Device and method for separating metals and/or metal alloys from metallo-organic electrolytes

Abstract

The invention relates to a device (1) for separating metals and/or metal alloys from metallo-organic electrolytes and depositing the same on products (7), said device comprising at least one coating section (3) for coating the products (7), at least one other treatment section (2,4), and at least one lock chamber (20,40) for introducing and discharging the products (7) into and out of the device (1) essentially without permeation of oxygen and/or humidity. The inventive device is provided with at least one siphon rinsing unit (60,61) comprising a separating element (53,54) for the gas-related separation of the other sections (2,4) of the device from the coating section (3), or for sealing said other sections (2,4) in relation to the coating section (3), and at least one hood part (5) that can be flooded with an inert gas and tightly surrounds essentially the coating section (3), the at least one siphon rinsing unit (60,61), and the at least one other treatment section (2,4). The invention also relates to a corresponding method whereby products (7) are introduced into the device in such a way that there is essentially no solvent loss, said products are delivered to at least one coating section (3) essentially in a gas-tight manner, they are then coated, and delivered to at least one output section (4) essentially in an gas-tight manner, and the finished products (7) are discharged. An inert-gas atmosphere cap is provided over all of the sections (50,51,52) of the inventive device.

Description

The invention relates to a device and process for depositing metals and/or metal alloys from metal-organic electrolytes, in particular metal-organic complex salts in organic solvents, onto products and having at least one coating section for coating the products, at least one additional processing section, and at least one sluice chamber for sluicing the products into and out of the device essentially without oxygen and/or moisture penetrating.

A galvanic deposition of aluminum, magnesium, and their alloys from aqueous systems, as is customary in classical galvanotechnology, is not possible due to the very low potential of these elements. Although in the past decades there have been numerous approaches to depositing aluminum, magnesium, and their alloys from non-aqueous systems, only deposition from complexes containing aluminum or magnesium alkyls were successful on the industrial scale. Therein, electrolyte variants with correspondingly suitable process control and analytics have been used for the most varied applications with more or less success. In several cases large-scale industrial application has become possible therewith.

The metal alkyls used in the production of the individual electrolyte variants react, as is known, very vigorously with oxygen and water to form reaction products, such as, for example, alkoxy compounds or aluminum oxanes. These reaction products are no longer in the position to form additional complexes with the alkali metals or alkali halides used in the electrolyte formulas. They remain behind as soluble contaminants in the electrolyte and in so doing reduce its electrical conductivity. Likewise, the maximum usable current density is reduced with increasing concentration of these reaction products, whereby the coating process loses its cost-effectiveness and, in given cases, its good quality.

The aforementioned constellation of problems has already been investigated in a study at the Georg Simon Ohm Technical Institute in Nuremberg in 1987, with the result that the penetration of oxygen and/or moisture into a coating system in which there are alkyl-based metal-organic electrolytes should be largely avoided in order to ensure a long service lifetime of the electrolytes and optimal layer quality. Independently of the chemical or electrochemical disadvantages caused by the penetration of oxygen and water into the coating system, avoiding the penetration of oxygen and/or water into the coating system is also markedly important with regard to the reliable and safe operation of such a system, above all in regard to reliability in processing and safety in production and with regard to the environment.

In the state of the art various coating systems are known which also include in part approaches for avoiding the penetration of oxygen and/or moisture into parts of the coating system. Such a system, in which an electrolytic coating of metallic or non-metallic endless products with metals or alloys from aprotic water and oxygen-free electrolytes is provided in a continuous process, is described in DE 197 16 493 C2. For this purpose rinsing and drying processes are attached, which are intended to remove the residues of aqueous solutions. In addition to this, exiting of the coated endless products from the system via a sluice system is provided. The sluice chamber comprises a central chamber with a sealing liquid which represents a barrier for the air contained in an outer chamber. A third chamber contains an inert gas. In addition to this, regeneration circuits are provided in which all the liquids used in the processes are prepared, cleaned, and recycled.

From DE 30 23 827 C2, sealed to the outside, a tubular cell is known through which the material which is to be treated and which is contacted by cathodes can be moved in the axial direction, in particular continuously, along anodes. In order to prevent the undesired escape of the electrolyte from the tubular cell as well as to prevent the penetration of an air atmosphere into it, the tubular cell can be pressurized with a protective gas. According to this publication a sluice arrangement consisting of several chambers is also provided into which inert gas and/or an inert liquid can be introduced for mutual sealing of the individual chambers.

According to DE 199 32 524 C1, for the purpose of an electrochemical treatment, in particular for electrochemical coating of parts which are conductive or made conductive, these parts are brought into a container filled with electrolyte solution or into a rotating basket which is rotated during the treatment and thus coats all around the parts. The container is sealed gas-tight. The treatment of the parts in the basket is done without any reloading. The respective liquids or solutions are merely pumped into the container and out of it once again. For drying, the container is centrifuged each time and in so doing the residues of the electrolyte solution are centrifuged off by propelling the basket. Due to its design this system is not suitable for depositing metal-organic electrolytes.

Also From DE 41 18 416 A1 a device for coating parts, which are preferably relatively thin, is known, in which device a coating is done by bringing the parts into containers disposed so as to be adjacent to one another. In so doing, the containers or baths are in an inert gas atmosphere. In addition to this, a rinsing bath, an etching bath, and a depositing bath are provided. In arranging the various baths in a common container, sluices formed as partitions are provided which can be penetrated by the parts to be treated. For this, the penetrable partition is formed in a penetration area by a pair of rollers which are made of an elastic material, rotate around an axis, run against one another in such a manner that a tight seal is formed, and slide opposite the bordering walls of the container in such a manner that a tight seal is formed.

From these aforementioned publications devices only follow which attempt to avoid any penetration of oxygen or moisture into the device in partial areas of the respective devices. For this, merely parts of the devices are provided with, for example, rinsing and drying devices or a three-part sluice chamber.

The objective of the present invention is thus to provide a device and a process for depositing metals and/or metal alloys from metal-organic electrolytes in which safety-related problems no longer occur, and any emission of solvent from the device, and in particular any reaction of electrolyte systems used with oxygen and moisture from the ambient atmosphere of the device, can be avoided, essentially completely.

