Medium-entropy nitride ceramic fiber wave-absorbing material and preparation method thereof

Abstract

The invention belongs to the technical field of medium-entropy nitride ceramic fibers, and particularly relates to a medium-entropy nitride ceramic fiber wave-absorbing material and a preparation method thereof. The preparation method comprises the following steps: mixing a metal source, a spinning auxiliary agent and a spinning solvent to prepare a spinning precursor solution; wherein the metal sources are selected from any three or four of a titanium source, a niobium source, a vanadium source, a cobalt source, an iron source and a nickel source; preparing precursor fibers from the spinning precursor solution through electrostatic spinning; and carrying out high-temperature heat treatment on the precursor fiber, and then carrying out reduction nitridation reaction in an ammonia gas atmosphere to obtain the medium-entropy nitride ceramic fiber wave-absorbing material. In the invention, the preparation method of the medium-entropy nitride ceramic fiber wave-absorbing material is simple to operate, and the prepared fiber has excellent microwave absorption characteristic and can be applied to the field of wave absorption.

Description

Technical Field

[0001] The invention belongs to the technical field of medium-entropy nitride ceramic fibers, and in particular relates to a medium-entropy nitride ceramic fiber absorbing material and a preparation method thereof. Background Art

[0002] With the increasingly stringent requirements for the use conditions of absorbing materials, they not only need to meet the requirements of thin thickness, low density, wide frequency band, strong absorption, and multiple spectrum bands, but also have performance indicators such as high temperature resistance, corrosion resistance, and oxidation resistance. In recent years, transition metal nitrides with high melting point, high hardness, good electrical and thermal conductivity, excellent chemical stability, and strong corrosion resistance have gradually attracted widespread attention in the field of absorbing materials.

[0003] Under the guidance of high entropy effect, lattice distortion effect, hysteresis diffusion effect and "cocktail" effect of high entropy materials, a series of high entropy oxides, high entropy carbides, high entropy borides and other materials have been successfully synthesized and proved to have application potential as microwave absorbing materials. However, due to the intrinsic differences in atomic radius, crystal structure and properties between different elements of high entropy materials, the preparation process is often complicated.

[0004] In recent years, intermediate entropy materials with fewer components have gradually attracted people's attention. Due to the lattice distortion effect of intermediate entropy materials and the complexity of their own multi-element and multi-component, the prepared materials also show interesting performance, and the synthesis difficulty is lower than that of high entropy materials, which makes the intermediate entropy regulation strategy gradually attract the attention of researchers. Intermediate entropy ceramics are a single-phase solid solution formed by three or four components in equimolar ratio or near equimolar ratio. As a new type of material, intermediate entropy ceramics show new physical, chemical and mechanical properties at room temperature and high temperature, so they are considered to be a high-temperature material with great application prospects. Since intermediate entropy ceramics are complex structures composed of a variety of anions, cations and defects in specific positions, there is a wider space for component design and performance regulation. Intermediate entropy ceramics have excellent high temperature resistance, mechanical and magnetic properties, and show extremely high hardness and elastic modulus.

[0005] In recent years, the research on intermediate entropy ceramic materials such as intermediate entropy alloys, intermediate entropy oxides, and intermediate entropy carbides has gradually expanded to the field of microwave absorption. For example, FeCoNi intermediate entropy alloys show good microwave absorption performance due to the synergistic coupling of two dielectric polarization mechanisms: dipole polarization formed after solid solution of heterogeneous atoms and conductivity loss formed by local conductive networks, as well as magnetic loss caused by natural resonance. Bi-Gd-Er intermediate entropy oxides can effectively make up for the weak absorption zone of single-component oxides and achieve common shielding of low, medium, and high-energy gamma rays. Researchers constructed (WMoCrZr)C x 、(WMoV)C x、(WMoVTi)C x Three entropy-stabilized carbides were prepared and (WMoCr)C x -ZrO 2 Complex phase entropy stabilized carbide exhibits the best microwave absorption performance, with a reflection loss of -30.88dB.

