JP4417166B2 - Decorative silver alloys and ornaments - Google Patents

Description

  TECHNICAL FIELD The present invention relates to silver alloys and ornaments for various decorations such as jewelry such as rings and brooches, tableware, upholstery, and the like. The present invention relates to a decorative article in which the surface of a base material is coated with the silver alloy.

Silver and silver alloys are excellent in electrical resistance, contact resistance, high-frequency characteristics, solderability, sliding characteristics, etc., and they are excellent in appearance and safer than being used for sliding parts and electrical circuits. Therefore, it is also used for jewelry such as rings and necklaces, tableware and ornaments.
However, silver is a metal that is prone to discoloration and corrosion, and it is well known that these are particularly remarkable in environments containing sulfur-containing compounds. Resistance to sulfur-containing compounds, that is, resistance to sulfidation, is a major characteristic that decorative silver alloys should have. Conventionally, attempts have been made to improve the resistance to sulfidation by studying the types and compositions of alloy constituent metals. Yes. Further, characteristics desirable to have as a decorative silver alloy include processability (high hardness) and moisture resistance.
JP 2001-192753 (paragraph 0023, Table 2 sample No. 39)

In Patent Document 1, germanium (instead of copper or together with copper) is used in order to eliminate the sulfidation resistance and workability which are disadvantages of a silver (Ag) -copper (Cu) alloy which is a conventional decorative silver alloy. A decorative silver alloy to which Ge) or indium (In) -Ge is added, for example, a quaternary alloy of Ag-In-Ge-Cu is described.
However, this quaternary alloy is inferior in moisture resistance among the properties required for decorative silver alloys, and when left under high humidity for a long period of time, even if the surface becomes cloudy or does not become cloudy, the surface gloss is lost and the decorative material As its value is greatly diminished. The white turbidity is caused by the influence of chlorine ions contained in the moisture in the air, but since it does not appear as noticeably in appearance as the discoloration or corrosion caused by sulfur-containing compounds, it has hardly been a problem in the past.

However, as long as it is used for decoration, deterioration of the appearance is a big problem, and if a silver alloy that hardly causes white turbidity is developed, it can be used as a more preferable decorative silver alloy.
The inventor studied the constituent metals of the quaternary alloy, found a decorative silver alloy with improved moisture resistance, which was a drawback of the quaternary alloy, without significantly deteriorating other characteristics, and reached the present invention It is.
Accordingly, an object of the present invention is to provide a silver alloy having excellent moisture resistance for decoration, particularly for jewelry.

The present invention is a decorative silver alloy consisting of 0.10 to 10% by weight of palladium, 0.10 to 5.0% by weight of copper, 0.10 to 10% by weight of germanium and the balance silver and having moisture resistance. is there.

The present invention will be described in detail below.
According to the study of the present inventor, the above-mentioned conventional quaternary alloy has poor moisture resistance in the range of 400 to 650 nm, particularly 500 to 600 nm in the visible light region of about 400 to 800 nm, and is kept in a high temperature and high humidity atmosphere for several hours. It was confirmed that the reflectance drop of about 30% at maximum occurs just by placing.
Accordingly, the inventor of the present invention has proposed a metal alloy other than Ag as a base metal of the quaternary alloy, that is, moisture resistance of a silver alloy obtained by substituting In, Ge, and Cu with other metals or removing them from the alloy structure. As a result of measurement, it was found that an Ag—P d— Cu—Ge alloy obtained by replacing In with P d has good moisture resistance in substantially all the visible light region.

This decorative silver alloy of the present invention has good moisture resistance in the visible light range of about 400 to 800 nm, and there is almost no surface deterioration (decrease in reflectivity) even when left in a high temperature and high humidity atmosphere. When used for decoration, especially for jewelry such as rings, necklaces, pendants and bracelets, the surface thereof is maintained in the initial state or in a state close thereto, and the value as a jewelry product can be maintained for a long time.
The silver alloy for decoration of the present invention may be formed into a shape of a decorative article, or may be formed as a decorative article by coating the surface of a decorative article substrate formed into a predetermined shape by plating or sputtering.
The use of the silver alloy of the present invention includes various metal ornaments, and in addition to the above-mentioned jewelry, there are a watch belt, tableware, a metal container, such as a metal vase.

Above As mentioned, by replacing the conventional In the Ag-In-Cu-Ge alloy is decorative silver alloy P d, conventionally present invention moisture resistance was hardly noted improved An Ag—P d— Cu—Ge alloy can be provided. From the use of the alloy of the present invention as a decorative silver alloy, the quality of the surface state is the commercial value itself, and the usefulness of the silver alloy of the present invention with improved moisture resistance that greatly affects the surface state is great.

