A multi-component oxide-reinforced zirconium boride-polymer conversion ceramic-based absorbing material and its preparation method

Abstract

The present invention discloses a multi-component oxide-enhanced zirconium boride-polymer-converted ceramic-based absorbing material and a preparation method thereof. The method comprises ball-milling zirconium oxide, hafnium oxide, cerium oxide, titanium oxide, and tantalum pentoxide in equal molar proportions, and preparing a multi-component oxide solid solution after hot pressing and sintering; the oxide solid solution is ball-milled and uniformly dispersed with ZrB2 powder in liquid polysiloxane, and the multi-component oxide-enhanced zirconium boride-polymer-converted silicon-oxygen-carbon ceramic composite is prepared by low-temperature crosslinking and high-temperature cracking. The ceramic composite material of the present invention effectively improves the thermal stability of PDC-SiOC ceramics, improves the current situation of insufficient loss capacity when used as an electromagnetic wave absorbing material, regulates its dielectric properties, and regulates its absorption bandwidth to almost cover the entire X-band.

Description

Technical Field

[0001] The invention belongs to the technical field of wave-absorbing materials, and relates to a multi-component oxide-reinforced zirconium boride-polymer conversion ceramic-based wave-absorbing material and a preparation method thereof. Background Art

[0002] With the development of all-around radar detection technology, the problem of broadband stealth in the hot end of aircraft in extreme high-temperature environments urgently needs to be solved. However, due to the harsh service environment (high-temperature oxidizing environment), absorbing materials are generally required to be resistant to high temperatures and oxidation, and have excellent electromagnetic wave absorption performance. Traditional carbon-based, metal-based, and polymer-based composites have shortcomings such as poor oxidation resistance and high-temperature demagnetization, which severely restrict their application environments. Ceramics or ceramic-based composites are one of the candidate materials for solving the above problems due to their excellent high-temperature creep resistance and chemical stability. Among them, polymer-converted ceramics (PDC) have become a potential electromagnetic wave absorption material due to their advantages such as low processing temperature, strong designability, and adjustable electromagnetic properties. However, current PDC-based ceramics are usually pyrolyzed at relatively low temperatures to meet the impedance matching with free space, which results in a low complex dielectric constant of the ceramic material and weak electromagnetic wave attenuation ability. Therefore, it is urgent to improve the loss capacity of low-temperature pyrolyzed PDC-based ceramics and their absorption performance.

[0003] Literature 1 "Zeng X, Li E, Xia G, et al. Silica-based ceramics toward electromagnetic microwave absorption [J]. Journal of the European Ceramic Society, 2021, 41 (15): 7381-7403." shows that polymer conversion ceramics (PDC) have been widely studied as absorbing materials in recent years due to their suitable dielectric loss and high heat resistance and oxidation resistance. PDC-SiOC ceramics help maintain their chemical and mechanical durability due to their unique anionic silica network. In addition, PDC-SiOC has high thermal stability and is easy to synthesize at low temperature. However, PDC-SiOC ceramics cracked at low temperature mainly exist in an amorphous form, showing the property of electromagnetic wave transmission. The dielectric loss capacity of the ceramic is relatively small. How to improve its dielectric loss capacity is a key issue that needs to be solved urgently.

[0004] Nano ZrB2 has the characteristics of large specific surface area, high melting point and high electrical conductivity, and is one of the ideal absorbers in high temperature and harsh environments.

[0005] Reference 2 “Wide-Band Tunable Microwave-Absorbing Ceramic Composites Madeof Polymer-Derived SiOC Ceramic and in Situ Partially Surface-Oxidized Ultra-High-Temperature Ceramics[J].ACS applied materials&interfaces,2019,11(49):45862-45874.” discloses a preparation method of a nano ZrB2 / ZrO2 reinforced polymer-converted silicon-oxygen-carbon ceramic composite material, which exhibits stable dielectric properties and high-temperature absorption properties. At the same time, the absorption bandwidth of the ceramic composite material reaches 13.5GHz (26.5-40GHz), which is mainly attributed to the regulation of the dielectric properties and electrical properties of SiOC ceramics by ZrB2 / ZrO2 composite nanophases. A large number of nano interfaces are introduced into the composite material, thereby enhancing the interface polarization loss effect. In addition, a conductive network is formed between the nano ZrB2, which increases the conductivity loss capacity. Although this technology enhances the wave-absorbing performance of PDC-SiOC ceramics to a certain extent, the effective absorption bandwidth is mainly concentrated in the high-frequency Ka band and has a narrow application range.

