US2984603A - Platinum plating composition and process - Google Patents

Platinum plating composition and process Download PDF

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Publication number
US2984603A
US2984603A US753409A US75340958A US2984603A US 2984603 A US2984603 A US 2984603A US 753409 A US753409 A US 753409A US 75340958 A US75340958 A US 75340958A US 2984603 A US2984603 A US 2984603A
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United States
Prior art keywords
platinum
solution
concentrated
electrolyte
plating composition
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Expired - Lifetime
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US753409A
Inventor
Duva Robert
Edwin C Rinker
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.)
Occidental Chemical Corp
Sel Rex Corp
Original Assignee
Sel Rex Corp
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Filing date
Publication date
Priority to NL241990D priority Critical patent/NL241990A/xx
Priority to NL122582D priority patent/NL122582C/xx
Application filed by Sel Rex Corp filed Critical Sel Rex Corp
Priority to US753409A priority patent/US2984603A/en
Priority to GB20457/59A priority patent/GB853939A/en
Priority to FR799068A priority patent/FR1229226A/en
Priority to BE580574A priority patent/BE580574A/en
Priority to ES0251551A priority patent/ES251551A1/en
Priority to CH7643159A priority patent/CH393025A/en
Priority to DES64329A priority patent/DE1184173B/en
Application granted granted Critical
Publication of US2984603A publication Critical patent/US2984603A/en
Anticipated expiration legal-status Critical
Assigned to OXY METAL INDUSTRIES CORPORATION reassignment OXY METAL INDUSTRIES CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). 4-09-74 Assignors: OXY METAL FINISHING CORPORATION
Assigned to HOOKER CHEMICALS & PLASTICS CORP. reassignment HOOKER CHEMICALS & PLASTICS CORP. MERGER (SEE DOCUMENT FOR DETAILS). Assignors: OXY METAL INDUSTRIES CORPORATION
Assigned to OCCIDENTAL CHEMICAL CORPORATION reassignment OCCIDENTAL CHEMICAL CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE MARCH 30, 1982. Assignors: HOOKER CHEMICAS & PLASTICS CORP.
Expired - Lifetime legal-status Critical Current

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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
    • C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals

Definitions

  • This invention relates to a platinum electrolyte from which it is possible to plate thick layers of bright platinum and to the process for making the same
  • chloroplatinic acid H PtCl -6H O
  • platinum diamino dinitrite Pt(NH NO for the platinum ions.
  • the chloroplatinic acid baths though suitable for flash plating are unwieldy for heavier deposits, the deposits becoming spongy as the thickness increases.
  • the useful life of this bath is very short because of the rapid accumulation of chloride ions as the platinum is replenished.
  • Platinum diamino dinitrite also known as P-salt
  • Patent No. 1,779,436 is dissolved in an electrolyte containing ammonium hydroxide. This bath should be maintained at a temperature of 200 F. which causes a rapid loss of ammonia and a subsequent loss of electrodeposition efficiency. In order to obtain heavier than flash deposits with these baths it is necessary to re move the article from the bath from time to time, scratch brush it and only then continue the plating. These baths operate erratically, apparently due to inconsistent cathode efiiciency and occasionally cease operating altogether.
  • One phase of this invention is based on the discovery that a solution obtained by heating said P-salt in a mixture of sulfuric and phosphoric acid and mixed with water, when concentrated acids are employed, to provide an electrolyte containing at least 6 g./l. of platinum metal, can be electrolyzed to deposit bright platinum coatings on a cathode.
  • The'bbjects of the invention are attained by heating -40 g. of the platinum diamino dinitrite in about 200 cc. of an aqueous mixture comprising about 10-100 cc. of concentrated H 80 and about 10-100 cc. of concentrated H PO until dissolved, diluting the resultant composition to provide a solution containing at least about 6 g. per liter of platinum (which corresponds to about 10 g. per liter of the P-salt) and electrolyzing this solution.
  • Dilute sulfuric and/or phosphoric acid may replace the concentrated acid as long as the same amount of the acid components are added.
  • the dilute acids should have a total concentration of at least 20% of the two acids, however.
  • Example 50 cc. of concentrated H (98.+% and 50 cc. concentrated H PO are mixed with 100 cc. water and heated to about C. whereupon 20 g. of platinum diamino dinitrite are added with stirring. A certain amount of bubbles and foam form but in a short time a clear solution is obtained. It has not been possible to determine the composition of the resulting salt in the solution at the present time but it may be a fairly complex compound. The resultant solution is diluted with water to make 1 liter of solution and is then ready for electroplating.
  • the platinum is plated at a voltage of about 1 to 3 and at a current density of about 5-30 amps. per square foot.
  • the proportion of can vary from about 10:100 to about 100210 and up to about 40 g. of the P-salt can be dissolved in 20 cc. of the mixture of concentrated acids or cc. of the 20% aqueous solution of the acids.
  • the electroplating bath should have a concentration of at least about 6 g. of Pt per liter for otherwise spongy and/or dull deposits results. There is actually no limiting upper limit of Pt concentration, efficiency increases somewhat as the Pt content increases but so does the drag-out.
  • Basis metal products having a polished surface have been plated with the above solutions to thicknesses of up to 0.0002" and greater and such products retain the brightness and polish of the original surface.
  • a solution comprising water and the solution obtained by heating 10-40 g. of platinum diamino dinitrite in about 200 cc. of an aqueous mixture containing about 10-100 cc. of concentrated sulfuric acid and 10-100 cc. of concentrated phosphoric acid.
  • electrolyte as claimed in claim 1 wherein said electrolyte comprises at least about 6 g. per liter of platinum metal.
  • a process for electroplating relatively thick layers of bright platinum comprising dissolving platinum diamino dinitrite in the proportion of 10-40 g. in 200 cc. of an aqueous mixture comprising about 10-100 cc. of concentrated sulfuric acid and about 10-100 cc. of concentrated phosphoric acid, adding water to said solution to provide an aqueous solution containing at least 6 g./liter of platinum metal and electrolyzing the solution to plate out platinum therefrom.

