Patent ID: 6541406
Filing Date: 2003-04-01
Classification: C04B

Abstract:
A silicon nitride sintered material comprising a polycrystal material having silicon nitride crystal grains and a grain boundary phase,which sintered material contains Yb in an amount of 10 to 30% by weight in terms of its oxide and Al in an amount of 1 to 20% by weight in terms of its oxide and has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1Ã—105 to 1Ã—1012 &OHgr;Â·cm at room temperature, and a porosity of 0.5% or less, wherein a starting material for said silicon nitride sintered material comprises at least 10 wt % &bgr;-silicon nitride.