U.S. patent application number 13/216954 was filed with the patent office on 2013-02-28 for substrates coated with wear resistant layers and methods of applying wear resistant layers to same.
This patent application is currently assigned to Pratt & Whitney. The applicant listed for this patent is Robert A. Barth, Wayde R. Schmidt. Invention is credited to Robert A. Barth, Wayde R. Schmidt.
Application Number | 20130052437 13/216954 |
Document ID | / |
Family ID | 46799064 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130052437 |
Kind Code |
A1 |
Barth; Robert A. ; et
al. |
February 28, 2013 |
Substrates Coated with Wear Resistant Layers and Methods of
Applying Wear Resistant Layers to Same
Abstract
Components with improved erosion resistance are disclosed. A
surface of the component or a substrate of the component is
modified by coating the substrate with an elastomer layer. The
elastomer layer is then modified by embedding hard particles onto
an outer side of the elastomer layer. The hard particles exhibit
higher fractured toughness providing enhanced erosion protection.
The elastic properties of the elastomer experience little reduction
because the surface embedded particles are located only at the
outer side or outer surface of the elastomer layer. Therefore, the
bond between the inner side of the elastomer layer and the
substrate or component surface is not interfered with and the
potential for electro-chemical corrosion and poor adhesion are not
increased by the presence of the hard particles as the hard
particles are located away from the inner face between the
elastomer layer and the substrate.
Inventors: |
Barth; Robert A.; (South
Windsor, CT) ; Schmidt; Wayde R.; (Pomfret Center,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Barth; Robert A.
Schmidt; Wayde R. |
South Windsor
Pomfret Center |
CT
CT |
US
US |
|
|
Assignee: |
Pratt & Whitney
|
Family ID: |
46799064 |
Appl. No.: |
13/216954 |
Filed: |
August 24, 2011 |
Current U.S.
Class: |
428/213 ;
416/224; 427/197; 427/202; 428/323; 428/336; 428/411.1; 428/421;
428/423.1; 428/425.5; 428/425.8; 428/425.9; 428/447; 428/474.4;
428/477.7; 428/688; 428/697; 428/698; 428/702; 428/704 |
Current CPC
Class: |
Y10T 428/31504 20150401;
Y10T 428/31598 20150401; Y10T 428/31605 20150401; B05D 7/50
20130101; B05D 7/54 20130101; B05D 2490/50 20130101; B05D 5/00
20130101; Y10T 428/31725 20150401; Y10T 428/31609 20150401; Y10T
428/31765 20150401; B05D 1/12 20130101; B05D 2425/01 20130101; B05D
2425/01 20130101; Y10T 428/31551 20150401; B05D 2601/20 20130101;
B05D 2401/32 20130101; B05D 2425/01 20130101; Y10T 428/2495
20150115; Y10T 428/31663 20150401; B05D 2601/20 20130101; Y10T
428/25 20150115; Y10T 428/265 20150115; Y10T 428/3154 20150401 |
Class at
Publication: |
428/213 ;
416/224; 428/411.1; 428/421; 428/447; 428/423.1; 428/323; 428/336;
427/197; 427/202; 428/474.4; 428/702; 428/698; 428/704; 428/688;
428/697; 428/425.5; 428/425.8; 428/477.7; 428/425.9 |
International
Class: |
F01D 5/14 20060101
F01D005/14; B32B 27/40 20060101 B32B027/40; B32B 5/16 20060101
B32B005/16; B32B 3/00 20060101 B32B003/00; B32B 15/08 20060101
B32B015/08; B05D 1/36 20060101 B05D001/36; B32B 27/34 20060101
B32B027/34; B32B 19/02 20060101 B32B019/02; B32B 7/02 20060101
B32B007/02; B32B 27/06 20060101 B32B027/06; B32B 9/04 20060101
B32B009/04; B05D 5/00 20060101 B05D005/00 |
Claims
1. A component comprising: a substrate comprising an outer surface,
the outer surface being at least partially covered by an elastomer
layer, the elastomer layer having an inner side that is bonded to
the outer surface of the substrate, the elastomer layer further
having an outer side that is at least partially embedded with a
plurality of particles.
2. The component of claim 1 wherein the inner side of the elastomer
layer is free of particles.
3. The component of claim 1 wherein the inner side of the elastomer
layer is chemically bonded to the outer surface of the
substrate.
