| 1. |
- Le Calvé, Philippe, et al.
(författare)
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Influence of UHP waterjetting on shop-primed steel in new construction, Part 3
- 2012
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Ingår i: Journal of Protective Coatings and Linings. - 8755-1985. ; 29:8, s. 42-53
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Tidskriftsartikel (refereegranskat)abstract
- Ultra-high-pressure (UHP) waterjetting is becoming more common for coatings on steel structures. An effort was made to design an appropriate welded sample, including a mixed zone at the periphery of the weld seam cleaned by UHP waterjetting to get a cleanliness DHP4. Three different paint systems were applied on the various panel design and roughnesses, and they were exposed to cyclic corrosion tests and natural weathering. Two designs of test panels were considered, flat panels and welded panels. The flat panels were then cleaned by UHP waterjetting on only one side, to treatment degree DHP1, light cleaning according to NF T 35-520 standard. The corrosion performance of the paint systems as a function of surface preparation was carried out in the laboratory. No degradation such as blistering, rusting, cracking, and chalking was observed on any of the paint systems. However, a loss of brightness was seen on S2 paint systems.
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| 2. |
- Nazarov, Andrej, et al.
(författare)
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Scanning kelvin probe investigation of corrosion under thick marine paint systems applied on carbon steel
- 2012
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Ingår i: Corrosion. - : NACE International. - 0010-9312 .- 1938-159X. ; 68:8, s. 720-729
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Tidskriftsartikel (refereegranskat)abstract
- The scanning Kelvin probe (SKP) is a non-destructive technique for measuring the surface distribution of the Volta potential with a high spatial resolution of a few tens of micrometers. The SKP technique allows in situ studies of the localized corrosion processes under atmospheric weathering conditions, on metal surfaces, or underneath organic coatings. In the present study, the SKP technique was used to follow the kinetics of underpaint corrosion from a defect applied on steel coated with thick marine paint systems (0.4 mm to 0.5 mm) as a function of exposure time in an accelerated corrosion test. Three different paint systems were investigated. In addition, the influence of surface cleanliness in terms of salt concentration on a steel substrate prior to paint application was investigated using the SKP technique. The results showed the high efficiency of the SKP technique for early corrosion evaluation under thick paints on steel substrate.
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| 3. |
- Thierry, Dominique, et al.
(författare)
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Recent advance in corrosion monitoring of atmospheric corrosion
- 2019
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Ingår i: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13124Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019. - : National Assoc. of Corrosion Engineers International.
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Konferensbidrag (refereegranskat)abstract
- A compact and autonomous corrosion sensor using the principle of electrical resistance variations of its metallic sensitive tracks has been used for different applications under atmospheric corrosion conditions. The measurements of the corrosion rate are performed in-situ both under laboratory and field exposures. From the results, it is possible to better understand the atmospheric corrosion of steel and zinc under various exposure conditions. The technique should also allow the design of reliable and realistic corrosion tests for different industrial applications.
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| 4. |
- Becker, Johan, et al.
(författare)
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Atmospheric corrosion of silver, copper and nickel exposed to hydrogen sulphide : a multi-analytical investigation approach
- 2022
-
Ingår i: Corrosion Science. - : Elsevier Ltd. - 0010-938X .- 1879-0496. ; 209
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Tidskriftsartikel (refereegranskat)abstract
- The effect of two concentrations of H2S (0.5 and 2.5 ppm), in controlled laboratory conditions (20 °C, 75%RH), on the atmospheric corrosion of pure Ag, Cu and Ni was investigated in this study. The corrosion product morphology and composition were analysed through a multi-technique approach including SEM/EDX, Raman spectroscopy, XPS and XRD. Different corrosion products were identified depending on the type of characterisations providing a better overview of the effect of H2S on the atmospheric corrosion of pure Ag, Cu and Ni. Possible mechanisms involved in the formation of these corrosion products are also discussed in this work. © 2022 The Authors
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| 5. |
- Caussé, Nicolas, et al.
