Mechanical properties of interference thin films on colored stainless steel evaluated by depth-sensing nanoindentation

Aiming to evaluate the influence of morphology on mechanical properties of interference films, electrodeposited using alternating pulse current on AISI 304 stainless steel, depth-sensing nanoindentation was employed. Film porosity was measured in field emission scanning electron microscopy images. Surface roughness of the films was evaluated by atomic force microscopy. Dry wear resistance under a load of 30 N against a strip of CrO3 0.5 μm abrasive paper was also measured. Load–displacement response of a Berkovich indenter reveals that the interference films analyzed are softer than the uncoated substrate. Nanoscratching and wear resistance decrease as the porosity of the interference films increases. A linear relation between film hardness and its porosity was obtained. By correlating film properties with process parameters, it was found that the mechanical resistance of the interference film is controlled by the pulse size employed in the electrochemical reaction.