热压Ni－MoS_2自润滑复合材料在不同温度的往复摩擦磨损特性

FRICTION AND WEAR BEHAVIOURS OF HOT-PRESSED Ni-MoS_2 SELF-LUBRICATING COMPOSITES IN RECIPROCATING SLIDING AT DIFFERENT TEMPERATURES

采用自润滑复合材料，对提高某些机械摩擦副的使用寿命有很显著的效果。研究了热压Ｎｉ－ＭｏＳ_２自润滑复合材料与ＧＣｒ１５钢球组成的点接触配对副，在室温和高温条件下进行微幅往复摩擦运动时的自润滑特性。考察了载荷、温度及ＭｏＳ_２含量对摩擦系数和磨损率的影响，并借助扫描电镜观察磨损表面的形貌特征。结果表明：摩擦系数随载荷增加而不断提高；温度在４００℃以下时，摩擦系数能保持较低数值；在室温和２５０℃时，含６０％ＭｏＳ_２的复合材料均具有最低磨损率；提高ＭｏＳ_２含量有助于改善高温自润滑性；ＭｏＳ_２转移润滑膜的完整程度可作为Ｎｉ－ＭｏＳ_２复合材料自润滑性能好坏的判据。

Self-lubricating composites are very effective for increasing the service life of friction pairs in some machines.This paper deals with the self-lubricating properties of hot-pressed Ni-MoS_2 composites in air at room tempetarure and elevated temperatures,when they are frictionally coupled with reciprocating sliding ball of GCr15 bearing steel.The effects of load, temperature and MoS_2 content on friction coefficient and wear rate have been investigated respectively.The morphologies of wear tracks have been examined under scanning electron microscope (SEM). The results show that the friction coefficient increases continuously with the increasing of load, and can be kept at lower level until the temperature is elevated to 400℃ the composite containing 60% MoS_2 possesses the lowest wear rate at both room temperature and 250℃. The increase of MoS_2 content is beneficial to improving the high temperature self-lubricating property of the composites. It is suggested that the homogenity and integrity of MoS_2 transfer film formed on the frictional surfaces can be as the evaluation criterion of the self-lubricating property of Ni-Mo S_2 composites.