Alusuisse Technology & Management Ltd.

Paul Hanggi

Roman Fuchs

Volkmar Gillich

Walter Hotz

Interference layer which acts as a coloring surface layer on aluminum items, said layer containing an aluminum oxide layer and, deposited on this, a partially transparent layer. The aluminum oxide layer is a transparent, pore-free barrier layer produced by anodizing, of predetermined thickness d corresponding to the desired surface color of the interference layer; the thickness d of the barrier layer lies between 20 and 900 nm, and the partially transparent layer exhibits a wavelength dependent transmission .tau.(.lambda.) which is greater than 0.01 and smaller than 1. The side of the partially transparent layer facing away from the barrier layer is preferably protected from mechanical and chemical effects by an additional, transparent protective layer.

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Neuhausen, Switzerland

Paul Hanggi