U.S. patent application number 16/700057 was filed with the patent office on 2020-08-13 for powder metal with attached ceramic nanoparticles.
The applicant listed for this patent is United Technologies Corporation. Invention is credited to James T. Beals, Aaron T. Nardi, John A. Sharon, Ying She.
Application Number | 20200254518 16/700057 |
Document ID | 20200254518 / US20200254518 |
Family ID | 1000004810475 |
Filed Date | 2020-08-13 |
Patent Application | download [pdf] |
United States Patent
Application |
20200254518 |
Kind Code |
A1 |
She; Ying ; et al. |
August 13, 2020 |
POWDER METAL WITH ATTACHED CERAMIC NANOPARTICLES
Abstract
A powder material includes spherical metal particles and a
spaced-apart distribution of ceramic nanoparticles attached to the
surfaces of the particles.
Inventors: |
She; Ying; (East Hartford,
CT) ; Sharon; John A.; (Manchester, CT) ;
Beals; James T.; (West Hartford, CT) ; Nardi; Aaron
T.; (East Granby, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Technologies Corporation |
Farmington |
CT |
US |
|
|
Family ID: |
1000004810475 |
Appl. No.: |
16/700057 |
Filed: |
December 2, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15678260 |
Aug 16, 2017 |
10493524 |
|
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16700057 |
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14670623 |
Mar 27, 2015 |
9796019 |
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15678260 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 64/153 20170801;
B23K 15/0086 20130101; B23K 2103/14 20180801; B23K 15/0093
20130101; B23K 2103/02 20180801; B23K 2103/08 20180801; B22F 3/1055
20130101; B22F 2998/10 20130101; B23K 2103/10 20180801; B23K 26/342
20151001; Y02P 10/25 20151101; B22F 1/02 20130101; C22C 32/0015
20130101; B22F 1/0085 20130101; B23K 26/0006 20130101; B23K 2103/52
20180801 |
International
Class: |
B22F 1/02 20060101
B22F001/02; B29C 64/153 20060101 B29C064/153; B22F 3/105 20060101
B22F003/105; B23K 15/00 20060101 B23K015/00; B23K 26/00 20060101
B23K026/00; B23K 26/342 20060101 B23K026/342; B22F 1/00 20060101
B22F001/00 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with government support under
contract number W911NF-14-2-0011 awarded by the United States Army.
The government has certain rights in the invention.
Claims
1. A powder material comprising: spherical metal particles; and a
spaced-apart distribution of ceramic nanoparticles attached to the
surfaces of the particles.
2. The powder material as recited in claim 1, wherein the spherical
metal particles are selected from the group consisting of nickel,
chromium, and combinations thereof.
3. The powder material as recited in claim 1, wherein the ceramic
nanoparticles are selected from the group consisting of oxides,
nitrides, carbides, and combinations thereof, and the powder
material has a composition, by weight, of 0.1-5% of the ceramic
nanoparticles.
4. The powder material as recited in claim 1, wherein the ceramic
nanoparticles are oxide nanoparticles.
5. The powder material as recited in claim 1, wherein the ceramic
nanoparticles are zirconium oxide nanoparticles.
6. The powder material as recited in claim 1, wherein the spherical
metal particles are nickel-based particles and include
chromium.
7. The powder material as recited in claim 6, wherein the ceramic
nanoparticles are zirconium oxide nanoparticles.
8. The powder material as recited in claim 7, wherein the powder
material has a composition, by weight, of 0.1-5% of the ceramic
nanoparticles.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/678,260 filed Aug. 16, 2017, which is a continuation of
U.S. patent application Ser. No. 14/670,623 filed Mar. 27,
2015.
BACKGROUND
[0003] High performance alloys can be used in relatively severe
environments to provide enhanced mechanical properties, such as
high strength, creep resistance, and oxidation resistance. For
example, such alloys are dispersion-strengthened and include a
metallic matrix with a second phase of oxide, nitride, or carbide
dispersed uniformly throughout the matrix.
[0004] One technique for fabricating dispersion-strengthened alloys
is milling. Milling involves ball milling a metal feedstock powder
and reinforcement phase particles to incorporate the reinforcement
phase particles into the metal powder. The reinforcement phase
particles are generally not soluble in the base metal. Long times
are needed to achieve an appropriate dispersion and process control
agents are often needed to limit agglomeration. The agents must
later be removed, the resulting particles are irregularly-shaped,
and there is also difficulty in achieving consistency from
batch-to-batch.