4. The component of claim 1 wherein the inner side of the elastomer
layer is mechanically bonded to the outer surface of the
substrate.
5. The component of claim 1 wherein the inner side of the elastomer
layer is chemically and mechanically bonded to the outer surface of
the substrate.
6. The component of claim 1 wherein the component is selected from
the group consisting of a propeller, a helicopter rotor blade, a
compressor blade of a gas turbine engine, a fan blade of a gas
turbine engine, a rotor blade of a pump, a rotor blade of a
compressor and a fan blade of a heating-ventilation-air
conditioning system (HVAC).
7. The component of claim 1 wherein the elastomer layer comprises
an elastomer selected from the group consisting of a fluoropolymer,
a polyurea, a polyurethane and a silicone.
8. The component of claim 1 wherein the particles are selected from
the group consisting of alumina, silicon carbide, silicon nitride,
boron carbide, tungsten carbide, steel alloys, nickel alloys,
diamond, chromium carbide, mullite, zirconia, yttria-stabilized
zirconia, magnesium-stabilized zirconia and combinations
thereof.
9. The component of claim 1 wherein the elastomeric layer comprises
two elastomer layers including a first layer having the inner side
that is affixed to the substrate and a second layer having the
outer side that is at least partially embedded with particles.
10. The component of claim 1 wherein the particles have sizes
ranging from about 5 microns to about 3000 microns.
11. The component of claim 1 wherein the elastomer layer has a
thickness equal to or greater than about 25 microns.
12. The component of claim 11 wherein from about 1% to about 99% of
the thickness of the elastomer layer is embedded with
particles.
13. The component of claim 11 wherein from about 1% to about 50% of
the thickness of the elastomer layer is embedded with
particles.
14. The component of claim 11 wherein from about 5% to about 10% of
the thickness of the elastomer layer is embedded with
particles.
15. A component comprising: a substrate having an outer surface; an
elastomer layer affixed to the outer surface of the substrate,
wherein elastomer layer is fabricated from an elastomer selected
from the group consisting of a polyurethane, a polyurea, a silicone
and a fluoropolymer, and wherein the elastomer layer has an outer
side disposed opposite the elastomer layer from the substrate and
an inner side that is affixed to the outer surface of the
substrate, the outer side of the elastomer layer being embedded
with particles, the inner side of the elastomer layer being free of
particles; the particles being fabricated from at least one
material selected from the group consisting of alumina, silicon
carbide, silicon nitride, boron carbide, tungsten carbide, steel
alloys, nickel alloys, diamond, chromium carbide, mullite,
zirconia, yttria-stabilized zirconia, magnesium-stabilized zirconia
and combinations thereof.
16. The component of claim 15 wherein the particles have a size
ranging from about 5 microns to about 3000 microns.
17. The component of claim 15 wherein the elastomer layer comprises
two elastomer layers including a first layer having the inner side
that is affixed to the substrate and a second layer having the
outer side that is at least partially embedded with particles.
18. The component of claim 16 wherein elastomer layer has a
thickness equal to or greater than about 25 microns.
19. A method for improving erosion resistance of a substrate by
coating the substrate with at least one elastomer layer and
controlling the surface energy of an exposed surface of the at
least one elastomer layer, the method comprising: coating the
substrate with at least one elastomer layer, the at least one
elastomer layer including an inner side that engages the substrate
and an outer side disposed opposite the at least one elastomer
layer from the inner side; partially curing the at least one
elastomer layer; applying the particles to the partially-cured at
least one elastomer layer so the particles embed into the outer
side of the elastomer layer but do not pass through the elastomer
layer to an inner side of the elastomer layer.
20. The method of claim 19 wherein the particles are sprayed onto
the partially-cured at least one elastomer layer.
21. The method of claim 19 wherein the particles are applied to the
partially-cured at least one elastomer layer by placing a screen
over the partially-cured at least one elastomer layer and pressing
the particles through the screen to the partially-cured at least
one elastomer layer.
22. The method of claim 19 wherein the partially-cured at least one
elastomer layer includes a first layer that engages the substrate
and a second layer disposed on the first layer and opposite the
first layer from the substrate, and the coating of the substrate
includes coating the first layer on the substrate followed by
coating the second layer on the first layer, and the applying of
the particles includes mixing the particles with elastomer of the
second layer before the second layer is coated onto the first
layer.
