EP3135781A1 - Precious metal jewelry alloy - Google Patents

Abstract

The invention relates to the use of a precious metal jewelery alloy for the production of watches, jewelery, jewelery articles and / or writing implements, this jewelery alloy containing rhodium and platinum. According to the invention, it is provided that the jewelery alloy used comprises rhodium in a proportion by weight of 40% by weight to 70% by weight and platinum in a proportion by weight of 60% by weight to 30% by weight, that the jewelery alloy used optionally comprises ruthenium, Iridium and / or gold in a proportion by weight of more than 0 wt .-% to 20 wt .-% together, and that the jewelery alloy further preferably palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-% in which case platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the abovementioned secondary alloy components, apart from conventional impurities, supplement to 100 wt .-%.

Description

The invention relates to a use of a precious metal jewelry alloy containing rhodium and platinum, for the production of jewelry such as watches, jewelry, jewelery and / or writing instruments, a method for producing a piece of jewelry from a tarnish precious metal jewelry alloy, and such a precious metal jewelry alloy.

In the jewelery and watch industry, a particularly white metal color of a jewelery alloy is desired, since in this way the gloss of white gemstones, in particular of diamonds, is supported in a particularly good manner.

In white gold jewelry alloys, their white color is often realized by an additional galvanic rhodium plating, since rhodium is the precious metal with the best white color. The disadvantage of a galvanic rhodium plating lies in their limited life, since the usually 0.2 micron thick rhodium layer is worn by the use of the jewelry piece. The white gold base material of the piece of jewelry is thereby visible and affects the appearance of the piece of jewelry, since the gloss and the color of white gold is worse than that of rhodium.

Previously known jewelry alloys have not reached the color and gloss of rhodium and were in particular not sufficiently tarnish-resistant. Pure rhodium is only of limited use for the production of jewelery such as jewelery, watches, jewelery or high-quality writing utensils because it is difficult to melt and pour, and rhodium can only be shaped well when hot. In addition, his powder metallurgical processing is very expensive and does not meet the high standards of gloss and polishability.

From the DE 10 2008 050 135 A1 discloses a method for the electrolytic deposition of an alloy of platinum and rhodium on in particular decorative articles, wherein the rhodium content in the alloy is at least 40 wt .-% to at most 85 wt .-%. The electrolysis is carried out at a pH of less than or equal to 1 and a current density greater than or equal to 2 A / dm ² in an aqueous solution as an electrolytic bath containing from 0.4 to 5.0 g / L platinum ions, 1.0 to 5 , 0 g / L rhodium ions and optionally one or more additives selected from the group consisting of conducting salts, brighteners, surfactants, wetting agents, noble metal complexing ligands or stabilizers.

With the described method, only the production of a galvanic coating, but not the formation of a piece of jewelry is possible. The color This alloy is comparable to the information given in the aforementioned document with silver, so it is not ideal white.

The DE 11 81 922 B discloses the use of a homogeneous platinum-rhodium alloy for spinnerets consisting of 25 to 40% rhodium and the remainder platinum.

The US 2003/0116528 A1 describes a platinum-rhodium alloy for electromechanical components containing 60 to 99.9% platinum and 0.1 to 40% rhodium.

The GB 1 178 349 A discloses platinum-rhodium alloys for wires in thermocouples containing 39 to 41 weight percent rhodium and the remainder platinum.

The JP 60-264330 A describes platinum-rhodium alloys for coating applications containing 60 to 99% platinum and 1 to 40% rhodium. All of the alloys described above are not intended for the jewelry industry and are not capable of achieving the desired ideal white color and resistance to tarnish.

From the Merker, J. et al: High Temperature Mechanical Properties of the Platinum Group Metals. In: Platinum Metals Rev., 45, 2001, (2), 74-82 discloses the binary phase diagram of rhodium and platinum.

