Nowadays, the use of solar selective absorbers is prevalent in solar applications. There is different methods for production of solar selective absorbers with desirable optical properties. one of these methods is aluminium anodizing. Anodizing was as a safe method to form coatings with excellent adhesion on aluminium substrate known. so, production of solar absorber coatings with this method uses from two vantage of enough good durability and low cost. optical properties of produced surface with this method, depends on several factors in the production process. thus it was always for attention of researchers. in the past, black anodized coatings was in solar application used.anodizing time effect on anodic film thickness and saturating pigments contents on optical and microstructural of films was experimentally evaluated. in this way, oxidic – anodic film was grown on commercial pure aluminium 1100 which has excellent conductivity in a sulfuric acid electrolyte with 160 g lit-1 density and then electrocoloring treatment with copper, tin and nickel inorganic pigments in a general procedure was down. topography of surface of coatings has been investigated using Scanning Electron Microscopy. these investigations reveal that alumina film surface is embowed with average size ranged from approximately 1-10 µm. coating type, layers thickness and morphology of surface are effective on solar absorptance.in this study a correlation between microstructural features and the optical properties of these coatings has been established and it is shown that the embowed morphology caused that the solar absorptance is increased. finally the observation of effects of anodic alumina thickness and deposition density of the inorganic pigments on spectral reflectivity was studied and efficiency of solar absorber coatings for usage in solar thermal collectors has been evaluated and so it is found that colored copper coatings in comparison with colored tin and nickel coatings have better optical properties and higher solar absorptance. Key Words Solar absorber coatings, optical properties, color anodizing, aluminium
