CN115873499A

CN115873499A - Protective coating for aircraft engine components

Info

Publication number: CN115873499A
Application number: CN202211201153.3A
Authority: CN
Inventors: 西莫内·尤拉罗; 阿莱西奥·加乔利; 马可·加拉贝洛; 塞尔瓦托·加罗法洛; 恩里卡·吉拉尔迪; 奥塔维亚·皮卡; 朱塞佩·阿根泰利
Original assignee: GE Avio SRL
Current assignee: GE Avio SRL
Priority date: 2021-09-29
Filing date: 2022-09-29
Publication date: 2023-03-31
Also published as: CA3175493C; CA3175493A1

Abstract

An aircraft engine component (100) may include a wall (200) and a protective coating (108) covering the wall (200), the wall (200) comprising an aluminum alloy and/or a magnesium alloy. The protective coating (108) may include a primer layer (206), a silicone elastomer layer (208), and an abrasion resistant layer (210). The base coat (206) may at least partially cover the surface (202) of the wall (200). The primer layer (206) may include a silane coupling agent and an organotitanate. The silicone elastomer layer (208) may at least partially cover the primer layer (206). The silicone elastomer layer (208) may comprise one or more filler materials dispersed in a cross-linked silicone polymer matrix. The abrasion resistant layer (210) may at least partially cover the silicone elastomer layer (208). The wear layer (210) may comprise a fiber reinforced elastomeric material.

Description

Protective coating for aircraft engine components

Cross Reference to Related Applications

The present application claims priority from italian application No. 102021000024893 filed on 9/29, 2021.

Technical Field

The present application relates generally to protective coatings for aircraft engine components, methods of applying protective coatings, and aircraft engine components having protective coatings.

Background

Aircraft engine components, such as gearboxes, fuel tanks, etc., may utilize various forms of protection to mitigate various potential sources of heat, corrosion, fretting, handling, etc. It is desirable to protect these aircraft engine components, for example, to extend operational life. Accordingly, there is a need for improved protective coatings for aircraft engine components, as well as improved methods of applying protective coatings and aircraft engine components having improved protective coatings.

Drawings

A full and enabling disclosure including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures in which:

FIG. 1 schematically depicts a perspective view of an exemplary aircraft engine component;

FIG. 2 schematically depicts a cross-sectional view of a wall of the aircraft engine component of FIG. 1 coated with an exemplary protective coating; and

FIG. 3 shows a flow chart of a method of applying a protective coating to an aircraft engine component.

In the present specification and drawings, repeated reference numerals indicate the same or similar features or elements throughout the application.

Detailed Description

Reference will now be made in detail to exemplary embodiments of the subject matter disclosed herein, one or more examples of which are illustrated in the accompanying drawings. The various examples are provided by way of illustration and should not be construed to limit the present application. Indeed, various modifications and alterations of this application will become apparent to those skilled in the art without departing from the scope of this application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present application cover such modifications and variations as come within the scope of the appended claims and their equivalents.

It should be understood that terms such as "top," "bottom," "outward," "inward," and the like are words of convenience and are not to be construed as limiting terms. As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one element from another and are not intended to indicate the position or importance of the various elements. The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

Approximating language, as used herein and throughout the specification and claims, may be applied to modify any allowable variation 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", "substantially" and "approximately", are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring a value, or of a method or machine for constructing or manufacturing a component and/or system. For example, approximating language may refer to within 10% difference.

Here and throughout the specification and claims, range limitations are combinable and interchangeable, such ranges being identified and including all sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

The present application relates generally to protective coatings for aircraft engine components, as well as methods of applying protective coatings and aircraft engine components having protective coatings. The protective coatings disclosed herein can provide protection against various sources of heat, fire, corrosion, fretting, handling, and the like. Exemplary protective coatings can exhibit good thermal performance in the presence of heat and/or fire while also exhibiting good surface toughness and resistance to corrosive materials. The thermal properties of an exemplary protective coating may include good insulation and/or good ablative properties. Good insulation may include low thermal conductivity. Good ablatability may include high ablation temperatures, high ablation heat, and/or high continuous use temperatures.

The protective coating may provide thermal protection by way of insulation, for example, when the temperature of the protective coating is below the ablation temperature. In addition, or in the alternative, the protective coating may provide thermal protection by way of ablation, for example, when the temperature of the protective coating exceeds the ablation temperature. As used herein, the term "ablation" or "ablative" refers to the thermal protection of solid materials based on physicochemical transformations when exposed to sufficiently high convective or radiant heat. The thermal protection of the protective coating by ablation may be quantified at least in part by a reduction in the heat of phase change and chemical conversion of the protective coating and/or heat flow due to one or more of pyrolysis, charring, melting, sublimation, evaporation, flaking, expansion, and the like. In some embodiments, the protective coating that provides thermal protection by ablation may comprise an intumescent material. As used herein, "intumescent material" refers to a material that expands due to thermal exposure resulting in an increase in volume and a decrease in density. The intumescent material may produce a char, such as a light char or a hard char. Such carbons can exhibit relatively low thermal conductivity. As used herein, "expansion characteristics" refers to expansion and/or char generation due to thermal exposure.

In some embodiments, the protective coating and/or intumescent material that exhibits ablative properties may chemically react upon heating to form an intumescent thermal insulation layer. In addition, or in the alternative, when exposed to heat, one or more components of the protective coating may form a char or melt that may expand to form a porous or sponge-like layer, providing physical protection and thermal insulation to the substrate to prevent further heat exposure.

In addition to good thermal properties, exemplary protective coatings can have a combination of surface toughness and overall softness such that the protective coating can provide good protection against wear and tear. Further, the exemplary protective coating can provide protection against corrosion, for example, in the case of exposure to corrosive materials (e.g., oils, fuels, hydraulic fluids, alkaline liquids, cleaning fluids, solvents, or brines, and other liquids commonly associated with the operation of aircraft, aircraft engines, and related systems).

These and other advantages of the protective coatings disclosed herein may be achieved through a combination of layers that provide a synergistic effect. Exemplary protective coatings may include silane coupling agents and organotitanates, which together provide a stronger bond between the surface of the aircraft component and the silicone polymer that makes up the majority of the thickness of the protective coating. The silane coupling agent and the organotitanate can be dispersed in an organic solvent which leaves little residue. An exemplary protective coating can include a silicone elastomer layer formed from a silicone polymer formulation that includes one or more silicone polymers and one or more filler materials. After curing, the one or more silicone polymers and the one or more filler materials may form a silicone elastomer layer comprising the one or more filler materials dispersed in a cross-linked silicone polymer matrix. In addition, one or more silicone polymers may be combined with the silane coupling agent and/or the organotitanate in the primer layer (prime layer). In some embodiments, the silicone polymer formulation may include a silylating agent that can enhance the bonding of the silicone polymer in the silicone polymer formulation with the silane coupling agent and/or the organotitanate in the primer layer. In addition, or in the alternative, the silylating agent may enhance bonding within the silicone polymer formulation, including bonding between the filler material and the silicone polymer. The inward portion of the protective coating may have a low to medium density, and a soft to medium soft shore a hardness, while the outward portion of the protective coating may have a medium to high density, and a slightly higher shore a hardness, providing a combination of good resistance to wear and impact, and the like.

