Wang Xuefeng， Liu Pengfei， Han Zhao， Li Jie
School of Metallurgical Engineering， Anhui University of Technology， Ma'anshan 243000
Abstract
Objective As applications of silicon nitride ceramics expand， the demand for high-quality silicon nitride powders grows. This paper focuses on controlling the morphology and particle size of silicon nitride powder to successfully prepare high-quality equiaxed silicon nitride powder for ceramics.
Methods Silicon nitride （Si3N4） powders with regular morphology were prepared using silicon imine （Si（NH）2） as the raw material through high-energy ball milling and high-temperature pyrolysis. The effects of different ball milling parameters on the morphology and particle size of Si3N4 powders were investigated. First， the Si（NH）2 powder was dry-milled in a horizontal planetary ball mill under different ball-to-powder weight ratios， milling times， and milling velocities. The ball milling process was conducted in an Ar atmosphere， using Si3N4 ceramic balls as the ball milling medium. After ball milling， the powder was sieved and encapsulated in a graphite crucible under Ar protection. Finally， the crucible was placed in a tube furnace and heated to a certain temperature at a heating rate of 5 °C/min under a flowing nitrogen atmosphere. The holding time was 2 h， and the Si3N4 powder was obtained after cooling to room temperature within the furnace.
Results and Discussion High-energy ball milling treatment significantly impacted the morphology and particle size of Si3N4 powder. After ball milling， the powder changed from small particles with irregular morphology to large hexagonal prism particles with smooth surfaces and regular morphology. As ball milling progressed， the particle size of Si3N4 powder initially decreased and then increased. When the rotation speed was 200 r/min， the ball-to-powder weight ratio （mass ratio） was 20， and the ball milling time was 2 h， α-phase Si3N4 powder with smooth surfaces， regular morphology， and an average particle size of about 823 nm was obtained. The growth process of Si3N4 powder particles was divided into two stages： nucleation and growth. After ball milling， the degree of amorphization of Si（NH）2 increased， and the mechanical force during ball milling formed trace crystalline cores in Si（NH）2. These crystalline cores， generated during the ball milling stage， provided sufficient nucleation sites for the gas phase products produced by the decomposition of amorphous Si3N4 during the pyrolysis process. This induced Si3N4 to grow along the crystalline cores， ultimately forming Si3N4 powder with equiaxed regular morphology.
Conclusion High-energy ball milling Si（NH）2 accelerates the nucleation rate of amorphous Si3N4 and provides nucleation sites， which is key to adjusting the morphology and particle size of Si3N4 powder particles. The study provides a new reference for high-end Si3N4 powder preparation and supports China’s raw material capabilities in key areas.
Keywords： silicon imide； high-energy ball milling； silicon nitride； mechanical force
Get Citation:Wang Xuefeng， Liu Pengfei， Han Zhao， et al. Preparation of equiaxed silicon nitride powders by silicon imine ball milling［J］. China Powder Science and Technology， 2026， 32（6）： 1-11.
Received: 2025-01-22, Revised: 2025-02-20, Online: 2026-05-16.
Funding:This work was supported by the National Natural Science Foundation of China (Grant No. 52074003).
DOI：10.13732/j.issn.1008-5548.2026.06.004
CLC No.：TQ170；TB44
Type Code：A
Serial No.：1008-5548（2026）06-0001-11
