Validation of the Steinrath Index Predictions for the Degree of Soil Aggressiveness Toward Copper Corrosion in Soils Contaminated with Chlorides

The main goal of this study is to validate the Steinrath index predictions toward copper corrosion in two different soils (loamy and sandy), nonmodified and modified with chlorides, reaching the typical levels of seawater and Steinrath indexes varying between (−3) and (−8). Average corrosion rates between 4.5±0.3 and 124.5±0.5 μm/y showed to be in agreement with the predictions of the Steinrath index. The copper surfaces, covered with corrosion products, were analyzed by visual observation, scanning electron microscopy coupled to energy dispersive spectroscopy, powder x-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Cuprite (Cu₂O) has been identified by XRD, as the main constituent on all of the surfaces, with traces of atacamite (Cu₂(OH)₃Cl) on top of the Cu₂O layer. FTIR spectra suggest that sulfate, silicate, and/or hydroxyls are likely to be present.