WO2010133555A1

WO2010133555A1 - Palladium jewelry alloy

Info

Publication number: WO2010133555A1
Application number: PCT/EP2010/056751
Authority: WO
Inventors: Heike Tews; Georg Steiner
Original assignee: Heimerle + Meule Gmbh
Priority date: 2009-05-18
Filing date: 2010-05-17
Publication date: 2010-11-25
Also published as: EP2432904A1; DE102009022357A1; KR20120008073A; JP2012527529A; EP2432904B1; DE202009013204U1

Abstract

The invention relates to a palladium jewelry alloy comprising 58.0 wt.% to 76.5 wt.% palladium, 0.5 wt.% to 41.5 wt.% silver and/or copper, 0.1 wt.% to 15.0 wt.% of at least one element selected from the group comprising gallium, germanium, and indium, and 0.1 wt.% to 10.0 wt.% zinc. Preferably, 0.05 wt.% to 5.0 wt.% tungsten and/or cobalt can also be contained. The alloy can further contain 0.001 wt.% to 1.0 wt.% of at least one element selected from the group comprising iridium, rhodium, and ruthenium. The alloy according to the invention is exceptionally suitable for the production of semi-finished products for the jewelry industry, in particular for the production of tubes and rings.

Description

description

Palladium jewelery alloy

The invention relates in the first place to new palladium jewelery alloys and semi-finished products produced with the aid of these alloys.

Palladium is an element from the group of so-called platinum metals. It is bright white like platinum, but much lighter than platinum and much harder. It is usually much cheaper than platinum.

In jewelery production, palladium has been used primarily as an additive to other elements, especially gold. Thus, palladium is often used as an alloying additive in the "decolorization" of gold to so-called white gold or gray gold.

Jewelry made of palladium or palladium alloys is comparatively rare despite its favorable properties. This is surprising since palladium does not react with oxygen at room temperature, is very tarnish-resistant and retains its metallic luster. Despite these fundamentally favorable properties of palladium for the jewelery sector, only palladium alloys with a fineness of 950 and 500 are currently available to the knowledge of the applicant for jewelery in addition to fine palladium (999).

Accordingly, the invention has the object to provide for jewelry other palladium alloys available. In particular, such alloys should be suitable for the production of pipes and rings for the production of wedding rings. For these purposes, a hardness of at least 180 HV (Vickers hardness) is usually sought.

This object is achieved by the palladium-jewelery alloys with the features of claim 1. Preferred embodiments of these alloys are described in the dependent claims 2 to 20. Furthermore, the invention comprises the semi-finished products according to claims 21 and 22.

The wording of all claims is hereby incorporated by reference.

According to the invention, the new palladium jewelery alloy comprises 58.0% by weight to 76.5% by weight of palladium (Pd), 0.5% by weight to 41.5% by weight of silver (Ag) and / or copper (Cu), 0.1 wt.% to 15.0 wt.% of at least one element selected from the group gallium (Ga), germanium (Ge) and indium (In), and 0.1 wt. % to 10.0% by weight of zinc (Zn).

The palladium content defines the fineness of the claimed jewelery alloy. The addition of silver or copper influences the forming properties and the color tone of the alloy. The addition of gallium, germanium and / or indium has an influence on the hardness and the melting point of the alloy. The influence of the addition of zinc on the alloy has a positive effect on forming properties and hardness.

In a further development, the jewelery alloy according to the invention additionally comprises 0.05% by weight to 5.0% by weight of tungsten (W) and / or cobalt (Co). The influence of these two elements on the alloy primarily affects the fineness of the grain and the hardness.

Finally, it is further preferred if the jewelery alloy according to the invention additionally comprises from 0.001% by weight to 1.0% by weight of at least one element selected from the group consisting of iridium (Ir), rhodium (Rh) and ruthenium (Ru). The addition of these elements also results in a finer grain size of the alloy.

In all of the above-mentioned jewelery alloys according to the invention silver contents between 10.0 wt .-% and 32.0 wt .-% are preferred with respect to the silver content. Within this range, silver contents of between 10.0% by weight and 20.0% by weight, on the one hand, or between 23.0% by weight and 32.0% by weight, on the other hand, are particularly noteworthy.

