Effect of insulation materials and power on microwave heating characteristics of SiC susceptor under material-specific parametric conditions

High-quality microwave absorber materials play a crucial role in the efficient and uniform processing of variety of materials through microwave hybrid heating. Silicon carbide (SiC) is an excellent microwave absorber at room temperature, which enhances the heating rate of the target materials significantly. In the present study, effects of heat insulation materials and their configurations on microwave heating characteristics of SiC were investigated at different power levels. The responses were assessed in terms of the heating capability (maximum temperature achieved), radiation heat loss, temperature gradient, and heating uniformity under different parametric conditions. A 3D COMSOL Multiphysics simulation model, coupled with microwave heating and heat transfer module, was developed with surface-to-ambient radiation boundary conditions. Electromagnetic and thermal properties of the SiC utilized in the model were selected based on physical properties, such as porosity/density, particle size, and chemical composition of SiC. The model outputs were validated with experimental findings. Results showed that microwave heating characteristics were highly sensitive to the susceptor (SiC) properties, insulation materials and power levels. Insulation materials prevented heat losses significantly; at the same time, different insulation configurations altered the electrical field intensity distribution within the SiC sample, which affected the responses. Microwave power levels also influenced the responses and quantity of insulation required.