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

• the invention relates to a platinum alloy and a process for its preparation. It particularly relates to a platinum alloy which is suitable for the production of jewelery articles such as rings, necklaces, bracelets, earrings, watch straps, watch cases and other jewelry. Furthermore, the invention relates to a made of the platinum alloy jewelry product and a method for its preparation.
• Platinum is a relatively expensive precious metal. In recent years, platinum has become increasingly popular as a material for jewelery production.
• the platinum alloys used for jewelry production usually have a platinum content of over 85 wt .-% on.
• Platinum alloys are because of their neutral color, though They are used together with gemstones, popular, they are hypoallergenic, have high tensile strength and due to their high density, a pleasant weight and a good feel.
• Pt950 platinum-t900
• Pt850 platinum-tindium
• PtCu950 95 wt .-% of platinum and 5 wt % Copper
• PtCo950 95 wt% platinum and 5 wt% cobalt
• high platinum content means a platinum alloy having a platinum content of 85% by weight or more.
• U.S. Patent 5,846,352 For example, a heat-treated platinum-gallium alloy for jewelery making containing 1 to 9 weight percent gallium and a small amount of palladium is described.
• an alloy for jewelry production which consists of 84 to 96 wt .-% platinum, 1 to 10 wt .-% gallium, 0.5 to 10 wt .-% copper and 0.01 to 5 wt .-% cobalt.
• An alloy for jewelery production is described which comprises 84 to 96% by weight of platinum, 0.5 to 10% by weight of cobalt, 0.5 to 10% by weight of copper and 0.01 to 0.5% by weight.
• % Y, B contains CaB misch metal.
• low platinum content means platinum alloys having a platinum content of less than 85% by weight.
• a disadvantage of known jewelry materials with low platinum content is that they often have inferior mechanical and physical properties compared to the jewelry materials with a high platinum content.
• the castability of the known low platinum content jewelry materials is not as good as that of the high platinum content alloys.
• the color of the known differs Low platinum content jewelry materials from the typical "platinum" color of Pt950 alloys desired by most fine jewelry customers. Therefore, jewelry materials with low platinum content are often rejected by customers for aesthetic reasons. In fact, it is very difficult to produce a low platinum content jewelry material combining both the mechanical strength and machinability and the optical properties of the high platinum content materials.
• an improved platinum alloy having a low platinum content which is 47.5 to
• the alloys according to the invention are particularly suitable for the production of jewelry articles such as rings, necklaces, necklaces and bangles, earrings, watch straps, watch cases and other jewelry, in particular embossed, stamped and deep-drawn jewelry as well as assembled and machined parts.
• the alloys according to the invention despite their relatively low platinum content, have excellent mechanical and optical properties and are outstandingly suitable for jewelery production. Due to the lower density of the alloys of the present invention, it is possible to produce thinner and lighter designs and castings at considerably lower cost than high platinum content alloys (eg, Pt850, Pt900, and Pt950) .
• the platinum alloys according to the invention have a lower melting range compared with known alloys having a low platinum content, as used, for example, in US Pat U.S. Patent 6,048,492 are described. Due to their relatively low melting temperature they are easier to cast than previously known platinum alloys and are more energy efficient. This lower melting temperature alloy also allows lower molding temperature and less scrap due to shrinkage porosity, cracks, inclusions, and contaminants that are more likely to occur at higher temperatures.
• platinum alloys according to the invention not only - as usual for known platinum alloys in the jewelry sector - can be cast in Kokillen- or vacuum casting, but also in continuous casting.
• the platinum alloys according to the invention are themselves suitable for the continuous casting of castings which have a casting cross section of greater than 100 mm 2 .
• the alloys according to the invention are particularly suitable for the production of jewelry because of their improved hardness, machinability, castability, deformability, wear and abrasion properties and corrosion resistance.
• the platinum alloy composition of the present invention looks and does not differ from 95% platinum, but is much lighter and less dense and thus cheaper to manufacture.
• the platinum alloy composition of the present invention has substantially the same color and appearance as the PtCu950 alloy.
