OXIDISING TREATMENT OF CHEMICAL CONVERSION COATINGS

摘要

A selective absorber of solar energy employing an aluminum alloy sheet as a substrate on which a chemical conversion coating is initially formed. The coating is thereafter heat-treated into an oxidized, dark-colored coating of selective solar absorption nature. Also disclosed is a process for producing the absorber. The process comprises a chemical conversion treatment step for formation of the initial coating, and a high-temperature oxidation treatment step for final formation of the selective coating. The latter step includes preventing atmosphere in the vicinity of the substrate surface from circulating.