EP1272691B1 - Electrolytic solution for electrochemical deposit of palladium or its alloys - Google Patents

Electrolytic solution for electrochemical deposit of palladium or its alloys Download PDF

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Publication number
EP1272691B1
EP1272691B1 EP01921482A EP01921482A EP1272691B1 EP 1272691 B1 EP1272691 B1 EP 1272691B1 EP 01921482 A EP01921482 A EP 01921482A EP 01921482 A EP01921482 A EP 01921482A EP 1272691 B1 EP1272691 B1 EP 1272691B1
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Prior art keywords
palladium
electrolysis bath
bath according
baths
sulfate
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EP01921482A
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German (de)
French (fr)
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EP1272691A1 (en
Inventor
José GONZALEZ
Lionel Chalumeau
Michel Limayrac
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Metalor Technologies France Sas
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Metalor Technologies France Sas
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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
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals
    • C25D3/52—Electroplating: Baths therefor from solutions of platinum group metals characterised by the organic bath constituents used
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/567—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of platinum group metals

Definitions

  • the present invention relates to an electrolytic bath intended for deposition electrochemical of palladium or its alloys as well as a process electroplating palladium or one of its alloys.
  • the electrical contacts and connectors used in the field of electronics use, in finishing, thin layers of precious metals, electrodeposited which must be of suitable gloss, good ductility, non-porous, corrosion-resistant, friction-resistant and have low contact resistances.
  • the industry began by using deposits, often referred to as "Hard Gold", of gold hardened with small amounts of nickel or codeposited cobalt. Palladium is a precious metal with a lower deposit density (12 g / cm 3 ) than "Hard Gold” deposits (17.3 g / cm 3 ), also with higher hardness and lower porosity. Cheaper, palladium and its alloys have been found suitable for replacing gold for most applications.
  • the industry uses thin deposits (also referred to as flash-type deposits) of gold on palladium or on palladium alloys for finishing.
  • the palladium alloys used are mainly palladium-nickel, or palladium-silver alloys.
  • the barrel, the vibrating basket, the attachment, the discontinuous metallization, continuously high speed, or the jet deposition, also known by the term “jet-plating” deposition, or with the pad are commonly used techniques, for electrodepositing palladium and its alloys.
  • the industry is constantly looking for electrolytic baths and more efficient processes. Palladium and its alloys are also used for decorative applications, as an undercoat or as a finish.
  • the palladium and alloy baths currently sold are mostly ammonia baths, most often containing ions chlorides. These baths remain nevertheless baths with strong nuisances, so much for the health of operators, that for corrosion of equipment, they require many maintenance and upkeep operations.
  • Ammonia tends to evaporate at room temperature, a lot of commercial baths and, in particular, so-called “high speed” baths, operate from 40 to 60 ° C. These baths generate strong gaseous fumes in the processing workshops; not only are these vapors irritating to the airways respiratory agents, but are corrosive to all copper metals surrounding, including for parts of parts not submerged in the electrolyte.
  • the ammoniacal baths are conventionally alkaline baths, operating in pH ranges between 8 and 13.
  • the alkalinity of the electrolyte promotes the passivation of nickel, which can cause a lack of adhesion of palladium alloy deposits.
  • the first baths of this type described were baths of pure palladium, in very acidic environments, without organic amines. They were difficult to use, In fact, at pH values between 0 and 3, the attack on the substrates is too great. In addition, many of these formulations contain chlorides.
  • a second type relates to baths of pure palladium or of alloy, which contain organic amines, operating from 40 to 65 ° C, but typically in a pH range from 9 to 12, therefore under strongly alkaline conditions. AT these high pH, at these temperatures, polyamines tend to evaporate strongly, and to carbonate quickly by generating crystallizations. On the other hand, in these conditions, the passivation of nickel-plated substrates is then even more important than in ammonia baths. To overcome the lack of grip, a pre-palladium is necessary as a preliminary. This increases the cost of these deposits.
  • a third type of bath of pure palladium containing organic amines is described in particular in US Pat. No. 4,278,514.
  • These baths of intermediate pH located from 3 to 7 generally contain phosphates, and use as a brightener an imide type compound, such as than succinimide.
  • the admissible current densities are less than 4 A / dm 2 .
  • these baths contain pure palladium and are therefore mainly intended for decoration.
  • the imide-type compounds are capable of improving the brightness of these baths of pure palladium at low current densities, but the maximum current densities giving brilliant deposits do not exceed 4 A / dm 2 . Furthermore, to obtain this brightening action, the imides are added in large quantities. However, imides are strong complexing agents and their concentration therefore has a strong influence on the complexing of any incorporated secondary metal. This makes it too difficult to control the composition of the alloys, under suitable gloss conditions.
  • the present invention precisely proposes an optimal formulation, to meet all these requirements.
  • a problem which arises particularly for electronic applications is that of finding an effective brightener with very high current density, in a non-ammoniacal medium. Indeed, as explained above, many brighteners, and this is in particular the case of imide type brighteners, only allow glossy deposits to be obtained at medium or low current densities. In non-ammoniacal baths, known commercial brighteners such as nicotinamide, or sulfonate-type compounds, are not able to extend the gloss of deposits at high current densities, in particular those between 15 and 150 A / dm 2 desired in so-called "high speed" plating baths.
  • US Patent 4,767,507 describes gold plating baths using uses two specific brighteners, namely 3- (3-pyridyl) acrylic acid or 3- (3-quinolyl) acrylic acid.
  • these brighteners can also be used in electrolyte baths intended for the electrochemical deposition of palladium or its alloys in the presence of ethylenediamine acting as an agent complexing palladium.
  • these brighteners are particularly active for the high densities of current, even in very low concentrations.
  • the invention made it possible to find conditions where, in the absence chlorides and ammonia, plating could be done without deposit of insoluble salts on the anodes, which makes it possible to envisage applications in "jet-plating" and in continuous selective metallization of the metallization type at buffer.
  • the invention relates to an aqueous electrolytic bath at acid pH for deposition electrochemical of palladium or its alloys comprising a compound of palladium, and optionally at least one compound of a secondary metal intended to be codeposited in the form of an alloy with palladium, and comprising in addition, ethylenediamine as a complexing agent for palladium and an agent organic brightener, characterized in that said brightening agent is 3- (3-pyridyl) acid acrylic, 3- (3-quinolyl) acrylic acid or a salt thereof, preferably one of their alkaline salts, for example a sodium or potassium.
  • the bath of the invention makes it possible to deposit palladium or alloys of palladium, in particular alloys containing from 60 to 100% of palladium and 40 to 0% of one or more secondary metals such as: nickel, cobalt, iron, indium, gold, silver, or tin.
  • the baths according to the present invention are completely ammonia-free, both in their constitution and in their maintenance.
  • ethylenediamine as complexing agent which, at acidic pH, is very not very volatile, there is no emission of irritating vapors for the tracks operators' respiratory systems. Can operate at 75 ° C, without actually smell noticeable, these baths therefore allow operating temperatures above those practiced with ammonia baths (40 to 60 ° C), which is interesting for high speed electronic filing.
  • the electrolytic baths of the invention are baths with a low pH acid, preferably at a pH between 3 and 5. Indeed, in this range of pH, the baths of the invention prove to be particularly stable. This pH range is particularly suitable for baths containing nickel or cobalt, the hydroxides may precipitate at pH between 6 and 7 and allow to avoid obtaining veiled deposits, as is the case for certain pH baths between 5 and 6.
  • the gloss of the deposits obtained is generally further increased by the presence of a secondary metal which plays the role of mineral shine and, in a way analogous to what is observed in acidic gold baths.
  • the electrolytic bath will advantageously contain between 0 and 60 g / l at least one metal acting as a mineral shine.
  • One of the features of the baths according to the present invention is that they operate at weakly acidic pH preferably between 3 and 5.
  • the baths of the invention are intended for deposition of palladium or its alloys, in particular alloys containing minus a secondary metal such as nickel, cobalt, iron, indium, gold, silver or tin in proportions of 0.1 to 40%.
  • the baths of the invention advantageously contain from 1 to 100 g / l of palladium.
  • they contain at least one metal secondary selected from the group consisting of nickel, cobalt, iron, indium, gold, silver and tin, at a concentration between 0.1 and 60g / l.
  • one of the essential constituents of the the invention is ethylenediamine which acts to complex and therefore dissolve the palladium in the bath.
  • This ethylenediamine is contained in the bath in sufficient amount to complex the palladium and make it soluble in said bath, preferably at a concentration between 2 and 200 ml / l.
  • the specific brightening agent used according to the invention namely the acid 3- (3-pyridyl) acrylic or 3- (3-quinolyl) acrylic acid or a salt thereof, is contained in the bath at concentrations advantageously between 0.01 and 3 g / l.
  • these two brighteners can be used at relatively low concentrations and with high current densities, in particular with current densities of up to 150 A / dm 2 , which makes it possible to envisage the application of the baths of the invention in particular as a high-speed bath for producing shiny deposits. They can also be used for jet plating and selective metallization applications.
  • the electrolytic baths of the invention can contain various additives conventionally used in electroplating baths such only conductive salts, buffers to stabilize the pH, agents wetting agents, additives intended to reduce the internal stresses of deposits Electrolytic.
  • the baths of the invention advantageously contain at least 20 g / l at least one conductive salt.
  • This conductive salt will advantageously be chosen from the group consisting of sodium sulfate, potassium sulfate and their mixtures.
  • the buffers intended to stabilize the pH will preferably be of the type acetic, citric, boric, lactic, malic, phthalic, acrylic, tartaric, oxalic or succinic.
  • wetting agents are used.
  • the agents preferred wetting agents according to the invention will be bromide or iodide of cetyltrimethylammonium.
  • the invention proposes conditions allowing in particular to totally avoid the use of chlorides.
  • the baths according to the present invention are advantageously without chlorides and the basic anion of these baths is advantageously sulphate.
  • He is in known effect that sulfate anions are often used in electroplating because they react much less easily to electrodes, than nitrites or sulfites, the concentrations of which are much more difficult to maintain at a stable level in the electrolyte. These composition fluctuations can lead to to veiled deposits.
  • the baths of the invention have very good stability.
  • the palladium in the form of a compound specifically adapted for this purpose is the subject of a request for patent filed on the same day as this application.
  • this compound which is in the form of a salt insoluble in water present the advantage of being able to be transformed in the presence of an excess of ethylenediamine into a soluble complex upon its introduction into the bath.
  • this compound makes it possible to introduce palladium with a significantly lower amount of counterions (sulfate) than in the prior art.
  • palladium was introduced into the electrolytic baths either in the form of one of its salts, for example its sulfate, or, where appropriate, directly as the water-soluble complex between the sulfate and ethylenediamine.
  • palladium is introduced into the electrolytic bath of the invention in a particularly advantageous form in the form of a solid salt of palladium sulfate and of ethylenediamine comprising from 31 to 41% by weight of palladium and in which the molar ratio [SO 4 ]: [Pd] is between 0.9 and 1.15 and the [ethylenediamine]: [Pd] ratio is between 0.8 and 1.2.
  • Secondary metals can also be introduced in the form of sulfate.
  • the secondary metals will advantageously introduced in the form of sulfates, carbonates, hydroxides or their mixtures.
  • the invention make it possible to extend the life of electroplating equipment by avoiding their corrosion.
  • the invention also relates to a process for the electrodeposition of palladium or a palladium alloy, characterized in that it comprises the electrolysis of an electrolytic bath as defined above by implementing current densities between 0.5 and 150 A / dm 2 .
  • the process of the invention is particularly advantageous. in electronic applications, where we try to work with a speed of maximum deposit and where the desired deposits should be, among other things, brilliant, ductile, non-porous. To obtain high productivity, the baths must operate under the highest possible current density and temperature and high agitation is often necessary. Ethylene diamine baths allow operating temperatures higher than that practiced with baths ammonia exposed to the generated gaseous fumes.
  • the specific gloss of the invention can be used in baths of palladium and palladium alloys, where it's also very effective, like bright at high current densities and even at very low concentrations.
  • the baths of the invention therefore admit current densities similar to, or greater than, the most efficient ammonia baths.
  • bright deposits of 0.1 to 6 ⁇ m can be produced at current densities between 0.5 to 150 A / dm 2 .
  • baths of the invention can also be used for lower speeds and densities of current and, in particular, in decoration applications.
  • the anodes are insoluble anodes, preferably platinum titanium, oxide coated platinum iridium or a precious metal such as platinum. Furthermore, the cathode is made of a metallized substrate.
  • the concentrations of palladium and alloy metals are related to metal.
  • This method of adding palladium to the electrolyte can be used for the first preparation of the bath, and for palladium readjustments during of operation.
  • This bath deposits the 80% palladium - 20% nickel alloy.
  • the deposit of 0.1 to 6 ⁇ m is mirror-gloss, ductile, with low contact resistance, hardness Vickers of 390 HV under 100 gf (measured according to ISO standard 4,516 (1980)).
  • the deposits checked according to iso 4524/3 (85), are non-porous, they have a good corrosion resistance and, for a thickness of 0.5 to 6 ⁇ m, they are conforms to the so-called "CASS TEST" test defined by standard ISO 9 227 (1990). Through elsewhere, they have good resistance to friction and pass the test positively says "BRITISH TELECOM".
  • This bath deposits the palladium alloy 75% - cobalt 25%, the deposit from 0.1 to 6 ⁇ m is mirror-gloss, ductile, with low contact resistance, hard.
  • the deposits are non-porous, they have good resistance to corrosion and friction.
  • the 0.2 to 6 ⁇ m deposit is mirror-gloss, white, ductile, without cracks.
  • the deposits are non-porous, they have good resistance corrosion and friction.
  • This bath deposits the palladium alloy 80% nickel 20%.
  • the deposit of 0.2 to 6 ⁇ m is mirror-gloss, white, ductile, without cracks. Deposits are no porous, they have good resistance to corrosion and friction.
  • This bath deposits the palladium alloy 70% - cobalt 30% for application decorative, the deposit of 0.2 to 6 ⁇ m is shiny-mirror, ductile, without cracks.
  • the deposits are non-porous, they have good resistance to corrosion and friction.

