JP2009515034A - Platinum alloy and method for producing the same - Google Patents

Abstract

The disclosure relates to a platinum alloy comprising (a) 63.01 to 69.99 wt. % of platinum, (b) 1.5 to 10 wt. % of cobalt, and (c) 20.01 to 35.49 wt. % of copper. The platinum alloys have excellent mechanical and optical properties for use in the production of ornamental articles such as rings, necklaces, earrings, watch bands, watch bodies and other jewelry. The disclosure further relates to a method of preparing the platinum alloys and their use in the production of ornamental articles. Still further the disclosure relates to ornamental articles comprising the platinum alloy and a method of production thereof.

Description

  The present invention relates to a platinum alloy and a method for producing the same. In particular, the present invention relates to a platinum alloy suitable for the manufacture of ornaments such as rings, necklaces, bracelets, earrings, watch bands, watch bodies, and other jewelry. Furthermore, the present invention relates to a decorative article made from the platinum alloy and a method for producing the same.

  Platinum is a noble metal and is relatively expensive. In recent years, platinum has become increasingly prominent as a metal used in the manufacture of jewelry. Platinum for fine jewelry is generally sold at a high concentration exceeding 85% by mass.

  Pure platinum metal (Pt1000) is soft and does not have mechanical strength for most gemstone applications. For this reason, various platinum alloys are used in most gemstone applications. Platinum alloys are preferred because of their neutral color when combined with gemstones, platinum alloys are hypoallergenic, and due to the high density of platinum alloys, platinum alloys have high tensile strength and pleasant weight This is preferable.

  The jewelry industry uses three main types of platinum alloys. The three main types are Pt950, Pt900 and Pt850. The platinum contents of these alloys are 95%, 90% and 85% by weight, respectively. Commercial alloys that are often used in the manufacture of jewelry are Pt / Ir900 / 100 (90 wt% platinum and 10 wt% iridium), PtCu950 (95 wt% platinum and 5 wt% copper) and PtCo950 ( 95% platinum and 5% cobalt).

  Various high platinum content gem materials are known in the art. As used herein, “high platinum content” refers to a platinum alloy having a platinum content of 85% by weight or more.

  For example, U.S. Pat. No. 4,165,983 describes an alloy used in the manufacture of jewelry. The alloy is selected from the group consisting of at least 95% by weight platinum, 1.5-3.5% by weight gallium, and the balance being indium, gold, palladium, silver, copper, cobalt, nickel, ruthenium, iridium and rhodium. Including at least one kind. U.S. Pat. No. 5,846,352 describes a heat treated platinum-gallium alloy. The alloy contains 1-9% by weight gallium and a small amount of palladium and is used in the manufacture of jewelry. JP 61-133340 describes an alloy used for the manufacture of jewelry. The alloy consists of 84% to 96% platinum, 1% to 10% gallium, 0.5% to 10% copper, and 0.01% to 5% cobalt. . JP 61-034133 describes an alloy used for the manufacture of jewelry. The alloy consists of 84% to 96% platinum, 0.5% to 10% cobalt, 0.5% to 10% copper, and 0.01 to 0.5 Y, B. And CaB misch metal.

  Although the alloys described above have sufficient mechanical and optical properties suitable for the manufacture of jewelry, these alloys are expensive to manufacture due to their high platinum content.

  Thus, a large number of gem materials with a low platinum content are known in the art. As used herein, “low platinum content” refers to a platinum alloy having a platinum content of less than 85% by weight.

  U.S. Pat. No. 6,048,492 describes platinum alloy compositions for use in jewelry products. The alloy composition includes about 58.5 wt% platinum, 26.5 wt% to 36.5 wt% palladium and 5 wt% to 15 wt% iridium, copper or ruthenium. U.S. Pat. No. 2,279,763 describes a ductile platinum alloy comprising 10% to 80% by weight platinum, 12% to 90% by weight palladium and 1% to 15% by weight ruthenium.

  WO 2004/059019 A1 (WO 2004/059019 A1) describes PT-based bulk solidified amorphous alloys that utilize platinum and other components and require the presence of phosphorus. The amorphous alloy described in this document is manufactured by quenching a molten alloy from a temperature equal to or higher than the melting point to room temperature. This treatment yields a solid (ie, non-crystalline) alloy and more than 50% is in an amorphous state.

