JPH08311583A - High purity platinum alloy - Google Patents

Abstract

PURPOSE: To provide a high purity platinum alloy capable of having practically sufficient hardness even by a casting method by incorporating specific amounts of additive elements, such as B, Si, Mg, Zr, Al, Ca, and Th, into Pt with specific purity. CONSTITUTION: This alloy is a high purity platinum alloy, containing, by weight, >=99%, preferably >=99.7%, of Pt and also containing-0.0001-1%, preferably 0.002-0.3%, in total, of one or more elements among B, Si, Mg, Zr, Al, Ca, and Th as additive elements, and conforms to mark hole Pt 1000 qualification standard. This platinum alloy can maintain the color tone and high-grade impression, inherent in Pt, even by a casting method and further can provide practically sufficient hardness, high resistance to flaw and deformation, high hardness, and excellent workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-purity platinum alloy which is used for high-purity platinum products such as rings obtained by casting, and which conforms to the certification standard of "Htmark" (Pt1000), which is a hallmark (certification stamp of the Mint Bureau of the Ministry of Finance).

[0002]

2. Description of the Related Art Heretofore, platinum (Platinum) rings, necklaces, and other accessories with a hole mark of "Pt900" have been known, and are currently available in the market. Most of the accessories are "Pt900". In the accessory with the "Pt900" hole mark, as a material, 10% by weight of palladium (P
A so-called "palladium split" platinum alloy consisting of d) and 90% by weight of platinum (Pt) is mainly used.

From the point of use, platinum is preferably used as it is as a pure metal, but platinum of extremely high purity is not only very soft and easily scratched, but also has the drawback that its workability is extremely poor because it is too soft. is there. Therefore, as described above, it is generally performed by mixing platinum with palladium or the like to form an alloy so as to have appropriate workability and mechanical strength (particularly hardness).

However, in recent years, for platinum accessories such as rings, there is a strong tendency to prefer a product with a higher degree of platinum purity that matches the image of pureness, marriage, eternity, etc., and is called "Pt900". In order to make a difference, the accessory with the hole mark "Pt1000" has begun to appear on the market.

In the platinum of "Pt1000",
It is accepted that other elements (elements other than platinum) up to 3/1000, that is, up to 0.3% by weight, are allowed as a tolerance. Platinum satisfying this standard, that is, 99.7% by weight or more is occupied by platinum element. Pt100 (Pt100 in the classification of the Hallmark of the Ministry of Finance Mint Bureau is "Pure Platinum")
A 0 "hole mark is to be added.

High-purity platinum products that meet the "Pt1000" standard are roughly classified into two types: products manufactured through plastic working and products manufactured by casting. Products manufactured through plastic working, that is, rolling, pressing, etc., have Hv (Vickers hardness) of 150 to 2 due to work hardening.
A hardness of about 00 is obtained. Since these products undergo a series of machining processes, they are limited to products with relatively simple shapes (for example, round ring, flat ring based cut ring, etc.).

The product manufactured by casting has a complicated and delicate shape because it is molded in a mold, and the casting method is preferable in order to obtain a variety of designs.

[0008]

However, in the casting method, although a complicated and delicate shape can be obtained, there is a drawback that work hardening cannot be obtained because mechanical processing such as rolling and pressing is not performed. A pure platinum product has problems such as insufficient hardness, easy deformation, and easy scratching.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-purity platinum product with a high-purity product that has a hardness sufficient for practical use even in a casting method. It is to provide a platinum alloy.

[0010]

In order to achieve the above object, the present inventor has found that high-purity platinum which has practically sufficient hardness in the casting method and which can obtain the hole mark "Pt1000". As a result of intensive research to develop alloys,
As trace elements mixed in Pt, B, Si, Mg,
By using one or more elements selected from Zr, Al, Ca and Th, “Pt100
It was found that a high-purity platinum alloy having a hardness of 0 ″ and having a practically sufficient hardness can be obtained, and the present invention has been completed.

That is, the high-purity platinum alloy according to claim 1 is
The content of Pt is 99% by weight or more, and contains B and one or more elements selected from Si, Mg, Zr, Al, Ca, and Th as additional elements. However, the total content of the additional elements is 0.0001% by weight or more and 1% by weight or less.

A high purity platinum alloy according to a second aspect of the present invention is the high purity platinum alloy according to the first aspect, which has a Pt content of 99.7% by weight or more and a total content of the additional elements of 0.002% by weight or more. It is characterized by being 3% by weight or less.

