Multi-layer composite structure and preparation method thereof

Abstract

The invention relates to the technical field of high-temperature protection structure equipment, in particular to a multi-layer composite structure and a preparation method thereof, and the multi-layer composite structure sequentially comprises an ablation-resistant coating, a metal lining layer, a bonding layer, a ceramic layer, a transition layer, a carbon fiber composite material layer and a reinforced coating from the inner wall to the outer wall. According to the multi-layer composite structure, the advantages of all layers of materials are synergistically exerted, and the problem that light weight, high bearing capacity and high temperature resistance of an existing structure are difficult to consider is effectively solved. The ablation-resistant coating resists high-temperature fuel gas scouring, the metal lining layer guarantees high bearing capacity and air tightness, the ceramic layer achieves efficient heat insulation, the transition layer eliminates the thermal expansion matching contradiction between ceramic and the carbon fiber composite material, and interlayer cracking is avoided. The carbon fiber composite material layer greatly reduces the structural weight, and the coating is strengthened to improve the overall impact resistance. The overall structure meets the requirements for high specific strength, high toughness, high-temperature ablation resistance, heat insulation and light weight, adapts to extreme working conditions in the fields of aerospace, military affairs and the like, and is wide in application range and high in practicability.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective structure equipment technology, and in particular to a multi-layer composite structure and its preparation method. Background Technology

[0002] In the fields of aviation, aerospace, military, and high-end industry, there are numerous cylindrical or tubular structural components such as rocket engine casings, aircraft engine combustion chambers, missile bodies, and artillery barrels. These components not only withstand extremely high internal pressure or axial loads, but their inner walls also face thermal shock from high-temperature combustion gases or high-speed airflows. This operating condition places extremely stringent requirements on structural materials, requiring them to meet high specific strength and specific stiffness to achieve lightweighting, while also possessing long-term high-temperature resistance, ablation resistance, and thermal insulation properties.

[0003] Existing technologies typically employ pure metal structures or simple composite structures, which have significant shortcomings. While pure metal structures offer strong load-bearing capacity, their high density hinders weight reduction. Carbon / carbon composite or ceramic matrix composite shells possess high-temperature resistance and low density, but suffer from poor toughness, insufficient impact resistance, and oxidation issues at high temperatures. Although metal-carbon fiber composite structures reduce overall weight, the carbon fiber composite matrix is ​​also prone to oxidation at high temperatures. Therefore, there is an urgent need for a new type of multilayer composite structure that can combine the high toughness and high load-bearing capacity of metals, the high specific strength of carbon fiber composites, and the efficient thermal protection capabilities of advanced thermal barrier coating systems, to overcome the limitations of the above materials and meet the requirements of lightweight, high load-bearing capacity, and efficient thermal protection. Summary of the Invention

[0004] The purpose of this invention is to provide a multilayer composite structure and its preparation method, which can solve the above-mentioned technical problems.

[0005] This invention provides a multi-layer composite structure, comprising, from the inner wall to the outer wall, a resistant ablation coating, a metal liner, an adhesive layer, a ceramic layer, a transition layer, a carbon fiber composite material layer, and a reinforcing coating. The resistant ablation coating is composed of silicon-based, carbon-based, or ceramic-based materials and is sprayed onto the inner surface of the metal liner. The metal liner is a load-bearing structure and an airtight layer made of a high-temperature alloy. The adhesive layer is an MCrAlY alloy material, where M is Ni, Co, or NiCo. The ceramic layer is composed of rare-earth oxide-stabilized zirconium oxide, rare-earth zirconate, or a combination of both. The transition layer is a graded functional material with a thermal expansion coefficient between that of the ceramic layer and the carbon fiber composite material layer. The carbon fiber composite material layer is composed of carbon fibers and a high-temperature resistant resin matrix, wound and cured on the outer side of the transition layer. The reinforcing coating is a high-toughness polymer coating disposed on the outer surface of the carbon fiber composite material layer.

