EP0423005A1 - Hydrazinbath for chemical plating platin and or palladium and process for preparing such a bath - Google Patents

Hydrazinbath for chemical plating platin and or palladium and process for preparing such a bath Download PDF

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Publication number
EP0423005A1
EP0423005A1 EP90402778A EP90402778A EP0423005A1 EP 0423005 A1 EP0423005 A1 EP 0423005A1 EP 90402778 A EP90402778 A EP 90402778A EP 90402778 A EP90402778 A EP 90402778A EP 0423005 A1 EP0423005 A1 EP 0423005A1
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Prior art keywords
bath
palladium
ethylenediamine
platinum
solution
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EP90402778A
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German (de)
French (fr)
Inventor
Pierre Josso
Serge Alperine
Pierre Steinmetz
Anne Costantini-Friant
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Office National dEtudes et de Recherches Aerospatiales ONERA
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Office National dEtudes et de Recherches Aerospatiales ONERA
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING 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
    • C23C—COATING 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
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • C23C18/42—Coating with noble metals
    • C23C18/44—Coating with noble metals using reducing agents

Definitions

  • the invention relates to the chemical deposition of platinum and / or palladium on a substrate, by autocatalytic reduction.
  • the industrial utility of a metal deposition bath depends to a large extent on the following three parameters: - absence of annoying impurities in the deposit; - Possibility of obtaining deposits with a thickness of several microns in a reasonable time, which implies both autocatalytic properties and a deposition rate of several microns per hour; - long bath life, preferably unlimited with periodic refills.
  • European Patent 0 227 518 in the name of the Applicant relating to a nickel and / or cobalt deposition bath, explains the advantage of choosing hydrazine as a reducing agent, which does not provide any impurity in the deposit.
  • This same patent also indicates that many anions, and in particular chloride, sulfate and nitrate anions, disturb the functioning of hydrazine baths.
  • US Patent No. 3,562,911 describes hydrazine baths for the chemical deposition of platinum, containing hexachloroplatinic acid and hydrochloric acid, and therefore chloride ions. These baths are not autocatalytic and operate until exhaustion without the reaction can be stopped. The platinum yield is at most 91%, that is to say that at least 9% of the platinum ions contained in the bath are lost.
  • the object of the invention is to provide a hydrazine autocatalytic bath, not containing chloride ions and which can be recharged to operate for long periods of time.
  • the subject of the invention is an aqueous bath for the chemical deposition of platinum and / or palladium, containing a compound of the metal or of each of the metals to be deposited and of hydrazine as reducing agent, characterized in that said compound is an oxalate and that the bath contains ethylenediamine as complexing agent and at least one stabilizer, this bath being strongly basic and having an autocatalytic action.
  • a bath according to the invention for the deposition of platinum advantageously contains platinum II at a concentration of between 0.05 and 0.15 g / l ion approximately, and a bath for the deposition of palladium, palladium at a concentration between 0.01 and 0.3 ion g / l approximately.
  • the invention also relates to a method for preparing a bath as defined above, in which a mother solution containing platinum II or palladium, ethylenediamine and oxalate anions is first prepared and therein then add the stabilizer (s) and hydrazine.
  • the platinum, ethylenediamine and oxalate concentrations and the pH of the stock solution are substantially the same as for the final bath.
  • the mother solution is concentrated, that is to say that the palladium ions, ethylenediamine and the oxalate anions are present there at higher concentrations than in the bath, and the stock solution is diluted and its pH possibly adjusted before introduction of the stabilizer and hydrazine.
  • a stock solution containing platinum, a stock solution containing palladium and dilution water are mixed in an amount suitable for obtaining the desired concentrations of platinum and palladium, and the stabilizer (s) and hydrazine are added.
  • Platinum II compounds and Platinum IV compounds are commercially available. The latter are much more stable and therefore easier to handle than the former. Their industrial use therefore leads to lower costs.
  • the most common platinum IV compounds are hexachloroplatinic acid H2PtCl6 and hexahydroxoplatinic acid H2Pt (OH) 6.
  • An intermediate complex is therefore formed with oxalate ions in an acid medium.
  • the acid medium suppresses the repulsive electrostatic effect with the amino ligand.
  • the platinum-ethylenediamine complex is obtained by neutralizing the acidic solution of platinum oxalate II by an excess of anhydrous ethylenediamine.
  • the pH can then be adjusted to a higher value by adding potassium hydroxide.
  • the manufacturing of the palladium stock solution uses palladium chloride PdCl2, which is the only compound practically available, as starting material.
  • This salt is soluble in an aqueous solution of hydrochloric acid.
  • a solution of potassium hydroxide in an amount sufficient to obtain a pH greater than 8 is added to the solution obtained, so as to precipitate the palladium in the form of hydroxide Pd (OH) 2, which is collected by filtration under vacuum.
  • This solution is neutralized by adding anhydrous ethylenediamine to a pH of about 10.
  • the mother solution is thus obtained in which the palladium is complexed with ethylenediamine.
  • This solution is concentrated and contains at least 0.1 gram ion of palladium, or at least 10 g / l of palladium metal.
  • the procedure for obtaining a palladium bath is as follows: - Diluted with deionized water, to the desired volume of bath, a volume of stock solution containing the desired amount of palladium ions. - We put in solution a primary stabilizer, for example arsenic pentoxide. - One or more secondary stabilizers chosen from imidazole, benzotriazole, copper sulphate, lead acetate, iodic acid and glycine are placed in solution. - The reducing agent (hydrated hydrazine) is added.
  • the mother solution obtained contains, for 1 liter, 0.1 gram ion of platinum, 1.2 mole of ethylenediamine and approximately 0.1 gram ion of oxalate.
  • a typical concentrated stock solution contains, for 1 liter, 0.1 to 0.2 gram ion of palladium and 0.1 to 0.19 gram ion of oxalate, its pH being between 9 and 12, depending on the quantities of reagent used and the final degree of concentration.
  • the ethylenediamine concentration is adjusted to 1M.
  • Example 1 To the stock solution of Example 1, the following constituents are added at the following concentrations: - primary stabilizer: arsenic pentoxide 6,5.10 ⁇ 4M - secondary stabilizer: imidazole 0.3M - reducing agent: hydrazine hydrate 1M
  • the pH of this bath is 13. It is used at 90 ° C. to coat an IN100 nickel-based alloy plate of dimensions approximate 10 mm x 13 mm x 2 mm. A constant deposition rate of 1 micron / hour is obtained for 2 hours, by recharging the bath periodically, after dosing, in a known manner. The deposit obtained is light gray and semi-gloss. Its surface appearance is dense and nodular, observations confirmed by metallographic examination on a polished section.
  • a bath is prepared having the following composition: Pt 0.1 ethylenediamine 3.1 oxaldate About 0.1 (remaining amount after precipitation) potassium hydroxide QSPP pH greater than 13 arsenic pentoxide 6.5 10 ⁇ 4 imidazole 0.5 hydrated hydrazine 4.1
  • the treated substrate is a Z10 NCD18-10 stainless steel plate previously nickel-plated and measuring approximately 20 mm x 20 mm x 2 mm. At a temperature of 82 ° C., a deposition rate of 1 micron / hour is obtained for 1 hour 40 minutes.
  • Example 2 From the stock solution of Example 2, a bath is prepared having the following composition in molarities: palladium 0.02 ethylenediamine 1.5 oxalate 0.19 arsenic pentoxide 10 ⁇ 3 imidazole 0.2 hydrazine 1 The pH of this bath is 10.5.
  • This bath is used to coat a nickel plate measuring approximately 10 mm x 10 mm x 2 mm at the temperature of 70 ° C. The speed obtained is 2 microns / hour for 1 hour.
  • the bath differs from the previous one in that the ethylenediamine concentration is 2M.
  • the concentration of ethylenediamine in the bath is brought to 3M, all other things being equal.
  • the deposition rate is 4 microns / hour for 1 hour.
  • the bath is similar to the previous ones, the ethylenediamine concentration being brought to 4M.
  • the deposition rate at 70 ° C goes to 5 microns / hour for 1 hour.
  • Example 5 A bath similar to that of Example 5 is prepared, except with regard to the imidazole concentration which is 0.3M.
  • the bath differs from those of Examples 1 and 9 by an imidazole concentration of 0.4M.
  • the concentration of imidazole in the bath is brought to 0.5M, without any other change.
  • the deposition rate increases to 4.5 microns / hour for 2 hours.
  • Example 2 From the stock solution of Example 2, a bath is prepared having the following composition, in molarities: palladium 0.1 ethylenediamine 3 oxalate 0.5 arsenic pentoxide 10 ⁇ 3 imidazole 0.4 hydrazine 1 Its pH is equal to 9.
  • the bath differs from that of Example 12 by replacing the arsenic pentoxide with copper sulphate at a concentration of 1.7.10 ⁇ 4M, the pH being equal to 9.5.
  • the bath differs from that of Example 12 by replacing the arsenic pentoxide with potassium iodate at the same concentration, the pH here again being equal to 9.5.
  • the bath differs from that of the previous example in that the potassium iodate concentration is reduced to 10 ⁇ 4M.
  • a deposition rate of 2.5 microns / hour for 10 hours is observed under the usual conditions of use.
  • the bath differs from those of the two previous examples in that the potassium iodate concentration is reduced to 10 ⁇ 5M.
  • the same bath at a temperature of 60 ° C provided a deposition rate of 1.5 microns / hour for 3 hours.
  • a bath is prepared having the following composition, in molarities: palladium 0.19 ethylenediamine 1 oxalate 0.19 arsenic pentoxide 6.5.10 ⁇ 4 imidazole 0.3 hydrazine 0.14 the pH being brought to a value greater than or equal to 13 by potassium hydroxide.
  • This bath can be used in a temperature range from 75 to 90 ° C, the deposition rate varying between 4 and 25 microns / hour.
  • the deposit obtained, whose growth is of the columnar type, has a very healthy surface appearance and slightly cracked in its external part (rapid growth deposit).
  • the bath of Example 16 is used to coat a plate te silicon carbide ceramic measuring approximately 10 mm x 8 mm x 3 mm having previously undergone an appropriate surface treatment.
  • this surface treatment comprises the following stages: a) chemical degreasing for 10 min in a solution having the following composition, at 90 ° C: sodium hydroxide 120 g / l trisodium phosphate 100 g / l sodium perborate NaBO2.H2O2.H2O 50 g / l wetting agent (Teepol type) 100 ml / l b) After careful rinsing with deionized water, immersion in a hydrochloric solution containing 5 g / l of palladium chloride, for 10 to 15 minutes. c) Rinsing again with deionized water then immersion in pure hydrated hydrazine for 3 to 5 minutes. d) Rinsing again with deionized water.
  • the wafer is then introduced into the bath according to the invention and the deposition reaction starts as soon as its surface temperature reaches that of the bath.
  • a deposition rate of 4.5 microns / hour is obtained for 2 hours.
  • the deposit is healthy and adherent.
  • a bath is prepared having the following composition, in molarities: palladium 0.03 platinum II 0.06 ethylenediamine 2.7 oxalate 0.2 arsenic pentoxide 10 ⁇ 3 imidazole 0.4 hydrazine 1
  • the pH of this bath is equal to 10.5. Under the conditions of use of Examples 5 to 15, a deposition rate of 3 microns / hour for 1 hour is obtained. Analysis of the deposit shows that it is an alloy composed of 80% palladium and 20% platinum by mass.
  • the baths according to the invention have a practically unlimited lifetime with periodic recharging.
  • Tables 1 and 2 indicate the ranges of compositions and conditions of use of the platinum and palladium baths respectively.
  • the load of the bath is the ratio between the surface to be coated and the volume of the bath.
  • the minimum and maximum columns indicate the limit values.
  • the "optimal" column indicates the preferred value or range of values for each parameter.
  • the stability of the baths according to the invention makes it possible to introduce therein particles to be included in the deposits, as described in the aforementioned Patent No. 2,590,595.
  • These particles (ceramic such as alumina or yttrine, metal or alloy) are obtained by grinding in the presence of the mother solution and a deflocculant.

