Abstract:Through simulating the operating condition of aviation engine by the high temperature and high pressure autoclave,the change rule of the physicchemical properties of the oil samples mixed by polyαolefin base oil and antioxidants of 2,6ditertbutyl4methylphenol and p,p’diisooctyl diphenylamine was studied at different temperature.The oxidation mechanism of PAO aviation lubricating oil was studied using a variety of modern analytical methods,and the oxidized products at high temperature were analyzed.The results show that a large number of low molecule compounds are produced in the aviation lubricating oil with the increasing of temperature,which results in the viscosity reduction and acid value increasing.The antioxidants slows down the attenuation process of viscosity significantly,and inhibits formation of small molecular alkanes and olefins.The thermal oxidation of the oil samples follows a radical reaction mechanism.