EP0357326A2 - Korrosionsschutz von Anoden aus Blei oder Bleilegierung in einem Chrom-Elektroplattierungsbad - Google Patents

Korrosionsschutz von Anoden aus Blei oder Bleilegierung in einem Chrom-Elektroplattierungsbad Download PDF

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Publication number
EP0357326A2
EP0357326A2 EP89308528A EP89308528A EP0357326A2 EP 0357326 A2 EP0357326 A2 EP 0357326A2 EP 89308528 A EP89308528 A EP 89308528A EP 89308528 A EP89308528 A EP 89308528A EP 0357326 A2 EP0357326 A2 EP 0357326A2
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EP
European Patent Office
Prior art keywords
anode
lead
potential
electroplating
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89308528A
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English (en)
French (fr)
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EP0357326A3 (de
Inventor
Allen R. Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
M&T Chemicals Inc
Original Assignee
M&T Chemicals Inc
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Filing date
Publication date
Application filed by M&T Chemicals Inc filed Critical M&T Chemicals Inc
Publication of EP0357326A2 publication Critical patent/EP0357326A2/de
Publication of EP0357326A3 publication Critical patent/EP0357326A3/de
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
    • 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
    • C25D3/04—Electroplating: Baths therefor from solutions of chromium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/005—Anodic protection

Definitions

  • This invention relates to the electrodeposition of chromium, using lead or lead-alloy anodes, and, more partic­ularly, to a chromium-plating bath apparatus and process, in which the weight loss of such lead anodes is substantially reduced.
  • Chromium-plating baths using chromic-acid solutions as the source of chromium almost invariably employ lead or lead-­alloy anodes.
  • lead and lead-alloy anodes corrode to a soluble species (leading to anode weight loss) in chromic-acid solutions.
  • This anode dis­solution proceeds at a substantial rate, the rate being pro­portional to the acidity of the solution.
  • the addition of one to two grams per liter (g/l) of Co2+ ions also may reduce anode corrosion.
  • HEEF-25 baths comprise chromic acid, sulfate and an alkyl sulfonic acid, which, for functional chromium deposits, is preferably a non-­substituted alkyl sulfonic acid, or salt thereof, wherein the ratio of sulfur to carbon is ⁇ 1/3.
  • Typical alkyl sulfonic acids are methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, methane disulfonic acid and 1,2-ethane disulfonic acid.
  • the present invention seeks to reduce the problem of anode corrosion.
  • the invention provides a chromium-plating system which significantly reduces the conversion of a lead or lead-alloy anode used in that system to a soluble species, com­prising an anode-protection circuit for applying a protective potential on said anode, the potential being less than the potential required for normal electrodeposition of chromium on said anode.
  • the electroplating bath of this invention may be the conventional mixed-catalyst or alkyl sulfonic-acid-containing (HEEF-25) chromium-electroplating type.
  • an auxiliary cathode is provided near the anode, and the desired voltage is imposed on the anode.
  • the surface of the lead or lead-alloy anode used therein is oxidized to a film of lead dioxide on the anode, which stabilizes the anode during the process.
  • this protective lead dioxide film can be reduced to a lead (II) oxide species by the lead anode, or by trivalent chromium in solution, producing chromate ions.
  • the lead (II) oxide may react with the chromate ions to form insoluble lead chromate. If the lead oxide and lead chromate materials are as adherent on the lead anode as the lead dioxide film, very little corrosion of the anode will occur. However, if these species flake off the anode and fall into the bath, fresh lead-anode surface is exposed, and further corrosion can occur.
  • the formation of lead (II) species is slowed by anodic protection during periods of non-plating, thereby slowing anodic solubilizing corrosion and anode-weight loss.
  • Anodic protection is preferably achieved in the electro­plating system of the invention by providing an auxiliary, or dummy, cathode positioned near the anode, and imposing a pre­determined low voltage between that cathode and the anode at a low current. This voltage is less than the operational potential between the anode and the substrate cathode, which would other­wise result in electrodeposition of chromium. In this manner, an anodic or oxidizing potential is maintained around the beneficial lead (IV) dioxide film on the anode, to prevent its reduction to a lead (II) species.
  • anodic protection is obtained by applying a voltage of less than the plating voltage to the anode. For instance, potentials of from about 1.8 to about 2.2 volts (v.) at currents of from about 0.01 to about 0.3% of normal chromium electroplating currents were found to be useful in reducing solubilizing corrosion of lead and lead-alloy anodes. Further, the protective current can be applied both while the bath is in operation and while the plating current is off, such as overnight.
  • the auxiliary circuit of the embodiment includes an auxiliary cathode 2, which can be a chromium-plated rod, positioned near the anode 1 and connected in series therewith through an auxiliary power supply 5.
  • a rectifier or diode 6 is included in the auxiliary circuit to permit the auxiliary circuit to be left on even during electroplating.
  • a dummy cathode and plating rectifier, in combination, can also be used.
  • an anodic protection voltage of less than the normal plating potential, about 2.8 v. is applied between the auxiliary cathode and the anode.
  • a potential of at least 2 v. is applied, at less than 0.02% of the plating cur­rent.
  • a voltage of 2.0 v. for 1500 amp-hr provides a 10-20% improvement in Pb- 7% Sn anode corrosion, as determined by weight loss, while 2.15 v. at less than 0.1% of the plating current results in a 35-55% reduction in the anode corrosion (mass loss) in a HEEF-25 chromium plating bath, as compared to 1500 amp-hr of plating without the auxiliary protection circuit.
  • the anode-protection circuit of Figure 1 was used and the auxiliary power supply was kept on even when plating was not occurring.
  • the diode was a three-ampere (amp) 50 peak-inverse-­voltage epoxy type with a voltage drop of about 0.5 v.
  • the power supply was about 0.5 v higher than the voltage at the voltmeter indicated as V in the drawing.
  • a low-ripple rectifier was used for plating (Hewlett-Packard 6268B, 40 v, 30 amp) and for the auxiliary circuit (Hewlett-Packard, 6200B, 20 v, 1.5 amp).
  • the auxiliary voltage was controlled at 2.0 and 2.15 v. in two separate experiments. Each test lasted for 1500 amp-hr (about one month), and the anodes were weighed four times during the experiments after a plating cycle. A thin brown film wad rubbed off the anodes prior to weighing. During the day, plating was cycled on and off every 30 minutes. Plating, heating and stirring were turned off at night. Chromic acid was replenished during the tests. Seven liters of HEEF-25 plating solution (containing 250 grams/liter [g/l.] of chromic acid and 3.5 g/l. of methyl sulfonic acid and 2.5 g/l.
  • Table 1 demonstrates that with anodic protection of 2.0 v. less than 0.02% of the plating current, the test anode cor­roded 10 to 20% less than the control anode.
  • Table 2 shows that at 2.15 v. less than 0.1% of the plating current, the test anode corroded 35 to 55% less than the control anode. It is seen, therefore, that anodes with protection showed a mass loss of up to about half that found with anodes used without protection. In both determinations, the control anodes corroded at the same rate within 1%.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
EP19890308528 1988-08-26 1989-08-23 Korrosionsschutz von Anoden aus Blei oder Bleilegierung in einem Chrom-Elektroplattierungsbad Withdrawn EP0357326A3 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US23760788A 1988-08-26 1988-08-26
US237607 1988-08-26
US35573789A 1989-05-22 1989-05-22
US355737 1989-05-22