[0006] The aforementioned ablation-resistant coating is sprayed onto the inner surface of the metal-lined cylinder. It absorbs and carries away a large amount of heat through its own physicochemical changes under high-temperature conditions, protecting the underlying metal structure. The metal lining layer, serving as the load-bearing main body and airtight layer, is made of high-strength, high-toughness metal materials such as titanium alloy, nickel alloy, or other high-temperature alloys, providing the main rigidity and strength of the structure. The adhesive layer is sprayed onto the outer surface of the metal-lined cylinder, primarily to enhance the adhesion between the outer ceramic layer and the metal substrate, and to alleviate thermal stress caused by the mismatch in thermal expansion coefficients between the metal and ceramic. The ceramic layer is sprayed on top of the adhesive layer, serving as the main heat insulation layer, utilizing its low thermal conductivity. The system effectively blocks heat transfer to the outer layer; the transition layer, fabricated on top of the ceramic layer, is composed of graded functional materials with a thermal expansion coefficient between that of the ceramic layer and the outer carbon fiber composite material, used to match the difference in thermal expansion coefficients between the two and prevent excessive temperature difference from causing interface cracking; the carbon fiber composite material layer is the main load-bearing structure, providing high specific strength and specific stiffness to achieve overall structural lightweighting and enhance the load-bearing capacity of the structure; the reinforcing coating is sprayed on the outer surface of the carbon fiber composite material layer, mainly to prevent damage to the carbon fiber composite material layer from external environmental factors such as humidity, corrosion, and mechanical scratches, and to withstand some pressure or impact using its high toughness.

[0007] Preferably, the transition layer is a metal-ceramic graded functional material, wherein the metal phase is Ni, Co, or their alloys, and the ceramic phase is zirconium oxide or rare earth zirconate. The volume fraction of the metal phase in the graded functional material gradually changes from 20-40% near the ceramic layer side to 60-80% near the carbon fiber composite side.

[0008] Preferably, the high-temperature resistant resin matrix is ​​one or more combinations of high-temperature resistant epoxy resin, polyimide, or bismaleimide. The glass transition temperature of the high-temperature resistant epoxy resin is not lower than 180°C, and the long-term service temperature of the polyimide is not lower than 280°C.

[0009] Preferably, the reinforcing coating is a polyurea coating or a high-toughness polyurethane coating. The elongation at break of the polyurea coating is not less than 300%, and the elongation at break of the polyurethane coating is not less than 250%.

[0010] Preferably, the thickness of the ablation-resistant coating is 0.1-0.5 mm, and it is prepared by internal atmospheric plasma spraying or internal supersonic flame spraying.

[0011] Preferably, the thickness of the metal liner is 2-10 mm, and the metal liner is heat-treated before the preparation of the multilayer composite structure.

[0012] Preferably, the thickness of the adhesive layer is 50-200 μm, and the thickness of the ceramic layer is 0.2-1.0 mm, both of which are prepared by atmospheric plasma spraying or supersonic flame spraying.

[0013] Preferably, the transition layer has a thickness of 0.1-0.5 mm and is prepared by atmospheric plasma spraying.

[0014] Preferably, the carbon fiber composite material layer has a thickness of 2-10 mm, the reinforcing coating has a thickness of 0.05-0.3 mm, and is prepared by spraying or brushing and cured at room temperature or by heating.

[0015] The present invention also provides a method for preparing the above-mentioned multilayer composite structure, comprising the following steps: Metal liner pretreatment: The inner and outer surfaces of the metal liner are cleaned and roughened by sandblasting to obtain a clean, active surface with a specific roughness. After pretreatment, the surface roughness Ra is 2.0-4.0 μm and Rz is 15-25 μm.

[0016] Spraying an ablation-resistant coating: An ablation-resistant coating is sprayed onto the inner surface of the metal lining using an internal atmospheric plasma spraying or internal supersonic flame spraying process.

[0017] Thermal barrier coating: On the outer surface of the metal liner, an MCrAlY bonding layer is first sprayed using atmospheric plasma spraying or supersonic flame spraying, and then a ceramic layer is sprayed on the bonding layer to form a bonding layer and a ceramic layer.

[0018] Preparation of transition layer: A transition material, such as a metal-ceramic gradient functional material or a modified ceramic layer, is sprayed onto the ceramic layer using an atmospheric plasma spraying process.

[0019] Carbon fiber composite layer forming: The wet winding process is used to wind resin-impregnated carbon fiber bundles around the outside of the component that has completed the above steps at a preset angle (the preset angle is ±28.7°-90°). After winding, the component is placed in a curing oven for heating and pressure curing to allow the resin to cross-link and form a dense carbon fiber composite layer.

