U.S. patent application number 12/904349 was filed with the patent office on 2012-04-19 for tungsten carbide ring composition.
This patent application is currently assigned to Stuller, Inc.. Invention is credited to Glenn A. Miller.
Application Number | 20120093675 12/904349 |
Document ID | / |
Family ID | 45934319 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120093675 |
Kind Code |
A1 |
Miller; Glenn A. |
April 19, 2012 |
TUNGSTEN CARBIDE RING COMPOSITION
Abstract
A powder mixture composition for forming a jewelry article is
described, comprising about 20-44% by weight tungsten carbide, and
one or more of titanium carbide, chromium, nickel, and molybdenum.
Methods of forming a jewelry article also are described, as are
formed jewelry articles.
Inventors: |
Miller; Glenn A.;
(Lafayette, LA) |
Assignee: |
Stuller, Inc.
|
Family ID: |
45934319 |
Appl. No.: |
12/904349 |
Filed: |
October 14, 2010 |
Current U.S.
Class: |
419/18 ; 419/66;
75/240; 75/252 |
Current CPC
Class: |
B22F 2998/00 20130101;
B22F 2998/00 20130101; C22C 29/06 20130101; B22F 1/0059 20130101;
A44C 27/003 20130101; C22C 29/10 20130101; C22C 29/08 20130101;
B22F 5/106 20130101 |
Class at
Publication: |
419/18 ; 75/252;
419/66; 75/240 |
International
Class: |
B22F 3/12 20060101
B22F003/12; C22C 28/00 20060101 C22C028/00; C22C 1/05 20060101
C22C001/05; B22F 1/00 20060101 B22F001/00; B22F 3/02 20060101
B22F003/02 |
Claims
1. A powder mixture composition for forming a jewelry article,
comprising: about 20-44% by weight tungsten carbide, and one or
more of: titanium carbide, chromium, nickel, and molybdenum.
2. The composition of claim 1, wherein the powder mixture comprises
about 35-44% by weight tungsten carbide.
3. The composition of claim 1, wherein the powder mixture comprises
about 18-27% by weight titanium carbide.
4. The composition of claim 1, wherein the powder mixture comprises
about 1-2% by weight chromium.
5. The composition of claim 1, wherein the powder mixture comprises
about 17-21% by weight nickel.
6. The composition of claim 1 wherein the powder mixture comprises
about 5-7% by weight molybdenum.
7. The composition of claim 1, comprising about 35-44% by weight
tungsten carbide; about 18-27% by weight titanium carbide; about
1-2% by weight chromium, about 17-21% by weight nickel, and about
5-7% by weight molybdenum.
8. The composition of claim 1, comprising about 44% by weight
tungsten carbide; about 27% by weight titanium carbide; about 1% by
weight chromium, about 21% by weight nickel, and about 7% by weight
molybdenum.
9. The composition of claim 1, further comprising a rubber
material.
10. The composition of claim 1, further comprising a rubber
material comprising styrene-butadiene-styrene (SBS).
11. A method of forming a jewelry article comprising: providing a
powder mixture composition comprising about 20-44% by weight
tungsten carbide and one or more of titanium carbide, chromium,
nickel, and molybdenum; optionally, placing the powder mixture
composition into a mold; and applying sufficient pressure and/or
temperature to the powder mixture composition to form a solid
jewelry article.
12. The method of claim 11, wherein the mold comprises a cavity
having an annular configuration.
13. The method of claim 11, further comprising the step of adding a
rubber material to the powder mixture composition.
14. A jewelry article formed according to the method of claim 11.
Description
BACKGROUND
[0001] The present invention generally relates to the field of
jewelry articles and specifically jewelry articles comprising
tungsten carbide.
SUMMARY
[0002] In accordance with some embodiments, there is provided a
powder mixture composition for forming a jewelry article,
comprising about 20-44% by weight tungsten carbide, and one or more
of titanium carbide, chromium, nickel, and molybdenum. In specific
embodiments, the powder mixture comprises about 35-44% by weight
tungsten carbide; about 18-27% by weight titanium carbide; about
1-2% by weight chromium, about 17-21% by weight nickel, and about
5-7% by weight molybdenum.
[0003] In accordance with other embodiments, there is provided a
method of forming a jewelry article comprising providing a powder
mixture composition comprising about 20-44% by weight tungsten
carbide and one or more of titanium carbide, chromium, nickel, and
molybdenum; optionally, placing the powder mixture composition into
a mold; and applying sufficient pressure and/or temperature to the
powder mixture composition to form a solid jewelry article. In
specific embodiments, the jewelry article is a ring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a flow diagram illustrating the steps in the
manufacture of a jewelry article, in accordance with one
embodiment.
