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  • 1.
    Adhikari, Arindam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Pani, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Deidinaitei, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Electrochemical behavior and anticorrosion properties of modified polyaniline dispersed in polyvinylacetate coating on carbon steel2008In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, no 12, p. 4239-4247Article in journal (Refereed)
    Abstract [en]

    Conducting polyaniline (Pani) was prepared in the presence of methane sulfonic acid (MeSA) as dopant by chemical oxidative polymerization. The Pani-MeSA polymer was characterized by FT-IR, UV-vis, X-ray diffraction (XRD) and impedance spectroscopy. The polyrner was dispersed in polyvinylacetate and coated oil carbon steel samples by a dipping method. The electrochemical behavior and anticorrosion properties of the coating, oil carbon steel in 3% NaCl were investigated using Open-circuit Potential (OCP) versus time of exposure, and electrochemical techniques including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and cyclic voltammetry (CV). During initial exposure, the OCP dropped about 0.35 V and the interfacial resistance increased several times, indicating I certain reduction of the polymer and oxidation of the steel surface. Later the OCP shifted to the noble direction and remained at a stable value during the exposure up to 60 days. The EIS monitoring also revealed the initial change and later stabilization of the coating. The stable high OCP and low coating impedance Suggest that the conducting polymer maintains its oxidative state and provides corrosion protection for carbon steel through out the investigated period. The polarization curves and CV show that the conducting polymer coating induces a passive-like behavior and greatly reduces the corrosion of carbon steel.

  • 2.
    Anghel, Clara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Limbäck, M.
    Szakalos, P.
    Effects of Pt surface coverage on oxidation of Zr and other materials2008In: Journal of ASTM International, ISSN 1546-962X, Vol. 5, no 2Article in journal (Refereed)
    Abstract [en]

    Certain elements, including noble metals, are identified to influence corrosion behavior of many metals in high-temperature water/steam and O 2. We have previously reported effects of porous Pt coatings on the thermal oxidation of Zr, Fe, Ni, Cr and GaAs in O2. Effects of Pt on oxidation of Zircaloy-2 In H2O have also been observed at temperatures near 400°C. An enhanced oxidation rate Is observed in all of the studied systems upon a sufficiently high surface Pt-particle density. Even more interesting, low Pt-particle density in most cases leads to a decreased oxidation rate. In the case of Zr and Zircaloy-2 the beneficial effect of Pt is stronger when hydrogen is present In the metal substrate and in the oxide layer. From 18O/SIMS experiments it is concluded that, for a sufficiently high Pt-particle density on the surface, enhanced transport of dissociated oxygen, On- (n=0; 2), towards the oxide/metal interface occurs in all of the studied systems. An oxygen spillover from Pt particles to the adjacent surface is a known phenomenon in catalysis and partly explains the results observed also in the current study of oxidation of Zr-based materials. Such a spillover involves a high surface diffusivity of dissociated oxygen, O n-, which results In an increased gradient of On- across the oxide scale. In turn, the high oxygen gradient enhances the transport of oxygen towards the substrate/oxide-interface. This shows that not only diffusivlty but also an effective activity of dissociated oxygen at the external oxide surface influences the oxidation rate. Naturally, the effects of Pt are maximized when small (nm-sized) and evenly distributed Pt particles are present on the surface. In our presentation a summary of obtained results of Pt additions on different materials will be given with suggested interpretations. Especially, the observed beneficial combination of Pt and hydrogen in the oxidation of Zr-based materials Is discussed with a possible mechanistic explanation. Parallels are also drawn to the potential effect of Noble Metal Chemical Application (NMCA), used in a large fraction of the U.S. BWRs, on the corrosion resistance of Zr-based claddings.

  • 3.
    Anghel, Clara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Limbäck, Magnus
    Szakalos, Peter
    Effects of Pt Surface Coverage on Oxidation of Zr and Other Materials2009In: ZIRCONIUM IN THE NUCLEAR INDUSTRY: 15TH INTERNATIONAL SYMPOSIUM, 2009, Vol. 1505, p. 285-302Conference paper (Refereed)
    Abstract [en]

    Certain elements, including noble metals, are identified to influence corrosion behavior of many metals in high-temperature water/steam and O-2. We have previously reported effects of porous Pt coatings on the thermal oxidation of Zr, Fe, Ni, Cr, and GaAs in O-2. Effects of Pt on oxidation of Zircaloy-2 in H2O have also been observed at temperatures near 400 degrees C. An enhanced oxidation rate is observed in all of the studied systems upon a sufficiently high surface Pt-particle density. Even more interesting, low Pt-particle density in most cases leads to a decreased oxidation rate. In the case of Zr and Zircaloy-2 the beneficial effect of Pt is stronger when hydrogen is present in the metal substrate and in the oxide layer. From O-18/SIMS experiments it is concluded that, for a sufficiently high Pt-particle density on the surface, enhanced transport of dissociated oxygen, On- (n=0; 2), towards the oxide/metal interface occurs in all of the studied systems. An oxygen spillover from Pt particles to the adjacent surface is a known phenomenon in catalysis and partly explains the results observed also in the current study of oxidation of Zr-based materials. Such a spillover involves a high surface diffusivity of dissociated oxygen, On-, which results in an increased gradient of On- across the oxide scale. In turn, the high oxygen gradient enhances the transport of oxygen towards the substrate/oxide-interface, This shows that not only diffusivity but also an effective activity of dissociated oxygen at the external oxide surface influences the oxidation rate. Naturally, the effects of Pt are maximized when small (nm-sized) and evenly distributed Pt particles are present on the surface. In our presentation a summary of obtained results of Pt additions on different materials will be given with suggested interpretations. Especially, the observed beneficial combination of Pt and hydrogen in the oxidation of Zr-based materials is discussed with a possible mechanistic explanation. Parallels are also drawn to the potential effect of Noble Metal Chemical Application (NMCA), used in a large traction of the U.S. BWRs, on the corrosion resistance of Zr-based claddings.

  • 4. Bahar, B.
    et al.
    Herting, G.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Hakkila, K.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Virta, M.
    The interaction between concrete pavement and corrosion-induced copper runoff from buildings2008In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 140, no 1-3, p. 175-189Article in journal (Refereed)
    Abstract [en]

    Changes in chemical speciation of copper and the capacity of concrete pavement to retain copper in runoff water from external buildings have been investigated at urban field conditions, and in parallel laboratory experiments simulating outdoor scenarios. The research study showed the concrete surface to form a copper rich surface layer (approximate to 50 mu m thick) upon exposure, and a high capacity to significantly reduce the bioavailable fraction of released copper (20-95%). The retention capacity of copper varied between 5 and 20% during single runoff events in the laboratory, and between 10 and 40% of the total copper release during single natural runoff events. The capacity to retain and reduce the bioavailable fraction of non-retained copper increased with increasing wetness of the concrete surfaces, increasing pH of the runoff water and decreasing flow rates. Bioassay testing with bacterial and yeast bioreporters showed the bioavailable fraction of non-retained copper to be significantly lower than the total copper concentration in the runoff water, between 22 and 40% for bacteria and between 8 and 31% for yeast. The application of generated data to simulate a fictive outdoor scenario, suggests a significant reduction of bioavailable and total copper to background values during environmental entry as a result of dilution, and the interaction with solid surfaces, organic matter and complexing agents already in the drainage system.

  • 5.
    Bahar, Babak
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Corrosion-induced copper release from rain gutters2008In: Metall (Berlin. 1947), ISSN 0026-0746, Vol. 62, no 3, p. 129-135Article in journal (Refereed)
    Abstract [en]

    While runoff rates from copper roofs have been extensively studied during the last years, corresponding studies from copper rain gutters have been missing. A laboratory investigation has been undertaken to examine the influence of important runoff water parameters on the copper runoff from rain gutters. At a given rainfall quantity, the release rate of copper increases with decreasing runoff water intensity and decreasing degree of gutter inclination, and with increasing runoff acidity and increasing Cu2+-ion concentration in the runoff water. A comparison of the predicted long-term copper release from the gutter-system compared to the roof on a real building suggests that less than 5% of the total copper runoff originates from the gutter. However, single rain events may result in higher release rates, especially during the initial rain portion.

