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EP0149830B2 - Electrolytic bath for the deposition of thin layers of pure gold - Google Patents
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EP0149830B2 - Electrolytic bath for the deposition of thin layers of pure gold - Google Patents

Electrolytic bath for the deposition of thin layers of pure gold Download PDF

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Publication number
EP0149830B2
EP0149830B2 EP19840115879 EP84115879A EP0149830B2 EP 0149830 B2 EP0149830 B2 EP 0149830B2 EP 19840115879 EP19840115879 EP 19840115879 EP 84115879 A EP84115879 A EP 84115879A EP 0149830 B2 EP0149830 B2 EP 0149830B2
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acid
methylene
phosphonic
bath
complexing agent
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EP0149830A3 (en
EP0149830B1 (en
EP0149830A2 (en
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Heinz Emmenegger
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H E Finishing SA
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H E Finishing SA
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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/02Electroplating: Baths therefor from solutions
    • C25D3/48Electroplating: Baths therefor from solutions of gold

Definitions

  • the present invention relates to an electrolytic bath for depositing thin layers (of the order of at least 0.5 ⁇ ) of pure gold on passive surfaces (for example stainless steel, Ti, Mo, alloys based on Cr and of Ni).
  • passive surfaces for example stainless steel, Ti, Mo, alloys based on Cr and of Ni.
  • the baths used for the galvanic deposition of gold are generally prepared from solutions of potassium aurocyanide KAu (CN) 2 , to which various salts, acids or alkaline products are added, according to the methods, to improve the electrical conductivity of the bath and the crystallization conditions of the metal.
  • the aurocyanide is only stable up to a pH of around 3 and, below this value, it decomposes into insoluble yellow CN gold cyanide and hydrocyanic acid HCN.
  • very low pH baths is especially essential to deposit a thin layer of adherent pure gold on objects whose surface is highly passive, that is to say, for example stainless steel, alloys containing a high proportion of chromium and nickel, in titanium, in molybdenum, or on surfaces having previously undergone a galvanic chromium plating, a chemical nickel plating or a coating of molybdenum-manganese alloy.
  • compositions as disclosed in the examples of US Pat. No. 4,168,214 are in practice unusable for obtaining electrolytic baths having a pH of less than about 0.4.
  • these baths have the drawback, in particular with regard to environmental protection, of containing alkaline cyanides.
  • the object of this invention therefore consists in providing an electrolytic bath on the deposit of thin layers (of the order of ⁇ C, 5, ⁇ ) of pure gold (24cts) on passive surfaces, which adhere perfectly to said passive surfaces and can be used as a bonding layer for the subsequent deposition of thicker layers of a gold alloy, this bath having a pH of at most 0.4.
  • the electrolytic bath according to the invention contains from 0.5 to 20 g / I of gold in the form of an auricyanide of an alkali metal, in which the gold is trivalent, and at least an acid present in sufficient concentration for the pH of this bath to be at most 0.4 and is characterized in that the acid is at least one organic acid chosen from the group comprising sufamic acid, monochloroacetic acids, dichlo - racetic and trichloroacetic, malic acid, and 1-hydroxy-1, 1-ethylidene-diphosphoric, hydroxy-methyl-phosphoric and amino-tris (methylene-phosphonic) acids, and mixtures thereof, or else sulfuric acid in combination with at least one organic complexing agent chosen from the alkaline salts of diethylene-triamine-penta- (methylene-phosphonic), ethylene-diamine-tetra (methylene-phosphonic), hexamethylene-diamine-tetra acids - (
  • this bath may contain the auricyanide in the form of potassium auricyanide KAu (CN) 4 or sodium auricyanide NaAu (CN) 4 , and its pH is preferably between 0.1 and 0.3.
  • the acid concentration being relatively high, it does not prove necessary to add conductive salts, the solution being sufficiently electrically conductive.
  • These acids can be used either alone or mixed with each other, in concentrations of 40 to 500 g / l, except for sulfamic acid, the solubility of which in water is limited and which can be present in 100 g / I at saturation, which is reached for a concentration of approximately 150 g / I at room temperature.
  • complexing agents as well as other complexing agents such as amino-carbonic acids (see for example DE 3,012,999), cannot be used in large quantities because they risk precipitating.
  • other compounds mentioned below can be introduced into the electrolytic bath according to the invention, therefore having a pH of less than 0.4, as complexing agents and without precipitating, in quantities at least greater than 20 g / I.
  • These compounds are N-carboxymethyl-aspartic and N, N-bis (carboxymethyl) aspartic acids having the following formulas: or the salts thereof, as well as the compound represented by the following formula, where R is an alkyl or alkylene group having 1 to 5 C atoms, or the salts thereof.
  • the baths are generally used at room temperature, with platinum titanium or graphite anodes.
  • platinum titanium or graphite anodes For certain applications, in particular for coating particularly passive surfaces, it is possible to raise the working temperature of these baths up to 80 ° C.
  • the chemicals which enter into their composition not being volatile, and having a perfect stability at this temperature, there does not follow any loss or any change in the behavior of the bath during electrolysis.
  • a stainless steel wafer was treated in the bath, at room temperature, with a current density of 3 Aldm 2 for 5 minutes.
  • the pure gold deposit obtained is both perfectly adherent to the substrate and brilliant.
  • a stainless steel plate was treated in this bath, at room temperature, with a current density of 4 Aldm 2 for 4 minutes.
  • the deposit obtained is both perfectly adherent and shiny.
  • a stainless steel plate was treated in this bath, at room temperature, with a current density of 4 Aldm 2 for 3 minutes.
  • the deposit obtained is both perfectly adherent and shiny.
  • This bath was intentionally polluted with 50 mg / I of iron.
  • the addition of 4 g / l of EDTA makes it possible to obtain, under the same electrolysis conditions, a deposit of pure yellow and shiny gold.
  • the stainless steel plate treated in this bath at a current density of 5 A / dm 2 for 5 minutes, had an adherent and shiny gold layer of 0.2 to 0.3 ⁇

