JP6614791B2 - Pd alloy for jewelry - Google Patents

Description

  The present invention relates to a Pd alloy used for jewelry.

  Pt is preferred as a white noble metal for rings, necklaces, pendants, earrings, etc., but Pt is a very expensive noble metal, so a Pd alloy is used as an alternative noble metal for jewelry.

  As for this Pd alloy for jewelry, Pd950 and Pd500 are stipulated in the “Provision of Labeling of Materials for Jewelry and Precious Metal Products 2012 Revised Edition” (Jewelry Association of Japan), but there is no provision for additive metals, Au, Ag, Cu, etc. are generally used as additive metals.

  In jewelry, since high-quality alloys are preferred, alloys (Pd950) containing 95% Pd in mass ratio are generally sold (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). ).

JP2010-261096 JP2012-527529 JP 2014-176635 A

  However, these Pd950 alloys are often used after being subjected to white metal plating such as Rh because there is a problem with the black color tone peculiar to Pd. However, when it is used after being plated in this way, there is a problem that if the plating is peeled off during use, the original color tone of the alloy is exposed, and the problem of aesthetics is pointed out by the user.

  Further, Pd alloys have a problem that it is difficult to obtain a bright white color with respect to color difference and brightness.

  Furthermore, since this Pd alloy has a hardness of Hv100 or less, deformation during use is regarded as a problem.

  Therefore, there is a demand for a Pd alloy material that is bright white, has high hardness, is excellent in workability, and is relatively inexpensive.

  An object of the present invention is to solve such a problem.

Therefore, the present invention uses a Pd950 alloy in which Ru is 2.5 to 4.5 mass%, Ag is 0.5 to 2.5 mass%, and the remainder is Pd.

Further, a Pd950 alloy having Ru 3.0 to 4.5 mass%, Ag 0.5 to 1.5 mass%, Cu 0.5 to 1.0 mass%, and the remainder being Pd is used.

  Here, the purpose of adding Ru is that it can be expected to have an effect on the hardness due to the refinement of Pd crystal, and also has an effect on the silver-white color tone of Ru. If it is less than 5 mass%, there is no effect of addition. On the other hand, if the addition amount is large, the amount of gas generated increases during high-frequency dissolution under reduced pressure, and 5.0 mass% is the limit. In addition, a good casting effect was obtained when the amount added was 3.0 mass% with little generation of gas.

  Moreover, the purpose of adding Ag is because Ag is expected to have an effect on whitening with a small amount of addition, focusing on the fact that Ag has a high reflectance among metals. It turned out that it works brightly.

  When the addition amount was less than 0.5 mass%, there was no effect of addition, and a remarkable effect was obtained at 3.0 mass%.

  Further, the purpose of adding Cu is considered to affect the hardness, but the castability is greatly improved, and the addition contributes to the melting point drop and the castability.

  When the addition amount was less than 0.5 mass%, there was no effect of addition, and when it exceeded 3.0 mass%, there was a difficulty in dissolution.

  The purpose of adding Pt is to expect the effect on the hardness by the refinement of the crystal and the effect of mechanical properties such as malleability and ductility. This is to contribute to the improvement of processing characteristics of thin and delicate parts of jewelry products.

  If the addition amount is less than 0.5 mass%, there is no effect of addition, and if it exceeds 3.0 mass%, the product price is affected.

  In the present invention as described above, the hardness and color tone were remarkably improved by adding Ru and Ag to the Pd alloy for jewelry.

  Moreover, improvement of workability and castability was obtained by adding Cu or Pt.

  Examples of the present invention are shown in Table 1.

  In each example, a test piece (thickness 1 × width 10 × length 20, unit mm) was prepared from a Pd alloy by a predetermined method. In addition, since the surface state was covered with the oxide film etc., the test piece grind | polished with the water-resistant abrasive paper was used for the test piece after casting.

  Table 1 shows the composition list of each example and the hardness, color difference and castability after precipitation hardening.

  The hardness of the test piece was measured at HV0.2 with a Vickers hardness tester after the sample surface was polished and smoothed.

  The color difference was measured with a color difference meter. ΔE was calculated from lightness (L value) saturation.

  The castability was judged to be poor if the corners and edges of the test piece had poor casting, and those having 10 or more cast holes.

表１に示す結果より、比較例に比べてＲｕの添加により、硬さの向上を確認することができた。

From the results shown in Table 1, it was confirmed that the hardness was improved by adding Ru as compared with the comparative example.

  Furthermore, it can be confirmed that the color tone is improved by addition of Ag, and addition of Ru is considered to be effective in improving the color tone.

  In addition to the above examples, Ru-Ag-Pt and various Pd950 alloys with Pd as the rest could be tested, but the price would increase if the additive material was only Ag-Pt. It was removed from the examples.

Claims (2)

Pd950 alloy for jewelry with Ru 2.5 to 4.5 mass%, Ag 0.5 to 2.5 mass%, and the remainder Pd. A Pd950 alloy for jewelery in which Ru 3.0 to 4.5 mass%, Ag 0.5 to 1.5 mass%, Cu 0.5 to 1.0 mass%, and the remainder as Pd.