  • 6.
    Belonoshko, Anatoly B.
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Rosengren, Anders
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Thermal regimes of passivative oxide film formation on Al surface: Theoretical and experimental study2006In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 600, no 20, p. 4796-4800Article in journal (Refereed)
    Abstract [en]

    We report results of ab initio molecular dynamics simulations of an Al surface exposed to an oxygen atmosphere. The results, supported by experiments performed in this study, demonstrate that the Al surface, by reacting with the oxygen molecules, can be heated above melting temperature and transformed into a liquid. This process is potentially capable of creating an amorphous corrosion scale which might possess an enhanced resistance to deterioration.

  • 7.
    Bertling, Sofia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Berggren Kleja, Daniel
    Department of Soil Sciences, Swedish University of Agricultural Sciences, SLU, Uppsala, Sweden.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Long-term corrosion-induced copper runoff from natural and artificial patina and its environmental impact2006In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 25, no 3, p. 891-898Article in journal (Refereed)
    Abstract [en]

    The overall objective of this paper is to present an extensive set of data for corrosion-induced copper dispersion and its environmental interaction with solid surfaces in the near vicinity of buildings. Copper dispersion is discussed in terms of total copper flows, copper speciation and bioavailability at the immediate release situation, and its changes during transport from source to recipient. Presented results are based on extensive field exposures (eight years) at an urban site, laboratory investigations of the runoff process, published field data, generated predictive site-specific runoff rate models, and reactivity investigations toward various natural and manmade surfaces, such as those in soil, limestone, and concrete. Emphasis is placed on the interaction of copper-containing runoff water with different soil systems through long-term laboratory column investigations. The fate of copper is discussed in terms of copper retention, copper chemical speciation, breakthrough capacities, and future mobilization based on changes in copper concentrations in the percolate water, computer modeling using the Windermere Humic Aqueous Model, and sequential extractions. The results illustrate that, for scenarios where copper comes in extensive contact with solid surfaces, such as soil and limestone, a large fraction of released copper is retained already in the immediate vicinity of the building. In all, both the total copper concentration in runoff water and its bioavailable part undergo a significant and rapid reduction.

  • 8.
    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.

  • 9.
    Chen, Zhuo Yuan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    The role of particles on initial atmospheric corrosion of copper and zinc: lateral distribution, secondary spreading and CO2-/SO2-influence2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The role of sodium chloride (NaCl) particles and ammonium sulfate ((NH4)2SO4) particles on the initial atmospheric corrosion of copper and zinc was investigated under in situ and ex situ conditions using microgravimetry, FTIR spectroscopy, ion chromatography, scanning electron microscopy with x-ray microanalysis and the scanning Kelvin probe. For the first time, in situ infrared spectra were collected on a micron level during particle induced atmospheric corrosion using a recently developed experimental set-up for in situ FTIR microspectroscopy. Lateral distribution of corrosion and reaction products on copper and zinc surfaces was determined and could be connected with the mechanisms of the initial particle induced corrosion. The recently discovered secondary spreading effect from NaCl electrolyte droplets on metal surfaces was studied under in situ conditions and the effect of CO2 on the spreading process was elaborated. The ambient level of CO2 (350 ppm, 1 ppm = 10-6 volume parts) results in a relatively low secondary spreading effect, whereas the lower level of CO2 (<5 ppm) causes a much faster secondary spreading effect over a large area. At low CO2 concentration alkaline conditions will prevail in the cathodic area, leading to large changes in the surface tension at the oxide/electrolyte interface in the peripherical parts of the droplet. This induces a surface tension driven convective flow of electrolyte from the NaCl droplet. The continuous growth of the secondary spreading area at low CO2 concentration is possible due to the galvanic coupling with the droplet leading to transport of sodium ions to this region and maintenance of the alkaline conditions. At 350 ppm CO2, carbonate formation in the secondary spreading area results in lowering of the pH, increasing the surface tension of the oxide/electrolyte interface and inhibiting the secondary spreading. CO2 strongly affects the NaCl-induced atmospheric corrosion rate of copper. The overall influence of CO2 and NaCl depends on at least three identified mechanisms. At low NaCl particle density, CO2 affects the secondary spreading effect from the electrolyte droplet. This leads to a larger effective cathodic area at low CO2 concentration and a higher corrosion rate. The more alkaline surface electrolyte present at low CO2 concentration also affects the formation of corrosion products and the amount of soluble copper chloride. Whereas the presence of larger amounts of soluble chloride tends to increase the corrosion rate, the formation of CuO results in a more protective surface film which decreases the corrosion rate. This effect was observed at higher NaCl particle densities, where the secondary spreading areas overlapped with adjacent NaCl particle clusters. The formation of CuO leads to lower corrosion rates compared to ambient CO2 concentration in which this phase was not formed. For zinc, the formation of a more protective corrosion product layer was not observed and the corrosion rate is generally higher for low than for ambient CO2 concentration. The presence of NaCl particles on the metal surfaces strongly affects the SO2 interaction with the metal surfaces. The oxidation of S(IV) turned out to be fast at the area of the NaCl-containing electrolyte droplet, both for copper and zinc. On copper surfaces, both sulphate (SO4 2-) and dithionate (S2O6 2-) ions formed which is consistent with a copper catalysed reaction route for sulfite oxidation including the formation of a Cu(II)–sulfito complex as an important step. For zinc, a surface mediated sulfite oxidation process leads to rapid formation of sulphate in the electrolyte droplet area. The presence of SO2 strongly inhibits the secondary spreading due to the decrease in pH induced by absorption of SO2 in the cathodic areas. The presence of gaseous oxidants, such as NO2 and O3, has previously been considered as an important prerequisite for the oxidation of sulfite on copper. The results obtained here suggest that the formation of local electrochemical cells induced by deposited NaCl particles could be another important route for S(IV)- oxidation to sulfate formation. On copper, SO2 was also found to promote the formation of less soluble copper chlorides, such as paratacamite (Cu2(OH)3Cl) and nantokite (CuCl). The electrolyte droplet was dried after 24 hours of exposure due to the formation of less soluble paratacamite (Cu2(OH)3Cl) and nantokite (CuCl) and led to a decrease in the corrosion rate. Thus, SO2 alone promotes the corrosion rate of copper, whereas in the presence of NaCl particles the corrosion rate of copper may slow down due to the formation of insoluble copper chloride compounds. The lateral distribution of corrosion products after exposure of NaCl contaminated copper and zinc surfaces to humid air with gaseous pollutants is a result of the formation of local electrochemical cells at the particles and concomitant differences in chemical composition and pH. For (NH4)2SO4 deposited copper and zinc surfaces the corrosion effects increase with the amount of pre-deposited particles and with the exposure time. On copper, the size of the particles affects the corrosion rate, smaller particles resulting in a higher corrosion rate than larger particles at equal amount of deposition. The formation of Cu2O was the dominant corrosion product after exposure longer than 10 days. (NH4)2SO4 particles result in enhanced Cu2O formation on copper due to a reaction sequence involving catalysis by NH3. The corrosion of copper by (NH4)2SO4 particles was much larger than that induced by NaCl particles. However, for zinc, the (NH4)2SO4 particles lead to smaller corrosion effects than those of NaCl particles. For both particles, significant corrosion attack was observed at relative humidity (RH) lower than the deliquescence point of the salts.

