Tribological behavior of zinc dialkyl-dithiophosphate (ZDDP) in rapeseed oil (RO)

In order to increase the anti-wear strength of rapeseed oil (RO), Zinc dialkyl-dithiophosphate (ZDDP) as an additive is put into RO. A test based on Four-ball Machine is carried out to study the influence of ZDDP on the anti-wear peformance of RO. The chemical state of main elements on worn steel surface is presented by X-ray photoelectron spectroscopy to reveal the anti-wear mechanism of RO with ZDDP. The results show that the optimum adding amount of ZDDP is 2.0%; ZDDP can improve the extreme press and anti-wear peformance of RO. Its anti-wear mechanism is that ZDDP will be decomposited with the temperature rising, thus the polymer film that is made of phosphate, sulphate and friction polymer is formed on worn steel surface.3 tabs, 3 figs, 6 refs.