VARIABLE KARAT GOLD ALLOYS
A gold alloy that is usable for jewelry and other applications. The gold alloy is made by combining Y % gold with Z % of a master alloy, wherein Y+Z=100. The master alloy includes 16% silver, 71.771% Copper, 12% zinc and 0.229% X, wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof. The gold alloy may be made by first forming the master alloy and then mixing the gold with the master alloy. The gold alloy may also be made by mixing gold with the elements of the master alloy without first forming the master alloy.
This application is a divisional of prior U.S. patent application Ser. No. 12/143,060 filed Jun. 20, 2008, which is incorporated herein by reference.
BACKGROUND OF THE INVENTIONGold has a chemical symbol “Au.” Gold has been a rare and valuable metal for centuries. It is often a symbol of wealth and has been used extensively for jewelry, rings, necklaces, etc. Further, gold is particularly desirable for jewelry in that it retains its beauty and color and does not easily tarnish or corrode. Although gold is generally used for jewelry and wealth, its ability to resist corrosion makes this metal useful for other applications as well (including, for example, dentistry and electronics).
As gold is desired by many people, the price of gold continues to rise. An “ounce” of gold often costs literally hundreds of dollars on the open market. Because of its value, many people have sought to construct alloys of gold that contain lesser and lesser amounts of gold, but still have the appearance and properties of pure gold. Obviously, by reducing the amount of gold in the alloy, the cost of the material decreases (and thus can be used for less expensive jewelry, etc.). At the same time, as the amount of gold decreases, the resulting alloy is less likely to have all of the properties associated with gold. For example, for jewelry made of alloys having lesser amounts of gold, it is has been found that these materials are more likely to tarnish and can even cause a person's skin to discolor. Clearly, such properties are undesirable and inhibit the jeweler's ability to sell its product.
In the jewelry industry, the amount of gold in a particular alloy is often measured in terms of “karats.” Pure gold (i.e., 100% gold) is referred to as 24 karat gold. Thus, the number of “karats” in the gold divided by 24 yields the percentage of gold in the alloy. For example, an alloy of gold that has 50% gold would be referred to as a 12 karat gold. 18 karat gold would be an alloy that has 75% gold, etc. Some of the desirable properties of gold includes its color, its “workability” (i.e., its ability to be shaped, malleability) and its flow characteristics.
However, as noted above, as the amount of gold in the alloy decreases (i.e., the number of karats decreases), the material is less likely to have the properties of pure gold. Thus, jewelers are interested in finding new alloys that could be classified as 5 karat golds, 6 karat golds, 3 karat golds, etc., but yet still have the properties/appearance of gold and could be used as suitable jewelry pieces. For example, many jewelers use alloys that include platinum, palladium, or other “platinum group metals” in their alloys to form 6 karat gold (or other low karat gold alloys). Unfortunately, these metals are often very expensive. Thus, using these metals in the gold alloy does not lower the price of the jewelry piece. U.S. Pat. No. 4,446,102 is another example of a low karat gold alloy that does not use a platinum group metal. (This patent is expressly incorporated herein by reference). However, this patent does not seem to be commercially successful and, if used in jewelry, will tarnish after being worn extensively by a user.
In fact, currently there does not appear to be on the market a 6 karat gold (or low karat gold) that (1) does not include an expensive platinum group metal and (2) does not tarnish after being worn for extended periods of time. Accordingly, there is a need in the industry for a new alloy of gold that may be used as a low karat alloy that is suitable for most jewelry applications. This alloy should not tarnish or discolor the skin if used as a jewelry piece. Such an alloy is taught herein.
The nomenclature that is used herein will be as follows. It is noted that in the United States, the Federal Trade Commission (“FTC”) has placed regulations on a party's use of the term “karat gold” for those alloys that are less than 10 karats (i.e., less than 41.67% gold). See 16 C.F.R. Part 23. However, other countries do not have these types of restrictions regarding use of the word “karat.” For purposes of this application, this FTC labeling requirement will not apply. References to a variable karat gold alloy or a low karat gold alloy include those alloys which are less than 10 karats, even down to 0 karats (in which there is no gold present in the alloy). Such alloys, however, are clearly “precious metal alloys.” Accordingly, these alloys may also be referred to as precious metal alloys.
BRIEF SUMMARY OF THE INVENTIONThe present embodiments teach a new type of gold alloy and a method of making this gold alloy. Generally, these embodiments involve the use of a master alloy. This master alloy has the composition of 16% silver, 71.771% copper, 12% zinc, and 0.229% X, wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof. This master alloy may then be mixed with an amount of gold to form a gold alloy. In other words, the gold alloy will comprise Y % gold and Z % of a master alloy, wherein Y+Z=100.
