Flash sintering of ZnO ceramics at 50 °C under an AC field

We examined the flash sintering behavior of zinc oxide nanopowder at an onset furnace temperature as low as 50 °C without sintering aids under an AC electric field up to 2800 V/cm. As the electric field applied in the specimens increased and the flash sintering occurred in air, the onset furnace temperature decreased from 190 to 126 °C, while with the thermal insulation method, the onset furnace temperature decreased to 50 °C. The surface temperature of the specimens was observed with a thermal infrared camera, and the peak temperature was 1404 °C. A high density >92% was achieved with thermal insulation flash sintering and an electric field of 2800 V/cm.