EP0330722A1 - Procédé électrochimique pour la production de revêtements en chrome et métaux similaires, au moyen de courant pulsé à polarité inversant périodiquement et appareillage à cet effet - Google Patents

Procédé électrochimique pour la production de revêtements en chrome et métaux similaires, au moyen de courant pulsé à polarité inversant périodiquement et appareillage à cet effet Download PDF

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Publication number
EP0330722A1
EP0330722A1 EP88105380A EP88105380A EP0330722A1 EP 0330722 A1 EP0330722 A1 EP 0330722A1 EP 88105380 A EP88105380 A EP 88105380A EP 88105380 A EP88105380 A EP 88105380A EP 0330722 A1 EP0330722 A1 EP 0330722A1
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EP
European Patent Office
Prior art keywords
polarity
layer
rectifier
waves
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.)
Granted
Application number
EP88105380A
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German (de)
English (en)
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EP0330722B1 (fr
Inventor
Luigi Blesio
Mario Leoni
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ELCA Srl
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ELCA Srl
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Publication of EP0330722A1 publication Critical patent/EP0330722A1/fr
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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
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/10—Electroplating with more than one layer of the same or of different metals
    • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
    • C25D5/14—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium two or more layers being of nickel or chromium, e.g. duplex or triplex layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/18—Electroplating using modulated, pulsed or reversing current

