Structure and properties of duodenary (TiVCrZrNbMoHfTaWAlSi)N coatings by reactive magnetron sputtering

Highlights: • The (TiVCrZrNbMoHfTaWAlSi)N coatings with R_N was synthetized • The structural evolution and physical properties with R_N was demonstrated • High mixing entropy during lower free entropy of the solid solution phase is evident. • High R_N leads to increased metal–N bonds and residual stress. • The hardness of the coatings is enhanced up to 34.8 GPa. The influence of the N₂-to-total (N₂+Ar) ratio (R_N) on the structure and properties of duodenary (TiVCrZrNbMoHfTaWAlSi)N coatings with markedly high mixing entropy is investigated. The coatings are deposited by DC reactive magnetron sputtering with an equimolar TiVCrZrNbMoHfTaWAlSi target. No external bias and heating are applied to the substrate. An increase in R_N contributes to an increase in N concentration, residual stress, and lattice parameter. At low R_N, the coatings have an amorphous structure. When R_N is 15%, an FCC nanocrystal structure with (200)-preferred orientation appears. When R_N increases to 20%, HCP nitride nanocrystals coexist with coarse columnar grain FCC structures with (111)-preferred orientation. As R_N increases to 50%, the grain size decreases, and their preferred FCC orientation returns to (200). Given that the mechanical and electro-optical properties are strongly correlated with R_N, the hardness of the coatings is enhanced up to 34.8 GPa. However, the electrical conductivity and light reflectivity at 0.62 eV deteriorate from 5319 S/cm to 62.1 S/cm and from 71.2% to 42.8%, respectively. These results provide a valuable basis for the future development of high-entropy nitrides.