Synthesizing Al2O3/SiC in a microwave oven: A study of process parameters

The effect of precursor milling, reaction time, microwave power level and gas flow on the microwave synthesis of Al2O3/SiC composite powder was investigated. Reactions were carried out in a semi-industrial microwave oven (Cober Inc., USA) allowing for the insertion of inert gas. Two reaction configurations were designed to perform the synthesis: a cylindrical thermally-insulated reactor and a pipe fluidized bed reactor (PFR). The precursor employed for the reaction in the two reactors was utilized in the form of pellets. A direct relation exists between saturation of the reaction atmosphere and the kinetics of carbothermal reduction. In addition to high levels of microwave radiation power (>1.5 kW), this favors the rapid formation of Al2O3/SiC.