Thermogalvanic effects on the corrosion of copper in heavy brine LiBr solutions

Thermogalvanic corrosion of copper in heavy brine LiBr solutions has been investigated using a zero-resistance ammeter (ZRA). The temperature gradients between copper electrodes immersed in the same LiBr solution result in the formation of thermogalvanic cells with hot anodes, leading to high and sustained thermogalvanic currents. Copper loss rates, calculated using Faraday’s law, substantially exceed 0.025 mm year−1, a value regarded as the threshold of low corrosion rates. The effects of thermogalvanic coupling on the surface properties of the anode and the cathode have been analysed by means of electrochemical impedance spectroscopy (EIS). The results obtained in this analysis have been related to the process of copper electrodissolution in bromide media.

► Thermogalvanic corrosion negatively affects the corrosion resistance of the hot anode. ► Thermogalvanic corrosion of copper in heavy brine LiBr solutions is severe. ► The negative values of Seebeck coefficient are indicative of hot anodes. ► Seebeck coefficient was not dependent on LiBr concentration. ► EIS diagrams revealed three time constants.