JPS609844A - Ag-pd-au type noble metallic alloy material for personal ornament - Google Patents

Abstract

PURPOSE:To obtain a white and brilliant noble metallic alloy for personal ornaments with superior machinability, rollability, sweat resistance and sulfurization resistance by adding a specified amount of Au to a Pd-Ag alloy. CONSTITUTION:This white and brilliant noble metallic alloy for personal ornaments consists of 20-70wt% Pd, 0.1-20wt% Au and the balance Ag. Since Pt is not used, the alloy is obtd. at a low cost and has superior machinability and formability. The alloy shows superior sweat resistance and sulfurization resistance, so it is suitable for use as a material for a watchcase, a watchband, spectacle frames, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a white glittering precious metal alloy material used for accessories such as watch cases, watch bands, and eyeglass frames.

(b) Background and summary of the invention Silver, palladium, platinum, or their alloys are known as white precious metals, but compared to other white bright precious metals, silver is cheaper but has poor sweat resistance. Platinum, on the other hand, is sweat-resistant but has the disadvantage of being too expensive.

However, silver alloys containing 20% by weight or more of palladium are not only sweat resistant but also expensive, such as Ag (80% by weight).
-Pd (20% by weight) alloy is only about three times the price of silver, and about one-eighteenth of the price of platinum. As mentioned above, the lower limit of the palladium content in this case is 20% by weight, but in the case of silver-palladium alloys, they dissolve in solid solution over the entire composition range, so there is no particular -L limit, but The content is preferably 70% by weight in view of white metal photosensitivity, curability and 9-value.

Ag-Pd has sweat resistance and is relatively inexpensive.
When Au is added in an amount of 0.1 to 20% by weight, (a
) improved machinability, (b) improved rolling workability, C) good polishing and puff surface gloss, and (d) excellent cold working, engraving, and forging properties.
and (e) It was found that the itching caused by the polished and puffed surface on the skin was also reduced.

Ag-Pd (20-70% by weight)-A u
(0.1 to 20% by weight) alloy is very suitable as a noble metal alloy material for jewelry of the type mentioned above, and it is the object of the present invention to provide this as an alloy material for jewelry.

Hereinafter, this invention will be explained in detail by way of examples.

(C) Example i) A molten alloy of Ag-Pd (55% by weight) and Au (5% by weight) was cast and rolled to a width of 4.0m+n and a thickness of 3mm.
This was made into a board, punched out, and formed into a watch case. Formability is extremely good, and compared to the 11 times required to form a gold alloy into a watch case of the same shape, the number of forgings required for the alloy material of the present invention was 8 times.

The hardness (Vickers hardness) of this alloy until final forming is:
By the way, it was as follows.

" - Mixed metal plate - 119; Side surface after punching - 189; Side surface annealed after punching (15 minutes at 800° C. in Hz atmosphere) - 110; Back surface after one forging - 189; Back surface annealed after one forging - 115; After final molding -145 In this molding, a fine pattern with a forging punch height of 0.14 mm was attached, and the molding was also very clear.

Next, the final molded clock case was cut. It was found that the machinability was very good and was superior to gold alloys and nickel silver. When this was further polished, the final appearance was extremely beautiful.

The resulting final product was subjected to an artificial sweat test (half immersed in artificial sweat and left at 40'O for 140 hours), but no discoloration occurred. We also tested the sulfurization resistance of the final product by contacting it with a rubber band (strongly contacting it with a rubber band and leaving it for 30 days).
When I did this, there was no change at all.

ii) An alloy of Ag-Pd (55% by weight)-Au (5% by weight) was melted, cast, and wire-drawn to form a 3m+nφ round wire (annealed material: Vickers hardness 110), and a bracelet was prototyped using this. The moldability of the bracelet pieces was good, and the brazing performance of each piece using white wax was extremely good during the work.

After the final polishing, the bracelet was beautiful and had the white glow characteristic of platinum precious metals.

The obtained Braceley/l' was subjected to an artificial sweat test (half immersion, 4
0'C! When I left it for 140 hours, the beauty did not change at all, and after trying it on for about 6 months, I found that
The aesthetic appearance was not compromised, and the skin itching that often occurs when sweating occurs when wearing high nickel alloy or stainless steel watch bands and bracelets did not occur at all.

(D) Effects of the Invention As is clear from 1-1, the precious metal alloy material according to the present invention has excellent cutting and formability, has a smooth polishing puff surface and does not cause itching to the skin, and is reasonably priced. In addition, it has excellent sweat resistance and sulfurization resistance, and does not lose its white light properties, so it is particularly useful as a precious metal alloy material for jewelry such as watch cases, watch bands, and eyeglass frames.

Claims (1)

[Claims] An Ag-Pd-Au precious metal alloy material for jewelry, consisting of 20 to 70% by weight of Pd, 0.1 to 20% by weight of Au, and the balance being Ag.