It should be noted one of the embodiments involves pre-forming the master alloy and then mixing a desired percentage of the master alloy with a desired percentage of gold to form the resulting gold alloy. However, other embodiments may be designed in which the gold alloy is made by mixing gold with the elements of the master alloy without first forming the master alloy.
In some embodiments, the gold alloy formed may be a 6 karat gold alloy such that the percentage of gold (Y) is 25% and the percentage of the master alloy (Z) is 75%. In this embodiment, the overall formula of the composition is;
25% Au;
12% Ag;
53.828% Cu;
9% Zn; and
0.172% of X, where X is silicon, germanium and/or mixtures of silicon and germanium.
In some embodiments, the gold alloy formed may be a 3 karat gold alloy such that the percentage of gold (Y) is 12.5% and the percentage of the master alloy (Z) is 87.5%. In this embodiment, the overall formula of the composition is;
12.5% Au;
14% Ag;
62.799% Cu;
10.5% Zn; and
0.201% of X, where X is silicon, germanium and/or mixtures of silicon and germanium.
In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawing in which:
The presently preferred embodiments of the present invention will be best understood by reference to the drawing. It will be readily understood that the components of the present invention, as generally described and illustrated in the figure herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the present invention, is not intended to limit the scope of the invention, as claimed, but is merely representative of presently preferred embodiments of the invention.
The present embodiments relate to novel types of gold alloys, and more particularly, low karat gold alloys. These gold alloys do not tarnish during extended use and wear, and will have the appearance of pure 24 karat gold, yet still only have lower amounts of gold in the composition, such as 25% gold, 12.5% gold, etc. Even “zero karat” gold—i.e., an alloy that does not have any gold in it, may be made. This zero karat gold will have the appearance of karat gold and exhibits lower tarnish characteristics than other non-gold alloys, but is obviously less expensive to make given the lack of gold in the composition. This zero karat alloy may be referred to as a “gold-tone” alloy.
Referring now to
The gold 12 is mixed with a master alloy 16 to obtain the variable karat gold alloy 10. The percentage of the master alloy 16 is represented by the variable “Z.” Specifically Y % Au 12 will be mixed with Z % master alloy 16 to form the variable karat gold alloy 10. Obviously, the percentages of gold and master alloy must add up to 100% (i.e., Y+Z=100).
The master alloy is made up of silver (whose chemical symbol is “Ag”), copper (whose chemical symbol is “Cu”), zinc (whose chemical symbol is “Zn”) and silicon (whose chemical symbol is “Si”) and/or germanium (whose chemical symbol is “Ge”). These elements are mixed in the following composition:
16% silver;
71.771% copper;
12% zinc; and
0.229% X, wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof.
It should be noted that in the embodiment shown in
Examples of the variable karat gold alloy 10 will now be provided. Specifically, if a 6 karat gold alloy were desired, 25% gold would be mixed with 75% of the master alloy. Once mixed and the alloy formed (using standard methods known in the industry), the resulting alloy would have the following composition:
25% Au;
12% Ag;
53.828% Cu;
9% Zn; and
0.172% of X, X is silicon, germanium and/or a mixture of silicon and germanium. This 6 karat gold composition does not tarnish, is wearable, will not discolor the wearer's finger or skin, and has the appearance of 14 karat gold. Accordingly, this composition is desirable. Further, this alloy will have the color of karat gold and will have the flow characteristics and workable nature of karat gold. Any number of other gold alloys may be constructed in a similar manner. For example, if a 3 karat gold is desired, this gold may be constructed by taking 12.5% and mixing with 87.5% of the master alloy composition.
Obviously, those skilled in the art will appreciate that any number of gold alloys may be made in a similar manner (in addition to the 3 karat or 6 karat gold alloys described above). Those skilled in the art would understand how to mix the elements together to get any desired gold alloy. Specifically, using these methods, a 0 karat gold alloy could be constructed in which the Y percentage of gold is 0 and the Z percentage of the master alloy is 100. 2 karat gold alloy could be constructed in which the Y percentage of gold is 8.33% and the Z percentage of the master alloy is 91.67%. Other embodiments may be designed. For example, an alloy that is less than or equal to 20 karat gold would have a Y percentage of gold is less than or equal to about 83.33%. Further embodiments may be designed in which the alloy that is less than or equal to 10 karat gold, such that the Y percentage of gold is less than or equal to about 41.67%. Yet additional embodiments may be designed in which the alloy is less than or equal to 6 karat gold, such that the Y percentage of gold is less than or equal to about 25%. Any other type of gold alloy may be constructed, as will be appreciated by those skilled in the art. Further, any of the above-recited alloys may be made by constructing the master alloy first, or by simply mixing the elements together without pre-forming a master alloy.
Once the gold alloy has been formed (by mixing an amount of the master alloy with the amount of the pure gold), a skilled artisan will be able to determine and calculate exactly how much silver, copper, etc., is in the resulting alloy. However, the following ratios are helpful in explaining the present embodiments. As noted above, in the pure (100%) master alloy, there is 16% Silver. The percentage of silver in the formed gold alloy will be proportionally decreased based upon the amount of amount of gold added to the resulting compound. Using basic rules of portions, the following mathematical relationship can be rewritten
Where ZAg represents the percentage of silver in the resulting gold alloy and AMA represents the percentage of the master alloy used to form the gold alloy.
However, it is known that the percentage of the master alloy (AMA) plus the percentage of the gold (Y) must equal 100. Accordingly:
Y+AMA=100. (Equation 2)
Or in other words, AMA=100−Y. (Equation 3)
Substituting this relationship into Equation 1 renders the following:
If Equation 4 is solved for ZAg, the following is obtained:
ZAg=(1600−16* Y)/100 (Equation 5)
which represents the percentage of silver that will be in the resulting gold alloy given as a function of the percentage of gold (represented as variable “Y”) used to form the composition.
In addition to the 16% silver in the master alloy, there is 71.771% copper, 12% zinc and 0.229% X (wherein X is Si, Ge, or mixtures thereof). Similar mathematical ratios can be derived for each of these components in the same way. Accordingly, the following equations give the percentages of Cu, Zn, and X existing in the resulting gold alloy as a function of the percentage of gold added to form the composition:
ZZn=(1200−12*Y)/100 (Equation 6)
wherein Y represents the percentage of gold added to form the composition and ZZn, is the percentage of zinc in the resulting alloy;
ZCu=(7177.066667−71.7706667*Y)/100 (Equation 7)
wherein Y represents the percentage of gold added to form the composition and ZCu is the percentage of Cu in the resulting alloy; and
Zx=(22.933333−0.2293333*Y)/100 (Equation 8)
wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof, wherein Y represents the percentage of gold added to form the composition and Zx is the percentage of X in the resulting alloy.
Those skilled in the art will appreciate that if Y is set at “25” (i.e., 25% gold) in Equations 5-8, the composition of the 6 karat gold alloy noted above will be obtained. Likewise, if Y is set at “12.5” (i.e., 12.5% gold) the composition of the 3 karat gold alloy noted above will be obtained. Those skilled in the art will appreciate that these equations may be used to calculate the percentages of each element needed based upon the percentage of gold in the final alloy. Further, the above-recited equations are but one way of calculating the amount of each element in the resulting alloy; other types of similar equations and/or scaling factors are clearly possible.
Equations 5 through 8 noted above provide an easy way for a skilled artisan to determine the amount of each element to be added to the resulting alloy. Thus, the user (as noted above) may not need to pre-form the master alloy before making the gold alloy. Rather, all that is required is to mix the elements into an alloy based upon the percentages obtained from Equations 5 through 8. Examples showing the formulas for some karat golds less than or equal to 20 karats are given in Table 1.
The above-recited embodiments include alloys for gold that have less than 4 karats. It should be noted that, in some embodiments, these alloys having less than 4 karats (i.e., alloys having less than about 16% gold), may not be as tarnish-resistant as other alloys. Rather, based upon the usage and wear, some of these embodiments with less than 16% gold may tarnish when brought into contact with the skin after long periods. Accordingly, such embodiments with less than 16% gold may not be as preferred as other embodiments for use in rings and other jewelry applications. Such alloys with less than 16% gold may still be suitable for tie-tacks or other jewelry that is not generally worn in contact with the skin. In other situations, such alloys with less than 16% gold may still be sufficiently tarnish resistant that they may be worn on the skin.