It is therefore an object of the present invention to provide a massive precious metal jewelry alloy, which is suitable for use in the manufacture of jewelry such as jewelry, watches, jewelry and / or writing instruments, in particular the color and gloss of electrodeposited rhodium, or itself at least this white color and the gloss approximates and is resistant to tarnish. Another object of the invention is that a manufactured using such an alloy Jewel should be created. Likewise, a method for producing such a piece of jewelry is to be specified.

To solve this problem, the invention proposes that the jewelry alloy rhodium used for the production of the jewelry in a weight proportion of 40 wt .-% to 70 wt .-% and platinum in a weight proportion of 60 wt .-% to 30 wt .-% that the used jewelery alloy optionally comprises ruthenium, iridium and / or gold in a weight proportion of more than 0 wt .-% to 20 wt .-% together, and that the jewelery alloy more preferably palladium in a weight fraction of more than 0 wt. -% up to 30 wt .-%, wherein then platinum is replaced by palladium, with the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%.

The piece of jewelry according to the invention, such as a piece of jewelery, a watch, a watch case, jewelery, a writing instrument or a component thereof, is characterized in that the piece of jewelery is made of an alloy containing rhodium in a proportion by weight of 40% by weight to 70% by weight. % and platinum in a proportion by weight of 60% by weight to 30% by weight, the alloy optionally comprising ruthenium, iridium and / or gold in a proportion by weight of more than 0% by weight to a total of 20% by weight and which further preferably comprises palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, in which case platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, with usual impurities apart, to 100 wt .-% complete.

The inventive method for producing a piece of jewelry suggests that the piece of jewelry is made of a precious metal jewelry alloy, which rhodium in a weight fraction of 40 wt .-% to 70 wt .-% and Platinum in a proportion by weight of 60 wt .-% to 30 wt .-%, wherein the alloy optionally ruthenium, iridium and / or gold in a weight fraction of more than 0 wt .-% to 20 wt .-% together, and more preferably palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities to 100 wt .-% complete.

According to the invention, the precious metal jewelery alloy according to the invention provides that the jewelery alloy has rhodium in a proportion by weight of 40% by weight to 70% by weight and platinum in a proportion by weight of 60% by weight to 30% by weight Jewelery alloy optionally ruthenium, iridium and / or gold in a weight proportion of more than 0 wt .-% to 20 wt .-% together, and that the jewelery alloy further preferably palladium in a weight proportion of more than 0 wt .-% up to 30 % By weight, in which case platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the abovementioned secondary alloy components, apart from common impurities, add up to 100% by weight.

The alloy according to the invention or the invention is characterized in that it has tarnish resistance and an ideal white color. It has a hardness hard in the range of 350 to 370 HV and a soft hardness in the range of 160 to 170 HV and thus meets the requirements of the watch and jewelry industry in terms of sufficient wear resistance and the durability of filigree constructions. The jewelery alloy used according to the invention has the advantage that it is not brittle and therefore easily deformable, in particular by hot forming. Another advantage of the alloy used according to the invention is that it is particularly well suited for jewelry casting by the lost wax process.

The invention thus further provides that the precious metal jewelery alloy used according to the invention comprises ruthenium, iridium and / or gold up to a fraction of more than 0% by weight up to 20% by weight, preferably more than 0% by weight. to 10 wt .-%, wherein platinum replaced by ruthenium, iridium and / or gold and the proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities and admixtures, add up to 100 wt .-%. Such a measure has the advantage that the strength of the alloy used is further improved without affecting the color and gloss or the noble character of the alloy.

An advantageous development of the invention provides that the precious metal jewelery alloy used palladium in a weight fraction of up to 30%, preferably between 21 wt .-% and 29 wt .-% palladium, more preferably between 7 wt .-% and 12 wt % Palladium, with platinum being replaced by palladium. Such a measure has the advantage that in this way the expensive platinum can be replaced by the cheaper palladium without significantly impairing the high-quality properties of the precious metal jewelery alloy according to the invention.