[0006] At present, there is no report on the research of preparing medium-entropy nitride ceramic fibers by electrospinning combined with reduction nitridation technology and applying them in the field of microwave absorption. The research on fibrous medium-entropy ceramic absorbers is relatively rare, mainly because there are certain barriers in its preparation technology. Unlike ordinary ceramic fibers, the preparation of medium-entropy nitride ceramic fibers requires multiple steps such as precursor fiber preparation, precursor fiber curing and reduction nitridation reaction to form nitride fibers. Improper selection of process parameters or mismatch of process parameters in any process cannot obtain medium-entropy ceramic fibers with fibrous structures. Ceramic fibers will also undergo crystallization, grain growth and shrinkage at high temperatures. For medium-entropy ceramics, the presence of multiple elements may make grain growth control more difficult. If the sintering temperature is too high or the holding time is too long, the grains may grow excessively, causing the fiber structure to become brittle and easy to break. In addition, the multi-component characteristics of medium-entropy ceramics increase the complexity of these problems, making it difficult to obtain fibrous medium-entropy ceramic absorbers with good performance.

[0007] Therefore, the present invention aims to provide a medium-entropy nitride ceramic fiber absorbing material having excellent absorbing performance and a preparation method thereof. Summary of the invention

[0008] Based on this, the purpose of the present invention is to provide a medium-entropy nitride ceramic fiber absorbing material and a preparation method thereof, which has solved the problems in the prior art.

[0009] To achieve the above object, the present invention adopts the following technical solution.

[0010] The present invention provides a medium entropy nitride ceramic fiber absorbing material and a preparation method thereof, comprising the following steps:

[0011] Mixing a metal source, a spinning aid and a spinning solvent to prepare a spinning precursor solution; wherein the metal source is selected from any three or four of a titanium source, a niobium source, a vanadium source, a cobalt source, an iron source and a nickel source;

[0012] Prepare precursor fibers by electrospinning the spinning precursor solution;

[0013] The precursor fiber is subjected to high-temperature heat treatment, and then undergoes a reduction nitridation reaction in an ammonia atmosphere to obtain a medium-entropy nitride ceramic fiber absorbing material.

[0014] In some embodiments, the titanium source includes tetrabutyl titanate, the niobium source includes niobium pentachloride, the vanadium source includes vanadium acetylacetonate, the cobalt source includes cobalt acetate, the iron source includes iron acetylacetonate, and the nickel source includes nickel acetate.

[0015] In the present invention, the metal source is selected from any three or four of a titanium source, a niobium source, a vanadium source, a cobalt source, an iron source, and a nickel source. For example, when the metal source contains three metals, the metal source is a niobium source, a vanadium source, and a titanium source; or the metal source is a niobium source, a vanadium source, and an iron source; or the metal source is a vanadium source, a cobalt source, and a titanium source; or the metal source is a vanadium source, a cobalt source, and a nickel source; or the metal source is an iron source, a vanadium source, and a cobalt source; or the metal source is an iron source, a cobalt source, and a nickel source; or the metal source is a vanadium source, an iron source, and a nickel source.

[0016] In some embodiments, the molar ratio of any three of the metal sources is 0.5-2:0.5-2:0.5-2.

[0017] When the metal source contains four metals, the metal source is a niobium source, a vanadium source, a titanium source and an iron source; or the vanadium source, the titanium source, the cobalt source and the nickel source; or the niobium source, the vanadium source, the cobalt source and the nickel source; or the niobium source, the vanadium source, the iron source and the nickel source; or the metal source is a niobium source, a vanadium source, a titanium source and a cobalt source; or the metal source is a niobium source, a titanium source, an iron source and a nickel source; or the metal source is a vanadium source, a cobalt source, an iron source and a nickel source; or the metal source is a vanadium source, a titanium source, an iron source and a nickel source; or the metal source is a vanadium source, a titanium source, an iron source and a nickel source; or the metal source is a titanium source, a cobalt source, an iron source and a nickel source.

[0018] In some embodiments, the molar ratio of any four of the metal sources is 0.5-2:0.5-2:0.5-2:0.5-2.

[0019] In some embodiments, the niobium source includes niobium pentachloride, the vanadium source includes vanadium acetylacetonate, the titanium source includes tetrabutyl titanate, the cobalt source includes cobalt acetate, the iron source includes iron acetylacetonate, and the nickel source includes nickel acetate.

[0020] Preferably, in some embodiments of the present invention, when the metal source contains three metals, the metal source is niobium pentachloride, vanadium acetylacetonate and tetrabutyl titanate, or vanadium acetylacetonate, tetrabutyl titanate and iron acetylacetonate, or vanadium acetylacetonate, cobalt acetate and tetrabutyl titanate, or vanadium acetylacetonate, cobalt acetate and nickel acetate, or cobalt acetate, nickel acetate and iron acetylacetonate.

