U.S. patent application number 14/563257 was filed with the patent office on 2016-06-09 for methods of forming an article using electrophoretic deposition, and related article.
The applicant listed for this patent is General Electric Company. Invention is credited to Nicholas Edward Antolino, Don Mark Lipkin, Stephen Francis Rutkowski.
Application Number | 20160160374 14/563257 |
Document ID | / |
Family ID | 54783365 |
Filed Date | 2016-06-09 |
United States Patent
Application |
20160160374 |
Kind Code |
A1 |
Antolino; Nicholas Edward ;
et al. |
June 9, 2016 |
METHODS OF FORMING AN ARTICLE USING ELECTROPHORETIC DEPOSITION, AND
RELATED ARTICLE
Abstract
In one example of the present technology, a method for forming
an article includes disposing an electrically conductive coating on
a substrate. The method further includes disposing a layer stack on
the electrically conductive coating by (i) disposing a first
barrier coating by electrophoretic deposition; (ii) heat treating
the first barrier coating; (iii) disposing an electrically
conductive layer on the first barrier coating; and (iv) optionally
repeating steps (i) to (iii). The method further includes disposing
a second barrier coating on an outermost electrically conductive
layer in the layer stack by electrophoretic deposition; and heat
treating the second barrier coating.
Inventors: |
Antolino; Nicholas Edward;
(Schenectady, NY) ; Lipkin; Don Mark; (Niskayuna,
NY) ; Rutkowski; Stephen Francis; (Duanesburg,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
54783365 |
Appl. No.: |
14/563257 |
Filed: |
December 8, 2014 |
Current U.S.
Class: |
428/448 ;
204/487 |
Current CPC
Class: |
C04B 41/52 20130101;
C04B 41/009 20130101; C23C 18/165 20130101; F01D 5/288 20130101;
C04B 41/52 20130101; C04B 41/52 20130101; C04B 41/89 20130101; C04B
41/5059 20130101; C04B 41/522 20130101; C04B 41/48 20130101; C04B
41/4564 20130101; C04B 41/5024 20130101; C04B 41/5116 20130101;
C04B 41/522 20130101; C04B 2103/0021 20130101; C04B 41/5071
20130101; C04B 41/4564 20130101; C04B 2103/0021 20130101; C04B
35/58085 20130101; C04B 41/522 20130101; C04B 35/565 20130101; C04B
41/4541 20130101; C04B 41/4539 20130101; C04B 41/5024 20130101;
C04B 41/526 20130101; C04B 41/5096 20130101; C04B 41/5116 20130101;
C04B 35/806 20130101; C04B 41/4549 20130101; C04B 41/522 20130101;
C04B 41/0072 20130101; C04B 35/584 20130101; C04B 41/0072 20130101;
F05D 2230/31 20130101; C04B 35/806 20130101; C04B 41/52 20130101;
C04B 41/52 20130101; C04B 41/009 20130101; C04B 41/52 20130101;
C04B 41/52 20130101; C04B 41/52 20130101; C04B 41/52 20130101; C25D
13/02 20130101; C04B 41/009 20130101; C04B 41/009 20130101; C25D
13/22 20130101; C25D 13/12 20130101 |
International
Class: |
C25D 13/22 20060101
C25D013/22; C25D 13/12 20060101 C25D013/12; C25D 13/02 20060101
C25D013/02 |
Claims
1. A method for forming an article, comprising: (a) disposing an
electrically conductive coating on a substrate; (b) disposing a
layer stack on the electrically conductive coating by: (i)
disposing a first barrier coating by electrophoretic deposition;
(ii) heat treating the first barrier coating; (iii) disposing an
electrically conductive layer on the first barrier coating; and
(iv) optionally repeating steps (i) to (iii); (c) disposing a
second barrier coating on an outermost electrically conductive
layer in the layer stack by electrophoretic deposition; and (d)
heat treating the second barrier coating.
2. The method of claim 1, wherein the first barrier coating and the
second barrier coating undergo at least partial densification
during the heat treatment steps.
3. The method of claim 1, wherein the electrically conductive layer
is disposed by electroless plating, spraying, dip coating, physical
vapor deposition, chemical vapor deposition, or combinations
thereof.
4. The method of claim 1, wherein the electrically conductive layer
comprises a metal, an intermetallic, a metalloid, carbon, a
conductive polymer, or combinations thereof.