Abstract

Bath containing an oxalate of the metal or of each of the metals to be deposited and hydrazine as reducing agent, as well as ethylenediamine as complexing agent and at least one stabiliser, this bath being strongly basic and having an autocatalytic action.

Description

L'invention concerne le dépôt chimique de platine et/ou de palladium sur un substrat, par réduction autocatalytique.The invention relates to the chemical deposition of platinum and / or palladium on a substrate, by autocatalytic reduction.

L'utilité industrielle d'un bain de dépôt de métal dépend dans une large mesure des trois paramètres suivants :
- absence d'impuretés gênantes dans le dépôt;
- possibilité d'obtenir des dépôts d'une épaisseur de plusieurs microns en un temps raisonnable, ce qui implique à la fois des propriétés autocatalytiques et une vitesse de dépôt de plusieurs microns par heure;
- durée de vie du bain élevée, de préférence illimitée avec recharges périodiques.The industrial utility of a metal deposition bath depends to a large extent on the following three parameters:
- absence of annoying impurities in the deposit;
- Possibility of obtaining deposits with a thickness of several microns in a reasonable time, which implies both autocatalytic properties and a deposition rate of several microns per hour;
- long bath life, preferably unlimited with periodic refills.

En ce qui concerne le premier point, le Brevet Européen 0 227 518 au nom du Demandeur, relatif à un bain de dépôt de nickel et/ou de cobalt, expose l'intérêt de choisir comme réducteur l'hydrazine, qui n'apporte aucune impureté dans le dépôt. Ce même Brevet indique également que de nombreux anions, et en particulier les anions chlorure, sulfate et nitrate, perturbent le fonctionnement des bains à l'hydrazine.With regard to the first point, European Patent 0 227 518 in the name of the Applicant, relating to a nickel and / or cobalt deposition bath, explains the advantage of choosing hydrazine as a reducing agent, which does not provide any impurity in the deposit. This same patent also indicates that many anions, and in particular chloride, sulfate and nitrate anions, disturb the functioning of hydrazine baths.

Le Brevet US No 3 562 911 décrit des bains à l'hydrazine pour le dépôt chimique de platine, contenant de l'acide hexachloroplatinique et de l'acide chlorhydrique, et par conséquent des ions chlorure. Ces bains ne sont pas auto­catalytiques et fonctionnent jusqu'à épuisement sans que la réaction puisse être interrompue. Le rendement en platine est au maximum de 91%, c'est-à-dire que 9% au moins des ions platine contenus dans le bain sont perdus.US Patent No. 3,562,911 describes hydrazine baths for the chemical deposition of platinum, containing hexachloroplatinic acid and hydrochloric acid, and therefore chloride ions. These baths are not autocatalytic and operate until exhaustion without the reaction can be stopped. The platinum yield is at most 91%, that is to say that at least 9% of the platinum ions contained in the bath are lost.

Le but de l'invention est de proposer un bain autocatalyti­que à l'hydrazine, ne contenant pas d'ions chlorure et pouvant être rechargé pour fonctionner pendant de longues durées.The object of the invention is to provide a hydrazine autocatalytic bath, not containing chloride ions and which can be recharged to operate for long periods of time.

L'invention a pour objet un bain aqueux pour le dépôt chimique de platine et/ou de palladium, contenant un composé du métal ou de chacun des métaux à déposer et de l'hydrazine comme réducteur, caractérisé en ce que ledit composé est un oxalate et que le bain contient de l'éthylènediamine comme complexant et au moins un stabilisant, ce bain étant fortement basique et ayant une action autocatalytique.The subject of the invention is an aqueous bath for the chemical deposition of platinum and / or palladium, containing a compound of the metal or of each of the metals to be deposited and of hydrazine as reducing agent, characterized in that said compound is an oxalate and that the bath contains ethylenediamine as complexing agent and at least one stabilizer, this bath being strongly basic and having an autocatalytic action.

Un bain selon l'invention pour le dépôt de platine contient avantageusement du platine II à une concentration comprise entre 0,05 et 0,15 ion g/l environ, et un bain pour le dépôt de palladium, du palladium à une concentration compri­se entre 0,01 et 0,3 ion g/l environ.A bath according to the invention for the deposition of platinum advantageously contains platinum II at a concentration of between 0.05 and 0.15 g / l ion approximately, and a bath for the deposition of palladium, palladium at a concentration between 0.01 and 0.3 ion g / l approximately.

