A wave-absorbing material and a preparation method thereof

Abstract

The application provides a wave-absorbing material and a preparation method thereof, and the method comprises the following steps: (1) uniformly mixing an ammonium molybdate solution with nitric acid, and obtaining alpha-MoO3 powder after reaction; (2) dissolving a reducing agent powder and a metal salt powder in water to obtain a mixed solution, uniformly mixing the alpha-MoO3 powder with the mixed solution, and obtaining the wave-absorbing material after reaction. According to the scheme, the alpha-MoO3 powder is subjected to a hydrothermal reduction reaction with a mixed solution prepared by mixing a reducing agent powder and a metal salt powder, so that metal ions are inserted into the van der Waals layer of molybdenum oxide, the valence of part of molybdenum elements is lowered by replacing van der Waals force with metal ion bonds, and the conductivity and the electrochemical stability of the wave-absorbing material are improved; in addition, the volume expansion of the material caused by the metal ions entering the interlayer of molybdenum oxide endows the wave-absorbing material with a nano effect, and defects such as vacancies are formed on the surface of the material, the polarization loss is enhanced, and finally the wave-absorbing performance of the wave-absorbing material is enhanced.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing materials, and in particular to a microwave absorbing material and its preparation method. Background Technology

[0002] With the rapid development of electronic information technology, electromagnetic waves emitted by electronic information devices are gradually affecting our lives. Excessively strong electromagnetic waves can impact human health and the use of precision instruments. Therefore, people use absorbing materials to shield or reduce the adverse effects of electromagnetic waves on our lives. An ideal absorbing material should possess advantages such as strong absorption capacity, wide operating frequency band, low density, tolerance to extreme physical and chemical environments, and thinness.

[0003] In related technologies, most nanocomposite absorbing materials are prepared by modifying the surface or doping of the absorbing material, as well as changing the microstructure and structural design of the material. However, the preparation process using the above methods is complicated, and the absorbing materials obtained still have problems such as poor absorption performance and narrow operating frequency band.

[0004] Therefore, based on the above problems, there is an urgent need to provide a new microwave absorbing material and its preparation method. Summary of the Invention

[0005] To address the problems of complex preparation methods for traditional microwave absorbing materials, poor absorption performance, and narrow operating frequency bands, this invention provides a microwave absorbing material and its preparation method.

[0006] In a first aspect, the present invention provides a method for preparing a microwave absorbing material, the method comprising the following steps:

[0007] (1) Mix ammonium molybdate solution with nitric acid and react to obtain α-MoO3 powder;

[0008] (2) Dissolve the reducing agent powder and the metal salt powder in water to obtain a mixed solution, mix the α-MoO3 powder with the mixed solution, and obtain the microwave absorbing material after the reaction.

[0009] Preferably, in step (1), the solvent of the ammonium molybdate solution is water, and the molar concentration of the ammonium molybdate solution is 0.031 to 0.033 mol / L; the mass-to-volume ratio of ammonium molybdate to nitric acid is (1.3 to 1.5) g: (5 to 7) mL.

[0010] Preferably, in step (1), the reaction temperature is 170–190°C and the time is 10–12 h.

[0011] Preferably, in step (1), the reaction product is further subjected to separation, washing and drying in sequence to obtain the α-MoO3 powder.

[0012] Preferably, in step (2), the volume ratio of the mixed solution to the mass ratio of the α-MoO3 powder is 1 mL: (10-20) mg.

[0013] Preferably, the reducing agent powder is tartaric acid powder, and the metal salt powder is zinc chloride powder.

[0014] Preferably, in the mixed solution, the mass ratio of tartaric acid to zinc chloride is (1-2):(1-2).

[0015] Preferably, in step (2), the concentration of the metal salt in the mixed solution is 15 to 45 g / L.

[0016] Preferably, in step (2), the reaction temperature is 80-100°C and the time is 12-20 hours.

