High performance polymer for dust tolerant extreme environment bearings

In Phase I, we demonstrated ATSP-based coatings vs. ATSP-based coatings have excellent tribological performance: low coefficient of friction (COF) and ldquo;zero wearrdquo; in a widet emperature application range (from -196deg;C to 300deg;C). Additionally, for ATSP-based coatings, the 50-year equivalent low-earth-orbit proton exposure had no effect on its tribological performance. This excellent tribological performance leads us to introduce ATSP coatings for Lunarsrsquo; dusty abrasive conditions in combination with wide temperature changes. In Phase II, the ATSP composite coatings were compared with one of the state of the art (SOA) material, polyether ether ketone (PEEK) based polymer composite coatings for abrasive wear. The polymer-on-polymer system resulted in a 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 (lt;38 mu;m size) environment. ATSP coating showed higher resistance to abrasive wear than PEEK, and dust was more detrimental to tribological performance (i.e., friction and wear), particularly for PEEK coating. The Phase II Sequential proposal will utilize these capabilities and advance the TRL 3-4 to TRL 6-7 and a pathway to TRL 9. In addition to the rolling-sliding simulated test for bearing application, full scale bearings will be fabricated and tested in the simulated conditions and also will be tested using Harmonic drive, which is one the most important parts for the lunar rovers for actuation. At the end of Phase II-S, custom fabricated ATSP bearing will be handed over to NASA.