EP2045343A1 - Juwelenlegierungen zur Herstellung von nickellosen Weißgoldobjekten - Google Patents

Juwelenlegierungen zur Herstellung von nickellosen Weißgoldobjekten Download PDF

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Publication number
EP2045343A1
EP2045343A1 EP08103100A EP08103100A EP2045343A1 EP 2045343 A1 EP2045343 A1 EP 2045343A1 EP 08103100 A EP08103100 A EP 08103100A EP 08103100 A EP08103100 A EP 08103100A EP 2045343 A1 EP2045343 A1 EP 2045343A1
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EP
European Patent Office
Prior art keywords
gallium
range
white gold
alloy
total weight
Prior art date
Legal status (The legal status 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 status listed.)
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Application number
EP08103100A
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English (en)
French (fr)
Inventor
Massimo Poliero
Andrea Basso
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Legor Group Srl
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Legor Group Srl
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Filing date
Publication date
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Publication of EP2045343A1 publication Critical patent/EP2045343A1/de
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C5/00—Alloys based on noble metals
    • C22C5/02—Alloys based on gold
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • C22C30/02—Alloys containing less than 50% by weight of each constituent containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • C22C30/06—Alloys containing less than 50% by weight of each constituent containing zinc

Definitions

  • the present invention relates to the use of gallium on its own or combined with other elements as a whitening element in white gold alloys for nickel-free jewellery.
  • the present invention relates to the use of gallium either directly in white gold alloys or in the master alloys for their production.
  • white gold objects refers in particular to precious objects (such as jewellery, coins and medals) obtained both using precision casting processes and through mechanical working.
  • the a* coordinate represents the position of the colour between red/magenta and green (negative values indicate a tendency towards green whilst positive values indicate a tendency towards magenta)
  • the b* coordinate indicates the position of the colour between yellow and blue (negative values indicate blue whilst positive values indicate yellow).
  • a white gold alloy is considered sufficiently white that it does not require a final rhodium plating treatment when its Cielab colour coordinates are: 0 ⁇ a ⁇ 2; 0 ⁇ b ⁇ 9.
  • the colour coordinates are 2 ⁇ a ⁇ 3.5 and 9 ⁇ b ⁇ 14, the colour is considered white but the items must be subjected to a final rhodium plating treatment.
  • a gold alloy has a "premium white” colour, that is to say, which does not require further rhodium plating treatments if the YI value is less than 19. Instead, if the YI value is between 19 and 24.5, the alloy belongs to the "standard white” category and a rhodium plating treatment may or may not be necessary depending on requirements. Finally, if the YI value is between 24.5 and 32, the white gold alloy belongs to the "off white” category and a final rhodium plating treatment is necessary.
  • white gold is produced by inserting in an alloy metals that have a whitening effect, that is to say, with the capacity to cancel out the typical yellow colour of gold.
  • the metal currently most used for this purpose is nickel, which as well as having high level whitening properties, is available on the market at a relatively low cost.
  • the core of the present invention consists of having identified gallium (in specific concentrations) as an innovative whitening element for making white gold alloys.
  • Gallium (whose chemical symbol is Ga, with atomic number 31 and atomic weight 69.7) is a silvery coloured metal, with a melting point of around 29.76°C. Its use for making jewellery is known. Thanks to its low melting point gallium is used to make solders. In some special applications gallium also gives alloys hardening properties.
  • gallium has extremely high level whitening properties, in line with what can normally be obtained using nickel and palladium.
  • the present invention is particularly important if one considers that the whitening effect is visible in particular at high karat weights, especially in 18 karat gold alloys.
  • additions of around 5 - 6% of gallium to 18 kt gold alloys allow a whitening intensity to be obtained which is comparable to that obtainable with similar concentrations of nickel.
  • the effect of melting temperature reduction allows a reduction in the casting temperature with consequent positive effects on precision casting with stones set in wax, zinc vaporisation and wear of the casting equipment.
  • the present invention may be applied both in the production of white gold alloy by simultaneously mixing all of the elements, and in the prior production of a master alloy intended to be mixed with the gold to obtain the white gold alloy only at a later stage.
  • the master alloy comprises all of the elements of which the gold alloy consists except gold, and therefore allows easy preparation of the white gold alloy by simply weighing and mixing the master alloy and the gold.
  • the present invention relates both to alloys which are free of nickel Ni only, and, in the preferred embodiment, alloys which are free of both nickel Ni and palladium Pd.
  • gallium as a whitening element is intended for the production of white gold alloys whose gold Au content, as a weight relative to the total weight of the white gold alloy, is within the range 31 % ⁇ Au ⁇ 92 %.
  • gallium Ga is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 1.4 % ⁇ Ga ⁇ 30.0 % or within the range 3 % ⁇ Ga ⁇ 30.0 %.
  • the gallium Ga is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 3.1 % ⁇ Ga ⁇ 12 %.
