Abstract
The simulation of the lubrication of aluminum-silicon (Al-Si) alloy cylinder-bore conditions is an important goal in automotive tribology. This study describes the use of X-ray absorption near edge structure (XANES) to determine the macro-chemistry of zinc-dialkyl-dithiophosphates (ZDDPs) antiwear (AW) films formed on A383, an Al-Si alloy. The temperature dependence of the chemistry and mechanical properties were examined using X-ray photoelectron emission microscopy (X-PEEM), and imaging indentation techniques. Our findings suggest that ZDDPs break down to form polyphosphate glasses, which have different chemical natures and depend on the underlying substrate. Furthermore, the chemical nature of the films appears temperature dependent on both the macro- and micro-scale. Not only are the chemical species different, but the mechanical properties also differ, depending on the region upon which an AW pad is formed. Through the use of focused ion beam (FIB) milling, we can determine the film thickness, which was previously estimated from the P K-edge XANES areal density of samples with known thicknesses.
Original language | English |
---|---|
Pages (from-to) | 103-117 |
Number of pages | 15 |
Journal | Tribology Letters |
Volume | 26 |
Issue number | 2 |
DOIs | |
State | Published - May 2007 |
Bibliographical note
Funding Information:The authors would like to thank Mr. Ross Davidson and the rest of the staff at Surface Science Western (SSW) for assistance in acquiring the SEM/EDX data. We are also grateful to Dr. David Munoz-Paniagua for useful discussions regarding nanoindentation, and to Mr. Phil Shaw, Mr. Brian Dalrymple, Mr. Barakat Misk, and Dr. Leighton Coatsworth, all from The University of Western Ontario, and Dr. Todd Simpson from the Nanofabrication Laboratory, also from The University of Western Ontario. We are also obliged to Dr. Franziskus Heigl and Dr. Astrid Jürgensen, from the Canadian Synchrotron Radiation Facility (CSRF), University of Wisconsin, Madison, for their technical support; Imperial Oil of Canada (ESSO) for oil additives; and the National Science Foundation (NSF) for supporting the SRC under grant # DMR-0537588. This work was financially supported by General Motors of Canada Ltd., General Motors R&D center, the National Research Council of Canada (NRC), and the Natural Sciences and Engineering Research Council of Canada (NSERC).
Keywords
- FIB
- Mechanical properties
- Nanoindentation
- Polyphosphate
- SEM-EDX
- Tribofilm
- X-PEEM
- XANES
- ZDDP
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Surfaces and Interfaces
- Surfaces, Coatings and Films