JPS61106736A - Ornamental hard platinum alloy - Google Patents

Abstract

PURPOSE:To obtain the ornamental hard platinum alloy having superior workability and showing relatively high hardness, by preparing the platinum alloy from specific percentage of platinum, iron, and copper. CONSTITUTION:The platinum alloy consisting of, by weight, 85-90% platinum, 3.5-5.5% iron, and the balance >=5% copper is manufactured. This alloy can be cold-worked in the state of a solid soln. formed by soln. heat treatment, and it can give a hardness of about Hv280-335 by aging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a platinum alloy used for ornaments such as rings, necklaces, tie pins, hour hand sides, eyeglass frames, and earrings.

[Background of the invention and drawbacks of the prior art]

Platinum-palladium alloys are widely used as decorative platinum alloys. Although this alloy has excellent workability, its mechanical strength is relatively low. Therefore, rings, watch parts, eyeglass frames, etc. are easily scratched while being carried, and are easily deformed, so they are thin. The design is difficult and prevents weight reduction.

On the other hand, platinum alloys aimed at achieving the same hardness include platinum iridium alloys, platinum cobalt alloys (for example, JP-A-55
-85645), but the former has a high melting point and has poor workability in melting and casting, while the latter has poor cold plastic workability.

[Purpose and structure of the invention]

Therefore, the purpose of the present invention is to develop a platinum alloy that is excellent in workability such as melting and casting and processing, and exhibits relatively high hardness.
The target alloy was 0% (by weight, the same applies hereinafter), and iron and copper were added to it to impart age hardenability.

Hereinafter, a detailed explanation will be given based on examples.

[Embodiments of the invention]

85-90% platinum ()'t), iron (Fe), copper (
An alloy containing Cu) and others was subjected to high-frequency melt casting in an albo/gas atmosphere, and the resulting ingot was cold rolled to obtain a plate-shaped test piece. Some alloys cannot be cold rolled, so test pieces were cut from ingots. ``These test pieces were solution-treated by rapidly cooling them from a temperature of 1000°C, and further subjected to aging treatment at a temperature of 400° to 800°C, and changes in hardness were measured.

The target composition, hardness in solution state (Vickers hardness Hv), maximum hardness achieved by aging treatment, and evaluation of cold workability for these alloys (llI&L1-25) are shown in Table +11 and Table (2). Shown below.

As a result of chemical analysis of some of the alloys, the deviation of the alloy composition from the target composition was within 0.5%.

The 85% Pt alloy will be explained with reference to Table (1).

As seen in Comparative Example (% 15), no age hardening was observed in the known 15% Pd alloy;
Its hardness is 8 regardless of whether it is in the solution state or aged state)
(V is around 90.

In contrast, alloys containing 3.5 to 5.5% Fe and the balance being Cu (Rounds 1 to 4), and a portion of Cu containing a total of 4% or less In the alloys (-5 to 9) substituted with C01Ni, Pd, Au, and Ag, the Hv
A hardness of 295 to 410 is obtained and cold working is possible in the solution state.

On the other hand, alloys containing 3% or less Fe (fklo) do not have sufficient hardness, and alloys containing 6% or more Fe (rkl 1) and alloys containing 5% or more Co (tooth 12.13), cold working is not possible.

An alloy containing 5% Fe and the balance being Ni (rI&
In 1L14), although the hardness in the solution state is high, the hardness obtained by aging treatment is not so high.

Next, the 90% Pt alloy will be explained with reference to Table (2).

Comparison? As shown in J (11 & 125), no age hardening is observed in alloys containing no Fe but 5% Cu and 5% Pd.

On the other hand, it contains 4 to 5.5% Fe, and the balance is C.
Alloy consisting of u (-16,17) and part of Cu
In alloys (%18-21) consisting of Cu with substitutions of d, Ni, Co, Ir, and Rh, with the balance being 4% or more, hardness of Hv280-335 can be obtained by aging treatment, and in the solution state can be cold worked.

On the other hand, in the alloy (r&23) with an Fe content of 3% or less, age hardening is not sufficient, and the Fe content is 6%.
Cold working is not possible with the above alloys (LV&122) or alloys with a Cu content of 3% or less (L24).

The present invention targets noble metal Pt alloys, that is, alloys containing 85% or more of Pt, but the pt content is 90%.
If it exceeds this, the desired hard alloy cannot be obtained. On the other hand, F
When the content of e is less than 3%, age hardening is insufficient, and 6
% or more, cold working becomes difficult. In addition, from the viewpoint of cold workability, a Cu content of 5% or more is required in a Pt-Fe-CuB base alloy, and a Cu content of 4% or more is required when a part of Cu is replaced with another element. is necessary.

The addition of Co%Ni and Ir%Rh contributes to improving the hardness,
Addition of Pd, Au%Ag improves cold workability. These effects are produced depending on the amount added even when added at 0.1%, but if the total amount added exceeds 4%, cold working becomes difficult or age hardening becomes insufficient.

[Effects of the Invention] As described above, the alloy of the present invention can be cold-worked in a solution-treated state, and high hardness can be obtained through aging treatment, so it is effective when used in the above-mentioned ornaments.

Claims (2)

[Claims] (1) 85-90% platinum (weight%, same below), iron 3.
A decorative hard platinum alloy consisting of 5 to 5.5% copper and the balance 5% or more. (2) 85 to 90% platinum, 3.5 to 5.5% iron, and at least one element selected from cobalt, nickel, palladium, rhodium, iridium, gold, and silver, with a total of 0
．． A decorative hard platinum alloy consisting of 1 to 4% copper and the balance 4% or more.