WO2021023783A1

WO2021023783A1 - Method and system for electrolytically coating an electrically conductive strip and/or woven material by means of pulse technology

Info

Publication number: WO2021023783A1
Application number: PCT/EP2020/072032
Authority: WO
Inventors: Henry GÖRTZ; Thomas Daube; Frank PLATE; Walter Timmerbeul
Original assignee: Sms Group Gmbh
Priority date: 2019-08-05
Filing date: 2020-08-05
Publication date: 2021-02-11
Also published as: EP4010516A1; WO2021023778A1; CN114174560A; EP4010515A1; CN114207190A; WO2021023789A1; EP4010517A1; US20220275530A1; CN114174559A; EP4010518A1; WO2021023779A1; US20240229276A1; CN114207191A

Abstract

The present invention relates to a galvanic method and to a system for electrolytically coating an electrically conductive strip and/or an electrically conductive woven material that is in the form of a strip, preferably a metallic strip, such as a steel strip, a plastic strip, a glass fibre woven material strip, a carbon braided woven material strip and/or a composite material thereof, with a coating based on a metal and/or a semi-metal selected from the group 6 to 15 and/or a mixture thereof, by means of pulse technology.

Description

Process and system for the electrolytic coating of an electrically conductive strip and / or fabric using pulse technology

The present invention relates to a galvanic process and a system for the electrolytic coating of an electrically conductive strip and / or an electrically conductive strip-shaped fabric, preferably a metallic strip, such as a steel strip, a plastic strip, a glass fiber fabric strip, a carbon mesh fabric strip and / or a composite material thereof with a coating based on a metal and / or a semimetal selected from group 6 to 15 and / or a mixture thereof.

Electrolytically refined strips, such as steel strips, are now used as semi-finished products in many branches of industry, such as the automotive industry, aerospace technology, mechanical engineering, the packaging industry, and household and electrical appliance manufacture. The production of such strips is traditionally carried out in continuously operating strip treatment systems with a constant-speed passage of the strip through one or more electrolysis cells connected in series.

The coatings deposited electrolytically on one or both sides of the strip can perform various tasks and give the respective strip new product properties. These are, for example, protection against corrosion or oxidation, wear protection, the production of decorative product properties, and / or the production of magnetic and / or electrical surface properties. For example, the zinc coating gives an electrolytically galvanized steel strip an active protection against corrosion and offers a good primer for painting and / or laminating with plastic films. On

Chromium coating also gives a steel strip or a plastic strip increased protection against corrosion and wear, as well as decorative properties. Nickel and nickel alloys, however, can

Increase the surface hardness of the respective substrate.

The production of the respective coatings with the desired properties depends, especially under economic and economic aspects, on various parameters such as the type and composition of the electrolyte, its metal salt concentration and temperature, the geometric arrangement of the electrolysis cells and their electrodes, the electrochemical current flow and their Amount, time and polarity, strongly dependent.

The electrolytic coating of metallic strips is carried out in the prior art by means of direct current, the thyristor technology being used here. This so-called DC electrolysis can be designed to be unipolar and partially reversible, but does not allow any specific current sequences in terms of amount, time and polarity.

The object of the present invention is therefore an improved method and an improved system for the electrolytic coating of electrically conductive strips and / or electrically conductive strip-shaped fabrics with a coating based on a metal and / or a semimetal selected from group 6 to 15 and / or a mixture thereof.

According to the invention, the object is achieved by a method with the features of patent claim 1 and a system with the features of patent claim 12. With regard to the method according to the invention, it is provided that the electrically conductive tape and / or the electrically conductive tape-shaped fabric, preferably a metallic tape, a plastic tape, a glass fiber fabric tape, a carbon mesh fabric tape and / or a

Composite material thereof, after possibly prior cleaning and / or activation, is fed to a coating section comprising at least one, preferably at least two or more, electrolytic cell (s) and is successively electrolytically coated in this, the electrically conductive strip and / or the strip-shaped fabric is first connected cathodically via at least one current roller and is guided within the at least one electrolytic cell at a defined distance parallel to the at least one anode arranged in the electrolytic cell. According to the invention, the at least one anode is modulated by means of a

The coating process takes place within the coating section using a defined pulse pattern sequence, which is formed from at least one pulse pattern, with at least one of the metals and / or one of the semi-metals selected from group 6 to 15 and / or a mixture according to the pulse pattern sequence from which an electrolyte is deposited on the electrically conductive tape and / or tape-shaped fabric and the coating is formed.