The objective is realized in a device according to the preamble of claim 1 by the fact that at least one siphon rinsing device with a separating device for gas-related separation of the other sections of the device from, or sealing of, these other sections with respect to the coating section and at least one hood component which can be flooded with inert gas and essentially tightly encloses the coating section, the at least one siphon rinsing device, and the at least one additional coating section are provided. For a process according to the preamble of claim 17 the objective is realized by the fact that an essentially solvent loss-free sluicing of the products through at least one sluice chamber into a device for depositing metals and/or metal alloys is provided, the products are transferred to at least one coating section essentially excluding gas, the products are coated in the at least one coating section, the coated products are transferred from the coating section to at least one output section essentially excluding gas via at least one siphon rinsing device, and the finished products are sluiced out via at least one additional sluice chamber, where an inert gas atmosphere bell is held up over all the sections of the device. Extensions of the invention are defined in the subordinate claims.

Thereby a device and a process for depositing metals and/or metal alloys are provided with which it is possible to reduce any carry-over of oxygen and water or moisture as well as other contaminants into the coating electrolyte in so far as possible. Thereby a long service lifetime of the coating electrolyte can be ensured. The formation of undesired reaction products, like solvent emissions, can be very sharply restricted or essentially completely prevented. A diffusion barrier for oxygen and moisture between these individual sections of the device is provided precisely by providing siphon rinsing devices with a separating device for separating the gas atmosphere into individual sections of the device and for sealing these individual sections of the device relative to one another. The gas atmosphere in the essentially tightly sealed hood component which encircles the individual sections of the device can be set so as to be optimal in each section of the device. Thereby it is also possible to prevent any migration of solvent into the electrolyte area via the gas atmosphere. Since it frequently happens that the coating electrolyte is chemically incompatible with cleaning fluids or other solvents, this separation of the gas atmospheres of the individual sections of the device has proven itself particularly advantageous. Thereby a safe and reliable operation of the system is possible. For one thing, by providing an essentially tightly sealing hood component an encapsulation of the entire atmosphere within the device, and thus a separation from the exterior atmosphere which surrounds the device, is possible. Thereby evaporating solvent can be collected before its exit from the device and recycled into the corresponding parts of the system. Contamination of the ambient air around the device can thus be essentially eliminated. For another thing, it is possible within the hood component to maintain a constant pressure which is at the same time different from that which would correspond to the pressure in the ambient atmosphere. Preferably, at least in a part of the individual sections of the hood component a slight overpressure with respect to the atmosphere which surrounds the device is maintained and monitored. Preferably, at least one pressure maintenance device for maintaining a constant pressure in the hood component and/or a slight overpressure in the hood component with respect to the outer and/or ambient atmosphere is provided. Unintentional penetration of the exterior atmosphere into the device and thus any contamination of the gas atmosphere within the device can thus be essentially avoided.

In order to be able to maintain an essentially constant pressure in the hood component, in particular in the individual hood sections, therefore in particular a slight overpressure with respect to the exterior atmosphere of the device, preferably at least one gas buffer device is provided and is connected, or can be connected, to it/them, in particular in the first and/or last section. Gas buffer devices of this type are thus preferably provided at the entrance and exit of the device since there variations in pressure can occur due to the sluicing in and sluicing out of the products. The gas buffer devices are filled if an overpressure outside of a preselectable tolerance occurs in the hood component and emptied if an underpressure outside of a preselectable tolerance occurs in the hood component, e.g. if gas atmosphere is withdrawn from the respective hood component as, for example, for flooding a sluice chamber with inert gas.

Preferably, at least one oxygen monitoring device is provided in the at least one sluice chamber and/or the sections of the hood component. Preferably, at least one device for monitoring the solvent concentration is also provided in the sluice chamber(s). Thereby it is possible to constantly monitor the oxygen and/or solvent content of the gas atmosphere in the individual sections of the device. Since the sluice chamber(s) serve to prevent the introduction of air or oxygen into the device, the oxygen content of the sluice chamber atmosphere is regularly monitored after the sluicing in of the products, the draining of the air introduced with the product in so doing, and the rinsing of the chamber with, for example, inert gas. If the sluice chamber is opened to the hood component, the oxygen content within the chamber should be as close to zero as possible so that any penetration of oxygen into the hood component as well as the other parts of the device can be avoided. The discharge of solvent from the device should also be reduced to as close to zero as possible. In order to be able to monitor the solvent content in the sluice chambers, which represent a connection of the device to the exterior atmosphere, devices for monitoring the solvent concentration are also provided there. To the extent that the oxygen and/or solvent content exceed(s) a threshold value which can be predetermined and/or set, or is set, it is possible to trigger an adaptation of the pumping times to the introduction of gas into and discharge of gas from the sluice chamber and/or an additional rinsing phase with an inert gas during pumping cycles to reduce the oxygen content in the at least one sluice chamber. For example, a longer pumping cycle for pumping out the contaminated gas atmosphere is provided. Also the inert gas atmosphere bell can be monitored with regard to its oxygen content, where the oxygen content should be as close to zero as possible. Through these measures it can be ensured in an optimal manner that the inert gas atmosphere bell of the device is contaminated with oxygen to hardly any degree, or not at all, where optimal coating results and a very high safety and reliability during the treatment of the products can be achieved.

Preferably, a cleaning and/or activation section for cleaning and/or pre-treating the surface of the products and/or at least one output section for sluicing the products out of the device are provided. Preferably, the at least one cleaning and/or activation section comprises one or more sealable treatment basins with a cleaning fluid for cleaning the products to be coated and/or an activation fluid for activating their surfaces or for producing an adhesion promoter layer. In such a cleaning and/or activation section cleaning of the raw products is advantageously possible, where an oxide-free and blank surface of the products can be produced. Thereby an optimal adhesive strength for the following coating can be ensured. In order to improve this adhesive strength still further, an adhesion promoter layer can advantageously be applied to the surface of the product in this section of the device. By providing sealable treatment basins it is possible to open them selectively when a respective product is supposed to be inserted into them. Undesired evaporation of treatment fluid into the hood atmosphere can thus be further suppressed.

Preferably, the at least one cleaning and/or activation section comprises at least one rinsing device disposed after the at least one treatment basin(s) for rinsing the pretreated products and preventing any carry-over of chemicals from the cleaning and/or activation section. Precisely when providing a siphon rinsing device following the cleaning and/or activation section, therefore before the coating section, is it logical to provide such a rinsing of the pretreated products in order to prevent any carry-over of the chemicals from the cleaning and/or activation section into the siphon rinsing device and thus subsequently into the coating electrolyte. Preferably, a solvent preparation and/or regeneration device is provided and connected to such a rinsing device. The cleaned solvent is in particular once again recycled into this siphon rinsing device, while the cleaned cleaning fluid or activation fluid or other fluid in the treatment basins disposed before this stage can be recycled into these treatment basins. For cleaning, distillation and subsequently storage of the cleaned solvent is provided.

