Estimation of residual corrosion rates of steel under cathodic protection in soils via voltammetry
By M. Barbalata,D. Caron, L. Lanarde, M. Meyer, S. Fontaine, F. Castillon, J. Vittonato, Ph. Refait
Published in International Journal of Hydrogen Energy
2014
Abstract
Steel coupons were buried in soil for 2 months under cathodic protection. Their residual corrosion rates were deduced from voltammetry and weight loss measurements. In aerated soils, the current density due to O2 reduction, jK,O2, was modelled with a mixed activation -diffusion controlled kinetic. The anodic part jA of the current density j, computed as jA = j - jK,O2, obeyed Tafel law. Its extrapolation to the protection potential gave a corrosion rate (∼7 μm yr-1) consistent with that obtained from weight loss measurements. With a deficient protection, corrosion rates remained at ∼80 μm yr-1, a value given by both methods.