Microstructure and mechanical properties of microwave sintered (MgCoNiCuZn)O high-entropy ceramics

The microstructure, reaction mechanism and mechanical properties of (MgCoNiCuZn)O high-entropy ceramics prepared by microwave sintering technology were studied. Single-phase (MgCoNiCuZn)O high-entropy ceramics can be prepared in about 1 h when the preforming pressure is 5 MPa and the temperature is higher than 900 °C. By analyzing the microscopic morphology and density, it can be known that the density gradually increases with the increase of temperature. When the temperature is higher than 1000 °C, the pores in the sample indicate the packing, agglomeration and segregation of Cu2+ atoms at the grain boundaries. When the mass of the raw material is 20 g, it exhibits a good impedance matching effect during microwave heating. The sintered (MgCoNiCuZn)O ceramic with a density of 92.87 %, a flexural strength of 290 ± 20 MPa, an elastic modulus of 187.05 ± 5 GPa, and a microhardness of about 7 GPa.