U.S. patent application number 13/113690 was filed with the patent office on 2012-11-29 for white tungsten carbide jewelry article.
This patent application is currently assigned to Stuller, Inc.. Invention is credited to Glenn A. Miller.
Application Number | 20120297825 13/113690 |
Document ID | / |
Family ID | 47215870 |
Filed Date | 2012-11-29 |
United States Patent
Application |
20120297825 |
Kind Code |
A1 |
Miller; Glenn A. |
November 29, 2012 |
White Tungsten Carbide Jewelry Article
Abstract
An improved jewelry article with a brilliant, preferably white,
coating securely bonded to a substrate. The coating comprises
predominantly chromium and, where a white finish is desired, a
platinum group metal, preferably platinum. The substrate comprises
predominantly tungsten carbide and a substantial amount of metal,
preferably nickel. The coating is applied to the substrate using
vapor deposition, such as physical vapor deposition. The metal and
especially nickel will facilitate adhesion between the chromium in
the coating and the substrate. The vapor deposition will further
provide for superior adhesion as compared to traditional plating
techniques. The improved jewelry article will maintain the
brilliant, preferably white, finish of the coating due to the hard
scratch resistant predominantly chromium coating and the improved
adhesion between the coating and substrate.
Inventors: |
Miller; Glenn A.;
(Lafayette, LA) |
Assignee: |
Stuller, Inc.
Lafayette
LA
|
Family ID: |
47215870 |
Appl. No.: |
13/113690 |
Filed: |
May 23, 2011 |
Current U.S.
Class: |
63/13 ; 427/250;
427/528; 63/12; 63/15; 63/3; 63/34 |
Current CPC
Class: |
C23C 14/16 20130101;
B22F 2998/00 20130101; A44C 27/006 20130101; C22C 29/08 20130101;
A44C 27/003 20130101; B22F 9/04 20130101; B22F 2998/00 20130101;
C22C 27/06 20130101 |
Class at
Publication: |
63/13 ; 63/12;
63/3; 63/15; 63/34; 427/528; 427/250 |
International
Class: |
A44C 25/00 20060101
A44C025/00; A44C 5/00 20060101 A44C005/00; A44C 9/00 20060101
A44C009/00; A44C 7/00 20060101 A44C007/00; A44C 15/00 20060101
A44C015/00 |
Claims
1. A improved jewelry article comprising: a substrate having an
exterior surface, said substrate comprising predominantly tungsten
carbide by weight, said substrate further comprising metal, said
metal comprising at least about twenty percent of said substrate by
weight; a coating secured to said substrate via vapor deposition;
said coating comprising predominantly chromium.
2. An improved jewelry article according to claim 1 wherein said
coating covers substantially all of said exterior surface of said
substrate.
3. An improved jewelry article according to claim 2 wherein said
metal comprises at least about twenty-seven percent of said
substrate by weight.
4. An improved jewelry article according to claim 2 wherein said
metal comprises nickel and alloys thereof.
5. An improved jewelry article according to claim 4 wherein said
nickel is dispersed throughout said substrate.
6. An improved jewelry article according to claim 5 wherein said
metal further comprises molybdenum.
7. An improved jewelry article according to claim 6 wherein said
molybdenum is dispersed throughout said substrate.
8. An improved jewelry article according to claim 7 wherein said
coating further comprises a metal selected from the group
consisting of ruthenium, rhodium, palladium, osmium, iridium, and
platinum.
9. An improved jewelry article according to claim 5 wherein said
coating further comprises a metal selected from the group
consisting of ruthenium, rhodium, palladium, osmium, iridium, and
platinum.
10. An improved jewelry article according to claim 9 wherein said
coating is white.
11. An improved jewelry article according to claim 1 wherein said
substrate is selected from the group consisting of rings, earrings,
necklaces, bracelets, and pendants.
12. An improved jewelry article according to claim 11 wherein said
substrate is a ring.
13. An improved jewelry article according to claim 1 wherein said
substrate is formed by sintering.
14. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article comprising: applying a
coating to a substrate via vapor deposition, said coating
comprising predominantly chromium; said substrate having an
exterior surface, said substrate further comprising predominantly
tungsten carbide by weight, said substrate further comprising
metal, said metal comprising at least about twenty percent of said
substrate by weight.
15. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 14
wherein said coating is applied to substantially all of said
exterior surface of said substrate.
16. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 15
wherein said metal comprises at least about twenty-seven percent of
said substrate by weight.
17. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 15
wherein said metal comprises nickel.
18. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 17
wherein said nickel is dispersed throughout said substrate.
19. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 18
wherein said metal further comprises molybdenum.
20. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 19
wherein said molybdenum is dispersed throughout said substrate.
21. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 20
wherein said coating further comprises a metal selected from the
group consisting of ruthenium, rhodium, palladium, osmium, iridium,
and platinum.
22. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 18
wherein said coating further comprises a metal selected from the
group consisting of ruthenium, rhodium, palladium, osmium, iridium,
and platinum.
23. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 22
wherein said coating is white.
24. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 14
wherein said substrate is selected from the group consisting of
rings, earrings, necklaces, bracelets, and pendants.
25. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 24
wherein said substrate is a ring.
26. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 15
wherein said vapor deposition comprises physical vapor
deposition.
27. A method of applying a scratch resistant coating with a high
degree of adhesion to a jewelry article according to claim 26
wherein said physical vapor deposition comprises sputtering.
28. An improved jewelry article according to claim 27 wherein said
substrate is formed by sintering.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to the field of coated
jewelry in general and more specifically to tungsten carbide
jewelry coated with a wear-resistant layer.
[0003] 2. Prior Art
[0004] The use of tungsten carbide for jewelry is well known in the
art. Tungsten carbide can be used to create any article of jewelry
but is particularly popular in crafting wedding bands and
particularly men's wedding bands. Tungsten carbide is known for its
hardness and density, making it a suitable material for use in
jewelry that will be worn everyday or subjected to harsh
conditions. Tungsten carbide rings are known for their dark,
lustrous gray color. There is a market for jewelry, particularly
rings, in the distinct color of tungsten carbide, and the jewelry
can be polished to a minor-like shine which is easily retained
because of the hardness of the material.
[0005] There are many other traditional metals for use in jewelry
and particularly wedding bands. The most common metal for use in
wedding bands is gold. Whether yellow, white or rose in color, gold
is popular for jewelry, particularly wedding bands because it is
traditional and easily engraved. However, gold is not as durable as
tungsten carbide and may need to be repolished due to scratching.
Platinum is another popular metal for jewelry, particularly wedding
bands. However, platinum is one of the most valuable of the
precious metals, making it cost prohibitive to some potential
buyers. Silver is a cost effective alternative to platinum and
provides the same white color and can be polished to a similar
brilliant shine. However, unlike either white gold or platinum,
common silver alloys easily tarnish and must be polished regularly
to maintain their finish.
[0006] White gold, platinum, and silver have one important thing in
common, their brilliant white color. This color gives jewelry made
of these metals a classic, understated appearance and makes all
three of these precious metals very popular choices for jewelry,
especially wedding rings. As discussed above, rings made of
tungsten carbide have a distinctive dark gray color similar to that
of hematite and not the brilliant white color of white gold,
platinum, and silver. However, jewelry, particularly rings, made of
tungsten carbide overcomes some of the problems associated with
other precious metals. For instance, unlike gold, tungsten carbide
is scratch resistant; unlike platinum, tungsten carbide is cost
efficient. Lastly, unlike silver, tungsten carbide does not require
constant maintenance. Therefore, in light of the above, there is a
distinct need for a jewelry article comprising tungsten carbide
that meets the following objectives.
OBJECTS OF THE INVENTION
[0007] It is an object of the invention to provide an improved
jewelry article that comprises tungsten carbide and is white in
color.
[0008] It is yet another object of the invention to provide an
improved jewelry article that comprises tungsten carbide and is
white in color due to a coating affixed to the tungsten
carbide.
[0009] It is still another object of the invention to provide an
improved jewelry article that combines the durability of tungsten
carbide with the aesthetic appeal of platinum group metals.
[0010] It is a further object of the invention to provide an
improved jewelry article that is resistant to scratching.
[0011] It is a still further object of the invention to provide a
coating that will vigorously adhere to a tungsten carbide jewelry
article.
SUMMARY OF THE INVENTION
[0012] The invention comprises an improved jewelry article with a
brilliant, preferably white coating bonded to a substrate
comprising tungsten carbide. The improved jewelry article will
maintain the brilliant, white finish of the coating due to
increased scratch resistance and improved adhesion between the
coating and substrate. The coating comprises chromium and a
platinum group metal, preferably platinum. The substrate comprises
tungsten carbide and an effective amount of metal, and especially
nickel. The coating is bonded to the substrate using vapor
deposition. The result is a coating that provides a brilliant,
white finish that is resistant to scratching and that strongly
adheres to the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an illustration of various jewelry articles that
can be made according to the present invention.
[0014] FIG. 2 is a perspective view of a ring made according to the
present invention.
[0015] FIG. 2A is a cross-section of the ring shown in FIG. 2 with
the coating shown enlarged for illustration purposes.
DETAILED DISCLOSURE OF THE INVENTION
[0016] An improved jewelry article 1 is disclosed. Improved jewelry
article 1 can be a variety of jewelry pieces such as rings 2,
earrings 3, pendants 4, cufflinks 5, chains 6, bracelets 7,
necklaces 8, money clips 9 or any other accessory for which the
user desires a brilliant long lasting finish. The improvements
disclosed herein are particularly useful on jewelry articles 1
which endure particularly rough or sustained wear such as wedding
bands or money clips 9 carried in the user's pocket.
[0017] The improved jewelry article 1 provides the desired
brilliant white finish similar to that commonly found in white
gold, platinum, and silver articles or custom nickel plated
articles. The durability of the article is simultaneously improved
by applying a coating 11 that will sustain the polished finish
through increased wear and tear. Furthermore, the overall cost of
the jewelry article 1 may be controlled by applying coating 11,
comprising a small percentage of a platinum group metal over a
substrate 10 which comprises more cost efficient materials
including tungsten carbide.
[0018] Substrate 10 of improved jewelry article 1 comprises
tungsten carbide. Tungsten carbide is known for its durability,
resistance to scratching and brilliant dark finish. Jewelry
articles, particularly men's wedding bands, comprising tungsten
carbide commonly include nickel as binder, and nickel is a common
binder for tungsten carbide articles in general. It increases the
corrosion resistance of the tungsten carbide. In the present
embodiment, the nickel binder percentage has been increased to
exploit another property of nickel which is not typically important
in tungsten carbide articles, nickel's ability to alloy with
metals, and particularly chromium
[0019] In a preferred embodiment, the formulation of the starting
materials of the substrate by weight is about 22 Kg tungsten
carbide, 13.5 Kg titanium carbide, 10.5 Kg nickel, 3.5 Kg
molybdenum, 0.5 Kg chromium, and 5 Kg rubber binder. All of the
foregoing are combined as powders or shot and thoroughly mixed
together. As mentioned below, the rubber binder will vaporize
during manufacturing. Thus, the nickel will form about 21 percent
by weight of the finished jewelry article, the molybdenum will form
about 7 percent by weight of the finished article, and the chromium
will form about 1 percent by weight of the finished article.
Accordingly, total metal in the finished article will be about 29
percent by weight, in the preferred embodiment.
[0020] In one embodiment of manufacturing substrate 10 in which
improved jewelry article 1 is a ring, a rubber binder is combined
with the other components of substrate and poured into a metal mold
and pressed via hydraulic press for approximately 10 seconds. The
pressure applied can be between 160 Kg/cm.sup.2 to 210 Kg/cm.sup.2.
The amount of pressure applied varies directly with the size of the
ring being manufactured, such that the pressure applied to
manufacture a size 6 ring will be less than the pressure applied to
manufacture a size 13 ring.
[0021] The molded substrate is then heated from ambient temperature
to approximately 550 degrees Celsius. The temperature is held at
550 degrees Celsius for approximately 2 hours to allow rubber
binder to vaporize. The temperature is then steadily increased to a
target temperature of approximately 1400 degrees Celsius which is
reached at approximately 17 hours into the manufacturing process.
The temperature peak of 1400 degrees Celsius is below the melting
point of elemental nickel which is 1455 degrees Celsius. However,
combining nickel with the other components of the substrate is
believed to lower its melting point such that the nickel in the
substrate will melt at or below the temperature peak of the
manufacturing process, 1400 degrees Celsius. The manufacturing
process for the substrate is more thoroughly discussed in pending
U.S. patent application Ser. No. 12/904,349, which is hereby
incorporated by reference in its entirety.
[0022] Another advantageous property of nickel is that it readily
wets tungsten carbide, such that the tungsten carbide within the
substrate should become surrounded by nickel upon its melting. Due
to the melting of nickel and the wetting of tungsten carbide, the
nickel should be well distributed throughout the completed
substrate. This should make the nickel readily available for
binding with the coating 11. Similarly, molybdenum will be present
throughout the substrate via mixing prior to sintering.
[0023] In the development of the present invention, the desired
brilliant white finish was originally sought via the use of several
brilliant white metals. In one attempt, a substantially pure
rhodium coating was applied to the substrate. While a brilliant
white finish was achieved, the jewelry article formed therein did
not have the desired durability, and the coating spalled off
easily. In yet another attempt, a pure chromium coating was applied
to enhance durability. Chromium was selected because of its
hardness, 8.5 on the Mohs scale. However, while durability and
scratch resistance were achieved, the color of the coating was not
the desired brilliant white finish reminiscent of white gold,
platinum, and silver Finally, the present embodiment combining
chromium with a platinum group metal was selected. It achieves the
desired results of hardness, scratch resistance and brilliant white
finish.