[0021] Preferably, in some embodiments of the present invention, when the metal source contains four metals, the metal source is niobium pentachloride, vanadium acetylacetonate, iron acetylacetonate and tetrabutyl titanate, or vanadium acetylacetonate, tetrabutyl titanate, cobalt acetate and nickel acetate, or niobium pentachloride, tetrabutyl titanate, cobalt acetate and nickel acetate, or niobium pentachloride, vanadium acetylacetonate, iron acetylacetonate and nickel acetate.

[0022] The preparation method of the medium entropy nitride ceramic fiber absorbing material provided in the present invention requires that the precursor fiber obtained by electrostatic spinning undergoes a reduction nitridation reaction to obtain a nitride fiber, and the oxide corresponding to the metal source is first nitrided to form a nitride, and then solid-solution is formed to form a medium entropy nitride, which requires the same or similar reduction nitridation temperature to form. When the reduction nitridation temperature does not match, some oxides may not be nitrided, or the grains may grow too large, resulting in fiber breakage.

[0023] In some embodiments, the high temperature heat treatment is performed at a temperature of 400°C to 600°C for a treatment time of 30 min to 50 min. For example, the high temperature heat treatment is performed at a temperature of 400°C, 500°C or 600°C for a treatment time of 30 min, 40 min or 50 min.

[0024] In some embodiments, in the reduction nitridation reaction, the temperature of the reduction nitridation reaction is 700° C. to 800° C.; NH 3 The flow rate is 400 mL / min to 800 mL / min, and the reduction nitridation time is 2 hours to 3 hours. For example, the reduction nitridation reaction temperature is 700°C, 750°C or 800°C; NH 3 The flow rate is 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min or 800 mL / min; the reduction and nitridation time is 2 hours, 2.5 hours or 3 hours.

[0025] In some embodiments, the electrospinning process conditions are: the electrospinning voltage is 20 kV to 25 kV, and the solution supply rate is 1 mL / h to 1.3 mL / h. For example, the electrospinning voltage is 20 kV, 22 kV, 24 kV or 25 kV; the solution supply rate is 1 mL / h, 1.1 mL / h, 1.2 mL / h or 1.3 mL / h.

[0026] In some embodiments, the spinning aid is acetic acid and polyvinyl pyrrolidone; the spinning solvent is a mixture of anhydrous ethanol and NN dimethylformamide; the volume ratio of anhydrous ethanol to NN dimethylformamide is 5 to 1:1.

[0027] The present invention also provides a medium entropy nitride ceramic fiber wave absorbing material prepared by the above method.

[0028] In some embodiments, the cationic components in the medium-entropy nitride ceramic fiber absorbing material contain any three or four elements of niobium, vanadium, titanium, cobalt, iron and nickel; the medium-entropy nitride ceramic fiber absorbing material has a porous structure with an average diameter of about 100nm to 400nm and a pore size range of 5nm to 100nm.

[0029] Specifically, in some embodiments of the present invention, the diameter of the medium-entropy nitride ceramic fiber absorbing material is 100 nm, 130 nm, 150 nm, 170 nm, 190 nm, 230 nm, 270 nm, 330 nm, 350 nm or 400 nm.

[0030] Specifically, in some embodiments of the present invention, the pore size of the medium-entropy nitride ceramic fiber absorbing material is 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm.

[0031] In some embodiments, the medium-entropy nitride fiber is a single crystal phase, and each element is evenly distributed.

[0032] Based on the technical solution of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0033] In the present invention, electrospinning and ammonia reduction nitridation are combined to prepare medium-entropy nitride ceramic fiber absorption material. Due to the reduction in the number of components, the operation is simpler and more conducive to the simultaneous reduction nitridation to form medium-entropy nitride. It is also a method for preparing medium-entropy nitride ceramic fiber with wave-absorbing properties.

[0034] The medium entropy nitride ceramic fiber absorbing material prepared by the present invention has good absorbing properties, so that it can be applied in military, civil and industrial absorbing fields, etc., and has important practical significance and theoretical value.

[0035] The present invention provides a set of metal source combination types and ratios that conform to the principle of synchronous reduction nitridation, which can obtain precursor fibers that meet the requirements of the later preparation of medium-entropy nitride ceramic fibers through an electrospinning process. The present invention also explores the reduction nitridation temperature during the reduction nitridation process so that the principle of synchronous reduction nitridation can be met. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0037] Example 1

[0038] A method for preparing a medium-entropy nitride ceramic fiber absorbing material comprises the following steps:

[0039] 1. Preparation of spinning precursor solution: Add 15 ml of anhydrous ethanol to a beaker. Then, add three metal sources, niobium pentachloride, vanadium acetylacetonate, and tetrabutyl titanate, as well as 2 ml of acetic acid, 2 g of PVP (polyvinyl pyrrolidone), and 9 ml of DMF (N, N-dimethylformamide) to the beaker in sequence, mix well until completely dissolved, and obtain the spinning solution.

