Air-assisted coaxial electrostatic spraying device and method for preparing aluminum-based energetic composite material by adopting same

Abstract

The invention discloses a gas-assisted coaxial electrostatic spraying device and a preparation method of an aluminum-based energetic composite material. The device comprises a gas-liquid flow conveying unit, an electrostatic generation device and a receiving plate, the gas-liquid flow conveying unit comprises an outer pipe and an inner pipe which are coaxially sleeved, and a gas flow cavity is formed between the outer pipe and the inner pipe; the inner pipe comprises a liquid passing pipe and a sprayer which are coaxially communicated, and a liquid spraying opening is formed in the front end of the sprayer; the rear end of the airflow cavity is closed, and the front end is provided with an air outlet corresponding to the liquid spraying port; a gas inlet is formed in the side wall of the outer pipe and connected with a gas conveying device through a pipeline, and the gas conveying device is used for conveying gas into the gas flow cavity; the static electricity generating device acts on the spray head so that fog drops sprayed out of the spray head can carry charges, and the fog drops can form powder on the receiving plate. The preparation of the energetic composite material based on the large-size aluminum base is realized through gas phase assistance, and the preparation efficiency of the energetic composite material is improved; and the regulation and control capability on the product granularity is improved by controlling the size of the airflow field.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, relates to the preparation of composite materials, and specifically relates to an air-assisted coaxial electrostatic spray device and a method for preparing an aluminum-based energetic composite material by using the device. Background Art

[0002] Electrostatic spraying is a method that uses electrostatic field force to disperse liquid into tiny droplets. It can be used to prepare micro-nano composite energetic materials with concentrated particle size. Among them, aluminum powder and energetic oxidant can be prepared into metastable intermolecular complex (MIC) by electrostatic spraying method. Since the reaction distance between molecules in MIC material is effectively shortened, the reaction rate and mass transfer and heat transfer process of energetic material are accelerated, thereby improving the energy release level of aluminum powder. However, due to the limited electric field intensity of electrostatic spraying technology in the spraying direction, it is difficult to generate sufficient force on large-particle micron aluminum powder. Therefore, the electrostatic spraying method is currently mainly used for the preparation of nano-aluminum powder composite energetic materials. When preparing micron aluminum powder energetic composite materials, there is a problem of low preparation efficiency, which urgently needs to be improved. Summary of the invention

[0003] In view of the above-mentioned defects and shortcomings in the prior art, the present invention provides an air-assisted coaxial electrostatic spray device and a method for preparing aluminum-based energetic composite materials using the device, so as to solve the technical problem of low efficiency in preparing micron aluminum powder composite energetic materials in the prior art.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An air-assisted coaxial electrostatic spray device comprises a gas-liquid flow conveying unit, an electrostatic generating device and a receiving plate;

[0006] The gas-liquid flow conveying unit comprises an outer tube and an inner tube coaxially sleeved, and an airflow cavity is formed between the outer tube and the inner tube; the inner tube comprises a liquid passing pipe and a nozzle coaxially connected, and a liquid spraying port is arranged at the front end of the nozzle; the rear end of the airflow cavity is closed, and an air outlet is arranged at the front end corresponding to the liquid spraying port; an air inlet is arranged on the side wall of the outer tube, and the air inlet is connected to a gas conveying device through a pipeline, and the gas conveying device is used to deliver gas into the airflow cavity;

[0007] The electrostatic generating device comprises a positive output terminal and a negative output terminal, wherein the positive output terminal is connected to the receiving plate, and the negative output terminal is connected to the nozzle; the electrostatic generating device can generate a high-voltage electrostatic field between the nozzle and the receiving plate; the droplets sprayed from the nozzle can flow from the nozzle to the receiving plate within the high-voltage electrostatic field and form powder at the receiving plate.

[0008] The present invention also has the following technical features:

[0009] Specifically, the outer tube includes a straight tube portion and a conical portion which are coaxially connected, the distance between the front end face of the conical portion and the front end face of the nozzle is 1 to 3 mm, and the distance between the front end face of the nozzle and the receiving plate is 8 to 15 cm.

