Title: Tribological performance of DLC/DLC and steel/DLC contacts in the presence of additivated oil

Authors: Abdul Mannan; M.F.M. Sabri; Md. Abul Kalam; Masjuki H. Hassan

Addresses: Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia ' Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia ' Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia ' Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia

Abstract: In this study, the tribological properties of ta-C DLC were largely influenced by the counter surfaces and additives. The DLC/DLC contact showed approximately 60% lower wear when tested with additivated oil compared to that of base oil and this result was 66% in steel/DLC contact. Friction coefficient in DLC/DLC contact was lower than in steel/DLC contact under both oils. But however, both contacts showed slightly higher friction coefficient under additivated oil compared to that of base oil. In steel/DLC, the thermo-chemical reaction between carbon and iron and/or the fusion of the transferred particles were prevented by additives which were present under base oil. The fracture found on DLC surface in steel/DLC contact under additivated oil indicates that the tribolayer formed on the steel surface would be of brittle nature. The passivation of surfaces in DLC/DLC contact by additives prevented the damage which was observed under base oil.

Keywords: DLC films; vegetable oil; four ball tribo-testing; anti-wear additive; friction and wear.

DOI: 10.1504/IJSURFSE.2018.090055

International Journal of Surface Science and Engineering, 2018 Vol.12 No.1, pp.60 - 75

Received: 21 Feb 2017
Accepted: 23 Sep 2017
Published online: 27 Feb 2018 *

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