EP0049192B1 - Apparatus for anodic oxydation by the pad-plating process, and electrolyte used therefor - Google Patents

Apparatus for anodic oxydation by the pad-plating process, and electrolyte used therefor Download PDF

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Publication number
EP0049192B1
EP0049192B1 EP81401459A EP81401459A EP0049192B1 EP 0049192 B1 EP0049192 B1 EP 0049192B1 EP 81401459 A EP81401459 A EP 81401459A EP 81401459 A EP81401459 A EP 81401459A EP 0049192 B1 EP0049192 B1 EP 0049192B1
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EP
European Patent Office
Prior art keywords
electrolyte
cathode
tube
mass
gripping means
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81401459A
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German (de)
French (fr)
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EP0049192A1 (en
Inventor
François Baburek
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SOCIETE NOUVELLE DALIC
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Dalic Laboratoire SA
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Priority to AT81401459T priority Critical patent/ATE27191T1/en
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
    • C25D17/10—Electrodes, e.g. composition, counter electrode
    • C25D17/14—Electrodes, e.g. composition, counter electrode for pad-plating
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/005—Apparatus specially adapted for electrolytic conversion coating
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/10—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing organic acids

Definitions

  • the present invention relates to an improved device for anodic oxidation by buffer electrolysis, of the type in which the electrolyte is retained in an absorbent mass in contact with a cathode comprising an internal cooling circuit, connected to the negative pole of a source of electricity and carried by an electrically insulated gripping member.
  • the cathode in particular used for the anodic oxidation of aluminum and its alloys, is constituted by a graphite block comprising an interior chamber in which cooling water circulates. It is also provided with a tapping opening into said chamber and intended to receive the threaded rod of a gripping member consisting of a conductive mass covered with an insulating cap and connected to the positive pole of a source of electricity. . Finally, in the interior chamber of the cathode open a water supply conduit and a water discharge conduit, both integral with the gripping member, and which ensure a circulation of water in said chamber.
  • the object of the present invention is therefore to remedy the drawbacks mentioned above and to do this, it provides a device which is characterized in that the cathode is constituted by a stainless steel tube comprising at least two branches, the at least one of these branches being held locally by the gripping member, and the free end of one or more of these branches being connected to a supply of cooling fluid, the free end of the remaining branch (s) being connected to a coolant outlet.
  • the cathode is constituted by a stainless steel tube comprising at least two branches, the at least one of these branches being held locally by the gripping member, and the free end of one or more of these branches being connected to a supply of cooling fluid, the free end of the remaining branch (s) being connected to a coolant outlet.
  • stainless steel resist particularly well to the operating conditions required for anodic oxidation, but it is also possible to conform it to a tube whose cooling by internal circulation of a cooling fluid is extremely effective. Indeed, in anodic oxidation by buffer electrolysis, it is essential to obtain a protective coating of good quality and of sufficient thickness, to operate at temperatures as low as possible, hence the absolute need to evacuate the calories released at the cathode due to the very high current intensities applied to the latter.
  • connection between the cathode-forming tube and the negative pole is ensured by means of a conductive mass of the electric current contained in the gripping member, at least one of the branches of the tube being in contact with this conductive mass.
  • the cathode will preferably be substantially U-shaped, the two branches of which are held in the gripping member in the vicinity of their free end.
  • the resulting device is therefore compact, easy to handle and makes it possible, by choosing the length of the branches of the U-shaped tube, to treat areas of difficult or even impossible access with the devices of the prior art.
  • the cooling fluid can consist of the electrolyte, the cathode being pierced, in the vicinity of the part in contact with the absorbent mass, fine orifices for the flow of the electrolyte.
  • the cooling fluid can consist of the electrolyte, the cathode being pierced, in the vicinity of the part in contact with the absorbent mass, fine orifices for the flow of the electrolyte.
  • the device according to the invention will preferably include an electrolyte supply disposed in the vicinity of the cathode and of the absorbent mass, so that the latter can absorb the electrolyte flowing from this supply, the latter being maintained locally by the gripping member.
  • the cathode remains refrigerated by the cooling fluid which passes through it and the electrolyte comes from a source other than the cathode, a source which, when it is constituted by a stainless steel tube closed at one of its ends, pierced with fine orifices delivering passage to the electrolyte, and maintained in the gripping member in the vicinity of its free end, is intimately incorporated within the anodizing device and forms a compact whole with the latter.
  • This arrangement has the advantage over that described above, of making it possible to regulate at will the quantity of electrolyte to be poured onto the absorbent mass, without however harming re cooling of the cathode and without increasing the size of the anodizing device and complicating its structure and handling.
  • the electrolyte supply tube is disposed substantially in the longitudinal plane of symmetry of the U-shaped tube.
  • the size of the cathode-tube assembly d The supply of electrolyte is minimal and by choosing the location of the orifices suitably, it is possible to keep the absorbent mass perfectly imbibed in electrolyte at the working area of the cathode.
  • the electrolyte supply tube is located slightly above the plane formed by the two branches of the U-shaped cathode, it is possible, always by choosing the position of the orifices made in this tube, to ensure that the electrolyte flowing from these orifices spreads over one and / or the other of the branches of the cathode, thus contributing to the cooling of the latter.
  • the electrolyte supply tube may be in contact with the conductive mass of the electric current and in this case, it will also play the role of cathode and may contribute to anodic oxidation.
  • the branch or branches of the cathode in contact with the conductive mass and possibly the electrolyte supply tube are immobilized respectively in bores provided in this conductive mass. This type of assembly not only allows good electrical contact, but also gives good rigidity to the device.
  • the absorbent mass is in the form of a sleeve closed at one of its ends, fitting over all or part of the cathode portion and optionally of the electrolyte supply tube, not maintained in the gripping member.
  • the cathode-tube assembly for supplying electrolyte is thus surrounded by the absorbent mass, which prevents the electrolyte from inadvertently dripping and thus allows the anodization device to be used in any position.
