Tribological Characteristics of MoS_2 Film under Oil,Grease Lubrication and Dry Sliding

To investigate the tribological performance of MoS2 film under dry friction,and lubrication of different lubricants,experiments on the steel /MoS2 and steel/steel tribo-couples on a ball-on-disk tribo-tester were carried out.The effect of lubrication,load and speed to the friction coefficient were analyzed.The surface morphology of MoS2 film investigated by atomic force microscopy(AFM)was used to study the effect of the lubrication conditions on the wear rate.The results indicated that the friction coefficients of the MoS2 film lubricated with 4122 oil and FAG grease were much lower than that under dry sliding.In addition,At the start-up and under boundary lubrication,the MoS2 film could reduce the friction effectively;On the other hand,liquid lubrication causes a dramatic decrease of the wear ability of the MoS2 coatings,the wear rate of the MoS2 dry-film is about 4.4×10-8 mm3/(N·m),superior to which work under oil and grease lubrication(about 1.9×10-6 mm3/(N·m)and 4.1×10-7 mm3/(N·m),respectively).