Differences in Wear Tongue Development: Thermal Degrade Effect on the Tribological Behavior of FKM O-Ring Seals

Due to thermal degradation, the tribological performance of fluororubber (FKM) at high temperature is not satisfactory, despite its excellent temperature resistance. In this paper, the friction and wear process of FKM O-rings were traced by the tribo-test, which compares the wear behaviors at different stages of the wear process. Results showed that under the influence of thermal degradation of FKM, the wear rate and friction coefficient decrease, while the friction instability increases. This phenomenon is caused by the deterioration of the mechanical properties affects the development of the typical wear pattern of FKM in unsteady state (running-in stage). The wear debris is more likely to adhere to the surface of the wear scar, which causes the friction form to change from two-body abrasion to three-body abrasion. Findings from this study can enhance understanding of tribology behaviors of FKM O-ring seals under the high temperature condition and can help develop higher-performance alternatives.