These and other properties are achieved, at least in part, by the composition of the various portions of the protective coating disclosed herein. For example, by formulating the protective coatings of the present application, much thicker protective coatings can be applied to aircraft components while maintaining good bonding to the aircraft component surface and within the protective coating itself. The combination of good bonding of the surface and interior of the protective coating provides good elasticity while reducing the likelihood of cracks, chips, or delamination, etc., affecting the life of the protective coating. For example, the protective coatings disclosed herein can be several millimeters thick, for example up to 10 millimeters or more. Such enhanced thickness may provide improved protection against heat sources, including improved insulation and/or ablation, as well as improved protection against wear and tear, corrosive materials, and the like. Advantageously, the protective coatings disclosed herein preferably comprise a silicone polymer and a filler material that, upon curing, provide a protective coating that substantially retains its size and shape when exposed to heat and/or flame, e.g., exhibits substantially no thermal expansion below a threshold temperature for continued use. For example, in some embodiments, the protective coatings disclosed herein can withstand continuous operating temperatures up to 315 ℃ or higher. In some embodiments, the protective coating can be formulated to exhibit swelling characteristics, if desired.

In general, the protective coatings disclosed herein are intended to be applied to surfaces of aircraft engine components. However, it should be understood that aircraft engine components are merely one example application of the protective coatings disclosed herein, and that the protective coatings may additionally or alternatively be applied to any component that may benefit from protection from exposure to heat sources, wear and tear, and/or corrosive liquids or other materials. For example, the protective coatings disclosed herein may be applied to any kind of engine, any kind of aircraft component, any kind of industrial equipment, and the like.

Referring now to FIG. 1, an exemplary component 100 may include a gearbox 102 and/or a sump 104. The gearbox 102 may be a power gearbox configured to transfer power from the turbine to a fan or propeller assembly (not shown). For example, the gearbox 102 may include a planetary gear assembly 106 configured to couple a fan or propeller assembly to a turbine. Alternatively, the gearbox 102 may be an accessory gearbox configured to transfer power from the turbine to one or more accessory systems of the aircraft engine or other aircraft system.

As shown in FIG. 1, the protective coating 108 may cover all or a portion of a wall 200 of the component 100 (e.g., the gearbox 102 and/or the tank 104). It will be appreciated that the gearbox 102 and the sump 104 shown in FIG. 1 are provided by way of example and not limitation. Other examples of aircraft engine components that may receive the protective coating 108 include turbine casings, combustors, exhaust ducts, bypass ducts, heat exchangers, fuel systems, oil systems, firewalls, and the like. Indeed, the protective coating 108 disclosed herein may be applied to any aircraft engine component that may be exposed to sources of heat, fire, corrosion, fretting, handling, and the like.

Referring to fig. 2, the protective coating 108 may be applied to the wall 200 of the component 100. The protective coating 108 may be applied to all or a portion of the surface 202 of the wall 200, such as the surface 202 that may be exposed to a heat source 204. Surface 202 may be an outer surface or an inner surface. The heat source 204 may include an existing heat source, such as a flame from a burner or smoke from an exhaust duct. In addition, or in the alternative, the heat source 204 may include a potential heat source, such as an area that may be exposed to flames, sparks, slag, embers, smoke, hot gases, combustion residues, and the like in the event of an emergency or malfunction.

The protective coating 108 disclosed herein is suitable for use with aircraft engine components 100 formed from metal alloys, such as aluminum alloys, magnesium alloys, and alloys comprising a combination of aluminum and magnesium. For example, the protective coating 108 may be suitable for use with the component 100 formed by any manufacturing process, including casting, forging, machining, additive manufacturing, subtractive manufacturing, and the like. For example, the protective layer 108 may be applied to an aluminum alloy containing chromium, copper, iron, magnesium, manganese, titanium, scandium, silicon, or zinc, and combinations of these. Exemplary aluminum alloys may have a composition comprising aluminum, silicon, copper, and magnesium. For example, an aluminum alloy may be formed according to ASM 4215. As other examples, the protective coating 108 may be applied to magnesium alloys that include aluminum, copper, manganese, one or more rare earth elements, silicon, zinc, or zirconium, and combinations of these. An exemplary magnesium alloy may have a composition including magnesium, zinc, rare earth, and zirconium. For example, a magnesium alloy may be formed according to ASM 4439. The protective coating 108 disclosed herein may also be applied to a variety of other materials, including steel alloys, nickel-chromium alloys, carbon fibers, ceramics, plastics, and the like.

As shown in fig. 2 and discussed in more detail herein, the protective coating 108 may generally include a primer layer 206, a silicone elastomer layer 208, and an abrasion resistant layer 210, the primer layer 206 at least partially covering the surface 202 of the wall 200 of the component 100, the silicone elastomer layer 208 at least partially covering the primer layer 206, and the abrasion resistant layer 210 at least partially covering the silicone elastomer layer 208. The primer layer 206 may include a silane coupling agent and an organotitanate. The silicone elastomer layer 208 may include one or more filler materials dispersed in a cross-linked silicone polymer matrix. The abrasion-resistant layer 210 may comprise one or more fiber-reinforced materials dispersed in a cross-linked silicone polymer matrix. In some embodiments, the surface 202 of the wall 200 of the component 100 may receive a surface treatment 212 to prepare the protective coating 108. The surface treatment 212 may be included as a base layer for the protective coating 108, and/or the surface treatment 212 may be defined as a property of the surface 202 of the wall 200 of the component 100 to which the protective coating 108 may be applied.

In some embodiments, the surface treatment 212 may include a chemical conversion coating, such as a chromate conversion coating. In addition, or in the alternative, the surface treatment 212 may include an anodized coating. The surface treatment 212 may provide improved adhesion between the surface 202 of the wall 200 and the primer layer 206. The chemical conversion coating may be applied by immersing the component 100 in a chemical bath containing suitable metal ions, such as chromium ions. The anodized coating can be applied by immersing the component 100 in an electrolytic bath containing a suitable acid (e.g., chromic acid, sulfuric acid, phosphoric acid, etc.) while passing an electric current through the bath. Chromate conversion coatings and/or anodized coatings may be particularly suitable for use with components 100 formed from aluminum alloys and/or magnesium alloys.

