On the hardness and the inherent ductility of chromium carbide nanostructured coatings prepared by RF sputtering

Abstract

Homogenous and nanostructured chromium carbide thin coatings are prepared by RF sputtering. The nanoindentation tests are used to investigate the evolution of plastic deformation and hardness as a function of the grain size. The Cr 3C 2 films have been deposited on magnesium oxide substrates from a Cr 3C 2 target in pure argon atmosphere. Based on the effect of the deposition temperature, we have generated nanostructured Cr 3C 2 coatings with different mechanical properties. We have found that both crystalline texture and grain size increased with increasing the deposition temperature. The nanostructured chromiumcarbide film with grain size in the order of 5 nm, prepared at a deposition temperature of 600 °C, showed a higher hardness as well as a good ductility compared to the samples prepared at 850 °C or at room temperature. The cyclic nanoindentation measurements at constant loading rate allowed qualitative characterization of the change in the irreversible plastic work for the samples considered in this report.