Corrosion of copper in sulfuric acid solutions

• Ya.G. Avdeev, A.K. Mitrushonkova and T.E. Andreeva

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia

Abstract: Some regularities of metallic copper corrosion in H2SO4 solutions were examined, including corrosion in media containing Cu(II) sulfate and Fe(III) sulfate. Analysis of the E–pH diagram for the Cu–H₂O–SO₄^2- system makes it possible to obtain important information about the possible chemical reactions that can occur during the corrosion of copper in these media and the resulting reaction products. Corrosion rates of copper M1 in H₂SO₄ solutions (20±2℃) were determined from weight loss data for metal samples in the aggressive environment for various exposure times and acid concentrations. The maximum observed corrosion rate of the metal in 2 M H₂SO₄ after 0.25 days of testing was 0.16 g/(m²∙h). After prolonged exposure of copper to 2 M H₂SO₄ (12 days), the corrosion mass loss reached 18 g/m². It was shown that the addition of CuSO₄ to 2 M H₂SO₄ affects the corrosion rate of metallic copper in different ways. Copper corrosion is accelerated at low CuSO₄ concentration (C(CuSO₄)=0.01 M). In contrast, the addition of 0.02–0.1 M CuSO₄ reduces the corrosion of metallic copper. The addition of Fe₂(SO₄)₃ to H₂SO₄ solutions significantly accelerates copper corrosion. This effect is observed at various times of contact between the metal samples and the aggressive medium. This regularity should be taken into account for industrial conditions where H₂SO₄ process solutions contaminated with Fe₂(SO₄)₃ come into contact with copper equipment.

Keywords: acid corrosion, copper, sulfuric acid, copper(II) sulfate, iron(III) sulfate

Int. J. Corros. Scale Inhib., 2025, 14, no. 4, 2155-2167
doi: 10.17675/2305-6894-2025-14-4-22

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