Synthesis of silicon carbide fromcoal fly ash and activated carbon powder

Micrometer silicon carbide powder has been synthesized from coal fly ash and activated carbon powder. Calcinated Suralaya fly ash used as SiO2 resources on carbothermal reduction process with activated carbon powder. Particle size of activated carbon powder is < 32 mm. Synthesis process has been carried out on temperature 1200 oC and and 1300 oC on vacuum atmosphere under argon flow. Holding time for all synthesis is 2 hour. Synthesis products were analyzed by XRD with Cu-Ka radiation, FT – IR spectrophotometer and SEM fitted with EDAX. SiC powder with particle size about 5 mm were successfully synthesized at temperature 1300 oC. Key word: Silicon carbide, coal fly ash, carbon powder. high hardness, excellent resistance to oxidation and corrosion, low coefficient of thermal expansion, high heat-transfer capability, excellent thermal stabilities and chemical inertness2,3. Silicon Carbide can be produced by chemical vapor deposition (CVD) and carbothermal reduction. Chemical vapor deposition (CVD) is a chemical process used to produce highpurity, high-performance solid materials. In a typical CVD process, the substrate is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber4. The carbothermal reduction is relative simple and time-cost effective technique, in this process : mixture of carbon and silica or silicon is heated in a reactor in an inert atmosphere5. Reaction between carbon and silica to form SiC is as follows6,7: 252 Sulardjaka et al., Mat. Sci. Res. India., Vol. 6(2), 251-256 (2009)