境界潤滑下における ZDDP の潤滑性に及ぼすイオン液体添加の影響

抄録

Zinc dialkyldithiophosphate (ZDDP) is a multifunctional additive that improves anti-oxidation, anti-wear, and anti-seizure properties of lubricants. However, there is a demand to reduce the concentration of ZDDP in lubricants as it is also responsible for catalyst poisoning, generation of sludge, and corrosion of copper-based alloy components. Ionic liquids (ILs) are recently expected as new lubricant additives that improve friction and wear properties. In this study, both ZDDP and ILs were used as lubricant additives in order to reduce the concentration of ZDDP and improve the tribological performance of a steel/steel tribopair under boundary lubrication. the results showed mixed solutions of ZDDP and ILs exhibited lower friction and higher wear resistance compared to the case of the ZDDP only added solution. From the result of surface analyses, there were differences between the chemical composition and film thickness of tribofilms on the worn surfaces. All our experimetssuggest that the formation of ZDDP and ILs mixed tribofilms contributed to the improvement of the tribological performance under boundary lubrication.