ANALYSIS OF TRIBOLOGICAL PROPERTIES OF SELECTED PTFE-BASED POLYMER COMPOSITES IN A SLIDING INTERACTION WITH ALUMINIUM OXIDE (Al2O3)

Abstract

The paper presents the microstructure and mechanical and tribological properties of polymer composites based on polytetrafluoroethylene (PTFE) intended for use in friction couples where reciprocating motion is performed, e.g., in compressors or actuators. Micromechanical tests carried out using the Oliver-Pharr method showed that the PTFE composite with a 40% bronze content (T8B) had the most advantageous mechanical properties (hardness H, Young’s modulus E). In turn, tribological tests that were conducted using a ballon- disc tester in the linear (reciprocating) motion showed that the polytetrafluoroethylene composite with a mixture of 25% bronze powder and 15% graphite (T4GM) had the lowest tribological wear. The tribological properties of composite T5W with 25% graphite content were not much worse. Despite the most favourable mechanical parameters, the tribological wear of composites T8B and PTFE with glassy carbon (T3Ws) was nearly twice higher due to the absence of grease formed by a graphite filling. The results show that the use of composites containing a bronze-graphite filling improves the service life of lubricant-free friction couples that perform reciprocating motion.