[0024] In a preferred embodiment of the present invention, coating
11 is comprised predominantly of chromium and includes a platinum
group metal. The preferred coating 11 is approximately 97-99%
chromium, about 0.5-3% platinum, and about 0.01-0.03% each of
nickel, copper, and carbon. It is believed that any of the platinum
group metals can be used in place of the platinum in the coating to
achieve substantially similar results. Thus, it is believed that
ruthenium, rhodium, osmium, iridium, or palladium could be
substituted for platinum in coating 11.
[0025] It should be noted that the platinum group metals are
utilized primarily for color. They are particularly suitable where
a white coating is desired. Other metals may be utilized where a
different coating of a different color is desired.
[0026] In the manufacturing process, the chromium vapor solution is
mixed with a platinum group metal and deposited on the substrate
utilizing vapor deposition. There are two forms of vapor
deposition: physical vapor deposition and chemical vapor
deposition. The major physical vapor deposition methods are ion
plating, ion implantation, sputtering and laser surface alloying.
In a preferred embodiment, physical vapor deposition in the form of
sputtering deposition is used to apply coating to substrate to form
improved jewelry article 1. However, the other forms of physical
vapor deposition and chemical vapor deposition are believed to be
suitable for applying coating 11 to the substrate to form improved
jewelry article.
[0027] The basic premise of physical vapor deposition is depositing
a coating over an entire object or surface using dry vacuum
deposition methods. There are three basic elements to all reactive
physical vapor deposition processes: a method for deposition of the
metal, an active gas, and plasma bombardment of the coating to
ensure the metal deposits in dense, hard fashion. The preferred
process of physical vapor deposition, sputtering, is an etching
process which alters the physical properties of the surface of the
substrate. Sputtering can be used to deposit metals, alloys,
compounds, and dielectrics.
[0028] Sputtering involves a gas plasma discharge between a cathode
plating material and an anode substrate. The reactive gas ions,
which are positively charged, are attracted to and accelerated into
the cathode. The force of the impact knocks atoms off of the
cathode. Those atoms impact the anode and plate the substrate with
the coating.
[0029] Chemical vapor deposition is a subset of physical vapor
deposition, and the distinction between physical vapor deposition
and chemical vapor deposition continues to blur as new technologies
develop. Sputtering can also be done with chemical vapor
deposition, and the basic elements of chemical vapor deposition are
formation of a reactive gas mixture, mass transport of the reactant
gas through a boundary layer to the substrate, adsorption of the
reactants on the substrate, and reaction of the adsorbents to faun
the deposit.
[0030] As stated above, the preferred embodiment of the present
invention is an improved jewelry article 1 in which a coating 11 of
predominantly chromium is deposited on a substrate 10 of
predominantly tungsten carbide utilizing vapor deposition such that
a strong adhesion between the substrate 10 and coating 11 yields a
brilliant and preferably white finish that is scratch
resistant.
[0031] The disclosed method is believed to accomplish this result
in several ways. There is a high amount of metal and particularly
nickel in substrate 10 relative to other tungsten carbide jewelry.
Because the nickel is believed to thoroughly melt and spread
throughout substrate 10 during the manufacturing process, it is
available to alloy with coating 11. Thus, when the chromium and
platinum group coating is deposited onto substrate 10, there is a
substantial amount of metal and particularly nickel available with
which the coating components may interact. Chromium will readily
alloy with nickel and molybdenum. Thus, the presence of nickel and
molydenum will provide a superior bonding surface for coating 11
than would be provided by tungsten carbide. Accordingly, the
presence of the metals, and especially the nickel and molybdenum,
in the substrate will allow coating 11 to adhere more strongly to
substrate 10. Second, vapor deposition will provide a superior bond
between coating 11 and substrate 10 as compared to traditional
coating methods such as electroplating. Finally, chromium is quite
hard and, once securely fastened to the tungsten carbide substrate,
will resist scratching by most substances that would be regularly
encountered by a ring on the wearer's hands, even where the wearer
may be involved in heavy manual labor.
Example 1
[0032] To test the scratch resistance and adhesion of improved
jewelry article 1, a test was performed comparing improved jewelry
article 1 and a leading competitive product available in the
marketplace. The coating of the competitive white coated tungsten
carbide product was tested and is believed to have a composition
that is 54% gold, 25% rhodium, 16% chromium, and 5% iron. The
substrate of the competitive product is further believed to
comprise about 85% tungsten carbide by weight. Both improved
jewelry article 1 and the competing product were rings. A Grobet 0
file, approximately 1/4 inch wide by 3 inches long, was run along
the lap side of each ring one time. Scratches were observable with
the naked eye in the coating of the competitive ring. No scratches
were observable in the coating of the improved ring. After
observation with the unaided eye, the rings were studied under a
20.times. binocular microscope. Upon observation with the
microscope, no scratching was observed on the surface of the
improved ring. However, scratching on the surface of the
competitive ring was
* * * * *