The primer layer 206 may be coated on all or a portion of the surface 202 of the wall 200 of the component 100. In some embodiments, the primer layer 206 may be coated on the surface 202 that has received the surface treatment 212. The primer layer 206 may include a silane coupling agent and/or an organotitanate. The silane coupling agent may be selected to provide a durable bond between the surface 202 or surface treatment 212 of the component 100 and the silicone elastomer layer 208 coated on the primer layer 206. The silane coupling agent may have hydrolyzable functional groups such as acyloxy, alkoxy, amine, butyl, ethoxy, ethyl, halogen, or phenyl groups, and combinations thereof. The hydrolysable functional groups can form stable condensation products with aluminium oxides and/or magnesium oxides and other metal oxides. After hydrolysis, the silane coupling agent may have silanol groups that may react with the silicone polymer to form siloxane bonds during curing of the formulation used to form the silicone elastomer layer 208. These siloxane bonds may be particularly stable, thereby promoting good adhesion between the primer layer 206 and the silicone elastomer layer 208. Exemplary silane coupling agents may include trialkoxysilanes, monoalkoxysilanes, or bipedal silanes. Other exemplary silane coupling agents may include silicates, such as tetramethoxysilane, methyl silicate, tetraethoxysilane, polyethyl silicate, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, or tetra (butoxyethoxy) silane, and combinations thereof.

Similarly, the organic titanate may be selected to provide a durable bond between the surface 202 or surface treatment 212 of the component 100 and the silicone elastomer layer 208 to be coated on the primer layer 206. The organotitanate may have hydrolyzable functionality that can react with aluminum oxide and/or magnesium oxide and other metal oxides. In some embodiments, hydrolysis of the organotitanate may form a monolayer on the surface 202 or surface treatment 212 of the component 100, e.g., no condensation products are produced. In addition, or in the alternative, the organotitanate may have thermosetting functional groups that may form bonds with the hydrocarbon chain of the silicone polymer, and/or the organotitanate may have a hydrocarbon chain that may be bonded to the silicone polymer by van der waals forces. Exemplary thermosetting functional groups of the organotitanate can include acrylate, alkyl, amine, carboxylic acid, epoxy, hydroxyl, thiol, or vinyl groups, and combinations thereof. In addition, or in the alternative, in some embodiments, the organic titanate may be hydrolyzed to produce titanium oxide (e.g., titanium dioxide), which may catalyze or react with the silicone polymer in the formulation used to form the silicone elastomer layer 208. For example, the organotitanate can comprise from about 15mol% to about 30mol% titania, such as from about 20mol% to about 25mol%. Exemplary organotitanates can include ethyl acetoacetate titanate, di-isobutoxy titanium, di-n-butoxy titanium, diisopropoxy titanium, n-butyl polytitanate, tetra-n-butyl titanate, tetrabutyl titanate, titanium butoxide, ethyl acetoacetate titanium or tetraisopropoxide titanium, and combinations thereof.

The primer layer 206 may be provided in a solution comprising a silane coupling agent, an organotitanate, and an organic solvent (e.g., an aliphatic solvent). In an exemplary embodiment, the organic solvent may include naphtha. The organic solvent (e.g., naphtha) may be selected to leave little or no residue. The substantial absence of residue from the primer promotes good functionality of the silane coupling agent and the organotitanate, for example in cross-linking reactions with the silicone polymer in the silicone elastomer layer 208. The solution may contain an organic solvent in an amount of about 75wt% to about 95wt%, such as from about 77wt% to about 94wt%, or such as from about 80wt% to about 85wt%. The amount of silane coupling agent in the solution can be from about 2wt% to about 10wt%, for example from about 4wt% to about 6wt%. The organic titanate may be present in the solution in an amount of about 2wt% to about 10wt%, for example about 4wt% to about 6wt%. For example, an exemplary solution that may be used to apply the undercoat 206 may comprise about 75wt% to about 95wt% (e.g., about 82wt% to about 88 wt%) light aliphatic naphtha, about 4wt% to about 6wt% tetra (2-butoxyethyl) n-silicate, and about 4wt% to about 6wt% tetra-n-butyl titanate. Such solutions are commercially available, for example DOWSIL from Dow chemical company (Midland, mich.) ^TM PR-1200。

After at least partial evaporation, preferably complete evaporation, of the organic solvent, the primer layer 206 may comprise the following silane coupling agent: about 15wt% to about 85wt%, such as about 15wt% to about 40wt%, such as about 40wt% to about 60wt%, or such as about 60wt% to about 85wt%. In addition, or in the alternative, after at least partial evaporation, preferably complete evaporation, of the organic solvent, the primer layer 206 may comprise an organic titanate in an amount such that: about 15wt% to about 85wt%, such as about 15wt% to about 40wt%, such as about 40wt% to about 60wt%, or such as about 60wt% to about 85wt%.

A silicone elastomer layer 208 may be coated on at least a portion of the primer layer 206. The silicone elastomer layer 208 may be provided by way of one or more silicone polymer formulations that may be applied to the primer layer 206 using standard spray equipment and/or using standard doctor blade/molding equipment. After curing, the one or more silicone polymer formulations may comprise one or more filler materials dispersed in a cross-linked silicone polymer matrix. The silicone polymer formulations disclosed herein may be used to form a silicone elastomer layer 208, the silicone elastomer layer 208 having good insulation and/or good ablative properties in the presence of a heat source 204. The silicone elastomer layer 208 may also exhibit good elasticity, for example, may provide protection against wear and tear caused by impacts, scratches, kinks, etc. that may occur during installation, maintenance, handling and operation. An exemplary silicone polymer formulation may include more than one silicone polymer and more than one filler material. More than one silicone polymer may be crosslinked or cured, for example by any suitable crosslinking agent. In addition, or in the alternative, more than one silicone polymer may be self-curing at atmospheric humidity.

Exemplary silicone polymers may comprise Room Temperature Vulcanizing (RTV) silicone or liquid silicone rubber, and combinations thereof. Suitable RTV silicones can be cured in the presence of atmospheric moisture, for example in the case of one-component silicone formulations, which may sometimes be referred to as "RTV 1 silicones". In addition, or in the alternative, suitable RTV silicones may be cured in the presence of a catalyst, for example in the case of a two-component silicone formulation, which may sometimes be referred to as "RTV 2 silicone". The curing process of such RTV silicones can be facilitated by heat or pressure. The silicone polymer may be derived from one or more polyorganosiloxanes, such as polydimethylsiloxane, polymethylhydrosiloxane, dimethyldiphenylpolysiloxane, dimethyl/methylphenylpolysiloxane, polymethylphenylsiloxane, methylphenyl/dimethylsiloxane, vinyldimethyl-terminated polydimethylsiloxane, vinylmethyl/dimethylpolysiloxane, vinyldimethyl-terminated vinylmethyl/dimethylpolysiloxane, divinylmethyl-terminated polydimethylsiloxane, vinylphenylmethyl-terminated polydimethylsiloxane, dimethylhydrogen-terminated polydimethylsiloxane, methylhydro/dimethylpolysiloxane, methylhydro-terminated methyloctylpolysiloxane, methylhydro/phenylmethylpolysiloxane, oligosiloxanes or fluorine-modified polysiloxanes, and combinations thereof. To form the silicone elastomer, the one or more polyorganosiloxanes can be crosslinked using any suitable technique, such as catalyst curing, thermal curing, and the like. Any suitable crosslinking agent may be used, such as alkoxysilanes having more than one crosslinking functional group (e.g., alkyl, alkenyl, carboxyl, and combinations thereof). Any suitable catalyst may also be used, such as a platinum catalyst, a peroxide catalyst, or a tin catalyst. It is to be understood that the above-described silicone polymer components are provided by way of example and not limitation, that the silicone elastomer layer 208 may comprise other types of silicone polymers, and/or that the silicone elastomer layer 208 may comprise other components, without departing from the scope of the present application.

The silicone elastomer layer 208 may include one or more filler materials dispersed in a cross-linked silicone polymer matrix. Exemplary filler materials that may be included in the silicone polymer formulation that may be used to form the silicone elastomer layer 208 include: glass microspheres (hollow or solid), glass fibers, cenospheres (cenospheres), fumed silica, precipitated silica, silica fibers, silica, silicon carbide, titanium dioxide, zinc oxide, rare earth minerals, silicate minerals, inosilicates, aluminum silicate, alumina trihydrate, polyepoxide microparticles, phenolic resin microspheres (hollow or solid), ceramics, carbon fibers, carbon black, graphene, cellulose fibers, or cork, and combinations thereof. Exemplary filler materials may have an average cross-sectional width of about 10 nanometers (nm) to about 1,000 micrometers (μm), such as about 10nm to about 1,000nm, such as about 100nm to about 500nm, such as about 1 μm to about 1,000 μm, such as about 10 μm to about 500 μm, or such as about 100 μm to about 1,000 μm. It should be understood that the above-described filler materials are provided by way of example and not limitation, and that the silicone elastomer layer 208 may comprise other types of filler materials without departing from the scope of the present application.

The particular filler material and amount thereof in the silicone polymer formulation may be selected to achieve the desired material properties of the resulting silicone elastomer layer 208. The exemplary silicone elastomer layer 208 may include one or more fillers in the following amounts (alone or in combination): from about 0.1% to about 90% by volume, for example from about 1% to about 80% by volume, for example from about 5% to about 60% by volume, for example from about 10% to about 60% by volume, for example from about 20% to about 50% by volume, for example from about 30% to about 40% by volume, or for example from about 60% to about 90% by volume. The total filler content of the silicone elastomer layer 208 may be at least about 1 vol%, such as at least about 5 vol%, such as at least about 10 vol%, such as at least about 20 vol%, such as at least about 30 vol%, such as at least about 40 vol%, such as at least about 50 vol%, such as at least about 60 vol%, such as at least about 70 vol%, such as at least about 80 vol%.

In some embodiments, the silicone elastomer layer 208 may include a silylating agent, such as an aminosilane, a glycidoxysilane, or a mercaptosilane, and combinations thereof. The silylating agent can form siloxane bonds between one or more materials in the silicone polymer formulation used to form the silicone elastomer layer 208 and one or more components of the primer layer 206. For example, the silylating agent may form siloxane bonds between the organic titanate of the primer layer 206 and the silicone polymer in the formulation used to form the silicone elastomer layer 208. In addition, or in the alternative, the silylating agent may form siloxane bonds between the organic titanate of the primer layer 206 and one or more filler materials in the formulation used to form the silicone elastomer layer 208, and/or between the silicone polymer and one or more filler materials in the formulation used to form the silicone elastomer layer 208. Suitable aminosilanes may include (3-aminopropyl) triethoxysilane, (3-aminopropyl) -diethoxy-methylsilane, (3-aminopropyl) -dimethyl-ethoxysilane, (3-aminopropyl) -trimethoxysilane. Exemplary glycidoxysilanes can include (3-glycidoxypropyl) -dimethyl-ethoxysilane. Exemplary mercaptosilanes include (3-mercaptopropyl) -trimethoxysilane and (3-mercaptopropyl) -methyl-dimethoxysilane.

In some embodiments, the silicone elastomer layer 208 may comprise an intumescent material. The intumescent material may include a material that generates char when exposed to heat. For example, the silicone polymer formulation may include an intumescent material. In some embodiments, the silicone polymer may exhibit swelling characteristics. In addition, or in the alternative, the silicone elastomer layer 208 may include more than one intumescent material that acts as a filler material. For example, more than one intumescent material may be dispersed in a cross-linked silicone polymer matrix. Other exemplary intumescent materials that may be included in the silicone elastomer layer 208 include vinyl acetate, styrene acrylate, and combinations thereof. Exemplary intumescent materials may include soft carbon formulations. The soft carbon formulation may comprise ammonium polyphosphate, pentaerythritol, or melamine, and combinations thereof. Soft carbon formulations can produce light char when exposed to heat. In addition, or in the alternative, an exemplary intumescent material may comprise a hard char preparation. The hard carbon formulation may comprise more than one sodium silicate, more than one ammonium phosphate or graphite, and combinations thereof. Hard char preparations may produce hard char upon exposure to heat. One or more intumescent materials (e.g., one or more components of a soft char formulation and/or one or more components of a hard char formulation) may be dispersed in a matrix (e.g., a cross-linked silicone polymer, acetate copolymer, or styrene acrylate polymer matrix, and combinations thereof). The expanded material may form a microporous carbonaceous foam, for example, as a result of a chemical reaction of more than one component in the expanded material.

After curing, the silicone elastomer layer 208 may have good thermal properties to withstand exposure to the heat source 204, including good insulation and/or good ablative properties. For example, after curing, the silicone elastomer layer 208 can have a thermal conductivity of about 0.05W/mK to about 0.15W/mK, such as about 0.07W/mK to about 0.12W/mK, or such as about 0.08W/mK to about 0.11W/mK, measured at 38 ℃ according to ASTM C177. In addition, or in the alternative, for example, the silicone elastomer layer 208 can have a specific heat of about 1.0kJ/kg-K to about 1.6kJ/kg-K, such as about 1.2kJ/kg-K to about 1.6kJ/kg-K, or such as about 1.2kJ/kg-K to about 1.4kJ/kg-K, measured at 24 ℃ according to ASTM E1269-11 (2018). In addition, or in the alternative, for example, the silicone elastomer layer 208 may have an ablation temperature of from about 450 ℃ to about 600 ℃, such as from about 475 ℃ to about 550 ℃, or such as from about 500 ℃ to about 525 ℃, as measured according to ASTM E285-80 (2002). In addition, or in the alternative, for example, the silicone elastomer layer 208 is 330 kilojoules per square meter (kJ/m) per second at heat exposure according to ASTM E458-08 (2020) ² Sec) may be about 40 megajoules/kilogram (MJ/kg) to about 70MJ/kg, or, for example, about 50MJ/kg to about 60MJ/kg. In addition, or in the alternative, the continuous use temperature of the exemplary silicone elastomer layer 208 may be up to at least about 300 ℃, such as up to at least about 315 ℃, or such as up to at least about 325 ℃. In addition, or in the alternative, the example silicone elastomer layer 208 measures heat as the temperature increases from 3 ℃ to 34 ℃The expansion may be from about 0.2% to about 0.01%, such as from about 0.1% to about 0.05%, or such as from about 0.09% to about 0.07%.

