Errors in the electrochemical evaluation of very small corrosion rates—II. Other electrochemical techniques applied to corrosion of steel in concrete

Abstract

The limitations of the Stern and Geary method for measuring corrosion rates to the charging curve analysis method, coulostatic method and determination of a.c. impedance are discussed. This last technique is compared with the linear polarization method in the case of steel embedded in concrete. It is concluded that, at present, the linear polarization method employed potentiostatically or potentio-dynamically is more accurate that the a.c. impedance method in determining the corrosion rate of steel in concrete, although the a.c. impedance may be useful for knowing the type of control of the corrosion process and the morphology of the attack. In all the techniques considered, the Tafel constants need to be obtained by other means for I corr to be calculated with accuracy.