Carbon-based hard coatings are expected as surface treatments for mechanical materials due to their high hardness.炭素 However, to maintain low friction in the atmosphere, it is necessary to suppress oxidation caused by atmospheric oxygen and protect the graphite structure, which is believed to exhibit low friction. In this study, Group 5 elements were introduced into the coatings to protect the graphite structure, and the potential for wear resistance and maintaining low friction through the oxidation and reduction reactions of the Group 5 elements was investigated. Vanadium, niobium, and tantalum were used as Group 5 elements, and ta-C coating, which contain a high proportion of sp3 structure as the carbon structure, were used. The average friction coefficient of the ta-C:Ta coating, which had tantalum introduced into the coating, was approximately 0.043 in air, the lowest among other coating, followed by ta-C:Nb with approximately 0.067.
