| 摘要 |
PURPOSE:To produce a silicon nitride-based sintered body having excellent mechanical strength with advantages on productivity and cost. CONSTITUTION:A green compact having a compsn. consisting of Si3N4, a first auxiliary (Y2O3+MgO) and a second auxiliary (Al2O3 and/or AlN) within the range defined by points A, B, C, D (mol%) in the diagram is subjected to primary sintering to >=96% relative density at 1,300-1,650 deg.C in gaseous N2 under <=1.1atm. so that both alpha-and betaSi3N4 are contained. The resulting sintered body is further subjected to secondary sintering to >=99% relative density at 1,300-1,650 deg.C in gaseous N2 under >=10atm. |
