Influence of Substrate Surface Roughness on Adhesive Property of Sprayed Coating

Abstract

Abstract Though the adhesion between substrate and sprayed coating seems to be mainly due to the anchoring effect, quantitative examinations have not been sufficient. In this paper, the surface condition of a roughened substrate is quantitatively evaluated using a surface roughness tester, and the adhesive relationship is clarified. Substrate used was S45C(JIS standard) carbon steel, and the roughening methods were blasting and endless belt polishing with alumina grit, in various roughening conditions. A pure copper coating was formed using the powder flame spraying method on roughened substrate. The drawing adhesion strength test method was used to evaluate the adhesive properties. The adhesive strength is reduced, though the surface roughness of the substrate increases, as the size of the grid particles for roughening increase. The alumina grits remained on the substrate after roughening, and they were removed by ultrasonic cleaning. Though there is no relation between the adhesive strength and the ratio of the increase in the surface area of substrate due to the roughening treatment, it is recognized that the adhesive strength also increases when the roughness gradient of the substrate increases.