L'invention vise également un procédé de préparation d'un bain tel que défini ci-dessus, dans lequel on prépare d'abord une solution-mère contenant du platine II ou du palladium, de l'éthylènediamine et des anions oxalate et on y ajoute ensuite le ou les stabilisant(s) et l'hy­drazine.The invention also relates to a method for preparing a bath as defined above, in which a mother solution containing platinum II or palladium, ethylenediamine and oxalate anions is first prepared and therein then add the stabilizer (s) and hydrazine.

Dans le cas d'un bain au platine, les concentrations en platine, en éthylènediamine et en oxalate et le pH de la solution-mère sont sensiblement les mêmes que pour le bain final. Dans le cas d'un bain au palladium, la solution-mère est concentrée, c'est-à-dire que les ions palladium, l'éthylènediamine et les anions oxalate y sont présents à des concentrations plus élevées que dans le bain, et la solution-mère est diluée et son pH éventuelle­ment ajusté avant introduction du stabilisant et de l'hy­drazine.In the case of a platinum bath, the platinum, ethylenediamine and oxalate concentrations and the pH of the stock solution are substantially the same as for the final bath. In the case of a palladium bath, the mother solution is concentrated, that is to say that the palladium ions, ethylenediamine and the oxalate anions are present there at higher concentrations than in the bath, and the stock solution is diluted and its pH possibly adjusted before introduction of the stabilizer and hydrazine.

Dans le cas d'un bain pour le dépôt simultané de platine et de palladium, on mélange une solution-mère contenant du platine, une solution-mère contenant du palladium et de l'eau de dilution en quantité convenable pour obtenir les concentrations voulues en platine et en palladium, et on ajoute le ou les stabilisant(s) et l'hydrazine.In the case of a bath for the simultaneous deposition of platinum and palladium, a stock solution containing platinum, a stock solution containing palladium and dilution water are mixed in an amount suitable for obtaining the desired concentrations of platinum and palladium, and the stabilizer (s) and hydrazine are added.

On décrit maintenant la fabrication d'une solution-mère de platine.We now describe the manufacture of a platinum stock solution.

On trouve dans le commerce des composés de platine II et des composés de platine IV. Ces derniers sont beaucoup plus stables et par conséquent plus aisés à manipuler que les premiers. Leur utilisation industrielle conduit donc à des coûts moins élevés. Les composés de platine IV les plus courants sont l'acide hexachloroplatinique H₂PtCl₆ et l'acide hexahydroxoplatinique H₂Pt(OH)₆.Platinum II compounds and Platinum IV compounds are commercially available. The latter are much more stable and therefore easier to handle than the former. Their industrial use therefore leads to lower costs. The most common platinum IV compounds are hexachloroplatinic acid H₂PtCl₆ and hexahydroxoplatinic acid H₂Pt (OH) ₆.

C'est ce dernier composé qu'on choisit comme produit de départ, pour éviter la présence des anions chlorure en raison de leur influence néfaste sur l'oxydation de l'hydra­zine.It is this latter compound that is chosen as starting material, to avoid the presence of chloride anions because of their harmful influence on the oxidation of hydrazine.

En milieu basique, en présence d'une solution d'hydroxyde de potassium, l'acide hexahydroxoplatinique forme des anions hexahydroxoplatinate Pt(OH)₆²⁻, dans lesquels les ions Pt⁴⁺ sont complexés par les anions OH⁻ avec une force insuffisante pour assurer la stabilité du sel vis-à-vis du réducteur constitué par l'hydrazine. On souhaite donc remplacer le ligand OH⁻ par un ligand aminé formant un complexe plus stable. Mais l'expérience montre que ce remplacement n'est pas possible directement en raison de l'encombrement des ions OH⁻ et des ligands aminés, et de l'effet électrostatique répulsif entre la charge négative des anions OH⁻ et le doublet électronique de l'azote.In basic medium, in the presence of a potassium hydroxide solution, hexahydroxoplatinic acid forms hexahydroxoplatinate anions Pt (OH) ₆²⁻, in which the Pt⁴⁺ ions are complexed by the OH⁻ anions with an insufficient force to ensure the stability of the salt with respect to the reducing agent constituted by hydrazine. We therefore wish to replace the OH⁻ ligand with an amino ligand forming a more stable complex. However, experience shows that this replacement is not possible directly due to the bulk of the OH⁻ ions and amino ligands, and the electrostatic repulsive effect between the negative charge of the OH⁻ anions and the electronic doublet of the 'nitrogen.

On forme donc un complexe intermédiaire avec des ions oxalate en milieu acide. Le milieu acide supprime l'effet électrostatique répulsif avec le ligand aminé.An intermediate complex is therefore formed with oxalate ions in an acid medium. The acid medium suppresses the repulsive electrostatic effect with the amino ligand.

Pour ce faire, on ajoute à la solution d'hexahydroxoplati­nate de potassium une quantité d'acide oxalique solide suffisante pour obtenir un pH acide, par exemple de l'ordre de 2 :
Pt(OH)₆²⁻ + 3 H₂C₂O₄ -> Pt(C₂O₄)₂ + C₂O₄²⁻ + 6 H₂OTo do this, a quantity of solid oxalic acid sufficient to obtain an acidic pH, for example of the order of 2, is added to the potassium hexahydroxoplatinate solution:
Pt (OH) ₆²⁻ + 3 H₂C₂O₄ -> Pt (C₂O₄) ₂ + C₂O₄²⁻ + 6 H₂O

A ce stade, la solution est de couleur verte. Après quelques heures de repos, on constate un dégagement de gaz carbonique et la solution devient bleu sombre. Les ions oxalate ont réduit le platine IV au degré d'oxydation II selon la réaction :
Pt(C₂O₄)₃²⁻ -> 2 CO₂ + Pt(C₂O₄)₂²⁻At this point, the solution is green in color. After a few hours of rest, there is a release of carbon dioxide and the solution becomes dark blue. The oxalate ions reduced platinum IV to the degree of oxidation II depending on the reaction:
Pt (C₂O₄) ₃²⁻ -> 2 CO₂ + Pt (C₂O₄) ₂²⁻

La limitation de la réduction à l'état II et non à l'état métallique est due au fait que le platine est présent sous forme complexée, plus difficile à réduire.The limitation of the reduction to state II and not to the metallic state is due to the fact that the platinum is present in complexed form, which is more difficult to reduce.

Cette réduction préalable du platine est favorable, car elle diminue la quantité d'hydrazine nécessaire pour la réduction à l'état métallique.This prior reduction of platinum is favorable because it reduces the amount of hydrazine required for reduction in the metallic state.

Le complexe platine-éthylènediamine est obtenu en neutrali­sant la solution acide d'oxalate de platine II par un excès d'éthylènediamine anhydre. Cette dibase faible (pK₁ = 6,9, pK₂ = 10,0) amène le pH à une valeur comprise entre 8 et 10 lorsqu'elle est mise en oeuvre à raison d'au moins 4 moles d'éthylènediamine pour un ion gramme de platine II, ce qui correspond au double de la quantité stoechiomé­trique nécessaire pour former le complexe de coordinance II. On peut ensuite ajuster le pH à une valeur supérieure par addition d'hydroxyde de potassium.The platinum-ethylenediamine complex is obtained by neutralizing the acidic solution of platinum oxalate II by an excess of anhydrous ethylenediamine. This weak dibase (pK₁ = 6.9, pK₂ = 10.0) brings the pH to a value between 8 and 10 when it is used at the rate of at least 4 moles of ethylenediamine for one gram ion of platinum II, which corresponds to twice the stoichiometric quantity necessary to form the coordination complex II. The pH can then be adjusted to a higher value by adding potassium hydroxide.

La fabrication de la solution-mère de palladium utilise comme produit de départ le chlorure de palladium PdCl₂, qui est le seul composé pratiquement disponible.The manufacturing of the palladium stock solution uses palladium chloride PdCl₂, which is the only compound practically available, as starting material.