In addition to good thermal performance, the exemplary silicone elastomer layer 208 may have a low to medium density, and a soft to medium soft shore a hardness. For example, an exemplary silicone elastomer layer 208 may have a density of about 0.2g/cm ³ To about 0.6g/cm ³ E.g. about 0.2g/cm ³ To about 0.3g/cm ³ For example, about 0.35g/cm ³ To about 0.45g/cm ³ Or, for example, about 0.45g/cm ³ To about 0.55g/cm ³ . For example, the exemplary silicone elastomer layer 208 may have a shore a durometer of about 30 to about 80, such as about 35 to about 45, such as about 40 to about 60, or such as about 60 to about 80, measured according to ASTM D2240-15e 1.

In some embodiments, the exemplary silicone elastomer layer 208 may comprise RTV silicone, glass microspheres, silicone oil, fumed silica, and (3-aminopropyl) triethoxysilane. In addition, or in the alternative, in some embodiments, exemplary silicone elastomer layer 208 may comprise one or more silicone polymers in an amount of about 22wt% to about 26wt%, silica fibers in an amount of about 1wt% to about 5wt%, carbon fibers in an amount of about 1wt% to about 5wt%, silica microspheres in an amount of about 30wt% to about 40wt%, phenolic resin microspheres in an amount of about 4wt% to about 8wt%, and cork in an amount of about 20wt% to about 40 wt%. Exemplary silicone polymer formulations that may be included in the formulation used to form the silicone elastomer layer 208 are commercially available, for example, from Thermal Protection Products (new orleans, louisiana)

Ablating material and/or->

The material is ablated.

After the silicone elastomer layer 208 is at least partially cured, preferably fully cured, a wear layer 210 may be coated on at least a portion of the silicone elastomer layer 208. The abrasion resistant layer 210 may be formed using a formulation that can be applied to the silicone elastomer layer 208 using standard spray, brush or roller equipment. The wear layer 210 may exhibit good toughness. For example, the wear layer 210 may have a medium to high density while still having a soft to medium soft shore a hardness. This combination of medium to high density and soft to medium soft shore a hardness may provide good resistance to fretting and other sources of wear.

The wear layer 210 may comprise a fiber reinforced elastomeric material. The fiber reinforced elastomeric material of the wear layer 210 may comprise more than one polymeric material and more than one fiber reinforced material. More than one fibrous reinforcing material may be dispersed in the matrix of cross-linked polymer material. For example, the polymeric material may be crosslinked or cured by any suitable crosslinking agent. Exemplary polymeric materials that may be included in the formulation used to form the abrasion-resistant layer 210 may include one or more silicone polymers, such as those described above with reference to the silicone elastomer layer 208. In addition, or as an alternative to silicone polymers, other exemplary polymeric materials that may be included in the formulation used to form the abrasion-resistant layer 210 include thermoplastic materials and/or thermoset materials. Exemplary thermoplastic materials include: acrylics, such as polyacrylic acid and polymethyl methacrylate; polyamides, polylactic acids; a polybenzimidazole; a polycarbonate; polyether sulfone; a polyoxymethylene; polyether ether ketone; a polyetherimide; a polyphenylene oxide; polyphenylene sulfide; or polytetrafluoroethylene, and combinations thereof. Exemplary thermosets include epoxy, polyester, polyurethane or vinyl ester resins, and combinations thereof, in addition to silicone polymers. Any one or more of these thermoplastic materials and/or thermoset materials may be included in the formulation used to form the wear layer 210. In addition, or in the alternative, any one or more of these thermoplastic materials and/or thermoset materials may be included in the formulation used to form the silicone elastomer layer 208.

Exemplary fiber reinforcement materials that may be included in the formulation used to form wear layer 210 may include glass fibers, basalt fibers, carbon fibers, ceramic fibers, aramid fibers, polycrystalline fibers, or polysiloxane fibers, and combinations thereof. For example, suitable glass fibers may be made from silica sand, limestone, kaolin, fluorite, colemanite, dolomite or aluminoborosilicate, and combinations thereof. Suitable carbon fibers may be made from polyacrylonitrile, rayon, or pitch precursors, as well as combinations thereof. Suitable ceramic fibers may be made from zirconia, aluminosilicate, polycrystalline alumina, polycrystalline mullite fibers. The ceramic fibers may additionally or alternatively comprise a ceramic matrix composite material, such as silicon carbide polycrystalline fibers. Suitable aramid fibers may include para-aramid fibers, meta-aramid fibers, and/or poly-aramid fibers. Aramid fibers can be made from more than one aromatic polyamide (e.g., para-aramid, para-phenylenediamine, or terephthaloyl chloride). It is understood that the wear layer 210 may contain other types of reinforcing fibers without departing from the scope of this application.

Exemplary fibrous reinforcement materials that may be included in the wear layer 210 may have an average length (e.g., as-spun length or as-cut length) of about 1 micrometer (μm) to about 10,000 μm, such as about 100 μm to about 500 μm, such as about 500 μm to about 1,000 μm, such as about 1,000 μm to about 5,000 μm, or such as about 1,000 μm to about 10,000 μm. In addition, or in the alternative, the average cross-sectional width of the exemplary fibrous reinforcement material may be from about 1 μm to about 50 μm, such as from about 1 μm to about 5 μm, such as from about 5 μm to about 10 μm, such as from about 10 μm to about 25 μm, or such as from about 25 μm to about 50 μm.

The particular fibrous reinforcing material and the amount thereof in the wear layer 210 may be selected to achieve desired material properties. The exemplary wear layer 210 may include one or more fiber reinforcement materials in the following amounts (alone or in combination): from about 0.1% to about 60% by volume, for example from about 1% to about 60% by volume, for example from about 5% to about 60% by volume, for example from about 10% to about 60% by volume, for example from about 20% to about 50% by volume, or for example from about 30% to about 40% by volume. The total content of fibrous reinforcement material of the wear layer 210 may be at least about 1 vol%, such as at least about 5 vol%, such as at least about 10 vol%, such as at least about 20 vol%, such as at least about 30 vol%, such as at least about 40 vol%, such as at least about 50 vol%, or such as at least about 60 vol%.

In addition to the fiber-reinforced material, the wear layer 210 may include one or more filler materials, such as the one or more filler materials described with reference to the silicone elastomer layer 208. In addition, or in the alternative, the silicone elastomer layer 208 may include one or more fiber-reinforced materials in addition to the filler material, such as the one or more fiber-reinforced materials described with reference to the wear layer 210. In addition, or in the alternative, in some embodiments, the abrasion-resistant layer 210 may include an intumescent material, such as one or more of the intumescent materials described with reference to the silicone elastomer layer 208.

After curing, the exemplary wear layer 210 may have a density of about 0.9g/cm ³ To about 1.4g/cm ³ For example, about 1.0g/cm ³ To about 1.3g/cm ³ Or, for example, about 1.1g/cm ³ To about 1.2g/cm ³ . For example, exemplary fiber reinforced elastomer formulations can have a shore a hardness after cure of from about 40 to about 90, such as from about 50 to about 60, such as from about 60 to about 80, or such as from about 80 to about 90, as measured according to ASTM D2240-15e 1.

