AMORPHOUS SOLIDIFYING PRECIOUS METAL ALLOY BASED ON PRECIOUS METALS

Abstract

An amorphously solidifying noble metal alloy has the following composition of AaBbCc, wherein: A represents at least one noble metal from a group of platinum and palladium; B represents at least one element from a group of Al, Au, Ag and Cu; and C represents at least one element from a group of Ga and Ge. The mass fraction a lies in a region of 45-60 mass percent. The mass fraction b lies in the region of 39-55 mass percent. The mass fraction c lies in the region of 0-13 mass percent. Where platinum and palladium are both present, the amorphous noble metal alloy does not have aluminum as the sole alloy component from group B. The above mass fractions a, b and c, aside from typical admixtures, impurities and alloy tolerances, add up to 100 mass percent.

Claims

1. An amorphous solidifying precious metal alloy, comprising: A.sub.aB.sub.bC.sub.c, wherein: A designates at least one precious metal of a group consisting of platinum and palladium; B designates at least one element of a group consisting of Al, Au, Ag and Cu; C designates at least one element of a group consisting of Ga and Ge; wherein the mass amount a is in the range of 45 to 60 mass percent; wherein the mass amount b is in the range of 39 to 55 mass percent; and wherein the mass amount c is in the range of 0 to 13 mass percent; wherein, when platinum and palladium are simultaneously present, the amorphous solidifying precious metal alloy does not contain aluminum as a single alloy component of the group B; and wherein the aforementioned mass amounts a, b and c, apart from usual admixtures, impurities and alloy tolerances, supplement to 100 mass percent.

2. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount a is in the range of 45 to 59 mass percent.

3. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount a is in the range of 48 to 54 mass percent.

4. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount b is in the range of 39 to 49 mass percent.

5. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount b is in the range of 40 to 47 mass percent.

6. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount c is in the range of 1 to 13 mass percent.

7. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount c is in the range of 2 to 10 mass percent.

8. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass amount c is in the range of 2 to 5 mass percent.

9. The amorphous solidifying precious metal alloy according to claim 1, wherein the precious metal alloy consists of Pt.sub.a B.sub.b and C.sub.c, wherein Pt designate the precious metal platinum.

10. The amorphous solidifying precious metal alloy according to claim 1, wherein the precious metal alloy consists of Pd.sub.a B.sub.b and C.sub.c, wherein Pd designate the precious metal palladium.

11. The amorphous solidifying precious metal alloy according to claim 1, wherein the precious metal alloy consists of (Pta.sub.1 Pda.sub.2).sub.a B.sub.b C.sub.c, wherein the sum of the mass portions a.sub.1 of platinum and a.sub.2 of palladium, is—apart from usual admixtures and impurities—equal to the mass portion a.

12. The amorphous solidifying precious metal alloy according to claim 1, wherein the mass portion a is in the range of 49-51 mass percent or in the range of 50-54 mass percent, preferably in the range of 50-52 mass percent, and/or that the mass portion b is in the range of 42-47 mass percent.

13. The amorphous solidifying precious metal alloy according to claim 12, wherein the mass portion a is in the range of or in the range of 50-54 mass percent.

14. The amorphous solidifying precious metal alloy according to claim 12, wherein the mass portion a is in the range of 50-52 mass percent.

15. The amorphous solidifying precious metal alloy according to claim 1, wherein the amount of platinum or the amount of palladium is equal or greater than 50 mass percent, and/or that in the simultaneous presence of platinum and palladium the mass portion of one of these two elements is greater than 50 mass percent.

16. The amorphous solidifying precious metal alloy according to claim 1, wherein the precious metal is Pt.sub.53,2Ag.sub.31,4Cu.sub.12,2Ga.sub.3,2 or Pt.sub.50Ag.sub.33,8Cu.sub.13,2Ga.sub.3.

17. A method for the manufacturing of a semi-finished product from an amorphous solidifying precious metal alloy according to claim 1, wherein a mass portions of at least one element of the group A, b mass portions of at least one element of the group B, and c mass portions of at least one element of the group C are alloyed and cast to a semifinished product.

18. The method according to claim 17, wherein the semi-finished product is melted and is further processed in a rapid solidification process.

19. The method according to claim 18, wherein an atomization of the molten material in an inert gas is used as a rapid solidification process, or that as rapid solidification process a die-casting or a surface coating like thermic spraying or cold gas spraying is used.

20. The method according to claim 17, wherein the amorphous semi-finished product is further processed by means of a thermoplastic forming under pressure (TPF-method).

