| 摘要 |
PURPOSE: To obtain a silicon nitride sintered compact free from pores and residual silicon as defects in a silicon nitride sintered compact using silicon as stock, having a dense structure and excellent in mechanical strength by heating a compact using silicon stock contg. much Fe as an impurity and having a specified compsn. in an N2 -contg. atmosphere. CONSTITUTION: This silicon nitride sintered compact contains 0.005-15wt.% Fe and Fe-contg. compd. particles of >=0.2μm particle diameter contained in this sintered compact account for 0.1-12 area % of a two-dimensional range of 200×200μm. This silicon nitride sintered compact is produced as follows: a compact having a compsn. satisfying the formulae is formed using materials contg. at least Si, Al, Y, O, N and Fe as elements and this compact is heated at about 1,200-1,500 deg.C in an atmosphere of nitrogen-contg. gas and is then reheated at 1,700-2,000 deg.C. In the formulae, (a), (b), (c) and (d) are the weights of Si3 N4 , AlN, Y2 O3 and Fe as a compd. or element from the elements. |
