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

• R and R being hydrogen, alkyl or phenyl or 0R wherein R is alkyl where at least one hydrogen has been replaced by amino, alkylamino or hydroxyl groups or a secondary brightener of the formula n being 0-5 and possibly one or more hydrogen atoms in the CH group being replaced by hydroxyl groups.
• these secondary brighteners are glyoxal, vinylacetate and N-vinyl carbazole.
• the invention relates to an acid tin-plating bath containing sulphate, sulphonate or fluoborate anions and brighteners by means of which bright tin deposits can be obtained.
• Acid tin-plating baths which contain as brightener a condensation product of an aliphatic aldehyde and an organic compound having a basic nitrogen-containing group, for example a reaction product of acetaldehyde and o-toluidine. These brighteners become resinous very soon, however, so that the bath has only a short stability.
• acid tin-plating baths which contain as brightener an aromatic or heterocyclic aldehyde. These baths have the disadvantage, however, that they produce bright deposits only in a very limited current density range, only between about 5 and 20 A/sq. dm. This means that strongly profiled workpieces having sharp edges and small perforations, the electrolytic coating of which involves current density variations of a factor of even as low as 100, cannot be coated with a thin layer of uniform thickness and brightness. The current density variations are considerably larger if the electrolytic coating process is carried out in a drum.
• CHO, -COOH, -CH OH, --R or OR is a corresponding nonsaturated ketone.
• These baths moreover contain formalin, imidazolin or derivatives and mixtures thereof.
• a number of organic compounds have been found which, when added instead of formalin together with a brightener to an electrolyte tin-plating bath, have the advantage that they have a larger brightening effect on the tin obtained and that they do not have disagreeable odors.
• the usable com pounds can be found in a few chemical classes which are chemically not at all related to each other. However, the applicant has found a common electrochemical criterion which the said compounds must satisfy.
• a non-ionic surface-active substance to a solution of sulfuric acid, an aryl sulphonate or a fluo borate, the overvoltage for the separation of hydrogen at a cathode of tin is raised.
• the cell containing a platinum anode and a tin cathode; the EMF is measured between the tin cathode and the platinum anode or an auxiliary calomel electrode provided in the cell, a small quantity of the substance to be tested being added to the electrolyte liquid. If the EMF decreases after addition of X the substance, the latter suits the purpose of the invention.
• R reprsents a hydrogen atom, an alkyl group or a phenyl group and R OH
• n a value 0, 1, 2, 3, 4 or 5, while in the CH groups one or more hydrogen atoms are allowed to be replaced by OH groups.
• each of the symbols R R and R represents a hydrogen atom, an aromatic, heterocyclic or aliphatic group or a similar group which may be entirely or partly hydrated and which may have substituents which cannot be ionized or cannot be reduced in this medium
• R represents hydrogen, an alkyl group or an esterified carboxyl group, or where the combination represents a ring system, on the understanding that the group C:C-- has a purely non-saturated character.
• a further improvement is obtained by the use of the last-mentioned baths, i.e. a larger brightness and an even larger current density range if instead of formalin such a compound which is capable of reducing the overvoltage for the evolution of hydrogen at a tin cathode, is added to the tin-plating bath.
• Lissapol N is a non-ionic wetting agent which consists of a condensation product of polyoxyethylene and alkylphenol.
• tin ion anions selected from the group consisting of sulfate, organic sulfonate and fluoborate ions, at non-ionic surface active agent and an olefinically unsaturated organic carbonyl primary brightener and as a secondary brightener a polymerizable organic compound capable of reducing the overvoltage for the evolution of hydrogen at a tin cathode
• said polymerizable organic compound is selected from the group consisting of a compound of the formula wherein R is a member of the group consisting of hydrogen, alkyl and phenyl, R is a member selected from the group consisting of 011 and N R3 and R4 being selected from the group consisting of phenyl, hydrogen, alkyl and 0R wherein R is alkyl wherein at least one hydrogen atom has been replaced by a member selected from the group consisting of amino
• a carbonyl compound selected from the group consisting of aromatic and heterocyclic ring containing aldehydes wherein the carbonyl group is directly attached to one of said rings and a, B olefinically unsaturated carbonyl compounds; said carbonyl compounds being free of ionizable and reducible substituents, nitrogen containing substituents and compounds hydrolyzable in said bath to said carbonyl com- References Cited pound.

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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)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19797659

Family Applications (1)

Country Status (7)

Cited By (8)

Citations (2)

• 1966
  • 1966-09-14 NL NL666612936A patent/NL151449B/nl not_active IP Right Cessation
• 1967
  • 1967-09-11 CH CH1263867A patent/CH519581A/de not_active IP Right Cessation
  • 1967-09-11 AT AT828767A patent/AT278462B/de not_active IP Right Cessation
  • 1967-09-11 US US666983A patent/US3483100A/en not_active Expired - Lifetime
  • 1967-09-13 FR FR120832A patent/FR1536736A/fr not_active Expired
  • 1967-09-13 BE BE703841D patent/BE703841A/xx not_active IP Right Cessation
  • 1967-09-14 GB GB42001/67A patent/GB1199634A/en not_active Expired

Patent Citations (2)

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