Nanomechanical properties evaluation of chromium nitride films by nanoindentation and nanowear techniques

Nanomechanical and nanotribological properties studies are needed to develop fundamental understanding of surface and interfacial phenomena on the nano scale. In this study, nanoindentation, nanoscratch and nanowear tests were employed to characterize the nanomechanical and nanotribological properties of both reactive r.f. magnetron sputtered and cathodic arc plasma deposited chromium nitride (CrN) thin films. Surface morphologies and roughness of CrN films on the nanoscale were explored. The nanohardness and elastic modulus of CrN films were evaluated using the nanoindentation method. Coefficient of friction of CrN films against a conical diamond tip was also calculated based on the nanoscratch data. Reciprocating nanowear tests on these two CrN films were conducted with 300,400 and 500 μN normal loads. Residual wear depths of the two CrN films were examined by an atomic force microscope (AFM). The residual wear depths of two CrN films after reciprocating nanowear tests ranged from 4 to 7.5 nm under 300 to 500 μN loads, respectively. It was found that the r.f. sputtered CrN film exhibited higher nanohardness and better surface roughness value. The r.f. sputtered CrN film showed more nanowear resistance and lower coefficient of friction than the cathodic arc plasma deposited one.