Acid gold bath for the electroless deposition of gold

US4352690A · kind A · utility

Assignee

• SCHERING CORPORATION · US

Inventors

• Manfred Dettke · Berlin, DE
• Ludwig Stein · Berlin, DE

Key dates

• Filing date: Jul 17, 1980
• Grant date: Oct 5, 1982
• Expiry date: Jul 17, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C18/44
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

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.