Effects of atomic oxygen exposure on the tribological performance of ZrO2-reinforced polyimide nanocomposites for low earth orbit space applications

The effects of atomic oxygen exposure on pure polyimide and nano-ZrO₂ reinforced polyimide composites were investigated in a ground-based simulation facility. The experimental results indicated that the surface structure of both pure polyimide and ZrO₂/polyimide composites were destroyed by atomic oxygen attack, but the addition of nano-ZrO₂ particles in polyimide could obviously decrease the mass loss, which showed that ZrO₂ could enhance the atomic oxygen resistance. The results of ZrO₂/polyimide composites before and after atomic oxygen exposure showed that atomic oxygen irradiation aggravated the friction and wear of the ZrO₂/polyimide composites. The wear mechanism was mainly abrasive particles wear arising from the ZrO₂-rich layer on the surface of composites. The ZrO₂/polyimide composites with 1 wt% nano-ZrO₂ owns the lowest varying rate of the friction coefficient and wear rate before and after atomic oxygen exposure, which showed stable friction and wear properties and was expected to become a kind of potential tribological materials for practical spacecraft designation.