Sodium silicate coated wave-absorbing powder material as well as preparation method and application thereof

Abstract

The invention relates to a sodium silicate coated wave-absorbing powder material and a preparation method thereof.The preparation method comprises the following preparation steps that S1, wave-absorbing powder, PEG, polyether amine, a silane coupling agent, glycerol and water are mixed and stirred to be uniform, and a mixture is prepared; s2, heating the mixture, dropwise adding a sodium silicate solution and oleic acid, adjusting the pH value, and stirring for reaction to obtain a sodium silicate coated mixture; and S3, carrying out rotary spray drying on the sodium silicate coated mixture to obtain the sodium silicate coated wave-absorbing powder material. The sodium silicate coated wave-absorbing powder material provided by the invention has broadband impedance matching stability and weather resistance.

Description

Technical Field

[0001] This application relates to a microwave absorbing material, and more specifically, to a sodium silicate-coated microwave absorbing powder material, its preparation method, and its application. Background Technology

[0002] Electromagnetic absorbing materials can absorb electromagnetic waves incident on their surface and convert them into heat or other forms of energy, effectively solving electromagnetic interference and electromagnetic radiation pollution problems. Electromagnetic absorbing powder materials are mainly composed of absorbers and binders, while insulating coating can effectively isolate magnetic powder particles, improve the resistivity of soft magnetic composite materials, enhance impedance matching, and stably maintain the high saturation magnetic flux density of metal magnetic powder. It can also provide a certain degree of protection and improve the salt spray resistance of the product.

[0003] Existing insulation coatings include single-layer inorganic coatings, single-layer organic coatings, inorganic-inorganic coatings, and inorganic-organic coatings. Among these, sodium silicate is widely used for coating magnetic powder cores due to its high insulation properties, low cost, environmental friendliness, good compatibility, and relatively simple processing. However, the molding process of magnetic powder cores often requires high molding temperatures or pressures, which can easily damage the coating layer, causing microcracks. Furthermore, film layer failure and connection failure are prone to occur under salt spray conditions, posing a challenge to the broadband impedance matching stability during use.

[0004] Therefore, providing a sodium silicate-coated microwave absorbing powder material and preparation method that can achieve better uniformity and stability, and steadily improve the broadband impedance matching stability and weather resistance of the microwave absorbing powder, has high research and development value for expanding the application scenarios of microwave absorbing powder in the field of broadband impedance matching. Summary of the Invention

[0005] To improve the broadband impedance matching stability and weather resistance of sodium silicate-coated microwave absorbing powder, this application provides a sodium silicate-coated microwave absorbing powder material, its preparation method, and its application.

[0006] In a first aspect, this application provides a sodium silicate-coated microwave absorbing powder material, comprising the following preparation steps: S1: Mix the microwave absorbing powder with PEG, polyetheramine, silane coupling agent, glycerol and water, and stir evenly to obtain a mixture; S2: Heat the mixture, add sodium silicate solution and oleic acid dropwise, adjust the pH value, and stir to react to obtain sodium silicate-coated mixture; S3: Rotary spray dry the sodium silicate-coated mixture to obtain sodium silicate-coated microwave absorbing powder material.

[0007] By taking the above steps, the microwave absorbing powder exhibits good dispersibility in the mixture, and the polyetheramine binds through the formation of certain coordination bonds, effectively improving the coating uniformity and interfacial adhesion. Preferably, the microwave absorbing powder in S1 includes the following preparation steps: mixing and ball milling the microwave absorbing powder, using ethanol as a dispersant, vacuum drying, and sieving to obtain the microwave absorbing powder.

[0008] By taking the above steps, the coating process is relatively simple. The absorbing powder is coated with a sodium silicate insulating layer, which improves broadband impedance matching and polarization loss. The increased specific surface area of ​​the absorbing powder generates more hydroxyl groups and lattice defects, providing more active sites for subsequent bonding with sodium silicate.

[0009] Preferably, the sodium silicate solution is added dropwise by first adding a low-modulus sodium silicate solution with a mass concentration of 9-11% and a modulus of 1.5-2.2, and then adding a high-modulus sodium silicate solution with a mass concentration of 19-22% and a modulus of 3.0-3.5.

