Influence of electric potentials on surface damage in rolling–sliding contacts under mixed lubrication
File(s)
Published version
OA Location
Author(s)
Yousuf, Ammad
Spikes, Hugh
Guo, Liang
Kadiric, Amir
Type
Journal Article
Abstract
Shaft voltages in electric vehicle drivetrains are believed to be capable of causing significant damage to rolling bearing surfaces. While surface damage due to high current discharge in full-film lubrication is relatively well understood, the effects of electric potentials on surface damage and tribofilm formation in thin-film, mixed lubrication are rarely studied and remain poorly understood. This paper investigates the influence of relatively low DC potentials (1 V, 5 V) and currents (<10 mA) on wear and tribofilm growth in rolling–sliding contacts in operating mixed lubrication. A suitably modified ball-on-disc MTM-SLIM rig is used to apply an electric potential across a lubricated ball-on-disc contact. Tests were conducted with bearing steel specimens and three oils: PAO base oil, PAO with antiwear additive ZDDP, and a commercial automatic transmission fluid (ATF). The effect of electric polarity was an integral part of the study. The results reveal that even small electric potentials and currents significantly affect wear. For the oil containing ZDDP, electric potential both suppressed the formation of tribofilm and significantly increased the wear on the anodic surface, be it the ball or the disc. The wear was localised in discrete bands within the rubbing track. ZDDP film was shown to be electrically resistive and it is postulated that the non-uniform nature of the ZDDP film leads to the concentration of current within the thin-film regions and this high current density causes wear in these local areas (wear bands) via electric discharge. In contrast, with the ATF, electric potential promoted tribofilm on the anode but resulted in higher wear on the cathode disc. The study highlights a complex interplay between the electric potential, tribofilm formation, the consequent distribution of electrical resistance within the contact, and the resulting wear evolution.
Date Issued
2025-06-01
Date Acceptance
2025-02-25
Citation
Tribology Letters, 2025, 73 (2)
ISSN
1023-8883
Publisher
Springer
Journal / Book Title
Tribology Letters
Volume
73
Issue
2
Copyright Statement
© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
10.1007/s11249-025-01977-2
Subjects
BEARING CURRENTS
Electric vehicles
Electrified contacts
Engineering
Engineering, Chemical
Engineering, Mechanical
FRICTION
Mixed lubrication
Science & Technology
SHAFT VOLTAGES
Technology
Wear
WEAR
Publication Status
Published
Article Number
45
Date Publish Online
2025-03-14