Anti-Wear Performance and Chemical Property of Films of Nitrogen-containing Heterocyclic Lubricating Oil Additive

Abstract

Two ash-less and phosphorous-free nitrogen-containing heterocyclic anti-wear additives (N-di-isooctyl-2-benzothiazolesulfenamide, DIMB and (2-sulfurone-benzothiazole)-3-methyl-isooctyl thiohydroxy acetate, MBES) were synthesized. Their anti-wear and friction-reduction performances as lubricating oil additives in groupⅢ base oil were evaluated using SRV high temperature friction and wear tester. The chemistry of their tribofilms was analyzed with X-ray absorption near-edge spectroscopy (XANES), and atomic force microscopy (AFM) was then used to examine the general morphology of the reaction films. The results showed that the two nitrogen-containing heterocyclic compounds possess rather good anti-wear properties, but no friction-reducing performance. According to the XANES analytic results, the tribofilms generated from the additive MBES were mainly composed of FeSO4, whereas the films generated from the additive DIMB mainly contained FeS2. The AFM images revealed that in comparison with the worn surfaces from zinc dialkyldithiophosphate (ZDDP), the worn surfaces from the additives DIMB and MBES, respectively, presented large and deep grooves.