KR100867354B1 - Device for the Electrodeposition of Aluminium or Aluminium Alloys from Organometallic Electrolytes Containing Aluminium Alkyl - Google Patents

Abstract

A device for the galvanic precipitation of aluminum and/or its alloys, from electrolytes containing metal organic aluminum alkyl complexes, comprises a carrier frame with a support and transport members, a galvanizing drum, a drive unit(s) for the drum, and drum carrier arm(s). The drum comprises a material resistant to aqueous and metal organic electrolytes at temperatures up to 110 degrees C. <??>A device for the galvanic precipitation of aluminum and/or its alloys, from electrolytes containing metal organic aluminum alkyl complexes, comprises a carrier frame with a support and transport members, a galvanizing drum, a drive unit(s) for the drum, and drum carrier arm(s). The drive unit (3) is in an encapsulated gas-tight housing. The drum (13) has a perforated inner pipe (15) along its longitudinal axis, which has a side opening opposite the electrolyte feed in the electrolyte container. The drum comprises a material resistant to aqueous and metal organic electrolytes at temperatures up to 110 degrees C.

Description

Device for the Electrodeposition of Aluminum or Aluminum Alloys from Organometallic Electrolytes Containing Aluminum Alkyl}             

The invention comprises an alkyl frame consisting of a support frame having one stand and a transport bearing, at least one plating barrel, at least one plating drive unit and one or more plating holding arms. An apparatus for electrolytic precipitation of aluminum and / or aluminum alloy from an organometallic electrolyte containing aluminum.

Electroplating small areas and large volumes of material on aqueous solutions, such as nickel plating or zinc plating, is generally done in rotary perforated plating barrels made of polyethylene or polypropylene. These plating canisters are driven by an electric motor placed in a plastic housing in a supporting rack. The current transfer to the product is located on the side of the plating canister and is done through a bent copper cord, wrapped in a plasticized PVC tube, to prevent undesired epitaxial growth of the metal.

Electroprecipitation of aluminum or aluminum alloy in aqueous solution is impossible because the potential of aluminum is very low. Therefore, electroprecipitation must be performed in a water-insoluble organic system. In particular, for this purpose, an electrolyte containing alkylaluminum is used together with the organic solvents commonly used. Therefore, the deposition of sophisticated aluminum crystals and aluminum alloy layers is well performed by using anhydrous alkylorganoaluminum electrolyte system, which is an alkylaluminum compound dissolved in an aromatic hydrocarbon such as toluene.

However, plating vessels used in water-soluble electroplating are not used in organic electrolyte systems. This is related to the fact that an organic solvent is used and that the temperature at which such electroplating is carried out is from 90 to 100 ° C. At these temperatures and the corresponding organic solvents, common plating vessels used in water-soluble systems are unstable and decompose or dissolve, eventually contaminating the electrolyte. Moreover, there is also a risk that the plating can be deformed to the extent that mechanical stability is no longer maintained.

Also known in the prior art are electroplating systems for handling large volumes of material on organic matter, in particular electroplating systems for precipitation of aluminum. However, these systems have not been successful in commercialization.

The technical idea described in EP 0042403 is also included in the above case. Here, an apparatus for electrolytic precipitation of aluminum from an organic electrolyte has been described. It is an object of the invention to provide an apparatus which does not require the removal of the plating canister from the plating trough for loading and unloading. The technical idea describes the use of a device for transporting the part to be coated. The electrical transport device fills the plating vessel and extends through the gate to the inside of the plating trough, completing operation over the retractable opening of the plating vessel. The plating can be opened and closed from the outside, providing a release vessel to withstand inert gases and inert liquids to empty the plating can, which is placed underneath the plating trough and is provided through a lockable tubular connector. Connected.

The idea of the above technique is to show a plating barrel of a very complicated configuration, and it has not been successfully commercialized yet.

It is an object of the present invention to provide an apparatus for electroprecipitating aluminum from an organic electrolyte system, wherein the plating vessel in the apparatus is stable at the material and temperature used, safely runs on combustible materials, and is of good quality aluminum or aluminum It's a plating barrel that has been modified to allow alloy coating.

