Chemistry of the Extreme Pressure Lubricant Additive Lead Naphthenate on SteelSurfaces

摘要

The adsorption and chemical reactivity of the extreme pressure (EP) oil additivelead naphthenate (Pbnp) on steel surfaces is examined with X-ray photoelectron spectroscopy. In addition, the chemical compositions of AISI 440C and 52100 steel surfaces are studied as a function of sample cleaning treatment, including solvent cleaning, and treatments with acidic and basic solutions. At room temperature, Pbnp is shown to physisorb on the iron oxide overlayer present on both steel surfaces following solvent cleaning. A chemisorbed form of Pbnp is characterized by Pb 4f peaks chemically shifted by 0.3 to 0.4 eV to lower binding energy and significantly lower intensity of the C ls feature associated with the