  • 10.
    Chen, Zhuo Yuan
    et al.
    Swedish Corrosion Institute.
    Persson, D.
    Swedish Corrosion Institute.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    In situ studies of the effect of SO2 on the initial NaCl-induced atmospheric corrosion of copper2005In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 152, no 12, p. B526-B533Article in journal (Refereed)
    Abstract [en]

    The initial SO2-induced atmospheric corrosion of copper deposited with NaCl has been examined with Fourier transform infrared microspectroscopy under in situ and ex situ conditions in order to reveal the spatial distribution of reaction products. The oxidation of S(IV) turns out to be fast at the area of the NaCl-containing electrolyte droplet, and both sulfate (SO42-) and dithionate (S2O62-) ions form. A copper-catalyzed reaction route for the sulfite oxidation has been suggested, which includes the formation of a Cu(II)-sulfito complex as an important step. The presence of gaseous oxidants such as NO2 and O-3 has previously been considered as an important prerequisite for the oxidation of sulfite on copper. The results obtained here suggest that the formation of local electrochemical cells induced by deposited NaCl particles could be another important route for S(IV) oxidation to sulfate formation. SO2 was found to promote the formation of less soluble paratacamite [Cu-2(OH)(3)Cl] and nantokite (CuCl), which may slow down the atmospheric corrosion rate of copper.

  • 11.
    Chen, Zhuo Yuan
    et al.
    Swedish Corrosion Institute.
    Persson, D.
    Swedish Corrosion Institute.
    Nazarov, A.
    Swedish Corrosion Institute.
    Zakipour, S.
    Swedish Corrosion Institute.
    Thierry, D.
    Swedish Corrosion Institute.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    In situ studies of the effect of CO2 on the initial NaCl-induced atmospheric corrosion of copper2005In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 152, no 9, p. B342-B351Article in journal (Refereed)
    Abstract [en]

    The effect of carbon dioxide (CO2) on the NaCl-induced atmospheric corrosion of copper was studied using in situ Fourier transform infrared microspectroscopy, in situ scanning Kelvin probe, and scanning electron microscopy/energy-dispersive analysis by X-ray. The copper surface was contaminated with a single NaCl particle and then exposed to 80 +/- 2% relative humidity clean humidified air with two concentrations of CO2 (< 5 and 350 ppm). After formation of an electrolyte droplet secondary spreading of electrolyte from the peripherical parts of the droplet was observed. The secondary spreading effect, which was much larger at < 5 ppm CO2 than at 350 ppm, was a consequence of the formation of a galvanic element between a local cathode outside the edge of the droplet and an anode in the droplet. This lead to alkaline conditions in the secondary spreading area and transport of Na+ ions to the local cathode. The large secondary spreading at low CO2 concentration was possible due to lowering of the surface tension of the electrolyte/metal oxide interface at the peripheral parts of the droplet. Carbonate formation lowered the pH when the CO2 concentration was 350 ppm and resulted in a decrease of the pH and inhibition of the secondary spreading.

  • 12.
    Chen, Zhuo Yuan
    et al.
    Swedish Corrosion Institute.
    Persson, D.
    Swedish Corrosion Institute.
    Samie, F.
    Swedish Corrosion Institute.
    Zakipour, S.
    Swedish Corrosion Institute.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Effect of carbon dioxide on sodium chloride-induced atmospheric corrosion of copper2005In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 152, no 12, p. B502-B511Article in journal (Refereed)
    Abstract [en]

    The effect of carbon dioxide (CO2) on sodium chloride (NaCl) induced atmospheric corrosion of copper was studied in laboratory exposures using microgravimetry, ion chromatography, Fourier transform infrared spectroscopy, and scanning electron microscopy with X-ray microanalysis. With lower amount of NaCl particles on the copper surface (< 15 mu g/cm(2)), the corrosion rate was higher with < 1 ppm CO2 than with 350 ppm CO2, and for higher amount of NaCl (> 15 mu g/cm(2)), the corrosion was higher with 350 ppm CO2. With lower amount of NaCl and low CO2 concentration, a secondary spreading of electrolyte occurred from the droplets that formed at the particle clusters. This led to a larger effective cathodic area and a higher corrosion rate. However, at higher surface concentration of NaCl a spatial interaction effect between the local corrosion sites counteracted the increase in the corrosion rate due to overlap of the cathodic areas from the particles. Another factor, which influenced the corrosion process, was the effect of CO2 on the pH of the surface electrolyte. Higher pH (< 1 ppm CO2 concentration) increased the formation of CuO, which improved the corrosion resistance of the corrosion product layer but hindered the formation of insoluble CuCl, whereby more soluble chloride ions were available for triggering localized corrosion and accelerating the initial atmospheric corrosion of copper. Hence, the overall influence of CO2 and NaCl depends on at least three identified mechanisms.

  • 13. Chen, Zhuo Yuan
    et al.
    Persson, Dan
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Initial NaCl- Particle Induced Atmospheric Corrosion of Zinc-Effect of CO2 and SO22008In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 50, no 1, p. 111-123Article in journal (Refereed)
    Abstract [en]

    Initial corrosion and secondary spreading effects during NaCl particle induced corrosion on zinc was explored using in situ and ex situ FTIR microspectroscopy, optical microscopy, and SEM/EDAX. The secondary spreading effect which occurs upon introduction of humid air on NaCl deposited zinc surfaces was strongly dependent on the CO2 and SO2 content of the introduced air. Ambient level of CO2 (350 ppm) resulted in a relatively low spreading effect, whereas the lower level of CO2 (<5 ppm) caused a much faster spreading over a larger area. In the presence of SO2, the secondary spreading effect was absent which could limit the cathodic process in this case. At <5 ppm CO2, the corrosion is more localized, with the formation of simonkolleite (Zn5(OH)8Cl2 · H2O), zincite (ZnO) and sodium carbonate (Na2CO3), and a larger effective cathodic area. At 350 ppm CO2, the corrosion is more general and formation of simonkolleite, hydrozincite (Zn5(OH)6(CO3)2) and sodium carbonate was observed. Sodium carbonate was mainly formed in more alkaline areas, in the inner edge of the electrolyte droplet and in the secondary spreading area. Oxidation of sulphur and concomitant sulphate formation was enhanced in the presence of NaCl particles, due to the formation of a droplet, the separation of the anodic and cathodic areas and the accompanying differences in chemical composition and pH in the surface electrolyte.

  • 14.
    Chen, Zhuo Yuan
    et al.
    Swedish Corrosion Institute.
    Tidblad, J.
    Swedish Corrosion Institute.
    Persson, D.
    Swedish Corrosion Institute.
    Zakipour, S.
    Swedish Corrosion Institute.
    Kucera, V.
    Swedish Corrosion Institute.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    The Effect of Ammonium Sulfate Particles on the Atmospheric Corrosion of CopperManuscript (preprint) (Other academic)
  • 15.
    Chen, Zhuo Yuan
    et al.
    wedish Corrosion Institute, Sweden.
    Zakipur, S.
    Persson, D.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    The Combined Effects of Gaseous pollutants and Sodium Chloride Particles on the Atmospheric Corrosion of Pure Copper2005In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 61, no 11, p. 1022-1034Article in journal (Refereed)
    Abstract [en]

