisar hög affinitet till flera andra grundämnen. Detta leder till att bor vid materialtillverkningen bildar ej önskvärda kemiska föreningar med dessa ämnen vilket leder till att borets bidrag till stålets egenskaper förloras i hög utsträckning. Med hjälp av termodynamiska beräkningsmodeller, såsom CALPHAD-metoden, går det att beräkna olika termodynamiska beskrivningar av kemiska föreningar. Dessa kan därefter sammanställas i databaser för framtida beräkningar. Genom att utföra utvärderingar och beräkningar på system av lägre grad, t.ex. binära system, kan i förlängningen mer komplexa beräkningar utföras på multikomponenta system som innehåller flera olika grundämnen. Databasen i detta projekt saknar en uppdaterad beskrivning av tillgänglig termodynamisk informationen för vissa borkarbider. Syftet med detta examensarbete var att utföra en utvärdering av stål mikrolegerat med bor och utföra en uppdatering av en databas med avseende på utvalda kemiska föreningar. Med programvaran Thermo-Calc har en termodynamisk utvärdering skett av Fe-B-C-systemet med avseende på de tidigare ej beskrivna borkarbiderna Fe3(B,C) och Fe23(B,C)6. De framtagna beskrivningarna av föreningarna implementerades i databasen på ekvationsform och beräkningar utfördes för att påvisa pålitligheten i beskrivningarna. Resultaten från beräkningarna visades överensstämma väl med referenser i litteraturen.

  • 289.
    Persson, Daniel
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Mikhailov, Alexander A.
    Russian Academy of Sciences, Russia.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    In situ studies of the corrosion during drying of confined zinc surfaces2007Inngår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 58, nr 6, s. 452-462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The corrosion process during the drying out of zinc surfaces confined in crevices was studied using real time photograpy and in situ FTIR microspectroscopy. A pH-indicator was used to visualise differences in the pH during the drying process. The distribution and the composition of the corrosion products after several wetting and drying cycles were studied with FTIR microspectroscopy and SEMEDS. An area with high pH formed during the drying process at the border of the electrolyte, with a zone of white corrosion products that contained zinc hydroxycarbonate in the electrolyte inside this area. A differential aeration cell is present at the border of the electrolyte, and the cathodic oxygen reduction reaction takes place close to the border of the electrolyte during the drying process. The corrosion attack and the distribution and composition of the corrosion products on the surface depend strongly on the drying process of the surface. The corrosion attack of confined surfaces was localised, with a significantly higher corrosion attack in some areas. Outside the drying front a thin layer of electrolyte formed as a result of surface tension driven flow of electrolyte from the electrolyte border. This effect was attributed to the alkaline pH of the electrolyte due to the oxygen reduction reaction at the border. A galvanic element was formed between the local cathodes in the area outside the drying front and the anode in the area with bulk electrolyte. The main corrosion products detected after several wet dry cycles were ZnO, Zn5(OH)6(CO3)2, and Zn5(OH)8Cl2 · H2O, but Na2CO3 · 10H2O was also detected. The corrosion products were non-homogeneously distributed on the surface and the distribution was related to the anodic and cathodic processes that took place in different regions on the surface during the corrosion process.

  • 290.
    Pettersson, Niklas
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Frisk, Karin
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Fluch, Rainer
    Böhler Edelstahl Gmbh, Austria.
    Experimental and computational study of nitride precipitation in a CrMnN austenitic stainless steel2017Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 684, s. 435-441Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The austenitic CrMnN stainless steels are high-strength, tough, and non-magnetic, and are used in oil field applications. The steels have high alloying contents, and precipitation of Cr-nitrides and/or intermetallic phases can occur when cooling through the temperature region 950–700 °C. The nitride precipitates appear in the grain boundaries but can be difficult to observe in the microstructure due to their small size. However, there is an effect of precipitation on corrosion and impact strength and a modelling approach to predict precipitation is valuable for alloy and process development. In the present work precipitation simulations were applied to a CrMnN steel composition, and coupled to experimental investigations after heat treatments at 700 and 800 °C. The early stages, with short heat-treatment times, were studied. The simulations were performed using TC-PRISMA, a software for calculation of multiphase precipitation kinetics, using multicomponent nucleation and growth models. Dedicated thermodynamic and kinetic databases were used for the simulations. The main precipitate was identified by experiments and simulations to be the Cr2N nitride, and the precipitation during isothermal heat treatments was investigated. Isothermal precipitation diagrams are simulated, and the influence of precipitation kinetics on toughness is discussed.

