Tribological performance and action mechanism of S-alkyl and S-benzimidazole substituted dialkyldithiocarbamates

Two new derivatives of dioctyldithiocarbamate, one containing heterocyclic group (benzimidazole) and another being an aliphatic compound, were synthes ized and characterized. Their tribological performances as lubricant additi ves in liquid paraffin were evaluated by four-ball and SRV friction and wea r testers. The results showed that S-benzimidazole substituted dioctyldithi ocarbamate (BMZ-C-8) possesses excellent tribological properties, its frict ion reducing ability and anti-wear property at high loads are comparable to that of zinc dialkyldithiophosphate (ZDDP). However, the tribological perf ormance of S-ethyl substituted dioctyldithiocarbame (HY-C-8) is worse than BMZ-C-8. The rubbed surfaces were investigated using X-ray Photoelectron Sp ectroscopy (XPS), Auger Electron Spectroscopy (AES) and Scanning Electron M icroscopy (SEM). The action mechanisms of additives were also proposed. (C) 2000 Published by Elsevier Science S.A. All rights reserved.