Effect of irradiation dose on the structure and tribological performance of Ti:WS 2 /PFPE composite lubricating system in atomic oxygen environment

ABSTRACTPFPE (Perfluoropolyether) oil possessing higher oxidation stability than hydrocarbon lubricant is combined with Ti:WS2 film to construct solid-liquid composite lubricating system. The results indicate that atomic oxygen (AO) irradiation generates some important effects for the Ti:WS2/PFPE composite lubricating system. With increase of irradiation dose, the molecule structure of PFPE oil occurs to carbon chain breakage and appears the obvious molecule cross-linking and polymerization. Meanwhile, Ti:WS2 film also is oxidized to different extent to form WO3. The changes in solid-liquid system resulted in the greatly different tribological properties of Ti:WS2/PFPE system. The friction coefficient of the system significantly increases in low-dose irradiation, while the value inversely sharply decreases in high-dose AO, which is related to the presence of WO3 and formed transfer film. Finally, the failure mechanism of Ti:WS2/PFPE system under AO irradiation was revealed.KEYWORDS: Solid-liquid lubricationPFPE oilAO irradiationTribological performanceFailure mechanismDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.