高载荷条件下石墨-石墨摩擦副的摩擦学特性研究

利用研制的高载荷条件下摩擦因数测试装置,研究了石墨/石墨摩擦副在空气、水和油介质中的摩擦学特性。结果表明在4~15MPa范围内,随着载荷的增加,摩擦副在空气、水和油介质中的摩擦因数都逐渐降低;在油介质中摩擦副的摩擦因数最小,在水介质中摩擦因数变化最平稳,在空气中摩擦因数最大,且随载荷的增加变化幅度最大。磨损表面原始形貌对比分析表明,在空气中,摩擦副表面处于边界润滑状态,主要磨损机制是粘着磨损和犁削;水润滑条件下为轻微犁削;油润滑条件下,摩擦副表面处于为边界润滑和流体润滑状态,油中的减摩剂对试样表面有抛光作用。

Tribological Behavior of Self-mated Graphite Pair in Overload Conditions

The tribological behaviors of self-mated graphite pairs under air, water and oil-lubricated situations were comparatively studied with the self-designed friction tester. As a result, when the contact pressure range is 4 - 15 MPa, the static and the sliding friction coefficient of graphite pairs under all test situation decreases with the increasing of the load. The graphite has the largest friction coefficient in the air-lubricated condition ,while has the lowest in oil-lubrication. Under water-lubricated condition, the down trend of the friction coefficient of the graphite pairs is rather stable, which alters most sharply under air-lubricated environment. The wear mechanisms of the graphite pairs were examined based on the original image before and after sliding, the result shows that under air media, the graphite pairs works on the conditions of boundary lubrication and the wear mechanism is dominated by adhesion and plough wear, which is dominated by slightly plough wear under water environment. Under oil-lubricated sliding, the lubrication state is boundary and hydrodynamic lubrication. The friction modifiers polishing the surface of the friction pairs contributed to the low friction coefficient.