Structure and Friction Behavior of CrNx/a-C:H Nanocomposite Films

CrN and CrNx/a-C:H nanocomposite films were deposited on Si substrates by the magnetron sputtering technique. The structure, chemical state, and friction behavior of the CrNx/a-C:H films prepared at various CH4 content were studied systematically. The CrN film shows strong (111) and (220) orientation, while the CrNx/a-C:H films consist of the nanocrystalline CrNx or Cr particles embedded in an amorphous hydrocarbon (a-C:H) matrix and show weak diffraction peaks, which is in accordance with the XPS analysis results. The typical Raman D and G peaks are observed, indicating that the separated amorphous carbon or CNx phase appears in the CrNx/a-C:H films. However, no chromium carbide was observed in all the as-deposited samples. From the SEM graphs, all the deposited films depicted a dense and compact microstructure with well-attached interface with the substrate. The average friction coefficient of the CrNx/a-C:H films largely decreased with increasing CH4 content