23. The method of claim 19 wherein the applying of the particles to
the partially-cured at least one elastomer layer includes pressing
the particles onto the outer side of the partially-cured at least
one elastomer layer.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to erosion resistant
coatings for substrates and methods of applying such erosion
resistant coatings to substrates.
BACKGROUND
[0002] The durability of helicopter rotor blades is dependent to a
large extent on the erosion of the component by friction or by
impact of finely divided solid or liquid particles. There is no way
to avoid this friction or particulate impact during use of these
components and therefore some means is needed to protect the
components against erosion.
[0003] For example, the air through which the helicopter rotor
blade rotates may contain particulate matter, such as sand. The
size of the sand particles typically ranges from about 0.1 to 2000
microns and more typically from about 20 to 30 microns in diameter.
If the air contains sand, the sand impinges upon the rotor blades
as they rotate, thereby causing abrasion to the blades, or at least
to portions thereof. Unless the blades are adequately protected,
such repetitive abrasive contact can eventually cause the blades to
erode.
[0004] The potential for erosion also exists if the rotor blades
circulate through air containing water droplets. The size of water
droplets ranges from about 1000 to 4000 microns and is typically
about 2000 microns in diameter. Although the size of the water
droplets is typically greater than the size of sand, under high
velocity conditions, water droplets may behave similar to sand,
thereby causing erosion to the rotating rotor blades.
[0005] Moreover, the combination of rain and sand can exacerbate
the amount of abrasion and/or erosion. As a result, when
translating a component through air comprising both rain and sand,
the potential for erosion further increases.
[0006] The potential for erosion is also a function of the force at
which the particulate matter impacts the rotor blade. Specifically,
as the impact force increases, so does the potential for erosion.
The force at which the particulate matter impacts the rotor blade
is dependent upon the geometric shapes of both the rotor blade and
the impacting particle and their relative velocities. For example,
the leading edge of a rotor blade is the portion of the blade that
first cleaves through the air. Therefore, the leading edge is the
portion of the blade most susceptible to erosion caused by the
abrasive contact of particulate matter.
[0007] The amount of erosion to the rotor blade is also a function
of the velocity at which the blade impacts the particulate matter
or vice versa. In other words, the potential for erosion increases
as the speed of the blade increases. For example, because a rotor
blade typically rotates around a central axis, the velocity of the
rotor blade, relative to the air, differs along the leading edge of
the blade. More specifically, the velocity at a point on a blade is
equal to the product of the distance from the center rotational
axis and the rotational velocity. As the distance from the
rotational axis along the leading edge increases, so does the
rotational velocity. The outboard tip of the rotor blade is the
furthest from the rotational axis. Therefore, the potential for
erosion is greatest at the outboard tip of the leading edge of the
rotor blade.
[0008] Various techniques have been attempted to minimize the
amount of erosion to the leading edge of rotor blades. One
technique includes adhesively bonding an appropriately shaped piece
of ductile metal onto the leading edge of the blade, such that the
ductile metal is an integral part of the blade. The ductile metal
leading edge is typically constructed of nickel, which provides
increased wear resistance. The extended exposure of the nickel to
the impinging particulate matter, however, causes the ductile metal
leading edge to erode. The eroded nickel must, therefore, be
replaced. Because the ductile metal leading edge is adhesively
bonded to the blade, replacing the ductile metal leading edge
requires a certain amount of time and skill, which is not typically
available in the field.
[0009] Repairs that are performed in the field are referred to as
"field level" repairs because such repairs require an acceptable
amount of time and a minimal amount of skill to complete. Repairs
requiring an extended amount of time and a heightened skill level
occur back at the aircraft depot and are referred to as "depot"
repairs. Depot repairs are undesirable because depot repairs
increase the amount of time that the aircraft is unavailable in
comparison to a field level repair. Because the replacement of the
ductile metal leading edge is considered a depot repair, bonding
ductile metal onto the leading edge of a rotor blade is an
undesirable technique for minimizing erosion.
[0010] One type of "field level" repair technique for improving a
rotor blade's wear resistance includes applying an elastomeric
material to the leading edge of the blade. Typically, the
elastomeric material is applied to the leading edge as a tape. As
the tape becomes worn, it can quickly and easily be removed, and a
new layer of tape can be applied. Unfortunately, the elastomeric
tape must be replaced more frequently than a nickel leading edge
and the ability of the elastomer to resist erosion caused by the
combined rain and sand is less than that of nickel. Specifically,
the elastomeric tape fails to adequately absorb the impact energy
of the particulate matter. Without adequate absorption
capabilities, the elastomer fails to dissipate the impact energy,
thereby allowing the particulate matter to erode the elastomer.
