| 摘要 |
PROBLEM TO BE SOLVED: To obtain a silicon nitride-base sintered compact having a high coefft. of thermal expansion and excellent thermal shock resistance by incorporating silicon nitride, a rare earth element compd., a Cr compd. and silicon carbide having a specified average particle diameter and imparting a specified coefft. of thermal expansion in the case of heating to a specified temp. SOLUTION: The sintered compact contains silicon nitride, a compd. of a rare earth element such as Y, La or Sc, a Cr compd. selected from oxide, carbide, nitride, silicide, etc., of Cr and 5-20 pts.wt. silicon carbide having 3-10 μm average particle diameter based on 100 pts.wt. of the sintered compact and has >=3.5×10-6/Kcoefft. of thermal expansion in the case of heating from 30 deg.C to 1,350 deg.C. The sintered compact is obtd. by mixing silicon nitride, the rare earth element compd., the Cr compd. and silicon carbide particles in a prescribed ratio and firing the mixture at 1,700-1,800 deg.C and >=20 MPa for 15-60 min. The coefft. of thermal expansion is calculated from the formula-[(the standard length of a sample at 1,350 deg.C)-(the measured length of the sample at 1,350 deg.C)/[(the measured length of the sample at 30 deg.C)×(1,350-30)]+8.45×10-6/K. |
