SILICON NITRIDE POWDER FOR SINTERING

To provide a β-type silicon nitride powder for obtaining a sintered body having high strength and high toughness.SOLUTION: A silicon nitride powder for sintering comprises a silicon nitride powder having a β formation ratio of 80% or more, in which when a volume frequency distribution curve showing the particle size distribution is subjected to waveform separation, there exist a separation waveform a having a peak within the range of 0.5 μm or more and 1 μm or less and a separation waveform b having a peak within the range of more than 1 μm and 3 μm or less, the total area of the separation waveform a and the separation waveform b is 60 to 98% based on the total area of the total separation waveform, and the ratio of the area of the separation waveform a to the area of the separation waveform b (Sa/Sb) is 0.4 to 0.8.SELECTED DRAWING: None 【課題】高強度及び高靭性の焼結体が得られるβ型の窒化ケイ素粉末を提供する。【解決手段】 β化率が８０％以上の窒化ケイ素粉末よりなり、その粒度分布を示す体積頻度分布曲線を波形分離したとき、０．５μｍ以上１μｍ以下の間にピークを有する分離波形ａ、１μｍ超３μｍ以下の間にピークを有する分離波形ｂが存在し、前記分離波形ａ及び分離波形ｂの合計面積は、全分離波形の合計面積に対して６０～９８％であり、前記分離波形ｂの面積に対する前記分離波形ａの面積の比（Ｓａ／Ｓｂ）が０．４～０．８であることを特徴とする、焼結用窒化ケイ素粉末。【選択図】なし