  Next, although this invention is demonstrated in detail based on embodiment, this invention is not limited to these.

The decorative silver alloy of the present invention contains Ag as a main component and essential four components of Ag, Pd, Ge, and Cu. Furthermore, inevitable impurities may be mixed.
The content of Pd is 0.10 to 10% by weight, preferably 0.30 to 5% by weight. If the amount is less than 0.1% by weight, the effect of addition is not sufficiently exhibited. This is because the quality of the color tone is lowered. The Cu content is 0.10 to 3.0% by weight, more preferably 0.30 to 3.0% by weight, and if it exceeds 5.0% by weight, the quality of the color tone may be lowered. Cu has a function of imparting hardness to the added alloy, and it is desirable that the decorative alloy, particularly a jewelry alloy, has a high hardness in order to prevent surface sagging and product surface damage during molding. The Cu content may denseness and hardness is lowered is less than 0.10 wt%, Cu content shall be the 0.10 wt% or more. The Ge content is 0.10 to 10% by weight, preferably 0.10 to 5.0% by weight. When the content is 0.10% by weight, the sulfidation resistance is lowered. Because it goes down. Cu and Ge within these ranges have excellent heat resistance due to their synergistic effect, and sulfur resistance is improved by the action of Ge.

The Ag—P d— Cu—Ge alloy of the present invention thus obtained has excellent moisture resistance. For example, in an Ag—Pd—Cu—Ge alloy containing 1 to 3 wt% of Pd, The drop in reflectance is usually about 5% at maximum when left in a high temperature and high humidity atmosphere for 5 hours. On the other hand, the Ag—In—Cu—Ge alloy may reach nearly 30%.
Therefore , by substituting In in the Ag-In-Cu-Ge alloy, which is a conventional decorative silver alloy, with Pd to obtain an Ag-P d- Cu-Ge alloy, the moisture resistance is greatly improved. Long-term stability is greatly improved.

The reason why the Ag—P d— Cu—Ge alloy obtained by substituting In in the conventional silver alloy with P d according to the present invention is superior to the In alloy in moisture resistance (in other words, there is little reduction in reflectivity). but not, the particle size of P d containing chromatic alloy is miniaturized than that of in-containing alloys can guess a factor. That is an indication of the finer particles Ra (average surface roughness) and P-V (maximum height difference) is, (which means the progress of miniaturization) strong decrease trend P d containing chromatic alloy This refinement is considered to contribute to the improvement of moisture resistance.
The production of the silver alloy of the present invention may be carried out according to a conventional method, and a target metal alloy is obtained by melting and mixing a metal ingot weighed to have a predetermined composition.

[Example 1]
97.0Ag-1.0Pd-1.0Cu-1.0Ge (Ag 97.0% by weight, Pd 1.0% by weight, Cu 1.0% by weight and Ge 1.0% by weight) In this way, the same is applied to the carbon crucible having a low oxygen content. This crucible was put into a high frequency melting furnace, the inside of the furnace was evacuated to a vacuum of 1.33 Pa using a vacuum pump, and Ar gas was introduced to adjust the degree of vacuum to about 5 × 10 ⁴ Pa. The melting furnace was heated to 1050 to 1400 ° C. (average temperature about 1200 ° C.) to start melting, and after the molten state was stabilized, the melt was poured into a mold to prepare an ingot.

This ingot was heat-treated at 600 to 900 ° C., subjected to hot forging and rolling, and the surface and outer periphery were cut with a lathe to obtain a sputtering target material.
Using this sputtering target material, a silver alloy-coated substrate of Example 1 was formed by sputtering on a quartz glass substrate surface having a smooth surface by a sputtering method to a film thickness of 200 nm. This silver alloy coated substrate was annealed in air at 250 ° C. for 1 hour. FIG. 1A shows an AFM (atomic force microscope, manufactured by SII, model number SPA300HV) image (about 30,000 times) of the thin film on the surface of the substrate. The Ra (average surface roughness) of the silver alloy shown in this image was 1.246 nm and PV (maximum height difference) was 15.77 nm.

