Abstract: Ionic liquid of alkylimidazolium tetrafluoroborate was prepared and evaluated as a kind of promising versatile lubricant for the contact of steel/steel, steel/aluminum, steel/copper, steel/SiO 2, Si 3N 4/SiO 2, steel/Si(100), steel/sialon ceramic, and Si 3N 4/sialon ceramic. As the results, the synthetic ionic liquid shows excellent tribological behavior and is superior to phosphorzene and perfluoropolyether in terms of friction reduction ability and load carrying capacity.