自分散SiNWs粉体的制备及形貌表征

Preparation and microstructure characterization of self-scattered SiNWs powders

以Si粉和Ni(NO3)2·6H2O为原料,制备具有包覆结构的Si-Ni粉体,后经共晶生长析出具有自分散特征的硅纳米线(silicon nano wires,SiNWs)粉体。该粉体的成功制备有效解决了传统SiNWs易于缠绕和团聚的难题,使得SiNWs复合功能材料的制备成为可能。研究结果表明,SiNi摩尔比和Si粒径对镍包硅结构粉体、SiNWs的数量等生长动力学过程有重要的影响。采用粒径为74μm的Si粉获得的SiNWs呈线状,且当共晶反应温度为950℃,保温时间为120min,n(Si)∶n(Ni)=2∶1,获得的SiNWs分布均匀,占总体积的80%。若采用球磨法将Si粉的粒径细化至100nm,则可获得以Si核为中心呈径向不断生长的SiNWs粉体,单根直径约150 nm,长度约1.5μm,具有很好的自分散性。

Silicon and Ni(NO3)2·6H2O were used as raw materials to prepare nickel coated silicon powder,and then'self-scattered'silicon nano wires(SiNWs)were formed by interface eutectic reaction between silicon and nickel.The'self-scattered'SiNWs can be easily mixed with different materials to form composites without twining and agglomeration which are typical problems of traditional nanowires.It's indicated that both molar ratio of Si to Ni and silicon particle size have important influence on growth kinetics of SiNWs including the coating appearance and quantity of SiNWs.When the particle size of silicon was 74μm,80% of the mixture grew into linear SiNWs through annealing at 950℃for 120 min with a molar ratio of n(Si)∶n(Ni)=2∶1.When the silicon was further ball milled into nano particles(around 100nm),the Si-centered self-scattered SiNWs growing in radial were formed and each single SiNWs was about 150 nm in diameter and 1.5μm in length.