プラズマ溶射によるセラミック被覆材の耐食性評価

概要

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To make clear the performance of plasma-sprayed ceramic coating, several investigations concerning degradation characteristics including tribological and adhesive strength are being conducted these days. In this paper, corrosion characteristics of plasma-sprayed ceramic coating, which is used for various applications as thermal barrier and antierosive coatings, were evaluated from electro-chemical view points. As a result, it was recognized that the zirconia top coat layer contained a lot of pores and cracks. The corrosion damage of plasma-sprayed ceramic coating was brought about by the anodic dissolution of under coat NiCrAlY layer at the boundary between the zirconia top coat and the under coated layer. Various electrochemical examinations about the corrosion characters of plasma-sprayed ceramic coating indicated the folowing facts. Under freely corroding conditions, plasma-sprayed ceramic coating has little contribution to improve the corrosion characteristics of matrix metals, especially in 3% NaCl aquerous solution. Therefore, for evaluating the corrosion resistance of plasma-sprayed ceramic coating, the anodic dissolution by corrosive media, which come into the boundary layer through open voids in the top coat ceramic layer, is extremely important.
社団法人日本材料学会の論文
1992-06-15