Al2o3 fiber reinforced zrc wave-absorbing composite material and preparation method thereof

Abstract

The application discloses an Al2O3 fiber reinforced ZrC wave-absorbing composite material and a preparation method thereof, and comprises the following steps: taking an Al2O3 chopped fiber plate as a frame, and compounding the Al2O3 chopped fiber plate with PDC-ZrC ceramics to obtain the Al2O3 fiber reinforced ZrC wave-absorbing composite material. The material can improve the impedance matching performance between ZrC ceramics and free space, and has excellent wave-absorbing performance.

Description

Technical Field

[0001] This invention belongs to the field of microwave absorbing materials technology, and relates to an Al2O3 fiber reinforced ZrC microwave absorbing composite material and its preparation method. Background Technology

[0002] With the rapid development of advanced radar detection and precision guidance technologies, the research and development of high-performance stealth materials has become an important feature of advanced weaponry. Polymer-converted zirconium carbide ceramics (PDC-ZrC) exhibits high temperature resistance and excellent conductivity, making it a promising radar-absorbing material. However, when PDC-ZrC is used alone as a radar-absorbing material, its excessively high conductivity leads to poor impedance matching with free space, causing electromagnetic wave reflection and significantly reducing its absorption capacity. Therefore, improving the impedance matching of PDC-ZrC and enhancing its radar-absorbing performance is urgently needed.

[0003] Reference 1, “Liu Dan, Qiu Wenfeng, Cai Tao, et al. Preparation and ceramization of zirconium carbide liquid-phase ceramic precursors [J]. Aerospace Materials and Processes, 2014, 44(01):79-83,” reports the ceramization process of polymer-converted zirconium carbide ceramics at different pyrolysis temperatures (1000-1600℃). The study found that with increasing temperature, the zirconium carbide liquid-phase ceramic precursor gradually transforms from ZrO2 to ZrC. Furthermore, at pyrolysis at 1600℃, all ZrO2 in the system is converted to ZrC.

[0004] Reference 2, "Zeli Jia, Xiaomeng Fan, Jiangyi He, et al. Evolution of microstructure and electromagnetic interference shielding performance during the ZrC precursor thermal decomposition process. International Journal of Minerals, Metallurgy and Materials, 2023, 30: 1398-1406," reports the electromagnetic shielding performance of polymer-converted zirconium carbide ceramics at different pyrolysis temperatures (900-1700℃). The study found that pure PDC-ZrC exhibits excellent electromagnetic shielding performance, causing a large amount of electromagnetic waves to be reflected from the material surface without being absorbed by the material, resulting in poor impedance matching. Therefore, how to improve this problem is worth considering and solving. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an Al2O3 fiber reinforced ZrC microwave absorbing composite material and its preparation method. This material can improve the impedance matching performance between ZrC ceramic and free space and has excellent microwave absorption performance.

[0006] To achieve the above objectives, the preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a frame, the Al2O3 chopped fiberboard is composited with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material.

[0007] Furthermore, the density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.4-0.6 g / cm³. 3 .

[0008] Furthermore, the density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 2.1-2.5 g / cm³. 3 .

[0009] Furthermore, the specific steps include:

[0010] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0011] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0012] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0013] 4) The pre-sintered sample is subjected to heat treatment;

[0014] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0015] Furthermore, in step 1), the Al2O3 chopped fiberboard is cut into the shape required for the microwave absorption test using a utility knife and a file.

[0016] Furthermore, the soaking time in step 2) is 1-2 hours;

[0017] The drying temperature in step 2) is 150℃-200℃, and the drying time is 2-3 hours.

[0018] Furthermore, in step 3), N1 is 2, 3, or 4.

[0019] Furthermore, the operation process in step 4) is as follows:

[0020] The pre-sintered sample is placed in a heat treatment furnace, and then the furnace temperature is raised from room temperature to 1000-1200℃ at a heating rate of 3-10℃ / min in a flowing Ar atmosphere, and then raised to 1500-1600℃ at a heating rate of 3-10℃ / min. The temperature is then held for 1-4 hours and then naturally cooled to room temperature.

[0021] Furthermore, N2 is 2.

[0022] The Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention is prepared based on the preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material.