• the invention further relates to a process for the preparation of the alloy according to the invention, in which the components thereof are formulated, mixed and melted together with the prescribed proportions.
• the alloy can be given the desired shape. Such operations are varied and include casting or machining. Some examples of machining include rolling the alloy into a sheet, drawing into a wire, molding, casting, Forging, pressing, stamping, forming or drawing to pieces of jewelry.
• the invention also relates to the use of these alloys in the manufacture of decorative products, such as jewelery. Moreover, the invention relates to jewelery products comprising these alloys.
• An object of the invention is to provide an improved platinum alloy composition of low platinum content.
• Another object of the invention is to provide an improved platinum alloy suitable for the mass production of jewelery articles.
• Another object of the invention is to provide an improved platinum alloy that has a lower density than known high platinum-content platinum alloys.
• the invention is further based on the object to provide a platinum alloy, which can be cast more easily than known platinum alloys and is particularly suitable for continuous casting.
• Another object of the invention is to provide an improved low-platinum alloy having a platinum weight percentage of 14 and 18 carats on a 24-carat scale.
• the platinum alloys according to the invention have a platinum content of 47.5 to 79.5% by weight, based on the total weight of the alloy.
• the platinum content of the alloy compositions according to the invention is significantly lower than the platinum content of the known platinum alloys Pt850, Pt900 and Pt950, which are commonly used in the jewelry industry.
• the platinum content of the alloy of the present invention may vary within the range given above. If the platinum content of the alloy is less than 47.5% by weight, the processability and corrosion properties of the alloy deteriorate significantly and the alloy loses its platinum-like color. If the platinum content of the alloy is more than 79.5% by weight, the cost of the alloy increases greatly, while at the same time the mechanical and chemical properties do not improve significantly.
• the palladium content of the alloy according to the invention is 2.01 to 25 wt .-%.
• the palladium content of the alloy is from 2.01 to 20, more preferably from 3 to 15, more preferably from 5 to 13, and most preferably from 8 to 12 weight percent, based on the total alloy composition. If the palladium content of the alloy is below 2.01 wt.%, Its corrosion properties deteriorate and the alloy loses its platinum-like color. If the palladium content of the alloy exceeds 25% by weight, the alloy becomes too expensive and the mechanical properties of the alloy deteriorate as a result of graphite uptake.
• the palladium content of the alloy may further be 0.5 to 25% by weight, in particular 0.5 to 20% by weight, preferably 0.5 to 15% by weight and more preferably 0.5 to 12.5 wt .-%, based on the total composition of the alloy.
• the alloy of the present invention may contain copper in an amount of 3 to 50.49% by weight based on the entire alloy composition.
• the alloy according to the invention preferably contains copper in an amount of greater than 5% by weight, in particular greater than 7.5% by weight, preferably greater than 10% by weight, more preferably greater than 12.5% by weight, even more preferably greater 15% by weight, even more preferably more than 17.5% by weight, even more preferably more than 20% by weight, even more preferably more than 22.5% by weight and most preferably more than 25% by weight.
• the above numerical values indicate the lower limit for the copper content in the alloy according to the invention.
• the upper limit for the copper content of the alloy according to the invention in% by weight can, according to a preferred Embodiment of the invention can be calculated by the following formula: 100 minus the sum of the remaining alloying components in wt .-%. According to a further preferred embodiment of the invention, the platinum alloy according to the invention in the rest of copper.
• the platinum alloy of the present invention may further contain 0.001 to 2% by weight of at least one first metal selected from the group consisting of iridium and ruthenium. Also, a combination of these elements may be added so long as the total amount does not exceed 2% by weight of the alloy composition.
• Iridium and / or ruthenium can be added as metal hardeners to increase the hardness of the alloy, with iridium being the preferred hardener because it provides gradual hardness improvements over a wide range of concentrations without degrading alloy properties.
