ABSTRACT
Abstract .................................................................................................................. 217 9.1 Introduction .................................................................................................. 218 9.2 Experimental ................................................................................................ 219
9.2.1 Ionic Liquids ..................................................................................... 219 9.2.2 Friction and Wear Test ......................................................................220 9.2.3 Surface Analysis ............................................................................... 221
9.3 Results of Friction and Wear Test ................................................................. 221 9.3.1 Viscosity ........................................................................................... 221 9.3.2 Lubricity of [BMIM][PF6] ............................................................... 222 9.3.3 Lubricity of [BMIM][TFSI] .............................................................223 9.3.4 Behavior of [BMIM][PF6] and [BMIM][TFSI] upon
Temperature Variation ...................................................................... 223 9.3.5 Effect of Mixing of [BMIM][PF6] and [BMIM][TFSI] at 50°C ....... 224 9.3.6 Effect of Mixing [PF6] and [TFSI] at 100°C ................................... 227
9.4 Results of XPS Analysis ...............................................................................228 9.4.1 XPS Analysis for Each Blend at 50°C ..............................................230 9.4.2 XPS Analysis for Each Blend at 100°C ............................................ 233
9.5 Discussions ................................................................................................... 235 9.6 Conclusion .................................................................................................... 236 References .............................................................................................................. 236
reactive lm on a friction surface. However, it has also been reported to lead to increased wear because of the corrosion on the sliding surface due to the decomposition of the ionic liquid during the friction process. This corrosion was found to be caused by the generation of anion-derived uoride, and it can be prevented by anion-derived phosphorus. However, because these studies used a single ionic liquid, the effectiveness and mechanism when using multiple ionic liquids in combination is unknown. Therefore, with a focus on reactive products generated on the sliding surface, the effect when using a combination of two different ionic liquids has been studied under steel-onsteel sliding contacts using a Schwingung-Reibung-Verschleiss (SRV) oscillating sliding tester at 50°C and 100°C. A surface analysis was conducted after the sliding test by using x-ray photoelectron spectroscopy (XPS). The results of the wear at 50°C revealed that the wear resistance increased by mixing a small amount of [BMIM][PF6] in [BMIM][TFSI]. The XPS analysis results showed that this antiwear effect was due to the generation of iron phosphate and FeF2. However, the antiwear effect was not observed at 100°C, and corrosion wear was observed despite the generation of iron phosphate and FeF2. This corrosion wear is postulated to be due to the generation of acid, derived from the [TFSI] anion, which affects the protective lm formed on the surface, leading to a functional degradation of the protective lm.
