Complete Elimination of Pest Oxidation by High Entropy Refractory Metallic Silicide (Mo 0.2W 0.2Cr 0.2Ta 0.2Nb 0.2)Si 2

Abstract

Molybdenum disilicide (MoSi₂) is a competitive ultra-high-temperature structural material. However, it suffered from a fatal low-temperature oxidation, which extremely limited its application. To solve this problem, a novel high entropy refractory metallic silicide with composition of Mo_0.2W_0.2Cr_0.2Ta_0.2Nb_0.2)Si₂ was synthesized by in-situ spark plasma reaction sintering in this work. The interrupted oxidation testings at 500 °C for 300 h have been performed, and shown that this material has an excellent oxidation resistance at low temperatures without pest phenomenon. The mechanism for eliminating pest oxidation is that the high entropy of this material would suppress generation of bulk metallic oxides with formation of only an intact SiO2 film during oxidation testing.