Property of Protection against Simultaneous Action between Atomic Oxygen Erosion and Ultraviolet Irradiation by MIL-53(Al) Coating

Rapid development of coatings with resistance to the space irradiation environment of low Earth orbit (LEO), which benefits long-duration exploration missions in LEO, improves the challenging urgency of revealing the interaction between atomic oxygen (AO) erosion and ultraviolet (UV) irradiation. Here, we investigated the simultaneous action of AO erosion and UV irradiation using polyimide (PI) and MIL-53(Al)-coated PI, confirming a synergistic enhancement effect of 21.20 and 14.96% compared to that of AO erosion alone. The resistance to simultaneous action was verified by a more stable chemical state and lower erosion yield (E_y = 4.386 × 10^–25 cm³/atom, 12% of pristine PI). Through first-principles calculations, the resistance processes to AO erosion and UV irradiation involve the formation of inert oxides, maintaining an unchanged framework and widening the band gap due to microstructure transformation, respectively. Based on these, simultaneous action resistance was explained, in which the boundaries between nanoparticle generation during UV irradiation provided a pathway for AO erosion and probability for collision with the framework to reduce the kinetic energy of AO. This work puts forward the novel investigation of simultaneous action in LEO, confirms the application potential of MIL-53(Al), and offers a new idea to protect the spacecraft.