Intercorrelation of surface free energy and anode capacity of aluminium alloy anodes

Surface free energies have been evaluated from Young's moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ∼ 1.47 % Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≅ 0.08 mA/cm2 current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surfacefiree energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum. (Author)