Abstract:An oil-soluble rare earth compound,samarium isooctoxyborate,was synthesized and used as an antiwear and extreme pressure additive for lubricatingoils.Its tribological performances were evaluated with a four-ball machine and a ring-on-block rig.In addition,surface analyses with Auger electron spectroscopy and Xray photoelectron spectroscopy were also conducted to study the surface film formed by the additive under boundary lubrication conditions.The test results s how that the additive exhibits good friction-reducing ability,good antiwear property and excellent extreme pressure performance.Surface analyses further disc lose the coexistence of organic film,oxidation film and permeating film on the rubbing surface,which contributed to improve the tribological properties of the base oil.

Key words: tribology;samarium isooctoxyborate;antiwear;friction-reducing;extreme pressure