Method of electroforming on a metal substrate
AssigneeWestinghouse Electric Corp.
InventorsGordon A. Conn, William R. Gass
Life of this patent
Estimating the term…
Abstract
A metal article is produced by: (1) providing an aluminum master substrate, the surface of which may be smooth or patterned; (2) making the aluminum master substrate cathodic, in an acid or acid salt solution which will not etch aluminum, at a current density of between about 10 to 500A/sq. ft., at solution temperatures of up to about 50.degree.C; (3) coating the surface of the aluminum master substrate with a thin metal layer and (4) dissolving the aluminum master substrate, to provide a metal foil article that is a negative duplicate of the smooth or patterned aluminum master substrate surface.
Claims10
A method of making a metal article comprising the steps of:
- 1. providing an aluminum master substrate having at least one surface which is desired to be reproduced, said surface being covered with an oxidized layer;
- 2. making the aluminum master substrate cathodic at a current density of between about 10A/sq. ft. to about 500A/sq. ft., in an aqueous electrically conducting solution selected from the group consisting of an acid solution or acid salt solution or mixtures thereof which will not etch aluminum, said solution having a temperature of up to about 50.degree.C, said current causing evolution of gas at the solution-oxidized surface interface and chemical activation effective to thin and smooth the oxidized layer without removing it;
- 3. coating the smoothed, oxidized surface of the aluminum master substrate with a thin metal layer;
- and
- 4. dissolving the aluminum master substrate and the attached oxidized layer, to provide a metal article having a surface that is the negative duplicate of the surface of the master substrate.
A method of making a nickel article comprising the steps of:
- 1. providing an aluminum master substrate having a thickness of between about 0.001 inch to 0.25 inch and at least one surface which is desired to be reproduced, said surface being covered with a nickel oxide layer;
- 2. making the aluminum master substrate cathodic at a current density of between about 10A/sq. ft. to about 120A/sq. ft., in aqueous 2 wt. percent to 70 wt. percent nitric acid solution, said solution having a temperature of up to about 50.degree.C, said current causing evolution of gas at the solution-nickel oxide coated surface interface and chemical activation effective to thin and smooth the nickel oxide layer without removing it;
- 3. electrocoating the smoothed, nickel oxide coated surface of the aluminum master substrate by making the master substrate cathodic at a current density of between about 5A/sq. ft. to about 150A/sq. ft. in a bath containing a solution selected from the group consisting of nickel sulfamate and nickel sulfate solution for at time effective to deposit a nickel layer about 0.0002 inch to 0.050 inch thick;
- 4. dissolving the aluminum master substrate and the attached nickel oxide layer in an aqueous alkali hydroxide solution to provide a metal article having a surface that is the negative duplicate of the surface of the master substrate.
Dependencies are inferred from the claim text.