Preferably, the at least one solvent preparation and/or regeneration device for the cleaning and/or activation section is provided in the bypass to it. Thereby a constant cleaning of the solvent and the electrolyte or other cleaning and bath fluids during the coating, or even during the pre-cleaning and also the subsequent treatment section, is possible.

Preferably, the at least one sluice chamber is also connected, or can be connected, to a solvent separation and recycling device and/or a gas oscillation system. Preferably, at least one sluice chamber is provided at the entrance of the cleaning and/or activation section and/or at least one sluice chamber is provided at the exit of the output section. Preferably, in the sluicing-in step the products are introduced into the at least one sluice chamber. In so doing, the sluice chamber is filled with the exterior atmosphere, sealed, and subsequently evacuated, therefore the exterior atmosphere is conveyed out of the chamber and it is subsequently flooded with inert gas. Thereafter in the sluicing-in step the products are introduced into a first treatment section of the device. In the sluicing-out step from the device these products are brought out of the hood atmosphere and into the sluice chamber, it is sealed, and the hood atmosphere pumped out of it and recycled into the hood section. The sluice chamber can subsequently be opened and the products taken out. Thereafter the sluice chamber is sealed once again, the penetrating exterior atmosphere drained, and the chamber flooded with inert gas. Particularly preferably, the pumped-out sluice atmosphere is prepared, where dry inert gas and cleaned solvent are recycled into the process, in particular dry inert gas into the inert gas atmosphere bell and cleaned solvent into a treatment basin. The gas oscillation system therefore includes the pumping of dry inert gas into the hood atmosphere after pumping the atmosphere of the sluice chamber out of the sluice chamber.

Therefore, since exterior atmosphere is brought in with the product to be coated during the sluicing into the sluice chamber preferably provided at the entrance to the device before the coating, and since after the products are coated they are once again brought out into the exterior atmosphere with the opening of a sluice chamber provided at the end of the device and penetration of exterior atmosphere into the sluice chamber, it has proven itself advantageous to provide a solvent separation and recycling device in the area of the sluice chamber. Precisely there, during sluicing in and sluicing out of the products, oxygen as well as moisture can penetrate into the device and evaporated solvent can escape from the device. Via preferably provided cooling devices, atmosphere pumped out of the sluice chamber and contaminated with solvent can thus be cooled and the solvent separated, collected, and recycled. In the solvent separation process the pumped-out gas is dried and can subsequently be recycled once again into the hood atmosphere. Through the solvent separation in the sluicing-out area the products can be cleaned of the solvent residues adhering to them and leave the device essentially completely dry so that solvent emissions essentially can no longer take place. Also, in the area of the sluicing out of the products, the solvent residues discharged during the pumping-out process are recondensed, collected, and subsequently recycled into the process, in particular into the last siphon rinsing device.

Preferably, the inert gas atmosphere bell is also cleaned, in particular by condensing the inert gas atmosphere and recycling the condensed-off solvent portions into their respective circuits, in particular treatment basins. Preferably, a cooling device with a condensate separation device is provided for the recovery of carried-over and/or evaporated solvent residues, in particular in the hood component and/or coating section and/or connected to the at least one sluicing chamber. Particularly preferably, the one or more cooling devices in the hood sections and/or in the hood component comprise solvent recycling devices for recycling solvents into treatment and/or coating basins and/or the at least one siphon rinsing device. Thereby it is also possible to remove solvent contaminants from the gas atmosphere in the hood component once again. The portions of solvent condensed into the cooling devices can subsequently be recycled into corresponding treatment basins of the respective hood section. Preferably, the respective cooling devices are provided in the individual hood sections since the evaporating liquids are usually each different in the individual hood sections so that the contaminants in the gas atmosphere are always different. Thus, recycling is advantageously done within the respective hood section.

Preferably, the at least one coating section comprises at least one coating basin which can be sealed to prevent uncontrolled evaporation of solvent into the hood component. In particular, at least one cooling device for condensing evaporated solvent and at least one collection device for collecting the condensed solvent are also provided in the gas space of the at least one coating basin. In addition to this, the at least one coating section can comprise at least one output rinsing device. After the coating process the products are put into the rinse bath provided in the output rinsing device in order to remove adhering electrolyte residues. To clean the rinsing bath recycling of cleaned solvent from the solvent separation and/or regeneration device is provided in particular.

Since the siphon rinsing device is provided for separating the individual sections of the device, therefore in particular of the cleaning and/or activation section, of the treatment section, and of the output section, it has proven itself advantageous to provide an essentially non-reactive solvent in these transition areas. The at least one siphon rinsing device is thus preferably filled with an inert solvent. Thereby undesired chemical reactions between mutually incompatible chemicals from the individual sections of the device can be essentially avoided. Preferably, the at least one siphon rinsing device comprises a sealable double rinsing device with a mounted partition which is oriented so that hood sections lying above are divided. By providing such a partition, which dips into the rinsing bath of the siphon device, a gas-tight separation of different hood sections of the device can be provided. In order to make possible the transport of products through the siphon rinsing device, specifically since a particular preferred transport device provided within the hood sections cannot penetrate the partition, in particular at least one transport device is disposed, or can be disposed, within the double rinsing device for traversing the products below the partition so that during the filling of the double rinsing device with a rinsing fluid the transport device is positioned below the level of the fluid. Thereby a complete immersion of the products into the rinsing fluid is ensured, whereby they can be rinsed all around and cleaned with the preferably inert rinsing fluid in order to avoid any carry-over of chemicals and/or gas atmosphere from a forward section into the following section of the device.

Preferably, in addition to this, at least one electrolyte/solvent separating device is provided in the area of the coating section. In particular the electrolyte/solvent separating device(s) comprise(s) a distillation device for distilling solvent from the electrolyte/solvent bath fluid drained from the at least one coating basin. In addition to this, devices for recycling the resulting clean solvent into the output rinsing basin and/or devices for recycling the electrolytes into the electrolyte circuit are provided.

