Microstructure, mechanical and tribological properties of CWNr films deposited by DC magnetron sputtering

Chromium tungsten nitride (CrWN) films were deposited on silicon substrates using a d.c. magnetron reactive co-sputtering technique equipped with 45 degrees dual guns of Cr and W targets. The morphology and microstructure of the films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and electron probe micro-analyses (EPMA). The mechanical and tribological properties were evaluated using a nanoindentor and a conventional ball-on-disk tribometer, respectively. The as-deposited films have nanocomposite microstructure which CrN is the main crystalline constituent inside. The nanocomposite CrWN films exhibit a low surface roughness (Ra < 11 nm), and a highest hardness of approximately 25.1 GPa. The wear test results show that the CrWN film has a variable coefficient of friction between 0.15 and 0.3 depending on the W contents within the film. (C) 2012 Elsevier Ltd. All rights reserved.