21. The amorphous solidifying precious metal alloy according to claim 1, wherein a semi-finished product for manufacturing of ornamental items comprises, at least in part, the amorphous solidifying precious metal alloy.

22. The amorphous solidifying precious metal alloy according to claim 1, wherein an ornamental article comprises, at least in part, the amorphous solidifying precious metal alloy, the ornamental article comprising a particular a piece of jewelry, a watch, a watch case, a watch band, a writing instrument or a part of such an article.

23. The amorphous solidifying precious metal alloy according to claim 1, wherein an ornamental article is completely or at least partially made from the amorphous solidifying precious metal alloy, the ornamental article comprising a particular a piece of jewelry, a watch, a watch case, a watch band, a writing instrument or a part of such an article.

24. An ornamental article, wherein the ornamental article is completely or at least partially made of an amorphous solidifying precious metal alloy, the amorphous solidifying precious metal alloy comprising: A.sub.aB.sub.bC.sub.c, wherein: A designates at least one precious metal of a group consisting of platinum and palladium; B designates at least one element of a group consisting of Al, Au, Ag and Cu; C designates at least one element of a group consisting of Ga and Ge; wherein the mass amount a is in the range of 45 to 60 mass percent; wherein the mass amount b is in the range of 39 to 55 mass percent; and wherein the mass amount c is in the range of 0 to 13 mass percent; wherein, when platinum and palladium are simultaneously present, the amorphous solidifying precious metal alloy does not contain aluminum as a single alloy component of the group B; and wherein the aforementioned mass amounts a, b and c, apart from usual admixtures, impurities and alloy tolerances, supplement to 100 mass percent.

25. The ornamental article of claim 24, wherein the ornamental article is a piece of jewelry, a watch, a watch case, a watch band, a writing instrument or a part of such an article.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Further details and advantages of the invention are disclosed in the exemplary embodiments, which are described below; the following values of amounts are mass percentages.

[0025] 1. Platinum Alloys

[0026] 1.1 System Pt—Ag—Cu

[0027] The first three exemplary embodiments of a precious metal alloy based on platinum belong to the system Pt—A—Cu.

[0028] A first exemplary embodiment of a precious metal alloy based on platinum is given by Pt.sub.53,2Ag.sub.31,4Cu.sub.12,2Ga.sub.3,2. This precious metal alloy is characterized by a favorable glass forming ability.

[0029] A second exemplary embodiment provides that the precious metal alloy is given by Pt.sub.50Ag.sub.33,8Cu.sub.13,2Ga.sub.3.

[0030] A third exemplary embodiment of a precious metal alloy is given by Pt.sub.50Ag.sub.30,6Cu.sub.11,9Ge.sub.7,5.

[0031] 1.2 System Pt—Al—Cu

[0032] The next three exemplary embodiments relate to an amorphous solidifying precious metal alloy, whose main components are Pt—Al—Cu.

[0033] The fourth exemplary embodiment is a precious metal alloy Pt.sub.53,1Al.sub.35,8Cu.sub.7,9Ga.sub.3,2. The fifth exemplary embodiment is the precious metal alloy Pt.sub.50Al.sub.38,5Cu.sub.8,5Ga.sub.3.

[0034] The sixth exemplary embodiment provides a precious metal alloy Pt.sub.50Al.sub.34,9Cu.sub.7,7Ge.sub.7,4.

[0035] 1.3 System Pt—Au—Ag—Cu

[0036] The seventh and eighth exemplary embodiment each describe a precious metal alloy of the system Pt—Au—Ag—Cu. The corresponding precious metal alloy are exemplarily given by Pt.sub.50Au.sub.23,5Ag.sub.17Cu.sub.6,5Ga.sub.3 and Pt.sub.50Au.sub.21,2Ag.sub.15,3Cu.sub.6Ge.sub.7,5.

[0037] The afore-mentioned eight exemplary embodiments therefore describe amorphous solidifying precious metal alloys based on platinum, which are characterized by the following composition: Pt.sub.a B.sub.b C.sub.c, whereby Pt stands for platinum, B characterizes at least one element of a group consisting of Al, Au, Ag, and Cu, and C defines at least one element of a group consisting of Ga and Ge. The parameter a stands for the platinum amount of the described precious metal alloy with 45-60 mass percent, the parameter b for 39 to 55 mass percent, preferably 39-49 mass percent, and the parameter c for 0-13 mass percent.

