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US 2003/0148870 A1Published application
Silicon nitride sintered material and process for production thereof
AssigneeNGK Insulators, Ltd.
InventorsKiyoshi Araki, Tsuneaki Ohashi, Katsuhiro Inoue, Masaaki Masuda
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Abstract
A silicon nitride sintered material includes a polycrystal material having silicon nitride crystal grains and a grain boundary phase. The sintered material contains a Yb element in an amount of 2 to 30% by weight in terms of its oxide and an Al element 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 1×105 to 1×1012 Ω·cm at room temperature, and a porosity of 0.5% or less.
Claims3
A process for producing a silicon nitride sintered body, comprising:
- preparing a raw material comprising silicon nitride powder, at least 10 parts by weight of which is β-silicon nitride, 10 to 30 wt % Yb in the form of an oxide, and 1 to 20 wt % Al in the form of an oxide;
- molding the raw material to form a molded body;
- and
- firing the molded body in a non-oxidizing atmosphere at no more than 1,850° C., wherein said silicon nitride sintered body has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1×105 to 1×1012 Ω.cm at room temperature, and a porosity of 0.5% or less.
1 more element
Dependencies are inferred from the claim text.