Study on the synergistic lubrication mechanism between sulfur- phosphorus-free ionic liquid-type organic molybdenum and ZDDP

The designed synthesis of ionic liquid-type organic molybdenum (IOMo) compounds was investigated for their tribological performance as additives in alkylated naphthalene base oil, and their performance was compared with commercial additives. When IOMo is combined with ZDDP as additive, they synergistically enhance its anti-friction properties and further improve its anti-wear performance effectively. By analyzing worn surface, coupled with the adsorption performance of the additive, the "adsorption-reaction-film formation" lubrication mechanism is proposed. IOMo forms strongly adsorbed ultra-thick adsorption film on the friction pair surface through electrostatic adsorption, effectively avoiding the running-in wear stage. During the friction process, frictional chemical reactions facilitate the formation of a complex boundary lubrication film, thereby demonstrating excellent anti-friction and anti-wear capabilities across the entire lubrication range.