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  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
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Abstract

The invention relates to an aqueous electrolysis bath of acidic pH for the electrochemical deposition of palladium or its alloys, said bath comprising a palladium compound and optionally at least one compound of a secondary metal to be codeposited in the form of an alloy with the palladium, and also comprising ethylenediamine as a palladium complexing agent, and an organic brightening agent, in which bath said brightening agent is 3-(3-pyridyl)acrylic acid, 3-(3-quinolyl)acrylic acid or one of their salts. It further relates to a process for the electroplating of palladium or a palladium alloy which comprises operating an electrolysis bath as defined above by using current densities of between 0.5 and 150 A/dm<2>.

Description

La présente invention concerne un bain électrolytique destiné au dépôt électrochimique du palladium ou de ses alliages ainsi qu'un procédé d'électrodéposition du palladium ou d'un de ses alliages.The present invention relates to an electrolytic bath intended for deposition electrochemical of palladium or its alloys as well as a process electroplating palladium or one of its alloys.

Les contacts électriques et les connecteurs utilisés dans le domaine de l'électronique utilisent, en finition, de fines couches de métaux précieux, électrodéposés qui doivent être de brillance convenable, de bonne ductilité, non poreux, résistants à la corrosion, résistants au frottement et avoir de faibles résistances de contact. L'industrie a commencé par utiliser des dépôts, souvent désignés par "Hard Gold", d'or durci par de faibles quantités de nickel ou de cobalt codéposé. Le palladium est un métal précieux ayant une plus faible densité de dépôt (12 g/cm3) que les dépôts d'" Hard Gold " (17,3 g/cm3), avec aussi une dureté supérieure et une plus faible porosité. Moins chers, le palladium et ses alliages ont été jugés aptes à être substitués à l'or pour la plupart des applications. Pour une grande variété d'applications, l'industrie utilise en finition des dépôts de faible épaisseur (également désignés par dépôt de type flash) d'or sur palladium ou sur alliages de palladium. Les alliages de palladium utilisés sont principalement des alliages palladium-nickel, ou palladium-argent. Le tonneau, le panier vibrant, l'attache, la métallisation en discontinu, en continu haute vitesse, ou le dépôt au jet, encore désigné sous le vocable anglais dépôt en "jet-plating", ou au tampon sont des techniques couramment utilisées, pour électrodéposer le palladium et ses alliages. L'industrie recherche en permanence des bains électrolytiques et des procédés plus performants. Le palladium et ses alliages sont également utilisés pour les applications décoratives, en sous-couche ou en finition.The electrical contacts and connectors used in the field of electronics use, in finishing, thin layers of precious metals, electrodeposited which must be of suitable gloss, good ductility, non-porous, corrosion-resistant, friction-resistant and have low contact resistances. The industry began by using deposits, often referred to as "Hard Gold", of gold hardened with small amounts of nickel or codeposited cobalt. Palladium is a precious metal with a lower deposit density (12 g / cm 3 ) than "Hard Gold" deposits (17.3 g / cm 3 ), also with higher hardness and lower porosity. Cheaper, palladium and its alloys have been found suitable for replacing gold for most applications. For a wide variety of applications, the industry uses thin deposits (also referred to as flash-type deposits) of gold on palladium or on palladium alloys for finishing. The palladium alloys used are mainly palladium-nickel, or palladium-silver alloys. The barrel, the vibrating basket, the attachment, the discontinuous metallization, continuously high speed, or the jet deposition, also known by the term “jet-plating” deposition, or with the pad are commonly used techniques, for electrodepositing palladium and its alloys. The industry is constantly looking for electrolytic baths and more efficient processes. Palladium and its alloys are also used for decorative applications, as an undercoat or as a finish.

Etat de l'art concernant les bains ammoniacauxState of the art concerning ammonia baths

Les bains de palladium et d'alliages actuellement commercialisés sont majoritairement des bains ammoniacaux, contenant le plus souvent des ions chlorures. Ces bains restent néanmoins des bains à fortes nuisances, tant pour la santé des opérateurs, que pour la corrosion des équipements, ils nécessitent beaucoup d'opérations de maintenance et d'entretien.The palladium and alloy baths currently sold are mostly ammonia baths, most often containing ions chlorides. These baths remain nevertheless baths with strong nuisances, so much for the health of operators, that for corrosion of equipment, they require many maintenance and upkeep operations.

L'ammoniaque tend à s'évaporer à température ambiante, beaucoup de bains commercialisés et, en particulier, les bains dits "haute vitesse", fonctionnent de 40 à 60°C. Ces bains engendrent de fortes émanations gazeuses dans les ateliers de traitement ; ces vapeurs non seulement sont irritantes pour les voies respiratoires des opérateurs, mais sont corrosives pour tous les métaux cuivreux environnants, y compris pour les parties des pièces non immergées dans l'électrolyte.Ammonia tends to evaporate at room temperature, a lot of commercial baths and, in particular, so-called "high speed" baths, operate from 40 to 60 ° C. These baths generate strong gaseous fumes in the processing workshops; not only are these vapors irritating to the airways respiratory agents, but are corrosive to all copper metals surrounding, including for parts of parts not submerged in the electrolyte.

