The electrochemical corrosion behavior of Sn58Bi-XCr composite solder

In this paper, the corrosion resistance of Sn58Bi-XCr (X = 0, 0.1, 0.2, 0.3 wt%) was investigated, and the electrode reaction process of the corrosion process was analyzed by electrochemical impedance spectroscopy and Tafel linear extrapolation in the strongly polarized region of the kinetic potential polarization curve. The results show that Sn58Bi-0.3Cr has the largest capacitive arc radius and Rp in the Nyquist plot. The most pronounced impedance values and phase angles appear in both the Bode mode diagram and the Bode phase diagram of the Sn58Bi-0.3Cr composite solder, indicating that the Sn58Bi-0.3Cr solder has the best corrosion resistance. Meanwhile, from the Tafel curve fitting results, as the Cr element content increases, the self-corrosion potential moves toward smaller negative values, and the corrosion current density of Sn58Bi-0.3Cr is the smallest, and the corrosion rate is the slowest, indicating the best corrosion resistance.