In the same way, the present invention provides an installation for the electrolytic coating of an electrically conductive strip and / or an electrically conductive strip-shaped fabric. The system optionally includes a cleaning and / or an activation unit in which the electrically conductive tape and / or fabric can be cleaned and / or activated; a coating line with at least one, preferably at least two or more electrolytic cell (s), in which the electrically conductive tape and / or fabric can be successively coated electrolytically, and at least one power roller over which the electrically conductive Tape and / or tape-like tissue can be connected cathodically, the at least one electrolysis cell comprising at least one anode which is arranged such that the electrically conductive tape and / or tape-like tissue that can be passed through the at least one electrolysis cell is at a defined and parallel distance from the at least one anode can be carried out.

According to the invention, the system comprises at least one pulse rectifier which is implemented using switched-mode power supply technology, the negative pole of which is electrically connected to the at least one current roller and the positive pole is electrically connected to the at least one anode, in such a way that the at least one anode can be energized by means of a modulated current, that the coating process can be carried out within the coating section using a defined pulse pattern sequence, the pulse pattern sequence being formed from individual pulse patterns, with at least one of the metals and / or one of the semimetals selected from group 6 to 15 and / or a mixture thereof according to the pulse pattern sequence can be deposited from an electrolyte on the electrically conductive tape and / or the tape-shaped fabric.

The use of a pulse rectifier allows the amount, the temporal progression and the polarity of the respective desired pulse pattern and thus the entire pulse pattern sequence to be defined so that the electrolytic process can be optimally adapted to the respective system according to the specified parameters. For this purpose, it is provided according to the invention that the coating process takes place within the coating section using a defined pulse pattern sequence that is formed from individual pulse patterns. The pulse pattern sequence can be formed from a single pulse pattern and / or from a combination of at least two or a plurality of identical and / or different pulse patterns of a pulse pattern collection. For example, changing the polarity allows the deposition process to be reversed. By changing the polarity, for example, those Regions of the (partially) coated substrate are corrected which in the previous cathodic coating step and / or coating process as a result of high current densities, for example at the edges of the substrate, have an excessive layer thickness or dendritic crystal growth compared to the other regions. The change in polarity or the anodic operation thus allows a targeted reduction of this local elevation and adjustment of the layer thickness of this to the surrounding areas.

Furthermore, the electrolytic process can be designed using the modulated current in such a way that particularly compact, dense, pure, homogeneous, finely crystalline, pore-free, crack-free and dendrite-free coatings can be realized. In addition, the electrically conductive tape and / or tape-like fabric to be coated can be coated over its entire surface with a homogeneous layer thickness in the continuous coating process, which runs evenly over the tape width (edge effect) and has no partial overcoating and / or undercoating. As a result, the complex use of edge masks can advantageously be dispensed with. Furthermore, the use of a modulated current in bipolar operation leads to a multilayer structure with improved properties. Through the choice of the pulse pattern, the nucleation, its number and distribution on the electrically conductive tape and / or tape-shaped tissue can be positively influenced in a targeted manner, which leads to advantageous crystal growth. The Nernst diffusion layer can also be split up by repeating pulse patterns, which leads to an improvement in the mass transport properties at the cathode, i.e. the electrically conductive tape and / or tape-like tissue connected to the cathode, and manifests itself in the deposition of less rough coatings, increasing their gloss and making them denser Coatings and thus leads to an increase in corrosion resistance. By forming pre-pulses, which are briefly in time but above the average current density, the metal ions and / or semimetal ions can be transported in higher numbers to the cathodically connected strip and / or strip-shaped tissue, which leads to a finer-grained morphology of the coating and through the high current pulse possible

Competitive reactions at the cathode, such as the evolution of hydrogen, are suppressed. At the same time, this is associated with an increase in efficiency or a higher current yield for the deposition process. In particular, the high generation of hydrogen proves to be particularly problematic in the electrolytic coating processes known from the prior art, since the hydrogen diffusing into the metallic strip has a massive negative effect on the product properties of the metallic strip in the subsequent production steps. The diffusing hydrogen is primarily responsible for the so-called spontaneous brittle fracture and the lowering of the material yield point or the required strength of a metallic strip, in particular a steel strip. Furthermore, the hydrogen trapped in a coated steel strip, especially in the case of galvanized steel strips, leads to the effusion of the trapped hydrogen during the curing process of a painted component, with the result that hydrogen bubbles form beneath the paint layer, which lead to so-called “paint bursts”. An exemplary painting process includes the KTL process.

