| In recent years,with the development of space stations and long-life satellites,in low earth orbit(LEO)environment,plasma discharge may occur in the polyimide(PI)film region between the cells in the solar array.At this time,if PI film eroded by atomic oxygen(AO)is broken down,it will lead to a secondary discharge,which will be disastrous.Therefore,it is imminent to research AO protection technology of battery array that can be used for engineering implementation.In this paper,application research is carried out on the AO protection of PI used in substrates,wires and cables of solar cell arrays.The research contents include the preparation of high-silicon oxide coating for wire and cable,protection of PI insulating layers on structures,and the adhesion method of PI film to the conductive structure and battery.Engineering protective technologies for AO on PI surface in space solar cell array is explored.The main researchs are as follows:(1)Preparation of high silicon oxide coatings on PI surface:Silicon-fluorine composite coating was prepared on the modified PI surface by high silicon content(silicon dioxide)solution and fluorine-containing compounds.The results show that when the concentration of silicon dioxide is 1 mg/m L,the optical properties of the sample remain good;when the concentration of silicon dioxide is 1.5 mg/m L,the mechanical properties of the sample are kept well,and the fluorinated coating has a good waterproof effect.This method is suitable for field construction and can be used to protect PI of wire and cable in solar cell array.(2)Preparation of organic-inorganic silica hybrid coating by template method:Silicon-containing coating solutions were prepared in soft templates formed by different types of surfactants(cetyltrimethylammonium(CTAB),nonionic surfactant F127 and P123),and organic-inorganic silica hybrid coating were prepared on modified PI substrate.The results of AO irradiation showed that the erosion rate of AO decreased from 3.26×10-24 cm~3/atom to 0.391×10-24 cm~3/atom after AO irradiation with cumulative flux of 3.24×1020atom/cm~2.The addition of surfactants made the microstructure of the composite coating more orderly and improved the interfacial adhesion between the coating and PI matrix.The hybrid coatings containing F127 had the best comprehensive performance,and the coatings did not crack and fall off,which help to improve PI's erosion resistance to AO.(3)In situ growth of POSS layer on PI surface and composite of Si O2 sputtering layer:The modified PI substrates were placed in the?-aminopropyl triethoxysilane(APTES)solution to grow the POSS transition layer,and then the Si O2 layer was magnetron sputtered.The results showed that the composite coating had excellent AO protection performance,the erosion rate of coating was only 0.19×10-24 cm~3/atom,and the optical property was good.(4)Study on adhesive bonding between PI and the metal substrates:The surfaces of PI film and titanium foil were modified with APTES,and both were hot-pressed at 20 MPa and kept at 120°C for 1 h.The results showed that the maximum tensile shear strength of the composite reached 46.2 MPa.The carboxyl group on PI film surface formed an amide bond with the amino group of APTES,and the Si-O-Ti bond was formed by dehydration condensation of the hydroxyl group of APTES and the hydroxyl group on the surface of titanium foil.This method has a certain study significance on the adhesion of the PI and the metal interface. |
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