A further advantageous embodiment of the invention provides that the precious metal jewelry alloy 45 to 70 wt .-% rhodium and 55 to 30 wt .-% platinum.

A further advantageous embodiment of the invention provides that the precious metal jewelry alloy 45 wt .-% to 65 wt .-% rhodium and 55 wt .-% to 35 wt .-% platinum.

A further advantageous embodiment of the invention provides that the precious metal jewelry alloy according to the invention 45 wt .-% to 65 wt .-%, preferably 48 wt .-% to 52 wt .-% rhodium and 55 wt .-% to 45 wt .-%, preferably 52 wt .-% to 48 wt .-% platinum.

A further advantageous embodiment of the invention provides that the precious metal jewelery alloy according to the invention 47 to 53, preferably 48 to 52 wt .-% rhodium and 53 to 47 wt .-%, preferably 52 to 48 wt .-% platinum.

A further advantageous embodiment of the invention provides that the jewelery alloy according to the invention comprises about 50% by weight of rhodium and about 50% by weight of platinum.

Hereinafter, the precious metal jewelery alloy will be explained with reference to an exemplary embodiment in which 40 to 70 wt%, preferably 50 wt% rhodium and 60 to 30 wt% platinum, preferably 50 wt% platinum, are used. The latter alloy has an atomic ratio Rh / Pt of 65:35, so that two-thirds of the atoms of the alloy are rhodium atoms. The proportion of rhodium and / or platinum thus replenishes substantially to 100 wt .-%, apart from conventional admixtures and impurities.

Preferably, in this case, the precious metal jewelry alloy 45 wt .-% to 70 wt .-% rhodium and 55 wt .-% to 30 wt .-% of platinum, again, it is preferred that the content of rhodium preferably 45 to 65 wt. -%, more preferably 47 to 53 wt .-% and especially preferably 48 wt .-% to 52 wt .-% is, and that the content of platinum accordingly 55 to 30 wt .-%, preferably 55 to 35 parts by weight. %, more preferably 53 to 47 wt .-% and in particular 52 wt .-% to 48 wt .-% is.

Surprisingly, it appears that the above alloy with about 50% by weight rhodium and about 50% by weight platinum is sufficient to produce the ideal white To achieve color and gloss of electrodeposited rhodium or at least approximately to achieve this white color and shine.

Surprisingly, it has been found that the described alloy is very well suited for investment casting by the lost wax process, whereby conventional equipment and investments can be used for the casting of platinum alloys. The castings produced from the described alloy have little to no porosity, the hardness is 160 to 170 HV, and surface defects due to reactions with investment material were practically not observed. The unexpectedly low solidification shrinkage of the described alloy compared to other jewelry materials such as platinum 950 or white gold 750 prevents shrinkage porosity, which is a major problem in jewelery casting. Another advantage is that gas and embedding mass reactions are almost impossible since both rhodium and platinum have high chemical resistance. This also implies that a re-pouring of remnants of the precious metal jewelery alloy described is feasible without much difficulty, since the described precious metal Schmucklegier-ung is not affected by chemical reactions. The possible reuse of remnants of the casting process therefore leads to optimal material utilization. A further advantage of the described alloy in connection with jewelery casting is that castings produced by jewelery have dimensions close to the final dimensions, which, in conjunction with good re-pourability, results in an economical use of material.

A wire made from the described alloy has a hardness in the range of 160 to 170 HV in the soft state and from 350 to 370 HV in the hard state. From the described alloy it is therefore possible to produce simple semi-finished products, wherein good deformability can be achieved by hot forming.

The precious metal jewelery alloy described are still ruthenium, iridium and / or gold as secondary alloy components in a weight proportion of more than 0 wt .-% up to 20 wt .-%, preferably more than 0 wt .-% up to 10 wt. %, with platinum being replaced by ruthenium, iridium and / or gold, so that the proportions of rhodium and platinum and the abovementioned components, apart from customary admixtures and impurities, add up to 100% by weight.

