US3749650A - Method of electrodepositing gold alloys - Google Patents

Method of electrodepositing gold alloys Download PDF

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Publication number
US3749650A
US3749650A US00244209A US3749650DA US3749650A US 3749650 A US3749650 A US 3749650A US 00244209 A US00244209 A US 00244209A US 3749650D A US3749650D A US 3749650DA US 3749650 A US3749650 A US 3749650A
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potential
period
gold
deposition
alloys
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US00244209A
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M Dettke
R Ludwig
W Riedel
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/62—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of gold
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/18—Electroplating using modulated, pulsed or reversing current
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/615—Microstructure of the layers, e.g. mixed structure
    • C25D5/617—Crystalline layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S204/00—Chemistry: electrical and wave energy
    • Y10S204/09—Wave forms

Definitions

  • This invention relates to the electrodeposition of gold alloys from aqueous electrolytes, and particularly to a method of improving the properties of electrodeposited gold alloys by modifying the potential applied to the electrodes during deposition.
  • the improved binary, ternary, and quaternary alloys of the invention are deposited on immersed conductive objects from aqueous baths by closely controlled cycles of potential pulses, each cycle consisting of a pulse of high voltage and a duration of to 10- second, which is preceded by a period of deposition potential lasting 0.1 second or longer, and is followed by a period of about 10- to 10" second during which the potential is much lower than the deposition potential and practically zero, the several potentials being applied to the immersed object as the cathode and to the electrolyte.
  • the time integral of the high voltage pulse in each group is smaller than 5X10 voltseconds, the magnitude of the pulse is greater by about 1 to 5 volts than the deposition voltage, and is preferably between 2 and 8 times that voltage.
  • the highvoltage pulses of the several groups may be uniform or 3,749,650 Patented July 31, 1973 further modulated.
  • the potential changes generally described above have been found to polarize the free and complex metal ions in the electrolyte in such a manner as to produce the results indicated above.
  • the desired sequence of applied potentials is achieved by means of a step generator capable of producing stepped voltages of predetermined duration in a cycle including, for example, ten stages differing from each other in duration and amplitude.
  • FIG. 1 is a block diagram of a suitable generator
  • FIG. 2 diagrammatically illustrates the changes in the output potential of the generator as a function of time.
  • FIG. 1 there is seen a generator whose principal element is a decade counter 1 equipped with a 1-of-10 decoder.
  • the decoder outputs control semi-conductor switches (field effect transistors) T to T through an adapter circuit 2, the switches being arranged at the signal inputs of an integrator 3- and of an output signal amplifier 4.
  • the switches T to T select the duration of intervals t to r which are each infinitely variable by means of potentiometers P to P
  • the simultaneously selected respective switches T to T select the amplitudes of the output signals during the corresponding interval, the amplitudes being continuously adjustable by means of potentiometers P to P
  • An integrator input current I defined by the position of the associated potentiometer P is associated with each semi-conductor switch T
  • the integrator output voltage U s satisfy the equation that is, I determines the slope of U s.
  • the switch T controlled by the adapter When each of the switches T to T is closed, the switch T controlled by the adapter, is to be closed for a period which is short as compared to the time of increase of U,,s in order to discharge a capacitor C. From the moment at which a switch T is closed, there elapses a time t defined by the associated potentiometer P until U s becomes equal to the threshold potential of a comparator 5. At this moment, the comparator furnishes a pulse to the decade counter 6 and advances the counter by one unit, that is, the next output of the decoder is activated.
  • the semi-conductor switches are operated by the adapter circuit so that they set the duration and the output signal amplitude of the subsequent interval.
  • the integrator, comparator, counter, and decoder operate in a closed loop so that a new cycle of stepped potentials starts after each group of ten pulses at the counter input.
  • the counter is readily started in position 8 of a singlepole, double-throw switch by means of a gate 7 in the input circuit of the counter and stopped in position 9.
  • the high-potential pulses A A A act on the electrolyte for a duration of 10- to 10* second and that the periods of a potential not significantly dilferent from zero potential t t t extend over l0 to 10- second.
  • the high-voltage pulses employed according to the invention do not generate current variations according to Ohms law but merely cause so-called non-Faraday currents which transfer or polarize the ions and complexes present in the cathode film, but do not discharge ions in the electrolyte. These unsteady potential changes are produced in the manner indicated, the potential of the Faraday or deposition current being followed briefly by a potential peak which generates a non-Faraday current.