Without frequent replacement of the elastomeric tape, the leading
edge of the rotor blade remains unprotected.
[0011] In an attempt to supplement the deficiencies of elastomeric
tape, current designs include particles disposed in the elastomer
layer. The particles are mixed in with the elastomer material
before it is cured onto the substrate. Unfortunately, the particles
at the interface of the elastomer layer and the substrate can cause
poor bonding to the substrate and/or electrochemical corrosion
problems such as a galvanic coupling. Further, the embedded
particles can adversely affect the elastic properties of the
elastomer coating thereby reducing the ability of the elastomer
coating to absorb energy from particles in the air, such as sand,
water droplets and other debris.
SUMMARY OF THE DISCLOSURE
[0012] To address the above problems, an improved component is
disclosed which comprises a substrate comprising an outer surface.
The outer surface is at least partially covered by an elastomer
layer. The elastomer layer has an inner side that is bonded to the
outer surface of the substrate and an outer side that is at least
partially embedded with a plurality of particles.
[0013] Another improved component is disclosed which comprises a
substrate having an outer surface. An elastomer layer is affixed to
the outer surface of the substrate. The elastomer layer is
fabricated from an elastomer that is selected from the group
consisting of a polyurethane, a polyurea, a silicone and a
fluoropolymer. The elastomer layer has an outer side disposed
opposite the elastomer layer from the substrate and an inner side
that is affixed to the outer surface of the substrate. The outer
side of the elastomer layer is embedded with particles and the
inner side of the elastomer layer is free of particles. The
particles are fabricated from a material selected from the group
consisting of alumina, silicon carbide, silicon nitride, boron
carbide, tungsten carbide, steel alloys, nickel alloys, diamond,
chromium carbide, mullite, zirconia, yttria stabilized zirconia,
magnesium stabilized zirconia and combinations thereof.
[0014] A method for improving the erosion resistance of a substrate
is also disclosed. The method comprises coating the substrate with
at least one elastomer layer. The at least one elastomer layer
includes an inner side that engages the substrate and an outer side
disposed opposite the at least one elastomer layer from the inner
side. The method further includes partially curing the at least one
elastomer layer. The method also further includes applying
particles to the partially-cured at least one elastomer layer so
the particles embed into the outer side of the elastomer layer but
do not pass through the elastomer layer to the inner side of the
elastomer layer. The embedded particles can be used to control the
surface energy of the exposed layer as measured by contact angle
using standard methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a side sectional view of a substrate coated with
an elastomer layer that includes an outer side embedded with
particles (surface embedded particles or SEPs).
[0016] FIG. 2 compares, graphically, the mass of the erodent that
engages the elastomer layer (x-axis) and the mass of the elastomer
layer removed by the erodent (y-axis) for both an untreated
elastomer layer and an elastomer layer treated with particles as
illustrated in FIG. 1.
DETAILED DESCRIPTION
[0017] Referring to FIG. 1, a substrate 10 is illustrated that
includes an outer surface 12 that is at least partially covered by
an elastomer layer 14. The elastomer layer 14 includes an inner
side 16 that covers, is bonded to, affixed to or engaged with the
outer surface 12 of the substrate 10. The elastomer layer 14 also
includes an outer side 18 that is at least partially covered with a
plurality of particles 20. An additional embodiment is also
disclosed in FIG. 1 which includes dual elastomer layers 114, 214.
In this example, the lower elastomer layer 214 can be applied to
the outer surface 12 of the substrate 10 and may be allowed to
cure. Then, the upper layer 114 is prepared and, optionally, the
particles 20 may be mixed with the elastomer of the upper layer 114
and applied to the lower layer 214 thereby providing a dual layer
114, 214 structure wherein the outer layer 114 includes the
plurality of hard particles but which cannot migrate to the inner
layer 214 as the inner layer 214 is cured or at least substantially
cured by the time the outer layer 114 is applied onto the inner
214. The properties of the layers 14, 114 and 214 can be selected
to provide a preferred combination of bonding, erosion protection
and thermal and environmental resistance to the coated substrate
10.
