Abrasive wear of PEEK and ATSP-based polymer composite coatings under lunar regolith conditions

Abrasive wear of polyether ether ketone (PEEK) and aromatic thermosetting co-polyester (ATSP) based polymer composite coatings were examined with lunar regolith simulant environment by conducting pin-on-disk experiments under dry sliding conditions, contact pressure of 17.5 MPa, and sliding speed of 0.25 m/s. Three different tribo-interfaces, namely metal-on-metal, metal-on-polymer, and polymer-on-polymer were designed to evaluate the efficacy of each polymer coating on the friction and wear improvement, as well as the extent of sand-dust mitigation at the interface. The polymer-on-polymer system resulted in significant reduction in friction up to 70%. The wear mechanism was a mixed mode of two-body and three-body abrasion for metal-on-metal and metal-on-polymer tribopairs, while the polymer-on-polymer tribopair significantly mitigated the sand and dust accumulation at the interface with three-body abrasion as the dominant wear. Both polymer composites showed similar frictional behavior, while ATSP composite showed superior abrasive wear resistance, particularly under small size dust (<38 μm size) environment.