SUMMARY
[0005] A powder material according to an example of the present
disclosure includes spherical metal particles and a spaced-apart
distribution of ceramic nanoparticles attached to the surfaces of
the particles.
[0006] In a further embodiment of any of the foregoing embodiments,
the spherical metal particles are selected from the group
consisting of nickel, chromium, and combinations thereof.
[0007] In a further embodiment of any of the foregoing embodiments,
the ceramic nanoparticles are selected from the group consisting of
oxides, nitrides, carbides, and combinations thereof, and the
powder material has a composition, by weight, of 0.1-5% of the
ceramic nanoparticles.
[0008] In a further embodiment of any of the foregoing embodiments,
the ceramic nanoparticles are oxide nanoparticles.
[0009] In a further embodiment of any of the foregoing embodiments,
the ceramic nanoparticles are zirconium oxide nanoparticles.
[0010] In a further embodiment of any of the foregoing embodiments,
the spherical metal particles are nickel-based particles and
include chromium.
[0011] In a further embodiment of any of the foregoing embodiments,
the ceramic nanoparticles are zirconium oxide nanoparticles.
[0012] In a further embodiment of any of the foregoing embodiments,
the powder material has a composition, by weight, of 0.1-5% of the
ceramic nanoparticles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The various features and advantages of the present
disclosure will become apparent to those skilled in the art from
the following detailed description. The drawings that accompany the
detailed description can be briefly described as follows.
[0014] FIG. 1 illustrates an example method for processing a powder
material.
[0015] FIG. 2 illustrates a low magnification micrograph of metal
particles that have ceramic nanoparticles attached on the
surfaces.
[0016] FIG. 3 illustrates a high magnification micrograph of the
surface of a metal particle with a spaced-apart distribution of
ceramic nanoparticles attached on the surface.
DETAILED DESCRIPTION
[0017] FIG. 1 illustrates an example method 20 for processing a
powder material. As will be described, the resulting powder
material produced using the method 20 has spherical metal particles
with a spaced-apart distribution of ceramic nanoparticles attached
on the surfaces of the spherical metal particles. The powder
material can readily be used in an additive fabrication process to
form an end-use article with dispersion-strengthening from the
ceramic nanoparticles.
[0018] Alloys with dispersed secondary reinforcement phases can be
fabricated by milling; however, this processing technique cannot
produce powder that can be used in additive fabrication processing.
Powders in additive fabrication processes are fed through an
additive manufacturing machine and deposited layer-by-layer in a
workspace where an energy beam can be used to selectively fuse
portions of the layers to form the end-use article. For proper
feeding and deposition of the layers, the powder typically has a
controlled particle size and a spherical powder particle shape that
permits easy flow through the equipment and uniform deposition of
the layers. Thus, although dispersion-strengthened alloys can be
fabricated by milling, the resulting particles are
irregularly-shaped and are thus not suited for reliable flow
through additive fabrication equipment. The example method 20
provides a spherical metal powder that has ceramic nanoparticles
attached to the surfaces thereof and which can be readily used in
additive fabrication processing.
[0019] As will be appreciated, the steps of the method 20 can be
used in combination with other processing steps. The example method
20 includes a cleaning step 22. In the cleaning step 22, the
surfaces of an initial powder material are prepared for attachment
of the ceramic nanoparticles. The initial powder material includes
spherical metal particles. For example, the spherical metal
particles have an average particle size of approximately 10-50
micrometers, which will typically be suitable for many additive
fabrication techniques. Of course, the powder may have a different
average size if needed by a particular additive fabrication
process.
[0020] The metal can be a pure metal or an alloy of several metals.
Although not limited, the metal can include nickel, chromium,
aluminum, titanium, iron, or combinations thereof, which may be
useful in aerospace articles.
[0021] The surfaces of the initial powder material may contain
oxides and/or foreign substances that can otherwise inhibit
attachment of the ceramic nanoparticles. For example, the initial
powder material can be cleaned using an acid, to etch away surface
oxides and foreign substances to provide a "fresh" metal surface
for attachment. The type and concentration of the acid can be
selected in accordance with the metal or metals to effectively etch
the surfaces without damaging the bulk particles.
[0022] The cleaned spherical metal particles are then subjected to
a coating step 24. In the coating step 24, the cleaned spherical
metal particles are coated with an organic bonding agent. The
organic bonding agent will later facilitate attachment of the
ceramic nanoparticles in the method 20.
[0023] As an example, the organic bonding agent includes a
surfactant that has polar end groups. The polar end groups
facilitate polar bonding with the surfaces of the spherical metal
particles and, later in the method 20, also polar bonding with the
ceramic nanoparticles. In this regard, the surfactant can be
selected in correspondence with the metal of the spherical metal
particles and the composition of the ceramic nanoparticles such
that polar end groups are selected for polar bonding with the metal
particles and also with the ceramic nanoparticles. For example, the
metal and the ceramic nanoparticles may have either a positive
polarity or a negative polarity, and the end groups are selected to
have a negative or positive polarity to form polar bonds with the
metal and with the ceramic nanoparticles.
[0024] In a further example, the surfactant includes dodecyl
sulfate, such as sodium dodecyl sulfate. For instance, the dodecyl
sulfate can be used with metal particles that include nickel,
chromium, or combinations thereof and with oxide ceramic
nanoparticles.
[0025] After the coating step 24, the coated spherical metal
particles are subjected to a mixing step 26. In the mixing step 26,
the coated spherical metal particles are mixed with a dispersion
that contains a carrier substance, such as a liquid-based medium,
and the ceramic nanoparticles. The ceramic nanoparticles can
include oxide particles, nitride particles, carbide particles, or
mixtures thereof. Zirconium oxide is one example of oxide
particles. Silicon carbide is one example of carbide particles.
Silicon nitride is one example of nitride particles.
[0026] The dispersion can include, but is not limited to, a colloid
that has a suspension of the ceramic nanoparticles in the carrier
substance. The mixture can be agitated or stirred for a period of
time to disperse the ceramic nanoparticles uniformly over the
surfaces having the organic bonding agent. The ceramic
nanoparticles attach by polar bonding to the polar end groups of
the organic bonding agent.
[0027] The spherical metal particles can then be rinsed in water.
The rinsing removes much of the excess dispersion and carrier
substance. Since the ceramic nanoparticles are relatively weakly
bonded by polar bonding (e.g., by van der Waals forces) to the
organic bonding agent, severe rinsing with large amounts of water
and agitation may undesirably wash away some of the bonded ceramic
nanoparticles. Thus, in one example, a controlled amount of
deionized water and, optionally, gentle stirring, can be used for
the rinse to limit wash-away loss of the bonded ceramic
nanoparticles.
[0028] For example, the controlled amount of water can be a
function of the concentration of the ceramic nanoparticles in the
dispersion, the concentration of the ceramic nanoparticles bonded
on the spherical metal particles, or both. Thus, only a limited
amount of water may be used to avoid washing away a substantial
amount of the bonded ceramic nanoparticles and to produce a desired
spaced-apart distribution of the ceramic nanoparticles. Given this
disclosure, those skilled in the art will be able to readily
determine appropriate rinsing through experimentation using
different amounts of water and observation of how much of the
ceramic nanoparticles are washed away.
[0029] Residual amounts of the carrier substance may be present on
the spherical metal particles, even after washing. At step 28, the
spherical metal particles are dried to remove any residual carrier
and to deposit the ceramic nanoparticles with the spaced-apart
distribution onto the organic bonding agent on the surfaces of the
spherical metal particles. For example, the spaced-apart
distribution of the ceramic nanoparticles is provided by the
selected concentration of the ceramic nanoparticles in the
dispersion that is used in the mixing step 26. If this
concentration is relatively high, the ceramic nanoparticles will be
deposited in a continuous coating rather than in the spaced-apart
distribution. The spaced-apart distribution is desired for
providing a dispersion of the ceramic nanoparticles in the end
article after additive fabrication, whereas a continuous coating
may result in agglomeration of the ceramic nanoparticles.
[0030] At step 30, the organic bonding agent is thermally removed
from the spherical metal particles to thereby attach the ceramic
nanoparticles to the surfaces of the spherical metal particles. For
example, the spherical metal particles are thermally treated in a
heating chamber at an elevated temperature for a determined period
of time to thermally remove the organic bonding agent. As can be
appreciated, the specific treatment temperature may be dependent
upon the selected organic bonding agent. However, in most
instances, organic materials will decompose and volatilize from the
powder at temperatures above approximately 550.degree. C. in an air
or an inert environment.