In addition, copper contents of between 3.0% by weight and 15.0% by weight are preferred with respect to the copper content of all of the abovementioned jewelery alloys according to the invention. Within this range, copper contents between 3.0% by weight and 8.0% by weight, on the one hand, or between 8.0% by weight and 15.0% by weight, on the other hand, should be particularly emphasized.

As already mentioned, the elements gallium, germanium and / or indium contained in the jewelery alloy according to the invention are known as so-called melting point depressants, ie by adding such elements, the melting point can be lowered compared to alloys. which do not contain these elements. In addition, these elements can increase the hardness of the resulting alloys.

In this connection, the content of gallium, germanium and / or indium jewelery alloys according to the invention is preferably 0.1% by weight to 3.0% by weight, in particular 0.5% by weight to 2.0% by weight. , Within the latter range, contents between 0.8% by weight and 1.6% by weight are to be emphasized.

Further, in the invention, in this connection, it is preferred that at least gallium is contained in said group of elements (gallium, germanium and indium), preferably only gallium is provided as such additive in the alloy.

The zinc content of the jewelery alloys according to the invention is preferably 0.5 wt .-% to 4.0 wt .-%, in particular 1, 0 wt .-% to 3.0 wt .-%. Within the last-mentioned range, zinc contents of between 1.2% by weight and 2.5% by weight are to be particularly emphasized.

The content of tungsten and / or cobalt is preferably 0.1 wt .-% to 2.0 wt .-%, in particular 0.1 wt .-% to 1, 0 wt .-% in the jewelery alloys according to the invention. Within the last-mentioned range, contents of tungsten and / or cobalt between 0.2% by weight and 0.6% by weight are to be particularly emphasized.

In a further development, it is preferred in the invention if the element from the group tungsten and cobalt is preferably tungsten.

As already mentioned, preferred embodiments of the invention contain at least one element from the group of iridium, rhodium and ruthenium. Such elements are, as also already known as grain refiners, because they can ensure that the resulting alloy has a lower average grain size compared to alloys that do not contain these elements.

In this context, it is preferred in the invention, when the content of iridium, rhodium and / or ruthenium from 0.02 wt .-% to 1, 0 wt .-%, in particular 0.02 wt .-% to 0.2 wt .-% is. Within the last-mentioned range, contents of iridium, rhodium and / or ruthenium of between 0.02% by weight and 0.08% by weight should be further emphasized.

According to the invention, it is preferred if at least ruthenium of the three mentioned elements iridium, rhodium and ruthenium is present, preferably only ruthenium is provided as such an additive.

In a further development, three subgroups of preferred embodiments of the palladium jewelery alloy according to the invention can be emphasized in the invention. These embodiments are grouped around the palladium fines of 585 (ie, 58.5 wt%), 600 (ie, 60.0 wt%), and 750 (ie, 75.0 wt%), with the palladium fineness embodiments of FIG 585 are particularly noteworthy.

Accordingly, there is a first group of preferred embodiments of the jewelery alloy according to the invention

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

Palladium,

25.0% by weight to 30.0% by weight of silver,

From 10.0% to 12.0% by weight of copper,

0.9 wt .-% to 1, 1 wt .-% gallium, germanium and / or indium, preferably gallium,

1, 4 wt .-% to 1, 6 wt .-% zinc, 0.3 wt .-% to 0.6 wt .-% tungsten and / or cobalt, preferably tungsten, and

0.04 wt .-% to 0.06 wt .-% iridium, rhodium and / or ruthenium, preferably ruthenium.

In particular, such a jewelery alloy consists of 58.5 wt .-% palladium, 27.85 wt .-% silver, 10.8 wt .-% copper, 1, 0 wt .-% gallium, 1, 5 wt .-% zinc , 0.3 wt.% Tungsten and 0.05 wt.% Ruthenium.

