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
  • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt

Definitions

• This invention relates to the electrodepositlon of'nickel from aqueous acidic nickel baths.
• the object of this invention is to decrease the grain size and increase the luster and brightncss of the nickel deposit without decreasing appreciably the ductility of the plate or the current density range of the nickel bath.
• Table I are listed a number of alpha and beta unsaturated aliphatic sulfonic acids and their optimum concentrations in the nickel baths. Actually they all can be used up to saturation in the baths, that is, they do not have critical upper concentration limits.
• Th brighteners listed in Table I can be used in any type of operating acidic nickel baths with beneficial effects.
• Table II are listed by way of illustration a number of such acidic nickel baths.
• the nickel plate obtained with the alpha and beta unsaturated sulfonic acids present in the acidic baths is very fine-grained, of good color and ductile, and remarkably free from pitting. On bufied surfaces the plate obtained is as good in reflectivity and brightness as the base.
• nickel brighteners such as, for example, zinc or cadmium in a concentration of about 0.1-0.5 g./l.
• the plate obtained is brighter than with either material alone in the bath.
• the bath can tolerate larger concentrations of the zinc and cadmium than the plain bath without getting brittle, darkish, poorly adherent plate. This is also true with respect to thallous and mercuric salts in about the same concentrations.
• the impurity, copper which does not produce any appreciable brightness when present in small concentrations, but tends, instead to very readily produce dark deposits, first appearing at the lowest current densities and extending upward as the concentration or copper is increased.
• the vinyl and allyl sulfonic acids ar extremely good. That is, they are very effective for the very low current density values while at the same time being very efiective for the middle and high current density values.
• beta unsaturated aliphatic sulfonic acids e. g., allyl sulfonic acid
• alpha unsaturated sulfonic acids e. g., vinyl sulfonic acid
• the vinyl sulionic acid makes possibl a toleration of somewhat larger concentrations of materials (both inorganic and organic) which plate out preferentially to nickel and which when alone in the bath cause brittle and easily stained plate of poor color.
• the beta olefinic double bond as present in allyl sulfonic acid does exert an eilect on, or transmits an eilect to, the sulfonic group and increases its reactivity, but not as strongly as does an alpha unsaturated bond.
• the sulfonic group affects the active unsaturation characteristics of the alpha carbon double bonds more strongly than the more distant beta, that is, the beta double bonds are more strongly olefinic in character, and thus allyl sulfonic acid also exerts a brightening effect in a somewhat similar manner as does allyl alcohol, allyl amine, allyl urea, arsonic acid, and acrylic acid. The latter, however, do not increase the toleration of impurities,
• the alpha and beta unsaturated sulfonic acids can be used with beneficial effects in other acidic nickel baths, besides those listed in Table II, for example, in baths made up with nickel sulfamate allyl the naphthalene sulfonic acids, the benzene sulfonic acids, the benzene sulfonamides, the diphenyl sulfone sulfonic acids, in that the ductility of the plate and the brightness in the recesses .(low current density areas) is improved. This is especially true'if-ithe chloride concentration of such nickel baths'is above '75 g./l. NiClaGHzO.
• Mixtures of compounds of Table I can be used with beneficial eifects (improved brightness of plate) as, for example, allyl sulfonic acid with vinyl sulfonic.
• beneficial eifects improved brightness of plate
• mixtures of the compounds of Table I with aryl sulfonates, aryl sulfonamides, aryl sulfimides, aryl sulfone sulfonic acids enhance or improve the brightness of the plate.
• 0.1-.2 g./l. of o-benzoyl sulfimide with 0.1- 3 g./l. of vinyl and allyl sulfonic acids In general the nickel salts of the alpha or beta unsaturated aliphatic sulfonic acids are preferred for additions instead of the free acids in order not to alter the pH of the baths very much.
• a method for electrodepositing fine-grained, lustrous nickel comprising the step of electrodepositing fine-grained, lustrous nickel from an aqueous acid solution consisting essentially of a material selected from the group consisting of nickel chloride, nickel sulfate, a mixture of nickel sulfate and nickel chloride, a mixture of nickel REFERENCES CITED fiuoborate and nickel chloride, a mixture of nickel
• aqueous acid solution consisting essentially of a material selected from the group consisting of nickel chloride, nickel sulfate, a mixture of nickel sulfate and nickel chloride, a mixture of nickel REFERENCES CITED fiuoborate and nickel chloride, a mixture of nickel
• the following references are of record in the fiuoborate and nickel sulfate, a mixture of nickel me of this patent:

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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)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (6)

• 0
  • FR FR955898D patent/FR955898A/fr not_active Expired
• 1945
  • 1945-07-07 US US603753A patent/US2523190A/en not_active Expired - Lifetime
• 1946
  • 1946-05-02 GB GB13288/46A patent/GB611483A/en not_active Expired
• 1950
  • 1950-09-24 DE DEU622A patent/DE845732C/de not_active Expired

Patent Citations (6)

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