[0017] Secondly, the present invention provides a microwave absorbing material, which is prepared by any of the preparation methods described in the first aspect above.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] In this invention, molybdenum ions in an ammonium molybdate solution are first oxidized with nitric acid to obtain α-MoO3 powder. Then, a hydrothermal reduction reaction is carried out on a mixed solution prepared by α-MoO3 powder, reducing agent powder, and metal salt powder, thereby inserting metal ions into the van der Waals layer of molybdenum oxide. The metal ionic bonds replace the van der Waals forces, thus lowering the valence state of some molybdenum elements, thereby improving the conductivity and electrochemical stability of the microwave absorbing material. In addition, the entry of metal ions into the interlayer of molybdenum oxide causes the volume expansion of the material, thus endowing the microwave absorbing material with a nano-effect and forming defects such as vacancies on the material surface, which enhances polarization loss and ultimately enhances the microwave absorption performance of the microwave absorbing material. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a scanning electron microscope (SEM) image of an absorbing material provided in Embodiment 1 of the present invention;

[0022] Figure 2 This is an XRD pattern of a microwave absorbing material provided in Embodiment 1 of the present invention;

[0023] Figure 3 This is an XRD pattern comparing a microwave absorbing material provided in Embodiment 1 of the present invention with standard card No. 76-1003, wherein the (020) main peak on the standard card is located at 12.8 degrees;

[0024] Figure 4 This is an XRD pattern comparing a microwave absorbing material provided in Embodiment 1 of the present invention with a standard card No. 76-1003, wherein the (040) main peak on the standard card is located at 25.7 degrees;

[0025] Figure 5 This is an XRD pattern comparing a microwave absorbing material provided in Embodiment 1 of the present invention with a standard card No. 76-1003, wherein the (060) main peak on the standard card is located at 38.9 degrees;

[0026] Figure 6 This is a reflection loss diagram of a microwave absorbing material provided in Embodiment 1 of the present invention under the condition of a filling amount of 80%;

[0027] Figure 7 This is an XRD pattern of α-MoO3 powder in a microwave absorbing material provided in Example 1 of this invention;

[0028] Figure 8 This is a SEM image of α-MoO3 powder in a microwave absorbing material provided in Example 1 of this invention;

[0029] Figure 9 This is a scanning electron microscope (SEM) image of an absorbing material provided in Embodiment 2 of the present invention;

[0030] Figure 10 This is an XRD pattern of a microwave absorbing material provided in Embodiment 2 of the present invention;

[0031] Figure 11 This is a reflection loss diagram of a microwave absorbing material provided in Embodiment 2 of the present invention under the condition of a filling amount of 80%;

[0032] Figure 12 This is a scanning electron microscope (SEM) image of an absorbing material provided in Embodiment 3 of the present invention;

[0033] Figure 13 This is an XRD pattern of a microwave absorbing material provided in Embodiment 3 of the present invention;

[0034] Figure 14 This is a reflection loss diagram of a microwave absorbing material provided in Embodiment 3 of the present invention under the condition of a filling amount of 80%;

[0035] Figure 15 This is a reflection loss diagram of an absorbing material provided in Comparative Example 1 of the present invention under the condition of a filling amount of 80%. Detailed Implementation

[0036] 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 some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] As mentioned above, considering the complexity and demanding requirements of existing microwave absorbing material preparation methods, and the difficulty in achieving satisfactory absorption performance and operating frequency bands for the resulting materials, this invention provides a method for preparing a microwave absorbing material, which includes the following steps:

[0038] (1) Mix ammonium molybdate solution with nitric acid and react to obtain α-MoO3 powder;

[0039] (2) Dissolve the reducing agent powder and the metal salt powder in water to obtain a mixed solution, mix the α-MoO3 powder with the mixed solution, and obtain the microwave absorbing material after the reaction.

[0040] Molybdenum compounds are widely found in nature and are abundant in my country. Molybdenum trioxide (MoO3), as a transition metal oxide, can not only withstand high temperatures and corrosion, but also has a unique synergistic effect of dielectric loss and magnetic loss, which is beneficial for impedance matching. However, molybdenum oxide has poor conductivity, and it is difficult to meet the growing demand for microwave absorption capacity by using it directly as a microwave absorbing material. Therefore, this invention considers enhancing the conductivity of molybdenum oxide to improve its conductivity loss capacity.

