The effect of plasma-assisted ball milling on preparation and sintering behavior of (Zr0.1429Hf0.1429Ce0.1429Y0.2857La0.2857)O2-δ high entropy fluorite oxide

The sintering process of high entropy fluorite oxide ceramics prepared by the conventional solid-phase reaction method suffers from high single-phase synthesis temperature, low densities, and abnormal grain growth. To improve the sintering characteristics of high entropy fluorite oxide ceramics, the oxide mixture was dealt with dielectric barrier discharge plasma-assisted ball milling. The samples were analyzed using XRD, SEM, TEM, TG/DTG, visual high-temperature deformation analyzer, and nanoindentation meter. The results show that the plasma field activates the raw material powder and promotes powder finer. The rapid heating effect of the plasma during the ball milling process causes micro-area sintering and micro-area melting on the powder surface, which increases the active sites of the solid phase reaction of the material, accelerates the mass transfer process, and improves the sintering activity. Compared with conventional ball milling, plasma-assisted ball milling reduces the single-phase synthesis temperature of high entropy ceramics from 1500 °C to 1300 °C. The sintered ceramic pellets have intact grain growth, no noticeable abnormal grain growth, and improved density and mechanical properties.