Abstract
Over the years many analytical tools have been developed to measure zinc dithiophosphate depletion in engine oil formulations. Many of these tools are obvious ones, such as infrared spectroscopy and thin layer chromatography; however, in this paper we report on our study using X-Ray Absorption Near-Edge Structure (XANES) Spectroscopy for examining zinc dithiophosphate depletion in oils. Thus, XANES joins the constellation of techniques available to the additive chemist for study of the status of the zinc dithiophosphates in used oils. Comparison of this XANES technique with a more traditional technique, 31P nuclear magnetic resonance (NMR) spectroscopy, showed that XANES spectroscopy gave data consistent with NMR. Since these were diesel engine oils, the authors were also able to examine, by solid-state NMR, the soot from two fully formulated engine oils, one a high wear and one a low wear oil. By this study the authors were able to show that the Rounds' hypothesis for zinc dithiophosphate depletion and wear appears not to be valid.
Presented as a Society of Tribologists and Lubrication Engineers Paper at the ASME/STLE Tribology Conference in Cancun, Mexico October 27–30, 2002
KEY WORDS:
Notes
Presented as a Society of Tribologists and Lubrication Engineers Paper at the ASME/STLE Tribology Conference in Cancun, Mexico October 27–30, 2002