Cleaning of the electrolyte solution, therefore of the coating solution, can thus be done in the bypass of the coating section. This cleaning device follows in particular the coating baths, where in particular clean solvent is recycled into the output rinsing basins disposed after the coating baths, and in particular electrolyte into the coating baths.

Electrolyte fluid and/or solvents are preferably conducted essentially in closed circuits. Thereby any contamination of the other baths of the device is essentially avoided. Advantageously, there is cleaning or preparation of electrolyte fluid and/or solvent and/or a rinsing fluid to avoid any carry-over of chemicals. To avoid any carry-over of electrolyte fluid adhering to the products and/or cleaning fluid and/or activation fluid, rinsings in the various rinsing devices are preferably provided in addition. These rinsing devices can be provided at various points of the device and of the coating process, in particular in the output area of the respective sections of the device.

Above all, products of any form can be coated with the devices according to the invention, therefore also products having back-cuts in which solvent can collect. Such collections cannot be removed with devices from the state of the art, on account of which a solvent coat cannot be reliably avoided with them. With the process according to the invention and the device according to the invention removal of solvent residues for products of any form is possible in a reliable manner.

For more detailed explanation of the invention an embodiment example is described in more detail with the aid of the drawing. It shows a comprehensive view of a device according to the invention for depositing metals.

The figure shows a schematic diagram as a comprehensive view of a device 1 for depositing metals and/or metal alloys. The device comprises a cleaning and/or activation section 2, a coating section 3, and an output section 4. In addition to this, it has a hood component 5 which essentially tightly encloses all three aforementioned parts. The hood component is subdivided into three sections 50, 51 52. The three hood sections are separated from one another by respective partitions 53, 54.

The cleaning and/or activation section 2 comprises a first sluice chamber 20, a first treatment basin 21, a second treatment basin 22, and a rinsing basin 23. In addition to this, the cleaning and/or activation section comprises a part of a first siphon rinsing device 60. The siphon rinsing device 60 is divided by the partition 53 into two parts so that it forms a double rinsing device, which is accessible from section 2 and section 3 but otherwise forms a diffusion barrier. All basins or rinsing devices can be sealed with individual covers 24, 25, 26, 27, 62. The sluice chamber 20 comprises a sluice door 28 which makes possible the running of products into the sluice chamber. Preferably, such products are run into the sluice chamber via a transport carriage, which is not represented in the diagram.

The sluice chamber 20 is connected to a device 70 for the recovery of solvent and a gas oscillation system 80. The device for recovery of the solvent has a cold trap 71, a valve 72, a condensate separation device 73, as well as a line 74 between the valve 72 and the sluice chamber 20, a line 75 between the cold trap 71 and the condensate separation device 73, and a solvent recycling line 76 between the condensate separation device 73 and the first treatment basin 21.

The gas oscillation system 80 comprises a vacuum pump 81 three valves 82, 83, 84, and a line 85 between the sluice chamber 20 and the first valve 82, an additional line 86 between the valve 82 and the vacuum pump 81, a line 87 between the vacuum pump 81 and the valve 83 in the recycling line to the hood component as well as an additional line 88 between the valve 83 and the hood component 50. The line 87 also leads to the valve 84 and from it an additional line 89 leads outwards into the exterior atmosphere. Through this, air can be blown out of the device.

In addition to this, a solvent preparation and/or regeneration device 90 is connected to the cleaning and/or activation section 2. The solvent preparation and/or regeneration device comprises a distillation device 91 and a condensate collecting tank 92. The distillation device is fed via a line 93 which comes from the rinsing basin 23. Between the distillation device 91 and the condensate collecting tank 92, a line 94 is also provided. The cleaning fluid cleaned in the distillation device 91 is recycled via a line 95, a pump 96, and an additional line 97 into the second treatment basin 22. Clean solvent distilled off by the distillation device can be pumped back from the condensate collecting tank 92 to the rinsing basin 23 via a line 98, a pump 99, and a line 100.

Between the rinsing basin 23 and the second treatment basin 22 an overflow line 29 is provided in addition to this in order, if necessary, to avoid an overflow of the rinsing basin in case an excess amount of solvent is recycled.

The excess solvent is then recycled into the second treatment basin 22 via the overflow line 29.

In addition to this, the hood section 50 of the cleaning and/or activation section 2 comprises a transport device 55 for traversing products 7 between the individual treatment, rinsing, and other basins. For this, the transport device comprises a transport carriage 56 which is provided in the embodiment with a hook 57 for suspending the products 7 to be coated. Here the hook 57 can be traversed fastened on the transport carriage 56 so that the products on this hook can be slowly lowered into their respective baths and can be lifted out of them.

In addition to this, the hood section 50 comprises a cooling device 58. It is represented in the figure in the form of a cooling coil. Via this cooling coil evaporated solvent can be condensed and collected in a collecting device 59 also provided in the hood section 50. In the figure the collecting device is represented in the form of a collecting trough. The solvent collected in the collecting trough or collecting device 59 can be recycled to the first coating basin 21 via a drain line 101. Thus there can be a recycling of solvent into the first as well as into the second coating basin. In principle, still more coating basins can also be provided but the figure here merely reproduces one possible embodiment. It is also possible to provide several rinsing basins. Likewise, it would be possible in principle to provide more than one sluice chamber.

In order to be able to maintain a uniform pressure within the hood section 50, despite cleaning of the gases in this hood section and despite recycling of cleaned gases, a gas buffer container 120 is provided outside of the hood component 5.

The gas buffer container 120 is connected to the interior of the hood section 50 via a line 121. Via this line 121 there is a bilateral exchange of gas between the gas buffer container and the hood section 50. Thereby it is possible to maintain a preset overpressure and above all a constant pressure within the hood section.

To check the oxygen and solvent content in the cleaning and/or activation section 2 one provides a first oxygen sensor 122 in the area of the hood section 50 as well as a second oxygen sensor 123 and a solvent concentration sensor 124 at the sluice chamber 20. All the sensors can be connected to a monitoring and control device (not shown in the figure) in order to monitor an overshoot of the set threshold values and, if necessary, to selectively adapt pumping cycles of the sluice chamber and an exchange of gases.