Accordingly, there is a second group of preferred embodiments of the jewelery alloy according to the invention

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

Palladium,

25.0% by weight to 30.0% by weight of silver, 8.0% by weight to 10.0% by weight of copper,

0.9% by weight to 1.1% by weight of gallium, germanium and / or indium, preferably gallium, 1.8% by weight to 2.2% by weight of zinc,

0.3 wt .-% to 0.6 wt .-% tungsten and / or cobalt, preferably tungsten, and

In particular, such a jewelery alloy consists of 60.0% by weight of palladium, 27.75% by weight of silver, 8.7% by weight of copper, 1, 0 wt .-% gallium, 2.0 wt .-% zinc, 0.5 wt .-% tungsten and 0.05 wt .-% ruthenium.

Accordingly, there is a third group of preferred embodiments of the jewelery alloy according to the invention

74.0% by weight to 76.0% by weight, preferably 75.0% by weight of palladium,

13.0% by weight to 17.0% by weight of silver, 4.5% by weight to 7.0% by weight of copper,

1.4% by weight to 1.6% by weight of gallium, germanium and / or indium, preferably gallium,

, , 8% by weight to 2.2% by weight of zinc,

0.2 wt .-% to 0.4 wt .-% tungsten and / or cobalt, preferably tungsten, and

In particular, such a jewelery alloy consists of 75.0% by weight of palladium, 15.25% by weight of silver,

5.9% by weight of copper,

1.5% by weight gallium, 2.0% by weight zinc,

0.3 wt.% Tungsten and 0.05 wt.% Ruthenium.

In a further development, the jewelery alloy according to the invention preferably has a so-called Vickers hardness of> 180 HV (annealed), in particular of 200 (± 10) HV. The Vickers hardness test is known to the person skilled in the art. HV 5 corresponds to the test load of 50 N (Newton). This specification is a common indication of the hardness of such materials in precious metal alloys.

In addition, the jewelery alloy according to the invention preferably has a specific gravity ≦ 12.0 g / cm ³ , in particular ≦ 11.5 g / cm ³ . Thus, such preferred alloys according to the invention are comparatively lightweight and therefore inexpensive materials. For comparison, known 585 white gold alloys with palladium have, for example, a specific gravity of 14.3 g / cm ³ and known 750 white gold alloys with palladium even have a specific gravity of 15.9 g / cm ³ .

Furthermore, the palladium jewelery alloy according to the invention may have a melting interval below 1250 ^° C. Preferably, such melting intervals are between 1140 ⁰ C and 1220 ⁰ C. In this context, it should be noted that alloys, in particular the alloys used in the jewelry industry, no sharp melting points, but a melting range, the so-called melting interval possess. Within this melting interval, the alloys initially soften until they increasingly liquefy and then change to the actual liquid state. For the processing of such alloys, it is therefore advantageous if such melting intervals are as low as possible, so that they can be easily melted and processed further.

Finally, the invention comprises a semifinished product for jewelery production, which is at least partially, preferably completely, made of an alloy according to the invention. As is well known, these semi-finished products are prefabricated geometric shapes made of the corresponding alloy material, which are then artificially o which are further processed industrially to the respective jewelery end products. In the jewelry sector, such semi-finished products are generally for example pipes, rods, rings, sheets, strips, wires and the like. They are first produced as a semi-finished cast product and then processed further to the final semi-finished product with the desired dimensions, preferably reshaped.

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

The invention as a whole is associated with a whole series of advantages.

Thus, as a rule, the advantages explained in the introduction, which are associated with the use of palladium, come into play. The palladium jewelery alloys according to the invention have a beautiful gray-white color with high color stability. Since the alloys are very tarnish-resistant, rhodium plating (rhodium plating) is not required unless desirable for purely aesthetic reasons. The so-called rhodium plating is known to be a chemical or galvanic coating of metals with rhodium. Such coatings are chemically and mechanically very stable and have a chrome-like gloss.

Furthermore, the alloys according to the invention have a high ductility, ie the material has a high formability before it breaks or tears. In addition, the alloys according to the invention have a fine-grained microstructure, for example with average particle sizes of less than 50 μm, in particular in the range from 20 to 35 μm. Accordingly, they can be used with both hand tools and machine tools. conditions, for example, with all common CNC (computerized numerical control) techniques, editable. This also applies to conventional inserts and diamond tools, including PCD (polycrystalline diamond).

