The effect of surface roughness on corrosion resistance of machined and epoxy coated steel
| Autor: | Asbjørn Hognestad, Knut Sørby, Ole Øystein Knudsen, Catalina Hoem Musinoi Hagen |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
General Chemical Engineering Organic Chemistry Delamination 02 engineering and technology Epoxy Surface finish engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Corrosion Machining Coating visual_art Materials Chemistry engineering Surface roughness visual_art.visual_art_medium Composite material 0210 nano-technology Contact area |
| Popis: | By incorporating periodic micro-patterns on steel substrates, the effect of surface roughness on corrosion resistance of a two-component polyamine cured epoxy mastic coating has been studied. Machining was employed to pattern the surfaces with periodic peaks of varying peak-to-valley heights, Rz. The focus of the study was to find the surface parameter that contributes most to the stability of an organic coating in corrosive environment, and to evaluate if machining can be comparable to blast cleaning with respect to coating durability. A strong correlation between roughness (Rz) and corrosive delamination of coated surfaces was seen. Increasing Rz from 57 μm to 252 μm on surfaces with triangular peaks, increased the effective contact area by 40% and decreased delamination by 30%. By introducing tilted asperities at Rz = 224 μm while keeping the effective contact area in general unchanged, delamination decreased another 55%. Hence, an increased Rz is found to be only partially beneficial, and the profile shape is more significant than the roughness value per se. The results suggest that mechanical interlocking has a substantial influence on the interfacial stability of protective coatings in corrosive environments. By optimal selection of cutting parameters, machining can give surfaces where protective coatings have long lifetime. |
| Databáze: | OpenAIRE |
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