Schering Aktiengesellschaft

Atotech Deutschland Gmbh

Manfred Dettke

Klaus Janotta

Ludwig Stein

Wolfgang Weishaupt

Jurgen Spindler

Rudolf Klein

Robert Ruther

Renate Gesemann

Robert Ruether

Falk Richter

Renate Broulik

Stable, electroless, aqueous, acidic gold bath for depositing gold and

Combination of aqueous baths for electroless gold deposition

An aqueous bath is disclosed for the galvanic deposition of uniformly rose to violet colored gold alloys and containing an alkali- or ammonium-dicyanoaurate-I, alkali copper cyanide, alkali cyanide and a bismuth compound which is a water-soluble complex compound of bismuth. Also disclosed is a method for the galvanic deposition of the alloys and employing the particular bath.

Method and bath for electrodepositing a violet-colored

Stabilized aqueous, acid gold bath, containing a dicyanogold(I)-complex, a complex former, a reducing agent and customary additives, for electroless deposition of gold onto gold and metals that are more electronegative than gold, as well as alloys of these metals, containing a salt of hydroxylamine or a hydroxylamine derivative as reducing agent and a fluoride or hydrogen fluoride as stabilizer. Preferred embodiments include the use of an alkali- or ammonium dicyanoaurate(I) as dicyanogold(I)-complex; using a salt of hydroxylamine or a hydroxylamine derivative of the general formula ##STR1## in which R.sub.1 and R.sub.2 are the same or different and represent hydrogen or alkyl of 1 to 5 carbon atoms and X represents the residue of an inorganic acid, as reducing agent; using an alkali fluoride or an alkali hydrogen fluoride as stabilizer; and a pH-value less than 3, preferably from 0.5 to 2.8.

Acid gold bath for the electroless deposition of gold

Limited surfaces areas are galvanized by depositing a metal or metal alloy from an electrolytic solution which is applied in a jet stream so as to make contact with said surface at a predetermined spot and follow the outline of the surface up to a second predetermined spot where it is detached from the surface by suction action.

Process for galvanizing limited surface areas

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Berlin, Germany

Manfred Dettke