5. The method of claim 4, wherein the electrically conductive layer
comprises gold, silver, nickel, a conductive polymer, carbon,
palladium, platinum, copper, iron, cobalt, boron, or combinations
thereof.
6. The method of claim 4, wherein the electrically conductive layer
comprises electroless-plated gold platinum, palladium, copper,
nickel, cobalt, iron, boron, or combinations thereof.
7. The method of claim 1, wherein the first barrier coating
comprises a rare earth silicate.
8. The method of claim 7, wherein the first barrier coating
comprises a rare earth disilicate selected from the group
consisting of ytterbium disilicate, yttrium disilicate, and
combinations thereof.
9. The method of claim 1, wherein the second barrier coating
comprises a rare earth silicate.
10. The method of claim 9, wherein the second barrier coating
comprises a rare earth monosilicate selected from the group
consisting of yttrium monosilicate, ytterbium monosilicate, and
combinations thereof.
11. The method of claim 1, wherein the electrically conductive
coating disposed on the substrate comprises silicon, metal
silicide, silicon carbide, or combinations thereof.
12. The method of claim 1, wherein the electrically conductive
coating disposed on the substrate further functions as a bond
coating between the substrate and the first barrier coating.
13. An article formed by the method of claim 1.
14. A turbine engine component comprising the article of claim
13.
15. A method for forming an article, comprising: (a) disposing an
electrically conductive coating on a substrate; (b) disposing a
layer stack on the electrically conductive coating by: (i)
disposing a first barrier coating by electrophoretic deposition,
wherein the first barrier coating comprises a rare earth
disilicate; (ii) heat treating the first barrier coating; (iii)
disposing an electrically conductive layer on the first barrier
coating; and (iv) optionally repeating steps (i) to (iii); (c)
disposing a second barrier coating on an outermost electrically
conductive layer in the layer stack by electrophoretic deposition,
wherein the second barrier coating comprises a rare earth
monosilicate; and (d) heat treating the second barrier coating.
16. The method of claim 15, wherein the first barrier coating and
the second barrier coating undergo at least partial densification
during the heat treatment steps.
17. The method of claim 15, wherein the electrically conductive
layer is disposed by electroless plating, spraying, dip coating,
physical vapor deposition, chemical vapor deposition, or
combinations thereof.
18. The method of claim 15, wherein the electrically conductive
layer comprises a metal, an intermetallic, a metalloid, carbon, a
conductive polymer, or combinations thereof.
19. The method of claim 18, wherein the electrically conductive
layer comprises gold, silver, nickel, a conductive polymer, carbon,
palladium, platinum, copper, iron, cobalt, boron, or combinations
thereof.
20. The method of claim 15, wherein the electrically conductive
coating comprises silicon, metal silicide, silicon carbide, or
combinations thereof.
Description
BACKGROUND
[0001] The present technology generally relates to methods of
forming an article using electrophoretic deposition. More
particularly, the present technology relates to methods of forming
an article by disposing one or more barrier layers using
electrophoretic deposition.
[0002] As the push for higher efficiency has driven higher
operating temperatures for gas turbine engines, it becomes
desirable to correspondingly improve the high temperature
durability of the components of the engine. Monolithic ceramics,
ceramic matrix composites (CMCs), and refractory metal silicides
offer increased temperature capability over iron, nickel and
cobalt-based superalloys.
[0003] CMCs are a class of materials that include a ceramic
reinforcing material surrounded by a ceramic matrix phase. Such
materials, along with certain monolithic ceramics (i.e. ceramic
materials without a reinforcing material), provide a desirable
combination of high-temperature strength and low density compared
to metallic superalloys.
[0004] CMCs, monolithic ceramic components, and refractory metal
silicides may be coated with environmental barrier coatings (EBCs)
to protect them from the harsh environment of high temperature
engine sections. EBCs can protect the substrate from heat and
corrosive gases in the combustion environment. For example, EBCs
can protect silicon-containing substrates from volatilization in
high temperature steam. However, the standard, industrial coating
processes currently used to apply the EBCs (such as plasma spray)
may have some drawbacks. One such drawback is the difficulty in
applying hermetic coatings onto components with non-line-of-sight
features and regions of high convex and concave curvature.
[0005] Accordingly, there remains a need for improved methods for
depositing environmental barrier coatings. Further there is a need
for improved articles incorporating the coatings deposited using
these methods.
