Welded structures composed of aluminium alloy components are protected from white zone and exfoliation corrosion by means of a surface layer applied over the weld bead and consisting of an aluminium alloy containing 0.02 to 0.4% by weight of indium. Other elements which may be present include zinc 0.1 to 1.5%; manganese, 0.02 to 0.5%; tin, 0.12 to 0.50%; gallium, 0 to 0.2%; and magnesium, 0.01 to 6%. The surface coating may be applied by arc or flame spraying or by welding.
