JP2922226B2 - Decorative white gold alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION The present invention relates to a decorative white metal alloy used for processing materials such as rings, necklaces, brooches, tie stoppers, plates and wires used as accessories, and castings. About.

[Conventional technology]

White gold alloy is mainly made of Ni or
Pd has been alloyed and used as a substitute for platinum for a long time. Ni-based alloys are Au-Ni (5 to 25%)-Cu (10 to 25%).
%)-Zn (1-5%), and the Pd-based alloy is Au
The structure range of -Pd (5 to 40%)-Ag (10 to 20%)-Ni (1 to 5%) is general.

[Problems to be solved by the invention]

According to the prior art as described above, Ni-based alloys have high hardness and excellent spring properties, but have a problem that they are unsuitable for chain processing or delicate work due to their excessively high hardness. In addition, there is also a problem that castability is poor due to a large amount of Ni added, and that cavities are easily generated inside the cast body.

On the other hand, Pd-based alloys are often used for chain processing and delicate work because they have good workability, but they may be inconvenient because the hardness of the cast itself is small. For example, when a jewel such as a diamond or ruby is to be stopped on a ring or a necklace, since the strength of the pawl is weak, the holding of the wand is likely to be loose and the jewel may be dropped.

In addition, when working on tie pins, brooches, eyeglass frames, etc., a brazing process will always be required.
In the case of a system alloy, this heating causes softening, and the strength of the brazing portion becomes a problem.

[Means for solving the problem]

In the present invention, Pd is 10 to 35% by weight, Ag is 1 to 10%, Cu
1 to 10%, 0.5 to 10% of Zn, 0.5 to 10% of In, and the balance is 50 to 83.5%. 10-35%, Ag 1-
10%, Cu 1-10%, Zn 0.5-10%, In 0.5-10%,
Further, it is characterized in that it is a decorative white gold alloy containing 0.05 to 2% of one or more of Mn, Fe, and Co and the balance being 50 to 83.5% of Au.

[Action]

According to the above structure, the occluded gas in the molten metal can be reduced by adding a Zn-0.5 to 10 wt% and an In0.5 to 10 wt% to a quaternary alloy of Au-Pd-Ag-Cu as a basic composition. In addition to improving castability, workability can be improved by suppressing the occurrence of internal defects such as pinholes and blowholes in the ingot.

This Au-Pd-Ag-Cu-Zn-In alloy further contains Mn, Fe, Co
By adding at least one of 0.05 to 2 wt%, the composition after casting can be made microcrystalline and the hardness can be increased, and the appropriate strength can be maintained even after a heating step such as brazing.

Here, the reason that Pd is limited to 10 to 35 wt% is that the addition of less than 10 wt% cannot completely remove the golden color of Au, and the addition of more than 35 wt% results in a dark gray color tone. Cannot obtain the desired color tone.

The reason why the lower limit of the addition amount of Ag and Cu was set to 1 wt% is as follows.
This is because if the addition is less than wt%, a synergistic effect with other elements cannot be obtained, and if the addition exceeds 10 wt%, the excellent corrosion resistance of the gold alloy may be deteriorated.

Furthermore, the reason why the contents of Zn and In are each limited to 0.5 to 10 wt% is that if the content is less than 0.5 wt%, the degassing effect is insufficient and the castability cannot be improved. Is remarkably reduced, and the workability is adversely affected. The addition of Zn and In is for obtaining the effect of the synergistic action of both, and the addition of either one cannot obtain the effect intended by the present invention.

In addition, the lower limit of the addition amount of Mn, Fe, and Co as the secondary additive elements is
The reason for setting the content to 0.05 wt% is that if the addition is less than that, the effect of suppressing the growth of crystal grains in the cast body is small and the improvement of the heat resistance cannot be expected. Is also to deteriorate.

〔Example〕

Examples 1 to 16 are shown in the table below, and the workability, the hardness of the cast body, and the castability (fluidity, porosity, casting surface) were compared with those of the conventional example.

The workability was evaluated by melting 500 g of each sample in a Tamman furnace, casting it into a 10 mm thick and 25 mm wide plate,
After annealing at ℃, rolling was performed for comparison.

In the test after casting, the weight of one sample was 10 g, and the fluidity to the precision part, the degree of porosity, and the casting surface on the casting surface were observed by the lost wax casting method using a high frequency suction type precision casting machine. Went and compared. The hardness was measured on the surface of the casting.

[Effects of the Invention] From the test results in the table, it can be seen that Conventional Examples A, C, E, and F have high hardness but are extremely difficult to process, and have poor castability such as fluidity, a cavity, and a casting surface. Further, it can be seen that the conventional examples B, D, and G have extremely good workability but low hardness.

On the other hand, the thing of the present invention has good fluidity to a high-precision part with high hardness, and also has a beautiful casting surface on the surface of the casting.

In addition, there are few defects inside the ingot, the workability is good, and an excellent decorative white gold alloy is obtained.

Continuation of the front page (72) Inventor Takashi Miyamoto 11-17 Kugahoncho, Fushimi-ku, Kyoto-shi, Kyoto-shi Kyocera Corporation Kyoto Fushimi Works (58) Field surveyed (Int.Cl. ⁶ , DB name) C22C 5/02

Claims (2)

(57) [Claims] (1) Pd by weight: 10 to 35%, Ag: 1 to 10%, Cu
1 to 10%, 0.5 to 10% of Zn, 0.5 to 10% of In, the balance being 50 to 83.5% of Au. 2. Pd content of 10 to 35%, Ag content of 1 to 10%, Cu
1 to 10%, Zn 0.5 to 10%, In 0.5 to 10%, and M
Contains 0.05 to 2% of at least one of n, Fe, and Co, with the balance being 50 to 8
Decorative white gold alloy consisting of 3.5% Au.