The tribological performance investigation of low concentrations ZDDP anti-wear additive

ZDDP is the most commonly used additive for wear reduction and prevention in commercial lubricating oil nowadays. However, this additive contains environmentally harmful phosphorus element and with zinc in its typical composition, they form the ZnP compound that blocks the pores of the catalytic converters. Developed countries such as the European Union are sensitive about the emission of vehicles and make legal arrangements in this regard due to the increase of sensitivity to the environment nowadays. In this context, the reduction of harmful substances in lubricating oils or the use of eco-friendly lubricating oil is essential. Therefore, lubricating oil manufacturers and researchers are working intensively to reduce or completely remove harmful substances in the lubricating oils in order to comply with the new regulations introduced. In this study, ZDDP, which is harmful to catalytic converters, however, very effective to prevent wear in lubricating oil, was added to a base oil such as 1, 3 and 5% in weight at low concentrations and their tribological performance was investigated by tribometer tests and surface analysis. Results show that 3% and 5% ZDDP+base oil mixtures formed effective anti-wear tribofilms on the surfaces and they can be used in lubricating oils with the close wear rates.