A High‐Efficiency Anode for Alkaline Tin‐Plating: The Effect of Alloying Constituents on the Anodic Behavior of Tin in Alkaline Stannate Solutions

Abstract

By incorporating up to about 1 per cent of aluminum in the tin anodes used in alkaline tin plating, the current densities obtainable can be markedly increased. The effect of twenty‐six elements upon the anode behavior of tin in alkaline solutions has been studied. Many have little effect in the quantities tested, i.e., up to about 1 per cent; some, such as nickel, silver, cadmium, and indium have a strong passivating action. Among the several which tend to increase anode efficiency, aluminum appears most promising from a practical standpoint, since it alloys smoothly and easily with tin, is nonpoisonous, cheap, produces no observable deleterious effect on the bath, and forms alloys which are stable and of good mechanical properties.This investigation placed principal emphasis upon the potassium stannate bath, but enough work was done with the sodium stannate solution to show that the benefits of the aluminum alloy are common to both.