[0023] The present invention has the following beneficial effects:

[0024] In the specific operation of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material and its preparation method described in this invention, Al2O3 chopped fiberboard is cut into microwave absorption performance test pieces, and ZrC liquid phase precursor solution is impregnated under vacuum conditions. Then, through multiple impregnation-drying-sintering processes, Al2O3 chopped fiber-ZrC microwave absorbing composite material is obtained. Al2O3 chopped fiber has good wave transmission properties, which can improve the impedance mismatch of PDC-ZrC ceramic as a microwave absorbing material, optimize the dielectric constant of PDC-ZrC, and improve its microwave absorption performance. Attached Figure Description

[0025] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1a A scanning electron microscope image of raw Al2O3 chopped fiberboard;

[0027] Figure 1b Scanning electron microscope images of sintered ZrC precursor solutions after different impregnation times;

[0028] Figure 2a Optical photograph of Al2O3 chopped fiberboard;

[0029] Figure 2b Optical photograph of the cut chopped fiberboard;

[0030] Figure 2c Optical photograph of Al2O3 fiber reinforced ZrC microwave absorbing composite material;

[0031] Figure 3 The graph shows the variation of reflection loss (RL) of Al2O3 fiber-reinforced ZrC microwave absorbing composite material with frequency and thickness. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0034] The preparation method of the Al2O3 fiber reinforced ZrC microwave absorbing composite material of the present invention includes the following steps:

[0035] Using Al2O3 chopped fiberboard as a framework, a PDC-ZrC ceramic composite material is obtained, wherein the density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.4-0.6 g / cm³. 3 The density of the ceramic composite material in Al2O3 fiber-reinforced ZrC microwave absorbing composites is 2.1-2.5 g / cm³. 3 .

[0036] Specifically, the following steps are included:

[0037] 1) Use a utility knife and file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test;

[0038] 2) The cut Al2O3 short fiber board is placed in ZrC liquid phase ceramic precursor, and then impregnated in a vacuum environment for 1-2 hours. Then it is dried at 150℃-200℃ for 2-3 hours to obtain Al2O3 short fiber-polymer converted ZrC preform.

[0039] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then the process is repeated 2-4 times to obtain a pre-sintered sample;

[0040] 4) Place the pre-sintered sample into a heat treatment furnace with resistance wire as the heating element, and then raise the furnace temperature from room temperature to 1000-1200℃ at a heating rate of 3-10℃ / min in a flowing Ar atmosphere, and then raise the furnace temperature to 1500-1600℃ at a heating rate of 3-10℃ / min. Hold the temperature for 1-4 hours, and then turn off the power and let it cool naturally to room temperature.

[0041] 5) Repeat steps 2 to 4) twice to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0042] Example 1

[0043] The preparation method of the Al2O3 short-cut fiber-ZrC microwave absorbing composite material described in this embodiment includes the following steps:

[0044] 1) Cut Al2O3 chopped fiberboard into test samples for microwave absorption performance;

[0045] 2) The sample was placed in the ZrC liquid-phase ceramic precursor and then impregnated in the liquid phase for 2 hours under vacuum. Then it was dried in an oven at 160°C for 2 hours to obtain Al2O3 short-cut fiber-polymer-converted ZrC preform.

[0046] 3) Use Al2O3 short-cut fiber-polymer conversion ZrC preform as a sample, repeat step 2) 3 times to obtain a pre-sintered sample;

[0047] 4) Place the pre-sintered sample into a heat treatment furnace with resistance wire as the heating element, and then raise the furnace temperature from room temperature to 1000℃ in a flowing Ar atmosphere at a heating rate of 10℃ / min, then raise the temperature to 1500℃ at a heating rate of 4℃ / min, hold the temperature for 2 hours, and then cool naturally to room temperature.

[0048] 5) Repeat steps 2) to 4) twice to obtain Al2O3 short-cut fiber-ZrC microwave absorbing composite material.

[0049] Example 2

[0050] The preparation method of the Al2O3 short-cut fiber-ZrC microwave absorbing composite material described in this embodiment includes the following steps:

[0051] 1) Cut Al2O3 chopped fiberboard into test samples for microwave absorption performance;

[0052] 2) The sample was placed in the ZrC liquid-phase ceramic precursor and then impregnated in the liquid phase for 1.5 h in a vacuum environment. Then it was dried in an oven at 80 °C for 2 h to obtain Al2O3 short-cut fiber-polymer-converted ZrC preform.

[0053] 3) Use Al2O3 short-cut fiber-polymer conversion ZrC preform as a sample, repeat step 2) 3 times to obtain a pre-sintered sample;

[0054] 4) Place the pre-sintered sample into a heat treatment furnace with resistance wire as the heating element, and then raise the furnace temperature from room temperature to 1100℃ in a flowing Ar atmosphere at a heating rate of 10℃ / min, and then raise the temperature to 1450℃ at a heating rate of 4℃ / min. Hold the temperature for 2 hours, and then let it cool naturally to room temperature.

[0055] 5) Repeat steps 2) to 4) twice to obtain Al2O3 short-cut fiber-ZrC microwave absorbing composite material.

[0056] Example 3

[0057] The preparation method of the Al2O3 short-cut fiber-ZrC microwave absorbing composite material described in this embodiment includes the following steps:

[0058] 1) Cut Al2O3 chopped fiberboard into test samples for microwave absorption performance;

[0059] 2) The sample was placed in the ZrC liquid-phase ceramic precursor and then impregnated in the liquid phase for 1 hour under vacuum. Then it was dried in an oven at 150°C for 2 hours to obtain Al2O3 short-cut fiber-polymer-converted ZrC preform.

