A metallized fiber-reinforced ceramic matrix composite material and a preparation method thereof

Abstract

The present invention provides a metallized fiber-reinforced ceramic matrix composite material and a preparation method thereof, belonging to the field of ceramic matrix composite materials. The preparation method of the metallized fiber-reinforced ceramic matrix composite material comprises the following steps: substrate pretreatment, preparation of a composite reinforcing powder, preparation of an interface layer, preparation of a metal layer, and finishing. The metallized fiber-reinforced ceramic matrix composite material and the preparation method thereof of the present invention can effectively overcome the problems that the existing metallization methods are not applicable to the preparation of conformal antennas for fiber-reinforced ceramic matrix composite materials, as well as overcome the problems of complex metallization processes and strong equipment dependence, improve the bonding performance between the metallized layer and the fiber-reinforced ceramic matrix composite material, and improve the coating stability.

Description

Technical Field

[0001] The present invention relates to the field of ceramic matrix composites, and in particular to a metallized fiber-reinforced ceramic matrix composite and a preparation method thereof. Background Art

[0002] With the continuous development of aircraft guidance technology, in the composite guidance mode, as an important part of the passive radar seeker, the passive antenna is required to have good impedance matching and radiation characteristics in an ultra-wide frequency band on the premise of occupying as little space of the aircraft as possible, and be conformal with the aircraft in structure. Therefore, the conformal antenna came into being. A conformal antenna refers to a radiation antenna attached to and conforming to the surface of an aircraft, and is usually installed on high-speed aircraft platforms such as airplanes, missiles, and satellites. The conformal antenna has the characteristics of not destroying the external structure and aerodynamics of the aircraft, and is one of the research hotspots in the field of aircraft antennas.

[0003] Specifically, a conformal antenna generally integrates a radiation antenna with a ceramic cover (window) of an aircraft, and has the characteristics of miniaturization, flexible installation, and easy feeding. It can also effectively solve the problems of insufficient direction-finding distance and angle existing in the current buried passive antenna. Currently, most of the passive antenna covers (windows) are fiber-reinforced ceramic matrix composites, and the key to the conformal antenna preparation technology lies in the good combination of the metal radiation unit (metal layer) and the fiber-reinforced ceramic matrix composite to meet the requirements of aerodynamic heat environment tolerance and welding.

[0004] After investigation, in the preparation of existing conformal antennas, the methods for metallization on the surface of ceramic materials mainly include: thin film method, thick film method, direct copper plating method, laser technology, etc. The thin film method is divided into chemical plating, physical vapor deposition, chemical vapor deposition, vacuum ion plating (including magnetron sputtering, cathodic arc ion plating), etc. The coating is relatively thin and is generally used for the preparation of electrode materials. The thick film method mainly includes screen printing, inkjet printing and other technologies. The direct copper plating method (DBC) is mainly for the metallization technology of alumina, beryllia, and aluminum nitride substrates.

[0005] However, the existing metallization methods, whether it is chemical plating or physical vapor deposition / chemical vapor deposition, etc., have limitations in the metallization process of the aforementioned fiber-reinforced ceramic matrix composites: First, the above methods are only relatively mature for homogeneous ceramic materials. When using fiber-reinforced ceramic matrix composites as the matrix, there is a problem of insufficient bonding performance between the metal layer and the matrix material; Second, the existing metallization processes are relatively complex, highly dependent on equipment, and have high requirements for the surface and shape of the matrix material. Therefore, the existing metallization methods are not suitable for the preparation of conformal antennas for fiber-reinforced ceramic matrix composites.

[0006] Chinese Patent CN112552079A discloses that silver paste (or palladium-silver paste) is directly and evenly coated onto the surface of SiO2f / SiO2 composite material using a curved surface coater, and then the desired metallized curved substrate is obtained after sintering at 750°C. However, the bonding strength between the metal layer and the matrix material in the obtained metallized SiO2f / SiO2 composite material is not good.

[0007] Chinese Patent CN109704796A discloses a method for preparing a frequency selective wave-transparent material by forming a sandwich structure using 2D or 2.5D fabric sheets and FSS structural units. The main steps are as follows: after impregnating the fabric sheet with silica sol and drying it to form a prepreg, it is sequentially overlapped with an organic film having an FSS structure to form a combined blank of a sandwich structure, and finally, the whole is impregnated with silica sol, dried, formed, and sintered to obtain a product with an FSS structure between low-density layers. However, due to the limitations of this process, it is difficult to control the alignment accuracy between metal layers, especially for complex structures such as arc surfaces, resulting in the inability to effectively guarantee its related performance and making it inapplicable to the preparation of conformal antennas with special-shaped structures.

[0008] Chinese Patent CN106630979A discloses a method for preparing a metallized layer on a fiber-reinforced ceramic composite material. First, a modification layer (such as quartz glass, lithium aluminosilicate, barium aluminosilicate, cordierite, etc.) is prepared on the surface of the composite material using a plasma spraying process, and then a metallized surface layer is prepared by physical sputtering or slurry method. However, to improve the bonding performance between the metallized layer and the matrix material, the required modification layer is relatively thick (about 100μm), which is prone to cracking on special-shaped products or large-sized products, and the stability is not good; moreover, the preparation process still relies on plasma spraying equipment, resulting in high production costs.