It should also be noted that the composition of the master alloy provided herein may be modified as follows. In fact, various ranges may be used for each of the component elements. For example, the following ranges may be used for a 6 karat gold alloy:
From about 61.77 to about 81.77% Cu, and more preferably from about 56.77 to about 76.77% Cu;
from about 2 to about 22% Zn, and more preferably from about 7 to about 17% Zn; from about 6 to about 26% Ag, and more preferably from about 11 to about 21% Ag; from about 0.001 to about 2% X, and more preferably from about 0.01 to about 1.00% X,
wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof. Thus, even if the composition is varied within the ranges specified herein, the resulting alloy will still have the color, flow characteristics, and workability associated with gold. This would result in the following ranges in composition for the resulting 6 karat gold alloy:
from about 43 to about 63% Cu, and more preferably from about 48 to about 58% Cu;
from about 2 to about 16% Zn, and more preferably from about 4 to about 14% Zn;
from about 2 to about 22% Ag, and more preferably from about 7 to about 17% Ag;
from about 0.001 to about 2% X, and more preferably from about 0.01 to about 1.00% X,
wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof.
It will also be appreciated that any and/or all of embodiments described herein may include one or more grain refiners. Those skilled in the art will appreciate that such grain refiners could be boron, magnesium, phosphorus, or other elements. Such grain refiners may be added up to 1.5%, and more preferably, up to 1%, without changing the properties of the alloy. Accordingly, those skilled in the art would appreciate how to implement and use these grain refiners.
It should be noted that the present application gives various examples of the alloys described herein used in the jewelry industry or in jewelry application. Those skilled in this industry will appreciate that there are a variety of different applications for the alloys described herein, including dental applications, aerospace applications, metallurgy applications, electronic devices, etc. Any application or field interested in these gold alloys could potentially use or be interested in the present alloys. Further, another application includes using the alloys disclosed herein as a powder coating. In these applications, a powder of the alloy (such as, for example), the 6 karat alloy could be laser sintered to any substrate. Once sintered, this powder coating retains the same properties of the alloy, thus allowing this coating to be added to a substrate.
It is also worth noting that there are a variety of different ways known in the industry that the alloys described herein could be added or used. For example, such alloys may be used as part of plating solutions. Other embodiments may have these alloys electrically deposited onto a substrate. Further application may use the alloys as part of clad materials or layer materials (i.e., where the alloy is a foil on a brass substrate (such that the customer only sees the gold layer on the outside). Materials filled with these gold alloys may also be used. Findings, wires and rods, and other accessories may be made using these alloys. Again, the processes used (plating, making clad materials, etc.) as well as the types of materials that can be made using these alloys involve standard techniques known in the gold/metallurgical industry. Those skilled in the art will appreciate that all such techniques could be used.
The above-recited embodiments relate to “yellow gold,” but similar concepts could be applied to white gold alloys. For example, following white gold alloy could be made as follows:
Each of the above recited alloys are 6 karat white gold alloys as they have 25% gold. These alloys could also be used with up to 1.5%, and more preferably, up to 1.0% grain refiners, as noted above. Such white gold alloys are premium white in color and rhodium plating is unnecessary. These alloys have an 18 Karat White gold appearance. All white and yellow gold alloys are composited without platinum group elements. Grain refiners do not significantly affect the color or tarnish resistance of the alloy but may have an affect on other properties.
The white gold alloys may have different compositions than that which was noted above. For example, the following ranges may be used for a 6 karat white gold alloy:
from about 15 to about 52% Cu, and more preferably from about 20 to about 47% Cu;
from about 3.5 to about 35% Ni, and more preferably from about 8.5 to about 30% Ni;
from about 0 to about 30% Zn, and more preferably from about 5 to about 25% Zn;
from about 5 to about 25% Ag, and more preferably from about 10 to about 20% Ag;
Again, for all of these alloys within the ranges, grain refiners may be used from up to about 1.5%, and more preferably, up to about 1%. Such white gold alloys are premium white in color and rhodium plating is unnecessary. These alloys have an 18 Karat White gold appearance. All white and yellow gold alloys are composited without platinum group elements.
As with the embodiments discussed above, the present embodiments of white gold may also be made by constructing a master alloy and then mixing this master alloy with a quantity of gold to create the desired composition. Likewise, the gold and other elements may be mixed together (without first forming a master alloy) to create the desired alloy.
For example, a master alloy could be made with the following formula that would be useful for making white gold:
33.333% Cu;
33.333% Ni;
13.333% Zn; and
20% Ag.
Again, this master alloy could then be mixed with various amounts of gold to create a white gold. For example, this master alloy may be made and then mixed with gold such that there is 25% gold and 75% of the master alloy in the final mixture, thereby creating a 6 karat white gold. If 50% of the master alloy is mixed with 50% gold, a 12 karat white gold is formed. Those skilled in the art would appreciate that additional types of gold alloys may be formed. Similarly, those skilled in the art would appreciate that the white gold alloy may be constructed without first creating the master alloy. Rather, using the techniques described herein, the exact weight percentages of the gold, copper, nickel, silver, and zinc may be mixed together to form the desired white gold alloy.
The above recited master alloy may be modifies as follows:
The amount of copper may be from about 23.333% to about 43.333%, and more preferably from about 28.333% to about 38.333%;
The amount of nickel may be from about 23.333% to about 43.333%, and more preferably from about 28.333% to about 38.333%;
The amount of zinc may be from about 3.333% to about 23.333%, and more preferably from about 8.333% to about 18.333%; and
The amount of silver may be from about 10% to about 30%, and more preferably from about 15% to about 25%.
Again, one or more grain refiners, up to about 1.5% and more preferably up to about 1.0% may be used as well.
Another master alloy for use in making white gold compositions could have the following composition:
55.333% Cu;
18% Ni; and
26.667% Zn.
This master alloy could then be mixed with various amounts of gold to create various alloys of white gold, as taught herein. This master alloy could be modified as follows:
The amount of copper may be from about 45.333% to about 65.333%, and more preferably from about 50.333% to about 60.333%;
The amount of nickel may be from about 8% to about 28%, and more preferably from about 13% to about 23%; and
The amount of zinc may be from about 16.667% to about 36.667%, and more preferably from about 21.667% to about 31.667%;
One or more grain refiners, up to about 1.5% and more preferably up to about 1.0% may be used as well.
A third master alloy for use in making white gold compositions could have the following composition:
56% Cu;
29.333% Ni; and
14.667% Zn.
This master alloy could then be mixed with various amounts of gold to create various alloys of white gold, as taught herein. This master alloy could be modified as follows:
The amount of copper may be from about 46% to about 66%, and more preferably from about 51% to about 61%;
The amount of nickel may be from about 19.333% to about 39.333%, and more preferably from about 24.333% to about 34.333%; and
The amount of zinc may be from about 4.667% to about 24.667%, and more preferably from about 9.667% to about 19.667%;
One or more grain refiners, up to about 1.5% and more preferably up to about 1.0% may be used as well.
A fourth master alloy for use in making white gold compositions could have the following composition:
53.333% Cu;
28% Ni; and
18.667% Zn.
This master alloy could then be mixed with various amounts of gold to create various alloys of white gold, as taught herein. This master alloy could be modified as follows:
The amount of copper may be from about 43.333% to about 63.333%, and more preferably from about 48.333% to about 58.333%;
The amount of nickel may be from about 18% to about 38%, and more preferably from about 23% to about 33%; and
The amount of zinc may be from about 8.667% to about 28.667%, and more preferably from about 13.667% to about 23.667%;
One or more grain refiners, up to about 1.5% and more preferably up to about 1.0% may be used as well.
Again, all of these master alloys described herein could be used to form white gold alloys with any desired gold content. Those skilled in the art will appreciate how this may be accomplished.
A more general master alloy for the white gold may be of the formula
from about 43.33% to about 66% copper;
from about 8 to about 39.33% nickel; and
from about 4.67% to about 36.67% zinc.
This formula may, of course, include one or more grain refiners and may be used to form variable karat white gold alloys. Specifically, all of the master alloys for the white golds may be combined with gold, as taught herein, to form different gold alloys. For example, if these master alloys are combined with 50% gold, then there will be 12 karat gold alloy formed. If these master alloys are combined with 12.5% gold, then a 3 karat gold alloy is formed.
The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
1-13. (canceled)
14. A method of forming a gold alloy comprising the steps of:
- adding Y % gold;
- adding ZAg % silver, wherein ZAg=(1600−16*Y)/100;
- adding ZZu % zinc, wherein ZZu=(1200−12*Y)/100;
- adding ZCu % copper, wherein ZCu=(7177.066667−71.77066667*Y)/100;
- adding ZX % X, wherein X being selected from the group consisting of silicon, germanium, or mixtures thereof, wherein Zx=(22.9333−0.2293333*Y)/100.
15. A method as in claim 14 wherein the non-gold elements are first mixed together to form a master alloy, wherein the master alloy is mixed with gold to form the gold alloy.
16-17. (canceled)
Type: Application
Filed: Mar 28, 2011
Publication Date: Sep 22, 2011
Inventor: Annette Gertge (Cottonwood Heights, UT)
Application Number: 13/073,199
International Classification: C22C 1/00 (20060101);
