Corrosion behaviour of copper containing low alloy steels in sulphuric acid

The influence of the addition of Cu on the corrosion resistance of low alloy steel in sulphuric acid was investigated using AC and DC electrochemical methods and a weight loss test, which took place in 10 wt% H2SO4 solution at room temperature. The electrochemical measurements indicated that the corrosion rate is suppressed by the addition of Cu due to a higher hydrogen overpotential and prevention of the active dissolution. Surface analyses (XPS, EPMA and SEM) of the corroded surfaces conducted after the immersion test indicated that the rust layer formed on the Cu containing steels was enriched with Cu compounds.

► Cu improved the corrosion resistance of the low alloy steels in sulfuric acid.
► Corrosion product of Cu containing steel is composed of Cu, Cu oxides and FeOOH.
► The Cu layer shows a higher hydrogen overpotential and prevention of the active dissolution.