BRIEF DESCRIPTION
[0006] In one example of the present technology, a method for
forming an article includes disposing an electrically conductive
coating on a substrate. The method further includes disposing a
layer stack on the electrically conductive coating by (i) disposing
a first barrier coating by electrophoretic deposition; (ii) heat
treating the first barrier coating; (iii) disposing an electrically
conductive layer on the first barrier coating; and (iv) optionally
repeating steps (i) to (iii). The method further includes disposing
a second barrier coating on an outermost electrically conductive
layer in the layer stack by electrophoretic deposition; and heat
treating the second barrier coating.
[0007] In another example of the present technology, an article
formed by the method described herein is presented.
[0008] In another example of the present technology, a method for
forming an article includes disposing an electrically conductive
coating on a substrate. The method further includes disposing a
layer stack on the electrically conductive coating by (i) disposing
a first barrier coating by electrophoretic deposition, wherein the
first barrier coating includes a rare earth disilicate; (ii) heat
treating the first barrier coating; (iii) disposing an electrically
conductive layer on the first barrier coating; and (iv) optionally
repeating steps (i) to (iii). The method further includes disposing
a second barrier coating on an outermost electrically conductive
layer in the layer stack by electrophoretic deposition, wherein the
second barrier coating includes a rare earth monosilicate; and heat
treating the second barrier coating.
DRAWINGS
[0009] These and other features, aspects, and advantages of the
present technology will become better understood when the following
detailed description is read with reference to the accompanying
drawings, wherein:
[0010] FIG. 1a is an illustration of a method step according to an
example of the present technology;
[0011] FIG. 1b is an illustration of a method step according to an
example of the present technology;
[0012] FIG. 1c is an illustration of a method step according to an
example of the present technology; and
[0013] FIG. 2 is an illustration of a method according to an
example of the present technology.
DETAILED DESCRIPTION
[0014] In the following specification and the claims, which follow,
reference will be made to a number of terms, which shall be defined
to have the following meanings. The singular forms "a", "an" and
"the" include plural referents unless the context clearly dictates
otherwise. "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0015] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about", and
"substantially" is not to be limited to the precise value
specified. In some instances, the approximating language may
correspond to the precision of an instrument for measuring the
value. Similarly, "free" may be used in combination with a term,
and may include an insubstantial number, or trace amounts, while
still being considered free of the modified term. Here and
throughout the specification and claims, range limitations may be
combined and/or interchanged, such ranges are identified and
include all the sub-ranges contained therein unless context or
language indicates otherwise.
[0016] As used herein, the term "layer" refers to a material
disposed on at least a portion of an underlying surface in a
continuous or discontinuous manner. Further, the term "layer" does
not necessarily mean a uniform thickness of the disposed
material.
[0017] As used herein, the term "coating" refers to a material
disposed on at least a portion of an underlying surface in a
continuous or discontinuous manner. Further, the term "coating"
does not necessarily mean a uniform thickness of the disposed
material, and the disposed material. The term "coating" may refer
to a single layer of the coating material or may refer to a
plurality of layers of the coating material. The coating material
may be the same or different in the plurality of layers.
[0018] As used herein, the term "disposed on" refers to layers or
coatings disposed directly in contact with each other or indirectly
by having intervening layers there between, unless otherwise
specifically indicated. The term "adjacent" as used herein means
that at least a portion of the two layers or coatings are disposed
contiguously and are in direct contact with each other.
[0019] FIGS. 1 and 2 illustrate a method 10 in accordance with an
example of the present technology. As illustrated in FIGS. 1a and
2, the method 10 includes, at step 11, disposing an electrically
conductive coating 120 on a substrate 110. The method (FIGS. 1b and
2) further includes, at step 12, forming a layer stack 150 on the
electrically conductive coating 120 by: (i) disposing a first
barrier coating 130 by electrophoretic deposition; (ii) heat
treating the first barrier coating 130; (ii) disposing an
electrically conductive layer 140 on the first barrier coating; and
optionally repeating steps (i) to (iii). The method further
includes (FIGS. 1c and 2), at step 13, disposing a second barrier
coating 160 on an outermost electrically conductive layer 140 in
the layer stack 150 by electrophoretic deposition. The method
further includes at step 14, heat treating the second barrier
coating 160.
