Facile Electrochemical Synthesis of Nanoscale (TiNbTaZrHf)C High-Entropy Carbide Powder.

High-entropy alloys and compounds are becoming an important class of new materials due to their outstanding refractory and high-temperature properties. However, preparation in bulk quantities and in powder form via classical metallurgical methods is challenging. Here, we report the first synthesis of an ultra-high-temperature high-entropy carbide, (TiNbTaZrHf)C, via a facile electrochemical process. In this, a mixture of the individual metal oxides and graphite is deoxidised in a melt of CaCl2 at a temperature of only 1173 K. The (TiNbTaZrHf)C prepared is single-phase fcc and has a powdery morphology with a particle-size range of 15-80 nm. Such materials are in demand for modern additive manufacturing techniques, while preliminary tests have also indicated a possible application in supercapacitors. The successful synthesis of (TiNbTaZrHf)C powder may now guide the way towards establishing the electrochemical route for the preparation of many other entropy-stabilised materials.