[0005] FIGS. 2A-2B are images of jewelry article manufacture
equipment, a powder mixture and raw jewelry articles.
[0006] FIG. 3 illustrates a thermocycle for forming a jewelry
article from a powder mixture composition as described herein.
DETAILED DESCRIPTION
[0007] The present invention provides powder mixture compositions
for forming a jewelry article. The powder mixture composition
comprises tungsten carbide, and one or more of titanium carbide,
chromium, nickel, and molybdenum. In specific embodiments, the
powder mixture composition comprises about 20-44% by weight
tungsten carbide. The powder mixture compositions described herein
can be used to make jewelry articles with desirable (enhanced)
durability properties.
[0008] The present invention also provides methods of forming
jewelry articles, comprising (a) providing a powder mixture
comprising tungsten carbide, and one or more metallic and/or
ceramic component(s), (b) optionally, placing the powder mixture in
a mold and (c) applying sufficient pressure and/or temperature to
the powder mixture to form a solid jewelry article. Thus, the
jewelry article formed according to the present embodiments
comprises tungsten carbide, and one or more metallic and/or ceramic
components.
[0009] As used herein, the term "about" will be readily understood
by the skilled artisan based on the context and conventions in the
art. For example, "about" may encompass values .+-.1% of the stated
values. All percent ranges described herein are by weight and
include every individual value within each range.
Powder Mixture
[0010] In one embodiment, the powder mixture comprises tungsten
carbide, and one or more of titanium carbide, chromium, nickel, and
molybdenum. In specific embodiments, the powder mixture comprises
tungsten carbide, titanium carbide, chromium, nickel, and
molybdenum. For example, nickel can act as a binder.
[0011] The weight percentage range of each component in the mixture
may vary depending on the desired physical properties and/or
aesthetic appearance of, for example, a the jewelry article made
therefrom.
[0012] In general, the weight percent of tungsten carbide in the
powder mixture is about 20-44%. In some specific embodiments, the
weight percent of tungsten carbide in the powder mixture is about
35-44%.
[0013] With regard to other components, the powder mixture may
comprise, for example, one or more of: about 18-27% titanium
carbide; about 1-2% chromium; about 17-21% nickel; and about 5-7%
molybdenum.
[0014] In one specific illustrative embodiment, the powder mixture
comprises about 44% by weight tungsten carbide; about 27% by weight
titanium carbide; about 1% by weight chromium, about 21% by weight
nickel, and about 7% by weight molybdenum.
[0015] The powder mixture composition can be prepared by any means.
In one embodiment, the powder mixture is prepared by milling a
particle mixture of the components (e.g., tungsten carbide and one
or more of the other components mentioned above) for a sufficient
period of time to reduce the size of the mixture particles. In
another embodiment, the powder mixture is prepared by combining
components that are already in powder form (e.g., as fine
particles). In a further embodiment, in addition to milling, the
mixture is also subject to one or more steps of
sedimentation/separation, drying and sifting.
[0016] The particle size range in the powder mixture is
advantageously small enough to allow effective sintering of said
powder mixture. If needed, particle size may be reduced by running
a particle mixture through a sieve, to obtain smaller particle
sizes. For instance in a non-limiting example, a mixture is run
through one or more sieves with mesh hole diameter(s) less than
0.40 mm to obtain a powder mixture with an average particle size of
about 1-2 .mu.m.
[0017] In a non-limiting example, a mixture comprising tungsten
carbide, and one or more of titanium carbide, chromium, nickel, and
molybdenum is milled, followed by sedimentation/separation, drying
and sifting steps to form a powder mixture.
[0018] In another non-limiting example, a mixture of tungsten
carbide, and one or more of titanium carbide, chromium, nickel, and
molybdenum is subjected to (a) milling, (b)
sedimentation/separation, (c) drying, (d) sifting and again (e)
drying to form a powder mixture.
[0019] In one embodiment, the powder mixture also comprises at
least one rubber material. In one aspect, the rubber may assist in
binding the powder particles together. In a further aspect, the
rubber may assist in processing and shaping the powder mixture.
Thus, the amount of rubber added may vary depending on the
processing and shaping requirements. Examples of suitable rubbers
include, but are not limited to, latex rubbers, butadiene rubbers,
styrene butadiene rubbers, thermoplastic elastomers and melt
processible rubbers. Of course, a combination of different types of
rubbers may also be used. In some embodiments, the rubber material
comprises styrene-butadiene-styrene (SBS). However, other similar
polymeric materials such as styrene-isoprene-styrene may be equally
useful. Where the mixture processing step includes milling, the
rubber material may advantageously be added after the milling
step.
