Single-source precursor synthesis of a compositionally complex early transitional metal nitride (V, Nb, Ta, Mo, W)Nx and its high temperature stability

Abstract

Compositionally complex transitional metal nitrides are an interesting class of ceramics with superior chemical, thermal, and mechanical stability, with a high potential in ultra-high temperature applications and catalysis. The exceptionality in the properties may partly be explained as a consequence of their high configuration entropy. Although promising candidates, the bulk synthesis of compositionally complex metal (carbo)nitrides remains challenging, often limited by purity and scalability due to significant oxygen contamination from gaseous reactants or nitrogen loss. To offset these disadvantages, the current manuscript proposes an alternative synthesis route for the synthesis of a compositionally complex nitride (V, Nb, Ta, Mo, W)Nx, which deviates from the typical solid-state and sputtering methods by employing an organometallic precursor route and a double ammonolysis process. This is a first attempt to synthesize such ceramics with low oxygen contamination in compositionally complex (carbo)nitrides with a scalable production. Using a multidisciplinary approach consisting of theoretical methods and experiments, the current study elucidates the evolution and stability of the precursor at high temperatures under carbon, and thereby obtained ceramics at different temperatures.