Investigation of Tribological Properties of Different Slipper/Swashplate Pair Materials under Start-Stop Operating Conditions

The material properties of friction and wear behavior of copper/steel bimetallic self-lubricating materials prepared by powder metallurgy were analyzed under multiple operating conditions and compared with traditional cast self-lubricating materials bronze (CuSn10) and brass (Cu62Zn). The results indicate that the bimetallic samples exhibit the lowest friction coefficient during the mixed lubrication stage, and transition to the elastohydrodynamic lubrication (EHL) stage more rapidly. Under dry friction with fixed speed and load, bimetallic materials exhibited the most stable friction coefficient and a reduction in wear volume of nearly five times compared to other copper alloys. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analyses indicated that the predominant forms of wear observed in the bimetallic samples were plastic deformation, shallow furrow wear, and slight adhesive wear. In contrast, CuSn10 samples exhibited a clear tendency toward abrasive wear, accompanied by a certain degree of oxidation wear. The wear behavior of the Cu62Zn samples was mainly characterized by abrasive wear and substrate surface peeling. Under stepwise loading condition, the bimetallic samples exhibited better load-bearing and wear resistance. The wear volume of Cu62Zn was the largest, approximately 16.4 times that of the bimetallic samples, with wear mainly characterized by matrix flaking and abrasive wear. Under start-stop conditions, the bimetallic samples showed excellent wear resistance.