Dorgham, A, Azam, A orcid.org/0000-0002-3510-1333, Parsaeian, P et al. (3 more authors) (2021) Nanoscale viscosity of triboreactive interfaces. Nano Energy, 79. 105447. ISSN 2211-2855
Abstract
It has been long speculated that the good antiwear properties of the nano-thin triboreactive interfaces might have a rheological origin that can greatly influence their friction, lubrication and antiwear characteristics, which account for nearly one quarter of the worldwide total energy consumption. However, the measurement of the nanoscale viscosity of such tribological interfaces is still a challenging task. This is mainly due to their ultralow thickness, i.e. typically 150 nm, high viscosity and reactivity, which make the currently used bulk, interfacial or micro-gap rheological techniques inadequate. Here we demonstrate two methods, i.e. creep and squeeze flow, that can be used to quantify the viscosity of triboreactive films in-situ as they form and ex-situ after formation. Films generated from the zinc and ashless dialkyldithiophosphate (ZDDP and DDP) antiwear additives were analysed as model systems because of their industrial and academic importance. The results confirm that the formed tribofilms behave as molten glass with an average viscosity ranging from to Pa s. During its formation, the molten glass showed rich intrinsic rheological properties that allowed them to maintain local order on the nanoscale through the motion and reconfiguration of single and multiple patches within the formed film, which can significantly predetermine its superior antiwear properties. The findings of this study open future opportunities for optimizing the nano-flowable glass to efficiently control the lubrication of tomorrow’s engines without the need of any environmentally harmful oil additives.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 Elsevier Ltd. All rights reserved. This is an author produced version of an article published in Nano Energy. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Nanoscale viscosity; Rheology; Creep; Squeeze flow; Tribology; ZDDP tribofilm |
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: | 07 Dec 2020 13:13 |
Last Modified: | 01 Oct 2021 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.nanoen.2020.105447 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:168709 |