[0040] 2. Electrospinning: The solution was transferred to a plastic syringe for electrospinning to obtain precursor fibers. The electrospinning voltage was 20 kV, and the solution supply rate was set to 1 mL / h.

[0041] 3. Pre-burning: After the precursor fiber is dried in an oven at 80°C, it is pre-burned in an air atmosphere at 500°C for 30 minutes, that is, high-temperature heat treatment for 30 minutes (5°C / min).

[0042] 4. Ammonia reduction nitridation: After the pre-burned fiber is cooled to room temperature, 3 The reduced nitridation was carried out at 800°C for 2 hours (5°C / min) in an atmosphere to finally form a medium entropy nitride ceramic fiber absorber. Specifically, during the heating process of the reduced nitridation with ammonia, when the heating temperature is lower than 300°C, N 2 When the heating temperature is between 300℃ and 500℃, the flow rate of NH 3 Replaced N 2 When the reduction nitridation temperature exceeds 500°C, NH 3 The flow rate was maintained at 800 mL / min until the temperature was raised to 800 °C and kept for 2 hours, then cooled to 300 °C. Then the temperature was kept at N 2 The product is cooled to room temperature under atmosphere to finally form a medium-entropy nitride ceramic fiber absorbing material.

[0043] In this embodiment, the combination of metal sources in the precursor solution in the above preparation method was explored, and the specific raw material usage is shown in Table 1.

[0044] Table 1 Metal sources

[0045]

[0046] The medium-entropy nitride ceramic fiber absorbent material obtained by the method provided in this embodiment was observed by scanning electron microscopy. The results showed that test groups 1 to 5 could all produce the medium-entropy nitride ceramic fiber absorbent material required by the present invention, which had good crystallinity, fiber morphology, large aspect ratio, and a diameter of about 150 nm.

[0047] The reflection loss of the medium entropy nitride ceramic fiber absorber prepared in Experiments 1 to 5 with a filler amount of 20 wt % was calculated using transmission line theory. The results are shown in Table 2.

[0048] Table 2 Reflection loss

[0049]

[0050]

[0051] As shown in Table 2, it is shown that the medium entropy nitride ceramic fiber absorbing material prepared by the method provided in this embodiment has good absorbing performance, and the best combination is test group 1.

[0052] Example 2

[0053] A method for preparing a medium entropy nitride ceramic fiber absorbing material, compared with Example 1, the reaction conditions of ammonia reduction nitridation are different, and the other methods are the same. The specific method of ammonia reduction nitridation is: after the pre-sintered fiber is cooled to room temperature, the fiber is heated in NH 3 The medium entropy nitride ceramic fiber absorbent material was finally obtained by reduction nitridation at 700°C for 3 hours (5°C / min) in an atmosphere.

[0054] The transmission line theory is used to calculate the reflection loss of the medium-entropy nitride ceramic fiber absorber with a filler content of 25wt%. When the thickness of the absorbing layer is only 2mm, the optimal reflection loss reaches -42.4dB, indicating that the medium-entropy nitride ceramic fiber absorber prepared by the method provided in this embodiment has good absorbing performance.

[0055] Example 3

[0056] A method for preparing a medium-entropy nitride ceramic fiber absorbing material. Compared with Example 1, the pre-firing conditions are different, and the other methods are the same. The specific method of pre-firing is: after the precursor fiber is dried in an oven at 80°C, it is pre-firing in an air atmosphere at 600°C for 50 minutes, that is, high-temperature heat treatment for 50 minutes (5°C / min).

[0057] The transmission line theory is used to calculate the reflection loss of the medium-entropy nitride ceramic fiber absorber with a filler content of 20wt%. When the thickness of the absorbing layer is only 2.7mm, the optimal reflection loss reaches -41.4dB, indicating that the medium-entropy nitride ceramic fiber absorber prepared by the method provided in this embodiment has good absorbing performance.

