Study the corrosion of Pb-Sb-Ag alloy in sulfuric acid solution by electrochemical methods

Abstract

In this study, Pb and Pb-Sb-Ag alloy samples were used as grid materials in lead-acid batteries and investigated for their corrosion properties in a sulfuric acid (H₂SO₄) solution (density = 1.05 g/cm³). Linear sweep voltammetry (LSV) was performed according to the ISO 17475:2005 standard, with a scan rate of 0.17 mV/s, and a potential range of ±300 mV versus the open-circuit potential. The results of the Pb-Sb-Ag alloy sample show that the corrosion current density (i_corr) of 6.0 µA/cm² (0 hours), increasing to 7.44 µA/cm² after immersing 24 hours and decreasing to 2.23 and 0.77 µA/cm² after immersing 72 and 168 hours in acid solution, respectively. The i_corr of Pb sample at (0 hours: 154.95 µA/cm²; 24 hours: 322.06 µA/cm²; 72 hours: 274.01 µA/cm², 168 hours: 58.3 µA/cm²) were higher than those of the Pb-Sb-Ag sample in the test solution. The results of the Nyquist plot of the alloy samples showed that the charge transfer resistance (R₁) and polarisation resistance (R₂) of the Pb-Sb-Ag sample were 45 times and 1150
times higher, respectively, after 24 hours of immersion in the acid solution. These results indicate that the Pb-Sb-Ag sample exhibits better corrosion resistance compared to the Pb sample.