Dorgham, A, Neville, A, Ignatyev, K et al. (2 more authors) (2017) An in-situ synchrotron XAS methodology for surface analysis under high temperature, pressure and shear. Review of Scientific Instruments, 88 (1). 015101. ISSN 0034-6748
Abstract
The complex tribochemical nature of lubricated tribological contacts is inaccessible in real time without altering their initial state. To overcome this issue, a new design of a pin-on-disc tribological apparatus was developed and combined with synchrotron X-ray absorption spectroscopy (XAS). Using the designed apparatus, it is possible to study in situ the transient decomposition reactions of various oil additives on different surfaces under a wide range of realistic operating conditions of contact pressure (1.0–3.0 GPa), temperature (25–120 °C), and sliding speed (30–3000 rpm or 0.15–15 m/s). To test the apparatus, several tribological tests were performed at different shearing times ranging from 2.5 to 60 min. These tests were carried out under helium atmosphere at a temperature of 80 °C, contact pressure of 2.2 GPa, and sliding speed of 50 rpm. The XAS experiments indicate that the zinc dialkyldithiophosphate antiwear additive decomposes in the oil to form a tribofilm on the iron surface at different reaction kinetics from the ones of the thermal film. The tribofilm composition evolves much faster than the one of the thermal film, which confirms that the formation of the tribofilm is a thermally activated process similar to the one of the thermal film but accelerated by shear. Furthermore, the results indicate that the sulfur of the formed film, whether a tribofilm or a thermal film, appears initially in the form of sulfate, with some sulfide, which under heat or shear is reduced into mainly sulfide.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Published by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in "Dorgham, A, Neville, A, Ignatyev, K et al (2017) An in-situ synchrotron XAS methodology for surface analysis under high temperature, pressure and shear. Review of Scientific Instruments, 88 (1). 015101," and may be found at [https://doi.org/10.1063/1.4973354]. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Functional Surfaces (Leeds) |
Funding Information: | Funder Grant number EU - European Union 317334 |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Dec 2016 11:06 |
Last Modified: | 16 Apr 2020 14:28 |
Published Version: | https://doi.org/10.1063/1.4973354 |
Status: | Published |
Publisher: | AIP Publishing |
Identification Number: | 10.1063/1.4973354 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:109559 |