[0009] Therefore, aiming at the problems that the existing metallization methods are not applicable to the preparation of conformal antennas for fiber-reinforced ceramic matrix composites, as well as the problems of complex metallization processes and strong equipment dependence, a metallization method that is effectively applicable to conformal antennas for fiber-reinforced ceramic matrix composites is specifically provided, which improves the bonding performance between the metallized layer and the fiber-reinforced ceramic matrix composite material and improves the coating stability. It has important technical significance and research value, providing technical support for the further research and development and expansion of conformal antennas. Summary of the Invention

[0010] To solve the technical problems existing in the prior art, the present invention provides a metallized fiber-reinforced ceramic matrix composite material and a preparation method thereof, effectively overcoming the problems that the existing metallization methods are not applicable to the preparation of conformal antennas for fiber-reinforced ceramic matrix composites, as well as overcoming the problems of complex metallization processes and strong equipment dependence, improving the bonding performance between the metallized layer and the fiber-reinforced ceramic matrix composite material, and improving the coating stability.

[0011] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0012] A preparation method of a metallized fiber-reinforced ceramic matrix composite material includes the following steps: substrate pretreatment, preparation of a composite reinforcing powder, preparation of an interface layer, preparation of a metal layer, and finishing machining;

[0013] For the substrate pretreatment, the fiber-reinforced ceramic matrix composite material is processed to the predetermined size of the conformal antenna, and then after surface polishing and defect repair, a pretreated substrate is obtained;

[0014] For the preparation of the composite reinforcing powder, nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder are mixed evenly to obtain a premixed powder; after the premixed powder is treated with a silane coupling agent APTES, a composite reinforcing powder is obtained;

[0015] For the preparation of the interface layer, an interface layer spray coating slurry is obtained by mixing an interface layer coating, a solvent, and the composite reinforcing powder evenly; after the interface layer spray coating slurry is sprayed onto the surface of the pretreated substrate, it is dried and sintered to obtain a substrate with an interface layer formed on its surface;

[0016] The interface layer coating is a polysilazane coating or a polysiloxane coating;

[0017] For the preparation of the metal layer, a metallized spray coating slurry is sprayed onto the surface of the interface layer of the substrate, and then after drying and sintering, a substrate with a metal layer formed on its surface is obtained.

[0018] Further, in the substrate pretreatment, the defect repair is carried out by spot coating the defect with a repair liquid and then sintering;

[0019] The repair liquid is composed of the following raw materials in parts by weight: 35-45 parts of silica sol, 1-5 parts of boric acid, and 55-65 parts of submicron ceramic powder;

[0020] The submicron ceramic powder is selected from: silicon oxide, alumina, and mullite.

[0021] Further, in the preparation of the composite reinforcing powder, the premixed powder is put into an ethanol solution, stirred and heated to 55-60 °C, kept warm and the silane coupling agent APTES is dropped in; after the dropping of the silane coupling agent APTES is completed, continue to keep warm and stir for 4-5 h, then separate to obtain a solid, and the solid is washed with water and dried to obtain a composite reinforcing powder.

[0022] Preferably, in the preparation of the composite reinforcing powder, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3-3.5:5-6:1-1.2;

[0023] The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.2-0.25.

[0024] Preferably, in the preparation of the interface layer, the mass ratio of the interface layer coating, the solvent, and the composite reinforcing powder is 84-88:32-40:12-16;

[0025] The spraying pressure of the interface layer spraying coating slurry is 0.2-0.3 MPa, and the spraying weight gain is controlled to be 0.4-0.6 g for every 100 cm of the surface of the pre-treated substrate. 2 The spraying weight of the surface of the pre-treated substrate is 0.4-0.6 g.

[0026] Preferably, in the preparation of the interface layer, the drying temperature is 85-100 °C, and the drying time is 0.5-1 h;

[0027] The sintering temperature is 750-850 °C, and the sintering time is 15-30 min;

[0028] The thickness of the interface layer is 6-10 μm.

[0029] Preferably, in the preparation of the metal layer, the metallized spraying coating slurry contains a metal slurry and a diluent;

[0030] The metal slurry is one of the following: silver slurry, gold slurry, platinum slurry, silver-palladium alloy slurry;

[0031] The diluent is an ethanol or propanol solution of butyl carbitol or terpineol;

[0032] The mass ratio of the metal slurry to the diluent is 65-75:25-35.

[0033] Preferably, in the preparation of the metal layer, the spraying pressure of the metallized spraying coating slurry is 0.2-0.3 MPa, and the spraying weight gain is controlled to be 1-1.5 g for every 100 cm of the surface of the interface layer; 2 The spraying weight of the surface of the interface layer is 1-1.5 g;

[0034] The drying temperature is 120-150 °C, and the drying time is 0.5-1 h;

[0035] The sintering temperature is 750-850 °C, and the sintering time is 10-15 min;

[0036] The thickness of the metal layer is 8-15 μm.

[0037] Furthermore, for the finish machining, laser etching is used to finish machine the metal layer in the conformal antenna radiation area to obtain a metallized fiber-reinforced ceramic matrix composite material for the conformal antenna;

[0038] The laser etching uses a 3D galvanometer to control the laser direction and performs etching with picosecond laser;

[0039] The laser power of the laser etching is 2-5 W, the linear velocity is 300-500 mm / s, and the etching times are 2-4 times.

