In this study, the wear failure behaviour of coated self-lubricating spherical plain bearings under different working conditions in the light-load and low-frequency range was studied using a swing wear life tester. The commercial GE17ES bearing was the main research object, and the wear state of the bearing was monitored in real time using torque and temperature rise signals. Furthermore, a scanning electron microscope and an energy dispersive X-ray spectroscope were adopted to analyse the wear failure mechanism of bearings. The results indicated that the friction torque and temperature rise signal changes were mainly divided into three stages, and the characteristics of similar changes could be maintained under different working conditions. Furthermore, at the end of the bearing life, the torque and temperature rise had abrupt changes almost at the same time, which indicated the occurrence of bearing failure. In general, the wear failure mechanisms of bearings included abrasive wear and adhesive wear. Moreover, fatigue wear and oxidation wear were under some conditions. The torque and temperature rise comprehensively reflected the service state of coated self-lubricating spherical plain bearings, which could be used as a physical criterion for determining bearing failure. These results had a strong prospect of engineering application, and were expected to provide a reference for determining the failure behaviour of multi-type coated self-lubricating spherical plain bearings in the future, and provided theoretical support for establishing relevant test standards.

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To investigate ultraviolet (UV) radiation effects on tribological properties of Mo/MoS2-Pb-PbS film, ultraviolet (UV) radiation exposure tests were carried out for 20 h, 40 h, 60 h and 80 h by space UV radiation simulation device developed by our team, which can reach 3 UV radiation intensity. The exposure time in test was equivalent to the radiation of 100 h, 200 h, 300 h and 400 h in the space. Then, the vacuum friction test of Mo/MoS2-Pb-PbS thin film was performed under the 6 N load and 100 r/min, and friction test time of each sample was 20 min. By SEM, TEM, XPS the composition and morphology of Mo/MoS2-Pb-PbS film surface after UV radiation were analyzed. UV radiation could change the microstructure significantly and relative content of S element and MoS2 on the surface of the films decreased, and light mass loss of the films occurred. The tribological properties will also recover with the increase of sliding time, although the friction coefficient fluctuation of the film increased at the starting stage of the friction test. The damage of Mo/MoS2-Pb-PbS under UV irradiation was mainly caused by the volatilization of the enriched S element in the surface layer due to the high temperature heating of UV irradiation.

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