The interrelation between mechanical properties, corrosion resistance and microstructure of Pb–Sn casting alloys for lead-acid battery components

It is well known that there is a strong influence of thermal processing variables on the solidification structure and as a direct consequence on the casting final properties. The morphological microstructural parameters such as grain size and cellular or dendritic spacings will depend on the heat transfer conditions imposed by the metal/mould system. There is a need to improve the understanding of the interrelation between the microstructure, mechanical properties and corrosion resistance of dilute Pb–Sn casting alloys which are widely used in the manufacture of battery components. The present study has established correlations between cellular microstructure, ultimate tensile strength and corrosion resistance of Pb–1 wt% Sn and Pb–2.5 wt% Sn alloys by providing a combined plot of these properties as a function of cell spacing. It was found that a compromise between good corrosion resistance and good mechanical properties can be attained by choosing an appropriate cell spacing range.