Gas pressure sintering of silicon nitride with addition of rare earth oxides

摘要

A silicon nitride base sintered body having high strength at normal and high temperatures is obtained by a nitrogen gas atmosphere pressure sintering method using a combination of Y.sub.2 O.sub.3 and Nd. sub.2 O. sub.3 and/or Sm.sub.2 O.sub.3 as a sintering aid. The molar ratio of Y. sub.2 O.sub.3 to Nd.sub.2 O.sub.3 and/or Sm.sub.2 O.sub.3 is from 9:1 to 1:9. The pressure of the nitrogen gas atmosphere is not lower than 1 atm and is lower than 500 atm. The sintering temperature is 1750°-2200. degree. C.