The Influence of Copper-Containing Additives on Oil Oxidation and Corrosion

The effects of transition metals in either catalyzing or inhibiting oil oxidation in the liquid phase have been extensively reported in the literature. However, little attention has been paid to the surface films formed as by-products of these reactions. In this paper, the authors investigated surface films for the important case of copper-containing additives influencing the oxidation of oil that contacts a steel surface. Copper naphthenate in solution was found to inhibit oil oxidation and to form copper-containing precipitates and deposits on the steel surface. The surface films formed were characterized by X-ray photoelectron spectroscopy, Auger spectroscopy and scanning electron microscopy. The precipitates showed a unique morphology of spherical particles several microns in diameter. A high level of copper naphthenate was found to prevent corrosion of the steel surface. Presented at the 48th Annual Meeting in Calgary, Alberta, Canada May 17-20, 1993