THE INFLUENCE OF ZINC DIALKYLDITHIOPHOSPHATE AND PHENOL ANTIOXIDANT ON THE EFFICIENCY OF UNSATURATED ANTIWEAR ADDITIVES

摘要

The aim of the work was to determine the influence of antioxidants, i.e. 2,6-ditertbuthylphenole (DBF) and zinc dialkyldithiophosphate (ZDDP) on the antiwear (AW) activity of the model lubricant, containing 1% w/w 3-allyloxy-1,2-propandiol in n-hexadecane (C16). The results have shown no negative impact of phenol antioxidant on the overall antiwear efficiency of the unsaturated additive. The other type of antioxidant (ZDDP) not only maintained the initial AW properties of the additive but also enhanced its final efficiency by 80% in comparison to the n-hexadecane containing 1% AW additive. The deposited wear products were examined by SEM/EDS and other spectral techniques, i.e. XPS, FTIR, and SIMS, which allowed the investigation of their chemical structure and the phenomena of boundary lubrication. The observed antiwear effect is associated with the establishment of the boundary layers of both organic and inorganic products formed on the lubricant-surface interface. No inhibition of oxidative processes revealed by AW additive indicates complex tribochemical conversions of a nature that is different from typical radical mechanisms.