Research On The Tribological Characteristics Of Polyimide Friction Pair Under Water Lubrication

Water hydraulic technology, with its not easy to burn, green environmental protection and other advantages, plays a more and more important role in the field of hydraulic transmission and control. However, the basic research of water hydraulic components is not enough. The tribology performance of Hydraulic components friction pair is an important subject.Polyimide(PI) materials with excellent mechanical properties, lubricating and processing performance, especially the high temperature resistant performance, shows great potential in the field of tribology. Although the tribological properties of PI have been studied under dry friction condition in recent years, research is very lacked under water lubrication condition. This article carries on the tribological performance of PI friction pair under water lubrication from the factors of material proportioning, metal materials, process methods and structure of friction pair.This article studies tribological performance of friction pair with PI in the water environment by the friction and wear testing machine of MMU-10 F. The contact type of friction pair is surface contact of ring to ring. The studies indicate that the effect of PTFE on improving the tribological properties of polyimide materials is not obvious under water lubrication. Gr can improve the friction performance of PI material, but the improvement effect on wear performance is limited. While the reinforced PI material by CF has good tribological properties. According to above experimental research, the friction pair between PI with 30%CF and nitriding 17Cr16Ni2 can get the best tribological properties among the experimental friction pairs. The study on forming process indicates that compression moulding and injection moulding have little different effect on the tribological properties of the friction pair. Then the environmental scanning electron microscope is adopted to observe the surface microstructure, which indicates that matched with quenching 17Cr16Ni2, wear mechanism of PI with 30%CF is extrusion spalling caused by abrasive wear, that of PI with 15%CF+15%Gr is layered peeling caused by adhesive wear.In order to improve the heat dissipation performance of PI friction pair, this paper designs 3 kinds of low temperature thermal equilibrium structures to make finite element analysis, which shows that structure2 with three grooves can be used as the optimal low temperature thermal equilibrium structure among the three structures. This result is also verified by the experiment. The tribology experiment indicates that the friction pair with low temperature thermal equilibrium structure can run more steadily compared with the original friction pair. The friction coefficient and wear rate are smaller. This is resulted from two reasons. On one hand, the surface of the friction pair has good cooling conditions. On the other hand, the abrasive dust can be discharged quickly from the friction pair, which avoids three-body abrasive wear. This research is of great significance for the design of friction pair structure of hydraulic pump with high polymer materials.