WO2016020812A1 - Bain électrolytique, procédé de dépôt électrolytique et article obtenu par ledit procédé - Google Patents

Bain électrolytique, procédé de dépôt électrolytique et article obtenu par ledit procédé Download PDF

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Publication number
WO2016020812A1
WO2016020812A1 PCT/IB2015/055817 IB2015055817W WO2016020812A1 WO 2016020812 A1 WO2016020812 A1 WO 2016020812A1 IB 2015055817 W IB2015055817 W IB 2015055817W WO 2016020812 A1 WO2016020812 A1 WO 2016020812A1
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WO
WIPO (PCT)
Prior art keywords
bath
cyanide
indium
gold
alkaline
Prior art date
Application number
PCT/IB2015/055817
Other languages
English (en)
Inventor
Gopalakrishna Kalyanarama SUBRAMANIAN
Original Assignee
Nutec International Srl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nutec International Srl filed Critical Nutec International Srl
Publication of WO2016020812A1 publication Critical patent/WO2016020812A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/58—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of copper
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/62—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of gold

Definitions

  • the invention refers to an electrolytic deposit in the form of a gold alloy in a thick layer, as well as to the method for producing the same.
  • the present invention refers to an electrolytic deposition bath for the deposition of a copper-indium-gold alloy.
  • the invention also concerns an electrolytic deposition method that uses said bath, as well as an item obtained with said method.
  • Cadmium facilitates the deposit of thick layers, that is, layers included between 1 and 800 microns, and makes it possible to obtain a yellow alloy by decreasing the quantity of copper contained in the alloy; however, cadmium is extremely toxic and its use is forbidden in several countries.
  • 18-carat cadmium- free gold alloys are also known, which contain copper and zinc. However, these deposits are too pink (titer too rich in copper).
  • Electrolytic deposits in the form of a gold alloy are also known (as well as the method for producing the latter) which use a complex of indium with an amino carboxylic acid or amino phosphonic acid base.
  • a first drawback posed by said electrolytic baths of known type lies in that in them it has been possible to observe a localized production of cyanuric acid, even if in a limited quantity, during the various additions made to the complex as required for the execution of the electrodeposition process and especially when considerable thicknesses are involved.
  • a further drawback is constituted by the fact that the items obtained are not always characterized by good weldability.
  • the present invention is based on the general idea that it is possible to overcome the drawbacks described above by replacing the use of the indium complex of the amino carboxylic or amino phosphonic type in the electrolytic deposition baths of known type.
  • the invention is based on the general consideration that the electrolytic deposition bath and the corresponding electrolytic deposition method should include the use of indium as an alkaline cyanide complex.
  • the present invention proposes an aqueous solution for the electrolytic deposition of an alloy of gold, copper, indium, containing gold in the form of an alkaline cyanide compound, copper in the form of an alkaline cyanide compound and also indium in the form of an alkaline cyanide compound, for the purpose of depositing a gold alloy of the bright yellow pinkish type on the electrode.
  • the invention refers to an electrolytic deposit in the form of a gold alloy with copper and indium as alloying metals.
  • the electrolytic deposition bath comprises gold in the form of alkaline cyanide, organometallic compounds, a surface-active substance, a complexant, free cyanide, wherein the metals making up the alloy are copper in the form of a cyanide complex and indium in complexed form, wherein the complexed form of indium is of the cyanide alkaline type.
  • the bath comprises from 1 to 12 g/1 of gold in the form of double alkaline gold-potassium cyanide.
  • the bath comprises from 20 to 80 g/1 of copper (I) in the form of double alkaline copper- potassium cyanide.
  • the bath comprises from 50 mg/1 to 2.0 g/1 of indium as cyanide indium complex.
  • the bath comprises from 8.0 to 35 g/1 of free cyanide.
  • the surface- active substance is present in a concentration included between 0.05 and 10 ml/1.
  • the bath comprises a surface-active substance selected among one of the following types: polyoxyalkylenic, ether phosphate, lauryl sulphate, dimethyldodecylamine-N- oxide, dimethyl-dodecyl-amrnonium-propanesulfonate.
  • the bath comprises an amino carboxylic complexant present in a concentration included between 0.1 and 30 g/1.
  • the bath comprises an amine in a concentration included between 0.01 and 15 g/1.
  • the bath comprises at least one conductive salt selected among one of the following types: phosphates, carbonates, citrates, sulphates, tartrates, gluconates, phosphonates.
  • the bath may also comprise the metals Ag, Zr, Sb, Sn, As, Sr, Be, Bi in negligible quantities, as pollutants.
  • the bath may also comprise gallium, selenium or tellurium in considerable quantities.
  • tellurium in a quantity included between 1.0 and 150 mg/l.
  • the alkaline cyanide indium complex comprises an indium cyanide hydroxide complex.
  • the alkaline cyanide indium complex comprises a indium cyanide ammonium complex.
  • the colour of the gold alloy deposited on the electrode is preferably included between 4N and 5N according to the NIHS.
  • gold in the form of double alkaline gold-potassium cyanide is in the form of alkaline potassium aurocyanide.
  • the invention concerns also a method for the galvanoplastic deposit of a gold alloy on an electrode immersed in a bath, wherein the bath is of the type described above, said bath making it possible to deposit a gold alloy of bright yellow pinkish type on the electrode.
  • the temperature of the bath is maintained between 50 and 80 °C.
  • the pH of the bath is maintained between 8 and 12.
  • the galvanoplastie deposit is carried out at a current density included between 0.1 and 1,5 A/dm 2 .
  • the invention also refers to an electrolytic deposit in the form of a gold alloy obtained through a method of the type described above, whose thickness is preferably included between 1 and 800 microns and which comprises copper, said deposit comprising indium as third main component, which allows a bright yellow pinkish colour shade to be obtained.
  • the invention also refers to an item obtained with the method and/or a deposit and/or a bath of the type previously described.
  • the electrolytic deposition bath, the electrolytic deposition method, as well as the item obtained with said method include a deposit with a concentration of indium in the bath that is such that a content of indium in the alloy lower than 2% is obtained.
  • Electrolysis is preferably followed by a heat treatment at a temperature of at least 500°C for at least 30 minutes in order to obtain a deposit with optimal quality.
  • the bath may also comprise a brightening substance. It is preferably a derivative of butyn-diol, a pyridine-propane sulphonate or a mixture of the two, a tin salt, sulphonated castor oil, methylimidazole, dithiocarboxylic acid like thiourea, thiobarbituric acid, imidazolidine-tione or thiomalic acid.
  • An example of deposit is a gold alloy, with no toxic metals or metalloids, in particular with no cadmium, in a yellow pinkish colour IN, with a thickness up to 800 microns, excellent brightness and long duration, with a very high resistance to wear.
  • a first example of deposit is obtained with electrolysis in an electrolytic bath of the type:
  • Triethanolamine 10 cc/1
  • Triethanolamine 8 cc/1
  • the bath comprises other metals, like for example Te, As, Se, etc., in such quantities as to obtain a cathode efficiency and therefore a carat weight preferably included between 18 and 22 kt.
  • the alkaline cyanide indium complex comprises an indium cyanide hydroxide complex.
  • the alkaline cyanide indium complex comprises a indium cyanide ammonium complex.
  • the colour of the gold alloy deposited on the electrode is preferably included between 4N and 5N according to the NIHS.
  • gold in the form of double alkaline gold-potassium cyanide is in the form of alkaline potassium aurocyanide.
  • the electrolytic bath is contained in a polypropylene or PVC tank with heat insulation coating.
  • the bath is heated by means of immersion heaters in quartz, PTFE, porcelain or stabilized stainless steel.
  • a good cathode agitation as well as a good circulation of the electrolyte must be maintained.
  • the anodes are in stainless steel, platinum, titanium coated with platinum or iridium, ruthenium or tantalium oxide, or mixtures of the last three.
  • the bath can contain the metals Ag, Cd, Zr, Sb, Sn, Sr, Be, Bi in negligible quantities.
  • the surface-active substance can be of any type that can be wetted in an alkaline cyanide media.
  • the proposed solution advantageously makes it possible to operate with higher current densities and obtain a yellow pinkish deposit that is bright and easy to weld.