Par ailleurs, l'intense évaporation d'ammoniaque, engendre une diminution rapide du pH et du volume de ces électrolytes, et contraint les utilisateurs à d'incessants et coûteux ajouts d'ammoniaque et réglages de pH. Cette maintenance est indispensable, y compris après toute période d'arrêt d'utilisation de l'électrolyte.In addition, the intense evaporation of ammonia causes a reduction rapid pH and volume of these electrolytes, and forces users to incessant and costly additions of ammonia and pH adjustments. This maintenance is essential, including after any period of stopping use of the electrolyte.

Les bains ammoniacaux sont classiquement des bains alcalins, fonctionnant dans des gammes de pH entre 8 et 13. Lors de la métallisation sur du nickel par exemple, lors de l'immersion de la pièce, l'alcalinité de l'électrolyte favorise la passivation du nickel, qui peut engendrer un manque d'adhérence des dépôts d'alliage palladium.The ammoniacal baths are conventionally alkaline baths, operating in pH ranges between 8 and 13. When metallizing on nickel for example, during the immersion of the part, the alkalinity of the electrolyte promotes the passivation of nickel, which can cause a lack of adhesion of palladium alloy deposits.

Quand ils sont présents, les chlorures ajoutent encore d'autres désagréments:

  • La corrosion des équipements en acier inoxydable est facilitée, d'où des pollutions d'électrolytes.
  • Au cours de l'électrolyse un sel jaune insoluble de palladium est généré à la surface des anodes titane-platinées, d'où de multiples difficultés pour toutes les applications de type jet-plating ou métallisation sélective au tampon en continu.
When they are present, the chlorides add still other inconveniences:
  • Corrosion of stainless steel equipment is facilitated, resulting in pollution of electrolytes.
  • During the electrolysis an insoluble yellow salt of palladium is generated on the surface of the titanium-platinum anodes, hence multiple difficulties for all applications of the jet-plating type or selective metallization with continuous buffering.

Etat de l'art concernant les bains non ammoniacauxState of the art concerning non-ammoniacal baths

Les premiers bains de ce type décrits ont été des bains de palladium pur, en milieux très acides, sans amines organiques. Ils étaient difficilement utilisables, En effet, à des pH situés entre 0 et 3, l'attaque des substrats est trop importante. De plus beaucoup de ces formulations contiennent des chlorures.The first baths of this type described were baths of pure palladium, in very acidic environments, without organic amines. They were difficult to use, In fact, at pH values between 0 and 3, the attack on the substrates is too great. In addition, many of these formulations contain chlorides.

Un second type concerne des bains de palladium pur ou d'alliage, qui contiennent des amines organiques, fonctionnant de 40 à 65°C, mais typiquement dans une gamme de pH 9 à 12, donc dans des conditions fortement alcalines. A ces pH élevés, à ces températures, les polyamines tendent à s'évaporer fortement, et à se carbonater rapidement en générant des cristallisations. D'autre part, dans ces conditions, la passivation des substrats nickelés est alors encore plus importante que dans les bains ammoniacaux. Pour pallier le manque d'adhérence, un pré-palladiage est nécessaire de façon préliminaire. Ceci augmente d'autant le prix de revient de ces dépôts.A second type relates to baths of pure palladium or of alloy, which contain organic amines, operating from 40 to 65 ° C, but typically in a pH range from 9 to 12, therefore under strongly alkaline conditions. AT these high pH, at these temperatures, polyamines tend to evaporate strongly, and to carbonate quickly by generating crystallizations. On the other hand, in these conditions, the passivation of nickel-plated substrates is then even more important than in ammonia baths. To overcome the lack of grip, a pre-palladium is necessary as a preliminary. This increases the cost of these deposits.

Un troisième type de bains de palladium pur contenant des amines organiques est décrit en particulier dans le brevet US 4 278 514. Ces bains de pH intermédiaires situés de 3 à 7 contiennent généralement des phosphates, et utilisent comme brillanteur un composé de type imide, tel que le succinimide. Dans de tels bains, les densités de courant admissibles sont inférieures à 4 A/dm2. Par ailleurs, ces bains contiennent du palladium pur et sont donc principalement destinés à la décoration.A third type of bath of pure palladium containing organic amines is described in particular in US Pat. No. 4,278,514. These baths of intermediate pH located from 3 to 7 generally contain phosphates, and use as a brightener an imide type compound, such as than succinimide. In such baths, the admissible current densities are less than 4 A / dm 2 . Furthermore, these baths contain pure palladium and are therefore mainly intended for decoration.

Ces bains utilisent généralement des tampons phosphates efficaces pour les pH alcalins visés. Toutefois, dans certains cas, l'incorporation de traces de phosphore dans les dépôts peut influencer la qualité des dépôts, et en particulier nuire à leur brillance.These baths generally use effective phosphate buffers for targeted alkaline pH. However, in some cases the incorporation of traces of phosphorus in deposits can influence the quality of deposits, and in particular detract from their shine.

D'autre part, les composés de type imide sont capables d'améliorer la brillance de ces bains de palladium pur à faibles densités de courant, mais les densités de courant maximales donnant des dépôts brillants ne dépassent pas 4 A/dm2. Par ailleurs, pour obtenir cette action de brillantage les imides sont ajoutées en quantité importante. Or, les imides sont des complexants forts et leur concentration influe donc fortement sur la complexation de tout métal secondaire incorporé. Ceci rend trop difficile la maítrise de composition des alliages, dans des conditions de brillance convenable.On the other hand, the imide-type compounds are capable of improving the brightness of these baths of pure palladium at low current densities, but the maximum current densities giving brilliant deposits do not exceed 4 A / dm 2 . Furthermore, to obtain this brightening action, the imides are added in large quantities. However, imides are strong complexing agents and their concentration therefore has a strong influence on the complexing of any incorporated secondary metal. This makes it too difficult to control the composition of the alloys, under suitable gloss conditions.

Il existe donc un besoin pour un procédé nouveau, qui exclurait l'utilisation de l'ammoniaque, des chlorures, des phosphates, et des imides, et qui permettrait de déposer des alliages stables d'aspect brillant éventuellement à très haute vitesse, donnant des dépôts ductiles, adhérents sans pré-palladiage. Le pH de ces bains devrait rester dans la gamme des pH faiblement acides. Ces bains devraient en outre pouvoir être associés à un procédé de recharge en métal, capable d'éviter la concentration rapide des sels, de façon à obtenir une longue durée de vie.There is therefore a need for a new process, which would exclude the use ammonia, chlorides, phosphates, and imides, and that would depositing stable alloys with a shiny appearance, possibly at very high speed, giving ductile, adherent deposits without pre-palladium. The pH of these baths should remain in the weakly acidic pH range. These baths should Besides being able to be associated with a metal recharging process, capable of avoiding the rapid concentration of salts, so as to obtain a long service life.

Pour le moment, aucun procédé existant sur le marché n'est pleinement satisfaisant.For the moment, no existing process on the market is fully satisfactory.

La présente invention propose justement une formulation optimale, permettant de répondre à toutes ces exigences.The present invention precisely proposes an optimal formulation, to meet all these requirements.

Un problème qui se pose particulièrement pour les applications électroniques est celui de trouver un brillanteur efficace à très forte densité de courant, en milieu non ammoniacal. En effet, comme exposé précédemment, beaucoup de brillanteurs, et, c'est en particulier le cas des brillanteurs de type imide, ne permettent l'obtention de dépôts brillants qu'aux moyennes ou faibles densités de courant. Dans les bains non ammoniacaux, les brillanteurs commerciaux connus tels que le nicotinamide, ou les composés de type sulfonate, ne sont pas en mesure d'étendre la brillance des dépôts aux fortes densités de courant, en particulier à celles comprises entre 15 et 150 A/dm2 souhaitées dans les bains d'électrodéposition dits "haute vitesse".A problem which arises particularly for electronic applications is that of finding an effective brightener with very high current density, in a non-ammoniacal medium. Indeed, as explained above, many brighteners, and this is in particular the case of imide type brighteners, only allow glossy deposits to be obtained at medium or low current densities. In non-ammoniacal baths, known commercial brighteners such as nicotinamide, or sulfonate-type compounds, are not able to extend the gloss of deposits at high current densities, in particular those between 15 and 150 A / dm 2 desired in so-called "high speed" plating baths.

C'est en particulier, à la résolution de ce problème que s'adresse la présente invention en proposant l'utilisation de brillanteurs bien déterminés pouvant être utilisés dans les conditions idéales exposées ci-dessus.It is in particular, to the resolution of this problem that this present is addressed invention by proposing the use of well-defined brighteners which can be used under the ideal conditions set out above.

Le brevet US 4 767 507 décrit des bains d'électrodéposition d'or mettant en oeuvre deux brillanteurs spécifiques, à savoir l'acide 3-(3-pyridyl) acrylique ou l'acide 3-(3-quinolyl) acrylique.US Patent 4,767,507 describes gold plating baths using uses two specific brighteners, namely 3- (3-pyridyl) acrylic acid or 3- (3-quinolyl) acrylic acid.

Dans les bains d'or décrits dans ce document, ces brillanteurs démontrent une très bonne stabilité, même employés en très faibles quantités. Ils permettent d'étendre la brillance dans les hautes densités de courant.In the gold baths described in this document, these brighteners demonstrate very good stability, even when used in very small quantities. They allow to extend the shine in high current densities.

Il a maintenant été établi que ces brillanteurs peuvent également être utilisés dans des bains d'électrolytes destinés au dépôt électrochimique du palladium ou de ses alliages en présence d'éthylènediamine agissant comme agent complexant du palladium. Il a en particulier été mis en évidence que dans de tels bains, ces brillanteurs s'avèrent particulièrement actifs pour les fortes densités de courant, et cela, même en très faible concentration.It has now been established that these brighteners can also be used in electrolyte baths intended for the electrochemical deposition of palladium or its alloys in the presence of ethylenediamine acting as an agent complexing palladium. In particular, it has been highlighted that in such baths, these brighteners are particularly active for the high densities of current, even in very low concentrations.