    The atmospheric corrosion of pure copper has been investigated after the deposition of sodium chloride (NaCI) particles and exposure to humid air containing gaseous pollutants. Microgravimetry, Fourier transform infrared (FTIR) micro-spectroscopy, and scanning electron microscopy with x-ray microanalysis were used for the investigation of corrosion processes and products. The effect of NaCl particles on the mass gain was much higher than that of gaseous pollutants. With deposition of NaCl particles on the copper surfaces, the corrosion rate increased significantly, with severe corrosion attack mainly localized to the NaCl particle clusters. A similar corrosion rate was found, however, after exposure to pure humid air and to humid air containing gaseous pollutants, sulfur dioxide (SO2), ozone (O-3), nitrogen dioxide (NO2), and SO2 + NO2. The corrosion rate was not dependent on the concentration of the pollutants. However, this was not the case for the combination of SO2 and O-3, leading to a significantly higher corrosion rate at higher concentrations. Exposure of copper samples with NaCl particles deposited resulted in unevenly distributed corrosion product clusters, with a distribution of corrosion products that could be associated with the locations of the particle clusters. Around the particle clusters, the corrosion resulted in areas with different amounts of corrosion products. After 10 days of exposure to humid air containing 100 ppb SO2 and 100 ppb NO2 + SO2, cuprite (Cu2O), paratacamite (Cu-2[OH](3)Cl), carbonate (CO32-), and sulfate (SO42-) were observed mainly in the area of the original particle cluster, with some sutfate and copper hydroxysulfate also in the areas outside. After 10 days of exposure to humid air containing 100 ppb O-3 + SO2, cuprite (Cu2O), hydroxychloride (maybe paratacamite, Cu-2[OH](3)Cl), carbonate (CO32-), and sutfate (SO42-) were observed in the area of the original particle cluster. A circular zone containing brochantite (Cu-4[OH](6)SO4) was formed around and outside of the original particle cluster, and the formation of this phase was promoted by the presence of NaCl particles on the surface. The location of anodic and cathodic reactions during the corrosion process leads to the distribution of different corrosion products on the surface.

  • 16. Cui, D.
    et al.
    Rondinella, V. V.
    Low, J.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Tamborini, G.
    Spahiu, K.
    On the behaviour of spent fuel under simulated early canister-failure conditions2006In: Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM, 2006, p. 925-932Conference paper (Refereed)
    Abstract [en]

    This paper reports on the results of a long term experiment on spent fuel leaching, canister corrosion and radionuclide immobilization under repository conditions corresponding to early canister failure. A γ-dose of 850 mGy per hour, and Ar-flushed synthetic groundwater were used. During the first 287 days, the fractions of inventory in aqueous phase per day (f/d) increased nearly constantly for each radionuclide (except for 100Mo), with higher fractions for fission products than for actinides. After this initial stage, iron, cast iron and copper coupons (of̃30 mm2 size) were inserted into the leaching vessel: the concentrations of 238U, 237Np and 99Tc decreased by 80%, 97% and 88% to relatively stable levels (500ppb, 0.2ppb and 0.6ppb respectively). 239Pu concentrations slightly increased to the level of PuO2 solubility (0.5ppb). The leaching process for Cs, Mo and 90Sr was not influenced by the added metals. The pH and Eh values and corrosion potential were measured. The polarization resistance (Rp) was obtained from fitting of electrochemical impedance spectra, and then corrected by the surface area of the sample. The corrosion current density Icorr was calculated according to the Stern-Gary relationship, and using the same Tafel constants (26 mV)for all samples, i.e., Icorr = 0.026/Rp. The momentary corrosion rates of iron, cast iron and copper (Cu/Cu+) calculated based on the Faraday's law are in reasonable agreement with the values estimated from observation of thickness of corrosion layers using SEM microscope. The copper coupon appeared much more stable against corrosion than the other coupons. The corrosion layer and radionuclides deposited on corrosion products on iron coupons were analyzed by SEM-EDS and SIMS. Si was found to be coordinated with all iron corrosion products; however, redox sensitive elements U and Pu were mainly coordinated with the inner layer of iron corrosion products even though some 1-2 μm sized uranium-silica rich particles were found on the outer side of the iron corrosion layer. The findings of this work contribute to an improved understanding of the behaviour of spent fuel under near field repository conditions.

  • 17.
    Davoodi, Ali
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Mechanistic studies of localized corrosion of Al alloys by high resolution in-situ and ex-situ probing techniques2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    A multi-analytical approach based on in-situ and ex-situ local probing techniques was employed to investigate localized corrosion mechanisms of some aluminum alloys in chloride containing solutions, focusing on the influence of intermetallic particles (IMPs) in the alloys. In the EN AW-3003 alloy, SEM-EDS analysis revealed constituent and dispersoid IMPs. There are two types of constituent IMPs, with size ranging from 0.5 to several μm, and composition typically Al6(Fe,Mn) or Al12(Mn,Fe)3Si, respectively,having a Mn/Fe ratio of about 1:1. Fine dispersoids of 0.5 μm or less in size normally have the composition Al12Mn3Si1-2. Scanning Kelvin probe force microscopy (SKPFM measurements showed that the constituent IMPs have a higher Volta potential compared to the matrix, and the Volta potential difference increased with particle size, probably related to the composition of the IMPs. The SKPFM results also showed a Volta potential minimum in the boundary region adjacent to some larger IMPs.

    The open-circuit potential and electrochemical impedance spectroscopy measurements indicated local electrochemical activities occurring on the surface, and active-like dissolution in the acidic solutions, but a passive-like behavior in the near-neutral solutions. Infrared reflection-absorption spectroscopy measurements after exposure and thermodynamic calculations suggested the formation of mixtures of aluminum oxyhydroxide and acetate on the surface in acetic acid solutions. The formation and fraction of dominant species of the corrosion products depend on the pH of the solution, and aluminum chloride compounds may form at very low pH.

    Moreover, an integrated in-situ atomic force microscopy (AFM) and scanningelectrochemical microscopy (SECM) set-up was used to investigate the localized activities on the surface. With a dual mode probe, acting as both AFM tip and SECM microelectrode, concurrent topography and electrochemical current images were obtained on the same area of the surface. Numerical simulations of the SECM suggested a micrometer lateral resolution under favorable conditions and the ability to resolve μmsized active sites with a separation distance of about 3 μm or larger. The simulations were verified by SECM mapping of the aluminum alloys in the chloride solutions. The AFM/SECM measurements revealed enhanced cathodic activity on some larger IMPs and local anodic dissolution around larger IMPs. In-situ AFM monitoring confirmed preferential dissolution in the boundary region adjacent to some of these IMPs. The results elucidate the micro-galvanic effect and size effect of the IMPs during the initiation of localized corrosion of the Al alloys.

    Furthermore, differences in corrosion properties between EN AW-3003 and a newly developed Al–Mn–Si–Zr alloy were studied with a similar approach. Compared to EN AW-3003, the new alloy had a smaller number of particles with a large Volta potential difference relative to the matrix. In slightly corrosive solutions extensive localized dissolution and deposition of corrosion products occurred on EN AW-3003, whereas only a small number of corroding sites and “tunnel-like” pits occurred on the Al–Mn–Si–Zr alloy. The lower corrosion activity and the smaller tunnel-like pits resulted in lower material loss of the Al–Mn–Si–Zr alloy, which is beneficial for applications using a thin material.

  • 18.
    Davoodi, Ali
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Farzadi, Ali
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Zhu, Y.
    Developing an AFM-Based SECM system; Instrumental setup, SECM simulation, characterization, and calibration2008In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 155, no 8, p. C474-C485Article in journal (Refereed)
    Abstract [en]

    An integrated atomic force microscopy/scanning electrochemical microscopy (AFM/SECM) system was developed as an in situ local electrochemical probing technique. It consists of a dual-mode probe acting as an AFM cantilever and SECM microelectrode to simultaneously obtain the topography and electrochemical current map of the same area. Two types of probes with different geometries were used. The scan velocity and concentration profile of the redox mediator during the scan were simulated, using the equations of convection-diffusion mass transport coupled with continuity and momentum in three dimensions under steady-state and transient conditions. The temporal and spatial resolutions of the probes were investigated. It was found that, during a normal scan rate (around 1 Hz), the effect of convective transport is negligible and the SECM lateral resolution depends on the geometrical parameters. With favorable geometry, a probe with a Pt microelectrode of 1 mu m diameter can distinguish two active sites with a distance of at least 3-4 mu m. The paper also reports experiments for characterization and calibration of the AFM/SECM system. Concurrent AFM and SECM images obtained on a gold band calibration sample verify the high-resolution capability of the SECM of one or a few micrometers with optimized conditions.