The high-purity platinum alloy according to claim 3 has a Pt content of 99% by weight or more, and B as an additional element.
Si is contained, and the total content of the additional elements is 0.0001% by weight or more and 1% by weight or less.

A high-purity platinum alloy according to a fourth aspect of the present invention is the high-purity platinum alloy according to the third aspect, wherein the Pt content is 99.7% by weight or more and the total content of the additional elements is 0.002% by weight or more. It is characterized by being 3% by weight or less.

According to the experiments conducted by the present inventor, when the Pt content is 99% by weight or more and the total content of the additional elements is 0.0001% by weight or more and 1% by weight or less, A small amount of B, Si, Mg, Zr, Al,
Due to the coexisting action with one or more elements selected from Ca and Th, the color tone and high-grade feeling of Pt are not lost even in the casting method, it is resistant to scratches and deformation, it has high hardness and workability. It was confirmed that an excellent high-purity platinum alloy can be obtained.

Further, in a cast product of a high-purity platinum alloy in which the content of Pt is 99% by weight or more and the content of additional elements is 0.002% by weight or more and 1% by weight or less, Palladium split Pt900 (Pt 90% by weight, Pd 10% by weight) Hardness of cast product (Hv = 70 to 7)
It was confirmed that the hardness of 5) or higher was obtained.

Further, the content of Pt is set to 99.7% by weight or more, and the content of the additional elements is 0.002% by weight in total.
The cast product of high-purity platinum alloy of 0.3% by weight or less is extremely resistant to scratches and deformation, has high hardness, and is excellent in workability. Furthermore, the "Pt1000" hole mark certification standard is adopted. It was confirmed that it could be satisfied.

When Si is used as an additional element,
In particular, it was confirmed that a high-purity platinum alloy that is highly resistant to scratches and deformation, has high hardness, and is excellent in workability can be obtained.

An example of the method for obtaining the high-purity platinum alloy of the present invention will be described below. B is added to Pt metal and alloyed in an arc melting furnace to produce a B-Pt alloy ingot. Next, the obtained B-Pt alloy is melted in an atmosphere of an inert gas such as Ar or N ₂ using a crucible made of SiO ₂ .

During melting, SiO ₂ which is a constituent element of the crucible and oxide refractory and B or B ₂ O ₃ react with each other, and SiO ₂ is reduced to Si. Oxidized B,
That is, since B ₂ O ₃ is vaporized and dissipated, the amount of B added to Pt is gradually reduced.

Si, which is a reduced element, and B ₂ O ₃
As a result, the hardness of Pt increases due to solid solution strengthening of B remaining in Pt without being vaporized and scattered, alloying with Pt, and various other factors, and the color tone and high-grade feeling of Pt are lost. In addition, a high-purity platinum alloy having high hardness and excellent workability can be obtained.

Besides the SiO ₂ crucible, MgO, Zr
1 selected from O ₂ , Al ₂ O ₃ , CaO, ThO ₂ etc.
Examples thereof include compounds composed of two or more kinds of compounds, but Mg instead of these crucibles made of SiO ₂ is used.
Even if a crucible composed of one or two or more compounds selected from O, ZrO ₂ , Al ₂ O ₃ , CaO, ThO ₂ and the like is used, it is the same as when the crucible made of SiO ₂ is used. The effect is obtained. That is, Zr, which is a constituent of these crucibles and is an oxide refractory during melt casting
O ₂ , MgO, Al ₂ O ₃ , CaO, ThO _{2 and the} like react with B or B ₂ O ₃ , resulting in ZrO ₂ , MgO, Al ₂ O ₃ and Ca.
O, ThO ₂ etc. are reduced to Zr, Mg, Al, Ca,
It becomes Th.

Then, B ₂ O ₃ is vaporized and dissipated, and B in Pt is dispersed.
The quantity gradually decreases. Reduced elements Zr, M
As a result of solid solution strengthening of B remaining in Pt without being vaporized and dispersed as g, Al, Ca, Th, and B ₂ O ₃ into Pt, alloying with Pt, and various other factors, the hardness of Pt is increased. And a high-purity platinum alloy having high hardness and excellent workability without losing the color tone and high-grade feeling of Pt.

[0024]

The high-purity platinum alloy according to claim 1 contains B as an additional element and one or more elements selected from Si, Mg, Zr, Al, Ca and Th. Therefore, B, which is contained in a trace amount as additional elements, Si,
By coexisting action with one or more elements selected from Mg, Zr, Al, Ca, and Th, it is resistant to scratches and deformation even in the casting method, and has high hardness and excellent workability. .