Il a été ainsi possible, en utilisant ces brillanteurs de réaliser des bains pouvant être utilisés dans des procédés d'électrodéposition à haute vitesse, utilisant des densités de courant analogues ou même supérieures à celles utilisées dans les bains ammoniacaux les plus performants. Pour de telles applications, des dépôts brillants de 0,1 à 6 µm ont pu être réalisés à des densités de courant comprises entre 0,5 et 150 A/dm2.It has thus been possible, using these brighteners, to produce baths which can be used in high-speed electrodeposition processes, using current densities similar to or even higher than those used in the most efficient ammonia baths. For such applications, bright deposits of 0.1 to 6 µm could be produced at current densities between 0.5 and 150 A / dm 2 .

Par ailleurs l'invention a permis de trouver des conditions où, en l'absence de chlorures et d'ammoniaque, on pouvait réaliser l'électrodéposition sans dépôt de sels insolubles sur les anodes, ce qui permet d'envisager des applications en "jet-plating" et en métallisation sélective en continu du type métallisation au tampon.Furthermore, the invention made it possible to find conditions where, in the absence chlorides and ammonia, plating could be done without deposit of insoluble salts on the anodes, which makes it possible to envisage applications in "jet-plating" and in continuous selective metallization of the metallization type at buffer.

Plus précisément, selon l'une de ses caractéristiques essentielles, l'invention concerne un bain électrolytique aqueux à pH acide pour le dépôt électrochimique du palladium ou de ses alliages comprenant un composé du palladium, et de façon optionnelle au moins un composé d'un métal secondaire destiné à être codéposé sous forme d'alliage avec le palladium, et comprenant en outre, de l'éthylènediamine comme agent complexant du palladium et un agent brillanteur organique, caractérisé en ce que ledit agent brillanteur est l'acide 3-(3-pyridyl) acrylique, l'acide 3-(3-quinolyl) acrylique ou un de leurs sels, de préférence un de leurs sels alcalins, par exemple un sel de sodium ou de potassium.More precisely, according to one of its essential characteristics, the invention relates to an aqueous electrolytic bath at acid pH for deposition electrochemical of palladium or its alloys comprising a compound of palladium, and optionally at least one compound of a secondary metal intended to be codeposited in the form of an alloy with palladium, and comprising in addition, ethylenediamine as a complexing agent for palladium and an agent organic brightener, characterized in that said brightening agent is 3- (3-pyridyl) acid acrylic, 3- (3-quinolyl) acrylic acid or a salt thereof, preferably one of their alkaline salts, for example a sodium or potassium.

Le bain de l'invention permet de déposer du palladium ou des alliages de palladium, en particulier des alliages contenant de 60 à 100 % de palladium et de 40 à 0 % d'un ou plusieurs métaux secondaires tels que : nickel, cobalt, fer, indium, or, argent, ou étain.The bath of the invention makes it possible to deposit palladium or alloys of palladium, in particular alloys containing from 60 to 100% of palladium and 40 to 0% of one or more secondary metals such as: nickel, cobalt, iron, indium, gold, silver, or tin.

Les bains selon la présente invention sont totalement sans ammoniaque, tant dans leur constitution, que pour leur entretien.The baths according to the present invention are completely ammonia-free, both in their constitution and in their maintenance.

Ils utilisent comme complexant l'éthylènediamine qui, à pH acide, est très peu volatile, il n'y a pas d'émission de vapeurs irritantes pour les voies respiratoires des opérateurs. Pouvant fonctionner à 75°C, sans odeur réellement perceptible, ces bains autorisent donc des températures opératoires supérieures à celles pratiquées avec les bains ammoniacaux (40 à 60°C), ce qui est intéressant pour les dépôts électroniques à haute vitesse.They use ethylenediamine as complexing agent which, at acidic pH, is very not very volatile, there is no emission of irritating vapors for the tracks operators' respiratory systems. Can operate at 75 ° C, without actually smell noticeable, these baths therefore allow operating temperatures above those practiced with ammonia baths (40 to 60 ° C), which is interesting for high speed electronic filing.

En l'absence de vapeurs corrosives, les métaux cuivreux environnants ne sont pas attaqués, et il n'y a pas de pollution en cuivre du bain. Nombre d'opérations de décapage et de nettoyage sont ainsi évitées.In the absence of corrosive vapors, the surrounding copper metals do not are not attacked, and there is no copper pollution of the bath. Number pickling and cleaning operations are thus avoided.

Pour les mêmes raisons, le pH reste inchangé en l'absence d'électrolyse et lors des électrolyses les ajustements de pH sont beaucoup moins importants. Les variations de volume du bain ne correspondent qu'aux seules évaporation d'eau, à la température de travail ainsi qu'aux pertes par entraínement.For the same reasons, the pH remains unchanged in the absence of electrolysis and during electrolysis the pH adjustments are much less important. The variations in the volume of the bath correspond only to the evaporation of water, to the working temperature and losses by training.

Les bains électrolytiques de l'invention sont des bains à pH faiblement acide, de préférence à un pH compris entre 3 et 5. En effet, dans cette gamme de pH, les bains de l'invention s'avèrent particulièrement stables. Cette gamme de pH est particulièrement adaptée aux bains contenant du nickel ou du cobalt dont les hydroxydes risqueraient de précipiter à des pH compris entre 6 et 7 et permet d'éviter d'obtenir des dépôts voilés, comme c'est le cas pour certains bains à pH compris entre 5 et 6.The electrolytic baths of the invention are baths with a low pH acid, preferably at a pH between 3 and 5. Indeed, in this range of pH, the baths of the invention prove to be particularly stable. This pH range is particularly suitable for baths containing nickel or cobalt, the hydroxides may precipitate at pH between 6 and 7 and allow to avoid obtaining veiled deposits, as is the case for certain pH baths between 5 and 6.

Dans l'intervalle préféré de pH compris entre 3 et 5, la brillance des dépôts obtenus est encore généralement accrue par la présence d'un métal secondaire qui joue le rôle de brillanteur minéral et, cela d'une façon analogue à ce qui est observé dans les bains d'or acides.In the preferred pH range of 3 to 5, the gloss of the deposits obtained is generally further increased by the presence of a secondary metal which plays the role of mineral shine and, in a way analogous to what is observed in acidic gold baths.

Ainsi, le bain électrolytique contiendra avantageusement entre 0 et 60 g/l d'au moins un métal agissant comme brillanteur minéral.Thus, the electrolytic bath will advantageously contain between 0 and 60 g / l at least one metal acting as a mineral shine.

L'une des particularités des bains selon de la présente invention est qu'ils fonctionnent à des pH faiblement acides de préférence compris entre 3 et 5. One of the features of the baths according to the present invention is that they operate at weakly acidic pH preferably between 3 and 5.

Ces bains n'ont donc pas les inconvénients des premiers bains trop acides susceptibles d'attaquer le substrat, ils ne nécessitent néanmoins pas de pré-palladiage. A l'inverse à ces pH, un substrat nickelé ne se passive pas à l'entrée dans l'électrolyte comme avec les bains alcalins, le dépôt est toujours très adhérent.These baths therefore do not have the disadvantages of the first too acidic baths likely to attack the substrate, they do not however require pre-palladium. Conversely at these pHs, a nickel-plated substrate is not passive at the input in the electrolyte as with the alkaline baths, the deposit is always very member.

Ces valeurs de pH et la possibilité de déposer à température élevée, sont les conditions les plus favorables à l'obtention de dépôts non poreux.These pH values and the possibility of depositing at high temperature are the most favorable conditions for obtaining non-porous deposits.

Comme exposé précédemment les bains de l'invention sont destinés au dépôt de palladium ou de ses alliages, en particulier des alliages contenant au moins un métal secondaire tel que le nickel, le cobalt, le fer, l'indium, l'or, l'argent ou l'étain dans des proportions de 0,1 à 40 %.As explained above, the baths of the invention are intended for deposition of palladium or its alloys, in particular alloys containing minus a secondary metal such as nickel, cobalt, iron, indium, gold, silver or tin in proportions of 0.1 to 40%.

Les bains de l'invention contiennent avantageusement de 1 à 100 g/l de palladium.The baths of the invention advantageously contain from 1 to 100 g / l of palladium.

Selon une autre variante de l'invention, ils contiennent au moins un métal secondaire choisi dans le groupe constitué du nickel, du cobalt, du fer, de l'indium, de l'or, de l'argent et de l'étain, à une concentration comprise entre 0,1 et 60g/l.According to another variant of the invention, they contain at least one metal secondary selected from the group consisting of nickel, cobalt, iron, indium, gold, silver and tin, at a concentration between 0.1 and 60g / l.

Comme exposé précédemment, un des constituants essentiels du bain de l'invention est l'éthylènediamine qui agit pour complexer et donc solubiliser le palladium au sein du bain. Cette éthylènediamine est contenue dans le bain en quantité suffisante, pour complexer le palladium et le rendre soluble dans ledit bain, de préférence à une concentration comprise entre 2 et 200 ml/l.As previously stated, one of the essential constituents of the the invention is ethylenediamine which acts to complex and therefore dissolve the palladium in the bath. This ethylenediamine is contained in the bath in sufficient amount to complex the palladium and make it soluble in said bath, preferably at a concentration between 2 and 200 ml / l.