Furthermore, it can be provided that up to 50% of the platinum, preferably up to 20% of the platinum, is replaced by palladium, so that the described precious metal jewelry alloy then up to 30 wt .-% palladium, preferably between 21 wt. % and 29% by weight of palladium, and more preferably between 7% by weight and 12% by weight of palladium, wherein then by weight of rhodium, platinum and palladium, apart from conventional admixtures and impurities, too 100 wt .-% complete. This measure has a positive influence on the material price of the alloy, since palladium is much cheaper than platinum.

In summary, it should be noted that the described precious metal jewelry alloy in a particularly advantageous manner for the production of ideal white, tarnish jewelery, such as jewelry of all kinds, jewelery, watches, watch cases and writing instruments, to name a few of the preferred applications enumerate, is suitable.

Claims (15)

Use of a precious metal jewelery alloy for the production of watches, jewelery, jewelery articles and / or writing instruments, this jewelery alloy containing rhodium and platinum, characterized in that the jewelery alloy rhodium is used in a proportion by weight of 40 wt .-% to 70 wt .-% and Platinum in a proportion by weight of 60% by weight to 30% by weight, that the jewelry alloy used optionally has ruthenium, iridium and / or gold in a proportion by weight of more than 0% by weight to 20% by weight in total, and that the jewelery alloy further preferably has palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, in which case platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components of usual impurities apart, to 100 wt .-% complete. Use of the precious metal jewelery alloy according to claim 1, characterized in that the jewelery alloy used comprises rhodium in a proportion by weight of 45 wt .-% to 70 wt .-% and platinum in a weight proportion of 55 wt .-% to 30 wt .-% and in that the jewelery alloy used optionally comprises ruthenium, iridium and / or gold in a proportion by weight of more than 0 wt .-% to 20 wt .-%, and in that the jewelery alloy more preferably palladium in a weight fraction of more than 0 wt. -% up to 30 wt .-%, wherein then platinum is replaced by palladium, with the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%. Use of the precious metal jewelery alloy according to one of the preceding claims, characterized in that the jewelery alloy rhodium used in a weight fraction of 45 wt .-% to 65 wt .-% and platinum a weight fraction of 55 wt .-% to 35 wt .-% and in that the jewelery alloy used optionally comprises ruthenium, iridium and / or gold in a proportion by weight of more than 0 wt .-% to 20 wt .-%, and in that the jewelery alloy more preferably palladium in a weight fraction of more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%. Use of the precious metal jewelery alloy according to one of the preceding claims, characterized in that the jewelery alloy used rhodium in a weight fraction of 47 to 53 wt .-%, preferably in a weight fraction of 48 wt .-% to 52 wt .-%, and platinum in a weight proportion of 53 to 47 wt .-%, preferably in a weight proportion of 52 wt .-% to 48 wt .-%, and that the used jewelery alloy optionally ruthenium, iridium and / or gold in a weight proportion of more than 0 Wt .-% to 20 wt .-% together, and that the jewelery alloy further preferably palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the aforementioned secondary alloy components, apart from usual impurities, to 100 wt .-% complete. Use of the precious metal jewelery alloy according to one of the preceding claims, characterized in that the jewelery alloy used is about 50% by weight rhodium and about 50% by weight Platinum, and in that the jewelery alloy used optionally comprises ruthenium, iridium and / or gold in a proportion by weight of more than 0 wt .-% to 20 wt .-%, and in that the jewelery alloy further preferably palladium in a weight fraction of more than 0 Wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, with the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%. Jewelery such as jewelry, watch, watch cases, jewelery, writing instrument, characterized in that the piece of jewelery is made of an alloy containing rhodium in a weight proportion of 40 wt .-% to 70 wt .-% and platinum in a weight proportion of 60 wt. % to 30% by weight, that the alloy optionally comprises ruthenium, iridium and / or gold in a proportion by weight of more than 0 wt .-% to 20 wt .