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

Definitions

• the invention relates to the electrodeposition of copper from acid baths and has for its object the formation of deposits which have a greater degree of smoothness or brilliance than is ordinarily obtained as well as deposits which are characterized by remarkable bufi'ability or capability of being buffed or "colored" by the usual bufling instrumentalities, when necessary.
• the invention is based upon the use of certaln addition agents in novel relationship and the determination of the factors affecting the action of these agents to produce most satisfactory results.
• nickel for example, very satisfactory results have been obtained by the use of nickel phosphate in amounts, for example, of about 35 grams per liter, a small amount of phosphoric acid being added also.
• non-metallic control agents we have found the most effective to be organic compounds of the class generally known as surface tension reducing or wet/ting" agents.
• wetting agents found suitable are aromatic sulphonates and a considerable number are on the market under various trade names.
• those that are useful in the acid copper sulphate bath in combination with the primary addition agents the following have been found especially beneficial:
• Triton 720 Neomerpin Tergitol 08 From the standpoint of cost. results and complete compatibility with the acid copper bath the Triton 720 has proven highly satisfactory. It is a sulphonated ether containing a branch chain and an aromatic nucleus. More specifically it is one or more compounds of the formula wherein Ar is a hydrocarbon substituted aromatic nucleus, M is a metal of the group consisting of sodium, potassium, calcium and magnesium, or is an ammonia or amine group, n is any whole numher from three to six and the hydrocarbon substituent of the aryl group has carbon atoms within the range of four to twelve. Attention is also directed to U, S. Patent 2,115.192 which discloses this known wetting agent.
• aqueous paste capable of bein poured or measured by volume and, since the amounts to be used are not critical, the paste may be added by volume, one c. c. corresponding to approximately one gram of other like agents.
• Tergitol 08 is described in literature and issued patents as being a sodium secondary alcohol sulphate.
• the neomerpin compounds are understood to be alkyl naphthalene sulphonic acids and sodium salts thereof.
• organic sulphonates that have been satisfactorily used along with thiourea in the acid copper bath, particularly in combination with the metallic additions, are di-chloro-bensene sulphonic acid, nickel benzene disulphonate. toluene sulphonic acid, naphthylamine disulphonic acid and sodium tri-isopropyl naphthalene sulphonate. These are representative of a considerable variety of aromatic sulphonates that possess similar properties and may be effectively employed. Where the wetting agent is added by weight, amounts of 0.01 to grams per liter may be used, larger amounts being generally associated with higher content of the primary addition agent.
• agents that have the function of increasing the bright-plating range For example, ammonium sulphate in amounts of 1-100 grams per liter has been found eflective.
• active-sulphur containing and represented typically by thiourea is not limited to thiourea alone.
• the class is characterized generally as containing a bivalent sulphur atom both bonds of which are directly connected to a carbon atom.
• the water soluble mercaptans for example p-dithioglycoll and thiosalicylic acid, and even some nitrogen-containing compounds not containing sulphur, as a cyanamide and particularly dicyandiamide, have also a brightening effect.
• concentrations of the cyanamide and dicyandlamide are the same as for the thiourea.
• the constitution of the bath exclusive of the novel addition agents is of standard character.
• aqueous solutions containing 125 to 250 grams per liter of the technical copper sulphate ordinarily supplied for plating and 5 to 100 grams of sulphuric acid are well known and thlourea is effective over the entire range with suitable adjustment as to plating conditions.
• the composition of the bath with reference to the content of copper sulphate and sulphuric acid is not critical within operating limits.
• the temperature of the bath for best results may vary from relatively low limits, for example, 40 F., up to near 120 F.
• the recommended temperature is (O-80 F.
• a suitable current density is 18-48 amperes per square foot of cathode area without agitation. This can be greatly increased and the brilliance improved by agitation, as by movement of the P cathodes. with rates of movement of -25 feet 7. ing
• the primary addition agent is slowly depleted during the plating operation and is to be replenished as required.
• the control or range increasign and wetting agents are apparently not depleted by plating and need replenishing only as the composition of the bath changes due to draaout or addition of fresh bath constituents.
• the baths described enable plated deposits of copper, or chiefly of copper, to be obtained which, within a certain medium range of conditions, are truly brilliant. However, even if the conditions are not so accurately maintained as to produce an entirely brilliant deposit or uniform brightness over the entire area, still the deposits are characterized by extreme fineness of crystal structure and remarkable ease of boiling to brilliance as compared with copper deposits from the ordinary acid copper baths.
• the invention is therefore of especial utility in the plating of objects of irregular contour on which a bright surface is required, as where bright deposits of nickel or chromium are to be later applied. Furthermore, by reason of the reduction in the amount and severity of the bailing operation where such may be necessary, the requirements of labor, equipment, and bufilng materials are greatly reduced and the danger of bumng through the coating is substantially eliminated.
• a bath for electrodepositing copper coman aqueous acid copper solution comprisessentially copper sulfate and sulfuric acid and having dissolved therein a compound selected from the group consisting of cyanamide and dicyandiamide, said compound having a concentration in said solution of about 0.1 gram per liter.
• a bath for electrodepositing copper comprising an aqueous acid copper solution comprising essentially copper sulfate and sulfuric acid and having dissolved therein a compound selected from the group consisting of cyanamide and dicyandiamide, said compound having a concentration in said solution within the range 0.002 to 5 grams per liter.
• a bath for electrodepositing copper comprising essentially copper sulphate and sulphuric acid and having dissolved therein cyanamide in a concentration within the range of 0.002 to 6 grams per liter.

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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)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

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ID=27014957

Family Applications (1)

Country Status (3)

Cited By (12)

Families Citing this family (6)

• 1947
  • 1947-01-17 US US722756A patent/US2489538A/en not_active Expired - Lifetime
  • 1947-07-18 GB GB19248/47A patent/GB633780A/en not_active Expired
• 1950
  • 1950-09-28 DE DEG3831A patent/DE832982C/de not_active Expired
  • 1950-09-28 DE DEG3830A patent/DE837029C/de not_active Expired

Non-Patent Citations (1)

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