Tao Li,Hongjun Kang,Songtao Lu,Wei Qin,Xiaohong Wu
As space exploration moves further and further into deep space, it is a big challenge to develop antistatic inorganic thermal control coating with lightweight and strong adhesion to substrates. Herein, this work reported an inorganic antistatic AZO/Al 2 O 3 -ZnO-Y 2 O 3 composite coating fabricated by PEO combined with ALD methods. The results show that when the Zn/Al ratio of deposited AZO film is 24:1, its overall performance is the optimal, and the emissivity, absorptivity and resistivity are 0.892, 0.409 and 1.15 × 10 –3 Ω·cm, respectively, which can meet thermal control application requirements of spacecraft. Furthermore, the AZO/Al 2 O 3 -ZnO-Y 2 O 3 composite coating shows a good electron-resistance irradiation performance, which is because AZO conductive film is easy to generate free carriers, speed up some electron transport and make electrons better disperse and conduct, thus reducing the penetration depth of electron irradiation. This work provides a material basis for thermal control system of spacecraft with long life and high reliability.
Polyimide (PI), a high-performance polymer widely employed in aerospace applications due to its superior electrical insulation, processability, and long-term stability, faces operational challenges at vacuum-solid interfaces. Under extreme space conditions, vacuum flashover phenomena frequently occur at PI interfaces during spacecraft operation, critically jeopardizing the reliability of the onboard electronic components. This study demonstrates a molecular engineering strategy to suppress secondary electron emission and improve surface insulation by modulating trap states through strong electron-withdrawing groups. Two all-organic specialty PI films were systematically developed via a strategic molecular structure design and subsequently fabricated. These films incorporate strong electron-withdrawing groups (e.g., −SO2– and −CF3), which effectively enhance trap densities and deepen trap levels, thereby suppressing the secondary electron multiplication process. Both specialty PI films demonstrated significantly enhanced vacuum surface flashover thresholds, with their vacuum flashover voltages Uho increased by 12.65 and 17.08% compared to pristine PI, respectively. The proposed molecular design paradigm provides a fundamental advancement in dielectric materials engineering, addressing the critical need for high-voltage tolerant insulation systems in next-generation spacecraft requiring elevated operational power and extended mission durations.
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