Effect of Thermal Degradation of FKM on Three-Body Abrasion under Dry Sliding: Severe Damage Led by the Particle Detention

Both the high temperature and particle environment at the downhole greatly aggravate the abrasive wear and shorten the service life of the fluororubber (FKM) seal seriously in drilling engineering. At present, there is less awareness of the tribological behavior of seals in such complex working conditions. In this work, the abrasive wear performance of the thermally degraded FKM seal was tested in the form of simulating the intrusion of abrasive particles into the interface. Results show that the wear of both rubber seals and metal counterparts is exacerbated. Through the analysis of the wear scar morphology and friction coefficient, it is revealed that more abrasive caves scatter on the surface due to the mechanical degradation of the FKM. These abrasion caves reduce the tendency of particles to escape from the caves and prolong the abrasive action. Furthermore, the abrasion cave alters the particle motion from sliding to rolling, which leads to more caves generated on the surface of the hard tribo-pair. These results enhance the understanding of the abrasive wear for FKM seals and hopefully contribute to the promotion of seals used in hot abrasive particle environments.