[0031] The resulting powder material includes the spherical metal
particles with the ceramic nanoparticles attached, by polar
bonding, to the surfaces thereof. In further examples, the
resulting powder material has a composition, by weight, of 0.1-5%
of the ceramic nanoparticles and a remainder of the metal. In a
further example, the spherical metal particles include nickel and
chromium, the ceramic nanoparticles are zirconium oxide, and the
resulting powder material has a composition, by weight, of 0.1-5%
of the zirconium oxide. The amount of ceramic nanoparticles on the
resulting powder material can be controlled by controlling the
concentration of the ceramic nanoparticles in step 26 and the
optional controlled rinsing. When the content of ceramic coating is
below a desirable amount in one single coating process described
above, the coating process can be repeated from the step of adding
the organic bonding to the step of thermal treatment until the
desirable content is achieved.
[0032] FIG. 2 shows a micrograph at low magnification of several
spherical metal particles 30 that have the ceramic nanoparticles 40
attached on the surfaces thereof. FIG. 3 shows a representative
surface of one of the spherical metal particles with the
spaced-apart distribution of the ceramic nanoparticles 40 (whitish
in color) attached on the surface thereof (dark color). As shown,
the ceramic nanoparticles 40 are discrete particles on the surface,
with a relatively uniform, spaced-apart distribution.
[0033] The following is a further, non-limiting example of the
method 20. Nanoparticles of zirconium oxide (ZrO.sub.2) were
attached onto surfaces of a spherical metal powder of composition
nickel-20 wt % chromium using sodium dodecyl sulfate as the
surfactant organic bonding agent. The zirconium oxide was provided
in a colloidal solution with nanoparticle sizes of approximately
five to ten nanometers. Approximately 30 grams of the Ni-20 wt. %
Cr powder with a mean particle size of approximately 40 micrometers
was etched in a beaker using approximately 14 ml of 18.5 wt %
hydrochloric acid for several minutes to create a fresh surface on
the powder. The etched powder was rinsed with deionized water
several times. Approximately 75 ml of 1 wt % sodium dodecyl sulfate
was added into the beaker with the etched powder and was stirred at
room temperature for several hours. The powder was then rinsed with
deionized water several times and dried in an oven at 120.degree.
C. for several hours. Approximately 21 grams of 20 wt % zirconium
oxide colloid solution was added into the beaker and the powder was
stirred at approximately 40.degree. C. for several hours, followed
by an aging process at room temperature for approximately one day.
The powder was then rinsed with a controlled amount of deionized
water, to avoid wash-away of the attached zirconium oxide
nanoparticles. The powder was then dried in an oven at
approximately 120.degree. C. for several hours with a ramp rate of
approximately 2.degree. C./min. The dried powder was then calcined
in a furnace at 550.degree. C. with a ramp rate of 2.degree. C./min
for several hours under ambient atmosphere. The zirconium oxide
nanoparticles were observed in a spaced-apart distribution on the
surface of the powder.
[0034] The powder material produced from the method 20 may be
further processed in another method that includes feeding the
powder through an additive processing machine to deposit multiple
layers of the powder material onto one another, and then using an
energy beam to thermally fuse selected portions of the layers to
one another with reference to data, such as computer-aided drawing
data, relating to a particular cross-section of an article being
formed. The energy beam melts or partially melts the metal such
that the selected portions of the layers of powder fuse together.
The ceramic nanoparticles may not melt, but disperse into the
melted or softened portions of the metal to thus provide a
relatively uniform dispersion of reinforcement through the formed
article.
[0035] Although a combination of features is shown in the
illustrated examples, not all of them need to be combined to
realize the benefits of various embodiments of this disclosure. In
other words, a system designed according to an embodiment of this
disclosure will not necessarily include all of the features shown
in any one of the Figures or all of the portions schematically
shown in the Figures. Moreover, selected features of one example
embodiment may be combined with selected features of other example
embodiments.
[0036] The preceding description is exemplary rather than limiting
in nature. Variations and modifications to the disclosed examples
may become apparent to those skilled in the art that do not
necessarily depart from this disclosure. The scope of legal
protection given to this disclosure can only be determined by
studying the following claims.
* * * * *