A three-dimensional lattice structure high temperature wave absorbing material and preparation method thereof

Abstract

The present invention relates to the technical field of high-temperature absorbing materials, and specifically discloses a three-dimensional lattice structure high-temperature absorbing material, wherein the absorbing material comprises, from bottom to top, a continuous fiber reinforced ceramic matrix composite lower panel, a three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, and a high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite panel. The three-dimensional lattice structure high-temperature absorbing material of the present invention has excellent broadband absorbing performance, and the absorbing frequency band covers 1 to 18 GHz; it has low density, excellent thermal insulation performance, good temperature resistance, and high high-temperature stability.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature absorbing materials, and in particular relates to a high-temperature absorbing material with a three-dimensional lattice structure and a preparation method thereof. Background Art

[0002] Three-dimensional lattice material is a new type of lightweight, high-strength and multifunctional material with the characteristics of low density, high strength, good thermal insulation and strong impact resistance. It has broad application prospects in the aerospace field. Three-dimensional lattice absorbing materials not only have the general characteristics of three-dimensional lattice structures, but also can significantly attenuate radar wave energy and achieve absorbing performance through the optimization design of structural and material electromagnetic parameters. At present, the main types of three-dimensional lattice absorbing materials are honeycomb absorbing composite materials. Honeycomb absorbing composite materials have the characteristics of low density, strong absorption, wide absorption bandwidth and strong designability of absorbing performance. At the same time, they have good mechanical properties and can be used as structural parts to achieve structural absorbing integration. It has become an important research and development direction of current stealth materials.

[0003] Chinese Patent No. ZL201610166422.5 discloses a method for preparing a honeycomb radar absorbing material, including immersing a honeycomb core in a slurry containing functionalized graphene, resin and other components, curing the honeycomb core to obtain first to third absorbing honeycombs, bonding the first to third absorbing honeycombs together in sequence to obtain a honeycomb structure, and then covering the upper and lower surfaces of the cured honeycomb structure with a PMI skin layer respectively, and bonding a metal base reflective layer under the PMI skin layer on the lower surface to obtain a honeycomb radar absorbing material, which has a broadband stealth performance; Chinese Patent No. ZL201911071094.0 discloses a method for preparing a foam honeycomb composite sandwich absorbing material, including using a flat hot press to press an aramid honeycomb into a hard absorbing foam of the same thickness to obtain an absorbing foam honeycomb core material, and then pasting a transparent skin on the upper and lower surfaces of the absorbing foam honeycomb core to obtain a foam honeycomb composite sandwich absorbing material, which has a broadband strong absorption effect. It can be found that the existing honeycomb absorbing composite materials are mainly made by spraying or impregnating a certain absorbing resin-based slurry on the honeycomb wall, or by filling absorbing foam, and finally covering the upper and lower surfaces of the honeycomb core with skins. The honeycomb absorbing composite materials contain a large amount of resin or foam and other materials with poor temperature resistance. They are all organic material systems and do not have high temperature resistance. Summary of the invention

[0004] The purpose of the present invention is to provide a three-dimensional lattice structure high-temperature absorbing material and a preparation method thereof. The three-dimensional lattice structure high-temperature absorbing material has excellent broadband absorbing properties and temperature resistance, and overcomes the defects of the prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides a three-dimensional lattice structure high-temperature absorbing material, which comprises, from bottom to top (the top is the incident direction of the electromagnetic wave), a continuous fiber reinforced ceramic matrix composite lower panel, a three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, and a high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite panel. The continuous fiber reinforced ceramic matrix composite lower panel is a continuous carbon fiber reinforced ceramic matrix composite or a low-resistance continuous silicon carbide fiber reinforced ceramic matrix composite.

[0006] Preferably, in the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the silicon carbide fibers in the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material lattice structure are in the form of a two-dimensional fabric, and the thickness direction of the two-dimensional fabric is parallel to the upper and lower panels, and the cross-section of the three-dimensional lattice structure in the direction parallel to the thickness of the two-dimensional fabric is a square, the side length of the square is 4~20mm, the thickness of the silicon carbide fiber two-dimensional fabric is 0.2~0.5mm, and the resistivity of the silicon carbide fiber is 1~20Ω·cm.

[0007] Preferably, in the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the reinforcement of the lower panel of the continuous fiber reinforced ceramic matrix composite material is two-dimensional cloth, needle punching, stitching, 2.5D, or 3D fiber fabric.

