The contact interface between the bearing shells and crankshafts in marine internal combustion engines is subjected to complex forces during operation,and improper lubrication can easily cause adhesion,scratches and cracks on the journal.To extend the service life of bearing shells,the polyamide imide and polytetrafluoroethylene (PAI/PTFE) composite coatings were prepared on the surface of bearing shells,and the effect of MoS2 particles on the friction performance of PAI/PTFE composite coatings was explored.Composite coatings with different MoS2 mass fraction were prepared on the surface of Al-Sn-Cu alloy bearing material by spray-sintering method.Using bearing steel ball as friction pair,the tribological properties of the composite coatings were investigated at 3 N,4 N,and 5 N loads under dry friction and oil lubrication.The results show that under dry friction,the friction coefficient of the composite coating with a MoS2 mass fraction of 2% is reduced by more than 80%,and the wear is reduced by more than 90%.The maximum reduction in friction coefficient under oil lubrication is 67%.The results of SEM and EDS analysis indicate that a coating containing 2% MoS2 will generate a uniform sulfide layer on the contact surface of the steel ball,which can protect the coating and improve its stability.By comparing the friction coefficient,wear,and wear scar morphology of coatings with different MoS2 content,the optimal ratio of the coatings is obtained.It is shown that an appropriate amount of MoS2 can improve the stability of the coating friction film and reduce friction and wear.