Yoshihito Kondo

Grindability of silicon nitride ceramics

A hot pressed silicon nitride ceramic is very difficult to grind and it is expected to be widely applied to the heavy duty use, which does not permit the slightest machining damage. Therefore, the efficient grinding without machining damage is very necessary. In this study, the said ceramic was ground by several diamond grinding wheels in order to find out the relation between material removal rate and machining damage. According to the test results, the efficient grinding was performed using a vitrified diamond wheel of 170/200 grain size and the damaged layer was removed using a resinoid diamond grinding wheel of 270/325. [Received August 1, 1985]

Ground Surface of Y-TZP

A monoclinic phase is frequently seen on fractured surfaces of yttria stabilized tetragonal ZrO2 polycrystals (Y-TZP). In this study, Y-TZP materials were ground by diamond grinding wheels of different grain sizes and the effects of grinding on the structure in the surface layers was examined from the viewpoint of the grinding mechanism. It was found that a compressive layer was formed on the ground surface and bending strength was increased by grinding under specific conditions.