Influence of surface roughness on the anticorrosion performance of plasma sprayed amorphous coating and its electrochemical evaluation

Abstract

In this current survey, the association relating surface roughness to electrochemical corrosion capability of plasma sprayed Fe48Cr15Mo14C15B6Y2 amorphous coating was examined. The impact of semiconducting performance, compositional variation and point defects diffusivity on the electrochemical anti-corrosion behavior was also evaluated. In case of chloride-containing electrolyte, a rougher surface of the coating degraded the passivity and anti-corrosion capacity of passive film. The increase of hydroxyl vacancies contributed to a more defective passive film accompanied by a greater donor density for the coating with a rougher surface. Moreover, a reduction in Mo elemental species was not conductive to a continual growth of insoluble oxide Cr2O3, which was found as the dominant factor decreasing the resistance to corrosion of the generated film. A higher diffusivity of point defects existent in the generated layer owing to a rougher surface led to a more rapid mass transfer process.