The hydrogen-related decrease in material strength, in particular of steel strips with a strength in the range of R _e ^ 500 to <2000 MPa yield point, represents a further significant process disadvantage in the prior art, because if the strength of the material is no longer given, this is for an application in the area of safety-relevant components is usually unusable. By means of the method according to the invention, the formation and diffusion of hydrogen during the coating process can be effectively reduced. A by means of the method according to the invention with Steel strip coated with a zinc and / or zinc alloy coating can therefore be produced directly while maintaining strength. It is thus possible to save on a possibly required heating process step downstream of the coating process.

Furthermore, the method according to the invention allows a multi-layer structure of a coating via the combination of different pulse patterns, preferably in electrolysis cells running through one another. Thus, one or more different morphologies of a deposition metal and / or deposition semimetal can be deposited on the same strip-shaped substrate, each with different properties. For example, a layer close to the substrate with higher adhesion can be deposited first and then a layer remote from the substrate with higher hardness. Further advantageous refinements of the invention are specified in the dependent claims. The features listed individually in the dependently formulated claims can be combined with one another in a technologically meaningful manner and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented. In this context, it is pointed out that all of the device features in question, which are explained in the course of the individual process steps or vice versa, can be combined in the same way with the system according to the invention and / or the process without explicit reference to them.

The term metal and / or semi-metal, which can be selected individually or in combination from one of groups 6 to 15, includes the metals or semi-metals known in electroplating, in particular chromium (Cr), manganese (Mn), rhenium ( Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), gold (Au), silver (Ag), zinc (Zn), cadmium (Cd), aluminum (AI), gallium (Ga), indium (In), thallium (TI), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi) and / or mixtures or alloys thereof. The coating section of the system can in principle comprise an electrolysis cell with an anode, which is designed, for example, in the form of a plate anode. In one development, the only one electrolysis cell can comprise two anodes, which are arranged one behind the other in the direction of belt travel, for example, in such a way that the strip-shaped substrate can be coated on one side. In a preferred embodiment variant, the two anodes can be formed in an anode arrangement in which the two anodes are then arranged parallel to one another within the one electrolysis cell.

In a preferred embodiment variant, the coating line comprises at least two electrolysis cells, more preferably at least three electrolysis cells, even more preferably at least four electrolysis cells, further preferably at least five electrolysis cells, and for reasons of process economy it is limited to a maximum of twenty electrolysis cells, preferably a maximum of 16, more preferably a maximum of 15 Electrolysis cells limited. The plurality of electrolysis cells are preferably arranged one behind the other in the direction of travel of the strip, through which the electrically conductive strip and / or strip-shaped fabric is then guided within the coating section.

The individual electrolysis cells can be designed in the form of horizontally or preferably in the form of vertically designed electrolysis cells through which the corresponding substrate to be coated is guided over deflection rollers.

The deposition process within the individual electrolysis cells takes place in an electrolyte through which the electrically conductive tape and / or tape-shaped fabric is passed. The electrolyte medium is usually aqueous and usually has a pH value of less than 5.0. Alternatively this can Electrolyte medium can also be formed from a non-aqueous medium such as an ionic liquid. A preferred ionic liquid comprises a mixture of choline chloride and flarnea. The modulated current is provided by a pulse rectifier that uses switched-mode power supply technology. A pulse rectifier designed in this way is defined in that the mains-side alternating voltage is first rectified and smoothed. The then generated DC voltage, which has significantly higher frequencies, usually in the range from 5 kFIz to 300 kHz, is then divided, transformed with this high frequency and then rectified and filtered. The superimposed voltage and current regulation usually works via pulse width modulation or pulse phase modulation. Due to the high frequency at the power transmitter, the transformer is made much smaller so that the energy losses are much lower. Depending on the system, this results in a significantly higher rate

Performance effectiveness of the direct current supply and thus of the entire production plant.

Depending on the design, the pulse rectifier can be made available in a modular design. This leads to a significantly higher availability, since the performance to be provided by a defective module can be taken over by another module and when a defective module is repaired, it can be quickly replaced.