[0041] In this embodiment of the invention, considering that molybdenum oxide has a unique layered structure connected by van der Waals bonds, molybdenum ions in ammonium molybdate solution are first oxidized with nitric acid to obtain α-MoO3 powder. Then, the α-MoO3 powder is placed in a mixed solution prepared with reducing agent powder and metal salt powder for hydrothermal reduction reaction, thereby inserting metal ions into the van der Waals layers of molybdenum oxide. Metal cations can exist stably in the interlayer structure of molybdenum oxide in the form of ionic bonds and replace van der Waals bonds, thereby improving the conductivity and electrochemical stability of the microwave absorbing material. In addition, the entry of metal ions into the interlayer of molybdenum oxide leads to an increase in the interlayer distance of molybdenum oxide, causing the material to expand in volume and thus achieve a larger specific surface area, thereby endowing the microwave absorbing material with nano-effects and forming defects such as vacancies on the material surface. Vacancies and cations can all serve as polarization sites, enhancing dipole polarization loss, and thus enhancing the microwave absorption performance of the microwave absorbing material.

[0042] According to some preferred embodiments, in step (1), the solvent of the ammonium molybdate solution is water, and the molar concentration of the ammonium molybdate solution is 0.031 to 0.033 mol / L (for example, it can be 0.031 mol / L, 0.032 mol / L or 0.033 mol / L); the mass-to-volume ratio of ammonium molybdate to nitric acid is (1.3 to 1.5) g: (5 to 7) mL (for example, it can be 1.3 g: 5 mL, 1.4 g: 5 mL, 1.5 g: 6 mL, 1.4 g: 7 mL or 1.5 g: 7 mL).

[0043] In this embodiment of the invention, by using nitric acid to hydrothermally oxidize molybdenum ions in ammonium molybdate and strictly controlling each condition in the reaction process, a reaction product α-MoO3 with electron vacancies is formed. This facilitates the smooth insertion of metal ions into the interlayer structure of molybdenum oxide in subsequent reactions, thereby enhancing the microwave absorption performance of the absorbing material.

[0044] It should be noted that the nitric acid in the embodiments of the present invention is a concentrated nitric acid solution with a mass fraction of 68%.

[0045] According to some preferred embodiments, in step (1), the temperature of the reaction is 170 to 190°C (for example, it can be 170°C, 180°C or 190°C), and the time is 10 to 12 hours (for example, it can be 10 hours, 11 hours or 12 hours).

[0046] According to some preferred embodiments, in step (1), the reaction product is further separated, washed and dried sequentially to obtain the α-MoO3 powder.

[0047] In this embodiment of the invention, α-MoO3 is prepared by hydrothermal reaction. First, ammonium molybdate is dissolved in deionized water to prepare an ammonium molybdate solution with a certain molar concentration. Then, concentrated nitric acid is added to the ammonium molybdate solution and stirred evenly. Finally, the mixed solution is transferred to a hydrothermal reactor and subjected to hydrothermal reaction in a forced-air oven at a certain temperature. After the reaction is completed, the reactor is allowed to cool completely to room temperature. The reaction product is then separated from the supernatant to obtain a milky white viscous reaction product. The product is washed and centrifuged three times with deionized water and ethanol respectively. After drying the centrifuged product for 12 hours, α-MoO3 powder is obtained.

[0048] According to some preferred embodiments, in step (2), the volume ratio of the mixed solution to the mass ratio of the α-MoO3 powder is 1 mL: (10-20) mg (for example, it can be 1 mL: 10 mg, 1 mL: 12 mg, 1 mL: 15 mg, 1 mL: 16 mg, 1 mL: 18 mg or 1 mL: 20 mg).

[0049] In this embodiment of the invention, by effectively controlling the ratio of the sum of the volumes of the reducing agent solution and the metal salt solution to the mass of the α-MoO3 powder during the hydrothermal reduction reaction, it is beneficial for more metal ions to be embedded into the interlayer structure of the molybdenum oxide powder to enhance the dipole polarization loss, thereby significantly enhancing the microwave absorption performance of the molybdenum oxide absorbing material.

[0050] According to some preferred embodiments, in step (2), the reducing agent powder is tartaric acid powder and the metal salt powder is zinc chloride powder.

