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 40°C. 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°C to 1500°C 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.