  • the present invention also relates to a new type of absorbent mass, usable in particular in the anodizing device described above and below. More specifically, this absorbent mass consists of polyester wadding enclosed in a sheath made of woven polypropylene or polyester fibers.
  • this polyester in the form of wadding or woven fibers, is that resulting from the copolymerization of glycols and various aromatic diacids, and preferably that resulting from the copolymerization of glycol and terephthalic acid.
  • the polypropylene used to make the sheath will preferably be a polymer of isotactic structure of the MERAKLON type ".
  • the present invention also relates to new electrolytes for anodic oxidation by buffer electrolysis, usable in particular in the anodization device which is the subject of the present application.
  • these electrolytes consist of an aqueous solution of concentrated sulfuric acid, chromic anhydride, sulfamic acid and optionally magnesium sulfate. These are particularly suitable for the anodic oxidation of aluminum.
  • They can also contain magnesium sulphate and are therefore particularly suitable for the anodic oxidation of light aluminum alloys.
  • the device which is the subject of these figures comprises a block 1 of plastic material, of substantially frustoconical shape, provided with a handle 2, the fixing of the latter to the block 1 being ensured, for example, by simply screwing in a threaded rod (not shown) carried by the handle, in a thread (not shown) formed in said block.
  • the small base 3 of the frustoconical block 1 has an opening 4 which extends into an interior chamber in which is housed by force a cylindrical conductive mass 5, preferably made of stainless steel, and the axis of which coincides with the axis of the block frustoconical 1.
  • This mass 5 is provided with three bores (6, 7, 8) situated respectively in the extension of bores of the same section (6a, 7a, 8a) produced in block 1.
  • two of the three pairs of complementary bores (6, 6a) and (7, 7a) are substantially in the horizontal plane of symmetry of the block 1, on either side and at equal distance from the vertical plane of symmetry of this same block 1, while the third pair of complementary bores (8, 8a) is situated substantially in this vertical plane of symmetry, under the two pairs of bores (6, 6a) and (7, 7a).
  • the position in block 1 described above of these different bores is the most rational, but could be any other without this in any way modifying the spirit of the invention.
  • the pairs of bores (6, 6a) and (7, 7a) could be in a plane different from the horizontal plane of symmetry and / or in two separate planes.
  • the pair of bores (8, 8a) could be outside the vertical plane of symmetry and / or above the pairs of bores (6, 6a) and (7, 7a).
  • the mass 5 is extended, by a projection 9, towards the large base 10 of the frustoconical block 1 without however reaching this base.
  • This projection 9 is provided with a thread 11 perpendicular to the base 10 and located in the extension of a bore 12 of the same section made in the block 1 and starting from said base 10, thread which receives the threaded rod 13 of a electrical connection plug 14 capable of being connected to the negative pole of an electrical source (not shown).
  • the position of the projection 9 and the method of fixing the plug 14 on this projection could be any other without this in any way modifying the operation of the anodizing device.
  • pairs of bores (6, 6a) and (7, 7a) are forced in and so as to pass right through the block 1, respectively the two branches (15,16) of a U-shaped tube 17 made of stainless steel, which are each bent slightly in front of the base 3, the bent parts (18, 19) being slightly inclined towards each other, and extending respectively by two horizontal sections (20, 21) connecting to the bottom of the U and located in the same plane itself located below block 1.
  • the free end of the tube 15 emerging from the base 10 is intended to be connected to an inlet (not shown) in cooling fluid, for example water, the free end of the tube 16 also emerging from the base 10 being, in turn, intended to be connected to an outlet (not shown) in cooling fluid.
  • cooling fluid for example water
  • a tube 22 of stainless steel In the bore torque (8, 8a) is also forced in and so as to pass right through the block 1, a tube 22 of stainless steel also bent, the bent part 23 extending by a horizontal section 24 closed at its end and located just above the plane formed by the sections (20, 21), this section 24 being provided with two rows of fine orifices (25, 26) each facing each other respectively with said sections ( 20, 21).
  • the free end of the tube 22, that is to say that emerging from the base 10 is for its part intended to be connected to an electrolyte supply.
  • a sleeve 27 substantially cylindrical and closed at one of its ends is threaded on the sections (20, 21, 24) which are therefore totally surrounded by this sleeve.
  • the latter consists of polyester wadding 28 enclosed in a sheath 29 made of woven fibers of polypropylene MERAKLON.
  • the shape of this sleeve is not limited to the cylindrical shape, but will in fact depend on the shape of the cathode. In the embodiment described, this cathode is U-shaped, but it could be different and adapted to the geometry of the surface to be anodized.
  • the operation of the device described above is as follows.
  • the ends of the branches (15, 16) are connected respectively to an inlet and to an outlet for cooling fluid, fluid whose circulation is for example ensured by a pump.
  • the end of the tube 22 is connected to an electrolyte supply, itself connected to an electrolyte supply pump, the flow rate of which is adjustable.
  • plug 14 is connected to the negative pole of an appropriate current generator, the part to be anodized being connected to the positive pole of this same generator.
  • the generator can be of any type, for example direct current or pulsed current.
  • the actual anodization is carried out by moving this sleeve over the surface to be treated while monitoring the supply of electrolyte to compensate for evaporation and ensure that the sleeve always remains perfectly supplied with electrolyte.
  • the electrode will be refrigerated to the maximum and the electrolyte used will be at the lowest possible temperature, and preferably at a temperature equal to or lower than 20 ° C.
  • the operating voltages of the device according to the invention will generally be of the order of 25 to 50 volts, values at which the efficiency of the anodization will be substantially constant, the current densities possibly varying between 15 and 250 A / d m2 .
  • the part to be anodized may consist of any metal capable of undergoing anodic oxidation, such as for example aluminum and its light alloys, as well as titanium and its alloys.
  • the electrolytes to be used in the device according to the invention will of course depend on the nature of the metal constituting this part.
  • the electrolyte will preferably consist of an aqueous solution containing 30 to 100 g / l, and more particularly approximately 35 g / l, of sulfamic acid; 10 to 60 g / l, and more particularly approximately 17 g / l, of chromic anhydride; and 9 to 55 g / l, and more particularly approximately 13 g / l, of concentrated sulfuric acid.
  • the electrolyte will preferably consist of an aqueous solution containing 30 to 100 g / l, and more particularly about 100 g / l, sulfamic acid; 10 to 60 g / l, and more particularly approximately 48 g / l, of chromic anhydride; 9 to 55 g / l, and more particularly approximately 37 g / l, of concentrated sulfuric acid; and about 100 g / l of magnesium sulfate heptahydrate.