Another advantage is that the quality of the direct current, in particular its lower residual ripple, is much better with lower losses than with conventional thyristor-based DC electrolysis, the repair of defective devices is much faster and easier, and existing direct current / DC voltage supply systems further modules can be retrofitted by using appropriate control technology, by means of which the output of the DC / DC voltage supply system can be increased. The at least one pulse rectifier, which provides the modulated current, is advantageously electrically connected via its negative pole to the at least one current roller and the positive pole to the at least one anode. In this context it is preferably provided that the at least one pulse rectifier, particularly preferably each of the pulse rectifiers within the coating path, is electrically connected to a central control unit via which the entire coating process is regulated. The at least one pulse pattern of the pulse pattern sequence is transmitted via the control unit to the at least one, preferably each, pulse rectifier, which transmits this signal to the respective associated electrolysis cell.

Usually, a pulse pattern of the pulse pattern sequence comprises at least one cathodic pulse, at least one anodic pulse, and / or at least one pulse off-time, the cathodic and anodic pulse being defined by a pulse duration and its respective shape, for example rectangular.

The at least one anode is preferably designed as a plate anode. Such plate anodes can in principle be designed in the form of a soluble or an insoluble anode. In the case of soluble anodes, which are also known as active anode systems, the anode dissolves during the electrolysis. In contrast, insoluble anodes, also known as inert anode systems, do not go into solution during electrolysis. Insoluble anodes consist of a carrier material on the one hand and a coating applied to it, which can be referred to as an active layer, on the other hand. Titanium, niobium or other reaction carrier metals are usually used as the carrier material, but in any case those materials which passivate under the electrolysis conditions. As a material for the active layer Electron-conducting materials such as platinum, iridium or other noble metals, their mixed oxides or compounds of these elements are usually used. The active layer can either be applied directly to the surface of the carrier material or it can be located on a substrate arranged at a distance from the carrier material. Materials which can be used as carrier material, for example titanium, niobium or the like, can also serve as the substrate.

The at least one anode can preferably be formed in one piece and / or, according to an advantageous embodiment variant, from at least two or more rod-shaped partial anodes, each of the partial anodes then being electrically connected to the power source. The at least two or more rod-shaped partial anodes are advantageously arranged in such a way that the distance between each partial anode and the strip can be adjusted across its width. As a result, locally different layer thicknesses can be applied and / or corrected by desorption along the bandwidth of the substrate, i.e. the electrically conductive tape and / or tape-like fabric, by setting the distance of each of the sub-anodes to the tape and / or the current density via the pulse rectifier . For example, the partial anodes arranged on the strip edges can be supplied with a lower current density than those arranged in the middle segment and / or positioned a greater distance from the strip in order to control the deposition of the metal and / or the semi-metal at the strip edges . In a particularly advantageous embodiment variant, the at least one electrolysis cell comprises at least one anode arrangement made up of two anodes arranged parallel to one another, through which the electrically conductive tape and / or tape-shaped fabric is guided. In a configuration designed in this way, it is preferably provided that each of the anodes of the at least one anode arrangement is energized via a separate pulse rectifier, in such a way that each of the anodes has a positive pole of each pulse rectifier and the negative pole of each pulse rectifier is electrically connected to the at least one power roller. In other words, the electrolytic cell in this configuration comprises two anodes, two pulse rectifiers and a current roller, via which the strip substrate is connected cathodically.

In a further preferred embodiment variant, the at least one electrolysis cell comprises at least two anode arrangements, each with two anodes arranged parallel to one another, through which the electrically conductive tape and / or tape-shaped fabric is guided. If such an electrolysis cell is designed as an immersion tank, it is particularly preferred that the electrically conductive tape and / or tape-like fabric is deflected between the at least two anode arrangements via a deflection roller, possibly arranged within the electrolysis cell. In a configuration designed in this way, each of the anodes of the at least two anode arrangement is also supplied with current via a separate pulse rectifier, so that a total of four pulse rectifiers are provided in this configuration. Each of the four anodes is electrically connected to a positive pole of each pulse rectifier and the negative pole of two pulse rectifiers is electrically connected to one of the two current rollers. In other words, the electrolysis cell in this configuration comprises four anodes, four pulse rectifiers, two current rollers and a deflection roller, possibly arranged within the electrolysis cell.

