High-temperature wear mechanisms of TiNbWN films: Role of nanocrystalline oxides formation

Abstract Refractory high/medium entropy nitrides (HENs/MENs) exhibit comprehensive application prospects as protective films on mechanical parts, particularly those subjected to sliding contacts at elevated temperatures. In this study, a new MEN system TiNbWN, forming single fcc solution, is designed and its wear performance temperatures ranging from 25 750 °C explored. The mechanisms can be rationalized by examining the subsurface microstructural evolutions using transmission electron microscopy well calculating phase diagrams interfacial adhesion behavior employing calculation of diagram (CALPHAD) density functional theory (DFT). To specific, increased losses occur in temperature range 25–600 °C, being predominantly caused thermally-induced hardness degradation; whereas ultimate (750 °C), loss refrained due formation nanocrystalline oxides (W n O 3 −2 , TiO 2 γ x ), synergistically revealed CALPHAD, which not only enhance properties pristine nitride film, but also act solid lubricants, reducing adhesion. Thus, our work delineates role situ formed mechanism transition TiNbWN thin films, could shed light high-temperature refractory HEN/MEN films.