The corrosion behavior of copper in acid soil during soil acidification by simulated acid rain.

The corrosion behaviors of copper in acid soil during soil acidification by simulated acid rain (SAR) were studied by means of polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results indicated that the SAR increased the corrosion rate of the copper in the acidic soil. The corrosion rate of the copper increased with decreasing pH value of SAR. Corrosive characteristics of the soil obviously increased because of the leaching of the acid rain. For the leaching of the distilled water, the corrosion rate of the copper decreased. EIS of copper was a capacitive loop in the early stage of corrosion. After 60 days exposure, EIS consisted of two capacitive arcs for copper in the acidic soil leached with SAR, the control step for corrosion of copper was charge transfer process. For the distilled water, EIS consisted of a capacitive loop at higher frequency and a Warburg impedance at lower frequency, and the control step for corrosion of copper was diffusion process. [ABSTRACT FROM AUTHOR]