EP0624206B1 - High-hardness conductive material and method for manufacturing same - Google Patents

High-hardness conductive material and method for manufacturing same Download PDF

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Publication number
EP0624206B1
EP0624206B1 EP93904133A EP93904133A EP0624206B1 EP 0624206 B1 EP0624206 B1 EP 0624206B1 EP 93904133 A EP93904133 A EP 93904133A EP 93904133 A EP93904133 A EP 93904133A EP 0624206 B1 EP0624206 B1 EP 0624206B1
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Prior art keywords
conductive material
material according
oxide
hardness conductive
alloy
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German (de)
French (fr)
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EP0624206A1 (en
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Christian Bataillon
Solange Brunet
Odette Sanatine
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/08Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/10Oxidising

Definitions

  • the present invention relates to a conductive material of high hardness and its manufacturing process.
  • connection elements or the relay contacts In the field of electrical contacts used in connectors, in mobile relays, etc., we have long sought to make contacts which, owing to their hardness, are capable of operating for a very long time even under difficult conditions.
  • the materials used to make these connection elements or the relay contacts must have very good physical and chemical unalterability properties, great hardness and of course good electronic conductivity properties.
  • the object of the invention is to remedy these drawbacks and to produce a material of high hardness, of great chemical inertness and of good electronic conductivity, which can be used for example as an electrical contact.
  • the invention relates to a conductive material of high hardness.
  • this material consists of an alloy comprising a first oxide of a metal, this first insulating and unalterable oxide forming the matrix of the material and a second oxide of an addition element forming a conductor electronic, the various islands constituting this second oxide being interconnected to form a conductive path inside said matrix.
  • the metal is chosen from the elements of groups IVb or Vb of the periodic table, for example titanium, zirconium or niobium.
  • the addition element is chosen from the elements of groups Ib, IIb, IIIa or IVa of the periodic table, for example copper, silver, mercury, indium or tin.
  • the oxidation stage makes it possible, on the one hand, to make the base metal unalterable and, on the other hand, to form precipitates or islets which conduct the addition element oxide inside the oxide. base metal. Then, the physical percolation treatment makes it possible to interconnect the conductive islands produced by oxidation and thus ensure the electronic conductivity of the material obtained.
  • the oxidation of the alloy is carried out either by anodization when the alloy is in the form of a thin film, with a thickness of less than 0.5 ⁇ m, or by the action of a gaseous oxidant. , liquid or dissolved, at a temperature close to 400 ° C, when the alloy is in the form of a thick film.
  • the physical percolation treatment is carried out by a heat treatment at a temperature below the phase transition temperature of the alloy considered.
  • the material according to the invention is an alloy comprising a first oxide of a metal, this first insulating and unalterable oxide forming the matrix of the material and a second oxide of an addition element forming an electronic conductor, the various islands constituting this second oxide being interconnected to form a conductive path inside said matrix.
  • the metal whose oxide is insulating but which resists physical attacks relatively well and chemical is chosen from the elements of groups IVb or Vb of the periodic table.
  • titanium, zirconium and niobium are preferred but nonlimiting examples.
  • the addition element is chosen from the metals of groups lb, IIb, IIIa or IVa of the periodic table.
  • these metals copper, silver, mercury, indium and tin are particularly well suited. However, these are not the only conductive oxides that can be used.
  • the zirconium couple associated with a small percentage of tin gives good results.
  • the maximum concentration of additive element corresponds to the limit of solubility in the metal matrix. Not all of these solubility limits are known, however, those of tin in zirconium are known. This is 17 atomic%.
  • the minimum concentration of addition elements in the alloy is that corresponding to the proportion sufficient for a percolation phenomenon to occur later in the final step. This concentration is approximately 0.1 atomic%.
  • This method comprises a first step consisting in taking or preparing an alloy comprising a metal whose oxide is unalterable and insulating and an addition element whose oxide is an electronic conductor with the metals and elements previously described.
  • the next step in the process according to the invention consists in subjecting this alloy to oxidation.
  • This oxidation makes the base metal unalterable since already oxidized and creates conductive precipitates in the oxide matrix.
  • the oxidation can be carried out, for example, by anodization, by dry oxidation or by the action of a gaseous, liquid or dissolved oxidant, the latter possibly being water or water vapor.
  • Oxidation can be carried out either in massive form, or in the form of a coating deposited directly on a metal part in order to give it the desired properties of inalterability and electronic conductivity.
  • the implementation of the method according to the invention must meet two main objectives, on the one hand, to allow the rapid production of films of conductive material of high hardness and on the other hand, to obtain compact films, that is to say - say without mechanical defects such as pores or cracks.
  • the faster an oxidation and the less compact the film obtained It is therefore necessary to find a compromise between the mechanical quality of the film and its speed of manufacture.
  • anodization is the most suitable oxidation mode.
  • oxidation in water vapor at around 400 ° C. gives very good results, with a speed oxidation of 1 to 2 ⁇ m per week.
  • the third step of the manufacturing process according to the invention consists in subjecting the oxidized alloy to physical treatment in order to create, by a percolation phenomenon, conductive paths interconnected in the insulating oxide layer.
  • Percolation is a physical phenomenon that allows certain transfers to take place in a solid. When this percolation treatment is carried out, the electric charges can pass by following particular paths within the non-conductive oxide.
  • the percolation treatment is described for example in a book entitled "Introduction to percolation theory", (Introduction to the theory of percolation), Stauffer D., Aharony A., London: Taylor and Francis, 1992.
  • the oxidation step made it possible to produce precipitates or islets of conductive oxide which are linked together by this percolation treatment.
  • This percolation treatment is generally carried out by a heat treatment. Its role is to create the necessary connections, if the nature and concentration of the constituents allow it. The concentration ranges have been given beforehand.
  • the structure of the alloy must remain the same as at normal temperature of use. It is therefore necessary to operate at a temperature lower than that where a phase change begins to occur (phase transition temperature). This temperature naturally depends on the material considered.
  • This physical treatment can be carried out by a global heat treatment or on the contrary by a local heat treatment, intended to make conductive only a limited surface of the part considered. In the latter case, only part of the part is conductive and one can benefit from the insulating properties on the rest of the surface thereof.
  • Zirconium and tin alloys known under the trade name ZIRCALOY 2 and ZIRCALOY 4 were oxidized at 400 ° C in water vapor, placing them in an autoclave suitable for this type of operation. The oxidation lasted 1 to 2 weeks depending on the thickness desired for the oxide film. Then, the oxidized material was placed in an oven under primary vacuum, then heated for 1 to 2 hours at a temperature between 400 and 600 ° C to make the oxide layer conductive. Then, the material was rapidly cooled by introducing an inert gas such as argon or helium into the furnace.
  • an inert gas such as argon or helium

