MXPA97005001A - An alloy of - Google Patents

Abstract

The alloy is based on gold and is suitable for use in the field of jewelry, for the production of jewelry, coins and gold bars, with a variable title between 8-22 carats and has a variable percentage of other components, among which silver, copper, zinc in a ternary alloy, quaternary alloy and others. The alloy contains the titanium element. A satisfactory relationship is achieved between the aging time and hardness in the heat treatment carried out during the aging process.

Description

A GOLDEN ALLOY FIELD OF THE INVENTION The present invention relates to alloys made of gold, useful in the field of jewelry for the production of jewelry, coins and bars made of gold with a title, which varies between 8 carats and 22 carats, with different percentages of other components among which are silver, copper and zinc and characterized by the presence of titanium, which is the object of the present invention.

BACKGROUND OF THE INVENTION It is well known that pure gold is extremely soft and that in the production of jewelry items it is necessary to use a material, which has particular properties of hardness, resistance to wear and at the same time, should retain a striking and bright color. The hardness of the alloy is due to the precipitation phenomena in the solid phase, as well as the disorder-order transition phenomena, which occurs below certain temperatures in particular atomic relationships between the elements of the alloy. It is at this point, that titanium is inserted into the composition and titanium, due to the fact that it participates for the phenomena mentioned in the above precipitation, imparts new properties to the alloy. The gold alloys in general, are made of a ternary system Au-Ag-Cu and in the trade are available with different titles between 8 and 24 carats. The intermediate titles in the trade are 9, 10, 12, 14, 18, 20, 21 and 22 carat. Until very recent times, the study of gold, a metal used for centuries for decorative purposes, besides all due to the particular color and resistance to staining, has been limited to alloys, which are easily workable and with a pleasant color. In view of the increase in the price of gold, which in certain times has reached over $ 800 per ounce, it is evident that it has become necessary to use lighter, but equally resistant jewelry. In addition, for the more colorful items, particularly bracelets (hollow), earrings made with a circle and finally the production of very thin similar chains, for example to the products listed in the Italian patent application VI95A000085 of the same applicant, more products are required light, more resistant, not only for economic reasons, but also aesthetic reasons. This requirement is responsible for the fact that other pure metals have been added to three elements listed in the above for the purpose of preparing alloys for jewelry. The metal which is mostly being used to form the common quaternary alloy is zinc, which is added in small amounts, less than 0.5% as a deoxidizing material or in larger quantities, for example, up to 10% or more, to modify the color, the workability and the mechanical properties of the alloy. The combination, gold, silver, copper and zinc, is essentially all gold alloys commonly used for jewelry. These alloys may be different from one another, due to the addition of the four basic elements in small amounts of other metals such as nickel, cobalt, iron, silicon, boron, ruthenium, iridium, indium or others. By way of example, the patents that describe what has been summarized in the foregoing and which shows the variety of components that are used to form a gold alloy are: - USP No. 2,141,157 in the name of Peterson, which contains 33 % -84% gold, 10% -67% copper, 2% -10% * zinc, 2% -10% silver and 0.1% -5% cobalt. In the alloy, the cobalt is being used to obtain the reversible hardening.

- USP No. 2,229,463 in the name of Leach, which contains 35% -75% gold, 5% -25% silver, 12% -35% copper, 0.1% -12% zinc, and 1% -5% iron. In this alloy, the iron is used to obtain both reversible hardening, as well as irreversible hardening. - USP No. 2, 248,100 in the name of Loebich, which contains 33% -66% gold, l% -30% silver, 10% -55% copper, 0.5% -15% zinc and 0.1% -5% iron. - USP No. 3,981,723 describes a white gold alloy which contains palladium, silver, indium and 0.005% iridium or ruthenium. The most recent patents describe alloys such as USP No. 5,180,551 in the name of Leach and Garner and USP No. 5,173,132 in the name of Solomon. In these patents different combinations of cobalt and nickel are used for the purpose of improving grain structure, optimizing color and increasing mechanical strength. It is clear from the above list of patents, with respect to the state of the art in the field of jewelery products, that the titanium element does not appear because the work of the alloys which contain this element, requires particular caution due to the high activity at high temperature with air, oxygen, nitrogen, carbon which are commonly present in the formation of the protective atmosphere during the treatments of solubilization, aging, cold work, melting or others. The only gold alloy known today, which contains titanium is the alloy known as "gold 990". This alloy has a high kilataje and is the result of the study carried out in the period of 1970 and the purpose was to solve two types of problems, hardening an alloy with very low percentage of elements that form the alloy and at the same time produce a alloy, which is aesthetically satisfactory, for example with respect to color. The result has been that an alloy with carat of 23.76 in gold and 1% by weight of titanium has been made. That alloy has offered wear resistance equal to an 18-carat alloy and has been claimed in particular in USP 1,023,334 and German Patent No. P35 02 914.5. Titanium is present in this alloy in the form of titanium nitride and the galvanic treatment of surface hardening for the purpose of increasing the wear and abrasion resistance of jewelry items having high carats (see AR Zielonka Gold Technology No. 14 , November 1994).

BRIEF DESCRIPTION OF THE INVENTION The object of the present invention is to provide a gold alloy having between 8 and 22 carats with the ternary system Au-Ag-Cu, which may include other elements such as Zn, Ru, Ir, B, * Si, In or others and which contain the titanium element. In particular, the substitutes of titanium in practice, two elements which up to the present time have been used in the production of jewelry, is nickel and cobalt. These two elements have the disadvantage that they are ferromagnetic and their presence in the alloy limits the sale of jewelry in the market, in which there are some laws of restriction in this regard. In addition, nickel, as is well known, can cause serious types of skin allergy to such an extent that in several countries, such as Japan, England and Germany, laws have been made which prevent the marketing of jewelry items, which contain nickel. An alloy containing approximately 58.5% gold, 5% -10% silver, 15% -25% copper, 10% -20% zinc and 0.1% -1% titanium, you get a gold product suitable for the uses described above, of sufficient mechanical strength and hardness (160 HV with renewed baking and 280 HV with the aging treatment and with a grain size of 8 ASTM). At the same time, the alloy has a nice color similar to the 18-carat alloy which is the most commonly used alloy - see the following table. alloy baked alloy - after the aging treatment hardness 160 HV 280 HV grain dimension 8 ASTM 8 ASTM The properties mentioned in the above are also clear from the appended figures: * Figure 1 which illustrates the relationship between time and hardness in the heat treatment of aging. The specific amounts of the individual pure metals, expressed in percents, by weight vary clearly as a function of the specific uses of the gold alloy. The invention, therefore, consists in providing an alloy having a ternary composition of gold, silver, copper and with variable titanium as well as alloys of a quaternary type and others.

Claims (4)

1. A gold alloy, characterized in that it comprises at least one ternary composition of gold, silver and copper, which has 8-22 carats in various percentages of the compositions by weight and suitable for the production of jewelery, coins and gold bars and which also comprise titanium.

2. The alloy in accordance with the claim 1, characterized in that the alloy is a quaternary alloy containing gold, silver, copper and zinc, which has between 8 and 22 carat and also contains titanium.

3. The alloy in accordance with the claim 1, characterized in that the alloy is a ternary alloy with gold, silver and copper, has 8-22 carats and additionally contains titanium and which comprises small amounts of other elements, the elements are silicon, boron, indium, iridium, ruthenium or other .

4. The alloy in accordance with the claim 2, characterized because it is a quaternary alloy containing gold, silver, copper and zinc, and additionally titanium, the alloy has 8-22 carats and has small amounts of the elements silicon, boron, indium, ruthenium, iridium or others.