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Process for Removing Coatings of Silver, Gold and Gold/Silver Alloys

IP.com Disclosure Number: IPCOM000038791D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Alberth, W: AUTHOR [+2]

Abstract

Disadvantages of known processes for removing coatings of silver, gold and gold/silver alloys are the chemical attack of the basic material and the poisonous character of the (zyanide) solutions. Etch processes have been found which do not have these disadvantages. Thus, for instance, the following solutions remove coatings of the above-mentioned materials: NaOH, Na4EDTA, H2O2 NaOH, 2.3-butanedionedioxime, H2O2 NaOH, NaSCN, H2O2 NaOH, Na4EDTA, Na2S2O8 NaOH, 2.3-butanedionedioxime, Na2S2O8 NaOH, NaSCN, Na2S2O8 without attacking the basic material, such as Pb, Fe, Co, Cd, Cu, Mg, Ni, V, Bi, Zn, Sn, Sb, or Ta. Aluminum, by contrast, is dissolved in these solutions.

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Process for Removing Coatings of Silver, Gold and Gold/Silver Alloys

Disadvantages of known processes for removing coatings of silver, gold and gold/silver alloys are the chemical attack of the basic material and the poisonous character of the (zyanide) solutions. Etch processes have been found which do not have these disadvantages. Thus, for instance, the following solutions remove coatings of the above-mentioned materials: NaOH, Na4EDTA, H2O2

NaOH, 2.3-butanedionedioxime, H2O2

NaOH, NaSCN, H2O2

NaOH, Na4EDTA, Na2S2O8

NaOH, 2.3-butanedionedioxime, Na2S2O8

NaOH, NaSCN, Na2S2O8 without attacking the basic material, such as Pb, Fe, Co, Cd, Cu, Mg, Ni, V, Bi, Zn, Sn, Sb, or Ta.

Aluminum, by contrast, is dissolved in these solutions. Examples of removing coatings of the mentioned materials are: Coating on copper 250 g/l NaOH

150 g/l Na4EDTA

as needed, H2O2 (35%)

temperature = 70 to 80@C

Coating on steel 250 g/l NaOH

150 g/l Na4EDTA

as needed, Na2S2O8

temperature = 70 to 80@C.

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