Investigation of subsequent deposit growth on pre‐existing lubricant deposits: a substitutional growth model. (11th March 2016)

• Record Type: Journal Article
• Authors: Kouame, Sylvain‐Didier B.; Vander Wal, Randy L.; Perez, Joseph
• Is Part Of: Lubrication science. Volume 28:Number 5(2016)
• Page Start: 267
• Page End: 280
• Publication Date: 2016-03-11
• Subjects: carbonaceous deposit -- substitution -- oxidation -- lubricant -- pre‐deposit -- polymeric deposit -- substitution -- uniform layer; Tribology -- Periodicals; Lubrication systems -- Research -- Periodicals; Surfaces (Technology) -- Research -- Periodicals; 621.89
• DOI: 10.1002/ls.1330
• Languages: English
• ISSNs: 0954-0075

Abstract

Abstract: The Penn State Micro‐Oxidation (PSMO) test was used in an inverse manner to pre‐cover metallic pan surfaces with polymeric, transitioning and carbonaceous films. These pre‐coated pans were then used as the initial test specimen/surface upon which fresh lubricant samples were aged. The effects of pre‐deposits of varied ages were gauged against the baseline of a virgin metallic surface to decouple the lubricant‐deposit system towards resolving their effect upon further deposit growth. From such data, a uniform deposition model describing deposit formation and aging was developed. Chemical characterisation of PSMO deposits by Fourier transform infrared‐attenuated total reflectance and energy‐dispersive X‐ray spectroscope analyses provide additional supporting evidence of changes in chemical bonding (alkyl C–H and carbonyl C=O bond stretching vibrations) and composition (C‐ and O‐atom content) as the deposits undergo deoxygenation and dehydrogenation reactions. Across different aged oils and films, the substitution tests show a declining activity towards mass deposition with film age, interpreted as decline in reactivity. Copyright © 2016 John Wiley & Sons, Ltd.