Description

La présente invention a pour objet un dispositif perfectionné pour l'oxydation anodique par électrolyse au tampon, du type dans lequel l'électrolyte est retenu dans une masse absorbante en contact avec une cathode comportant un circuit interne de refroidissement, reliée au pôle négatif d'une source d'électricité et portée par un organe de préhension isolé électriquement.The present invention relates to an improved device for anodic oxidation by buffer electrolysis, of the type in which the electrolyte is retained in an absorbent mass in contact with a cathode comprising an internal cooling circuit, connected to the negative pole of a source of electricity and carried by an electrically insulated gripping member.

Dans les dispositifs connus les plus élaborés de ce type, notamment utilisés pour l'oxydation anodique de l'aluminium et de ses alliages, la cathode est constituée par un bloc de graphite comportant une chambre intérieure dans laquelle circule de l'eau de refroidissement. Elle est en outre pourvue d'un taraudage débouchant dans ladite chambre et destiné à recevoir la tige filetée d'un organe de préhension constitué d'une masse conductrice recouverte d'une coiffe isolante et reliée au pôle positif d'une source d'électricité. Enfin, dans la chambre intérieure de la cathode débouchent un conduit d'amenée d'eau et un conduit d'évacuation d'eau, tous deux solidaires de l'organe de préhension, et qui assurent une circulation d'eau dans ladite chambre.In the most sophisticated known devices of this type, in particular used for the anodic oxidation of aluminum and its alloys, the cathode is constituted by a graphite block comprising an interior chamber in which cooling water circulates. It is also provided with a tapping opening into said chamber and intended to receive the threaded rod of a gripping member consisting of a conductive mass covered with an insulating cap and connected to the positive pole of a source of electricity. . Finally, in the interior chamber of the cathode open a water supply conduit and a water discharge conduit, both integral with the gripping member, and which ensure a circulation of water in said chamber.

Le graphite étant un matériau poreux, il est malheureusement nécessaire de procéder à une opération fastidieuse d'étanchement des parois de la chambre intérieure de la cathode au moyen de résines imperméables. En outre, cet étanchement n'étant pas possible au niveau du taraudage, il existe des possibilités de fuite de l'eau de refroidissement à ce niveau, ce qui limite fortement la pression que l'on peut conférer à cette eau, et donc son débit, et par voie de conséquence le refroidissement. D'autre part, la cathode en graphite résiste assez mal dans le temps, aux conditions très sévères de température, d'acidité et de tension et d'intensité électrique auxquelles elle est soumise au cours de l'oxydation anodique. Il s'ensuit que des changements fréquents de cette cathode s'imposent. Enfin, la chambre intérieure n'est pas toujours facile à réaliser dans le graphite, surtout lorsque la cathode est de petite taille ou de forme sophistiquée.Since graphite is a porous material, it is unfortunately necessary to carry out a tedious operation of sealing the walls of the interior chamber of the cathode by means of impermeable resins. In addition, this sealing not being possible at the tapping, there are possibilities of leakage of cooling water at this level, which greatly limits the pressure that can be given to this water, and therefore its flow, and consequently cooling. On the other hand, the graphite cathode resists poorly over time, under the very severe conditions of temperature, acidity and voltage and electrical intensity to which it is subjected during the anodic oxidation. It follows that frequent changes to this cathode are necessary. Finally, the interior chamber is not always easy to produce in graphite, especially when the cathode is small or of sophisticated shape.

Le but de la présente invention est par conséquent de remédier aux inconvénients ci-dessus mentionnés et pour ce faire, elle propose un dispositif qui se caractérise en ce que la cathode est constituée par un tube en acier inoxydable comportant au moins deux branches, l'une au moins de ces branches étant maintenue localement par l'organe de préhension, et l'extrémité libre d'une ou plusieurs de ces branches étant raccordée à une alimentation en fluide de refroidissement, l'extrémité libre de la ou des branches restantes étant raccordée à une évacuation de fluide de refroidissement.The object of the present invention is therefore to remedy the drawbacks mentioned above and to do this, it provides a device which is characterized in that the cathode is constituted by a stainless steel tube comprising at least two branches, the at least one of these branches being held locally by the gripping member, and the free end of one or more of these branches being connected to a supply of cooling fluid, the free end of the remaining branch (s) being connected to a coolant outlet.

Non seulement, l'acier inoxydable résiste particulièrement bien aux conditions de fonctionnement requises pour l'oxydation anodique, mais encore il est possible de le conformer en tube dont le refroidissement par circulation interne d'un fluide de refroidissement est extrêmement efficace. En effet, dans l'oxydation anodique par électrolyse au tampon, il est indispensable pour obtenir un revêtement protecteur de bonne qualité et d'épaisseur suffisante, d'opérer à des températures aussi basses que possible, d'où la nécessité absolue d'évacuer les calories dégagées au niveau de la cathode du fait des intensités de courant très élevées appliquées à cette dernière.Not only does stainless steel resist particularly well to the operating conditions required for anodic oxidation, but it is also possible to conform it to a tube whose cooling by internal circulation of a cooling fluid is extremely effective. Indeed, in anodic oxidation by buffer electrolysis, it is essential to obtain a protective coating of good quality and of sufficient thickness, to operate at temperatures as low as possible, hence the absolute need to evacuate the calories released at the cathode due to the very high current intensities applied to the latter.

En outre, le tube en acier inoxydable ne posant aucun problème d'étanchéité, il est possible d'y faire circuler le fluide de refroidissement sous très forte pression et par conséquent avec un débit très élevé ce qui permet encore d'accentuer le refroidissement de la cathode.In addition, since the stainless steel tube poses no sealing problem, it is possible to circulate the cooling fluid therein under very high pressure and therefore with a very high flow rate, which further accentuates the cooling of the cathode.

Selon un mode de réalisation particulier, la liaison entre le tube formant cathode et le pôle négatif est assurée par l'intermédiaire d'une masse conductrice du courant électrique contenue dans l'organe de préhension, l'une au moins des branches du tube étant en contact avec cette masse conductrice.According to a particular embodiment, the connection between the cathode-forming tube and the negative pole is ensured by means of a conductive mass of the electric current contained in the gripping member, at least one of the branches of the tube being in contact with this conductive mass.