Definitions

  • the present invention relates to an electrochemical process for producing platings (deposits) of such metals as chromium, nickel, and the like, by using double-level pulsating electrical current, with said two levels being of reverse polarity relatively to each other, and adjustable, with said pulsating electrical current alternating with rectified current.
  • An object of the present invention is also a suitable equipment for carrying out said process, and consisting of a generator of electrical waves pulsating between two levels relatively to a zero line, i.e., of waves of periodically reversing polarity, and adjustable according to as required.
  • a type of rectifier equipment showed to be particularly efficacious, which is equipped with an electronic device for the periodic reversal of polarity, provided with means for adjusting the parameters which define the wave form.
  • the purpose of the present invention is to provide a plating process by electrodeposition of such metals as chromium, nickel and the like, which is capable of overcoming the drawbacks and disadvantages shown by the electrodeposition technique known from the prior art, including that technique which only uses pulsating currents with periodical reversing polarity.
  • Another purpose of the present invention is to provide a process for producing plating layers of chromium, and the like, which can be easily practiced, is adjustable relatively to the types and materials of the support to be plated, and to the characteristics of hardness, elasticity and corrosion resistance desired for the layers to be obtained, by using a current rectifier generating waves pulsating between a plurality of levels, of reverse polarity relatively to one another.
  • a plating process by electrodeposition of such metals as chromium, nickel, and the like, which consists, according to the present invention, in depositing on the support to be plated at least a first layer of such a plating metal as chromium, nickel and the like, by using a current rectifier equipped with an electronic device for periodically reversing and adjusting the polarity, in such a way as to obtain said first layer with no cracks, then in depositing on said first layer at least a second layer by using the only positive polarity which is obtainable from said rectifier, in such a way as to endow said second layer with the required values of hardness and elasticity.
  • the passage from the periodically reversing polarity for obtaining said first, crack-free layer to the only positive polarity for obtaining said second layer having the required values of hardness and elasticity can be advantageously carried out both in a sudden, or instantaneous, way, and in a progressive way, by adjusting said current rectifier with periodic reversal of polarity, so as to create a progressive increase in the time interval (duration) between two successive negative pulses, and obtain a gradual passage from the lower, crack-free layer, to the upper layer.
  • said plating process can be carried out by creating a plurality of alternating layers, i.e., layers obtained by means of the use of current with reversing polarity, alternating with current with only positive polarity.
  • an electronic equipment which generates waves pulsating between two or more levels of reversed polarity relatively to one another, and adjustable, which equipment is substantially constituted by a main rectifier generating a unidirectional positive current of the controlled-diode type, and by a similar rectifier connected in antiparallel to the main rectifier, so as to obtain an output which is constituted by a current wave form showing periodic and extremely short polarity reversals, i.e., an at least double-level wave form, with at least one positive level alternating with a negative level, as shown in Figure 1, in which by the reference numeral 1 the positive square waves are indicated, which alternate with negative square waves 2, relatively to a zero level direct current; the values of amplitude B and of duration C of the negative waves and the time interval - or pause time - D between said negative waves can be independently adjusted by means of a suitable device or circuit controlling the negative or reverse polarity associated with said rectifiers.
  • the equipment furthermore comprises a static interblock circuit capable of excluding, alternatively and for preset time periods, one of the rectifiers, while the other rectifier is operating. More particularly, said means for adjusting the electrical quantities of the output waves are constituted by individual potentiometers, and said static interblock circuit interposed between said two rectifiers is of a traditional type.
  • said deposit is produced by depositing on the metal support 3 ( Figure 2) a first chromium layer, indicated by the reference numeral 51, by using current with periodically reversing polarity and adjusting, relatively to the characteristics of the support 3 and to the desired thickness of the layer 51, the wave form parameters, i.e., the pulse durations and amplitudes, in such a way as to obtain a deposit which is completely free from cracks; then disabling the rectifier generating the waves with periodic polarity reversal, and letting only operate the rectifier which generates only positive waves, on the first layer 51 a second layer 52 is deposited.
  • the wave form parameters i.e., the pulse durations and amplitudes
  • the present Applicant observed that by operating according to this procedure, the values of hardness and elasticity of the plating result comparable to those shown by deposits applied according to the traditionale route, whilst the corrosion resistance is considerably increased. Still according to the present invention, it was also observed that by applying a progressive increase of the time interval "D" between two successive negative pulses 2, a gradual passage can be attained from the underlying layer 51 to the external layer 52, i.e., a gradual passage from the crack-free layer, to the external layer affected by cracks.
  • the deposit is given a high corrosion resistance (by the layer 51) and high values of hardness and elasticity (by the layer 52).
  • the plating process can be accomplished by alternating with one another a plurality or layers obtained with current with periodic polarity reversal polarity, alternating with only positive current.
  • values of hardness and corrosion resistance can be obtained, which are higher than those which can be obtained with two layers only.
  • by accomplishing the double-layer, or the multi-­alternating-layer deposit such a sufficiently shiny appearance of the outermost layer can be obtained, as to render useless the polishing operations.
  • FIG. 3 a diagram is shown, which represents an equipment capable of generating double-level pulsating waves characterized by periodic and extremely short reversals of polarity according to the present invention; said equipment is constituted by a main rectifier 3, preferably with an hexa-phase circuit structure and of the controlled-diode type, such as to output a unidirectional pulsating current; with said rectifier, a similar rectifier 5 is connected in antiparallel by means of the leads 4-4a, which generates a unidirectional pulsating current, with reversed polarity, i.e., capable of emitting, during adjustable times, and for adjustable durations, waves with a reverse polarity relatively to the waves generated by the main rectifier.
  • a main rectifier 3 preferably with an hexa-phase circuit structure and of the controlled-diode type, such as to output a unidirectional pulsating current
  • a similar rectifier 5 is connected in antiparallel by means of the leads 4-4a, which
  • a control circuit is connected, which is generally indicated by the reference numeral 6, for the independent adjustment of the times B and C and of the amplitude A of the reverse-polarity waves 2.
  • Such adjustment means comprise three potentiometers A1, B1 and C1, and precisely: the potentiometer A1, for the adjustment of the amplitude - or intensity - A of the reverse-­polarity waves 2; the potentiometer B1, for the adjustment of the pause times B between two successive negative waves; and the third potentiometer C1, for adjusting the duration times C of said negative waves.
  • the reversals of polarity are adjusted in such a way as to take place periodically and for extremely short times, of the order of milliseconds, so as to make it possible the main pulsating current to be interrupted and followed by negative pulsating current for very short times, and with adjustable intensities, according to the selected treatment type.
  • a circuit of static interblock (not shown, in that it is of a type known and suitable for the intended purpose) with the main rectifier is provided, which is capable of making operate, for the preset times, the only reverse-polarity-wave rectifier.
  • the process can be used, by suitably adjusting the parameters of the wave form of the current with periodical polarity reversal, in order to obtain electrodepositions of any metals, with layers having desired thicknesses, and with a number of alternating layers which can be adjusted to meet the various requirements.

