| AVS 54th International Symposium | |
| Tribology | Friday Sessions |
| Session TR4+SE-FrM |
| Session: | Friction and Wear of Engineered Surfaces Macro- to Nanoscale Approaches |
| Presenter: | Y.-R. Li, University of Western Ontario, Canada |
| Authors: | P.R. Norton, University of Western Ontario, Canada G. Pereira, University of Western Ontario, Canada Y.-R. Li, University of Western Ontario, Canada A. Lachenwitzer, Cameco Corporation A. Alpas, University of Windsor, Canada W. Capehart, General Motors |
| Correspondent: | Click to Email |
Much effort has been spent on the chemical and mechanical characterization of antiwear films formed from ZDDP additives in automobile engines and on the mechanisms of their formation. By contrast, much less effort has been devoted to evaluating the wear itself. This is largely because the wear rates required in the engine are of order nm/hr, and accelerated testing under high loads is unacceptable because of the ubiquity of wear-rate transitions which make extrapolation to low loads difficult or impossible. The absence of relevant low-load (ultra-mild) wear data means that it is currently not generally possible to correlate the film characterization and wear rate studies, creating a huge gap in our understanding of wear. We are addressing this unsatisfactory situation by developing new techniques for directly measuring wear rates down to nm/hr in tests lasting a few hours. These techniques must be capable of measuring both the initial and long-term wear rates, be valid in the presence of surface films and take account of retention of material during wear. The strategy involves the implantation of Au atoms into the near-surface 100 nm region of a material (currently 52100 steel or an Al-Si alloy), and the determination of the loss of gold from the samples by means of Rutherford Backscattering (RBS) and Heavy Ion Backscattering (HIBS), and the accumulation of gold in the lubricant by Neutron Activation Analysis (NAA). The initial profiles can be either uni-modal or multi-modal with depth, to provide sensitivity to short and long-term behaviour. The analysis of both sample and lubricant/debris quantitatively accounts for all implanted gold, and the depth resolution of HIBS permits determination of the location of the residual gold in the samples.