  • the gallium Ga is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 1,4 % ⁇ Ga ⁇ 20 % or within the range 3 % ⁇ Ga ⁇ 20 % (and in some cases greater than 6.1 %).
  • the gallium Ga is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 4 % ⁇ Ga ⁇ 20 %.
  • silver Ag is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Ag ⁇ 22.0 %.
  • silver Ag is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Ag ⁇ 40.1 % (eventually limited to 40,0 %), whilst in white gold alloys with a gold Au content, as a weight relative to the total weight of the white gold alloy, within the range 36 % ⁇ Au ⁇ 39 %, and preferably equal to 37.5 %, silver Ag is preferably used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Ag ⁇ 60.0 %.
  • Another improvement brought by the present invention is combining the use of gallium as a whitening element, assisted or not by silver, with the use of zinc Zn.
  • the Applicant found that adding zinc to gallium improves the white shade of the white gold alloy. It was ascertained that the addition of zinc allows the improvement of white alloys obtained by adding gallium, directing their shades of colour even more precisely towards a pure white colour.
  • Said result may generally be obtained by adding zinc Zn in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Zn ⁇ 30 %.
  • zinc Zn is used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Zn ⁇ 7 %.
  • zinc Zn is used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Zn ⁇ 21 %
  • zinc Zn is used in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0.01 % ⁇ Zn ⁇ 20 %.
  • said alloys may, in general, contain one or more of the following elements, where the quantities are always expressed as a weight relative to the total weight of the white gold alloy:
  • gallium is used as a whitening element in white gold alloys free of both nickel and palladium, in general it is also advantageously applied in all alloys which are free only of nickel.
  • palladium may be present in a quantity, as a weight relative to the total weight of the white gold alloy, within the range 0 % ⁇ Pd ⁇ 7.5 %.
  • gallium Ga is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 3.5 % ⁇ Ga ⁇ 80 % or within the range 6.4 % ⁇ Ga ⁇ 80 %.
  • gallium Ga is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 12.4 % ⁇ Ga ⁇ 48 %.
  • gallium Ga is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 3.5 % ⁇ Ga ⁇ 48.2 % or within the range 7.2 % ⁇ Ga ⁇ 48.2 %.
  • gallium Ga is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 6.4 % ⁇ Ga ⁇ 32 %.
  • silver Ag and zinc Zn may be present in quantities, as a weight relative to the total weight of the master alloy, respectively within the range 0.01 % ⁇ Ag ⁇ 96.5 % (eventually limited to 93.6 %) and the range 0 % ⁇ Zn ⁇ 60 %.
  • silver Ag is preferably used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Ag ⁇ 87.6 %, whilst zinc Zn is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Zn ⁇ 28 %.
  • silver Ag is preferably used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Ag ⁇ 96.5 % (eventually limited to 92.8 %)
  • zinc Zn is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Zn ⁇ 50.6 %.
  • silver Ag is preferably used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Ag ⁇ 93.6 % and zinc Zn is used in a quantity, as a weight relative to the total weight of the master alloy, within the range 0.01 % ⁇ Zn ⁇ 32 %.
  • the alloy consists, indicated above, with reference to the master alloy they may be present, as a weight relative to the total weight of the master alloy, in the following quantities:
  • the master alloy may be free of palladium Pd, or may contain palladium in a quantity, as a weight relative to the total weight of the master alloy, within the range 0 % ⁇ Pd ⁇ 30 %.
  • gallium may be used as a whitening element both in alloys which are free only of nickel, and in alloys which are also free of palladium, always giving excellent results.
  • a comparisone between the whiteness values of the conventional alloys and those disclosed by the invention allows the validity of gallium as a whitening element to be established.
  • compositions are expressed as weights in thousandths.
  • the three 750 (18 kt) gold alloy formulations have the same basic composition, but differ in terms of the gallium content (and, obviously, in a corresponding inverse fashion, the copper content, this being the element which completes the alloy).
  • the noticeable whitening effect which can be obtained by increasing the gallium concentration is clearly visible.
  • example 1.2.4 the formulation was changed compared with example 1.2.0, increasing the zinc content in the alloy by 87 %.
  • a comparison of the colour coordinates for the two formulations shows how the whitening effect of zinc is negligible.
  • silver was added to the previous formulation 1.2.4.
  • the silver contributed to further whitening of the alloy obtained, although to a noticeably lesser extent than can be obtained by adding similar quantities of gallium (see example 1.2.3).
  • gallium see example 1.2.3.
  • the present invention brings important advantages.
  • gallium is a safe element, since, although it has been used for many years in the goldsmith's sector, no cases of allergic contact dermatitis have ever been reported relative to it.
  • gallium like nickel and unlike palladium, is not a precious metal, therefore the cost linked to implementation of the invention is relatively limited.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Adornments (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Vehicle Step Arrangements And Article Storage (AREA)
EP08103100A 2007-09-27 2008-03-28 Juwelenlegierungen zur Herstellung von nickellosen Weißgoldobjekten Withdrawn EP2045343A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ITVR20070134 ITVR20070134A1 (it) 2007-09-27 2007-09-27 Leghe per oreficeria per la realizzazione di oggetti in oro bianco privi di nichel

