Polarization of 57S aluminium used as galvanic anode in 2M NaOH

Abstract

Aluminium possesses attractive properties like high energy density, high negative potential and low cost, so that it can be developed into successful galvanic anodes in primary batteries. Aluminium shows high rate of self corrosion and gassing in alkaline solutions. Incorporating inhibitors, complexing agents or addition agents in the electrolyte, can reduce self corrosion of aluminium. Formation of a zincate coating on the surface of aluminium has been tried, with a view to improve the electrochemical properties of aluminium and their alloys as galvanic anodes in primary alkaline batteries. The addition of polyaniline inhibits the corrosion of 57S aluminium in solution 2M NaOH containing 0.2M zinc oxide. From thepolarization experiements we found that the inhibitor is found to effect both anodic and cathodic processes, but anodic processes to a greater extent. the inhibition of corrosion of 57S. Aluminium in solution containing 2M NaOH, 0.2M zinc oxide and 700ppm of polymer can be attributed to the formation of protective film on the aluminium surface. From the anodic cathodic polarization study, it has been observed that 57S aluminium by immersion in 2M NaOH, containing 0.2M ZnO and 700ppm polymer is found to produce the material suitable for uses as galvanic anodes in alkaline solutions.