ELECTROLYTIC CAPACITOR, ITS MANUFACTURE, AND ELECTRODE FOIL THEREFOR

摘要

PROBLEM TO BE SOLVED: To obtain large electrostatic capacity and to assure safe operation of manufacturing by forming a titanium oxide coating film on the surface of an aluminum foil by adhering an aqueous solution of titanium-oxycarboxylic acid complex salt to the aluminum foil, and firing. SOLUTION: After an etched aluminum foil is immersed in a 0.5-10 wt.% aqueous solution of ammonium salt of titanium-citric acid complex, the foil is pulled out of the solution and is dried by keeping it as is. After then, the aluminum foil is heated at 400-660 deg.C for firing. By this firing, an oxide coating film abundantly containing rutile-type titanium oxide is formed on the surface of the aluminum foil. The process of forming the oxide coating film may be repeated several times. The aluminum foil is further treated in an aqueous solution (chemical conversion solution) containing ammonium adipate for anodization to form an aluminum electrode foil.