In addition to the combination of medium to high density and soft to medium soft shore a hardness, exemplary fiber reinforced elastomer formulations may have good thermal properties to withstand exposure to the heat source 204, including good insulation and/or good ablatability. For example, after curing, exemplary fiber reinforced elastomer formulations have a thermal conductivity of from about 0.10W/mK to about 0.25W/mK, such as from about 0.15W/mK to about 0.25W/mK, or such as from about 0.20W/mK to about 0.25W/mK, as measured at 38 ℃ according to ASTM C177. In addition, or in the alternative, for example, exemplary fiber reinforced elastomer formulations can have a specific heat of from about 0.9kJ/kg-K to about 1.5kJ/kg-K, such as from 1.0kJ/kg-K to about 1.1kJ/kg-K, or such as from 1.2kJ/kg-K to about 1.5kJ/kg-K, measured at 38 ℃ according to ASTM E1269-11 (2018). In addition, or in the alternative, for example, the exemplary fiber reinforced elastomer formulation may have an ablation temperature of from about 450 ℃ to about 600 ℃, such as from about 475 ℃ to about 550 ℃, or such as from about 500 ℃ to about 525 ℃, as measured according to ASTM E285-80 (2002). May be included for formingExemplary fiber-reinforced elastomer formulations of the formulation of the fiber-reinforced elastomer layer are commercially available, for example, from Thermal Protection Products (New Orleans, louisiana)

Topcoat。

The thickness of the exemplary protective coating 108 can be 1.2 millimeters (mm) to about 10mm, such as 2mm to about 4mm, such as 4mm to about 6mm, such as 6mm to about 8mm, or such as 8mm to about 10mm. The primer layer 206 can have a thickness of 25 micrometers (μm) to about 50 μm, such as 25 μm to about 40 μm, or such as 35 μm to about 50 μm. The thickness of the silicone elastomer layer 208 may be 1,000 μm to about 10,000 μm, such as 1,000 μm to about 4,000 μm, such as 4,000 μm to about 8,000 μm, or such as 6,000 μm to about 10,000 μm. The wear layer 210 may have a thickness of about 150 μm to about 500 μm, such as about 150 μm to about 300 μm, or such as about 250 μm to about 500 μm.

Referring now to fig. 3, an exemplary method of applying the protective coating 108 (fig. 1 and 2) will be described. As shown, exemplary method 300 may include, at block 302, forming a base coat 206 (FIG. 2) at least partially covering surface 202 (FIG. 2) of wall 200 (FIGS. 1 and 2) of aircraft engine component 100 (FIG. 1). As described herein, the primer layer 206 may include a silane coupling agent and an organotitanate. The primer layer 206 may be applied by wiping, dipping or spraying to form a thin, uniform coating. Excess material for the primer layer 206 may be wiped off to avoid over-coating. Other materials for the primer layer 206 may be applied every 3 to 5 minutes to ensure that fresh material can react with previously applied material. In some embodiments, forming the primer layer 206 may include at least partially curing the primer layer 206, preferably fully curing the primer layer 206. The primer layer 206 may be cured at room temperature (e.g., about 18 ℃ to about 23 ℃) and a relative humidity of about 30% to about 90% (e.g., about 40% to about 70%). The curing time of the primer layer 206 may be about 1 to 2 hours, and may vary depending on temperature and humidity. Moderate heating, such as at a temperature of about 40 ℃ to about 60 ℃, or such as about 50 ℃ to about 60 ℃, can accelerate the cure rate of the primer layer 206.

At block 304, the example method 300 may include forming the silicone elastomer layer 208 (fig. 2) at least partially covering the surface of the primer layer 206. The silicone elastomer layer 208 may be formed using the formulations described herein, which may be applied by conventional spray or roll coating techniques and the like. As described herein, the silicone elastomer layer 208 may include one or more filler materials dispersed in a cross-linked silicone polymer matrix. The silicone elastomer layer 208 may be applied in a series of sub-layers. The thickness of the various sub-layers of the silicone elastomer layer 208 may be about 100 micrometers (μm) to about 500 μm, for example about 200 μm to about 400 μm. The number of sub-layers may be determined based on the desired thickness of the silicone elastomer layer 208 and the thickness of each sub-layer. For example, the exemplary silicone elastomer layer 208 may include about 2 to about 40 sub-layers, such as about 5 to about 10 sub-layers, such as about 10 to about 20 sub-layers, or about 20 to about 40 sub-layers. Sequential sub-layers may be applied after the solvent of a previous sub-layer has flashed off but before full curing. In some embodiments, the application of the silicone elastomer layer 208 to the primer layer 206 may begin after the primer layer 206 is fully cured.

Forming the silicone elastomer layer 208 may include at least partially curing the silicone elastomer layer 208. For example, after the silicone elastomer layer 208 is coated to a desired thickness, the silicone elastomer layer 208 may be at least partially cured, preferably fully cured. The silicone elastomer layer 208 may be cured at an ambient temperature of about 20 ℃ to about 30 ℃ and a relative humidity of about 30% to about 90% (e.g., about 40% to about 70%). The curing time may be about 24 hours at ambient temperature. In addition, or in the alternative, the silicone elastomer layer 208 may be cured at an elevated temperature of about 30 ℃ to about 70 ℃ (e.g., about 55 ℃ to about 65 ℃). In some embodiments, the silicone elastomer layer 208 is partially cured at ambient temperature before being cured at such elevated temperatures, e.g., in an oven, a heat curing chamber, or the like. For example, the silicone elastomer layer 208 may be cured first at ambient temperature (e.g., for a duration of about 2 to 6 hours) and then at an elevated temperature (e.g., for a duration of about 1 to 4 hours or, for example, about 1 to 2 hours).

At block 306, the example method 300 may include forming an abrasion-resistant layer 210 (fig. 2) at least partially covering the silicone elastomer layer 208. The wear layer 210 may be formed from a formulation as described herein, which may be applied by conventional spray or roll coating techniques, or the like. As described herein, the wear layer 210 may comprise a fiber-reinforced elastomeric material. The wear layer 210 may be applied in a series of sub-layers. The thickness of each sub-layer of the wear layer 210 may be about 100 micrometers (μm) to about 500 μm, for example about 200 μm to about 400 μm. The number of sub-layers may be determined based on the desired total thickness of the wear resistant layer 210 and the thickness of each sub-layer. For example, the exemplary wear layer 210 may include about 2 to about 40 sub-layers, such as about 5 to about 10 sub-layers, such as about 10 to about 20 sub-layers, or about 20 to about 40 sub-layers. Sequential sublayers may be applied after the solvent of the previous layer has flashed but before it has fully cured. In some embodiments, the application of the abrasion resistant layer 210 to the silicone elastomer layer 208 may begin after the silicone elastomer layer 208 is fully cured. In addition, or in the alternative, the abrasion resistant layer 210 may be applied to the silicone elastomer layer 208 before the silicone elastomer layer 208 is cured, for example, before the silicone elastomer layer 208 is fully cured. For example, a first layer of the abrasion-resistant layer 210 may be applied to a last sub-layer of the silicone elastomer layer 208 after the solvent of the silicone elastomer layer 208 has flashed off but before it has fully cured.