  Known gem materials with a low platinum content are disadvantageous in that they may have poor mechanical and physical properties compared to gem materials with a high platinum content. In particular, the castability of a known gem material with a low platinum content is not equivalent to the castability of a gem material with a high platinum content. Also, the color of known gem materials with low platinum content is different from the general 'platinum color' of Pt950 alloy that most customers of fine jewelry demand. Thereby, jewelry materials with a low platinum content may not be accepted by customers for aesthetic reasons. In fact, it is extremely difficult to produce a gem material with a low platinum content that has both mechanical strength and processability and optical properties equivalent to a material with a high platinum content.

  Due to the potential for improvements in the performance and properties of such alloys, there is a need for alloys suitable for use in jewelry and art.

  Therefore, there is a need to provide a platinum alloy composition that is cheaper than currently available platinum and suitable for jewelry, and further to provide a platinum jewelry product having the technical and optical properties required for jewelry. Yes.

  The present invention provides an improved alloy composition with a low platinum content. The alloy composition of the present invention includes 63.01 mass% to 69.99 mass% platinum, 1.5 mass% to 10 mass% cobalt, and 20.01 mass% to 35.49 mass% copper. The alloys of the present invention are particularly suitable for producing decorative articles such as rings, necklaces, earrings, watch bands, watch bodies and other jewelry.

  Surprisingly, the alloys of the present invention exhibit good mechanical and optical properties despite the relatively low platinum content, which makes the alloys of the invention produce decorative articles such as jewelry. Therefore, it can be particularly preferably used. Thinner and lighter structures and castings at significantly lower costs compared to high platinum content alloys (eg, Pt850, Pt900, Pt950) due to the low density of the alloys of the present invention Can be manufactured.

  The platinum alloy of the present invention has a lower melting range compared to the known low platinum content alloys described, for example, in US Pat. No. 6,048,492. Due to the relatively low melting point, the platinum alloys of the present invention are easier to cast and more energy efficient than previously known platinum alloys. Also, such a low temperature alloy can lower the mold temperature, thereby reducing the defect rate due to shrinkage holes, investment cracking, inclusions, and contaminants that easily occur under high temperature conditions.

  The alloys of the present invention are particularly suitable for the manufacture of jewelry due to their improved hardness, workability, castability, deformability, wear and wear properties, and corrosion resistance. Although the platinum alloy composition of the present invention appears or appears to contain 95% by weight of platinum, it is sufficiently light and has a low density, so it is inexpensive to manufacture. Indeed, 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 production of an alloy according to the invention by formulating and mixing the components of the alloy in specific amounts and melting them together.

  The alloy may be formed into a desired shape. Such operations are numerous and include casting or secondary processing. Some examples of processing include extending the alloy into a sheet, drawing the wire, forming it into a useful object or shape as a gem component, casting, forging, stamping, or assembling. It is done.

  Therefore, the present invention relates to a method for manufacturing a decorative article, in which any one of the platinum alloys described above is manufactured and then the alloy is used as a jewelry part.

  Furthermore, the present invention relates to a method of using such an alloy in the manufacture of ornaments such as jewelry. The invention further relates to a decorative article comprising such an alloy.

  Accordingly, it is an object of the present invention to provide an improved platinum alloy composition having a low platinum content.

  Another object of the present invention is to provide an improved platinum alloy composition suitable for use in the large scale commercial market of gems.

  Yet another object of the present invention is to provide an improved platinum alloy composition that is lighter and less dense than conventional platinum alloy compositions.

  Furthermore, the objective of this invention is providing the platinum alloy which can be casted easily compared with a well-known platinum alloy.

  Still other objects and advantages of the present invention will be in part apparent from the above description, and will become apparent from the following description.

  The platinum alloy composition of the present invention contains platinum in an amount of 63.01% by mass to 69.99% by mass. The platinum content in the alloy composition of the present invention is significantly lower than the platinum content of conventional Pt850, Pt900 and Pt950 commonly used in the jewelry industry.