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Electroplating Methods And Accessories (AREA)

Description

La présente invention concerne un bain électrolytique pour le dépôt de couches minces (de l'ordre de 0,5 µ au moins) d'or pur sur des surfaces passives (par exemple acier inoxydable, Ti, Mo, alliages à base de Cr et de Ni).The present invention relates to an electrolytic bath for depositing thin layers (of the order of at least 0.5 μ) of pure gold on passive surfaces (for example stainless steel, Ti, Mo, alloys based on Cr and of Ni).

Les bains utilisés pour la déposition galvanique de l'or sont en général préparés à partir de solutions d'auro- cyanure de potassium KAu(CN)2, auxquelles on ajoute différents sels, acides ou produits alcalins, selon les procédés, pour améliorer la conductibilité électrique du bain et les conditions de cristallisation du métal. L'auro- cyanure n'est toutefois stable que jusqu'à un pH d'environ 3 et, au-dessous de cette valeur, il se décompose en cyanure d'or Au CN jaune insoluble et un acide cyanhydrique HCN. Dans la pratique, il est parfois souhaitable de pouvoir déposer de l'or ou un alliage d'or en milieu très acide, donc en utilisant des solutions dont le pH est inférieur à 3. Pour y parvenir, il est nécessaire d'utiliser un sel d'or stable à un pH bas, ce qui est le cas pour l'auricyanure de potassium KAu(CN)4, dans lequel l'or est trivalent.The baths used for the galvanic deposition of gold are generally prepared from solutions of potassium aurocyanide KAu (CN) 2 , to which various salts, acids or alkaline products are added, according to the methods, to improve the electrical conductivity of the bath and the crystallization conditions of the metal. However, the aurocyanide is only stable up to a pH of around 3 and, below this value, it decomposes into insoluble yellow CN gold cyanide and hydrocyanic acid HCN. In practice, it is sometimes desirable to be able to deposit gold or a gold alloy in a very acid medium, therefore using solutions whose pH is less than 3. To achieve this, it is necessary to use a stable gold salt at low pH, which is the case for potassium auricyanide KAu (CN) 4 , in which gold is trivalent.

Ce complexe cyanuré d'or trivalent est déjà mentionné notamment dans le brevet US 4 168 214, qui décrit un bain contenant un cyanure de métal alcalin, un sel tel qu'un nitrate, et dont le pH est ajusté avec de l'acide chlorhydrique à 0,1-1,5.This cyanide complex of trivalent gold is already mentioned in particular in US Pat. No. 4,168,214, which describes a bath containing an alkali metal cyanide, a salt such as a nitrate, and the pH of which is adjusted with hydrochloric acid. at 0.1-1.5.