La cathode sera de préférence sensiblement en forme de U dont les deux branches sont maintenues dans l'organe de préhension au voisinage de leur extrémité libre.The cathode will preferably be substantially U-shaped, the two branches of which are held in the gripping member in the vicinity of their free end.

Le dispositif résultant est de ce fait compact, d'un maniement aisé et permet, en choisissant la longueur des branches du tube en U, de traiter des zones d'accès difficile, voire impossible, avec les dispositifs de l'art antérieur.The resulting device is therefore compact, easy to handle and makes it possible, by choosing the length of the branches of the U-shaped tube, to treat areas of difficult or even impossible access with the devices of the prior art.

Il est à noter que le fluide de refroidissement peut être constitué par l'électrolyte, la cathode étant percée, au voisinage de la partie en contact avec la masse absorbante, de fins orifices d'écoulement de l'électrolyte. De cette manière, il est possible d'assurer le refroidissement de la cathode et, simultanément, de maintenir la masse absorbante constamment imbibée en électrolyte, ce qui évite d'avoir recours, comme c'est le cas dans les dispositifs connus, à une rampe d'amenée en électrolyte extérieure et indépendante du dispositif d'anodisation lui-même, rampe qui est encombrante et rend difficiles les opérations d'anodisation.It should be noted that the cooling fluid can consist of the electrolyte, the cathode being pierced, in the vicinity of the part in contact with the absorbent mass, fine orifices for the flow of the electrolyte. In this way, it is possible to ensure the cooling of the cathode and, simultaneously, to maintain the absorbent mass constantly soaked in electrolyte, which avoids having to resort, as is the case in known devices, to a external electrolyte supply ramp independent of the anodizing device itself, ramp which is bulky and makes anodizing operations difficult.

Toutefois, le dispositif selon l'invention comportera de préférence une amenée en électrolyte disposée au voisinage de la cathode et de la masse absorbante, de manière à ce que cette dernière puisse absorber l'électrolyte qui s'écoule de cette amenée, cette dernière étant maintenue localement par l'organe de préhension. Dans ce cas, la cathode reste réfrigérée par le fluide de refroidissement qui la traverse et l'électrolyte provient d'une source autre que la cathode, source qui, lorsqu'elle est constituée par un tube en acier inoxydable fermé à l'une de ses extrémités, percé de fins orifices livrant passage à l'électrolyte, et maintenu dans l'organe de préhension au voisinage de son extrémité libre, est intimement incorporée au sein du dispositif d'anodisation et forme un tout compact avec ce dernier. Cette disposition présente l'avantage sur celle décrite ci-dessus, de permettre de régler à volonté la quantité d'électrolyte à déverser sur la masse absorbante, sans pour autant nuire au refroidissement de la cathode et sans pour autant augmenter l'encombrement du dispositif d'anodisation et compliquer sa structure et son maniement.However, the device according to the invention will preferably include an electrolyte supply disposed in the vicinity of the cathode and of the absorbent mass, so that the latter can absorb the electrolyte flowing from this supply, the latter being maintained locally by the gripping member. In this case, the cathode remains refrigerated by the cooling fluid which passes through it and the electrolyte comes from a source other than the cathode, a source which, when it is constituted by a stainless steel tube closed at one of its ends, pierced with fine orifices delivering passage to the electrolyte, and maintained in the gripping member in the vicinity of its free end, is intimately incorporated within the anodizing device and forms a compact whole with the latter. This arrangement has the advantage over that described above, of making it possible to regulate at will the quantity of electrolyte to be poured onto the absorbent mass, without however harming re cooling of the cathode and without increasing the size of the anodizing device and complicating its structure and handling.

Avantageusement, le tube d'amenée en électrolyte est disposé sensiblement dans le plan longitudinal de symétrie du tube en U. Ainsi, lorsque ce tube est situé entre les deux branches du tube en U, l'encombrement de l'ensemble cathode-tube d'amenée en électrolyte est minimum et en choisissant convenablement l'emplacement des orifices, il est possible de maintenir parfaitement imbibée en électrolyte la masse absorbante au niveau de la zone de travail de la cathode. Par ailleurs, lorsque le tube d'amenée en électrolyte est situé légèrement au-dessus du plan formé par les deux branches de la cathode en U, il est possible, toujours en choisissant la position des orifices pratiqués dans ce tube, de s'assurer que l'électrolyte qui s'écoule de ces orifices vienne se répandre sur l'une et/ou l'autre des branches de la cathode, contribuant ainsi au refroidissement de cette dernière.Advantageously, the electrolyte supply tube is disposed substantially in the longitudinal plane of symmetry of the U-shaped tube. Thus, when this tube is located between the two branches of the U-shaped tube, the size of the cathode-tube assembly d The supply of electrolyte is minimal and by choosing the location of the orifices suitably, it is possible to keep the absorbent mass perfectly imbibed in electrolyte at the working area of the cathode. Furthermore, when the electrolyte supply tube is located slightly above the plane formed by the two branches of the U-shaped cathode, it is possible, always by choosing the position of the orifices made in this tube, to ensure that the electrolyte flowing from these orifices spreads over one and / or the other of the branches of the cathode, thus contributing to the cooling of the latter.

Selon une variante, le tube d'amenée en électrolyte peut être en contact avec la masse conductrice du courant électrique et dans ce cas, il jouera également le rôle de cathode et pourra contribuer à l'oxydation anodique.According to a variant, the electrolyte supply tube may be in contact with the conductive mass of the electric current and in this case, it will also play the role of cathode and may contribute to anodic oxidation.

Avantageusement, la ou les branches de la cathode en contact avec la masse conductrice et éventuellement le tube d'amenée en électrolyte sont immobilisés respectivement dans des alésages prévus dans cette masse conductrice. Ce type d'assemblage permet non seulement un bon contact électrique, mais confère en outre une bonne rigidité au dispositif.Advantageously, the branch or branches of the cathode in contact with the conductive mass and possibly the electrolyte supply tube are immobilized respectively in bores provided in this conductive mass. This type of assembly not only allows good electrical contact, but also gives good rigidity to the device.

Selon un mode de réalisation préféré, la masse absorbante se présente sous la forme d'un manchon fermé à l'une de ses extrémités, s'adaptant sur tout ou partie de la portion de cathode et éventuellement du tube d'amenée en électrolyte, non maintenue dans l'organe de préhension.According to a preferred embodiment, the absorbent mass is in the form of a sleeve closed at one of its ends, fitting over all or part of the cathode portion and optionally of the electrolyte supply tube, not maintained in the gripping member.