The silver alloy-coated surface of the substrate was sequentially irradiated with visible light having a wavelength of 400 to 800 nm, and the reflected light from the coated surface was measured to calculate the reflectance (reflected light / irradiated light) at each wavelength. The relationship between the wavelength (nm) and the reflectance (%) of the silver alloy-coated substrate of Example 1 is shown as Example 1A in the graph of FIG.
Next, the silver alloy-coated substrate was left in a high-temperature and high-humidity atmosphere having a humidity of 90% and a temperature of 85 ° C. for 5 hours, and thereafter the reflectance at each wavelength of 400 to 800 nm was calculated in the same manner in a normal atmosphere. The relationship between the wavelength and reflectance of the silver alloy-coated substrate of Example 1 after being left in a high-temperature and high-humidity atmosphere is shown as Example 1B in the graph of FIG.
The changes in reflectance at wavelengths of 700 nm, 550 nm, and 400 nm (values obtained by subtracting the initial reflectance from the reflectance after the test) were −3.02%, −5.1%, and −3.19%, respectively. It was. These results are shown in the graph of FIG.

[Example 2]
Production of sputtering target material under the same conditions as in Example 1 except that the various golds of Ag, Pd, Cu and Ge were weighed so as to be 95.0Ag-3.0Pd-1.0Cu-1.0Ge. And it sputter | spatterred to quartz glass, and formed into a film with a film thickness of 200 nm, and was set as the silver alloy coating substrate of Example 2. FIG. 2B shows an AFM image (approximately 30,000 times) of the thin film on the surface of the silver alloy-coated substrate after annealing the substrate at 250 ° C. for 1 hour in the air. The silver alloy shown in this image had an Ra of 1.244 nm and a PV of 17.99 nm.

Next, the reflectance at each wavelength of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and the relationship between the wavelength and the reflectance was shown as Example 2A in the graph of FIG.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated. The relationship between the wavelength and reflectance of the silver alloy-coated substrate of Example 2 after being left in a high-temperature and high-humidity atmosphere is shown as Example 2B in the graph of FIG.
The increasing rates of reflectance at wavelengths of 700 nm, 550 nm, and 400 nm were −1.03%, −1.32%, and −3.75%, respectively. These results are shown in the graph of FIG.

[Comparative Example 1]
Production of sputtering target material under the same conditions as in Example 1 except that the various golds of Ag, In, Cu and Ge were weighed to be 97.0Ag-1.0In-1.0Cu-1.0Ge. And it sputter | spatterred to quartz glass, and formed into a film with a film thickness of 200 nm, and was set as the silver alloy coating substrate of the comparative example 1. FIG. 2C shows an AFM image (approximately 30,000 times) of the thin film on the substrate surface after annealing this silver alloy-coated substrate in air at 250 ° C. for 1 hour. The Ra of the silver alloy shown in this image was 0.985 nm and PV was 16.15 nm.

Next, the reflectance at each wavelength of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and the relationship between the wavelength and the reflectance was shown as Comparative Example 1A in the graph of FIG.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated. The relationship between the wavelength and the reflectance of the silver alloy-coated substrate of Comparative Example 1 after being left in a high-temperature and high-humidity atmosphere is shown as Comparative Example 1B in the graph of FIG.
The increasing rates of reflectance at wavelengths of 700 nm, 550 nm, and 400 nm were −4.16%, −29.43%, and −17.72%, respectively. These results are shown in the graph of FIG.

[Comparative Example 2]
Production of sputtering target material under the same conditions as in Example 1 except that the various golds of Ag, In, Cu, and Ge were weighed to be 95.0Ag-3.0In-1.0Cu-1.0Ge. And it sputter | spatterred to quartz glass, it formed into a film with a film thickness of 200 nm, and was set as the silver alloy coating substrate of the comparative example 2. FIG. 2D shows an AFM image (about 30,000 times) of the thin film on the surface of the silver alloy-coated substrate after annealing the substrate at 250 ° C. for 1 hour in the air. The silver alloy shown in this image had an Ra of 1.631 nm and a PV of 30.97 nm.

Next, the reflectance at each wavelength of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and the relationship between the wavelength and the reflectance was shown as Comparative Example 2A in the graph of FIG.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated. The relationship between the wavelength and reflectance of the silver alloy-coated substrate of Comparative Example 2 after being left in a high-temperature and high-humidity atmosphere is shown as Comparative Example 2B in the graph of FIG.
The increasing rates of the reflectance at wavelengths of 700 nm, 550 nm and 400 nm were −6.71%, −24.73% and −11.7%, respectively. These results are shown in the graph of FIG.

[Example 3]
Production of sputtering target material and sputtering onto quartz glass under the same conditions as in Example 1 except that the various golds of Ag, Pd, Cu, and Ge were weighed to be 75Ag-10Pd-5.0Cu-10Ge. And a silver alloy coated substrate of Example 3 was formed to a film thickness of 200 nm. After annealing this silver alloy coated substrate in air at 250 ° C. for 1 hour, Ra of the thin film on the surface of the substrate was 1.339 nm and PV was 17.24 nm.

