Ionic Liquids Based on Phosphonium Cations As Neat Lubricants or Lubricant Additives for a Steel/Steel Contact

摘要

After doing several miscibility essays with eight ionic liquids (ILs) and four base oils, the ILs tri(butyl)-ethylphosphonium diethylphosphate [P_(4,4,4,2)] [C2C2PO4] and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)-trifluorophosphate [P_(6,6,6,14))] [(CsF5)3PF3] were selected to be studied as lubricant additives. The neat IL [P_(4,4,4,2)] [C2C2PO4], the base oils, and several blends were characterized in terms of density, viscosity, and thermal stability. The tribological performance of the miscible base oil/IL blends (1 wt %) and the neat [P_(4,4,4,2)] [C2C2PO4] were evaluated for the lubrication of an AISI 420 steel-100Cr6 steel contact pair. The friction coefficients and wear volumes obtained are also compared with those corresponding to the pure base oils and their mixtures with conventional additive zinc dialkyldithiophosphate (ZDDP).