Laser marking of raw anode foil to induce uniform pattering and etching with oxide passivation mask

Abstract

A method of producing an electrode for use in the manufacture of electrolytic capacitors for implantable cardioverter defibrillators comprises first growing a hydrate layer and/or formed oxide layers of the foil, applying a laser beam to portions of the foil to ablate the aluminum oxide foil surface before etching in order to induce etching in the specific areas, and then, etching the foil. The laser marks the oxide layer in a pulsed spot pattern through the hydrate layer and/or formed oxide layer leaving a dimpled nascent aluminum surface. The oxide layer left behind is a mask and the fresh aluminum areas are the high etching activation sites. After marking the aluminum oxide foil surface, the foil may be electrochemically etched in an electrolyte containing chloride and/or various oxidative species.

Dependencies are inferred from the claim text.