[0058] Example 4

[0059] A method for preparing a medium entropy nitride ceramic fiber absorbing material. Compared with Example 1, the type and amount of the metal source are different, and the temperature of ammonia reduction nitridation is different. Specifically, this embodiment includes the following steps:

[0060] 1. Preparation of spinning precursor solution: Add 15 ml of anhydrous ethanol to a beaker. Then, add 0.45 g of niobium pentachloride, 0.45 g of vanadium acetylacetonate, 0.6 g of ferric acetylacetonate, 1 mL of acetic acid, 0.58 mL of tetrabutyl titanate, 2 g of PVP, and 9 mL of DMF to the beaker in sequence. After that, stir at room temperature until completely dissolved. The molar ratio of niobium, vanadium, iron, and titanium is 1:1:1:1.

[0061] 2. Electrospinning: Transfer the solution into a plastic syringe for electrospinning. Adjust the electrospinning voltage to 24 kV and set the solution supply rate to 0.8 mL / h.

[0062] 3. Pre-burning: After drying the fiber in an oven at 80°C, pre-burn it in air at 400°C for 30 minutes, i.e., high-temperature heat treatment for 30 minutes.

[0063] 4. Ammonia reduction nitridation: After the pre-burned fiber is cooled to room temperature, the fiber is heated in NH 3 The alloy was reductively nitrided at 700°C for 2.5 hours (5°C / min) in an atmosphere.

[0064] The transmission line theory is used to calculate the reflection loss of the medium-entropy nitride ceramic fiber absorber with a filler content of 30wt%. When the thickness of the absorbing layer is 2.4mm, the optimal reflection loss reaches -46.7dB, indicating that the medium-entropy nitride ceramic fiber absorber prepared by the method provided in this embodiment has good absorbing performance.

[0065] Example 5

[0066] A method for preparing a medium-entropy nitride ceramic fiber absorbing material. Compared with Example 4, the pre-firing conditions are different. Specifically, the pre-firing conditions are as follows: Pre-firing: After the fiber is dried in an oven at 80°C, it is pre-firing in air at 600°C for 30 minutes, that is, high-temperature heat treatment for 30 minutes.

[0067] The transmission line theory is used to calculate the reflection loss of the medium-entropy nitride ceramic fiber absorber with a filler content of 15wt%. When the thickness of the absorbing layer is 3.3mm, the optimal reflection loss reaches -32.6dB, indicating that the medium-entropy nitride ceramic fiber absorber prepared by the method provided in this embodiment has good absorbing performance.

[0068] Example 6

[0069] A method for preparing a medium entropy nitride ceramic fiber absorbing material, compared with Example 4, the electrospinning conditions are different, specifically, the electrospinning conditions are: transferring the solution to a plastic syringe for electrospinning. The electrospinning voltage is adjusted to 22 kV, and the supply rate of the solution is set to 1.3 mL / h.

[0070] The transmission line theory is used to calculate the reflection loss of the medium-entropy nitride ceramic fiber absorber with a filler content of 30wt%. When the thickness of the absorbing layer is 2.2mm, the optimal reflection loss reaches -49.5dB, indicating that the medium-entropy nitride ceramic fiber absorber prepared by the method provided in this embodiment has good absorbing performance.

[0071] Comparative Example 1

[0072] Comparative Example 1 Compared with Example 1, the difference in the preparation method is that the ratio of metal sources of the spinning precursor solution is different, and the remaining steps are the same. In this comparative example, the configuration method of the spinning precursor solution is: 15 milliliters of anhydrous ethanol are added to a beaker. Then 2g niobium pentachloride, 2g vanadium acetylacetonate, 3mL tetrabutyl titanate, 6mL acetic acid, 5g PVP and 5mLDMF are added to the beaker in sequence. Afterwards, stirring was continued for 2h at room temperature, and it was found that the above-mentioned raw materials could not be completely dissolved in anhydrous ethanol. There is a certain amount of undissolved particles deposited at the bottom of the beaker, and it can be seen that cations or PVP are used too much, and too little solvent will affect solubility. When it is subjected to electrostatic spinning, the precursor fiber collection amount is less, has a larger viscosity, and cannot be exposed.

[0073] Comparative Example 2

[0074] Compared with Example 1, the difference in the preparation method of Comparative Example 2 is that the parameters of electrospinning are: electrospinning voltage: 15 kV, solution supply rate: 0.6 mL / h. The remaining steps are the same as those in Example 1. When the medium entropy nitride ceramic fiber absorbent material is prepared. The prepared medium entropy nitride ceramic fiber (Ti 1 / 3 Nb 1 / 3 V 1 / 3 )N morphology is poor, and the fiber is severely bent and broken. It can be seen that when the spinning voltage is too low or the feeding speed is too slow, continuous fibers cannot be formed.