(författare)
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Ageing processes of coil-coated materials : Temperature-controlled electrochemical impedance analysis
- 2023
-
Ingår i: Progress in organic coatings. - : Elsevier B.V.. - 0300-9440 .- 1873-331X. ; 183
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, an industrial polyester coil-coated steel was characterized by electrochemical impedance spectroscopy (EIS) during immersion in a 0.5 M NaCl solution for different temperatures (30, 40, 50 and 60 °C). The objective was to propose a methodology to follow the ageing of the coil-coated system, from the first stage of water uptake until the blistering appearance. Relevant parameters were extracted from the EIS diagrams to analyse ageing processes of the polymer and of the metal/polymer interface. Water uptake was determined from the high-frequency part of the impedance diagrams using a linear rule of mixtures. By increasing the temperature, both the water uptake kinetics and the water content in the coating increased. The effect of water uptake on the physical structure of the coating (plasticization) was discussed through the analysis of a time constant corresponding to the dielectric manifestation of the polymer glass transition. At 40, 50 and 60 °C, appearance of corrosion was detected on the impedance spectra by a decrease, at low frequency, of the impedance modulus and of the phase angle. For 60 °C, the corroded surface area as a function of time, was assessed from the EIS data analysis with adapted equivalent circuits. The corroded surface areas followed similar trend as blister surface areas determined from images analysis.
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| 6. |
- Chang, Tingru, et al.
(författare)
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The role of Sn on the long-term atmospheric corrosion of binary Cu-Sn bronze alloys in architecture
- 2019
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Ingår i: Corrosion Science. - : Elsevier Ltd. - 0010-938X .- 1879-0496. ; 149, s. 54-67
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Tidskriftsartikel (refereegranskat)abstract
- The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4–6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern. © 2019 The Authors
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| 7. |
- Even, Anais, et al.
(författare)
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Influence of radical photoinitiator content on UV curing process and UV-cured hybrid sol–gel films
- 2020
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Ingår i: JCT Research. - : Springer. - 1547-0091 .- 2168-8028. ; 17:2, s. 333-343
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid sol–gel coatings are widely used as protective layers for aluminum alloys because of their barrier abilities. This study aims at explaining the barrier properties of a sol–gel coating based on alkyltrimethoxysilane and methacrylate resin by its film structure. This approach was examined by modifying one photopolymerization parameter, e.g., by varying the content of radical photoinitiator. By neutral salt spray test and electrochemical impedance spectroscopy, the barrier properties are highlighted. The film structure is related to thermomechanical properties of films whose glass transition temperature and elastic modulus are measured by dynamic mechanical analysis and nanoindentation, respectively. On a finer scale, conversion of methacrylate functions calculated from Fourier transform infrared spectroscopy has given information on the chemical structure of films. The morphology of these coatings is studied by scanning electron microscopy, transmission electron microscopy, atomic force microscopy operating in tapping mode, and X-ray diffraction. Results revealed that formulations containing between 3 and 9 wt% of radical photoinitiator exhibit the maximal conversion of methacrylate functions and, at a microscopic scale, a homogeneous coating where the two organic and inorganic networks are well interpenetrated. This hybrid sol–gel microstructure corresponds to the highest glass transition temperature and the highest mechanical characteristics (elastic modulus, E and hardness, H) and the highest protection performance. This results in the best barrier properties, and thus the highest corrosion resistance.
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| 8. |
- Goidanich, S., et al.
(författare)
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Effect of the environment on the metal release and corrosion behaviour of different copper-based alloys : Field exposures at 5 different test sites in Europe
- 2008
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Ingår i: 17th International Corrosion Congress 2008. - 9781615674251 ; , s. 102-115
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 9. |
- Hedberg, Jonas, et al.
(författare)
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Spatial distribution and formation of corrosion products in relation to zinc release for zinc sheet and coated pre-weathered zinc at an urban and a marine atmospheric condition
- 2013
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Ingår i: Materials and corrosion - Werkstoffe und Korrosion. - : Wiley. - 0947-5117 .- 1521-4176. ; 64:4, s. 300-308
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Tidskriftsartikel (refereegranskat)abstract
- Zinc release data from 5 years of unsheltered exposures in a marine and an urban site is compiled for different zinc material types. The thin surface treatment on zinc materials is gradually detached after approximately 2 years at both sites, revealing the pre-weathered zinc surface unprotected. This consequently increased the release rates of zinc from this surface, whereas the zinc runoff rate from the bare zinc sheet remained relatively stable. Raman studies on bare zinc sheet exposed for 5 years at the marine site revealed zinc oxide of varying crystalline nature and hydrozincite to appear localized and separated from each other.