[0006] Reference 3 "Chen K, Pei X, Tang L, et al. A five-component entropy-stabilized fluorite oxide [J]. Journal of the European Ceramic Society, 2018, 38 (11): 4161-4164." The study shows that at a sintering temperature of 1500 ° C, ZrO2, HfO2, CeO2, TiO2, and SnO2 can form a single-phase solid solution. Among them, oxides such as ZrO2 and HfO2 have high melting points, high-temperature mechanical properties, excellent corrosion resistance, and high-temperature oxidation resistance. TiO2 is an excellent semiconductor material, and its electrical conductivity increases rapidly with increasing temperature, which is of great significance for high-temperature wave absorption. The solid solution composed of five components combines the advantages of each single-component oxide. The introduction of multi-component oxide ceramic particles can adjust the dielectric properties of the composite material, improve its electromagnetic wave absorption ability, and at the same time improve the high-temperature thermal stability of the ceramic composite material.

[0007] Due to the demanding service environment, SnO2 has a lower melting point than other oxides, so Ta2O5, a high-melting-point oxide, is used to replace SnO2 in the solid solution. The introduction of multi-component oxides can improve the oxidation resistance and high-temperature thermal stability of SiOC ceramics. Summary of the Invention

[0008] To enhance the high-temperature thermal stability of PDC-SiOC ceramics, address their weak loss capacity, and control their dielectric properties to achieve X-band absorption, the present invention provides a method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material. The resulting MOS-ZrB2-SiOC ceramic composite effectively improves the thermal stability of PDC-SiOC ceramics, improves their insufficient loss capacity when used as electromagnetic wave absorbers, and controls their dielectric properties to achieve an absorption bandwidth that covers nearly the entire X-band.

[0009] To achieve the above purpose, the present invention adopts the following technical means:

[0010] In a first aspect, the present invention provides a multi-component oxide-reinforced zirconium boride-polymer conversion ceramic-based absorbing material, comprising: a matrix,

[0011] The matrix comprises a ceramic composite material formed by polymer-converted SiOC, multi-component oxide solid solution MOS, and nano ZrB2 powder; wherein MOS and nano ZrB2 are uniformly distributed in the amorphous SiOC ceramic matrix;

[0012] The matrix contains amorphous SiO x C y , free carbon, multi-component oxide solid solution and nano ZrB2.

[0013] As a further improvement of the present invention, the minimum reflectivity loss of the ceramic-based absorbing material is -49.58 dB, and the maximum effective absorption band is 4.03 GHz.

[0014] In a second aspect, the present invention provides a method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material, comprising:

[0015] Take ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders, add anhydrous ethanol solution, mix evenly and dry to obtain a first mixed powder;

[0016] The first mixed powder is placed in a mold, pre-pressed and then vacuum hot-pressed. In an Ar atmosphere, the furnace temperature is raised to 1000-1400° C. at a heating rate of 10° C. / min, and then the furnace temperature is raised to 1400-1800° C. at a heating rate of 5° C. / min to obtain a multi-element oxide solid solution MOS.

[0017] After mixing MOS, nano ZrB2 and PSO, stirring and mixing them evenly; then performing a heat treatment, in a flowing Ar atmosphere, raising the furnace temperature from room temperature to 100-300°C at a heating rate of 5°C / min to obtain a cross-linked material;

[0018] The cross-linked material is ball-milled and then sieved to obtain a second mixed powder; the second mixed powder is pressed into a shape;

[0019] The formed mixed powder is subjected to a secondary heat treatment, in which the furnace temperature is raised from room temperature to 800-1300°C at a heating rate of 3-10°C / min in a flowing Ar atmosphere to obtain a MOS-ZrB2-SiOC ceramic composite material;

[0020] First, five oxides, ZrO2, HfO2, CeO2, TiO2, and Ta2O5, were used as raw materials to obtain a multi-component oxide solid solution by hot pressing and sintering. Then, the multi-component oxide solid solution, nano-ZrB2 powder, and PDC-SiOC ceramics were evenly mixed by ball milling. Finally, MOS-ZrB2-SiOC ceramic composite materials were obtained by high-temperature cracking in a heat treatment furnace.