In a further preferred embodiment variant, the electrolysis cell can essentially be formed from the anode arrangement in that the two open flanks of this are closed. The strip substrate is guided through the partially closed space delimited by the anode arrangement and the electrolyte flows around it in this space. The electrolyte can, for example, be supplied to the space over the entire cross section via appropriate pumps and flow through it. Such a structure has a smaller installation space than an immersion tank and therefore requires smaller volumes of the electrolyte. In a particularly preferred embodiment variant, the

Coating section a plurality of electrolysis cells arranged one behind the other in the direction of travel of the strip, through which the electrically conductive strip and / or strip-shaped fabric is guided. In this context, it is advantageously provided that the electrically conductive tape and / or tape-shaped fabric is deflected between at least two, more preferably between each of the plurality of electrolysis cells, via at least one deflection roller designed as an intermediate current roller, and optionally also connected cathodically. In an exemplary embodiment variant with two electrolysis cells each comprising two anode arrangements, each of the anodes of the four anode arrangements is also supplied with current via a separate pulse rectifier, so that a total of eight pulse rectifiers are provided in this configuration. Each of the eight anodes is electrically connected to a positive pole of each pulse rectifier. With regard to the cathodic circuit, it is provided that it is distributed over a total of three current rollers, in such a way that the negative pole of two pulse rectifiers each with one of the two outer current rollers (strip inlet current roller and strip outlet current roller) and the negative pole of the other four pulse rectifiers is electrically connected to the deflecting roller designed as an intermediate current roller.

The invention and the technical environment are explained in more detail below with the aid of figures and examples. It should be pointed out that the invention is not intended to be restricted by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description and / or figures. In particular, it should be pointed out that the figures and in particular the size relationships shown are only schematic. The same reference symbols denote the same items, so that if necessary Explanations from other figures can be used in addition. Show it:

1 shows a first embodiment variant of a part of a coating section of a system for electrolytically coating an electrically conductive strip and / or strip-shaped fabric with a coating in a schematic representation,

2 shows a second embodiment variant of a part of the coating section of the system for electrolytically coating an electrically conductive strip and / or strip-shaped fabric with a coating in a schematic representation,

3 shows an embodiment variant of a part of the coating section with n-cells,

4 shows a variant embodiment of a partial anode arrangement,

5 shows a third embodiment variant of a part of the coating section of the system for electrolytically coating an electrically conductive strip and / or strip-shaped fabric with a coating in a schematic representation,

6 shows a first variant embodiment of a pulse pattern which can form part of the pulse pattern sequence,

7 shows a second embodiment variant of a pulse pattern that can form part of the pulse pattern sequence, FIG. 8 shows a third embodiment variant of a pulse pattern that can form part of the pulse pattern sequence, 9 shows a fourth variant embodiment of a pulse pattern which can form part of the pulse pattern sequence, FIG. 10 shows a fifth variant embodiment of a pulse pattern which can form part of the pulse pattern sequence, and

11 shows a sixth variant embodiment of a pulse pattern which can form part of the pulse pattern sequence

In FIG. 1, part of a coating line 1 of a system for the electrolytic coating of an electrically conductive strip and / or a strip-shaped fabric with a coating is shown in a schematic representation. Depending on the tape substrate, such a system can have one or more flasher devices for unwinding and winding up the tapes to be coated, an infeed store, a straightener, a cleaning and activation unit, the coating line 1, a post-treatment unit, an outfeed store, an inspection line and one in front of the winding station (Flaspeleinrichtung) arranged oiling device comprise.

According to the coating line 1 shown here, an electrically conductive band and / or a band-shaped fabric 2, such as a metallic band, a steel band, an aluminum band, a plastic band, a plastic film, a glass fiber fabric, a carbon mesh fabric and / or a composite material thereof with a Coating based on a metal and / or a semi-metal selected from group 6 to 15 and / or a mixture or alloy thereof can be electrolytically coated. For this purpose, the coating line 1 in the variant shown in FIG. 1 comprises an electrolysis cell 3, which in the present case is designed as an immersion tank and has a correspondingly electrochemically adjusted electrolyte 4 containing the (semi) metallic component in cationic form. For example A sulfuric acid, aqueous electrolyte with a concentration of 100 to 400 g / L ZnSC can be used to coat a steel strip with zinc.

