Silicon nitride bodies and a process for producing the same.

摘要

A silicon nitride body wherein a number of grain boundaries of Si3N4 per a length of 10 mu m is not more than 20 when measured along a straight line drawn in an arbitrary section of the silicon nitride body. A process is disclosed for producing such a silicon nitride body, which comprises the steps of grinding and mixing a raw material of silicon nitride and not more than 0.3 wt% of A l when calculated as A l 2O3, shaping the mixture, and firing the shaped body. The silicon nitride bodies may be not only silicon nitride sintered bodies, but also vapor deposited films of silicon nitride formed by CVD or the like, frame sprayed films of silicon nitride formed by flame spraying, etc. These silicon nitride bodies have an advantageously high thermal conductivity.