The influence of proton radiation on the friction and wear of Ti:WS2/P201 composite lubricating materials for space application

The effects of proton radiation (PR) irradiation on the components, friction and wear of Ti:WS2/P201 composite lubricating system were mainly investigated. PR irradiation has a great effect on the physicochemical properties of P201 oil, which can not only decompose oil into small molecular but also make it cross-linking and polymerization. More seriously, oil layer with good wettability transfers to a solid-like organic film on sample surfaces after PR irradiation. In addition, PR irradiation has a slight effect on the microstructure of Ti:WS2 film due to coverage of oil layer. Meanwhile, Ti:WS2/P201 system obviously increases the friction coefficient and wear rate, especially extremely shortened life at high irradiation dose. It attributes to P201 oil occurred degradation when suffers from high PR energy, forming polymer with higher molecular weight. The polymer has poor replenishment on sliding contact interface, so destroying endurance of transfer film, which deteriorates the component and property of the system. At the high irradiation dose, the oil nearly loss fluidity, causing severe abrasive wear and tribo-oxidation, further accelerating the failure of the solid-oil materials.