The coating section 3 comprises the second part of the siphon rinsing device 60 which, as mentioned above, is formed as a double rinsing device. For the transport of the products brought through the cover 62 into the siphon rinsing device 60, within the siphon rinsing device 60 a transport device 66 is provided which can comprise in particular a transport carriage, as is represented in the figure. After the transport through the siphon rinsing device the products can be taken out once again on the side of the coating section 3 through the cover 63 of the siphon rinsing device 60. The coating section 3 comprises two coating basins 30, 31 as well as an output rinsing basin 32 and a first part of an additional siphon rinsing device 61. Each of these basins is provided with covers 33, 34, 35 while the siphon rinsing device is provided with the cover 64 on the side of the coating section. In the gas space below the covers 33, 34 of the two coating basins 30, 31 cooling coils 36, 37 and collecting troughs 38, 39 are each provided in order to condense solvent which evaporates from the electrolyte during the coating and, in particular after the coating basins, to conduct it into the rinsing bath 32.

Also, the coating section 3 is provided with a cleaning device connected to the coating basins in order to clean the electrolyte in the bypass in an electrolyte/solvent separation device 110. Thereby it is ensured that no noteworthy amounts of electrolyte are carried over, whereby a substantially closed material circuit can be produced. To clean the electrolyte, fluid is conducted from the two coating basins 30, 31 to a distillation device 112 via lines 111. In addition to this, a condensate collecting tank 113 is provided which is connected to the distillation device 112 via a line 114. The cleaned electrolyte is recycled to the coating basin 30 via lines 115, 117 and a pump 116. The solvent distilled from the electrolyte/solvent mixture is collected in the condensate collecting tank 113 and recycled to the rinsing bath in the output rinsing basin 32 via a line 118, a pump 119, and a recycling line 102. Thus the rinsing bath in the output rinsing basin 32 is always provided with clean solvent. If the level in the output rinsing basin should rise too high, an overflow line 103 is provided between the output rinsing basin and the second coating basin 31. Via this overflow line the excess rinsing fluid, therefore in particular solvent, runs back into the second coating basin.

Like the cleaning and/or activation section 2, the coating section 3 also comprises a transport device 55 with a transport carriage 56 and a hook 57 in order to be able to transport the product 7 to be coated between the individual basins of the coating section. In addition to this, a cooling device 58 in the form of a cooling coil as well as a collecting trough as collecting device 59 for condensed solvent are also provided. Via a drain line 104 the collected condensed solvent is recycled to the first coating basin 30.

The outlet section 4 comprises the second part of the siphon rinsing device 61. This is, like the transport device 60, provided with a transport device 67. Via this, the products brought through the cover 64 into the siphon rinsing device are transported to the section lying on the other side of the partition 54 and having a cover 65 of the siphon rinsing device 61. The transport is done, as in the siphon rinsing device 60, below the surface of the rinsing fluid in the siphon rinsing device. Thereby an essentially complete exclusion of gas during transport of the products from the coating section into the output section is made possible.

In addition to this, the output section comprises a second sluice chamber 40 for sluicing the coated products out of the device. The sluice chamber is provided with a cover 41. In addition to this, it comprises a sluice door 42. Similarly to the sluice chamber 20 the sluice chamber 40 is also provided with a device 130 for the recovery of solvent and a gas oscillation system 140. The device for the recovery of solvent is also provided with a cold trap 131, a valve 132 between the sluice chamber 40 and the cold trap 131, a condensate separation device 133, a line 134 between the valve 132 and the sluice chamber 40, a line 135 between the condensate separation device 133 and cold trap 131, and a solvent recycling line 136 between the condensate separation device 133 and the siphon rinsing device 61.

The gas oscillation system 140 comprises a vacuum pump 141, three valves 142, 143, and 144 as well as several lines located between them. A first line 145 leads from the sluice chamber 40 to the first valve 142, a second line 146 leads from the valve 142 to the pump 141. To it, a line from the cold trap 131 also leads, as is also the case for the device 70 between the cold trap 71 and the vacuum pump 81. From the pump 141 a line 147 leads to the valve 143 and from it a recycling line 148 leads to the hood section 52. From the vacuum pump the line 147 also leads to the valve 144, via which, in particular, air from the sluice chamber 40 can be blown outwards into the environment via a line 149.

The hood section 52 also comprises a transport device 55 with a transport carriage 56 which comprises a hook 57 in order to grasp products 7 and to be able to lower them into the individual basins. Likewise, cooling coils 58 are provided as a cooling device and a collecting trough 59 is provided for the condensed solvent which can be recycled from the collecting trough via a run-off line 105 to the siphon rinsing device 61.

The output section 4 is also provided with a gas buffer container 125 and a line 126 between the interior of the hood section 52 and the gas buffer container 125. With this it can be ensured that within the output section as constant a gas pressure as possible is maintained, although, for example, by recycling dry inert gas via the line 145 an overpressure in the hood section of the output section could occur, just as an underpressure during flooding of the sluice chamber 40 with hood atmosphere from the output section after the pumping out of the exterior atmosphere following a process of sluicing finished products out of the sluice chamber 40.

Specifically because of the constant opening and closing of the output section for the sluicing out of finished products and recycling of purified gas, in order to determine, and if necessary to intervene to correct, the oxygen and solvent content within the output section in as continuous a manner as possible, and thus to avoid as much as possible any undesired solvent emission from the sluice chamber, and in order to keep the solvent loss and also hazardous exhaust gases from the device as low as possible, first and second oxygen sensors 127, 128, and a solvent concentration sensor 129 are provided., The first oxygen sensor 127 is provided in the upper hood section 52 while the second oxygen sensor 128 and the solvent concentration sensor 129 are provided at the sluice chamber 40. Also, the hood section 51 over the coating section 3 is provided with such an oxygen sensor 150.

The course of a coating with the respective regeneration steps for electrolyte, cleaning fluid, solvent, and gas atmosphere will now be described in more detail.

A product to be coated is brought into the first sluice chamber 20 via the sluice door 28. This is done in particular via a transport carriage, which is however not represented in the figure. During the process of sluicing in, the sluice chamber is inevitably filled with exterior atmosphere (air) and subsequently sealed. Thereafter the sluice chamber is evacuated via the vacuum pump 81 and the lines 85 and 86. For this, the valve 82 is opened. Since then only uncontaminated air is in the sluice chamber, it can be discharged outwards directly via the line 89 and the opened valve 84. Subsequently, the sluice chamber is flooded with inert gas from the hood section 50. Thereupon the inner cover 24, which is disposed between the sluice chamber and the hood section 50, can be opened and the product brought into the inert gas atmosphere within the hood section 50. The amount of oxygen which can penetrate into the first hood section 50 is very small since the sluice chamber can be evacuated up to a final pressure of less than 1 to 2 mbar and it is furthermore possible that intermediate rinsings with inert gas, in particular nitrogen and argon, are performed.