  • 19. Davoodi, Ali
    et al.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Parvizi, Reza
    Minuscule device for hydrogen generation/electrical energy collection system on aluminum alloy surface2011In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 36, no 4, p. 2855-2859Article in journal (Refereed)
    Abstract [en]

    Cogeneration of hydrogen and electrical energy in a single system is still a challenging issue. In this work, in a micro scale, a novel miniaturized system is introduced to capture the electrical energy of produced hydrogen on aluminum alloy by using an ultra-microelectrode based on scanning electrochemical microscopy (SECM). Sophisticated nanosize atomic force microscopy (AFM) based SECM probe could collect the electrochemical current close proximity distance from the aluminum surface to attain the highest possible current efficiency. Various collected current levels were associated to the aluminum microstructure constituents. It is expected that future development in instrumentation could principally facilitate SECM as a tool for hydrogen economy.

  • 20. Dong, Q.
    et al.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Sproule, G. I.
    Graham, M. J.
    Platinum-catalyzed high temperature oxidation of metals2007In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 49, no 8, p. 3348-3360Article in journal (Refereed)
    Abstract [en]

    Samples of At, Cr, Ni, and Zr were sputter-coated with porous Pt-films with a particle size of 20-30 nm. Thermal oxidation of these samples was studied by gas phase analysis (GPA) and secondary ion mass spectrometry (SIMS). SIMS analysis on partly Pt-coated samples of At, Cr, Ni, and Zr at different oxide depths in areas with Pt and in areas away from Pt indicates an enhanced inward oxide growth in the Pt area and mm-ranged distance from Pt-area. Weight gain measurements on Pt-coated Ni samples show a reduced or increased oxidation rate depending on the amount of porous Pt-coating. Pt has two effects on the thermal oxidation of metals and the overall effect of Pt on the oxidation of metals depends on the mechanism of oxide growth in the absence of Pt.

  • 21.
    Dong, Qian
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    An experimental method to identify various oxygen species transported in oxides2007In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 306, no 1-2, p. 166-172Article in journal (Refereed)
    Abstract [en]

    Oxygen transport in oxides can take place in molecular, atomic and ionic form. An experimental method is described which separates the contributions of molecules, atoms and ions to the overall oxygen transport in oxides. The method comprises gas phase analysis and the use of oxygen isotopes O-16 and O-18. In the general case, exposure to non-equilibrated O-2 containing 60-70% O-18 is optimal to obtain the highest accuracy in the measurement. The method is exemplified by distinguishing non-ionic (molecular and atomic) oxygen transport from ionic oxygen transport in a commercial yttria-stabilized zirconia (YSZ) sample in the temperature range of 600-900 degrees C. There is approximately 35% molecular, 20% atomic transport and 45% ionic oxygen transport in YSZ at 600 degrees C. It is found that the fraction percent of non-ionic oxygen transport decreases with increasing temperature, and ionic oxygen transport increases sharply with increasing temperature.

  • 22.
    Dong, Qian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Hultquist, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Does nitrogen transport in vitreous silica only take place in molecular form?2006In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 10, p. 104904-Article in journal (Refereed)
    Abstract [en]

    It is generally believed that nitrogen transport in vitreous silica exclusively takes place in molecular form, although no evidence for this is found in the literature. Actually, an analysis of literature data of transport of nitrogen and noble gases in vitreous silica at 900 °C suggests it may not be the case. In order to clarify the operative species of nitrogen transport in this material, experiments of permeation and uptake/release have been performed with the use of gas phase analysis and isotopic labeling of nitrogen. By comparing the relative distributions of N2 14,14, N2 14,15, and N2 15,15 in exposure gas, permeated gas and released gas with distribution of equilibrated nitrogen molecules, the percentage of dissociated nitrogen in the transport has been evaluated at different temperatures. It has then been found that nitrogen undergoes dissociation not only on the surface of vitreous silica but also in its bulk and that the overall dissociation of nitrogen increases with temperature. It is concluded that nitrogen diffuses both in molecular and atomic forms with approximately 15% atomic nitrogen transport at 900 °C. The observed transport rates are explained by diffusion of molecular nitrogen combined with a retardation of dissociated nitrogen in reversible traps.

  • 23.
    Dong, Qian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Tang, Qing
    Li, Wenchao
    Al2O3-TiC-ZrO2 nanocomposites fabricated by combustion synthesis followed by hot pressing2008In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 475, no 1-2, p. 68-75Article in journal (Refereed)
    Abstract [en]

    Al2O3-TiC-ZrO2 nanocomposites were prepared by combustion synthesis followed by hot pressing with TiO2, Al, C and ZrO2 as raw materials. Combustion synthesis is favorable to obtain in situ formed powder with TiC and ZrO2 nanoparticles distributed in Al2O3 matrix. The effects of varying amount of ZrO2 nano-scale additives on the mechanical properties and microstructure of Al2O3-TiC composite were studied. An appropriate amount of ZrO2 nanoparticle additive improves the mechanical properties. The flexural strength and fracture toughness of Al2O3-TiC-10 wt.% ZrO2 composite were approximately 20% higher than that of Al2O3-TiC composite. The addition of ZrO2 nanoparticles reduced the grain size and improved the distribution of different phases. With the ZrO2 addition, the fracture mode changes from intergranular to mixed inter/transgranular fracture. The residual stresses are generated by the thermal expansion coefficient mismatch between different phases, which leads to the generation of dislocations and microcracks around the nanoparticles. The effects of nanoparticles on the deflected propagation, nailing and blocking of the dislocation and microcracks are believed to contribute to the improvement of the strength and toughness of Al2O3-TiC-ZrO2 composite.

  • 24.
    Femenia, Marc
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Corrosion Studies of Duplex Stainless Steels with Micrometer Resolution2004In: Journal of Corrosion Science & Engineering, ISSN 1466-8858, E-ISSN 1466-8858, Vol. 6, p. paper 28-Article in journal (Refereed)
    Abstract [en]

    The local corrosion behavior of duplex stainless steel (DSS) is affected by a wide variety of factors. Localized corrosion of DSS frequently starts at micrometer scale inclusions or precipitates, which are often segregated in the austenite-ferrite boundary regions. Moreover, due to the partitioning of the key alloying elements of ferrite (Cr and Mo) and austenite (N and Ni), the local interactions between the phases must also be considered. The aim of this doctoral study was to increase the knowledge about the local dissolution behavior of DSS in acidic-chloride environments. The recent developments of new local probing techniques have opened a new frontier in corrosion science, providing valuable local information not accessible in the past. The local techniques used include electrochemical scanning tunneling microscopy (EC-STM), scanning probe force microscopy (SKPFM), magnetic force microscopy (MFM), and scanning Auger electron Spectroscopy (SAES), all with micrometer or sub-micrometer resolution. With EC-STM, it was possible to monitor local dissolution processes on DSS in situ, and in real time. MFM was capable of imaging the phase distribution in DSS without the need of the traditional surface etching, while SKPFM revealed that the Volta potential difference between the two phases was measurable and significant. SAES showed that the composition gradient at the phase boundaries is narrower than 2 µm. Different types of DSSs have been studied, from low-alloyed DSS to superduplex. Higher contents of Cr, Mo and N strengthened both phases as well as the phase boundaries, resulting in phases having similar corrosion resistance that showed a more uniform dissolution behavior. However, the Volta potential difference between the phases proved to be of the same order for all the DSSs studied. Austenite was in general associated to regions displaying a more noble Volta potential than ferrite, resulting in a higher dissolution rate of the ferrite next to the austenite phase.

