Oxidation behaviours of high-entropy transition metal carbides in 1200 degrees C water vapor

摘要

High-entropy (Zr,Ti,Hf,Nb,Ta)C ceramic with single-phase rock salt structure was prepared by spark plasma sintering and their oxidation behavior was investigated at 1200 degrees C water vapor atmosphere. Results indicate that high-entropy carbides exhibit high oxidation resistance with a small mass gain per unit area of 6.6 x 10(-2) kg/m(2) after oxidation for 5 h. The parabolic rate constant k(p) of (Zr,Ti,Hf,Nb,Ta)C ceramic is almost two order of magnitude lower than that of ZrC ceramic. The high oxidation resistance is generally ascribed to the large lattice distortion and the formation of dense oxide scale which significantly suppressed the metal elements and H2O diffusion. (C) 2019 Elsevier B.V. All rights reserved.