The amount of gas needed for the flooding, said gas being taken from the hood section 50, would presumably lead to a lowering of the pressure unless the gas buffer container is provided. In order to avoid this and also to prevent new inert gas, e.g. nitrogen, constantly having to be brought into the hood section, in which in turn traces of oxygen and water can then be found, the gas buffer container 120 is connected to the hood section 50 which holds the pressure in the hood section 50 essentially constant due to the possible change in volume.

A monitoring of the atmosphere within the hood section can be done continuously by means of the oxygen sensors. The solvent concentration is monitored via the solvent concentration sensor 124. Checking the oxygen diffusion into the system is logical, in particular with regard to the service lifetime of the electrolytes and the coating quality, but also with regard to the general reliability of processing and operational safety of the entire system.

After the product has been brought through the cover 24 into the hood section 50, the cover 24 can be closed once again and the sluice atmosphere pumped out, where an inert gas/solvent mixture is present in the sluice atmosphere and pumped out. This is done after opening the valve 72 via the line 74, whereby the inert gas/solvent mixture is conducted through the cold trap 71. After the condensation the dry inert gas obtained is recycled via the vacuum pump 81, the line 87, the then open valve 83, and the line 88 to the hood section 50. The inert gas can once again be made available to the atmosphere in the hood section 50 as cleaned gas. The excess gas volume is collected by an increase in volume in the gas buffer container 120, whereby the pressure in the hood section 50 can be held essentially constant.

The accumulating condensed solvent is introduced into the condensate separation device 73 via the line 75 and can be recycled to the first treatment basin 21 via the solvent recycling line 76, in particular in a periodically recurring manner. Subsequently, the evacuated sluice chamber is once again flooded with fresh inert gas and the door to the exterior atmosphere, namely the sluice door 28, can be opened once again in order to bring new products into the device.

Via the transport device 55 the products can be brought into the treatment basins 21, 22, which in particular contain a cleaning fluid, and can be pre-cleaned there, and in particular a blank, oxide-free surface can be produced on them in order to ensure an optimal adhesive strength in the subsequent coating. In addition to this, an adhesion promoter layer can be applied there in this basin. In order to essentially avoid the evaporation of solvent, the covers 25, 26 are provided. Likewise, the cover 27 is provided on the rinsing basins which are each preferably only opened when goods or products are brought in or out. The rinsing basin 23 disposed behind this serves the purpose of avoiding any carry-over of chemicals from the treatments basins 21, 22 into the siphon rinsing device 60, where also the carry-over into the coating electrolyte in the basins in the coating section should be avoided. The fluid of the rinsing basin 23 is regularly prepared via the solvent preparation and/or regeneration device 90 which is connected in the bypass to the cleaning and/or activation section.

After the rinsing of the pretreated product it is put into the siphon rinsing device 60 via the cover 62. Due to the partition 53 being provided, the two hood sections 50 and 51 lying above are separated from one another in a gas-tight manner but are still connected to one another by the double rinsing basins of the siphon rinsing device 60 so that products can reach through. Preferably, the fluid in the siphon rinsing devices is identical to the solvent used in the coating electrolyte. In order to avoid any reaction with cleaning fluid and/or coating electrolyte as far as possible, an inert solvent is preferably used. By providing the siphon rinsing device between the activation section 2 and the coating section 3 the advantage results that in the cleaning fluids of the cleaning and activation section those solvents can also be used which are poorly compatible with the coating electrolyte since any migration of the solvent into the electrolyte area via the gas atmosphere is prevented. A carry-over of solvent with the products to be coated is in particular also most substantially prevented by the preparation of the fluid of the rinsing basin 23 via the distillation device 91.

After lifting the products out through the cover 63 of the siphon rinsing device 60, they arrive in the coating section 3 and therein can be lifted into the coating basins 30, 31. Along with the two coating basins represented in the basins, numerous additional ones can be provided, likewise additional output rinsing basins 32, where in the figure merely one of them is represented. In order to avoid uncontrolled evaporation of solvent in the hood section 51 lying above, the covers 63, 33, 34, 35, and 64 are closed in normal operation. Preferably, the covers are only opened to run products into, or take products out of, the individual basins.

In the two coating basins 30, 31 the cooling coils 36, 37 and the collecting trough 38, 39 are each located in the gas space between the bath fluid level and the cover. Here solvent which is evaporated from the electrolyte during the coating is condensed and conducted to the rinsing bath in the output rinsing basin 32. Via the distillation device provided in the electrolyte circuit rather large amounts of electrolyte are regularly brought into reaction and pumped back once again to the basin 30 via the lines provided therein as well as the pump 116. The solvent distilled from the electrolyte is collected in the collecting tank 113 and recycled once again to the output rinsing basin 32 or to the rinsing bath contained therein via the lines and the pump 119. To avoid an overflow of the output rinsing basin 32, excess solvent is recycled into the circuit or the basin 31 via the overflow line 103. Thereby it is ensured that no noteworthy amounts of electrolyte are carried over into the siphon rinsing device 61 disposed further on, where even at this point a substantially closed material circuit can already be produced.

The connecting siphon rinsing device 61 between the coating section and the output section is comparable in structure and function to the siphon rinsing device 60. The products completely immersed therein are taken out once again through the cover 65 on the side of the output section 4. Due to the previous rinsing in the output rinsing basin 32, in which fresh solvent is contained, the electrolyte residues adhering previously from the coating section 3 are collected and not carried over into the output section 4. In addition to this, each of the output rinsing basins also serves to effectively utilize, and remove from the system, excess process heat which arises in the coating process.

In the output section 4 the second sluice chamber 40 is also provided, into which the coated product is brought. This is done via the cover 41. After stocking the sluice chamber with finally coated product, a pumping-off process is also initiated. This serves for the recovery of any solvent residues still adhering to the coated product. Thereby it is possible that the completely coated product leaves the device dry and solvent emissions essentially can take no longer place. All the solvent evaporated during the pumping off process, recondensed in the cold trap 131, and collected in the condensate separation device 133 is recycled into the siphon rinsing device 61 via the line 136. Otherwise, the sluicing-out process runs analogously to the sluicing-in process with regard to pumping in and pumping out of sluice atmosphere and inert gas. For sluicing out the sluice door 42 is opened.

