U.S. patent application number 16/691917 was filed with the patent office on 2021-05-27 for metallic coating and method of application.
The applicant listed for this patent is HAMILTON SUNDSTRAND CORPORATION. Invention is credited to Weina Li, Georgios S. Zafiris, Weilong Zhang.
Application Number | 20210156041 16/691917 |
Document ID | / |
Family ID | 1000004522254 |
Filed Date | 2021-05-27 |
United States Patent
Application |
20210156041 |
Kind Code |
A1 |
Zhang; Weilong ; et
al. |
May 27, 2021 |
METALLIC COATING AND METHOD OF APPLICATION
Abstract
A method of depositing a high entropy metal alloy coating onto a
substrate includes mixing metallic salts of one or more elements
with a solvent to form a mixture, heating the mixture to form a
liquid, such that constituents of the liquid are in a mobile ionic
state, and electroplating the metallic salts onto a substrate from
the ionic liquid. A solution for electroplating is also
disclosed.
Inventors: |
Zhang; Weilong;
(Glastonbury, CT) ; Li; Weina; (South Glastonbury,
CT) ; Zafiris; Georgios S.; (Glastonbury,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HAMILTON SUNDSTRAND CORPORATION |
Charlotte |
NC |
US |
|
|
Family ID: |
1000004522254 |
Appl. No.: |
16/691917 |
Filed: |
November 22, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25D 3/665 20130101;
C25D 3/56 20130101 |
International
Class: |
C25D 3/66 20060101
C25D003/66; C25D 3/56 20060101 C25D003/56 |
Claims
1. A method of depositing a metallic coating onto a substrate,
comprising: mixing metallic salts of one or more elements with a
solvent to form a mixture; heating the mixture to form a liquid,
such that constituents of the mixture are in a mobile ionic state;
and electroplating the metallic salts onto a substrate from the
liquid.
2. The method of claim 1, wherein the mixture has a eutectic point
that is lower than about 100.degree. C.
3. The method of claim 2, wherein the heating is to a temperature
at or near the eutectic point.
4. The method of claim 3, wherein the heating is to a temperature
that is between the eutectic point and a temperature 10.degree. C.
above the eutectic point.
5. The method of claim 2, wherein the eutectic point is between
about 10.degree. C. and 100.degree. C.
6. The method of claim 1, wherein the one or more elements includes
one or more refractory metals.
7. The method of claim 6, wherein the one or more elements includes
at least one of zirconium, niobium, titanium, tantalum, molybdenum,
tungsten, rhenium, and hafnium, and combinations thereof.
8. The method of claim 6, wherein the one or more elements includes
at least one metal selected from the group of zirconium, niobium,
titanium, tantalum, molybdenum, tungsten, rhenium, and hafnium.
9. The method of claim 1, wherein the one or more elements includes
at least one of zirconium, niobium, titanium, tantalum, molybdenum,
tungsten, rhenium, and hafnium.
10. The method of claim 1, wherein the substrate is a component of
a gas turbine engine.
11. The method of claim 1, wherein the substrate includes at least
one non-line-of-sight surface, and the electroplating is on the at
least one non-line-of-sight-surfaces.
12. The method of claim 1, wherein the liquid is free from
water.
13. The method of claim 1, wherein the solvent is selected from the
group of an ionic liquid and a deep eutectic solvent.
14. The method of claim 13, wherein the solvent is a deep eutectic
solvent, and includes at least one of choline chloride with urea,
ethylene glycol, glycerol, and malonic acid.
15. A solution for electroplating, comprising: a mixture of
metallic salts of one or more refractory metal elements and a
solvent, wherein the mixture has a eutectic point below about
100.degree. C.
16. The solution of claim 15, wherein the eutectic point is between
about 10.degree. C. and 100.degree. C.
17. The solution of claim 15, wherein the refractory metal elements
include at least one of zirconium, niobium, titanium, tantalum,
molybdenum, tungsten, rhenium, and hafnium, and combinations
thereof.
18. The solution of claim 15, wherein the refractory metal elements
include at least one metal selected from the group of zirconium,
niobium, titanium, tantalum, molybdenum, tungsten, rhenium, and
hafnium.
19. The solution of claim 15, wherein the mixture is free from
water.
20. The solution of claim 15, wherein the solvent is selected from
the group of an ionic liquid and a deep eutectic solvent.