[0010] Furthermore, the nozzle is in the shape of a truncated cone, the large diameter end of the nozzle is coaxially connected to the liquid passage pipe, and the cone angle of the nozzle is smaller than the cone angle of the cone portion.

[0011] Furthermore, the outer tube is electrically connected to the electrostatic generating device.

[0012] Furthermore, the outlet pressure of the gas delivery device is 0.1-0.4 MPa.

[0013] The present invention also protects a method for preparing an aluminum-based energetic composite material using the above-mentioned air-assisted coaxial electrostatic spray device, comprising the following steps:

[0014] Step 1, adding adhesive powder to a first organic solvent and stirring evenly to obtain an adhesive solution; adding micron aluminum powder to a second organic solvent, and subjecting the mixture to ultrasonic and magnetic stirring to obtain a micron aluminum powder dispersion; adding the adhesive solution to the micron aluminum powder dispersion, and subjecting the mixture to mixing and stirring to obtain a micron aluminum powder / adhesive dispersion;

[0015] Step 2, adding the powders of other components into a third organic solvent, and subjecting the mixture to ultrasonic and magnetic stirring treatment to obtain a dispersion of other components;

[0016] Step 3, mixing the other component dispersions obtained in step 2 with the micron aluminum powder dispersion obtained in step 1 to obtain a precursor dispersion;

[0017] Step 4: The nozzle is connected to the negative output terminal of the electrostatic generator, and the receiving plate is connected to the positive output terminal of the electrostatic generator, so as to establish a high-voltage electrostatic field between the nozzle and the receiving plate; the electrostatic spray parameters are set, the precursor dispersion is sent into the inner tube, and the gas is sent into the air flow cavity, and the droplets sprayed from the nozzle form an aluminum-based energetic composite material at the receiving plate;

[0018] The precursor solution includes the following raw material components by mass percentage: 5-10% of micron aluminum powder, 1-3% of binder, and 87-94% of other components.

[0019] Furthermore, the particle size of the micron aluminum powder is 1 μm to 40 μm, and the gas includes nitrogen, argon and air.

[0020] Furthermore, the adhesive is selected from one of PVDF and PVP; the first organic solvent is selected from one of DMF, methanol, ethanol and tetrahydrofuran, the second organic solvent and the third organic solvent are selected from one or both of acetone and ethanol; the other components are selected from one of Fe2O3 and MeBH.

[0021] Furthermore, in step 1, the ultrasonic treatment time is 5 to 20 minutes; in step 2, the ultrasonic treatment time is 20 to 30 minutes.

[0022] Furthermore, the electrostatic spray parameters described in step 4 include: the voltage provided by the electrostatic generating device is 16 to 23 kV, the spray rate is 8.3 to 33.3 μL / min, the receiving distance between the receiving plate and the nozzle is 8 to 15 cm, and the outlet gas pressure of the gas delivery device is 0.2 to 0.4 MPa.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The gas-assisted coaxial electrostatic spray device provided by the present invention not only realizes the preparation of large-sized aluminum-based energetic composite materials through a gas-assisted approach, but also greatly improves the preparation efficiency of energetic composite materials.

[0025] (2) The air-assisted coaxial electrostatic spray device provided by the present invention can realize the preparation of micron-sized aluminum-based energetic composite materials, which solves the dilemma that conventional electrostatic spray technology can only prepare nano-aluminum powder energetic composite materials, and further solves the technical problem that nano-aluminum powder is easy to further react with water and oxygen in the air, thereby hindering the application of composite energetic materials containing nano-aluminum powder in propellants.

[0026] (3) The method for preparing the aluminum-based energetic composite material provided by the present invention combines the coaxial electrostatic spraying technology with the gas phase assistance, which can greatly improve the preparation efficiency of the energetic composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide further understanding of the present disclosure and constitute a part of the specification. They are used to explain the present disclosure together with the following detailed description, but do not constitute a limitation of the present disclosure.