Abstract

A material having superior electronic conductivity and physical and chemical stability properties. The material consists of an alloy including a first insulating and incorruptible metal oxide forming the metal matrix of the material, and a second oxide of an alloying element acting as an electronic conductor. The various precipitates making up the second oxide are mutually connected to form a conductive path within said matrix. Said material may be used particularly to produce electrical contacts.

Description

La présente invention concerne un matériau conducteur de haute dureté et son procédé de fabrication.The present invention relates to a conductive material of high hardness and its manufacturing process.

Dans le domaine des contacts électriques utilisés en connectique, dans les relais mobiles, etc., on a longtemps cherché à réaliser des contacts susceptibles grâce à leur dureté, de fonctionner très longtemps même dans des conditions difficiles. Les matériaux utilisés pour réaliser ces éléments de connectique ou les contacts des relais doivent présenter de très bonnes propriétés d'inaltérabilité physique et chimique, une grande dureté et bien entendu de bonnes propriétés de conductibilité électronique.In the field of electrical contacts used in connectors, in mobile relays, etc., we have long sought to make contacts which, owing to their hardness, are capable of operating for a very long time even under difficult conditions. The materials used to make these connection elements or the relay contacts must have very good physical and chemical unalterability properties, great hardness and of course good electronic conductivity properties.

