| 摘要 |
PROBLEM TO BE SOLVED: To provide a silicon nitride powder for a mold-releasing agent, which has an improved adhesive force to the inner wall of a melting crucible and thereby, can reduce the contamination of impurities and improve yield when a polycrystalline silicon ingot is manufactured.SOLUTION: The silicon nitride powder for a mold-releasing agent has a 90% particle diameter by a laser diffraction scattering method of 3.0-10 μm, a ratio of α-phase of 20-60%, and an iron content of 100 ppm or less, and is characterized in that the particle size distribution has two maximum values; one maximum value is in the range of 0.2 μm or more and less than 1.0 μm (maximum value 1) and another maximum value is in the range of 1.0-8.0 μm (maximum value 2); the ratio of the frequency of the maximum value 2 to the frequency of the maximum value 1 {(frequency of maximum value 2)/(frequency of maximum value 1)} is 1.0-5.0, and the interval between the maximum values 1 and 2 is 0.8-7.8 μm. |