[0020] A high-toughness polymer coating is sprayed or brushed onto the outer surface of the cured carbon fiber composite layer to form a reinforcing coating, and then cured at room temperature or by heating.

[0021] Beneficial effects: This invention utilizes a multi-layered composite structure that synergistically leverages the advantages of each layer's materials, effectively addressing the challenge of balancing lightweight design with high load-bearing capacity and high-temperature resistance in existing structures. An ablation-resistant coating resists the erosion of high-temperature combustion gases, a metal liner ensures strong load-bearing capacity and airtightness, a ceramic layer provides efficient thermal insulation, and a transition layer eliminates the thermal expansion mismatch between the ceramic and carbon fiber composite materials, preventing interlayer cracking. The carbon fiber composite layer significantly reduces structural weight, while a reinforcing coating enhances overall impact resistance and solves the problem of high-temperature oxidation of carbon fibers. The overall structure balances high specific strength, high toughness, high-temperature ablation resistance, thermal insulation, and lightweight requirements, making it suitable for extreme operating conditions in aerospace, military, and other fields. It has a wide range of applications and strong practicality. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 In this invention Figure 1 Enlarged schematic diagram of the structure at point A; Figure 3 This is a schematic diagram of the multilayer composite cylindrical structure prepared according to the present invention.

[0024] Explanation of reference numerals in the attached drawings: 1-Composite cylindrical shell / cylindrical structure, 2-Ablation resistant coating, 3-Metallic inner lining layer, 4-Adhesive layer, 5-Ceramic layer, 6-Transition layer, 7-Carbon fiber composite material layer, 8-Reinforcing coating. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] This invention provides a lightweight, high-load-bearing composite cylindrical shell or cylindrical structure applicable to high-temperature and high-pressure environments, suitable for fields such as aerospace propulsion systems, thermal protection of hypersonic vehicles, and weapon system tubes.

[0029] like Figure 1 and 2 As shown, the composite cylindrical shell / cylindrical structure 1 includes, from the inner wall to the outer wall, an ablation-resistant coating 2, a metal liner 3, an adhesive layer 4, a ceramic layer 5, a transition layer 6, a carbon fiber composite material layer 7, and a reinforcing coating 8. Detailed descriptions are provided below using several embodiments.

[0030] Example 1 Multi-layer composite structure: Ablation-resistant coating: Silicon-based ablation material, specifically a silicone rubber matrix containing SiC or ZrSi2, with a thickness of 0.1 mm and a porosity of 3%; Metal inner lining: 30CrMnSiA alloy steel, 2mm thick; and the 30CrMnSiA alloy steel is heat treated, the specific process is as follows: quenching + tempering, oil quenching at 880℃ + tempering at 540℃.

[0031] Adhesive layer: NiCoCrAlY alloy, 120μm thick; Ceramic layer: 8YSZ (8% yttrium oxide stabilized zirconia), thickness 0.2mm; Transition layer: Ni-8YSZ graded functional material, 0.1 mm thick; the volume fraction of the metallic phase in the graded functional material gradually changes from 30% near the ceramic layer to 70% near the carbon fiber composite material. Carbon fiber composite layer: The carbon fiber is M46, the resin matrix is ​​high-temperature resistant epoxy resin, the winding angle is ±45°, the thickness is 2mm, and the fiber volume fraction is 60%. Reinforced coating: Polyurea coating, 0.1 mm thick, Shore hardness D65, elongation at break 350%.

[0032] Preparation method: Metal lining pretreatment: Surface roughness Ra = 2.5 μm after sandblasting; Erosion-resistant coating spraying: atmospheric plasma spraying, power 45kW, spraying distance 120mm; Thermal barrier coating spraying: atmospheric plasma spraying, power 45kW, spraying distance 120mm; Transition layer preparation: atmospheric plasma spraying, power 40kW, spraying distance 120mm; Curing of carbon fiber composite layer: temperature 150℃, pressure 0.6MPa, heat preservation for 4h; Curing of reinforced coating: Temperature 80℃, curing time 2h.