• the platinum alloy of the present invention may further contain from 0.001 to 2% by weight of at least one second metal selected from the group consisting of indium and gallium. Also, a combination of these elements may be added so long as the total amount does not exceed 2% by weight of the alloy composition. Indium and gallium may be added to enhance precipitation hardening of the alloy.
• the alloy may further contain at least one property-improving additive.
• Known property-improving additives include, in particular, deoxidizers, particle size reducers, viscosity reducing agents or color modifiers.
• the number and proportion of other additives can vary depending on the desired mechanical properties of the alloy, and can be readily determined by one of ordinary skill in the art in light of routine experimentation.
• the alloy according to the invention has excellent mechanical and physical properties such as tensile strength, Vickers hardness and elongation at break.
• the tensile strength of the platinum alloy according to the invention is in the range of 250 to 900 N / mm 2 , in particular 450 to 800 N / mm 2 .
• the Vickers hardness of the platinum alloy according to the invention, measured in the uncured state, is in the range of 70 to 260 HV10, in particular 130 to 210 HV10.
• the elongation at break of the platinum alloy according to the invention is at least about 15%, in particular at least about 20%.
• Another advantage of the present invention is that the hue of the platinum alloy substantially matches the platinum white hue of the PtCu950 alloy, which is aesthetically pleasing.
• the alloy according to the invention may further comprise one or more base metals in an amount of 0.01 to 15 wt .-%, in particular 0.01 to 10 wt .-%, preferably 0.1 to 7.5 wt .-%, and am most preferably 0.5 to 5 wt .-%.
• non-noble metal means a metal that does not belong to the group of noble metals (gold, silver, mercury, rhenium, ruthenium, rhodium, palladium, osmium, iridium, and platinum).
• Non-precious metals which may be present in the alloy according to the invention are, for example, copper, iron, cobalt, nickel, indium and / or gallium.
• the phrase "consists essentially of” means that it includes all of the alloying ingredients except for common impurities and property-improving additives such as hardeners (eg, iridium and / or ruthenium), deoxidizers, grain size reducers, viscosity lowering agents, or color modifiers ,
• the total proportion of the property-improving agents is preferably less than 5 wt .-%, more preferably less than 3 wt .-%, more preferably less than 2 wt .-%, more preferably less than 1 wt .-%, and most preferably less as 0.5% by weight.
• the platinum alloy according to the invention can be present in the crystalline or in the amorphous state.
• the platinum alloy of the present invention is in a substantially crystalline state.
• the phrase "substantially crystalline state” means that the platinum alloy is greater than about 50% by volume in the crystalline state.
• the platinum alloy is at least about 90 volume percent, more preferably at least about 95 volume percent, and most preferably about 100% in the crystalline state.
• the alloy of the invention is also preferably non-ductile.
• the alloy of the invention is preferably substantially free of nickel, chromium, phosphorus and / or cobalt.
• the amount of the aforementioned elements in the alloy is in each case less than 5 wt .-%, in particular less than 3 wt .-%, preferably less than 2 wt .-%, more preferably less than 1 wt. -%, and most preferably less than 0.5 wt .-%, based on the total composition of the alloy.
• the alloy of the invention can be prepared by conventional alloying processes known in the art.
• the preparation of the alloy generally comprises the step of melting platinum, palladium and copper and optionally further alloying constituents in the corresponding proportions.
• the method may further comprise the step of curing the alloy by cold working or heat treatment.
• the method may further include the steps of annealing and then quenching the alloy prior to curing.
• the alloy is usually cast from a melt under inert gas and then molded. After shaping, the alloy may be subjected to a heat treatment, optionally under protective gas, in order to improve its mechanical properties.
• the preparation of the platinum alloy according to the invention is preferably carried out by high-temperature melting, for example by induction. Care should be taken to limit any contamination of the alloy, since platinum is easily contaminated with environmental elements (air, crucibles, etc.). It is therefore advisable to melt the metals either in a vacuum or under an inert gas atmosphere, whereby contact with other metals and mixing with SiO 2 -containing products should be prevented.
