Study of resistance performance of Al 2 O 3 -ZnO-Y 2 O 3 thermal control coating exposed to vacuum-ultraviolet irradiation.

As deep space exploration moves farther and farther away, thermal control coating of the in-orbit spacecraft will suffer a serious vacuum-ultraviolet radiation environment, which seriously threatens the reliability of the spacecraft in orbit. Therefore, it is important to improve the vacuum-ultraviolet resistance performance of the thermal control coating. In this work, the inorganic Al 2 O 3 -ZnO-Y 2 O 3 thermal control coating was in situ fabricated on a 6061 aluminum alloy surface by PEO technology, and its vacuum-ultraviolet resistance performance was investigated. The results show that the Al 2 O 3 -ZnO-Y 2 O 3 thermal control coating has a good resistance performance to vacuum-ultraviolet radiation, which is mainly because the large extinction coefficients of the ZnO and Y 2 O 3 materials in the ultraviolet band are conducive to improving the ultraviolet resistance performance. Furthermore, the life prediction model of the Al 2 O 3 -ZnO-Y 2 O 3 thermal control coating shows that its Δ α s value first slightly increases and then tends to be stable with the increase of ultraviolet irradiation time from 0 ESH to 25 000 ESH, and the maximum variation of Δ α s is about 0.0536. This work provides a material basis and technical support for the thermal control system of spacecraft with long life and high reliability.