Patent · US Expired

Method for producing a cyanide-free solution of a gold compound that is suitable for galvanic gold baths

US6733651B1 · kind B1 · utility

2Cited by

2References

7Claims

0Family size

Assignee

W.C. Heraeus GmbH & Co. KG · DE

Inventors

Gerhard Hoffacker · Barnstorf, DE
Renate Franz · Gelnhausen, DE
Ramona Reitz · Bad Orb, DE
Richard Walter · Santa Clara, US

Key dates

Filing date	Dec 19, 2001
Grant date	May 11, 2004
Priority date	—
Expiry date	Dec 19, 2021

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC25D3/48
WIPO fieldSurface technology, coating
WIPO sectorChemistry

Abstract

A method for producing a cyanide-free solution of a gold compound that is suitable for gold electrodeposition baths. The method includes the steps of reacting at least one of a cysteine and a cysteinate with at least one of tetrachloroauric acid and a tetrachloroaurate in a first aqueous medium, separating a resulting precipitate from the first aqueous medium, and dissolving the precipitate in a second aqueous medium with elevation of the pH to 12.0-14.0.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.