Further, since the content of Pt is 99% by weight or more and the content of the additional elements is 0.0001% by weight or more and 1% by weight or less in total, the purity of Pt becomes extremely high, The color tone and high-quality feeling of Pt can be retained.

The high-purity platinum alloy according to claim 2 has a Pt content of 99.7% by weight or more and a total content of the additional elements of 0.002% by weight or more and 0.3% by weight or less. Therefore, it is extremely resistant to scratches and deformation, has high hardness, and is excellent in workability, and further meets the certification standard of the "Pt1000" hole mark.

In the high-purity platinum alloy according to claim 3, the content of Pt is 99% by weight or more, and B is added as an additional element.
It contains Si and B as these additional elements,
Si content is 0.0001% by weight or more and 1% by weight in total
Since it is below, it is extremely resistant to scratches and deformation, has high hardness and is excellent in workability.

In the high-purity platinum alloy according to claim 4, the Pt content is 99.7% by weight or more, and the total content of B and Si as additive elements is 0.002% by weight or more.
Since it is 3% by weight or less, it is extremely resistant to scratches and deformation, has high hardness and is excellent in workability.
It conforms to the 0 ”hall mark certification standard.

[0029]

EXAMPLES The features of the present invention will be clarified below with reference to Examples and Comparative Examples. In the examples and comparative examples, the hardness was measured using a micro Vickers hardness tester with a test load of 200 g (1.96 N),
The measurement was performed under the condition that the holding time was 20 seconds. The composition analysis in this example was carried out by the curcumin absorptiometry for B, and ICP emission analysis (inductively) for other elements.
coupled plasma atomic emission spectrometry). In addition, all Pt contents (% by weight) in this example are described by effective figures with two decimal places. In addition, the Pt content takes into account 0.05% of unavoidable impurities, and B and Si, Mg, Z which are the crucible reducing elements.
The value obtained by subtraction method was subtracted from the quantitative analysis values of r and Al.

(Example 1) Commercial purity of 99.95% by weight
B having a purity of 99.50% by weight is added to Pt ingot and alloyed in an arc melting furnace so that the contents of Pt and B become 99.94% by weight and 0.0075% by weight, respectively.
An alloy ingot 1 was produced. Further, the B is added to the Pt metal and alloyed in an arc melting furnace so that the contents of Pt and B are 99.75% by weight and 0.20% by weight, respectively.
Then, a B-Pt alloy ingot 2 was prepared. Further, B is added to the Pt metal and alloyed in an arc melting furnace so that the contents of Pt and B are 99.05% by weight, respectively.
A B-Pt alloy ingot 3 containing 0.90% by weight was produced.

Next, the above-mentioned two kinds of B-Pt alloy ingots 1, 2 and 3 produced above were respectively melt-cast in a N ₂ gas atmosphere using a crucible made of SiO _{2 to} form ring-shaped castings 1, 2. And 3 were obtained. The hardness of the castings 1, 2 and 3 was Hv = 70, 232 and 267, respectively.

According to the composition analysis result, the contents of Pt, B and Si in the cast product 1 are 99.94% by weight and 0.0, respectively.
003% by weight, 0.0140% by weight, 99.
71% by weight, 0.10% by weight and 0.14% by weight, and in the cast product 3 were 99.00% by weight, 0.44% by weight and 0.51% by weight.

Further, as a result of chemical analysis, it was found that Si was reduced and alloyed in Pt as Si, not as a non-metal inclusion such as SiO ₂ . B acts as a reducing agent, and SiO _{2 of} the crucible component is reduced to Si.
Therefore, it is considered that Pt is alloyed with Pt.

In addition, the ring-shaped casting 2 is
It heat-processed in the atmosphere at 3 ° C. for 3 hours and air-cooled. The cast product 2 after heat treatment was certified by the Ministry of Finance Mint Bureau Pt1000,
passed it. After the test, the product was finished by buffing. The hardness of the finished product was Hv = 154.
In the cast product 2 after the heat treatment, the contents of Pt and B are 99.78% by weight and 0.038% by weight, respectively.
Met. The Si content was 0.13% by weight, which was not significantly different from that before the heat treatment.