  • 291.
    Pettersson, Niklas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Pettersson, Rachel F. A.
    Jernkontoret, Sweden.
    Wessman, Sten
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Precipitation of Chromium Nitrides in the Super Duplex Stainless Steel 25072015Inngår i: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 46, nr 3, s. 1062-1072Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Precipitation of chromium nitrides during cooling from temperatures in the range 1373 K to 1523 K (1100 °C to 1250 °C) has been studied for the super duplex stainless steel 2507 (UNS S32750). Characterization with optical, scanning and transmission electron microscopy was combined to quantify the precipitation process. Primarily Cr2N nitrides were found to precipitate with a high density in the interior of ferrite grains. An increased cooling rate and/or an increased austenite spacing clearly promoted nitride formation, resulting in precipitation within a higher fraction of the ferrite grains, and lager nitride particles. Furthermore, formation of the meta-stable CrN was induced by higher cooling rates. The toughness seemed unaffected by nitrides. A slight decrease in pitting resistance was, however, noticed for quenched samples with large amounts of precipitates. The limited adverse effect on pitting resistance is attributed to the small size (~200 nm) of most nitrides. Slower cooling of duplex stainless steels to allow nitrogen partitioning is suggested in order to avoid large nitrides, and thereby produce a size distribution with a smaller detrimental effect on pitting resistance.

  • 292.
    Pettersson, Niklas
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Wessman, Sten
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Hertzman, Staffan
    Outokumpu Stainless Research Foundation, Sweden.
    Studer, Andrew
    Australian Nuclear Science and Technology Organisation, Australia.
    High-Temperature Phase Equilibria of Duplex Stainless Steels Assessed with a Novel In-Situ Neutron Scattering Approach2017Inngår i: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 48, nr 4, s. 1562-1571Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Duplex stainless steels are designed to solidify with ferrite as the parent phase, with subsequent austenite formation occurring in the solid state, implying that, thermodynamically, a fully ferritic range should exist at high temperatures. However, computational thermodynamic tools appear currently to overestimate the austenite stability of these systems, and contradictory data exist in the literature. In the present work, the high-temperature phase equilibria of four commercial duplex stainless steel grades, denoted 2304, 2101, 2507, and 3207, with varying alloying levels were assessed by measurements of the austenite-to-ferrite transformation at temperatures approaching 1673 K (1400 °C) using a novel in-situ neutron scattering approach. All grades became fully ferritic at some point during progressive heating. Higher austenite dissolution temperatures were measured for the higher alloyed grades, and for 3207, the temperature range for a single-phase ferritic structure approached zero. The influence of temperatures in the region of austenite dissolution was further evaluated by microstructural characterization using electron backscattered diffraction of isothermally heat-treated and quenched samples. The new experimental data are compared to thermodynamic calculations, and the precision of databases is discussed.

  • 293.
    Pettersson, Niklas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Wessman, Sten
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thuvander, Mattias
    Chalmers University of Technology, Sweden.
    Hedström, Peter
    KTH Royal Institute of Technology, Sweden.
    Odqvist, Joachim
    KTH Royal Institute of Technology, Sweden.
    Pettersson, Rachel F. A.
    The Swedish Steel Producers' Association, Sweden.
    Hertzman, Staffan
    Outokumpu Stainless Research Foundation, Sweden.
    Nanostructure evolution and mechanical property changes during aging of a super duplex stainless steel at 300°C2015Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 647, s. 241-248Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nanostructure evolution and the corresponding changes in mechanical properties of a super duplex stainless steel 2507 (UNS S32750) during aging at 300. °C up to 12,000. h have been investigated. Microstructural studies using transmission electron microscopy and atom probe tomography show that subtle Cr concentration fluctuations develop during aging. The amplitude of the concentration fluctuations is proportional to the hardness of the ferrite phase, and it is also proportional to the decrease in room temperature impact toughness during aging. The fracture behaviour of the alloy changes gradually from ductile to cleavage fracture, upon aging. The cracks were found to propagate through the ferrite phase, partly along deformation twin interfaces, and delamination between the austenite and ferrite phases was observed.

