EP0330722A1
Expired / Lapsed
EP
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Electrochemical process for producing platings of chromium and similar metals, by means of pulsating current with periodic reversing polarity, and relevant equipment
Assignee: ELCA Srl
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Filing: 1988-04-05
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Granted: —
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Expires: 2008-04-05
Abstract
Abstract Electrochemical process for producing platings of such metals as chromium, nickel and the like, consisting in depositing on the support to be plated at least a first layer of plating metal such as chromium, nickel and the like, by using a current rectifier equipped with an electronic device for the periodic and adjustable reversal of polarity, in such a way as to obtain said first layers with no cracks, then in subsequently depositing on said first layer at least a second layer by using the only positive polarity obtainable from said rectifier, so as to endow said second layer with the required values of hardness and elasticity. Equipment for carrying out such a process, which consists in a generator of double-level pulsating electrical waves, comprising means for independently adjusting the time intervals between two consecutive negative pulses and the duration time and amplitude of the negative waves.
Inventors
- 👤 Luigi Blesio
- 👤 Mario Leoni
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:20
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/10; C25D5/12; C25D5/14; C25D5/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
Electrochemical process for depositing platings of chromium, nickel, and other similar metals, characterized in that it consists 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.
Claim 2
Dependent Claim
113 words
Electrochemical process for depositing platings of chromium, nickel, and other similar metals, characterized in that it consists 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.
Claim 3
Dependent Claim
47 words
Process according to claim 1, characterized in that the passage from the periodically reversing polarity for obtaining said first layer without cracks to the only positive polarity for obtaining said second layer having the required values of hardness and elasticity is carried out in an instantaneous way.
Claim 4
Dependent Claim
79 words
Process according to claim 1, characterized in that the passage from the periodically reversing polarity for obtaining said first layer without cracks to the only positive polarity for obtaining said second layer is carried out in a progressive way, by adjusting said current rectifier in such a way as to accomplish a progressive increase in the time interval between two successive negative pulses, in order to obtain a gradual passage from the lower, crack-free layer to the top layer.
Claim 5
Dependent Claim
32 words
Process according to claim 1, characterized in that the plating is carried out by depositing a plurality of alternating layers obtained by using reversing-polarity current alternating to current with only positive polarity.
Claim 6
Dependent Claim
159 words
Equipment generating electrical pulsating waves for facilities for the electrodeposition of plating metals, such as chromium, nickel, and the like, characterized in that it is constituted by a main current rectifier of the controlled-diode type, and by a similar rectifier connected in antiparallel with the main rectifier, so as to obtain an output 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 relatively to the zero level direct current, with said rectifiers a control circuit for the negative or reverse polarity comprising means for independently adjusting the pause times, and the duration times of the negative waves, and the amplitude of said negative waves, as well as a circuit of static interblock with said main rectifier, capable of excluding, alternatively and for preset times, the main rectifier, while the other rectifier is emitting reverse-polarity waves, being associated.
Claim 7
Dependent Claim
159 words
Equipment generating electrical pulsating waves for facilities for the electrodeposition of plating metals, such as chromium, nickel, and the like, characterized in that it is constituted by a main current rectifier of the controlled-diode type, and by a similar rectifier connected in antiparallel with the main rectifier, so as to obtain an output 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 relatively to the zero level direct current, with said rectifiers a control circuit for the negative or reverse polarity comprising means for independently adjusting the pause times, and the duration times of the negative waves, and the amplitude of said negative waves, as well as a circuit of static interblock with said main rectifier, capable of excluding, alternatively and for preset times, the main rectifier, while the other rectifier is emitting reverse-polarity waves, being associated.
Claim 8
Dependent Claim
61 words
Equipment according to claim 5, characterized in that said means for adjusting the electical quantities of the output waves are constituted by independent potentiometers, one of which is for adjusting the amplitude of the reverse-polarity waves, one is for adjusting the pause times between two successive negative waves, and another one is for adjusting the duration times of said negative waves.
Claim 9
Dependent Claim
40 words
Equipment according to clam 5, characterized in that said periodic reversals of polarity are adjusted by means of a circuit of interblock with the main rectifier, capable of causing said polarity reversals for duration times of the order of milliseconds.
Claim 10
Dependent Claim
40 words
Equipment according to clam 5, characterized in that said periodic reversals of polarity are adjusted by means of a circuit of interblock with the main rectifier, capable of causing said polarity reversals for duration times of the order of milliseconds.
References Cited (Backward Citations)
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