Electrode Reaction Rates on Straining Aluminum-Magnesium Wires in Chloride and Sulfate Solutions

Abstract

Electrode reaction rates on aluminum‐7 weight per cent (w/o) magnesium wires exposed to chloride and sulfate solutions have been studied as a function of tensile strain rate, electrode potential, solution pH, degree of aeration, and anion concentration. An increase in rate of both anodic and cathodic reactions was observed on application of plastic strain; the increase depends on the strain rate, the anion concentration, and the degree of anodic or cathodic polarization in the chloride or sulfate solution. At electrode potentials remote from the chloride pitting potential, the difference in electrode‐reaction rates in chloride or sulfate solutions is relatively minor; as the potential approaches the pitting potential, however, the anodic rate in chloride solution becomes significantly greater than that in sulfate solution. The anodic reaction is primarily dissolution and the cathodic is hydrogen‐ion reduction.