Abstract
The nanomechanical properties of antiwear films formed from zinc dialkyl-dithiophosphates (ZDDPs) on steel have been studied by nanoindentation techniques as a function of temperature. X-ray absorption P K- and L- near edge structure (XANES) spectroscopy has shown that films prepared from oils containing ZDDPs on 52100 steel (pin on flat coupons) consist primarily of medium chain polyphosphates with sulphur (S K-edge) predominantly present as sulphide. Using various scanning probe techniques, high-resolution topographic images and mechanical properties can be extracted at the same length scale. Using focused ion beam (FIB) milling we have compared real cross-sectional film thickness with a value estimated from the P K-edge XANES. We report the first measurements of the elastic modulus of the antiwear films at elevated temperatures relevant to the automobile operating conditions (T ≤ 200 °C). The antiwear films demonstrated a relatively constant indentation modulus over a wide range of temperatures consistent with their efficacy in reducing wear by preventing asperity contact.
Original language | English |
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Pages (from-to) | 461-470 |
Number of pages | 10 |
Journal | Wear |
Volume | 262 |
Issue number | 3-4 |
DOIs | |
State | Published - Feb 4 2007 |
Bibliographical note
Funding Information:The authors would like to thank Mr. Phil Shaw and Mr. Brian Dalrymple of the Physics Machine Shop, Mr. Gord Wood of the Earth Sciences Department and Dr. Leighton Coatsworth (all from The University of Western Ontario) for useful discussions and technical support, and to Dr. Todd Simpson from the Nanofabrication Laboratory, also from The University of Western Ontario for assistance in acquiring FIB/SEM data. We are also grateful to Dr. Astrid Jürgensen and Dr. Franziskus Heigl from the Canadian Synchrotron Radiation Facility (CSRF), University of Wisconsin, Madison, for their technical support, and the National Science Foundation (NSF) for supporting the SRC under grant # DMR-0084402. This work was financially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), General Motors of Canada Ltd., and by the National Research Council of Canada (NRC) which supports the Canadian Synchrotron Radiation Facility at the Aladdin ring in Stoughton, Wisconsin. Finally we would like to thank Hysitron Inc. for technical advice on the operation of the Triboindenter ® .
Keywords
- Antiwear films
- Elastic modulus
- Variable temperature
- XANES
- ZDDPs
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry