JPH066766B2 - Gold alloy - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of 18-karat gold, so-called white gold, which has a color tone similar to that of a platinum alloy, and more particularly to the provision of a gold alloy used for decoration.

[Prior Art] Platinum generally has a neat sparkle and a high-class feeling compared to gold ornaments and the like, and is widely used for jewelry.

However, despite the small amount of platinum produced, its excellent physical properties, mechanical properties and chemical properties make it a versatile demand for physicochemical instruments, dental materials, electronic industrial materials, etc. It is expensive because it has, and the supply amount was naturally limited.

Therefore, gold 75 wt%, silver 8 wt%, palladium 10 wt%
And white carat gold obtained by dissolving 7% by weight of any one of Cu, Zn, and Ni was used as a substitute for platinum.

Also, 75 wt% gold, 3.5 wt% copper, and either Zn or Ni
White carat gold obtained by dissolving 21.5% by weight was used as a substitute for platinum.

[Problems to be Solved by the Invention] However, such a conventional 18-carat white gold material is changed to a platinum material, for example, a platinum alloy having a chemical composition of 85% by weight of platinum, 8% by weight of palladium, and 7% by weight of copper. In comparison, the color tone is reddish, and it does not exhibit a white color with the texture peculiar to the above-mentioned platinum alloy. For this reason, it is generally plated with rhodium to complement its color.

Many of the conventional products were found to have the drawback of discoloration due to peeling of the rhodium plating.

In addition, conventional 18-carat white gold materials include processed materials (others such as weather resistance, brown color, hardness, corrosion resistance et
In terms of c), because of the difficulty of heat treatment for precipitation hardening characteristics,
It was not always satisfactory as a decorative material.

The gold alloy according to the present invention is an alternative to the conventional 18-carat white gold material, and has a color tone close to that of pure platinum material, as well as heat treatment and workability similar to that of yellow gold.・ The purpose is to provide gold.

[Example] Hereinafter, a typical example of the gold alloy according to the present invention will be specifically described.

First, 75 wt% gold with 99.99% quality and 8-12 palladium
% By weight, 7-5% by weight silver, 5-4% by weight nickel
And 5 to 4% by weight of copper were melted and cast to obtain a white gold cast product.

Also, 75% by weight of 99.99% gold, 8-12% by weight of palladium, 7-5% by weight of silver, 5-4% by weight of nickel, and 5-4% by weight of cobalt are melted and cast into white.・ I got a gold cast item.

The palladium-nickel-copper alloy is preferably added as a mother alloy.

The white gold cast product thus obtained is treated in a nitrogen or argon gas atmosphere at 800 to 900 ° C. and then cooled with water.

In the heat treatment of this white gold cast product
In a low temperature range of 600 ° C. or lower, aging or intermetallic compounds are exfoliated, which causes hardening of cast products. Therefore, it is preferable to perform heat treatment in a temperature range as high as possible.

The 18-carat white gold cast thus obtained was identical in color to the textured blackish white of pure platinum.

Further, since Hv was 180, tensile strength was 43, and elongation was 27, the cold workability such as cold forging and cold forging was good, and particularly the drawing property was good.

In this workability, the above values were obtained when the composition of Ni-Cu and Ni-Co was 1: 1, and when the ratio was other than this, the hardness increased and the workability decreased.

Then, cast the obtained white gold product for 20
It was confirmed that the surface of the cast product was closer to white than the color tone of the pure platinum material when it was treated with a hydrochloric acid solution having a concentration of%.

Example 1 Gold 75 wt%, Palladium 10 wt%, Silver 6 wt%, Nickel
A gold alloy having a chemical composition of 4.5% by weight and 4.5% by weight of copper was obtained.

The gold alloy obtained here had a white color tone close to that of a pure platinum material, and had the same cold workability as 18K yellow.

Example 2 A gold alloy was obtained under the same conditions as in Example 1 except that copper was replaced by 4.5% by weight of cobalt.

The color tone of the gold alloy obtained here was the same as that of the gold alloy obtained in Example 1, and the workability was even better.

Example 3 A gold alloy having a chemical composition of 75 wt% gold, 8 wt% palladium, 7 wt% silver, 5 wt% nickel, and 5 wt% copper was obtained.

The gold alloy obtained here had a slightly reddish color tone as compared with the gold alloy obtained in Example 1 and showed a tendency to be inferior in comparison with the platinum material. It was able to be sufficiently used for practical use.

Example 4 A gold alloy having a chemical composition of 75 wt% gold, 12 wt% palladium, 5 wt% silver, 4 wt% nickel, and 4 wt% copper was obtained.

The gold alloy obtained here had the color tone closest to that of platinum material, and had the same workability as 18K yellow, but had the drawback of high material cost. .

Comparative Example 1 A gold alloy having a chemical composition of 75 wt% gold, 7 wt% palladium, 8 wt% silver, 5 wt% nickel, and 5 wt% copper was obtained.

The gold alloy obtained here had a reddish-purple color tone, which was different from the black-white color tone of pure platinum materials, and could not be used as a substitute for platinum materials.

[Effect] The gold alloy according to the present invention has a so-called 18-carat white gold color tone closer to that of pure platinum material as compared with the conventional white gold.

As a result, it has become possible to provide, at a low price, neat and luxurious decorations as an alternative to expensive platinum decorations.

In addition, it is possible to provide ornaments that are less likely to be scratched and have no deformation compared to pure platinum materials.

Furthermore, it is possible to provide a decorative material that is relatively hard and is easily scratched, and has better workability than the platinum alloy of Pt-Pd-Cu.

Claims (1)

[Claims] 1. A gold alloy comprising 75% by weight of gold, 8 to 12% by weight of palladium, 7 to 5% by weight of silver, 5 to 4% by weight of nickel, and 5 to 4% by weight of copper or cobalt.