[0010] Preferably, the mass ratio of PEG to polyetheramine is 1:(0.8-1.2).

[0011] Preferably, the PEG includes PEG with a molecular weight of 200-600, and the polyetheramine includes polyetheramine with a molecular weight of 300-500.

[0012] Preferably, the mass ratio of low-modulus sodium silicate solution to high-modulus sodium silicate solution is 1:(1.2-1.8).

[0013] By taking the above steps, low-modulus sodium silicate, with its shorter silica-oxygen chains and better water solubility, can combine with the active groups on the surface of the microwave absorbing powder to form a thinner "anchoring layer" to regulate the interface transition. High-modulus sodium silicate, with its poor water solubility, can slowly form a denser, hydrolysis-resistant structure outside the thin "anchoring layer," exhibiting a lower and more stable dielectric constant and a gradual change in dielectric loss with frequency, thus better matching broadband electromagnetic waves. PEG has good adsorption properties, and polyetheramine forms a certain steric hindrance on the powder surface through amino coordination, providing a dual anchoring effect. The addition of a certain mass of silane coupling agent, especially aminosilane coupling agent, enhances interfacial compatibility by binding with the hydroxyl groups on the powder surface through silica-oxygen bonds, and by binding with the organic components through amino and epoxy groups. The inventors were pleasantly surprised to discover that the addition of PEG and polyetheramine with specific molecular weights created a distribution of active segments that were both tightly connected and had a certain degree of steric hindrance on the surface. This allowed the low-modulus sodium silicate to form a good "anchoring" effect with the surface segments and active groups, resulting in a strong physical and chemical bond and preventing film peeling under subsequent salt spray conditions. Simultaneously, the appropriate control of the inner layer thickness, utilizing its slightly higher dielectric constant as a transition layer between the absorbing powder and the outer layer, reduced interface reflection. The high-modulus sodium silicate, under the action of oleic acid, slowly hydrolyzed and condensed to form a highly cross-linked Si-O-Si network. The appropriate film thickness control and dielectric constant matching with air significantly broadened the impedance matching frequency band. Furthermore, the dense outer layer better blocked salt spray penetration, resulting in superior product performance.

[0014] Preferably, S2 includes the following preparation steps: heating the mixture, adding low-modulus sodium silicate solution and oleic acid dropwise, adjusting the pH value to 6-7, stirring and reacting for 20-30 minutes, then adding high-modulus sodium silicate dropwise, adding oleic acid, adjusting the pH value to 8-9, and reacting for 40-60 minutes to obtain sodium silicate coated mixture.

[0015] Preferably, the heating temperature in S2 is 75-80℃.

[0016] By taking the above steps, the pH value is adjusted and the temperature is higher to promote the rapid reaction of low-modulus sodium silicate and slow down the hydrolysis of high-modulus sodium silicate, allowing the high-modulus sodium silicate coating layer to grow slowly. This further optimizes the uniform "anchoring" of low-modulus sodium silicate and the density of the coating layer formed by high-modulus sodium silicate. The film thickness is appropriate, neither too thick to increase the dielectric constant nor too thin to result in insufficient salt spray resistance.

[0017] Preferably, the rotary spray dryer has an inlet air temperature of 180-200℃, an outlet air temperature of 80-95℃, an atomizer speed of 18000-25000rpm, a feed rate of 15-30ml / min, a hot air speed of 1.2-1.8m / s, and a negative pressure of (-50)-(-100)Pa.

[0018] The microwave absorbing powder prepared at this time can be fully dispersed and dried, with a suitable liquid volume, and will not produce defects caused by agglomeration or uneven shrinkage of the coating layer. At the same time, the powder will not be overheated, causing micro-cracks or defects in the coating layer. The prepared sodium silicate coated microwave absorbing powder has better performance.

[0019] Secondly, this application provides a sodium silicate-coated microwave absorbing powder material, which is prepared by the above-mentioned method for preparing sodium silicate-coated microwave absorbing powder material.

