Evaluating the oxidation properties of lubricants via non-isothermal thermogravimetric analysis: Estimating induction times and oxidation stability
Leon A. Smook, Sathwik Chatra K R, Piet M. Lugt
Abstract
Applications operating at high temperatures may suffer from oxidative lubricant degradation. The current test methods to evaluate thermoxidative stability and performance are resource intensive and they often provide results that are difficult to extrapolate to application conditions where the temperatures are lower than the test temperature. In this paper, we present a method to evaluate the thermoxidative performance of lubricants via non-isothermal thermogravimetric experiments under conditions closer to application conditions. We can provide effective kinetic parameters for the oxidation process. Based on these parameters, we can simulate mass-loss in experiments at a constant temperature, and estimates of induction times of oils with different antioxidant concentrations agree well with experimental values. Additionally, the kinetic parameters may be used in grease life models.