| 摘要 |
PROBLEM TO BE SOLVED: To produce a silicon nitride sintered compact having a high heat conductivity and superior heat radiating property as well as high strength characteristics peculiar to the silicon nitride sintered compact. SOLUTION: The silicon nitride sintered compact contains >7.5 to 17.5 wt.% (expressed in terms of oxides) at least two rare earth elements, optionally contains <=1.0 wt.% at least one of aluminum nitride and alumina and 0.1-3.0 wt.% at least one selected from the group consisting of oxides, carbides, nitrides, silicides and borides of Ti, Zr, Hf, V Nb, Ta, Cr, Mo and W and contains <=0.3 wt.%, in total, of Li, Na, K, Fe, Ca, Mg, Sr, Ba, Mn and B as other cationic impurity elements. The sintered compact consists of β-phase silicon carbidde crystal and a grain boundary phase. The proportion of a crystalline compd. phase in the grain boundary phase to the entire grain boundary phase is >=20%. The sintered compact has <=2.5 vol.% porosity, >=80 W/m.K heat conductivity and >=650 MPa three-point bending strength at room temp. |