The purpose is that the drive unit 3 is located in a capsule hermetic housing; The plating vessel 13 is provided with a perforated inner tube with side openings located along the longitudinal axis of the plating vessel, the electrical side openings being positioned to face the electrolyte supply port in the electrolyte container directly; The electroplating cylinder 13 is achieved by an electrolytic precipitation apparatus, characterized in that it is composed of a material which is stable up to 110 ° C in an aqueous solution and an organometallic electrolyte.

By encapsulating the drive unit in an airtight housing, it is safer to drive the plating can in flammable liquids. The case of the container preferably consists of stainless steel. The drive shaft of the plating can then penetrate the walls of the housing by a sealed hermetic shaft induction device, preferably made of polytetrafluoroethylene.

In order to protect the drive motor and for further protection from infiltrating flammable organic solvents, the housing case is filled with an inert gas such as nitrogen or argon, and preferably a pressure of 0.1 to 0.3 bar is applied to the housing case. In addition. The housing also has an overpressure blow-off valve with a feed valve and a nonreturn flap.

In each loading / unloading process, an inert gas of atmospheric pressure about 0.1 to 0.2 bar higher than the default value in the blowoff valve is automatically supplied into the drive unit housing of the apparatus through the air supply valve. In each subsequent coating process, the inert gas pressure in the drive unit housing is purged and the overpressure in the housing is set again after each process. The time to be purged or the amount of inert gas purged is set by plant control.

Another problem with the plating vessel known in the prior art is the stability of the plating vessel material. Over long periods of use, conventional plating barrel materials such as polyethylene and polypropylene are unstable with the organic solvents used in aluminum coatings.

This problem is solved by using suitable plastics that are insoluble in organic solvents and reinforced with fiberglass. In a preferred manner, the plating barrel is made of glass fibers reinforced with PPS (polyphenylene sulfide) comprising at least 40% glass fibers. This ensures not only wear resistance, but also the stability of the plating vessel at operating temperatures on the electrolyte up to 110 ° C.

1 is a device for electrolytic precipitation of aluminum or aluminum alloy.

(Explanation of symbols for the main parts of the drawing)

1: stand

2: power supply rod

3: encapsulated drive motor with electrically insulated suspension

4: bearing for transportation

5: hermetic shaft induction device

6: drive gear

7: Inert gas vent in motor housing with non-return flap

8: inert gas removal valve

9: Power supply wire to allow material to be coated inside the plating holder

10: Insulation material inside the holder

11: Stainless steel plated holder with PVDF (polyvinylidene fluoride) / Halar

12: Bearing block of plating barrel

13: Plating barrel made of glass fiber reinforced with PPS (polyphenylene sulfide)

14: wall of perforated side

15: through tube

16: Flexible current carrying contacts

17: secondary anode inside

18: contact for pickup

According to a preferred embodiment, the drive gear is made of the same material as above. In addition, this material has the advantage of being stable even in dilute acids and bases, so that pretreatment and secondary treatment of the site to be plated can be done in a water-soluble system such as acids and / or bases in the same plating vessel without any movement.

Providing a through tube in the plating vessel results in improved electrolyte circulation. In electrolytic precipitation of metals from organic electrolytes, electrolyte circulation plays a very important role. This is because, due to the limited solubility of the organometallic compounds, insufficient electrolyte circulation can lead to rapid consumption of metal ions in the liquid boundary layer around the product. This leads to a poor coating quality of the material, in particular burning of the material to be coated, formation of rough and uneven layers and even decomposition of the electrolyte. In particular, this problem not only occurs in the case of alloy precipitation of aluminum, but also in the case of precipitation of pure aluminum. In order to avoid this problem, the plating cylinder of the apparatus of the invention provides a through tube having side openings facing the wall of the electrolyte container while being located along the length axis of the plating cylinder. When the inventive device is placed in an electrolyte bath, the side openings of the through tubes are placed directly facing the electrolyte supply line of the vessel wall. In this way, the injection of fresh electrolyte directly into the substrate through the through tube at high speed is carried out during the coating process, which ensures good circulation and avoids the drawbacks described above. According to a preferred embodiment, another auxiliary anode can also be placed in the through tube, which can further increase the ambient concentration of metal ions and improve the coating speed.