[0075] Comparative Example 3

[0076] Compared with Example 1, the difference in the preparation method of Comparative Example 3 is that the precursor fiber is pre-fired in air at 650°C for 60 minutes (5°C / min), that is, the high-temperature heat treatment is performed for 60 minutes. The remaining steps are the same as those in Example 1 to prepare the medium-entropy nitride ceramic fiber absorber. The prepared medium-entropy nitride ceramic (Ti 1 / 3 Nb 1 / 3 V 1 / 3 )N fiber morphology is poor, fiber bending and breakage are serious. It can be seen that too high pre-burning temperature or too long pre-burning time will lead to precursor fiber breakage.

[0077] Comparative Example 4

[0078] Comparative Example 4 Compared with Example 1, the difference in the preparation method is that the pre-burned fiber is heated in NH 3 The reduction nitridation was carried out at 850° C. for 3 hours (5° C. / min) in an atmosphere. The remaining steps were the same as those in Example 1 to prepare the medium entropy nitride ceramic fiber absorbent material.

[0079] The medium entropy nitride ceramic fiber (Ti 1 / 3 Nb 1 / 3 V 1 / 3 )N has good crystallinity, the aspect ratio is greatly reduced, and the diameter is about 400nm. The transmission line theory is used to calculate the reflection loss of the medium entropy nitride fiber / paraffin composite material with a filler content of 20wt%. When the thickness of the absorbing layer is only 1.40mm, the optimal reflection loss reaches -17.2dB. It can be seen that if the reduction nitridation temperature is too high and the insulation time is prolonged, the grain size will grow, the fiber diameter will become thicker, and the absorbing performance will decrease.

[0080] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a medium entropy nitride ceramic fiber absorbing material, characterized in that: The following steps are involved: Mixing a metal source, a spinning aid and a spinning solvent to prepare a spinning precursor solution; wherein the metal source is selected from any three or four of a titanium source, a niobium source, a vanadium source, a cobalt source, an iron source and a nickel source; Prepare precursor fibers by electrospinning the spinning precursor solution; The precursor fiber is subjected to high-temperature heat treatment, and then undergoes a reduction nitridation reaction in an ammonia atmosphere to obtain a medium-entropy nitride ceramic fiber absorbing material.

2. The preparation method according to claim 1, characterized in that The molar ratio of any three of the metal sources is 0.5-2:0.5-2:0.5-2.

3. The preparation method according to claim 1, characterized in that: The molar ratio of any four of the metal sources is 0.5-2:0.5-2:0.5-2:0.5-2.

4. The preparation method according to claim 1, characterized in that: The titanium source includes tetrabutyl titanate, the niobium source includes niobium pentachloride, the vanadium source includes vanadium acetylacetonate, the cobalt source includes cobalt acetate, the iron source includes iron acetylacetonate, and the nickel source includes nickel acetate.

5. The preparation method according to claim 1, characterized in that: The conditions of the high temperature heat treatment are: temperature 400° C. to 600° C., and treatment time 30 min to 50 min.

6. The preparation method according to claim 1, characterized in that: In the reduction nitridation reaction, the temperature of the reduction nitridation reaction is 700° C. to 800° C.; the NH 3 flow rate is 400 mL / min to 800 mL / min; and the reduction nitridation time is 2 hours to 3 hours.

7. The preparation method according to claim 1, characterized in that: The process conditions of the electrospinning are as follows: the voltage of the electrospinning is 20 kV to 25 kV, and the supply rate of the solution is 1 mL / h to 1.3 mL / h.

8. The preparation method according to claim 1, characterized in that: The spinning aids are acetic acid and polyvinyl pyrrolidone; the spinning solvent is a mixture of anhydrous ethanol and NN dimethylformamide; the volume ratio of anhydrous ethanol to NN dimethylformamide is 5 to 1:

1.

9. The medium-entropy nitride ceramic fiber absorbing material prepared by the method according to any one of claims 1 to 8.

10. The medium entropy nitride ceramic fiber absorbing material according to claim 9, characterized in that: The cationic components in the medium-entropy nitride ceramic fiber absorbing material contain any three or four elements of titanium, niobium, vanadium, cobalt, iron and nickel; the medium-entropy nitride ceramic fiber absorbing material has a porous structure with an average diameter of about 100 to 400 nm and a pore size range of 5 nm to 100 nm.

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