Microwave heating characteristics of graphite based powder mixtures

The choice of material for a crucible is essential in hybrid microwave heating and graphite is one of the strong microwave absorbers which can sustain high temperatures. Experiments were carried out to investigate the microwave heating behavior of graphite combined with other materials to enhance efficiency. Mixtures comprising of graphite and magnetite or graphite and silicon carbide were found to have better microwave heating properties than pure components. The enhancement was likely due to microplasma generated by graphite in a microwave environment. Microwave heating of graphite–silicon carbide mixtures provided the best results in terms of high heating rates without arcing. The optimal combination of graphite–silicon carbide was identified and can be used as a starting material for making efficient crucibles and susceptors.