Corrosion activity and solubility in polar oils of three bis(trifluoromethylsulfonyl) imide/bis(trifluoromethylsulfonyl) amide ([NTF2]) anion-based ionic liquids.

The corrosion behaviour and solubility of three bis(trifluoromethylsulfonyl)amide1 ([NTf2]) anion-based ionic liquids: 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C12MIM][NTf2]), tributylmethylammonium bis(trifluoromethylsulfonyl)amide ([N4441][NTf2]), and methyltrioctylammonium bis(trifluoromethylsulfonyl)amide ([N1888][NTf2]), as a component in a mixture with different base oils were analysed. Six polar oils suitable for use in lubrication were utilized as base oil. Solubility tests were performed by using turbidimetry, and corrosion was checked at 4 v/v% by examining the roughness and chemical composition of the surface after 21 days. The results showed that long carbon chains in the cation improve the solubility greatly in diesters and slightly in polyolesters. Corrosion was not detected at this concentration

Lubrication performance of an ammonium cation-based ionic liquid used as an additive in a polar oil.

This paper studies the tribological behavior of the ionic liquid methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N 1888 ][NTf 2 ]) as additive at different concentrations (1.25, 2.50, 3.75 and 5.00 wt%) in a polar base oil (diester). A tribometer using a ball-on-disk reciprocating configuration under fully flooded lubrication was used at a frequency of 15 Hz, at three different loads (40, 80 and 120 N), stroke length of 4 mm, and duration of 45 min. Worn surface on the disk was studied by confocal microscopy, SEM and XPS. Main results showed similar coefficient of friction for all lubricant samples; but different wear results were found at different loads, probably related with the chemical states found for fluorine on the worn surface and the temperature-dependent adsorption-desorption processes

Wettability and corrosion of [NTf2] anion-based ionic liquids on steel and PVD (TiN, CrN, ZrN) coatings

Thewetting and corrosion behavior of three bis(trifluoromethylsulfonyl)imide-based ionic liquids: 1-Dodecyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide [C12MIM][NTf2], tributylmethylammonium bis(trifluoromethylsulfonyl)imide [N4441][NTf2] and methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888][NTf2] are tested in this research. The surface tension was measured for temperatures of 293–353 K resulting in the expected linearly decreasing behavior with temperature increase. In addition, contact angle measurements were made on AISI 52100 steel and three coatings (TiN, CrN and ZrN) obtained by PVD technique, finding the regular behavior in hydrophobic (non-polar) systems: high contact angles led to high surface tensions. Complementary parameters like spreading parameter and polarity fraction were calculated to enhance the wetting evaluation of these ionic liquids. [N1888][NTf2]/TiN resulted as the best IL-surface combination for a good wettability, due to the higher dispersion of the charge on the large size cation in this IL and the higher values of total and polar component of the surface free energy for this coating. Finally, SEM-EDS analysis determined that [N1888][NTf2]/ZrN was the best option in order to avoid corrosion problems. The evaporation of water, present as impurity in the ionic liquids, was found the main reason because of corrosion did not occur in the tests carried out at 100 °C

Friction, wear and tribofilm formation with a [NTf2] anion-based ionic liquid as neat lubricant.

This paper presents the tribological behavior of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888][NTf2] ionic liquid as neat lubricant in a steel-steel contact. A ball-on-disk reciprocating rig was used: firstly, at constant frequency (15 Hz) under both variable loads (40 to 120 N) and sliding distances (216, 324 and 432 m); and secondly, at different frequencies (10 to 30 Hz) and constant both load (80 N) and sliding distance (432 m). Slight friction variations and increasing wear with rising loads was found at constant frequency. Different behavior was found at constant load. The tribofilm thickness formed on the worn surface was closely related to testing conditions and controlled tribological behavior