Ni纳米颗粒催化氮化反应制备氮化硅粉体

Catalytic Effect of Ni Nanoparticles on Nitridation of Silicon Powders

采用化学原位还原法将Ni纳米颗粒均匀负载于Si粉表面,研究了Ni纳米催化剂用量对不同温度(1 200~1400℃)时Si粉的氮化行为的影响及Si_3N_4粉体的形成及机理。结果表明:含2%(质量分数,下同)Ni纳米催化剂的样品1 350℃氮化2 h后,其中残留的Si含量仅为3%;Ni纳米催化剂的引入可以有效地促进Si_3N_4晶须的生成;密度泛函理论计算表明,Ni纳米颗粒催化剂可以促进N_2分子在较低温度下解离为N原子,进而加快了Si粉的氮化。

The effect and mechanism of Ni nanoparticles （NPs） on the nitridation of Si particles were investigated. Ni NPs were deposited homogeneously on the surfaces of Si particles by an in–situ chemical reduction method. Si particles impregnated with 0.5~2.0% Ni NPs were nitrided in 1 200~1 400 ℃ for 2 h. The results show that there are only approximately 3% unreacted Si in the sample nitrided at 1 350 ℃ for 2 h when 2% Ni NPs are used as a catalyst. Also, there are still 50% Si remained in the sample without any catalyst under the identical conditions. The massive whiskers are formed in the sample when Ni nanoparticles are used as a catalyst. Based on the DFT calculation, Ni NPs can promote the dissociation of N2 molecule and enhance the nitridation of Si at a relatively low temperature.