Dans l'art antérieur, on assurait la bonne conductibilité au niveau des contacts en utilisant de l'or ou un matériau dont l'oxyde est conducteur tel que le cuivre, le bronze ou le béryllium. Toutefois, cette solution n'assure pas une grande durabilité des contacts. Lorsque ceux-ci sont utilisés dans des environnements difficiles, par exemple à température élevée, ou dans une atmosphère oxydante, ou lorsqu'ils sont soumis à des frottements intensifs, ils s'usent et se détériorent très rapidement. Inversement, on a également cherché à utiliser un matériau inaltérable car déjà oxydé tel qu'un oxyde réfractaire, mais on s'est heurté au caractère isolant de ce type de matériau.In the prior art, good conductivity at the contacts was ensured by using gold or a material whose oxide is conductive such as copper, bronze or beryllium. However, this solution does not ensure great durability of the contacts. When these are used in harsh environments, for example at high temperature, or in an oxidizing atmosphere, or when subjected to intensive friction, they wear and deteriorate very quickly. Conversely, attempts have also been made to use an unalterable material since it is already oxidized such as a refractory oxide, but we have come up against the insulating nature of this type of material.

En conséquence, l'invention a pour but de remédier à ces inconvénients et de réaliser un matériau de haute dureté, de grande inertie chimique et de bonne conductibilité électronique, qui puisse être utilisé par exemple comme contact électrique.Consequently, the object of the invention is to remedy these drawbacks and to produce a material of high hardness, of great chemical inertness and of good electronic conductivity, which can be used for example as an electrical contact.

A cet effet, l'invention concerne un matériau conducteur de haute dureté. Selon les caractéristiques de l'invention, ce matériau est constitué d'un alliage comprenant un premier oxyde d'un métal, ce premier oxyde isolant et inaltérable formant la matrice du matériau et un second oxyde d'un élément d'addition formant un conducteur électronique, les différents îlots constituant ce second oxyde étant reliés entre eux pour former un chemin conducteur à l'intérieur de ladite matrice.To this end, the invention relates to a conductive material of high hardness. According to the characteristics of the invention, this material consists of an alloy comprising a first oxide of a metal, this first insulating and unalterable oxide forming the matrix of the material and a second oxide of an addition element forming a conductor electronic, the various islands constituting this second oxide being interconnected to form a conductive path inside said matrix.

De façon avantageuse, le métal est choisi parmi les éléments des groupes IVb ou Vb de la classification périodique, par exemple le titane, le zirconium ou le niobium. De même, l'élément d'addition est choisi parmi les éléments des groupes Ib, IIb, IIIa ou IVa de la classification périodique, par exemple le cuivre, l'argent, le mercure, l'indium ou l'étain.Advantageously, the metal is chosen from the elements of groups IVb or Vb of the periodic table, for example titanium, zirconium or niobium. Likewise, the addition element is chosen from the elements of groups Ib, IIb, IIIa or IVa of the periodic table, for example copper, silver, mercury, indium or tin.

Ainsi, on utilise un métal fortement inaltérable, physiquement et chimiquement stable, résistant à des environnements difficiles à l'intérieur duquel l'élément d'addition assure la conductibilité électronique et permet la réalisation de contacts électriques.Thus, a highly unalterable metal is used, physically and chemically stable, resistant to harsh environments inside which the addition element provides electronic conductivity and allows the production of electrical contacts.

