Tin-oxide-coated anodized aluminium selective absorber surfaces I. Preparation and characterization

Abstract Selective thermal absorber surfaces have been prepared by pyrolytically depositing conducting tin oxide on nickel-pigmented anodized aluminium. The optical properties of these surfaces are discussed in terms of various film parameters. It is shown that the integrated solar absorption α and the hemispherical thermal emittance ϵ are nearly independent of the thicknesses of the coatings. The α value depends mainly on the properties of the anodic layer whereas the ϵ value only depends on the tin oxide. To obtain the best possible selectivity the nickel pigmentation of the anodic layer and the doping of the tin oxide are of importance.