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
• • A—HUMAN NECESSITIES
  • A44—HABERDASHERY; JEWELLERY
  • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
  • A44C27/00—Making jewellery or other personal adornments
  • A44C27/001—Materials for manufacturing jewellery
  • A44C27/002—Metallic materials
  • A44C27/003—Metallic alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/02—Making non-ferrous alloys by melting
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/14—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of noble metals or alloys based thereon
• • A—HUMAN NECESSITIES
  • A44—HABERDASHERY; JEWELLERY
  • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
  • A44C5/00—Bracelets; Wrist-watch straps; Fastenings for bracelets or wrist-watch straps
• • A—HUMAN NECESSITIES
  • A44—HABERDASHERY; JEWELLERY
  • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
  • A44C5/00—Bracelets; Wrist-watch straps; Fastenings for bracelets or wrist-watch straps
  • A44C5/18—Fasteners for straps, chains or the like

Definitions

• the present invention relates to an alloy of gray gold without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and without manganese.
• the invention also relates to a timepiece, a jewelery item comprising at least one component produced with such an alloy.
• gray gold alloys There are mainly two kinds of gray gold alloys on the market, alloys in which the metal for bleaching gold is nickel and those in which this metal is palladium.
• nickel alloys are still used less because of their allergenic properties in contact with the skin, which leads to excluding them from watchmaking clothing for external components. Therefore palladium alloys are used for this function.
• Gray gold alloys intended for use in the watchmaking and jewelry fields must meet two constraints relating on the one hand to their brightness and whiteness and on the other hand to their capacity for deformation. For this, they must have a color and a sheen of pure whiteness as well as excellent ductility and corrosion resistance. More particularly, the gray gold alloys sought must have values according to the chromatic model La * b * (CIE 1976) such that L ⁇ 80, a * ⁇ 1.5 and b * ⁇ 7, preferably b * ⁇ 6, and preferably b * ⁇ 5, as well as a hardness HV of between 140 Hv and 225 Hv, the lowest values being the most favorable to the deformation.
• La * b * CIE 1976
• these alloys necessarily have a high palladium content, which limits their mechanical properties.
• rhodium plating is often used to improve the color and reflectivity of the alloys, in order to promote the shine of the stones when the alloys are set.
• This rhodium plating operation has a major long-term drawback because the layer of rhodium deposited of the order of 1 to 5 microns always ends up wearing out. Consequently, the after-sales service is faced with an expensive re-dressing operation, due to the need to mask the color difference between the alloy and the rhodium improvement layer.
• the patent EP 1 010 768 relates to 18-carat white gold alloys with a palladium content of between 12 and 14%, and also comprising copper, which gives chromatic values in the L, a *, b * system such as 1.8 ⁇ a * ⁇ 2.3 and 7 ⁇ b * ⁇ 10.
• the patent EP 1 227 166 refers to 18 carat white gold alloys without palladium, and comprising copper and manganese, which gives chromatic values in the L, a *, b * system such as 2.6 ⁇ a * ⁇ 6 and 10 ⁇ b * ⁇ 13.
• the patent EP 1,245,688 relates to 18-carat white gold alloys with a palladium content of between 5 and 7%, also comprising copper and silver, which gives chromatic values in the L, a *, b * system that 1.5 ⁇ a * ⁇ 4.5 and 10.5 ⁇ b * ⁇ 15.2.
• EP 2,546,371 A1 refers to 18 carat white gold alloys with a palladium content between 2 and 12% and a chromium content between 13 and 23 %, which gives chromatic values in the L, a *, b * system such as 0.25 ⁇ a * ⁇ 0.7 and 3 ⁇ b * ⁇ 4.2.
• the patent EP 2,427,582 B1 refers to 18-carat white gold alloys with a palladium content between 18 and 24% and a content of various elements including Zr, Nb or Mn between 1 and 6%, which gives chromatic values in the system L, a *, b * such that 1.1 ⁇ a * ⁇ 1.5 and 4.5 ⁇ b * ⁇ 5.7.
• the patent application EP 3070182 A1 refers to a gray gold alloy without nickel, without cobalt, without iron, without silver, without copper, without zirconium, without niobium, without chromium and without manganese, comprising, expressed by weight, from 75.0 to 76.5 % of Au, 15 to 23% of Pd, 0.5 to 5% of Rh, 0 to 7% of Pt, and 0 to 5% of at least one of the addition elements Ir, Ru, Ti , In, Ga, B and Re, the respective percentages of all the elements of the alloy complementing up to 100%.
• This alloy by virtue of its precious metal content, can only be exclusively dedicated to the manufacture of components for fine jewelry.
• the present invention therefore aims to substantially improve gray gold alloys by providing a gray gold alloy without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and manganese-free, eliminating rhodium plating without reducing its deformability properties.
• the object of the present invention is therefore to substantially improve gray gold alloys by providing a nickel-free gray gold alloy without cobalt, iron-free, silver-free, zirconium-free, niobium-free, chromium-free, indium-free, gallium-free and manganese-free whose deformability allows its transformation by cold rolling and drawing techniques without risk of cracking and which is economical to achieve.
• Another object of the present invention is to provide an alloy of gray gold without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and without manganese presenting an interesting compromise between a color, a brightness of whiteness sufficient to meet the aesthetic requirements of the field of watchmaking, thus avoiding a rhodium plating operation.
• Another object of the present invention is to provide an alloy of gray gold without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and without manganese which can be easily polished and very white after polishing.
