添加剂对稻壳合成SiC的影响

Effect of Admixtures on Synthesis of Silicon Carbide

以稻壳作为硅源和碳源,不同掺量的Al2O3、Nd2O3、CeO2等作为添加剂,用碳热还原法在1 500℃条件下成功合成了SiC。利用XRD分析了试样在烧成过程中的物相变化,用SEM观察了试样的显微结构。结果表明,当无添加剂时,稻壳在1 550℃下仅能形成少量SiC,掺入Al2O3、Nd2O3、CeO2,均能促进SiC的形成。其中,掺3.5%Al2O3于1 500℃下烧成试样的SiC合成率最高,达到89.12%。

SiC was prepared at 1 500 ℃ by carbothermic reaction using the rice husk as silica source and carbon source,and Al2O3,Nd2O3,CeO2 as additives.The mineral phase changes during sintering were analyzed by X-ray diffraction（XRD）,then the microstructures of the sintered samples were observed by scanning electronic microscopy（SEM）.The results showed that the SiO2 and C in rice husk could react to form a little of SiC at 1 550 ℃,and doped Al2O3、Nd2O3、CeO2additives all can promote the formation of SiC of samples.Among several additives,the SiC product rate of the sampale doped 3.5% Al2O3 is up to 89.12%.