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

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 Cr3C2 films have been deposited on magnesium oxide substrates from a Cr3C2 target in pure argon atmosphere. Based on the effect of the deposition temperature, we have generated narrostructured Cr3C2 coatings with different mechanical properties. We have found that both crystalline texture and grain size increased with increasing the deposition temperature. The narrostructured chromiumcarbide film with grain size in the order of 5 nm, prepared at a deposition temperature of 600 degrees C, showed a higher hardness as well as a good ductility compared to the samples prepared at 850 degrees 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. (C) 2008 Elsevier B.V. All rights reserved.