  • 25. Forsberg, J.
    et al.
    Duda, L. C.
    Olsson, A.
    Schmitt, T.
    Andersson, J.
    Nordgren, J.
    Hedberg, J.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Aastrup, T.
    Wallinder, D.
    Guo, J. H.
    System for in situ studies of atmospheric corrosion of metal films using soft x-ray spectroscopy and quartz crystal microbalance2007In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 78, no 8Article in journal (Refereed)
    Abstract [en]

    We present a versatile chamber (atmospheric corrosion cell) for soft x-ray absorption/emission spectroscopy of metal surfaces in a corrosive atmosphere allowing novel in situ electronic structure studies. Synchrotron x rays passing through a thin window separating the corrosion cell interior from a beamline vacuum chamber probe a metal film deposited on a quartz crystal microbalance (QCM) or on the inside of the window. We present some initial results on chloride induced corrosion of iron surfaces in humidified synthetic air. By simultaneous recording of QCM signal and soft x-ray emission from the corroding sample, correlation between mass changes and variations in spectral features is facilitated.

  • 26. Forsberg, J.
    et al.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Nordgren, J.
    Duda, L. C.
    The Initial Stages of Atmospheric Corrosion of Iron in a Saline Environment Studied with Time-Resolved In Situ X-Ray Transmission Microscopy2010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 3, p. C110-C115Article in journal (Refereed)
    Abstract [en]

    We have investigated atmospheric corrosion of a 50 nm layer of iron covered with a thin layer of NaCl by in situ X-ray transmission spectromicroscopy. We find that upon its deliquescence, a small part of the NaCl layer is rapidly transformed into a sodium oxide (NaOH) species. A large part of the sodium and chlorine ions forms a concentrated solution on the iron surface and becomes segregated, whereby the sodium ions appear stationary and passive during further corrosion progression. In contrast, the chlorine ions appear highly mobile and become concentrated at and travel with the corrosion front, apparently acting as a corrosion catalyst. The corrosion front progression is partly of filiform and partly of radial type. The early iron corrosion products (chloride-containing oxyhydroxides) are short-lived (for some hours) and undergo a transformation as the corrosion front sweeps by from a chlorinated species to a less chlorinated species.

  • 27.
    Gil, Harveth
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Quantitative in situ analysis of initial atmospheric corrosion of copper induced by acetic acid.2007In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 154, no 5, p. 272-278Article in journal (Refereed)
    Abstract [en]

    The initial atmospheric corrosion of copper was investigated by means of a quantitative in situ analysis in an atmospherecontaining 120 ppb of acetic acid and 95% relative humidity using a quartz crystal microbalance (QCM) integrated with infraredreflection absorption spectroscopy (IRAS). Crystalline cuprous oxide (various structural forms of Cu2O) and hydrated copperacetate were detected as corrosion products during up to 100 h of exposure. The quantification of data was made possible throughan observed linear relationship between the absorbance of vibrations (IRAS)of both phases and the corresponding mass (QCM).The quantification of cuprous oxide was further supported by ex situ coulometric reduction of the corrosion products. The growthrate of cuprous oxide was initially very fast but almost zero after 20 h exposure where it reached an average thickness of13 ± 1 nm. Copper acetate exhibited a more constant growth rate. Atomic force microscopy showed a uniform growth of cuprousoxide with surface roughness that increased with time and localized formation of copper acetate. The quantified data are consistentwith a previously proposed model that involves proton- and acetate-induced dissolution of copper and subsequent precipitation ofcuprous oxide and copper acetate.

  • 28.
    Gil, Harveth
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christopher
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Initial atmospheric corrosion of copper induced by carboxylic acids2007In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 154, no 11, p. C611-C617Article in journal (Refereed)
    Abstract [en]

    A procedure based on infrared reflection absorption spectroscopy integrated with a quartz crystal microbalance has been developed and used for comparison of initial atmospheric corrosion of copper induced by formic, acetic, and propionic acid. The absolute mass of individual constituents of corrosion products formed, mainly cuprous oxide or cuprite, copper carboxylate, and water or hydroxyl groups, could be obtained under in situ conditions during exposure in 120 ppb of carboxylic acid concentration, 95% relative humidity, 20 degrees C, and up to 96 h of exposure. The quantitative data exhibit consistency between all acids and with postanalysis performed by coulometric reduction. Two spatially separated main pathways have been identified: a proton-induced dissolution of cuprous ions followed by the formation of copper(I) oxide, and a carboxylate-induced dissolution followed by the formation of copper(II) carboxylate. The first pathway is initially very fast but levels off, grows more uniformly over the surface, and dominates in acetic acid. The second pathway exhibits a more constant growth rate and localized growth, and dominates in formic acid. Propionic acid exhibits low rates for both pathways. The difference between the carboxylic acids with respect to both total corrosion rate and carboxylate-induced dissolution can be attributed to their dissociation constants and deposition velocity.

  • 29. Goidanich, S.
    et al.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Arenas, M. A.
    De Damborenea, J.
    Ormellese, M.
    Sánchez Amaya, J. M.
    Botana, F. J.
    Le Bozec, N.
    Effect of the environment on the metal release and corrosion behaviour of different copper-based alloys: Field exposures at 5 different test sites in Europe2008Conference paper (Refereed)
    Abstract [en]

    Diffuse emissions and dispersion of metals from different sources in the society have lately received an increased concern from an environmental perspective. Large research efforts have been initiated and undertaken by the division of Corrosion Science at KTH to fill knowledge gaps on corrosion-induced metal release from external constructions and buildings. The generation of such data is of paramount importance for the on-going assessment of flows and potential adverse environmental effects caused by released metals. Generated information is also essential for an improved understanding of prevailing atmospheric corrosion processes of importance for the preservation of our cultural heritage, e.g. bronze statues exposed to the atmosphere. This paper summarizes and compares long-term metal release data from pure copper, bronze (6%wt Sn) and brass (20%wt Zn) exposed at unsheltered conditions in five European environments of significantly different climatic and pollutant conditions; three urban sites (Stockholm-Sweden, Milan-Italy and Madrid-Spain) and two marine sites (Brest-France, Cadiz-Spain). Generated data are interpreted with respect to parallel multi-analytical studies of changes in patina characteristics, corrosion rates and differences in prevailing environmental conditions.

  • 30.
    Goidanich, Sara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Wallinder, Inger Odnevall
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Corrosion induced metal release from copper based alloys compared to their pure elements2008In: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 43, no 2, p. 134-141Article in journal (Refereed)
    Abstract [en]

    Despite numerous studies on atmospheric corrosion of copper and copper based alloys, the corrosion induced release processes of individual alloy constituents suffer from significant knowledge gaps. This investigation comprises metal release rate measurements of copper, zinc and tin from some copper based alloys including brass (20 wt-% Zn) and bronze (6 wt-% Sn), and their pure alloying metals, copper, zinc and tin. Data have been generated during a 2.5 year urban field exposure in Stockholm, Sweden and parallel laboratory investigations in a specially designed rain chamber using artificial rain. Brass shows significantly lower annual release rates of both copper and zinc compared to pure metal sheets of its alloy constituents. Zinc is preferentially released compared to copper. Dezincification of brass occurs both at field and laboratory conditions, a process influenced by rain characteristics. Alloying with tin does not largely reduce the release rate of copper from bronze compared to pure copper. No measurable amount of tin is released from the bronze surface.

  • 31. He, W
    et al.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Runoff Rates of Zinc - a Four-Year Field and Laboratory Study: American Society for Testing and Materials2002In: Outdoor Atmospheric Corrosion / [ed] Herbert E Townsend, ASTM International, 2002, p. 216-Chapter in book (Refereed)
  • 32.
    Hedberg, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Baldelli, Steven
    Department of Chemistry, University of Houston.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Evidence for the Molecular Basis of Corrosion of Zinc Induced by Formic Acid using Sum Frequency Generation Spectroscopy2010In: Journal of Physical Chemistry Letters, ISSN 1948-7185, Vol. 1, no 10, p. 1679-1682Article in journal (Refereed)
    Abstract [en]

    In situ observations of surface hydroxyl groups and the subsequent ligand exchange during initial atmospheric corrosion conditions of Zn are reported. The data have been obtained with sum frequency generation spectroscopy (SFG) during exposure of polycrystalline zinc to humidified or dry nitrogen gas, N-2, to which 100 parts per billion of formic acid, HCOOH, was added. The SFG data provide evidence of surface hydroxyl groups and their gradual replacement by formate species through a ligand exchange, representing the initial step of formate-induced dissolution of zinc. In addition, the aqueous adlayer on the Zn surface is probed, and the occurrence of the free OH vibration confirms a bulk-like water film.