L'emploi de bains à pH très bas est surtout indispensable pour effectuer la déposition d'une couche mince d'or pur adhérente sur des objects dont la surface est fortement passive, c'est-à-dire par exemple en acier inoxydable, en alliages contenant une forte proportion de chrome et de nickel, en titane, en molybdène, ou sur des surfaces ayant subi préalablement un chromage galvanique, un nickelage chimique ou un revêtement d'alliage molybdène-manganèse.The use of very low pH baths is especially essential to deposit a thin layer of adherent pure gold on objects whose surface is highly passive, that is to say, for example stainless steel, alloys containing a high proportion of chromium and nickel, in titanium, in molybdenum, or on surfaces having previously undergone a galvanic chromium plating, a chemical nickel plating or a coating of molybdenum-manganese alloy.

Toutefois, les compositions telles que divulguées dans les exemples du brevet US 4 168 214 sont en pratique inutilisables pour obtenir des bains électrolytiques ayant un pH inférieur à environ 0,4. De plus ces bains présentent l'inconvénient, notamment à l'égard de la protection de l'environnement, de contenir des cyanures alcalins.However, the compositions as disclosed in the examples of US Pat. No. 4,168,214 are in practice unusable for obtaining electrolytic baths having a pH of less than about 0.4. In addition, these baths have the drawback, in particular with regard to environmental protection, of containing alkaline cyanides.

Le but de cette invention consiste donc à fournir un bain électrolytique sur le dépôt de couches minces (de l'ordre de < C,5,µ) d'or pur (24cts) sur des surfaces passives, qui adhérent parfaitement auxdites surfaces passives et pouvant servir de couche d'accrochage pour le dépôt subséquent de couches plus épaisses d'un alliage d'or, ce bain ayant un pH d'au plus 0,4.The object of this invention therefore consists in providing an electrolytic bath on the deposit of thin layers (of the order of <C, 5, μ) of pure gold (24cts) on passive surfaces, which adhere perfectly to said passive surfaces and can be used as a bonding layer for the subsequent deposition of thicker layers of a gold alloy, this bath having a pH of at most 0.4.

Le bain électrolytique selon l'invention, visant à atteindre le but précité, contient de 0,5 à 20 g/I d'or sous forme d'auricyanure d'un métal alcalin, dans lequel l'or est trivalent, et au moins un acide présent en concentration suffisante pour que le pH de ce bain soit au plus de 0,4 et est caractérisé en ce que l'acide est au moins un acide organique choisi parmi le groupe comprenant l'acide sufamique, les acides monochloracétique, dichlo- racétique et trichloracétique, l'acide malique, et les acides 1-hydroxy-1 ,1-éthylidène-diphosphorique, hydroxy- méthyl-phosphorique et amino-tris(méthylène-phosphonique), et les mélanges de ceux-ci, ou bien l'acide sulfurique en combinaison avec au moins un agent complexant organique choisi parmi les sels alcalins des acides diéthylène-triamine-penta-(méthylène-phosphonique), éthylène-diamine-tétra(méthylène-phosphoni- que), hexaméthylène-diamine-tétra-(méthylène-phosphonique) et éthylène-diamine-tétraacétique, et les mélanges de ceux-ci, l'acide N-carboxyméthyl-aspartique et l'acide N,N-bis(carboxyméthyl) aspartique, ou un sel de ceux-ci, et un composé ayant la formule suivante :

Figure imgb0001
où R est un groupe alkyle ou alkylène ayant de 1 à 5 atomes de C, ou un sel de celui-ci.The electrolytic bath according to the invention, aimed at achieving the above-mentioned object, contains from 0.5 to 20 g / I of gold in the form of an auricyanide of an alkali metal, in which the gold is trivalent, and at least an acid present in sufficient concentration for the pH of this bath to be at most 0.4 and is characterized in that the acid is at least one organic acid chosen from the group comprising sufamic acid, monochloroacetic acids, dichlo - racetic and trichloroacetic, malic acid, and 1-hydroxy-1, 1-ethylidene-diphosphoric, hydroxy-methyl-phosphoric and amino-tris (methylene-phosphonic) acids, and mixtures thereof, or else sulfuric acid in combination with at least one organic complexing agent chosen from the alkaline salts of diethylene-triamine-penta- (methylene-phosphonic), ethylene-diamine-tetra (methylene-phosphonic), hexamethylene-diamine-tetra acids - (methylene-phosphonic) and ethylene-diamine-tetraacetic, and mixtures thereof, N-carboxymethyl-aspartic acid and N, N-bis (carboxymethyl) aspartic acid, or a salt thereof, and a compound having the following formula:
Figure imgb0001
where R is an alkyl or alkylene group having 1 to 5 C atoms, or a salt thereof.