[0018] Other techniques for applying the particles 20 to the
elastomer layer 14 include partially-curing the elastomer layer 14
and spraying or pressing the particles 20 onto the outer side 18 of
the partially-cured elastomer layer. The particles 20 may also be
strategically placed on the outer side 18 of the elastomer layer 14
by using a screen or mesh 22 and pressing or spraying or otherwise
delivering the particles 20 through the screen or mesh 22 onto the
outer side 18 of the partially-cured elastomer layer 14.
[0019] Depending on the type of elastomer and desired properties,
the particles 20 may be fabricated from materials selected from the
group consisting of alumina, silicon carbide, silicon nitride,
boron carbide, tungsten carbide, steel alloys, nickel alloys,
diamond, chromium carbide, mullite, zirconia, yttria stabilized
zirconia, magnesium stabilized zirconia and combinations thereof.
If the particles 20 and the elastomer layer 14 are not inherently
compatible, it may be necessary to add a known coupling agent to
the elastomer in order to combine the elastomer and the particles.
For that matter, the elastomer layer 14 should be selected so that
it is compatible with the substrate 10 and, when cured onto the
substrate 10, the elastomer layer 14 should be mechanically and/or
chemically bonded to the substrate 10.
[0020] It is preferable that the elastomer has a strain to failure
of at least 20% and a tensile strength of at least 1,000 PSI. Even
more preferable, the elastomer may have a strain to failure of at
least 100% and a tensile strength of at least 3,000 PSI. It is
still more preferable that the elastomer has a strain to failure of
at least 1000% and a tensile strength of at least 5,000 PSI.
Elastomers such as polyurethanes, polyureas, silicones or silicone
rubbers and fluoropolymers can satisfy these requirements. Other
suitable elastomers may include, but are not limited to natural
rubber, polyurethanes, chlorosulfonated polyethylene, chlorinated
polyethylene and ethylene-propylene copolymers and terpolymers.
[0021] One example of a possible polyurethane is a product
manufactured by AIR PRODUCTS under the trade name Airthane.RTM..
Examples of potentially suitable fluoropolymers include those
manufactured by Dupont Dow Elastomers under the tradenames
Viton.RTM. and Kalrez.RTM.. E.I. Dupont de Nemours Company also
manufactures Teflon.RTM. fluoropolymer. Another example of a
possible fluoropolymer includes that which is manufactured by the
Minnesota, Mining & Manufacturing Company (3M) under the
tradenames Fluorel.RTM.. Further examples of potential elastomers
include Engage.RTM. polyolefin, Ascium.RTM. and Hypalon.RTM.
chlorinated polyethylenes, and Tyrin.RTM. chlorinated polyethylene,
all manufactured by Dupont Dow Elastomers. Another example of a
possible polymer is a fluorinated polymer, such as
polychlorotrifluoroethylene manufactured by 3M under the tradename
Kel-F.RTM.. Examples of a potential silicone include NuSil R-2180,
fluorosilicone and polydimethylsiloxane.
[0022] It is preferable that the hard particles 20 have a diameter
ranging from about 5 microns to about 3000 microns. It is even more
preferable that the hard particles 20 have a diameter ranging from
about 100 microns to about 1000 microns. It is especially
preferable that the hard particles 20 have a diameter ranging from
about 500 microns to about 800 microns. It is also preferable that
the hard particles 20 have an aspect ratio ranging from about 1 to
about 20. It is even more preferable that the hard particles 20
have an aspect ratio ranging from about 1 to about 10, and it is
especially preferable that the hard particles 20 have an aspect
ratio ranging from about 1 to about 5. It is also preferable that
the hard particles 20 have favorable mechanical and chemical
properties, such as high hardness, abrasion resistance, high
modulus of stiffness, high compressive strength, water resistance,
and thermal stability. It is also preferable that the hard
particles 20 account for from about 1% to about 50% of the volume
of the elastomer/particle layer 14. It is even more preferable that
the hard particles 20 account for from about 1% to about 25% of the
volume of the elastomer/particle layer 14, and it is especially
preferable that the hard particles 20 account for from about 5% to
about 20% of such volume.
[0023] Depending upon the type of elastomer and the desired
properties, the hard particles may comprise a material from the
group consisting of alumina, silicon carbide, silicon nitride,
boron carbide, tungsten carbide, steel alloys, nickel alloys,
diamond, chromium carbide, mullite, zirconia, yttria-stabilized
zirconia, magnesium-stabilized zirconia and combinations thereof.