In the alloys according to the invention, curing of at least 180 HV (Vickers hardness, calcined, ie so-called soft hardness) can readily be achieved, so that such alloys, in particular also having a palladium content of 585 (58.5% by weight), are suitable for the Production of wedding rings are suitable. In this connection, multicolored wedding rings can also be produced using the jewelery alloys according to the invention with differently colored alloys, in particular by so-called diffusion welding. In this process, metallic workpieces are joined together and with very high quality welds. The process itself and its process parameters are readily known to those skilled in the art. The alloys according to the invention can not only be processed by diffusion bonding, but also have a hardness of at least 180 HV (without deformation).

Next should again be emphasized that the specific gravity of the alloys of the invention with, in particular less than 12.0 g / cm ^3, preferably less than 1 1, 5 g / cm ³ clearly below the specific gravities of alloys of other metals comparable fineness lies. In addition, the use of palladium as a (main) alloying element makes the alloys according to the invention significantly cheaper than alloys having comparable fineness, for example to platinum.

Accordingly, the alloys of the present invention provide a low cost alternative to, for example, white gold alloys 585 gold content, wherein the alloys of the invention can also be used in combination with such alloys.

Finally, it should be emphasized that the alloys according to the invention can be produced in the conventional continuous casting process. Continuous casting is known to the person skilled in the art as a method for the production of semi-finished products from metals and alloys, whereby this method is generally carried out continuously, so that an endless strand of the desired semifinished product is provided. Since the melting intervals of the alloys according to the invention, as already mentioned, are generally below 1250 ^° C., they can be melted and processed in a simple manner with such a process. Especially in continuous casting, it is necessary to have not too high melting intervals in an alloy in order to use this method can. In continuous casting, the molten material must be sufficiently fluid for a period of time to convert the material into the strand. Too early solidification of the material must be prevented.

The described and further features of the invention will become apparent from the following example in conjunction with the subclaims. The individual features can be realized alone or in combination with each other.

example

A palladium alloy according to the invention is produced which, based on the total weight 1000 (in% o), has a fineness of palladium of 585. The individual components are as follows:

585 palladium (Pd), 278, 5 silver (Ag), 108 copper (Cu),

10 GaIIiUiTi (Ga),

15 zinc (Zn),

3 tungsten (W), and

0.5 ruthenium (Ru).

Converted to wt .-%, this alloy according to the invention thus has the composition:

58.5% by weight of palladium,

27.85% by weight of silver,

10.8% by weight of copper,

1, 0 wt .-% gallium,

1.5% by weight of zinc,

0.3 wt.% Tungsten and

0.05% by weight of ruthenium.

These ingredients are melted in an induction furnace using suitable master alloys.

The resulting alloy has a melting interval between 1145 ⁰ C and 1220 ⁰ C and can be processed accordingly in a continuous casting process to semi-finished products, in particular to pipes and rings. The hardness of the alloy is annealed (at 850 ⁰ C) 180 HV to 200 HV. The alloy has a specific gravity of 10.9 g / cm ³ . The alloy is fine-grained (mean grain size below 50 μm) and can be excellently machined (turning and milling) as well as forming, diffusion welding and polishing.

Claims

Patent claims

1. Palladium jewelry alloy comprising

58.0% by weight to 76.5% by weight of palladium,

0.5% by weight to 41.5% by weight of silver and/or copper,

0.1% by weight to 15.0% by weight of at least one element selected from the group gallium, germanium and

indium, and

0.1% by weight to 10.0% by weight zinc.

2. Palladium jewelry alloy according to claim 1 additionally comprising 0.05% by weight to 5.0% by weight of tungsten and / or cobalt.

3. Palladium jewelry alloy according to claim 1 or claim 2 additionally comprising 0.001% by weight to 1.0% by weight of at least one element selected from the group of iridium, rhodium and ruthenium.

4. Palladium jewelry alloy according to one of the preceding claims, characterized in that the silver content is between 10.0% by weight and 32.0% by weight, preferably between 10.0% by weight and 20.0% by weight. % or between 23.0% by weight and 32.0% by weight.

5. Palladium jewelry alloy according to one of the preceding claims, characterized in that the copper content is between 3.0% by weight and 15.0% by weight, preferably between 3.0% by weight and 8.0% by weight. % or between 8.0% by weight and 15.0% by weight.

