Antiwear Properties and Lubrication Mechanism of Bis(N,N-dipentylcarbamothioylthio)cadmium in Mineral Oils

A bis(N,N-dipentylcarbamothioylthio)cadmium additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in mineral oil, and compared with same types of metal additives. The results show that it exhibits better anti-wear and load-carrying capacities. The surface analytical tools such as X-ray photoelectron spectrometer (XPS), Auger electron spectrometer (AES), Scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX) were used to investigate the topography, the compositions contents and the depth profile of some typical elements on the rubbing surface of worn scar. Smooth topography of worn scar further confirms that the additive showed good anti-wear capacities, the results of XPS, AES and energy dispersive X-ray analyses indicated that tribochemical mixed protective films consists of cadmium atoms, sulfides and sulphates were formed on the rubbing surface, which contribute to improve the tribological properties of lubricants. Particularly, large amounts of sulfur and cadmium atoms play an important role in improving anti-wear properties of oils