[0008] Preferably, in the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the resistivity of the silicon carbide fiber in the low-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material is less than 0.1Ω·cm.

[0009] Preferably, in the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the reinforcement of the upper panel of the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material is a two-dimensional cloth, acupuncture, stitching, 2.5D, 3D silicon carbide fiber fabric, and the resistivity of the silicon carbide fiber is greater than 1×10 4 Ω·cm.

[0010] Preferably, in the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the matrix in the continuous carbon fiber reinforced ceramic matrix composite lower panel, the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, and the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite upper panel is the same, and the matrix is ​​silicon carbide, silicon oxygen carbon, silicon carbon nitrogen, silicon boron nitrogen, boron nitride or silicon boron carbon nitrogen.

[0011] A method for preparing the above-mentioned three-dimensional lattice structure high-temperature absorbing material comprises the following steps:

[0012] (1) According to the designed lattice structure height, the silicon carbide fiber two-dimensional fabric with a lattice structure that meets the design requirements is cut into fabric strips, the width of the fabric strip is the height of the lattice, and the length of the fabric strip is the width of the absorbing material; according to the side length of the square section of the three-dimensional lattice structure, a polypropylene low carbon residue adhesive strip is bonded to the position to be cut to prevent the fabric from unraveling during cutting; the incision is made in the width direction of the fabric, the length of the incision is 0.5~0.6 times the width of the fabric strip, and the incision distance is the side length of the square section;

[0013] (2) Dividing the absorbing material into two directions, X and Y, along the plane, arranging the fabric strips obtained in step (1) along the X and Y directions respectively, with the cuts of the fabric strips in the X direction being arranged opposite to the cuts of the fabric strips in the Y direction, and the cuts in the X and Y directions being embedded one by one to assemble into a lattice structure fabric;

[0014] (3) Laying out the lower panel fiber fabric, the lattice structure fabric, and the upper panel fiber fabric, using carbon fiber or silicon carbide fiber yarn to sew near the interlacing points of the fabric strips in the X and Y directions of the lattice structure fabric, so that the three layers of fabric form an integral fiber woven piece;

[0015] (4) using silicon carbide, silicon oxygen carbon, silicon carbon nitrogen, silicon boron nitrogen, boron nitride or silicon boron carbon nitrogen organic precursor solution as an impregnation solution, and using a precursor impregnation and cracking process to impregnate, high-temperature crack and perform 2 to 4 initial densification on the integral fiber woven part obtained in step (3);

[0016] (5) After the initial densification is completed, drainage holes with a diameter of 2-3 mm and a hole spacing of 5-20 mm are drilled on the lower panel to facilitate the effective entry and exit of the precursor solution in the subsequent densification process;

[0017] (6) Continue the densification process for 6 to 8 times to complete the preparation of the three-dimensional lattice structure high-temperature absorbing material.

[0018] Preferably, in the preparation method of the above-mentioned three-dimensional lattice structure high-temperature absorbing material, the mass content of the precursor in the precursor impregnation solution is not less than 40%; the impregnation and cracking process parameters are: vacuum impregnation time is not less than 4 hours, and the pressure is not greater than -0.09MPa; the high-temperature cracking temperature is 800~1000℃, and the time is 0.5~1h.

[0019] Preferably, in the method for preparing the above three-dimensional lattice structure high-temperature absorbing material, the thickness of the polypropylene low carbon residue strip is 0.02-0.03 mm.

[0020] Compared with the existing technology, the present invention has the following beneficial effects:

[0021] 1. The three-dimensional lattice structure high-temperature absorbing material of the present invention has the characteristics of high temperature resistance and excellent broadband absorbing performance. The temperature resistance can reach above 1000°C, and the absorbing frequency band covers 1~18GHz.

[0022] 2. The three-dimensional lattice structure high-temperature absorbing material of the present invention can significantly attenuate radar wave energy in a wide frequency band and achieve absorbing performance by optimizing the structural parameters of the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material lattice structure and the electrical properties of silicon carbide fibers.

[0023] 3. The three-dimensional lattice structure high-temperature absorbing material of the present invention is composed of high-temperature resistant materials, has low density, high strength, and has excellent properties such as good temperature resistance, high high-temperature stability, and heat insulation.

[0024] 4. The three-dimensional lattice structure high-temperature absorbing material of the present invention adopts an integrated composite material molding process, and the high-temperature absorbing material is molded in one step, with simple process and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the three-dimensional lattice structure high-temperature absorbing material in Example 1 of the present invention.

