Influence of surface modification technologies on friction of conformal tribopair in boundary and full film lubrication regimes
2010 (English)In: 14th Nordic Symposium on Tribology: NORDTRIB 2010 : Storforsen, Sweden, June 8-11, 2010, Luleå: Luleå tekniska universitet, 2010Conference paper (Refereed)
Moving machine assemblies are generally designed to operate in full film lubrication regime to ensure high efficiency and durability of components. However, it is not always possible to ensure this owing to changes in operating conditions such as load, speed, temperature etc. The overall frictional losses in machines are thus dependent on the operating lubrication regimes (boundary, mixed or full-film). The present work is thus aimed at investigating the role of different surface modification technologies on friction of a conformal tribopair both in boundary and full film lubrication regimes. The conformal pair chosen is a hydrodynamic bearing with some hydrostatic lift.A special test rig comprising of two bearings was built for the experimental studies. Tribological tests were conducted in a wide speed range so as to enable studies in all lubrication regimes i.e., in boundary, mixed and full-film lubrication.The influence of application of different surface modification technologies on friction has been studied. In all, rollers with five coatings (four hard DLC coatings and one self-lubricating coating) and two rollers without coating having different surface finish. Friction measurements were made on the new as well as the previously run-in components. The different coatings exhibit different levels of boundary friction, with the self-lubricating coating having lowest boundary friction, closely followed by those with hard DLC coatings. The softer amongst the hard DLC coatings showed similar boundary friction compared to that with uncoated rollers. The lift-off speed, i.e., the transition between full-film to mixed and boundary lubrication mainly governed by the surface topography characteristics. A smooth surface finish can be achieved either by polishing before the test or by effective running in of the new surface. The effectiveness of running-in of surfaces was influenced by the surface roughness and hardness of the interacting surfaces.
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2010.
Research subject Machine Elements
IdentifiersURN: urn:nbn:se:ltu:diva-35198Local ID: 9a13f730-82b7-11df-ab16-000ea68e967bISBN: 978-91-7439-124-4 (PDF)OAI: oai:DiVA.org:ltu-35198DiVA: diva2:1008450
Nordic Symposium on Tribology : 08/06/2010 - 11/06/2010
Godkänd; 2010; Bibliografisk uppgift: CD-ROM; 20100628 (ysko)2016-09-302016-09-30Bibliographically approved