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2322316A1 (de) * 2008-07-24 2011-05-18 Tanaka Kikinzoku Kogyo K.K. Au-ga-in-hartlötzusatzmetall
ITPD20130003A1 (it) * 2013-01-11 2014-07-12 Legor Group S P A Composizione di lega madre per la produzione di leghe di oro con innovativo sistema di affinatori e lega di oro ottenuta mediante tale composizione di lega madre
WO2014108848A1 (en) 2013-01-11 2014-07-17 Legor Group S.P.A. Master alloy composition for producing white gold alloys and white gold alloy thus obtained
CN104884650A (zh) * 2012-11-08 2015-09-02 贺利氏有限公司 具有低镍释放速率的含镍金合金、用于获得所述含镍金合金的中间合金以及其中金属元素的用途
WO2016151228A1 (fr) 2015-03-23 2016-09-29 Centre National De La Recherche Scientifique Alliage monophasique d'or et de tungstene
DE102015011788A1 (de) * 2015-09-16 2017-03-16 C. Hafner Gmbh + Co. Kg Weißgold-Legierung
EP3144401A1 (de) 2015-09-16 2017-03-22 C. Hafner GmbH + Co. KG Weissgold-legierung für ein schmuckstück
EP3165622A1 (de) * 2015-11-05 2017-05-10 Nivarox-FAR S.A. Herstellungsverfahren eines drahtes aus einer goldlegierung
WO2017143048A1 (en) * 2016-02-16 2017-08-24 Xtalic Corporation Articles including nickel-free coating and methods
RU2645423C1 (ru) * 2016-12-06 2018-02-21 Юлия Алексеевна Щепочкина Ювелирный сплав
CN113215431A (zh) * 2021-05-18 2021-08-06 沈阳东创贵金属材料有限公司 一种白k金靶材及其制备方法和应用
US11441210B2 (en) * 2019-08-23 2022-09-13 Omega Sa Timepiece or piece of jewellery or gemstone jewellery made of gold

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3414128A1 (de) 1984-04-14 1985-12-12 Heraeus Edelmetalle Gmbh, 6450 Hanau Farbgold-legierungen
EP0424775A1 (de) * 1989-10-27 1991-05-02 Degussa Aktiengesellschaft Lotlegierung für Dental- und Schmuckteile
US5045411A (en) * 1990-01-10 1991-09-03 P.M. Refining, Inc. Alloy compositions
DE4320928C1 (de) 1993-06-24 1994-03-17 Heraeus Kulzer Gmbh Gold-Schmucklegierungen und ihre Verwendung
DE4423646C1 (de) 1994-07-06 1995-08-17 Wieland Edelmetalle Nickelfreies Weißgold für Schmuckzwecke

