METHOD FOR PREPARING ALUMINUM FOIL FOR ELECTROLYTIC CAPACITOR, ALUMINUM FOIL HAVING HIGH DIELECTRIC CONSTANT, ELECTROLYTIC CAPACITOR COMPRISING SAME, AND APPARATUS FOR PREPARING ALUMINUM FOIL

摘要

The present invention relates to a method for preparing an aluminum foil for an electrolytic capacitor, an aluminum foil having a high dielectric constant, and an apparatus for preparing the aluminum foil. The preparation method comprises: an immersion step for immersing a porous aluminum foil including a plurality of etched-pores in a metal oxide sol contained in a chamber in a vacuum state; a collection step for discharging the metal oxide sol remaining in the chamber; a drying step for drying the aluminum foil coated with the metal oxide sol in a non-vacuum state; a sintering step for sintering the dried coating film; and a step for anodizing the aluminum foil with the sintered coating film formed thereon, thereby forming a composite oxide layer including an aluminum oxide layer and a metal oxide layer, which are stacked on inner wall surfaces inside the etched-pores.