提供了适用于动力装置的热保护结构等的具有高导热性的反应烧结氮化硅的制造方法。 反应烧结氮化硅的制造方法包括以下步骤：将包括Si粉末的原料粉末研磨成具有小于或等于1微米的尺寸; 混合前一步骤研磨的Si粉末和烧结并形成其混合物的制剂; 在1350〜1450℃下对成形体进行氮化处理，在成形体内形成反应结合氮化硅; 并通过在大于或等于1850℃的温度下烧结反应结合的氮化硅来制造反应烧结的氮化硅烧结体。 根据本发明，反应烧结氮化硅烧结体具有高导热性。

The manufacturing method of reaction sintering silicon nitride sintered body and suitable for use in the heat radiation structure such as a power device having a thermal conductivity is provided. The present invention includes the steps of: milling a raw material powder containing a Si powder with a size of 1 micron or less; Mixing, and molding the milled Si powder and sintering aid; A step of nitriding the molded body at 1350 ~ 1450 ^o C to form a reaction bonded silicon nitride, in the formed article; And it provides a method for producing sintered silicon nitride reaction-sintered body comprising the step of producing a reaction sintered silicon nitride sintered body by sintering after the reaction bonded silicon nitride at least 1850 ^o C temperature. According to the invention, it is possible to provide a reaction sintered silicon nitride sintered body of high thermal conductivity.