Preparation of nanometer silicon carbide powders by sol-gel processing

Nanometer silicon carbide powders are synthesized by sol-gel and carbothermal reduction processing with TEOS(tetraethoxysilane, (C₂H₅)₄SiO₄) and saccharose (C₁₂H₂₂O₁₁) as starting materials. Silica sol is prepared by hydrolyzed TEOS with deionized water, ethanol (CH₃CH₂OH) as cosolvent and hydrochloric acid as catalyst. It further dehydrated to make colorless and transparent gel and dried to obtain drying gel at 40degC. Carbothermal reduction of the prepared silica/saccharose composites is carried out in argon atmosphere of 500 Pa in a high vacuum furnace at temperatures ranging from 1200 degC to 1500 degC to form powders. The surface morphology and crystal structure of nanometer SiC powders have been investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and Raman spectrum. Experimental results show that the samples have better crystalline state and its typical diameters reach nanometer magnitude.