Microstructural analysis of new lead–acid electrode alloys

The precipitation of Pb–0.08% Ca–1.5% Sn alloys with 0.04% Ag or 0.03% Bi additions was studied by resistivity measurements and transmission electron microscopy (TEM). The addition of Ag or Bi to the Pb–Ca–Sn ternary alloys suppresses discontinuous precipitation and accelerates the formation of continuous precipitates with high coherency strain. Ag addition has a greater effect on hardening than Bi addition. TEM-energy dispersive spectroscopy (EDS) analysis confirmed that the continuous precipitates formed in Ag-supplemented alloys contain Ag in addition to Ca, Sn and Pb elements.