Lubricating Properties of Organic Phosphate Ester Aqueous Solutions

The lubricating properties of organic phosphate ester (DPZ) aqueous solution were investigated using the tribological testers and the home-built thin film interferometry. Experimental results indicate that DPZ can adsorb on the surfaces of rubbing pair, reduce the friction coefficient of boundary lubrication, and significantly improve the anti-seizure properties of water. Under the elastohydrodynamic lubrication (EHL), the lubricating film thickness decreases with the DPZ concentration increasing. It is thought that a preferential slip plane, which is created against the adjacent layer between the hydration sheath around the polar headgroups of DPZ molecules and bulk water, dramatically weakens the water film by breaking the H-bond network around surface.