  According to one embodiment of the present invention, the platinum alloy includes the following components: 63.01 wt% to 69.99 wt% platinum; 1.5 wt% to 10 wt% cobalt, and 22.01. % By weight to 35.49% by weight of copper.

  The platinum content of such an alloy is preferably 63.5% by mass to 66.5% by mass, and more preferably 64% by mass to 66% by mass with respect to the entire alloy composition. If the platinum content of the alloy is less than approximately 63% by weight, the workability and punchability (stampability) of the alloy is greatly reduced, and the alloy impairs its platinum-like color. If the platinum content of the alloy exceeds approximately 70% by weight, the mechanical and chemical properties of the alloy are not significantly improved, although the manufacturing cost of the alloy is significantly increased.

  The cobalt content in the alloy of the present invention is 1.5% by mass to 10% by mass, particularly 2% by mass to 8% by mass or 2% by mass to 6% by mass, based on the entire alloy composition. Is preferred. If the cobalt content of the alloy is less than approximately 1.5% by weight, the mechanical properties and workability of the alloy are greatly reduced and the alloy impairs its platinum-like color. If the cobalt content of the alloy exceeds approximately 8% by weight, the alloy becomes significantly harder.

  The other component in the alloy of the present invention is preferably copper.

  The platinum alloy of the present invention may further contain 0.001% by mass to 2% by mass of at least one first metal selected from the group consisting of iridium and ruthenium. Moreover, the combination of these components may be added so that a total amount may not exceed 2 mass% with respect to an alloy composition. Iridium and / or ruthenium can be added as a metal hardener to improve the hardness of the alloy, but over a wide range of concentrations, gradually improving the hardness without degrading the properties of the alloy. Therefore, iridium is preferable.

  The platinum alloy of the present invention may further contain 0.001% by mass to 2% by mass of at least one second metal selected from the group consisting of indium and gallium. Moreover, the combination of these components may be added so that a total amount may not exceed 2 mass% with respect to an alloy composition. Indium and gallium can be added to improve the precipitation hardening of the alloy. The platinum alloy of the present invention may further contain palladium in an amount of 0.001% to 5% by mass, preferably 0.25% to 2.5% by mass. The addition of palladium is useful for changing the color of the alloy.

  The platinum alloy of the present invention may further contain silicon in an amount of 0.001% to 0.5% by mass, preferably 0.1% to 0.3% by mass. It has been found that the addition of silicon in specific amounts improves the casting properties of the alloy and, as a result, smooths the cast product. Such an effect is particularly preferred when the alloy of the present invention is used for the manufacture of decorative articles that require good casting properties. It has been found that a certain amount of silicon dissolves in the Pt—Co—Cu alloy of the present invention and obtains the above-mentioned effects. In contrast, the addition of silicon to a high platinum content alloy is undesirable because it generally results in a non-uniform low liquid phase.

  The platinum alloy of the present invention may further contain zirconium in an amount of 0.001% to 0.5% by mass, preferably 0.1% to 0.3% by mass. It has been found that adding a specific amount of zirconium improves the workability of the alloy.

  According to a preferred embodiment of the present invention, in addition to Pt, Cu and Co, the total amount of other components contained in the platinum alloy does not exceed about 10% by weight, preferably based on the total weight of the platinum alloy, About 7.5% by weight, more preferably about 5% by weight, and most preferably about 4% by weight.

  The platinum alloy of the present invention may exist in a crystalline state or an amorphous state. The platinum alloy of the present invention is preferably present in a substantially crystalline state. The term “substantially crystalline state” as used herein means that the platinum alloy is more than 50% crystalline by volume. The platinum alloy is preferably at least about 90% crystalline by volume, more preferably at least 95%, and most preferably about 100% crystalline.

  While it is possible to use phosphorus as an additive to the platinum alloy to make the alloy more brittle and / or amorphous, it is not particularly preferred to add phosphorus to the alloy of the present invention. This is because amorphous alloys are not preferred. Therefore, when phosphorus is added to the alloy of the present invention, such addition needs to be in an appropriate amount. The amount of phosphorus contained in the platinum alloy of the present invention is less than 4.2% by mass, more preferably less than 3.4% by mass, and still more preferably 2.3% by mass with respect to the entire alloy composition. %, And most preferably about 1.5% by weight. According to another preferred embodiment, the platinum alloy of the present invention comprises less than about 2.0 wt.%, More preferably less than about 1 wt.% Phosphorus, based on the total alloy composition.

