Electrochemical Corrosion Probe for High Resistivity Hydrocarbon/Water Mixtures^☆

Laboratory electrochemical corrosion rate measurements have been made in highly resistive mixtures of water in hydrocarbon liquids (e.g., crude oil) using a probe with flush-mounted measuring electrodes in a coplanar configuration. The effect of the high solution resistance between the reference and working electrodes is eliminated by chemically modifying the dielectric surface between the electrodes to make it ionically conductive. This allows corrosion rates to be measured using linear polarization techniques in hydrocarbon-continuous environments of water dispersed in the liquid hydrocarbon within a heated, pressurized autoclave. Good correspondence is found between electrochemical and coupon weight loss corrosion rates. Other electrochemical corrosion tests, such as potentiodynamic polarization, have also been successfully conducted in the hydrocarbon/water mixtures.