KR20120008073A - Palladium-jewelry alloy - Google Patents

Abstract

Palladium jewelery alloy
The palladium jewelery alloy of the present invention comprises 0.1% to 15.0 of at least one element selected from the group consisting of 58.0% to 76.5% by weight of palladium, 0.5% to 41.5% by weight of silver and / or copper, gallium, germanium and indium. Wt%, and 0.1 wt% to 10.0 wt% zinc.
Preferably, 0.05% to 5.0% by weight of tungsten and / or cobalt may also be included.
Furthermore, the alloy may comprise 0.001% to 1.0% by weight of at least one element selected from the group comprising iridium, rhodium and ruthenium.
The alloy according to the invention is suitable for the production of semifinished products, in particular in the jewelry industry, and more particularly for the production of tubes and rings.

Description

Palladium jewelery alloy {PALLADIUM-JEWELRY ALLOY}

The present invention mainly relates to novel palladium jewelery alloys and semifinished products made from such alloys.

Palladium is an element of the so-called group of platinum metals. It is a bright white like platinum, but much lighter than platinum and fairly hard. This is also generally much cheaper than platinum.

In the manufacture of jewelry, palladium is often used for applications that are mainly added to other elements, especially to gold. For example, palladium is often used as an alloying additive in the "discoloration" of gold to form so-called white gold or gray gold.

Despite the advantageous properties, relatively few jewels are made of palladium or palladium alloys. This fact itself is surprising because palladium does not react with oxygen at room temperature and does not discolor easily and maintains metallic luster.

Notwithstanding this fundamentally advantageous feature of palladium for the jewelry sector, Applicants are currently aware that only palladium alloys with a pure content of 950 and 500 can be used, not pure palladium 999, for jewelry products.

Accordingly, the present invention aims to make more palladium alloys available for jewelry products. In particular, these alloys are intended to be suitable for the manufacture of tubes and rings for making wedding rings. For this purpose, it is generally oriented to achieve a hardness of at least 180 HV (Vickers hardness).

This problem is solved by a palladium jewelery alloy having the features of claim 1. Preferred embodiments of these alloys are described in the dependent claims 2 to 20. The invention also comprises a semifinished product according to claims 21 and 22.

All phrases of the claims are made by the contents of this specification.

According to the present invention, novel palladium jewelery alloys include:

Palladium (Pd) 58.0% to 76.5%,

-0.5 to 41.5 weight percent silver (Ag) and / or copper (Cu),

0.1% to 15.0% by weight of at least one element selected from the group consisting of gallium (Ga), germanium (Ge) and indium (In), and

0.1% to 10.0% zinc (Zn).

Here, the palladium content specifies the fine content of the claimed jewelry alloys. The addition of silver or copper affects the molding properties and the color tone of the alloy. The addition of gallium, germanium and / or indium affects the hardness and melting point of the alloy. The addition of zinc has a positive effect on the molding properties and hardness of the alloy.

Furthermore, the jewelery alloy according to the invention additionally comprises tungsten (W) and / or cobalt (Co) in a range of 0.05% to 5.0% by weight. The addition of these two elements mainly affects the hardness of the alloy and the fineness of the granulation.

In addition, it is more preferable that the jewelery alloy according to the present invention additionally contains 0.001% to 1.0% by weight of at least one element selected from the group containing iridium (Ir), rhodium (Rh) and ruthenium (Ru). . The addition of these elements likewise leads to finer crystallization of the alloy.

Regarding the silver content, a silver content between 10.0% and 32.0% by weight is preferred for all the above-mentioned jewelery alloys of the present invention. Within this range, the silver content on the one hand between 10.0% and 20.0% by weight or on the other hand between 23.0% and 32.0% by weight should be particularly emphasized.

In addition, with respect to the content of copper, a copper content of between 3.0% by weight and 15.0% by weight is preferred for all the above-mentioned jewelery alloys of the present invention. Within this range, the copper content on the one hand between 3.0% and 8.0% by weight or on the other hand between 8.0% and 15.0% by weight should be particularly emphasized.

