METHOD FOR INCREASING TOUGHNESS OF SILICON NITRIDE SINTERED COMPACT

摘要

PROBLEM TO BE SOLVED: To increase the toughness of a silicon nitride sintered compact. SOLUTION: A silicon nitride compact contg. a sintering aid is sintered by microwave heating at 1,600-1,900 deg.C for 30min to 6hr in an atmosphere of nitrogen to produce silicon nitride ceramics having >=6MPa.m<1/2> fracture toughness. Such silicon nitride ceramics as a preliminarily sintered compact contg. a sintering and produced by the same sintering method of the silicon nitride compact as usual is heat-treated by microwave heating at 1,600-1,900 deg.C for 1-24hr in an atmosphere of nitrogen to increase the fracture toughness of the ceramics to >=7MPa.m<1/2> .