Siemens Aktiengesellschaft

Klaus Stoger

Siegfried Birkle

Johann Gehring

Richard Dotzer

Hans De Vries

Josef Stadter

Siegried Birkle

In known devices for galvanic deposition of metal from electrolyte onto goods, wherein a galvanic drum contains electrolyte within a tank, the removal of metal undesirably deposited on the cathode contact or the replacement of used up cathode contacts from the drum has been very time-consuming and presented a contamination problem since these operations required opening of the galvanizing tank. The invention concerns a contact replacement or cleaning arrangement which can be done simply and does not necessitate undue exposure to ambient of the tank, since the used contact is removed within the tank and replaced by opening only a narrow passage through a galvanic drum axle.

Apparatus for the galvanic deposition of aluminum

Aluminized parts are anodized in an aqueous bath which contains 1050 to 1040 g per L of sulfuric acid with a density of 1.84 and optionally 1 to 100 g of a polyhydroxy alcohol and 1 to 100 g of a multibasic organic acid. The anodizing is carried out at a pH value of less than 1 with a current density of 0.5 to 3 A/dm.sup.2 at 0.degree. to 30.degree. C. The method can be used with partially aluminized parts without destroying the base material.

Bath and method for anodizing aluminized parts

Aluminum materials and aluminized parts are oxidatively anodized at a bath temperature of 0.degree. to 15.degree. C. and preferably, 0.degree. to 10.degree. C. to produce an anodized layer of aluminum oxide more than 4 microns thick, which is hard, abrasion-proof and can be stained. The anodizing is bath used while conducting air free of or low in carbon dioxide through the bath. It is free of substances which limit the oxide layer to maximally a thickness of about 1 micron (forming layer) and contains 10 to 500 g trisodium phosphate or tripotassium phosphate per liter. In partially aluminized parts, no destruction of the base material occurs during the aluminizing.

Method for anodizing aluminum materials and aluminized parts

In order to avoid smoke formation within the cover hood for the plating tank in an assembly for the electro-deposit of aluminum and contamination of charging and discharge liquid locks leading to and from the cover hood, a liquid spray chamber and a cooled condensing zone are disposed beneath a slotted cover plate leading to the interior space of the cover hood and the open ends of the individual electrolyte cell. The substrate goods and goods carriers are sprayed and cooled leaving the electro-deposit cells prior to being passed back into the interior space of the cover hood.

Device for electro-deposition of aluminum

In a tank of aluminizing electroplating cells which may contain racks for articles, operated with aprotic oxygen-free and water-free organo-aluminum electrolytes, a lining of individual segments coated with resistant materials (enamel or electrolyte-resistant plastics) is provided as an electrically insulating protective device. The outer edges of the side baffles, coated all around, are bent round toward the outside and are held together by connecting straps which are bent round toward the inside. The individual bottom segments coated all around lie on top of each other overlapping in roof tile fashion. The protective device may also include a similarly insulated band arranged all around the cell.

Electrically insulating protective device

An organometallic electrolyte for the electrodeposition of aluminum is described which exhibits high throwing power as well as high conductivity and good solubility and is commercially readily accessible. For this purpose, the invention provides an electrolyte of a formula based upon an organometallic complex of potassium, rubidium or cesium fluoride in combination with a series of organometallic aluminum compounds.

Electrolyte for the electrodeposition of aluminum

An improved galvanizing device for the galvanic precipitation of aluminum from an anhydrous, aprotic, and oxygen-free aluminum-organic electrolyte is provided. The known device having an annularly shaped galvanizing trough, which is sealed from the atmosphere and which utilizes a centrally located, rotatable support mechanism which guides the goods carriers through the electrolyte in a circular, rotating manner, and also furnishes the goods carriers with an electrical contact, is herein provided with separate charging and discharging locks attached to the galvanizing trough. Each of the locks is provided with a U-shaped fluid lock to maintain the gaseous seal and an endless chain conveyor to transport the goods carriers to and from the galvanizing trough. Additionally, the anode plates which are located in the electrolyte trough are provided with a transport rod to permit their removal and replacement in a manner similar to that utilized with the goods carriers.

Apparatus for electro-depositing aluminum

Above the electroplating trough, a lock chamber is arranged which can be flooded with protective gas and is subdivided by means of an intermediate door into an outer chamber and a main chamber. The outer chamber has an outer lock door while the main chamber is connected to the electroplating trough by an inner lock opening. In addition, a work piece transfer device is provided which can be moved between the outer chamber and the main chamber and can be operated from the outside.

Apparatus for the electrodeposition of aluminum

Articles made of ferrous, non-ferrous and light metals and alloys thereof, e.g., aluminum, beryllium, magnesium, molybdenum, steel, tantalum, titanium, tungsten, vanadium and zinc and their alloys, are pretreated before coating and surface finishing in an anhydrous, inert, aprotic liquid, and subsequently electroplated with aluminum, cadmium, indium or zinc in an aprotic organo-metal electrolyte essentially free of molecular oxygen and water and, optionally, additionally finished by anodizing, chemical oxidation or diffusion. The pretreatment may be by erosion with finely-divided abrasive particles suspended in such liquid and impinged upon the surface of the article by hydraulic jetting, or with an aprotic liquid by the liquid-drop erosion method. Alternatively, the pretreatment may be by electrolytic action in a circuit where the article serves as the anode and is immersed in an anhydrous, aprotic electrolyte. Articles so pretreated and electroplated are thereafter more readily surface-finished or mechanically shaped.

Process of mechanically shaping metal articles

Methods of coating and surface finishing articles made of metals and

Apparatus for electrodepositing aluminum from aprotic, oxygen-free and water-free organo-aluminum electrolytes in which a heatable treatment tank is closed off in an airtight manner and contains a rotatable electroplating drum with a first heatable tank for storing an aprotic oxygen-free and water-free organo-aluminum electrolyte and a second tank for storing a rinsing liquid connected to the treatment tank.

Apparatus and method for the electrodepositing of aluminum

Apparatus for electrodepositing aluminum in which an electroplating trough, which contains aprotic oxygen-free and water-free organo-aluminum electrolyte, is closed off in an airtight manner and is accessible only via a lock chamber disposed thereabove and which uses, for inserting and removing the work pieces, a detachable coupling rod carrying a frame with the articles to be electroplated permitting a strongly adhering aluminum layer to be deposited onto work pieces of any design desired with the exclusion of air.

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Nuremberg, Germany

Klaus Stoger