DAP-4-containing high-energy low-sensitivity superfine composite oxidant and preparation method thereof

Abstract

The invention provides a DAP-4-containing high-energy low-sensitivity superfine composite oxidizing agent and a preparation method of the DAP-4-containing high-energy low-sensitivity superfine composite oxidizing agent. Comprising a DAP-4 / AP composite oxidant and a DAP-4 / AN composite oxidant. The invention also relates to a preparation method of the high-energy low-sensitivity superfine composite oxidant containing DAP-4. According to the invention, after the sensibility reducing agent is added and is coated or doped in the superfine DAP-4 / AP or DAP-4 / AN composite oxidizing agent particles, the friction force among the superfine oxidizing agent particles is greatly reduced, and the particles are very smooth, so that the friction sensitivity of DAP-4 is greatly reduced, and the DAP-4-containing composite oxidizing agent with the characteristic of low sensitivity is obtained; the DAP-4-containing composite oxidizing agent prepared by the method has the characteristic of good dispersity; the raw materials involved in the method are easy to obtain, low in cost, free of by-products and environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the field of pyrotechnic explosives; in particular, it relates to a DAP-4 high-energy and low-sensitivity ultrafine composite oxidizer and a preparation method thereof. Background Art

[0002] DAP-4 is a new type of molecular perovskite energetic material, first designed and synthesized by Academician Chen Xiaoming of Sun Yat-sen University in 2018 (Shao-Li Chen, Zi-Run Yang, Bin-Jie Wang, et al. Molecular perovskite high-energetic materials[J]. Science China Materials, 2018, 61(8): 1123-1128.). DAP-4 has an ABX 3 structure, where A is a protonated triethylenediamine cation (H 2 dabco 2+ , that is, C 6 H 14 N 2 2+ ), B is an NH 4 + cation, and X is a ClO 4 - anion. That is, the chemical formula of DAP-4 is: (H 2 dabco)[NH 4 (ClO 4 ) 3 . This energetic material with an ABX 3 structure is different from traditional pyrotechnic propellants. It cleverly combines the commonly used fuel (H 2 dabco 2+ ) and oxidizer (ClO 4 - ) in a crystal structure, creating optimal conditions for the redox reaction between them. At present, a variety of molecular perovskite energetic materials with this structure have been prepared, and only DAP-4 has practical value.

[0003] The molecular weight of DAP-4 is 430.6 g / mol, the density is 1.87 g / cm 3 , and the oxygen balance is OB CO =-5.6%, OB CO2= -27.9%, the enthalpy of formation is +278.6 kJ / mol, and the theoretical detonation velocity reaches 8597 m / s (close to RDX). The theoretical detonation heat and detonation pressure of DAP-4 are -6879 kJ / kg and 35.6 GPa, which are relatively high among the known single-component explosives. At the same time, DAP-4 is also an excellent heat-resistant energetic material, with an initial thermal decomposition temperature of 374 °C and a decomposition peak temperature of 401 °C (10 °C / min). In addition, although DAP-4 is an ionic salt, it has the characteristic of not being hygroscopic. Moreover, DAP-4 has good chemical compatibility with the commonly used components in composite explosives and propellants. Therefore, from the perspective of solid propellants, DAP-4 is an extremely excellent high-energy filler because its specific impulse of the unit propellant is as high as I sp = 289 s (calculated by NASA-CEA2, P c = 7 MPa, P e = 1 MPa, T 0 = 298 K, ΔH f,DAP-4 = +278.6 kJ / mol). For the CMDB propellant modified with it, the specific impulse can even reach I sp = 277.9 s (NC 20％ / NG 20％ / Al 5％ / DAP-4 55％ ). This is a great progress for solid propellants because for the CMDB propellant modified with hexanitrohexaazaisowurtzitane (CL-20) (NC 20％ / NG 20％ / Al 5％ / CL-20 55％ ), the specific impulse is only I sp = 268.4 s. This shows that once DAP-4 is successfully applied in solid propellants, the range of rockets and missiles will increase by 25 - 35%.

[0004] However, there is an important problem in the application of DAP-4 in propellants, that is, the friction sensitivity of DAP-4 is too high, and the speed of combustion to detonation is too fast. In fact, the impact sensitivity and electrostatic sensitivity of DAP-4 are not high. Its impact sensitivity is H 50= 112.3 cm (2 kg drop hammer), the electrostatic sensitivity is 5.39 J, and these two data are close to those of trinitrotoluene (TNT). TNT is an extremely insensitive explosive. However, due to crystal structure problems, the friction sensitivity of DAP-4 is much higher than that of TNT, even higher than that of pentaerythritol tetranitrate (PETN) and hexanitrohexaazaisowurtzitane (CL-20); moreover, even in a loose powder state, once the thermal decomposition of DAP-4 is triggered, it will transform into detonation at an extremely fast speed, rather than combustion. While PETN and CL-20 hardly detonate in a loose state and mainly decompose by combustion. And whether it is double-base series propellants or composite propellants, there are strong friction processes during the preparation, which makes the addition of DAP-4 extremely dangerous.

[0005] However, how to mix DAP-4 with the traditional oxidizers ammonium perchlorate (AP) or ammonium nitrate (AN) of propellants to finally obtain a very stable substance has not been reported. Summary of the Invention

[0006] The object of the present invention is to provide a high-energy and low-sensitivity ultrafine composite oxidizer containing DAP-4 and its preparation method.

[0007] The present invention is achieved by the following technical solutions:

[0008] The present invention relates to a high-energy and low-sensitivity ultrafine composite oxidizer containing DAP-4, including DAP-4 / AP composite oxidizer and DAP-4 / AN composite oxidizer;

[0009] The DAP-4 / AP composite oxidizer includes the following components in the following amounts:

[0010] 25 g of coarse-grained AP, 22 g of DAP-4, 3 g of nano desensitizer, 160 ml of absolute ethanol, 250 g of zirconium beads;

[0011] The DAP-4 / AN composite oxidizer includes the following components in the following weight percentages:

[0012] 25 g of coarse-grained AN, 22 g of DAP-4, 3 g of nano desensitizer, 160 ml of ethyl acetate, 250 g of zirconium beads;

[0013] Among them, the desensitizer is one or several mixtures of nano graphite, nano boron nitride or nano graphene; when the desensitizer is a mixture of several of nano graphite, nano boron nitride or nano graphene, the ratio between the components is 1:1 or 1:1:1.

[0014] When the mass fraction of AP or AN reaches more than 45 wt.%, the mixture will no longer be sensitive to mechanical friction stimulation. That is, [50 wt.% DAP-4 + 50 wt.% AP] or [50 wt.% DAP-4 + 50 wt.% AN] will become a very stable substance, and its friction sensitivity is comparable to that of pure AP or AN. Especially [50 wt.% DAP-4 + 50 wt.% AN], which can only be detonated by a detonator. Of course, since the friction sensitivity of AP itself is not too low, [50 wt.% DAP-4 + 50 wt.% AP] still has a certain degree of danger.

[0015] In [50 wt.% DAP-4 + 50 wt.% AP], after adding a small amount of nano desensitizers with high specific surface area and high lubricity (nano graphite, nano boron nitride, and / or nano graphene), the friction sensitivity of the mixture will drop linearly and reach a level similar to that of [50 wt.% DAP-4 + 50 wt.% AN]. Therefore, for solid propellants containing DAP-4, as long as the ratio of DAP-4 to AP or AN is controlled, the safe addition of DAP-4 can be achieved.

[0016] Preferably, the AP is ammonium perchlorate and the AN is ammonium nitrate.

[0017] The present invention also relates to a preparation method of the aforementioned high-energy and low-sensitivity ultrafine composite oxidizer containing DAP-4. The preparation method of the DAP-4 / AP composite oxidizer is as follows:

[0018] Step 1: The ball mill is equipped with four ball milling jars, each with a capacity of 250 mL, and there are four positions in the ball mill for fixing the ball milling jars symmetrically;

[0019] First, put in each jar: 25 grams of coarse-grained AP, 22 grams of DAP-4, 3 grams of nano desensitizer, 160 mL of ethyl acetate, and 250 grams of zirconium beads;

[0020] Then, seal the four jars, place them in the positions for fixing the jars in the ball mill, and start the ball milling and refining process; The mechanical ball milling method is adopted in the present invention, and the model of the ball mill used is the PM400 high-energy planetary mill produced by RETSCH Company in Germany. The grinding beads are zirconium beads with Ф = 5 mm (ZrO2 doped with 2% - 10% Y2O3 by mass content), produced by Yubang Industrial Ceramics Co., Ltd. in Zibo, Shandong. Compared with the jet refining method, the mechanical ball milling method has the characteristics of high technical output, less solvent usage, low reaction temperature, uniform powder particle size distribution, short cycle, and non-toxicity. This treatment method is a green and environmentally friendly explosive refining method.

[0021] Step 2: After ball milling is completed, stop the machine, take the material, filter out the material by suction, and then freeze-dry it for 24 hours to obtain ultrafine DAP-4 / AP composite oxidizer.

[0022] The preparation method of the DAP-4 / AN composite oxidizer is as follows:

[0023] Step 1: The ball mill is equipped with four ball milling jars, each with a capacity of 250 mL. There are four positions in the ball mill for fixing the ball milling jars symmetrically.

[0024] First, put in each jar: 25 g of coarse-grained AN, 22 g of DAP-4, 3 g of nano-sensitization reducer, 160 mL of ethyl acetate, and 250 g of zirconium beads.

[0025] Then, seal the four jars, place them in the positions for the jars in the ball mill and fix them, and start the ball milling and refining process.

[0026] Step 2: After ball milling is completed, stop the machine, take the material, filter out the material by suction, and then freeze-dry it for 24 hours to obtain ultrafine DAP-4 / AN composite oxidizer.

[0027] Preferably, the rotation speed of the ball mill is 250 rpm.

[0028] Preferably, the specific process of the mechanical ball milling and refining process is that the ball mill rotates forward for 2 minutes and then reverses for 2 minutes, and this process is carried out alternately in turn and ends after 2 hours.

[0029] Preferably, the d of the ultrafine DAP-4 / AP composite oxidizer 50 is 3 - 6 microns; the d of the ultrafine DAP-4 / AN composite oxidizer 50 is 3 - 6 microns.

[0030] The nano-sensitization reducer involved in the present invention plays the role of a lubricant. After the sensitization reducer is coated or doped in the middle of the ultrafine DAP-4 / AP or DAP-4 / AN composite oxidizer particles, the friction force between the ultrafine oxidizer particles will be greatly reduced, and the particles will be very smooth between each other, which plays a crucial role in greatly reducing the friction sensitivity of DAP-4. And when the friction force on the surface of the DAP-4 particles is greatly reduced, the dispersibility of the powder will also be greatly improved. In addition, the constituent element of nano-graphite or nano-graphene is carbon element, which will be completely oxidized into gaseous CO 2 during the combustion process and release a large amount of heat; while nano-boron nitride is composed of boron atoms and nitrogen atoms, which will form B 2 O 3 and N 2 gases during the combustion process of the propellant, thereby increasing the energy output of the propellant. This shows that the addition of a small amount of nano-sensitization reducer will not theoretically reduce the energy performance of the propellant.

[0031] The present invention has the following advantages:

[0032] (1) By adding a desensitizer which is coated or doped between ultrafine DAP-4 / AP or DAP-4 / AN composite oxidizer particles, the friction force between the ultrafine oxidizer particles will be greatly reduced, and the particles will be very smooth between each other, thereby greatly reducing the friction sensitivity of DAP-4 and obtaining a DAP-4-containing composite oxidizer with low sensitivity characteristics;

[0033] (2) The DAP-4-containing composite oxidizer prepared by the method of the present invention has the characteristic of good dispersibility;

[0034] (3) The raw materials involved in the present invention are all easily available, with low cost, no by-products generated, and environmental protection. Description of the Drawings

[0035] Figure 1 It is the SEM image of the nano-graphite involved in Example 1 of the present invention;

[0036] Figure 2 It is the SEM image of the nano-boron nitride involved in Example 2 of the present invention;

[0037] Figure 3 It is the SEM image of the nano-graphene involved in Example 3 of the present invention;

[0038] Figure 4 It is the SEM image of the composite oxidizer prepared in Example 4 of the present invention;

[0039] Figure 5 It is the SEM image of the composite oxidizer prepared in Example 8 of the present invention. Detailed Embodiments

[0040] The present invention will be described in detail below with reference to specific embodiments. It should be noted that the following embodiments are only for further illustration of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0041] Example 1

[0042] This example relates to a preparation method of an ultrafine [DAP-4 / AP + nano-graphite] composite oxidizer, including the following steps:

[0043] First, put in each jar: 25 grams of coarse-grained AP, 22 grams of DAP-4, 3 grams of nano-graphite, 160 milliliters of absolute ethanol, and 250 grams of zirconium beads; the SEM of the nano-graphite is shown in Figure 1 As shown, the thickness of the nano-graphite is less than 100 nm, and the width is close to 100 nm, belonging to nano-materials;

[0044] Then, seal the four jars, place them in the ball mill and fix them in the positions for the jars. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate in this way; the ball milling time is 2 hours without stopping in the middle.

[0045] Finally, after the ball milling is completed, stop the machine and take out the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AP + nano-graphite] composite oxidant.

[0046] Example 2

[0047] This example relates to a preparation method of an ultrafine [DAP-4 / AP + nano-boron nitride] composite oxidant, which includes the following steps:

[0048] First, put into each jar: 25 g of coarse-grained AP, 22 g of DAP-4, 3 g of nano-boron nitride, 160 ml of absolute ethanol, and 250 g of zirconium beads;

[0049] Then, seal the four jars, place them in the ball mill and fix them in the positions for the jars. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate in this way; the ball milling time is 2 hours without stopping in the middle; among them, the SEM image of nano-boron nitride is shown in Figure 2 as shown. Nano-boron nitride is in particle state, and its particle size is less than 100 nm, belonging to nano-materials;

[0050] Finally, after the ball milling is completed, stop the machine and take out the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AP + nano-boron nitride] composite oxidant.

[0051] Example 3

[0052] This example relates to a preparation method of an ultrafine [DAP-4 / AP + nano-graphene] composite oxidant, which includes the following steps:

[0053] First, put into each jar: 25 g of coarse-grained AP, 22 g of DAP-4, 3 g of nano-graphene, 160 ml of absolute ethanol, and 250 g of zirconium beads;

[0054] Then, seal the four jars, place them in the ball mill and fix them in the positions for the jars. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate in this way; the ball milling time is 2 hours without stopping in the middle; among them, the SEM image of nano-graphene is shown in Figure 3 as shown. The thickness of nano-graphene is less than 100 nm, and the width is close to 100 nm, belonging to nano-materials;

[0055] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AP + nano-graphene] composite oxidant.

[0056] Example 4

[0057] This example relates to a preparation method of an ultrafine [DAP-4 / AP + nano-graphene + nano-boron nitride + nano-graphene] composite oxidant, which includes the following steps:

[0058] First, put in each jar: 25 g of coarse-grained AP, 22 g of DAP-4, 1 g of nano-graphite, 1 g of nano-boron nitride, 1 g of nano-graphene, 160 mL of absolute ethanol, and 250 g of zirconium beads;

[0059] Then, seal the four jars, place them in the ball mill and fix them in the jar positions, set the rotation speed to 250 rpm, run forward for 2 minutes and then reverse for 2 minutes, alternating; the ball milling time is 2 hours without stopping in the middle;

[0060] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AP + nano-graphene + nano-boron nitride + nano-graphene] composite oxidant, as shown in Figure 4 shown, and all kinds of materials are very evenly mixed.

[0061] Example 5

[0062] This example relates to a preparation method of an ultrafine [DAP-4 / AN + nano-graphite] composite oxidant, which includes the following steps:

[0063] First, put in each jar: 25 g of coarse-grained AN, 22 g of DAP-4, 3 g of nano-graphite, 160 mL of ethyl acetate, and 250 g of zirconium beads;

[0064] Then, seal the four jars, place them in the ball mill and fix them in the jar positions, set the rotation speed to 250 rpm, run forward for 2 minutes and then reverse for 2 minutes, alternating; the ball milling time is 2 hours without stopping in the middle;

[0065] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AN + nano-graphite] composite oxidant.

[0066] Example 6

[0067] This example relates to a preparation method of an ultrafine [DAP-4 / AN + nano-boron nitride] composite oxidant, which includes the following steps:

[0068] First, put in each jar: 25 g of coarse-grained AN, 22 g of DAP-4, 3 g of nano boron nitride, 160 ml of ethyl acetate, and 250 g of zirconium beads;

[0069] Then, seal the four jars, place them in the ball mill and fix them in the jar positions. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate; the ball milling time is 2 hours without stopping in the middle;

[0070] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain ultrafine [DAP-4 / AN + nano boron nitride] composite oxidizer.

[0071] Example 7

[0072] This example relates to a preparation method of ultrafine [DAP-4 / AN + nano graphene] composite oxidizer, including the following steps:

[0073] First, put in each jar: 25 g of coarse-grained AN, 22 g of DAP-4, 3 g of nano graphene, 160 ml of ethyl acetate, and 250 g of zirconium beads;

[0074] Then, seal the four jars, place them in the ball mill and fix them in the jar positions. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate; the ball milling time is 2 hours without stopping in the middle;

[0075] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain ultrafine [DAP-4 / AN + nano graphene] composite oxidizer.

[0076] Example 8

[0077] This example relates to a preparation method of ultrafine [DAP-4 / AN + nano graphene + nano boron nitride + nano graphene] composite oxidizer, including the following steps:

[0078] First, put in each jar: 25 g of coarse-grained AN, 22 g of DAP-4, 1 g of nano graphite, 1 g of nano boron nitride, 1 g of nano graphene, 160 ml of ethyl acetate, and 250 g of zirconium beads;

[0079] Then, seal the four jars, place them in the ball mill and fix them in the jar positions. Set the rotation speed to 250 rpm. After running forward for 2 minutes, reverse for 2 minutes, and alternate; the ball milling time is 2 hours without stopping in the middle;

[0080] Finally, after the ball milling is completed, stop the machine and take the material. After filtering the material by suction, freeze-dry it for 24 hours to obtain the ultrafine [DAP-4 / AN + nano-graphene + nano-boron nitride + nano-graphene] composite oxidizer, as shown in Figure 5 It can be seen that all the materials are very uniformly mixed.

[0081] Comparative Example 1

[0082] First, put in a large mortar: 25 g of coarse-grained AP and 25 g of DAP-4;

[0083] Then, add 80 mL of absolute ethanol to the mortar;

[0084] After mixing the two evenly by grinding and drying, the [DAP-4 / AP] composite oxidizer is obtained.

[0085] Comparative Example 2

[0086] First, put in a large mortar: 25 g of coarse-grained AN and 25 g of DAP-4;

[0087] Then, add 80 mL of ethyl acetate to the mortar;

[0088] After mixing the two evenly by grinding and drying, the [DAP-4 / AN] composite oxidizer is obtained.

[0089] Compare the performance parameters of the samples in Examples 1-8 and Comparative Examples 1-2 above, as shown in Table 1 for details.

[0090] Table 1

[0091]

[0092] The parameter testing, calculation methods and conditions in Table 1 above:

[0093] (1) For the test of impact sensitivity, using the HGZ-1 sensitivity tester, adopting the 12-type tool method, referring to Method 601.3 in GJB 772A-97 to test the impact sensitivity of the sample. The height at which 50% explosion occurs is determined as the characteristic drop height, the drop hammer mass is 5 kg, the explosive mass is 35 mg, the temperature is 10 - 35 °C, the humidity is not more than 80%, and the test location is the Performance Testing Center of Detonating Explosives, North University of China, China Ordnance Industry.

[0094] (2) For the test of friction sensitivity, using the WM-1 friction sensitivity instrument, referring to Method 601.4 in GJB 772A-97 to test the friction sensitivity of the sample. The swing angle is 66°, the pressure is 2.45 MPa, 50 samples are tested in each batch, and the test location is the Performance Testing Center of Detonating Explosives, North University of China, China Ordnance Industry.

[0095] (3) For the measurement of the combustion heat, a special oxygen bomb calorimeter for propellants and explosives was used. According to the standard GJB 770B, Test Methods for Propellants, Method 701.1, Heat of Detonation and Combustion Heat, Adiabatic Method, the combustion heat of the test sample was measured. The sampling amount for each time was 0.1 g, and the test location was the Performance Detection Center of Initiating Explosive, China North University, China Ordnance Industry.

[0096] (4) For the calculation of the standard specific impulse and characteristic velocity, the special software NASA-CEA2 of the United States was used. The calculation conditions were: P c = 7 MPa, P e = 1 MPa, T 0 = 298 K, ΔH = 0. The software purchaser was the Performance Detection Center of Initiating Explosive, China North University, China Ordnance Industry.

[0097] For the impact sensitivity, the higher the H 50 , the more insensitive the sample. It can be seen from the data in Table 1 above that the impact sensitivity of Example 4 is significantly lower than that of Example 1, Example 2, Example 3 and the raw material DAP-4; and the impact sensitivity of Comparative Example 1 is also slightly lower than that of the raw material DAP-4. This shows that after doping DAP-4 with AP and adding nano-graphite, nano-boron nitride or (and) nano-graphene, its impact sensitivity decreases significantly and is lower than that of TNT.

[0098] For the friction sensitivity, the smaller the explosion percentage P, the more insensitive the explosive. It can be seen that the friction sensitivity of Example 4 is significantly lower than that of Example 1, Example 2, Example 3 and the raw material DAP-4; and the friction sensitivity of Comparative Example 1 is also slightly lower than that of the raw material DAP-4. This shows that after doping DAP-4 with AP and adding nano-graphite, nano-boron nitride or (and) nano-graphene, its friction sensitivity decreases significantly and is lower than that of TNT.

[0099] For the energy performance, the larger the values of the standard specific impulse I sp and the characteristic velocity C*, the higher the energy performance of the explosive. It can be seen from Table 1 that the I sp and C* of Example 1, Example 2, Example 3 and Example 4 are all greater than those of Comparative Example 1 and are close to the I sp and C* of the raw material DAP-4. This shows that the samples added with AP and nano-graphite, nano-boron nitride or (and) nano-graphene have energy performance similar to that of DAP-4.

[0100] Similarly, by comparing the data of Example 5, Example 6, Example 7, Example 8 and Comparative Example 2, it can be found that after doping DAP-4 with AN and adding nano-graphite, nano-boron nitride or (and) nano-graphene, its friction sensitivity and impact sensitivity decrease significantly and are lower than those of TNT.

[0101] Similarly, by comparing the data of Example 5, Example 6, Example 7, Example 8 and Comparative Example 2, it can be found that the samples added with AN and nano-graphite, nano-boron nitride or (and) nano-graphene have energy performance similar to that of DAP-4.

[0102] In summary, after mixing DAP-4 with AN and AP, the sensitivity is significantly reduced while the energy performance remains almost unchanged. In addition, nano-graphite, nano-boron nitride and nano-graphene have the characteristic of significantly reducing the sensitivity of the agent and have little impact on the energy performance of the agent.

[0103] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A high-energy, low-sensitivity ultrafine composite oxidant containing DAP-4, characterized in that: Including DAP-4 / AP composite oxidant and DAP-4 / AN composite oxidant; DAP-4 / AP composite oxidant includes the following components: 25g coarse AP, 22g DAP-4, 3g nano-sensitizer, 160ml anhydrous ethanol, 250g zirconium beads; DAP-4 / AN composite oxidant includes the following components in weight percentage: 25 g of coarse AN, 22 g of DAP-4, 3 g of nano-sensitizer, 160 ml of ethyl acetate, 250 g of zirconium beads; The desensitizing agent is one or a mixture of nano-graphite, nano-boron nitride or nano-graphene.

2. The DAP-4 high-energy low-sensitivity ultrafine composite oxidant according to claim 1, characterized in that: The AP is ammonium perchlorate, and the AN is ammonium nitrate.

3. A method for preparing the high-energy, low-sensitivity ultrafine composite oxidant containing DAP-4 as claimed in claim 1, characterized in that: The preparation method of the DAP-4 / AP composite oxidant is as follows: Step 1, put 25g of coarse AP particles, 22g of DAP-4, 3g of nano-sensitizer, 160ml of ethyl acetate, and 250g of zirconium beads into a ball mill and refine them by mechanical ball milling; Step 2, after the ball milling is completed, the machine is stopped, the material is taken out, the material is filtered out, and freeze-dried for 24 hours to obtain an ultrafine DAP-4 / AP composite oxidant; The preparation method of the DAP-4 / AN composite oxidant is as follows: Step 1, put 25g of coarse particle AN, 22g of DAP-4, 3g of nano-sensitizer, 160ml of ethyl acetate, and 250g of zirconium beads into a ball mill for mechanical ball milling; Step 2: After the ball milling is completed, the machine is stopped, the material is taken out, the material is filtered out, and freeze-dried for 24 hours to obtain an ultrafine DAP-4 / AN composite oxidant.

4. The method for preparing the high-energy, low-sensitivity ultrafine composite oxidant containing DAP-4 as claimed in claim 3, characterized in that: The rotation speed of the ball mill is 250 rpm.

5. The method for preparing the high-energy, low-sensitivity ultrafine composite oxidant containing DAP-4 as claimed in claim 3, characterized in that: The specific process of the mechanical ball milling refinement treatment is that the ball mill rotates forward for 2 minutes and then reverses for 2 minutes, and the process is repeated alternately, and the process ends after 2 hours.

6. The method for preparing the high-energy, low-sensitivity ultrafine composite oxidant containing DAP-4 as claimed in claim 3, characterized in that: The ultrafine DAP-4 / AP composite oxidant 50 The ultrafine DAP-4 / AN composite oxidant has a d 50 3-6 microns.

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