Electrochemical and Metallurgical Behavior of Lead-Magnesium Casting Alloys as Grids for Lead-Acid Batteries

Abstract

In order to evaluate the influence of magnesium on the corrosion resistance of lead anodes in H2SO4 4 M, as well as on the microcrystalline morphology of lead, different electrochemical and metallurgical studies were made, such potentiodynamique polarization, electrochemical impedance spectroscopy, microhardness evolution, X-ray fluorescence spectroscopy and optical microscopy. The obtained results have shown that the addition of magnesium up to 1.5% in weight leads to a significant decrease in the corrosion current density (Icorr) and therefore, it increases the corrosion inhibition efficiency to 83% and it reduces the famous sulfation phenomena, by facilitating the transformation of PbSO4 and PbO to PbO2. It also makes the micro-structure of Pb much stronger, which makes the Pb anodes more resistant to mechanical shocks within the battery. We have also studied the effect of temperature on the corrosion of the new casting alloys. We found that an increase in temperature led to a decrease in its effect on the corrosion of alloys, compared with that of pure lead. Therefore, the new improved battery is more resistant, durable and more environment friendly.