US3902977A
Expired / Lapsed
US
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Gold plating solutions and method
Assignee: Engelhard Minerals and Chemicals Corp
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Filing: 1973-12-13
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Granted: 1975-09-02
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Expires: 1993-12-13
Abstract
Abstract An aqueous gold plating solution for use in depositing bright gold plating is provided, which includes an alkali gold cyanide as the gold source, a metal chelate of an iminodiacetic acid, such as the indium or nickel chelate of iminodiacetic acid, which metal codeposits in small quantities with the gold, one or more conducting salts and a buffer, to maintain said solution at a pH within the range of from about 3 to about 4.5. The aqueous gold plating solution may optionally include a metal chelate of an aminopolycarboxylic acid, such as the nickel chelate of ethylenediamine tetraacetic acid. In addition, a method of electrodepositing gold on a substrate employing the gold plating solutions described above and gold-plated substrates or articles produced thereby are also provided. A synergistic chelate combination employed in the aforedescribed gold plating solutions to produce mirror bright gold finishes is also provided, which combination includes the nickel chelate of iminodiacetic acid, the nickel chelate of ethylenediamine tetraacetic acid and the cobalt chelate of iminodiacetic acid.
Inventors
- 👤 Lawrence Greenspan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:49
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/56; C25D3/62; C25D3/48
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
102 words
AN AQUEOUS ELECTROLYTIC BATH FOR GOLD PLATING COMPRISING A GOLD CYANIDE AS A GOLD SOURCE IN AN AMOUNT TO PROVIDE A GOLD CONCENTRATION WITHIN THE RANGE OF FROM ABOUT 1 TO 24 GRAMS/LITER, A METAL CHELATE OF AN IMIMODIACETIC ACID IN AN AMOUNT TO PROVIDE A CONCENTRATION OF SAID METAL WITHIN THE RANGE OF FROM ABOUT 0.05 TO ABOUT 10 GRAMS/LITER, AT LEAST ONE ADDITIONAL CONDUCTING SALT IN AN AMOUNT WITHIN THE RANGE OF FROM ABOUT 10 TO ABOUT 150 GRAMS/LITER, AND A BUFFER TO MAINTAIN SAID ELECTROLYTIC BATH AT A PH WITHIN THE RANGE OF FROM ABOUT 3 TO ABOUT 4.5.
Claim 2
Dependent Claim
102 words
AN AQUEOUS ELECTROLYTIC BATH FOR GOLD PLATING COMPRISING A GOLD CYANIDE AS A GOLD SOURCE IN AN AMOUNT TO PROVIDE A GOLD CONCENTRATION WITHIN THE RANGE OF FROM ABOUT 1 TO 24 GRAMS/LITER, A METAL CHELATE OF AN IMIMODIACETIC ACID IN AN AMOUNT TO PROVIDE A CONCENTRATION OF SAID METAL WITHIN THE RANGE OF FROM ABOUT 0.05 TO ABOUT 10 GRAMS/LITER, AT LEAST ONE ADDITIONAL CONDUCTING SALT IN AN AMOUNT WITHIN THE RANGE OF FROM ABOUT 10 TO ABOUT 150 GRAMS/LITER, AND A BUFFER TO MAINTAIN SAID ELECTROLYTIC BATH AT A PH WITHIN THE RANGE OF FROM ABOUT 3 TO ABOUT 4.5.
Claim 3
Dependent Claim
23 words
The electrolytic bath in accordance with claim 1 wherein said metal iminodiacetic acid chelate has a stability constant of up to about 10.
Claim 4
Dependent Claim
19 words
The electrolytic bath in accordance with claim 2 wherein said metal of said metal iminodiacetic acid chelate is indium.
Claim 5
Dependent Claim
19 words
The electrolytic bath in accordance with claim 2 wherein said metal of said metal iminodiacetic acid chelate is nickel.
