Non-thermal interactions between high-strength microwave fields and ceramics

Summary form only given, as follows. Numerous claims have been made of observations that microwave heating of ceramics promotes faster processing or solid state reaction rates than in conventional furnace heating. Explanations for these observations, as well as the observations themselves, have caused some controversy since then is no verifiable theoretical explanation. Issues of sample temperature measurement also complicate the matter. Our previous experiments with ionic conduction indicated the existence of microwave-induced charge flow in ionic materials due to a high-frequency "ponderomotive" rectification near crystal surfaces. Numerical modeling of high-frequency "ponderomotive pressure" shows that microwave fields can affect the near-surface-layer concentration of defects in ionic materials. The magnitude of this effect is investigated over a range of temperatures, frequencies, field strengths, and material doping. The simulations are also used to determine what role this "microwave effect" could have on diffusion, sintering, and other thermal processing. The results of the computer simulations are compared to experimental measurements of ionic conduction and diffusion.