Volume 4, Issue 7 (July 2007)

    Study of the ZDDP Antiwear Tribofilm Formed on the DLC Coating Using AFM and XPS Techniques

    (Received 4 December 2006; accepted 9 July 2007)

    Published Online: 2007

    CODEN: JAIOAD

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    Abstract

    To meet the challenge of the increasing demand of fuel economy, in recent years low friction nonferrous coatings such as diamond-like carbon (DLC) coatings have become very popular for automotive tribo-components. The interaction of lubricant additives, which are designed for ferrous surfaces, with nonferrous coatings is an important issue for the automotive and lubricant industries. The aim of this paper is to establish a link between the evolution of antiwear zinc dialkyl dithiophosphate (ZDDP) tribofilm and the tribological performance of a DLC coating under boundary lubrication conditions. Experiments were performed in a pin-on-plate reciprocating tribotester to produce the tribofilm. Atomic force microscopy (AFM) was used to record high resolution topographical images of the ZDDP films while chemical analysis of the ZDDP tribofilms was performed using X-ray photoelectron spectroscopy (XPS). Results in this study show that the ZDDP tribofilm consists of short chain zinc pyrophosphate (Zn2P2O7) and zinc metaphosphate (ZnOP2O5), and it is formed along the raised portion of the initial marks of the DLC surface.


    Author Information:

    Haque, T.
    Institute of Engineering Thermofluids, Surfaces and Interfaces (iETSI), School of Mechanical Engineering, University of Leeds, Leeds,

    Morina, A.
    Institute of Engineering Thermofluids, Surfaces and Interfaces (iETSI), School of Mechanical Engineering, University of Leeds, Leeds,

    Neville, A.
    Institute of Engineering Thermofluids, Surfaces and Interfaces (iETSI), School of Mechanical Engineering, University of Leeds, Leeds,

    Kapadia, R.
    Infineum UK Limited, Oxfordshire,

    Arrowsmith, S.
    Infineum UK Limited, Oxfordshire,


    Stock #: JAI100937

    ISSN: 1546-962X

    DOI: 10.1520/JAI100937

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    Author
    Title Study of the ZDDP Antiwear Tribofilm Formed on the DLC Coating Using AFM and XPS Techniques
    Symposium Automotive Lubricant Testing and Additive Development, 2006-12-05
    Committee D02