Factors affecting preparation of high specific surface area silicon carbide

A sol-gel process catalyzed by oxalic acid was used for the preparation of SIC precursor from raw materials of tetraethyl orthosilicate (TEOS) and sucrose. The precursor thus obtained was homogeneous. Sintered with a certain heating program (1350 similar to 1600 degrees C) in an argon flow, the precursor was converted into the high surface area SIC. The effect of the amount of water, nickel nitrate and the molar ratio of C/Si on the surface area of SIC were studied. The results show that when the molar ratio of H2O/TEOS, C/Si and nickel nitrate/TEOS is 7.5, 4, 0.005, respectively, the gel formation time is the shortest. The temperature for carbothermal reduction could be lowered by 200 degrees C when the nickel nitrate is added into the precursor.