Enfin, l'agent brillanteur spécifique utilisé selon l'invention, à savoir l'acide 3-(3-pyridyl) acrylique ou l'acide 3-(3-quinolyl) acrylique ou un de leurs sels, est contenu dans le bain à des concentrations avantageusement comprises entre 0,01 et 3 g/l.Finally, the specific brightening agent used according to the invention, namely the acid 3- (3-pyridyl) acrylic or 3- (3-quinolyl) acrylic acid or a salt thereof, is contained in the bath at concentrations advantageously between 0.01 and 3 g / l.

Parmi ces deux brillanteurs, on utilisera de façon particulièrement avantageuse l'acide 3-(3 pyridyl) acrylique et, plus particulièrement, l'isomère trans de cet acide.Among these two brighteners, we will particularly use advantageous 3- (3 pyridyl) acrylic acid and, more particularly, the isomer trans of this acid.

Comme exposé précédemment, ces deux brillanteurs, à la différence des brillanteurs de l'art antérieur peuvent être utilisés à des concentrations relativement basses et avec des densités de courant élevées, en particulier avec des densités de courant pouvant aller jusqu'à 150 A/dm2, ce qui permet d'envisager l'application des bains de l'invention en particulier en tant que bain haute vitesse pour réaliser des dépôts brillants. Ils peuvent également être utilisés pour des applications de type "jet plating" et de métallisation sélective en continu. As explained above, these two brighteners, unlike the brighteners of the prior art, can be used at relatively low concentrations and with high current densities, in particular with current densities of up to 150 A / dm 2 , which makes it possible to envisage the application of the baths of the invention in particular as a high-speed bath for producing shiny deposits. They can also be used for jet plating and selective metallization applications.

Par ailleurs, les bains électrolytiques de l'invention peuvent contenir différents additifs classiquement utilisés dans les bains d'électrodéposition tels que des sels conducteurs, des tampons destinés à stabiliser le pH, des agents mouillants, des additifs destinés à réduire les tensions internes des dépôts électrolytiques.Furthermore, the electrolytic baths of the invention can contain various additives conventionally used in electroplating baths such only conductive salts, buffers to stabilize the pH, agents wetting agents, additives intended to reduce the internal stresses of deposits Electrolytic.

On choisira avantageusement ces différents additifs de façon à ce qu'ils n'introduisent pas d'ions non désirés dans le bain électrolytique et, en particulier, de façon à ce qu'ils n'introduisent dans le bain électrolytique ni chlorure, ni acide phosphorique.These different additives will advantageously be chosen so that they do not introduce unwanted ions into the electrolytic bath and, in particular, so that they do not introduce chloride or acid into the electrolytic bath phosphoric.

Ainsi, les bains de l'invention contiennent avantageusement au moins 20g/l d'au moins un sel conducteur. Ce sel conducteur sera avantageusement choisi dans le groupe constitué du sulfate de sodium, du sulfate de potassium et de leurs mélanges.Thus, the baths of the invention advantageously contain at least 20 g / l at least one conductive salt. This conductive salt will advantageously be chosen from the group consisting of sodium sulfate, potassium sulfate and their mixtures.

Les tampons destinés à stabiliser le pH seront de préférence de type acétique, citrique, borique, lactique, malique, phtalique, acrylique, tartrique, oxalique ou succinique.The buffers intended to stabilize the pH will preferably be of the type acetic, citric, boric, lactic, malic, phthalic, acrylic, tartaric, oxalic or succinic.

On recourra avantageusement à des agents mouillants. Les agents mouillants préférés selon l'invention seront le bromure ou l'iodure de céthyltriméthylammonium.Advantageously, wetting agents are used. The agents preferred wetting agents according to the invention will be bromide or iodide of cetyltrimethylammonium.

Pour éviter les tensions internes on choisira avantageusement d'incorporer dans le bain électrolytique du saccharinate de sodium.To avoid internal tensions, it is advantageous to choose to incorporate in the electrolytic bath of sodium saccharinate.

Selon différentes variantes particulièrement avantageuses, l'invention propose des conditions permettant en particulier d'éviter totalement l'utilisation de chlorures.According to different particularly advantageous variants, the invention proposes conditions allowing in particular to totally avoid the use of chlorides.

Elle propose également des conditions où l'on évite au maximum de charger le bain en ions et, cela, de façon à améliorer sa durée de vie.It also proposes conditions where maximum avoidance of charge the bath with ions and this in order to improve its lifespan.

Ainsi, pour éviter l'utilisation de chlorures, on introduit avantageusement le palladium sous forme de sulfate.Thus, to avoid the use of chlorides, it is advantageous to introduce palladium in the form of sulfate.

Ainsi, les bains selon la présente invention sont avantageusement sans chlorures et l'anion de base de ces bains est avantageusement le sulfate. Il est en effet connu que les anions sulfates sont souvent utilisés en galvanoplastie, car ils réagissent beaucoup moins facilement aux électrodes, que les ions nitrites ou sulfites, dont les concentrations sont beaucoup plus difficiles à maintenir à un niveau stable dans l'électrolyte. Ces fluctuations de composition peuvent conduire à des dépôts voilés. Contrairement à ces formulations, les bains de l'invention ont une très bonne stabilité. Thus, the baths according to the present invention are advantageously without chlorides and the basic anion of these baths is advantageously sulphate. He is in known effect that sulfate anions are often used in electroplating because they react much less easily to electrodes, than nitrites or sulfites, the concentrations of which are much more difficult to maintain at a stable level in the electrolyte. These composition fluctuations can lead to to veiled deposits. Unlike these formulations, the baths of the invention have very good stability.

Par ailleurs, il est bien connu que la durée de vie d'un bain de galvanoplastie peut être largement prolongée en évitant l'accumulation des espèces chimiques au cours du fonctionnement de ce bain, de façon à éviter de saturer l'électrolyte.Furthermore, it is well known that the lifetime of a electroplating can be largely prolonged avoiding the accumulation of species chemicals during the operation of this bath, so as to avoid saturating the electrolyte.

C'est ainsi que, selon l'invention, on introduit avantageusement le palladium sous forme d'un composé spécifiquement adapté à cet effet. Ce composé qui est en lui-même un composé nouveau fait l'objet d'une demande de brevet déposée le même jour que la présente demande. Plus précisément, ce composé qui se présente sous forme d'un sel insoluble dans l'eau présente l'avantage de pouvoir être transformé en présence d'un excès d'éthylènediamine en un complexe soluble dès son introduction dans le bain. Par ailleurs, du fait de sa composition chimique, ce composé permet d'introduire le palladium avec une quantité de contre-ions (sulfate) nettement plus faible que dans l'art antérieur. En effet, dans l'art antérieur on introduisait dans les bains électrolytiques le palladium soit sous forme d'un de ses sels, par exemple de son sulfate soit, le cas échéant, directement sous forme du complexe soluble dans l'eau entre le sulfate et l'éthylènediamine.Thus, according to the invention, the palladium in the form of a compound specifically adapted for this purpose. This compound which is in itself a new compound is the subject of a request for patent filed on the same day as this application. Specifically, this compound which is in the form of a salt insoluble in water present the advantage of being able to be transformed in the presence of an excess of ethylenediamine into a soluble complex upon its introduction into the bath. Furthermore, due to its chemical composition, this compound makes it possible to introduce palladium with a significantly lower amount of counterions (sulfate) than in the prior art. In indeed, in the prior art, palladium was introduced into the electrolytic baths either in the form of one of its salts, for example its sulfate, or, where appropriate, directly as the water-soluble complex between the sulfate and ethylenediamine.

Plus précisément, le palladium est introduit dans le bain électrolytique de l'invention de façon particulièrement avantageuse sous forme d'un sel solide de sulfate de palladium et d'éthylènediamine comprenant de 31 à 41 % en poids de palladium et dans lequel le rapport molaire [SO4] : [Pd] est compris entre 0,9 et 1,15 et le rapport [éthylènediamine] : [Pd] est compris entre 0,8 et 1,2.More specifically, palladium is introduced into the electrolytic bath of the invention in a particularly advantageous form in the form of a solid salt of palladium sulfate and of ethylenediamine comprising from 31 to 41% by weight of palladium and in which the molar ratio [SO 4 ]: [Pd] is between 0.9 and 1.15 and the [ethylenediamine]: [Pd] ratio is between 0.8 and 1.2.

Une méthode de synthèse du sulfate de palladium complexé par une seule éthylènediamine sous forme de sel solide a été spécialement mise au point. Ce sel, bien qu'insoluble dans l'eau est soluble dans les bains où un excès d'agent complexant est toujours présent. Ce sel est très intéressant pour réajuster la concentration en palladium, sa fabrication est détaillée plus loin.A method for the synthesis of palladium sulfate complexed by a single ethylenediamine in the form of a solid salt has been specially developed. This salt, although insoluble in water is soluble in baths where an excess of agent complexing is always present. This salt is very interesting to readjust the palladium concentration, its manufacture is detailed below.

Toujours avec le même souci d'éviter de charger le bain électrolytique en contre-ions, quand un ou plusieurs métaux d'alliage sont codéposés, donc consommés, la recharge des bains en ces métaux sous forme de carbonates s'est révélée la plus adaptée. En effet les carbonates réagissent en milieu acide pour former du CO2 qui s'échappe rapidement sous forme gazeuse au moment de l'addition. CO3 2- + 2 H+ → H2O + CO2 ↗ Always with the same concern of avoiding charging the electrolytic bath with counter-ions, when one or more alloy metals are codeposited, therefore consumed, recharging the baths in these metals in the form of carbonates has proved to be the most suitable. . Indeed, the carbonates react in an acid medium to form CO 2 which escapes quickly in gaseous form at the time of the addition. CO 3 2- + 2 H + → H 2 O + CO 2 ↗

Cette réaction a lieu, lorsque le carbonate du métal est ajouté à l'électrolyte. Avec ce système, les métaux secondaires peuvent être réajustés sans laisser aucun anion dans le bain. Ce système permet donc de prolonger la vie des bains de la présente invention.This reaction takes place when the carbonate of the metal is added to the electrolyte. With this system, secondary metals can be readjusted without leave no anion in the bath. This system therefore extends the life of baths of the present invention.