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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 Methods And Accessories (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Secondary Cells (AREA)
  • Cell Electrode Carriers And Collectors (AREA)
EP88105380A 1988-03-04 1988-04-05 Procédé électrochimique pour la production de revêtements en chrome et métaux similaires, au moyen de courant pulsé à polarité inversant périodiquement et appareillage à cet effet Expired - Lifetime EP0330722B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88105380T ATE72587T1 (de) 1988-03-04 1988-04-05 Elektrochemischer prozess zur herstellung von plattierungen aus chrom oder aehnlichen metallen mittels pulsierendem strom mit periodisch umkehrender polaritaet und dazugehoerende einrichtungen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8819644A IT1215985B (it) 1988-03-04 1988-03-04 Procedimento elettrochimico per la realizzazione di rivestimenti di cromo e metalli simili mediante corrente pulsante ad inversione periodica della polarita'
IT1964488 1988-03-04

Publications (2)

Publication Number Publication Date
EP0330722A1 true EP0330722A1 (fr) 1989-09-06
EP0330722B1 EP0330722B1 (fr) 1992-02-12

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Family Applications (1)

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EP88105380A Expired - Lifetime EP0330722B1 (fr) 1988-03-04 1988-04-05 Procédé électrochimique pour la production de revêtements en chrome et métaux similaires, au moyen de courant pulsé à polarité inversant périodiquement et appareillage à cet effet

Country Status (5)

Country Link
EP (1) EP0330722B1 (fr)
AT (1) ATE72587T1 (fr)
BR (1) BR8901046A (fr)
DE (1) DE3868400D1 (fr)
IT (1) IT1215985B (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236763A (en) * 1989-10-11 1991-04-17 Lpw Chemie Gmbh A process for the direct or indirect electro-deposition of a highly corrosion resisting crack-tree technical hard chromium plating layer
EP0596589A1 (fr) * 1992-10-15 1994-05-11 Telectronics N.V. Méthode pour réduire la polarisation des conducteurs de stimulation bioélectriques en utilisant l'amélioration de surface, et produit en résultant
DE19745811A1 (de) * 1997-10-16 1999-04-22 Federal Mogul Burscheid Gmbh Galvanische Hartchromschicht
EP0972861A3 (fr) * 1998-06-26 2000-05-24 Nippon Piston Ring Co., Ltd. Couches de placage laminées avec une resistance à l'usure et à la fatigue superieure
CN102330127A (zh) * 2011-10-10 2012-01-25 长沙中联重工科技发展股份有限公司 输送缸及其制备方法以及包括其的泵送设备
WO2013053097A1 (fr) * 2011-10-10 2013-04-18 长沙中联重工科技发展股份有限公司 Cylindre de transport, son procédé de fabrication et équipement de pompage le contenant
US10449749B1 (en) 2018-05-03 2019-10-22 Triumph Aerostructures, Llc. Thermoplastic aerostructure with localized ply isolation and method for forming aerostructure
US10457405B1 (en) 2018-04-24 2019-10-29 Triumph Aerostructures, Llc. Composite aerostructure with integrated heating element
US10941502B2 (en) 2015-10-27 2021-03-09 Metal Protection Lenoli Inc. Electrolytic process and apparatus for the surface treatment of non-ferrous metals