[0040] A metallized fiber-reinforced ceramic matrix composite prepared by the aforementioned method.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) In the preparation method of the metallized fiber-reinforced ceramic matrix composite of the present invention, the fiber-reinforced ceramic matrix composite is processed into a predetermined size of a conformal antenna cover (window) as required. After obtaining a pretreated substrate, nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder are mixed evenly and treated with a silane coupling agent APTES to obtain a composite reinforcing powder. Through the modification treatment of the premixed powder by the silane coupling agent APTES, while improving its dispersibility in the interface layer spray coating slurry, its bonding performance with the interface layer coating is improved. Then, the composite reinforcing powder is mixed with the interface layer coating (polysilazane coating or polysiloxane coating) to obtain an interface layer spray coating slurry, which is then sprayed onto the surface of the pretreated substrate to form an interface layer; and by adding the composite reinforcing powder, shrinkage is inhibited, internal stress is reduced, the thermal stability, thermal shock resistance, and mechanical properties of the interface layer are improved; and the bonding performance between the interface layer and the matrix is improved, and a mechanical interlock is formed through the anchoring effect of the composite reinforcing powder on the surface of the pretreated substrate to inhibit interface peeling; meanwhile, through the setting of the interface layer, the wetting problem between the metal layer and the composite material is effectively improved, and the bonding performance between the coating and the substrate is optimized. Then, the metallized spray coating slurry is coated on the interface layer coating area to form a metal layer, and finally, after precision machining, a metallized fiber-reinforced ceramic matrix composite is obtained; the above-mentioned various technical means cooperate with each other and act synergistically, which can effectively overcome the problem that the existing metallization method is not applicable to the preparation of conformal antennas for fiber-reinforced ceramic matrix composites, and overcome the problems of complex metallization process and strong equipment dependence, improve the bonding performance between the metallized layer and the fiber-reinforced ceramic matrix composite, and improve the coating stability.

[0043] (2) In the preparation method of the metallized fiber-reinforced ceramic matrix composite of the present invention, an interface layer is formed on the surface of the fiber-reinforced ceramic matrix composite by means of precursor ceramization conversion. The preparation method is simple and the bonding force is better; at the same time, the ceramization reaction can cure and strengthen the fiber bundles exposed on the surface of the fiber-reinforced ceramic matrix composite, further optimizing the bonding performance between the coating and the substrate.

[0044] (3)The preparation method of the metallized fiber-reinforced ceramic matrix composite material of the present invention has strong process applicability. By selecting the interface layer material and the metal layer material, a coating with specific temperature resistance performance can be prepared on the surface of different ceramic matrix composite materials, providing a technical option for the subsequent research and development of conformal antennas. Moreover, the preparation method of the present invention is simple, with easy operation and low equipment requirements. It can be prepared using traditional cold spraying equipment and muffle furnace sintering equipment, without the need for complex process equipment, which is conducive to large-scale industrial production. Specific Embodiments

[0045] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention are now described. It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, "first", "second", etc. are used to distinguish similar objects and are not used to describe a specific order or sequence. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] The embodiment of the present invention provides a preparation method of a metallized fiber-reinforced ceramic matrix composite material, which is achieved through the following technical solutions: First, the fiber-reinforced ceramic matrix composite material is processed to the design size of the conformal antenna cover (window) as required. Then, the interface layer spray coating slurry is coated on the metal radiation area required by the antenna by spraying, and the fiber-reinforced ceramic matrix composite material with an interface layer is obtained after drying and sintering. Again, the metallized spray coating slurry is coated on the interface layer coating area by spraying, and the metallized fiber-reinforced ceramic matrix composite material is obtained after drying and sintering. Finally, according to the requirements of the conformal antenna, the obtained metallized fiber-reinforced ceramic matrix composite material is finely processed for the antenna radiation unit by laser processing, and finally, the metallized fiber-reinforced ceramic matrix composite material (such as conformal antenna cover, window, etc.) that can be used for the conformal antenna is obtained.

[0048] The preparation method of the metallized fiber-reinforced ceramic matrix composite material includes the following steps: substrate pretreatment, preparation of composite reinforcing powder, preparation of interface layer, preparation of metal layer, and finishing.

[0049] The method for pre-treating the substrate is as follows: according to the requirements of the conformal antenna for heat resistance performance, dielectric performance, and mechanical performance, a fiber-reinforced ceramic matrix composite is selected; the fiber-reinforced ceramic matrix composite is processed to the predetermined size of the conformal antenna, and then its surface is polished and defect repaired. After that, the non-working area is shielded and protected with paper tape to obtain the pre-treated substrate.

[0050] In the pre-treatment of the substrate, the fiber-reinforced ceramic matrix composites are all existing ceramic matrix composites, including: quartz fiber-reinforced quartz composite, quartz fiber-reinforced silicon nitride composite, alumina fiber-reinforced alumina composite, and mullite fiber-reinforced alumina composite.

[0051] The polishing is to polish the surface of the fiber-reinforced ceramic matrix composite with 800-1000 mesh sandpaper to remove the fiber burrs on the material surface caused by machining; the defect repair is to apply a repair liquid to the defect points, and then keep it warm and sinter at 650-750 °C for 1-2 h to repair the indentations and material shortages caused by fiber breakage and peeling on the material surface due to machining.

[0052] The repair liquid is composed of silica sol, boric acid, and submicron ceramic powder; the submicron ceramic powder is selected from silicon oxide, alumina, and mullite. The mass dosage of each raw material in the repair liquid is: 35-45 parts of silica sol, 1-5 parts of boric acid, and 55-65 parts of submicron ceramic powder.

