Method for producing a self-supporting metal film

A process for producing a self-supporting metal foil (40), which by virtue of its constitution has a low shearing strength and can be structured in a sharp-edged configuration,

• wherein the metal foil (40) is galvanically deposited on a rotating roller (22) which forms a cathode and which is dipped into an electrolyte bath (10) containing ions of the metal,
• an anode cage (24) is provided at a constant spacing from the roller cathode (22) and a defined adjustable dc voltage is applied during rotation of the roller cathode (22) to the roller cathode (22) and the anode cage (24) so that a given adjustable high direct current flows between the roller cathode (22) and the anode cage (24) in the electrolyte bath (10), by which direct current a metal base layer (58) is deposited on the roller cathode (22),
• at least one additional anode (32) is provided between the roller cathode (22) and the anode cage (24),
• a defined adjustable second dc voltage is applied between the roller cathode (22) and the additional anode (32) so that a given adjustable additional direct current flows between the roller cathode (22) and the additional anode (32), whereby a cauliflower structure (60) comprising the metal is deposited in firmly adhering relationship on the outside of the metal base layer (58), which is remote from the roller cathode (22),
• the metal foil (40) comprising the metal base layer (58) provided with the cauliflower structure (60) is detached from the roller cathode (22), and
• the metal foil (40) comprising the metal base layer (58) provided with the cauliflower structure (60) is rinsed and dried,
• characterized in that
• the dried metal foil (40) comprising the metal base layer (58) provided with the cauliflower structure (60) is moved through a black oxide bath (46), and
• the metal foil (40) comprising the metal base layer (58) provided with the cauliflower structure (60), subsequently to the black oxide bath (46), is rinsed and dried.