Densification and grain growth in the flash sintering of high-entropy (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7 ceramics

Preparation of high-entropy ceramics (HECs) requires long duration at high temperatures, which limits their wide application. In this study, high-entropy (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7 ceramics was prepared at low temperatures of 762-885 degrees C in very short time of 60 s using the flash sintering. The effects of electric field strength and current limit on the densification and grain growth, as well as the phase transformation were systematically investigated. Both density and grain size were increased with the increase of the electric field strength and current limit. The phase transformation from defective fluorite to pyrochlore occurred at large current limit. The flash-sintered bulks exhibited good mechanical properties. This study demonstrates that flash sintering is an effective method for rapid preparation of HECs at low temperatures. Moreover, the microstructure of HECs can be controlled by adjusting the electric field strength and current limit.