(Ti0.2V0.2Cr0.2Nb0.2Ta0.2)2AlC–(Ti0.2V0.2Cr0.2Nb0.2Ta0.2)C high‐entropy ceramics with low thermal conductivity

Abstract In recent years, the microstructure and physicochemical properties of high‐entropy ceramics have received much interest by the combination of multiple principal elements. Herein, (Ti 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 ) 2 AlC–(Ti 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 )C high‐entropy ceramics (M 2 AlC‐MC HECs) were prepared by the spark plasma sintering (SPS) technique, attributing to the structural and chemical diversity of MAX phases. The microstructure of M 2 AlC‐MC HECs was characterized from micron to atomic scales, and the phase composition of M 2 AlC‐MC HECs was analyzed by a combination of Maud and Rietveld analysis. The results indicate the successful solid solution of Ti, V, Cr, Nb, and Ta atoms in the M‐site of the 211‐MAX configuration, and all the samples show a classic layered structure. The weight percentage of (Ti 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 ) 2 AlC in the M 2 AlC‐MC HECs was more than 90%. Furthermore, the thermoelectric properties of M 2 AlC‐MC HECs were investigated for the first time in this study, and the electrical conductivity and thermal conductivity of HECs are 3278 S cm −1 and 2.78 W m −1 K −1 at 298 K, respectively.