振子型油性摩擦試験機における炭素系硬質薄膜の油中の摩擦係数速度依存性の評価

抄録

The carbon-based hard thin coating such as Diamond-Like Carbon is one of the materials to prevent surface damage. It was reported that Carbon Nitride （CNx） coatings showed lower friction coefficient than any other DLC coating when it slid in lubricated environment of PAO. But the mechanism of CNx's lower friction coefficient is not clarified. In this study, we clarify the relationship between sliding speed and friction coefficient of CNx thin coatings under boundary oil lubrication. We experimented pendulum-type test in lubricated conditions and observed motion of pendulum to know friction by high speed camera. The friction coefficient of CNx coatings increased with the increasing of friction speed at under 0.2 mm/s and decreased at over 0.2 mm/s. But in case of SUJ2 or tetrahedral amorphous Carbon（ta-C）coatings, they decreased or were constant at under 0.2 mm/s. From the results, it was suggested that CNx coatings performed like fluid lubrication while the others performed boundary lubrication.