Mechanical and Tribological Properties of Laminated (NbTaMoW)N Films

Laminated (NbTaMoW)N films were prepared via co-sputtering. The sputtering variables were a substrate holder rotation speed of 2 and 10 rpm and a nitrogen flow ratio (f_N2 = N₂/(Ar + N₂)) of 0.1, 0.2, and 0.4. The (NbTaMoW)N films fabricated at 30 rpm displayed columnar structures. The phase structures of the laminated (NbTaMoW)N films varied from multiple body-centered cubic phases to a nanocrystalline and a face-centered cubic phase as the f_N2 increased from 0.1 to 0.2 and 0.4. The mechanical and tribological properties of the laminated (NbTaMoW)N films were evaluated. The laminated (NbTaMoW)N films deposited at an f_N2 of 0.4 had hardnesses of 25.2 and 26.1 GPa when prepared at 2 and 10 rpm, respectively, lower than the value of 29.9 GPa for the columnar (NbTaMoW)N film prepared at an f_N2 of 0.4 and 30 rpm. In contrast, the wear resistances of the laminated (NbTaMoW)N films were superior to those of the columnar (NbTaMoW)N films.