[0053] The method for preparing the composite reinforcing powder is as follows: put nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder into a ball mill, control the ball-to-material-water ratio to be 6-6.5:1:0.6-0.7, the ball milling speed to be 120-180 rpm, and after ball milling for 20-30 min, take out the ball milled material and dry it to obtain the premixed powder; then put the premixed powder into an ethanol solution (volume concentration 70-75%) with a mass 5-6 times that of the premixed powder, heat it to 55-60 °C under the stirring condition of 50-80 rpm, keep it warm and drop in the silane coupling agent APTES; after the dropping of the silane coupling agent APTES is completed, continue to keep it warm and stir for 4-5 h, then filter to obtain the solid, and the solid is washed with water and dried to obtain the composite reinforcing powder.

[0054] In the preparation of the composite reinforcing powder, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3-3.5:5-6:1-1.2;

[0055] The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.2-0.25.

[0056] The method for preparing the interface layer is as follows: uniformly mix the interface layer coating material, solvent, and composite reinforcing powder to obtain the interface layer spray coating slurry; by means of spraying, under the condition that the spraying pressure is 0.2 - 0.3 MPa, use a spray gun to spray the interface layer spray coating slurry onto the surface of the pretreated substrate, and control the spraying weight gain (the spraying amount on the surface of the pretreated substrate is 0.4 - 0.6 g per 100 cm 2 After spraying, place it in an oven and dry it at 85 - 100 °C for 0.5 - 1 h, then transfer it to a muffle furnace and sinter it at 750 - 850 °C for 15 - 30 min to cause the ceramic conversion of the interface layer material, and obtain a substrate with an interface layer formed on its surface, and the thickness of the interface layer is 6 - 10 μm.

[0057] In the preparation of the interface layer, the interface layer coating material is a polysilazane coating material or a polysiloxane coating material; the solvent is toluene or xylene;

[0058] The mass ratio of the interface layer coating material, solvent, and composite reinforcing powder is 84 - 88:32 - 40:12 - 16;

[0059] The optional models of the spray gun used for spraying are existing atomizing spray guns of W - 71, W - 77, W - 101, and W - 201.

[0060] The method for preparing the metal layer is as follows: uniformly mix the metal slurry and the diluent to obtain the metallized spray coating slurry; by means of spraying, under the condition that the spraying pressure is 0.2 - 0.3 MPa, use a spray gun to spray the metallized spray coating slurry onto the surface of the interface layer of the substrate, and control the spraying weight gain (the spraying amount on the surface of the pretreated substrate is 1 - 1.5 g per 100 cm 2 After spraying, place it in an oven and dry it at 120 - 150 °C for 0.5 - 1 h, then transfer it to a muffle furnace and sinter it at 750 - 850 °C for 10 - 15 min to obtain a substrate with a metal layer formed on its surface, and the thickness of the metal layer is 8 - 15 μm.

[0061] In the preparation of the metal layer, the metal slurry is one of the following: silver slurry, gold slurry, platinum slurry, silver - palladium alloy slurry; the metal slurry is a conventional commercially available product, which is composed of corresponding metal powder, epoxy resin, glass powder, and solvent; the mass fraction of the metal powder in the metal slurry is 75 - 85 wt%;

[0062] The diluent is an ethanol (or propanol) solution of butyl carbitol (or terpineol); the mass fraction of butyl carbitol (or terpineol) in the diluent is 8 - 15%;

[0063] The mass ratio of the metal slurry to the diluent is 65 - 75:25 - 35;

[0064] The optional models of the spray gun used for spraying are existing atomizing spray guns of W - 71, W - 77, W - 101, and W - 201.

[0065] The finishing method is to finish the metal layer of the conformal antenna radiation zone by laser etching to obtain a metalized fiber-reinforced ceramic-based composite material for the conformal antenna.

[0066] In the finishing process, the laser etching uses a 3D galvanometer to control the laser direction, and a picosecond laser is used for etching; the laser power is controlled to be 2-5W, the linear speed is 300-500mm / s, and the etching times are 2-4 times.

[0067] The embodiment of the present invention also provides a method for preparing the metallized fiber-reinforced ceramic-based composite material prepared by the above method.

[0068] The present invention is further described below in conjunction with some specific embodiments.

[0069] Example 1

[0070] This embodiment provides a method for preparing a metallized fiber-reinforced ceramic matrix composite material, specifically:

[0071] 1. Substrate pretreatment

[0072] The fiber-reinforced ceramic matrix composite material is processed to a predetermined size of a conformal antenna, and then its surface is polished and ground, and defects are repaired. Then, paper tape is used to shield and protect the non-working area to obtain a pretreated substrate.

[0073] Wherein, the fiber-reinforced ceramic-based composite material is a quartz fiber-reinforced quartz composite material.

[0074] The polishing and grinding is to polish the surface of the fiber-reinforced ceramic-based composite material with 1000 mesh sandpaper to remove fiber burrs caused by machining on the material surface; the defect repair is to apply a repair liquid to the defect, and then sinter at 650°C for 1 hour to repair fiber breakage, dents caused by peeling and material shortages caused by machining on the material surface.

[0075] The repair liquid is composed of silica sol, boric acid, and submicron ceramic powder; the submicron ceramic powder is silicon oxide. The mass parts of each raw material in the repair liquid are 35 parts of silica sol, 1 part of boric acid, and 55 parts of submicron ceramic powder.

[0076] 2. Preparation of composite reinforced powder

[0077] Put nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder into a ball mill, control the ball-to-material-water ratio to be 6:1:0.6, the ball milling speed to be 120 rpm. After ball milling for 30 min, take out the ball milled material and dry it to obtain a premixed powder; then put the premixed powder into an ethanol solution (volume concentration 70%) with 5 times the mass, under the stirring condition of 50 rpm, heat it up to 55 °C, keep it warm and drop in the silane coupling agent APTES; after the dropping of the silane coupling agent APTES is completed, continue to keep it warm and stir for 4 h, then filter to obtain a solid, and the solid is washed with water and dried to obtain a composite reinforced powder.

