US3406107A - Non-cyanide silver plating bath - Google Patents

Non-cyanide silver plating bath Download PDF

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Publication number
US3406107A
US3406107A US416594A US41659464A US3406107A US 3406107 A US3406107 A US 3406107A US 416594 A US416594 A US 416594A US 41659464 A US41659464 A US 41659464A US 3406107 A US3406107 A US 3406107A
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United States
Prior art keywords
silver
cyanide
bath
silver plating
plating bath
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Expired - Lifetime
Application number
US416594A
Inventor
Kurt R Grebe
John V Powers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
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International Business Machines Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to US416594A priority Critical patent/US3406107A/en
Priority to GB43989/65A priority patent/GB1047789A/en
Priority to FR40396A priority patent/FR1455680A/en
Priority to DEJ29497A priority patent/DE1247113B/en
Application granted granted Critical
Publication of US3406107A publication Critical patent/US3406107A/en
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    • 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
    • C25D3/46—Electroplating: Baths therefor from solutions of silver

Definitions

  • a non-cyanide silver plating bath is described.
  • the bath is composed of ammonium phosphate, sodium phosphate and silver nitrate.
  • Silver films deposited from the above bath are mirror bright, ductile and have excellent adhesive properties with respect to the substrates upon which the films are deposited.
  • This invention relates to the electrodeposition of silver, and more particularly to the improved electrodeposits of silver employing soluble or insoluble anodes.
  • cyanide silver plating baths are commercially feasible, they have the defect of being poisonous and must be operated under highly controlled conditions. Attempts have been made to obtain non-cyanide silver plating baths to avoid employing a dangerous or noxious substance in such baths, but such non-cyanide silver plating baths have been inefiicient to the point of making them of questionable value in a commercial operation.
  • a further object is to obtain a non-cyanide plating bath having good throwing power and whose cathode efiiciency is approximately 100%.
  • the new bath comprises ammonium phosphate, sodium phosphate, silver nitrate, all dissolved in water.
  • a representative bath would comprise 20 grams of ammonium phosphate, 100 grams of sodium phosphate, grams of silver nitrate and suflicient water to make 1 liter of the solution.
  • the bath is maintained at a temperature between 2595 C., should have a pH of 8.5 or higher and the current density of the electrodes in the bath should be -45 ma./sq. inch.
  • the ammonium phosphate is a source of ammonium ions, the latter serving to complex the silver.
  • the representative solution shows a ratio of ammonium phosphate to silver nitrate of 2: 1, the ratio of ammonium phosphate to silver nitrate can be made as high as 10:1 without interferring with the efliciency of the non-cyanide silver plating bath.
  • the ratio of sodium phosphate to silver nitrate is 10:1, such ratio can be altered to be as high as 40 or 50:1 without interfering with the operation of the plating bath. Since the sodium phosphate is employed to add to the conductivity of the electroplating solution there is a wide variation in the amount of sodium phosphate permitted. Although a temperature range of 25 95 C. is suggested, optimum depositions are obtained at about 35 C.
  • the non-cyanide silver plating solution described above has been found to be exceedingly stable wherein long shelf storage has not appreciably altered the brightness, nor ductility nor adhesive qualities of the bath.
  • the silver deposits have been found to be in an unstressed condition and the extremely good throwing power of such plating solution has made it highly desirable for plating irregularly shaped objects.
  • noncyanide silver plating bath having the following composition:
  • a non-cyanide bath for electroplating silver consisting of essentially of 20100 g./ l. of ammonium phosphate, from -500 g./1. of sodium phosphate, from 1050 g./l. of silver nitrate, the balance water, said bath having a pH of 8.5 or higher.
  • a low temperature non-cyanide bath for electroplating silver consisting of:
  • Ammonium phosphate "grams" 20 Sodium phosphate do 100 Silver nitrate do 10 Water liters 51 References Cited UNITED STATES PATENTS 744,170 11/1903 Darlay 20446 X 923,864 6/ 1909 Levy 20446 XR 2,504,272 4/1950 McCoy 20446 FOREIGN PATENTS 939,007 10/ 1963 Great Britain.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)

