Improved Oxidation Stability of 1,3-Diketone Superlubricity Fluid Using a Butylated Hydroxytoluene Additive

As an oil-based superlubricity material on steel surfaces, 1,3-diketone fluid is promising for the friction reduction of mechanical devices. However, the unsaturation of its molecular structure would potentially cause the oxidation problem in industrial applications. In this study, the oxidation mechanism of diketone fluid 1-(4-ethyl phenyl) nonane-1,3-dione (EPND) was discovered through the accelerated oxidation experiment in an oven. By doping butylated hydroxytoluene (BHT) anti-oxidation additive at an optimal concentration of 0.5%, both the oxidation onset temperature (OOT) and oxidation induction time (OIT) of EPND could be enhanced to a comparable level of 4121 commercial oil, which is a fully-formulated lubricant with a similar viscosity to EPND. Moreover, the friction test verified that the incorporated BHT additive induced negligible influence on the superlubricity performance of EPND. The result of this study is helpful for improving the weakness of the diketone superlubricity system and promotes a further step in its practical applications.