Subsequently, the reflectances at wavelengths of 700 nm, 550 nm and 400 nm of the silver alloy-coated surface of this substrate were calculated in the same manner as in Example 1, and were 90.17%, 87.54% and 77.23%, respectively.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated to be 88.44%, 85.37%, and 75.38% in order.
The reflectance change values at wavelengths of 700 nm, 550 nm, and 400 nm were −1.73%, −2.17%, and −1.85%, respectively.

[Example 4]
Production of sputtering target material under the same conditions as in Example 1 except that the various golds of Ag, Pd, Cu, and Ge were weighed to be 99.7Ag-0.1Pd-0.1Cu-0.1Ge. Then, sputtering onto quartz glass was performed to form a silver alloy-coated substrate of Example 4 having a film thickness of 200 nm. After the silver alloy-coated substrate was annealed in air at 250 ° C. for 1 hour, the thin film on the substrate surface had a Ra of 1.283 nm and a PV of 18.76 nm.

Subsequently, the reflectance at wavelengths of 700 nm, 550 nm and 400 nm of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and they were 96.53%, 95.33% and 92.89%, respectively.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated to be 92.65%, 89.41%, and 8699% in order.
The changes in reflectance at wavelengths of 700 nm, 550 nm, and 400 nm were −3.88%, −5.92%, and −5.90%, respectively.

[Example 5]
Production of sputtering target material under the same conditions as in Example 1 except that the various golds of Ag, Pt, Cu, and Ge were weighed to be 97.0Ag-1.0Pt-1.0Cu-1.0Ge. And it sputter | spatterred to quartz glass, and formed into a film with a film thickness of 200 nm, and was set as the silver alloy coating substrate of Example 5. After the silver alloy-coated substrate was annealed in air at 250 ° C. for 1 hour, the thin film on the substrate surface had a Ra of 1.371 nm and a PV of 15.22 nm.

Subsequently, the reflectances at wavelengths of 700 nm, 550 nm and 400 nm of the silver alloy coated surface of this substrate were calculated in the same manner as in Example 1, and were 94.33%, 91.26% and 81.77% in this order.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated to be 91.14%, 85.84% and 78.54% in order.
The increasing rates of reflectance at wavelengths of 700 nm, 550 nm, and 400 nm were −3.19%, −5.42%, and −3.23%, respectively.

[ Reference Example 1 ]
A thin film having a thickness of 200 nm was formed under the same conditions as in Example 5 except that Pt was replaced with Au to obtain a silver alloy-coated substrate of Reference Example 1 . After the silver alloy-coated substrate was annealed in air at 250 ° C. for 1 hour, the thin film on the substrate surface had a Ra of 1.229 nm and a PV of 16.49 nm.
Subsequently, the reflectance at wavelengths of 700 nm, 550 nm and 400 nm of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and they were 92.44%, 89.16% and 86.47% in this order.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated to be 89.19%, 84.04%, and 83.16%, respectively.
The reflectance change values at wavelengths of 700 nm, 550 nm, and 400 nm were −3.25%, −5.12%, and −3.31%, respectively.

[ Reference Example 2 ]
Production of sputtering target material and sputtering to quartz glass under the same conditions as in Example 1 except that Ag, Pd, and Ge were measured to be 97.5Ag-1.0Pd-1.5Ge. And a silver alloy coated substrate of Reference Example 2 was formed. FIG. 5 shows an AFM image (about 30,000 times) of the thin film on the surface of the silver alloy-coated substrate after annealing the substrate at 250 ° C. for 1 hour in the air. Ra was 5.62 nm and PV was 57.13 nm.
Next, in the same manner as in Example 1, the reflectance (reflected light / irradiated light) at each wavelength of the silver alloy-coated surface of the substrate was calculated. It shows the relationship between the wavelength of the silver alloy coating the substrate of Reference Example 2 (nm) and the reflectance (%) in the graph of FIG. 4 as a reference example 2 A. For example, the reflectances at wavelengths of 700 nm, 550 nm, and 400 nm were 94.04%, 91.55%, and 80.26%, respectively.
Next, the silver alloy-coated substrate is left in the same atmosphere as in Example 1, and then the reflectance at each wavelength is calculated. The relationship between the wavelength (nm) of the silver alloy-coated substrate and the reflectance (%) is shown in FIG. It was shown as Reference Example 2B in the graph. For example, the reflectances at wavelengths of 700 nm, 550 nm, and 400 nm were 91.32%, 89.53%, and 79.89%, respectively.
The change values of the reflectance at wavelengths of 700 nm, 550 nm, and 400 nm were −2.72%, −2.02%, and −2.37%, respectively.