[0020] The substrate 110 may include a silicon-containing material.
Non-limiting examples of suitable silicon-containing materials
include silicon carbide, silicon nitride, silicide (for example, a
refractory metal or transition metal silicide), elemental silicon,
or combinations thereof. The silicon containing material may be
present in the substrate as one or both of the matrix and a second
phase.
[0021] Further, examples of substrate 110 include ceramic matrix
composites (CMCs) or monolithic ceramics. As used herein, the term
"monolithic ceramics" refers to ceramic materials without
reinforcing materials, for example, fibers or whiskers. As used
herein, the term "CMCs" refers to materials including ceramic
fibers incorporated in a ceramic matrix, thus forming a ceramic
fiber reinforced ceramic. Suitable CMCs include silicon-containing
CMCs and oxide-based CMCs, such as oxide-oxide CMCs.
[0022] In silicon-containing CMCs, one or both of the matrix and
the reinforcing fiber may include a silicon-containing material,
such as silicon, silicon carbide, silicon nitride, silicon
oxycarbide, silicon oxynitride, or combinations thereof.
Non-limiting examples of suitable CMCs include CMCs including
silicon carbide matrix and silicon carbide fiber; CMCs including
silicon nitride matrix and silicon carbide fiber; and CMCs
including silicon carbide/silicon nitride matrix mixture and
silicon carbide fiber.
[0023] In oxide-oxide CMCs, one or both of the matrix and
reinforcing fiber may include an oxide, such as aluminum oxide
(Al.sub.2O.sub.3), silicon dioxide (SiO.sub.2), aluminosilicate, or
combinations thereof. Aluminosilicates may include crystalline
materials such as mullite (3Al.sub.2O.sub.3.2SiO.sub.2) as well as
glassy aluminosilicates.
[0024] The electrically conductive coating 120 may include
elemental silicon, metal silicide, silicon carbide, or combinations
thereof. Non-limiting examples of suitable metal silicides include
rare earth silicides, chromium silicide (e.g. CrSi.sub.2), niobium
silicide (e.g. NbSi.sub.2, Nb.sub.5Si.sub.3), molybdenum silicide
(e.g. MoSi.sub.2, Mo.sub.5Si.sub.3), tantalum silicide (e.g.
TaSi.sub.2), titanium silicide (e.g. TiSi.sub.2), tungsten silicide
(e.g. WSi.sub.2, W.sub.5Si.sub.3), zirconium silicide (e.g.
ZrSi.sub.2), hafnium silicide (e.g. HfSi.sub.2), or combinations
thereof. In one example, the electrically conductive coating 120
includes elemental silicon.
[0025] The thickness of the electrically conductive coating 120 may
be in a range from about 10 microns to about 150 microns. The
electrically conductive coating 120 may be disposed on the
substrate 110 by plasma spray, combustion thermal spray, chemical
vapor deposition, electron beam physical vapor deposition, molten
silicon dipping, sputtering, powder-based application and
sintering, and other conventional application processes known to
those skilled in the art.
[0026] The electrically conductive properties of the coating 120
allows for deposition of the first barrier coating 130 by
electrophoretic deposition. In some examples of the present
technology, the electrically conductive coating 120 may further
function as a bond coating between the substrate and the overlying
first barrier coating 130. The term "bond coating" as used herein
refers to a coating that provides for improved adhesion between a
substrate and an overlying coating. In some such instances, the
electrically conductive coating 120 may also serve as an oxidation
barrier to prevent oxidation of the substrate 110. In some other
examples of the present technology, the method may further include
a step of disposing an additional bond coating (not shown in
Figures) on the substrate prior to the step of disposing the
electrically conductive coating.
[0027] As noted earlier, the method further includes forming a
layer stack 150. In some instances, the layer stack 150 may include
a single first barrier coating 130 and a single electrically
conductive layer 140, as illustrated in FIG. 1. In such instances,
the first barrier coating 130 is disposed on the electrically
conductive coating 120 by electrophoretic deposition followed by
heat treatment and deposition of the electrically conductive layer
140 to form a layer stack 150. The second barrier coating 160 is
then disposed on the electrically conductive layer 140 by
electrophoretic deposition. As mentioned earlier, the method
further includes heat treating the second barrier coating 160. In
some instances, the method further includes at least partial
densification of the first barrier coating and the second barrier
coating during the heat treatment steps.