As mentioned above, gallium, germanium and / or indium, which are elements contained in the jewelery alloy according to the invention, are known as so-called melt-lowerers, ie by adding these elements, these elements are included. Melting points can be lower when compared to alloys that do not. Moreover, these elements can increase the hardness of the alloy obtained.

In this context, the gallium, germanium and / or indium content of the jewelery alloy according to the invention is preferably 0.1% to 3.0% by weight, in particular 0.5% to 2.0% by weight. Within the range just mentioned, the content between 0.8% and 1.6% by weight should be particularly emphasized.

In the case of the present invention, in the above context, when at least gallium is included in the group of the elements mentioned (gallium, germanium and indium), it is more preferable that only gallium is preferably provided in the alloy as such an additive.

The zinc content of the jewelery alloy according to the invention is preferably 0.5% to 4.0% by weight, in particular 1.0% to 3.0% by weight. Within the range just mentioned, the zinc content between 1.2% and 2.5% by weight should be particularly emphasized.

In the case of the jewelery alloy according to the invention, the tungsten and / or cobalt content is preferably 0.1% to 2.0% by weight, in particular 0.1% to 1.0% by weight. Within the range just mentioned, tungsten and / or cobalt content between 0.2% and 0.6% by weight should be particularly emphasized.

Furthermore, in the case of the present invention, it is preferred if the element from the group comprising tungsten and cobalt is preferably tungsten.

As mentioned above, in the case of a preferred embodiment of the invention, at least one element is included in the group comprising iridium, rhodium and ruthenium. As also pointed out earlier, these elements are known as so-called grain refiners, which can ensure the acquisition of alloys with smaller grain sizes as compared to alloys in which these elements do not contain these elements. Because.

In this context, preference is given in the case of the present invention when the iridium, rhodium and / or ruthenium content is from 0.02% to 1.0% by weight, in particular from 0.02% to 0.2% by weight. Within the range just mentioned, the iridium, rhodium and / or ruthenium content between 0.02% and 0.08% by weight should be further emphasized.

According to the present invention, among the above-mentioned elements iridium, rhodium and ruthenium, when at least ruthenium is included, it is preferable that only ruthenium is provided as such an additive.

Furthermore, three subgroups of preferred embodiments of the palladium jewelery alloy according to the invention can be highlighted in the case of the invention. These embodiments are divided into 585 (i.e. 58.5 wt.%), 600 (i.e. 60.0 wt.%) And 750 (ie 75.0 wt.%), Depending on the pure palladium content, with particular emphasis on embodiments having a pure palladium content of 585.

Thus, the first group of preferred embodiments of jewelery alloys according to the invention consists of

58.0% to 59.0% by weight of palladium, preferably 58.5% by weight,

25.0% to 30.0% silver,

10.0% to 12.0% copper,

Gallium, germanium and / or indium, preferably 0.9% to 1.1% by weight gallium,

1.4 weight% to 1.6 weight% zinc,

Tungsten and / or cobalt, preferably 0.3% to 0.6% by weight tungsten, and

Iridium, rhodium and / or ruthenium, preferably from 0.04% to 0.06% by weight ruthenium.

In particular, such jewelry alloys consist of

58.5 weight percent of palladium,

-27.85 weight percent silver,

10.8% copper,

Gallium 1.0% by weight,

1.5 weight percent zinc,

0.3 weight percent tungsten and

Ruthenium 0.05% by weight.

Thus, the second group of preferred embodiments of the jewelery alloy according to the invention consists of

59.0% to 61.0% by weight of palladium, preferably 60.0% by weight,

25.0% to 30.0% silver,

8.0 wt% to 10.0 wt% copper,

Gallium, germanium and / or indium, preferably 0.9% to 1.1% by weight gallium,

1.8 weight% to 2.2 weight% zinc,

Tungsten and / or cobalt, preferably 0.3% to 0.6% by weight tungsten, and

Iridium, rhodium and / or ruthenium, preferably from 0.04% to 0.06% by weight ruthenium.

In particular, such jewelry alloys consist of

Palladium 60.0% by weight,

-27.75 weight percent silver,

8.7% copper,

Gallium 1.0% by weight,

2.0 weight percent zinc,

0.5 weight percent tungsten and

Ruthenium 0.05% by weight.