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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)

Abstract

L'invention concerne un bain de dépôt électrolytique comprenant de l'or sous forme de cyanure alcalin, des composés organométalliques, une substance tensioactive, un complexant et du cyanure libre, les métaux constituant l'alliage étant le cuivre sous forme de complexe de cyanure et l'indium sous forme complexée qui permettent de déposer un alliage d'or de couleur rosâtre jaune vif sur l'électrode. Ladite forme complexée de l'indium est du type alcalin avec du cyanure. L'invention concerne également un procédé de dépôt galvanoplastique d'un alliage d'or sur une électrode immergée dans un bain, un dépôt électrolytique sous la forme d'un alliage d'or et un article obtenu avec ledit procédé.
PCT/IB2015/055817 2014-08-04 2015-07-31 Bain électrolytique, procédé de dépôt électrolytique et article obtenu par ledit procédé WO2016020812A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITVI2014A000207 2014-08-04
ITVI20140207 2014-08-04

Publications (1)

Publication Number Publication Date
WO2016020812A1 true WO2016020812A1 (fr) 2016-02-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2015/055817 WO2016020812A1 (fr) 2014-08-04 2015-07-31 Bain électrolytique, procédé de dépôt électrolytique et article obtenu par ledit procédé

Country Status (1)

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WO (1) WO2016020812A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100206739A1 (en) * 2007-09-21 2010-08-19 The Swatch Group Research And Development Ltd. Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
EP2669407A1 (fr) * 2012-06-01 2013-12-04 Bluclad S.R.L. Bains galvaniques pour obtenir un alliage d'or de bas carat, et procédé galvanique qui utilise ces bains

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100206739A1 (en) * 2007-09-21 2010-08-19 The Swatch Group Research And Development Ltd. Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
EP2669407A1 (fr) * 2012-06-01 2013-12-04 Bluclad S.R.L. Bains galvaniques pour obtenir un alliage d'or de bas carat, et procédé galvanique qui utilise ces bains

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