| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high strength and high hardness sintered compact excellent in reliability by incorporating specified amts. of Mg and Yb compds. into silicon nitride or sialon as a base and carrying out sintering. SOLUTION: Silicon nitride or sialon is mixed with 0.5-3wt.% (expressed in terms of Mg) Mg compd. and 3-10wt.% (expressed in terms of Yb2 O3 ) Yb compd. and the resultant mixture is compacted and fired at 1,300-1,550 deg.C to obtain the objective silicon nitride-base sintered compact. In this sintered compact, acicular silicon nitride or sialon grains each having 0.01-0.3μm minor axis size and an aspect ratio of >=15 account for 20-50vol.% of all grains, one or more among Yb2 Si3 N4 O3 , Yb2 Si3 N2 O5 and Yb4 Si2 N2 O7 are contained as a crystal phase and the ratio in X-ray diffraction intensity between the crystal phase and silicon nitride or sialon is 5:10,000 to 1:10. |
