Superiorities of Lead-Calcium Alloys for Storage 

 Battery Construction * 



"OECENT investigations, conducted at the Bell Telephone Labora- 

 ■^^ tories and elsewhere, have demonstrated that the lead-antimony 

 alloys almost universally employed in storage cell construction are far 

 from ideal for the purpose from the electrochemical standpoint. It has 

 been shown that in the course of normal operation of the present type 

 cell, antimony is leached out of the positive electrode, passes through 

 the solution and deposits on the negative, where it promotes "local 

 action" and self-discharge. Also, it has been demonstrated that 

 stibine is generated in perceptible amounts by the present type 

 battery on over-charge. 



The continued use of lead-antimony alloys for over fifty years has 

 been due primarily to their desirable metallurgical and physical 

 characteristics and the fact that other equally satisfactory alloys of lead 

 have not been available. Electrochemical theory indicates that for 

 use in storage cell construction, lead should be alloyed only with metals 

 electronegative to it. The alloying constituents should have little 

 tendency to diffuse or segregate at the normal operating temperatures 

 reached in a cell. The resulting alloy should be considerably stronger 

 than lead, easily cast, and resistant to electrolytic corrosion. It should 

 also have high electrical conductivity and small solidification and 

 thermal contraction. 



As a result of a comprehensive investigation of lead-calcium alloys in 

 connection with cable sheathing materials, data were accumulated at 

 the Bell Telephone Laboratories which suggested the use of certain of 

 these alloys for storage battery grids and plates. Tests have been 

 conducted to determine the value of this suggestion, and with very 

 promising results. 



In the course of the cable sheath studies, the thermal equilibrium 



diagram of lead-calcium alloys containing a very small percentage of 



the calcium component was determined and is illustrated in Fig. 1. 



This diagram shows that the amount of calcium soluble in solid lead 



* Digest of Two Papers: "The Electrochemical Behavior of Lead, Lead-antimony 

 and Lead-calcium Alloys in Storage Cells" by H. E. Haring and U. B. Thomas, and 

 "Some Physical and Metallurgical Properties of Lead-calcium Alloys for Storage 

 Cell Grids and Plates" by E. E. Schumacher and G. S. Phipps. These papers are, 

 being presented before the Convention of the Electrochemical Society in Washington, 

 October, 1935, and published in the Transactions of the Society. 



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