Hot corrosion resistance of a Pb–Sb alloy for lead acid battery grids

The aim of this study was to evaluate the effects of the microstructural morphologies of a Pb–6.6 wt%Sb alloy on the resulting corrosion resistance in a 0.5 M H2SO4 solution at different temperatures: environment temperature, 50 °C and 70 °C. A water-cooled unidirectional solidification system was employed permitting a wide range of microstructures to be analyzed. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the corrosion behavior of the Pb–Sb alloy samples. It was found that with increasing temperatures the general corrosion resistance of Pb–Sb dendritic alloys decreases, and that independently of the working temperature finer dendritic spacings exhibit better corrosion resistance than coarser ones.