[0060] 3) Use Al2O3 short-cut fiber-polymer conversion ZrC preform as a sample, repeat step 2) 3 times to obtain a pre-sintered sample;

[0061] 4) Place the pre-sintered sample into a heat treatment furnace with resistance wire as the heating element, and then raise the furnace temperature from room temperature to 1200℃ in a flowing Ar atmosphere at a heating rate of 10℃ / min, and then raise the temperature to 1600℃ at a heating rate of 4℃ / min. Hold the temperature for 2 hours, and then let it cool naturally to room temperature.

[0062] 5) Repeat steps 2) to 4) twice to obtain Al2O3 short-cut fiber-ZrC microwave absorbing composite material.

[0063] Depend on Figure 1a and Figure 1bIt is known that PDC-ZrC exists in the voids of Al2O3 chopped fiberboard, and gradually fills the voids with increasing impregnation cycles; Figure 2a , Figure 2b and Figure 2c It can be seen that the sample changed from white to black, indicating that PDC-ZrC had been fully introduced into the interior of the Al2O3 chopped fiberboard; from Figure 3 It can be seen that the composite material has good wave absorption performance, and the effective absorption bandwidth (RL<-10dB) can reach 9.7GHz.

[0064] Example 4

[0065] The preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a framework, the Al2O3 chopped fiberboard is composited with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material, wherein the density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.4 g / cm³. 3 The density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite is 2.1 g / cm³. 3 .

[0066] Specifically, the following steps are included:

[0067] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0068] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0069] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0070] 4) The pre-sintered sample is subjected to heat treatment;

[0071] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0072] In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

[0073] The soaking time in step 2) is 1 hour;

[0074] The drying temperature in step 2) is 150℃ and the drying time is 2 hours.

[0075] In step 3), N1 is 2.

[0076] The operation process for step 4) is as follows:

[0077] The pre-sintered sample was placed in a heat treatment furnace, and then the furnace temperature was raised from room temperature to 1000℃ at a heating rate of 3℃ / min in a flowing Ar atmosphere, and then raised to 1500℃ at a heating rate of 3℃ / min. The temperature was then held for 1 hour, and then naturally cooled to room temperature.

[0078] N2 is 2.

[0079] Example 5

[0080] The preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a framework, the Al2O3 chopped fiberboard is composited with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material, wherein the density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.6 g / cm³. 3 The density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite is 2.5 g / cm³. 3 .

[0081] Specifically, the following steps are included:

[0082] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0083] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0084] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0085] 4) The pre-sintered sample is subjected to heat treatment;

[0086] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0087] In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

[0088] The soaking time in step 2) is 2 hours;

[0089] The drying temperature in step 2) is 200℃ and the drying time is 3 hours.

[0090] In step 3), N1 is 4.

[0091] The operation process for step 4) is as follows:

[0092] The pre-sintered sample was placed in a heat treatment furnace, and then the furnace temperature was raised from room temperature to 1200°C at a rate of 10°C / min in a flowing Ar atmosphere, and then raised to 1600°C at a rate of 10°C / min. The temperature was then held for 4 hours and then naturally cooled to room temperature.

[0093] N2 is 2.

[0094] Example 6

[0095] The preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a framework, the Al2O3 chopped fiberboard is composited with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material, wherein the density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.5 g / cm³. 3 The density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite is 2.3 g / cm³. 3 .

[0096] Specifically, the following steps are included:

[0097] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0098] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0099] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0100] 4) The pre-sintered sample is subjected to heat treatment;

[0101] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0102] In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

[0103] The soaking time in step 2) is 1.5 hours;

[0104] The drying temperature in step 2) is 180℃ and the drying time is 2.5h.

[0105] In step 3), N1 is 3.

[0106] The operation process for step 4) is as follows:

[0107] The pre-sintered sample was placed in a heat treatment furnace, and then the furnace temperature was raised from room temperature to 1100°C at a rate of 8°C / min in a flowing Ar atmosphere, and then raised to 1550°C at a rate of 8°C / min. The temperature was then held for 3 hours and then allowed to cool naturally to room temperature.

[0108] N2 is 2.

[0109] Example 7

[0110] The preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a frame, the Al2O3 chopped fiberboard is combined with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material.

[0111] The density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.5 g / cm³. 3 .

[0112] The density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite is 2.5 g / cm³. 3 .

[0113] Specifically, the following steps are included:

[0114] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0115] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0116] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0117] 4) The pre-sintered sample is subjected to heat treatment;

[0118] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0119] In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

[0120] The soaking time in step 2) is 1 hour;

[0121] The drying temperature in step 2) is 200℃ and the drying time is 2h.

