激光诱导气相合成Si_3N_4/SiC纳米粉试验工艺研究

A Technic Study of the Laser Synthesis of Si_3N_4/SiC Nanopowders from Hexamethyldisilazane

选择廉价的六甲基乙硅胺烷((Me_3Si)_2NH)和氨气为原料,采用正交设计试验参数的方法,研究了激光功率密度、六甲基乙硅胺烷蒸汽流量、氨气流量对粉体化学组成的影响。制备出低游高碳含量,高Si_3N_4含量的Si_3N_4/SiC粉体。研究结果表明,在选定的试验参数范围内,形成的粉体中Si_3N_4、SiC的相对含量在较大的范围内变化。对Si_3N_4粉体中Si_3N_4的形成影响最大的是激光功率密度,六甲基乙硅胺烷流量对其影响最小。通过试验得到了高Si_3N_4含量,低游离碳含量的Si_3N_4/SiC纳米粉形成的最佳工艺参数。

Organic silane hexamethyldisilazane and ammonia were used as the reactants to produce Si_3N_4/SiC nanopowders. The influences of laser power, hexamethyldisilazane vapor flow rate, and ammonia flow rate on the chemical compositions of the powders have been studied by the orthogonal design of the processing parameters. The powers with low free carbon content and high silicon nitride content have been successfully synthesized. The results show that the contents of silicon nitride and silicon carbide in the powders change largely based upon the processing parameters. Laser power density has the greatest influence on the formation of silicon nitride in the powders, while the flow rate of hexamethyldisilazane has the smallest influence. The optimum processing parameters favourable of the formation of Si_3N_4/SiC powders with high silicon nitride content and low free carbon content have been obtained.