Investigation of copper corrosion behavior subjected to power plants’ atmosphere

This study investigated the first-year corrosion behavior of copper across eight different Iranian power plants, addressing the limited existing data on copper degradation under industrial atmospheric conditions. This research incorporated meteorological data to predict atmospheric corrosion and established analytical methods, including weight loss measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD), to evaluate the stationary corrosion characteristics of copper. Empirical findings revealed that, contrary to the predictions based on ISO 9223, the actual corrosion rates of copper were significantly affected by the wind conditions and the presence of chloride ions. Accordingly, the highest corrosion rate, 3.98 μm.a⁻¹ , was recorded at the Lowshan power plant, the site with the highest wind speed, at 5.44 m.s⁻¹ . Chloride ions had a more pronounced effect on copper corrosion rates than did sulfur dioxide, even in highly polluted plants such as the Bandar-e-Abbas power plant, where the concentrations of Clˉ and SO₂ were 1150 and 234.856 mg.d⁻¹ .m⁻², respectively. Analysis of corrosion products revealed consistent formation of a double-layer on most copper coupons, comprising an inner layer of Cu₂O (with a thickness of up to 14.1 μm for the Lowshan coupon) and a thicker outer layer (with a thickness of up to 26 μm for the Bandar-e-Abbas coupon) predominantly composed of chloride compounds at coastal plants, or sulfur compounds at inland sites. Furthermore, a weak correlation was identified between the corrosion rates predicted by ISO 9223 and the empirically measured corrosion rates of copper in the studied power plant environments. • Wind speed and chloride ions strongly influenced copper atmospheric corrosion. • Cl⁻ ions had a greater impact on corrosion than SO₂, even in polluted power plants. • ISO 9223 predictions poorly correlated with measured corrosion rates.