[0078] Among them, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3:5:1.

[0079] The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.2.

[0080] 3. Preparation of the interface layer

[0081] Mix the interface layer coating, solvent, and composite reinforced powder evenly to obtain an interface layer spray coating slurry; by spraying, under the condition of a spraying pressure of 0.2 MPa, use a spray gun to spray the interface layer spray coating slurry onto the surface of the pretreated substrate, and control the spraying weight gain (for every 100 cm 2 The spraying amount on the surface of the pretreated substrate is 0.4 g); after spraying, place it in an oven, dry it at 85 °C for 0.5 h, then transfer it to a muffle furnace, sinter it at 750 °C for 15 min to make the interface layer material undergo ceramic conversion, and obtain a substrate with an interface layer formed on the surface, and the thickness of its interface layer is 6.1 μm.

[0082] Among them, the interface layer coating is a polysilazane coating; the solvent is toluene.

[0083] The mass ratio of the interface layer coating, solvent, and composite reinforced powder is 84:32:12.

[0084] The spray gun model used for spraying is W-101.

[0085] 4. Preparation of the metal layer

[0086] Mix the metal slurry and the diluent evenly to obtain a metallized spray coating slurry; by spraying, under the condition of a spraying pressure of 0.2 MPa, use a spray gun to spray the metallized spray coating slurry onto the surface of the interface layer of the substrate, and control the spraying weight gain (for every 100 cm 2 The spraying amount on the surface of the pretreated substrate is 1 g); after spraying, place it in an oven, dry it at 120 °C for 0.5 h, then transfer it to a muffle furnace, sinter it at 750 °C for 10 min to obtain a substrate with a metal layer formed on the surface, and the thickness of its metal layer is 8.0 μm.

[0087] The metal slurry is a silver slurry, which is composed of silver powder, epoxy resin, glass powder and solvent, and is a conventional commercially available product; the mass fraction of the silver powder in the metal slurry is 80wt%.

[0088] The diluent is an ethanol solution of butyl carbitol; the mass fraction of butyl carbitol in the diluent is 9%.

[0089] The mass ratio of metal slurry to diluent is 70:30.

[0090] The spray gun model used for spraying is W-101.

[0091] 5. Finishing

[0092] The metal layer of the conformal antenna radiation area is finely processed by laser etching to obtain a metallized fiber-reinforced ceramic-based composite material for the conformal antenna.

[0093] Among them, laser etching uses a 3D galvanometer to control the laser direction and uses picosecond laser for etching; the laser power is controlled to 2W, the linear speed is 300mm / s, and the number of etching times is 4 times.

[0094] This embodiment also provides a method for preparing the metallized fiber-reinforced ceramic-based composite material prepared by the aforementioned method.

[0095] Example 2

[0096] This embodiment provides a method for preparing a metallized fiber-reinforced ceramic matrix composite material, specifically:

[0097] 1. Substrate pretreatment

[0098] The fiber-reinforced ceramic matrix composite material is processed to a predetermined size of a conformal antenna, and then its surface is polished and ground, and defects are repaired. Then, paper tape is used to shield and protect the non-working area to obtain a pretreated substrate.

[0099] Wherein, the fiber-reinforced ceramic matrix composite material is an alumina fiber-reinforced alumina composite material.

[0100] The polishing and grinding is to polish the surface of the fiber-reinforced ceramic-based composite material with 1000 mesh sandpaper to remove fiber burrs caused by machining on the material surface; the defect repair is to apply a repair liquid to the defect, and then sinter at 700°C for 1.5 hours to repair fiber breakage, dents caused by peeling and material shortages caused by machining on the material surface.

[0101] The repair liquid is composed of silica sol, boric acid, and submicron ceramic powder; the submicron ceramic powder is aluminum oxide. The mass percentage of each raw material in the repair liquid is 38 parts of silica sol, 3 parts of boric acid, and 61 parts of submicron ceramic powder.

[0102] 2. Preparation of composite reinforcing powder

[0103] Put nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder into a ball mill, control the ball-to-material-water ratio to be 6.2:1:0.65, the ball milling speed to be 160 rpm, after ball milling for 25 min, take out the ball milled material and dry it to obtain a premixed powder; then put the premixed powder into an ethanol solution (volume concentration 72%) with a mass 5.5 times that of the premixed powder, under the stirring condition of 60 rpm, heat up to 58 °C, keep warm and dropwise add the silane coupling agent APTES; after the dropwise addition of the silane coupling agent APTES is completed, continue to keep warm and stir for 4.5 h, then filter to obtain a solid, and the solid is washed with water and dried to obtain a composite reinforcing powder.

[0104] Among them, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3.3:5.4:1.1.

[0105] The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.23.

[0106] 3. Preparation of the interface layer

[0107] Mix the interface layer coating, solvent, and composite reinforcing powder evenly to obtain an interface layer spray coating slurry; by spraying, under the condition of a spraying pressure of 0.25 MPa, use a spray gun to spray the interface layer spray coating slurry onto the surface of the pretreated substrate, control the spraying weight gain (for every 100 cm 2 The spraying amount on the surface of the pretreated substrate is 0.5 g); after spraying, place it in an oven, dry it at 95 °C for 0.75 h, then transfer it to a muffle furnace, sinter it at 800 °C for 20 min to cause the ceramicization transformation of the interface layer material, and obtain a substrate with an interface layer formed on the surface, and the thickness of the interface layer is 7.8 μm.

