Tribological properties of the combination system of the surface modified borate and ZDDP

The tribological performances of the combination systems of the surface modified borate and ZDDP additive were investigated by using four-ball tester. The results showed that the added amount of T202 could affect on the antiwear properties of the combination systems. The synergistic effect mechanism was observed when the added amount of T202 was equal to or more than 0.5 wt%. The antiwear properties of the combination systems of the surface modified borate and T203 or T205 could produce antigenic or synergistic effect. In comparison with ZDDP additive alone, the friction coefficient of the combination systems did not reduce obviously, however, the N-containing compound addition could improve the anti-friction propeties of the combination systems of the surface modified borate and T202. X-ray photoelectron spectroscopy analysis indicated that a tribochemical mixed film was formed on the rubbing surface of the combination systems, which consisted of BON compounds, BN, phosphate, sulphides, sulphates and oxidate.