In the embodiment variant shown here, the electrolytic cell 3 comprises two anodes 5, which are positioned in the electrolytic cell 3 in such a way that the strip 2 to be coated, which can be passed through the electrolytic cell 3, can be passed through at a defined and parallel distance therefrom. Both anodes 5 are designed as one-piece plate anodes and are arranged one behind the other in the direction of travel R of the belt, such that the belt 2 can be coated on one side.

The electrolytic cell 3 is assigned two current rollers 6, 7, with the first current roller 6 being arranged within the coating section 1 on the inlet side (strip inlet current roller) of the electrolytic cell 3 and the second current roller 7 on the outlet side (strip outlet current roller) of the electrolytic cell 3. The strip 2, which may have been subjected to a previous cleaning and / or activation step, is deflected from a horizontal movement into a vertical movement via the strip infeed current roller 6, so that it enters the electrolytic cell 3, and at the same time connected to the cathode . About the tape outlet current roller 7, the tape 2 is then after

The coating process is diverted from the vertical back to the horizontal movement, whereby it can optionally also be connected cathodically via the strip outlet current roller 7. In addition, a deflection roller 8 is arranged within the electrolysis cell 3, via which the strip 2 is deflected.

To carry out the coating process, both anodes 5 are energized by means of a modulated current which is provided by a separate pulse rectifier 9, which is implemented using switched-mode power supply technology. Each of the pulse rectifiers 9 is electrically connected to one of the two current rollers 6, 7 via its negative pole and the positive pole is electrically connected to one of the two anodes 5. The two anodes 5 are connected to the modulated current Can be energized in such a way that the coating process can be carried out using a defined pulse pattern sequence 10 which is formed from individual pulse patterns 11. Both pulse rectifiers 9 are advantageously electrically connected to a central control unit 12, via which the respective desired pulse pattern 13 of the pulse pattern sequence 12 can be transmitted to each of the pulse rectifiers 10, 11. This allows the entire coating process to be regulated in an automated manner

In FIG. 2, a second variant of a part of the coating line 1 is shown. In contrast to the variant embodiment shown in FIG. 1, the electrolytic cell 3 comprises two anode arrangements 13, each with two anodes 5 arranged parallel to one another, through which the strip 2 is guided. As can be seen from FIG. 2, each of the anodes 5 of the two anode arrangements 13 is also supplied with current via a separate pulse rectifier 9. Here, each of the four anodes 5 is electrically connected to a positive pole of each pulse rectifier 9 and the negative pole of two pulse rectifiers 9 is electrically connected to one of the two current rollers 6 and 7, respectively.

FIG. 3 shows a variant of a part of a coating line 1 with n-type electrolysis cells 3, four of which are shown by way of example. All of these electrolysis cells 3 are arranged one behind the other in the direction R of the strip. Here, between each of the plurality of electrolytic cells 3, a deflecting roller designed as an intermediate current roller 14 is arranged, via which the strip 2 is deflected from a previous to the next electrolytic cell 3 and is additionally connected cathodically. As can be seen from FIG. 3, each of the anodes 5 of the plurality of anode arrangements 13 is supplied with current via a separate pulse rectifier 9. Here, each of the anodes 5 is electrically connected to a positive pole of each pulse rectifier 9. With regard to the cathodic circuit, it is provided that it relates to the different power rollers 6, 7, 14 distributed in such a way that the negative pole of two pulse rectifiers 9 each with one of the two outer power rollers 6, 7 (strip inlet or strip outlet current roller) and the negative pole of the other pulse rectifiers 9 with the one designed as an intermediate current roller 14 Pulley is electrically connected.

FIG. 4 shows a variant of a partial anode arrangement 15 which comprises a plurality of rod-shaped partial anodes 16, each of the partial anodes 16 being electrically connected to the power source or to a negative pole of a pulse rectifier 9.

In Figure 5 is a third variant embodiment of part of a

Coating line 1 shown. In this case, the electrolysis cell 3 is essentially formed from the anode arrangement 13 in that the two open flanks of this are closed. The strip 2 is guided through the partially closed space delimited by the anode arrangement 13 and the electrolyte 4 flows around it in this space. The electrolyte 4 is conveyed from a reservoir 17 arranged below the anode arrangement 13 via a pump 18 into the space, where it flows through it over the entire cross section.