Description

United States Patent PLATINUM PLATING COMPOSITION AND PROCESS Robert Duva, Paramus, and Edwin C. Rinker, Morristown, N.J., assiguors to Sel-Rex Corporation, Nutley, N.J., a corporation of New Jersey No Drawing. Filed Aug. 6, 1958, Ser. No. 753,409
4 Claims. (Cl. 204-47) This invention relates to a platinum electrolyte from which it is possible to plate thick layers of bright platinum and to the process for making the same Up to the present time the only commercially useful platinum plating baths have depended on chloroplatinic acid (H PtCl -6H O) or platinum diamino dinitrite Pt(NH (NO for the platinum ions. The chloroplatinic acid baths though suitable for flash plating are unwieldy for heavier deposits, the deposits becoming spongy as the thickness increases. The useful life of this bath is very short because of the rapid accumulation of chloride ions as the platinum is replenished. Platinum diamino dinitrite (also known as P-salt) which is disclosed in US. Patent No. 1,779,436 is dissolved in an electrolyte containing ammonium hydroxide. This bath should be maintained at a temperature of 200 F. which causes a rapid loss of ammonia and a subsequent loss of electrodeposition efficiency. In order to obtain heavier than flash deposits with these baths it is necessary to re move the article from the bath from time to time, scratch brush it and only then continue the plating. These baths operate erratically, apparently due to inconsistent cathode efiiciency and occasionally cease operating altogether.
Among the objects of this invention is to provide a platinum containing electrolyte suitable for plating bright platinum of relatively great thicknesses.
Among other objects of the invention is to provide a method for making the electrolyte of the invention.
One phase of this invention is based on the discovery that a solution obtained by heating said P-salt in a mixture of sulfuric and phosphoric acid and mixed with water, when concentrated acids are employed, to provide an electrolyte containing at least 6 g./l. of platinum metal, can be electrolyzed to deposit bright platinum coatings on a cathode.
The'bbjects of the invention are attained by heating -40 g. of the platinum diamino dinitrite in about 200 cc. of an aqueous mixture comprising about 10-100 cc. of concentrated H 80 and about 10-100 cc. of concentrated H PO until dissolved, diluting the resultant composition to provide a solution containing at least about 6 g. per liter of platinum (which corresponds to about 10 g. per liter of the P-salt) and electrolyzing this solution.
The following are very satisfactory operation conditions for such a bath.
Platinum metal content.. 6-20 g./liter. Sulfuric acid (conc.,
66 B.) 10-100 cc./liter. Phosphoric acid (conc.,
85%) 10-100 cc./liter. Bath container Pyrex glass. Anodes Platinum. Anode to cathode ratio..- 1 to 1 or higher. Operating temperature.. 75 to 100 C. V Current density 5 to amperes per sq. foot. Agitation rate Moderate to rapid. Electrodeposition rate 5-25 mg./ ampere minute.
Dilute sulfuric and/or phosphoric acid may replace the concentrated acid as long as the same amount of the acid components are added. The dilute acids should have a total concentration of at least 20% of the two acids, however.
The following example illustrates how the invention is put into practice.
Example 50 cc. of concentrated H (98.+% and 50 cc. concentrated H PO are mixed with 100 cc. water and heated to about C. whereupon 20 g. of platinum diamino dinitrite are added with stirring. A certain amount of bubbles and foam form but in a short time a clear solution is obtained. It has not been possible to determine the composition of the resulting salt in the solution at the present time but it may be a fairly complex compound. The resultant solution is diluted with water to make 1 liter of solution and is then ready for electroplating.
