Influence of soil conditions on corrosion behavior of buried coated and uncoated carbon steels

This paper presents an experimental investigation on influence of soil conditions on initial corrosion behavior of buried uncoated and coated steels at room temperature. Moisture contents and sodium chloride were varied in soil. The techniques used are electrochemical measurements i.e. open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization. The experimental results show that corrosion rate increases up to critical moisture content of 60 wt.% for each soil sample containing 0–10 wt.% sodium chloride. Maximum corrosion rate observed for carbon steel is 1.03 mm/yr for coupled action of 60 wt.% moisture and 5 wt.% sodium chloride. Corrosion rates of zinc-electroplated, and copper-electroplated samples are 0.45 and 0.057 mm/yr, respectively, under the same testing condition.