[0020] In summary, this application has the following beneficial effects: This application utilizes a gradient coating of a low-modulus inner layer and a high-modulus outer layer, combined with a certain molecular weight PEG-polyetheramine to strengthen the interface and regulate the film structure. The insulating layer and the microwave absorbing powder are densely bonded and structurally stable, synergistically achieving high microwave absorption efficiency, wide bandwidth, and high weather resistance. The preparation method is simple and the structural design is ingenious. It can be combined with inorganic-inorganic coating and inorganic-organic coating to increase the coating layer structure, has a wide range of applications, and improves the stability of sodium silicate coated microwave absorbing materials. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the preparation process of the sodium silicate-coated microwave absorbing powder material of this application. Detailed Implementation

[0022] To further aid in understanding the technical solution of this invention, several specific implementation examples are provided below to describe the technical solution of this invention in more detail. All of these described embodiments are only some embodiments of this invention, and not all of them. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments; and the reaction devices, monomer compounds, etc. involved in the following embodiments are all commercially available.

[0023] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0024] The following examples are further illustrations of the present invention, but the present invention is not limited thereto.

[0025] Iron-silicon-aluminum magnetic powder with 85wt% Fe, 9wt% Si, and 6wt% Al was purchased from Zhejiang Keda Magnetoelectric Co., Ltd. (KS039-125A); sodium silicate with a modulus of 3.1-3.4 was purchased from Jinan Shenglong Chemical Co., Ltd.; sodium silicate with a modulus of 2.0 was purchased from Dongfang Caihong brand DH-2005; polyetheramines D230 and D400 were purchased from Shandong Shengteng Chemical Co., Ltd.; PEG with a Mw380 was purchased from Polymer Standards, Inc. (PEG375); and PEG with a Mw106 was purchased from Polymer Standards, Inc. (PEG106). Example

[0026] Example 1 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG106, 15ml of D230 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, add 50ml of 20wt% sodium silicate solution with a modulus of 3.1-3.4 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, and stir the mixture at 500rpm for 1.5h to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0027] Example 2 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG106, 15ml of D230 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, add 50ml of 20wt% sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, and stir at 500rpm for 1.5h to obtain sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0028] Example 3 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG106, 15ml of D230 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 25ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 25ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 6, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0029] Example 4 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG106, 15ml of D230 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 25ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 25ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0030] Example 5 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG375, 15ml of D230 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 25ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 25ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0031] Example 6 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG375, 15ml of D375 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 25ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 25ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0032] Example 7 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG375, 10ml of D375 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 25ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 25ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0033] Example 8 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG375, 10ml of D375 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, first add 20ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, then add 30ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0034] Example 9 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG375, 10ml of D375 polyetheramine, 0.5g of silane coupling agent KH550, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 75℃, first add 20ml of a 10% (w / w) low-modulus sodium silicate solution with a modulus of 2.0 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, stir and react for 30min, cool down to 60℃, then add 30ml of a 20% (w / w) high-modulus sodium silicate solution with a modulus of 3.1-3.4 and 0.5ml of oleic acid, adjust the pH to 8, keep warm and stir at 500rpm for 60min to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0035] Comparative Example Comparative Example 1 S1: Mix 100g of iron-silicon-aluminum magnetic powder with 10ml of PEG106, 15ml of D230 polyetheramine, 2ml of glycerol and 50ml of water, and stir evenly to obtain a mixture. S2: Heat the mixture to 60℃, add 50ml of 20wt% sodium silicate solution with a modulus of 3.1-3.4 and 2ml of oleic acid, adjust the pH of the system to 6 with 0.01mol / L dilute hydrochloric acid, and stir the mixture at 500rpm for 1.5h to obtain the sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, an atomizer speed of 18000rpm, a feed rate of 20ml / min, a hot air speed of 1.5m / s, and a negative pressure of (-50)Pa to obtain sodium silicate-coated microwave absorbing powder material.

