4 Conclusions
According to the color investigation of the oxidized lubrication oil
samples, we found that the color of the oxidized oil samples is mainly
determined by the amount and species of antioxidants and oxidation
conditions (including catalysts, temperature, time). Based on the
incipient oxidation temperature, total acid number and tribological
performances tests, the overall performances of the fully formulated
aviation lubrication oil (T501 and Tz516 are used as antioxidants) would
be remarkably reduced when the color number exceeds 23 at
250 oC oxidized for 2 hours. In the same case of fully
formulated aviation lubrication oil with T531 used as antioxidants, the
performances would decrease significantly when the color number exceeds
21 under same reaction conditions. The color number is proved that have
potential practical applications in the field of fast determination of
the quality and residual lifetime of the in-service aviation lubrication
oil.