Synthesis and tribological properties of ferrous octoxyborate as antiwear and friction-reducing additive of lubricating oil

An oil-soluble compound containing ferrous iron and boron-ferrous octoxybor ate was synthesized. The antiwear and friction-reducing properties of the c ompound as a lubricating oil additive were evaluated using a four-ball and a block-on-ring tribotester. Results indicated that both the wear resistanc e and the load-carrying capacity of a 500 SN base oil were improved and its friction coefficient was decreased by the additive. The wear scar, after b eing cleaned using an ultrasonic bath in ligroin and in distilled water, wa s characterized with SEM and XPS. Diboron trioxide, FeB and Fe2B were all f ound to have been deposited on the wear-scar surface. It was this depositio n that provided the oil with excellent antiwear and friction-reducing prope rties.