L'ensemble cathode-tube d'amenée en électrolyte est ainsi entouré par la masse absorbante, ce qui évite que l'électrolyte dégoutte de manière intempestive et permet ainsi d'utiliser le dispositif d'anodisation dans n'importe quelle position.The cathode-tube assembly for supplying electrolyte is thus surrounded by the absorbent mass, which prevents the electrolyte from inadvertently dripping and thus allows the anodization device to be used in any position.

Les masses absorbantes connues à ce jour dans l'électrolyse au tampon sont essentiellement constituées par des mélanges nylon-coton. Toutefois, ces matériaux résistent très mal aux conditions requises pour l'oxydation anodique.The absorbent masses known to date in buffer electrolysis consist essentially of nylon-cotton blends. However, these materials resist very poorly the conditions required for anodic oxidation.

Aussi, la présente invention a-t-elle également pour objet un nouveau type de masse absorbante, utilisable notamment dans le dispositif d'anodisation décrit ci-dessus et ci-après. Plus précisément, cette masse absorbante est constituée par de la ouate de polyester enfermée dans une gaine faite de fibres de polypropylène ou de polyester tissées.Also, the present invention also relates to a new type of absorbent mass, usable in particular in the anodizing device described above and below. More specifically, this absorbent mass consists of polyester wadding enclosed in a sheath made of woven polypropylene or polyester fibers.

En particulier, ce polyester, sous forme de ouate ou de fibres tissées, est celui résultant de la copolymérisation de glycols et de diacides aromatiques divers, et de préférence, celui résultant de la copolymérisation du glycol et de l'acide téréphtalique.In particular, this polyester, in the form of wadding or woven fibers, is that resulting from the copolymerization of glycols and various aromatic diacids, and preferably that resulting from the copolymerization of glycol and terephthalic acid.

Le polypropylène utilisé pour réaliser la gaine sera de préférence un polymère de structure isotactique du type MERAKLON ".The polypropylene used to make the sheath will preferably be a polymer of isotactic structure of the MERAKLON type ".

Enfin, la présente invention a également pour objet de nouveaux électrolytes pour l'oxydation anodique par électrolyse au tampon, utilisables notamment dans le dispositif d'anodisation objet de la présente demande.Finally, the present invention also relates to new electrolytes for anodic oxidation by buffer electrolysis, usable in particular in the anodization device which is the subject of the present application.

Plus précisément, ces électrolytes sont constitués par une solution aqueuse d'acide sulfurique concentré, d'anhydride chromique, d'acide sulfamique et éventuellement de sulfate de magnésium. Ceux-ci sont particulièrement adaptés à l'oxydation anodique de l'aluminium.More specifically, these electrolytes consist of an aqueous solution of concentrated sulfuric acid, chromic anhydride, sulfamic acid and optionally magnesium sulfate. These are particularly suitable for the anodic oxidation of aluminum.

Ils peuvent en outre contenir du sulfate de magnésium et sont alors notamment adaptés à l'oxydation anodique des alliages d'aluminium légers.They can also contain magnesium sulphate and are therefore particularly suitable for the anodic oxidation of light aluminum alloys.

Ces nouveaux électrolytes permettent l'obtention de couches d'oxyde présentant une meilleure qualité que celles obtenues avec les électrolytes connus, en particulier sur le plan de la résistance aux agents chimiques, de la résistance à la corrosion marine, de la dureté, de la résistance à l'abrasion et de l'épaisseur.These new electrolytes make it possible to obtain oxide layers having a better quality than those obtained with known electrolytes, in particular in terms of resistance to chemical agents, resistance to marine corrosion, hardness, abrasion resistance and thickness.

Un mode d'exécution du dispositif selon la présente invention est représenté à titre d'exemple sur le dessin annexé dans lequel:

  • - la figure 1 est une vue en élévation et en coupe transversale d'un mode de réalisation du dispositif selon l'invention, et
  • - la figure 2 est une vue en coupe selon la ligne II-II du dispositif de la figure 1.
An embodiment of the device according to the present invention is shown by way of example in the appended drawing in which:
  • FIG. 1 is a view in elevation and in cross section of an embodiment of the device according to the invention, and
  • - Figure 2 is a sectional view along line II-II of the device of Figure 1.

Le dispositif objet de ces figures comprend un bloc 1 en matière plastique, de forme sensiblement tronconique, muni d'un manche 2, la fixation de ce dernier sur le bloc 1 étant assurée, par exemple, par simple vissage d'une tige filetée (non représentée) portée par le manche, dans un taraudage (non représenté) pratiqué dans ledit bloc. La petite base 3 du bloc tronconique 1 présente une ouverture 4 qui se prolonge en une chambre intérieure dans laquelle est logée à force une masse conductrice cylindrique 5, de préférence en acier inoxydable, et dont l'axe est confondu avec l'axe du bloc tronconique 1. Cette masse 5 est pourvue de trois alésages (6, 7, 8) situés respectivement dans le prolongement d'alésages de même section (6a, 7a, 8a) réalisés dans le bloc 1.The device which is the subject of these figures comprises a block 1 of plastic material, of substantially frustoconical shape, provided with a handle 2, the fixing of the latter to the block 1 being ensured, for example, by simply screwing in a threaded rod ( not shown) carried by the handle, in a thread (not shown) formed in said block. The small base 3 of the frustoconical block 1 has an opening 4 which extends into an interior chamber in which is housed by force a cylindrical conductive mass 5, preferably made of stainless steel, and the axis of which coincides with the axis of the block frustoconical 1. This mass 5 is provided with three bores (6, 7, 8) situated respectively in the extension of bores of the same section (6a, 7a, 8a) produced in block 1.