  The alloy may include any of a number of property enhancing agents, such as deoxidizers, grain reducing agents, viscosity reducing agents, or color change agents. The number and amount for other additives can vary based on the desired mechanical properties of the alloy and can be readily determined by one of ordinary skill in the art through routine experimentation.

  According to another embodiment of the invention, the platinum alloy is composed mainly of the following components, apart from impurities: 63.5% to 67.5% platinum, 1.5% to 8% by weight. % Cobalt and 24.5% to 35% copper by weight, and copper may be replaced by one or more of the following components: 0.001% to 2% by weight of at least 1 Specified first metal, 0.001% to 2% by weight of at least one second metal, 0.001% to 5% palladium, 0.001% to 0.001%. 5% silicon and / or 0.001% to 0.5% zirconium.

The alloys of the present invention exhibit good mechanical and physical properties such as tensile strength, Vickers hardness and elongation at break. The tensile strength of the platinum alloy of the present invention is in the range of 450 to 800 N / mm ² . The Vickers hardness of the platinum alloy of the present invention is measured in the softened state and is in the range of 130 to 210 HV10. The elongation at break of the platinum alloy of the present invention is at least about 20%.

  Another advantage of the present invention is that the color of the platinum alloy substantially corresponds to the color of platinum white, which is aesthetically very interesting PtCu950.

  The alloys of the present invention may be prepared by common alloying methods known in the art. The manufacture of alloys generally involves melting platinum, cobalt and copper and other components in specified amounts.

  Such a method may further comprise the step of hardening the alloy by cold working or heat treatment. The method may include an annealing step and a subsequent step of quenching the alloy before hardening the alloy.

  The alloy is usually cast from the melt and shaped under shielding gas. After forming, the alloy may optionally be heat treated under shielding gas to improve the mechanical properties of the alloy.

  In order to produce the platinum alloy composition of the present invention, a high temperature melting method is performed. For this, an induction melting apparatus as known in the art can be used. Always use extreme caution to limit metal contamination. This is because platinum is easily contaminated by many components that are generally present in the surroundings. Such precautions include, for example, melting a metal in a vacuum or an inert gas atmosphere, or suppressing contact with other metals and suppressing mixing with a silicon-based substance. It is done.

  The platinum alloy is preferably melted and blended simultaneously by induction heating in a crucible suitable for the platinum alloy. After melting, the alloy can be poured into water to form a grain-shot, then dried, weighed, and used for casting.

  When producing the alloys of the present invention, the components of the composition of the present invention can be either silica crucibles in induction furnaces (for small and rapid melts) or zirconium oxide crucibles (for large and slow melts). And are preferably melted. In the melting process, it is preferred to use a vacuum or an inert gas and at the same time set all the components of the alloy composition in the crucible. In melting the alloy, preferably the molten metal needs to be “turned” (utilizing a medium to low frequency induction field) to obtain a proper mixing of the metals.

  After the melting step, the resulting alloy nugget can be cold rolled and / or annealed to improve the mechanical quality of the mixture. Thereafter, the mixed metal composition can be re-melted by the above-described method, if necessary, to produce a shot or a plate.

  The production of the platinum alloy of the present invention may further include an annealing process. The annealing process may be performed in a furnace or using a torch, as is known in the art. The annealing temperature depends on the platinum content and melting point of the alloy and is readily determined by one skilled in the art through routine experimentation. The annealing process is preferably performed in a furnace in an atmosphere controlled by a shielding gas.

  The shielding gas can be any non-oxidizing inert gas such as argon, nitrogen or mixtures thereof; an antioxidant gas such as hydrogen, carbon monoxide, or “forming” or “decomposed ammonia” gas (nitrogen containing several percent hydrogen). It may be. It is also possible to protect the piece from oxidation by wrapping the alloy with a commercially available heat treated wrap.

  The alloys can be used in a wide range of gem parts, such as rings, fasteners, spring parts, even compression-spring setting of gemstones.

  Further, the alloy can be repeatedly annealed and heat treated / age hardened as required.

