Tribological Behavior of (CrAlVTiNbMo)N_x High‐Entropy Nitride Coatings Over a Wide Temperature Range

Herein, the (CrAlVTiNbMo)N x high‐entropy nitrides (HENs) coatings are successfully fabricated by high‐power impulse magnetron sputtering. Research on the microstructure of HENs coatings and their tribological properties over a wide temperature range is conducted, while the mechanical properties and phase stability of the coating surface after friction tests at different temperatures are also analyzed. From room temperature (RT) to 400 °C, the HENs coating exhibits a preferential orientation with a face‐centered cubic structure along the (200) plane. However, the coating mainly consists of oxide phases at high temperature (600 °C), which exhibit self‐lubricating properties and contribute to a lower friction coefficient (0.18). As the temperature increases, the main wear mechanisms of the coating transition from adhesive wear to abrasive wear, and then, to oxidative wear. The dense, continuous, and smooth tribo‐layers formed on the friction surface, can significantly reduce the friction coefficient of the coating at 600 °C. The coatings exhibit high hardness and L C3 values after friction tests at RT to 400 °C. However, these values decrease after friction at 600 °C, indicating high‐temperature softening.