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Tribologically activated surface layers in lubricated DLC contacts
Author(s) -
Podgornik B.,
Vižintin J.
Publication year - 2008
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2741
Subject(s) - lubricant , reciprocating motion , materials science , lubrication , boundary lubrication , tribology , ball (mathematics) , composite material , metallurgy , bearing (navigation) , computer science , mathematical analysis , mathematics , artificial intelligence
In the past, adequate functionality of high‐performance components would have been impossible without advanced lubricant additive chemistry and proper lubricant formulation. Especially anti‐wear (AW) and extreme‐pressure (EP) additives are crucial in minimising friction and wear and protecting contact surfaces under severe contact conditions. Introduction of diamond‐like carbon (DLC) coatings, on the other hand, opens further possibilities in improving performance of highly loaded components, which can no longer be achieved only by lubricant design. The aim of the present research was to determine the mechanism responsible for the low‐friction behaviour of boundary lubricated DLC coatings when lubricated with lubricants containing EP or AW additives and to investigate the influence of contact conditions. Tests were performed under reciprocating sliding motion using ball on flat test configuration, with ball‐bearing steel ball being loaded against undoped and W‐doped DLC‐coated discs, respectively. Results of the investigation clearly show that in the case of W‐doped DLC coatings, low‐friction behaviour under boundary lubrication is governed by formation of WS 2 ‐containing tribolayers, which are contact conditions dependent and can reduce friction by more than 50%. Copyright © 2008 John Wiley & Sons, Ltd.