[0020] In one embodiment, the powder mixture also comprises
components which impart color to a jewelry article made therefrom.
For instance an amount of a nitride may be added to change the
color of the article.
[0021] In certain cases, the weight percent of tungsten carbide and
other components in the powder mixture may differ from that in a
raw jewelry article made therefrom. For instance, addition of other
components, such as SBS (styrene-butadiene-styrene) rubber or
coloring agent, may lower the weight percent of the powder mixture
components in the raw jewelry article. Still, in some embodiments,
the weight percent of the components in the powder mixture and
jewelry article maybe about the same, such as if no other
components are used, or if only minor amounts of other components
are used.
Forming A Jewelry Article
[0022] Once formed, the powder mixture composition may be formed
into a jewelry article, such as by exposing the powder mixture
composition to elevated temperatures and/or pressures to form a
jewelry article. For example, the powder mixture composition may be
placed in the cavity of a mold and subjected to elevated
temperature (optionally under a vacuum) and/or pressure to form a
raw jewelry article.
[0023] Any mold can be used. For example, the mold cavity may be
shaped according to any basic jewelry article design. In specific
embodiments, the mold cavity produces an annular shaped jewelry
article, such as for a ring. The formed raw jewelry article may
comprise one or more facets, grooves, or notches.
[0024] In a non-limiting example, the powder mixture is sintered in
a mold at a temperature of about 1400-1450.degree. C. In yet
another non-limiting example, the powder mixture is first heated at
about 550.degree. C. before sintering, such as to remove the rubber
contents (wax).
[0025] After molding, the raw jewelry article may be then subject
to further processing steps, such as attaching precious metals
pieces or gems to the article.
[0026] The flow diagram of FIG. 1 provides a non-limiting example
of manufacturing steps 100-118, for forming a jewelry article in
accordance with one embodiment.
[0027] In step 100, a mixture comprising, tungsten carbide (WC),
titanium carbide (TiC), chromium (Cr), nickel (Ni), and molybdenum
(Mo) is milled in ethanol for 72 hours. In step 102, the milled
mixture undergoes sedimentation/separation followed by a drying
step 104 at 90-100.degree. C., 1 atm for 2.5 hours. Following a
sifting step 106, an amount of SBS rubber is then added to the
powder mixture in step 108. This mixture is again sifted resulting
in a powder mixture having particles sizes in the range of about
1-2 .mu.m. The first and second sifting steps are carried out using
a mesh with 0.19 mm and 0.38 mm diameter holes, respectively. The
powder mixture is then dried in step 112 for about 1-1.5 hours and
shaped in consecutive molding 114 and sintering 116 steps.
[0028] The sintering step is carried out in a vacuum furnace by
first heating the raw article (to remove the rubber) at 550.degree.
C. for about 2 hours, then heating at 1400-1450.degree. C. for
about half an hour (such as 30-40 minutes), followed by cooling
over a period of 10-14 hours to 30.degree. C. or room temperature .
The raw jewelry article is then obtained in step 118 for additional
processing, as desired or required.
[0029] FIGS. 2A-B depict manufacturing equipment connected with the
steps shown in FIG. 1. Specifically, FIG. 2A shows a milling
machine 202, sedimentation/separation equipment 204, drying
equipment 206 and 212 and adding/sifting apparatus 208 and 210.
FIG. 2B shows a molding unit 216, a vacuum furnace 218, a powder
mixture 214 as well as raw jewelry articles 220.
[0030] The manufacturing process described shows a 100 kg/day
production capacity for powder mixture production. Also, the
molding process has the capacity to handle 2500 pieces/mold in one
day. Finally, the production of the raw jewelry article is about
5000 pcs/day.
[0031] FIG. 3 illustrates a non-limiting thermocycle for forming a
jewelry article from a powder mixture composition as described
herein. As shown, a powder mixture composition as described herein
is placed in a mold in a vacuum furnace and the furnace temperature
is raised slowly (e.g., over 16 hours) to a temperature of about
1400.degree. C., including a holding period (e.g., about 2 hours)
at 550.degree. C. After a holding period (e.g., about 30-40
minutes) at 1400.degree. C., the furnace temperature is slowly
reduced (e.g., over 14 hours).
[0032] Although the foregoing refers to particular embodiments, it
will be understood that the present invention is not so limited. It
will occur to those of ordinary skill in the art that various
modifications may be made to the disclosed embodiments and that
such modifications are intended to be within the scope of the
present invention.
* * * * *