2134/36042
Jamal Umer
Jamal
Umer
Nick Morris
Nick
Morris
Michael Leighton
Michael
Leighton
Ramin Rahmani
Ramin
Rahmani
Sashi Balakrishnan
Sashi
Balakrishnan
Homer Rahnejat
Homer
Rahnejat
Nano and microscale contact characteristics of tribofilms derived from fully formulated engine oil
Loughborough University
2018
AFM in lateral force mode (LFM)
Tribo-film
ZDDP
Friction
Mechanical Engineering not elsewhere classified
Mechanical Engineering
2018-11-16 14:47:02
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Nano_and_microscale_contact_characteristics_of_tribofilms_derived_from_fully_formulated_engine_oil/9547418
A systematic approach is required in order to determine the frictional characteristics of a contacting pair in the presence of a tribofilm. Despite the clear benefits in functionality and in reducing wear, the generation of ZDDP-based tribofilms often lead to increased frictional losses. Such an increase is also observed in the tribometric tests reported here, as well as in open literature. This paper investigates the underlying mechanics for the rise in friction using an integrated methodology, based upon Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). The use of an analytical contact mechanics model demonstrates that the pressure coefficient of boundary shear strength, measured using lateral force microscopy, provides an explanation for the observed increase in measured friction at micro-scale.