JPH0243333A - Platinum alloy for ornament - Google Patents

Abstract

PURPOSE:To improve hardness and flowability to precision parts by adding small amounts of Re and one or more elements among Ru, Rh and Ir to a Pt-Pd alloy with a specific composition. CONSTITUTION:A platinum alloy for ornament is constituted so that it has a composition constituting of, by weight, 80-98% Pt, 1-19% Pd, 0.5-10% Re, and further 0.05-3% of one or more elements among Ru, Rh and Ir. By the addition of Re to the Pt-Pd alloy, the effects of inhibiting the occlusion of gas in molten metal, refining the structure after casting, and increasing mechani cal strength can be obtained. Further, attractive white color can be maintained without deteriorating the color tone of the Pt-Pd alloy. Moreover, by the addi tion of Ru, Rh and Ir, the effects of Re addition are increased and machinability is improved. This platinum alloy is used for ornaments, such as necklace, brace let, tiepin, ring, and earrings.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to necklaces, bracelets, tie pins,
This invention relates to platinum alloys used for ornaments such as rings and earrings.

[Prior Art] Conventionally, binary alloys containing 1 to 20% of Pd have been most commonly used as decorative platinum alloys.

[Problems to be Solved by the Invention] Although this binary alloy has excellent plastic deformability and castability, it has low hardness and mechanical strength, and poor machinability, resulting in the following disadvantages.

In other words, when used for rings and necklaces, there is a problem that they are easily scratched and deformed.Additionally, when using processing methods that require high machinability, such as diamond cutting, a sticky phenomenon occurs, making it difficult to cut surfaces with good reflective properties. There is a problem that I cannot get it.

Furthermore, with regard to jewelry worn with jewelry called stoneware, the strength of the claws that hold the jewelry is weak, which may lead to an accident in which the jewelry falls off.

In most cases, jewelry such as rings, tie pins, and brooches go through a brazing process, but the heating during this process causes the material to soften, making the strength of the parts particularly problematic.

Therefore, in order to improve the hardness of the Pt-Pd alloy, it is known to add about 2 to 5% Cu to make a ternary alloy, but this alloy has the problem of a blackish tone. be.

[Means for solving the problem] The present invention provides Pt 80 to 98 wt%, Pd 1 to 19 wt%
0.5 to 10 wt% of Re was added to the
, Rh, and 1r in an amount of 0.05 to 3 wL%.

The addition of Re to the Pt-Pd alloy has the effect of suppressing gas occlusion in the molten metal, refining the structure after casting, and increasing mechanical strength.
A beautiful white color can be maintained without damaging the color tone of the alloy.

Further, when one or more of RuXRh and Ir is added to the above alloy, the effect of adding Re to the Pt-Pd alloy can be promoted and the machinability can be significantly improved.

Here, the reason why the amount of Re added is limited to 0.5 to 10 wt% is that adding less than 0.5 wt% of Re is insufficient to improve hardness and mechanical strength. , 10
This is because if it exceeds wt%, the melting point becomes too high, making melting and casting difficult.

On the other hand, the amount of one or more of Ru, Rh, and Ir added is 3wt%.
This is because, if it exceeds this, the oxidation of the surface of the cast body becomes severe and, in addition, cavities are likely to occur inside the cast body.

Moreover, if it is less than 0.05 wt%, a synergistic addition effect with Re cannot be expected.

〔Example〕

Pt47.5g, Pd1.5g, Re0.25g, R
U0.25g, Rh0.25g, Ir0.25g were cast using a high-frequency suction precision casting machine using the lost wax casting method.
P t 95. cast into a dendritic shape and shown in the table. Ow
tχ, P d 3. Ow t%, Re 0.5w
t%, Ruo, 5 wtχ, Rh 0.5 wt%,
A containing 0.5 wt% Ir was obtained.

Next, P t49g,, P do, 675 g, R
e0.25g.

Ru0.025g, Rh0.025g, Ir0.0
25g was cast into a dendritic shape using a high-frequency suction precision casting machine using the lost wax casting method to obtain the pt9 B shown in the table.
, Owt%, Pd1.35wt%, Re0.5wt
χ, Ru 0.05 w t%, Rh 0.05 w t
%, Ir0.05wt% B was obtained.

Hereinafter, L was obtained from C in the same manner.

The hardness of this dendritic cast body, the flowability to precision parts, the degree of occurrence of blowholes, and the casting surface of the cast body were observed and compared with alloys A to II made by the prior art.

The table above shows the components, Vickers hardness, and castability of A to L of this example and conventional base metals A to II.

As shown in this table, the hardness of the 95% Pt-Pd binary alloy is 65, whereas the hardness of this example is 102 to 110, which is also 90%.
While the hardness of the Pt-Pd binary alloy is 70, this example has a hardness of 13.
5-142, similarly hardness of 85% ptPd binary alloy 90
On the other hand, in this example, the hardness was 161 to 180, which shows that the hardness was significantly improved.

Moreover, when comparing the castability, the cast body surface (casting surface) of this example is beautiful and there are fewer blowholes.

Furthermore, it has good flowability into precision parts and exhibits excellent castability.

〔Effect of the invention〕

According to the present invention described in detail above, by adding Re to the Pt-Pd alloy and further adding one or more of Ru, Rh, and Ir, the hardness is significantly improved and the fluidity of precision parts is improved. becomes much better.

It also has the effect of suppressing gas occlusion in the molten metal, making the structure after casting finer, increasing mechanical strength, and creating a beautiful casting surface with fewer cavities.

Claims (1)

[Claims] 1. Re in Pt80-98wt%, Pd1-19wt%
0.5 to 10 wt%, and further Ru, Rh, Ir
A decorative platinum alloy characterized by adding 0.05 to 3 wt% of one or more of the above.