Description
BACKGROUND
[0001] Metallic coatings are applied to substrates to protect the
substrate. For instance, the metallic coatings can provide
corrosion resistance, high temperature oxidation resistance,
protection from mechanical damage (e.g., scratching) or other
protections for the substrate. Metallic coatings, and in particular
refractory metal coatings that comprise high entropy alloys (HEAs)
are typically applied to substrates in a very limited variety of
ways, including ball milling and sintering, arc induction plasma
melting, plasma spray, or laser cladding. However, it is difficult
to apply coatings to non-line-of-sight surfaces, such as internal
cooling passages of a component, with these methods. Some metallic
coatings can be applied to non-line-of-sight surfaces by
electroplating. However, electroplating requires the preparation of
a solution containing metallic cations dissolved in a carrier
liquid. An electrical current is applied to the solution to deposit
the metallic cations into a substrate. Preparing such an aqueous
solution for electrodeposition of HEA is difficult and expensive,
and leads to poor coating structure and low current efficiencies
due to the high rate of hydrogen reduction and evolution at the
substrate cathode, which makes electrodepositon of refractory HEA
from such an aqueous solution difficult and impractical.
SUMMARY
[0002] A method of depositing a metallic coating onto a substrate
according to an example of this disclosure includes mixing metallic
salts of one or more elements with a solvent to form a mixture,
heating the mixture to form a liquid, such that constituents of the
mixture are in a mobile ionic state, and electroplating the
metallic salts onto a substrate from the liquid.
[0003] In a further example of the foregoing, the mixture has a
eutectic point that is lower than about 100.degree. C.
[0004] In a further example of any of the foregoing, the heating is
to a temperature at or near the eutectic point.
[0005] In a further example of any of the foregoing, the heating is
to a temperature that is between the eutectic point and a
temperature 10.degree. C. above the eutectic point.
[0006] In a further example of any of the foregoing, the eutectic
point is between about 10.degree. C. and 100.degree. C.
[0007] In a further example of any of the foregoing, one or more
elements include one or more refractory metals.
[0008] In a further example of any of the foregoing, one or more
elements include at least one of zirconium, niobium, titanium,
tantalum, molybdenum, tungsten, rhenium, and hafnium, and
combinations thereof.
[0009] In a further example of any of the foregoing, one or more
elements include at least one metal selected from the group of
zirconium, niobium, titanium, tantalum, molybdenum, tungsten,
rhenium, and hafnium.
[0010] In a further example of any of the foregoing, one or more
elements include at least one of zirconium, niobium, titanium,
tantalum, molybdenum, tungsten, rhenium, and hafnium.
[0011] In a further example of any of the foregoing, the substrate
is a component of a gas turbine engine.
[0012] In a further example of any of the foregoing, the substrate
includes at least one non-line-of-sight surface. The electroplating
is on the at least one non-line-of-sight-surfaces.
[0013] In a further example of any of the foregoing, the liquid is
free from water.
[0014] In a further example of any of the foregoing, the solvent is
selected from the group of ionic liquids and deep eutectic
solvents.
[0015] In a further example of any of the foregoing, the solvent is
a deep eutectic solvent, and incudes at least one of choline
chloride with urea, ethylene glycol, glycerol, and malonic
acid.
[0016] A solution for electroplating according to an example of
this disclosure includes a mixture of metallic salts of one or more
refractory metal elements and a solvent, wherein the mixture has a
eutectic point below about 100.degree. C.
[0017] In a further example of the foregoing, the eutectic point is
between about 10.degree. C. and 100.degree. C.
[0018] In a further example of any of the foregoing, the refractory
metal elements include at least one of zirconium, niobium,
titanium, tantalum, molybdenum, tungsten, rhenium, and hafnium, and
combinations thereof.
[0019] In a further example of any of the foregoing, the refractory
metal elements include at least one metal selected from the group
of zirconium, niobium, titanium, tantalum, molybdenum, tungsten,
rhenium, and hafnium.
[0020] In a further example of any of the foregoing, the mixture is
free from water.
[0021] In a further example of any of the foregoing, the solvent is
selected from the group of ionic liquids and deep eutectic
solvents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 schematically shows an example component.
[0023] FIG. 2 schematically shown an example method of
electroplating a high entropy refractory alloy onto a
substrate.
[0024] The various features and advantages of the disclosed
examples 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.
DETAILED DESCRIPTION
[0025] Metallic coatings can be applied to substrates in order to
protect the substrates from high temperatures, corrosion,
mechanical damage, or other conditions. In a particular example,
metallic coatings are applied to substrates, such as gas turbine
engine components, to provide high temperature resistance for the
substrates. FIG. 1 shows an example cross section of a substrate 10
having a coating 12. The coating has a thickness t.
[0026] Metallic coatings can be alloys of multiple metals. One
example type of metallic coating is a high entropy alloy (HEA).
HEAs typically include four or more metallic elements in relatively
high proportions, e.g., the four or more metallic elements each
comprise higher than trace amounts of the HEA. In a particular
example, one or more of the elements is a refractory metal. A
refractory metal HEA coating example comprises at least one of
niobium, molybdenum, tantalum, tungsten, rhenium, and combinations
thereof. Another refractory HEA coating example comprises at least
one of zirconium, niobium, titanium, tantalum, hafnium, and
combinations thereof. And yet another example of a refractory
metals HEA coating comprises at least one of niobium, molybdenum,
tantalum, tungsten, rhenium, zirconium, hafnium, titanium, and
combinations thereof.