Une autre voie pour introduire les métaux, toujours avec le même souci d'éviter de charger le bain en contre-ions consiste à les introduire sous forme de leurs hydroxydes.Another way to introduce metals, always with the same concern to avoid charging the bath with counter-ions consists in introducing them in the form of their hydroxides.

Les métaux secondaires pourront également être introduits sous forme de sulfate.Secondary metals can also be introduced in the form of sulfate.

D'une façon générale, les métaux secondaires seront avantageusement introduits sous forme de sulfates, de carbonates, d'hydroxydes ou de leurs mélanges.In general, the secondary metals will advantageously introduced in the form of sulfates, carbonates, hydroxides or their mixtures.

Ainsi, en évitant de préférence la présence de chlorures, les bains de l'invention permettent de prolonger la vie des équipements de galvanoplastie en évitant leur corrosion.Thus, preferably avoiding the presence of chlorides, the the invention make it possible to extend the life of electroplating equipment by avoiding their corrosion.

Selon un autre de ses aspects, l'invention concerne également un procédé d'électrodéposition du palladium ou d'un alliage de palladium, caractérisé en ce qu'il comprend l'électrolyse d'un bain électrolytique tel que défini précédemment en mettant en oeuvre des densités de courant comprises entre 0,5 et 150 A/dm2.According to another of its aspects, the invention also relates to a process for the electrodeposition of palladium or a palladium alloy, characterized in that it comprises the electrolysis of an electrolytic bath as defined above by implementing current densities between 0.5 and 150 A / dm 2 .

Le procédé de l'invention s'applique de façon particulièrement avantageuse dans les applications électroniques, où l'on cherche à travailler avec une vitesse de dépôt maximale et où les dépôts souhaités doivent être, entre autres, brillants, ductiles, non poreux. Pour obtenir de fortes productivités, les bains doivent fonctionner sous la densité de courant la plus élevée possible et une température et une agitation élevée sont souvent nécessaires. Les bains à base d'éthylènediamine autorisent des températures opératoires supérieures à celle pratiquée avec les bains ammoniacaux en butte aux émanations gazeuses générées.The process of the invention is particularly advantageous. in electronic applications, where we try to work with a speed of maximum deposit and where the desired deposits should be, among other things, brilliant, ductile, non-porous. To obtain high productivity, the baths must operate under the highest possible current density and temperature and high agitation is often necessary. Ethylene diamine baths allow operating temperatures higher than that practiced with baths ammonia exposed to the generated gaseous fumes.

L'utilisation des bains de l'invention, grâce à la présence conjointe de l'éthylènediamine comme agent complexant et de l'un des deux brillanteurs spécifiques de l'invention dans une gamme de pH de préférence comprise entre 3 et 5, permet d'étendre nettement la brillance dans les fortes et très fortes densités de courant. La densité de courant maximale accessible donnant des dépôts brillants est alors proportionnelle à la quantité de ce brillanteur.The use of the baths of the invention, thanks to the joint presence of ethylenediamine as a complexing agent and one of the two brighteners specific to the invention in a pH range preferably between 3 and 5, makes it possible to clearly extend the gloss in high and very high densities current. Maximum accessible current density giving deposits brilliants is then proportional to the quantity of this brilliance.

Le brillanteur spécifique de l'invention peut être utilisé dans des bains de palladium et d'alliages de palladium, où il est aussi très efficace, comme brillanteur à des fortes densités de courant et même à très faible concentration.The specific gloss of the invention can be used in baths of palladium and palladium alloys, where it's also very effective, like bright at high current densities and even at very low concentrations.

Dans leur version haute vitesse, les bains de l'invention admettent donc des densités de courant analogues, ou supérieures aux bains ammoniacaux les plus performants. Selon les applications, des dépôts brillants de 0,1 à 6 µm peuvent être réalisés à des densités de courant comprises entre 0,5 à 150 A/dm2.In their high speed version, the baths of the invention therefore admit current densities similar to, or greater than, the most efficient ammonia baths. Depending on the application, bright deposits of 0.1 to 6 µm can be produced at current densities between 0.5 to 150 A / dm 2 .

Toutefois les bains de l'invention peuvent également être utilisés à des vitesses et à des densités de courant moindres et, en particulier, dans des applications de décoration.However, the baths of the invention can also be used for lower speeds and densities of current and, in particular, in decoration applications.

Il n'y a pas de formation de sel insoluble sur les anodes de titane platiné. Cette particularité permet des applications en "jet plating", ainsi que des métallisations sélectives en continu, du type métallisation au tampon.There is no insoluble salt formation on the platinum titanium anodes. This feature allows "jet plating" applications, as well as continuous selective metallizations, of the pad metallization type.

Dans le procédé d'électrodéposition de l'invention, les anodes sont des anodes insolubles, de préférence en titane platiné, en platine recouvert d'oxyde d'iridium ou en métal précieux tel que le platine. Par ailleurs, la cathode est constituée d'un substrat métallisé.In the electrodeposition process of the invention, the anodes are insoluble anodes, preferably platinum titanium, oxide coated platinum iridium or a precious metal such as platinum. Furthermore, the cathode is made of a metallized substrate.

Les formulations préférées de bains selon la présente invention peuvent être de manière non restrictive décrites par la composition générale suivante dans laquelle les concentrations en dérivés métalliques (du palladium et éventuellement des métaux d'alliage) sont rapportées au métal et dans lesquelles le palladium est avantageusement introduit sous forme d'un composé de sulfate de palladium et d'éthylènediamine présentant des rapports molaires [SO4] : [Pd] = 0,9 à 1,15 et [Ethylènediamine] : [Pd] = 0,8 à 1,2 :

  • Palladium   1 à 100 g/l
  • Métal d'alliage choisi entre Ni, Co, Fe, In, Au, Ag,ou Sn   0 à 60 g/l
  • Ethylènediamine   2 à 200 ml/l
  • Acide 3-(3- pyridyl) acrylique   0,01 à 3 g/l ou acide 3-(3-quinolyl) acrylique
  • Sulfate de sodium   > 20 g/l
Les conditions opératoires sont avantageusement les suivantes :
  • pH   3 à 5
  • Température   10 à 75°C
  • Agitation   Modérée, à très vigoureuse
  • Densité de courant   0,5 à 150 A/dm2
  • Anode   Titane platiné
The preferred bath formulations according to the present invention can be non-restrictively described by the following general composition in which the concentrations of metallic derivatives (of palladium and optionally of alloying metals) are related to the metal and in which the palladium is advantageously introduced in the form of a compound of palladium sulfate and ethylenediamine having molar ratios [SO 4 ]: [Pd] = 0.9 to 1.15 and [Ethylenediamine]: [Pd] = 0.8 to 1, 2:
  • Palladium 1 to 100 g / l
  • Alloy metal chosen from Ni, Co, Fe, In, Au, Ag, or Sn 0 to 60 g / l
  • Ethylenediamine 2 to 200 ml / l
  • 3- (3-pyridyl) acrylic acid 0.01 to 3 g / l or 3- (3-quinolyl) acrylic acid
  • Sodium sulfate> 20 g / l
The operating conditions are advantageously as follows:
  • pH 3 to 5
  • Temperature 10 to 75 ° C
  • Moderate to very vigorous agitation
  • Current density 0.5 to 150 A / dm 2
  • Platinum Titanium Anode

EXEMPLESEXAMPLES

Dans les exemples les concentrations en palladium et métaux d'alliages sont rapportées au métal.In the examples, the concentrations of palladium and alloy metals are related to metal.

Les exemples qui suivent illustrent les bonnes performances des bains de l'invention.

  • a) Dans tous ces exemples, le substrat à métalliser, est préparé par une procédure convenable, selon la nature du métal. Par exemple, les substrats cuivreux, ou en nickel, sont préalablement dégraissés électrolytiquement, après un rinçage à l'eau, le substrat est dépassivé, dans de l'acide sulfurique dilué à 5 - 20% en volume, le substrat est rincé à l'aide d'eau désionisée, avant d'être immergé dans un des électrolytes de l'invention. De façon facultative, certains additifs peuvent être ajoutés. Ainsi :
    • Comme sel conducteur, on peut utiliser le sulfate de sodium, mais aussi le sulfate de potassium ou encore un mélange des deux sels.
    • Un tampon acétique, citrique, borique, ou tout autre système tampon efficace dans la gamme de pH concernée peut être utilisé pour stabiliser le pH du bain.
    • Un agent mouillant, peut être ajouté pour éviter les piqûres causées par le dégagement d'hydrogène sur les pièces. Un agent mouillant cationique, ou non ionique peut convenir, on pourra par exemple utiliser de l'iodure ou du bromure de cétyltriméthylammonium en très faibles quantités.
    • Un réducteur de tensions internes pourra être ajouté pour les applications décoratives, de très petites quantités de saccharinate de sodium peuvent être ajoutées, dans certains cas.
  • b) Le réajustement de la concentration en palladium est réalisé, par addition d'un composé ci-après désigné par A préparé selon la procédure suivante :
    • Matière première : une solution acide de nitrate de palladium.
    • Addition d'acide sulfurique dans un rapport molaire [H2SO4]/[Palladium] =1,0 à 1,7
    • Distillation d'un mélange eau+acide nitrique
    • Evaporation à sec
    • Redissolution dans l'eau du sulfate de palladium
    • Addition à une solution diluée d'éthylènediamine dans un rapport molaire [Ethylènediamine]:[Palladium] = 0,8 à 1,2
    • Temps de réaction sous agitation, à température ambiante.(> 12 h)
    • Filtration, séchage
    • The examples which follow illustrate the good performance of the baths of the invention.
  • a) In all of these examples, the substrate to be metallized is prepared by a suitable procedure, depending on the nature of the metal. For example, copper or nickel substrates are electrolytically degreased beforehand, after rinsing with water, the substrate is passivated, in sulfuric acid diluted to 5 - 20% by volume, the substrate is rinsed with water. using deionized water, before being immersed in one of the electrolytes of the invention. Optionally, some additives can be added. So :
    • As conductive salt, it is possible to use sodium sulphate, but also potassium sulphate or a mixture of the two salts.
    • An acetic, citric, boric buffer, or any other effective buffer system in the relevant pH range can be used to stabilize the pH of the bath.
    • A wetting agent can be added to prevent pitting caused by the evolution of hydrogen on the parts. A cationic or nonionic wetting agent may be suitable, it is possible for example to use iodide or cetyltrimethylammonium bromide in very small quantities.
    • An internal tension reducer can be added for decorative applications, very small amounts of sodium saccharinate can be added, in some cases.
  • b) The readjustment of the palladium concentration is carried out by adding a compound hereafter designated by A prepared according to the following procedure:
    • Raw material: an acid solution of palladium nitrate.
    • Addition of sulfuric acid in a molar ratio [H 2 SO 4 ] / [Palladium] = 1.0 to 1.7
    • Distillation of a water + nitric acid mixture
    • Dry evaporation
    • Redissolution in water of palladium sulfate
    • Addition to a dilute solution of ethylenediamine in a molar ratio [Ethylenediamine]: [Palladium] = 0.8 to 1.2
    • Reaction time with stirring, at room temperature. (> 12 h)
    • Filtration, drying

