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
  • C25D3/30—Electroplating: Baths therefor from solutions of tin
  • C25D3/32—Electroplating: Baths therefor from solutions of tin characterised by the organic bath constituents used

Definitions

• United States Patent 6505921 U5. (:1. 2o4-s4 rm. c1. C23b 5/14, 5/46 2 Claims The invention relates to an acidic tin-depositing bath on the basis of sulphate, sulphonate or fiuoborate by means of which bright tin deposits can be obtained.
• a type of known bright tin-depositing baths contains as a brightening agent, a combination of two colloids of opposite electrical charges, for example a phenol resin and an extract of beech wood.
• a brightening agent for example a phenol resin and an extract of beech wood.
• these baths are very unstable, so that they are not suitable for practical use.
• this type of brightening agent contaminates the work pieces to a high extent so that an additional cleaning operation is required after the work piece is removed from the bath.
• acidic tin-depositing baths containing 'as a brightening agent an aromatic or heterocyclic aldehyde and, in addition, formaldehyde.
• a disadvantage of these baths is, however, that they provide bright deposits only in a very narrow range of current densities, i.e. between 5 and a./dm. This means that strongly profiled work pieces having sharp edges and small apertures, the deposition of tin on which gives rise to current density variations by a factor of even 100, cannot be covered with a uniform tin deposit of uniform gloss. The current density variations are even much larger in the case of tin deposition with the aid of drums.
• the tin-depositing baths according to the invention permit of obtaining without difficulty bright tin deposits, even on sharply profiled work pieces having sharp edges or small apertures and even in an electroplating process by means of a drum. In operation this bath allows variations in current density up to a factor 1000 without any objection. Moreover, the tinplating baths according to the invention are extremely stable.
• the acidic electroplating bath containing bivalent tin ions and, as anions, sulphate-, sulphonateor fluoborateions is characterized in accordance with the invention in that it contains as a brightening agent one or more adequately soluble compounds of the general formula:
• RrCC-Rz II II 0 wherein R is an aliphatic, aromatic, alicyclic, or heterocyclic group or a mixed aliphatic-aromatic group having, as the case may be, nonionisable substitutes or substituents not reducible in this medium, and R is hydrogen or one of the said groups or wherein the group:
• 3-R2 t t is a ring system or part of a ring system and in that, moreover, the bath contains a surface-active compound of non-ionic character.
• the effect of the brightening agent gets lost, if the aforesaid compound contains a substituent reducible in this medium, for example a nitro-group or an ionisable substituent, for example a sulphonic acid-, a carboxylic acid-, an aminoor a substituted amino-group.
• a substituent reducible in this medium for example a nitro-group or an ionisable substituent, for example a sulphonic acid-, a carboxylic acid-, an aminoor a substituted amino-group.
• ketones or keto-aldehydes operating as brightening agents in the scope of the invention for example coupling products with aniline, so-called Schifis bases, have the same effect, since, dissolved in the tinplating bath, they are converted by hydrolysis into the ketones or keto-aldehydes themselves.
• the quantity of the brightening agent to be added for having a satisfactory brightening effect need only be small: quantities from 25 to 500 mg. per liter of bath liquid are in a satisfactory way active. There is no limit above which the effect disappears, but the addition of large quantities is, of course, not advisable for economic reasons. Moreover, a limit may be imposed by the solubility.
• Lissapol N is a non-ionic, surface-active substance, a condensate of alkylphenols and ethylene oxide.
• the brightening agents employed are:
• An aqueous acidic electro-plating bath for depositing tin, containing bivalent tin ions, as anions sulphate-, sulphonateor fluoborate-ions and, as a brightening agent, one or more sufiiciently soluble compounds of the general formula:
• Rr-fi-C-Rl 0 0 wherein R is an aliphatic, aromatic, ,alicyclic or heterocylic group or a mixed aliphatic aromatic group, substituted only with non-ionisable substituents or substituents not reducible in said bath and R is hydrogen or one of the said groups or wherein the group References Cited UNITED STATES PATENTS 1/ 1949 Du Rose et a1 204-43 1/ 1968 Korpiun et al 204--54 JOHN H. MACK, Primary Examiner.

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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)
• Chemically Coating (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=19793123

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (1)

Citations (2)

• 1965
  • 1965-05-11 NL NL6505921A patent/NL6505921A/xx unknown
• 1966
  • 1966-03-25 US US537300A patent/US3429790A/en not_active Expired - Lifetime
  • 1966-05-06 GB GB20143/66A patent/GB1084378A/en not_active Expired
  • 1966-05-09 FR FR60763A patent/FR1479037A/fr not_active Expired
  • 1966-05-09 AT AT436166A patent/AT263473B/de active
  • 1966-05-09 DE DEN28502A patent/DE1264919B/de active Pending
  • 1966-05-09 BE BE680770D patent/BE680770A/xx unknown
  • 1966-05-09 ES ES0326510A patent/ES326510A1/es not_active Expired

Patent Citations (2)

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