Ce sel est soluble dans une solution aqueuse d'acide chlor­hydrique.This salt is soluble in an aqueous solution of hydrochloric acid.

On ajoute à la solution obtenue une solution d'hydroxyde de potassium en quantité suffisante pour obtenir un pH supérieur à 8, de façon à précipiter le palladium sous forme d'hydroxyde Pd(OH)₂, qu'on recueille par filtration sous dépression.A solution of potassium hydroxide in an amount sufficient to obtain a pH greater than 8 is added to the solution obtained, so as to precipitate the palladium in the form of hydroxide Pd (OH) ₂, which is collected by filtration under vacuum.

On met alors en solution l'hydroxyde de palladium, de couleur marron foncé, dans une solution d'acide oxalique, et on obtient une solution de couleur brun rouge foncé dont le pH est compris entre 1 et 2.Palladium hydroxide, of dark brown color, is then dissolved in an oxalic acid solution, and a solution of dark red brown color is obtained whose pH is between 1 and 2.

On neutralise cette solution par addition d'éthylènediamine anhydre jusqu'à un pH de 10 environ. On obtient ainsi la solution-mère dans laquelle le palladium est complexé par l'éthylènediamine. Cette solution est concentrée et contient au moins 0,1 ion gramme de palladium, soit au moins 10 g/l de palladium métal.This solution is neutralized by adding anhydrous ethylenediamine to a pH of about 10. The mother solution is thus obtained in which the palladium is complexed with ethylenediamine. This solution is concentrated and contains at least 0.1 gram ion of palladium, or at least 10 g / l of palladium metal.

Pour obtenir un bain de platinage, on procède comme suit :
- On part d'une quantité de solution-mère égale au volume de bain désiré.
- On met en solution un stabilisant primaire tel que le pentoxyde d'arsenic.
- On met en solution un ou plusieurs stabilisants secondai­res choisis parmi l'imidazole, le benzotriazole, le sulfate de cuivre, l'acétate de plomb, l'acide iodique et le gly­cocolle.To obtain a platinum bath, we proceed as follows:
- We start with an amount of stock solution equal to the desired volume of bath.
- We put in solution a primary stabilizer such as arsenic pentoxide.
- One or more secondary stabilizers chosen from imidazole, benzotriazole, copper sulphate, lead acetate, iodic acid and glycine are placed in solution.

Après mise en température, le bain est prêt à l'emploi.After warming up, the bath is ready for use.

La procédure d'obtention d'un bain de palladiage est la suivante :
- On dilue à l'eau désionisée, au volume de bain désiré, un volume de solution-mère contenant la quantité d'ions palladium voulue.
- On met en solution un stabilisant primaire, par exemple le pentoxyde d'arsenic.
- On met en solution un ou plusieurs stabilisants secondai­res choisis parmi l'imidazole, le benzotriazole, le sulfate de cuivre, l'acétate de plomb, l'acide iodique et le gly­cocolle.
- On ajoute le réducteur (hydrazine hydratée).The procedure for obtaining a palladium bath is as follows:
- Diluted with deionized water, to the desired volume of bath, a volume of stock solution containing the desired amount of palladium ions.
- We put in solution a primary stabilizer, for example arsenic pentoxide.
- One or more secondary stabilizers chosen from imidazole, benzotriazole, copper sulphate, lead acetate, iodic acid and glycine are placed in solution.
- The reducing agent (hydrated hydrazine) is added.

Après mise en température, le bain est prêt à l'emploi.After warming up, the bath is ready for use.

Exemple 1 : Préparation d'une solution-mère de platineEXAMPLE 1 Preparation of a Platinum Stock Solution

Pour obtenir 1 litre de solution-mère, on procède comme suit :
- on dissout 1 mole d'hydroxyde de potassium dans 0,5 l d'eau désionisée;
- on ajoute 0,1 mole d'acide hexahydroxoplatinique, et on obtient une solution de couleur brun rouge;
- on ajoute 4 moles d'acide oxalique et environ 1 l d'eau désionisée; la solution devient beige;
- on chauffe à 50°C pour achever la dissolution des cristaux d'acide oxalique et la neutralisation de l'hexahydroxo­platinate; la solution prend une teinte verte;
- après 16 heures de repos, la solution est devenue bleu foncé par suite de la réduction du platine IV en platine II;
- on ajoute 1,2 mole d'éthylènediamine anhydre; la solution devient jaune foncé;
- on chauffe à 90°C pour réduire le volume à 1 litre et on filtre pour obtenir une solution limpide de pH 8;
- on ajoute de l'hydroxyde de potassium jusqu'à pH 13, et on filtre la solution pour éliminer le précipité d'oxala­te de potassium.To obtain 1 liter of stock solution, proceed as follows:
- 1 mole of potassium hydroxide is dissolved in 0.5 l of deionized water;
- 0.1 mol of hexahydroxoplatinic acid is added, and a red-brown solution is obtained;
- 4 moles of oxalic acid and approximately 1 l of deionized water are added; the solution becomes beige;
- heated to 50 ° C to complete the dissolution of the crystals oxalic acid and the neutralization of hexahydroxoplatinate; the solution turns green;
- after 16 hours of rest, the solution became dark blue due to the reduction of platinum IV to platinum II;
- 1.2 moles of anhydrous ethylenediamine are added; the solution becomes dark yellow;
- heated to 90 ° C to reduce the volume to 1 liter and filtered to obtain a clear solution of pH 8;
- Add potassium hydroxide to pH 13, and filter the solution to remove the precipitate of potassium oxalate.

La solution-mère obtenue contient, pour 1 litre, 0,1 ion gramme de platine, 1,2 mole d'éthylènediamine et environ 0,1 ion gramme d'oxalate.The mother solution obtained contains, for 1 liter, 0.1 gram ion of platinum, 1.2 mole of ethylenediamine and approximately 0.1 gram ion of oxalate.

Il n'est pas possible de préparer une solution sensiblement plus concentrée sans risquer qu'elle soit instable et conduise à la précipitation de sels de platine.It is not possible to prepare a substantially more concentrated solution without risking it being unstable and leading to precipitation of platinum salts.

Exemple 2 : Préparation d'une solution-mère de palladiumExample 2: Preparation of a stock solution of palladium

On procède comme suit :
- on ajoute à 0,18 litre d'eau désionisée 0,17 litre d'acide chlorhydrique à 37% pour obtenir 0,35 litre d'une solution d'acide chlorhydrique 5M;
- on ajoute 35 g de chlorure de palladium, et on obtient une solution limpide de couleur brun rouge et de pH 0;
- par ailleurs, on prépare une solution d'hydroxyde de potassium 7,5M;
- on neutralise la solution de chlorure de palladium par cette solution d'hydroxyde de potassium, pour obtenir un précipité d'hydroxyde de palladium qu'on recueille par filtration sous dépression sur un verre fritté N°3, avec lavage à l'aide de la même solution d'hydroxyde de potassium;
- on met en solution l'hydroxyde de palladium dans une solution molaire d'acide oxalique;
- on ajoute de l'éthylènediamine jusqu'à obtention d'un pH supérieur ou égal à 9.We proceed as follows:
- 0.17 liter of deionized water is added 0.17 liter of 37% hydrochloric acid to obtain 0.35 liter of a 5M hydrochloric acid solution;
- 35 g of palladium chloride are added, and a clear reddish brown solution of pH 0 is obtained;
- in addition, a hydroxide solution is prepared 7.5M potassium;
- The palladium chloride solution is neutralized with this potassium hydroxide solution, to obtain a palladium hydroxide precipitate which is collected by filtration under vacuum on a No. 3 sintered glass, with washing using the same potassium hydroxide solution;
- The palladium hydroxide is dissolved in a molar solution of oxalic acid;
- Ethylenediamine is added until a pH greater than or equal to 9 is obtained.