    • Le sel de teinte jaune, de sulfate de palladium et d'éthylènediamine contient approximativement 31 à 41% de palladium et présente des rapports molaires [SO4] : [Pd] = 0,9 à 1,15 et [Ethylènediamine] : [Pd] = 0,8 à 1,2 ci-après désigné par A.The yellow-tinted salt of palladium sulfate and ethylenediamine contains approximately 31 to 41% palladium and has molar ratios [SO 4 ]: [Pd] = 0.9 to 1.15 and [Ethylenediamine]: [Pd ] = 0.8 to 1.2 hereinafter designated by A.

    Cette méthode d'addition du palladium à l'électrolyte, peut être utilisée pour la première préparation du bain, et pour les réajustements palladium au cours du fonctionnement.This method of adding palladium to the electrolyte can be used for the first preparation of the bath, and for palladium readjustments during of operation.

    EXEMPLE 1 : Bain de palladium Haute vitesseEXAMPLE 1 High speed palladium bath

    • Palladium (introduit sous forme du composé A)   17 à 23 g/l
    • Nickel (sous forme de sulfate)   0,2 à 0,5 g/l
    • Ethylènediamine   55 à 75 ml/l
    • Acide Trans 3-(3-pyridyl) acrylique   0,22 à 0,38 g/l
    • Sulfate de sodium   20 à 50 g/l
       Conditions opératoires :
    • pH (Acide sulfurique / Hydroxyde de sodium)   3,5 à 4,5
    • Température   40 à 75°C
    • Agitation   Vigoureuse, à très vigoureuse
    • Densité de courant   5 à 42 A/dm2
    • Anode   Titane platiné
    • Palladium (introduced as compound A) 17 to 23 g / l
    • Nickel (as sulfate) 0.2 to 0.5 g / l
    • Ethylenediamine 55 to 75 ml / l
    • Trans 3- (3-pyridyl) acrylic acid 0.22 to 0.38 g / l
    • Sodium sulfate 20 to 50 g / l
    Operating conditions:
    • pH (Sulfuric acid / Sodium hydroxide) 3.5 to 4.5
    • Temperature 40 to 75 ° C
    • Vigorous, to very vigorous agitation
    • Current density 5 to 42 A / dm 2
    • Platinum Titanium Anode

    Ce bain dans lequel le nickel agit uniquement comme brillanteur, dépose du palladium à plus de 99,9%, le dépôt est brillant miroir, blanc, ductile, avec une faible résistivité, une faible porosité, et une bonne résistance à la corrosion.This bath in which the nickel acts only as a shine, deposits more than 99.9% palladium, the deposit is mirror-shiny, white, ductile, with a low resistivity, low porosity, and good corrosion resistance.

    EXEMPLE 2 : Bain de palladium-nickel Haute vitesseEXAMPLE 2 High speed palladium-nickel bath

    • Palladium (introduit sous forme du composé A)   17 à 23 g/l
    • Nickel (sous forme de sulfate)   9,0 à 13,0 g/l
    • Ethylènediamine   55 à 75 ml/l
    • Acide Trans 3-(3-pyridyl) acrylique   0,22 à 0,38 g/l
    • Sulfate de sodium   20 à 50 g/l
    Conditions opératoires :
    • pH (Acide sulfurique / Hydroxyde de sodium)   3,5 à 4,5
    • Température   60 à 75°C
    • Agitation   Vigoureuse, à très vigoureuse
    • Densité de courant   21 à 56 A/dm2
    • Anode   Titane platiné
    Les résultats moyens sont les suivants :
    • Vitesse de dépôt à 70°C et 28 A/dm2   1µm en 10 secondes
    • Vitesse de dépôt à 70°C et 42 A/dm2   1 µm en 7 secondes
    • Vitesse de dépôt à 70°C et 56 A/dm2   1 µm en 5 secondes
    • Rendement cathodique à 70°C et 56 A/dm2   87,2 %
    • Palladium (introduced as compound A) 17 to 23 g / l
    • Nickel (as sulphate) 9.0 to 13.0 g / l
    • Ethylenediamine 55 to 75 ml / l
    • Trans 3- (3-pyridyl) acrylic acid 0.22 to 0.38 g / l
    • Sodium sulfate 20 to 50 g / l
    Operating conditions:
    • pH (Sulfuric acid / Sodium hydroxide) 3.5 to 4.5
    • Temperature 60 to 75 ° C
    • Vigorous, to very vigorous agitation
    • Current density 21 to 56 A / dm 2
    • Platinum Titanium Anode
    The average results are as follows:
    • Deposition rate at 70 ° C and 28 A / dm 2 1µm in 10 seconds
    • Deposition rate at 70 ° C and 42 A / dm 2 1 µm in 7 seconds
    • Deposition rate at 70 ° C and 56 A / dm 2 1 µm in 5 seconds
    • Cathodic efficiency at 70 ° C and 56 A / dm 2 87.2%

    Ce bain dépose l'alliage palladium 80 % - nickel 20 %. Le dépôt de 0,1 à 6 µm est brillant-miroir, ductile, avec une faible résistance de contact, une dureté Vickers de 390 HV sous 100 gf (mesurée selon la norme iso 4 516 (1980)). Les dépôts contrôlés selon la norme iso 4524/3 (85), sont non poreux, ils ont une bonne résistance à la corrosion et, pour une épaisseur de 0,5 à 6 µm, ils sont conforme au test dit "CASS TEST" défini par la norme iso 9 227 (1990). Par ailleurs, ils ont une bonne résistance au frottement et passent positivement le test dit "BRITISH TELECOM".This bath deposits the 80% palladium - 20% nickel alloy. The deposit of 0.1 to 6 µm is mirror-gloss, ductile, with low contact resistance, hardness Vickers of 390 HV under 100 gf (measured according to ISO standard 4,516 (1980)). The deposits checked according to iso 4524/3 (85), are non-porous, they have a good corrosion resistance and, for a thickness of 0.5 to 6 µm, they are conforms to the so-called "CASS TEST" test defined by standard ISO 9 227 (1990). Through elsewhere, they have good resistance to friction and pass the test positively says "BRITISH TELECOM".

    EXEMPLE 3 : Bain de palladium-cobalt Haute vitesseEXAMPLE 3 High speed palladium-cobalt bath

    • Palladium (introduit sous forme du composé A)   17 à 23 g/l
    • Cobalt (sous forme de sulfate)   6,0 à 9,0 g/l
    • Ethylènediamine   55 à 75 ml/l
    • Acide Trans 3-(3-pyridyl) acrylique   0,22 à 0,38 g/l
    • Sulfate de sodium   20 à 50 g/l
    Conditions opératoires :
    • pH (Acide sulfurique/Hydroxyde de sodium)   3,5 à 4,5
    • Température   60 à 75°C
    • Agitation   Vigoureuse, à très vigoureuse
    • Densité de courant   21 à 56 A/dm2
    • Anode   Titane platiné
    • Palladium (introduced as compound A) 17 to 23 g / l
    • Cobalt (as sulfate) 6.0 to 9.0 g / l
    • Ethylenediamine 55 to 75 ml / l
    • Trans 3- (3-pyridyl) acrylic acid 0.22 to 0.38 g / l
    • Sodium sulfate 20 to 50 g / l
    Operating conditions:
    • pH (Sulfuric acid / Sodium hydroxide) 3.5 to 4.5
    • Temperature 60 to 75 ° C
    • Vigorous, to very vigorous agitation
    • Current density 21 to 56 A / dm 2
    • Platinum Titanium Anode

    Ce bain dépose l'alliage palladium 75 % - cobalt 25 %, le dépôt de 0,1 à 6 µm est brillant-miroir, ductile, avec une faible résistance de contact, dur. Les dépôts sont non poreux, ils ont une bonne résistance à la corrosion et au frottement.This bath deposits the palladium alloy 75% - cobalt 25%, the deposit from 0.1 to 6 µm is mirror-gloss, ductile, with low contact resistance, hard. The deposits are non-porous, they have good resistance to corrosion and friction.