[0021] As a further improvement of the present invention, ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders are weighed in equal molar proportions.

[0022] As a further improvement of the present invention, the mass ratio of MOS, nano ZrB2 and PSO is (1-5): (1-5): (1-5).

[0023] As a further improvement of the present invention, the pressure of the first heat treatment is 20-40 MPa, and the pressurization is performed in two steps.

[0024] As a further improvement of the present invention, the pressure of the second mixed powder during compaction is 1 to 5 kN.

[0025] As a further improvement of the present invention, the particle size of the first mixed powder is 100 to 200;

[0026] The particle size of the second mixed powder is 200 mesh.

[0027] In a third aspect, the present invention provides an application of a multi-component oxide-reinforced zirconium boride-polymer converted ceramic-based absorbing material for absorbing electromagnetic waves.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention proposes a method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material. Five oxides, ZrO2, HfO2, CeO2, TiO2, and Ta2O5, are ball-milled in equimolar proportions and then hot-pressed and sintered to form a multi-component oxide solid solution (MOS). MOS and nano-ZrB2 powders are then uniformly dispersed in a liquid polysiloxane (PSO) and crosslinked at low temperatures and then pyrolyzed at high temperatures to produce a MOS-ZrB2-SiOC ceramic composite. The introduction of MOS improves the thermal stability of the PDC-SiOC ceramic: thermogravimetric data at 1300°C in air show that the composite exhibits a lower and more stable weight loss rate compared to pure PDC-SiOC ceramic. Furthermore, the introduction of MOS and nano-ZrB2 powders modulates the dielectric constant of the PDC-SiOC ceramic, improving its loss capacity and effectively enhancing its electromagnetic wave absorption capability. With the combination of MOS and ZrB2, the electromagnetic properties of PDC-SiOC shift from wave transmission to wave absorption. The average values ​​of the real and imaginary dielectric constants of the MOS-ZrB2-SiOC ceramic composite material increase to 12.8 and 5.5, respectively. The minimum reflectivity loss is -49.58 dB, and the maximum effective absorption band (<-10 dB) is 4.03 GHz, covering nearly the entire X-band. Furthermore, the composite material prepared by this invention features low raw material cost and low sintering temperature, promising promising applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 XRD patterns and scanning electron microscope photos; (a) is the XRD pattern of the multi-component oxide after pressureless sintering and vacuum hot pressing sintering; (b) is the scanning electron microscope photo of MOS;

[0032] Figure 2 are scanning electron microscope images, where (a) is a scanning electron microscope image of the PDC-SiOC ceramic after pyrolysis, showing that the SiOC ceramic particles are at the micron level and have a smooth surface; (b), (c), and (d) are scanning electron microscope images of the MOS-ZrB2-SiOC ceramic composite material in backscattered electron and secondary electron modes, respectively;

[0033] Figure 3Thermogravimetric curves of PDC-SiOC ceramics and ceramic composites formed by adding 30% MOS in air environment;

[0034] Figure 4 The dielectric constant test curves, where (a), (b), and (c) are the dielectric real part, imaginary part, and loss tangent values ​​of MOS-ZrB2-SiOC ceramic composites with different ratios, respectively;

[0035] Figure 5 The reflection loss of the MOS-ZrB2-SiOC ceramic composite material prepared by the present invention varies with thickness and frequency; wherein (a) is the reflection loss variation with thickness, and (b) is the reflection loss variation with frequency;

[0036] Figure 6 The present invention is a flow chart of a method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0038] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0039] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0040] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0041] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0042] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0043] The first object of the present invention is to provide a method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material, such as Figure 6 Shown, including:

[0044] Take ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders, add anhydrous ethanol solution, mix evenly and dry to obtain a first mixed powder;

[0045] The first mixed powder is placed in a mold, pre-pressed and then vacuum hot-pressed. In an Ar atmosphere, the furnace temperature is raised to 1000-1400° C. at a heating rate of 10° C. / min, and then the furnace temperature is raised to 1400-1800° C. at a heating rate of 5° C. / min to obtain a multi-element oxide solid solution MOS.

