Effect of Indium Alloying with Lead on the Mechanical Properties and Corrosion Resistance of Lead-Indium Alloys in Sulfu
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THE improvements in understanding lead/acid batteries have been started within the last 15 years. The technologies and designs of the battery will incorporate more and thinner plates with grids produced from continuous processes using stronger, more corrosionresistant grid alloys and having longer life at elevated temperature. The battery grids will become having higher utilization of active material and producing more uniform discharges.[1–4] It is well known that the alloying content plays an important role in the improvement of the battery grids properties. In this study, addition of alloying elements to Pb has been studied for a wide range of alloy compositions. The mechanical properties of alloy were improved with adding 0.03 pct calcium. Barium introduction into lead-tin-calcium alloys increases their hardness, reduces their electrochemical activity, and improves their corrosion stability.[3] More complicated role on kinetics of the formation, passivation, and growth rates of PbO and PbO2 films was obtained;[5–8] as reported by Rocca and ABDEL-RAHMAN El-SAYED and HOSSNIA S. MOHRAN, Professors, MOHAMED ISMAEL, Assistant Professor, and HODA ABDEL-SHAFY SHILKAMY, Postgradute Student, are with the Department of Chemistry, Faculty of Science, Sohag University, Sohaˆg 82524, Egypt. Contact e-mail: [email protected] ESLAM M.M. IBRAHIM, Professor, is with the Department of Physics, Faculty of Science, Sohag University, Sohaˆg 82524, Egypt. Manuscript submitted October 16, 2014. Article published online March 11, 2015 METALLURGICAL AND MATERIALS TRANSACTIONS A
Steinmetz,[9] Pb-Sn, Pb-Sb, Pb-Ca-Sn, and Pb-Ca-Sn-Sb alloys have been applied in the production of negative grids, connectors, post and strap components of both VRLA and SLI batteries.[10–13] The stability of battery grid dimensions depends on the mechanical stresses of the charge/discharge reactions with bending and stretching or wrapping. The literature survey showed that new additives have been incorporated in the grid alloy composition in order to improve its performance.[13–23] Accordingly, rare earth elements, Ag and Te, were added with the purpose of enhancing the corrosion resistance. Therefore, the battery durability at higher temperatures was improved. It is well known that the overall surface corrosion resistance of binary alloys was strongly influenced by the microstructure.[24–29] It is observed that the cooling rate imposed during solidification improves the corrosion resistance. Mukhopadhyay et al.[30] have shown that an increase in the donor density using indium will increase the conductivity of the a-PbO film, and in turn, enhance its photoconductivity. However, to best of our knowledge, using Pb-In alloys in the lead/acid battery as negative electrodes has not been yet reported. Therefore, the present work focused on the effect of In content on certain mechanical properties, e.g., microhardness, microstructural, electrochemical, and corrosion behavior of synthetic Pb-In alloys prepared in our laboratory. The results were compared with thos