[0108] Among them, the interface layer coating is a polysilazane coating; the solvent is xylene.

[0109] The mass ratio of the interface layer coating, solvent, and composite reinforcing powder is 85:34:14.

[0110] The model of the spray gun used for spraying is W-201.

[0111] 4. Preparation of the metal layer

[0112] Mix the metal slurry and the diluent evenly to obtain a metallized spray coating slurry; by spraying, under the condition of a spraying pressure of 0.25 MPa, use a spray gun to spray the metallized spray coating slurry onto the surface of the interface layer of the substrate, control the spraying weight gain (for every 100 cm 2The spraying amount on the surface of the pretreated substrate is 1.3 g); after spraying, it is placed in an oven and dried at 125 °C for 0.75 h, then transferred to a muffle furnace and sintered at 800 °C for 12 min to obtain a substrate with a metal layer formed on its surface, and the thickness of the metal layer is 12.3 μm.

[0113] Among them, the metal slurry is a silver slurry, which is composed of silver powder, epoxy resin, glass powder and solvent, and is a conventional commercially available product; the mass fraction of silver powder in the metal slurry is 80 wt%.

[0114] The diluent is an ethanol solution of butyl carbitol; the mass fraction of butyl carbitol in the diluent is 9%.

[0115] The mass ratio of the metal slurry to the diluent is 72:28.

[0116] The spray gun model used for spraying is W-201.

[0117] 5. Finishing

[0118] The metal layer in the radiation area of the conformal antenna is finely processed by laser etching to obtain a metallized fiber-reinforced ceramic matrix composite material for the conformal antenna.

[0119] Among them, the laser etching uses a 3D galvanometer to control the laser direction and etches with picosecond laser; the laser power is controlled at 4 W, the linear velocity is 450 mm / s, and the etching times are 3 times.

[0120] This embodiment also provides a preparation method of the metallized fiber-reinforced ceramic matrix composite material prepared by the foregoing method.

[0121] Example 3

[0122] This embodiment provides a preparation method of a metallized fiber-reinforced ceramic matrix composite material, specifically:

[0123] 1. Substrate pretreatment

[0124] The fiber-reinforced ceramic matrix composite material is processed to the predetermined size of the conformal antenna, and then its surface is polished, defect repaired, and the non-working area is shielded and protected with paper tape to obtain a pretreated substrate.

[0125] Among them, the fiber-reinforced ceramic matrix composite material is a mullite fiber-reinforced alumina composite material.

[0126] The polishing and grinding is to polish the surface of the fiber-reinforced ceramic matrix composite with 1000-mesh sandpaper to remove the fiber burrs on the material surface caused by machining; the defect repair is to apply the repair liquid dropwise to the defect, and then keep it at 750 °C for 2 h of heat preservation sintering to repair the dents and material shortage caused by fiber breakage and peeling on the material surface due to machining.

[0127] The repair liquid is composed of silica sol, boric acid, and submicron ceramic powder; the submicron ceramic powder is mullite. The mass dosage of each raw material in the repair liquid is 45 parts of silica sol, 5 parts of boric acid, and 65 parts of submicron ceramic powder.

[0128] 2. Preparation of composite reinforcing powder

[0129] Put nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder into a ball mill, control the ball-to-material-water ratio to be 6.5:1:0.7, the ball milling speed to be 180 rpm, after ball milling for 30 min, take out the ball milled material and dry it to obtain a premixed powder; then put the premixed powder into an ethanol solution (volume concentration 75%) with 6 times the mass, under the stirring condition of 80 rpm, heat up to 60 °C, keep warm and dropwise add the silane coupling agent APTES; after the addition of the silane coupling agent APTES is completed, continue to keep warm and stir for 5 h, then filter to obtain a solid, and the solid is washed with water and dried to obtain a composite reinforcing powder.

[0130] Among them, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3.5:6:1.2.

[0131] The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.25.

[0132] 3. Preparation of the interface layer

[0133] Mix the interface layer coating, solvent, and composite reinforcing powder evenly to obtain an interface layer spray coating slurry; by spraying, under the spraying pressure of 0.3 MPa, use a spray gun to spray the interface layer spray coating slurry onto the surface of the pretreated substrate, and control the spraying weight gain (for every 100 cm 2 The spraying amount on the surface of the pretreated substrate is 0.6 g); after spraying, place it in an oven, dry it at 100 °C for 1 h, then transfer it to a muffle furnace, sinter it at 850 °C for 30 min to make the interface layer material undergo ceramic conversion to obtain a substrate with an interface layer formed on its surface, and the thickness of the interface layer is 10 μm.

[0134] Among them, the interface layer coating is a polysilazane coating; the solvent is toluene.

[0135] The mass ratio of the interface layer coating, solvent, and composite reinforcing powder is 88:40:16.

[0136] The spray gun model used for spraying is W-201.

[0137] 4. Preparation of metal layer

[0138] The metal slurry and the diluent are mixed evenly to obtain a metallized spray slurry; the metallized spray slurry is sprayed onto the interface layer surface of the substrate by a spray gun under a spray pressure of 0.3 MPa, and the spray weight gain (per 100 cm 2 The spraying amount on the surface of the pretreated substrate is 1.5 g); after spraying, it is placed in an oven, dried at 150° C. for 1 hour, transferred to a muffle furnace, and sintered at 850° C. for 15 minutes to obtain a substrate with a metal layer formed on the surface, and the thickness of the metal layer is 14.8 μm.

