JPH08295968A - Gold alloy for decoration - Google Patents

Abstract

PURPOSE: To produce a gold alloy for decoration having a color tone equal to that of pure gold and having high hardness by constituting a gold alloy for decoration of a compsn. contg. specified amounts of Sr and Ba, and the balance Au with inevitable impurities. CONSTITUTION: A gold alloy is melted and cast using, for example, a gold master alloy contg. pure gold having 99.995% purity and 0.1 to 1% Sr and/or Ba as alloy elements. This is subjected to etching by aqua regia and is thereafter worked. The compsn. of the gold alloy is constituted of the one contg., by weight, 0.001 to 0.2% Sr and/or Ba, and the balance >=99% Al with inevitable impurities. Moreover, one or more kinds selected from a group of Ge, Y and rare earth elements may be incorporated therein by <=0.1%. In addition to the same, Ca, Ru or the like may be incorporated therein. Thus, the gold alloy sufficiently maintaining high hardness even by heating in brazing or so can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gold alloy suitable for use as a decorative member.

[0002]

2. Description of the Related Art Gold alloys are used for decorative members such as necklaces and rings because of their good corrosion resistance, high-quality color tone, good ductility and high asset value. Such an ideal gold alloy for decoration is ideally, for example, an alloy close to pure gold having 99% by weight or more, or an alloy having pure gold having 99.99% by weight or more, but an alloy having an alloy close to pure gold or a pure gold usually has hardness. It is not used very often because it has a low value and is easily scratched. Therefore, conventionally, a gold alloy having a high hardness to which an alloying element such as Cu is added by about several wt% has been used as a decoration gold alloy. Of the above ideal ornamental gold alloys, gold is 9
As a gold alloy having a hardness of 9% by weight or more, which is close to the original color tone of gold and has a high hardness, there is known a gold alloy capable of obtaining a high hardness in the state of a processed material (see JP-A-6-179931). . Further, it is known that 99% by weight or more of gold is added to a rare earth element containing Y (Japanese Patent Laid-Open No. 7-7067).
No. 0 publication). However, the hardness of these gold alloys decreases even when heated at a temperature of brazing, and the hardness decreases with time even when kept at room temperature.

[0003]

Therefore, in view of the above circumstances, an object of the present invention is to have 99% by weight or more of gold, have a high hardness at room temperature, and even heat at a temperature of brazing as much as possible. It is an object of the present invention to provide a decorative gold alloy that can maintain high hardness, that is, that has excellent heat resistance.

[0004]

The present invention achieves the above object, and the first one thereof contains 0.001 to 0.2% by weight of Sr and / or Ba, and the balance 99
A decorative gold alloy comprising Au and inevitable impurities in an amount of at least 9% by weight, preferably at least 99.8% by weight. A second aspect of the present invention is that Sr and / or Ba is 0.001 to 0.001.
A containing 0.2% by weight and 0.1% by weight or less of one or more kinds selected from the group consisting of Ge, Y and rare earth elements, and the balance of 99% by weight or more, preferably 99.7% by weight or more.
It is a gold alloy for decoration consisting of u and unavoidable impurities. The third aspect of the present invention is to add Sr and / or Ba to 0.0
01 to 0.2% by weight and 0.1% by weight or less of Ca, the balance 99% by weight or more, preferably 99.7% by weight
It is a decorative gold alloy composed of the above Au and inevitable impurities. And the fourth aspect of the present invention is selected from the group consisting of 0.001 to 0.2% by weight of Sr and / or Ba, 0.1% by weight or less of Ca, and Ge, Y and a rare earth element. Au in an amount of 0.1% by weight or less and 99% by weight or more, preferably 99.6% by weight or more.
And a gold alloy for decoration consisting of inevitable impurities.