[Comparative Example 3]
A sputtering target material was produced and sputtering was performed on quartz glass under the same conditions as in Example 1 except that the various golds of Ag and Ge were weighed to 98.5 Ag-1.5 Ge, and the film thickness was 200 nm. As a result, a silver alloy-coated substrate of Comparative Example 3 was obtained.
Next, the reflectance at each wavelength of the silver alloy-coated surface of this substrate was calculated in the same manner as in Example 1, and the relationship between the wavelength and the reflectance was shown as Comparative Example 3A in the graph of FIG.
Next, the silver alloy-coated substrate was left in the same atmosphere as in Example 1, and then the reflectance was calculated. The relationship between the wavelength and reflectance of the silver alloy-coated substrate of Comparative Example 3 after being left in a high-temperature and high-humidity atmosphere is shown as Comparative Example 3B in the graph of FIG. For example, the reflectances at wavelengths of 700 nm, 550 nm, and 400 nm were 85.12%, 82.96%, and 77.11%, respectively.
The reflectance change values at wavelengths of 700 nm, 550 nm, and 400 nm were −9.34%, −8.73%, and −6.23%, respectively.

[Consideration of Examples and Comparative Examples]
When Example 1 and Comparative Example 1, which differ only in the type of the second metal, and Example 2 and Comparative Example 2 are respectively compared, the reflectance between silver alloys before processing in a high-temperature and high-humidity atmosphere, that is, immediately after production is compared. Even so, no significant difference was observed, which was 77 to 83% on the low wavelength (400 nm) side and 93 to 96% on the long wavelength side (800 nm) (see FIG. 2).
When the treatment was performed in a high-temperature and high-humidity atmosphere, the reflectances of the silver alloys of Examples 1 and 2 and Comparative Examples 1 and 2 decreased. The decrease in reflectivity was smaller in Examples 1 and 2 than in Comparative Examples 1 and 2 at any wavelength. Particularly, the decrease in reflectivity was 1 to 5% in Examples 1 and 2 near the wavelength of 550 nm. On the other hand, in Comparative Examples 1 and 2, it reached nearly 25 to 30% (see FIG. 3), and a marked difference was observed. The Ag—Pd—Cu—Ge alloy was more Ag-In—Cu—Ge alloy. It was found to have better moisture resistance.

This is also the case where Pd, Cu and Ge are 10% by weight, 5.0% by weight and 10% by weight (Example 3), and even when Pd, Cu and Ge are the lower limit (when Cu is not considered dense) The same tendency was observed when the lower limit of 0.10% by weight (Example 4) was used.
Also the silver alloy thin film of Examples 1 and 2 and Comparative Examples 1 and 2 showing an image in Figure 1, when comparing the respective Ra and P-V, only Ra of Example 1 is smaller than the Ra of the Comparative Example 1 In all other cases, Examples 1 and 2 are smaller and it can be inferred that atomization is achieved. Further, when the silver alloy thin film (FIGS. 1A and 1B) of Examples 1 and 2 (Ag—Cu—Ge—Pd) and the silver alloy thin film (FIG. 5) of Reference Example 2 (Ag—Pd—Ge) were compared, example 1 and clearly reduced the particle size of the second silver alloy thin film, it is Ru divided atomization is achieved by addition of Cu.

1A to 1D are AFM images (about 30,000 times) of the silver alloy thin films after the 250 ° C. annealing treatment of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, in order. It is a graph which shows the relationship between the wavelength (nm) and reflectance (%) of the silver alloy thin film before and after the high temperature, high humidity atmosphere treatment of Example 1, Example 2, Comparative Example 1 and Comparative Example 2. It is a graph which shows the change value of the reflectance in wavelength 700nm, 550nm, and 400nm of the silver alloy thin film before and after the high temperature, high humidity atmosphere process of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. It is a graph which shows the relationship between the wavelength of a silver alloy thin film before and after the high temperature high humidity atmosphere process of the reference example 2 and the comparative example 3, and a reflectance. It is an AFM image (about 30,000 times) of the silver alloy thin film after the 250 ° C. annealing treatment of Example 7.

Claims (2)

Palladium 0.10 to 10 wt%, copper 0.10 to 5.0 wt%, Ri germanium from 0.10 to 10 wt% and the balance silver deposition, decorative silver and having a moisture-resistant alloy. A decorative article characterized in that a decorative silver alloy according to claim 1 is coated on the surface of a decorative substrate.

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