Thus, the third group of preferred embodiments of jewelery alloys according to the invention consists of

Palladium 74.0% to 76.0% by weight, preferably 75.0% by weight,

13.0 to 17.0 weight percent silver,

4.5 to 7.0 weight percent copper,

Gallium, germanium and / or indium, preferably 1.4% to 1.6% gallium,

1.8 weight% to 2.2 weight% zinc,

Tungsten and / or cobalt, preferably from 0.2% to 0.4% by weight of tungsten, and

Iridium, rhodium and / or ruthenium, preferably from 0.04% to 0.06% by weight ruthenium.

In particular, such jewelry alloys consist of

Palladium 75.0% by weight,

-15.25 weight percent silver,

5.9% by weight of copper,

Gallium 1.5% by weight,

2.0 weight percent zinc,

0.3 weight percent tungsten and

Ruthenium 0.05% by weight.

Furthermore, the jewelery alloy according to the invention preferably has a Vickers hardness which is so-called 180 HV or more (annealed), in particular 200 (± 10) HV.

Hardness tests according to Vickers are known to those skilled in the art. HV 5 thus corresponds to a test load of 50 N (newtons). In the case of precious metal alloys, the specification is a customary description of the hardness of such materials.

In addition, the jewelery alloy according to the present invention is preferably 12.0 g / cm ³ Or, in particular, a relative density of 11.5 g / cm ³ or less. In the case of these preferred alloys according to the invention, they are relatively lightweight and therefore inexpensive materials. For comparison, known 585 white-gold alloys containing palladium have, for example, a relative density of 14.3 g / cm ³ and known 750 white-gold alloys having palladium even have a relative of 15.9 g / cm ³ . Has a density.

Moreover, the palladium-jewelry alloy according to the present invention may have a melting section below 1250 ° C. Preferably, this melting section is between 1140 ° C and 1220 ° C.

It is to be noted that in this context alloys, in particular alloys used in the jewelry industry, do not have an exact melting point, but have a melting range, so-called melting section. Within this melting zone, the alloy first softens, gradually increases in fluidity and then passes into the actual liquid state. In the process of such alloys, it is thus advantageous if this melting section is as low as possible, thereby allowing them to be melted in a simple manner and further processed.

Finally, the invention comprises a semifinished product for the production of jewelry, at least in part, preferably all of which are made of the alloy according to the invention. It is known that these semi-finished products are prefabricated in geometric form from the corresponding alloying materials, which are then further processed by hand or industrial methods to form individual jewelery final products. In the field of jewelry, such semi-finished products are generally, for example, tubes, rods, rings, sheets, strips, wires and the like. They are first made into an unfinished casting and then further processed into a final semifinished product, generally having the desired dimensions, and preferably molded.

According to the invention, it is preferred if the semifinished product according to the invention is a tubular or annular semifinished product. Such semi-finished products are particularly well suited for the manufacture of jewelry rings, including wedding rings.

The present invention encompasses a series of several benefits in aggregate.

For example, the first advantage to be included with the use of palladium is in appearance. The palladium jewelery alloy according to the invention has high color stability and has a beautiful off-white color. Since the alloy is resistant to discoloration, no rhodium coating (rhodanizing) is required unless it is desired simply for aesthetic reasons. As is known, so-called rhodium plating is a chemical coating or electrocoating of a metal with rhodium. Such coatings are chemically and physically resistant and have a chrome-like gloss.

In addition, the alloy according to the invention has high ductility. That is, the material has high formability before fracture or rupture. Moreover, the alloy according to the invention has a micro-crystalline microstructure, for example having an average grain size of less than 50 μm, in particular in the range from 20 to 35 μm. Thus, they can work as hand tools and machine tools, for example by the very commonly used CNC (computerized numerical control) technology. This also applies to diamond tools including traditional cutting tips / inserts and PCDs (polycrystalline diamond).

In the case of the alloy according to the invention, a hardness of at least 180 HV (Vickers hardness, annealed, i.e. so-called soft hardness) can be easily achieved and therefore such alloys, especially also 585 (58.5% by weight) An alloy having a pure palladium content of is suitable for the production of wedding rings. In this context, wedding rings with different colors can also be produced using the jewelry alloy according to the invention, which also has alloys with different colors, in particular by the so-called diffusion welding. In this process, the metallic workpieces are connected to each other with very high quality welded connections. The process itself and the process parameters are well known to those skilled in the art. The alloy according to the invention is not only able to be machined by diffusion welding, but also continues to have a hardness of at least 180 HV thereafter (no deformation).