Plus précisément, ce bain peut contenir l'auricyanure sous forme d'auricyanure de potassium KAu(CN)4 ou d'auricyanure de sodium NaAu(CN)4, et son pH est de préférence compris entre 0,1 et 0,3. En outre, la concentration en acide étant relativement élevée, il ne s'avère pas nécessaire de procéder à l'adjonction de sels conducteurs, la solution étant suffisamment conductrice de l'électricité.More specifically, this bath may contain the auricyanide in the form of potassium auricyanide KAu (CN) 4 or sodium auricyanide NaAu (CN) 4 , and its pH is preferably between 0.1 and 0.3. In addition, the acid concentration being relatively high, it does not prove necessary to add conductive salts, the solution being sufficiently electrically conductive.

Ces acides peuvent être utilisés soit seuls, soit mélangés les uns avec les autres, en concentrations de 40 à 500 g/I, sauf pour l'acide sulfamique dont la solubilité dans l'eau est restreinte et qui peut être présent de 100 g/I à la saturation, qui est atteinte pour une concentration d'environ 150 g/I à la température ambiante.These acids can be used either alone or mixed with each other, in concentrations of 40 to 500 g / l, except for sulfamic acid, the solubility of which in water is limited and which can be present in 100 g / I at saturation, which is reached for a concentration of approximately 150 g / I at room temperature.

Lors du traitement de pièces dans le bain précédemment, certains métaux peuvent passer en solution et, comme impuretés, perturber le dépôt d'or pur. On peut y remédier en ajoutant dans le bain d'or très acide des complexants organiques, par exemple des sels de sodium, de potassium, d'ammonium ou d'amines des acides diéthylène-triamine-penta(méthylène-phosphorique), éthylène-diamine-tétra(méthylène-phosphorique) et éthylène-diamine-tétra-acétique (EDTA), qui sont de préférence utilisés en concentrations de 1 à 20 g/I.When treating parts in the bath previously, certain metals may go into solution and, as impurities, disturb the deposition of pure gold. This can be remedied by adding organic complexing agents, for example sodium, potassium, ammonium or amine salts, to the highly acidic gold bath. diethylene-triamine-penta (methylene-phosphoric), ethylene-diamine-tetra (methylene-phosphoric) and ethylene-diamine-tetra-acetic (EDTA), which are preferably used in concentrations of 1 to 20 g / l.

Les exemples de complexants ci-dessus, de même que d'autres complexants tels que des acides amino- carboniques (voir par exemple DE 3 012 999), ne peuvent pas être utilisés en quantités importantes car ils risquent de précipiter. On a par contre trouvé que d'autres composés mentionnés ci-après peuvent être introduits dans le bain électrolytique selon l'invention, ayant donc un pH inférieur à 0,4, en tant qu'agents complexants et sans précipiter, en quantités au moins supérieures à 20 g/I. Ces composés sont les acides N-carboxyméthyl-aspartique et N,N-bis(carboxyméthyl) aspartique ayant les formules suivantes :

Figure imgb0002
ou les sels de ceux-ci, ainsi que le composé représenté par la formule suivante,
Figure imgb0003
où R est un groupe alkyle ou alkylène ayant de 1 à 5 atomes de C, ou les sels de celui-ci.The above examples of complexing agents, as well as other complexing agents such as amino-carbonic acids (see for example DE 3,012,999), cannot be used in large quantities because they risk precipitating. On the other hand, it has been found that other compounds mentioned below can be introduced into the electrolytic bath according to the invention, therefore having a pH of less than 0.4, as complexing agents and without precipitating, in quantities at least greater than 20 g / I. These compounds are N-carboxymethyl-aspartic and N, N-bis (carboxymethyl) aspartic acids having the following formulas:
Figure imgb0002
or the salts thereof, as well as the compound represented by the following formula,
Figure imgb0003
where R is an alkyl or alkylene group having 1 to 5 C atoms, or the salts thereof.

