RESUMO
In order to explore the influence of space ultraviolet radiation on spacecraft lubricating materials, an in-situ friction experimental device simulating space ultraviolet radiation was developed in the laboratory, and the experimental verification was carried out. This paper firstly introduced the design index, structure and working principle of the space ultraviolet irradiation simulation device, and then calibrated and tested the parameters of the whole device, and also conducted a virtual operation of the device's operation effect by simulation software, and the results showed that it met the design index. Finally, the validation tested of the ultraviolet irradiated in-situ friction experimental device were described in detail. By using the device to irradiate the samples, it was found that the in-situ ultraviolet irradiation device could achieve the expected irradiation effect, and the irradiation would lead to changes in the surface structure and properties of the PTFE material, while also achieving the need for in-situ spatial friction property testing of the material, providing favorable conditions for future testing.
RESUMO
To investigate atomic oxygen effects on tribological properties of Mo/MoS2-Pb-PbS film and further enlarge application range, atomic oxygen exposure tests were carried out for 5 h, 10 h, 15 h, and 20 h by the atomic oxygen simulator with atomic oxygen flux of 2.5 × 1015 atoms/cm2·s. The exposure time in test was equivalent to the atomic oxygen cumulative flux for 159.25 h, 318.5 h, 477.75 h, and 637 h at the height of 400 km in space. Then, the vacuum friction test of Mo/MoS2-Pb-PbS thin film was performed under the 6 N load and 100 r/min. By SEM, TEM, and XPS analysis of the surface of the film after atomic oxygen erosion, it was observed that atomic oxygen could cause serious oxidation on the surface of Mo/MoS2-Pb-PbS film, and the contents of MoS2, PbS, and Pb, which were lubricating components, were significantly reduced, and oxides were generated. From AES analysis and the variation in the main element content, Mo/MoS2-Pb-PbS thin film showed self-protection ability in an atomic oxygen environment. Hard oxide generated after atomic oxygen erosion such as MoO3 and Pb3O4 could cause the friction coefficient slight fluctuations, but the average friction coefficient was in a stable state.