• Another object of the present invention is to provide an alloy of gray gold without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and without manganese with costs of weaker elaboration.
• the present invention relates to an alloy of gray gold without nickel, without cobalt, without iron, without silver, without zirconium, without niobium, without chromium, without indium, without gallium and without manganese, comprising, expressed in weight, from 75.0 to 76.5% of Au, from 15 to 23% of Pd, from 1 to 7% of Cu, and from 0 to 5% of at least one of the addition elements Ir, Ru, B and Re , the respective percentages of all the elements of the alloy complementing up to 100%.
• the present invention also relates to a timepiece, a jewelery item comprising at least one component made of an alloy as defined above.
• This component is for example a watch case, a dial, a bracelet, a bracelet clasp, a piece of jewelry, or an accessory.
• the present invention also relates to the use of an alloy as defined above in a timepiece, of jewelry or of fine jewelry.
• the alloy of the present invention is a gray gold alloy, nickel free, cobalt free, iron free, silver free, indium free, gallium free, manganese free, zirconium free, chrome free, and niobium free.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% of Au, from 15 to 23% of Pd, from 1 to 7% of Cu , and from 0 to 5% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all of the elements of the alloy complementing up to 100%.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% of Au, from 17 to 22.5% of Pd, from 2 to 7% of Cu and from 0 to 5% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all of the elements of the alloy complementing up to 100%.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% of Au, from 18 to 22.5% of Pd, from 2 to 6.5% of Cu , and from 0 to 4% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all the elements of the alloy complementing up to 100%.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% Au, from 18.5 to 22% Pd, 2.5 to 6.5% Cu and 0 to 3% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all the elements of the alloy are supplementing up to 100%.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% of Au, from 18.5 to 21.5% of Pd, from 3 to 6% of Cu , and from 0 to 2.5% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all the elements of the alloy complementing up to 100%.
• the gold alloy is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% of Au, from 19 to 21% of Pd, from 3.5 to 5.5% of Cu , and from 0 to 1.8% of at least one of the addition elements Ir, Ru, B and Re, the respective percentages of all of the elements of the alloy complementing up to 100%.
• the gold alloy can also be rhodium-free.
• the gold alloy can comprise at least one of the elements Ir, B, in a proportion for each element of between 0.002 and 1% by weight.
• the proportion of B is preferably between 0.002 and 0.2%, and more preferably between 0.08 and 0.2%.
• the proportion of Ir is preferably between 0.002 and 0.13% by weight.
• the proportion of Re is preferably between 0.001 and 0.05% by weight, and preferably between 0.001 and 0.002% by weight .
• the proportion of Ru is preferably between 0.002 and 1% by weight, and more preferentially between 0.008 and 0.015% by weight .
• the gold alloy according to the invention is an 18-carat alloy and comprises, expressed by weight, from 75.0 to 76.5% Au, from 19 to 21% Pd, from 3.5 to 5.5 % of Cu, and from 0.08 to 0.2% of B, the respective percentages of all the elements of the alloy complementing up to 100%.
• the gold alloys according to the invention find a particular application for the production of timepieces for jewelery or fine jewelry.
• this alloy makes it possible in particular to avoid the galvanic deposition of rhodium which is commonly used in the watchmaking and jeweler field to give the treated parts a shine and a color of satisfactory whiteness.
• the main elements used in the composition of the alloy have a purity between 999 and 999.9 per thousand and are deoxidized.
• the elements of the composition of the alloy are placed in a crucible which is heated until the elements are melted.
• the heating is carried out in a sealed induction furnace under partial nitrogen pressure.
• the molten alloy is poured into an ingot mold.
• the ingot After solidification, the ingot is subjected to water quenching.
• the hardened ingot is then cold rolled and then annealed.
• the rate of work hardening between each annealing is from 66 to 80%.
• Each annealing lasts 20 to 30 minutes and is carried out at 900 ° C under a reducing atmosphere composed of N 2 and H 2 .
• Cooling between anneals is done by quenching with water.
• Table 4 below shows different properties of the alloys obtained according to Examples No. 1 to No. 5 of Table 1.
• Table 4 gives in particular the indications relating to the Vickers hardness of the alloy in the annealed state, as well as those of the color measured in a coordinate system with three axes.
• the 18-carat white gold alloys of the invention (examples 4 and 5) were developed and tested in deformation to meet the triple brightness / whiteness constraint, deformation capacity and production cost required for alloys intended for use in the watchmaking and jewelry sector.
• the alloys therefore have chromatic values such as L ⁇ 80, a * ⁇ 1.5 and b * ⁇ 5.5, a hardness between 140 Hv and 225 Hv, and preferably between 140 Hv and 180 Hv, as well as at a reduced production cost.
• alloys of the prior art and comparative examples do not make it possible to respond to this triple constraint.

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• Chemical & Material Sciences (AREA)
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• 2016
  • 2016-12-20 EP EP16205419.1A patent/EP3339455B1/fr active Active
• 2017
  • 2017-11-28 US US15/824,344 patent/US10458002B2/en active Active
  • 2017-12-13 JP JP2017238323A patent/JP6740204B2/ja active Active
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