[0028] Figure 1 It is a schematic diagram of the overall structure of the air-assisted coaxial electrostatic spray device;

[0029] Figure 2 This is a SEM image of the Al / PVDF / Fe2O3 energetic composite material prepared in Example 2;

[0030] Figure 3 This is a SEM image of the Al / PVDF / Fe2O3 energetic composite material prepared in Comparative Example 1;

[0031] Figure 4 This is the SEM image of Al / PVP / MeBH prepared in Example 3;

[0032] Figure 5 This is the SEM image of Al / PVP / MeBH prepared in Comparative Example 2;

[0033] Figure 6 The combustion conditions of Al / PVP / MeBH prepared in Example 3 at the propellant combustion surface.

[0034] The symbols in the figure represent:

[0035] 1-outer tube, 2-inner tube, 3-pipeline, 4-receiving plate; 11-straight tube portion, 12-conical portion; 21-liquid passage pipe, 22-sprinkler.

[0036] The technical solution of the present invention is further described below in conjunction with embodiments. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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 any ordinary technician in the field belong to the scope of protection of the present invention.

[0038] The technical concept of the present application is: the outer tube and inner tube coaxially sleeved in the coaxial electrostatic spray device are used as the core structure, the airflow enters the airflow cavity through a pipe perpendicular to the outer tube, and contacts the precursor dispersion at the air outlet, so that the precursor dispersion droplets are atomized, and the electrostatic generating device makes the atomized droplets carry electric charge to generate electrostatic spray. The auxiliary effect provided by the airflow can significantly enhance the conveying capacity of the electrostatic spray in the spraying direction. In addition, the airflow field also helps to further fragment the droplets. By effectively combining the direct force of the electrostatic field and the airflow field on the droplets, and controlling the size of the airflow field, sufficient driving force is generated for the large-particle micron aluminum powder, so that the precursor dispersion forms a trumpet-shaped liquid phase jet under the action of the high-voltage electrostatic field. After the liquid phase jet passes the flight distance, as the solvent evaporates, it is finally deposited at the receiving plate to form an aluminum-based energetic composite material powder composed of micron-scale aluminum powder.

[0039] The scanning electron microscope images in the following embodiments were tested using a S4800 scanning electron microscope produced by Hitachi, Japan.

[0040] Unless otherwise specified, the components and raw materials used in the following examples of the present invention are commercially available.

[0041] Example 1

[0042] Following the above technical solution, Figure 1 As shown, this embodiment provides an air-assisted coaxial electrostatic spray device, including a gas-liquid flow delivery unit, an electrostatic generating device and a receiving plate 4;

[0043] The gas-liquid flow conveying unit includes an outer tube 1 and an inner tube 2 which are coaxially sleeved, and an airflow cavity is formed between the outer tube 1 and the inner tube 2; the inner tube 2 includes a liquid passing pipe 21 and a nozzle 22 which are coaxially connected, and a liquid spraying port is arranged at the front end of the nozzle 22; the rear end of the airflow cavity is closed, and an air outlet is arranged at the front end corresponding to the liquid spraying port; an air inlet is arranged on the side wall of the outer tube 1, and the air inlet is connected to a gas conveying device through a pipeline 3, and the gas conveying device is used to deliver gas into the airflow cavity, and the gas flowing through the airflow cavity can atomize the liquid material flowing out through the nozzle into droplets. In this embodiment, the gas conveying device includes an air compressor or an N2 / Ar gas cylinder; the pipeline 3 is arranged vertically to the outer tube 1.

[0044] The liquid inlet of the liquid passage tube 21 is connected to a syringe, and the syringe is connected to a microinjection pump. The syringe is used to push liquid material into the liquid passage tube 21.

[0045] The electrostatic generating device includes a positive output terminal and a negative output terminal, the positive output terminal is connected to the receiving plate 4, and the negative output terminal is connected to the nozzle 22; the electrostatic generating device can generate a high-voltage electrostatic field between the nozzle 22 and the receiving plate 4; the droplets sprayed by the nozzle 22 can flow from the nozzle 22 to the receiving plate 4 in the high-voltage electrostatic field and form powder at the receiving plate 4.

