Measurement of the Instantaneous Corrosion Rate By Means of Polarization Data

The use of polarization data in the measurement of instantaneous corrosion rates is described. Steel and cast iron specimens were tested in 3000 ohm-cm waters; potentials were measured by a multicombination meter. Potential-time studies were made on all specimens in order to determine any relationship which such studies might have to the corrosion rate. It was found that a limited empirical quantitative relationship exists between the polarization slope, ΔE/ΔI, at low current density and the corrosion rate as measured by weight loss. Such a relationship will permit a rapid empirical determination of the corrosion rates of metal specimens while they are immersed in a fresh-water environment. The effect of pH on the corrosion rate of mild steel is considered briefly. 2.3.5