Behavior of microwave-heated silicon carbide particles at frequencies of 2.0–13.5 GHz

Silicon carbide is a key material in microwave (MW) processing and is used widely as a thermal insulator and catalytic agent. In this study, we experimentally investigated the temperature dependence of the MW-absorption properties of SiC particles at frequencies of 2.0–13.5 GHz. We heated SiC particles of different sizes using MW radiation. The heating behaviors of the particles were then compared with their MW-absorption properties. The heating behavior of the particles was dependent on their radii; this result was in keeping with theoretical predictions. Furthermore, the β-SiC particles exhibited anomalous behaviors when subjected to microwave heating at temperatures of 1100 °C and higher. These behaviors were attributable to the transformation of β-SiC into the α-phase. The underlying mechanism for this transformation is discussed on the basis of the results of X-ray diffraction analysis.