[0027] Electroplating is generally known in the art. Essentially,
electroplating includes dissolving metallic cations in a carrier
liquid to form a solution. The solution is then applied to the
substrate, and an electrical current is applied to the solution and
substrate. The electrical current causes the metallic cations to
deposit onto the substrate, forming a coating on the substrate.
Electroplating can be used to apply coatings to non-line-of-sight
surfaces, such as internal cooling passages of a component. For
instance, the component can be submerged in the solution, which
infiltrates the component to the non-line-of-sight surfaces. The
metallic cations can then be electroplated onto the component.
[0028] FIG. 2 shows an example method 100 of electroplating a
metallic coating 12, such as an HEA metal coating, onto a substrate
10. A refractory metal HEA coating is an exemplary case of the
above. In step 102, salts of one or more metallic elements (such as
a refractory metals) are mixed with a solvent to form a mixture.
The resulting mixture is a low temperature eutectic mixture (i.e.,
the mixture has a lower melting point than its individual
components). Example solvents are deep eutectic solvents (DESs) or
ionic liquids. Example ionic liquids are imidazolium, pyridinium,
and quaternary ammonium salts. DESs are eutectic mixtures of two or
more components, typically consisting of a hydrogen-bond acceptor
(HBA), for example a quaternary ammonium halide salt, and a
hydrogen-bond donor (HBD). The charge delocalization occurring
through hydrogen bonding between hydrogen-bond acceptor anions and
hydrogen donor molecules results in a decrease in the melting point
of the liquid mixture as compared with the melting points of the
individual component of DESs. Examples of DESs include eutectic
mixtures of choline chloride with urea, ethylene glycol, glycerol,
malonic acid, or other hydrogen bond donor species of amides,
alcohols or carboxylic acids, respectively.
[0029] In step 104, the mixture is heated to a temperature at or
near its eutectic point to melt it (e.g., form a liquid). For
example, the mixture is heated to a temperature between the
eutectic point and about 10.degree. C. above the eutectic point. In
some examples, the eutectic point of the salt mixture is below
100.degree. C. In a more particular example, the eutectic point is
between about 10.degree. C. and 100.degree. C. Because the eutectic
point is on the order of room temperature, the mixture can be
heated easily and inexpensively by any known means. The heating
causes the constituent chemical species exist in the liquid in a
mobile ionic state (e.g., a liquid that includes ionic assemblies
of the metallic salts (cations) and anions).
[0030] In some examples, the liquid mixture is free from water. For
instance, the metal salts and solvents from step 102 are selected
so that the liquid in step 104 is free from water.
[0031] In step 106, the metal salts (such as refractory metal
cations, in one example) in the liquid mixture are electroplated
onto the substrate 10 as generally discussed above and known in the
art to form the coating 12 on the substrate 10. The electroplating
can be any known type of electroplating, including pulsed
electroplating and potentiostatic electroplating. In potentiostatic
electroplating, the electrical current remains constant through the
process. In pulsed electroplating, the electrical current is
periodically raised and lowered between high and low values, and
the polarity can also be momentarily reversed, to control the
composition and thickness t of the resulting coating 12.
[0032] Refractory metals in particular were previously difficult to
electroplate because the refractory metals have very high melting
points. Creating a low eutectic point liquid with constituents
including the desired refractory metals as discussed above greatly
reduces the heating required to melt the mixture and form the
liquid for electroplating the desired metallic composition onto the
substrate 10 of choice, as discussed above. Therefore, the
above-described method allows for the relatively simple and
inexpensive electrodeposition of metallic coatings such as HEAs
containing one or more refractory metals onto substrates, including
on non-line-of-sign surfaces.
[0033] Use of the above described method overcomes the barriers
involved with electroplating of refractory metals via aqueous
electrolyte baths. The reduction half-reaction for refractory metal
cations generally involves very high potential as compared to other
metals like nickel, zinc, etc. This means that if the carrier
liquid includes water, the reaction system will tend towards the
electrolysis of water, which reaction has a much lower potential
than the electroplating reaction for other metals. This in turn
produces hydrogen, which is detrimental to the properties of the
substrate metal (e.g. hydrogen embrittlement). In addition, the
electroplating efficiency (e.g., amount of metallic coating
deposited on the substrate over time) is low. To counteract this,
very high voltages would be required to be applied to create the
electrical current to drive the electroplating. However, in some
examples, the above-described method includes a liquid including
refractory metal that is free from water and can be used for
electrodeposition. Accordingly, by using the above described method
with a water-free liquid, electroplating of refractory metals and
metal alloys becomes possible.
[0034] 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.
[0035] In some examples, plasma deposition of refractory metal
alloys would create different surface morphologies and potentially
compositions compared to electrodeposited coatings via the method
described in the present invention.
[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 the essence of this disclosure. The scope
of legal protection given to this disclosure can be determined by
studying the following claims.
* * * * *