Forming the wear-resistant layer 210 may include at least partially curing the wear-resistant layer 210. For example, after wear layer 210 is applied to a desired thickness, wear layer 210 may be at least partially cured, preferably fully cured. In some embodiments, the abrasion-resistant layer 210 and the silicone elastomer layer 208 may be cured simultaneously, such as when the abrasion-resistant layer 210 has been coated before the silicone elastomer layer 208 is fully cured. The wear layer 210 may be cured at an ambient temperature of about 20 ℃ to about 30 ℃ and a relative humidity of about 30% to about 90% (e.g., about 40% to about 70%). The curing time may be about 24 hours at ambient temperature. In addition, or in the alternative, wear layer 210 may be cured at elevated temperatures of about 30 ℃ to about 70 ℃ (e.g., about 55 ℃ to about 65 ℃). In some embodiments, the wear layer 210 may be partially cured at ambient temperatures prior to curing at such elevated temperatures, e.g., in an oven, a heat curing chamber, etc. For example, the wear layer 210 may be cured at ambient temperature (e.g., for a duration of about 2 to 6 hours) and then at an elevated temperature (e.g., for a duration of about 1 to 4 hours or, for example, about 1 to 2 hours).

In some embodiments, wall 200 of aircraft engine component 100 may include a surface treatment 212 (FIG. 2). In addition, or in the alternative, the example method 300 may optionally include, at block 308, applying a surface treatment 212 to at least a portion of the surface 202 of the wall 200 of the component 100. The surface treatment 212 may include a chemical conversion coating and/or an anodized coating. The surface treatment 212 and/or the surface 202 of the wall 200 of the component 100 may be cleaned with a solvent-soaked clean cloth prior to applying the primer 206. The primer layer 206 may be formed in a manner to at least partially cover the surface treatment 212, wherein the surface treatment 212 is applied on the surface 202 of the wall 200 of the component 100.

The protective coating 108 may be applied to the surface 202 of the interior or exterior of the wall 200 of the component 100. The protective coating 108 may be applied to a new or refurbished component 100. In some embodiments, a preexisting coating may be removed from the component 100 prior to applying the protective coating 108 of the present application. Such preexisting coatings can be removed with water, solvents, strippers, abrasives, and the like, for example, using conventional surface treatment techniques. For example, pre-existing coatings may be removed by high pressure jets of water and/or solvent, grit blasting with a microabrasive, and/or immersion in a solution containing a solvent or stripper.

Other aspects of the present application are provided by the subject matter of the following clauses:

an aircraft engine component having:

a wall comprising an aluminum alloy and/or a magnesium alloy; and

a protective coating at least partially covering a surface of the wall;

wherein the protective coating comprises:

a primer at least partially covering the surface of the wall, the primer comprising a silane coupling agent and an organotitanate;

a silicone elastomer layer at least partially covering the primer layer, the silicone elastomer layer comprising one or more filler materials dispersed in a cross-linked silicone polymer matrix; and

an abrasion resistant layer at least partially covering the silicone elastomer layer, the abrasion resistant layer comprising a fiber reinforced elastomeric material.

The aircraft engine component of any clause herein, wherein the primer layer has a thickness of 25 to 50 microns.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer has a thickness of 1,000 to 10,000 micrometers.

The aircraft engine component according to any clause herein, wherein the wear layer has a thickness of from 150 to 500 microns.

The aircraft engine component according to any clause herein, wherein the silane coupling agent comprises a trialkoxysilane, a monoalkoxysilane, and/or a bipedal silane, preferably the silane coupling agent comprises one or more of: tetramethoxysilane, methyl silicate, tetraethoxysilane, polyethyl silicate, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, or tetrabutoxyethoxysilane.

The aircraft engine component of any clause herein, wherein the organotitanate comprises one or more of: ethyl acetoacetate titanate, diisobutyloxytitanium, di-n-butoxytitanium, diisopropoxytitanium, n-butyl polytitanium, tetra-n-butyltitanate, titanium butoxide, ethyl acetoacetate titanium or titanium tetraisopropoxide.

The aircraft engine component of any clause herein, wherein the primer coating is applied using a solution comprising: 75 to 95wt% of light aliphatic naphtha, 4 to 6wt% of tetra (2-butoxyethyl) orthosilicate and 4 to 6wt% of tetra n-butyl titanate.

The aircraft engine component of any clause herein, wherein the silicone elastomer layer comprises a one-part room temperature vulcanized silicone or a two-part room temperature vulcanized silicone.

The aircraft engine component of any clause herein, wherein the silicone elastomer layer comprises a silicone polymer derived from one or more polyorganosiloxanes, preferably the one or more polyorganosiloxanes comprise: polydimethylsiloxanes, polymethylhydrosiloxanes, dimethyldiphenylpolysiloxanes, dimethyl/methylphenylpolysiloxanes, polymethylphenylsiloxanes, methylphenyl/dimethylsiloxanes, vinyldimethyl-terminated polydimethylsiloxanes, vinylmethyl/dimethylpolysiloxanes, vinyldimethyl-terminated vinylmethyl/dimethylpolysiloxanes, divinylmethyl-terminated polydimethylsiloxanes, vinylphenylmethyl-terminated polydimethylsiloxanes, dimethylhydrogen-terminated polydimethylsiloxanes, methylhydro/dimethylpolysiloxanes, methylhydro-terminated methyloctylpolysiloxanes, methylhydro/phenylmethylpolysiloxanes and/or fluorine-modified polysiloxanes.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer comprises one or more filler materials dispersed in a cross-linked silicone polymer matrix, preferably the one or more filler materials comprise at least one of: glass microspheres, glass fibers, cenospheres, fumed silica, precipitated silica, silica fibers, silica, silicon carbide, titanium dioxide, zinc oxide, rare earth minerals, silicate minerals, inosilicates, aluminum silicates, alumina trihydrate, polyepoxide microparticles, phenolic resin microspheres, ceramics, carbon fibers, carbon black, graphene, cellulose fibers, and cork.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer comprises one or more filler materials having an average cross-sectional width of 10 nanometers to 1,000 micrometers.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer comprises a total filler content of from 1 to 90 volume percent.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer comprises a silylating agent, preferably the silylating agent comprises at least one of: aminosilanes, glycidoxysilanes, and mercaptosilanes.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer has one or more of the following properties: a thermal conductivity of 0.05W/mK to 0.15W/mK measured at 38 ℃ according to ASTM C177; a specific heat, measured according to ASTM E1269-11 2018 at 24 ℃, of from 1.0kJ/kg-K to 1.6kJ/kg-K; an ablation temperature of 450 ℃ to 600 ℃ as measured according to ASTM E285-80 2002; and 330kJ/m according to ASTM E458-08 2020 ² The heat of ablation measured at-sec heat exposure is between 40MJ/kg and 70MJ/kg.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer has one or more of the following properties: the density was 0.2g/cm ³ To 0.6g/cm ³ (ii) a And a Shore A hardness of 30 to 80 measured according to ASTM D2240-15e 1.