A fifth aspect of the present invention is that Ru is less than 0.
A decorative gold alloy containing 1 to 0.3% by weight and the balance of 99% by weight or more, preferably 99.7% by weight or more of Au and inevitable impurities, and Ru finely precipitated. And the 6th thing of this invention makes Ru 0.1-0.1.
0.3% by weight and 0.05 or more selected from the group consisting of Ca, Sr, Ba, Ge, Y and rare earth elements.
% Or less, the balance 99% or more, preferably 9%
A gold alloy for decoration, which is composed of 9.65% by weight or more of Au and unavoidable impurities and in which Ru is finely precipitated.

[0006]

First, the decorative gold alloys of the first to fourth inventions will be described. Sr and Ba have the effect of improving the hardness and heat resistance of the decorative gold alloy of the present invention, and the addition amount of Sr and / or Ba is 0.001% by weight (hereinafter, the weight% of the composition is simply referred to as%). If it is less than (1), the above-mentioned action is not sufficient, while if it exceeds 0.2%, not only the above-mentioned action is not further increased, but also the gold purity and melt castability of the gold alloy are deteriorated. In the second and fourth inventions, Ge has a function of preventing the ductility of the gold alloy from decreasing and stabilizing various properties of the gold alloy regardless of the manufacturing process, and Y and the rare earth element are gold alloys. Has the effect of improving the heat resistance of. If the added amount of one or more selected from the group consisting of Ge, Y and rare earth elements exceeds 0.1%, not only the above action is not further enhanced, but also the gold purity of the gold alloy is lowered. In order to fully exert the action of one or more selected from the group consisting of Ge, Y and rare earth elements, the lower limit of the amount of addition of these elements is preferably 0.0001%.
In the third and fourth inventions, Ca has an effect of improving the heat resistance of the gold alloy, and when the addition amount of Ca exceeds 0.1%, not only the above effect is not further increased, but also that of the gold alloy. Purity and melt castability are reduced. In order to fully exert the action of Ca, the lower limit of the amount of Ca added is
0.001% is preferable.

Next, the decorative gold alloys of the fifth and sixth inventions will be described. In these decorative gold alloys, the added Ru finely precipitates in the Au matrix and is precipitation hardened. Ru has the effect of improving the hardness and heat resistance of the decorative gold alloy of the present invention, and if the addition amount of Ru is less than 0.1%, the above effect is not sufficient, while
When it exceeds 0.3%, the gold purity of the gold alloy is lowered although it has the above effect. In the sixth invention, Ca, Y and the rare earth element have an action of improving the heat resistance of the gold alloy, and Sr and Ba have an action of improving the hardness and the heat resistance of the gold alloy. Ge has the function of preventing the ductility of the gold alloy from decreasing and stabilizing the various properties of the gold alloy regardless of the manufacturing process. Ca, Sr, Ba, Ge, Y
When the amount of one or more selected from the group consisting of and rare earth elements exceeds 0.05%, not only the above-mentioned action is not further enhanced, but also the gold purity of the gold alloy is lowered. In order to fully exert the action of one or more selected from the group consisting of Ca, Sr, Ba, Ge, Y and rare earth elements, the lower limit of the amount of addition of these elements is preferably 0.001%.

Au of the ornamental gold alloys of the fifth and sixth inventions
In order to finely precipitate Ru in the matrix of
The ingot or the intermediate material obtained by plastically working the ingot may be subjected to solution treatment and heat treatment for age hardening. As conditions for the solution treatment, it is preferable that the temperature is about 700 to 1000 ° C. and the time is about 30 minutes to 2 hours. However, depending on the type and amount of the alloy element to be added, when the cooling rate of the ingot is sufficiently high, it is possible to obtain the same effect as that when the solution treatment is performed when cooling the ingot. As conditions for heat treatment for age hardening, a temperature of about 150 to 400 ° C. and a time of about 10 minutes to 4 hours are preferable. However,
Depending on the type and amount of alloying elements added, by appropriately adjusting the cooling rate of the ingot, the same effect as the heat treatment for solution heat treatment and age hardening is performed when cooling the ingot. Obtainable. In the ornamental gold alloys of the first to sixth inventions, unavoidable impurities include Pt and P.
platinum group metals such as d, Ag, Cu, Ni, Fe, In,
Sn, Sb, Zn, Si, Mn, Cr, Ti, Be, S
Examples thereof include c and Mg, but these elements may also contribute to the improvement of the hardness of the gold alloy to some extent.

