New strategy for reducing the EHL friction in steel contacts using additive-formed oleophobic boundary films

Kalin, Mitjan (author), Kus, Maja (author)

In this study we present a mechanism for the elastohydrodynamic (EHD) friction reduction in steel/steel contacts, which occurs due to the formation of oleophobic surface boundary layers from common boundary-lubrication additives. Several simple organic additives (amine, alcohol, amide, and fatty acid) with different molecular structures were employed as the model additives. It was found that the stronger chemisorption at 100 °C, rather than the physisorption at 25 °C, is more effective in friction reduction, which reaches 22%. What is more, EHD friction reduction was obtained in steel/steel contacts without use of the diamond-like carbon (DLC) coatings with their wetting or thermal effect, which was previously suggested as possible EHD friction reduction mechanism; yet about the same friction reduction of about 20% was obtained here-but with much simpler and less expensive technology, namely with the adsorbed oleophobic surface layers. A small variation in the additive's molecular structure results in significant changes to the friction, indicating good potential in future EHD lubrication technology, where these additives could be designed and well optimised for notable reduction of the friction losses in the EHD regime.

• Language: English
• Keywords: elastohydrodynamic lubrication, friction, additives, oleophobic layer, boundary slip
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Publication date: 15.05.2020
• Year: 2021
• Number of pages: Str. 1346-1360
• Numbering: Vol. 9, iss. 6
• PID: 20.500.12556/RUL-139398
• UDC: 539.92
• ISSN on article: 2223-7690
• DOI: 10.1007/s40544-020-0403-2
• COBISS.SI-ID: 30376451
• Publication date in RUL: 02.09.2022

Record is a part of a journal

• Title: Friction
• Shortened title: Frict.
• Publisher: Tsinghua University Press
• ISSN: 2223-7690
• COBISS.SI-ID: 525351449

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 15.05.2020

Secondary language

• Language: Slovenian
• Keywords: elastohidrodinamično mazanje, trenje, aditivi, oleofobna plast, mejni zdrs

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0231
• Name: Tribologija