Influence of differential stress on the galvanic interaction of pyrite–chalcopyrite

The effect of stress action on pyrite–chalcopyrite galvanic corrosion was investigated using polarization curves and electrochemical impedance spectroscopy (EIS) measurements. When stress increased from 0 to 4 × 105 Pa, the corrosion current density of pyrite–chalcopyrite increased from 5.678 to 6.719 μA cm−2, and the corrosion potential decreased from 281.634 to 270.187 mV, accompanied by a decrease in polarization resistance from 25.09 to 23.79 Ω·cm2. EIS results show there have three time constants in the Nyquist diagrams, which indicated the presence of different steps during the corrosion process. Stress dramatically enhanced pyrite–chalcopyrite galvanic corrosion by affecting the Cu1 − xFe1 − yS2 film and the double layer, whereas had little impact on the adsorption species. When the stress changed from 0 to 4 × 105 Pa, the pore resistance and capacitance of the Cu1 − xFe1 − yS2 film, Rp and Qp, changed by 25.72 and 72.28 %, respectively. The adsorption species resistance, Rsl, and capacitance, Qsl, only changed by 9.77 and 2.31 %, respectively.