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| 10. |
- Helbert, Varvara, et al.
(författare)
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Corrosion behavior of additively manufactured AISI 316L stainless steel under atmospheric conditions
- 2022
-
Ingår i: Materials and corrosion - Werkstoffe und Korrosion. - : John Wiley and Sons Inc. - 0947-5117 .- 1521-4176. ; 73:11, s. 1833-
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the corrosion behavior of AISI 316L produced by direct energy deposition (DED). Microstructural and chemical analysis showed a homogeneous distribution of Si and Si–Mn inclusions of 0.5–1 µm and the Cr and Mo enrichment within interdendritic areas. Scanning Kelvin probe analysis of additively manufactured stainless steel highlighted a regular “striped-like” surface potential feature with a potential gradient of 30 mV for a mean value of 0.320 ± 0.017 V versus standard hydrogen electrode. It can be related to the presence of the residual stress in the oxide film and the complex thermal history due to the fabrication process. A cyclic corrosion test simulating atmospheric conditions revealed the same corrosion properties for stainless steel fabricated by DED compared to cold rolled one. Various surface preparations of 316L were also exposed for corrosion tests. It was found that the “as-received” and “brushed” surfaces exhibited poorer corrosion resistance due to the presence of an as-build defective layer. However, prior passivation of brushed surface, machining, or mechanical grinding down to P1200 improve significantly the corrosion resistance. © 2022 French Corrosion Institute part of RISE Research Institutes of Sweden. Materials and Corrosion published by Wiley-VCH GmbH.
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| 11. |
- Le Bozec, Nathalie, et al.
(författare)
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The role of chromate conversion coating in the filiform corrosion of coated aluminum alloys
- 2003
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 150:12, s. B561-B566
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms of inhibition of chromate conversion coating on the filiform corrosion of coated aluminum alloy AA6016 was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and Raman microspectroscopy. The results showed that Cr(VI) was preferably leached out at the opening of the filament, whereas Cr(VI) was reduced to Cr(III) at all other locations. The leached out Cr(VI) accumulated mainly in the pitting area, located in the scratch just outside the filament. The chromate released from the CCC was partly reduced to Cr(III) in the pit. The formation of an Al/Cr mixed oxide was observed in the pitting area. The repassivation of pits in the scratch by the chromate leaching from the CCC close to the scratch explains the low propagation of filiform corrosion observed for the chromated surfaces.
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| 12. |
- Nazarov, Andrej, et al.
(författare)
-
Assessment of steel corrosion and deadhesion of epoxy barrier paint by scanning Kelvin probe
- 2018
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Ingår i: Progress in organic coatings. - : Elsevier B.V.. - 0300-9440 .- 1873-331X. ; 114, s. 123-134
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 13. |
- Nazarov, Andrej P., et al.
(författare)
-
Protective action of vanadate at defected areas of organic coatings on zinc
- 2005
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 152:7, s. B220-B227
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 14. |
- Nazarov, Andrej, et al.
(författare)
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Scanning Kelvin Probe assessment of steel corrosion protection by marine paints containing Zn-rich primer
- 2018
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Ingår i: Progress in organic coatings. - : Elsevier B.V.. - 0300-9440 .- 1873-331X. ; 125, s. 61-72
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 15. |
- Odnevall Wallinder, Inger, et al.
(författare)
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Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 472, s. 681-694
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Tidskriftsartikel (refereegranskat)abstract
- Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn > Cu sheet > Cu15Zn > Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu-2(OH)(3)Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn-5(OH)(6)(CO3)(2) (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)(16)CO3 center dot 4H(2)O/Zn2Al(OH)(6)Cl center dot 2H(2)O/Zn5Cl2(OH)8 center dot H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu-2(OH)(3)Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties.
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| 16. |
- Pélissier, Krystel, et al.