Publications (2)

Publication Number Publication Date
EP0357326A2 true EP0357326A2 (de) 1990-03-07
EP0357326A3 EP0357326A3 (de) 1990-10-24

Family

ID=26930845

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890308528 Withdrawn EP0357326A3 (de) 1988-08-26 1989-08-23 Korrosionsschutz von Anoden aus Blei oder Bleilegierung in einem Chrom-Elektroplattierungsbad

Country Status (4)

Country Link
EP (1) EP0357326A3 (de)
JP (1) JPH02310397A (de)
KR (1) KR900003422A (de)
CN (1) CN1040633A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2281642A1 (de) * 2008-03-28 2011-02-09 Sumitomo Metal Industries, Ltd. Verfahren zum plattieren einer dornstange mit cr, dornstange und verfahren zur herstellung eines nahtlosen rohrs unter verwendung des verfahrens und der dornstange

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10215463C1 (de) * 2002-03-28 2003-07-24 Atotech Deutschland Gmbh Durchlaufanlage und Verfahren zum elektrolytischen Metallisieren von Werkstück
CN103088373A (zh) * 2011-10-31 2013-05-08 肖云捷 一种电铸过程中防止烧焦的有效方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1148070A (en) * 1965-04-16 1969-04-10 M & T Chemicals Inc Improvements in or relating to electrodeposition of chromium
US4062741A (en) * 1975-02-24 1977-12-13 Teikoku Piston Ring Co., Ltd. Method for maintaining an electrode and an article plated or to be plated immersed in an electrolytic chromium-plating bath in a normal condition

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1148070A (en) * 1965-04-16 1969-04-10 M & T Chemicals Inc Improvements in or relating to electrodeposition of chromium
US4062741A (en) * 1975-02-24 1977-12-13 Teikoku Piston Ring Co., Ltd. Method for maintaining an electrode and an article plated or to be plated immersed in an electrolytic chromium-plating bath in a normal condition

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2281642A1 (de) * 2008-03-28 2011-02-09 Sumitomo Metal Industries, Ltd. Verfahren zum plattieren einer dornstange mit cr, dornstange und verfahren zur herstellung eines nahtlosen rohrs unter verwendung des verfahrens und der dornstange
EP2281642A4 (de) * 2008-03-28 2013-10-02 Nippon Steel & Sumitomo Metal Corp Verfahren zum plattieren einer dornstange mit cr, dornstange und verfahren zur herstellung eines nahtlosen rohrs unter verwendung des verfahrens und der dornstange

Also Published As

Publication number Publication date
EP0357326A3 (de) 1990-10-24
KR900003422A (ko) 1990-03-26
CN1040633A (zh) 1990-03-21
JPH02310397A (ja) 1990-12-26

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