Patent ID: 6617272
Filing Date: 2003-09-09
Classification: C04B

Abstract:
A Si3N4 sintered body produced by reactive sintering of silicon, said Si3N4 sintered body comprising crystal grains of Si3N4 and a grain boundary phase, wherein:an oxide (Ln2O3) of at least one element (Ln) selected from the group consisting of Y, Yb and Sm is contained in an amount of 0.6 to 13% by weight; an oxygen content in the crystal grains of Si3N4 is not more than 1% by weight; a molar ratio of SiO2/Ln2O3 in the Si3N4 sintered body is within a range of 0.1 to 0.8; and the Si3N4 sintered body has a relative density in the range of 85 to 99.99%, a thermal conductivity of at least 70W/m.K or more, and a three point bending strength of at least 600 MPa.