(författare)
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Evaluation of the Long-Term Performance of Marine and Offshore Coatings System Exposed on a Traditional Stationary Site and an Operating Ship and Its Correlation to Accelerated Test
- 2022
-
Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 12:11
-
Tidskriftsartikel (refereegranskat)abstract
- Anticorrosive coatings are widely used to protect steel against corrosion. Different standards exist to access the corrosion performance of anticorrosive paints. Among them, the so-called neutral salt spray test (NSST-ISO 9227) or cycling corrosion tests ISO 12944-6, ISO 12944-9, NACE TM0304, or NACE TM0404 can be named. It is well-known that some accelerated corrosion tests are not fully representative of the field exposure results. However, a lack in the literature exists correlating accelerated tests to field exposure, especially when long-term durations are considered. In this study, 11 different organic coatings have been investigated in terms of coating resistance to corrosion creep in two types of field exposure sites, namely a stationary site and an operating ship, and their performance was compared to two accelerated tests (ISO 12944-9 and modified ASTM D5894 standard). The results showed differences in the sites’ corrosivity and the coating systems’ performance as a function of the exposure sites. A lack of correlation exists between the ISO 12944-9 standard and the stationary site, due to the latter’s high corrosivity, while, to the contrary, a satisfying correlation with the operating ship was demonstrated; whereas, the modified ASTM D5894 standard showed a satisfying correlation with both types of sites.
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| 17. |
- Persson, Dan, et al.
(författare)
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The Effect of Microstructure on Local Corrosion Product Formation during Initial SO2-Induced Atmospheric Corrosion of ZnAlMg Coating Studied by FTIR-ATR FPA Chemical Imaging
- 2023
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Ingår i: Corrosion and Materials Degradation. ; 4:3, s. 503-515
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Tidskriftsartikel (refereegranskat)abstract
- The initial atmospheric corrosion of ZM (ZnAlMg)-coated steel in humid air (85% RH) and humid argon (85% RH) containing 320 ppb SO2 was studied using in situ infrared reflection absorption spectroscopy (IRRAS), FTIR-ATR focal plane array (FPA) imaging and SEM-EDS. The corrosion products formed in humid air containing SO2 are mainly composed of magnesium sulphites and sulphates, with sulphite-containing corrosion products formed initially while the contribution from sulphates increased with exposure time. The results from FTIR-FPA imaging and SEM-EDS showed that the magnesium sulphite and sulphate are formed mainly on eutectic phases with a higher quantity of corrosion products formed on the binary eutectic (Zn-MgZn2 ) phases. This is due to presence of microgalvanic elements with the zinc-rich phases as the main sites for the cathodic oxygen reduction while the anodic reactions take place on the eutectic areas. Sulphate content is the highest on the binary eutectic phases, due to the microgalvanic effects and the production of oxidants by the cathodic reaction, which increases the oxidation of sulphite to sulphate.
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| 18. |
- Sjögren, Lena, et al.
(författare)
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On-line corrosion monitoring of indoor atmospheres
- 2004
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Ingår i: EUROCORR 2004 - European Corrosion Conference.
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Konferensbidrag (refereegranskat)abstract
- For indoor conditions, risks of corrosion are more easily and more reliably estimated by exposing reference metals, as compared to by analysing climatic conditions and air pollutants. Corrosion of the reference metals can be evaluated as metal loss or metal gain, by electrolytic reduction or by methods permitting more or less continuous corrosion monitoring. Sensitive and continuous monitoring methods would be useful for classifying conditions in permanent or temporary museum displays, for selecting between storage facilities for corrosion sensitive artefacts, for evaluating effects of visitors or effects of air conditioning etc. Commercially available instruments for on-line corrosion monitoring of atmospheres indoors, the quartz crystal microbalance and electrical resistance sensors, have been evaluated for sensitivity, reliability and fitness for use. Additionally, performance of laboratory manufactured electrical resistance sensors is evaluated. These sensors are to be used with a small battery operated corrosion logger currently under development. The corrosion logger is intended for permanent or temporary use, such as in display cases, in cabinets intended for storage of sensitive objects or even in transport packages. A quartz crystal microbalance measures the resonance frequency of a metal-coated quartz crystal. Corrosion of the metal coating leads to the formation of a corrosion film on the surface, increasing the weight of the crystal, decreasing its resonance frequency. Drawbacks of the method are that the readings are slightly temperature dependent and affected by particles and other contaminants on the surface, as well as by moisture films, thus by the relative humidity. With electrical resistance sensors, corrosion is measured as changes in resistance of a thin metal track. The resistance increases when the metal thickness is reduced from corrosion. Since this method measures corrosion directly it is not affected by particles or by the humidity. Common for both methods is that only metals attacked by uniform corrosion are suitable, not metals susceptible to local corrosion such as pitting corrosion. In this investigation, copper and silver coatings have been employed. For both methods the sensitivity was found to be sufficient for monitoring atmospheric conditions in rooms requiring low corrosion rates, such as instrument rooms and museums. Electrical resistance sensors seem to be the sensor type best suited for use under indoors atmospheric conditions. Further development, optimizing sensitivity and variation in response for use with the corrosion logger under development, is needed as well as expanding the range of metals used.