  • 33.
    Hedberg, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Baldelli, Steven
    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.
    Molecular Structural Information of the Atmospheric Corrosion of Zinc Studied by Vibrational Spectroscopy Techniques II. Two and Three-Dimensional Growth of Reaction Products Induced by Formic and Acetic Acid2010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 10, p. C363-C373Article in journal (Refereed)
    Abstract [en]

    In an effort to obtain a more molecular view of atmospheric corrosion, we present experimental data from three complementary acting vibrational spectroscopy techniques that have been used in parallel exposures to follow the initial atmospheric corrosion of zinc during exposure in dry or humid air to which formic acid or acetic acid was added, with the primary aim to simulate indoor exposure conditions. The techniques used were vibrational sum frequency spectroscopy (interface sensitive), IR reflection absorption spectroscopy (near-surface sensitive), and confocal Raman microspectroscopy (bulk sensitive with submicrometer surface lateral resolution). The growth of two-dimensional interface species of zinc formate or zinc acetate could be monitored in situ and distinguished from three-dimensional growth of ZnO and zinc hydroxy formate or acetate. These interface species are believed to act as precursors of the dissolution of aqueous zinc carboxylate species that subsequently deposit at the surface and result in local growth of crystalline or amorphous ZnO and local zinc hydroxy carboxylate. Differences in the growth of corrosion products induced by acetic or formic acid were mainly attributed to differences in pH of the aqueous adlayer and in different deposition velocities of the acids into the aqueous adlayer. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479255] All rights reserved.

  • 34.
    Hedberg, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Baldelli, Steven
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Tyrode, Eric
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Molecular Structural Information of the Atmospheric Corrosion of Zinc Studied by Vibrational Spectroscopy Techniques I. Experimental Approach2010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 10, p. C357-C362Article in journal (Refereed)
    Abstract [en]

    As the nature of the interactions taking place on a metal surface during atmospheric corrosion is inherently complex, it imposes demands on the analytical studies that are needed to understand the fundamentals on a molecular level. Corrosion products may spread on the metal surface forming two-and three-dimensional structures. Thus, it is imperative to use different techniques to resolve the different types of growth. In this first part of a series of two papers, a systematic investigation is made to obtain detailed information on the mechanisms of the onset of atmospheric corrosion of zinc exposed to 115 ppb acetic acid in either dry or humidified air. The vibrational spectroscopy techniques used were vibrational sum frequency spectroscopy (VSFS, interface sensitive), infrared reflection absorption spectroscopy (IRAS, near-surface sensitive), and confocal Raman microspectroscopy (CRM, bulk sensitive). The VSFS selectively targeted the two-dimensional structures, IRAS followed the growth of three-dimensional corrosion products, and CRM could provide a laterally resolved chemical map on localized aggregates of zinc hydroxy acetate and ZnO with bulk character. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479207] All rights reserved.

  • 35.
    Hedberg, Jonas F.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Qiu, Ping
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Vibrational sum frequency spectroscopy for in situ studies of initial atmospheric corrosion of zinc induced by formic acid2008In: Int. Corros. Congr.: Corros. Control Serv. Soc., 2008, p. 1536-1541Conference paper (Refereed)
    Abstract [en]

    With the access and recent development of interface sensitive analytical techniques, it has become possible to perform molecular in situ analyses of the interfaces involved under ambient atmospheric pressure conditions. The initial indoor atmospheric corrosion of zinc has been investigated by vibrational sum frequency spectroscopy (VSFS). Vibrational sum frequency spectroscopy is an inherent surface sensitive technique which also gives information on the ordering of the molecules. It is used herein for probing the interface between the metal and the spontaneously formed aqueous adlayer. The zinc was exposed to humidified air to which formic acid (HCOOH) was added as corrosion stimulant. VSFS showed evidence of formate on the surface after exposure to 120 ppb formic acid, and the structure of the surface formates were seen to stabilize within approximately 90 minutes of exposure. This is in contrast with near-surface probing Infra red reflection absorption spectroscopy (IRAS) results which monitors a continuous increase in zinc formates beyond 90 minutes of exposure to formic acid and humid air. These results form evidence that the structure of the surface formates stays the same beyond 90 minutes of exposure, even though there is an ongoing corrosion process, as seen by the growth of the thin film of formates.

  • 36.
    Hedberg, Jonas
    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, Corrosion Science.
    Adsorption and Structure of Octadecanethiol on Zinc Surfaces As Probed by SumFrequency Generation Spectroscopy, Imaging, and Electrochemical Techniques2007In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 47, p. 17587-17596Article in journal (Refereed)
    Abstract [en]

    Octadecanethiol (ODT) adsorbed onto zinc has been studied with sum frequency generation (SFG), sum frequency generation imaging microscopy (SFG-IM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS) in order to investigate its corrosion protective ability and conformational ordering. SFG shows that ODT forms an ordered adsorbate on both reduced and oxidized zinc within short times after immersion in 1 mM ODT/ethanol solution. The corrosion protection, deduced by EIS, is also improved after immersion in the ODT solution. After longer immersion times, the corrosion protection decreases as well as the conformational order of the adsorbed ODT. Increasing the ODT concentration avoids this degradation with prolonged immersion time. The ODT is seen in the XPS spectra to adsorb to the reduced as well as the oxidized zinc by forming a Zn-S bond for both short and long immersion times. The SFG-IM completes the picture, showing a heterogeneous surface with areas corresponding to ordered ODT as well as disordered or uncovered regions. The density of adsorbed ODT after 24 h immersion time for both reduced and oxidized zinc was deduced from CV and was found to be approximately 6.7 x 10(-9) mol/cm(2).

  • 37.
    Hedberg, Jonas
    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, Corrosion Science.
    Initial Atmospheric Corrosion of Zinc Exposed to Formic Acid, Investigated by in Situ Vibrational Sum Frequency Spectroscopy and Density Functional Theory Calculations2008In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, p. 2088-2095Article in journal (Refereed)
    Abstract [en]

    Vibrational sum frequency spectroscopy (VSFS) and ab initio density functional theory (DFT) calculations of formic acid on ZnO/Zn have been performed in order to understand the first step of atmospheric corrosion on zinc initiated by formic acid. In addition, infrared reflection absorption spectroscopy (IRAS) has been employed to complement the surface sensitive VSFS results to identify the corrosion products. Oxidized polycrystalline zinc samples were exposed to 120 ppb formic acid in either humid or dry Air where, the formic acid adsorption on ZnO/Zn is observed to have a low dependence on the humidity, as deduced by VSFS. Formate is formed on the surface in both dry and humid air and stabilized in configuration after about 90 min exposure in 120 ppb formic acid as seen in the VSFS results. This is evidenced by the occurrence of the CH and symmetric COO- vibrations of the formate ion. The DFT calculations support the VSFS results, showing a coordination of the formate to zinc ions without participation from water molecules.

