Classifications

• • 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
  • C22C5/00—Alloys based on noble metals
  • C22C5/04—Alloys based on a platinum group metal

Definitions

• alloys previously used had the special mechanical, physical and chemical properties that are required of such alloys for jewelry purposes.
• Such metals have to be easily deformable in order to turn sheet, wire and tube into them
• they must have a minimum stability, for example for the production of delicate jewelry or watch straps, and they must also be available in sufficient hardness with sufficient elongation at break.
• the alloys for the production of castings must be readily castable, that is to say that in addition to good flowability, they must also have high oxidation resistance in the molten state.
• Common to all alloys for jewelry purposes, but especially the gold and platinum alloys is that they are to a high degree resistant to tarnishing even when worn for a long time.
• jewelry alloys should also be available in the well-known jewelry alloy colors, which can be varied between white, yellow and red shades.
• the invention specifies alloys which are considerably cheaper than the gold and platinum alloys used hitherto, but which, if appropriate with different alloy additives, all meet the above-mentioned requirements placed on such alloys for jewelry purposes.
• a first alloy of this type consists of 75% by weight to 99.5% by weight of palladium as the base metal, with additions of metals from the 3rd to 6th period of the periodic system of the elements;
• a second cheaper alloy consists of 75 wt.% to 99.5 wt.% of a base alloy of 25 wt.% to 75 wt.% palladium, 10 wt 70% by weight of silver and 5% by weight to 50% by weight of copper, likewise again with additions of metals from the 3rd to 6th period of the periodic system of the elements.
• the palladium in these alloys is the metal that replaces the corrosion-resistant metals gold and platinum.
• the palladium is the alloy metal which imparts the properties to the alloy according to the invention in order to make it useful for jewelry purposes.
• the additional metals of the 3rd to 6th period of the periodic system of the elements give this base metal or this base alloy the properties desired in each case. Additions of chromium, manganese, iron, cobalt and nickel result in very good tarnish resistance and a platinum-like light gray color, while additions of copper, silver and gold are particularly easy to deform cold and are excellent for soldering.
• Additions of titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten and rhenium give this alloy excellent anal resistance. Additions of ruthenium, rhodium, iridium or platinum behave in a similar way. Additions of zinc, gallium, germanium, indium, tin, antimony or bismuth give the alloy very good castability and high hardness.
• German laid-open specification 33 04 598 "Alloy based on palladium” also describes an alloy for the manufacture of jewelry, but with a palladium content of 48 to 61% by weight a content of 12% to 51% by weight is mandatory.
• Indium prescribed that this alloy should give an increased breaking strength and a relatively low melting temperature.
• this alloy was not able to establish itself in the manufacture of jewelry, since a multi-phase structure is formed due to the high indium content.
• the processing of this alloy by non-cutting deformation that is to say for the production of sheet metal, wire and tube, is not possible.
• Another significant disadvantage is the increased inability to corrosion due to the inhomogeneous structure.
• the alloy described, on the other hand even if it should contain small amounts of indium, does not suffer from these disadvantages, but rather fulfills to a large extent the requirements specified above for such an alloy.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Adornments (AREA)

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Cited By (13)

Citations (7)

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• 1986
  • 1986-11-13 EP EP86115798A patent/EP0267318A3/fr not_active Ceased

Patent Citations (7)

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