Vacuum tribotester with atomic oxygen simulation ability

A tribotester consisting of ball-on-disc friction tester, atomic oxygen (AO) source, and ultrahigh vacuum (UHV) unit was developed in order to study the tribological properties of solid lubricants in low earth orbit (LEO) environments. The apparatus has a lowest chamber pressure of 2.0×10^-7 Pa, a normal contact load of 1-10 N for a ball-on-disc point contact configuration, and a continuously adjustable disc rotational speed of 50-3000 r/min. The pilot test results show that the flux density of the atomic oxygen beam is as high as 3.0×10¹⁵ atoms/cm²·s, while the beam energy is as high as 1-10 eV at the chamber gas pressure of 10^-1-10^-3 Pa. The comparative evaluation of the friction and endurance of sputtered MoS₂ film and MoS₂-based composite films on the developed test rig and a CZM-1 vacuum friction and wear tester indicates that the developed apparatus has good reliability and reproducibility. It can be used to study the tribological properties and the failure mechanism of materials in LEO environments.