Abstract:The oxidation tests of a certain type of domestic aviation lubricating oil and a imported ester aviation lubricating oil were carried out in the high temperature simulation oxidation device under the oxidation temperature from 175 ℃ to 290 ℃,to study the antifoaming property of lubricating oil under high temperature and pressure.The kinematic viscosity at 100 ℃ and acid value of the oil samples after oxidation at different temperature were measured,the oxidation component and main product were analyzed by using GC/MS,and the high temperature oxidation bubble characteristics and air release value were determined.The results show that the viscosity of two kinds of aviation lubricating oils is first increased and then decreased with the increase of oxidation temperature,and it reaches the maximum at 250 ℃.The viscosity of the imported oil is more stable due to the existence of polar intermolecular forces.The acid value of imported oil is increased sharply at high temperature due to hydrolysis and thermal oxidation when the oxidation temperature is too high,so its corrosion is worse than that of domestic oil.The foaming tendency and air release performance of domestic oil are worse than that of imported oil,this is due to the surface polymerization of PAO molecule of domestic oil and the formation of surface active adsorption layer under high temperature oxidation conditions,which increase the foaming tendency and prolong the air release time,resulting in the deterioration of antifoaming performance.