Les bains sont utilisés généralement à la température ambiante, avec des anodes en titane platiné ou en graphite. Pour certaines applications, en particulier pour le revêtement de surfaces particulièrement passives, il est possible d'élever la température de travail de ces bains jusqu'à 80 °C. Les produits chimiques qui entrent dans leur composition n'étant pas volatils, et présentant une parfaite stabilité à cette température, il ne s'ensuit aucune perte ni aucun changement dans le comportement du bain lors de l'électrolyse.The baths are generally used at room temperature, with platinum titanium or graphite anodes. For certain applications, in particular for coating particularly passive surfaces, it is possible to raise the working temperature of these baths up to 80 ° C. The chemicals which enter into their composition not being volatile, and having a perfect stability at this temperature, there does not follow any loss or any change in the behavior of the bath during electrolysis.

Les exemples qui suivent illustrent l'invention en donnant notamment plusieurs possibilités de compositions de bains utilisables pratiquement. Dans chacun de ceux-ci, la surface des objets traités dans le bain d'or a été préalablement décapé selon les procédés préparatoires habituels.The examples which follow illustrate the invention by giving in particular several possibilities of practically usable bath compositions. In each of these, the surface of the objects treated in the gold bath was previously pickled according to the usual preparatory processes.

Exemple 1Example 1

Figure imgb0004
Figure imgb0004

Une plaquette en acier inoxydable a été traitée dans le bain, à température ambiante, avec une densité de courant de 3 Aldm2 pendant 5 minutes. Le dépôt d'or pur obtenu est à la fois parfaitement adhérent au substrat et brillant.A stainless steel wafer was treated in the bath, at room temperature, with a current density of 3 Aldm 2 for 5 minutes. The pure gold deposit obtained is both perfectly adherent to the substrate and brilliant.

Exemple 2Example 2

Figure imgb0005
Figure imgb0005

Une plaquette en acier inoxydable a été traitée dans ce bain, à température ambiante, avec une densité de courant de 4 Aldm2 pendant 4 minutes. Le dépôt obtenu est à la fois parfaitement adhérent et brillant.A stainless steel plate was treated in this bath, at room temperature, with a current density of 4 Aldm 2 for 4 minutes. The deposit obtained is both perfectly adherent and shiny.

Exemple 3Example 3

Figure imgb0006
Figure imgb0006

Une plaquette en acier inoxydable a été traitée dans ce bain, à température ambiante, avec une densité de courant de 4 Aldm2 pendant 3 minutes. Le dépôt obtenu est à la fois parfaitement adhérent et brillant.A stainless steel plate was treated in this bath, at room temperature, with a current density of 4 Aldm 2 for 3 minutes. The deposit obtained is both perfectly adherent and shiny.

Exemple 4Example 4

Figure imgb0007
Figure imgb0007

Ce bain a été intentionnellement pollué par 50 mg/I de fer. Le dépôt obtenu sur une plaquette d'acier inoxydable avec une densité de courant de 3 A/dm2, durant 2 minutes, est alors sombre, brunâtre et terne. L'adjonction de 4 g/I d'EDTA permet d'obtenir, dans les mêmes conditions d'électrolyse, un dépôt d'or pur jaune et brillant.This bath was intentionally polluted with 50 mg / I of iron. The deposit obtained on a stainless steel wafer with a current density of 3 A / dm 2 , for 2 minutes, is then dark, brownish and dull. The addition of 4 g / l of EDTA makes it possible to obtain, under the same electrolysis conditions, a deposit of pure yellow and shiny gold.

Exemple 5Example 5

Figure imgb0008
Figure imgb0008

La plaquette en acier inoxydable traitée dans ce bain, à une densité de courant de 5 A/dm2 pendant 5 minutes, présentait une couche d'or adhérente et brillante de 0,2 à 0,3 µThe stainless steel plate treated in this bath, at a current density of 5 A / dm 2 for 5 minutes, had an adherent and shiny gold layer of 0.2 to 0.3 µ

Aucun précipité n'a été constaté, alors qu'un bain identique, mais contenant la même quantité d'EDTA, au lieu du complexant mentionné ci-dessus, devient rapidement trouble par suite de la formation d'un précipitéNo precipitate has been found, while an identical bath, but containing the same amount of EDTA, instead of the complexing agent mentioned above, quickly becomes cloudy as a result of the formation of a precipitate.

Exemple 6Example 6

Figure imgb0009
Figure imgb0009

L'utilisation de ce bain a conduit à des résultats similaires à ceux obtenus avec le bain de l'exemple 5 .The use of this bath led to results similar to those obtained with the bath of Example 5.