(Comparative Example of Example 1) Commercial purity 99.9
A ring-shaped casting A was obtained by melting and casting 5 wt% Pt ingot in a N ₂ gas atmosphere using a crucible made of SiO ₂ . The hardness of this cast product A was Hv = 62. According to the composition analysis result, the contents of Pt and Si are 99.
It was 94% by weight and 0.012% by weight. The results of Example 1 and the comparative example of Example 1 are shown in Table 1.

[0036]

[Table 1]

From the results shown in Table 1, the hardness of the cast products 1, 2 and 3 in Example 1 was Hv = 70 to 267, and the conventional palladium split Pt900 (Pt 90% by weight, Pd).
The hardness was higher than that of the cast product (hardness Hv = 70 to 75) and the cast product A (hardness Hv = 62) of the comparative example. Further, the hardness of the cast product increased as the contents of B and Si increased. Further, the Pt content is 9
When the content of B and Si is 9.00 wt% or more and 0.0143 wt% or more and 0.95 wt% or less in total (that is, in the case of castings 1, 2 and 3), these B, Due to the coexistence of Si and Pt, it is possible to obtain a cast product of a high-purity platinum alloy that does not lose the color tone and high-grade feeling of Pt even in the casting method, is resistant to scratches and deformation, has high hardness, and is excellent in workability. Was confirmed.

Further, when the Pt content is 99.70% by weight or more and the B and Si contents are 0.0143% by weight or more and 0.24% by weight or less in total (that is, casting 1 and 2), a cast product of a high-purity platinum alloy that is resistant to scratches and deformation, has high hardness, and is excellent in workability was obtained, and further, the certification standard of the "Pt1000" hole mark could be satisfied.

Example 2 Commercial purity 99.95% by weight
B having a purity of 99.50% by weight is added to Pt ingot of No. 2 and alloyed in an arc melting furnace so that the contents of Pt and B become 99.94% by weight and 0.0075% by weight, respectively. P
A t-alloy ingot 4 was produced. In addition, B is added to the Pt metal and alloyed in an arc melting furnace to obtain Pt and B.
B-Pt alloy ingots 5 having the contents of 99.75% by weight and 0.20% by weight were produced.

Then, the above-mentioned two kinds of B-Pt alloy ingots 4 and 5 thus obtained were melt-cast in a N ₂ gas atmosphere using a crucible made of MgO to produce ring-shaped castings 4 and 5. did. The hardness of the cast products 4 and 5 was Hv = 73 and 172, respectively.

According to the results of composition analysis, the contents of Pt, B and Mg in the cast product 4 were 99.95% by weight and 0.
0005% by weight, 0.002% by weight, 99.
It was 72% by weight, 0.10% by weight and 0.13% by weight. Further, as a result of chemical analysis, it was found that Mg was reduced and alloyed in Pt as Mg, not as a non-metallic inclusion such as MgO. B or B ₂ O ₃ acts, MgO of the crucible component is reduced to Mg, and P
It is considered that it was alloyed during t.

Comparative Example of Example 2 Commercial purity 99.9
A ring-shaped cast product B was produced by melting and casting 5 wt% Pt metal in a N ₂ gas atmosphere using a crucible made of MgO. The hardness of the cast product B was Hv = 49. According to the composition analysis result, it was confirmed that the Pt content was 99.95 wt% and the Mg content in the cast product B was 0.0005 wt%.

The results of Example 2 and the comparative example of Example 2 are shown in Table 2.

[0044]

[Table 2]

From the results shown in Table 2, the hardness of the cast products 4 and 5 in Example 2 was Hv = 73 and 172, respectively, and the conventional palladium split Pt900 (Pt 90 wt%, Pd).
The hardness was higher than that of the cast product (hardness Hv = 70 to 75) or the cast product B (hardness Hv = 49) of the comparative example. Moreover, as the contents of B and Mg increased, the hardness of the cast product became higher. Further, the Pt content is 9
9.72% by weight or more and the total content of B and Mg is 0.0025% by weight or more and 0.23% by weight or less (that is, in the case of castings 4 and 5), the color tone of Pt and It was confirmed that a cast product of a high-purity platinum alloy, which does not lose a high-grade feeling, is resistant to scratches and deformation, has high hardness, and is excellent in workability, can be obtained. Furthermore, in these castings 4 and 5, "P
We were able to meet the hallmark certification standard of t1000 ".

