The concentration of free alkali in the solution is one of the major factors which determines the program of the polishing process when treating aluminum in an alkaline solution. Although alkali is not one of the constituents used in making up the solution. It is formed in the bath as a result of hydrolysis. As the solution is used, the concentration of free alkali rises as a result of reaction of aluminum with sodium hydrogen phosphate. The optimum of alkali in the solution is 15 – 18 gram per liter. Any variation on either side in this concentration result in a considerable reduction in the reflective obtained. The operating temperature of the solution is 90 oC. At a lower temperature anode oxidation occurs and at higher temperature there is a risk of etching of the metal surface.
See other article about Alkaline Solution and metallic impurities type of metallic coating such as on chrome plating, bright chrome plating, dull black chrome plating, white chrome plating, gold color chrome plating, silver plating, gold plating, copper plating, anodizing, aluminum anodizing, black anodized, red anodized, yellow anodized, bronze color anodized, silver anodized, gold anodized, zinc coating, galvanizing.
See other article about Alkaline Solution and metallic impurities type of metallic coating such as on chrome plating, bright chrome plating, dull black chrome plating, white chrome plating, gold color chrome plating, silver plating, gold plating, copper plating, anodizing, aluminum anodizing, black anodized, red anodized, yellow anodized, bronze color anodized, silver anodized, gold anodized, zinc coating, galvanizing.