Cette solution peut être conservée telle quelle ou concen­trée. Une solution-mère concentrée typique contient, pour 1 litre, 0,1 à 0,2 ion gramme de palladium et 0,1 à 0,19 ion gramme d'oxalate, son pH étant compris entre 9 et 12, selon les quantités de réactif utilisées et le degré de concentration final. La concentration en éthylènediamine est ajustée à 1M.This solution can be kept as it is or concentrated. A typical concentrated stock solution contains, for 1 liter, 0.1 to 0.2 gram ion of palladium and 0.1 to 0.19 gram ion of oxalate, its pH being between 9 and 12, depending on the quantities of reagent used and the final degree of concentration. The ethylenediamine concentration is adjusted to 1M.

Exemples 3 et 4 : Bains de platineExamples 3 and 4: Platinum baths Exemple 3Example 3

A la solution-mère de l'exemple 1 on ajoute les constituants suivants aux concentrations suivantes :
- stabilisant primaire : pentoxyde d'arsenic 6,5.10⁻⁴M
- stabilisant secondaire : imidazole 0,3M
- réducteur : hydrazine hydratée 1MTo the stock solution of Example 1, the following constituents are added at the following concentrations:
- primary stabilizer: arsenic pentoxide 6,5.10⁻⁴M
- secondary stabilizer: imidazole 0.3M
- reducing agent: hydrazine hydrate 1M

Le pH de ce bain est de 13. On l'utilise à 90°C pour revêtir une plaquette d'alliage IN100 à base de nickel de dimensions approximatives 10 mm x 13 mm x 2 mm. On obtient pendant 2 heures une vitesse de dépôt constante de 1 micron/heure, en rechargeant le bain périodiquement, après dosage, de façon connue. Le dépôt obtenu est gris clair et semi-­brillant. Son aspect de surface est dense et nodulaire, observations confirmées par l'examen métallographique sur coupe polie.The pH of this bath is 13. It is used at 90 ° C. to coat an IN100 nickel-based alloy plate of dimensions approximate 10 mm x 13 mm x 2 mm. A constant deposition rate of 1 micron / hour is obtained for 2 hours, by recharging the bath periodically, after dosing, in a known manner. The deposit obtained is light gray and semi-gloss. Its surface appearance is dense and nodular, observations confirmed by metallographic examination on a polished section.

Exemple 4Example 4

A partir de la solution-mère de l'exemple 1, on prépare un bain ayant la composition suivante : Pt 0,1 éthylènediamine 3,1 oxaldate 0,1 environ (quantité restante après précipitation) hydroxyde de potassium QSPP pH supérieur à 13 pentoxyde d'arsenic 6,5 10⁻⁴ imidazole 0,5 hydrazine hydratée 4,1 From the stock solution of Example 1, a bath is prepared having the following composition: Pt 0.1 ethylenediamine 3.1 oxaldate About 0.1 (remaining amount after precipitation) potassium hydroxide QSPP pH greater than 13 arsenic pentoxide 6.5 10⁻⁴ imidazole 0.5 hydrated hydrazine 4.1

Le susbtrat traité est une plaquette d'acier inoxydable Z10 NCD18-10 préalablement nickelée et mesurant approximative­ment 20 mm x 20 mm x 2 mm. A la température de 82°C on obtient une vitesse de dépôt de 1 micron/heure pendant 1 heure 40.The treated substrate is a Z10 NCD18-10 stainless steel plate previously nickel-plated and measuring approximately 20 mm x 20 mm x 2 mm. At a temperature of 82 ° C., a deposition rate of 1 micron / hour is obtained for 1 hour 40 minutes.

Exemples 5-18 : Bains de palladiumExamples 5-18: Palladium baths Exemple 5Example 5

A partir de la solution-mère de l'exemple 2, on prépare un bain ayant la composition suivante en molarités : palladium 0,02 éthylènediamine 1,5 oxalate 0,19 pentoxyde d'arsenic 10⁻³ imidazole 0,2 hydrazine 1 Le pH de ce bain est de 10,5. From the stock solution of Example 2, a bath is prepared having the following composition in molarities: palladium 0.02 ethylenediamine 1.5 oxalate 0.19 arsenic pentoxide 10⁻³ imidazole 0.2 hydrazine 1 The pH of this bath is 10.5.

On utilise ce bain pour revêtir une plaquette de nickel mesurant approximativement 10 mm x 10 mm x 2 mm à la tempé­rature de 70°C. La vitesse obtenue est de 2 microns/heure pendant 1 heure.This bath is used to coat a nickel plate measuring approximately 10 mm x 10 mm x 2 mm at the temperature of 70 ° C. The speed obtained is 2 microns / hour for 1 hour.

Exemple 6Example 6

Le bain diffère du précédent en ce que la concentration en éthylènediamine est 2M.The bath differs from the previous one in that the ethylenediamine concentration is 2M.

Dans les mêmes conditions d'utilisation, on obtient une vitesse de dépôt de 3 microns/heure pendant 1 heure.Under the same conditions of use, a deposition rate of 3 microns / hour for 1 hour is obtained.

Exemple 7Example 7

La concentration du bain en éthylènediamine est portée à 3M, toutes choses égales par ailleurs.The concentration of ethylenediamine in the bath is brought to 3M, all other things being equal.

La vitesse de dépôt est de 4 microns/heure pendant 1 heure.The deposition rate is 4 microns / hour for 1 hour.

Exemple 8Example 8

Le bain est semblable aux précédents, la concentration en éthylènediamine étant portée à 4M.The bath is similar to the previous ones, the ethylenediamine concentration being brought to 4M.

La vitesse de dépôt à 70°C passe à 5 microns/heure pendant 1 heure.The deposition rate at 70 ° C goes to 5 microns / hour for 1 hour.

Exemple 9Example 9

On prépare un bain semblable à celui de l'exemple 5, sauf en ce qui concerne la concentration en imidazole qui est 0,3M.A bath similar to that of Example 5 is prepared, except with regard to the imidazole concentration which is 0.3M.

Dans les mêmes conditions d'utilisation, on obtient une vitesse de dépôt de 6 microns/heure pendant 4 heures.Under the same conditions of use, a deposition rate of 6 microns / hour for 4 hours is obtained.

Exemple 10Example 10

Le bain diffère de ceux des exemples 1 et 9 par une concen­tration en imidazole de 0,4M.The bath differs from those of Examples 1 and 9 by an imidazole concentration of 0.4M.

Toutes choses égales par ailleurs, on obtient une vitesse de dépôt de 6 microns/heure pendant 5 heures.All other things being equal, a deposition rate of 6 microns / hour is obtained for 5 hours.

Exemple 11Example 11

La concentration du bain en imidazole est portée à 0,5M, sans autre changement.The concentration of imidazole in the bath is brought to 0.5M, without any other change.

La vitesse de dépôt passe à 4,5 microns/heure pendant 2 heures.The deposition rate increases to 4.5 microns / hour for 2 hours.

Exemple 12Example 12

A partir de la solution-mère de l'exemple 2, on prépare un bain ayant la composition suivante, en molarités : palladium 0,1 éthylènediamine 3 oxalate 0,5 pentoxyde d'arsenic 10⁻³ imidazole 0,4 hydrazine 1 Son pH est égal à 9. From the stock solution of Example 2, a bath is prepared having the following composition, in molarities: palladium 0.1 ethylenediamine 3 oxalate 0.5 arsenic pentoxide 10⁻³ imidazole 0.4 hydrazine 1 Its pH is equal to 9.

Dans les mêmes conditions d'utilisation qu'aux exemples précédents, on obtient une vitesse de dépôt de 5 microns/­heure pendant 5 heures.In the same conditions of use as in the examples above, a deposition rate of 5 microns / hour for 5 hours is obtained.

Exemple 13Example 13

Le bain diffère de celui de l'exemple 12 par le remplacement du pentoxyde d'arsenic par du sulfate de cuivre à une concentration de 1,7.10⁻⁴M, le pH étant égal à 9,5.The bath differs from that of Example 12 by replacing the arsenic pentoxide with copper sulphate at a concentration of 1.7.10⁻⁴M, the pH being equal to 9.5.

Dans les mêmes conditions d'utilisation, on obtient une vitesse de dépôt de 5 microns/heure pendant 8 heures, ce qui représente une épaisseur de revêtement de palladium de 40 microns. Un tel revêtement n'a jamais été obtenu précédemment par dépôt chimique autocatalytique.Under the same conditions of use, a deposition rate of 5 microns / hour is obtained for 8 hours, which represents a palladium coating thickness of 40 microns. Such a coating has never been obtained previously by autocatalytic chemical deposition.