  • 294.
    Pettersson, Rachel
    RISE, Swerea, Swerea KIMAB AB.
    Effects of composition on the corrosion of Fe-Ni-Cr alloys in chlorinating and sulfidising environments2009Inngår i: Materials at High Temperature, ISSN 0960-3409, E-ISSN 1878-6413, Vol. 26, nr 3, s. 217-222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of six austenitic alloys has been prepared in which the nickel content was successively increased from 14 to 78% while retaining a base level of 20%Cr. These were isothermally exposed for 100 hours at 700°C in an air-45% water vapour environment, an oxidising-sulfidising environment (air + 49%Ar + 26%H2O + 1%SO2) and a chlorinating environment at low oxygen partial pressure (argon + 0.1%O2 + 15-26%H2O + 0.2-0.35%HCl). The latter two environments gave opposite trends in terms of gross mass change. High metal loss associated with breakaway oxidation occurred at a low nickel contents in the chlorinating environment. In the sulfidising environment the most severe effects were observed at high nickel levels and were associated with the formation of sulfur-containing oxide nodules. © 2009 Science Reviews 2000 Ltd.

  • 295.
    Pettersson, Rachel
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Flyg, Jesper
    RISE, Swerea, Swerea KIMAB AB.
    Influence of alloying additions on pitting and crevice corrosion of stainless steels in NaCI and NaBr solutions2008Inngår i: EUROCORR 2008 - European Corrosion Congress: Managing Corrosion for Sustainability, Book of Abstracts, 2008, s. 470-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Varying levels of chromium, nickel and molybdenum have been made to laboratory heats of stainless steels in order to quantify the effect of these alloying elemente on pitting and crevice corrosion. The nickel level was either 2%, resulting in a ferritic microstructure, alternatively 25% or 40% to give an austenitic steel. The molybdenum level was 2% or 4% and the chromium level 20 or 25%. Critical temperatures for pitting corrosion or crevice corrosion have been evaluated in 1M NaCl and 0.2 or 0.05M NaBr. Results are evaluated in using multiple linear regression to obtain modified Pitting Resistance Equivalent equations relating corrosion performance to alloy content. Electrochemical studies have also been used to elucidate the component propagation and repassivation processes.

  • 296.
    Pettersson, Rachel
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Karlsson, F.
    Siemens Industrial Turbomachinery.
    Flyg, Jesper
    RISE, Swerea, Swerea KIMAB AB.
    Hot corrosion of two nickel-base superalloys under alkali sulfate deposition conditions2009Inngår i: Materials at High Temperature, ISSN 0960-3409, E-ISSN 1878-6413, Vol. 26, nr 3, s. 251-257Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The single crystal MD2 (Ni-8Cr-5Al-5Co-2Mo-8W-6Ta-1Ti) and the polycrystalline Inconel 792 (Ni-13Cr-3Al-9Co-2Mo-4W-4Ta-4Ti) were exposed at 850 and 900°C in an severely sulfidising environment comprising synthetic air with 8% water vapour and 2000 ppm SO2, and a deposit of 20mol% Na2SO4 + 80mol% K2SO4 applied every 160 hours. Results were evaluated in terms of mass change, which indicated the existence of an incubation time before the onset of extensive attack, and post-test metallography to evaluate metal loss. Metallographic studies are presented showing the complex external oxide scale formation and internal oxidation and sulfidation. © 2009 Science Reviews 2000 Ltd.

  • 297.
    Pettersson, Rachel
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Nordling, Magnus
    RISE, Swerea, Swerea KIMAB AB.
    Corrosion of overlay weld cladding in waterwalls of waste fired CFB boiler2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Candidate materials for weld overlay coating of waterwalls have been investigated to determine corrosion rates and investigate corrosion mechanisms. Test waterwall panels with single layer weld overlays were exposed for a total of 7727 h in a 75 MW.tot circulating fluidised bed boiler with 470°C/65 bar steam data. The fuel was 60% industrial waste and 40% household waste, resulting in very corrosive conditions. Six weld overlay materials were tested: the well proven alloy 625, a modified alloy 625 in which niobium was replaced by tungsten, alloy 59, alloy 22, a cheaper nickel base alloy 650 which contains some iron and a 310 grade stainless steel. Significant material loss occurred for all the panels. The nickel base alloys mainly developed hemispherical pits while the stainless steel exhibited relatively uniform corrosion. This means that the progress of the corrosion process is easier to monitor by inspection for the stainless steel. Detailed analyses of the corrosion products showed that conditions were sufficiently oxidising to allow formation of metal oxides, but that there were also extensive deposits of alkali and heavy metal chlorides. The corrosion mechanism is discussed in terms of formation of a molten salt layer which dissolves the oxide layer by fluxing. © 2009 Institute of Materials, Minerals and Mining.