[0046] In this embodiment, the gas flowing through the airflow cavity is an inert gas, including nitrogen, argon and air. The airflow provides flow-assisting power for the liquid material sprayed through the nozzle 22. At the same time, the high-speed airflow will break up the droplets of the liquid material, increase the specific surface area of ​​the droplets, and increase the evaporation rate of the solvent, thereby realizing the combination of gas phase spraying and electrostatic high-pressure spraying.

[0047] As a preferred solution of this embodiment, the outer tube 1 includes a straight tube portion 11 and a conical portion 12 which are coaxially connected. The distance between the front end face of the conical portion 12 and the front end face of the nozzle 22 is 1 to 3 mm, and the distance between the front end face of the nozzle 22 and the receiving plate 4 is 8 to 15 cm.

[0048] As a preferred solution of this embodiment, the nozzle 22 is in the shape of a truncated cone, the large diameter end of the nozzle 22 is coaxially connected to the liquid passage pipe 21, and the cone angle of the nozzle 22 is smaller than the cone angle of the cone portion 12.

[0049] As a preferred solution of this embodiment, the outer tube 1 is electrically connected to the electrostatic generating device, and the voltage provided by the electrostatic generating device is 16-23 kV.

[0050] As a preferred solution of this embodiment, the outlet pressure of the gas delivery device is 0.1-0.4 MPa.

[0051] When this embodiment is used:

[0052] The precursor dispersion is delivered into the inner tube 2 by means of a syringe, the outlet air pressure of the gas delivery device is set, the gas delivery device is turned on to deliver the gas into the airflow cavity, the electrostatic generating device is turned on to generate a high-voltage electrostatic field, the airflow contacts the precursor dispersion, and under the high-voltage electrostatic action of the high-voltage electrostatic field, a trumpet-shaped liquid jet is formed. After the liquid jet passes a flight distance, as the solvent evaporates, it is finally deposited on the receiving plate to form a composite material powder.

[0053] Example 2

[0054] This embodiment provides a method for preparing an Al / PVDF / Fe2O3 energetic composite material using the gas-assisted coaxial electrostatic spray device disclosed in Example 1, specifically comprising:

[0055] (1) Preparation of Al / PVDF dispersion

[0056] 20 mg of PVDF powder was added to 3 ml of DMF and stirred for 20 min to obtain a PVDF solution; 1 g of aluminum powder (particle size 13 μm) was added to 7 ml of acetone, and after ultrasonic treatment for 10 min, magnetic stirring was performed to obtain an acetone dispersion of micron aluminum powder; the PVDF solution was added to the acetone dispersion of aluminum powder, and Al / PVDF dispersion was obtained by mixing and stirring;

[0057] (2) Preparation of Fe2O3 suspension

[0058] Take 10 mg of Fe2O3 powder and add 10 ml of acetone, disperse it ultrasonically for 30 minutes, and then stir it magnetically to obtain an acetone suspension of Fe2O3.

[0059] (3) Preparation of precursor dispersion

[0060] 10 ml of Al / PVDF suspension was mixed with 10 ml of Fe2O3 suspension and magnetically stirred for 12 h to obtain a precursor dispersion.

[0061] (4) The nozzle is connected to the negative output terminal of the electrostatic generator, and the receiving plate is connected to the positive output terminal of the electrostatic generator. A high-voltage electrostatic field is established between the nozzle and the receiving plate, and the distance between the nozzle and the receiving plate is set to 15-20 cm; the precursor dispersion is sent into the inner tube, the outlet pressure of the gas delivery device is set to 0.2 MPa, and nitrogen is sent into the air flow cavity. The voltage provided by the electrostatic generator is set to 18 kV, so that the droplets sprayed from the nozzle carry electric charge. The droplets flow from the nozzle to the receiving plate in the high-voltage electrostatic field, and finally a dark red powder product is obtained at the receiving plate. The powder on the receiving plate is collected with a wooden spoon for freeze-drying and weighing. The mass of the dark red powder product obtained is 768 mg ( Figure 6 ), yield 74.5%.