Moreover, it should be emphasized once again that the relative density of alloys of other metals of pure content comparable to the relative density of the alloys according to the invention, in particular less than 12.0 g / cm ³ , preferably less than 11.5 g / cm ^3. More noticeably lower. Moreover, due to the use of palladium as the (main) alloy element, the alloy according to the invention is considerably cheaper than an alloy having a comparable pure content of platinum, for example.

Therefore, the alloy according to the invention offers a low-cost alternative to white-gold alloys having a gold content of 585, for example, and it is also possible to use the alloy according to the invention in combination with such an alloy.

Finally, it should be emphasized that the alloy according to the invention can be produced by traditional strand casting processes. Strand casting is known to those skilled in the art as a process for producing semifinished products from metals and alloys, which processes are generally carried out continuously to provide a continuous strand of the desired semifinished product. As mentioned above, since the melting zones of the alloys according to the invention are generally located below 1250 ° C., they can be melted and processed further in a simple manner by such a process. Especially in the case of strand casting, very high melting intervals are never required to be able to use the process. In the case of strand casting, the molten material must have a sufficiently low viscosity over a certain time period in order to transform the material into strands. Early curing of the material should be prevented.

The features described and further features of the invention are apparent from the following examples which relate to the dependent claims. Individual features may be embodied in the embodiments themselves or in combination with each other.

Example

With a total weight of 1000 (‰), a palladium alloy according to the present invention having a pure palladium content of 585 is produced. The individual components are as follows:

Palladium (Pd) 585,

Silver 278.5,

Copper (108),

Gallium (Ga) 10,

Zinc (Zn) 15,

Tungsten (W) 3, and

Ruthenium (Ru) 0.5.

Converted by weight percent, the alloy according to the invention consequently has the following composition:

58.5 weight percent of palladium,

-27.85 weight percent silver,

10.8% copper,

Gallium 1.0% by weight,

1.5 weight percent zinc,

0.3 weight percent tungsten and

Ruthenium 0.05% by weight.

These components are melted in an induction furnace using suitable alloy powders.

The resulting alloy has a melting zone between 1145 ° C. and 1220 ° C. and thus can be processed into semi-finished products, in particular tubes and rings, in the strand casting process. The hardness of the annealed alloy (at 850 ° C.) is between 180 HV and 200 HV. The alloy has a relative density of 10.9 g / cm ³ . The alloy has fine-grains (average grain size of 50 μm or less) and can work well (including machines) (turning and milling operations) and can also be molded, diffused welded and polished.

Claims (22)

