Overview of bearing alloy corrosion in ester base fluids

Abstract

The corrosion of soft metals in ester base fluids was studied. Leaded red brass, babbitt, lead and tin were investigated in different natural and synthetic ester base fluids. The base fluids were tested neat or with added oleic acid to model oxidation and hydrolysis. In a few experiments, water was added. The metal specimens were brought into contact with the base fluid under either static or dynamic conditions. The corrosion degree was measured both on the metal specimen (gravimetrically) and in the oil (wear metal analysis). Larger weight losses were observed for the babbitt material than for the leaded red brass. A higher corrosion rate was observed for ester base fluids with a lower hydrolytic stability. Experiments under dynamic conditions gave rise to higher rates of corrosion. Generally, higher corrosion rates were observed for high levels of added oleic acid. Additionally, a polished specimen surface seemed to promote corrosion in this work.