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US4307136A
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Process for the chemical deposition of gold by autocatalytic reduction
Assignee: PHIBRO-SALOMON Inc
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Filing: 1979-11-14
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Granted: 1981-12-22
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Expires: 1999-11-14
Abstract
Abstract An improvement is disclosed for the nonelectrolytic deposition of gold by autocatalytic chemical reduction of a deposition bath containing a soluble gold salt in a strongly alkaline medium by initially adding to the deposition bath an effective amount of a metal from Group III, IV or V of the periodic classification of elements in the form of a soluble salt.
Inventors
- 👤 Patrick Prost-Tournier
- 👤 Christiane Allemmoz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:12
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/42; C23C18/44
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
85 words
In a process for the nonelectrolytic deposition of gold by autocatalytic chemical reduction of a deposition bath containing a soluble gold salt in a strongly alkaline medium; the improvement which comprises adding to said bath a metal selected from the group consisting of aluminum, gallium, indium, thallium, germanium, tin, lead, arsenic, antimony and bismuth in the form of a soluble salt and at essentially the same time as said gold salt, in an amount effective to increase the deposition of gold and maintain bath stability.
Claim 2
Dependent Claim
85 words
In a process for the nonelectrolytic deposition of gold by autocatalytic chemical reduction of a deposition bath containing a soluble gold salt in a strongly alkaline medium; the improvement which comprises adding to said bath a metal selected from the group consisting of aluminum, gallium, indium, thallium, germanium, tin, lead, arsenic, antimony and bismuth in the form of a soluble salt and at essentially the same time as said gold salt, in an amount effective to increase the deposition of gold and maintain bath stability.
Claim 3
Dependent Claim
26 words
The improvement defined in claim 1 wherein the metal from Group III, IV or V is aluminum, gallium, indium, thallium, germanium, tin, arsenic, antimony or bismuth.
Claim 4
Dependent Claim
40 words
The improvement defined in claim 1 wherein the deposition bath contains a soluble gold salt in a concentration of between 0.1 and 20 g/liter and is stabilized by an alkali metal cyanate varying in concentration between 0.1 and 50 g/liter.
Claim 5
Dependent Claim
20 words
The improvement defined in claim 1 wherein the quantity of the metal present lies between 0.05 mg and 1 g/liter.
Claim 6
Dependent Claim
20 words
The improvement defined in claim 1 wherein the quantity of the metal present lies between 0.1 mg. and 5 g/liter.
Claim 7
Dependent Claim
30 words
The improvement defined in claim 1 further comprising the step of adding a buffer so that the pH of the bath is maintained at a level of at least 10.
Claim 8
Dependent Claim
24 words
The improvement defined in claim 1 further comprising the step of adding a complexing agent suitable for formation of a complex with said metal.
Claim 9
Dependent Claim
21 words
The improvement defined in claim 7 wherein the complexing agent is a sodium salt of a tri-, tetra- or pentacetic acid.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |