Structural Hardening Mechanisms of Lead-Cadmium-Bismuth-Silver Alloys for Battery Grids

The return of equilibrium of structure state of supersaturated solid solutions of lead-cadmium-Bismuth-silver alloys has been studied by different techniques: hardness, micro-hardness, microscopy and X-ray diffraction. Two structural states were considered: raw casting alloy and rehomogenized alloy. We studied alloys Pb2%Cd1%Bi and Pb3,2%Cd2%Bi to which we added the following concentrations by weight of silver to elaborate our alloys: 0,07% Ag, 0,15% Ag, 0, 2% Ag and 0,3% Ag. The explored temperatures are: 20°C and 80°C. Overall, the influence of silver resides in a slight increase in hardness. For the alloy Pb2%Cd3%Bi0,07%Ag, the microstructure is characterized by the formation of Ag5Cd8 compound during solidification.