Combined Nano- and Macrotribology Studies of Titania Lubrication Using the Oil-Ionic Liquid Mixtures

Abstract

The lubrication of titania surfaces using a series of ionic liquid (IL)–hexadecane mixtures has been probed using nanoscale atomic force microscopy (AFM) and macroscale ball-on-disk tribometer measurements. The IL investigated is trihexyl­(tetradecyl)­phosphonium bis­(2,4,4-trimethyl­pentyl)­phosphinate, which is miscible with hexadecane in all proportions. At both length scales, the pure IL is a much more effective lubricant than pure hexadecane. At low loads, which are comparable to common industrial applications, the pure IL reduces the friction by 80% compared to pure hexadecane; while the IL–hexadecane mixtures lubricate the titania surface as effectively as the pure IL and wear decreases with increasing IL concentration. At high test loads the adsorbed ion boundary layer is displaced leading to surface contact and high friction, and wear is pronounced for all IL concentrations. Nonetheless, the IL performs better than a traditional zinc–dialkyl–dithophosphate (ZDDP) antiwear additive at the same concentration.

Electroresponsive structuring and friction of a non-halogenated ionic liquid in a polar solvent: effect of concentration

“…In particular, ILs containing phosphorus-and boron-based ions have been identified as promising candidates for lubricant additives and have been shown to exhibit excellent electroresponsive and lubrication properties, both as neat lubricants and when dispersed at low concentrations in a base oil or greases. [11][12][13][14][15][16][17][18] Yet, a mechanistic understanding of how the interfacial structures and composition of IL boundary layers in a base fluid can be modified and controlled by an electric field (i.e., realising tribotronics), and importantly, how such behaviours may be affected by the bulk IL concentration, is still lacking.…”

Reactivity of oil‐soluble IL with silicon surface at elevated temperature

“…Therefore, ashless additives are proposed as anti‐wear additives instead of ZDDP . Soluble ILs are also suggested to be an effective alternative to ZDDP, especially when lubricating light alloys …”

Friction Determination by Atomic Force Microscopy in Field of Biochemical Science

“…Figure 6 b was adapted from a study on the strength of biological surfaces through simultaneously monitoring of topography and friction between probe and protein samples. Stores and co-workers [ 74 ] implemented friction force microscopy as a tool to measure the dynamic friction characteristics. A commercial AFM equipped with a liquid cell was employed (Multimode SPM with a Nanoscope IV control unit, Veeco Instruments, Santa Barbara, CA, USA).…”

“…( b ) Simultaneous determination of topography and friction force (right) or roughness (left) and versus load force of the scanning process. Adapted with permission from [ 74 ].…”