Palladium Jewelry Alloys Containing
Palladium 58.0% to 76.5%,
0.5% to 41.5% by weight of at least one element selected from silver and copper,
0.1% to 15.0% by weight of at least one element selected from the group comprising gallium, germanium and indium, and
0.1% to 10.0% zinc. The palladium jewelery alloy of claim 1, further comprising 0.05% to 5.0% by weight of at least one element selected from tungsten and cobalt. The palladium jewelery alloy of claim 1 or claim 2 comprising 0.001% to 1.0% by weight of at least one element selected from the group comprising iridium, rhodium and ruthenium. Palladium jewelery alloy according to claim 1, wherein the silver content is between 10.0% and 32.0% by weight, preferably between 10.0% and 20.0% by weight or between 23.0% and 32.0% by weight. . 3. Palladium jewelery alloy according to claim 1 or 2, characterized in that the copper content is between 3.0% and 15.0% by weight, preferably between 3.0% and 8.0% by weight or between 8.0% and 15.0% by weight. . The method according to claim 1 or 2, wherein the content of at least one selected from gallium, germanium and indium is from 0.1% to 3.0% by weight, preferably from 0.5% to 2.0% by weight, in particular from 0.8% to 1.6% by weight. Palladium jewelry alloy, characterized in that. The palladium jewelery alloy according to claim 1 or 2, wherein the element in the group containing gallium, germanium and indium is preferably gallium. The palladium jewelery alloy according to claim 1, wherein the zinc content is from 0.5% to 4.0% by weight, preferably from 1.0% to 3.0% by weight, in particular from 1.2% to 2.5% by weight. The palladium jewelery according to claim 2, wherein the content of at least one selected from tungsten and cobalt is from 0.1% to 2.0% by weight, preferably from 0.1% to 1.0% by weight, in particular from 0.2% to 0.6% by weight. alloy. The palladium jewelery alloy according to claim 2, wherein the element in the group comprising tungsten and cobalt is preferably tungsten. The method of claim 3, wherein the content of at least one selected from iridium, rhodium and ruthenium is from 0.02% to 1.0% by weight, preferably from 0.02% to 0.2% by weight, in particular from 0.02% to 0.08% by weight. Palladium jewelery alloy. The palladium jewelery alloy according to claim 3, wherein the element in the group comprising iridium, rhodium and ruthenium is preferably ruthenium. The palladium jewelery alloy according to claim 1 or 2, comprising:
58.0% to 59.0% by weight of palladium, preferably 58.5% by weight,
25.0% to 30.0% silver,
10.0% to 12.0% copper,
At least one element selected from gallium, germanium and indium, preferably from 0.9% to 1.1% by weight of gallium,
1.4 weight% to 1.6 weight% zinc,
At least one element selected from tungsten and cobalt, preferably from 0.3% to 0.6% by weight tungsten, and
At least one element selected from iridium, rhodium and ruthenium, preferably 0.04% to 0.06% by weight ruthenium. The palladium jewelery alloy according to claim 13, comprising:
58.5 weight percent of palladium,
-27.85 weight percent silver,
10.8% copper,
Gallium 1.0% by weight,
1.5 weight percent zinc,
0.3 weight percent tungsten and
Ruthenium 0.05% by weight. The palladium jewelery alloy according to claim 1 or 2, comprising:
59.0% to 61.0% by weight of palladium, preferably 60.0% by weight,
25.0% to 30.0% silver,
8.0 wt% to 10.0 wt% copper,
At least one element selected from gallium, germanium and indium, preferably from 0.9% to 1.1% by weight of gallium,
1.8 weight% to 2.2 weight% zinc,
At least one element selected from tungsten and cobalt, preferably from 0.3% to 0.6% by weight tungsten, and
At least one element selected from iridium, rhodium and ruthenium, preferably 0.04% to 0.06% by weight ruthenium. 16. The palladium jewelery alloy of claim 15 consisting of:
Palladium 60.0% by weight,
-27.75 weight percent silver,
8.7% copper,
Gallium 1.0% by weight,
2.0 weight percent zinc,
0.5 weight percent tungsten and
Ruthenium 0.05% by weight. The palladium jewelery alloy according to claim 1 or 2, comprising:
Palladium 74.0% to 76.0% by weight, preferably 75.0% by weight,
13.0 to 17.0 weight percent silver,
4.5 to 7.0 weight percent copper,
At least one element selected from gallium, germanium and indium, preferably from 1.4% to 1.6% by weight of gallium,
1.8 weight% to 2.2 weight% zinc,
At least one element selected from tungsten and cobalt, preferably from 0.2% to 0.4% by weight of tungsten, and
At least one element selected from iridium, rhodium and ruthenium, preferably 0.04% to 0.06% by weight ruthenium. 18. The palladium jewelery alloy of claim 17 comprising:
Palladium 75.0% by weight,
-15.25 weight percent silver,
5.9% by weight of copper,
Gallium 1.5% by weight,
2.0 weight percent zinc,
0.3 weight percent tungsten and
Ruthenium 0.05% by weight. The palladium jewelery alloy of claim 1, wherein the alloy has a hardness of at least 180 HV. The palladium jewelery alloy according to claim 1 or 2, characterized in that the alloy has a relative density of less than 12.0 g / cm ³ , preferably less than 11.5 g / cm ³ . Semi-finished product for the manufacture of jewelry, characterized in that it is made, at least in part, preferably all, of an alloy according to claim 1. A semifinished product according to claim 21 which is a tubular or annular semifinished product.