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本文述及高频等离子法制取超细Si_3N_4粉末的原理、装置,工艺参数及粉末性能的一些检测结果。利用SiCl_4+NH_3气-气相反应,所得白色粉末含有NH_4Cl晶体,热重分析表明350℃失重停止,280℃失重速率最快,经400～700℃处理后的粉末仍为非晶,不含NH_4Cl,BET测得比表面积为75.8 m~2/g,X光小角度散射法测粒子半径分布主峰R为100～150,且符合正态对数分布规律,平均直径=527;1400℃处理后,X光衍射测得主相为α-Si_3N_4、次相为Si_2N_2O,粒径明显长大,平均直径达1700。
This paper describes some of the principles, devices, process parameters and powder properties of ultrafine Si_3N_4 powder prepared by high-frequency plasma method. The obtained white powder contains NH 4 Cl crystal by SiCl 4 + NH 3 gas-gas phase reaction. The thermogravimetric analysis shows that the weight loss is stopped at 350 ℃ and the weight loss rate at 280 ℃ is the fastest. After 400 ~ 700 ℃, the powder is still amorphous and NH 4 Cl, The BET specific surface area was 75.8 m 2 / g. The X-ray small-angle scattering method measured the peak R of the particle radius distribution as 100-150 and the logarithm of the normal logarithm distribution with the average diameter of 527. After 1400 ℃ treatment, X The main phase measured by light diffraction was α-Si_3N_4 and the secondary phase was Si_2N_2O. The particle size obviously grew up with an average diameter of 1,700.