Exemple 14Example 14

Le bain diffère de celui de l'exemple 12 par le remplacement du pentoxyde d'arsenic par de l'iodate de potassium à la même concentration, le pH étant ici encore égal à 9,5.The bath differs from that of Example 12 by replacing the arsenic pentoxide with potassium iodate at the same concentration, the pH here again being equal to 9.5.

On obtient, toujours dans les mêmes conditions, une vitesse de dépôt de 1,5 micron/heure pendant 10 heures.Obtained, always under the same conditions, a deposition rate of 1.5 microns / hour for 10 hours.

Exemple 15Example 15

Le bain s'écarte de celui de l'exemple précédent en ce que la concentration en iodate de potassium est réduite à 10⁻⁴M.The bath differs from that of the previous example in that the potassium iodate concentration is reduced to 10⁻⁴M.

On observe dans les conditions d'utilisation habituelles une vitesse de dépôt de 2,5 microns/heure pendant 10 heures.A deposition rate of 2.5 microns / hour for 10 hours is observed under the usual conditions of use.

Exemple 16Example 16

Le bain diffère de ceux des deux exemples précédents en ce que la concentration en iodate de potassium est ramenée à 10⁻⁵M.The bath differs from those of the two previous examples in that the potassium iodate concentration is reduced to 10⁻⁵M.

Dans les mêmes conditions d'utilisation, on obtient une vitesse de dépôt de 4,5 microns/heure pendant 30 heures, soit une épaisseur totale de 135 microns. La dureté de ce dépôt est d'environ 450 HV₂₅, comparable à celle d'un dépôt de nickel chimique autocatalytique. L'analyse de ce dépôt à la microsonde électronique montre qu'il ne contient que du palladium, dans la limite de détection de cette technique.Under the same conditions of use, a deposition rate of 4.5 microns / hour for 30 hours is obtained, ie a total thickness of 135 microns. The hardness of this deposit is approximately 450 HV₂₅, comparable to that of a deposit of electroless chemical nickel. Analysis of this deposit with the electron microprobe shows that it contains only palladium, within the limit of detection of this technique.

Le même bain à la température de 60°C a fourni une vitesse de dépôt de 1,5 micron/heure pendant 3 heures.The same bath at a temperature of 60 ° C provided a deposition rate of 1.5 microns / hour for 3 hours.

Exemple 17Example 17

A partir de la solution-mère de l'exemple 2, on prépare un bain ayant la composition suivante, en molarités : palladium 0,19 éthylènediamine 1 oxalate 0,19 pentoxyde d'arsenic 6,5.10⁻⁴ imidazole 0,3 hydrazine 0,14 le pH étant porté à une valeur supàérieure ou égale à 13 par de l'hydroxyde de potassium. From the stock solution of Example 2, a bath is prepared having the following composition, in molarities: palladium 0.19 ethylenediamine 1 oxalate 0.19 arsenic pentoxide 6.5.10⁻⁴ imidazole 0.3 hydrazine 0.14 the pH being brought to a value greater than or equal to 13 by potassium hydroxide.

Ce bain peut être utilisé dans une gamme de températures de 75 à 90°C, la vitesse de dépôt variant entre 4 et 25 microns/heure. Le dépôt obtenu, dont la croissance est du type colonnaire, présente un aspect de surface très sain et légèrement fissuré dans sa partie externe (dépôt à croissance rapide).This bath can be used in a temperature range from 75 to 90 ° C, the deposition rate varying between 4 and 25 microns / hour. The deposit obtained, whose growth is of the columnar type, has a very healthy surface appearance and slightly cracked in its external part (rapid growth deposit).

Exemple 18Example 18

On utilise le bain de l'exemple 16 pour revêtir une plaquet­ te céramique en carbure de silicium mesurant approximative­ment 10 mm x 8 mm x 3 mm ayant subi préalablement un traite­ment de surface approprié. A titre indicatif, ce traitement de surface comporte les étapes suivantes :
a) dégraissage chimique pendant 10 mn dans une solution ayant la composition suivante, à 90°C : hydroxide de sodium 120 g/l phosphate trisodique 100 g/l perborate de sodium NaBO₂.H₂O₂.H₂O 50 g/l mouillant (type Teepol) 100 ml/l
b) Après rinçage soigné à l'eau désionisée, immersion dans une solution chlorhydrique à 5 g/l de chlorure de palladium, pendant 10 à 15 mn.
c) Nouveau rinçage à l'eau désionisée puis immersion dans de l'hydrazine hydratée pure pendant 3 à 5 mn.
d) Nouveau rinçage à l'eau désionisée.The bath of Example 16 is used to coat a plate te silicon carbide ceramic measuring approximately 10 mm x 8 mm x 3 mm having previously undergone an appropriate surface treatment. As an indication, this surface treatment comprises the following stages:
a) chemical degreasing for 10 min in a solution having the following composition, at 90 ° C: sodium hydroxide 120 g / l trisodium phosphate 100 g / l sodium perborate NaBO₂.H₂O₂.H₂O 50 g / l wetting agent (Teepol type) 100 ml / l
b) After careful rinsing with deionized water, immersion in a hydrochloric solution containing 5 g / l of palladium chloride, for 10 to 15 minutes.
c) Rinsing again with deionized water then immersion in pure hydrated hydrazine for 3 to 5 minutes.
d) Rinsing again with deionized water.

La plaquette est alors introduite dans le bain selon l'in­vention et la réaction de dépôt démarre dès que sa tempéra­ture de surface atteint celle du bain.The wafer is then introduced into the bath according to the invention and the deposition reaction starts as soon as its surface temperature reaches that of the bath.

A la température de 70°C on obtient une vitesse de dépôt de 4,5 microns/heure pendant 2 heures. Le dépôt est sain et adhérent.At a temperature of 70 ° C., a deposition rate of 4.5 microns / hour is obtained for 2 hours. The deposit is healthy and adherent.

Exemple 19 : Bain pour le dépôt d'un alliage palladium-­platineEXAMPLE 19 Bath for the Deposit of a Palladium-Platinum Alloy

A partir des solutions-mères des exemples 1 et 2, on prépare un bain ayant la composition suivante, en molarités : palladium 0,03 platine II 0,06 éthylènediamine 2,7 oxalate 0,2 pentoxyde d'arsenic 10⁻³ imidazole 0,4 hydrazine 1 From the stock solutions of Examples 1 and 2, a bath is prepared having the following composition, in molarities: palladium 0.03 platinum II 0.06 ethylenediamine 2.7 oxalate 0.2 arsenic pentoxide 10⁻³ imidazole 0.4 hydrazine 1

Le pH de ce bain est égal à 10,5. Dans les conditions d'utilisation des exemples 5 à 15, on obtient une vitesse de dépôt de 3 microns/heure pendant 1 heure. L'analyse du dépôt montre qu'il s'agit d'un alliage composé de 80% de palladium et de 20% de platine en masse.The pH of this bath is equal to 10.5. Under the conditions of use of Examples 5 to 15, a deposition rate of 3 microns / hour for 1 hour is obtained. Analysis of the deposit shows that it is an alloy composed of 80% palladium and 20% platinum by mass.

Les bains selon l'invention ont une durée de vie avec recharge périodique pratiquement illimitée.The baths according to the invention have a practically unlimited lifetime with periodic recharging.

Les Tableaux 1 et 2 indiquent les gammes de compositions et de conditions d'utilisation des bains au platine et au palladium respectivement. La charge du bain est le rapport entre la surface à revêtir et le volume du bain. Les colonnes mini et maxi indiquent les valeurs limites. La colonne "optimal" indique la valeur ou la gamme de valeurs préférée pour chaque paramètre.Tables 1 and 2 indicate the ranges of compositions and conditions of use of the platinum and palladium baths respectively. The load of the bath is the ratio between the surface to be coated and the volume of the bath. The minimum and maximum columns indicate the limit values. The "optimal" column indicates the preferred value or range of values for each parameter.