[0051] Extensive experiments have revealed that, compared to other monovalent or trivalent metal ions, when the metal ion in the metal salt powder is divalent zinc ion and the metal salt powder is zinc chloride powder, it is more conducive to the stable embedding of metal ions into the interlayer structure of molybdenum oxide, thereby enhancing the conductivity and electrochemical stability of the molybdenum oxide microwave absorbing material. In this embodiment, during the reaction process, zinc ions are embedded into the van der Waals interlayer of molybdenum oxide, and the van der Waals forces are replaced by Zn-O-Zn ionic bonds, thus lowering the valence state of some molybdenum elements, thereby improving the conductivity and electrochemical stability of the molybdenum oxide material. In addition, zinc ions have a larger radius than other metal ions, and entering the interlayer of molybdenum oxide will cause the volume expansion of the molybdenum oxide material, thereby increasing the specific surface area of ​​the molybdenum oxide material, increasing the nano-effect, and causing defects such as vacancies to form on the surface of molybdenum oxide, thus enhancing polarization loss and further enhancing the microwave absorption performance of the molybdenum oxide microwave absorbing material.

[0052] According to some preferred embodiments, in step (2), the mass ratio of tartaric acid to zinc chloride in the mixed solution is (1-2):(1-2) (for example, it can be 1:1, 1:2, 2:1 or 2:2).

[0053] According to some preferred embodiments, in step (2), the concentration of the metal salt solution in the mixed solution is 15 to 45 g / L (for example, it can be 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L or 45 g / L).

[0054] In this embodiment of the invention, the concentration of the metal salt solution mainly affects the content of metal ions embedded in the interlayer of the molybdenum oxide structure, thereby influencing the absorption performance of the final molybdenum oxide absorbing material. Preferably, the concentration of the metal salt solution is within the range described above, more preferably 15–40 g / L, which helps ensure good absorption performance of the absorbing material. For example, if the concentration of the metal salt solution is too low, the content of metal ions embedded in the interlayer of the molybdenum oxide structure will be less, thus hindering a significant enhancement of the absorbing material's absorption performance. Although increasing the concentration of the metal salt solution will result in more metal ions being embedded in the molybdenum oxide structure, excessive metal ions can alter the chemical environment during the secondary hydrothermal process, causing the molybdenum oxide to dissolve during hydrothermal treatment and thus damaging the original structure, which is also detrimental to enhancing the absorption performance of the absorbing material.

[0055] According to some preferred embodiments, in step (2), the temperature of the reaction is 80-100°C (e.g., 80°C, 85°C, 90°C, 95°C or 100°C), and the time is 12-20h (e.g., 12h, 15h, 18h or 20h).

[0056] In this embodiment of the invention, the hydrothermal reduction reaction is carried out in an air atmosphere. By controlling the temperature and time of the hydrothermal reduction reaction, it is beneficial to allow more metal ions to be successfully embedded between the molybdenum oxide structural layers. If the temperature during the reaction is too high, the molybdenum oxide structural layer will dissolve in the zinc chloride solution, which is not conducive to preparing a powdered microwave absorbing material with good microwave absorption performance and will also result in energy waste. If the temperature during the reaction is too low, it is not conducive to the embedding of metal ions into the molybdenum oxide structural layer, which is not conducive to enhancing the microwave absorption performance of the microwave absorbing material.

[0057] In summary, the preparation method of the microwave absorbing material in the embodiments of the present invention is simple, the reduction reaction has no special requirements for the atmosphere, and the hydrothermal temperature is relatively moderate. Therefore, the method is simple, has good repeatability, does not require high temperatures, is not only low in cost, but also produces microwave absorbing materials with excellent microwave absorption performance.

[0058] The present invention also provides a microwave absorbing material, which is prepared by the preparation method provided in the present invention.

[0059] To more clearly illustrate the technical solution and advantages of the present invention, the following describes in detail a microwave absorbing material and its preparation method through several embodiments.

[0060] Example 1:

[0061] (1) (NH4)6Mo7O 24• 4H2O was dissolved in deionized water to obtain an ammonium molybdate solution with a molar concentration of 0.031 mol / L. 6 mL of concentrated nitric acid was added to the ammonium molybdate solution and stirred until well mixed. The mixed solution was transferred to a 50 mL hydrothermal reactor and placed in a forced-air oven for hydrothermal reaction at 180 °C for 12 h. After the reaction was completed, the reactor was cooled to room temperature, and the supernatant was discarded to obtain a milky white viscous reactant. Finally, the reactant was washed with deionized water and ethanol and centrifuged three times in sequence. The centrifuged product was dried for 12 h to obtain α-MoO3 powder.