[0038] It is preferred that platinum is present in an amount of 45-60 mass percent, preferably between 45 and 59 mass percent, further preferably between 48-54 mass percent, in particular in an amount of 49 to 51 mass percent or 50-54 mass percent and for the last range in particular in an amount of 50-52 mass percent in the described precious metal alloy. The last mentioned ranges are characterized by a particularly favorable glass forming ability.

[0039] The amount b of the one or of several metals of the group B is between 39 to 55 mass percent, preferably 39-49 mass percent, preferably 40-47 mass percent and in particular 42-47 mass percent.

[0040] It is preferred that at least one of gallium and/or germanium is present in an amount c between 0-13 mass percent, preferably in an amount of 1-13 mass percent, preferably in an amount of 1-12 mass percent and here in particular between 2-10 mass percent and further in particular 2 to 5 mass percent in the described precious metal alloy. It is possible, but not preferred, that at least one of gallium and/or germanium is present in an amount c of 0-1 mass percent, so that in an extreme case (c=0) gallium and/or germanium is not contained in the afore described precious metal alloy.

[0041] 2. Palladium Alloys

[0042] As mentioned at the beginning, it has surprisingly been shown that not only amorphous solidifying precious metal alloys based on platinum with the afore described composition exhibit the advantageous properties, but that platinum can be completely or partially substituted by palladium.

[0043] 2.1 System Pd—Ag—Cu

[0044] The ninth exemplary embodiment is a precious metal alloy associated to the system Pd—Ag—Cu and consists of Pd.sub.50Ag.sub.34Cu.sub.13Ga.sub.3. In this case too, a favorable glass forming ability is given.

[0045] 2.2 System Pd—Au—Ag—Cu

[0046] An exemplary embodiment of a precious metal alloy associated to this system is Pd.sub.50Au.sub.20,2Ag.sub.14,6Cu.sub.5,7Ge.sub.9,5.

[0047] 2.3

[0048] The afore described precious metal alloy can be characterized by Pd.sub.a B.sub.b C.sub.c, whereby Pd stands for palladium and B and C once more for at least one element of the afore-mentioned groups Al, Au, Ag, Cu and Ga, Ge respectively.

[0049] The amount a of palladium is once more between 45-60 mass percent, preferably 45-59 mass percent, further preferably 48-54 mass percent, further preferably 49-51 mass percent or 50-54 mass percent and hereby preferably 50-52 mass percent, whereby in particular in the last mentioned concentration ranges a particularly favorable glass forming ability is given.

[0050] The amount b of the one or the elements of the group B is between 39 to 55 mass percent, preferably 39-49 mass percent, further preferably 40-47 mass percent and hereby further preferably 42-47 mass percent.

[0051] The amount of gallium and/or germanium once more is between 0-13 mass percent, whereby the preferred ranges, which are specified above under no. 1 for the amorphous precious metal alloys based on platinum apply for palladium correspondingly.

[0052] It is preferred that the ratio of the atomic proportions of palladium and aluminum is equal or greater 4. This atomic ratio of palladium to aluminum corresponds to a mass ratio of palladium to aluminum of equal or greater 94/6; therefore it is preferred that the ratio of the amounts of palladium and aluminum is—expressed in mass ratios—equal or greater 15,67. An example for such an alloy is given by an alloy, which contains 45 to 60 mass percent palladium, 39 to 55 mass percent of at least two elements of the group B and at least one of gallium and/or germanium in an amount of 0 to 13 mass percent, but with the following condition: the first of the at least two metals of the group B is aluminum, whereby aluminum—corresponding to the amount of palladium in the range between 45 to 60 mass percent and the afore-mentioned ratio between palladium and aluminum—is present in an amount of at maximum 45/15,67 to 60/15,67, i. e. in an amount of 2,87 to 3,83 mass percent; the rest of the amount b of the at least two elements of the group B is then provided by a further element of the afore-mentioned group B. As in the cases described above, the preferred ranges for the amounts a, b and c apply here correspondingly.

[0053] 3. Platinum-Palladium-Alloys

[0054] A precious metal alloy, which does not only contain platinum or palladium alone, but a combination of platinum and palladium—(Pt.sub.a1 Pd.sub.a2)a in an amount a=a.sub.1+a.sub.2 of 45-60 mass percent and in addition the afore-mentioned components, in which platinum is substituted by palladium up to 100 wt.-%, exhibits the afore-mentioned advantageous properties too, in particular in respect to the glass forming ability. As an example for such a precious metal alloy Pd.sub.50Pd.sub.3,2Ag.sub.31,4Cu.sub.12,2Ga.sub.3,2 is to be mentioned.

