Tribo-Film Formation of Lubricant Additives on Cr-Plated Surface Sliding Against Nitrile-Butadiene Rubber

摘要

A Bowden and Leben type sliding tester was used with a base oil to evaluate four types of friction modifier additives - acid phosphate, hydrogen phosphite, acid phosphate amine salt, and amine - as a fundamental study on hydraulic fluid additives for sliding of nitrile-butadiene rubber on Cr-plated metal. Acid phosphate showed the lowest friction coefficient among the phosphorus acids. After the sliding test, the formation of tribo-films on the Cr-plated surface was investigated by Fourier transform infrared reflection absorption spectroscopy and a time-of-flight secondary ion mass spectrometer. The analytical results suggest that tribo-films formed by the phosphorus acids effectively reduced friction.