Claim 6
Dependent Claim
19 words
The electrolytic bath in accordance with claim 2 wherein said metal of said metal iminodiacetic acid chelate is cobalt.
Claim 7
Dependent Claim
19 words
The electrolytic bath in accordance with claim 2 wherein said metal of said metal iminodiacetic acid chelate is cadmium.
Claim 8
Dependent Claim
19 words
The electrolytic bath in accordance with claim 2 wherein said metal of said metal iminodiacetic acid chelate is zinc.
Claim 9
Dependent Claim
42 words
The electrolytic bath in accordance with claim 1, including, in addition, a metal chelate of an aminopolycarboxylic acid in an amount to provide a concentration of said metal in an amount within the range of from about 0.25 to about 15 grams/liter.
Claim 10
Dependent Claim
24 words
The electrolytic bath in accordance with claim 8 wherein said metal chelate of an aminopolycarboxylic acid is a metal chelate of ethylenediamine tetraacetic acid.
Claim 11
Dependent Claim
39 words
The electrolytic bath in accordance with claim 9 wherein said metal chelate of ethylenediamine tetraacetic acid is the nickel chelate of ethylenediamine tetraacetic acid and the metal chelate of an iminodiacetic acid is the nickel chelate of iminodiacetic acid.
Claim 12
Dependent Claim
17 words
The electrolytic bath in accordance with claim 10, including, in addition, the cobalt chelate of iminodiacetic acid.
Claim 13
Dependent Claim
18 words
The electrolytic bath in accordance with claim 10, including, in addition, the indium chelate of ethylenediamine tetraacetic acid.
Claim 14
Dependent Claim
31 words
The electrolytic bath in accordance with claim 1 wherein said gold cyanide is an alkali gold cyanide selected from the group consisting of alkali metal gold cyanides and ammonium gold cyanide.
Claim 15
Dependent Claim
117 words
The electrolytic bath in accordance with claim 13 wherein said metal chelate of iminodiacetic acid is the nickel chelate of iminodiacetic acid, said bath further comprising the nickel chelate oF ethylenediamine tetraacetic acid in an amount to provide a nickel concentration of within the range of from about 0.25 to about 10 grams/liter, and a chelate selected from the group consisting of the indium chelate of ethylenediamine tetraacetic acid in an amount to provide an indium concentration within the range of from about 0.25 to about 15 grams/liter, and the cobalt chelate of iminodiacetic acid in an amount to provide a cobalt concentration within the range of from about 0.05 to about 10 grams/liter, and mixtures thereof.
Claim 16
Dependent Claim
21 words
The electrolytic bath in accordance with claim 14 wherein said conducting salt comprises a water-soluble ammonium salt or alkali metal salt.
Claim 17
Dependent Claim
16 words
The electrolytic bath in accordance with claim 14 wherein said buffer comprises a weak organic acid.
Claim 18
Dependent Claim
16 words
The electrolytic bath in accordance with claim 13 wherein said alkali gold cyanide is potassium aurocyanide.
Claim 19
Dependent Claim
21 words
The electrolytic bath in accordance with claim 1 wherein said metal chelate is prepared from an iminodiacetic acid having the formula
Claim 20
Dependent Claim
12 words
The electrolytic bath in accordance with claim 18 wherein R is hydrogen.
Claim 21
Dependent Claim
12 words
The electrolytic bath in accordance with claim 18 wherein R is methyl.
Claim 22
Dependent Claim
27 words
The electrolytic bath in accordance wtih claim 1 wherein said buffer is present in an amount within the range of from about 5 to about 200 grams/liter.
Claim 23
Dependent Claim
52 words
A method of electroplating gold, which comprises electrolyzing an aqueous solution having a pH within the range of from about 3 to about 4.5 comprising the aqueous electrolytic bath as defined in claim 1, to form an electroplated coating of gold and said metal of said metal chelate of an iminodiacetic acid.
