原位合成NiO催化硅粉氮化制备氮化硅

Silicon Nitride Preparation via Nitridation of Silicon Powder Catalyzed with In Situ Synthesized NiO

采用化学沉淀方法在硅粉表面沉淀了Ni（OH）2,利用其原位合成NiO来催化硅粉氮化制备Si3N4粉,研究了原位合成NiO含量（质量分数为0-2.0%）和氮化温度对硅粉氮化的影响。结果表明：原位合成的NiO可以促进硅粉的氮化,随着NiO含量的增加,硅粉的氮化率呈先增后减的变化趋势;随着氮化温度的升高,硅粉氮化率逐渐提高,当温度升高到1 400℃、NiO质量分数为1.0%时硅粉全部氮化;制备的Si3N4呈晶须状,直径为65~497nm,其生长符合固-液-气-固（SLGS）生长机理。

The Ni（OH）2was precipitated on the silicon powder surface by chemical precipitation method,and then the in situ synthesized NiO was used to catalyze the nitridation of silicon powder to prepare the Si3N4 powder.The effects of in situ synthesized NiO content（0-2.0wt%）and nitridation temperature on the nitridation of silicon powder were studied.The results show that the in situ synthesized NiO improved the nitridation of silicon powder.With the increase of NiO content,the nitridation rate of silicon powder first increased then decreased.With the increase of nitridation temperature,the nitridation rate of silicon powder increased gradually.The silicon powder with NiO content of 1.0wt% was nitrided completely at the temperature of 1 400℃.The prepared Si3N4 showed a whisker-like shape with diameters of 65-497 nm and its growth accorded with the solid-liquid-gas-solid（SLGS）growth mechanism.