磁场环境中的Mo-W喷涂层摩擦磨损性能

Friction and Wear Properties of Mo-W Spraying Coating in Magnetic Field

采用超音速等离子喷涂技术在45CrNiMoVA钢表面制备了Mo-W合金涂层,并与6061铝合金组成摩擦副,进行了磁场环境下的摩擦磨损试验。通过场发射扫描电镜(SEM)、电子能谱仪(EDS)分析涂层组织;采用X射线衍射仪分析涂层相组成;在不同磁感应强度(B)下测试了涂层显微硬度、表面氧浓度和表面温度。结果表明:随着磁感应强度的增加,Mo-W涂层的摩擦因数降低,磨损量有小幅减小。摩擦副表面的温度比不加磁场时有10~20℃的温升。磁场的施加对Mo-W涂层显微硬度值不会造成影响。Mo-W涂层磨损表面的氧含量随B的增加而变大。磨屑主要由表面覆有Al_2O_3的Mo-W合金微粒和Al_2O_3微粒组成,磨屑粒径随着B的增加逐渐变小。磁场在Mo-W涂层与6061铝合金的摩擦中主要有两个作用:一是提高摩擦副间的氧浓度,促进氧化磨损;二是使磨粒细化,降低摩擦因数。

Mo-W alloy coating was prepared on steel 45 CrNiMoVA by supersonic plasma spraying technology, which formed the friction pairs with 6061 aluminum alloy. Friction and wear tests in magnetic field were studied on the friction pairs. The coating structure was analyzed by SEM and EDS, while the phase constituent of the coating was tested by X-ray diffractometer. The surface oxygen concentration and surface temperature were tested in different magnetic induction（B）. The results show that with the increase of B, the friction coefficient of the Mo-W coating is reduced and the wear volume is slightly decreased. The friction surface temperature in magnetic field is 10 to 20 ℃ higher than that without magnetic field. The addition of magnetic field has no obvious effect on the microhardness of the Mo-W coating. The oxygen content of the worn Mo-W coating surface increases with the increase of B. The debris is mainly composed of Al2O3 particles and Mo-W alloy particles covered with Al2O3, and the particle size decreases gradually with the increase of B. There are two main roles of magnetic field in the friction the of the Mo-W coating with 6061 aluminum alloy, one is to increase the oxygen concentration between the friction pairs and then promote the oxidation wear phenomenon; the other is to refine the abrasive particles and reduce the friction coefficient.