| 摘要 |
PROBLEM TO BE SOLVED: To produce a silicon nitride sintered compact having sufficient mechanical characteristics and thermal conductivity as a circuit substrate and capable of preventing malfunction of a semiconductor element with electromagnetic waves, etc., and to provide a method for producing the silicon nitride sintered compact. SOLUTION: This silicon nitride sintered compact comprises silicon nitride crystal grains, microcrystal grains comprising a metal simple substance and/or a compound of at least one kind of element selected from W and Mo and a grain boundary phase. The microcrystal grains are dispersed in the sintered compact. Further, the sintered compact is produced by including a rare earth element in an amount of 1.0-10 wt.% expressed in terms of an oxide, Mg in an amount of 0.3-5 wt.% expressed in terms of an oxide and W and/or Mo in an amount of 0.001-5.0 wt.% expressed in terms of a carbide and making >=5 silicon nitride grains having >=30 μm major axis length exist in an optional region of 200×150 μm size in the sintered compact. |
