Theory of Microwave Effects on Atomic Diffusion in Sintering: Basic Considerations of The Phenomenon of Thermal Runaway

We present the results of our recent studies of the possible origin of the reported increase in sintering efficiency brought about by the application of microwaves. We study the phenomenon of thermal runaway in ceramic materials undergoing microwave heating and present a theory on the basis of a simple temperature-time equation. The nonlinear evolution inherent in the equation arises naturally from physical considerations. The theory is applied to experimental observations reported on several different materials including silica, alumina, strontium titanate, zinc oxide and iron oxide, and shown to be in good agreement with the data.