Process for anodizing aluminum foil

摘要

In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil and stabilization of the foil in alkaline borax baths, the foil is electrochemically anodized in an aqueous solution of monosodium phosphate having a pH of 3.5 to 5.0 as electrolyte. The anodization is interrupted for stabilization of the foil by passing it through a bath containing a borax solution having a pH of 8.5 to 9.5 at a temperature of above 80 DEG C., and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 550 V.