Evaluation of the Oxidative Stabilities of a Deuterated and Nondeuterated Neopentyl Polyol Ester for Bearing Tests

摘要

Several deuterated and nondeuterated neopentyl polyol ester basestocks have been evaluated for oxidative stability at 220 C using systematic screening and characterization tests. Also, experimental lubricating greases have been prepared from selected basestocks for motor bearing life tests. Assuming bearing life to be solely dependent on lubricant oxidative stability, the deuterated grease prepared from a pentaerythritol perdeutero tetrahexanoate (98.6 atom %) ester with low alkali metal content, is expected to exhibit a fivefold longer life than its nondeuterated analog, also with low alkali metal content. Nondeuterated lithium stearate was used as the grease thickener. A significant enhancement in oxidative stability occurs on combination of the dual effects of deuteration and alkali metal concentration in the presence of an amine-type antioxidant. The test data indicate the lubricants formulated in this manner have potential operating temperatures as high as 280 C.