[0028] Alternatively, the layer stack 150 may include a plurality
of first barrier coatings 130 and a plurality of electrically
conductive layers 140. In such instances, the plurality of first
barrier coatings 130 and the plurality of electrically conductive
layers 140 are disposed in an alternating manner (not shown in
Figures). In such instances, the method includes first disposing a
first barrier coating 130 on the electrically conductive coating
120 by electrophoretic deposition, heat treating the first barrier
coating 130, disposing an electrically conductive layer 140 on the
first barrier coating 130, disposing a first barrier coating 130 on
the electrically conductive layer 140 by electrophoretic
deposition, heat treating the first barrier coating 130, disposing
an electrically conductive layer 140 on the first barrier coating
130 by electrophoretic deposition, and so on to form the layer
stack 150.
[0029] As noted, the first barrier coating 130 is deposited by
electrophoretic disposition. Accordingly, in instances requiring a
plurality of first barrier coatings 130 (for example, to build
thickness while maintaining coating hermeticity and uniformity),
application of an electrically conductive layer 140 prior to the
deposition of the first barrier coating 130 facilitates
electrophoretic deposition of the barrier coating material. Without
the electrically conductive layers 140, electrophoretic deposition
of successive first barrier coatings 130 may not be possible as the
first barrier coatings 130 are inherently electrically
insulative.
[0030] The term "barrier coating" as used herein refers to a
coating that may function as an environmental barrier coating, a
thermal barrier coating, a chemical barrier coating, or
combinations thereof. A barrier coating may thus perform one or
more of the following functions: inhibiting formation of volatile
silicon hydroxide (for example, Si(OH).sub.4) products; inhibiting
water vapor ingress to the oxidizing surface; inhibiting the
ingress of chemical contaminants to the substrate; and reducing the
amount of heat flux into the substrate. A barrier coating may
further exhibit one or more of the following properties: a
coefficient of thermal expansion (CTE) compatible with the
Si-containing substrate material, low permeability for oxidants,
low thermal conductivity, low silica chemical activity, and
chemical compatibility with the underlying Si-containing material
and thermally grown silica. The barrier coating is typically an
electrically insulating material.
[0031] The first barrier coating 130 may include a material
suitable for use on ceramic substrate components found in high
temperature environments (e.g., operating temperatures greater than
1140.degree. C.), such as those present in gas turbine engines. In
some embodiments, the first barrier coating 130 includes a rare
earth silicate. In some embodiments, the first barrier coating 130
includes a rare earth disilicate, a rare earth monosilicate, or
combinations thereof. Non-limiting examples of suitable rare earth
metals include scandium, yttrium, lanthanum, cerium, gadolinium,
praseodymium, neodymium, promethium, samarium, europium, terbium,
dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or
combinations thereof.
[0032] In some embodiments, the first barrier coating 130 includes
a rare earth disilicate, wherein the rare earth elements comprise
ytterbium, yttrium, or combinations thereof. The first barrier
coating 130 may also include one or more additional constituents
such as dopants, sintering aids and the like. For example, the
first barrier coating 130 may further include rare earth
monosilicates, wherein the rare earth elements comprise ytterbium,
yttrium, or combinations thereof, as well as oxides of iron,
aluminum, silicon or boron.
[0033] Each first barrier coating 130 may have a thickness in a
range from about 5 microns to about 200 microns. In instances
wherein the method includes disposing a plurality of first barrier
coatings 130, each first barrier coating 130 in the layer stack 150
may have the same composition as the other first barrier coatings
130, or alternately may have a different composition. Further, the
thickness of the first barrier coatings 130 in the layer stack 150
may be the same or different.
[0034] As noted earlier, the electrically conductive layer 140 in
the layer stack 150 allow for deposition of the subsequent barrier
coating (first barrier coating 130 or second barrier coating 160)
by electrophoretic deposition. The electrically conductive layer
140 may include a material and a thickness capable of providing the
desired conductive properties without significantly compromising
the functionality or properties of the first barrier coating 130
and the second barrier coating 160.
[0035] The electrically conductive layer 140 may include a metal,
an intermetallic, a metalloid, carbon, a conductive polymer, or
combinations thereof. In some instances, the electrically
conductive layer 140 includes gold, silver, nickel, a conductive
polymer, carbon, palladium, platinum, copper, iron, cobalt, boron,
or combinations thereof.
