Patent ID: 8663752

Claim:
A manufacturing method of a carbon coated aluminum foil as a cathode of solid aluminum electrolytic capacitors comprising the steps of: A. preparing an aluminum foil by setting the aluminum foil into a chamber; B. roughening at least one surface of the aluminum foil by introducing gas into the chamber and activating an electric field so that the gas is ionized to form a plasma; positive ions in the plasma impinging against the aluminum foil that is set as a cathode of capacitors so that the surface on at least one side of the aluminum foil becomes a rough surface; and, C. depositing carbon atoms by introducing gas mixed with carbon atoms and turning on the electric field again so as to positively charge the carbon atoms, the carbon atoms with positive charge being propelled responsive to the electric field toward the aluminum foil to be embedded into the roughened surface of the aluminum foil for direct contact therewith, and accumulated on the roughened surface of the aluminum foil to form a carbon film thereon; wherein the carbon atoms and the positive ions in the plasma are directed by a bundle of magnetic fields.