AbstractLaboratory investigations of the failure of zinc anodes in sea water have shown that the presence of iron in excess of a few parts per million is the cause. No other common impurity is important.Whilst zinc of low iron content is commercially available, difficulty has been experienced in large‐scale production of uncontaminated anodes. Search has therefore been made for elements which when alloyed with the zinc would counteract the effect of iron. It was found that small additions of aluminium to zinc containing 200 p.p.m. of iron produce permanently active anodes. It is shown that the alloying additions refine the grain size of the metal and give a smooth corrosion pattern.The combined effect of silicon and aluminium is being further investigated.