[0046] After mixing MOS, nano ZrB2 and PSO, stirring and mixing them evenly; then performing a heat treatment, in a flowing Ar atmosphere, raising the furnace temperature from room temperature to 100-300°C at a heating rate of 5°C / min to obtain a cross-linked material;

[0047] The cross-linked material is ball-milled and then sieved to obtain a second mixed powder; the second mixed powder is pressed into a shape;

[0048] The formed mixed powder is subjected to secondary heat treatment, and the furnace temperature is increased from room temperature to 800-1300° C. at a heating rate of 3-10° C. / min in a flowing Ar atmosphere to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0049] The principle is to ball-mill zirconium oxide (ZrO2), hafnium oxide (HfO2), cerium oxide (CeO2), titanium oxide (TiO2), and tantalum pentoxide (Ta2O5) in equal molar proportions and then hot-press and sinter to prepare a multi-component oxide solid solution (MOS). This oxide solid solution is then evenly dispersed with ZrB2 powder in liquid polysiloxane (PSO). The resulting multi-component oxide-reinforced zirconium boride-polymer-converted silicon-oxygen-carbon ceramic composite (MOS-ZrB2-SiOC) is then cross-linked at low temperatures and pyrolyzed at high temperatures. The introduction of the multi-component oxide solid solution and ZrB2 powder enhances the thermal stability of the polymer-converted silicon-oxygen-carbon ceramic (PDC-SiOC), improves the insufficient loss capacity of the PDC-SiOC ceramic when used as an absorber, optimizes its dielectric constant, and enhances its electromagnetic wave absorption performance.

[0050] The specific scheme is: a method for preparing a multi-component oxide-reinforced zirconium boride-polymer conversion ceramic-based absorbing material, comprising the following steps:

[0051] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 6 to 12 hours, mix evenly, pass through a 100 to 200 mesh sieve, and dry for later use;

[0052] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 20-40 MPa. In an Ar atmosphere, increase the furnace temperature to 1000-1400°C at a heating rate of 10°C / min, and then increase the furnace temperature to 1400-1800°C at a heating rate of 5°C / min. Keep warm for 1-5 hours, turn off the power and cool naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0053] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 1-5:1-5:1-5, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 100-300°C at a heating rate of 5°C / min, and keep warm for 1-3 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0054] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0055] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 800-1300°C at a heating rate of 3-10°C / min and keep it at this temperature for 1-4 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0056] The MOS-ZrB2-SiOC ceramic composite material was processed into a waveguide specimen with a size of 22.86 mm × 10.16 mm × 2.00 mm for dielectric testing.

[0057] Therefore, the second object of the present invention is to provide a multi-component oxide-reinforced zirconium boride-polymer conversion ceramic-based absorbing material, comprising: a matrix,

[0058] The matrix comprises a ceramic composite material formed by polymer-converted SiOC, multi-component oxide solid solution MOS, and nano ZrB2 powder; wherein MOS and nano ZrB2 are uniformly distributed in the amorphous SiOC ceramic matrix;

[0059] The matrix contains amorphous SiO x C y , free carbon, multi-component oxide solid solution and nano ZrB2.

[0060] The present invention will be further described below with reference to examples and drawings:

[0061] Example 1:

[0062] (1) Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 6 h, mix evenly, pass through a 200 mesh sieve, and dry for later use;

[0063] (2) The uniformly mixed powders were placed in a graphite mold, pre-pressed with a cold press, and then placed in a vacuum hot pressing furnace. The hot pressing furnace pressure was set to 30 MPa. In an Ar atmosphere, the furnace temperature was raised to 1200°C at a heating rate of 10°C / min, and then raised to 1500°C at a heating rate of 5°C / min. The temperature was kept at this temperature for 2 h, and the power was turned off and the mixture was naturally cooled to room temperature to obtain a multi-oxide solid solution MOS.