  • a A and A are the deposition potentials for the desired alloy composition, their magnitudes being merely presented by way of example.
  • the effective deposition periods are indicated as t t and t A A and A are the potential peaks of the non-Faraday currents which must satisfy the relationship:
  • the periods of the potential peaks A A A are approximately to 10* second and are indicated at t t r
  • the periods of zero or practically zero potential t t t having a duration of about 10 to 10- second follow the peak potentials.
  • a A A need not be zero, they must be much smaller than A A A
  • the periods of deposition potential t t t must be longer than the periods of practically zero potential t t t and the latter must be much longer than the periods of the potential peaks t t t
  • the effective deposition periods 2 t are to be selected so that the thickness of the electrodeposit during each individual period should not exceed 300 angstrom units.
  • the necessary deposition periods are of the order of 0.1 to about 100 seconds and thus much longer than the periods of peak potential. Good results are generally obtained when the growth of the electrodeposit in each deposition period is of the order of 50 angstrom units.
  • Each cycle of three groups, as illustrated in FIG. 2, is separated from the next cycle by a period of approximately 10* second in which the potential amplitude A is of the same order as A A A and approximately Zero.
  • the period is provided merely to fit the pattern to the available apparatus which includes a decade counter.
  • the number of groups in the cycle is not critical, and good results can be achieved with repeating cycles having two or four groups, each group consisting of a period of deposition voltage, a short potential peak, and a period of zero or practically zero voltage.
  • the deposition voltages A A A need not be constant in the manner illustrated, but may additionally be modulated by the use of an alternating current generator which superimposes a sine, triangle, or square wave pattern on the basic potential.
  • Gold alloy electrodeposits formed with the pattern of potentials exemplified in FIG. 2 have been found to have improved chemical, physical, and mechanical properties due to the structure of the metal.
  • the binary goldcopper alloys of the invention are distinguished by superior conductivity and low surface contact resistance.
  • the ternary gold-copper-cadmium alloy deposits are extremely ductile even in heavy coatings and are bright, and the quaternary gold-silver-nickel-palladium alloys have surprising wear resistance.
  • the electrolytes employed contain alkali metal dicyanoaurates and one or more complex bound elements of Groups IVa, Va, Ib, III], or VIII of the Periodic Table, or mixtures thereof.
  • Sources of metals to be deposited and their suitable concentrations in the electrolytes are listed below, the concentrations being expressed in milligram atom per liter:
  • the electrolytes additionally may contain the usual conductive salts and butters such as the following whose names are followed by preferred concentrations in mole/ liter:
  • the gold alloy deposits prepared according to the method of the invention have been used successfully in the electronics industry for contacts and for printed circuits, and in the jewelry trade.
  • Typical electrodeposited copper-gold alloys of the invention differ from conventionally deposited alloys of the same composition as follows:
  • a rich gold color is obtained at the mid-points of the composition ranges indicated above, that is, at 7 mg. atom/liter gold, 195 mg. atom/liter copper, 75 millimole/liter potassium cyanide and a temperature of 65:1 C.
  • EXAMPLE 2 gold as KAu(CN) 65-100 mg. atom/liter copper as K Cu(CN) 150-300 mg. atom/liter cadmium as K Cd(CN) 0.35-0.90 mg. atom/liter potassium cyanide: 60-85 millimole/liter
  • the generator was set for the following values:
  • the temperature of the electrolyte was held at i-l C. between 50 and 75 C. for controlling the color of the deposit which could also be varied by increasing the values of A A A up to 2.0, 1.7, and 2.5 v. respectively.
  • the alloys contained 70%-85% gold, 12%-22% copper, and 3%- 8% cadmium. They were extremely ductile even when deposited heavily, were bright, and had an elongation of up to 15%.
  • the Vickers hardness of some of the deposits was as high as 400 -kp./mm.
  • the electrodeposited alloy Au75-Cu22-Cd3 had an electrical conductivity of 6.7 10* ohmr cm.- as compared to a value of 5.5 10- ohmcm.- for a thermally produced alloy of the same composition.
  • the electrolyte was used within the temperature range of '60-75 C.
  • the deposits formed were bright to have a reflectance of as compared to mirror bright silver. Their color was closely similar to that of silver. They had compositions within limits of 83 %-90% gold, 7%-11% silver, 0.5%-1.0% palladium, and 2.5 %-5.0% nickel. Their wear resistance exceeded that of pure gold deposits by a factor of about 50. They showed little microstress in layers up to 8 m. and were ductile so as to make them eminently suitable for plating jewelry.
  • a method of electrodepositing a gold alloy on an electrically conductive object which comprises:

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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)
  • Crystallography & Structural Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Electroplating Methods And Accessories (AREA)
US00244209A 1971-04-24 1972-04-14 Method of electrodepositing gold alloys Expired - Lifetime US3749650A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2121150A DE2121150C3 (de) 1971-04-24 1971-04-24 Verfahren zur galvanischen Abscheidung von Goldlegierungen