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3414128A1 (de) 1984-04-14 1985-12-12 Heraeus Edelmetalle Gmbh, 6450 Hanau Farbgold-legierungen
EP0424775A1 (de) * 1989-10-27 1991-05-02 Degussa Aktiengesellschaft Lotlegierung für Dental- und Schmuckteile
US5045411A (en) * 1990-01-10 1991-09-03 P.M. Refining, Inc. Alloy compositions
DE4320928C1 (de) 1993-06-24 1994-03-17 Heraeus Kulzer Gmbh Gold-Schmucklegierungen und ihre Verwendung
DE4423646C1 (de) 1994-07-06 1995-08-17 Wieland Edelmetalle Nickelfreies Weißgold für Schmuckzwecke

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2322316A1 (de) * 2008-07-24 2011-05-18 Tanaka Kikinzoku Kogyo K.K. Au-ga-in-hartlötzusatzmetall
EP2322316A4 (de) * 2008-07-24 2012-02-01 Tanaka Precious Metal Ind Au-ga-in-hartlötzusatzmetall
CN104884650A (zh) * 2012-11-08 2015-09-02 贺利氏有限公司 具有低镍释放速率的含镍金合金、用于获得所述含镍金合金的中间合金以及其中金属元素的用途
ITPD20130003A1 (it) * 2013-01-11 2014-07-12 Legor Group S P A Composizione di lega madre per la produzione di leghe di oro con innovativo sistema di affinatori e lega di oro ottenuta mediante tale composizione di lega madre
WO2014108849A1 (en) * 2013-01-11 2014-07-17 Legor Group S.P.A. Master alloy composition for producing gold alloys and gold alloy
WO2014108848A1 (en) 2013-01-11 2014-07-17 Legor Group S.P.A. Master alloy composition for producing white gold alloys and white gold alloy thus obtained
WO2016151228A1 (fr) 2015-03-23 2016-09-29 Centre National De La Recherche Scientifique Alliage monophasique d'or et de tungstene
US10364481B2 (en) 2015-03-23 2019-07-30 Centre National De La Recherche Scientifique (Cnrs) Single-phase alloy of gold and tungsten
DE102015011788A1 (de) * 2015-09-16 2017-03-16 C. Hafner Gmbh + Co. Kg Weißgold-Legierung
EP3144401A1 (de) 2015-09-16 2017-03-22 C. Hafner GmbH + Co. KG Weissgold-legierung für ein schmuckstück
EP3165621A1 (de) * 2015-11-05 2017-05-10 Nivarox-FAR S.A. Herstellungsverfahren eines drahts aus goldlegierung
CN106676368A (zh) * 2015-11-05 2017-05-17 尼瓦洛克斯-法尔股份有限公司 金合金丝的制造方法
JP2017089002A (ja) * 2015-11-05 2017-05-25 ニヴァロックス−ファー ソシエテ アノニム 金合金線の製造方法
CN106676368B (zh) * 2015-11-05 2018-09-18 尼瓦洛克斯-法尔股份有限公司 金合金丝的制造方法
EP3165622A1 (de) * 2015-11-05 2017-05-10 Nivarox-FAR S.A. Herstellungsverfahren eines drahtes aus einer goldlegierung
US10471486B2 (en) 2015-11-05 2019-11-12 Nivarox-Far S.A. Method for fabrication of a gold alloy wire
WO2017143048A1 (en) * 2016-02-16 2017-08-24 Xtalic Corporation Articles including nickel-free coating and methods
RU2645423C1 (ru) * 2016-12-06 2018-02-21 Юлия Алексеевна Щепочкина Ювелирный сплав
US11441210B2 (en) * 2019-08-23 2022-09-13 Omega Sa Timepiece or piece of jewellery or gemstone jewellery made of gold
CN113215431A (zh) * 2021-05-18 2021-08-06 沈阳东创贵金属材料有限公司 一种白k金靶材及其制备方法和应用

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