Patent Application
20200308673
The subject invention is directed to alloys for use in making jewelry and, more particularly, to a gold alloy containing not more than about 15% by weight gold, more particularly, in the range of 3 to 6%, approximately for 1 to 2 karats.
There had been an effort by workers in the art to develop gold alloys having the appearance of 10, 12, 14, and 18 karat gold but with a much lower gold content. However, many problems have been encountered in achieving the desired durability, workability, corrosion and tarnish resistance and particularly in simulating the appearance of yellow gold alloys as the percentages of gold have been decreased to provide a lower cost substitute for 10 and higher karat gold. Representative of the efforts of prior art workers are the following patents, U.S. Pat. Nos. 2,141,156; 2,141,157; 2,200,050; 2,216,495; 2,248,100; 2,576,738; 2,654,146; 4,266,973; and 4,276,086. It can be noted that these efforts have all been directed to gold alloys in the 8 to 20 karat range. For example, U.S. Pat. Nos. 2,141,156 and 2,141,157 to Peterson are directed to 8 to 14 karat gold alloys. U.S. Pat. No. 2,200,050 to Auwarter, U.S. Pat. Nos. 2,216,495, and 2,248,100 to Loebich are directed to gold alloys preferably in the 33-45% gold range or above 8 karats. U.S. Pat. No. 2,576,738 to Williams; U.S. Pat. No. 2,654,146 to Mooradian; U.S. Pat. No. 4,266,973 to Guzowski and U.S. Pat. No. 4,276,086 to Murao all deal principally in the 8 to 20 karat range.
The problems of providing a truly low cost substitute for 10 or higher karat gold having the desired color, hue and luster as well as other desirable properties such as resistance to corrosion and tarnishing as well as a reduction of surface roughness have heretofore not been overcome in the prior art. In particular, it has been observed that attempts to produce yellow gold alloys having a gold content in the 5 to 6 karat range have failed to produce an alloy having the color, hue and luster of known yellow gold alloys of 10 and higher karat while exhibiting the good corrosion resistance and surface smoothness also found in 10 or higher karat gold. Otherwise expressed, in the past unless the gold content of the alloy was above 35% of the total weight of the alloy the color, hue and luster thereof was unacceptable for use in the jewelry industry. Although attempts have been made to produce a gold alloy for use in jewelry production having a gold content or less than 30%, the aesthetic appearance of such alloys has generally not been comparable to 10 and higher karat gold. For example, although prior art patents can be found which speak of the broad range of gold content (not the preferred range) as having a lower limit of 25% gold (about 6 karats) e.g., U.S. Pat. No. 2,200,050 to Auwarter, such alloys have been found to clearly lack the color, hue and luster of 10 or higher karat gold. In addition, the Auwarter alloy must contain 2-6% palladium which prevents the alloy from being electropolished. As a result, it would have to be hand polished which takes a considerable amount of time and effort and does not give the quality of an electro-polished alloy.
The alloys of this invention contain less than about 15% by weight gold, but contrasted to prior art alloys nevertheless do have the color, hue and luster of 10 and higher karat gold and, in addition, exhibit good resistance to corrosion and tarnishing, are easily cast, are sufficiently malleable to be easily worked, can be electropolished, can be plated, if desired, can be sized with conventional solders, and can be remelted a number of times. The color, luster, shine and hue of the alloys of the present invention are substantially identical to that of 10 or higher karat gold. These properties are achieved by a yellow gold alloy having the following composition, by weight:
Gold: 3-6%, preferably about 4.17%
Silver: 10-20%, preferably about 16.34%
Copper: 40-80%, preferably about 64.1%
Zinc: 10-20%, preferably about 15.33%
Niobium: 0.01-0.05%, preferably about 0.03%
Cobalt Chrome: 0.010-0.050%, preferably 0.025%
Tantalum: 0.005-0.015%, preferably about 0.01%
The fine gold should be conductive, hypoallergenic, malleable, lustrous and dense. The silver should be conductive, heat treatable, malleable and lustrous. The copper is conductive and malleable. Zinc is conductive, lustrous and dense. The niobium is highly conductive, heat treatable, temperature stable, hypoallergenic and anticorrosive. The cobalt chrome is highly conductive, heat treatable, hypoallergenic and anticorrosive. Finally, tantalum is highly conductive, heat treatable, hypoallergenic and anticorrosive.
The Gold One™ jewelry alloy of the present disclosure is a 1 KT Gold Alloy with unique characteristics for manufacturing fine jewelry, characterized as follows:
The alloy preferably comprises (or consists of) Fine Gold: 4.17%—Conductive, Hypoallergenic, Malleable, Lustrous, Dense; Silver: 16.335%—Conductive, Heat Treatable, Malleable, Lustrous; Copper: 64.1%—Conductive, Malleable; Zinc: 15.33%—Conductive, Lustrous, Dense; Niobium: 0.03%—Highly Conductive, Heat Treatable, Temperature Stability, Hypoallergenic, Anti Corrosive; Cobalt Chrome: 0.025%—Highly Conductive, Heat Treatable, Hypoallergenic, Anti Corrosive; and Tantalum: 0.01%—Highly Conductive, Heat Treatable, Hypoallergenic, Anti Corrosive.
The alloy can be hammered, cast, rolled and made into wire. Thus, the alloy is capable of being formed into a variety of sizes and shapes by techniques traditionally used in the jewelry industry to form jewelry articles of a desired size and configuration. The alloy may also be cut and sized with solders conventionally used in the jewelry industry and can be plated with precious metals such as rhodium if desired.
The alloy may be melted in the 1000°-1100° C. range and cast and shaped with conventional techniques. One of the additional advantages of the alloy is that it can be melted six to seven times whereas 10 and higher karat gold can only be remelted about three or four times before it must be reconstituted.
Unlike known yellow gold alloys, the gold content of the subject invention in the preferred form does not exceed 15% but surprisingly exhibits good resistance to corrosion and tarnishing, good workability and surface smoothness as well as a color, luster, shine and hue at least comparable to 10 karat gold.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.
