The Influence of Metals on Sludge Formation

The Penn State microoxidation test was used to study the effets of metals—copper, brass, aluminum, stainless steel, lead, and low-carbon steel—on the high-temperature oxidation of two esters di-2-ethylhexyl sebacate and trimethylolpropane triheptanoate. The results demonstrate that metal corrosion and sludge formation are interrelated and are greatly accelerated by intimate contact of air, lubricant and metal surface. Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in San Francisco, California, August 18–21, 1980.