[0064] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane (PSO) in a mass ratio of 4:2:4, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 160°C at a heating rate of 5°C / min and keep it warm for 2 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0065] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0066] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1000°C at a heating rate of 5°C / min and keep it at that temperature for 2 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0067] The MOS-ZrB2-SiOC ceramic composite material was processed into a waveguide specimen with a size of 22.86 mm × 10.16 mm × 2.00 mm for dielectric testing.

[0068] Example 2:

[0069] (1) Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 6 h, mix evenly, pass through a 200 mesh sieve, and dry for later use;

[0070] (2) The uniformly mixed powders were placed in a graphite mold, pre-pressed with a cold press, and then placed in a vacuum hot pressing furnace. The hot pressing furnace pressure was set to 40 MPa. In an Ar atmosphere, the furnace temperature was raised to 1300°C at a heating rate of 10°C / min, and then raised to 1500°C at a heating rate of 5°C / min. The temperature was kept at this temperature for 2 h, and the power was turned off and the mixture was naturally cooled to room temperature to obtain a multi-oxide solid solution MOS.

[0071] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 2:3:4, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 170°C at a heating rate of 5°C / min and keep it warm for 2 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0072] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0073] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1000°C at a heating rate of 5°C / min and keep it at that temperature for 2 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0074] The MOS-ZrB2-SiOC ceramic composite material was processed into a waveguide specimen with a size of 22.86 mm × 10.16 mm × 2.00 mm for dielectric testing.

[0075] Example 3:

[0076] (1) Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 12 h, mix evenly, pass through a 200 mesh sieve, and dry for later use;

[0077] (2) The uniformly mixed powders were placed in a graphite mold, pre-pressed with a cold press, and then placed in a vacuum hot pressing furnace. The hot pressing furnace pressure was set to 30 MPa. In an Ar atmosphere, the furnace temperature was raised to 1200°C at a heating rate of 10°C / min, and then raised to 1500°C at a heating rate of 5°C / min. The temperature was kept at this temperature for 2 h, and the power was turned off and the mixture was naturally cooled to room temperature to obtain a multi-oxide solid solution MOS.

[0078] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 2:1:4, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 160°C at a heating rate of 5°C / min and keep it warm for 2 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0079] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0080] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1000°C at a heating rate of 5°C / min and keep it at that temperature for 2 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0081] The MOS-ZrB2-SiOC ceramic composite material was processed into a waveguide specimen with a size of 22.86 mm × 10.16 mm × 2.00 mm for dielectric testing.

[0082] Figure 1The XRD patterns and scanning electron microscope photos are shown in Figure 2. (a) shows the XRD patterns of multi-component oxides after pressureless sintering and vacuum hot pressing. Analysis shows that the composition of pressureless sintered ceramics is complex, and the solid solution of oxides occurs between the two phases. The ceramics after hot pressing are fluorite structure solid solutions, and the diffraction peak crystal plane indices are composed of (111), (200), (220), (311), and (222), achieving the purpose of solid solution. (b) is a scanning electron microscope photo of MOS, showing that the ceramic sample after hot pressing is densely sintered, with an average grain size of 5 to 7 μm.

[0083] Figure 2 The figures are scanning electron microscope photos, where (a) is a scanning electron microscope photo of the PDC-SiOC ceramic after cracking. It can be seen that the SiOC ceramic particles are at the micron level and have a smooth surface. (b), (c, d) are scanning electron microscope photos of the MOS-ZrB2-SiOC ceramic composite material in backscattered electron and secondary electron modes, respectively. It can be seen that MOS and nano-ZrB2 powders are evenly distributed in the PDC-SiOC ceramic matrix. Figure 3 Thermogravimetric curves of the PDC-SiOC ceramic and a ceramic composite formed by adding 30% MOS in air. The pure PDC-SiOC ceramic begins to gain weight at 600°C, reaches a maximum at 850°C, and then exhibits a dramatic weight loss. The addition of MOS significantly improves the thermal stability of the ceramic composite, with slight weight loss observed above 800°C. The addition of 30% MOS further enhances the thermal stability of the ceramic composite.