La stabilité des bains selon l'invention permet d'y intro­duire des particules à inclure dans les dépôts, comme décrit dans le Brevet No 2 590 595 précité. Ces particules (céramique telle qu'alumine ou yttrine, métal ou alliage) sont obtenues par broyage en présence de la solution-mère et d'un défloculant. Tableau 1 Constituant ou paramètre Mini Maxi Optimal platine II 0,05 0,15 0,10 éthylènediamine 0,10 4,0 1 à 3 anions oxalate 0,05 0,15 0,10 pentoxyde d'arsenic 10⁻⁵ 5.10⁻³ 6,5.10⁻⁴ imidazole 2.10⁻¹ 5.10⁻¹ 3.10⁻¹ hydrazine hydratée 5.10⁻² 5 1 à 4 pH 10 14 13 température (°C) 70 105 80 à 90 Tableau 2 Constituant ou paramètre Mini Maxi Optimal palladium II 10⁻² 0,3 0,1 à 0,2 anions oxalate 0,02 0,3 0,1 à 0,2 éthylènediamine 1 4 2 à 3 pentoxyde d'arsenic 10⁻⁴ 10⁻² 10⁻³ ou sulfate de cuivre 10⁻⁵ 10⁻³ 2.10⁻⁴ ou iodate de potassium 10⁻⁶ 10⁻³ 10⁻⁵ imidazole 0,2 0,6 0,4 hydrazine hydratée 0,1 2,5 1 pH 8,5 14 9,5 température (°C) 40 105 70 charge du bain (dm2/1) 3 <2 The stability of the baths according to the invention makes it possible to introduce therein particles to be included in the deposits, as described in the aforementioned Patent No. 2,590,595. These particles (ceramic such as alumina or yttrine, metal or alloy) are obtained by grinding in the presence of the mother solution and a deflocculant. Table 1 Constituent or parameter Mini Maxi Optimal platinum II 0.05 0.15 0.10 ethylenediamine 0.10 4.0 1 to 3 oxalate anions 0.05 0.15 0.10 arsenic pentoxide 10⁻⁵ 5.10⁻³ 6.5.10⁻⁴ imidazole 2.10⁻¹ 5.10⁻¹ 3.10⁻¹ hydrated hydrazine 5.10⁻² 5 1 to 4 pH 10 14 13 temperature (° C) 70 105 80 to 90 Constituent or parameter Mini Maxi Optimal palladium II 10⁻² 0.3 0.1 to 0.2 oxalate anions 0.02 0.3 0.1 to 0.2 ethylenediamine 1 4 2 to 3 arsenic pentoxide 10⁻⁴ 10⁻² 10⁻³ or copper sulfate 10⁻⁵ 10⁻³ 2.10⁻⁴ or potassium iodate 10⁻⁶ 10⁻³ 10⁻⁵ imidazole 0.2 0.6 0.4 hydrated hydrazine 0.1 2.5 1 pH 8.5 14 9.5 temperature (° C) 40 105 70 bath load (dm2 / 1) 3 <2

Claims (15)

