Antifriction effects of Cu2S film on Ni-based MMC coating.

Self-lubricating sulfide films have gained increasing interest because of their outstanding properties and promising functions in a wide range of applications. In this study, thin cuprous sulfide (Cu 2 S) films with a 13 μm thickness were produced on Ni55 substrates by low temperature ion sulfurizing to reduce wear and tear to the Ni55 coatings. The Cu 2 S film is composed of polygonal micro-rods that were constructed from successive Cu 2 S nano-sheets with SEM. The antifriction effects of the film were conducted by ball-on-disk dry sliding tests using various loads and speeds under dry friction conditions. The results indicated that the Cu 2 S film showed enhanced antifriction performance by significantly reducing the friction coefficients and the depths of wear. With the help of copper particles formed by cuprous sulfide and oxygen, the Cu 2 S film is able to separate the friction pairs from each other. Also, coating them with the film can significantly reduce the wear and tear to composite coatings caused by the plowing action of debris from the Ni55 coatings. [ABSTRACT FROM AUTHOR]