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
  • C25D3/56—Electroplating: Baths therefor from solutions of alloys
• • 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
  • C25D3/34—Electroplating: Baths therefor from solutions of lead
  • C25D3/36—Electroplating: Baths therefor from solutions of lead characterised by the organic bath constituents used

Definitions

• the present invention relates to a method according to claim 1 for acidic, electrolytic deposition of lead and predominantly layers containing lead on surfaces of an electrolyte, the lead salts and acids, in particular Alkanesulfonic acid, borofluorohydric acid or Contains hydrofluoric acid. Furthermore concerns the present invention for performing an electrolyte of the process and the use of surfactants in acidic lead electrolytes.
• Acid lead electrolytes are known from US Pat. No. 2,525,942 the base of the alkanesulfonate is known.
• the disadvantage of electrolytes mentioned there is that the deposited therefrom Lead an amorphous, non-dense, porous layer of lead results. Furthermore, this electrolyte can only be used in be deposited in a very narrow current density range.
• US-A-4,701,244 discloses an electrolytic bath for Tin and lead deposition in the presence of an excess of lower alkyl sulfonic acid or acid salt, the following Additives contains: additives such as benzal acetone, benzaldehydes and aromatic pyridines, surface-active Substances such as betaines, alkylene oxide, polymers, imidazolinium compounds and quaternary ammonium salts and Formaldeyd. Nowhere will the combination of Nio- and cationic surfactants in an electrolyte for deposition of lead and mostly lead-containing layers disclosed.
• the object of the present invention is a method for acidic, electrolytic deposition of lead and to provide predominantly lead-containing layers on surfaces, the advantages of which with electrolysis Lead perchlorate resembles without the extraordinary danger to have the same procedure.
• the method according to the invention can now smooth, dense and fine crystalline lead deposits can be achieved even on strongly deformed base materials.
• the polarization phenomena of the previously used Electrolytes in both the anode and cathode reactions reduced.
• the applicable cathodic current densities are higher. So can with much lower lead contents be worked in the electrolyte. Hence, too the rinse water is less contaminated with lead. Overall will thus the disposal of both the leaded electrolyte as well as the rinse water significantly simplified.
• the present invention accordingly relates to a process according to claim 1 for the acidic, electrolytic deposition of lead and predominantly lead-containing layers on surfaces by means of an electrolyte which contains lead salts and acids, in particular alkanesulfonic acid, borofluoric acid or silicic acid.
• an electrolyte which contains lead salts and acids, in particular alkanesulfonic acid, borofluoric acid or silicic acid.
• a temperature of 20 to 80 ° C., preferably 30 to 50 ° C. is used.
• a free acid content of 50 to 150 g / l is preferred.
• the lead content is preferably 10 to 200 g / l.
• a lead content of 10 to 60 g / l is particularly preferred.
• the concentration of the non-ionic and cationic surfactants should total 1 to 15 g / l.
• the concentration of cationic surfactants is preferably 0.1 to 3 g / l.
• the soluble lead salt and the optionally further metal salts are preferably fluoroborates, fluorosilicates and / or alkanesulfonates.
• a copper and / or tin salt is particularly preferred as a further soluble metal salt.
• the nonionic surfactant is preferably an alkanol, alkylphenol, alkylamino, arylphenol polyglycol ether or block polymer of ethylene oxide or propylene oxide. If the nonionic surfactant is a polyglycol ether, it preferably has 7 to 30 mol ethylene oxide / mol.
• the polyglycol ether preferably has a C 5 -C 20 alkanol or alkyl radical.
• a cationic surfactant preferably a quaternary ammonium compound, is present in addition to the nonionic surfactant.