[0026] Figure 2 This is a schematic diagram of the three-dimensional lattice structure fabric structure in Example 1 of the present invention.

[0027] Figure 3 This is a reflectivity curve diagram of the high-temperature absorbing material with a three-dimensional lattice structure in Example 1 of the present invention.

[0028] Figure 4 This is a reflectivity curve diagram of the high-temperature absorbing material with a three-dimensional lattice structure in Example 2 of the present invention.

[0029] Description of main reference numerals:

[0030] 1-Continuous carbon fiber reinforced ceramic matrix composite lower panel, 2-Three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, 3-High resistance continuous silicon carbide fiber reinforced ceramic matrix composite upper panel. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0032] Example 1

[0033] A three-dimensional lattice structure high temperature absorbing material such as Figure 1As shown, the upper part is the incident direction of the electromagnetic wave. The absorbing material is composed of a lower panel 1 of a continuous carbon fiber reinforced ceramic matrix composite material, a lattice structure 2 of a three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material, and an upper panel 3 of a high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material from bottom to top. The three layers are formed into an integral fabric through a fiber weaving process and formed through an integrated composite material process. The ceramic matrix is ​​silicon oxygen carbon. The reinforcement of the continuous carbon fiber reinforced ceramic matrix composite material is a 2.5D carbon fiber fabric with a thickness of 1 mm. In the lattice structure of the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material, the silicon carbide fiber is in the form of a two-dimensional fabric, and the thickness direction of the two-dimensional fabric is parallel to the upper and lower panels. The cross-section of the three-dimensional lattice structure parallel to the thickness is a square with a side length of 5 mm. The thickness of the two-dimensional silicon carbide fiber fabric is 0.25 mm, and the resistivity of the silicon carbide fiber is 7.5 Ω·cm. The reinforcement of the upper panel of the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material is a two-dimensional silicon carbide fiber fabric with a thickness of 0.6 mm. The resistivity of the silicon carbide fiber is 5×10 5 Ω·cm.

[0034] This embodiment also provides a method for preparing a three-dimensional lattice structure high-temperature absorbing material, comprising the following steps:

[0035] (1) Prepare carbon fiber fabric for the lower panel and silicon carbide fiber fabric for the upper panel respectively to meet the design requirements;

[0036] (2) Prepare a two-dimensional silicon carbide fiber fabric with a lattice structure that meets the design requirements. According to the designed lattice structure height (50 mm), use a paper cutter to cut the silicon carbide fiber two-dimensional fabric into fabric strips. The width of the fabric strip is the height of the lattice, and the length of the fabric strip is the width of the absorbing material. According to the side length of the square section of the three-dimensional lattice structure, glue a polypropylene low carbon residue adhesive strip at the position to be cut to prevent the fabric from unraveling during cutting. Cut in the width direction of the fabric. The length of the cut is 0.5 times the width of the fabric strip, and the cut distance is the side length of the square section.

[0037] (3) The absorbing material is divided into two directions, X and Y, in the plane. The fabric strips obtained in step (2) are arranged in the X and Y directions respectively, with the cut in the X direction facing upward and the cut in the Y direction facing downward. The cuts in the X and Y directions are embedded one by one to assemble into a lattice structure fabric as shown in FIG. Figure 2 As shown;

[0038] (4) Laying out the carbon fiber fabric of the lower panel, the lattice structure fabric, and the silicon carbide fiber fabric of the upper panel, and sewing them near the interlacing points of the fabric strips in the X and Y directions with silicon carbide fiber yarns, so that the three layers of fabric form a whole;

[0039] (5) Using a silicone alcohol solution as an impregnation solution, the precursor mass content in the impregnation solution is 60%, and the fiber woven part obtained in step (4) is impregnated, pyrolyzed at high temperature, and initially densified three times using a precursor impregnation pyrolysis process. The impregnation pyrolysis process parameters are: vacuum impregnation time is 4 hours, pressure is -0.09 MPa; high temperature pyrolysis temperature is 850°C, and time is 1 hour;

[0040] (6) After the initial densification is completed, drainage holes with a diameter of 2 mm and a hole spacing of 10 mm are drilled on the lower panel to facilitate the effective entry and exit of the precursor solution in the subsequent densification process;

[0041] (7) The densification process is continued for 8 times to complete the preparation of the three-dimensional lattice structure high-temperature absorbing material.