• the platinum alloy is preferably mixed and melted by induction heating in a crucible suitable for platinum alloys. After melting, the alloy may be poured into water to produce granules and then dried, weighed and used for casting.
• the components of the composition of the invention are preferably melted in a silica crucible (for small, rapid melts) or a zirconia crucible (for large, slow melts) in an induction furnace. It is preferred to use a vacuum or inert gas in the melting process and to add all components of the alloy composition at the same time in the crucible.
• the molten metals should preferably be "turned" (using medium to low frequency induction fields) to achieve proper intermixing of the metals.
• the obtained granular alloying components may be cold rolled and / or annealed to improve the mechanical properties of the mixture. Thereafter, the mixed metal composition may optionally be remelted as before and a shot or sheet made.
• the preparation of the platinum alloy according to the invention may further comprise an annealing step.
• the annealing may be performed either in an oven or in a flame as known in the art.
• the annealing temperature depends on the platinum content and the melting point of the alloy and can easily be determined by one of ordinary skill in the art in the context of routine experiments.
• the annealing is carried out in an oven under a protective gas atmosphere.
• the shielding gas may be any of the non-oxidizing inert gases such as argon, nitrogen or a mixture thereof, antioxidant gases such as hydrogen and carbon monoxide or "forming gas” or “split ammonia” (nitrogen with a few percent hydrogen).
• the workpiece can also be protected from oxidation by surrounding it with commercially available heat-treating sleeves.
• the alloy can be used for a wide variety of jewelry components such as rings, buckles, spring parts, compression spring mountings for gemstones, and the like.
• the alloy may be repeatedly annealed and heat treated / cured.
• curing is essentially synonymous with the term “precipitation hardening” which results from the formation of minute particles of a novel constituent (phases) in a solid solution. The presence of these particles creates stress in the alloy and increases its yield strength and hardness. See for example BA Rogers, “The Nature of Metals,” p. 320 (Iowa State University Press, 1964 ) HW Polock, “Materials Science and Metallurgy", p.266 (Reston Pub. Inc., 1981 ) and " The Metals Handbook, p. 1-2 (Am. Soc'y Metals, 1986 ).
• the alloy in the annealed / uncured state, can be processed by standard jewelery manufacturing techniques. For example, it can be rolled, drawn, soldered, shaped, bent, lasered, pressed and punched.
• the alloy can be used for a variety of designs for springs, gemstone casings in rings, pendants, bracelets, necklaces, precious metal craft items, and the like.
• bodies in particular jewelry, of any size and shape can be produced.
• the basic shapes of bodies can vary from a simple sheet to ring shapes and more complex screw shapes, V shapes, and the like.
• the bodies may be a wire, a sheet, a spring of any kind, pendants, chain links, brooches, etc. It can be used in the jewelry industry standard soldering or laser process.
• the alloy can be shaped, bent, assembled and annealed, and when the piece is finished, spring force and hardness can be restored by a heat treatment.
• the jewelry product can also be produced by casting, in particular by mold or vacuum casting, but also by continuous casting.
• the alloy hardness can be further increased by a heat treatment.
• the heat treatment may be performed in a range of 300 to 950 ° C, with a suitable value in the range of 600 to 950 ° C, and typically about 800 ° C.
• the alloy may be annealed by standard annealing procedures, typically at about 850 to 950 ° C.
• the alloy may be used in the form of wire, sheet or other machined article, and due to its high hardness, along with great ductility, it may be given intricate shapes and shapes.
• the alloy according to the invention can be used, for example, for the production of wedding rings. These are generally made by cutting blanks out of pipes and working them through suitable operations such as milling, drawing, forging and polishing.
• the alloys of the invention are characterized by good castability, which offers the opportunity for use in the entire field of jewelry casting. Due to its good ductility, the alloy is excellently suited for the production of rings and chains, embossed, pressed, stamped and deep-drawn jewelery, as well as for assembled and machined parts. In addition, the alloy is very easy to polish, frames can also be performed well. For the joining technique, the material is good solderable and very good with lasers. Finally, the alloys of the invention with the tools of the goldsmith after a heat treatment with partial oxidation of the copper content are easily accessible.
