Microwave sintering of large size pieces with complex shape

In this study, large size pieces of kaolin with a complex shape were successfully sintered in a microwave multimode cavity. The challenge was to obtain a sample homogeneously sintered on a large surface. For this purpose, prior to sintering, a finite element modelling study was carried out to determine the optimal experimental set-up configuration permitting to have an electromagnetic field as homogenous as possible around the sample. In this case, it was pointed out that the hybrid heating configuration (use of susceptors) was the most suitable configuration. The samples experimentally obtained were structurally and mechanically characterized. Therefore, it was highlighted that the microwave sintered samples present a microstructure and mechanical properties similar to those of samples conventionally processed for a lower sintering temperature. Finally, the microwave sintering permit to significantly reduce the energy consumption required for the production of sintered ceramic pieces, which is crucial for sustainable development.