Dans l'exemple de réalisation représenté, deux des trois couples d'alésages complémentaires (6, 6a) et (7, 7a) sont sensiblement dans le plan horizontal de symétrie du bloc 1, de part et d'autre et à égale distance du plan vertical de symétrie de ce même bloc 1, alors que le troisième couple d'alésages complémentaires (8, 8a) est situé sensiblement dans ce plan vertical de symétrie, sous les deux couples d'alésages (6, 6a) et (7, 7a). La position dans le bloc 1 décrite ci-dessus de ces différents alésages est la plus rationnelle, mais pourrait être toute autre sans que cela ne modifie en rien l'esprit de l'invention. Par exemple, les couples d'alésages (6, 6a) et (7, 7a) pourraient être dans un plan différent du plan horizontal de symétrie et/ou dans deux plans distincts. De même, le couple d'alésages (8, 8a) pourrait être en dehors du plan vertical de symétrie et/ou au-dessus des couples d'alésages (6, 6a) et (7, 7a).In the embodiment shown, two of the three pairs of complementary bores (6, 6a) and (7, 7a) are substantially in the horizontal plane of symmetry of the block 1, on either side and at equal distance from the vertical plane of symmetry of this same block 1, while the third pair of complementary bores (8, 8a) is situated substantially in this vertical plane of symmetry, under the two pairs of bores (6, 6a) and (7, 7a). The position in block 1 described above of these different bores is the most rational, but could be any other without this in any way modifying the spirit of the invention. For example, the pairs of bores (6, 6a) and (7, 7a) could be in a plane different from the horizontal plane of symmetry and / or in two separate planes. Similarly, the pair of bores (8, 8a) could be outside the vertical plane of symmetry and / or above the pairs of bores (6, 6a) and (7, 7a).

Par ailleurs, au niveau de la partie située au-dessus du plan horizontal de symétrie du bloc 1, la masse 5 se prolonge, par une saillie 9, vers la grande base 10 du bloc tronconique 1 sans toutefois atteindre cette base. Cette saillie 9 est pourvue d'un taraudage 11 perpendiculaire à la base 10 et situé dans le prolongement d'un alésage 12 de même section réalisé dans le bloc 1 et partant de ladite base 10, taraudage qui reçoit la tige filetée 13 d'une fiche de raccordement électrique 14 apte à être relié au pôle négatif d'une source électrique (non représentée). Bien entendu, la position de la saillie 9 et le mode de fixation de la fiche 14 sur cette saillie pourraient être toute autre sans que cela ne modifie en rien le fonctionnement du dispositif d'anodisation.Furthermore, at the level of the part situated above the horizontal plane of symmetry of the block 1, the mass 5 is extended, by a projection 9, towards the large base 10 of the frustoconical block 1 without however reaching this base. This projection 9 is provided with a thread 11 perpendicular to the base 10 and located in the extension of a bore 12 of the same section made in the block 1 and starting from said base 10, thread which receives the threaded rod 13 of a electrical connection plug 14 capable of being connected to the negative pole of an electrical source (not shown). Of course, the position of the projection 9 and the method of fixing the plug 14 on this projection could be any other without this in any way modifying the operation of the anodizing device.

Dans les couples d'alésage (6, 6a) et (7, 7a) sont enfoncées à force et de manière à traverser de part en part le bloc 1, respectivement les deux branches (15,16) d'un tube en U 17 en acier inoxydable, qui sont chacune contre-coudées légèrement en avant de la base 3, les parties contre-coudées (18, 19) étant faiblement inclinées l'une vers l'autre, et se prolongeant respectivement par deux tronçons horizontaux (20, 21) se raccordant au fond du U et situés dans le même plan lui-même situé au-dessous du bloc 1.In the pairs of bores (6, 6a) and (7, 7a) are forced in and so as to pass right through the block 1, respectively the two branches (15,16) of a U-shaped tube 17 made of stainless steel, which are each bent slightly in front of the base 3, the bent parts (18, 19) being slightly inclined towards each other, and extending respectively by two horizontal sections (20, 21) connecting to the bottom of the U and located in the same plane itself located below block 1.

L'extrémité libre du tube 15 émergeant de la base 10 est destinée à être reliée à une arrivée (non représentée) en fluide de refroidissement, par exemple de l'eau, l'extrémité libre du tube 16 émergeant elle-aussi de la base 10 étant, quant à elle, destinée à être reliée à une évacuation (non représentée) en fluide de refroidissement.The free end of the tube 15 emerging from the base 10 is intended to be connected to an inlet (not shown) in cooling fluid, for example water, the free end of the tube 16 also emerging from the base 10 being, in turn, intended to be connected to an outlet (not shown) in cooling fluid.

Dans le couple d'alésage (8, 8a) est également enfoncé à force et de manière à traverser de part en part le bloc 1, un tube 22 en acier inoxydable lui aussi contre-coudé, la partie contre-coudée 23 se prolongeant par un tronçon horizontal 24 fermé à son extrémité et situé juste au-dessus du plan formé par les tronçons (20, 21), ce tronçon 24 étant pourvu de deux rangées de fins orifices (25, 26) en regard chacune respectivement avec lesdits tronçons (20, 21). L'extrémité libre du tube 22, c'est-à-dire celle émergeant de la base 10 est pour sa part destinée à être reliée à une arrivée en électrolyte.In the bore torque (8, 8a) is also forced in and so as to pass right through the block 1, a tube 22 of stainless steel also bent, the bent part 23 extending by a horizontal section 24 closed at its end and located just above the plane formed by the sections (20, 21), this section 24 being provided with two rows of fine orifices (25, 26) each facing each other respectively with said sections ( 20, 21). The free end of the tube 22, that is to say that emerging from the base 10 is for its part intended to be connected to an electrolyte supply.

Enfin, un manchon 27 sensiblement cylindrique et fermé à l'une de ses extrémités est enfilé sur les tronçons (20, 21, 24) qui sont de ce fait totalement entourés par ce manchon. Ce dernier est constitué par de la ouate de polyester 28 enfermée dans une gaine 29 faite de fibres tissées en polypropylène MERAKLON. Il va de soi que la forme de ce manchon n'est pas limitée à la forme cylindrique, mais dépendra en fait de la forme de la cathode. Dans le mode de réalisation décrit, cette cathode est en forme de U, mais elle pourrait être différente et adaptée à la géométrie de la surface à anodiser.Finally, a sleeve 27 substantially cylindrical and closed at one of its ends is threaded on the sections (20, 21, 24) which are therefore totally surrounded by this sleeve. The latter consists of polyester wadding 28 enclosed in a sheath 29 made of woven fibers of polypropylene MERAKLON. It goes without saying that the shape of this sleeve is not limited to the cylindrical shape, but will in fact depend on the shape of the cathode. In the embodiment described, this cathode is U-shaped, but it could be different and adapted to the geometry of the surface to be anodized.