The platinum is plated at a voltage of about 1 to 3 and at a current density of about 5-30 amps. per square foot.
As indicated above the proportion of can vary from about 10:100 to about 100210 and up to about 40 g. of the P-salt can be dissolved in 20 cc. of the mixture of concentrated acids or cc. of the 20% aqueous solution of the acids. The electroplating bath should have a concentration of at least about 6 g. of Pt per liter for otherwise spongy and/or dull deposits results. There is actually no limiting upper limit of Pt concentration, efficiency increases somewhat as the Pt content increases but so does the drag-out.
Basis metal products having a polished surface have been plated with the above solutions to thicknesses of up to 0.0002" and greater and such products retain the brightness and polish of the original surface.
The features and principles underlying the invention described above in connection with specific exemplifications will suggest to those skilled in the art many other modifications thereof. It is accordingly desired that the appended claims shall not be limited to any specific feature or details thereof.
We claim:
1. As an electrolyte for plating of platinum, a solution comprising water and the solution obtained by heating 10-40 g. of platinum diamino dinitrite in about 200 cc. of an aqueous mixture containing about 10-100 cc. of concentrated sulfuric acid and 10-100 cc. of concentrated phosphoric acid.
2. The electrolyte as claimed in claim 1 wherein said electrolyte comprises at least about 6 g. per liter of platinum metal.
3. A process for electroplating relatively thick layers of bright platinum comprising dissolving platinum diamino dinitrite in the proportion of 10-40 g. in 200 cc. of an aqueous mixture comprising about 10-100 cc. of concentrated sulfuric acid and about 10-100 cc. of concentrated phosphoric acid, adding water to said solution to provide an aqueous solution containing at least 6 g./liter of platinum metal and electrolyzing the solution to plate out platinum therefrom.
4. The process as claimed in claim 3 comprising dissolving the platinum salt in the mixture of acids with the aid of heat.
References Cited in the file of this patent UNITED STATES PATENTS of of 1,779,436 Keitel Oct. 28, 1930 1,921,941 Powell et al. Aug. 8, 1933 2,027,358 Powell et a1 Jan. 7, 1936

Claims (1)

1. AS AN ELECTROLYTE FOR PLATING OF PLATINUM, A SOLUTION COMPRISING WATER AND THE SOLUTION OBTAINED BY HEATING 10-40 G. OF PLATINUM DIAMINO DINITITE IN ABOUT 200 CC. OF AN AQUEOUS MIXTURE CONTAINING ABOUT 10-100 CC. OF CONCENTRATED SULFURIC ACID AND 10-100 CC. OF CONCENTRATED PHOSPHORIC ACID.
US753409A 1958-08-06 1958-08-06 Platinum plating composition and process Expired - Lifetime US2984603A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
NL241990D NL241990A (en) 1958-08-06
NL122582D NL122582C (en) 1958-08-06
US753409A US2984603A (en) 1958-08-06 1958-08-06 Platinum plating composition and process
GB20457/59A GB853939A (en) 1958-08-06 1959-06-15 Platinum plating composition and process
FR799068A FR1229226A (en) 1958-08-06 1959-07-01 Composition for electroplating platinum
BE580574A BE580574A (en) 1958-08-06 1959-07-10 Composition for the electrolytic deposition of platinum.
ES0251551A ES251551A1 (en) 1958-08-06 1959-07-28 Platinum plating composition and process
CH7643159A CH393025A (en) 1958-08-06 1959-07-31 Method for preparing an electrolyte solution
DES64329A DE1184173B (en) 1958-08-06 1959-08-06 Bath for the galvanic deposition of thick, light platinum coatings

