US3520785A - Electroplating gold and thiomalate electrolyte therefor - Google Patents
Electroplating gold and thiomalate electrolyte therefor Download PDFInfo
- Publication number
- US3520785A US3520785A US816067A US3520785DA US3520785A US 3520785 A US3520785 A US 3520785A US 816067 A US816067 A US 816067A US 3520785D A US3520785D A US 3520785DA US 3520785 A US3520785 A US 3520785A
- Authority
- US
- United States
- Prior art keywords
- gold
- thiomalate
- bath
- arsenic
- bright
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title description 15
- 239000010931 gold Substances 0.000 title description 15
- 229910052737 gold Inorganic materials 0.000 title description 15
- 239000003792 electrolyte Substances 0.000 title description 5
- 238000009713 electroplating Methods 0.000 title description 4
- NJRXVEJTAYWCQJ-UHFFFAOYSA-L 2-mercaptosuccinate Chemical compound OC(=O)CC([S-])C([O-])=O NJRXVEJTAYWCQJ-UHFFFAOYSA-L 0.000 title 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 229910052783 alkali metal Inorganic materials 0.000 description 9
- 229910052785 arsenic Inorganic materials 0.000 description 9
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- -1 alkali metal gold thiomalate Chemical class 0.000 description 7
- 239000003513 alkali Substances 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- NJRXVEJTAYWCQJ-UHFFFAOYSA-N thiomalic acid Chemical compound OC(=O)CC(S)C(O)=O NJRXVEJTAYWCQJ-UHFFFAOYSA-N 0.000 description 3
- 150000001495 arsenic compounds Chemical class 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- AGHLUVOCTHWMJV-UHFFFAOYSA-J sodium;gold(3+);2-sulfanylbutanedioate Chemical compound [Na+].[Au+3].[O-]C(=O)CC(S)C([O-])=O.[O-]C(=O)CC(S)C([O-])=O AGHLUVOCTHWMJV-UHFFFAOYSA-J 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- DJHGAFSJWGLOIV-UHFFFAOYSA-K Arsenate3- Chemical compound [O-][As]([O-])([O-])=O DJHGAFSJWGLOIV-UHFFFAOYSA-K 0.000 description 1
- JOOSFXXMIOXKAZ-UHFFFAOYSA-H [Au+3].[Au+3].[O-]C(=O)CC(S)C([O-])=O.[O-]C(=O)CC(S)C([O-])=O.[O-]C(=O)CC(S)C([O-])=O Chemical compound [Au+3].[Au+3].[O-]C(=O)CC(S)C([O-])=O.[O-]C(=O)CC(S)C([O-])=O.[O-]C(=O)CC(S)C([O-])=O JOOSFXXMIOXKAZ-UHFFFAOYSA-H 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229940000489 arsenate Drugs 0.000 description 1
- AQLMHYSWFMLWBS-UHFFFAOYSA-N arsenite(1-) Chemical compound O[As](O)[O-] AQLMHYSWFMLWBS-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000002659 electrodeposit Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- PTLRDCMBXHILCL-UHFFFAOYSA-M sodium arsenite Chemical compound [Na+].[O-][As]=O PTLRDCMBXHILCL-UHFFFAOYSA-M 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/48—Electroplating: Baths therefor from solutions of gold
Definitions
- Gold (as alkali metal gold thiomalate)-4-8 g./l.
Description
United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE Bright gold electrodeposits are obtained from an aqueous alkaline bath containing gold, added as alkali metal gold thiomalate, and a minute proportion of a soluble arsenic compound.
This application is a continuation-in-part of U.S. application Ser. No. 584,679 filed Oct. 6, 1966, of the same title, now abandoned.
This invention relates to a process and electrolyte for plating of bright gold.
Among the objects of the invention is to provide an electrolyte and process for plating bright gold.
Among other objects of the invention is to provide a process and electrolyte for plating bright 24 karat gold.
The objects of the invention are attained by dissolving a gold thiomalate complex in an alkaline solution to provide an electrolyte containing a dissolved alkali metal gold thiomalate complex, adding a minute amount of arsenic to said bath (as a soluble salt) and adjusting the pH to about to 12.
The bath is operated at a temperature of about 24- 82 C. and at a current density of 2-10 amperes/ftfi.
The arsenic is added in proportions of approximately 10 mg. to 0.12 gm. per liter of solution and can beadded in the form of any arsenic compound which is soluble in the bath at the said pH range of 10 to 12. Since the bath is alkaline, the alkali metal arsenites and the various alkali metal arsenates are well suited as the addition compounds. The arsenic can also be added to the bath in the form of the oxide or the halide in which case an alkali metal arsenite or arsenate is formed with the alkali of the bath.
Processes of electroplating metals including gold by passing an electric current through a bath containing mercapto-metal complex salts are disclosed in U.S. 3,238,112 and among the mercapto compounds which form said metal complexes, Z-mercaptosuccinic acid (thiomalic acid) is disclosed. Without the arsenic addition as disclosed in the present application, gold deposited from the alkali metal gold thiomalate complex is, at most, semi-bright when thicknesses of 100 ,u." are approached. t"-microinches) Alkali metal gold thiomalates can be made by the process described in U.S. 1,994,213 or by the process of U.S. 3,238,112.
The preferred ranges of components and conditions for obtaining bright gold deposits are as follows:
Thiomalic acid40-100 g./l. (preferably 45-52 g./l.)
Alkali hydroxide-25-60 g./l.
Gold (as alkali metal gold thiomalate)-4-8 g./l.
As (as soluble compound)-10 mg. to 0.12 g./1. (preferably 10-30 mg./l.)