[0042] The reflectivity curve of the three-dimensional lattice structure high-temperature absorbing material prepared in this embodiment at 1000°C is as follows: Figure 3 As shown, the reflectivity of the absorbing material is basically below -15dB in the range of 1 to 18 GHz, and it has excellent absorbing performance.

[0043] Example 2

[0044] A three-dimensional lattice structure high-temperature absorbing material, the upper part is the incident direction of electromagnetic waves, and the absorbing material is composed of a continuous silicon carbide fiber reinforced ceramic matrix composite lower panel (silicon carbide fiber resistivity is 0.05Ω·cm), a three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, and a high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite upper panel from bottom to top. The three layers are formed into an integral fabric through a fiber braiding process and formed through an integrated composite material process. The ceramic matrix is ​​silicon carbide. The reinforcement of the continuous carbon fiber reinforced ceramic matrix composite is a stitched carbon fiber fabric with a thickness of 2mm. In the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, the silicon carbide fiber is in the form of a two-dimensional fabric, and the thickness direction of the two-dimensional fabric is parallel to the upper and lower panels. The cross-section of the three-dimensional lattice structure in the direction parallel to the thickness is a square with a side length of 15mm. The thickness of the silicon carbide fiber two-dimensional fabric is 0.3mm, and the resistivity of the silicon carbide fiber is 1.8Ω·cm. The reinforcement of the upper panel of the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material is a two-dimensional fabric of silicon carbide fiber with a thickness of 0.4 mm. The resistivity of the silicon carbide fiber is 4×10 4 Ω·cm.

[0045] This embodiment also provides a method for preparing a three-dimensional lattice structure high-temperature absorbing material, comprising the following steps:

[0046] (1) Preparing silicon carbide fiber fabrics for the lower panel and upper panel respectively that meet the design requirements;

[0047] (2) Prepare a two-dimensional silicon carbide fiber fabric with a lattice structure that meets the design requirements. According to the designed lattice structure height (15 mm), use a laser to cut the silicon carbide fiber two-dimensional fabric into fabric strips. The width of the fabric strip is the height of the lattice, and the length of the fabric strip is the width of the absorbing material. According to the side length of the square section of the three-dimensional lattice structure, glue a polypropylene low carbon residue adhesive strip at the position to be cut to prevent the fabric from unraveling during cutting. Cut in the width direction of the fabric. The length of the cut is 0.6 times the width of the fabric strip, and the cut distance is the side length of the square section.

[0048] (3) Divide the absorbing material into two directions, X and Y, along the plane, and arrange the fabric strips obtained in step (2) along the X and Y directions, respectively, with the cut in the X direction facing upward and the cut in the Y direction facing downward, and the cuts in the X and Y directions are embedded one by one to assemble into a lattice structure fabric;

[0049] (4) Laying out the silicon carbide fiber fabric of the lower panel, the lattice structure fabric, and the silicon carbide fiber fabric of the upper panel, and sewing them near the interlacing points of the fabric strips in the X and Y directions respectively using silicon carbide fiber yarns, so that the three layers of fabric form a whole;

[0050] (5) Using a xylene solution of polycarbosilane, an organic precursor of silicon carbide, as an impregnation solution, the mass content of the precursor in the impregnation solution is 50%, and the fiber woven part obtained in step (4) is impregnated, pyrolyzed at high temperature, and initially densified three times using a precursor impregnation pyrolysis process. The impregnation pyrolysis process parameters are: vacuum impregnation time is 4 hours, pressure is -0.09 MPa; high temperature pyrolysis temperature is 900 ° C, and time is 0.5 hours;

[0051] (6) After the initial densification is completed, drainage holes with a diameter of 3 mm and a hole spacing of 10 mm are drilled on the lower plate to facilitate the effective entry and exit of the precursor solution in the subsequent densification process;

[0052] (7) The densification process is continued for 8 times to complete the preparation of the three-dimensional lattice structure high-temperature absorbing material.

[0053] The reflectivity curve of the three-dimensional lattice structure high temperature absorbing material prepared in this embodiment at 1000°C is as follows: Figure 4 As shown, the absorbing frequency band can cover 1~18GHz, and the reflectivity of 4~18GHz is basically below -10dB, which has excellent absorbing performance.

