Micro-sensor for monitoring oils

An electrochemical sensor has been constructed for detecting changes in the electrical responses of oil/metal systems. The sensor was used to make electrochemical impedance spectroscopy (EIS) measurements and the impedance responses are compared as a function of oil additive. This work uses the base stock oil (no additives) as the baseline for comparison of the various additives. Of the four additives tested, only the metal deactivator additive was found to increase the impedance. The full formulation oil (containing all additives) displays the lowest impedance, indicating possible additive interaction. A basic Randle's circuit was used to fit the impedance data. This type of fit provides information pertaining to the properties of the bulk oil and contributions due to the interactions at the oil/metal interface