Comparison in mechanical and tribological properties of Cr–W–N and Cr–Mo–N multilayer films deposited by DC reactive magnetron sputtering

Cr–W–N and Cr–Mo–N films were deposited on high speed steel substrate by unbalanced DC reactive magnetron sputtering. Cross-sectional scanning electron microscopy (SEM) morphologies of the films confirmed that the bilayer thickness of multilayer became thinner, and then structural transformation occurred from multilayer to composite with increasing the rotation velocity of substrate holder. X-ray diffraction (XRD) patterns indicated that the Cr–W–N films were composed of CrN and W2N crystalline phases, and the Cr–Mo–N films consisted of crystalline CrN and amorphous/nanocrystalline Mo2N. Mechanical and tribological properties were investigated by using a nanoindentor and a ball-on-disk tribometer, respectively. The Cr–W–N films exhibited excellent mechanical properties and wear resistance, while Cr–Mo–N films showed lower friction coefficient. Optimal mechanical and tribological properties were obtained in the Cr–W–N multilayer film with a bilayer period of 12 nm.