[0062] Figure 2 is a SEM image of the Al / PVDF / Fe2O3 energetic composite material prepared in this embodiment; Figure 2 (a) It can be seen that a large amount of powder is deposited on the surface of the aluminum foil on the collecting plate; Figure 2 (b) indicates that the powder is large-sized aluminum powder (average particle size 13 μm); Figure 2 (c) shows that the distribution of Al element is basically consistent with that of Fe element, and there are a large number of spherical particles of Al element distributed, indicating that Al / PVDF / Fe2O3 energetic composite materials have been formed.

[0063] Comparative Example 1

[0064] This embodiment provides a method for preparing Al / PVDF / Fe2O3 energetic composite materials using an existing coaxial electrostatic spray device. The preparation steps and raw material components are the same as those in Example 1. The difference is that the existing coaxial electrostatic spray device only has an electrostatic field directly acting on the droplets, and lacks additional force.

[0065] After the coaxial electrostatic spray preparation was completed, the powder on the receiving plate was collected with a wooden spoon and freeze-dried to obtain the Al / PVDF / Fe2O3 energetic composite material as a dark red powder and weigh it.

[0066] Figure 3 The SEM image of the Al / PVDF / Fe2O3 energetic composite material prepared in this comparative example shows that there are only a few spherical particles on the surface of the aluminum foil on the receiving plate, and the rest of the area is nano-sized Fe2O3. At the same time, the product is only 126 mg ( Figure 6 ), yield 12.2%.

[0067] It can be seen from Example 2 and Comparative Example 1 that in Comparative Example 1, it is difficult to transport the droplets to the sample receiving plate by relying solely on the effect of the electrostatic field, resulting in only large-sized powder particles on the surface of the aluminum foil on the receiving plate, indicating that the coaxial electrostatic spray device used in Comparative Example 1 does not have the ability to further control the powder particle size, and it is difficult to efficiently prepare a large-sized Al / PVDF / Fe2O3 energetic composite material; while Example 2 can efficiently prepare an Al / PVDF / Fe2O3 energetic composite material based on large-sized (13μm) aluminum powder through the dual effects of gas phase assistance and high-voltage electrostatic field. By comparing the data, it can be found that the yield of the method of the present invention is 6.1 times higher than that of the method using only high-voltage electrostatic field.

[0068] Example 3

[0069] This embodiment provides a method for preparing an Al / PVP / MeBH energetic composite material using the gas-assisted coaxial electrostatic spray device disclosed in Example 1, which specifically includes the following steps:

[0070] (1) Preparation of Al / PVP dispersion

[0071] Take 1g of micron aluminum powder and disperse it in 10ml of ethanol, and obtain a micron aluminum powder dispersion by ultrasonic and magnetic stirring; add 40mg of polyvinyl pyrrolidone (PVP) to the micron aluminum powder dispersion; ultrasonic treatment for 10min and magnetic stirring for 20min to obtain an Al / PVP dispersion.

[0072] (2) Preparation of MeBH dispersion

[0073] 200 mg of MeBH was dispersed in 10 ml of ethanol, ultrasonically treated for 10 min, and magnetically stirred for 25 min to obtain an ethanol dispersion of MeBH.

[0074] (3) Preparation of precursor dispersion

[0075] The ethanol dispersion of MeBH was added into the Al / PVP dispersion, and the mixture was stirred for 12 hours to obtain an Al / PVP / MeBH precursor dispersion.

