The role of mechanical and chemical processes in anti-wear properties of ZDDP tribofilms

摘要: ZDDP additives have been used for their antiwear and antioxidant properties in lubricating systems many years. In case of boundary lubrication, this additive generates a protective solid film on the surfaces called tribofilm. This work focuses rheological durability such films. previous paper, feasibility particular experimental analysis rheology tribofilms has demonstrated. test procedure under realistic conditions (macrotribology) permits visualization quantification its durability. It consists different steps. First all, large tribofilm (6×7 mm 2 ) is generated using Cameron-Plint tribometer cylinder-on-flat configuration standard lubricated (PAO ZDDP). An aluminum mask with comb shape positioned tribofilm, which then etched an Ar + ion beam (5 keV), order to remove where does not cover sample. Finally, striped sample obtained lateral alternation zones original area (of approximately 1 width). On sample, Dual Zone Friction Test (DZFT) experiment performed. fact pin-on-flat run across strip The friction signal Electrical Contact Resistance (ECR) are plotted as function position number cycles. experiments carried out dry (open air, room temperature) ultra high vacuum results were compared. Special attention given evolution chemical composition inside track during each experiment: this, study kinetics disruption by coupling Auger Electron Spectroscopy (AES) at intervals experiment. Both mechanical mechanisms seem be involved removal processes