[0036] The electrically conductive layer may include nanoparticles
of an electrically conductive material in some instances. The
particle size may be in a range from 1 nanometer to about 10
nanometers. The nanoparticles may be deposited on the first barrier
coating 130 in a powder form or as a paste.
[0037] Each electrically conductive layer 140 may have a thickness
in a range from about 10 nanometers to about 5 microns. In
instances wherein the method includes disposing a plurality of
electrically conductive layers 140, each electrically conductive
layer 140 in the layer stack 150 may have the same composition as
the other electrically conductive layer 140, or alternately may
have a different composition. Further, the thickness of the
electrically conductive layers 140 in the layer stack 150 may be
the same or different. The electrically conductive layer may be
disposed by electroless (auto-catalytic) plating, spraying, dip
coating or combinations thereof.
[0038] The method further includes disposing a second barrier
coating 160, as illustrated in FIGS. 1 and 2. The second barrier
coating 160 may include a rare earth silicate. The second barrier
coating 160 may include a rare earth disilicate, a rare earth
monosilicate, or combinations thereof. Non-limiting examples of
suitable rare earth metals include scandium, yttrium, lanthanum,
cerium, gadolinium, praseodymium, neodymium, promethium, samarium,
europium, terbium, dysprosium, holmium, erbium, thulium, ytterbium,
lutetium, or combinations thereof.
[0039] In some instances, the second barrier coating 160 includes a
rare earth monosilicate selected from the group consisting of
yttrium monosilicate, ytterbium monosilicate, and combinations
thereof. The second bather coating 160 may also include one or more
additional constituents such as dopants, sintering aids and the
like. For example, the second barrier coating 160 may further
include rare earth disilicates, wherein the rare earth elements
comprise ytterbium, yttrium, or combinations thereof, as well as
oxides of iron, aluminum, silicon or boron. The second barrier
coating 160 may also have a thickness in a range from about 5
microns to about 300 microns.
[0040] As mentioned previously, the second bather coating 160 is
deposited on the outermost electrically conductive layer 140 in the
layer stack 150 by electrophoretic deposition. The method further
includes heat treating the second barrier coating.
[0041] Some of the example methods in accordance with the present
technology allow for fabrication of articles by depositing one or
more layers by electrophoretic deposition. As noted previously, a
first barrier coating is disposed over an electrically conductive
coating and heat treated to at least partially densify it.
Optionally, a thin electrically conductive layer is disposed over
the underlying first barrier coating, allowing for deposition of a
subsequent first barrier coating by electrophoretic deposition.
This sequence is optionally repeated to build up a stack of first
barrier layers. Further, disposing an outermost thin electrically
conductive layer on the layer stack allows for deposition of the
second barrier coating by electrophoretic deposition.
[0042] An article formed by the method described herein is also
presented. The present technology is generally applicable to
components that operate within environments characterized by high
temperatures, thermal cycling, thermal and mechanical stresses, and
oxidation. Examples of such components include high and low
pressure turbine vanes (nozzles) and blades (buckets), shrouds,
combustor components (e.g., liners), heat shields, augmentor
hardware, and other hot section components of turbine engines,
though the technology has application to other components. A
turbine engine component including the article as described herein
is also presented.
EXAMPLES
[0043] The following examples illustrate methods and embodiments in
accordance with the present technology.
Example 1
[0044] A silicon coated ceramic matrix composite was provided such
that its surface was electrically conductive. A layer of ytterbium
disilicate was deposited by electrophoretic deposition from a bath
consisting of 28 percent by mass ytterbium disilicate, 0.25 percent
by mass iron (IIM) oxide, 0.05 percent by mass aluminum oxide, 0.05
percent by mass polyethylenimine, and 71.65 percent by mass ethanol
using a voltage of 60 volts at 2 cm standoff for 15 seconds. The
coating was air dried and heat treated in air at 1345 degrees
Celsius for 10 hours. The coating was then placed into a
commercially available electroless gold bath (angelgilding.com) for
40 minutes according to the manufacturer's instructions. After
drying, a layer of yttrium monosilicate was deposited by
electrophoretic deposition from a bath consisting of 22.72 percent
by mass yttrium monosilicate, 0.67 percent by mass iron (IIM)
oxide, 0.05 percent by mass polyethylenimine, and 76.56 percent by
mass ethanol using a voltage of 30 volts at 1.7 cm standoff for 10
seconds. The coating was air dried and heat treated in air at 1345
degrees Celsius for 10 hours.