Le fonctionnement du dispositif ci-dessus décrit est le suivant. On raccorde les extrémités des branches (15, 16) respectivement à une arrivée et à une évacuation en fluide de refroidissement, fluide dont la circulation est par exemple assurée par une pompe. De même, on raccorde l'extrémité du tube 22 à une arrivée en électrolyte elle-même en relation avec une pompe d'alimentation en électrolyte, dont le débit est réglable. Enfin, on raccorde la fiche 14 au pôle négatif d'un générateur de courant approprié, la pièce à anodiser étant raccordée au pôle positif de ce même générateur.The operation of the device described above is as follows. The ends of the branches (15, 16) are connected respectively to an inlet and to an outlet for cooling fluid, fluid whose circulation is for example ensured by a pump. Likewise, the end of the tube 22 is connected to an electrolyte supply, itself connected to an electrolyte supply pump, the flow rate of which is adjustable. Finally, plug 14 is connected to the negative pole of an appropriate current generator, the part to be anodized being connected to the positive pole of this same generator.

Le générateur peut être de quelque type que ce soit, par exemple à courant continu ou à courant pulsé.The generator can be of any type, for example direct current or pulsed current.

Ces différents raccordements une fois effectués et le manchon 27 bien imbibé d'électrolyte, on procède à l'anodisation proprement dite en déplaçant ce manchon sur la surface à traiter tout en surveillant l'alimentation en électrolyte pour pallier l'évaporation et s'assurer que le manchon reste toujours parfaitement alimenté en électrolyte.Once these various connections have been made and the sleeve 27 is well soaked with electrolyte, the actual anodization is carried out by moving this sleeve over the surface to be treated while monitoring the supply of electrolyte to compensate for evaporation and ensure that the sleeve always remains perfectly supplied with electrolyte.

La qualité de la couche d'oxyde formée étant d'autant meilleure que l'anodisation est faite à plus basse température, l'électrode sera réfrigérée au maximum et l'électrolyte utilisé sera à la température la plus basse possible, et de préférence à une température égale ou inférieure à 20°C.The quality of the oxide layer formed being all the better as the anodization is carried out at a lower temperature, the electrode will be refrigerated to the maximum and the electrolyte used will be at the lowest possible temperature, and preferably at a temperature equal to or lower than 20 ° C.

Les tensions de fonctionnement du dispositif selon l'invention seront en général de l'ordre de 25 à 50 Volts, valeurs auxquelles le rendement de l'anodisation sera sensiblement constant, les densités de courant pouvant varier entre 15 et 250 A/ dm2.The operating voltages of the device according to the invention will generally be of the order of 25 to 50 volts, values at which the efficiency of the anodization will be substantially constant, the current densities possibly varying between 15 and 250 A / d m2 .

La pièce à anodiser peut être constituée par tout métal susceptible de subir l'oxydation anodique, tel que par exemple l'aluminium et ses alliages légers, ainsi que le titane et ses alliages. Les électrolytes à mettre en oeuvre dans le dispositif selon l'invention seront bien entendu fonction de la nature du métal constituant cette pièce.The part to be anodized may consist of any metal capable of undergoing anodic oxidation, such as for example aluminum and its light alloys, as well as titanium and its alloys. The electrolytes to be used in the device according to the invention will of course depend on the nature of the metal constituting this part.

Quand ce métal est l'aluminium, l'électrolyte sera de préférence constitué par une solution aqueuse contenant 30 à 100 g/l, et plus particulièrement environ 35 g/l, d'acide sulfamique; 10 à 60 g/l, et plus particulièrement environ 17 g/l, d'anhydride chromique; et 9 à 55 g/l, et plus particulièrement environ 13 g/l, d'acide sulfurique concentré.When this metal is aluminum, the electrolyte will preferably consist of an aqueous solution containing 30 to 100 g / l, and more particularly approximately 35 g / l, of sulfamic acid; 10 to 60 g / l, and more particularly approximately 17 g / l, of chromic anhydride; and 9 to 55 g / l, and more particularly approximately 13 g / l, of concentrated sulfuric acid.

Enfin, quand ce métal est un alliage léger d'aluminium, comme les alliages d'A-U4G, l'électrolyte sera de préférence constitué par une solution aqueuse contenant 30 à 100 g/l, et plus particulièrement environ 100 g/l, d'acide sulfamique; 10 à 60 g/l, et plus particulièrement environ 48 g/l, d'anhydride chromique; 9 à 55 g/l, et plus particulièrement environ 37 g/l, d'acide sulfurique concentré; et environ 100 g/l de sulfate de magnésium heptahydraté.Finally, when this metal is a light aluminum alloy, like the A-U4G alloys, the electrolyte will preferably consist of an aqueous solution containing 30 to 100 g / l, and more particularly about 100 g / l, sulfamic acid; 10 to 60 g / l, and more particularly approximately 48 g / l, of chromic anhydride; 9 to 55 g / l, and more particularly approximately 37 g / l, of concentrated sulfuric acid; and about 100 g / l of magnesium sulfate heptahydrate.

Claims (18)