[0062] (2) Dissolve 2g of metal salt (zinc chloride) powder and 2g of reducing agent (tartaric acid) powder together in 70mL of deionized water to prepare a zinc chloride / tartaric acid mixed solution, wherein the concentration of the metal salt is 28.6g / L. Add 800mg of α-MoO3 powder to the mixed solution and stir until well mixed. Then place the mixed solution in a 100mL tetrachlorofluoroethylene hydrothermal tank and perform a hydrothermal reaction at 80℃ for 20h. After the reaction is completed, allow the hydrothermal tank to cool to room temperature to obtain Zn. x MoO3 powder microwave absorbing material.

[0063] Depend on Figure 7 and Figure 8 As can be seen, the α-MoO3 powder prepared in Example 1 exhibits a nanorod morphology, composed of countless disordered nanorods, and is completely consistent with the standard card No. 76-1003 in the database, indicating that the crystal phase composition of the product is α-MoO3. In addition, the X-ray diffraction peaks are sharp and have high intensity, indicating that the material has strong crystallinity.

[0064] Combination Figure 1 As can be seen from the above, the Zn prepared in Example 1 x The MoO3 powder absorbing material exhibits a nanorod morphology, indicating that the hydrothermal reaction did not alter the nanowire morphology of molybdenum trioxide. Figure 2 The results show that the absorbing material matches the standard card No. 76-1003 in the database, indicating that the crystal phase of the product remains a molybdenum trioxide structure. Furthermore, the sharp peak shape and high intensity of the visible X-ray diffraction peaks indicate strong crystallinity of the material. Specifically, through… Figures 3 to 5 As can be seen from the data, compared with the standard card No. 76-1003 in the database, the diffraction peak angles of the absorbing material at 12.8 degrees (020), 25.7 degrees (040), and 38.9 degrees (060) are negatively shifted, indicating that the insertion of zinc ions into the molybdenum oxide interlayer increases the interlayer spacing of molybdenum oxide.

[0065] Example 2:

[0066] (1) (NH4)6Mo7O 24• 4H2O was dissolved in deionized water to obtain an ammonium molybdate solution with a molar concentration of 0.032 mol / L. 7 mL of concentrated nitric acid was added to the ammonium molybdate solution and stirred until well mixed. The mixed solution was transferred to a 50 mL hydrothermal reactor and placed in a forced-air oven for hydrothermal reaction at 190 °C for 10 h. After the reaction was completed, the reactor was cooled to room temperature, and the supernatant was discarded to obtain a milky white viscous reactant. Finally, the reactant was washed with deionized water and ethanol and centrifuged three times in sequence. The centrifuged product was dried for 12 h to obtain α-MoO3 powder.

[0067] (2) Dissolve 3g of metal salt (zinc chloride) powder and 2g of reducing agent (tartaric acid) powder in 80mL of deionized water to prepare a zinc chloride / tartaric acid mixed solution, wherein the concentration of the metal salt is 37.5g / L. Add 800mg of α-MoO3 powder to the mixed solution and stir until well mixed. Then place the mixed solution in a 100mL tetrachlorofluoroethylene hydrothermal tank and perform a hydrothermal reaction at 90℃ for 20h. After the reaction is completed, allow the hydrothermal tank to cool to room temperature to obtain Zn. x MoO3 powder microwave absorbing material.

[0068] Combination Figure 9 As can be seen from the text, the Zn prepared in Example 2... x The MoO3 powder absorbing material exhibits a nanorod morphology, indicating that the hydrothermal reaction did not alter the nanowire morphology of molybdenum trioxide. Figure 10 It can be seen that the microwave absorbing material matches the standard card No. 76-1003 in the database, indicating that the crystal phase of the product remains a molybdenum trioxide structure. In addition, the X-ray diffraction peaks are sharp and have high intensity, indicating that the material has strong crystallinity.

[0069] Example 3:

[0070] (1) (NH4)6Mo7O 24 • 4H2O was dissolved in deionized water to obtain an ammonium molybdate solution with a molar concentration of 0.033 mol / L. 6 mL of concentrated nitric acid was added to the ammonium molybdate solution and stirred until well mixed. The mixed solution was transferred to a 50 mL hydrothermal reactor and placed in a forced-air oven for hydrothermal reaction at 180 °C for 12 h. After the reaction was completed, the reactor was cooled to room temperature, and the supernatant was discarded to obtain a milky white viscous reactant. Finally, the reactant was washed with deionized water and ethanol and centrifuged three times in sequence. The centrifuged product was dried for 12 h to obtain α-MoO3 powder.