From these results, as in the case of using the SiO ₂ crucible, MgO, which is a constituent component of the crucible and is an oxide refractory and B or B ₂ O ₃ , reacts during melting and casting, and MgO is It is reduced to Mg, and the reduced elements Mg and B ₂ O ₃ which remain in Pt without being vaporized and dispersed are solid solution strengthened in Pt, alloyed with Pt, and various other factors. Causes the hardness of Pt to increase, and P
It is considered that a cast product of a high-purity platinum alloy having high hardness and excellent workability without losing the color tone and high-grade feeling of t was obtained.

Example 3 Commercial purity 99.95% by weight
B having a purity of 99.50% by weight is added to Pt ingot of No. 2 and alloyed in an arc melting furnace so that the contents of Pt and B become 99.94% by weight and 0.0075% by weight, respectively. P
A t-alloy ingot 6 was produced. In addition, B is added to the Pt metal and alloyed in an arc melting furnace to obtain Pt and B.
B-Pt alloy ingots 7 having contents of 99.80% by weight and 0.15% by weight, respectively, were produced.

Next, the obtained B—Pt alloy ingots 6 and 7 were melt-cast in a N ₂ gas atmosphere using a crucible made of ZrO ₂ to produce ring-shaped castings 6 and 7. The hardness of the cast products 6 and 7 is Hv = 71,
It was 200.

According to the composition analysis result, the contents of Pt, B and Zr are 99.94% by weight, 0.0007% by weight and 0.0015% by weight in the cast product 6, and 99.70% by weight in the casting product 7. %, 0.04% by weight, 0.2
It was 1% by weight. As a result of chemical analysis, Zr is Zr.
Z is reduced, not as non-metallic inclusions such as O _2.
It was found to be alloyed in Pt as r. B
Alternatively, it is considered that B ₂ O ₃ acts and ZrO _{2 of} the crucible component is reduced to Zr and alloyed in Pt.

(Comparative Example of Example 3) Commercial purity 99.9
A ring-shaped cast product C was produced by melting and casting 5 wt% Pt ingot in a N ₂ gas atmosphere using a ZrO ₂ crucible. The hardness of the cast product C was Hv = 48. From the composition analysis result, it was confirmed that the Pt content was 99.95% by weight and the Zr content in the cast product C was 0.0006% by weight. The results of Example 3 and the comparative example of Example 3 are shown in Table 3.

[0051]

[Table 3]

From the results of Table 3, the hardness of the cast products 6 and 7 in Example 3 was 71 and 200, respectively, and the conventional palladium-split Pt900 (Pt90 wt%, Pd10).
% By weight) The hardness was higher than that of the cast product (hardness Hv = 70 to 75) and the cast product B (hardness Hv = 49) of the comparative example. Moreover, as the contents of B and Zr increased, the hardness of the cast product became higher. Furthermore, the Pt content is 99.70.
% Or more, and the total content of B and Zr is 0.0
When the content is 022% by weight or more and 0.25% by weight or less (that is, in the case of castings 6 and 7), Pt does not lose the color tone and high-grade feeling, is resistant to scratches and deformation, and has sufficient hardness for practical use. It was confirmed that a cast product of a high-purity platinum alloy excellent in workability was obtained. In addition, these castings 6 and 7 could satisfy the certification standard of the hole mark of "Pt1000".

From these results, as in the case of using the SiO ₂ crucible, ZrO ₂ which is a constituent component of the crucible and is an oxide refractory and B or B ₂ O ₃ reacts during melting and casting, and ZrO _{2 is used.} Is reduced to Zr, and the reduced elements Zr and B ₂ O _{3 that} have not been vaporized and dissipated and remain in Pt are solid solution strengthened in Pt, alloyed with Pt, and various other Due to factors, the hardness of Pt increases,
It is considered that a cast product of a high-purity Pt alloy having high hardness and excellent workability was obtained without losing the color tone and high-grade feeling of Pt.

Example 4 Commercial purity 99.95% by weight
B having a purity of 99.50% by weight is added to Pt ingot of No. 2 and alloyed in an arc melting furnace so that the contents of Pt and B become 99.94% by weight and 0.0075% by weight, respectively. P
A t-alloy ingot 8 was produced. In addition, B is added to the Pt metal and alloyed in an arc melting furnace to obtain Pt and B.
B-Pt alloy ingots 9 having the contents of 99.75% by weight and 0.20% by weight were produced.

Next, the obtained B—Pt alloy ingots 8 and 9 were melt-cast in a N ₂ gas atmosphere using a crucible made of Al ₂ O _{3 to} form ring-shaped castings 8 and 9.
Was produced. The hardness of castings 8 and 9 is Hv =
74 and 176.