[0036] Performance testing test 1: The reflectivity of a 2mm thick product in the 10MHz frequency band was tested according to the test standard GJB2038A-2011. The test results are summarized in Table 1. Test 2: Salt spray test was conducted in accordance with test standard GJB 150.11A-2009. After 72 hours of salt spray aging, the salt spray aging reflectivity was measured again in Test 1. The percentage of reflectivity attenuation was calculated according to the formula: (reflectivity - salt spray aging reflectivity) / reflectivity. The results are summarized in Table 1.

[0037] Table 1 Reflectivity (dB) Percentage attenuation (%) Example 1 -14.1 12.1 Example 2 -13.7 15.4 Example 3 -15.1 7.2 Example 4 -15.4 6.8 Example 5 -15.2 6.7 Example 6 -15.2 6.5 Example 7 -15.8 6.1 Example 8 -16.1 5.7 Example 9 -16.6 4.3 Comparative Example 1 -13.8 19.0 As can be seen from Examples 1-4, 8-9 and Comparative Example 1 and Table 1, this application provides a method for preparing sodium silicate-coated microwave absorbing powder. First, a layer of low-modulus sodium silicate film with good adhesion is quickly coated, and then a dense high-modulus sodium silicate film is slowly coated. The resulting sodium silicate-coated microwave absorbing powder not only improves the bandwidth but also further reduces the interfacial reflection between sodium silicate and microwave absorbing powder, and also effectively improves salt spray resistance.

[0038] As can be seen from Examples 4-8 and Table 1, this application strengthens the interfacial structure by using PEG-polyetheramine with a certain molecular weight to enhance the interfacial bonding strength, resulting in better performance of the product.

[0039] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A preparation step for a sodium silicate-coated microwave absorbing powder material, characterized in that: The preparation steps include the following: S1: Mix the microwave absorbing powder with PEG, polyetheramine, silane coupling agent, glycerol and water, and stir evenly to obtain a mixture; S2: Heat the mixture, add sodium silicate solution and oleic acid dropwise, adjust the pH value, and stir the reaction to obtain sodium silicate coated mixture; S3: The sodium silicate-coated mixture is rotary spray-dried to obtain sodium silicate-coated microwave absorbing powder material.

2. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 1, characterized in that: The sodium silicate solution is added dropwise by first adding a low-modulus sodium silicate solution with a mass concentration of 9-11% and a modulus of 1.5-2.2, and then adding a high-modulus sodium silicate solution with a mass concentration of 19-22% and a modulus of 3.0-3.

5.

3. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 1, characterized in that: The mass ratio of PEG to polyetheramine is 1:(0.8-1.2).

4. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 1, characterized in that: The PEG includes PEG with a molecular weight of 200-600, and the polyetheramine includes polyetheramine with a molecular weight of 300-500.

5. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 2, characterized in that: The mass ratio of the low-modulus sodium silicate solution to the high-modulus sodium silicate solution is 1:(1.2-1.8).

6. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 1, characterized in that: The S2 includes the following preparation steps: heating the mixture, adding low-modulus sodium silicate solution and oleic acid dropwise, adjusting the pH value to 6-7, stirring and reacting for 20-30 minutes, then adding high-modulus sodium silicate dropwise, adding oleic acid, adjusting the pH value to 8-9, and reacting for 40-60 minutes to obtain sodium silicate coated mixture.

7. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 6, characterized in that: The heating temperature in S2 is 75-80℃.

8. The preparation steps of a sodium silicate-coated microwave absorbing powder material according to claim 1, characterized in that: The rotary spray dryer has an inlet air temperature of 180-200℃, an outlet air temperature of 80-95℃, an atomizer speed of 18000-25000rpm, a feed rate of 15-30ml / min, a hot air speed of 1.2-1.8m / s, and a negative pressure of (-50)-(-100)Pa.

9. A microwave absorbing powder material coated with sodium silicate, characterized in that: The sodium silicate-coated microwave absorbing powder material was prepared using the preparation method described in any one of claims 1-8.

10. An application of the sodium silicate-coated microwave absorbing powder material according to claim 9, characterized in that: The sodium silicate-coated absorbing powder material is used in electromagnetic interference suppression, stealth protection, radiation protection, and electromagnetic compatibility applications in new energy fields.

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