Formation and properties of Ca2+ substituted (Ce0.2Zr0.2Ti0.2Sn0.2Hf0.2)O2 high-entropy ceramics

Five equimolar multicomponent oxides were synthesized by replacing one of five cations in (Ce 0.2 Zr 0.2 Ti 0.2 Sn 0.2 Hf 0.2 )O 2 with Ca 2+ . The results reveal that except for the one in which Ce 4+ replaced by Ca 2+ , the other four components can form single-phase high-entropy fluorite oxides (HEFOs) at different temperatures, which indicates that Ce 4+ is very important for the formation of single-phase HEFOs. The sintering behavior, lattice parameter and properties containing density, porosity, flexural strength and thermal conductivity of the four single-phase HEFOs were investigated. With the change of substituted ions, grain size, relative density, flexural strength and thermal conductivity of the materials vary greatly, which are correlated to the size disorder and mass disorder of these materials. The results of this paper provide a reference for the composition designing and performance tailoring of equimolar HEFOs.