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| 19. |
- Sjögren, Lena, et al.
(författare)
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On-line corrosion monitoring of indoor atmospheres
- 2007
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Ingår i: Corrosion of Metallic Heritage Artefacts: Investigation, Conservation and Prediction of Long Term Behaviour. - : Elsevier Inc.. - 9781845692391 ; , s. 293-307
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 20. |
- Thierry, Dominique, et al.
(författare)
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Basic considerations for the development of a corrosion test for stainless steels used for automotive applications
- 2004
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Ingår i: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the corrosion performance of stainless steel materials for application in the automotive industry has been evaluated by means of on-vehicle testing and laboratory cyclic corrosion tests. Additional laboratory measurements have also been performed in well defined exposure conditions. The results indicate that no cosmetic corrosion was observed upon on-vehicle exposures after 2 years exposure in Sweden and Germany and 5 years exposure in France. Cyclic corrosion tests were also performed in order to assess the corrosion resistance of different stainless steel grades. The results indicate large discrepancies in corrosion resistance when comparing the different cycles. This is explained by differences in chloride deposition, wet/dry cycle condition and way of deposition of the pollution on the samples. From the results it is obvious that cyclic accelerated corrosion tests that have been developed for assessing the performance of precoated materials cannot directly be used to assess the corrosion resistance of stainless steel. Hence, there is a need to develop or to adapt cyclic corrosion tests in order to evaluate the corrosion resistance of stainless steel. Copyright © 2004 SAE International.
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| 21. |
- Thierry, Dominique, et al.
(författare)
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Corrosion of hot-dip-galvanised steel and zinc alloy-coated steel in ammonia and ammonium chloride
- 2020
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Ingår i: Materials and corrosion - Werkstoffe und Korrosion. - : Wiley-VCH Verlag. - 0947-5117 .- 1521-4176. ; 71:7, s. 1118-1124
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Tidskriftsartikel (refereegranskat)abstract
- There are many potential causes of corrosion in animal buildings. Animals exhale large quantities of moisture into the air creating high relative humidity in the building if the moisture is not properly vented. High humidity increases the potential for condensation. In addition, ammonia may be found in large quantities in animal buildings. Ammonia is released from manure and urine. In addition, ammonium chloride is used as a nitrogen source in fertilisers. In this study, the atmospheric corrosion of hot-dip-galvanised steel and zinc alloy-coated steel such as zinc–aluminium and zinc–aluminium–magnesium has been studied in atmospheres containing different levels of ammonia. Investigations have also been conducted at different levels of ammonium chloride. The results are discussed in view of the mechanisms of corrosion of zinc and zinc alloy-coated steel in ammonia and ammonium chloride-containing environments.
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| 22. |
- Thierry, Dominique, et al.
(författare)
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Long-term atmospheric corrosion rates of Zn55Al-coated steel
- 2024
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Ingår i: Materials and corrosion - Werkstoffe und Korrosion. - : John Wiley and Sons Inc. - 0947-5117 .- 1521-4176.
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Tidskriftsartikel (refereegranskat)abstract
- Hot-dip Zn55Al-coated steel samples have been exposed for up to 6 years at 11 different weathering sites, including marine, marine-industrial, acid-rain and dry atmospheres. From the mass loss measurements, Zn55Al metallic coating showed globally long-term good corrosion resistance in all weathering conditions compared with hot-dip Zn-0.2Al-coated steel (Z). Yet, weaker performance was observed on Zn55Al in high SO2 polluted atmosphere, particularly when combined with seawater aerosols. This is explained by a more acidic surface condition linked to high SO2. Although the extent of corrosion in this phase was different at the different sites, the final corrosion products formed after 6 years were rather similar at all sites. This consists of hydrous aluminium sulphate or hydrous aluminium hydroxy sulphate and, probably also a smaller amount of sulphate-containing zinc corrosion products or Al/Zn products.
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