Effects of molybdenum disulfide shot treatment on electrical sliding current of a slip ring

In a commutator or a slip ring in a rotating electric device, sliding materials are worn by friction acting at their surfaces. Our research focuses on approaches to reduce this material wear. Selection of a lubricant that has good lubricity and low contact resistance characteristics is important. In this study, we examined molybdenum disulfide, which was coated onto the copper cylinder surface. An energization experiment was performed by bringing a copper pin sample into contact with the cylinder. There have been no previous reports on the sliding current at materials coated with molybdenum disulfide. Thus, we aimed to clarify the frictional and electric conduction characteristics of molybdenum disulfide. The coefficient of friction was reduced by half through coating the sliding surfaces with molybdenum disulfide, indicating a lubricating effect. In addition, the contact electric resistance was reduced by the effects of the lubricant. However, when the lubricant peeled off owing to sliding contact, adhesion occurred owing to sliding contact between the copper surfaces.