COMPOSITE SINTER OF SILICON NITRIDE/BORON NITRIDE AND METHOD FOR MANUFACTURING THEREOF

摘要

A composite sinter of silicon nitride/boron nitride, which consists essentially of, in weight percentage, silicon nitride within the range of from 60 to 97% and boron nitride within the range of from 3 to 40% and wherein said boron nitride is present as a dispersed phase in the network of said silicon nitride; said composite sinter of silicon nitride/boron nitride being manufactured by the steps of: kneading a silicon powder within the range of from 47.3 to 95.1 wt.% and a boron nitride powder within the range of from 4.9 to 52.7 wt.% as raw materials, with the use cf an organic solvent solution containing a dispersant and a binder; press-forming the resultant kneaded mixture to prepare a green compact; sintering said green compact in a nonoxidizing atmosphere at a temperature within the range of from 1,100 to 1,300.degree.C to prepare a sinter having a strength permitting machining; machining said sinter into prescribed dimensions; and sintering again the resultant machined sinter in a nitrogen atmosphere at a temperature within the range of from 1,250 to 1,450.degree.C to nitrify the same, thereby improving strength and thermal shock resistance of said sinter.