[0009]

【Example】

[Examples 1 to 16 and Comparative Example 1] Manufacturing tests of Examples and Comparative Examples of the decorative gold alloys of the first to fourth inventions were conducted. Using pure gold having a purity of 99.995% and a gold mother alloy containing 0.1 to 1% of alloy elements, 0.1 to 1 of the alloy elements shown in Table 1 is used.
%, The gold alloy containing the alloy elements shown in Table 1 in the amounts shown in Table 1 was melt-cast. The surface of the obtained ingot was etched with aqua regia, and then the ingot was processed into 8 mm square by groove roll rolling. After this intermediate material of 8 mm square was subjected to intermediate annealing, wire drawing was performed to obtain wire materials having a diameter of 1.5 mm and a diameter of 0.3 mm. A wire rod with a diameter of 1.5 mm is used as it is for micro Vickers hardness H _V (load 100
g) was measured, the wire was further immersed in a salt bath at 200 ° C. for 30 minutes and heated, and then the micro Vickers hardness H _V (load 100 g) was measured again. This evaluated the hardness and heat resistance of the gold alloy. The wire rod having a diameter of 0.3 mm was subjected to a tensile test with a sample length of 10 cm to measure the elongation at break. This evaluated the ductility of the gold alloy. The results obtained are shown in Table 1.

[0010]

[Table 1] Note: "-" in the composition column indicates no addition.

[Examples 17 to 26, Comparative Example 2] Manufacturing tests of Examples and Comparative Examples of the decorative gold alloys of the fifth and sixth inventions were conducted. Using a gold master alloy containing 99.995% pure gold and 0.1 to 3% of alloy elements, a gold alloy containing the alloy elements shown in Table 2 in the amounts shown in Table 2 was melt-cast. For the casting, a heated graphite mold was used, and the ingot had a width of 30 mm,
The shape was 5 mm thick and 100 mm long. The obtained ingot was cut into a length of 10 mm, and then subjected to solution treatment and heat treatment for age hardening under the conditions shown in Table 2 in an electric furnace in the air atmosphere. In the solution treatment, the sample was heated and then quenched into water. The obtained sample was directly measured for micro Vickers hardness H _V (load 100 g), further, the sample was immersed in a salt bath at 200 ° C. for 30 minutes and heated, and then the micro Vickers hardness H _V (load 10 g was again applied.
0 g) was measured. This evaluated the hardness and heat resistance of the gold alloy. The obtained results are shown in Table 2.

[0012]

[Table 2] Note (1): "-" in the composition column indicates no addition. Note (2): The heating time in the solution treatment is 60 minutes in all cases.

Comparative Example 3 Using pure gold having a purity of 99.995% and electrolytic copper, a gold alloy containing 0.38% of Cu was melt-cast. After that, a gold alloy wire rod was obtained in the same manner as in Example 1, and its hardness and heat resistance were evaluated. Table 3 shows the obtained results.

[0014]

[Table 3]

From the results of the above Examples and Comparative Examples, the following can be understood. That is, (1) the gold alloys of the examples had a micro Vickers hardness H _v of 97 to 159 when produced, and had a high hardness of about 100 or more, and the hardness did not easily decrease even when heated at 200 ° C. Is also excellent. In particular, alloy elements such as Ca, Y, La, Eu, which are effective for improving the heat resistance,
When a rare earth element such as Yb or Ce is added (Example 7)
~ 16, 20-26), the heat resistance is extremely improved. Further, when Ge, which is an alloying element effective for improving the ductility, is added (Examples 6, 13, and 14), the breaking elongation is significantly improved. In addition, among the gold alloys of Examples, Examples 1, 6, 9 and 13 can be said to be pure gold with 99.99% or more of gold, and even with such high grades, high hardness and excellent Has heat resistance. (2) In the alloys of Comparative Examples 1 and 2, sufficient addition of alloying elements (Ba, Ru) effective to improve hardness is insufficient, and sufficient hardness cannot be obtained. (3) The alloy of Comparative Example 3 has Cu added as an alloying element and contains 99% or more of gold, but the hardness when manufactured is 200 ° C. even if the micro Vickers hardness H _v is 100 or more. When heated, the hardness is extremely reduced.

