Structural and mechanical characterization of Cr-Ta-N hard coatings prepared by reactive magnetron sputtering

The tribological and mechanical properties of hard coating materials may be improved through alloying. In this study, Cr-N coatings are alloyed with Ta and the resulting structure and mechanical properties were studied. Cr-Ta-N coatings with a range of Ta concentrations were deposited on oxidized silicon substrates in a reactive Ar + N-2 atmosphere by using a d.c. magnetron sputtering unit. Pure Cr-N and Ta-N films were also deposited for comparison purposes. The composition and structure of the coatings were evaluated by electron microprobe analyzer and X-ray diffraction respectively. The hardness and elastic moduli of the coatings were measured by nanoindentation as a function of composition and nitrogen partial pressure.