L'invention concerne également un procédé de fabrication du matériau qui vient d'être décrit. Selon les caractéristiques de l'invention, ce procédé comprend les étapes consistant à :

  • prendre un alliage comprenant un métal dont l'oxyde est inaltérable et isolant et un élément d'addition dont l'oxyde est un conducteur électronique,
  • oxyder cet alliage, et
  • faire subir un traitement physique à cet alliage oxydé de façon à créer par un phénomène de percolation, des chemins conducteurs interconnectés dans la couche d'oxyde isolante.
The invention also relates to a method of manufacturing the material which has just been described. According to the characteristics of the invention, this method comprises the steps consisting in:
  • take an alloy comprising a metal whose oxide is unalterable and insulating and an addition element whose oxide is an electronic conductor,
  • oxidize this alloy, and
  • subject this oxidized alloy to physical treatment so as to create by a phenomenon of percolation, conductive paths interconnected in the insulating oxide layer.

L'étape d'oxydation permet d'une part, de rendre le métal de base inaltérable et d'autre part, de former des précipités ou îlots conducteurs de l'oxyde d'élément d'addition à l'intérieur de l'oxyde du métal de base. Ensuite, le traitement physique de percolation permet d'interconnecter les îlots conducteurs réalisés par l'oxydation et d'assurer ainsi la conductibilité électronique du matériau obtenu.The oxidation stage makes it possible, on the one hand, to make the base metal unalterable and, on the other hand, to form precipitates or islets which conduct the addition element oxide inside the oxide. base metal. Then, the physical percolation treatment makes it possible to interconnect the conductive islands produced by oxidation and thus ensure the electronic conductivity of the material obtained.

De façon avantageuse, l'oxydation de l'alliage est réalisée soit par anodisation lorsque l'alliage est sous forme d'un film mince, d'une épaisseur inférieure à 0,5 µm, soit par l'action d'un oxydant gazeux, liquide ou dissous, à une température voisine de 400°C, lorsque l'alliage est sous forme d'un film épais.Advantageously, the oxidation of the alloy is carried out either by anodization when the alloy is in the form of a thin film, with a thickness of less than 0.5 μm, or by the action of a gaseous oxidant. , liquid or dissolved, at a temperature close to 400 ° C, when the alloy is in the form of a thick film.

De préférence, le traitement physique de percolation est réalisé par un traitement thermique à une température inférieure à la température de transition de phase de l'alliage considéré.Preferably, the physical percolation treatment is carried out by a heat treatment at a temperature below the phase transition temperature of the alloy considered.

L'invention sera mieux comprise à la lecture de la description suivante d'un mode de réalisation de l'invention donné à titre d'exemple illustratif et non limitatif.The invention will be better understood on reading the following description of an embodiment of the invention given by way of illustrative and nonlimiting example.

Le matériau selon l'invention est un alliage comprenant un premier oxyde d'un métal, ce premier oxyde isolant et inaltérable formant la matrice du matériau et un second oxyde d'un élément d'addition formant un conducteur électronique, les différents îlots constituant ce second oxyde étant reliés entre eux pour former un chemin conducteur à l'intérieur de ladite matrice.The material according to the invention is an alloy comprising a first oxide of a metal, this first insulating and unalterable oxide forming the matrix of the material and a second oxide of an addition element forming an electronic conductor, the various islands constituting this second oxide being interconnected to form a conductive path inside said matrix.

Le métal dont l'oxyde est isolant mais qui résiste relativement bien aux agressions physiques et chimiques est choisi parmi les éléments des groupes IVb ou Vb de la classification périodique des éléments. Parmi ces éléments, le titane, le zirconium et le niobium sont des exemples préférés mais non limitatifs.The metal whose oxide is insulating but which resists physical attacks relatively well and chemical is chosen from the elements of groups IVb or Vb of the periodic table. Among these elements, titanium, zirconium and niobium are preferred but nonlimiting examples.

