Optimization for Industrial Applications by Mechanical Properties and Reducing Static/Dynamic Friction Coefficient of DLC Coatings

抄録

DLC (Diamond-Like-Carbon) providing a useful low friction coefficient, is especially suitable for various drive-line applications including automobile parts, but the value of this friction coefficient is often determined under a constant speed sliding environment. However, many of the sliding parts do not always operate at constant speed, hence it is necessary to consider motion from a stationary state. In this study, the effects of mechanical properties (hardness), varied by modification of each film structure, on static/dynamic friction coefficients were evaluated for DLC deposited by plasma-CVD and arc-PVD. A thrust cylinder type friction wear tester was used to measure each friction coefficient. The maximum frictional force at the initial stage of rotation was calculated to give the static friction coefficient, and the friction coefficient at a constant peripheral speed was defined as the dynamic friction force. From the results, satisfactory low coefficients of friction and a reduction in static friction force proved that DLC coating is useful for treatment of sliding parts in drive mechanisms. Furthermore, the film structure and mechanical properties of DLC have a large effect on static/dynamic frictional forces, and the study indicates the need to select the optimum DLC according to the application and expected sliding environment.