催化剂对以硅溶胶为硅源合成碳化硅晶须的影响

Effect of Catalysts on Synthesis of Silicon Carbide Whiskers with Silica Sol

以硅溶胶和炭黑为原料，金属硅、三氧化二铁和硅铁合金为催化剂，采用碳热还原法合成碳化硅晶须，通过XRD及SEM对合成产物的物相及形貌进行分析，探讨了合成温度、催化剂种类、催化剂加入量对合成碳化硅晶须的影响。结果表明：在原料中加入催化剂，合成碳化硅晶须的最佳温度为1550℃；以Si—Fe合金为催化剂合成碳化硅晶须的效果明显好于以Fe2O3和金属硅为催化剂合成效果；Si—Fe合金加入量（占SiO2质量分数）为1％时，晶须生成率高，成直线形，长度10—50μm，直径0．1～0．3μm。

Silicon carbide whiskers were prepared by carbothermal reduction method. Materials are silica sol and carbon black,Si,Fe2O3 ,Si-Fe as catalyst, the phase composition and microstructure of compound products were investigated by XRD and SEM, effect of synthesized temperature, kind of catalysts, amount of catalyst were discussed. The results showed that silicon carbide whiskers were synthesized by silica sol and black carbon, add catalyst, synthesis temperature is 1550 ℃. Synthesis effect of silicon carbide whiskers with Si-Fe is better than Si and Fe2O3. Adding amount of Si-Fe is 1% , synthesized rate of silicon carbide whiskers is high, it is straight, length is 10-50 μm, diameter is 0.1-0.3 μm.