Patent ID: 10399854

Abstract:
A silicon nitride powder having a specific surface area of 4.0 to 9.0 m2/g, a β phase proportion of less than 40 mass %, and an oxygen content of 0.20 to 0.95 mass %, wherein a frequency distribution curve obtained by measuring a volume-based particle size distribution by a laser diffraction scattering method has two peaks, peak tops of the peaks are present respectively at 0.4 to 0.7 μm and 1.5 to 3.0 μm, a ratio of frequencies of the peak tops ((frequency of the peak top in a particle diameter range of 0.4 to 0.7 μm)/(frequency of the peak top in a particle diameter range of 1.5 to 3.0 μm)) is 0.5 to 1.5, and a ratio D50/DBET (μm/μm) of a median diameter D50 (μm) determined by the measurement of particle size distribution to a specific surface area-equivalent diameter DBET (μm) calculated from the specific surface area is 3.5 or more.