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US753409A US2984603A (en) 1958-08-06 1958-08-06 Platinum plating composition and process

Publications (1)

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US2984603A true US2984603A (en) 1961-05-16

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US753409A Expired - Lifetime US2984603A (en) 1958-08-06 1958-08-06 Platinum plating composition and process

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US (1) US2984603A (en)
BE (1) BE580574A (en)
CH (1) CH393025A (en)
DE (1) DE1184173B (en)
ES (1) ES251551A1 (en)
FR (1) FR1229226A (en)
GB (1) GB853939A (en)
NL (2) NL241990A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206382A (en) * 1959-09-30 1965-09-14 Johnson Matthey Co Ltd Electrodeposition of platinum or palladium
US3267009A (en) * 1962-10-08 1966-08-16 Engelhard Ind Inc Electrodeposition of platinum containing minor amounts of bismuth
US3423226A (en) * 1965-06-28 1969-01-21 Mc Donnell Douglas Corp Plating of non-metallic bodies
US3437507A (en) * 1965-07-16 1969-04-08 Mc Donnell Douglas Corp Plating of substrates
US6306277B1 (en) 2000-01-14 2001-10-23 Honeywell International Inc. Platinum electrolyte for use in electrolytic plating
US20070138019A1 (en) * 2005-12-21 2007-06-21 United Technologies Corporation Platinum modified NiCoCrAlY bondcoat for thermal barrier coating

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1431548A (en) * 1972-09-21 1976-04-07 Engelhard Ind Ltd Electrodeposition of plantinum
US4673472A (en) * 1986-02-28 1987-06-16 Technic Inc. Method and electroplating solution for deposition of palladium or alloys thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1779436A (en) * 1929-07-02 1930-10-28 Baker & Co Inc Process of electrodepositing metals of the platinum group
US1921941A (en) * 1931-03-12 1933-08-08 Johnson Matthey Co Ltd Electrodeposition of palladium
US2027358A (en) * 1931-03-12 1936-01-07 Johnson Matthey Co Ltd Electrodeposition of metals of the platinum group

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1779436A (en) * 1929-07-02 1930-10-28 Baker & Co Inc Process of electrodepositing metals of the platinum group
US1921941A (en) * 1931-03-12 1933-08-08 Johnson Matthey Co Ltd Electrodeposition of palladium
US2027358A (en) * 1931-03-12 1936-01-07 Johnson Matthey Co Ltd Electrodeposition of metals of the platinum group

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206382A (en) * 1959-09-30 1965-09-14 Johnson Matthey Co Ltd Electrodeposition of platinum or palladium
US3267009A (en) * 1962-10-08 1966-08-16 Engelhard Ind Inc Electrodeposition of platinum containing minor amounts of bismuth
US3423226A (en) * 1965-06-28 1969-01-21 Mc Donnell Douglas Corp Plating of non-metallic bodies
US3437507A (en) * 1965-07-16 1969-04-08 Mc Donnell Douglas Corp Plating of substrates
US6306277B1 (en) 2000-01-14 2001-10-23 Honeywell International Inc. Platinum electrolyte for use in electrolytic plating
US6521113B2 (en) 2000-01-14 2003-02-18 Honeywell International Inc. Method of improving the oxidation resistance of a platinum modified aluminide diffusion coating
US20070138019A1 (en) * 2005-12-21 2007-06-21 United Technologies Corporation Platinum modified NiCoCrAlY bondcoat for thermal barrier coating

Also Published As

Publication number Publication date
BE580574A (en) 1959-11-03
CH393025A (en) 1965-05-31
FR1229226A (en) 1960-09-05
ES251551A1 (en) 1959-12-16
NL241990A (en)
GB853939A (en) 1960-11-09
NL122582C (en)
DE1184173B (en) 1964-12-23

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