L'élément d'addition dont l'oxyde est moins résistant mais possède une bonne conductibilité électronique, est choisi parmi les métaux des groupes lb, IIb, IIIa ou IVa de la classification périodique des éléments. Parmi ces métaux, le cuivre, l'argent, le mercure, l'indium et l'étain sont particulièrement bien adaptés. Toutefois, ce ne sont pas les seuls oxydes conducteurs que l'on peut utiliser. Parmi ces deux groupes d'éléments, le couple zirconium associé à un faible pourcentage d'étain donne de bons résultats.The addition element, the oxide of which is less resistant but has good electronic conductivity, is chosen from the metals of groups lb, IIb, IIIa or IVa of the periodic table. Among these metals, copper, silver, mercury, indium and tin are particularly well suited. However, these are not the only conductive oxides that can be used. Among these two groups of elements, the zirconium couple associated with a small percentage of tin gives good results.

En ce qui concerne les proportions relatives du métal et de l'élément d'addition, il est absolument nécessaire que les éléments d'addition restent en solution solide dans la matrice de base. La concentration maximale d'élément d'addition correspond à la limite de solubilité dans la matrice métallique. Toutes ces limites de solubilité ne sont pas connues, toutefois, on connaît celles de l'étain dans le zirconium. Celle-ci est de 17% atomique.As regards the relative proportions of the metal and the addition element, it is absolutely necessary that the addition elements remain in solid solution in the base matrix. The maximum concentration of additive element corresponds to the limit of solubility in the metal matrix. Not all of these solubility limits are known, however, those of tin in zirconium are known. This is 17 atomic%.

La concentration minimale d'éléments d'addition dans l'alliage est celle correspondant à la proportion suffisante pour qu'un phénomène de percolation puisse ultérieurement se produire dans l'étape finale. Cette concentration est approximativement de 0,1% atomique.The minimum concentration of addition elements in the alloy is that corresponding to the proportion sufficient for a percolation phenomenon to occur later in the final step. This concentration is approximately 0.1 atomic%.

On a pu observer que les matériaux possédant cette structure particulière présentaient de bonnes propriétés de conducteurs, tout en étant résistants physiquement et chimiquement.It has been observed that materials having this particular structure have good conductive properties, while being physically and chemically resistant.

Un procédé de fabrication du matériau selon l'invention va maintenant être décrit en détail.A method of manufacturing the material according to the invention will now be described in detail.

Ce procédé comprend une première étape consistant à prendre ou à préparer un alliage comprenant un métal dont l'oxyde est inaltérable et isolant et un élément d'addition dont l'oxyde est un conducteur électronique avec les métaux et éléments précédemment décrits.This method comprises a first step consisting in taking or preparing an alloy comprising a metal whose oxide is unalterable and insulating and an addition element whose oxide is an electronic conductor with the metals and elements previously described.

L'étape suivante du procédé selon l'invention consiste à faire subir à cet alliage une oxydation. Cette oxydation permet de rendre le métal de base inaltérable puisque déjà oxydé et de créer des précipités conducteurs dans la matrice d'oxyde. L'oxydation peut être réalisée par exemple par anodisation, par oxydation à sec ou par action d'un oxydant gazeux, liquide ou dissous, ce dernier pouvant être de l'eau ou de la vapeur d'eau.The next step in the process according to the invention consists in subjecting this alloy to oxidation. This oxidation makes the base metal unalterable since already oxidized and creates conductive precipitates in the oxide matrix. The oxidation can be carried out, for example, by anodization, by dry oxidation or by the action of a gaseous, liquid or dissolved oxidant, the latter possibly being water or water vapor.

L'oxydation peut être réalisée soit sous forme massive, soit sous forme d'un revêtement déposé directement sur une pièce métallique afin de lui conférer les propriétés d'inaltérabilité et de conductibilité électronique recherchées.Oxidation can be carried out either in massive form, or in the form of a coating deposited directly on a metal part in order to give it the desired properties of inalterability and electronic conductivity.