[0122] In step 3), N1 is 4.

[0123] The operation process for step 4) is as follows:

[0124] The pre-sintered sample was placed in a heat treatment furnace, and then the furnace temperature was raised from room temperature to 1000℃ at a heating rate of 3℃ / min in a flowing Ar atmosphere, and then raised to 1500℃ at a heating rate of 10℃ / min. The sample was then held at this temperature for 4 hours and then allowed to cool naturally to room temperature.

[0125] N2 is 2.

[0126] Example 8

[0127] The preparation method of the Al2O3 fiber-reinforced ZrC microwave absorbing composite material of the present invention includes the following steps: using Al2O3 chopped fiberboard as a frame, the Al2O3 chopped fiberboard is combined with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material.

[0128] The density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.4 g / cm³. 3 .

[0129] The density of the ceramic composite material in the Al2O3 fiber-reinforced ZrC microwave absorbing composite is 2.1 g / cm³. 3 .

[0130] Specifically, the following steps are included:

[0131] 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard;

[0132] 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform.

[0133] 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample;

[0134] 4) The pre-sintered sample is subjected to heat treatment;

[0135] 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

[0136] In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

[0137] The soaking time in step 2) is 1 hour;

[0138] The drying temperature in step 2) is 200℃ and the drying time is 2h.

[0139] In step 3), N1 is 2.

[0140] The operation process for step 4) is as follows:

[0141] The pre-sintered sample was placed in a heat treatment furnace, and then the furnace temperature was raised from room temperature to 1000℃ at a heating rate of 10℃ / min in a flowing Ar atmosphere, and then raised to 1600℃ at a heating rate of 10℃ / min. The temperature was then held for 1 hour, and then naturally cooled to room temperature.

[0142] N2 is 2.

[0143] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0144] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0145] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an Al2O3 fiber-reinforced ZrC microwave absorbing composite material, characterized in that, Includes the following steps: Using Al2O3 chopped fiberboard as a framework, Al2O3 chopped fiberboard is combined with PDC-ZrC ceramic to obtain the Al2O3 fiber-reinforced ZrC microwave absorbing composite material. The density of the Al2O3 chopped fiberboard in the Al2O3 fiber-reinforced ZrC microwave absorbing composite material is 0.4-0.6 g / cm³. 3 ; The density of the ceramic composite material in Al2O3 fiber-reinforced ZrC microwave absorbing composites is 2.1-2.5 g / cm³. 3 ; Specifically, the following steps are included: 1) Cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test to obtain the cut Al2O3 chopped fiberboard; 2) The cut Al2O3 short fiber board is placed into the ZrC liquid phase ceramic precursor, then impregnated in a vacuum environment, and then dried to obtain the Al2O3 short fiber-polymer conversion ZrC preform. 3) The Al2O3 short fiber-polymer is converted into ZrC preform as the cut Al2O3 short fiber board, and then transferred to step 2) N1 times to obtain a pre-sintered sample; 4) The pre-sintered sample is subjected to heat treatment; 5) Repeat steps 2 to 4) N2 times to obtain Al2O3 fiber reinforced ZrC microwave absorbing composite material.

2. The preparation method of the Al2O3 fiber reinforced ZrC microwave absorbing composite material according to claim 1, characterized in that, In step 1), use a utility knife and a file to cut the Al2O3 chopped fiberboard into the shape required for the microwave absorption test.

3. The preparation method of the Al2O3 fiber reinforced ZrC microwave absorbing composite material according to claim 1, characterized in that, The soaking time in step 2) is 1-2 hours; The drying temperature in step 2) is 150℃-200℃, and the drying time is 2-3 hours.

4. The preparation method of the Al2O3 fiber reinforced ZrC microwave absorbing composite material according to claim 1, characterized in that, In step 3), N1 is 2, 3, or 4.

5. The preparation method of the Al2O3 fiber reinforced ZrC microwave absorbing composite material according to claim 1, characterized in that, The operation process for step 4) is as follows: The pre-sintered sample is placed in a heat treatment furnace, and then the furnace temperature is raised from room temperature to 1000-1200℃ at a heating rate of 3-10℃ / min in a flowing Ar atmosphere, and then raised to 1500-1600℃ at a heating rate of 3-10℃ / min. The temperature is then held for 1-4 hours and then naturally cooled to room temperature.

6. The method for preparing the Al2O3 fiber-reinforced ZrC microwave absorbing composite material according to claim 1, characterized in that, N2 is 2.

7. An Al2O3 fiber-reinforced ZrC microwave absorbing composite material, characterized in that, It was prepared according to the preparation method of Al2O3 fiber reinforced ZrC microwave absorbing composite material according to any one of claims 1-6.

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