[0076] (4) The nozzle is connected to the negative output end of the electrostatic generator, and the receiving plate is connected to the positive output end of the electrostatic generator. A high-voltage electrostatic field is established between the nozzle and the receiving plate, and the distance between the nozzle and the receiving plate is set to 15-20 cm; the Al / PVP / MeBH precursor dispersion is sent into the inner tube, the outlet pressure of the gas delivery device is set to 0.2 MPa, and nitrogen is sent into the gas flow cavity. The voltage provided by the electrostatic generator is set to 20 kV, so that the droplets sprayed from the nozzle carry electric charge, and the droplets flow from the nozzle to the receiving plate in the high-voltage electrostatic field, and finally a gray powder product is obtained at the receiving plate. The gray powder on the receiving plate is collected with a wooden spoon for freeze-drying and weighing. The mass of the obtained product is 815 mg, and the yield is 65.7%.

[0077] From the SEM image of the Al / PVP / MeBH energetic composite material prepared in this example, it can be seen that a large amount of powder is deposited on the surface of the aluminum foil on the collecting plate. Figure 4 (c) and Figure 4 (d) and EDS element distribution diagram illustrate: there is a large amount of B element in the powder, and Al and B element distribution are closely combined, indicating that Al and MeBH are closely combined through PVP.

[0078] The combustion of the Al / PVP / MeBH energetic composite material prepared in this example was monitored at the propellant combustion surface. The results are as follows: Figure 6 As shown, from Figure 6 The splitting process of two molten aluminum balls can be seen in the figure, indicating that the presence of MeBH can effectively inhibit the melting and agglomeration process of Al.

[0079] Comparative Example 2

[0080] This embodiment provides a method for preparing an Al / PVP / MeBH energetic composite material using an existing coaxial electrostatic spray device. The preparation steps and raw material components are the same as those in Example 3, except that the existing coaxial electrostatic spray device only has an electrostatic field directly acting on the droplets, lacks additional force, and is difficult to transport the droplets to the sample receiving plate. After the coaxial electrostatic spray preparation is completed, the powder on the receiving plate is collected with a wooden spoon and freeze-dried to obtain a gray powder product and weigh it. The product mass is 65 mg and the yield is 5.2%.

[0081] Figure 5 The SEM image of the Al / PVP / MeBH energetic composite material obtained in this comparative example shows that a large amount of powder is deposited on the surface of the aluminum foil on the receiving plate, but there is only a very small amount of white powder. Upon testing, most of the product is MeBH / PVP, with only a few Al / PVP / MeBH particles.

[0082] It can be seen from Example 3 and Comparative Example 2 that it is difficult to efficiently prepare large-sized Al / PVP / MeBH energetic composite materials relying solely on the action of an electrostatic field; through the dual action of gas phase assistance and a high-voltage electrostatic field, an Al / PVP / MeBH energetic composite material based on large-sized (13 μm) aluminum powder can be efficiently prepared; the yield of the method of the present invention is 12.6 times higher than that of the existing coaxial electrostatic spray method using only a high-voltage electrostatic field.

[0083] In summary, the air-assisted coaxial electrostatic spray device provided by the present invention forms an airflow cavity between the outer tube and the inner tube through a coaxially sleeved outer tube. The airflow enters the airflow cavity through a pipe perpendicular to the outer tube, and contacts with the precursor dispersion at the air outlet, forming a trumpet-shaped liquid jet under the action of a high-voltage electrostatic field. After the liquid jet flies a distance, as the solvent evaporates, it is finally deposited at the receiving plate to form an aluminum-based energetic composite material powder composed of micron-scale aluminum powder. The preparation of large-size aluminum-based energetic composite materials is achieved through a gas-assisted approach, and the preparation efficiency of the energetic composite materials is greatly improved.

