JPH03130335A - White gold alloy for ornament - Google Patents

Abstract

PURPOSE:To manufacture the white gold alloy for ornament improved in castability and having good workability by adding specified amounts of Zn, In, W and Mo to a gold alloy contg. specified ratios of Pd, Ag and Cu. CONSTITUTION:By weight, 0.5 to 10% Zn and 0.5 to 10% In and, furthermore, 0.05 to 1% of one or 2 kinds of W and Mo are added to an alloy essentially consisting of Au and contg. 10 to 35% Pd, 1 to 10% Ag and 1 to 10% Cu. In this way, the white gold alloy for ornament of 12 to 20K (50 to 83.5%) by which the casting skin on the surface of a cast body is made beautiful and having less defects on the inside of an ingot as well as having good workability can be obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a decorative white gold alloy used in processed materials such as plates and wires used as rings, necklaces, brooches, tie holders, and other accessories, or in cast bodies. Regarding.

[Conventional technology]

White gold alloys are mainly alloyed with Ni and Pd and have been used as a substitute for platinum for a long time in order to bleach the golden color of gold.
(10 to 25
(10-20χ)-Ni(1-5χ) is common.

[Problem to be solved by the invention]

According to the above-mentioned conventional technology, Ni-based alloys have a high hardness and excellent spring properties, but on the other hand, their excessive hardness makes them unsuitable for chain processing or delicate craftwork. Further, due to the large amount of Ni added, castability is poor, and there is also the problem that cavities are likely to occur inside the cast body.

On the other hand, Pd-based alloys have good workability and are often used for chain processing and delicate craftwork, but they are sometimes inconvenient because the hardness of the cast body itself is low. For example, when securing a jewel such as a diamond or ruby to a ring or necklace, the strength of the retaining claw is weak, so the grip on the cane tends to loosen and the jewel may fall off.

In addition, when crafting items such as tie pins, brooches, and eyeglass frames, brazing must go through a process, but Pd
In the case of alloys, this heating causes softening, and the strength of the brazing parts becomes an issue.

[Means to solve problems]

The present invention has Au as the main component, and Pd1O to 35% by weight.
In the alloy containing X, Agl~10X, Cul~IOX, ZnO, 5~10X and In0.5~
10χ and one or two of h and MO in a weight ratio of 0.
05-1χ added and 12-K20 (50-83.5
wt%) white gold alloy.

[Function] According to the above configuration, Au-Pd-Ag-Cu-Zn-
By adding one or both of - and Mo to a six-element alloy of In at a weight ratio of 0.05 to 2χ, the occluded gas in the molten metal is reduced and castability is improved, and the structure after casting is made into microcrystals. It is possible to increase hardness by hardening and maintain appropriate strength even after heating processes such as brazing.

Here, the reason why Pd is limited to 10-35w LX is as follows.
If less than 10 wtχ is added, the golden color of Au cannot be completely decolorized, and if more than 35i+tχ is added, the color tone becomes dark gray and the color tone desired by the present invention cannot be obtained.

Furthermore, the reason why the lower limit addition amount of Ag and Cu was set at 1wt't is that if each is added less than 1wt%, a synergistic effect with other elements cannot be obtained, and if each is added in excess of 10i1t This is because there is a risk of degrading the sex.

Furthermore, the content of Zn and In is 0.5 to 10wt each!
The reason why it is limited to 0.5wtχ is that the degassing effect is insufficient and improvement in castability cannot be expected if it is less than 0.5wtχ.
Addition of more than 0 wtX will significantly lower the melting point, and will also have an adverse effect on processability. In addition, Zn and I
The purpose of adding n is to obtain an effect due to the synergistic action of both, and the intended effect of the present invention cannot be obtained by adding either one.

Furthermore, the lower limit of the amount of W and Mo added is 0.05wt! This is because if the addition amount is less than 1wt'', the effect of suppressing grain growth in the cast body is small and no improvement in heat resistance strength can be expected.
This is because adding more than A significantly reduces workability and also deteriorates castability.

〔Example〕

Examples 1 to 8 are shown in the table below, and compared with conventional examples in terms of workability, hardness of cast bodies, and castability (fluidity, porosity, and cast surface).

For the evaluation of workability, each sample weighing 500 g was melted in a Tamman furnace, cast into a plate shape with a thickness of 1 Q mm and a width of 25 mm, which was annealed at 750°C and then rolled. did.

In the post-casting test, the weight of one sample was set to Log, and a high-frequency suction type precision casting machine was used to observe the fluidity of the precision part, the degree of occurrence of casting cavities, and the casting surface on the surface of the cast body using the lost wax casting method. I went and compared. In addition, hardness was measured on the surface of the cast body.

〔Effect of the invention〕

From the test results in the table, it can be seen that conventional examples A, C, E, and I have high hardness, but are very difficult to process and have poor casting properties such as fluidity, cavities, and casting surface. Furthermore, it can be seen that conventional examples No. 2 and No. 3 have extremely good workability but low hardness.

On the other hand, the material of the present invention has high hardness, good flowability to precision parts, and beautiful casting surface.

Furthermore, the ingot has few internal defects and has good workability, making it an excellent decorative white gold alloy.

Claims (1)

[Claims] 1. Main component is Au, 10 to 35% Pd by weight, A
An alloy containing 1 to 10% of g and 1 to 10% of Cu, 0.5 to 10% of Zn and 0.5 to 10% of In by weight ratio, and 0.05 to 1% of one or both of W and Mo by weight ratio.
K12 to K20 (50 to 83
．． 5wt%) decorative white gold alloy.