Electrochemical study of the corrosion rate of carbon steel in soil: Evolution with time and determination of residual corrosion rates under cathodic protection

摘要

Steel coupons were buried in soil boxes for 2.5 months, with or without cathodic protection. A soil from the field was used and moistened by demineralized water or 5 g L~(-1) Na_2SO_4 solution. Instantaneous corrosion rates were deduced from voltammetry experiments while average values were obtained by weight loss measurements. A detailed analysis of the polarization curves led to an estimation of residual corrosion rates (τ_(rc)) of coupons under cathodic protection. This residual phenomenon could be followed with time and it was observed that τ_(rc) decreased down to ~10 μm yr~(-1). Cathodic protection could be optimised with this methodology.