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3975254A (en) * 1974-08-13 1976-08-17 Westinghouse Electric Corporation Forward-reverse pulse cycling anodizing and electroplating process power supply
DE2555834C2 (de) * 1974-12-11 1983-10-06 Laing Phys-Tech Entw Inst Verfahren zur elektrolytischen Abscheidung von Chrom
US4496436A (en) * 1976-09-01 1985-01-29 Inoue-Japax Research Incorporated Pulse electrodepositing method
US4666567A (en) * 1981-07-31 1987-05-19 The Boeing Company Automated alternating polarity pulse electrolytic processing of electrically conductive substances

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3975254A (en) * 1974-08-13 1976-08-17 Westinghouse Electric Corporation Forward-reverse pulse cycling anodizing and electroplating process power supply
DE2555834C2 (de) * 1974-12-11 1983-10-06 Laing Phys-Tech Entw Inst Verfahren zur elektrolytischen Abscheidung von Chrom
US4496436A (en) * 1976-09-01 1985-01-29 Inoue-Japax Research Incorporated Pulse electrodepositing method
US4666567A (en) * 1981-07-31 1987-05-19 The Boeing Company Automated alternating polarity pulse electrolytic processing of electrically conductive substances

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236763A (en) * 1989-10-11 1991-04-17 Lpw Chemie Gmbh A process for the direct or indirect electro-deposition of a highly corrosion resisting crack-tree technical hard chromium plating layer
GB2236763B (en) * 1989-10-11 1993-11-17 Lpw Chemie Gmbh A process for the direct or indirect deposition of a highly corrosion resisting technical hard chromium plating layer
EP0596589A1 (fr) * 1992-10-15 1994-05-11 Telectronics N.V. Méthode pour réduire la polarisation des conducteurs de stimulation bioélectriques en utilisant l'amélioration de surface, et produit en résultant
DE19745811C2 (de) * 1997-10-16 2002-06-13 Federal Mogul Burscheid Gmbh Galvanische Hartchromschicht, Verwendung und Verfahren zu deren Herstellung
DE19745811A1 (de) * 1997-10-16 1999-04-22 Federal Mogul Burscheid Gmbh Galvanische Hartchromschicht
EP0972861A3 (fr) * 1998-06-26 2000-05-24 Nippon Piston Ring Co., Ltd. Couches de placage laminées avec une resistance à l'usure et à la fatigue superieure
US6296951B1 (en) 1998-06-26 2001-10-02 Nippon Piston Ring Co., Ltd. Laminated chromium plating layers having superior wear resistance and fatigue strength
CN102330127A (zh) * 2011-10-10 2012-01-25 长沙中联重工科技发展股份有限公司 输送缸及其制备方法以及包括其的泵送设备
CN102330127B (zh) * 2011-10-10 2012-12-05 中联重科股份有限公司 输送缸及其制备方法以及包括其的泵送设备
WO2013053097A1 (fr) * 2011-10-10 2013-04-18 长沙中联重工科技发展股份有限公司 Cylindre de transport, son procédé de fabrication et équipement de pompage le contenant
US10941502B2 (en) 2015-10-27 2021-03-09 Metal Protection Lenoli Inc. Electrolytic process and apparatus for the surface treatment of non-ferrous metals
US10457405B1 (en) 2018-04-24 2019-10-29 Triumph Aerostructures, Llc. Composite aerostructure with integrated heating element
US11577845B2 (en) 2018-04-24 2023-02-14 Qarbon Aerospace (Foundation), Llc Composite aerostructure with integrated heating element
US10449749B1 (en) 2018-05-03 2019-10-22 Triumph Aerostructures, Llc. Thermoplastic aerostructure with localized ply isolation and method for forming aerostructure
US11440288B2 (en) 2018-05-03 2022-09-13 Qarbon Aerospace (Foundation), Llc Thermoplastic aerostructure with localized ply isolation and method for forming aerostructure

Also Published As

Publication number Publication date
IT8819644A0 (it) 1988-03-04
IT1215985B (it) 1990-02-22
EP0330722B1 (fr) 1992-02-12
BR8901046A (pt) 1989-10-24
ATE72587T1 (de) 1992-02-15
DE3868400D1 (de) 1992-03-26

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