Ultra fine Al_2O_3/SiC powders have been synthesized by microwave-induced combustion reaction. Characteristics of microwave heating such as volumetric heating; uniform distribution and rapid heating rate were favorable to the combustion synthesis of powders. The exothermicity of the redox reaction in the aluminium nitrate, SiC and urea mixture produces high temperatures, above 1100 °C, as demonstrated by the formation of α-Al_2O_3 phase. The mechanism of temperatures, the microwave oven was favorable to the uniform emission of gases and uniform, and fast dissipation of heat, promoting formation of different and powders with characteristics that were different from those produced conventionally. The dispersion of SiC in the alumina matrix was assured by the direct conversion of liquid solution to the final solid product, and the segregation of the initial constituents, commonly found in conventional mixing of powders (alumina-SiC) was avoided. The presence of SiC increased the flame time of the combustion reaction and there was no evidence of any form of SiO_2 and/or mullite phases. Thus, the SiC particles were not oxidized during the reaction and partial reaction with alumina did not occur; SiC particles remained as a distinct and separate phase.
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