[0016]

According to the present invention, 99% or more of gold has a color tone equal to or close to that of pure gold, has a high hardness at room temperature, and sufficiently retains this high hardness even when heated to a temperature of brazing. Then, the micro Vickers hardness H _v is 100.
A decorative gold alloy having a degree or more can be provided.

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[Procedure amendment]

[Submission date] June 7, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

EXAMPLES [Examples 1 to 16 and Comparative Example 1] Manufacturing tests of Examples and Comparative Examples of the decorative gold alloys of the first to fourth inventions were conducted. Using a pure gold having a purity of 99.995% and a gold mother alloy containing 0.1 to 1% of alloy elements, a gold alloy to which the alloy elements shown in Table 1 were added in the amounts shown in Table 1 was melt cast. The surface of the obtained ingot was etched with aqua regia, and then the ingot was processed into 8 mm square by groove roll rolling. After this intermediate material of 8 mm square was subjected to intermediate annealing, wire drawing was performed to obtain wire materials having a diameter of 1.5 mm and a diameter of 0.3 mm. The wire having a diameter of 1.5 mm was directly measured for micro Vickers hardness H _v (load 100 g), further, the wire was immersed in a salt bath at 200 ° C. for 30 minutes and heated, and then the micro Vickers hardness H _{v was} again measured.
(Load 100 g) was measured. This evaluated the hardness and heat resistance of the gold alloy. The wire rod having a diameter of 0.3 mm was subjected to a tensile test with a sample length of 10 cm to measure the elongation at break. This evaluated the ductility of the gold alloy. The results obtained are shown in Table 1.

Claims (11)

[Claims] 1. Sr and / or Ba in an amount of 0.001 to
A decorative gold alloy containing 0.2% by weight and the balance 99% by weight or more of Au and inevitable impurities. 2. The decorative gold alloy according to claim 1, wherein the balance comprises 99.8% by weight or more of Au and inevitable impurities. 3. Sr and / or Ba in an amount of 0.001 to
A decorative gold alloy containing 0.2% by weight and 0.1% by weight or less of one or more kinds selected from the group consisting of Ge, Y and rare earth elements, and the balance 99% by weight or more of Au and inevitable impurities. 4. Sr and / or Ba in an amount of 0.001 to
A decorative gold alloy containing 0.2% by weight and 0.1% by weight or less of Ca, and the balance 99% by weight or more of Au and inevitable impurities. 5. The decorative gold alloy according to claim 3, wherein the balance comprises 99.7% by weight or more of Au and inevitable impurities. 6. Sr and / or Ba in an amount of 0.001 to
0.2 wt%, Ca 0.1 wt% or less, Ge,
A decorative gold alloy containing 0.1% by weight or less of at least one selected from the group consisting of Y and rare earth elements, and the balance 99% by weight or more of Au and inevitable impurities. 7. The decorative gold alloy according to claim 6, wherein the balance comprises 99.6% by weight or more of Au and inevitable impurities. 8. A Ru content of 0.1 to 0.3% by weight with the balance being 99% by weight or more of Au and inevitable impurities.
And a gold alloy for decoration in which Ru is finely precipitated. 9. The decorative gold alloy according to claim 8, wherein the balance comprises 99.7% by weight or more of Au and inevitable impurities. 10. Ru of 0.1 to 0.3% by weight and C
a, Sr, Ba, Ge, Y, and at least one selected from the group consisting of rare earth elements in an amount of 0.05 wt% or less, the balance being 99 wt% or more Au and inevitable impurities,
And a gold alloy for decoration in which Ru is finely precipitated. 11. The decorative gold alloy according to claim 10, wherein the balance comprises 99.65% by weight or more of Au and inevitable impurities.