Effects of W Content on Structural and Mechanical Properties of TaWN Films

Abstract

In this study, TaWN films were fabricated through co-sputtering. The effects of W addition on the structural variation and mechanical properties of these films were investigated. TaWN films formed face-centered cubic (fcc) solid solutions. With the increase in the W content, the fcc phase varied from TaN-dominant to W2N-dominant, which was accompanied by a decrease in the lattice constant and alterations in material characteristics, such as the chemical bonding and mechanical properties. The phase change was further correlated with the bonding characteristics of films examined by X-ray photoelectron spectroscopy. The hardness increased from 21.7 GPa for a Ta54N46 film to 23.2-31.9 GPa for TaWN films, whereas the Young's modulus increased from 277 GPa for the Ta54N46 film to 302-391 GPa for the TaWN films. The enhancement in films' mechanical properties was attributed to the strengthening of the solid solution and the phase change. The wear behavior of the fabricated TaWN films was evaluated using the pin-on-disk test. The Ta17W55N28 and Ta36W24N40 films exhibited an abrasive wear behavior and low wear rates of 4.9-7.6 x 10(-6) mm(3)/Nm.