6. Palladium jewelry alloy according to one of the preceding claims, characterized in that the content of gallium, Germanium and/or indium 0.1% by weight to 3.0% by weight, preferably 0.5% by weight to 2.0% by weight, in particular 0.8% by weight to 1.6 % by weight.

7. Palladium jewelry alloy according to one of the preceding claims, characterized in that the element from the group of gallium, germanium and indium is preferably gallium.

8. Palladium jewelry alloy according to one of the preceding claims, characterized in that the zinc content is 0.5% by weight to 4.0% by weight, preferably 1.0% by weight to 3.0% by weight, in particular 1.2% by weight to 2.5% by weight.

9. Palladium jewelry alloy according to one of claims 2 to 8, characterized in that the content of tungsten and / or cobalt is 0.1% by weight to 2.0% by weight, preferably 0.1% by weight to 1.0% by weight, in particular 0.2% by weight to 0.6% by weight.

10. Palladium jewelry alloy according to one of claims 2 to 9, characterized in that the element from the group of tungsten and cobalt is preferably tungsten.

11. Palladium jewelry alloy according to one of claims 3 to 10, characterized in that the content of iridium, rhodium and / or ruthenium is 0.02% by weight to 1.0% by weight, preferably 0.02% by weight. % to 0.2% by weight, in particular 0.02% by weight to 0.08% by weight.

12. Palladium jewelry alloy according to one of claims 3 to 1 1, characterized in that the element is made from the Group iridium, rhodium and ruthenium is preferably ruthenium.

13. Palladium jewelry alloy according to one of the preceding claims consisting of

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

Palladium,

25.0% by weight to 30.0% by weight of silver,

10.0% by weight to 12.0% by weight of copper,

0.9% by weight to 1.1% by weight of gallium, germanium and/or

Indium, preferably gallium,

. .4% by weight to 1.6% by weight zinc,

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

0.04% by weight to 0.06% by weight of iridium, rhodium and/or ruthenium, preferably ruthenium.

14. Palladium jewelry alloy according to claim 13 consisting of

58.5% by weight of palladium, 27.85% by weight of silver, 10.8% by weight of copper, 1.0% by weight of gallium,

1.5% by weight zinc,

0.3% by weight tungsten and 0.05% by weight ruthenium.

15. Palladium jewelry alloy according to one of claims 1 to 12 consisting of

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

Palladium,

25.0% by weight to 30.0% by weight of silver,

8.0% by weight to 10.0% by weight of copper, 0.9% by weight to 1.1% by weight of gallium, germanium and/or indium, preferably gallium, 1.8% by weight to 2.2% by weight of zinc,

16. Palladium jewelry alloy according to claim 15 consisting of

60.0% by weight palladium, 27.75% by weight silver,

8.7% by weight copper, 1.0% by weight gallium, 2.0% by weight zinc,

0.5% by weight tungsten and 0.05% by weight ruthenium.

17. Palladium jewelry alloy according to one of claims 1 to 12 consisting of

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

Palladium,

13.0% by weight to 17.0% by weight of silver,

4.5% by weight to 7.0% by weight of copper,

1.4% by weight to 1.6% by weight of gallium, germanium and/or

Indium, preferably gallium,

. .8% by weight to 2.2% by weight zinc,

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

18. Palladium jewelry alloy according to claim 17 consisting of

75.0% by weight palladium, 15.25% by weight silver, 5.9% by weight copper, 1.5% by weight gallium, 2.0% by weight zinc, 0.3% by weight. -% tungsten and 0.05% by weight ruthenium.

19. Palladium jewelry alloy according to one of the preceding claims, characterized in that the alloy has a hardness of at least 180 HV.

20. Palladium jewelry alloy according to one of the preceding claims, characterized in that the alloy has a specific gravity of less than 12.0 g/cm ³ , preferably less than 11.5 g/cm ³ .

21. Semi-finished product for jewelry production, characterized in that it is at least partially, preferably completely, made of an alloy according to one of the preceding claims.

22. Semi-finished product according to claim 1, characterized in that it is a tube-like or ring-like semi-finished product.