Development of high performance aluminium alloy sacrificial anodes reinforced with metal oxides

Metal composites of alumina and zinc oxide were incorporated into Al + 5% Zn alloy and the reinforced alloys were used as efficient sacrificial anodes for cathodic protection of steel objects. ZnO was not only used to reinforce the alloy matrix and improve the metallurgical characteristics but also to yield effective activation of the sacrificial anodes. Galvanic efficiency as high as 83% was achieved when 0.5% ZnO was incorporated into the anode matrix. High and steady negative potential, very low polarization and substantial reduction in self-corrosion of the anodes were observed during prolonged galvanic exposure tests. However, the incorporation of alumina into the anode matrix led to an adverse effect.