  As used herein, the term “age hardening” is substantially synonymous with the term “precipitation hardening” resulting from the formation of fine particles in a new component (phase) within a solid solution. The presence of these particles creates stress in the alloy and increases its yield strength and hardness. B. A. Rogers, “The Nature of Metals”, p. 320 (Iowa State University Press, 1964); W. See Pock, “Materials Science and Metallurgy”, page 266 (Reston Pub. Inc. 1981) and “The Metals Handbook”, page 1-2 (Am. Soc'y Metals, 1986).

  In the annealed / softened state of the alloy, the alloy can be processed by standard jewelry making techniques: extending, drawing, soldering, shaping, bending, punching the alloy It is possible. Such alloys can be used for various purposes, such as springs, gemstone installations in rings, pendants, bracelets, necklaces, precious metal arts.

  It should be noted that the smallest cross-sectional area and shape of the part is taken into account in the design of the jewelry or artistic structure. It is possible to adapt the alloy design to most forms. The basic form of such a design can be changed from a simple sheet to an annular and more complex spiral, V-shape. The object may be a wire, a sheet, all kinds of springs, pendants, chain links, brooches and the like. Standard gem soldering techniques can be used and repairs requiring heat can be performed. The alloy can be shaped, bent, constructed, annealed, and when the piece is made, the spring force and hardness can be restored by heat treatment.

  The ornament can be made by casting. Further, the hardness of the alloy may be further increased by heat treatment. The heat treatment may be performed in a range of 300 ° C to 950 ° C, and a preferable temperature range is a range of 600 ° C to 950 ° C, and generally about 800 ° C.

  A standard annealing process can generally soften the alloy at about 1000 ° C. to 1030 ° C. or higher.

  Alloys may be used in the form of wires, sheets or other products, and can also be given complex shapes and forms due to the combination of the alloy's significant hardness and significant ductility. is there. The alloys of the present invention can be used, for example, in the production of wedding rings. Such wedding rings are typically manufactured by grinding a tube into a blank and then further processing the blank by suitable methods such as grinding, drawing, forging, and polishing.

  Other jewelry that can be made from the alloys of the present invention include, for example, rings, necklaces, bracelets, earrings, bangles, decorative pins, watch bands, watch bodies, watches, toothpicks, and other ornaments such as ballpoint pens, paper Examples include knives and pocket knives.

  The following examples illustrate certain aspects of the invention, but such examples are not intended to limit the scope of the invention as defined in the claims.

  EXAMPLE An alloy having a composition as specified in the table below was weighed and melted under vacuum conditions in a zirconia crucible in a vacuum induction furnace at 1480-1500 ° C. to obtain a uniform melt. The alloy was cast in a steel mold to form a mass having dimensions of 20 × 140 mm.

  In the table below, the physical properties of the alloy specimens were defined. The melting range was determined by measuring the alloy cooling curve using a Degussa resistance furnace HR1 / Pt / PtRH10 equipped with a Linseis thermal element and a temperature-time plotter L250. The Vickers hardness was measured in accordance with German Industrial Standard 50133 using a Wolpert V-Testor 4251 instrument. Tensile strength, elongation at break and yield strength were measured in accordance with German Industrial Standard 50145 using a Zwick instrument from Zwick. The color was measured visually.

  Comparative Example A commercially available Pt / Cu 950/50 alloy was weighed and melted under vacuum conditions in a zirconia crucible in a vacuum induction furnace to obtain a uniform melt. The alloy was cast in a steel mold to form a mass having dimensions of 20 × 140 mm.

  The physical properties of the molded alloy specimens were tested as described above and specified in the table below.

  Experimental results have shown that the alloys of the present invention have superior casting, wear and wear properties compared to conventional Pt / Cu 950/50 alloys. Furthermore, the results of Example 1 showed that the castability of the alloy of the present invention was enhanced by adding a small amount of silicon. In addition, experimental results have shown that the molding properties and color tone of the alloys of the present invention are comparable to those of conventional Pt / Cu 950/50 alloys. The alloys of the present invention have been found to be good materials for the manufacture of jewelry such as rings, bracelets or necklaces.