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US (1) US3749650A (enExample)
JP (1) JPS544895B1 (enExample)
AT (1) AT313664B (enExample)
CA (1) CA984330A (enExample)
CH (1) CH555412A (enExample)
DE (1) DE2121150C3 (enExample)
FR (1) FR2134401B1 (enExample)
GB (1) GB1381192A (enExample)
IE (1) IE36303B1 (enExample)
IT (1) IT951424B (enExample)
NL (1) NL7205546A (enExample)
SE (1) SE393821B (enExample)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4082622A (en) * 1977-04-20 1978-04-04 Gte Automatic Electric Laboratories Incorporated Electrodeposition of ruthenium
US4105527A (en) * 1975-07-07 1978-08-08 Nipki Po Tzvetna Metalurgia Electric system for electric extraction of non-ferrous metals from their solutions
US4343684A (en) * 1980-12-19 1982-08-10 Stanley Lechtzin Method of electroforming and product
US4358351A (en) * 1980-05-31 1982-11-09 Degussa Aktiengesellschaft Alkaline bath for the electrolytic deposition of low carat yellow colored gold alloy layers
US4465564A (en) * 1983-06-27 1984-08-14 American Chemical & Refining Company, Inc. Gold plating bath containing tartrate and carbonate salts
US4840711A (en) * 1981-01-13 1989-06-20 Metafuse Limited Process for the fusion of one element into a second element
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
EP2879169A3 (en) * 2013-11-12 2015-08-26 Chipmos Technologies Inc. Method of manufacturing a silver alloy bump for a semiconductor structure using a cyanide-based plating bath
US9567684B2 (en) 2009-10-15 2017-02-14 The Swatch Group Research And Development Ltd Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic materials

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH629542A5 (de) * 1976-09-01 1982-04-30 Inoue Japax Res Verfahren und vorrichtung zur galvanischen materialablagerung.
JPS5653267A (en) * 1979-09-29 1981-05-12 Takiyasu Kk Production of fancy postdyed fabric
ITTO20070704A1 (it) * 2007-10-05 2009-04-06 Create New Technology S R L Sistema e metodo di placcatura di leghe metalliche mediante tecnologia galvanica

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4105527A (en) * 1975-07-07 1978-08-08 Nipki Po Tzvetna Metalurgia Electric system for electric extraction of non-ferrous metals from their solutions
US4082622A (en) * 1977-04-20 1978-04-04 Gte Automatic Electric Laboratories Incorporated Electrodeposition of ruthenium
US4358351A (en) * 1980-05-31 1982-11-09 Degussa Aktiengesellschaft Alkaline bath for the electrolytic deposition of low carat yellow colored gold alloy layers
US4343684A (en) * 1980-12-19 1982-08-10 Stanley Lechtzin Method of electroforming and product
US4840711A (en) * 1981-01-13 1989-06-20 Metafuse Limited Process for the fusion of one element into a second element
US4465564A (en) * 1983-06-27 1984-08-14 American Chemical & Refining Company, Inc. Gold plating bath containing tartrate and carbonate salts
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
US20140299481A1 (en) * 2007-09-21 2014-10-09 The Swatch Group Research And Development Ltd Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
US9683303B2 (en) * 2007-09-21 2017-06-20 The Swatch Group Research And Development Ltd Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
US10233555B2 (en) * 2007-09-21 2019-03-19 The Swatch Group Research And Development Ltd. Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
US10619260B2 (en) 2007-09-21 2020-04-14 The Swatch Group Research And Development Ltd. Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic metals or metalloids
US9567684B2 (en) 2009-10-15 2017-02-14 The Swatch Group Research And Development Ltd Method of obtaining a yellow gold alloy deposition by galvanoplasty without using toxic materials
EP2879169A3 (en) * 2013-11-12 2015-08-26 Chipmos Technologies Inc. Method of manufacturing a silver alloy bump for a semiconductor structure using a cyanide-based plating bath

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Publication number Publication date
FR2134401B1 (enExample) 1975-10-24
GB1381192A (en) 1975-01-22
DE2121150A1 (de) 1972-11-16
DE2121150B2 (de) 1979-12-20
CA984330A (en) 1976-02-24
FR2134401A1 (enExample) 1972-12-08
AT313664B (de) 1974-02-25
IT951424B (it) 1973-06-30
IE36303L (en) 1972-10-24
IE36303B1 (en) 1976-09-29
JPS544895B1 (enExample) 1979-03-12
SE393821B (sv) 1977-05-23
NL7205546A (enExample) 1972-10-26
DE2121150C3 (de) 1980-08-21
CH555412A (de) 1974-10-31

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JPS63297590A (ja) 高速電流反転電解によるめつき方法