| 摘要 |
A high thermal conductive silicon nitride sintered body of this invention is characterized by containing more than 7.5 wt% to at most 17.5 wt% of a rare earth element in terms of the amount of an oxide thereof, if necessary, at most 1.0 wt% of at least one of aluminum nitride and alumina, if necessary, 0.1-3.0 wt% of at least one compound selected from the group consisting of oxides, carbides, nitrides, silicides and borides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and at most 0.3 wt% of Li, Na, K, Fe, Ca, Mg, Sr, Ba, Mn and B as impurity cationic elements in terms of total amount thereof, containing a beta -type silicon nitride crystal and a grain boundary phase. The sintered body has a ratio of a crystal compound phase in the grain boundary phase to the entire grain boundary phase of at least 20%, a porosity of at most 2.5% by volume, a thermal conductivity of at least 80 W/m . K and a three-point bending strength of at least 650 MPa at a room temperature. According to the above arrangement, a silicon nitride sintered body having, in addition to the high strength characteristics generally inherent in silicon nitride sintered body, high thermal conductivity and good heat-radiating characteristics can be obtained. A press-contacted body according to the present invention is constituted such that a heat-generating part is press-contacted to a heat-radiating plate consisting of the silicon nitride sintered body. <IMAGE> |
