Tribological properties of a-C/Cr(N) coatings in micro-and nano-scales

This research was involved with comparison study of tribological properties of a-C/Cr(N) multilayered coatings in micro-and nano-scales. The a-C/Cr(N) coatings were deposited on Si wafers and M2 steel substrates by unbalanced magnetron sputtering of one Cr and two C targets. Cross-section TEM analysis was used to determine the layer periodicity of the coatings. Nanoindentation was used to measure hardness (H) and elastic modulus (E), and also perform nanowear tests. Pin-on-disc tribological tests were conducted to evaluate tribological properties of the coatings in micro-scales. H / E, H3 / E2, and hf / hmax values were calculated for predication of wear performance of the coatings. It was found that the ranking of coating wear resistance was consistent to the order of H / E, H3 / E2, and hf / hmax values. The coating with a periodicity of 4 nm had the highest hardness and the best wear resistance in both nano-and micro-scales.