Aggerbeck, Martin5; Canulescu, Stela2; Dirscherl, Kai6; Johansen, Villads Egede1; Engberg, Sara Lena Josefin2; Schou, Jørgen2; Ambat, Rajan7
1 Department of Mechanical Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 Optical Microsensors and Micromaterials, Department of Photonics Engineering, Technical University of Denmark4 Solid Mechanics, Department of Mechanical Engineering, Technical University of Denmark5 Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark6 Danish Fundamental Metrology7 Centre for oil and gas – DTU, Center, Technical University of Denmark
Effect of alloy composition and prior surface finish on the optical appearance of the anodised layer on aluminium alloys was investigated. Four commercial alloys namely AA1050, Peraluman 706, AA5754, and AA6082 were used for the investigation. Microstructure and surface morphology of the substrate prior to anodising were analysed using scanning electron microscopy and atomic force microscopy. The optical appearance of the anodised surface with and without sealing was investigated using a photography setup, photospectrometry and bidirectional reflectance distribution function. It was found that the roughness of the as-etched surface increases with the degree of alloying due to second phase particles making the reflection more diffused, and that the as-etched surface morphology is similar to the oxide–substrate interface after anodising. Proper polishing is achieved on hard alloys and the glossy appearance was kept for alloys of high purity. Sealing made the specular reflection of the mechanically polished specimens more distinct.
Surface and Coatings Technology, 2014, Vol 254, p. 28-41