  • 298.
    Prestat, M.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Holzer, L.
    Zurich University of Applied Sciences, Germany.
    Lescop, B.
    Université de Bretagne Occidentale, France.
    Rioual, S.
    Université de Bretagne Occidentale, France.
    Zaubitzer, C.
    ETH Zurich, Switzerland.
    Diler, Erwan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Microstructure and spatial distribution of corrosion products anodically grown on zinc in chloride solutions2017Inngår i: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 81, s. 56-60Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zinc substrates were electrochemically oxidized in NaCl solution to produce corrosion patinas. XRD, XPS and Raman analyses enabled the identification of simonkolleite and zinc oxide as the patina constituents. FIB-SEM imaging shows that the upper part of the patinas is a network of simonkolleite nanosheets with an open microstructure that is unlikely to act as a significant barrier for corrosion processes. STEM investigations and Raman mapping measurements reveal the presence of a ca. 20–400 nm thin nanoporous ZnO-rich film below the simonkolleite and covering the zinc substrate. Under potentiostatic conditions, the reduced cathodic activity of the patina-covered zinc electrodes is assigned to this nanoporous ZnO layer. 

  • 299.
    Prestat, Michel
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Soares Costa, Josiane
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB. Université de Bretagne Occidentale, France.
    Lescop, Benoit
    Université de Bretagne Occidentale, France.
    Rioual, Stephane
    Université de Bretagne Occidentale, France.
    Holzer, Lorenz
    Zurich University of Applied Sciences, Switzerland.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Cathodic Corrosion of Zinc under Potentiostatic Conditions in NaCl Solutions2018Inngår i: ChemElectroChem, ISSN 2196-0216, Vol. 5, nr 8, s. 1203-1211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Zinc electrodes were polarized cathodically at moderate overpotentials in NaCl 0.6 M solutions under potentiostatic conditions for 7 to 17 hours at room temperature. Corrosion products were characterized by using optical microscopy, XRD, Raman microscopy, XPS, and FIB-SEM. Close to the open-circuit potential, the corrosion products were formed by simonkolleite and the electrochemical response exhibits anodic features. At more negative potentials, the current density remains cathodic throughout the polarization and the deposits on the electrode surface consist almost solely of ZnO. The soluble zinc species necessary for ZnO deposition originate from localized dissolution of the substrate in the form of pits. This effect is assigned to the strong alkalinization of the surface due to oxygen reduction. Despite developing greater surface area than bare zinc substrates, the nanostructured ZnO deposits reduced the cathodic activity.

  • 300.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Dubois, Francois
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Kouril, Milan
    Institute of Chemical Technology, Czech Republic.
    Scheffel, Bert
    Fraunhofer, Germany.
    Degres, Yves
    NKE, France.
    Jouannic, M.
    NKE, France.
    Taube, Michelle
    National Museum of Denmark, Denmark.
    Dubus, Michel
    Centre de Recherche et de Restauration des Musées de France, France.
    Hubert, Vera
    Swiss National Museum, Switzerland.
    Thierry, Doinique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Application of automated corrosion sensors for real-time monitoring in atmospheres polluted with organic acids2011Inngår i: 18th International Corrosion Congress 2011, 2011, s. 1477-1484Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Loggers for continuous measurement of the corrosion rate of metals under atmospheric conditions were developed. The electronic unit measures and records changes in the electrical resistance of a thin metal track applied on an insulating substrate. If the metal corrodes, the effective cross-sectional area of the track decreases and the electrical resistance increases. Part of the metal track is protected by an organic coating and, thus, serves as a reference to compensate for resistivity changes due to varying temperature. Sensors made of silver, copper, iron / steel, zinc, bronze and lead with sensitivities tailored to different environments are available. Thin film metal sensors with the metal track thickness from 50 to 800 nm were made by physical vapour deposition (PVD). Examples of the logger application for continuous measurements of metal corrosion rates in air are given. Due to the sensitivity of the measurement as high as 0.1 nm, in terms of corrosion depth, changes in air corrosivity were registered within tens of minutes or hours even in low-corrosive environments. At relative humidities from 15 to 80 % and at the temperature of 20 °C, it was used for monitoring in the air polluted with controlled amounts of formic and acetic acids at concentrations from 0-1590 and 0- 870 ppb, respectively. Gases in these concentrations were reported to be found in museums and other cultural heritage institutions and are expected to cause accelerated deterioration of metal objects. Threshold limits of the formic acid concentration in air at 80 % RH and at 20 °C causing changes in the classification of indoor air corrosivity according to ISO 11844-1 are given.

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