• Another object of the present invention is the use of non-ionic and cationic surfactants in acidic Lead electrolytes for the electrolytic deposition of Lead and mostly lead-containing layers on surfaces according to claim 16.
• Electrolyte I (state of the art) 110.0 g / l Lead as lead fluoroborate 50.0 g / l free borofluoric acid 0.2 g / l Glue.
• Electrolyte II (state of the art) 20.0 g / l Lead as lead alkanesulfonate 5.0 g / l free alkanesulfonic acid 0.2 g / l Glue.
• Electrolyte III (state of the art) 15.0 g / l Lead as lead fluoroborate 50.0 g / l free borofluoric acid 3.0 g / l Nonylphenol polyglycol ether with 10 mol ethylene oxide / mol
• Electrolyte IV (according to the invention) 15.0 g / l Lead as lead fluoroborate 50.0 g / l free borofluoric acid 3.0 g / l Nonylphenol polyglycol ether with 10 mol ethylene oxide / mol 0.5 g / l Dodecyl dimethyl benzyl ammonium chloride
• Electrolyte V (according to the invention) 20.0 g / l Lead as lead fluorosilicate 50.0 g / l free silica hydrofluoric acid 5.0 g / l Coconut fatty alcohol polyglycol ether with 13 mol ethylene oxide / mol 1.0 g / l Ditallow
• the above electrolytes were in a Hull cell subjected to electrolysis with brass sheets. It was with a cell current of 1.5 amp. 10 minutes at room temperature with gentle stirring by a magnetic stirrer electrolyzed.
• electrolytes could only do dark and gray lead deposits be preserved. That was also the case with electrolyte I. Sheet burned amorphously in the high current density range. With electrolyte II only the first 2 cm covered with a dark amorphous layer. From approx. 5 cm there was no separation. The electrolyte III showed a burn in in the high current density range Dark amorphous deposition.
• the process according to the invention is advantageously suitable for providing solderable layers on surfaces by means of co-deposition of, for example, tin and / or copper (lead with proportions of 5 to 15% tin).
• an electrolyte of the following composition was used for the electrolytic coating of a brass sheet under the same conditions as in the comparative experiment: 20.0 g / l Lead as lead fluoroborate 2.0 g / l Tin as tin fluoroborate 50.0 g / l free borofluoric acid 2.0 g / l ⁇ -naphthol polyglycol ether with 12 mol ethylene oxide / mol 0.5 g / l Dodecyl dimethyl benzyl ammonium chloride
• the fine crystalline and bright precipitate turned out to be as excellent solderable.
• An analysis of the detached and analyzed precipitation showed a content of 88% by weight of lead and 12% by weight of tin.
• Lead-containing run-in layers on slide bearings (lead with 10% tin and 3% copper) are also of particular interest.
• an electrolyte of the following composition at a current density of approx. 10 amp./dm 2 was used to coat bearing shells with an approx. 30 ⁇ m thick running-in layer.
• the electrolysis produced a fine crystalline and bright precipitate. Analysis of the precipitation showed: Lead 85%, Tin 11%, Copper 4%

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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)
• Electrolytic Production Of Metals (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Electroplating Methods And Accessories (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1989
  • 1989-10-19 DE DE3934866A patent/DE3934866A1/de active Granted
• 1990
  • 1990-10-05 JP JP2513610A patent/JPH05502475A/ja active Pending
  • 1990-10-05 AT AT90914695T patent/ATE162856T1/de not_active IP Right Cessation
  • 1990-10-05 US US07/848,952 patent/US5443714A/en not_active Expired - Fee Related
  • 1990-10-05 KR KR1019920700882A patent/KR0185204B1/ko not_active IP Right Cessation
  • 1990-10-05 WO PCT/EP1990/001670 patent/WO1991005890A1/de active IP Right Grant
  • 1990-10-05 ES ES90914695T patent/ES2113350T3/es not_active Expired - Lifetime
  • 1990-10-05 DE DE59010802T patent/DE59010802D1/de not_active Expired - Fee Related
  • 1990-10-05 EP EP90914695A patent/EP0607119B1/de not_active Expired - Lifetime

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