Nitriding high entropy alloy films: Opportunities and challenges

High entropy nitride (HEN) films have attracted much attention due to their versatile properties, such as satisfactory mechanical properties, excellent anti-oxidation performance, outstanding corrosion resistance, and vitally important thermostability, indicating high application potentials. This paper reviews the four core effects and discusses several empirical parameters for phase prediction in HEAs. Then, this review focuses on the recent developments of HEN films, introducing how N contents as well as other factors influences the microstructures and thus leads to changes in relevant properties, such as mechanical, tribological, and chemical stabilities, what follows is the related mechanisms contributing to. Lastly, future trends and outlooks are briefly introduced. This review is aimed to give a comprehensive introduction to recent developments in HEN films, and to make it convenient to explore the research gaps for students and researchers.