The aircraft engine component of any clause herein, wherein the silicone elastomer layer comprises room temperature vulcanized silicone, glass microspheres, silicone oil, fumed silica, and 3-aminopropyltriethoxysilane.

The aircraft engine component according to any clause herein, wherein the silicone elastomer layer comprises one or more of: 22 to 26wt% of one or more silicone polymers; 1 to 5wt% of silica fibers; 1 to 5wt% carbon fiber; 30 to 40wt% of silica microspheres; 4 to 8 weight percent of phenolic resin microspheres; and 20 to 40 weight percent cork.

The aircraft engine component according to any clause herein, wherein the fiber-reinforced elastomeric material of the wear layer comprises one or more silicone polymers and one or more fiber-reinforced materials, preferably the one or more fiber-reinforced materials comprise at least one of: glass fibers, basalt fibers, carbon fibers, ceramic fibers, aramid fibers, polycrystalline fibers, and/or polysiloxane fibers.

The aircraft engine component according to any clause herein, wherein the fiber-reinforced elastomeric material of the wear layer comprises at least one of: more than one thermoplastic material and more than one thermoset material.

The aircraft engine component according to any clause herein, wherein the fiber-reinforced elastomeric material of the wear layer comprises one or more thermoplastic materials, preferably the one or more thermoplastic materials comprise one or more of: acrylic, polyamide, polylactic acid, polybenzimidazole, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone, polyetherimide, polyphenylene oxide, polyphenylene sulfide, or polytetrafluoroethylene.

The aircraft engine component according to any clause herein, wherein the fiber-reinforced elastomeric material of the wear layer comprises one or more thermoset materials, preferably, the one or more thermoset materials comprise one or more of: epoxy resins, polyester resins, polyurethane or vinyl ester resins.

The aircraft engine component according to any clause herein, wherein the one or more fibrous reinforcements have an average length of 1 to 10,000 microns.

The aircraft engine component according to any clause herein, wherein the one or more fiber reinforcement materials have an average cross-sectional width of 1 μm to 50 μm.

The aircraft engine component according to any clause herein, wherein the fiber-reinforced elastomeric material comprises a total content of fiber reinforcement material from 1% to 60% by volume.

The aircraft engine component according to any clause herein, wherein the wear layer has one or more of the following properties: the density was 0.9g/cm ³ To 1.4g/cm ³ (ii) a And a Shore A hardness of 40 to 90 measured according to ASTM D2240-15e 1.

The aircraft engine component according to any clause herein, wherein the wear layer has one or more of the following properties: a thermal conductivity of 0.10W/mK to 0.25W/mK measured at 38 ℃ according to ASTM C177; a specific heat, measured according to ASTM E1269-11 2018 at 38 ℃, of from 0.9kJ/kg-K to 1.5kJ/kg-K; and an ablation temperature of 450 ℃ to 600 ℃ measured according to ASTM E285-80 2002.

The aircraft engine component according to any clause herein, wherein the wall comprises a surface treatment, preferably the surface treatment comprises a chemical conversion coating or an anodized coating.

The aircraft engine component according to any clause herein, wherein the component 100 comprises at least one of: a turbine casing, a combustor, an exhaust duct, a bypass duct, a heat exchanger, a fuel system component, an oil system component, and a firewall.

The aircraft engine component according to any clause herein, wherein the component 100 comprises at least one of: a gear box and an oil tank.

The aircraft engine component according to any clause herein, wherein the component comprises a gearbox comprising a planetary gear assembly.

A protective coating kit for applying a protective coating to an aircraft engine component, the protective coating kit comprising:

a primer layer for at least partially covering a wall of an aircraft component, the primer layer comprising a silane coupling agent and an organotitanate;

a silicone elastomer layer for at least partially covering the primer layer, the silicone elastomer layer comprising one or more filler materials dispersed in a cross-linked silicone polymer matrix; and

an abrasion resistant layer for at least partially covering the silicone elastomer layer, the abrasion resistant layer comprising a fiber reinforced elastomeric material.

A protective coating kit for applying a protective coating to an aircraft engine component, the protective coating kit comprising, after application of the protective coating to the aircraft engine component:

The protective coating kit of any clause herein, wherein the aircraft engine component and/or base coat is provided according to any clause herein.

A method of protecting an aircraft engine component from a heat source, the method comprising:

applying a primer to a wall of an aircraft engine component, the primer comprising a silane coupling agent and an organotitanate;

applying a silicone elastomer layer to the primer layer, the silicone elastomer layer comprising one or more filler materials dispersed in a cross-linked silicone polymer matrix; and

applying an abrasion resistant layer to the silicone elastomer layer, the abrasion resistant layer comprising a fiber reinforced elastomeric material.

forming a primer coating at least partially covering a surface of a wall of an aircraft engine component, the primer coating comprising a silane coupling agent and an organotitanate;

forming a silicone elastomer layer at least partially covering the primer layer, the silicone elastomer layer comprising one or more filler materials dispersed in a cross-linked silicone polymer matrix; and

forming an abrasion resistant layer at least partially covering the silicone elastomer layer, the abrasion resistant layer comprising a fiber reinforced elastomeric material.

The method according to any clause herein, wherein the aircraft engine component and/or the base coat is configured according to any clause herein.

This written description uses exemplary embodiments to describe the subject matter disclosed herein, including the best mode, to enable any person skilled in the art to practice such subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter disclosed in the present application is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. An aircraft engine component having:

a wall comprising an aluminum alloy and/or a magnesium alloy; and

a protective coating at least partially covering a surface of the wall;

wherein the protective coating comprises:

2. The aircraft engine component of claim 1, wherein the primer layer has a thickness of 25 to 50 microns.

3. The aircraft engine component of claim 1, wherein the silicone elastomer layer has a thickness of 1,000 to 10,000 micrometers.

4. The aircraft engine component of claim 1, wherein the wear resistant layer has a thickness of 150 to 500 microns.

5. The aircraft engine component of claim 1, wherein the silicone elastomer layer comprises one or more filler materials having an average cross-sectional width of 10 nanometers to 1,000 micrometers.

6. The aircraft engine component of claim 1 wherein said wall has a surface treatment comprising a chemical conversion coating or an anodized coating.

7. The aircraft engine component of claim 1, wherein the silane coupling agent comprises at least one of: trialkoxysilanes, monoalkoxysilanes and bipedal silanes.

8. The aircraft engine component of claim 1, wherein the organotitanate comprises at least one of: ethyl acetoacetate titanate, diisobutyloxytitanium, di-n-butoxytitanium, diisopropoxytitanium, n-butyl polytitanium, tetra-n-butyltitanate, titanium butoxide, titanium ethyl acetoacetate and titanium tetraisopropoxide.

9. The aircraft engine component of claim 1, wherein the primer coating is applied using a solution comprising: 75 to 95wt% of light aliphatic naphtha, 4 to 6wt% of tetra (2-butoxyethyl) orthosilicate and 4 to 6wt% of tetra n-butyl titanate.

10. The aircraft engine component of claim 1, wherein the silicone elastomer layer comprises a silicone polymer derived from one or more polyorganosiloxanes.