Study on Anti-friction Film of Spherical Steel Bearing for Low Temperatue Environment with Low Friction Coefficient

To meet the reliable operation of a certain type of testing equipment in extreme environments −163 ℃ and under high load 150 kN, the friction coefficient of a kind spherical steel support is required to be less than 0.15. The spherical steel bearing with a low friction coefficient which is suitable for liquid nitrogen temperature is developed, which is made of stainless steel S03, and the split type design of ball joint bearings can greatly improve its suitability. The upper plane of the spherical steel shaft head is stressed to ensure that it serves as the main load-bearing component, while the ball screw only serves as a connecting component. The two parts of the friction pair are respectively coated with diamond-like carbon film and MoS₂ to reduce friction. Diamond like film of part is prepared by FLEXICOAT 850, and MoS₂ film is prepared by TEER CF-800. The SEM image of the cross-sectional morphology of the diamond-like carbon film shows that the film has a smooth and dense cross-sectional structure without obvious defects, and the film exhibits columnar growth.The SEM image of the cross-sectional morphology of the molybdenum disulfide based film shows that the molybdenum MoS₂ film is uniformly dense, which will be beneficial for improving the wear resistance of the component surface in atmospheric environments. Through the sample test, it has been found that the sliding friction pair has good reliability with the friction fatigue times exceeding 2 000 times and good friction characteristics with the friction coefficient as low as 0.098 under low temperature at liquid nitrogen .