According to the prior art, the support arms of conventional plating cans are mostly coated with rubber and thus unstable in organic electrolyte baths. The same holds true for conventional PVC coatings of electroconductor tracks through which an electrolyte current flows. With this arrangement, consequently epitaxial growth of the metal on the power supply rod is expected. According to the invention, this problem is solved by putting the core of polyphenylene sulfide into the support arm of a steel hollow body. In the core of the insulating material is placed a power supply rod for supplying power during electrolysis. Only in the plating can the connection between the power supply rod and the product's contact bulb be made in support of the support arm. Due to this type of configuration, no additional protective measures are required to prevent the epitaxial growth of undesirable metals in the power supply rods. The support arm has no electrical potential supplied to it and is further protected against the outside by a plastic layer coated thereon, preferably thermoplastic fluorine based on PVDF (polyvinylidene fluoride) or ethylene and chlorotrifluoroethylene Made of Locarbon

1 illustrates the invention in more detail. Numeral 1 represents a support frame with a stand, which comprises the single components of the device, the plating can, the drive unit and the support arm. The support frame has a transport bearing 4 thereon, which is used to lower or raise the device in or out of each electrolyte or rinsing bath.

The support frame has a capsular drive motor 3 therein, which is suspended for electrical insulation and has an airtight shaft induction device 5. The drive gear 6, preferably made of polyphenylene sulfide, is located at the end of the shaft. The drive gear drives the plating barrel 13, which is preferably composed of glass fibers reinforced with polyphenylene sulfide. The plating barrel 13 is connected through the support frame 1 and the support arm 11. The support arm 11 is preferably made of stainless steel, hollowed out, and coated on the outside with a fluoropolymer. The empty space in the support arm 11 includes an insulating material on which the power supply rods 9 and 10 for supplying power for electrolysis are placed. Numeral 12 represents a bearing block supporting the plating barrel. The plating bin has a pierced side wall 14 and a through tube 15 that opens to it. In order to increase the electrolyte concentration around the material to be coated, an internal auxiliary anode 17 can be introduced into the plating vessel through the tube. Numeral 18 represents a pick-up contact located in the plating barrel, which pick-up contact is preferably made of copper.

Furthermore, the bent current carrying contacts 16 lie inside the plating vessel.

The number 9 represents a line for powering the material to be coated, which is insulated inside the plating holder. Numeral 7 represents the inert gas vent of the drive unit housing including a non-returnable flap.

By using the inventive device, it is possible to produce a coating of good quality aluminum or aluminum alloy. The device can also be applied to coating magnesium and magnesium alloys, in which case an electrolyte containing the corresponding alkylmagnesium is used. The device of the invention is durable and can also be used in water-soluble systems such as rinsing processes.

Claims (8)

A support frame having one stand and a bearing for transport; One perforated inner tube with side openings, located along the length axis of the plating vessel, is provided, and the electrical side openings are positioned directly facing the electrolyte supply port in the electrolyte vessel, and are 110 ° C in aqueous solution and organometallic electrolyte. At least one plating barrel 13, composed of a stable material up to and including; At least one plating barrel drive unit (3) located in the encapsulated hermetic housing; And An electroprecipitation apparatus for depositing aluminum, an aluminum alloy or aluminum and an aluminum alloy from an organometallic electrolyte containing an alkylaluminum compound on a material to be coated, which is composed of one or more plating barrel holding arms. The method of claim 1, The plating barrel 13 is polyphenylene reinforced with glass fibers of at least 40% by weight Characterized in that composed of sulfide Electrolytic Precipitation Device. The method according to claim 1 or 2, The drive unit 3 is an automatic device for purging and pressurizing an inert gas Characterized in that Electrolytic Precipitation Device. The method according to claim 1 or 2, The auxiliary anode 17 is located in the through tube 15 to increase the concentration of metal ions. Electrolytic Precipitation Device. The method according to claim 1 or 2, The drive unit 3 is characterized in that it has a drive shaft carried out by an airtight shaft induction device 5 made of polytetrafluoroethylene through the container wall of the drive unit 3. Electrolytic Precipitation Device. The method according to claim 1 or 2, The support arm 11 is a hollow body, characterized in that it is provided as a core of polyphenylene sulfide Electrolytic Precipitation Device. The method of claim 6, The outer support arm is coated with polyvinylidene fluoride or a plastic layer of thermoplastic fluorocarbons based on ethylene and chlorotrifluoroethylene Electrolytic Precipitation Device. The method of claim 6, A power supply rod for the electrolysis power source is attached to the core of polyphenylene sulfide. Characterized in that Electrolytic Precipitation Device.

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