Abstract
This study attempts to use ionic liquids (ILs) as oil additives to lubricate oxygen-diffusion (OD) case-hardened titanium for improved friction and wear behavior. Four oil-soluble ILs were used as additives in a base oil for boundary lubrication of an OD-treated Ti-6Al-4V surface sliding against a bearing steel ball. The ILs improved the friction behavior to various extents and the two phosphate ILs clearly outperformed the conventional ZDDP. Unlike ZDDP that adversely caused a higher material loss, ILs exhibited excellent wear protection suggesting good material-chemical compatibility. Particularly, the carboxylate IL protected the OD-Ti surface from any measurable wear. The morphology and chemical composition of the worn surfaces and tribofilms were examined to gain insights of the anti-wear mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 342-348 |
| Number of pages | 7 |
| Journal | Tribology International |
| Volume | 136 |
| DOIs | |
| State | Published - Aug 2019 |
Funding
This manuscript has been authored by UT-Battelle , LLC under Contract No. DEAC05-00OR22725 with the U.S. Department of Energy . The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research by the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). This manuscript has been authored by UT-Battelle, LLC under Contract No. DEAC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research by the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).The authors thank Dr. A.G. Bro and C. Dubin from ExxonMobil for providing the PAO base oil, E. Bardasz from Lubrizol for providing the ZDDP, Drs. J. Dyck and E. Conrad from Cytec Industries for providing phosphonium cation feedstocks, and D. Coffey from ORNL for preparing the STEM sample, respectively. Research was sponsored by the Vehicle Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE). Electron microscopy characterization was in part performed at ORNL's Center for Nanophase Materials Sciences, sponsored by the Scientific User Facilities Division, Office of DOE-BES. The support by the National Natural Science Foundation of China (No. 51575402) and Chinese Academy of Sciences (CAS) during the visits of H. Duan and W. Li to ORNL, respectively, are also appreciated.
| Funders | Funder number |
|---|---|
| Office of DOE-BES | |
| Scientific User Facilities Division | |
| U.S. Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| Vehicle Technologies Office | |
| National Natural Science Foundation of China | 51575402 |
| Chinese Academy of Sciences |
Keywords
- Ionic liquid
- Lubrication
- Oxygen diffusion
- Titanium