Swiss Aluminium Ltd.

Horst Birkmaier

Harald Severus

An object is made out of aluminum or aluminum alloy in a form such as foil, sheet, containers and the like and has a 5 to 25 .mu.m thick oxide layer produced by anodic oxidation. This oxide layer exhibits a crack-free elongation of at least 0.65 parts per thousand in the non-sealed condition and the ratio of the crack-free elongation of the oxide in the non-sealed condition to that in the colored, non-sealed condition lies between 1:1.2 and 1:5.5. Such an object can then be colored by heat-transfer printing without producing hair-line cracks in the oxide layer, which would give the image so produced an unattractive appearance.

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Neuhausen am Rheinfall, Switzerland

Horst Birkmaier