-% together, and which further preferably palladium in a weight fraction of more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the aforementioned secondary alloy components, with the exception of conventional impurities, add up to 100 wt .-% , Piece of jewelery according to claim 6, characterized in that the alloy is a precious metal jewelery alloy according to one of claims 11 to 15. A method for producing a piece of jewelry, such as jewelry, a clock, a watch case, a jewelery or a writing instrument, characterized in that the piece of jewelry is made of a precious metal jewelry alloy, which rhodium in a weight fraction of 40 wt .-% to 70 wt. -% and platinum in a weight percentage of 60 Wt .-% to 30 wt .-%, wherein the alloy optionally ruthenium, iridium and / or gold in a weight fraction of more than 0 wt .-% to 20 wt .-% together, and more preferably palladium in a weight fraction from more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities to 100 wt .-% complement , A method according to claim 8, characterized in that the piece of jewelry is produced using a lost wax process. A method according to claim 8, characterized in that a precious metal jewelery alloy according to any one of claims 11 to 15 is used. Precious metal jewelery alloy, this jewelery alloy containing rhodium and platinum, characterized in that the jewelery alloy rhodium in a weight proportion of 40 wt .-% to 70 wt .-% and platinum in a weight proportion of 60 wt .-% to 30 wt .- % that the used jewelery alloy optionally ruthenium, iridium and / or gold in a weight proportion of more than 0 wt .-% up to 20 wt .-%, and that the jewelery alloy more preferably palladium in a weight fraction of more than 0 wt .-% up to 30 wt .-%, wherein then platinum is replaced by palladium, wherein the proportions by weight of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%. Noble metal jewelery alloy according to claim 11, characterized in that the jewelery alloy rhodium in a weight proportion of 45 wt .-% to 70 wt .-% and platinum in a weight fraction of 55 wt .-% to 30 wt .-%, and that the jewelery alloy optionally ruthenium, iridium and / or gold in a weight proportion of more than 0 wt .-% together 20 wt .-%, and that the jewelery alloy further preferably comprises palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, in which case platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, except for ordinary impurities, add up to 100% by weight. Noble metal jewelery alloy according to one of the preceding claims, characterized in that the jewelery alloy rhodium in a weight proportion of 45 wt .-% to 65 wt .-% and platinum has a weight fraction of 55 wt .-% to 35 wt .-%, and that the jewelery alloy optionally comprises ruthenium, iridium and / or gold in a weight proportion of more than 0 wt .-% to 20 wt .-% together, and that the jewelery alloy more preferably palladium in a weight fraction of more than 0 wt .-% to to 30 wt .-%, in which case platinum is replaced by palladium, wherein the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-% complement. Noble metal jewelery alloy according to one of the preceding claims, characterized in that the jewelery alloy rhodium in a weight fraction of 47 to 53 wt .-%, preferably in a weight fraction of 48 wt .-% to 52 wt .-%, and platinum in a weight fraction from 53 to 47 wt .-%, preferably in a weight fraction of 52 wt .-% to 48 wt .-%, and that the jewelery alloy optionally ruthenium, iridium and / or gold in a weight fraction of more than 0 wt .-% to 20 wt .-% together, and that the jewelery alloy further preferably palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, in which case platinum is replaced by palladium, with the weight proportions of rhodium, platinum and the aforementioned secondary alloy components, apart from conventional impurities, to 100 wt .-%. The precious metal jewelery alloy according to any one of the preceding claims, characterized in that the jewelery alloy comprises about 50% by weight of rhodium and about 50% by weight of platinum, and that the jewelery alloy optionally comprises ruthenium, iridium and / or gold in a weight fraction of more than 0 to 20 wt .-%, and that the jewelery alloy further preferably comprises palladium in a weight proportion of more than 0 wt .-% up to 30 wt .-%, in which case platinum is replaced by palladium, wherein Apart from the usual impurities, the proportions by weight of rhodium, platinum and the abovementioned secondary alloying components add up to 100% by weight.