[0139] Among them, the metal slurry is platinum slurry, which is composed of platinum powder, epoxy resin, glass powder and solvent, and is a conventional commercially available product; the mass fraction of platinum powder in the metal slurry is 80wt%.

[0140] The diluent is an ethanol solution of butyl carbitol; the mass fraction of butyl carbitol in the diluent is 9%.

[0141] The mass ratio of metal slurry to diluent is 75:25.

[0142] The spray gun model used for spraying is W-201.

[0143] 5. Finishing

[0144] The metal layer of the conformal antenna radiation area is finely processed by laser etching to obtain a metallized fiber-reinforced ceramic-based composite material for the conformal antenna.

[0145] Among them, laser etching uses a 3D galvanometer to control the laser direction and uses picosecond laser for etching; the laser power is controlled to 5W, the linear speed is 500mm / s, and the number of etching times is 2 times.

[0146] This embodiment also provides a method for preparing the metallized fiber-reinforced ceramic-based composite material prepared by the aforementioned method.

[0147] Comparative Example 1

[0148] For the sake of comparison, the method for preparing the metallized fiber-reinforced ceramic matrix composite material of Comparative Example 1 adopts the technical solution of Example 3, except that the step of preparing the composite reinforcing powder is omitted, and the addition of the composite reinforcing powder to the interface layer spray slurry is omitted.

[0149] The coating-related properties of the metallized fiber-reinforced ceramic matrix composites of Examples 1-3 and Comparative Example 1 were respectively detected. Specifically, the bonding performance between the coating and the substrate at room temperature was detected (specific reference: GB / T9286-2021); and for the metallized fiber-reinforced ceramic matrix composites of Examples 1-2 after quartz lamp thermal assessment at 850 °C / 600 s, the bonding performance between the coating and the substrate was detected (specific reference: GB / T9286-2021); for the metallized fiber-reinforced ceramic matrix composites of Example 3 and Comparative Example 1 after quartz lamp thermal assessment at 1000 °C / 600 s, the bonding performance between the coating and the substrate was detected (specific reference: GB / T9286-2021).

[0150] Meanwhile, during the preparation of the metallized fiber-reinforced ceramic matrix composites of Examples 1-3 and Comparative Example 1, the dielectric loss tangent values of the pretreated substrate and the substrate with an interfacial layer formed on its surface (and the interfacial layer was removed by laser) were respectively detected, and the difference in the dielectric loss tangent values of the two was calculated (i.e., the growth rate of the loss tangent value) to evaluate the influence of the pretreatment and interfacial layer processes of the present invention on the wave transmission performance of the pretreated substrate. The calculation method for the growth rate of the dielectric loss tangent value of the substrate with an interfacial layer formed on its surface (and the interfacial layer was removed by laser) compared to the pretreated substrate is [(dielectric loss tangent value of the substrate with an interfacial layer formed on its surface (and the interfacial layer was removed by laser) - dielectric loss tangent value of the pretreated substrate) / dielectric loss tangent value of the pretreated substrate] × 100%. The specific results are as follows:

[0151]

[0152] Furthermore, the metallized fiber-reinforced ceramic matrix composites of Examples 1-3 and Comparative Example 1 were respectively placed in a quartz lamp array, and in an air gas environment, thermal shock cycle tests at 850 °C (Examples 1-2) and 1000 °C (Example 3 and Comparative Example 1) were respectively carried out. Specifically, the metallized fiber-reinforced ceramic matrix composites of Examples 1-2 in the quartz lamp array were heated to 850 °C at a heating rate of 20 °C / s, held for 10 min, and then quenched in water to room temperature; the metallized fiber-reinforced ceramic matrix composites of Example 3 and Comparative Example 1 in the quartz lamp array were heated to 1000 °C at a heating rate of 20 °C / s, held for 10 min, and then quenched in water to room temperature; after repeating the heating and quenching processes of rapid heating and quenching in water 10 times respectively, it was observed whether the coatings of each composite material cracked or deformed, and the bonding performance between the coating and the substrate was detected (specific reference: GB / T9286-2021). The specific results are shown in the following table:

[0153]

[0154] It can be seen that in the preparation of the metallized fiber-reinforced ceramic matrix composite of the present invention, the fiber-reinforced ceramic matrix composite is processed to the predetermined size of the conformal antenna cover (window) as required. After obtaining the pretreated substrate, nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder are mixed evenly and treated with the silane coupling agent APTES to obtain a composite reinforcing powder. Through the modification treatment of the premixed powder by the silane coupling agent APTES, while improving its dispersibility in the interface layer spray coating slurry, its bonding property with the interface layer coating is improved. Then, the composite reinforcing powder is mixed with the interface layer coating (polysilazane coating or polysiloxane coating) to obtain an interface layer spray coating slurry, which is then sprayed onto the surface of the pretreated substrate to form an interface layer; and the shrinkage is inhibited by the addition of the composite reinforcing powder, the internal stress is reduced, the thermal stability, thermal shock resistance, and mechanical properties of the interface layer are improved; and the bonding property between the interface layer and the matrix is improved, and mechanical interlocking is formed through the anchoring effect of the composite reinforcing powder on the surface of the pretreated substrate to inhibit interface peeling; at the same time, through the setting of the interface layer, the wettability problem between the metal layer and the composite material is effectively improved, and the bonding property between the coating and the substrate is optimized. Then, the metallized spray coating slurry is coated on the interface layer coating area to form a metal layer, and finally, after precision machining, the metallized fiber-reinforced ceramic matrix composite is obtained; the foregoing technical means cooperate with each other and work synergistically, which can effectively overcome the problems that the existing metallization methods are not applicable to the preparation of conformal antennas for fiber-reinforced ceramic matrix composites, and overcome the problems of complex metallization process and strong equipment dependence, improve the bonding property between the metallized layer and the fiber-reinforced ceramic matrix composite, and improve the coating stability.

