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, (C 2 H 5 ) 4 SiO 4 ) ) and saccharose (C 12 H 22 O 11 ) as starting materials. Silica sol is prepared by hydrolyzed TEOS with deionized water, ethanol (CH 3 CH 2 OH) 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.