1.- Bain aqueux pour le dépôt chimique de platine et/ou de palladium, contenant un composé du métal ou de chacun des métaux à déposer et de l'hydrazine comme réducteur, caractérisé en ce que ledit composé est un oxalate et que le bain contient de l'éthylènediamine comme complexant et au moins un stabilisant, ce bain étant fortement basique et ayant une action autocatalytique.1.- Aqueous bath for the chemical deposition of platinum and / or palladium, containing a compound of the metal or of each of the metals to be deposited and of hydrazine as reducing agent, characterized in that said compound is an oxalate and that the bath contains ethylenediamine as complexing agent and at least one stabilizer, this bath being strongly basic and having an autocatalytic action. 2.- Bain selon la revendication 1, caractérisé en ce qu'il contient du platine II à une concentration comprise entre 0,05 et 0,15 ion-gramme par litre environ.2. A bath according to claim 1, characterized in that it contains platinum II at a concentration of between 0.05 and 0.15 gram ion per liter approximately. 3.- Bain selon la revendication 2, caractérisé en ce qu'il contient les constituants suivants dans les gammes de molarités suivantes : éthylènediamine 0,1 à 4 anions oxalate 0,05 à 0,15 pentoxyde d'arsenic 10⁻⁵ à 5.10⁻³ imidazole 0,2 à 0,5 hydrazine 0,05 à 5 son pH étant compris entre 10 et 14 environ.
3.- Bath according to claim 2, characterized in that it contains the following constituents in the following ranges of molarities: ethylenediamine 0.1 to 4 oxalate anions 0.05 to 0.15 arsenic pentoxide 10⁻⁵ to 5.10⁻³ imidazole 0.2 to 0.5 hydrazine 0.05 to 5 its pH being between approximately 10 and 14.
4.- Bain selon la revendication 3, caractérisé en ce que sa composition en molarités est sensiblement la suivante : platine II 0,1 éthylènediamine 1 à 3 anions oxalate 0,1 pentoxyde d'arsenic 6,5.10⁻⁴ imidazole 0,3 hydrazine 1 à 4 son pH étant 13 environ.
4.- Bath according to claim 3, characterized in that its molar composition is substantially as follows: platinum II 0.1 ethylenediamine 1 to 3 oxalate anions 0.1 arsenic pentoxide 6.5.10⁻⁴ imidazole 0.3 hydrazine 1 to 4 its pH being approximately 13.
5.- Procédé de préparation d'un bain selon l'une des reven­dications 2 à 4, caractérisé en ce qu'on prépare d'abord une solution-mère contenant du platine II, de l'éthylène­diamine et des anions oxalate sensiblement aux mêmes concen­trations que le bain à obtenir et ayant sensiblement le même pH que celui-ci, et qu'on y ajoute ensuite le ou les stabilisant(s) et l'hydrazine.5.- A method of preparing a bath according to one of claims 2 to 4, characterized in that first preparing a stock solution containing platinum II, ethylenediamine and oxalate anions substantially the same concentrations as the bath to be obtained and having substantially the same pH as the latter, and then adding thereto the stabilizer (s) and hydrazine. 6.- Procédé selon la revendication 5, caractérisé en ce que la préparation de la solution-mère comporte les étapes suivantes : a) on introduit de l'acide hexachloroplatinique dans une solution aqueuse d'hydroxyde de potassium, b) on ajoute de l'acide oxalique et on chauffe pour dissou­dre celui-ci et le faire réagir avec l'hexachloroplatinate de potassium, c) on laisse reposer la solution, d) on ajoute de l'éthylènediamine et on filtre, e) on ajuste le pH par addition d'hydroxyde de potassium. 6.- Method according to claim 5, characterized in that the preparation of the mother solution comprises the following steps: a) hexachloroplatinic acid is introduced into an aqueous potassium hydroxide solution, b) oxalic acid is added and the mixture is heated to dissolve it and react it with potassium hexachloroplatinate, c) the solution is left to stand, d) ethylenediamine is added and filtered, e) the pH is adjusted by adding potassium hydroxide. 7.- Procédé selon la revendication 6, comportant en outre les caractéristiques suivantes :
- la quantité d'acide oxalique utilisée est d'environ 40 moles pour 1 ion-gramme de platine,
- la quantité d'éthylènediamine utilisée est d'au moins 4 moles pour 1 ion-gramme de platine,
- après addition de l'éthylènediamine et avant filtration, on concentre la solution par évaporation,
- après ajustement du pH on filtre de nouveau pour éliminer l'oxalate de potassium précipité.7.- Method according to claim 6, further comprising the following characteristics:
- the amount of oxalic acid used is approximately 40 moles for 1 gram ion of platinum,
- the amount of ethylenediamine used is at least 4 moles per 1 gram gram of platinum,
- after addition of ethylenediamine and before filtration, the solution is concentrated by evaporation,
- After adjusting the pH, it is filtered again to remove the precipitated potassium oxalate. 8.- Bain selon la revendication 1, caractérisé en ce qu'il contient du palladium à une concentration comprise entre 0,01 et 0,3 ion-gramme par litre environ.8. Bath according to claim 1, characterized in that it contains palladium at a concentration of between 0.01 and 0.3 gram ion per liter approximately. 9.- Bain selon la revendication 8, caractérisé en ce qu'il contient les constituants suivants dans les gammes de molarités suivantes : éthylènediamine 1 à 4 anions oxalate 0,02 à 0,3 pentoxyde d'arsenic 10⁻⁴ à 10⁻² ou sulfate de cuivre 10⁻⁵ à 10⁻³ ou iodate de potassium 10⁻⁶ à 10⁻³ imidazole 0,2 à 0,6 hydrazine 0,1 à 2,5 son pH étant compris entre 8,5 et 14 environ.
9. A bath according to claim 8, characterized in that it contains the following constituents in the following ranges of molarities: ethylenediamine 1 to 4 oxalate anions 0.02 to 0.3 arsenic pentoxide 10⁻⁴ to 10⁻² or copper sulfate 10⁻⁵ to 10⁻³ or potassium iodate 10⁻⁶ to 10⁻³ imidazole 0.2 to 0.6 hydrazine 0.1 to 2.5 its pH being between 8.5 and 14 approximately.
10.- Bain selon la revendication 9, caractérisé en ce que sa composition en molarités est sensiblement la sui­vante: palladium 0,1 à 0,2 anions oxalate 0,1 à 0,2 pentoxyde d'arsenic 10⁻³ ou sulfate de cuivre 2.10⁻⁴ ou iodate de potassium 10⁻⁵ imidazole 0,4 hydrazine 1 son pH étant 9,5 environ.
10.- Bath according to claim 9, characterized in that its molar composition is substantially as follows: palladium 0.1 to 0.2 oxalate anions 0.1 to 0.2 arsenic pentoxide 10⁻³ or copper sulfate 2.10⁻⁴ or potassium iodate 10⁻⁵ imidazole 0.4 hydrazine 1 its pH being approximately 9.5.
11.- Procédé de préparation d'un bain selon l'une des revendications 8 à 10, caractérisé en ce qu'on prépare d'abord une solution-mère concentrée contenant des ions palladium, de l'éthylènediamine et des anions oxalate à des concentrations plus élevées que le bain à obtenir, et qu'on y ajoute ensuite, après dilution, le ou les stabi­lisant(s) et l'hydrazine.11.- A method of preparing a bath according to one of claims 8 to 10, characterized in that a concentrated stock solution first containing palladium ions, ethylenediamine and oxalate anions at higher concentrations than the bath to be obtained, and then added thereto, after dilution, the stabilizer (s) and hydrazine. 12.- Procédé selon la revendication 11, caractérisé en ce que la préparation de la solution-mère comporte les étapes suivantes : a) on dissout du chlorure de palladium dans une solution aqueuse d'acide chlorhydrique, b) on neutralise la solution par addition d'une solution aqueuse d'hydroxyde de potassium jusqu'à précipitation du palladium sous forme d'hydroxyde, c) on filtre pour recueillir l'hydroxyde de palladium, d) on dissout l'hydroxyde de palladium dans une solution aqueuse d'acide oxalique, et e) on ajoute de l'éthylènediamine anhydre jusqu'à obtention d'un pH d'environ 10. 12.- Method according to claim 11, characterized in that the preparation of the mother solution comprises the following steps: a) palladium chloride is dissolved in an aqueous hydrochloric acid solution, b) the solution is neutralized by adding an aqueous solution of potassium hydroxide until the palladium has precipitated in the form of hydroxide, c) filtering to collect the palladium hydroxide, d) the palladium hydroxide is dissolved in an aqueous solution of oxalic acid, and e) anhydrous ethylenediamine is added until a pH of approximately 10 is obtained. 13.- Procédé de préparation d'un bain selon la revendica­tion 1 pour le dépôt simultané de platine et de palladium, caractérisé en ce qu'on mélange une solution-mère obtenue par le procédé selon l'une des revendications 5 à 7, une solution-mère obtenue par le procédé selon l'une des reven­dications 10 à 12, et de l'eau de dilution en quantité convenable pour obtenir les concentrations voulues en platine et en palladium, et qu'on ajoute le ou les stabili­sant(s) et l'hydrazine.13.- A method of preparing a bath according to claim 1 for the simultaneous deposition of platinum and palladium, characterized in that a stock solution obtained by the method according to one of claims 5 to 7 is mixed, a stock solution obtained by the method according to one of claims 10 to 12, and dilution water in an amount suitable for obtaining the desired concentrations of platinum and palladium, and adding the stabilizer (s) and hydrazine. 14.- Solution-mère telle que préparée lors de la mise en oeuvre du procédé selon l'une des revendications 5 à 7, ayant sensiblement la composition suivante en mola­rités : platine II 0,1 ions oxalate 0,1 éthylènediamine 1,2 et ayant un pH de 13 environ.
14.- Stock solution as prepared during the implementation of the method according to one of claims 5 to 7, having substantially the following composition in molarities: platinum II 0.1 oxalate ions 0.1 ethylenediamine 1.2 and having a pH of about 13.
15.- Solution-mère telle que préparée lors de la mise en oeuvre du procédé selon l'une des revendications 11 et 12, ayant sensiblement la composition suivante en mola­rités : palladium 0,1 à 0,2 ions oxalate 0,1 à 0,19 éthylènediamine 1 son pH étant compris entre 9 et 12.
15.- Stock solution as prepared during the implementation of the method according to one of claims 11 and 12, having substantially the following composition in molarities: palladium 0.1 to 0.2 oxalate ions 0.1 to 0.19 ethylenediamine 1 its pH being between 9 and 12.
EP90402778A 1989-10-11 1990-10-05 Hydrazinbath for chemical plating platin and or palladium and process for preparing such a bath Withdrawn EP0423005A1 (en)

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FR8913294 1989-10-11
FR8913294A FR2652822B1 (en) 1989-10-11 1989-10-11 HYDRAZINE BATH FOR THE CHEMICAL DEPOSITION OF PLATINUM AND / OR PALLADIUM, AND METHOD FOR MANUFACTURING SUCH A BATH.

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Cited By (4)

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US5882736A (en) * 1993-05-13 1999-03-16 Atotech Deutschland Gmbh palladium layers deposition process
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US9101915B2 (en) 2012-12-18 2015-08-11 Umicore Ag & Co. Kg Catalyst particles comprising a layered core-shell-shell structure and method of their manufacture
US9440224B2 (en) 2012-12-18 2016-09-13 Umicore Ag & Co. Kg Catalyst particles comprising hollow multilayered base metal-precious metal core/shell particles and method of their manufacture

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CN114773181A (en) * 2022-03-08 2022-07-22 徐州浩通新材料科技股份有限公司 Preparation method of hydrated bis (palladium (II) oxalate acid

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1771053A1 (en) * 1968-03-28 1971-11-25 Telefunken Patent Process for the electroless deposition of metal layers of the platinum metal group on surfaces of metallic and non-metallic parts

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2915406A (en) * 1958-03-03 1959-12-01 Int Nickel Co Palladium plating by chemical reduction
US3704156A (en) * 1970-07-13 1972-11-28 Du Pont Catalyst solution for electroless plating on nonconductors
US4006047A (en) * 1974-07-22 1977-02-01 Amp Incorporated Catalysts for electroless deposition of metals on comparatively low-temperature polyolefin and polyester substrates

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1771053A1 (en) * 1968-03-28 1971-11-25 Telefunken Patent Process for the electroless deposition of metal layers of the platinum metal group on surfaces of metallic and non-metallic parts

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5882736A (en) * 1993-05-13 1999-03-16 Atotech Deutschland Gmbh palladium layers deposition process
DE102005046351A1 (en) * 2005-09-28 2007-04-05 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Brake lining for a disk brake of a commercial vehicle comprises a friction lining and a support plate with reinforcing elements for receiving active braking forces
US9101915B2 (en) 2012-12-18 2015-08-11 Umicore Ag & Co. Kg Catalyst particles comprising a layered core-shell-shell structure and method of their manufacture
US9440224B2 (en) 2012-12-18 2016-09-13 Umicore Ag & Co. Kg Catalyst particles comprising hollow multilayered base metal-precious metal core/shell particles and method of their manufacture

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JPH03134178A (en) 1991-06-07
US5085693A (en) 1992-02-04
FR2652822A1 (en) 1991-04-12

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