• a 585PtPd100Cu type alloy having the composition shown in the following table was weighed and melted under vacuum in a ZrO 2 crucible in a vacuum induction furnace at a temperature of 1520 to 1560 ° C to obtain a homogeneous melt.
• the alloy was poured into a water-cooled copper mold to form bars measuring 20 mm x 145 x 200 mm. After a reduction in thickness of 75% by cold rolling, the alloy was annealed at 950 ° C under a nitrogen atmosphere.
• the physical properties of the prepared alloy samples are shown in the table.
• the melting range was determined by measuring the cooling curve of the alloy with a Degussa resistance furnace HR1 / Pt / PtRH10 equipped with a Linsenis thermocouple and a temperature-time plotter L250.
• the Vickers hardness was measured according to EN ISO 14577 using a Wolpert V-Testor 4521 device.
• Tensile strength, elongation at break and yield strength were determined in accordance with EN 10002 using a Zwick Z010 device. The color was determined visually.
• An alloy of the type 75OPtPd100Cu with the composition given in the table was prepared according to the procedure given in Example 1, the alloy being at a temperature of 1680 to 1740 ° C was melted.
• the physical properties of the prepared alloy samples were determined as in Example 1 and are summarized in the table.
• a commercially available alloy of Pt / Cu 950/50 was weighed out and melted under vacuum in a ZrO 2 crucible in a vacuum induction furnace, wherein a homogeneous melt was obtained.
• the alloy was poured into a water-cooled copper mold to form bars measuring 20 mm x 145 x 200 mm. After a reduction in thickness to 10 mm by cold rolling, the alloy was annealed for 50 minutes at 1000 ° C under a nitrogen atmosphere. The next deformation steps were 4 mm and 1.0 mm. Between these steps, the material was annealed at 1000 ° C.
• a 585PtCuCo type alloy having the composition shown in the table was weighed and melted under vacuum in a ZrO 2 crucible in a vacuum induction furnace at a temperature of 1480 to 1500 ° C to obtain a homogeneous melt.
• the alloy was poured into a water-cooled copper mold, with bars of dimensions 20 mm x 145 x 200 mm were formed. After a reduction in thickness of 75% by cold rolling, the alloy was annealed at 950 ° C under a nitrogen atmosphere.
• Example 1 The physical properties of the prepared alloy samples were investigated as described in Example 1 and are shown in the table.
• ⁇ U> Table ⁇ / u> Example 1 585ptpd100Cu
• Example 2 750PtPd100Cu Comparative
• Example 1 585PtCuCo Comparative
• Example 2 950PtCu composition Pt 58.5% by weight Pt 75.0% by weight Pt 58.6% by weight Pt 95% by weight Pd 10.0% by weight Pd 10.0% by weight Pd 10.0% by weight Cu 37.3% by weight Cu 5% by weight Cu 31.5% by weight Cu 15.0% by weight Co 4.1% by weight density 14.2 16.7 13.6 20.3 colour platinum white platinum white platinum white platinum white melting interval 1310-1380 1550-1600 1360 - 1410 1730 - 1745 Castability (jewelery casting) excellent excellent well suited suitable Hardness [HV] annealed 180 180 170 110 20% cold rolled 230 242 260 185 40% cold rolled 250 263 285 210 60% cold rolled
• the test results show that the alloy according to the invention has superior casting, wear and abrasion properties compared with the known alloy Pt / Cu 950/50 . Furthermore, the experimental results show that the shaping properties and hue of the alloy according to the invention are similar to those of the known alloy Pt / comparable Cu 950/50.
• the alloys are characterized by good castability, which offers the opportunity for use in the entire field of jewelery casting. Due to its good ductility, the alloy is excellently suited for the production of rings and chains, embossed, pressed, stamped and deep-drawn jewelery, as well as for assembled and machined parts. In addition, the alloy is very easy to polish, frames can also be performed well. For the joining technique, the material is good solderable and very good with lasers. Finally, the alloys of the invention with the tools of the goldsmith after a heat treatment with partial oxidation of the copper content are easily accessible.

Landscapes

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=37985361

Family Applications (1)

Country Status (2)

Cited By (2)

Families Citing this family (5)

Citations (6)

Family Cites Families (7)

• 2006
  • 2006-02-16 DE DE102006007556A patent/DE102006007556A1/de not_active Withdrawn
• 2007
  • 2007-02-12 DE DE202007018831U patent/DE202007018831U1/de not_active Expired - Lifetime
  • 2007-02-12 EP EP07102132A patent/EP1820867A1/fr not_active Withdrawn
  • 2007-02-12 DE DE202007018312U patent/DE202007018312U1/de not_active Expired - Lifetime

Patent Citations (7)

Also Published As

Similar Documents

Legal Events