One of the most widely utilized and well-established atomic oxygen (AO) protection solutions for LEO satellites is the deposition of protective coatings on polymeric materials. However, manufacturing extensive expanses of coating materials with good transparency, flexibility, smoothness, ultra-thinness, and exceptional AO resistance remains a critical issue. Herein, we successfully deposited a 400 nm thick polyorgansiloxane (SiOxCyHz) coating with high optical transparency and uniform good adherence on a 1.2 m wide polyimide surface by optimizing the distribution of hexamethyldisiloxane and oxygen as precursors in the roll-to-roll compatible plasma-enhanced chemical vapor deposition process. After AO irradiation with the fluence of 7.9 × 1020 atoms cm–2, the erosion yield of the SiOxCyHz -coated Kapton was less than 2.30 × 10–26 cm3 atom–1, which was less than 0.77% of that of the Kapton. It indicates that the SiOxCyHz coating can well prevent the erosion of Kapton by AO. In addition, it was also clarified that a SiO2 passivation layer was formed on the surface of the SiOxCyHz coating during AO irradiation, which exhibited a “self-reinforcing” defense mechanism. The entire preparation process of the SiOxCyHz coating was highly efficient and low-cost, and it has shown great application potential in LEO.
The atomic structure, interface stability and electronic interaction of TaB2(0001)/SiC(111) interfaces were investigated by first principles study. The study found that the termination atom and stacking position are the key factors affecting the bonding strength and stability of the interface. On the basis of considering work of adhesion (Wad) and interfacial energy (γint), the Ta-TaB2/C-SiC centre-site stacked (Ta CS-C) and B-TaB2/C-SiC center-site stacked (B-CS-C) configurations were recognized as the most stable structures from ten different interface models. Electronic interaction of the two most stable interfaces were revealed by analyzing the charge density distribution, charge density difference and partial density of states (PDOS), and it was found that ionic and metallic bond coexisted in Ta CS-C interface, while covalent bond played a dominant role in B-CS-C interface.
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