  The principles of the present invention and the best mode expected when applying such principles have been described. It should be understood that the above description is illustrative only and that other meanings and techniques may be used without departing from the scope of the invention as defined in the claims.

Claims (29)

  The platinum content is 63.01 mass% to 69.99 mass%, the cobalt content is 1.5 mass% to 10 mass%, and the copper content is 20.01 mass% to 35.49. Platinum alloy that is mass%.   The platinum alloy according to claim 1, which is substantially in a crystalline state.   The platinum alloy according to claim 1, wherein the platinum content is 63.5 mass% to 66.5 mass%.   The platinum alloy according to claim 1, wherein the platinum content is 64 mass% to 66 mass%.   The platinum alloy according to claim 1, wherein the platinum content is approximately 65% by mass.   The platinum alloy according to any one of claims 1 to 5, wherein the cobalt content is 2.0 mass% to 6.0 mass%.   The platinum alloy according to any one of claims 1 to 6, wherein the cobalt content is 2.5 mass% to 5.5 mass%.   8. The method according to claim 1, further comprising at least one first metal selected from the group consisting of iridium and ruthenium, wherein the content of the first metal is 0.001% by mass to 2% by mass. Platinum alloy.   9. The method according to claim 1, further comprising at least one second metal selected from the group consisting of indium and gallium, wherein the content of the second metal is 0.001% by mass to 2% by mass. Platinum alloy.   The platinum alloy according to any one of claims 1 to 9, further comprising 0.001 to 5% by mass of palladium.   The platinum alloy according to any one of claims 1 to 10, further comprising 0.001 to 0.5 mass% of silicon.   The platinum alloy according to claim 11, wherein the silicon content is 0.1 mass% to 0.3 mass%.   The platinum alloy according to any one of claims 1 to 12, further comprising 0.001 to 0.5 mass% of zirconium.   The platinum alloy according to claim 13, wherein the zirconium content is 0.1 mass% to 0.3 mass%.   The platinum alloy according to any one of claims 1 to 14, wherein a total content of components other than platinum, copper, and cobalt is 10 mass% or less of the entire platinum alloy.   The platinum alloy according to any one of claims 1 to 15, wherein the total content of components other than platinum, copper, and cobalt is 7.5 mass% or less of the entire platinum alloy.   The platinum alloy according to any one of claims 1 to 16, wherein the total content of components other than platinum, copper, and cobalt is 2.0 mass% or less of the entire platinum alloy.   The platinum content is 63.5 mass% to 67.5 mass%, the cobalt content is 1.5 mass% to 8 mass%, and the copper content is 24.5 mass%. 35% by weight and copper is replaced by one or more of the following components: 0.001% to 2% by weight of at least one first metal as described above, 0.001% to 2% by weight At least one second metal described above, 0.001% to 5% palladium, 0.001% to 0.5% silicon, and / or 0.001% to 0.5%. The platinum alloy according to any one of claims 1 to 17, which is zirconium in mass%.   The platinum alloy according to any one of claims 1 to 18, wherein the tensile strength is 450 N / mm2 to 800 N / mm2.   The platinum alloy according to any one of claims 1 to 19, wherein the Vickers hardness is 130HV10 to 210HV10.   The platinum alloy according to any one of claims 1 to 20, which has an elongation at break of 20% or less.   The platinum alloy according to any one of claims 1 to 21, wherein the color tone substantially corresponds to a platinum white color tone of PtCu950.   The method for producing a platinum alloy according to any one of claims 1 to 22, comprising: (a) a step of mixing raw materials of the alloy; and (b) a step of melting the alloy.   A platinum-colored decorative material comprising the platinum alloy according to any one of claims 1 to 22.   A decorative article comprising the platinum alloy according to any one of claims 1 to 22.   26. The ornament according to claim 25, wherein the ornament is a ring, a necklace, an earring, a watch band, a watch body, a wristwatch, and other ornaments.   27. The method for manufacturing a decorative article according to claim 25 or 26, wherein the decorative article is molded from the platinum alloy according to any one of claims 1 to 22.   The decorative article according to claim 27, which is formed by casting.   A method of using the platinum alloy according to any one of claims 1 to 22 for manufacturing a ring, a necklace, an earring, a watch band, a watch body, and other jewelry.