| 摘要 |
PURPOSE:To make a film thinner and to decrease the radiation rate of a solar heat selective absorption film, by forming a black colored film on a base material by an electrolytic coloring method, and by removing part of an anodized film by melting treatment as an after-treatment. CONSTITUTION:An aluminum material is anodized in a water solution of sulfuric acid, phosphoric acid, oxalic acid, etc., forming an anodized film on the surface of it. Then it is electrolitically treated in the water solution containing nickel chloride, etc. Metallic constituent is separated and it fills the pores of an anodized film being formed in the above-mentioned primary process, until the absorption rate alpha reaches to the extent of saturated state. Next, a separated and colored metal 4 in the pores 3 of an anodized film 2 on the surface of an aluminum base material is an object to be treated. By dipping the object in a solution which can dissolve the anodized film 2 only without dissolving the above-mentioned separated metal 4, so that theoretically surplus anodized film part 2a only is dissolved in the solution and is removed. As for a treatment solution, phosphorous acid-chromium acid mixed solution, sodium hydroxide solution, sodium carbonate solution, etc. can be given as recommendable examples. |
