The influence of the oxidation time on the optical properties of the ceramic thermal control coating prepared by micro-plasma oxidation

The ceramic thermal control coating was produced in situ growth on the aluminum alloy by microplasma oxidation method. The coating possessed stable optical properties, high microhardness, and excellent adhesive power, low cost and so on, which can be widely used in the thermal control system of the spacecraft. In this article, the influence of oxidation time on the solar absorptance and emittance of the coating had been studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the phase composition and microstructure of the coating. The results show that the coating that is mainly composed of the a-Al2O3 and c-Al2O3 phase has porous surface configurations. The coating can reach to a solar absorptance value higher than 0.91 and an infrared emittance value higher than 0.76, which can be used as a kind of important thermal control coating for space applications.