Process for Removing Coatings of Silver, Gold and Gold/Silver Alloys
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
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.