[0084] Figure 4 The following is a dielectric constant test curve for MOS-ZrB2-SiOC ceramic composites with different ratios: MOS:ZrB2:SiOC = 2:1:4; 2:2:4; 2:3:4; and 2:4:4. 2:1:4 corresponds to Example 3, 2:4:4 corresponds to Example 1, and the remaining ratios are not listed in the examples. a, b, and c are the real and imaginary dielectric constants and loss tangent values ​​of the MOS-ZrB2-SiOC ceramic composites with different ratios, respectively. The introduction of MOS and nano-ZrB2 powder significantly modulates the dielectric constant of the PDC-SiOC ceramic. The average real part of the dielectric constant of the ceramic composite increases to 12.8, and the imaginary part increases to 5.5, transforming the electromagnetic properties from wave transmission to wave absorption.

[0085] Figure 5The reflection loss of the MOS-ZrB2-SiOC ceramic composite prepared in Example 2 of the present invention (MOS:ZrB2:SiOC = 2:3:4) varies with thickness and frequency. (a) shows the reflection loss as a function of thickness, and (b) shows the reflection loss as a function of frequency. Using -10dB as the standard for effective absorption, the MOS-ZrB2-SiOC ceramic composite has an effective absorption bandwidth of 4.03GHz, and a minimum reflection loss of -49.58dB, meaning 99.99% of the electromagnetic waves are absorbed.

[0086] Example 4

[0087] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 6 hours, mix evenly, pass through a 100 mesh sieve, and dry for later use;

[0088] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 20 MPa. In an Ar atmosphere, raise the furnace temperature to 1000°C at a heating rate of 10°C / min, and then raise the furnace temperature to 1400°C at a heating rate of 5°C / min. Keep warm for 1 to 5 hours, turn off the power and cool it naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0089] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 5:1:2, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 300°C at a heating rate of 5°C / min and keep it warm for 3 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0090] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0091] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 900°C at a heating rate of 3°C / min and keep it at that temperature for 1 hour. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0092] Example 5

[0093] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 8 hours, mix evenly, pass through a 100 mesh sieve, and dry for later use;

[0094] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 30 MPa. In an Ar atmosphere, raise the furnace temperature to 1300°C at a heating rate of 10°C / min, and then raise the furnace temperature to 1600°C at a heating rate of 5°C / min. Keep warm for 3 hours, turn off the power and cool it naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0095] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 2:2:1, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 200°C at a heating rate of 5°C / min and keep it warm for 2 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0096] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0097] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1100°C at a heating rate of 10°C / min and keep it warm for 4 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0098] Example 6

[0099] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 7 hours, mix evenly, pass through a 150 mesh sieve, and dry for later use;

[0100] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 40 MPa. In an Ar atmosphere, raise the furnace temperature to 1400°C at a heating rate of 10°C / min, and then raise the furnace temperature to 1800°C at a heating rate of 5°C / min. Keep warm for 5 hours, turn off the power and cool it naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0101] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 4:2:3, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 250°C at a heating rate of 5°C / min and keep it warm for 2.5 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0102] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0103] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1100°C at a heating rate of 8°C / min and keep it at that temperature for 2 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0104] Example 7

[0105] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 10 hours, mix evenly, pass through a 100 mesh sieve, and dry for later use;

[0106] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 25 MPa. In an Ar atmosphere, raise the furnace temperature to 1200°C at a heating rate of 10°C / min, and then raise the furnace temperature to 1500°C at a heating rate of 5°C / min. Keep warm for 2 hours, turn off the power and cool it naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0107] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 1:1:1, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 150°C at a heating rate of 5°C / min and keep it warm for 1 hour; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0108] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0109] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1000°C at a heating rate of 4°C / min and keep it warm for 3 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0110] Example 8

[0111] Step 1: Weigh five kinds of ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders in equal molar proportions, add appropriate amount of anhydrous ethanol solution and ball mill for 12 hours, mix evenly, pass through a 200 mesh sieve, and dry for later use;

[0112] Step 2: Place the above-mentioned uniformly mixed powder into a graphite mold, pre-press it with a cold press, and then place it in a vacuum hot pressing furnace. Set the hot pressing furnace pressure to 35 MPa. In an Ar atmosphere, raise the furnace temperature to 1300°C at a heating rate of 10°C / min, and then raise the furnace temperature to 1700°C at a heating rate of 5°C / min. Keep warm for 4.5 hours, turn off the power and cool it naturally to room temperature to obtain a multi-oxide solid solution MOS.