[0071] (2) Dissolve 3g of metal salt (zinc chloride) powder and 1g of reducing agent (tartaric acid) powder in 70mL of deionized water to prepare a zinc chloride / tartaric acid mixed solution, wherein the concentration of the metal salt is 42.9g / L. Add 800mg of α-MoO3 powder to the mixed solution and stir until homogeneous. Then place the mixed solution in a 100mL tetrachlorofluoroethylene hydrothermal tank and perform a hydrothermal reaction at 80℃ for 20h. After the reaction is completed, allow the hydrothermal tank to cool to room temperature to obtain Zn. x MoO3 powder microwave absorbing material.

[0072] Combination Figure 12 As can be seen from the above, the Zn prepared in Example 3... x The MoO3 powder absorbing material exhibits a nanorod morphology, but the nanowire structure shows some damage, indicating that at this ratio, increasing the zinc chloride concentration leads to the collapse of the nanowire structure. Figure 13 The results show that the absorbing material matches the standard card No. 76-1003 in the database, indicating that the product retains the molybdenum trioxide structure. Furthermore, the sharp peaks and high intensities of the visible X-ray diffraction peaks indicate strong crystallinity of the material. Comparative Example 1:

[0073] (NH4)6Mo7O 24 • 4H2O was dissolved in deionized water to obtain an ammonium molybdate solution with a molar concentration of 0.031 mol / L. 6 mL of concentrated nitric acid was added to the ammonium molybdate solution and stirred until well mixed. The mixed solution was transferred to a 50 mL hydrothermal reactor and placed in a forced-air oven for hydrothermal reaction at 180 °C for 12 h. After the reaction was completed, the reactor was cooled to room temperature, and the supernatant was discarded to obtain a milky white viscous reactant. Finally, the reactant was washed with deionized water and ethanol and centrifuged three times in sequence. The centrifuged product was dried for 12 h to obtain α-MoO3 powder microwave absorbing material.

[0074] Depend on Figure 6 and Figure 15 In comparison, it can be found that the reflection loss of the absorbing material prepared in Example 1 is significantly improved compared to the molybdenum oxide absorbing material without embedded metal ions in Comparative Example 1, exhibiting excellent absorption performance; furthermore, combined with Figure 11 and Figure 14 It can be observed that as the zinc ion content increases, the improvement in reflection loss of the absorbing material first increases and then decreases.

[0075] In the above embodiments and comparative examples, the electromagnetic wave absorption performance was tested using the following method: the prepared electromagnetic wave absorbing material and paraffin were mixed by heating and stirring in a ratio of 8:2, pressed into a ring with an inner-outer diameter ratio of 3.0 / 7.0, and its electromagnetic wave absorption performance was tested after cooling.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a wave-absorbing material, characterized by, The preparation method includes the following steps: (1) Mix ammonium molybdate solution with nitric acid and react to obtain α-MoO3 powder; (2) Dissolve the reducing agent powder and the metal salt powder in water to obtain a mixed solution, mix the α-MoO3 powder with the mixed solution, and obtain the microwave absorbing material after reaction; the reducing agent powder is tartaric acid powder, and the metal salt powder is zinc chloride powder; the mass ratio of zinc chloride to tartaric acid in the mixed solution is 1.5:1; the concentration of the metal salt in the mixed solution is 35~45g / L.

2. The preparation method according to claim 1, characterized in that, In step (1), The solvent of the ammonium molybdate solution is water, and the molar concentration of the ammonium molybdate solution is 0.031~0.033 mol / L; The mass-to-volume ratio of ammonium molybdate to nitric acid is (1.3~1.5) g : (5~7) mL.

3. The preparation method according to claim 1, characterized in that, In step (1), the reaction temperature is 170~190℃ and the time is 10~12h.

4. The preparation method according to claim 1, characterized in that, In step (1), the reaction product is then separated, washed and dried sequentially to obtain the α-MoO3 powder.

5. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of the mixed solution to the mass ratio of the α-MoO3 powder is 1 mL: (10~20) mg.

6. The preparation method according to claim 1, characterized in that, In step (2), the reaction temperature is 80~100℃ and the time is 12~20h.

7. A microwave absorbing material, characterized in that, It is prepared by any one of the preparation methods according to claims 1 to 6.

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