[0033] Example 2 Multi-layer composite structure: Ablation-resistant coating: carbon-based ablation material, specifically carbon-phenolic composite material, with a thickness of 0.15 mm and a porosity of 4%.

[0034] Metal lining: TC11 titanium alloy, 2mm thick; and the TC11 titanium alloy is heat-treated, specifically by double annealing, first annealing at 950℃ / 1h / WQ + second annealing at 530℃ / 6h / AC. Adhesive layer: CoCrAlY alloy, 150μm thick; Ceramic layer: La2Zr2O7 (lanthanum zirconate), thickness 0.25mm; Transition layer: Co-La2Zr2O7 graded functional material, 0.12 mm thick; the volume fraction of the metallic phase in the graded functional material gradually changes from 20% near the ceramic layer to 80% near the carbon fiber composite material. Carbon fiber composite layer: The carbon fiber is M46, the resin matrix is ​​polyimide, the winding angle is ±15°+±60°, the thickness is 2mm, and the fiber volume fraction is 65%; Reinforced coating: High-toughness polyurethane coating, 0.06mm thick, Shore hardness D70, elongation at break 320%.

[0035] Preparation method: Metal lining pretreatment: Surface roughness Ra = 3.0 μm after sandblasting; Ablation-resistant coating spraying: Supersonic flame spraying, power 55kW, spraying distance 100mm; Thermal barrier coating spraying: supersonic flame spraying, power 55kW, spraying distance 100mm; Transition layer preparation: atmospheric plasma spraying, power 45kW, spraying distance 110mm; Curing of carbon fiber composite layer: temperature 180℃, pressure 0.8MPa, heat preservation for 6h; Curing of reinforced coating: Temperature 100℃, curing time 3h.

[0036] Example 3 Multi-layer composite structure: Ablation-resistant coating: ceramic-based ablation material (Al2O3-30wt%SiC), thickness 0.12mm, porosity 2%; Metal lining: Inconel 718 nickel alloy, 2mm thick; and the Inconel 718 nickel alloy is heat treated, specifically solution treatment + aging, solution treatment 1020℃ / 1h / WQ + aging 780℃ / 8h / AC.

[0037] Adhesive layer: NiCrAlY alloy, 100μm thick; Ceramic layer: 8YSZ+La2Zr2O7 composite ceramic, thickness 0.22mm; Transition layer: NiCo-8YSZ+La2Zr2O7 composite gradient material, 0.1 mm thick; the volume fraction of the metallic phase in the gradient functional material gradually changes from 40% near the ceramic layer to 60% near the carbon fiber composite material. Carbon fiber composite layer: carbon fiber is M46, resin matrix is ​​bismaleimide, winding angle is ±30°+±45°, thickness is 2mm, fiber volume fraction is 62%; Reinforced coating: Polyurea coating, 0.1 mm thick, Shore hardness D62, elongation at break 380%.

[0038] Preparation method: Metal lining pretreatment: Surface roughness Ra = 2.0 μm after sandblasting; Ablation-resistant coating spraying: atmospheric plasma spraying, power 40kW, spraying distance 130mm; Thermal barrier coating spraying: atmospheric plasma spraying, power 40kW, spraying distance 130mm; Transition layer preparation: atmospheric plasma spraying, power 38kW, spraying distance 130mm; Carbon fiber composite layer curing: temperature 160℃, pressure 0.5MPa, heat preservation for 5h; Reinforced coating curing: Curing at room temperature for 4 hours.

[0039] Performance testing: Multiple cylindrical structures are prepared using the methods described in Examples 1-3 above, such as... Figure 3 As shown, the length is 500mm and the inner diameter is 80mm; The cylindrical structures prepared in Examples 1-3 were tested under the same conditions, and the results are as follows:

