ASTM D5483 Oxidation Induction Time of Lubricating Greases by Pressure Differential Scanning Calorimetry
Some greases or oils react with atmospheric oxygen to produce insoluble gums and sludges, which may decrease the performance of the lubricant. To lessen the rate of oxidation, antioxidants are added. This test may be used to compare antioxidants and may predict the relative life of a lubricant. It requires a small amount of sample and it gives results in hours rather than days, weeks or even months as required by other tests.
A small quantity of grease (ASTM D5483) or oil (ASTM D6186) is heated to a specified temperature and then pressurized with oxygen. The pressure and temperature are maintained until an exothermic reaction occurs, up to 120 minutes. If the reaction occurs in less than ten minutes, a lower temperature is tested as per the method (210ºC, 180ºC, 155ºC for grease and 210ºC, 180ºC, 155ºC, 130ºC for oil). The time from pressurization to exotherm is reported. Please let us know if you require a temperature other than those specified in the method.