[0054] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A three-dimensional lattice structure high temperature absorbing material, characterized in that: The absorbing material comprises, from bottom to top, a continuous fiber reinforced ceramic matrix composite lower panel, a three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite lattice structure, and a high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite panel. The continuous fiber reinforced ceramic matrix composite lower panel is a continuous carbon fiber reinforced ceramic matrix composite or a low-resistance continuous silicon carbide fiber reinforced ceramic matrix composite. The silicon carbide fibers in the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material lattice structure are in the form of two-dimensional fabrics, and the thickness direction of the two-dimensional fabric is parallel to the upper and lower panels. The cross-section of the lattice structure in the direction parallel to the thickness of the two-dimensional fabric is a square, the side length of the square is 4 to 20 mm, the thickness of the silicon carbide fiber two-dimensional fabric is 0.2 to 0.5 mm, and the resistivity of the silicon carbide fiber is 1 to 20 Ω·cm; the matrix in the lower panel of the continuous fiber reinforced ceramic matrix composite material, the three-dimensional lossy continuous silicon carbide fiber reinforced ceramic matrix composite material lattice structure, and the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material upper panel is the same, and the matrix is ​​silicon carbide, silicon oxygen carbon, silicon carbon nitrogen, silicon boron nitrogen, boron nitride or silicon boron carbon nitrogen.

2. The three-dimensional lattice structure high temperature absorbing material according to claim 1, characterized in that: The reinforcement of the lower panel of the continuous fiber reinforced ceramic matrix composite material is a two-dimensional cloth, acupuncture, stitching, 2.5D, or 3D fiber fabric.

3. The three-dimensional lattice structure high temperature absorbing material according to claim 1, characterized in that: The resistivity of the silicon carbide fiber in the low-resistance continuous silicon carbide fiber reinforced ceramic matrix composite material is less than 0.1Ω·cm.

4. The three-dimensional lattice structure high temperature absorbing material according to claim 1, characterized in that: The reinforcement of the high-resistance continuous silicon carbide fiber reinforced ceramic matrix composite upper panel is a two-dimensional cloth, needle punching, stitching, 2.5D, 3D silicon carbide fiber fabric, and the resistivity of the silicon carbide fiber is greater than 1×10 4 Ω·cm.

5. A method for preparing the three-dimensional lattice structure high temperature absorbing material according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) According to the designed lattice structure height, the silicon carbide fiber two-dimensional fabric with a lattice structure that meets the design requirements is cut into fabric strips, the width of the fabric strip is the height of the lattice, and the length of the fabric strip is the width of the absorbing material; According to the side length of the square section of the three-dimensional lattice structure, a polypropylene low carbon residue adhesive strip is bonded at the position to be cut to prevent the fabric from unraveling during cutting; the cut is made in the width direction of the fabric, the length of the cut is 0.5-0.6 times the width of the fabric strip, and the cut distance is the side length of the square section; (2) Dividing the absorbing material into two directions, X and Y, along the plane, arranging the fabric strips obtained in step (1) along the X and Y directions respectively, with the cuts of the fabric strips in the X direction being arranged opposite to the cuts of the fabric strips in the Y direction, and the cuts in the X and Y directions being embedded one by one to assemble into a lattice structure fabric; (3) Laying out the lower panel fiber fabric, the lattice structure fabric, and the upper panel fiber fabric, using carbon fiber or silicon carbide fiber yarn to sew near the interlacing points of the fabric strips in the X and Y directions of the lattice structure fabric, so that the three layers of fabric form an integral fiber woven piece; (4) using silicon carbide, silicon oxygen carbon, silicon carbon nitrogen, silicon boron nitrogen, boron nitride or silicon boron carbon nitrogen organic precursor solution as an impregnation solution, and using a precursor impregnation and cracking process to impregnate, high-temperature crack and perform 2 to 4 initial densification on the fiber woven part obtained in step (3); (5) After the initial densification is completed, drainage holes with a diameter of 2-3 mm and a hole spacing of 5-20 mm are drilled on the lower panel to facilitate the effective entry and exit of the precursor solution in the subsequent densification process; (6) Continue the densification process for 6 to 8 times to complete the preparation of the three-dimensional lattice structure high-temperature absorbing material.

6. The method for preparing a three-dimensional lattice structure high temperature absorbing material according to claim 5, characterized in that: The precursor mass content in the precursor impregnation solution is not less than 40%; the impregnation cracking process parameters are: vacuum impregnation time is not less than 4h, and the pressure is not greater than -0.09MPa; The high temperature cracking temperature is 800~1000℃ and the time is 0.5~1h.

7. The method for preparing a three-dimensional lattice structure high temperature absorbing material according to claim 5, characterized in that: The polypropylene low carbon residue rubber strip has a thickness of 0.02-0.03 mm.

Images