The individual hood sections 50, 51, and 52 are flooded with inert gas and, at least in the present embodiment example, held, via an automatic pressure maintenance system, constantly at a slight overpressure with respect to the ambient atmosphere. Thereby any penetration of air into the hood component is avoided. The oxygen sensors 122, 123, 127, 128, and 150 continuously specify the oxygen content in the respective gas atmosphere. If an overshoot of predefined threshold values is detected, an adaptation, with respect to the pumps 81, 141, of the pumping time is performed or an additional rinsing with inert gas during the pumping cycle in the sluice chambers 20, 40 is initiated.

Also, providing the siphon rinsing devices filled with a barrier fluid, in particular inert solvent, provides for an additional increase of the barrier effect in this area, in particular in combination with the covers 62, 63, and 64, 65, whereby an additional reduction of the diffusion of oxygen and moisture into the coating section 3 can be made possible. The combination of sluice chambers, a vacuum system, a gas oscillation system, and the siphon rinsing devices provides for a very long service lifetime of the metal-organic coating electrolytes and a uniform coating quality since the formation of undesired reaction products, such as, for example, alkoxy compounds or aluminum oxanes, can be effectively restricted or essentially prevented.

By providing a solvent preparation for the cleaning and/or activation section 2 any contamination of the coating electrolytes by oxygen and moisture as well as any carry-over of other chemicals can be effectively prevented, in particular also the carry-over of solvents used in the cleaning fluids which, in given cases, are incompatible with a certain coating electrolyte. By providing the solvent preparation and/or regeneration device 90 direct recycling of cleaning fluid and solvent into the corresponding circuit can be made possible. Thereby contamination in the rinsing basin 23 can also be held to a very low level.

By condensing the hood atmosphere in the hood sections 50, 51, 52 they can be kept as dry and pure as possible. Also, any condensation of solvent residues found on the goods which evaporate during the transport time, in particular when the products are still warm, can be condensed off in a controlled manner and recycled once again into the individual material circuits via the drain lines.

Along with the embodiment example described above and represented in the drawing, numerous others can be formed in each of which it is possible to hold solvent emissions from the device as low as possible and to achieve as high as possible a reduction of the carry-over of oxygen and moisture as well as other contaminants into a coating electrolyte and thus to clearly extend the service lifetime of coating electrolytes while avoiding the formation of undesired reaction products. In particular, only one, or more than the two, treatment basins, coating basins, siphon rinsing devices, and rinsing basins can also be provided. Also, additional sections, in particular additional coating sections, can be provided. Also, the siphon rinsing device(s) can be replaced by another device with corresponding action, where furthermore a gas-related separation between sections of the device is made possible. In principle, it is also possible to configure the cleaning and/or activation section to be smaller or, in given cases, to even have it omitted entirely. In any case, the devices comprise a closed hood atmosphere which forms an essentially tight bell over the individual stations of the coating device, where at the same time there is a constant cleaning of the atmosphere as well as the treatment or coating baths and rinsing baths. This can be accomplished in a particularly simply manner by leading the cleaning sections in the bypass to the respective processing or treatment sections. Alternatively, more complex cleaning steps or circuits are possible.

List of Reference Numbers

• 1 Device
• 2 Cleaning and activation section
• 3 Coating section
• 4 Output section
• 5 Hood component
• 7 Product
• 20 First sluice chamber
• 21 First treatment basin
• 22 Second treatment basin
• 23 Rinsing basin
• 24 Cover
• 25 Cover
• 26 Cover
• 27 Cover
• 28 Sluice door
• 29 Overflow line
• 30 First coating basin
• 31 Second coating basin
• 32 Output rinsing device
• 33 Cover
• 34 Cover
• 35 Cover
• 36 Cooling coil
• 37 Cooling coil
• 38 Collecting trough
• 39 Collecting trough
• 40 Second sluice chamber
• 41 Cover
• 42 Sluice door
• 50 First hood section
• 51 Second hood section
• 52 Third hood section
• 53 Partition
• 54 Partition
• 55 Transport device
• 56 Transport carriage
• 57 Hook
• 58 Cooling device
• 59 Collecting device
• 60 First siphon rinsing device
• 61 Second siphon rinsing device
• 62 Cover
• 63 Cover
• 64 Cover
• 65 Cover
• 66 Transport device
• 67 Transport device
• 70 Device for the recovery of solvent
• 71 Cold trap
• 72 Valve
• 73 Condensate separation device
• 74 Line
• 75 Line
• 76 Solvent recovery line
• 80 Gas oscillation system
• 81 Vacuum pump
• 82 Valve
• 83 Valve
• 84 Valve
• 85 Line
• 86 Line
• 87 Line
• 88 Line
• 89 Line
• 90 Solvent preparation and/or regeneration device
• 91 Distillation device
• 92 Condensate collection tank
• 93 Line
• 94 Line
• 95 Line
• 96 Pump
• 97 Line
• 98 Line
• 99 Pump
• 100 Line
• 101 Drain line
• 102 Recycling line
• 103 Overflow line
• 104 Drain line
• 105 Drain line
• 110 Electrolyte/solvent separation device
• 111 Line
• 112 Distillation device
• 113 Condensate collection tank
• 114 Line
• 115 Line
• 116 Pump
• 117 Line
• 118 Line
• 119 Pump
• 120 Gas buffer container
• 121 Line
• 122 First oxygen sensor
• 123 Second oxygen sensor
• 124 Solvent concentration sensor
• 125 Gas buffer container
• 126 Line
• 127 First oxygen sensor
• 128 Second oxygen sensor
• 129 Solvent concentration sensor
• 130 Device for the recovery of solvent
• 131 Cold trap
• 132 Valve
• 133 Condensate separation device
• 134 Line
• 135 Line
• 136 Solvent recycling line
• 140 Gas oscillation system
• 141 Vacuum pump
• 142 Valve
• 143 Valve
• 144 Valve
• 145 Line
• 146 Line
• 147 Line
• 148 Line
• 149 Line
• 150 Oxygen sensor

Claims

1. Device for depositing metals and/or metal alloys from metal-organic electrolytes, in particular metal-organic complex salts in organic solvents, onto products, said device comprising at least one coating section for coating the products, at least one additional processing section, and at least one sluice chamber for sluicing the products into and out of the device essentially without oxygen and/or moisture penetrating, wherein at least one siphon rinsing device with a separating device for gas-related separation of the other sections of the device from, or sealing of, these other sections with respect to the coating section and at least one hood component which can be flooded with inert gas and essentially tightly encloses the coating section, the at least one siphon rinsing device, and the at least one additional coating section.

