Wear reduction effect by applying DLC to sliding components of air-conditioning compressor

DLC (Diamond-Like Carbon) has excellent tribological properties such as high hardness, low friction and high wear resistance. It is widely applied in industrial field. In order to prevent excessive wear, DLC is also applied to the vane which is the main sliding component of the compressor for air conditioning. In this study, we investigated the wear reduction effect on sliding surface between the DLC vane and the compressor roller which is made of cast iron. As a result, the DLC vane can reduce the wear of the surface of roller compared to a nitriding vane. And it is found that carbon film is formed on sliding surface of the roller in the case of using DLC vane. This carbon film does not have the structure of DLC but the structure of glassy like carbon. We consider that this carbon film is generated from the graphite composition of the roller by friction heat and it contributes to the wear reduction of roller. Furthermore, we carried out experiments using rollers containing different content ratios of graphite on the surface, and confirmed that the same wear reduction effect exists owing to the carbon film.