Study on concentric mutual lapping for improvement in sliding surface function of SiC ceramics

In this study, the ring shaped SiC ceramics applied to sliding components are selected as specimens. In the surface of SiC ceramics, many scratches penetrating the inner edge to outer one are generated in random direction by conventional lapping. The scratches affect the surface functions in prevention of fluid exuding from the outer side to the inner side of SiC ring and have low friction force on the finished surface as a sliding material. In this study, the concentric mutual lapping is proposed to remove the scratches by conventional lapping. Then, the surface topography is evaluated quantitatively by the white light interferometer and proposed the vectorial and quantitative analysis of surface profile. As a result, the concentric mutual lapping can remove scratches quickly by the conventional lapping. And then circumferential scratches along a lapping direction were generated. In addition, we analyzed effect of surface topography on the surface function as a sliding material by sliding tests. From the investigation, it turned out that the concentric mutual lapping suppressed the difference in surface functions depending on the sliding direction.