Electrochemical Impedance Technique — A Practical Tool for Corrosion Prediction

Abstract

Electrochemical impedance (AC impedance) measurements are practical for predicting corrosion behavior. Combining this technique with small amplitude DC polarization offers a rapid method of estimating corrosion rates. Optimization of the potentiostat gain allows for the rapid estimation of very low corrosion rates. Full use of this technique in predicting corrosion behavior is achieved by using a microcomputer to control data acquisition and a mainframe computer for data analysis. Successful use of this combination to estimate low corrosion rates and to determine other types of corrosion behavior is demonstrated for several practical applications. These applications are rapid estimation of passive alloy corrosion and evaluation of inhibitors of carbon steel corrosion in neutral pH water.