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 the electro-deposition of platinum metals and especially to the electro-deposition of metals of the group compalladous chloride (PdCl 2H O) or rhodium trichloride RhCl are preferable; to this solution I add an excess of sodium nitrite and heat until the color change indicates a reaction after which I make the hot solution ammoniacal with ammonium hydroxide.
• the sodium nitrite reacts with the metal chloride and forms a double nitrite of sodium and the metal, and upon the subsequent addition of ammonium hydroxide, as stated, an ammino nitrite of the metal is formed in solution in the ammoniacal bath and from such a bath the metal can be electrodeposited.
• the electro-deposition is done from the hot solution with a potential of 4 to 10 volts and a current of 0.05 to 0.20 amperes per square inch.
• An insoluble anode such as platinum or other precious metal, graphite, etc. may be used.
• alloys of the metals platinum, palladium and rhodium can be electrodeposited from my bath if it be prepared from ammino nitrites of the metals to be deposited.
• the preparation and use of such an alloy plating bath is analogous to the preparation and use of a single metal bath, as is more fully set forth hereinafter.
• Example I 2 grams of chloroplatinic acid were dissolved in 140 c. c. distilled water and 3 grams of sodium nitrite added. This 4 Application flied October 7, 1927. Serial Io. 224,704.
• the object to be plated was made the cathode and an anode of platinum was provided. I have found that the best results were obtained at 7 volts with a current density of 0.05 to 0.08 amperes per square inch of cathode surface while the bath is maintained at 7 5-95 C. A bright adherent plate of platinum was obtained.
• ammino nitrite solutions are especially adapted for plating the precious metals on copper, nickel, gold or alloys such as brass or white gold, and other precious metal alloys used in ewelry or scientific instruments.
• An electrolyte for the electro-deposition of a metal of the group comprising platinum, palladium and rhodium comprising the heat treated aqueous solution of a chloride of said metal and an excess of sodium nitrite containing an excess of ammonia.
• An electrolyte for the electrode -osition of a metal of the group, platinum, pa ladium and rhodium comprising an ammoniacal aqueous solution of the reaction product of a chloride of the metal with an alkali metal nitrite.
• An electrolyte for the electrodeposition of platinum comprising an ammoniacal aqueous solution of the reaction product of a chloride of platinum with an alkali metal nitrite.
• An electrolyte for the electrodeposition of platinum comprising an ammoniacal aqueous solution of the reaction product of a chloride of platinum with sodium nitrite.
• Method of preparing an electrolyte for the electrodeposition of metals of the group comprising platinum, palladium and rhodium which comprises treating an aqueous solution of a chloride of the metal to be deposited with an excess of an alkali metal nitrite until a reaction has taken place and then adding an excess of ammonia.
• Method for the preparation of an electrolyte for the electro-deposition of a. metal or alloy of the group comprising platinum, palladium and rhodium which comprises treating an aqueous solution of a chloride of said metal with an excess of sodium nitrite until a reaction has taken place and then adding an excess of ammonia.
• An electrolyte for the electrodeposition of platinum containing in solution an ammino nitrite of platinum, the electrolyte being ammoniacal.

Landscapes

• 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)
• Chemically Coating (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22842094

Family Applications (1)

Country Status (2)

Cited By (8)

• 1927
  • 1927-10-07 US US224764A patent/US1779457A/en not_active Expired - Lifetime
• 1928
  • 1928-10-05 DE DER75932D patent/DE549775C/de not_active Expired

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