On the correlation between the thermal instability onset and the flash sintering event

Abstract In the experiments on microwave sintering of alumina ceramics at high levels of the volumetrically deposited power a long delay, on the order of 100 s, is observed between the development of thermal instability and the onset of rapid (“flash”) densification. The observed delay demonstrates the causal relationship between the thermal instability development, accompanied by liquid phase formation, and the occurrence of rapid densification resulting from a change in the sintering mechanism.