    EXEMPLE 4 : Bain de palladium DécoratifEXAMPLE 4: Decorative Palladium Bath

    • Palladium (Introduit sous forme du composé A)   17 à 23 g/l
    • Nickel (sous forme de sulfate)   (de préférence 0,01 à 0,5 g/l)
    • Ethylènediamine   55 à 75 ml / l
    • Acide Trans 3-(3-pyridyl) acrylique   0,10 à 0,38 g/l
    • Sulfate de sodium   20 à 50 g/l
    Conditions opératoires :
    • pH (Acide sulfurique/Hydroxyde de sodium   3,5 à 4,5
    • Température   30 à 75°C
    • Agitation   Modérée
    • Densité de courant   0,5 à 5 A/dm2
    • Anode   Titane platiné
    • Palladium (Introduced in the form of compound A) 17 to 23 g / l
    • Nickel (as sulphate) (preferably 0.01 to 0.5 g / l)
    • Ethylenediamine 55 to 75 ml / l
    • Trans 3- (3-pyridyl) acrylic acid 0.10 to 0.38 g / l
    • Sodium sulfate 20 to 50 g / l
    Operating conditions:
    • pH (Sulfuric acid / Sodium hydroxide 3.5 to 4.5
    • Temperature 30 to 75 ° C
    • Moderate restlessness
    • Current density 0.5 to 5 A / dm 2
    • Platinum Titanium Anode

    Ce bain dans lequel le nickel agit uniquement comme brillanteur, dépose du palladium de pureté >99,9%. Le dépôt de 0,2 à 6 µm est brillant-miroir, blanc, ductile, sans craquelures. Les dépôts sont non poreux, ils ont une bonne résistance à la corrosion et au frottement.This bath in which the nickel acts only as a shine, deposits > 99.9% purity palladium. The 0.2 to 6 µm deposit is mirror-gloss, white, ductile, without cracks. The deposits are non-porous, they have good resistance corrosion and friction.

    EXEMPLE 5 : Bain de palladium-nickel décoratifEXAMPLE 5: Decorative palladium-nickel bath

    • Palladium (Introduit sous forme du composé A)   6 à 9 g/l
    • Nickel (sous forme de sulfate)   18,0 à 22,0g/l
    • Ethylènediamine   55 à 75 ml/l
    • Acide trans 3-(3-pyridyl) acrylique   0,02 à 0,15 g/l
    • Sulfate de sodium   20 à 50 g/l
    Conditions opératoires :
    • pH (Acide sulfurique/Hydroxyde de sodium)   3,5 à 4,5
    • Température   55 à 65°C
    • Agitation   Modérée
    • Densité de courant   1 à 5 A/dm2
    • Anode   Titane platiné
    • Palladium (Introduced in the form of compound A) 6 to 9 g / l
    • Nickel (as sulphate) 18.0 to 22.0 g / l
    • Ethylenediamine 55 to 75 ml / l
    • Trans 3- (3-pyridyl) acrylic acid 0.02 to 0.15 g / l
    • Sodium sulfate 20 to 50 g / l
    Operating conditions:
    • pH (Sulfuric acid / Sodium hydroxide) 3.5 to 4.5
    • Temperature 55 to 65 ° C
    • Moderate restlessness
    • Current density 1 to 5 A / dm 2
    • Platinum Titanium Anode

    Ce bain dépose l'alliage palladium 80% nickel 20%. Le dépôt de 0,2 à 6 µm est brillant-miroir, blanc, ductile, sans craquelures. Les dépôts sont non poreux, ils ont une bonne résistance à la corrosion et au frottement.This bath deposits the palladium alloy 80% nickel 20%. The deposit of 0.2 to 6 µm is mirror-gloss, white, ductile, without cracks. Deposits are no porous, they have good resistance to corrosion and friction.

    EXEMPLE 6 : Bain de palladium-cobalt décoratifEXAMPLE 6 Decorative palladium-cobalt bath

    • Palladium (introduit sous forme du composé A)   10 à 14 g/lPalladium (introduced as compound A) 10 to 14 g / l
    • Cobalt (sous forme de sulfate)   7,5 à 8,5 g/lCobalt (as sulfate) 7.5 to 8.5 g / l
    • Ethylènediamine   55 à 75 ml/lEthylenediamine 55 to 75 ml / l
    • Acide trans 3-(3-pyridyl) acrylique   0,02 à 0,15 g/lTrans 3- (3-pyridyl) acrylic acid 0.02 to 0.15 g / l
    • Sulfate de sodium   20 à 50 g/lSodium sulfate 20 to 50 g / l
    • Conditions opératoires :Operating conditions:
    • pH (Acide sulfurique/Hydroxyde de sodium)   3,5 à 4,5pH (Sulfuric acid / Sodium hydroxide) 3.5 to 4.5
    • Température   20 à 45°CTemperature 20 to 45 ° C
    • Agitation   ModéréeModerate agitation
    • Densité de courant   1 à 8 A/dm2 Current density 1 to 8 A / dm 2
    • Anode   Titane platinéPlatinum Titanium Anode

    Ce bain dépose l'alliage palladium 70 % - cobalt 30 % pour application décorative, le dépôt de 0,2 à 6 µm est brillant-miroir, ductile, sans craquelures. Les dépôts sont non poreux, ils ont une bonne résistance à la corrosion et au frottement.This bath deposits the palladium alloy 70% - cobalt 30% for application decorative, the deposit of 0.2 to 6 µm is shiny-mirror, ductile, without cracks. The deposits are non-porous, they have good resistance to corrosion and friction.

    Claims (17)

    1. Aqueous electrolysis bath of acidic pH for the electrochemical deposition of palladium or its alloys, said bath comprising a palladium compound and optionally at least one compound of a secondary metal to be codeposited in the form of an alloy with the palladium, and also comprising ethylenediamine as a palladium complexing agent, and an organic brightening agent, characterized in that said brightening agent is 3-(3-pyridyl)acrylic acid, 3-(3-quinolyl)acrylic acid or one of their salts, preferably one of their alkali metal salts.
    2. Electrolysis bath according to claim 1, characterized in that its pH is between 3 and 5.
    3. Electrolysis bath according to claim 1 or 2, characterized in that it contains at least one metal acting as an inorganic brightening agent.
    4. Electrolysis bath according to one of claims 1 to 3, characterized in that it contains from 1 to 100 g/l of palladium.
    5. Electrolysis bath according to one of claims 1 to 4, characterized in that it contains at least one secondary metal selected from the group consisting of nickel, cobalt, iron, indium, gold, silver and tin, at a concentration of between 0.1 and 60 g/l.
    6. Electrolysis bath according to one of claims 1 to 5, characterized in that it contains from 2 to 200 ml/l of ethylenediamine.
    7. Electrolysis bath according to one of claims 1 to 6, characterized in that it contains from 0.01 to 3 g/l of 3-(3-pyridyl)acrylic acid, 3-(3-quinolyl)acrylic acid or one of their salts.
    8. Electrolysis bath according to one of claims 1 to 7, characterized in that it contains at least 20 g/l of at least one conducting salt.
    9. Electrolysis bath according to claim 8, characterized in that said conducting salt is selected from the group consisting of sodium sulfate, potassium sulfate and mixtures thereof.
    10. Electrolysis bath according to one of claims 1 to 9, characterized in that it contains a buffer for stabilizing the pH, said buffer preferably being of the acetic, citric, boric, lactic, malic, phthalic, acrylic, tartaric, oxalic or succinic type.
    11. Electrolysis bath according to one of claims 1 to 10, characterized in that it contains at least one wetting agent, preferably cetyltrimethylammonium bromide or iodide.
    12. Electrolysis bath according to one of claims 1 to 11, characterized in that it contains an additive, preferably sodium saccharinate, for reducing the internal voltages of said deposit.
    13. Electrolysis bath according to one of claims 1 to 12, characterized in that the palladium is introduced in the form of the sulfate.
    14. Electrolysis bath according to one of claims 1 to 13, characterized in that the palladium is introduced in the form of a solid salt of palladium sulfate and ethylenediamine which comprises from 31 to 41 % of palladium and in which the molar ratio [SO4]:[Pd] is between 0.9 and 1.15 and the ratio [ethylenediamine]:[Pd] is between 0.8 and 1.2.
    15. Electrolysis bath according to one of claims 1 to 14, characterized in that it contains at least one secondary metal introduced into said bath in the form of the sulfate, carbonate or hydroxide or a mixture of these compounds.
    16. Process for the electroplating of palladium or a palladium alloy, characterized in that it comprises operating an electrolysis bath as defined in one of claims 1 to 15 by using current densities of between 0.5 and 150 A/dm2.
    17. Process according to claim 16, characterized in that said electrolysis is carried out using insoluble anodes preferably made of platinized titanium, platinum coated with iridium oxide, or a precious metal such as platinum, and a metallized substrate as the cathode.
    EP01921482A 2000-04-06 2001-04-05 Electrolytic solution for electrochemical deposit of palladium or its alloys Expired - Lifetime EP1272691B1 (en)

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    AU2001248465A1 (en) 2001-10-23
    JP4790191B2 (en) 2011-10-12
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    ES2220757T3 (en) 2004-12-16
    WO2001077417A1 (en) 2001-10-18
    FR2807450B1 (en) 2002-07-05
    DE60102364D1 (en) 2004-04-22
    JP2003530486A (en) 2003-10-14
    CN1190522C (en) 2005-02-23
    EP1272691A1 (en) 2003-01-08
    US6743346B2 (en) 2004-06-01
    DE60102364T2 (en) 2005-03-17
    FR2807450A1 (en) 2001-10-12
    ATE262055T1 (en) 2004-04-15

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