Synthesis of single-phase high-entropy carbide powders

High-entropy carbide powders were produced by a two-step synthesis process consisting of carbothermal reduction followed by solid solution formation. Nominally pure (Hf,Zr,Ti,Ta,Nb)C in a single-phase rock salt structure had an average particle size of about 550 nm and an oxygen content of 0.2 wt%. The fine particle size was due to the use of high-energy ball milling prior to carbothermal reduction combined with the relatively low synthesis temperature of 1600 degrees C. Oxygen content was minimized by completion of the carbothermal reduction reactions under vacuum. This is the first report of synthesizing a high-entropy carbide powder using individual transition metal oxides and carbon as precursors. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.