It is desired to include particles having a hardness generally
higher than that of incoming erodent particles such as sand.
[0024] The elastomer serves as a matrix for the hard particles,
which add the desired physical properties to the elastomer, thereby
increasing the toughness and/or stiffness of the elastomeric
matrix. Incorporating hard particles into the elastomeric matrix
allows an additional pathway for the elastomer to dissipate impact
energy over a larger relative volume because the sizes of the
particulate matter (sand or water) impacting the elastomer are
significantly less than the size of the hard particles within the
elastomeric matrix. It is anticipated that the smaller erodent
particle will impact the reinforcement particle within the
elastomer or with the elastomer itself. If the reinforcement
particle is impacted, the force will be transferred into both the
reinforcement particle and the elastomeric matrix. The elastomer
layer(s) is, thereby, less susceptible to erosion than a pure
elastomer. The particle-embedded elastomer layer 14, therefore,
will typically have a longer useful life compared to a pure
elastomer layer. The elastomer layer 14 will also have a longer
life expectancy than an elastomeric matrix reinforced with
conventional reinforcing particles because the disclosed elastomer
layer 14 with hard particles 20 embedded on its outer side 18 can
absorb a particulate matter's impact energy over a significantly
greater volume. Applying the particle-coated or particle-embedded
elastomer layer 14 onto a substrate such as an airfoil, rotor or
fan, especially a leading edge, reduces the energy density absorbed
by the elastomer layer 14, thereby reducing its potential for
eroding which, in turn, increases the component's erosion
resistance.
[0025] The particles 20 may be partially or totally embedded in the
elastomer layers 14, 114 as illustrated in FIG. 1, but are most
effective when particles are disposed partially on or just below
the outer side 18 of elastomer layers 14, 114. The elastomer layers
14, 114 may have particles deposited to a depth ranging from about
1% to about 99% of the overall thickness of the layer or layers 14,
114. Other suitable particle depth ranges can range from about 1%
to about 50% or from about 5% to about 10%. At least about 1% of
the outer layer 14, 114 thickness would have embedded particles
with an upper limit of about 99% of the outer thickness of the
layers 14, 114 would have embedded particles. One preferred range
is from about 5% to about 10% of the outer layer thickness.
[0026] Turning to FIG. 2, simulated data for an untreated elastomer
layer and a treated elastomer layer 14 is presented graphically.
The line 30 represents an untreated elastomer layer that is being
bombarded with an erodent in the form of sand particles and/or
water particles. The initial dip in the curve is evidence of a
weight gain as the erodent particles are embedded into the
untreated elastomer layer. However, as the untreated elastomer
layer erodes, it loses weight as indicated by the upswing of the
curve 30. The curve 32 represents a treated elastomer layer 14 like
that shown in FIG. 1. The treated elastomer layer 14 also gains
weight as it is initially bombarded with particles, but at an
initially slower rate than the untreated elastomer, and then slowly
begins to lose weight as it erodes. The reader will note the
substantial offset between the curves 30 and 32 thereby
establishing that the treated elastomer layer 14 will take longer
to erode than the untreated elastomer layer represented by the
curve 30.
[0027] Industrial Applicability
[0028] Various components that are susceptible to erosion by sand
or dirt particles and/or water particles may be provided with a
superior erosion-resistant coating in the form of an elastomer
layer 14 with hard particles 20 embedded into or onto the outer
side 18 of the elastomer layer 14. The inner side 16 of the
elastomer layer 14 that engages the substrate 10 is free of
particles and therefore the bond between the inner side 16 and the
outer surface 12 of the substrate 10 will not be interfered with by
the hard particles 20. Further, the risk of causing
electro-chemical corrosion and/or adhesion problems at the
interface between the inner sides 16 of the elastomer layer 14 and
the upper surface 12 of the substrate 10 is avoided by keeping the
hard particles 20 away from this interface.
[0029] The modified elastomer layer 14 as shown in FIG. 1 or the
dual layer 114, 214 with the modified outer layer 114 can be
applied to a variety of components including, but not limited to a
propeller, a helicopter rotor blade, an airfoil, a compressor blade
of a gas turbine, a fan blade of a gas turbine and a rotor blade of
a pump, a rotor blade of a compressor, a fan blade of a
heating-ventilation-air conditioning unit (HVAC) and other
components as will be apparent to those skilled in the art.
* * * * *