Electrochemical methods for the study of corrosion in lubricant additive systems

摘要

Potentiodynamic polarization has been used to study the corrosion behaviours of mild steel and copper in solutions containing some examples of common types of lubricant additives. A variety of conditions for performing of experiments were investigated. The best results were obtained in a background solution of 0.01 M tetra-n-butylammonium perchlorate in 1:1 toluene/ethanol. The behaviour of the aforementioned metals was characterized and compared in solutions containing allyl amine, alkyl phosphite, and organic sulfides. For most solutions, corrosion and pitting potentials and corrosion rates of each metal were found to vary with the compound's concentration. Changes in the corrosivity of chemicals towards metals were monitored as a corrosion inhibitor was added to their solutions. The relative corrosion behaviour observed were consistent with the known performance of these metals in contact with lubricants containing these additives.