Fundamental study on mirror polishing of flat surface of ceramics with tribochemical reaction

Abstract

In pin-on-disk type wear test of silicon nitride ceramics sliding against themselves in water, mirror surfaces were frequently observed under specific sliding condition. On the basis of above results, if flat specimens of silicon nitride slide against themselves in water, it can be considered that we can obtain completely flat and mirror surface without any abrasives and polishing pad. That possibility were elucidated with a flat-on-flat type polishing equipment in this study. Surface roughness of silicon nitride flat specimen that initial surface roughness was 860nmRz decreased with sliding distance and reached to 100 nmRz. A pH value of water increased with sliding distance drastically at initial, decreased gradually with sliding distance and to reached to specific values. On the basis of the analysis of the variation of pH values and polishing amount, the process of tribochemical reaction is considered as the governing process for obtaining flat and mirror surface of silicon nitride.