| 摘要 |
PURPOSE:A substance containing Si and N, resulting from reaction, e.g., between silicon halide and ammonia is heat-treated to form crystalline Si3N4, which is crushed and treated with hydrogen halide to produce high-purity fine particles of Si3N4 with less impurities. CONSTITUTION:Gas-phase reaction at room temperature to 1,500 deg.C or liquid- phase reaction at -100-+200 deg.C between silicon halide such as SiCl4 and ammonia and/or a mixture of N2 and H2 gases is effected to form an amorphous substance containing Si and N. Then the substance is treated at the above-cited temperature, preferably 1,000-1,700 deg.C in a nonoxidative atmosphere of N2, H2 or NH3 to form Si3N4 containing a large amount of needle crystals. The resultant Si3N4 is crushed by physical means such as steel ball mill into a powder, preferably of less than 1mu particle sizes, then the particles are treated with hydrogen halide or hydrochloric acid such as HF to give fine particles of high- purity Si3N4.
|
