Abstract: An improved process is provided for the production of aluminum reflective material having a higher total reflectance value. The process comprises controlling the anodizing conditions of a bright rolled aluminum alloy by immersing the alloy in a DC anodizing bath containing at least 26 wt. % sulfuric acid and the anodizing sheet at a current density of at least 1.94 amperes per square decimeter (18 amperes per square foot) at a temperature of from 15.56.degree. to 27.78.degree. C. (60.degree. to 82.degree. F.) for a time period of from about 0.5 to 10 minutes to provide a coating thickness of from about 0.06 to 0.22 mils. The process permits a highly reflective surface to be formed without subjecting the aluminum to a preliminary brightening process prior to anodizing.

Abstract: The invention comprises a highly reflective anodized aluminum alloy product consisting essentially of 0.25 to 1.5 wt. % magnesium with the balance aluminum anodized in a DC anodizing bath containing at least 26% sulfuric acid at a current density of at least 18 amperes per square foot at a temperature of at least 60.degree. F.

Abstract: An improved process is provided for the production of aluminum reflective material having a higher total reflectance value. The process comprises controlling the anodizing conditions of an aluminum alloy previously subjected to a brightening process by immersing the alloy in a DC anodizing bath containing at least 26 wt. % sulfuric acid and the anodizing sheet at a current density of at least 18 amperes per square foot at a temperature of at least 60.degree. F.

Abstract: An improved process for producing a solar selective coating on aluminum comprises a preliminary treatment such as an etch or brightening followed by anodizing in phosphoric acid at a constant voltage of from 10-20 volts for a time period sufficient to provide a total current of from 90-175 coulombs per square decimeter of aluminum surface. Prior to sealing, the resultant anodized surface is subjected to a constant AC voltage coloring treatment in a concentrated metal sulfate solution containing at least 85 grams per liter of metal sulfates.