[0084] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0085] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An air-assisted coaxial electrostatic spray device, characterized in that: It comprises a gas-liquid flow conveying unit, a static electricity generating device and a receiving plate (4); The gas-liquid flow conveying unit comprises a coaxially sleeved metal outer tube (1) and an inner tube (2), wherein an air flow cavity is formed between the outer tube (1) and the inner tube (2); the inner tube (2) comprises a liquid passing tube (21) and a nozzle (22) which are coaxially connected and arranged, and a liquid spraying port is arranged at the front end of the nozzle (22); the rear end of the air flow cavity is closed, and an air outlet is arranged at the front end corresponding to the liquid spraying port; an air inlet is arranged on the side wall of the outer tube (1), and the air inlet is connected to a gas conveying device via a pipeline (3), and the gas conveying device is used to deliver gas into the air flow cavity; The electrostatic generating device comprises a positive output terminal and a negative output terminal, the positive output terminal is connected to the receiving plate (4), and the negative output terminal is connected to the nozzle (22); the electrostatic generating device can generate a high-voltage electrostatic field between the nozzle (22) and the receiving plate (4); the droplets sprayed by the nozzle (22) can flow from the nozzle (22) to the receiving plate (4) in the high-voltage electrostatic field and form powder at the receiving plate (4).

2. The air-assisted coaxial electrostatic spray device according to claim 1, characterized in that: The outer tube (1) comprises a straight tube portion (11) and a conical portion (12) which are coaxially connected, the distance between the front end face of the conical portion (12) and the front end face of the nozzle (22) is 1 to 3 mm, and the distance between the front end face of the nozzle (22) and the receiving plate (4) is 8 to 15 cm.

3. The air-assisted coaxial electrostatic spray device according to claim 2, characterized in that: The nozzle (22) is in the shape of a truncated cone, the large diameter end of the nozzle (22) is coaxially connected to the liquid passage pipe (21), and the cone angle of the nozzle (22) is smaller than the cone angle of the conical portion (12).

4. The air-assisted coaxial electrostatic spray device according to claim 1, characterized in that: The outer tube (1) is electrically connected to the static electricity generating device.

5. The air-assisted coaxial electrostatic spray device according to claim 1, characterized in that: The outlet pressure of the gas delivery device is 0.1-0.4 MPa.

6. A method for preparing an aluminum-based energetic composite material using the air-assisted coaxial electrostatic spray device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1, adding adhesive powder to a first organic solvent and stirring evenly to obtain an adhesive solution; adding micron aluminum powder to a second organic solvent, and subjecting the mixture to ultrasonic and magnetic stirring treatment to obtain a micron aluminum powder dispersion; Adding the binder solution into the micron aluminum powder dispersion, mixing and stirring to obtain the micron aluminum powder / binder dispersion; Step 2, adding the powders of other components into a third organic solvent, and subjecting the mixture to ultrasonic and magnetic stirring treatment to obtain a dispersion of other components; Step 3, mixing the other component dispersions obtained in step 2 with the micron aluminum powder dispersion obtained in step 1 to obtain a precursor dispersion; Step 4: The nozzle is connected to the negative output terminal of the electrostatic generator, and the receiving plate is connected to the positive output terminal of the electrostatic generator, so as to establish a high-voltage electrostatic field between the nozzle and the receiving plate; the electrostatic spray parameters are set, the precursor dispersion is sent into the inner tube, and the gas is sent into the air flow cavity, and the droplets sprayed from the nozzle form an aluminum-based energetic composite material at the receiving plate; The precursor solution comprises the following raw material components by mass percentage: 5-10% of micron aluminum powder, 1-3% of a binder, and 87-94% of other components.

7. The method according to claim 6, characterized in that The particle size of the micron aluminum powder is 1 μm to 40 μm, and the gas includes nitrogen, argon and air.

8. The method according to claim 6, characterized in that The adhesive is selected from one of PVDF and PVP; the first organic solvent is selected from one of DMF, methanol, ethanol and tetrahydrofuran, the second organic solvent and the third organic solvent are selected from one or both of acetone and ethanol; the other components are selected from one of Fe2O3 and MeBH.

9. The method according to claim 6, characterized in that In step 1, the ultrasonic treatment time is 5 to 20 minutes; in step 2, the ultrasonic treatment time is 20 to 30 minutes.

10. The method according to claim 6, characterized in that The electrostatic spray parameters described in step 4 include: the voltage provided by the electrostatic generating device is 16 to 23 kV, the receiving distance between the receiving plate and the nozzle is 8 to 15 cm, and the outlet gas pressure of the gas conveying device is 0.2 to 0.4 MPa.

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