2. Device according to claim 1, wherein at least one transport device is disposed, or can be disposed, within the siphon rinsing device for traversing the products below the partition so that during the filling of the siphon rinsing device with a rinsing fluid the transport device is positioned below the level of the fluid.

3. Device according to claim 1, wherein at least one oxygen monitoring device is provided in the at least one sluice chamber and/or the sections of the hood component and/or at least one device for monitoring the solvent concentration is provided in the sluice chambers.

4. Device according to claim 3, wherein on overshoot of threshold values which can be set, or are set, the at least one oxygen monitoring device triggers an adaptation of the pumping times to the introduction of gas into and discharge of gas from the sluice chamber and/or an additional rinsing phase with an inert gas during pumping cycles to reduce the oxygen content in the at least one sluice chamber.

5. Device according to claim 1, wherein at least one pressure maintenance device for maintaining a constant pressure in the hood component and/or a slight overpressure in the hood component with respect to the outer or ambient atmosphere is provided, in particular to maintain an essentially constant pressure in the hood component and/or hood sections at least one gas buffer device is provided and is connected, or can be connected, to it/them, in particular in the first and/or last section of the device.

6. Device according to claim 1, wherein at least one cleaning and/or activation section for cleaning and/or pre-treating the surface of the products is provided.

7. Device according to claim 6, wherein the at least one cleaning and/or activation section comprises one or more sealable treatment basins with a cleaning fluid for cleaning the products to be coated and/or an activation fluid for activating their surfaces, in particular for producing an adhesion promoter layer and/or the at least one cleaning and/or activation section comprises at least one rinsing device disposed after the at least one treatment basin for rinsing the pretreated products and preventing any carry-over of chemicals from the cleaning and/or activation section.

8. Device according to claim 1, wherein the at least one coating section comprises at least one coating basin which can be sealed to prevent uncontrolled evaporation of solvent into the hood component and/or at least one output rinsing basin for rinsing the coated products.

9. Device according to claim 1, wherein at least one solvent preparation and/or regeneration device is provided, in particular the at least one solvent preparation device for the at least one cleaning and/or activation section is provided in the bypass to it.

10. Device according to claim 1, wherein the at least one sluice chamber is connected, or can be connected, to a solvent separation and recycling device and/or a gas oscillation system.

11. Device according to claim 1, wherein at least one cooling device with a condensate separation device for the recovery of carried-over and/or evaporated solvent residues is provided, in particular in the hood component and/or coating section and/or connected to the at least one sluicing chamber.

12. Device according to claim 11, wherein the one or more cooling devices in the hood sections and/or in the hood component comprise solvent recycling devices for recycling solvents into treatment and/or coating basins and/or which comprise at least one siphon rinsing device, in particular which comprise at least one cooling device for condensing evaporated solvent and at least one collection device for collecting the condensed solvent in the gas space of the at least one coating basin are provided.

13. Device according to claim 1, wherein at least one electrolyte/solvent separating device is provided in the area of the coating section, in particular the electrolyte/solvent separating device(s) comprise(s) a distillation device for distilling solvent from the electrolyte/solvent bath fluid drained from the at least one coating basin and in particular devices for recycling the clean solvent obtained into an output rinsing basin are provided.

14. Device according to claim 1, wherein at least one sluice chamber is provided at the entrance of the cleaning and/or activation section and/or at least one sluice chamber is provided at the exit of the output section for the sluicing out of products.

15. Device (1) according to claim 1, wherein the hood component (5) comprises at least one transport device for traversing the products between individual basins and devices.

16. Device (1) according to claim 1, wherein the at least one siphon rinsing device is filled with an inert solvent.

17. Process for depositing metals and/or metal alloys from metal-organic electrolytes, in particular metal-organic complex salts in organic solvents, onto products, said method comprising:

essentially solvent-free sluicing of the products through at least one sluice chamber into a device to deposit metals and/or metal alloys,

transferring the products to at least one coating section essentially excluding gas,

coating the products in the at least one coating section, transferring the coated products from the coating section via at least one siphon rinsing device to at least one output section essentially excluding gas, and

sluicing out the finished products via at least one additional sluice chamber, where an inert gas atmosphere bell is held up over all the sections of the device.

18. Process according to claim 17, wherein the products are pre-treated, in particular their surfaces are cleaned and/or activated for further treatment.

19. Process according to claim 18, wherein after the cleaning and/or the activation, the products are introduced via at least one additional siphon rinsing device essentially excluding gas into the at least one coating section.

20. Process according to claim 17, wherein electrolyte fluid and/or solvents is/are conducted in essentially closed circuits, in particular there is cleaning or preparation of electrolyte fluid and/or solvent and/or a rinsing fluid to avoid any carry-over of chemicals.

21. Process according to claim 17, wherein to avoid any carry-over of cleaning fluid and/or activation fluid and/or electrolyte fluid adhering to the products, they are rinsed in rinsing devices.

22. Process according to claim 17, wherein in the sluicing-in step the products are introduced into the at least one sluice chamber, the sluice chamber is filled with the exterior atmosphere, sealed, and subsequently evacuated, the exterior atmosphere is conveyed out of the chamber, the chamber is subsequently flooded with inert gas, and subsequently the products are brought into a first treatment section of the device.

23. Process according to claim 22, wherein the pumped-out sluice atmosphere is prepared, where dry inert gas and cleaned solvent are recycled into the process, in particular dry inert gas into the inert gas atmosphere bell and cleaned solvent into a first treatment basin.

24. Process according to claim 17, wherein the at least one sluice chamber atmosphere is monitored with regard to its oxygen and/or solvent content and/or the inert gas atmosphere bell is monitored with regard to its oxygen content, in particular on overshoot of set threshold values the discharge of contaminated atmosphere and/or introduction of cleaned inert gas atmosphere is accelerated or decelerated.

25. Process according to claim 17, wherein the gas of the inert gas atmosphere bell is also cleaned, in particular by condensing the gases and recycling the condensed-off solvent portions into their respective material circuits.