[0040] The above comparative example is a cylindrical structure of 30CrMnSi alloy steel with a thickness of 4.5mm, a length of 500mm, and an inner diameter of 80mm, which was prepared separately.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multilayer composite structure, characterized in that, The structure, from inner to outer wall, comprises an ablation-resistant coating, a metal liner, an adhesive layer, a ceramic layer, a transition layer, a carbon fiber composite layer, and a reinforcing coating. The ablation-resistant coating, composed of silicon-based, carbon-based, or ceramic-based materials, is sprayed onto the inner surface of the metal liner. The metal liner serves as both a load-bearing structure and an airtight layer, made of a high-temperature alloy. The adhesive layer is an MCrAlY alloy, where M represents Ni, Co, or NiCo. The ceramic layer is composed of rare-earth oxide-stabilized zirconium oxide, rare-earth zirconates, or a combination of both. The transition layer is a graded functional material with a thermal expansion coefficient between that of the ceramic layer and the carbon fiber composite layer, used to eliminate interlayer stress caused by the mismatch in thermal expansion coefficients. The carbon fiber composite layer, composed of carbon fibers and a high-temperature resistant resin matrix, is wound and cured onto the outer side of the transition layer. The reinforcing coating is a high-toughness polymer coating that coats the outer side of the carbon fiber composite layer, improving impact resistance.

2. The multilayer composite structure according to claim 1, characterized in that, The transition layer is a metal-ceramic gradient functional material, wherein the metal phase is Ni, Co or their alloys, and the ceramic phase is zirconium oxide or rare earth zirconate; in the gradient functional material, the volume fraction of the metal phase gradually changes from 20-40% near the ceramic layer to 60-80% near the carbon fiber composite layer.

3. The multilayer composite structure according to claim 1, characterized in that, The high-temperature resistant resin matrix is ​​one or more combinations of high-temperature resistant epoxy resin, polyimide, or bismaleimide; the glass transition temperature Tg of the high-temperature resistant epoxy resin is ≥180℃, and the long-term service temperature of the polyimide is ≥280℃.

4. The multilayer composite structure according to claim 1, characterized in that, The reinforcing coating is a polyurea coating or a high-toughness polyurethane coating; the elongation at break of the polyurea coating is ≥300%, and the elongation at break of the polyurethane coating is ≥250%.

5. The multilayer composite structure according to claim 1, characterized in that, The thickness of the ablation-resistant coating is 3%-10% of the thickness of the metal liner, and it is prepared by internal atmospheric plasma spraying or internal supersonic flame spraying.

6. The multilayer composite structure according to claim 1, characterized in that, The thickness of the metal liner is not limited, and the metal liner is heat-treated before the preparation of the multilayer composite structure.

7. The multilayer composite structure according to claim 1, characterized in that, The thickness of the adhesive layer is 50-200 μm, and the thickness of the ceramic layer is 8%-20% of the thickness of the metal liner layer. Both are prepared by atmospheric plasma spraying or supersonic flame spraying.

8. The multilayer composite structure according to claim 1, characterized in that, The transition layer has a thickness of 3%-8% of the metal liner thickness and is prepared by atmospheric plasma spraying.

9. The multilayer composite structure according to claim 1, characterized in that, The thickness of the carbon fiber composite layer is 60%-250% of the thickness of the metal liner layer, and the thickness of the reinforcing coating is 1%-8% of the thickness of the metal liner layer. It is prepared by spraying or brushing and cured at room temperature or by heating.

10. A method for preparing a multilayer composite structure according to any one of claims 1-9, characterized in that, Includes the following steps: Metal lining pretreatment: The inner and outer surfaces of the metal lining are cleaned and roughened by sandblasting to obtain a clean, active surface with a specific roughness; Spraying an ablation-resistant coating: Using an internal atmospheric plasma spraying or internal supersonic flame spraying process, an ablation-resistant coating is sprayed onto the inner surface of the metal lining layer. Thermal barrier coating: On the outer surface of the metal liner, an MCrAlY bonding layer is first sprayed using atmospheric plasma spraying or supersonic flame spraying, and then a ceramic layer is sprayed on the bonding layer to form a bonding layer and a ceramic layer. Preparation of transition layer: A transition material, such as a metal-ceramic gradient functional material or a modified ceramic layer, is sprayed onto the ceramic layer using an atmospheric plasma spraying process. Carbon fiber composite layer forming: The wet winding process is used to wind resin-impregnated carbon fiber bundles around the outside of the component that has completed the above steps at a preset angle. After winding, the component is placed in a curing oven for heating and pressure curing to allow the resin to cross-link and form a dense carbon fiber composite layer. A high-toughness polymer coating is sprayed or brushed onto the outer surface of the cured carbon fiber composite layer to form a reinforcing coating, and then cured at room temperature or by heating.

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