3,520,785 Patented July 14, 1970 pH-l0l2 Temperature-2482 C. Current density2l0 amps/ft.
Bright gold deposits can be obtained with more than 30 mg./l. of arsenic, but the additional arsenic does not increase the brightness.
The following example is given to illustrate, in detail, a preferred embodiment of the invention, but it will be understood that the invention may be otherwise embodied within the scope of the broader claims.
EXAMPLE An aqueous solution of thiomalic acid in sufficient proportions to provide 52 g. of the acid is mixed with an aqueous solution of sodium hydroxide in sufficient proportions to provide 40 g. of NaOH. Approximately 8 g. of previously formed sodium gold thiomalate is dissolved in the resultant mix and water is added to make 1 liter. Approximately 35 mg. of sodium arsenite (or sufficient to provide about 20 mg. of As) is added to the solution. The pH of the bath is measured and adjusted to pH 11.5, if necessary, by the addition of NaOH or thiomalic acid. Products plated from the bath at a temperature of C. and current density of 2 amps/ft. (voltage 0.7) are bright in thicknesses as high as 500a" or more.
We claim:
1. An aqueous alkaline electroplating bath for the deposition of bright gold consisting essentially of the following ingredients in the proportions set forth:
Thiomalic acid-40-l00 g./l.
Alkali hydroxide25-60 g./l.
Gold (as alkali metal gold thiomalate)-4-8 g./I.
Arsenic (as a soluble compound)10 mg. to 0.12 g./l.
2. The bath of claim 1 wherein the arsenic is added in the proportion of 10-30 mg./l.
3. A process for the electroplating of bright gold comprising electrolyzing an aqueous solution containing the following ingredients in the proportions set forth:
Thiomalic acid45-52 g./l.
Alkali hydroxide2540 g./l.
Gold (as sodium gold thiomalate)6-8 g./l.
Arsenic (as a soluble compound)-l0 mg. to 0.12 g./l.
pHl0-12 at a current density of 2-10 amps/ft. and a temperature of 24-82 C.
4. The process as claimed in claim 3 wherein the arenic is present in the proportion of 10-30 mg./l.
References Cited UNITED STATES PATENTS 3,238,112 3/1966 Haslam 20446 XR 3,423,295 1/1969 Greenspan 20443 FOREIGN PATENTS 1,027,637 2/1953 France.
OTHER REFERENCES Edmund R. TheWs, Metal Finishing, pp. -85, September 1951.
Francis C. Frary, Transactions of the Electrochemical Society, vol. 23, pp. 25-97 (1913).
JOHN H. MACK, Primary Examiner G. L. KAPLAN, Assistant Examiner U.S. C1. X.R. 204-46
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81606769A | 1969-04-14 | 1969-04-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3520785A true US3520785A (en) | 1970-07-14 |
Family
ID=25219599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US816067A Expired - Lifetime US3520785A (en) | 1969-04-14 | 1969-04-14 | Electroplating gold and thiomalate electrolyte therefor |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3520785A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3833488A (en) * | 1971-08-20 | 1974-09-03 | Auric Corp | Gold electroplating baths and process |
| US3897246A (en) * | 1971-12-15 | 1975-07-29 | Amp Inc | Novel electro deposited gold; electrolyte solution to obtain the same; method for producing said gold; and products |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1027637A (en) * | 1949-11-15 | 1953-05-13 | Heraeus Gmbh W C | Process for depositing hard galvanic coatings of noble metals |
| US3238112A (en) * | 1962-07-03 | 1966-03-01 | Du Pont | Electroplating of metals using mercapto-metal complex salts |
| US3423295A (en) * | 1966-02-23 | 1969-01-21 | Engelhard Ind Inc | Gold plating |
-
1969
- 1969-04-14 US US816067A patent/US3520785A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1027637A (en) * | 1949-11-15 | 1953-05-13 | Heraeus Gmbh W C | Process for depositing hard galvanic coatings of noble metals |
| US3238112A (en) * | 1962-07-03 | 1966-03-01 | Du Pont | Electroplating of metals using mercapto-metal complex salts |
| US3423295A (en) * | 1966-02-23 | 1969-01-21 | Engelhard Ind Inc | Gold plating |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3833488A (en) * | 1971-08-20 | 1974-09-03 | Auric Corp | Gold electroplating baths and process |
| US3897246A (en) * | 1971-12-15 | 1975-07-29 | Amp Inc | Novel electro deposited gold; electrolyte solution to obtain the same; method for producing said gold; and products |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: OXY METAL INDUSTRIES CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:OXY METAL FINISHING CORPORATION;REEL/FRAME:003967/0084 Effective date: 19741220 |
|
| AS | Assignment |
Owner name: HOOKER CHEMICALS & PLASTICS CORP. Free format text: MERGER;ASSIGNOR:OXY METAL INDUSTRIES CORPORATION;REEL/FRAME:004075/0885 Effective date: 19801222 |
|
| AS | Assignment |
Owner name: OCCIDENTAL CHEMICAL CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:HOOKER CHEMICAS & PLASTICS CORP.;REEL/FRAME:004126/0054 Effective date: 19820330 |
|
| AS | Assignment |
Owner name: OMI INTERNATIONAL CORPORATION, 21441 HOOVER ROAD, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OCCIDENTAL CHEMICAL CORPORATION;REEL/FRAME:004190/0827 Effective date: 19830915 |
|
| AS | Assignment |
Owner name: MANUFACTURERS HANOVER TRUST COMPANY, A CORP OF NY Free format text: SECURITY INTEREST;ASSIGNOR:INTERNATIONAL CORPORATION, A CORP OF DE;REEL/FRAME:004201/0733 Effective date: 19830930 |