Claims (9)

1. Electrolytic bath for the deposit of thin layers of pure gold on passive surfaces, containing from 0.5 to 20 g/I of gold under the form of a gold cyanide of alkali metal, in which gold is trivalent, and at least an acid which is present in a sufficient concentration so as the pH of this bath is at most of 0.4, characterized in that the acid is at least an organic acid selected from the group comprising the sulfamic acid the mono-, di- and tri+chloroacetic acids, the malic acid, and the 1-hydroxy-1, 1-ethylidene-diphosphonic, hydroxy-methylphos- phonic and amino-tris(methylene-phosphonic) acids, and the mixtures thereof, or the sulfuric acid in combination with at least an organic complexing agent selected from the alkali salts of the diethylene-triamine-penta(methylene-phosphonic), ethylene-diaminetetra(methylene-phosphonic), hexamethylene-diamine-tetra(methylene-phosphonic) and ethylene-diamine-tetra-acetic acids, and the mixtures thereof, or the N-carboxymethyl-aspartic acid or the N,N-bis(carboxymethyl) aspartic acid, or a salt thereof, or a compound having the following formula :
Figure imgb0012
where R is an alkyl or alkylene group having from 1 to 5 carbon atoms, or a salt thereof.
2. Bath according to claim 1, characterized in that its pH is comprised between 0.1 and 0.3.
3. Bath according to claim 1 or claim 2, characterized in that the acid is present in an amount comprised between 40 and 500 g/I.
4. Bath according to one of claims 1 to 3, characterized in that, in the case of the use of an organic acid, it further contains at least an organic complexing agent.
5. Bath according to claim 4, characterized in that the organic complexing agent is selected from the alkali salts of the diethylene-triamine-penta(methylene-phosphonic), ethylene-diaminetetra(methylene-phosphonic), hexamethylene-diamine-tetra(methylene-phosphonic) and ethylene-diamine-tetra-acetic acids, and the mixtures thereof.
6. Bath according to claim 5, characterized in that the organic complexing agent is present in an amount comprised between 1 and 20 g/i.
7. Bath according to claim 4, characterized in that the organic complexing agent is the N-carboxymethyl-aspartic acid or the N,N-bis(carboxymethyl) aspartic acid, or a salt thereof.
8. Bath according to claim 4, characterized in that the organic complexing agent is a compound having the following formula :
Figure imgb0013
where R is an alkyl or alkylene group having from 1 to 5 carbon atoms, or a salt thereof.
9. Bath according to claim 7 or to claim 8, characterized in that the organic complexing agent is present in an amount higher than 20 g/I.
EP19840115879 1983-12-29 1984-12-20 Electrolytic bath for the deposition of thin layers of pure gold Expired - Lifetime EP0149830B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH6961/83 1983-12-29
CH696183A CH665656A5 (en) 1983-12-29 1983-12-29 ACID GOLD BATH AND USE OF THIS BATH IN ELECTROPLASTY.

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EP0149830A2 EP0149830A2 (en) 1985-07-31
EP0149830A3 EP0149830A3 (en) 1986-10-15
EP0149830B1 EP0149830B1 (en) 1989-04-05
EP0149830B2 true EP0149830B2 (en) 1992-05-13

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AT353071B (en) * 1977-10-06 1979-10-25 Oxy Metal Industries Corp CYANIDE-FREE BASIC SULPHITE BATH FOR ELECTROLYTIC FILLING OF GOLD-ZINC ALLOYS
US4168214A (en) * 1978-06-14 1979-09-18 American Chemical And Refining Company, Inc. Gold electroplating bath and method of making the same
GB2038361B (en) * 1978-11-11 1983-08-17 Ibm Trivalent chromium plating bath
DE3012999C2 (en) * 1980-04-03 1984-02-16 Degussa Ag, 6000 Frankfurt Bath and process for the galvanic deposition of high-gloss and ductile gold alloy coatings
DE3021665A1 (en) * 1980-06-10 1981-12-17 Degussa Ag, 6000 Frankfurt STRONG ACID GOLD ALLOY BATH

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DE149830T1 (en) 1985-10-24
DE3477588D1 (en) 1989-05-11
EP0149830A3 (en) 1986-10-15
EP0149830B1 (en) 1989-04-05
EP0149830A2 (en) 1985-07-31
CH665656A5 (en) 1988-05-31

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