Claim 24
Dependent Claim
42 words
The method in accordance with claim 22 wherein said aqueous electrolytic bath further includes a metal chelate of an aminopolycarboxylic acid in an amount to provide a concentration of said metal within the range of from about 0.25 to about 15 grams/liter.
Claim 25
Dependent Claim
23 words
The method in accordance with claim 23 wherein said metal chelate of an aminopolycarboxylic acid comprises the nickel chelate of ethylenediamine tetraacetic acid.
Claim 26
Dependent Claim
76 words
The method in accordance with claim 24 wherein said electrolytic bath further includes a chelate selected from the group consisting of the cobalt chelate of iminodiacetic acid in an amount to provide a cobalt concentration within the range of from about 0.05 to about 10 grams/liter, and the indium chelate of ethylenediamine tetraacetic acid in an amount to provide an indium concentration within the range of from about 0.25 to about 15 grams/liter, and mixtures thereof.
Claim 27
Dependent Claim
32 words
The method in accordance with claim 22 wherein said metal chelate of an iminodiacetic acid is selected from the group consisting of the nickel or indium chelate of iminodiacetic acid mixtures thereof.
Claim 28
Dependent Claim
43 words
The method in accordance with claim 22 wherein said metal chelate of an iminodiacetic acid is selected from the group consisting of the cobalt chelate of iminodiacetic acid, the zinc chelate of iminodiacetic acid, the cadmium chelate of iminodiacetic acid, and mixtures thereof.
Claim 29
Dependent Claim
183 words
An aqueous electrolytic bath for gold plating comprising a gold cyanide as a gold source in an amount to provide a gold concentration within the range of from about 1 to about 24 grams/liter, said gold cyanide comprising ammonium aurocyanide or potassium aurocyanide, a metal chelate of an iminodiacetic acid in an amount to provide a concentration of said metal within the range of from about 0.05 to about 10 grams/liter, said metal chelate of an iminodiacetic acid comprising the nickel chelate of iminodiacetic acid, at least one conducting salt in an amount within the range of from about 10 to about 150 grams/liter, said conducting salt comprising ammonium or alkali metal sulfamate, and a buffer to maintain said electrolytic bath at a pH within the range of from about 3 to about 4.5, said buffer comprising aminoacetic acid in in an amount within the range of from about 5 to about 200 grams/liter, and further including the nickel chelate of ethylenediamine tetraacetic acid in an amount to provide a nickel concentration within the range of from about 0.25 to about 10 grams/liter.
Claim 30
Dependent Claim
183 words
An aqueous electrolytic bath for gold plating comprising a gold cyanide as a gold source in an amount to provide a gold concentration within the range of from about 1 to about 24 grams/liter, said gold cyanide comprising ammonium aurocyanide or potassium aurocyanide, a metal chelate of an iminodiacetic acid in an amount to provide a concentration of said metal within the range of from about 0.05 to about 10 grams/liter, said metal chelate of an iminodiacetic acid comprising the nickel chelate of iminodiacetic acid, at least one conducting salt in an amount within the range of from about 10 to about 150 grams/liter, said conducting salt comprising ammonium or alkali metal sulfamate, and a buffer to maintain said electrolytic bath at a pH within the range of from about 3 to about 4.5, said buffer comprising aminoacetic acid in in an amount within the range of from about 5 to about 200 grams/liter, and further including the nickel chelate of ethylenediamine tetraacetic acid in an amount to provide a nickel concentration within the range of from about 0.25 to about 10 grams/liter.
Claim 31
Dependent Claim
36 words
The electrolytic bath in accordance wtih claim 28, further including the indium chelate of ethylenediamine tetraacetic acid in an amount to provide an indium concentration within the range of from about 0.25 to about 15 grams/liter.
Claim 32
Dependent Claim
35 words
The electrolytic bath in accordance with claim 28, further including the cobalt chelate of iminodiacetic acid in an amount to provide a cobalt concentration within the range of from about 0.05 to about 10 grams/liter.
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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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |