Quaternary energetic material with core-shell structure as well as preparation method and application of quaternary energetic material

Abstract

The invention provides a quaternary energetic material with a core-shell structure as well as a preparation method and application thereof, and the preparation method comprises the following specific steps: S1, sequentially dissolving nano magnesium powder and potassium nitrate powder in an organic solvent, and heating and stirring to obtain Mg / KNO3 energetic slurry; s2, nano aluminum powder and PTFE powder are subjected to ultrasonic treatment to obtain metastable-state mixed powder, then the metastable-state mixed powder is added into the prepared polymer binder, and Al / PTFE metastable-state composite slurry is obtained through heating, stirring and evaporation treatment; and S3, respectively adding the Mg / KNO3 energetic slurry obtained in the S1 and the Al / PTFE metastable composite slurry obtained in the S2 into two different charging barrels of a 3D printer, adjusting equipment parameters of the 3D printer, and processing to obtain the Al / PTFE / Mg / KNO3 quaternary energetic material with the core-shell structure. According to the quaternary energetic material, the ignition temperature of an existing composite system material can be reduced, meanwhile, carbon residues formed after combustion are further reduced, meanwhile, the processing technology is simple, and the personalized forming requirement can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of energetic materials, and relates to a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material based on additive manufacturing technology, and a preparation method and application thereof. Background Art

[0002] As a special energetic material, Al / PTFE (aluminum / polytetrafluoroethylene) metastable composite materials have attracted widespread attention due to their high reaction energy release, relative stability and safety. However, among the existing problems of the Al / PTFE system, one is that there is a large amount of residue left after the reaction, and there is a lack of oxygen-containing substances to be converted into gas to increase the gas production of the system; the second is that the initial reaction temperature of the system reaches 400°C, and the main reaction is nearly 500°C. Such a high reaction threshold makes it not outstanding in practical applications, so that the system is rarely used in the production and manufacturing of actual products. In addition, in the field of energetic materials such as explosives, there is still the problem of difficulty in the molding and processing of energetic materials. Based on the different carrying equipment and space, its finalization processing technology has more refined and personalized customization requirements. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material based on additive manufacturing technology, and a preparation method and application thereof. On the basis of the traditional Al / PTFE system, the Mg / KNO3 (magnesium / potassium nitrate) system is introduced to reduce the overall reaction temperature of the energetic material and reduce the remaining combustion residue. At the same time, additive manufacturing technology (also known as 3D printing technology) is used in conjunction with a special processing and molding process to generate a core-shell structured quaternary energetic material to ensure further optimization of the combustion performance of the energetic material and meet personalized customization requirements.

[0004] To achieve the above-mentioned effects, the first aspect of the present invention provides a method for preparing a core-shell structured quaternary energetic material, which is characterized in that it comprises the following specific steps: S1: dissolving nano-magnesium powder and potassium nitrate powder in an organic solvent in turn, and obtaining Mg / KNO3 energetic slurry through heating and stirring; S2: ultrasonically treating nano-aluminum powder and PTFE powder to obtain a metastable mixed powder, and then adding the metastable mixed powder to a prepared polymer binder, and obtaining Al / PTFE metastable composite slurry through heating, stirring and evaporation; S3: adding the Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 to two different barrels of a 3D printer, adjusting the equipment parameters of the 3D printer, and respectively collecting them through two passages into a nozzle with a dual-channel barrier effect, and obtaining the core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material through extrusion molding.

[0005] Optionally, S1 specifically includes: S11: dissolving nano magnesium powder in a sufficient amount of glycerol, heating and stirring until fully dissolved, and then cooling to room temperature to obtain a concentrated magnesium metal solution; S12: dissolving potassium nitrate powder in a sufficient amount of glycerol, and stirring sufficiently to obtain a nitro solution; S13: adding the concentrated magnesium metal solution prepared in S11 to the nitro solution prepared in S12 in batches, gradually volatilizing the glycerol solvent by heating and stirring to control the overall viscosity of the mixed solution, and obtaining a Mg / KNO3 energetic slurry.

[0006] Optionally, the particle size of the nano magnesium powder in S11 is 100 nm, the heating temperature is 40-50° C., and the stirring rate is 30-45 r / min; the heating in S13 is to increase the temperature from room temperature to 40° C. at a rate of 1.6° C. / min, and the stirring rate is 40 r / min.

[0007] Optionally, S2 specifically includes: S21: fully dissolving fluororubber in ethyl acetate to obtain a polymer adhesive; S22: blending nano aluminum powder with PTFE powder, and obtaining a metastable mixed powder after ultrasonic treatment; S23: adding the polymer adhesive obtained in S21 and the metastable mixed powder obtained in S22 to a sufficient amount of ethyl acetate to fully dissolve, and obtaining an Al / PTFE metastable composite slurry with adjusted viscosity after mechanical stirring and heating for evaporation.

[0008] Optionally, the fluororubber described in S21 is fluororubber F2311, and the mass of the ethyl acetate is 5 times that of the fluororubber; the particle size of the nano aluminum powder described in S22 is 50nm, and the time of the ultrasonic treatment is 3-5 hours; the rate of mechanical stirring described in S23 is 40-60r / min, and the cut-off temperature of the heating evaporation is 60-80°C.

[0009] Optionally, the nozzle in S3 is constructed as follows: when 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed in the outer layer of the energetic material after molding to form a shell structure; and the Al / PTFE metastable composite slurry energetic slurry obtained in S2 is placed in the inner layer of the energetic material after molding to form a core structure.

[0010] Optionally, the shell structure and the core structure are extruded separately through the dual channels of the nozzle; wherein the Mg / KNO3 energetic slurry is extruded through the outer channel of the nozzle to form a shell structure; and the Al / PTFE metastable composite energetic slurry is extruded through the inner channel arranged in the middle of the outer channel to form a core structure.

[0011] Optionally, the equipment parameters in S3 include: the feeding speed of the outer layer energetic slurry is 15-30 mm / s, and the feeding speed of the inner layer energetic slurry is 9-18 mm / s; the nozzle material is stainless steel, and the dual channels of the nozzle are blocked by a blocking member built into the nozzle or detachably arranged on the nozzle.

[0012] The second aspect of the present invention provides a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material prepared according to the preparation method.

[0013] The third aspect of the present invention provides an application of the Al / PTFE / Mg / KNO3 quaternary energetic material according to the core-shell structure in the field of energetic materials.

[0014] The beneficial effects of the present invention are:

[0015] (1) Mg / KNO3 can produce N2, O2 and other gases during the reaction. The generated oxygen can react with the carbon residue of Al / PTFE to generate products such as CO. By introducing Mg / KNO3 into the original system, the gas production and reaction heat of the system are increased, the residue after the reaction is reduced, and the defects and deficiencies of Al / PTFE are effectively improved, which significantly improves the performance of the entire energetic material system.

[0016] (2) The constructed core-shell structure realizes hierarchical and staged combustion control. Mg / KNO3 has a low reaction temperature. As the outer layer material of the energetic material, it reacts first when ignited and generates a large amount of heat, which can conduct the heat flow to the inner layer Al / PTFE system. The chemical energy released inside it further reduces the reaction threshold, allowing the system to use lower external conditions to stimulate the reaction of the entire system.

[0017] (3) The use of additive manufacturing technology provides a reasonable and feasible process for the formation of the core-shell structure. By constructing two independent feeding passages, the two slurries can be processed into an inner and outer double-layer structure. The preparation process is simple and easy to operate, making industrial mass production possible.

[0018] Therefore, the core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material based on additive manufacturing technology has potential application prospects in the field of energetic materials.

[0019] In addition, additional advantages, objects, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The objects and other advantages of the present invention may be realized and obtained by the structures and methods specifically pointed out in the written description and claims and the accompanying drawings.

[0020] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention.

[0022] Figure 1 It is a schematic flow chart of a method for preparing a quaternary energetic material with a core-shell structure according to an embodiment of the present invention;

[0023] Figure 2 This is a SEM-Mapping test diagram of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure in an embodiment of the present invention;

[0024] Figure 3 This is a test diagram of the limiting oxygen index of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure in an embodiment of the present invention;

[0025] Figure 4 The internal ballistic performance test results of the Al / PTFE / Mg / KNO3 quaternary energetic material with core-shell structure in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should also be noted that, in order to avoid blurring the present invention due to unnecessary details, only structures and / or processes closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0027] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, or components, but does not exclude the presence or addition of one or more other features, elements, or components.

[0028] Combination Figure 1It can be seen that the first aspect of the embodiment of the present invention is a method for preparing a core-shell structured quaternary energetic material, which is characterized by comprising the following specific steps: S1: dissolving nano-magnesium powder and potassium nitrate powder in an organic solvent in turn, and obtaining Mg / KNO3 energetic slurry through heating and stirring; S2: ultrasonically treating nano-aluminum powder and PTFE powder to obtain a metastable mixed powder, and then adding the metastable mixed powder to a prepared polymer binder, and obtaining Al / PTFE metastable composite slurry through heating, stirring and evaporation; S3: adding the Mg / KNO3 energetic slurry obtained by S1 and the Al / PTFE metastable composite slurry obtained by S2 to two different barrels of a 3D printer, adjusting the 3D printer equipment parameters, and respectively converging them into a nozzle with a dual-channel barrier effect through two passages, and obtaining the core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material through extrusion molding.

[0029] Optionally, S1 specifically includes: S11: dissolving nano magnesium powder in a sufficient amount of glycerol, heating and stirring until fully dissolved, and then cooling to room temperature to obtain a concentrated magnesium metal solution; S12: dissolving potassium nitrate powder in a sufficient amount of glycerol, and stirring sufficiently to obtain a nitro solution; S13: adding the concentrated magnesium metal solution prepared in S11 to the nitro solution prepared in S12 in batches, gradually volatilizing the glycerol solvent by heating and stirring to control the overall viscosity of the mixed solution, and obtaining a Mg / KNO3 energetic slurry. Among them, potassium nitrate, as a strong oxidizing substance, can produce various chemical reactions to produce a series of gases such as nitrogen and oxygen; while nano-metal magnesium powder can react with PTFE on the one hand, and can also react with KNO3 to produce gas on the other hand, and the reaction temperature of these two reactions is relatively low. It can be used as an initiator of the entire system through its own low reaction conditions, and use itself to generate a large amount of heat to cause the Al / PTFE system to activate and release energy secondary. On the one hand, the demand for initial external conditions is reduced, that is, the reaction can be started without providing harsh temperature conditions at the beginning, and on the other hand, the gas production of the system is increased at the same time, which provides a path exploration for the application of aluminum-based metastable energetic materials in the field.

[0030] Optionally, in S11, the particle size of the nano magnesium powder is 100 nm, the heating temperature is 40-50° C., and the stirring rate is 30-45 r / min; in S13, the heating is to increase the temperature from room temperature to 40° C. at a rate of 1.6° C. / min, and the stirring rate is 40 r / min.

[0031] Optionally, S2 specifically includes: S21: fully dissolving fluororubber in ethyl acetate to obtain a polymer adhesive; S22: blending nano aluminum powder with PTFE powder, and obtaining a metastable mixed powder after ultrasonic treatment; S23: adding the polymer adhesive obtained in S21 and the metastable mixed powder obtained in S22 to a sufficient amount of ethyl acetate to fully dissolve, and obtaining an Al / PTFE metastable composite slurry with adjusted viscosity after mechanical stirring and heating for evaporation.

[0032] Optionally, the fluororubber in S21 is fluororubber F2311, and the mass of ethyl acetate is 5 times that of fluororubber; the particle size of the nano aluminum powder in S22 is 50nm, and the ultrasonic treatment time is 3-5 hours; the mechanical stirring rate in S23 is 40-60r / min, and the heating evaporation cut-off temperature is 60-80°C. The reason for using fluororubber F2311 is that it has a strong intermolecular force with PTFE and Al powder, and has a better bonding effect.

[0033] Optionally, the nozzle in S3 is constructed as follows: when 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed in the outer layer of the energetic material after molding to form a shell structure; and the Al / PTFE metastable composite slurry energetic slurry obtained in S2 is placed in the inner layer of the energetic material after molding to form a core structure. Additive manufacturing technology has now been widely used in various fields. As a new molding processing method, it has also attracted attention in the field of energetic materials, making the above-mentioned molding process of separately processing the inner and outer layers possible, solving the problem of difficult molding processing of explosive raw materials.

[0034] Optionally, the shell structure and the core structure are extruded separately through the dual channels of the nozzle; wherein the Mg / KNO3 energetic slurry is extruded through the outer channel of the nozzle to form a shell structure; and the Al / PTFE metastable composite energetic slurry is extruded through the inner channel arranged in the middle of the outer channel to form a core structure.

[0035] Optionally, the equipment parameters described in S3 include: the feeding speed of the outer layer energetic slurry is 15-30mm / s, and the feeding speed of the inner layer energetic slurry is 9-18mm / s; the nozzle material is stainless steel, and the dual channels of the nozzle are blocked by a barrier built into the nozzle or detachably set on the nozzle. Through the design and transformation of the equipment, the raw materials are processed into a more refined sample structure with customized requirements, making full use of the advantages and characteristics of additive manufacturing technology.

[0036] The second aspect of the present invention provides a core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material prepared according to the preparation method. Figure 2Shown is the SEM-Mapping test image of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure in this embodiment.

[0037] like Figure 3 This is a test diagram of the limiting oxygen index of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure in the embodiment of the present invention. It can be seen that the limiting oxygen index of the material sample prepared by the embodiment method is determined by a three-step method. The results show that its limiting oxygen index is 34.1%. The reason is that the ignition temperature in the experiment has not yet reached the initial reaction temperature of the thermite reaction. Oxygen and the decomposition products of KNO3 play a role in supporting combustion. They first react with metal powder to release a large amount of heat, and the temperature rises to meet the conditions for thermite reaction, and then a violent reaction occurs. The report shows that when the conditions are met, the sample is quickly ashed and the reaction is completed in a short time. On the one hand, this result can explain the combustibility of the sample to a certain extent; on the other hand, it proves that its safety is guaranteed. First, the temperature needs to meet the reaction conditions, and second, it plays a combustion-supporting effect and ignites when the oxygen concentration reaches 34%. For storage at room temperature, both are not met, and theoretically it has good stability and storage performance.

[0038] like Figure 4 The internal ballistic performance test results of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure in this embodiment. It can be seen intuitively from the figure that compared with the binary components of Al / PTFE and Mg / PTFE, the quaternary Al / PTFE / Mg / KNO3 material has a higher combustion speed and explosion pressure, and can produce more gas products, proving its feasibility as a new type of active energetic material.

[0039] The third aspect of the present invention provides an application of a quaternary energetic material of Al / PTFE / Mg / KNO3 with a core-shell structure in the field of energetic materials.

[0040] The present invention will be further described in detail below through specific implementation examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0041] Example 1

[0042] First, prepare Mg / KNO3 energetic slurry. Dissolve 1 part of Mg metal powder with a particle size of 100 nm in sufficient glycerol, heat to 40°C, stir thoroughly at a rate of 30 r / min, cool and store at room temperature at 25°C to obtain a metal concentrated solution. Dissolve 2 parts of KNO3 in glycerol and stir thoroughly to obtain a nitro solution. Slowly add the prepared metal concentrated solution to the nitro solution obtained in S12 in batches, then slowly increase the temperature from room temperature to 40°C at a rate of 1.6°C / min, stir thoroughly at a rate of 40 r / min, gradually volatilize the glycerol part of the system by temperature to control its viscosity, and obtain Mg / KNO3 energetic slurry.

[0043] Secondly, Al / PTFE metastable composite slurry is prepared. One portion of fluororubber F2311 is fully dissolved in ethyl acetate which is five times its own mass to obtain a polymer adhesive. Aluminum metal powder with a particle size of 50 nm is blended with PTFE polymer powder, and a metastable mixed powder is obtained after ultrasonic homogenization treatment for 3 hours. The prepared polymer adhesive and metastable mixed powder are added to a sufficient amount of ethyl acetate organic solvent to be fully mixed and dissolved. After mechanical stirring at a rate of 40 r / min, the solvent is heated to 60°C to evaporate and the viscosity is controlled to obtain Al / PTFE metastable composite slurry.

[0044] Finally, the obtained Mg / KNO3 energetic slurry and Al / PTFE metastable composite slurry were added into the two barrels of the 3D printer respectively, and finally converged into a special nozzle with a double-layer barrier effect through two passages. The 3D printer parameters were controlled as the outer layer printing speed of 15 mm / s and the inner layer printing speed of 9 mm / s. After extrusion molding, the core-shell structured Al / Mg / PTFE / KNO3 quaternary energetic material based on additive manufacturing technology was obtained.

[0045] Example 2

[0046] First, Mg / KNO3 energetic slurry is prepared. One part of Mg metal powder with a particle size of 100 nm is dissolved in sufficient glycerol, heated to 45°C, stirred at a rate of 40 r / min, cooled and stored at room temperature of 25°C to obtain a metal concentrated solution, and two parts of KNO3 are dissolved in glycerol and stirred to obtain a nitro solution. The prepared metal concentrated solution is slowly added to the nitro solution obtained in S12 in batches, and then the temperature is slowly raised from room temperature to 40°C at a rate of 1.6°C / min, and stirred evenly at a rate of 40 r / min. The glycerol part of the system is gradually volatilized by temperature to control its viscosity, and Mg / KNO3 energetic slurry is obtained.

[0047] Secondly, Al / PTFE metastable composite slurry is prepared. One portion of fluororubber F2311 is fully dissolved in ethyl acetate which is five times its own mass to obtain a polymer adhesive. Aluminum metal powder with a particle size of 50 nm is blended with PTFE polymer powder, and a metastable mixed powder is obtained after ultrasonic homogenization treatment for 4 hours. The prepared polymer adhesive and metastable mixed powder are added into a sufficient amount of ethyl acetate organic solvent to be fully mixed and dissolved. After mechanical stirring at a rate of 50 r / min, the solvent is evaporated and then the viscosity is controlled to obtain Al / PTFE metastable composite slurry.

[0048] Finally, the obtained quaternary energetic precursors were added into the two barrels of the 3D printer respectively, and finally converged into a special nozzle with a double-layer barrier effect through two passages. The 3D printer parameters were controlled as the outer layer printing speed of 20 mm / s and the inner layer printing speed of 12 mm / s. After extrusion molding, the core-shell structured Al / Mg / PTFE / KNO3 quaternary energetic material based on additive manufacturing technology was obtained.

[0049] Example 3

[0050] First, prepare Mg / KNO3 energetic slurry. Dissolve 1 part of Mg metal powder with a particle size of 100nm in sufficient glycerol, heat to 50℃, stir thoroughly at a rate of 45r / min, cool and store at room temperature of 25℃ to obtain a metal concentrated solution. Dissolve 2 parts of KNO3 in glycerol and stir thoroughly to obtain a nitro solution. Slowly add the prepared metal concentrated solution to the nitro solution obtained in S12 in batches, then slowly increase the temperature from room temperature to 40℃ at a rate of 1.6℃ / min, stir thoroughly at a rate of 40r / min, gradually volatilize the glycerol part of the system by temperature to control its viscosity, and obtain Mg / KNO3 energetic slurry.

[0051] Secondly, Al / PTFE metastable composite slurry is prepared. One portion of fluororubber F2311 is fully dissolved in ethyl acetate which is five times its own mass to obtain a polymer adhesive. Aluminum metal powder with a particle size of 50 nm is blended with PTFE polymer powder, and a metastable mixed powder is obtained after ultrasonic homogenization treatment for 5 hours. The prepared polymer adhesive and metastable mixed powder are added into a sufficient amount of ethyl acetate organic solvent to be fully mixed and dissolved. After mechanical stirring at a rate of 60 r / min, the Al / PTFE metastable composite slurry is obtained after heating to 80°C to evaporate the solvent.

[0052] Finally, the obtained quaternary energetic precursors were added into the two barrels of the 3D printer respectively, and finally converged into a special nozzle with a double-layer barrier effect through two passages. The 3D printer parameters were controlled as the outer layer printing speed of 30 mm / s and the inner layer printing speed of 18 mm / s. After extrusion molding, the core-shell structured Al / Mg / PTFE / KNO3 quaternary energetic material based on additive manufacturing technology was obtained.

[0053] Comparative Example

[0054] The Al / PTFE binary energetic material is prepared using the traditional sintering process. The two powders with a mass ratio of 3:7 are blended at room temperature and then pressed. They are then sintered at a temperature of about 300°C, molded, and cooled to obtain a sintered Al / PTFE mixed energetic charge. However, one of the disadvantages of the traditional processing technology is that the shape of the mold is limited, and it is impossible to process more sophisticated and complex structures, such as core-shell structures, and the processing equipment is large and the cost is high.

[0055] Table 1: Performance test comparison table of the core-shell structure Al / Mg / PTFE / KNO3 quaternary energetic materials of the present invention

[0056]

[0057]

[0058] As can be seen from Table 1, the above Example 3 is a preferred solution. After the introduction of KNO3 and Mg powder into Al / PTFE, the energy release is improved, the reaction residues are reduced, and the initial threshold of the reaction is lowered. This shows that the gas produced by the decomposition of KNO3 can further react with the residues of the original system for a secondary reaction, thereby improving the reaction energy release and realizing the efficient utilization of energy to the greatest extent; the addition of Mg powder reduces the initial threshold of the chemical reaction, and the pre-ignition reaction can be carried out under lower conditions.

[0059] In addition, the core-shell structured Al / Mg / PTFE / KNO3 quaternary energetic material prepared by the present invention meets the requirements of new active energetic materials, and has the characteristics of low cost, easy production, high energy, and stable performance at room temperature.

[0060] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0061] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0062] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a core-shell structured quaternary energetic material, characterized in that: The specific steps include: S1: dissolving nano magnesium powder and potassium nitrate powder in an organic solvent successively, and obtaining Mg / KNO3 energetic slurry by heating and stirring; S2: subjecting nano-aluminum powder and PTFE powder to ultrasonic treatment to obtain a metastable mixed powder, and then adding the metastable mixed powder to the prepared polymer binder, and subjecting the mixture to heating, stirring and evaporation treatment to obtain an Al / PTFE metastable composite slurry; S3: The Mg / KNO3 energetic slurry obtained in S1 and the Al / PTFE metastable composite slurry obtained in S2 are added into two different barrels of the 3D printer respectively, and the equipment parameters of the 3D printer are adjusted. The slurries are respectively collected into a nozzle with a dual-channel barrier effect through two passages, and the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure is obtained by extrusion molding.

2. The preparation method according to claim 1, characterized in that: S1 specifically includes: S11: dissolving nano magnesium powder in a sufficient amount of glycerol, heating and stirring until fully dissolved, and then cooling to room temperature to obtain a concentrated magnesium metal solution; S12: dissolving potassium nitrate powder in sufficient amount of glycerol and stirring thoroughly to obtain a nitro solution; S13: The magnesium metal concentrated solution prepared in S11 is added in batches to the nitro solution prepared in S12, and the glycerol solvent is gradually volatilized by heating and stirring to control the overall viscosity of the mixed solution to obtain Mg / KNO3 energetic slurry.

3. The preparation method according to claim 2, characterized in that: The particle size of the nano magnesium powder in S11 is 100 nm, the heating temperature is 40-50° C., and the stirring rate is 30-45 r / min; The heating in S13 is to increase the temperature from room temperature to 40° C. at a rate of 1.6° C. / min, and the stirring rate is 40 r / min.

4. The preparation method according to claim 1, characterized in that: S2 specifically includes: S21: fully dissolving fluororubber in ethyl acetate to obtain a polymer adhesive; S22: blending nano-aluminum powder and PTFE powder, and obtaining a metastable mixed powder after ultrasonic treatment; S23: adding the polymer binder obtained in S21 and the metastable mixed powder obtained in S22 into a sufficient amount of ethyl acetate to fully dissolve them, and then mechanically stirring and heating to evaporate them to obtain an Al / PTFE metastable composite slurry with adjusted viscosity.

5. The preparation method according to claim 4, characterized in that: The fluororubber in S21 is fluororubber F2311, and the mass of the ethyl acetate is 5 times that of the fluororubber; The particle size of the nano aluminum powder in S22 is 50 nm, and the ultrasonic treatment time is 3-5 hours; The mechanical stirring rate in S23 is 40-60 r / min, and the cut-off temperature of the heating evaporation is 60-80°C.

6. The preparation method according to claim 1, characterized in that: The nozzle in S3 is constructed as follows: When 3D printing is performed, the Mg / KNO3 energetic slurry obtained in S1 is placed on the outer layer of the molded energetic material to form a shell structure; Furthermore, the Al / PTFE metastable composite energetic slurry obtained in S2 is placed in the inner layer of the molded energetic material to form a core structure.

7. The preparation method according to claim 6, characterized in that: The shell structure and the core structure are extruded separately through the double channels of the nozzle; Wherein, the Mg / KNO3 energetic slurry is extruded through the outer channel of the nozzle to form a shell structure; Furthermore, the Al / PTFE metastable composite energetic slurry is extruded through an inner layer channel arranged in the middle of the outer layer channel to form a core structure.

8. The preparation method according to claim 6, characterized in that: The device parameters described in S3 include: The feeding speed of the outer layer energetic slurry is 15-30 mm / s, and the feeding speed of the inner layer energetic slurry is 9-18 mm / s; The nozzle is made of stainless steel, and the dual channels of the nozzle are blocked by a blocking member that is built into the nozzle and / or detachably disposed on the nozzle.

9. A core-shell structured Al / PTFE / Mg / KNO3 quaternary energetic material prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the Al / PTFE / Mg / KNO3 quaternary energetic material with a core-shell structure according to claim 9 in the field of energetic materials.

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