A novel PBO/PTFE-PI@M50 tribo-pair system: Achieving superior tribological performance under high-temperature extreme conditions

Self-lubricating fabric composites significantly enhance the tribological performance of joint bearings by minimizing friction and wear on both inner and outer rings, thereby substantially extending their operational lifespan. These characteristics make them excellent candidates for bearing liner materials. However, conventional PTFE/Nomex phenolic-based fabric composites exhibit limitations in high-temperature environments, necessitating the development of more thermally stable alternatives. To address this challenge, this study introduced a novel PBO/PTFE polyimide (PI)-based self-lubricating fabric composite and proposed a PBO/PTFE-PI@M50 tribo-pair system suitable for high-temperature working conditions, utilizing M50 bearing steel as the counterpart material. Compared to Nomex fiber-reinforced self-lubricating fabric composites, PBO/PTFE-40PI (fabric composites with resin mass fraction of 40%) demonstrated significantly superior high-strength and high-temperature tribological performance. Notably, even at 300℃, it maintained an elastic modulus of approximately 15 GPa and a tensile strength of around 335 MPa, while achieving a low friction coefficient of 0.023 and an impressively low wear rate of 0.83×10^-6mm³/(N·m). The superior properties of PBO/PTFE-PI@M50 tribo-pair system stemmed from the composite's exceptional heat resistance and mechanical stability at high temperatures. Under the combined effects of the 'thermal-mechanical-chemical' interactions, the fiber-reinforced composite material formed a dense, uniform, and strongly stable transfer film on the surface of the M50 steel ring. Detailed analysis revealed that the film's stability primarily arose from the viscoelastic transition of PI and PTFE under high temperature, coupled with their strong tribo-chemical reactions with the steel ring. Given its outstanding performance, the PBO/PTFE-PI@M50 tribo-pair system holds considerable promise for advanced engineering applications.