In FIGS. 6 to 11, different embodiment variants of pulse patterns 11 are shown, which form part of the pulse pattern sequence 10 according to which the coating process takes place within the coating section 1. In Figure 6, an initial current pulse of the time length t is shown, which is then reduced to a constant current strength. The initial current pulse can be used to increase the number of nuclei on the cathode, with the result that fine and small crystal forms are deposited. In contrast to this, the dashed line in FIGS. 6 to 11 shows a cathodic current that is constant over time, as is used in direct current electrolysis (DC electrolysis). FIG. 7 shows a pulse pattern 11 which initially has a high bias current pulse, which is followed by a first, higher, and a second, lower, constant amount of current. After a time t, the polarity of the current is reversed so that the cathode is operated anodically. As a result, crystal tips or a (semi-) metal deposited with inferior quality dendritically and / or excessive layers at points of high current density (edge effect) can be reversibly and specifically degraded, so that when the cathodic application is followed, higher deposition rates can be suppressed or mitigated again at locations with high current density .

In FIG. 8, an embodiment variant is shown which shows a repetitive pulse pattern 11 of identical design in terms of current amount and time. The pauses in the current flow result in a relaxation of the Nernst double layer, which is associated with a breakdown of the diffusion layer that hinders the transport of substances and thus supports the formation of a homogeneous coating thickness over the surface of the strip.

In FIG. 9, a pulse pattern 11 is shown which has two consecutive, higher current pulses which are used cyclically within the pulse pattern 11 in order to minimize and / or suppress dendritic crystal growth.

FIG. 10 shows a pulse pattern 11 which shows high current pulses, phases of cathodic deposition, and an inversion of the current and thus the connection of the cathode to the anode. This results in a breakdown of crystal tips, and in particular the breakdown of deposited (semi) metal at edge effects as well as the inhibition of this effect when the cathode is switched again by two pulses that differ in terms of time and amount of current, which affect the kinetics of the crystal transformation or (slowly or spontaneously occurring crystal transformations) (semi-) metal dissolutions are adapted, achieved. FIG. 11 shows a pulse pattern 11 with a periodic, square-wave current pulse which can be used in combination with one of the preceding pulse patterns to form a multilayer, cathodic coating. In this case, the coating is galvanically deposited on the strip in the cathodic phase, then applied anodically by the reverse pulse with currents lower in magnitude, and the deposition is prevented. As a result of the anodic switching time, crystal peaks are preferably broken down and, again by cathodic switching, another (semi) metal layer is deposited on the existing layer. By means of the pulse pattern shown in FIG. 11, the (semi-) metallic coatings can be built up periodically and in layers, which is associated with an improvement in the corrosion resistance. This so-called reverse pulse current method is also called the bipolar pulse current method, since the cathodic and anodic current conduction is changed, i.e. the current flow is changed with the intersection of the zero crossing. In other words, the cathode is temporarily switched to the anode, so that the galvanic deposition process can temporarily be carried out reversibly. The amount of current, the duration and the polarity change can be designed according to the specifications by the user and optimized for the process.

List of reference symbols

1 coating line

2 tape / fabric / cathode

3 electrolytic cell

4 electrolyte

5 anode

6 first power roller / tape infeed power roller

7 Second power roller / belt exit power roller

8 pulley

9 pulse rectifiers

10 pulse pattern sequence 11 pulse pattern 12 control unit

13 Anode arrangement

14 Intermediate current role

15 Partial anode arrangement

16 partial anodes

17 reservoir

18 pumps

R direction of tape travel

Claims

Patent claims:

1 . Method for the electrolytic coating of an electrically conductive tape and / or tape-shaped fabric (2), in particular a metallic tape, a plastic tape, a glass fiber fabric, a carbon mesh fabric and / or a composite material thereof, with a coating based on a metal and / or a semimetal from group 6 to 15 and / or a mixture thereof, wherein the electrically conductive tape and / or tape-shaped fabric (2), after possibly prior cleaning and / or activation, comprises a coating section (1) comprising at least one, preferably at least two or more, electrolytic cell (s) (3) is supplied and is successively electrolytically coated in this, the electrically conductive tape and / or tape-shaped fabric (2) initially connected cathodically via at least one current roller (6) and inside the at least one electrolytic cell (3 ) at a defined distance parallel to at least one in the electrolytic cell (3) ordered anode (5), the at least one anode (5) being energized by means of a modulated current and the coating process within the coating section (1) using a defined pulse pattern sequence (10) formed from at least one pulse pattern (11) is, according to the pulse pattern sequence (10) at least one of the metals and / or one of the semi-metals selected from the group 6 to 15 and / or a mixture thereof from an electrolyte (4) on the electrically conductive tape and / or tape-shaped fabric (2 ) is deposited and the coating is formed.

