An Electrochemical Technique for Characterizing Metal-Lubricant Interfacial Reactions

Publisher Website
Google Scholar
Abstract
An AC impedance technique, in combination with an electrical property cell, was employed to measure the electrical resistance and capacitance of lubricants. A comparison of the combined surface coating plus bulk fluid resistance and capacitance values measured for different additives blended in mineral oil, demonstrated that different metal-lubricant interaction mechanisms occur. The electrical measurements indicated that additives such as the mixed alkyl acid orthophosphate (acid phosphate) reacted with the cast iron electrodes to firm reaction films, whereas oleic acid was absorbed on the electrodes. Although the implied reactivity from electrical measurement for N-oleyl-1-1,3 diaminopropane (fatty amine) is comparable to that for acid phosphate, no reaction film for the former was detected by elemental analysis.