  • 38.
    Hedberg, Jonas
    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, Corrosion Science.
    Initial Atmospheric Corrosion of Zn: Influence of Humidity on the Adsorption of Formic Acid Studied by Vibrational Sum Frequency Spectroscopy2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, p. 6169-6173Article in journal (Refereed)
    Abstract [en]

    The ZnO/Zn surface exposed to formic acid undergoes a partial, reversible dissociation to formate ion, and a protonated surface oxide and is seen to have different hydration states depending on the relative humidity. Under high relative humidity conditions it exists as a formate coordinated to the surface with the oxygen atoms toward the surface and the C-H directed away into the vapor. In a dry environment a formic acid/formate intermediate is formed, although a substantial amount of dissociated species still are present, in both hydrated and nonhydrated form. The results may have implications on the initial atmospheric corrosion of Zn and emphasize that the ZnO/Zn surface is heterogeneous with a range of acid and basic sites for the adsorption of formate and the proton.

  • 39.
    Hedberg, Jonas
    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, Corrosion Science.
    Molecular in-situ observations of hydroxyl groups and ligand exchange during initial atmospheric corrosionManuscript (preprint) (Other academic)
  • 40.
    Hedberg, Jonas
    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, Corrosion Science.
    Molecular structural information of the atmospheric corrosion of zinc studied by vibrational spectroscopy techniques: Part I. Experimental approachManuscript (preprint) (Other academic)
  • 41.
    Hedberg, Jonas
    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, Corrosion Science.
    Molecular structural information of the atmospheric corrosion of zinc studied by vibrational spectroscopy techniques: Part II. Two and three dimensional growth of reaction products induced by formic and acetic acidManuscript (preprint) (Other academic)
  • 42.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Dromberg, P.
    Water and Sewage Network Investigations, Stockholm Vatten VA AB.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Die Bindekapazität von Entwässerungssystemen für Kupfer von Kupferdächern: Vergleich von Regenwasserkupferkonzentrationen in einem Kupferdachentwässerungssystem und einem Parkplatz2010In: Wasser- /Abwassertechnik, Vol. 3, p. 22-23Article in journal (Other (popular science, discussion, etc.))
  • 43.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Wallinder, Inger Odnevall
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Risks of using membrane filtration for trace metal analysis and assessing the dissolved metal fraction of aqueous media - A study on zinc, copper and nickel2011In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 159, no 5, p. 1144-1150Article in journal (Refereed)
    Abstract [en]

    Membrane filtration is commonly performed for solid liquid separation of aqueous solutions prior to trace metal analysis and when assessing "dissolved" metal fractions. Potential artifacts induced by filtration such as contamination and/or adsorption of metals within the membrane have been investigated for different membrane materials, metals, applied pressures and pre-cleaning steps. Measurements have been conducted on aqueous solutions including well-defined metal standards, ultrapure water, and on runoff water from corroded samples. Filtration using both non-cleaned and pre-cleaned filters revealed contamination and adsorption effects, in particular pronounced for zinc, evident for copper but non-significant for nickel. The results clearly show these artifacts to be non-systematic both for non-cleaned and pre-cleaned membranes. The applied pressure was of minor importance. Measurements of the labile fraction by means of stripping voltammetry clearly elucidate that membrane filtration followed by total metal analysis cannot accurately assess the labile or the dissolved metal fraction.

  • 44.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Protective green patinas on copper in outdoor constructions2011In: Journal of Environmental Protection, ISSN 2152-2197, E-ISSN 2152-2219, Vol. 2, no 7, p. 956-959Article in journal (Refereed)
    Abstract [en]

    The last 15 years of research related to atmospheric corrosion and the release of copper to the environment are shortly summarized. Brown and green patinas with high barrier properties for corrosion are gradually evolved on copper at atmospheric conditions. The corrosion process and repeated dry and wet cycles results in a partial dissolution of cor-rosion products within the patina. Dissolved copper can be released and dispersed into the environment via the action of rainwater, however the major part is rearranged within the patina during drying cycles. The majority of corrosion products formed have a poor solubility, very different from water soluble copper salts. The release process is very slow and takes place independent of patina color. Its extent has only a marginal effect on the adherent patina. Released cop-per rapidly interacts with organic matter and in contact with different surfaces already in the close vicinity of the building, such as drainage systems, storm water pipes, pavements, stone materials and soil systems. These surfaces all have high capacities to retain copper in the runoff water and to reduce its concentration and chemical form to non-available and non-toxic levels for aquatic organisms.

  • 45.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Bioaccessibility of Stainless Steels: Importance of Bulk and Surface Features2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    With increasing environmental awareness, the desire to protect human beings and the environment from adverse effects induced by dispersed metals has become an issue of great concern and interest. New policies, such as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) within the European Community, have been implemented to reduce hazards posed by the use of chemicals on producers and downstream users. The generation of exposure assessment data and relevant test procedures able to simulate realistic scenarios are essential in such legislative actions.

    This doctoral study was initiated to fill knowledge gaps related to the metal release process of stainless steels. A wide range of stainless steel grades, fourteen in total, were investigated. They cover a very broad range of applications, and the focus in the thesis was to simulate a few selected exposure scenarios: precipitation, the human body and food intake. Comparisons were made between metal release from stainless steel alloys and the pure metals that constitute each stainless steel in order to explore the differences between alloys and pure metals, and to provide quantitative data on metal release rates of different alloy constituents. Because of similar surface properties between stainless steel and pure chromium, this metal exhibits similar release rates, whereas iron and nickel exhibit significantly lower release rates as alloy components than as pure metals. Detailed studies were also performed to elucidate possible relations between metal release and steel surface properties. Key parameters turned out to be chromium enrichment of the self-passivating surface film, surface roughness, the electrochemically active surface area and the microstructure of the steel substrate. The degree of metal release increased with decreasing chromium content in the surface oxide, increasing surface roughness, and increasing presence of inhomogeneities in the bulk matrix.

    More detailed studies were initiated to possibly correlate the nucleation of metastable pits and the extent of metal release. Evidence was given that metastable pits exist even when the stainless steel is passive, and may cause extremely short-lived bursts of released metal before the surface film repassivates again.

  • 46.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Goidanich, Sara
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Corrosion-induced release of Cu and Zn into rainwater from brass, bronze and their pure metals. A 2-year field study2008In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 144, no 1-3, p. 455-461Article in journal (Refereed)
    Abstract [en]

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

  • 47.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Jiang, Tao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Material characterization and elemental release studies in synthetic biological media, and OECD Transformation Dissolution protocol studies of ferrosilicon alloys2010Report (Other academic)
  • 48.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Jiang, Tao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Material characterization and elemental release studies insynthetic biological media, and in the OECDTransformation Dissolution protocol media: Silicon2010Report (Other (popular science, discussion, etc.))
  • 49.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Jiang, Tao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Material characterization and elemental release studies insynthetic biological media, and OECD TransformationDissolution protocol studies of a ferrosilicocalcium alloy: CaSi2010Report (Other (popular science, discussion, etc.))
  • 50.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Influence of Surface Finish on Stainless Steel AISI 304 on the Metal Release Process in Synthetic Biological Media2008Conference paper (Refereed)
    Abstract [en]

    The objective of this study is to illuminate differences in metal release rates between varioussurface finishes on stainless steel. A large range of finishes exist on the market, and varies depending onarea of application and aesthetic appearance. The influence of surface finish is examined andexemplified using stainless steel grade AISI 304 in terms of individual metal release rates of the mainalloying elements: chromium, nickel and iron using inductively coupled plasma-mass spectrometry,ICP-MS, differences in the electrochemically active surface area using electrochemical impedancespectroscopy, EIS, and changes in surface composition of the outermost surface oxide using x-rayphotoelectron spectroscopy, XPS. The study includes five different cold-rolled surface finishes, threecommercial surfaces, BA, 2B and 2D (as described in the Euronorm and ASTM specifications), oneelectropolished surface, and one electropolished and passivated surface, all separately immersed in asynthetic body fluid (artificial lysosomal fluid, pH 4.5), and sampled after 8 and 168 hours at 37 ºC.The electrochemically active surface area is found to have a significant influence on the total metalrelease rate, increasing as follows: electropolished and passivated < electropolished < BA ≈ 2B < 2D.

123 1 - 50 of 135
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