Example 2
[0045] A silicon-coated ceramic matrix composite was provided such
that its surface was electrically conductive. A layer of ytterbium
disilicate was deposited by electrophoretic deposition from a bath
consisting of 28 percent by mass ytterbium disilicate, 0.25 percent
by mass iron (IIM) oxide, 0.05 percent by mass aluminum oxide, 0.05
percent by mass polyethylenimine, and 71.65 percent by mass ethanol
using a voltage of 60 volts at 2 cm standoff for 15 seconds. The
coating was air dried and heat treated in air at 1345 degrees
Celsius for 10 hours. A fine aerosol of silver nanoparticles
(Harima NPS-J Nano Paste.RTM.) was applied to the coating and heat
treated at 220 degrees Celsius in air for 1 hour. A second layer of
ytterbium disilicate was deposited by electrophoretic deposition
from a bath consisting of 28 percent by mass ytterbium disilicate,
0.25 percent by mass iron (IIM) oxide, 0.05 percent by mass
aluminum oxide, 0.05 percent by mass polyethylenimine, and 71.65
percent by mass ethanol using a voltage of 60 volts at 2 cm
standoff for 15 seconds. The coating was air dried and heat treated
in air at 1345 degrees Celsius for 10 hours. Then, another layer of
fine aerosol of silver nanoparticles (Harima NPS-J Nano Paste.RTM.)
was applied to the coating and heat treated at 220 degrees Celsius
in air for 1 hour. Finally, a layer of yttrium monosilicate was
deposited by electrophoretic deposition from a bath consisting of
22.72 percent by mass yttrium monosilicate, 0.67 percent by mass
iron (IIM) oxide, 0.05 percent by mass polyethylenimine, and 76.56
percent by mass ethanol using a voltage of 30 volts at 1.7 cm
standoff for 10 seconds. The coating was air dried and heat treated
in air at 1345 degrees Celsius for 10 hours.
Example 3
[0046] A silicon-coated ceramic matrix composite was provided such
that its surface is electrically conductive. A layer of ytterbium
disilicate was deposited by electrophoretic deposition from a bath
consisting of 28 percent by mass ytterbium disilicate, 0.25 percent
by mass iron (II,II) oxide, 0.05 percent by mass aluminum oxide,
0.05 percent by mass polyethylenimine, and 71.65 percent by mass
ethanol using a voltage of 60 volts at 2 cm standoff for 15
seconds. The coating was air dried and heat treated in air at 1345
degrees Celsius for 10 hours. The coating was then dipped into a
bath of Plexcore.RTM. OC RG-1110 conductive polymer and withdrawn
to leave a thin coating. The conductive coating was cured at 150
degrees Celsius in air for 1 hr. A layer of yttrium monosilicate
was deposited by electrophoretic deposition from a bath consisting
of 22.72 percent by mass yttrium monosilicate, 0.67 percent by mass
iron (II,II) oxide, 0.05 percent by mass polyethylenimine, 76.56
percent by mass ethanol using a voltage of 30 volts at 1.7 cm
standoff for 10 seconds. The coating was air dried and heat treated
in air at 1345 degrees Celsius for 10 hours.
[0047] The foregoing examples are merely illustrative, serving to
exemplify only some of the features of the present technology. The
appended claims are intended to claim the inventions as broadly as
permitted and the examples herein presented are illustrative only.
Accordingly, the appended claims are not to be limited by the
choice of examples utilized to illustrate features of the present
technology. As used in the claims, the word "comprises" and its
grammatical variants logically also subtend and include phrases of
varying and differing extent such as for example, but not limited
thereto, "consisting essentially of" and "consisting of." Where
necessary, ranges have been supplied; those ranges are inclusive of
all sub-ranges there between. It is to be expected that variations
in these ranges will suggest themselves to a practitioner having
ordinary skill in the art and where not already dedicated to the
public, those variations should where possible be construed to be
covered by the appended claims. It is also anticipated that
advances in science and technology will make equivalents and
substitutions possible that are not now contemplated by reason of
the imprecision of language and these variations should also be
construed where possible to be covered by the appended claims.
* * * * *