La réalisation du procédé selon l'invention doit répondre à deux objectifs principaux, d'une part, permettre la fabrication rapide de films de matériau conducteur de haute dureté et d'autre part, d'obtenir des films compacts, c'est-à-dire sans défauts mécaniques tels que des pores ou des fissures. Or, en général, plus une oxydation est rapide et moins le film obtenu est compact. Il faut donc trouver un compromis entre la qualité mécanique du film et sa vitesse de fabrication. Pour obtenir des films de matériaux minces, d'une épaisseur inférieure à 0,5 µm, l'anodisation est le mode d'oxydation le mieux adapté. En revanche, pour les films plus épais, l'oxydation dans de la vapeur d'eau à 400°C environ donne de très bons résultats, avec une vitesse d'oxydation de 1 à 2 µm par semaine.The implementation of the method according to the invention must meet two main objectives, on the one hand, to allow the rapid production of films of conductive material of high hardness and on the other hand, to obtain compact films, that is to say - say without mechanical defects such as pores or cracks. However, in general, the faster an oxidation and the less compact the film obtained. It is therefore necessary to find a compromise between the mechanical quality of the film and its speed of manufacture. To obtain films of thin materials, with a thickness of less than 0.5 μm, anodization is the most suitable oxidation mode. On the other hand, for thicker films, oxidation in water vapor at around 400 ° C. gives very good results, with a speed oxidation of 1 to 2 µm per week.

Enfin, la troisième étape du proc d de fabrication selon l'invention consiste à faire subir un traitement physique à l'alliage oxydé afin de créer par un phénomène de percolation des chemins conducteurs interconnectés dans la couche d'oxyde isolante. La percolation est un phénomène physique qui permet à certains transferts de s'effectuer dans un solide. Lorsque ce traitement de percolation est effectué, les charges électriques peuvent transiter en suivant des chemins particuliers au sein de l'oxyde non conducteur. Le traitement de percolation est décrit par exemple dans un ouvrage intitulé "Introduction to percolation theory", (Introduction à la théorie de la percolation), Stauffer D., Aharony A., London : Taylor and Francis, 1992.Finally, the third step of the manufacturing process according to the invention consists in subjecting the oxidized alloy to physical treatment in order to create, by a percolation phenomenon, conductive paths interconnected in the insulating oxide layer. Percolation is a physical phenomenon that allows certain transfers to take place in a solid. When this percolation treatment is carried out, the electric charges can pass by following particular paths within the non-conductive oxide. The percolation treatment is described for example in a book entitled "Introduction to percolation theory", (Introduction to the theory of percolation), Stauffer D., Aharony A., London: Taylor and Francis, 1992.

L'étape d'oxydation a permis de réaliser des précipités ou îlots d'oxyde conducteurs qui sont reliés entre eux par ce traitement de percolation. Ce traitement de percolation est généralement effectué par un traitement thermique. Celui-ci a pour rôle de créer les connexions nécessaires, si la nature et la concentration des constituants le permettent. Les gammes de concentration ont été données préalablement. Au cours de ce traitement thermique, la structure de l'alliage doit rester la même qu'à la température normale d'utilisation. Il faut donc opérer à une température inférieure à celle où un changement de phase commence à se produire (température de transition de phase). Cette température dépend bien entendu du matériau considéré.The oxidation step made it possible to produce precipitates or islets of conductive oxide which are linked together by this percolation treatment. This percolation treatment is generally carried out by a heat treatment. Its role is to create the necessary connections, if the nature and concentration of the constituents allow it. The concentration ranges have been given beforehand. During this heat treatment, the structure of the alloy must remain the same as at normal temperature of use. It is therefore necessary to operate at a temperature lower than that where a phase change begins to occur (phase transition temperature). This temperature naturally depends on the material considered.

