Boundary lubrication of stainless steel and CoCrMo alloy materials based on three ester-based additives

Material selection and lubricant additive development are two important aspects for engineering applications. This work explores the possibilities of three different ester-based additives (DBOP, ODOC and DOB) to generate boundary films on two corrosion and wear resistant materials, stainless steel AISI 316 (A3) and CoCrMo alloy (S21) surfaces. The tribological performance of the materials and the additives were investigated. The different performance is proved to be related to the different adsorption and reaction film on the surfaces. XPS analysis on the A3 surface further confirms that at the boundary lubrication condition, the reaction layer originates from the tribochemical reaction of the active elements in the additives with the material surfaces.