1. A device for anodic oxidation by pad electrolysis in which the electrolyte is retained within an absorbant mass (27) contacting a cathode which comprises an inner cooling circuit, the cathode being connected to the negative pole of an electric power supply and supported on an electrically insulated gripping means (1, 2), characterized in that the cathode consists of a stainless steel tube (17) having at least two legs (15, 16), at least one of which is held locally by said gripping means (1, 2) the free end of one or more legs (15) being connected to a cooling fluid supply, the end of the remaining leg or legs (16) being connected to a cooling fluid outlet.
2. A device according to claim 1, characterized in that the connection between the cathode tube (17) and the negative pole is provided by an electrically conductive mass (5, 9) contained within the gripping means (1, 2) at least one of the legs (15, 16) of the tube (17) being in contact with this conductive mass.
3. A device according to claim 1 or 2, characterized in that the cathode is substantially U-shaped, both legs (15, 16) of the U being secured in the gripping means (1, 2) adjacent to their free end.
4. A device according to claim 1, 2 or 3, characterized in that the electrolyte acts as a cooling fluid, the cathode being provided with small orifices for electrolyte flow adjacent to the portion (20, 21) contacting the absorbent mass (27).
5. A device according to claim 1, 2, 3 or 4, characterized in that it further includes an electrolyte feed inlet (22), adjacent to the cathode (17) and the absorbent mass (27), so that the latter is able to absorb the electrolyte flowing from the feed inlet which is locally held by the gripping means (1, 2).
6. A device according to claim 5, in which the electrolyte feed inlet (22) consists of a stainless steel tube closed at one end, said tube being provided with small orifices (25, 26), allowing a passage for the electrolyte, and being held in the gripping means (1, 2) adjacent to its free end.
7. A device according to claim 5 or 6, characterized in that the electrolyte feed tube (22) is arranged substantially in the longitudinal plane of symmetry of the U-shaped tube (17).
8. A device according to claim 5, 6 or 7, characterized in that the electrolyte feed tube (22) contacts the electrically conductive mass (5, 9).
9. A device according to any one of claims 2 to 8, characterized in that the leg or legs (15, 16) of the cathode (17), which is or are in contact with the conductive mass (5, 9) if applicable, with the electrolyte feed tube (22), is or are, firmly secured in bores (6, 7) provided in said conductive mass.
10. A device according to any one of the preceding claims, characterized in that the absorbent mass (27) is in the form of a sleeve closed at one end, which fits over all or part of the portion (20, 21, 24) of the cathode and, if applicable, of the electrolyte feed tube, which is or are not held in the gripping means (1, 2).
11. A device according to any one of the preceding claims characterized in that said absorbent mass consists of a polyester wadding (28) enclosed in a sheath (29) of woven polypropylene or polyester fibers.
12. A device according to claim 11, characterized in that said polyester, in the form of a wadding or woven fibers, is a copolymer of a glycol and an aromatic diacid.
13. A device according to claim 11, characterized in that said polyester is poly(glycol terephthalate).
14. A device according to claim 11, 12 or 13, characterized in that said polypropylene is of isotactic structure, preferably MERAKLON.
15. An electrolyte for use in the device according to any on of claims 1, 2, 3 and 5 to 14, characterized in that it consists of an aqueous solution of concentrated sulfuric acid, chromic anhydride, sulfamic acid and optionally magnesium sulfate.
16. An electrolyte according to claim 15, characterized in that it contains, per liter of aqueous solution, about 13 g of concentrated sulfuric acid, about 17 g of chromic anhydride and about 35 g of sulfamic acid.
17. An electrolyte according to claim 15, characterized in that it contains magnesium sulfate.
18. An electrolyte according to claim 17, characterized in that it contains, per liter of aqueous solution, about 37 g of concentrated sulfuric acid, about 48 g of chromic anhydride, about 100 g of sulfamic acid and about 100 g of magnesium sulfate heptahydrate.
EP81401459A 1980-09-22 1981-09-18 Apparatus for anodic oxydation by the pad-plating process, and electrolyte used therefor Expired EP0049192B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81401459T ATE27191T1 (en) 1980-09-22 1981-09-18 DEVICE FOR ANODIC OXIDATION ACCORDING TO THE PAD PROCESS AND ELECTROLYTE USED FOR THEREOF.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8020341 1980-09-22
FR8020341A FR2490685A1 (en) 1980-09-22 1980-09-22 IMPROVED DEVICE FOR ANODIC OXIDATION BY BUFFER ELECTROLYSIS AND ELECTROLYTES THEREFOR

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EP0049192A1 EP0049192A1 (en) 1982-04-07
EP0049192B1 true EP0049192B1 (en) 1987-05-13

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JP (1) JPS57114699A (en)
AR (1) AR224587A1 (en)
AT (1) ATE27191T1 (en)
AU (1) AU7552181A (en)
BR (1) BR8106139A (en)
CA (1) CA1188652A (en)
DE (1) DE3176188D1 (en)
DK (1) DK418081A (en)
ES (1) ES505636A0 (en)
FR (1) FR2490685A1 (en)
NO (1) NO156173C (en)
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DE3507927A1 (en) * 1985-03-06 1986-09-11 Dr.Ing.H.C. F. Porsche Ag, 7000 Stuttgart METHOD AND HAND DEVICE FOR SEMI-MECHANICAL GALVANIZING OF SHEET SURFACES
GB2336161B (en) 1998-04-06 2003-03-26 John Michael Lowe Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
US6939447B2 (en) 1998-04-06 2005-09-06 Tdao Limited Method of providing conductive tracks on a printed circuit and apparatus for use in carrying out the method
CN102492975A (en) * 2011-12-30 2012-06-13 中国科学院力学研究所 Apparatus for growing ceramic coating by electrolyte injection discharge and method thereof
CN103184498B (en) * 2013-03-08 2015-08-26 华南理工大学 Roller brush type differential arc oxidation treatment method and device
GB2535805A (en) * 2015-02-27 2016-08-31 Biomet Uk Healthcare Ltd Apparatus and method for selectively treating a surface of a component
US11686012B2 (en) * 2017-10-26 2023-06-27 Unison Industries, Llc Mandrel for electroforming
EP4194590A1 (en) * 2021-12-09 2023-06-14 Aalberts Surface Technologies GmbH Method and composition for selective anodisation

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US3349014A (en) * 1964-08-28 1967-10-24 Mc Donnell Douglas Corp Method and composition for the treatment of an aluminum surface

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BR8106139A (en) 1982-06-15
NO813204L (en) 1982-03-23
ES8300355A1 (en) 1982-11-01
NO156173C (en) 1987-08-12
EP0049192A1 (en) 1982-04-07
CA1188652A (en) 1985-06-11
ES505636A0 (en) 1982-11-01
JPH026839B2 (en) 1990-02-14
ATE27191T1 (en) 1987-05-15
AR224587A1 (en) 1981-12-15
FR2490685A1 (en) 1982-03-26
AU7552181A (en) 1982-04-01
NO156173B (en) 1987-04-27
FR2490685B1 (en) 1984-06-22
DE3176188D1 (en) 1987-06-19
PT73714A (en) 1981-10-01
NZ198430A (en) 1985-03-20
DK418081A (en) 1982-03-23
PT73714B (en) 1982-12-30
JPS57114699A (en) 1982-07-16

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