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Local order in surface ZDDP reaction films generated on engine parts, using EXAFS and related techniques
Author(s) -
Belin M.,
Martin J. M.,
Tourillon G.,
Constans B.,
Bernasconi C.
Publication year - 1995
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010080102
Subject(s) - lubricant , extended x ray absorption fine structure , yield (engineering) , materials science , amorphous solid , absorption (acoustics) , base oil , chemical engineering , composite material , chemistry , scanning electron microscope , absorption spectroscopy , crystallography , optics , engineering , physics
The study of reaction films generated in a mild wear lubricated process remains a topic of interest. We present in this paper the latest results obtained by the structural analysis of reaction films directly on friction surfaces. An experimental engine setup is used, in which a cam and follower system is externally driven without combustion. The system is lubricated with a base oil containing ZDDP (zinc dialkyl‐dithiophosphate). After the wear test, the engine parts are analysed by the EXAFS technique (Extended X‐Ray Absorption Fine Structure) in the Total Electron Yield configuration. It is found that the build‐up of the film greatly depends on the formulation of the lubricant, and on the test conditions. In the film formed with ZDDP, the initial Zn‐S bonding changed to ZN‐O in a completely amorphous arrangement. The nature of the wear debris is found to be very similar to the surface of the reaction film. These results are discussed in terms of microscopic wear mechanisms.