[0113] Step 3: Weigh MOS, nano-ZrB2, and liquid polysiloxane solution (PSO) in a mass ratio of 5:4:5, mix MOS, nano-ZrB2 and PSO, and stir magnetically for 12 hours; put the evenly mixed sample into a heat treatment furnace with a resistance wire as the heating element, and in a flowing Ar atmosphere, increase the furnace temperature from room temperature to 300°C at a heating rate of 5°C / min and keep it warm for 3 hours; turn off the power and cool naturally to room temperature to obtain a cross-linked sample.

[0114] Step 4: The cross-linked sample is ball-milled in a planetary ball mill and then sieved to obtain a 200-mesh mixed powder; the mixed powder is pressed into a square sample with a size of 30 mm × 20 mm × 2 mm using a hydraulic press;

[0115] Step 5: Place the square sample in a heat treatment furnace with a resistance wire as the heating element. In a flowing Ar atmosphere, increase the furnace temperature from room temperature to 1100°C at a heating rate of 8°C / min and keep it warm for 3 hours. Turn off the power and cool it naturally to room temperature to obtain a MOS-ZrB2-SiOC ceramic composite material.

[0116] The third object of the present invention is to provide an application of a multi-component oxide-reinforced zirconium boride-polymer converted ceramic-based absorbing material for absorbing electromagnetic waves.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material, characterized in that: include: Take ZrO2, HfO2, CeO2, TiO2, Ta2O5 powders, add anhydrous ethanol solution, evenly ball-mill and mix, and dry to obtain a first mixed powder; The first mixed powder is placed in a mold, pre-pressed and then vacuum hot-pressed. In an Ar atmosphere, the furnace temperature is raised to 1000-1400° C. at a heating rate of 10° C. / min, and then the furnace temperature is raised to 1400-1800° C. at a heating rate of 5° C. / min to obtain a multi-element oxide solid solution MOS. After mixing MOS, nano ZrB2 and PSO, stirring and mixing them evenly; then performing a heat treatment, in a flowing Ar atmosphere, raising the furnace temperature from room temperature to 100-300°C at a heating rate of 5°C / min to obtain a cross-linked material; The cross-linked material is ball-milled and then sieved to obtain a second mixed powder; the second mixed powder is pressed into a shape; The formed mixed powder is subjected to a secondary heat treatment, in which the furnace temperature is raised from room temperature to 800-1300°C at a heating rate of 3-10°C / min in a flowing Ar atmosphere to obtain a MOS-ZrB2-SiOC ceramic composite material; Multi-component oxide reinforced zirconium boride-polymer conversion ceramic-based absorbing material, comprising: a matrix, The matrix includes a ceramic composite material formed by polymer-converted SiOC, multi-component oxide solid solution MOS, and nano ZrB2 powder; Among them, MOS and nano ZrB2 are evenly distributed in the amorphous SiOC ceramic matrix; The matrix contains amorphous SiO x C y , free carbon, multi-component oxide solid solution and nano ZrB2.

2. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The ceramic-based absorbing material has a minimum reflectivity loss of -49.58 dB and a maximum effective absorption band of 4.03 GHz.

3. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: ZrO2, HfO2, CeO2, TiO2, and Ta2O5 powders were weighed in equal molar proportions.

4. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The mass ratio of MOS, nano ZrB2 and PSO is (1~5):(1~5):(1~5).

5. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The pressure of the first heat treatment is 20-40 MPa, and the pressure is applied twice.

6. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The pressure of the second mixed powder compaction is 1 to 5 kN.

7. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The particle size of the first mixed powder is 100-200 meshes.

8. The method for preparing the multi-component oxide-reinforced zirconium boride-polymer-converted ceramic-based absorbing material according to claim 1, characterized in that: The particle size of the second mixed powder is 200 mesh.

9. Application of the multi-component oxide-reinforced zirconium boride-polymer converted ceramic-based absorbing material prepared by the preparation method of claim 1, characterized in that: Used to prepare materials that absorb electromagnetic waves.

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