[0155] Unless otherwise specified, the percentages used in the present invention are all mass percentages.

[0156] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a metallized fiber-reinforced ceramic matrix composite, characterized in that, It includes the following steps: substrate pretreatment, preparation of composite reinforcing powder, preparation of interface layer, preparation of metal layer, and finishing machining; For the substrate pretreatment, the fiber-reinforced ceramic matrix composite is processed to the size of the conformal antenna, and after surface polishing and defect repair, a pretreated substrate is obtained; For the preparation of the composite reinforcing powder, nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder are mixed evenly to obtain a premixed powder; After the premixed powder is treated with the silane coupling agent APTES, a composite reinforcing powder is obtained; For the preparation of the interface layer, the interface layer coating, solvent, and composite reinforcing powder are mixed evenly to obtain an interface layer spray coating slurry; after the interface layer spray coating slurry is sprayed onto the surface of the pretreated substrate, it is dried and sintered to obtain a substrate with an interface layer formed on its surface; The interface layer coating is a polysilazane coating or a polysiloxane coating; For the preparation of the metal layer, after the metallization spray coating slurry is sprayed onto the surface of the interface layer of the substrate, it is dried and sintered to obtain a substrate with a metal layer formed on its surface.

2. The preparation method of the metallized fiber-reinforced ceramic matrix composite material according to claim 1, characterized in that, In the substrate pretreatment, defect repair is carried out by spot coating the defect with a repair liquid and then sintering; The repair liquid is composed of the following raw materials in parts by weight: 35-45 parts of silica sol, 1-5 parts of boric acid, and 55-65 parts of submicron ceramic powder; The submicron ceramic powder is selected from: silicon oxide, alumina, and mullite.

3. The method for preparing a metallized fiber-reinforced ceramic matrix composite according to claim 1, wherein, In the preparation of the composite reinforcing powder, the premixed powder is put into an ethanol solution, stirred and heated to 55-60 °C, kept warm and the silane coupling agent APTES is dropped in; after the dropping of the silane coupling agent APTES is completed, continue to keep warm and stir for 4-5 h, then the solid is separated, and the solid is washed with water and dried to obtain the composite reinforcing powder.

4. The preparation method of the metallized fiber-reinforced ceramic matrix composite according to claim 1, characterized in that, In the preparation of the composite reinforcing powder, the mass ratio of nano boron nitride powder, nano hafnium nitride powder, and nano tantalum diboride powder is 3-3.5:5-6:1-1.2; The mass ratio of the premixed powder to the silane coupling agent APTES is 1:0.2-0.

25.

5. The method for preparing a metallized fiber-reinforced ceramic matrix composite according to claim 1, characterized in that, In the preparation of the interface layer, the mass ratio of the interface layer coating, solvent, and composite reinforcing powder is 84-88:32-40:12-16; The spraying pressure of the coating slurry for the interface layer is 0.2 - 0.3 MPa, and the spraying weight gain is controlled to be per 100 cm 2 The spraying weight on the surface of the pretreated substrate is 0.4 - 0.6 g.

6. The preparation method of the metallized fiber-reinforced ceramic matrix composite according to claim 1, characterized in that, In the preparation of the interface layer, the drying temperature is 85-100 °C and the drying time is 0.5-1 h; The sintering temperature is 750-850 °C and the sintering time is 15-30 min; The thickness of the interface layer is 6-10 μm.

7. The method for preparing a metallized fiber-reinforced ceramic matrix composite according to claim 1, characterized in that, In the preparation of the metal layer, the metallization spray coating slurry contains a metal slurry and a diluent; The metal slurry is one of the following: silver slurry, gold slurry, platinum slurry, silver-palladium alloy slurry; The diluent is an ethanol or propanol solution of butyl carbitol or terpineol; The mass ratio of the metal slurry to the diluent is 65-75:25-35.

8. The method for preparing a metallized fiber-reinforced ceramic matrix composite according to claim 1, characterized in that, In the preparation of the metal layer, the spraying pressure of the metallized spraying coating slurry is 0.2 - 0.3 MPa, and the spraying weight gain is controlled to be 2 the spraying weight on the surface of the interface layer is 1 - 1.5 g; The drying temperature is 120-150 °C and the drying time is 0.5-1 h; The sintering temperature is 750-850 °C and the sintering time is 10-15 min; The thickness of the metal layer is 8-15 μm.

9. The method for preparing a metallized fiber-reinforced ceramic matrix composite according to claim 1, wherein For the finishing machining, laser etching is used to finish machine the metal layer in the radiation area of the conformal antenna to obtain a metallized fiber-reinforced ceramic matrix composite for the conformal antenna; The laser etching uses a 3D galvanometer to control the laser direction and carries out etching with picosecond laser; The laser power of the laser etching is 2 - 5 W, the linear velocity is 300 - 500 mm / s, and the number of etching times is 2 - 4 times.

10. A metallized fiber-reinforced ceramic matrix composite material, characterized in that, It is prepared by using the preparation method described in any one of claims 1 - 9.

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