Ce traitement physique peut être réalisé par un traitement thermique global ou au contraire par un traitement thermique local, destiné à ne rendre conductrice qu'une surface limitée de la pièce considérée. Dans ce dernier cas, seule une partie de la pièce est conductrice et on peut bénéficier des propriétés d'isolant sur le reste de la surface de celle-ci.This physical treatment can be carried out by a global heat treatment or on the contrary by a local heat treatment, intended to make conductive only a limited surface of the part considered. In the latter case, only part of the part is conductive and one can benefit from the insulating properties on the rest of the surface thereof.

Un exemple de réalisation particulier d'un matériau selon l'invention va maintenant être décrit.A particular embodiment of a material according to the invention will now be described.

Exemple : Example :

Des alliages de zirconium et d'étain connus sous la dénomination commerciale ZIRCALOY 2 et ZIRCALOY 4 ont été oxydés à 400°C dans de la vapeur d'eau, en les plaçant dans un autoclave adapté à ce type d'opération. L'oxydation a duré 1 à 2 semaines selon l'épaisseur souhaitée pour le film d'oxyde. Ensuite, le matériau oxydé a été placé dans un four sous vide primaire, puis chauffé pendant 1 à 2 heures à une température comprise entre 400 et 600°C pour rendre conductrice la couche d'oxyde. Ensuite, on a procédé à un refroidissement rapide du matériau en introduisant dans le four un gaz inerte tel que de l'argon ou de l'hélium.Zirconium and tin alloys known under the trade name ZIRCALOY 2 and ZIRCALOY 4 were oxidized at 400 ° C in water vapor, placing them in an autoclave suitable for this type of operation. The oxidation lasted 1 to 2 weeks depending on the thickness desired for the oxide film. Then, the oxidized material was placed in an oven under primary vacuum, then heated for 1 to 2 hours at a temperature between 400 and 600 ° C to make the oxide layer conductive. Then, the material was rapidly cooled by introducing an inert gas such as argon or helium into the furnace.

On a obtenu ainsi sur une pièce en alliage de zirconium, une couche résistante à l'oxydation, à l'abrasion et à l'usure tout en permettant le passage des électrons. La conductibilité observée est de type métallique comme l'ont prouvé les essais en laboratoire effectués sur ce produit.There was thus obtained on a piece of zirconium alloy, a layer resistant to oxidation, abrasion and wear while allowing the passage of electrons. The conductivity observed is of metallic type as proved by the laboratory tests carried out on this product.

Claims (18)

