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
  • C25D3/38—Electroplating: Baths therefor from solutions of copper
  • C25D3/40—Electroplating: Baths therefor from solutions of copper from cyanide baths, e.g. with Cu+

Definitions

• This invention relates to electroplating copper and more particularly to the electroplating of copper from cyanide solutions.
• Excellent, adherent, dense coatings of copper are advantageously electroplated from cyanide copper solutions.
• Such solutions contain the double cyanide of copper and an alkali metal, for example copper sodium cyanide, with or without other salts andwith or without an excess of free cyanide.
• An excellent type of copper plating bath contains the double copper alkali metal cyanide in high concentration (e. g. 12 to 20 oz. per gallon of CuCN), with little or no free cyanide and a high concentration of alkali metal hydroxide.
• a difflculty sometimes experienced in electroplating copper cyanide solutions is the formation of pits in the electroplated surface. This is particularly troublesome when abright copper plating process is utilized. The formation of pits is especially apparent when a process is utilized for electroplating smooth, bright copper deposits.
• An object of the present invention is an improved method for electroplating smooth bright copper deposits. Another object is to provide means for the prevention of pitting in cyanide copper plating baths. A further object is to provide for cyanide copper plating baths certain addition agents which will prevent pitting and act as brighteners. Other objects will be hereinafter apparent.
• R R R R such as 'hydroxyl, amino and the like. These hy-.
• trimethyl-C-cetyl alpha betaine which is a siliitable addition agent, has the. following formu a:
• betaine -utilized in my invention is one in which the long chain hydrocarbon radical is substituted on the nitrogen atom as exemplified by the following:
• N-stenyl betaine Dimethyl-N-stenyl alpha betaine
• stenyl is used to designate a mixture of essentially C16 and Cm carbon length chains with some C12, C14 and C20 carbon length chains also present.
• the N-stenyl betaine is a mixture of betaines having substituted hydrocarbons of the nature indicated by the above definition of the term "stenyll The preparation of the above 'pyl, hydroxyethyl and the like.
• N-stenyl betaine and similar betainea is described in U. 8. Patent 2,129,264, Downing et al.
• Trimethyl-C-cetylalpha be- No pitting could be produced in these 501 11110115 8t 15 to 45 amps. per sq. ft.
• betaines which may be used to gamma concentration 2 m W L practice my invention are listed below by way of illustration: I cum and; Tim M Trlmethyl-C-decyl alpha betaine Mm lTrim-ethyl'c'cetyl alpha betame amps./sq it m Bdhtno m methyl-cam $33543 A2 B3- Dimethyl, beta-hydroxyethyl-C-cetyl alpha beaine Methy dubetadlydmxyethyl) t 1 alpha 20 B. Betaine concentration, 4 cc. per aal.
• the amounts of the betaines required in the copper plating solution are small and usually will not exceed about one ounce per gallon. Generally, the betaines are effective as anti-pitting agents in amounts as low as 0.01 oz. per gallon. The optimum amount will vary, depending upon the betaine used and the composition of the copper plating bath. For. electroplating copper from a copper plating bath containing 8 or more ounces per gallon of copper cyanide and sumcient alkali metal cyanide to form the copper double salt.
• the betaines are chemchemically stable in the copper cyanide ele'ctroically compatible with the various addition electrolyzing a copper sodium cyanide solution to 10 which has been added 0.02 to 0.2 ounce per gallon of trimethyl-C-cetyl alpha betaine.
• a copper plating process which comprises electrolyzing a copper sodium cyanide solution to which has been added 0.02 to 0.2 ounce per gallon of trimethyl-C-decyl alpha betaine.
• a copper plating process which comprises electrolyzing a copper sodium cyanide solution to which has-been added 0.02 to 0:2 ounce per gallon of dimethyl-N-stenyl alpha betaine.

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23146298

Family Applications (1)

Country Status (3)

Cited By (11)

Families Citing this family (1)

• 1939
  • 1939-10-02 US US297433A patent/US2255057A/en not_active Expired - Lifetime
• 1940
  • 1940-09-17 DE DEP2355D patent/DE877233C/de not_active Expired
  • 1940-11-28 FR FR867821D patent/FR867821A/fr not_active Expired

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