Description

United States Patent 3,406,107 NON-CYANIDE SILVER PLATING BATH Kurt R. Grebe, Beacon, and John V. Powers, Sheuorock,
N.Y., assignors to International Business Machines Corporation, Armonk, N.Y., a corporation of New York No Drawing. Filed Dec. 7, 1964, Ser. No. 416,594 2 Claims. (Cl. 20446) ABSTRACT OF THE DISCLOSURE A non-cyanide silver plating bath is described. The bath is composed of ammonium phosphate, sodium phosphate and silver nitrate. Silver films deposited from the above bath .are mirror bright, ductile and have excellent adhesive properties with respect to the substrates upon which the films are deposited.
This invention relates to the electrodeposition of silver, and more particularly to the improved electrodeposits of silver employing soluble or insoluble anodes.
It is very desirable in the art of electroplating silver to avoid the use of cyanide in such baths. Although cyanide silver plating baths are commercially feasible, they have the defect of being poisonous and must be operated under highly controlled conditions. Attempts have been made to obtain non-cyanide silver plating baths to avoid employing a dangerous or noxious substance in such baths, but such non-cyanide silver plating baths have been inefiicient to the point of making them of questionable value in a commercial operation.
Consequently, it is an object of this invention to provide a non-cyanide silver plating bath that is economically feasible in its operation and competitive with cyanide silver plating baths.
It is yet another object to obtain a non-cyanide silver plating bath which has high speed in its operation, produces a mirror bright silver deposit, is extremely ductile and has excellent adhesive properties with respect to a substrate on which said silver is deposited.
It is a further object to provide a non-cyanide silver plating bath that is exceedingly stable.
A further object is to obtain a non-cyanide plating bath having good throwing power and whose cathode efiiciency is approximately 100%.
The foregoing and other objects, features and advan tages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention.
The new bath comprises ammonium phosphate, sodium phosphate, silver nitrate, all dissolved in water. A representative bath would comprise 20 grams of ammonium phosphate, 100 grams of sodium phosphate, grams of silver nitrate and suflicient water to make 1 liter of the solution. The bath is maintained at a temperature between 2595 C., should have a pH of 8.5 or higher and the current density of the electrodes in the bath should be -45 ma./sq. inch.
During the passage of current between the cathode and the anode of the electroplating bath, wherein said anode could either be soluble or insoluble, the ammonium phosphate is a source of ammonium ions, the latter serving to complex the silver. Although the representative solution shows a ratio of ammonium phosphate to silver nitrate of 2: 1, the ratio of ammonium phosphate to silver nitrate can be made as high as 10:1 without interferring with the efliciency of the non-cyanide silver plating bath. Moreover, in the example given, the ratio of sodium phosphate to silver nitrate is 10:1, such ratio can be altered to be as high as 40 or 50:1 without interfering with the operation of the plating bath. Since the sodium phosphate is employed to add to the conductivity of the electroplating solution there is a wide variation in the amount of sodium phosphate permitted. Although a temperature range of 25 95 C. is suggested, optimum depositions are obtained at about 35 C.
The non-cyanide silver plating solution described above has been found to be exceedingly stable wherein long shelf storage has not appreciably altered the brightness, nor ductility nor adhesive qualities of the bath. The silver deposits have been found to be in an unstressed condition and the extremely good throwing power of such plating solution has made it highly desirable for plating irregularly shaped objects.
According to this invention there is provided a noncyanide silver plating bath having the following composition:
While the invention has been particularly described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
What is claimed is:
1. A non-cyanide bath for electroplating silver consisting of essentially of 20100 g./ l. of ammonium phosphate, from -500 g./1. of sodium phosphate, from 1050 g./l. of silver nitrate, the balance water, said bath having a pH of 8.5 or higher.
2. A low temperature non-cyanide bath for electroplating silver consisting of:
Ammonium phosphate "grams" 20 Sodium phosphate do 100 Silver nitrate do 10 Water liters 51 References Cited UNITED STATES PATENTS 744,170 11/1903 Darlay 20446 X 923,864 6/ 1909 Levy 20446 XR 2,504,272 4/1950 McCoy 20446 FOREIGN PATENTS 939,007 10/ 1963 Great Britain.
OTHER REFERENCES American Chemical Journal, p. 335, vol. 12, 1890.
HOWARD S. WILLIAMS, Primary Examiner.
G. KAPLAN, Assistant Examiner.
US416594A 1964-12-07 1964-12-07 Non-cyanide silver plating bath Expired - Lifetime US3406107A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US416594A US3406107A (en) 1964-12-07 1964-12-07 Non-cyanide silver plating bath
GB43989/65A GB1047789A (en) 1964-12-07 1965-10-18 Electrodeposition of silver
FR40396A FR1455680A (en) 1964-12-07 1965-12-01 Silver coating bath, non-cyanide
DEJ29497A DE1247113B (en) 1964-12-07 1965-12-02 Cyanide-free galvanic silver bath

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US416594A US3406107A (en) 1964-12-07 1964-12-07 Non-cyanide silver plating bath

Publications (1)

Publication Number Publication Date
US3406107A true US3406107A (en) 1968-10-15

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US (1) US3406107A (en)
DE (1) DE1247113B (en)
FR (1) FR1455680A (en)
GB (1) GB1047789A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155817A (en) * 1978-08-11 1979-05-22 American Chemical And Refining Company, Inc. Low free cyanide high purity silver electroplating bath and method
US6027862A (en) * 1996-11-21 2000-02-22 U.S. Philips Corporation Method of applying a silver layer to a glass substrate
DE102015008686A1 (en) 2015-07-02 2017-01-05 ORU e.V. Cyanide-free, aqueous electrolytic composition

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US744170A (en) * 1899-08-26 1903-11-17 Andre Darlay Process of depositing metallic coatings on metallic objects.
US923864A (en) * 1908-02-03 1909-06-08 Alfred Levy Process for the electric dissociation of metals by the wet method.
US2504272A (en) * 1944-10-25 1950-04-18 Ewald H Mccoy Electrodeposition of silver
GB939007A (en) * 1961-01-24 1963-10-09 Sel Rex Corp Bright gold electroplating

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US744170A (en) * 1899-08-26 1903-11-17 Andre Darlay Process of depositing metallic coatings on metallic objects.
US923864A (en) * 1908-02-03 1909-06-08 Alfred Levy Process for the electric dissociation of metals by the wet method.
US2504272A (en) * 1944-10-25 1950-04-18 Ewald H Mccoy Electrodeposition of silver
GB939007A (en) * 1961-01-24 1963-10-09 Sel Rex Corp Bright gold electroplating

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155817A (en) * 1978-08-11 1979-05-22 American Chemical And Refining Company, Inc. Low free cyanide high purity silver electroplating bath and method
US6027862A (en) * 1996-11-21 2000-02-22 U.S. Philips Corporation Method of applying a silver layer to a glass substrate
DE102015008686A1 (en) 2015-07-02 2017-01-05 ORU e.V. Cyanide-free, aqueous electrolytic composition

Also Published As

Publication number Publication date
FR1455680A (en) 1966-10-14
GB1047789A (en) 1966-11-09
DE1247113B (en) 1967-08-10

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