  1. High-hardness conductive material, characterized in that it consists of an alloy including a first oxide of a metal, this first insulating and non-corrodible oxide forming the metallic matrix of the material and a second oxide of an additive element forming an electronic conductor, various islands constituting this second oxide being connected together to form a conductive pathway within the said matrix.
  2. High-hardness conductive material according to Claim 1, characterized in that the metal is chosen from the elements of IVb or Vb Groups of the Periodic Table of the Elements.
  3. High-hardness conductive material according to Claim 1, characterized in that the additive element is chosen from the elements of Ib, IIb, IIIa or IVa Groups of the Periodic Table of the Elements.
  4. High-hardness conductive material according to Claim 2, characterized in that the metal is chosen from titanium, zirconium or niobium.
  5. High-hardness conductive material according to Claim 3, characterized in that the additive element is chosen from copper, silver, mercury, indium or tin.
  6. High-hardness conductive material according to any one of Claims 1 to 5, characterized in that the first oxide is a zirconium oxide and in that the second oxide is a tin oxide.
  7. High-hardness conductive material according to any one of the preceding claims, characterized in that the concentration of the additive element in the alloy is between 0.1 atomic % and the value corresponding to their limit of solubility in the metallic matrix.
  8. Process for manufacturing a high-hardness conductive material according to any one of Claims 1 to 7, characterized in that it includes the steps consisting in:
    - taking an alloy which includes a metal whose oxide is non-corrodible and insulating and an additive element whose oxide is an electronic conductor,
    - oxidizing this alloy, and
    - subjecting this oxidized alloy to a physical treatment so as to create, via a percolation phenomenon, interconnected conductive pathways in the insulating oxide layer.
  9. Process for manufacturing a high-hardness conductive material according to Claim 8, characterized in that the metal whose oxide is insulating is chosen from the elements of IVb or Vb Groups of the Periodic Table of the Elements.
  10. Process for manufacturing a high-hardness conductive material according to Claim 9, characterized in that the metal is chosen from titanium, zirconium or niobium.
  11. Process for manufacturing a high-hardness conductive material according to Claim 8, characterized in that the additive element is chosen from the elements of groups Ib, IIb, IIIa or IVa of the Periodic Table of the Elements.
  12. Process for manufacturing a high-hardness conductive material according to Claim 11, characterized in that the additive element is chosen from copper, silver, mercury, indium or tin.
  13. Process for manufacturing a high-hardness conductive material according to any one of Claims 8 to 12, characterized in that the concentration of the additive element in the alloy is between 0.1 atom % and the value corresponding to their limit of solubility in the metallic matrix.
  14. Process for manufacturing a high-hardness conductive material according to any one of Claims 8 to 13, characterized in that the alloy is in the form of a thin film having a thickness of less than 0.5 µm.
  15. Process for manufacturing a high-hardness conductive material according to Claim 14, characterized in that the oxidation of the alloy is produced by anodizing.
  16. Process for manufacturing a high-hardness conductive material, according to any one of Claims 8 to 13, characterized in that the alloy is in the form of a thick film, greater than 0.5 µm.
  17. Process for manufacturing a high-hardness conductive material according to Claim 16, characterized in that the oxidation of the alloy is produced by the action of a gaseous, liquid or dissolved oxidizing agent, at a temperature in the vicinity of 400°C.
  18. Process for manufacturing a high-hardness conductive material according to Claim 13, characterized in that the physical treatment producing the percolation is a heat treatment carried out at a temperature below the phase transition temperature of the alloy in question.
EP93904133A 1992-01-30 1993-01-28 High-hardness conductive material and method for manufacturing same Expired - Lifetime EP0624206B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9201026 1992-01-30
FR9201026A FR2686903B1 (en) 1992-01-30 1992-01-30 HIGH HARDNESS CONDUCTIVE MATERIAL AND METHOD FOR MANUFACTURING THE SAME.
PCT/FR1993/000089 WO1993015240A1 (en) 1992-01-30 1993-01-28 High-hardness conductive material and method for manufacturing same

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EP0624206A1 EP0624206A1 (en) 1994-11-17
EP0624206B1 true EP0624206B1 (en) 1995-10-11

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR902206A (en) * 1943-02-27 1945-08-22 Philips Nv Process for surface hardening of metal alloys and objects made with these hardened alloys
DE1173764B (en) * 1957-05-23 1964-07-09 Siemens Ag Process for the production of abrasion-resistant surface layers of great hardness and conductivity, in particular for electrical sliding and friction contacts
NL260208A (en) * 1960-02-16
DE1807906B2 (en) * 1968-01-27 1971-09-09 PROCESS FOR MANUFACTURING HIGH STRENGTH, ELECTRICALLY HIGH CONDUCTIVE AND THERMAL RESISTANT MATERIALS
US3922180A (en) * 1970-04-01 1975-11-25 Bell Telephone Labor Inc Method for oxidation-hardening metal alloy compositions, and compositions and structures therefrom
USRE31902E (en) * 1980-05-02 1985-05-28 Scm Corporation Dispersion strengthened metals

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DE69300632T2 (en) 1996-05-09
EP0624206A1 (en) 1994-11-17
FR2686903B1 (en) 1994-03-18
DE69300632D1 (en) 1995-11-16
WO1993015240A1 (en) 1993-08-05
FR2686903A1 (en) 1993-08-06

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