Investigation of selected HVOF and plasma sprayed coatings for sustained performance in molten zinc
[Display omitted] •Long term degradation behaviour of carbide and oxide based thermal spray coatings in molten zinc is studied.•WC-Co coating degradation mechanism is the dissolution of cobalt in molten zinc followed by carbide detachment.•Al2O3-TiO2 coating shows formation of unwanted spinel (zinc...
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Veröffentlicht in: | Corrosion science 2021-03, Vol.180, p.109177, Article 109177 |
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Format: | Artikel |
Sprache: | eng |
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•Long term degradation behaviour of carbide and oxide based thermal spray coatings in molten zinc is studied.•WC-Co coating degradation mechanism is the dissolution of cobalt in molten zinc followed by carbide detachment.•Al2O3-TiO2 coating shows formation of unwanted spinel (zinc titanate) during prolonged exposure in molten zinc.•After 30 days exposure in molten zinc, Al2O3 coating remains completely inert and maintains complete coating integrity.
Thermal spray coatings, especially WC-12Co, applied on galvanizing line hardware exhibit enhanced corrosion resistance in molten zinc environment. However, the service life of such coated components is usually reported up to 15 days. This work studies 30 days of prolonged performance for coatings like Cr3C2-NiCr, Al2O3, Al2O3-TiO2 and WC-12Co in molten zinc. Post-testing, stability of the coatings was assessed by corrosion products and phase analysis along with elemental mapping, surface morphology and porosity across top and cross sections and weight change data. Property evaluation of these coatings indicates better performance of oxide coatings, particularly Al2O3, as compared to carbide coatings. |
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ISSN: | 0010-938X 1879-0496 |
DOI: | 10.1016/j.corsci.2020.109177 |