Tribological performance and action mechanism of S-[2-(acetamido) thiazol-1-yl] dialkyl dithiocarbamate as additive in rapeseed oil

Abstract

There has been a growing concern for the use of environmentally friendly lubricants because of the worldwide interest in environmental issues. This has promoted the development of new environmentally friendly lubricants and additives. In this paper, three potential ashless additives, S-[2-(acetamido) thiazol-1-yl] dialkyl dithiocarbamate, were prepared. The tribological behavior of the synthesized compounds as additives in rapeseed oil (RO) were evaluated with a four-ball wear tester. The elemental composition and chemical nature of the antiwear film generated on steel counterfaces were investigated with electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). It was found that the synthesized compounds as additives in rapeseed oil had shown improved extreme pressure and antiwear properties and friction-reducing behavior as compared with the rapeseed oil alone. The protective film containing a reaction layer and adsorption layer was found to be formed on the wear surface. The elemental sulfur contained in the dialkyl dithiocarbamate group and thiazole group may react with counterface metal, and result in the formation of reaction films containing sulfate, organosulfur compounds and FeS 2. The nitrogen element was merely adsorbed on the lubricating surface and did not react with the metal. In addition, the polymerized ester produced by rapeseed oil also played an important role in the adsorption film.