Effects of nitrogen flow ratio on the structural, mechanical, and anticorrosive properties of co-sputtered (NbTaMoW)Nx films

Abstract

In this study (NbTaMoW)Nx films were fabricated through reactive co-sputtering using four pure-element targets at various nitrogen flow ratios (RN2). It was also explored the phase structures, mechanical properties, and corrosion resistance properties of these films. The results indicated that the stoichiometric ratio x of the (NbTaMoW)Nx films increased with increasing RN2, accompanied by body-centered cubic metal phases transformation to face-centered cubic covalent nitride phases. These face-centered cubic phases were classified into phases with M2N-dominant and phases with MN-dominant structures. The results also indicated that the (NbTaMoW)Nx films prepared at RN2 values of 0.2–0.4 exhibited high hardness and Young's modulus values of 29.3–31.7 and 333–396 GPa, respectively. Using potentiodynamic polarization and electrochemical impedance spectroscopy, it was determined that the corrosion resistance of the SUS420 substrate was effectively improved with the deposition of one nitrogen-free NbTaMoW film and four nitrogen-containing (NbTaMoW)Nx films. It was also observed the highest corrosion resistance in the (Nb0.16Ta0.29Mo0.32W0.23)N0.07 film because of its dense microstructure.