[0055] The platinum-palladium-alloys are characterized by (Pt.sub.a1 Pd.sub.a2)a B.sub.b C.sub.c, whereby for the mass amounts a, b and c once more the values disclosed in sections 1.3 and 2.3 apply.

[0056] It is once more preferred that the ratio of the atomic amounts of palladium and aluminum is equal or greater than 4. The explanations at the end of section 2.3 also apply for a combination of platinum and palladium correspondingly. As exemplary embodiment the following alloy is to be stated: Such alloy contains platinum and palladium in a total amount of 55 mass percent, whereby it is assumed that 50 weight percent platinum and 5 weight percent palladium are present. The amount of elements of the group B, here exemplarily aluminum and copper, is between 40 and 45 mass percent, whereby, if appropriate, a corresponding amount c of elements of the group C is contained. The amount of aluminum then is less than 0,32 mass percent and the amount of copper is in the range between 39,7 to 24,7 mass percent.

[0057] It is preferred that in the case when platinum and palladium are simultaneously present, one of these two elements, i. e. platinum or palladium, is present in an amount of more than 50 mass percent, in order to maintain the hallmarking capability of such a precious metal alloy with at least 50 mass percent of platinum or palladium, or in an amount of slightly less than 50 mass percent. As an example, the amount of platinum, assuming that the total amount of platinum and palladium is of 51-60 mass percent together, can be 50-59 mass percent, this means that palladium then is present in an amount of 1 mass percent only. The same applies vice versa, namely, that—once more as an example—palladium is present in an amount of 50-59 mass percent and hence the amount of platinum is only 1 mass percent. Of course any combinations are possible, e. g. that the amount of platinum and palladium respectively is 50-54 mass percent, preferably 50-52 mass percent, at a total amount of platinum and palladium of e. g. 59 mass percent, and the rest of the each other metal is then the amount lacking to 59 mass percent.

[0058] In the foregoing description of the exemplary embodiments of the amorphous platinum-palladium alloys it was assumed that several elements of the group B, i. e. of the group consisting of Al, Au, Ag, Cu, is present. But it is possible too that only one of these elements, as a single alloy element, of the group B is present in the described precious metal alloys. But it is preferred that aluminum is not present as the only element of group B. A combination of elements of the group B, which contains Al, is possible in said amorphous platinum-palladium alloys, as well as in the afore described amorphous platinum alloys and the amorphous palladium alloys. This is especially true when the amount a of platinum and palladium is between 45 and 59 mass percent, and is in the afore described sub ranges of the amount a.

[0059] 4. Manufacturing and Further Processing

[0060] The manufacturing of the afore-mentioned precious metal alloys is, as an example, illustrated with reference to the first embodiment. Manufacturing of the further precious metal alloys having the composition A.sub.a B.sub.b C.sub.c is done correspondingly: For the manufacturing of the precious metal alloy of the first exemplary embodiment 53,2 mass percent platinum, 31,4 mass percent silver, 12,2 mass percent copper and 3,2 mass percent gallium are alloyed and casted to form a massive semi-finished product. The semi-finished product is then melted in the next step and processed by a rapid solidification process. Preferred is an atomization of the melted mass in a flow of inert gas by means of a method and a device, which is e. g. described in the German patent DE 103 40 606 B4.

[0061] In an atomization of the melted mass with a starting temperature of 1250° C. in a nitrogen stream with a discharge pressure of 10 bar the material solidifies in splits of a second in the form of amorphous powders, which typically have an average particle diameter of 25 μm. The amorphous powder has got a glass transition temperature T.sub.g of approximately 290° C. and a crystallization temperature T.sub.x of approximately 450° C.

[0062] Further rapid solidification processes are a die-casting as well as a surface coating process such as thermal spraying or cold gas spraying.

[0063] The further processing of the plastified amorphous semi-finished product masses at temperatures above the glass transition temperature by means of the so called thermoplastic forming under pressure (TPF-method), as e. g. the die-casting of plastified amorphous semi-finished product masses by temperatures above the glass transition temperature is possible.

[0064] It is evident for the person skilled in the art from the above description that the ranges specified in each case apply in the context of conventional alloy tolerances. In addition, it is evident for him that by specifying the range limits all mass portions falling in the respective range are encompassed too.

[0065] In conclusion, it is to be stated that the described precious metal alloy is in particular suited for the manufacturing of ornamental articles such as jewelry items, watches, watch cases, writing instruments and components of the afore-mentioned goods.