Khaemba, DN orcid.org/0000-0001-7709-4736, Jarnias, F, Thiebaut, B et al. (2 more authors) (2017) The role of surface roughness and slide-roll ratio in the decomposition of MoDTC in tribological contacts. Journal of Physics D: Applied Physics, 50 (8). 085302. ISSN 0022-3727
Abstract
In this study, the role of surface roughness and slide-roll ratio in the decomposition and friction performance of molybdenum dialkyldithiocarbamate (MoDTC) has been investigated. Tribotests were carried out in a MiniTraction Machine (MTM) using steel discs of varying roughness rubbing against smooth steel balls in a sliding/rolling contact. Tests were conducted at slide-roll ratio (SRR) values of SRR=100% and 200%. Raman spectroscopy was used to perform chemical characterisation on the resulting wear scars. The friction performance of rough discs was not affected by the slide-roll ratio. On the other hand, increasing the slide-roll ratio from 100% to 200% in tests with smooth discs resulted in higher friction with large instabilities. Raman analysis showed significant differences in chemical composition of the wear scars generated after tests with smooth and rough discs. Wear scars generated using rough discs were mainly composed of MoS2 indicating complete MoDTC decomposition while those generated using smooth discs were composed of a mixture of MoS2, MoSx (x>2) and FeMoO4 indicating partial MoDTC decomposition. Numerical simulation of the contact revealed that under similar loading conditions rough surfaces have higher local pressures than smoother surfaces. It is proposed that higher local pressures in rough surfaces promoted complete MoDTC decomposition. The novel finding from results presented in this study is that at similar temperature and MoDTC concentration, the degradation of MoDTC within tribocontacts is highly dependent on the roughness of the tribopair. This is because surface roughness determines the local pressure at the asperity asperity contact.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 IOP Publishing Ltd. This is an author produced version of a paper published in Journal of Physics D: Applied Physics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Surface roughness; slide-roll ratio; MoDTC; MoS2; MoSx; FeMoO4; Raman spectroscopy |
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) |
Depositing User: | Symplectic Publications |
Date Deposited: | 05 Jan 2017 12:16 |
Last Modified: | 01 Feb 2018 01:38 |
Published Version: | https://doi.org/10.1088/1361-6463/aa5905 |
Status: | Published |
Publisher: | IOP Publishing |
Identification Number: | 10.1088/1361-6463/aa5905 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:110087 |