According to the composition analysis results, castings 8 and 9
The contents of Pt, B, and Al in
At 99.94% by weight, 0.0005% by weight, 0.
0017% by weight, 99.70% by weight in casting 9,
It was 0.09% by weight and 0.19% by weight. Further, as a result of chemical analysis, it was found that Al was not reduced as a non-metallic inclusion such as Al ₂ O ₃ but was reduced and alloyed in Pt as Al. It is considered that B or B ₂ O ₃ acts, Al ₂ O ₃ of the crucible component is reduced to Al, and alloyed in Pt.

Comparative Example of Example 4 Commercial purity 99.9
A 5 wt% Pt metal was melt-cast in a N ₂ gas atmosphere using a crucible made of Al ₂ O ₃ to produce a ring-shaped cast product D. The hardness of this casting D was Hv = 48. According to the composition analysis result, the Pt content is 99.95% by weight.
It was confirmed that Al was 0.0004% by weight in the cast product D. The results of Example 4 and the comparative example of Example 4 are shown in Table 4.

[0058]

[Table 4]

From the results shown in Table 4, the hardness of the cast products 8 and 9 in Example 4 was 74 and 176, respectively, and the conventional palladium-split Pt900 (90 wt% Pt, 10 wt% Pd) cast product (hardness Hv = 70 to 75) and the cast product D (hardness Hv = 48) of the comparative example, and a higher hardness. Moreover, as the contents of B and Al increased, the hardness of the cast product increased. Furthermore, the Pt content is 99.70.
% By weight, and the total content of B and Al is 0.002
In the case of 3% by weight or more and 0.28% by weight or less (that is, in the case of castings 8 and 9), the color tone and high-grade feeling of Pt are not lost, the scratches and deformation are strong, the hardness is high, and the workability is excellent. It was confirmed that a cast product of high-purity platinum alloy was obtained. In addition, in these castings 8 and 9, "Pt100
We were able to meet the 0 ”Hallmark certification criteria.

From these results, as in the case of using the SiO ₂ crucible, Al ₂ O ₃ which is a constituent component of the crucible and is an oxide refractory and B or B ₂ O ₃ reacts during melting and casting, Al ₂ O ₃ is reduced to Al, and the reduced elements Al and B ₂ O ₃ are not vaporized and dissipated, and the remaining B in Pt is solid solution strengthened in Pt, alloyed with Pt, or Due to various other factors, the hardness of Pt increases,
It is considered that a cast product of a high-purity platinum alloy having high hardness and excellent workability without losing the color tone and high-grade feeling of Pt was obtained.

[0061]

As described above, the high-purity platinum alloy according to claim 1 contains B, which is contained in a trace amount as additional elements, and Si, Mg, and Z.
1 or 2 selected from r, Al, Ca, Th
Due to the coexistence of more than one kind of element, it is resistant to scratches and deformations, has high hardness and is excellent in workability even in the casting method or other methods.

Further, the purity of Pt is extremely high, and the color tone and high-grade feeling of Pt are maintained.

The high-purity platinum alloy according to claim 2 is extremely resistant to scratches and deformation, has high hardness, and is excellent in workability, and further meets the hole mark certification standard of "Pt1000".

The high-purity platinum alloy according to claim 3 is extremely resistant to scratches and deformation, has high hardness, and is excellent in workability.

The high-purity platinum alloy according to claim 4 is extremely resistant to scratches and deformation, has high hardness and is excellent in workability, and further conforms to the hole mark certification standard of "Pt1000".

Claims (4)

[Claims] 1. A Pt content of 99% by weight or more, and as an additive element, B and one or more elements selected from Si, Mg, Zr, Al, Ca, and Th. , And the total content of the additional elements is 0.0001% by weight or more and 1% by weight or less, a high-purity platinum alloy. 2. The Pt content is 99.7% by weight or more, and the total content of the additional elements is 0.002% by weight or more and 0.3% by weight or less. The high-purity platinum alloy described in 1. 3. The Pt content is 99% by weight or more, and B and Si are contained as additional elements, and the total content of the additional elements is 0.0001% by weight or more and 1% by weight. % Or less, a high-purity platinum alloy. 4. The Pt content is 99.7% by weight or more, and the total content of the additional elements is 0.002% by weight or more and 0.3% by weight or less. The high-purity platinum alloy described in 3.