2. The method according to claim 1, wherein the modulated current of at least one pulse rectifier (9) is provided, the negative pole with the at least one current roller (7) and the positive pole is electrically connected to the at least one anode (5).

3. The method according to claim 2, wherein the at least one pulse rectifier (9) is electrically connected to a central control unit (12) via which the coating process is controlled and / or regulated.

4. The method of claim 3, wherein the at least one pulse pattern (11) of the pulse pattern sequence (10) is transmitted from the central control unit (12) to the at least one pulse rectifier (9), preferably to each of the pulse rectifiers (9).

5. The method according to any one of the preceding claims, wherein the at least one pulse pattern (11) of the pulse pattern sequence (10) comprises at least one cathodic pulse, at least one anodic pulse, and / or at least one pulse timeout, and wherein the cathodic and the anodic pulse via a Pulse duration can be defined.

6. The method according to any one of the preceding claims, wherein the at least one anode (5) is designed as a plate anode, which is preferably formed in one piece and / or from at least two or more rod-shaped partial anodes (16).

7. The method according to any one of the preceding claims, wherein the electrically conductive tape and / or tape-shaped fabric (2) within the at least one electrolytic cell (3) by at least one anode arrangement (13) of two anodes (5) arranged parallel to one another, preferably by at least two anode arrangements (13), each with two anodes (5) arranged parallel to one another.

8. The method according to claim 7, wherein each of the anodes (5) of an anode arrangement (13) is energized via a separate pulse rectifier (9), such that each of the anodes (5) each with a positive pole of each pulse rectifier (9) and the The negative pole of each pulse rectifier (9) is electrically connected to the at least one current roller (6, 7).

9. The method according to claim 7 or 8, wherein the electrically conductive tape and / or fabric (2) is deflected between the at least two anode assemblies (13) via a deflection roller (8) optionally arranged within the electrolytic cell (3, 5) .

10. The method according to any one of the preceding claims, wherein the electrically conductive strip and / or strip-shaped fabric (2) is guided within the coating section (1) through a plurality of at least two electrolysis cells (3) arranged one behind the other in the strip running direction (R).

11. The method according to claim 10, wherein the electrically conductive tape and / or tape-shaped fabric (2) is deflected between the at least two electrolysis cells (3) via at least one deflection roller designed as an intermediate current roller (14), and optionally also connected cathodically.

12. Plant for the electrolytic coating of an electrically conductive tape and / or tape-shaped fabric (2), preferably a metallic tape, a plastic tape, a glass fiber fabric, a carbon mesh fabric and / or a composite material thereof, with a coating based on a metal and / or a Semi-metal selected from group 6 to 15 and / or a mixture thereof, comprising: possibly a cleaning and / or an activation unit in which the electrically conductive tape and / or tape-shaped fabric (2) can be cleaned and / or activated; a coating section (1) with at least one, preferably at least two or more electrolytic cell (s) (3), in which the electrically conductive strip and / or strip-shaped fabric (2) can be successively electrolytically coated, and at least one power roller (6) over which the electrically conductive tape and / or tape-shaped fabric (2) can be connected cathodically, wherein the at least one electrolytic cell (3) comprises at least one anode (5) which is arranged such that the at least one electrolytic cell (3) can be carried out electrically conductive tape and / or tape-shaped fabric (2) can be carried out at a defined and parallel distance to the at least one anode (5), the system comprising at least one pulse rectifier (9), the negative pole of which is electrically connected to the at least one current roller (6) and the positive pole is electrically connected to the at least one anode (5) in such a way that the at least one anode (5) is so energized by means of a modulated current It is possible that the coating process can be carried out within the coating section (1) using a defined pulse pattern sequence (10), the pulse pattern sequence (10) being formed from individual pulse patterns (11), wherein according to the pulse pattern sequence (10) at least one of the metals and / or one of the semimetals selected from group 6 to 15 and / or a mixture thereof from an electrolyte (4) can be deposited on the electrically conductive tape and / or fabric (2).