Abstract
The carbonaceous hard coating such as DLC (Diamond-Like Carbon) is one of the promising materials to prevent surface damage by its high hardness, and the material attracted us as a low friction material. It was reported that the Carbon Nitride (CNx) coating exhibited lower friction coefficient than other DLCs under oil lubrication. However, low friction mechanism of CNx in oil boundary lubrication has not been clarified. In order to clarify this mechanism, we conducted friction test by a pendulum style friction tester, which can measure friction coefficient under boundary lubrication clearly. As the result, it was confirmed that CNx showed lower friction than usual DLC and unusual sliding speed dependency of friction under the boundary lubrication. And analysis by ESR (Electron Spin Resonance) analysis showed that friction coefficient does not depend on dangling bond density.
