Electrochemical behaviour of thermally sprayed Cr3C2-NiCr coatings in 0.5 M H2SO4 media
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Data
2002-11-01
Autores
Suegama, P. H.
Fugivara, Cecilio Sadao [UNESP]
Benedetti, Assis Vicente [UNESP]
Fernandez, J.
Delgado, J.
Guilemany, J. M.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Kluwer Academic Publ
Resumo
The electrochemical behaviour of coated Cr3C2-NiCr steel in aerated 0.5 M H2SO4 solution was studied by means of electrochemical a.c. and d.c. measurements. A complete structural characterization of the coated steel before and after electrochemical tests was also carried out to access the corrosion mechanism of coated steel, electrolyte penetration through the coating, and to confirm the results obtained using electrochemical techniques. Two types of Cr3C2-NiCr coatings produced by a high velocity oxy-fuel spraying system (HVOF) were studied. Differences between coated steels are related to the spraying parameters reflecting their behaviour against corrosion phenomena. The electrochemical behaviour of the coated steel was strongly influenced by porosity and the presence of microcracks in the coating. Once the electrolyte reaches the steel substrate, it corrodes in a galvanic manner resulting in coating detachment from the steel.
Descrição
Palavras-chave
corrosion, Cr3C2-NiCr coating, electrochemical techniques, HVOF, steel protection, thermal spraying
Como citar
Journal of Applied Electrochemistry. Dordrecht: Kluwer Academic Publ, v. 32, n. 11, p. 1287-1295, 2002.