JPH0913132A - Gold alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide gold alloy which is lightweight, high in hardness, and fresh in color.

SOLUTION: Gold alloy which contains 8-22 karat pure gold, and other composition such as silver, copper and zinc as ternary or quaternary alloy at various ratio, and is useful for manufacturing decorations, coins and gold bars is provided. The gold alloy further contains titanium. Hardness of the alloy can be further increased by the aging heat treatment.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is 8 carats to 22 carats.
Jewelery, coins, characterized by having a carat pure gold content, containing other components such as silver, copper, zinc in various proportions, and also titanium, which is the object of the invention , And gold alloys useful in making gold bars.

[0002]

2. Description of the Related Art Pure gold is extremely soft, and in order to manufacture jewelry, it is necessary to use a material that has characteristics of hardness and wear resistance, and at the same time has warmth and vivid color. Is well known. The hardness of an alloy is due to the phenomenon of precipitation in the solid phase and the phenomenon of disorder-order transition that occurs under a specific temperature and a specific atomic ratio between alloy components. From this point titanium is added to the composition, which imparts new properties to the alloy due to the fact that it contributes to the phenomenon of precipitation mentioned above.

Gold alloys generally consist of the Au-Ag-Cu ternary system and are commercially available in various pure gold contents from 8 carats to 24 carats. Intermediate pure gold content on the market is 9, 10, 12, 14, 18, 2
0, 21 and 22 carats. Until recently, the metals that have been used for centuries in the gold sector for decoration were limited to alloys that were easy to process and had a pleasing color, especially because of their special color and resistance to dirt.
Given the rising price of gold, often over $ 800 per ounce, it is clear that the need for lighter yet equally durable jewelery has emerged.

Furthermore, for more ornate ornaments, in particular a (hollow) bracelet or an annular and ultimately very thin chain similar to the product described in the Italian patent application VI95A000085 by the applicant, for example. There is a need for lighter and more durable products for earrings for economic as well as aesthetic reasons. Due to such requirements, other metals in a pure state have been added to the above three elements for the purpose of producing a decorative alloy.

The most used metal for forming a general quaternary alloy is zinc, which is used as a deoxidizing agent in a small amount such as 0.5% or less, or for adjusting the color of the alloy, workability and mechanical properties. In order to improve the characteristics, a large amount such as 10% or more is added. The combination of gold, silver, copper, and zinc constitutes essentially all the gold alloys commonly used for jewelry. These alloys differ from each other in that small amounts of other metals such as nickel, cobalt, iron, silicon, boron, ruthenium, iridium, and indium are added to the four basic elements. By way of example, the following patents describe the above summary and disclose the various components used to form the gold alloys.

US Pat. No. 2,141,157 (Peterso
n). It contains 33% to 84% gold, 10% to 67% copper, 2% to 10% zinc, 2% to 10% silver, and 0.1% to 5% cobalt. In this alloy, cobalt is used to obtain reversible hardening.

US Pat. No. 2,229,463 (Leac
h). This is 35% to 75% gold, 5% to 25% silver,
It contains 12% to 35% copper, 0.1% to 12% zinc, and 1% to 5% iron. In this alloy, iron is used to obtain both reversible and irreversible hardening.

US Pat. No. 2,248,100 (Loebic
h). This is 33% to 66% gold, 1% to 30% silver,
It contains 10% to 55% copper, 0.5% to 15% zinc, and 0.1% to 5% iron.

US Pat. No. 3,981,723. It describes a white gold alloy containing palladium, silver, indium, and 0.005% iridium or ruthenium.

More recent patents describing alloys of this type include, for example, US Pat. No. 5,180,551 (Leach).
And Garner) and US Pat. No. 5,173,132.
(Solomon). In these patents different combinations of cobalt and nickel are used for the purpose of improving the grain structure, optimizing the color and improving the mechanical resistance.

From the aforementioned patents relating to the state of the art in the field of jewelery, it is clear that titanium does not exist. For processing alloys containing this element, air, oxygen, which is generally present in forming a protective atmosphere during solution treatment, aging, cold working, fusing, etc. This is because special precautions are required due to the active reaction with nitrogen and carbon at high temperature.

The only gold alloy presently known containing titanium is the alloy known as "Gold 990". This alloy has a high carat value, which is 1
The result of research done in the 970's is that it cures two types of challenges: alloys with a very low content of alloying components, while at the same time being aesthetically pleasing, for example with regard to color. The purpose was to solve the problem of producing an alloy that can be manufactured. As a result, 2 for money
An alloy was produced containing 3.76 carats and 1% by weight titanium. This alloy exhibits wear resistance comparable to that of an 18 carat alloy and is particularly claimed in US Pat. No. 1,023,334 and Dutch Patent No. P3502914.5.

In this alloy, titanium is present in the form of titanium nitride by a galvanic treatment for surface hardening which is carried out for the purpose of improving the wear and abrasion resistance of jewelery having a high carat value (A.R. .Zielonka
Written by Gold Technology No. 14, (November 1994)
Month)).

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide Au-Ag-Cu ternary gold alloys having 8 to 22 carats. This gold alloy may contain other elements such as Zn, Ru, Ir, B, Si and In, and also contains titanium.

In particular, titanium replaces the two elements previously used in the manufacture of jewelry, namely nickel and cobalt. These two elements have the drawback of being ferromagnetic, and because of some restrictions in this regard, their presence in alloys may lead to jewelery sales on the market. Limited. In addition, nickel, as is well known, can cause serious allergies to the skin, and in some countries such as Japan, the United Kingdom and Germany, the law prohibits the trading of jewelry containing nickel. It has been done.

Alloys containing approximately 58.5% gold, 5% to 10% silver, 15% to 25% copper, 10% to 20% zinc, and 0.1% to 1% titanium. If used,
Sufficient mechanical resistance and hardness (rebaked (renewed baki
ng) 160 HV, 280 HV after aging, and 8 A
A gold product having an STM grain size) suitable for the above applications is obtained. At the same time, this alloy has a pleasing color similar to that of the most used alloy, which has 18 carats (see table below).

[0017] The alloy hardness of 160HV 280HV crystal grain size 8ASTM 8ASTM after the alloy aging treatment after re-baking

The above characteristics are apparent from the accompanying drawings. FIG. 1 shows the relationship between time and hardness in aging heat treatment.

The particular amounts, expressed in weight percent, of the individual elements will obviously vary as a function of the particular application of the gold alloy. Therefore, the present invention provides a ternary composition of gold, silver and copper.
The present invention provides an alloy containing titanium as a variable component, like the original alloy.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between time and hardness when the alloy of the present invention is aged.

Front page continuation (71) Applicant 595078390 Via Torino 14, ROMANO d'Ezzelino, Vicenza, Italy

Claims (4)

[Claims] 1. A composition having at least a ternary composition of gold, silver and copper, having a composition ratio by weight of 8 to 22 carats, which is suitable for the production of jewelry, coins and gold bars. ,
And a gold alloy that also contains titanium. 2. The alloy of claim 1, wherein the alloy contains gold, silver, copper, and zinc, has 8 to 22 carats, and further contains titanium. 3. The alloy is a ternary alloy containing gold, silver, and copper, having 8-22 carats, and further containing titanium, and small amounts of other elements, namely silicon, boron, The alloy according to claim 1, containing indium, iridium, ruthenium, or the like. 4. A quaternary alloy containing gold, silver, copper and zinc, further containing titanium, having 8 to 22 carats, and containing a small amount of silicon, boron, indium, ruthenium, iridium and the like. The alloy according to claim 2, which contains.