Potassium perchlorate / zinc-magnesium alloy composite energetic material for mechanical detonation

Abstract

The invention discloses a potassium perchlorate / zinc-magnesium alloy composite energetic material for mechanical detonation, which comprises the following components in percentage by weight: 70% of potassium perchlorate and 30% of zinc-magnesium alloy powder, the mass fraction of magnesium in the zinc-magnesium alloy powder is 50-80%, and the zinc-magnesium alloy powder is prepared by adding Zn powder into Mg powder through a centrifugal atomization method. According to the method, zinc is added into magnesium to prepare the zinc-magnesium alloy, so that an oxidation shell layer on the surface of metal powder is broken through, diffusion of magnesium is promoted, the reaction activity and energy output of the magnesium-based composite energetic material are remarkably improved, and energy release of the magnesium-based composite energetic material is more concentrated. The impact sensitivity and the friction sensitivity of the formula are high, and the excellent detonation sensitivity can be shown under the high-speed impact condition.

Description

Technical Field

[0001] The present invention relates to the technical field of pyrotechnics and explosives, and particularly to a potassium perchlorate / zinc-magnesium alloy composite energetic material for mechanical initiation. Background Art

[0002] Primary explosives are a type of energetic material that can initiate its own explosion reaction through external stimuli (such as impact, flame, etc.) and transfer the explosion energy to the main explosive. The mechanical action initiation mechanism means that when an explosive is impacted or rubbed, mechanical energy is first converted into heat energy and accumulates in a small local area to form a "hot spot". Thermal decomposition occurs at the hot spot. Due to the exothermic nature of the decomposition, the decomposition rate increases rapidly, and a strong reaction forms within the hot spot, causing all or part of the explosive to explode. With the continuous development of military and civilian industrial demands, primary explosives need to have properties such as high sensitivity, high detonation velocity, high heat release, good thermal stability, and safety. Traditional primary explosives can no longer meet the usage requirements in terms of formulation and preparation process.

[0003] Potassium perchlorate will undergo a decomposition reaction when exposed to high temperatures or strong impacts, releasing oxygen and generating a large amount of heat, resulting in a sharp rise in pressure and triggering an explosion. Compared with ammonium perchlorate, potassium perchlorate has higher chemical stability and lower hygroscopicity, making it suitable for use in humid environments to ensure the long-term stability of primary explosives. However, the thermal stability of potassium perchlorate is relatively high, and its decomposition peak temperature is usually between 500°C and 600°C, which limits its ignition ability and energy release performance under mechanical impact. In addition, due to the lack of participation of combustibles, the explosion power of potassium perchlorate is limited.

[0004] Existing research shows that adding metal powders to potassium perchlorate can effectively promote the thermal decomposition of potassium perchlorate, increase its energy release rate, and the energy output of the reaction system. Some studies have prepared composite energetic materials by adding magnesium powder to potassium perchlorate, significantly increasing the temperature and energy release rate of the reaction system, thereby enhancing its explosion performance. However, magnesium has active chemical properties and is easily oxidized. The high-melting-point oxide shell layer formed on its surface poses a huge challenge to the ignition performance and combustion stability of magnesium-based composite energetic materials. This high-melting-point oxide shell layer results in a relatively high ignition temperature of magnesium-based composite energetic materials, thus limiting the full play of their advantages. Therefore, how to effectively improve the reaction activity of magnesium / potassium perchlorate composite energetic materials while maintaining high energy output has become a key technical problem in the development of new primary explosives. Summary of the Invention

[0005] Aiming at the defects or deficiencies of the existing technology, the present invention provides a potassium perchlorate / zinc-magnesium alloy composite energetic material for mechanical initiation to meet the performance requirements of new primary explosives.

[0006] To this end, in a first aspect, the present invention provides a potassium perchlorate / zinc-magnesium alloy composite energetic material, which is a mixture composed of potassium perchlorate and zinc-magnesium alloy powder.

[0007] Further, the zinc-magnesium alloy powder is prepared by adding Zn powder to Mg powder through centrifugal atomization.

[0008] Further, the mass fraction of potassium perchlorate is 70%, and the mass fraction of zinc-magnesium alloy powder is 30%.

[0009] Further, the mass percentage of magnesium in the zinc-magnesium alloy powder is 50-80%.

[0010] Further, the particle size range of the zinc-magnesium alloy powder is 70-150 μm.

[0011] Further, the zinc-magnesium alloy powder is prepared by the following steps:

[0012] S1. Uniformly mix zinc powder and magnesium powder in a furnace in a centrifugal atomization system;

[0013] S2. Pump the furnace chamber to vacuum and backfill with an inert gas as a protective gas;

[0014] S3. Heat the mixture of zinc powder and magnesium powder to 700-800 °C to melt it;

[0015] S4. Transport the melt to a high-speed rotating atomization disk. Under the action of centrifugal force, the melt forms small droplets after passing through a cooling tower and then solidifies into a magnesium-zinc alloy;

[0016] S5. Screen and collect powders with a particle size of 70-150 μm to obtain the zinc-magnesium alloy powder.

[0017] Even further, in step S2, the vacuum degree required for pumping the furnace chamber to vacuum is 10 -3 -10 -2 Pa, and the inert gas is one of pure argon (99.99%), pure nitrogen (99.99%), or pure helium (99.99%).

[0018] In a second aspect, the present invention also provides a preparation method of the potassium perchlorate / zinc-magnesium alloy composite energetic material described in the first aspect, including the following steps:

[0019] Disperse potassium perchlorate and the zinc-magnesium alloy powder in an organic solution and ultrasonically treat for 30-60 min; after filtration, place it in a fume hood for 18-24 h to obtain the potassium perchlorate / zinc-magnesium alloy composite energetic material.

[0020] Further, the organic solution is one of hexane, absolute ethanol, or acetone.

[0021] In a third aspect, the present invention provides a use of the potassium perchlorate / zinc-magnesium alloy composite energetic material described in the first aspect as a primary explosive.

[0022] Further, the primary explosive is initiated mechanically.

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

[0024] The results of thermal performance tests show that: compared with potassium perchlorate / magnesium, the exothermic peak temperature of the potassium perchlorate / zinc-magnesium alloy of the present invention decreases from 611.76 °C (low-temperature exothermic peak) to 453.50 °C or lower, the peak value of the heat release increases from 1.66 mW to 17.89 mW or higher, and the heat release is more concentrated.

[0025] The results of sensitivity tests show that: compared with potassium perchlorate / magnesium, the impact sensitivity of the potassium perchlorate / zinc-magnesium alloy of the present invention decreases from 11 J to 4 J or lower, and the friction sensitivity increases from 50% to 80% or higher, and its initiation sensitivity under mechanical impact is greatly enhanced.

[0026] Among them, the zinc-magnesium alloy powder prepared by the centrifugal atomization method has high purity, good sphericity, narrow particle size distribution, uniform zinc distribution, and this method has low cost and high production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the drawings and specific embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts. Among them:

[0028] Figure 1 TG-DSC curve of the potassium perchlorate / zinc-magnesium alloy prepared in Example 1;

[0029] Figure 2 TG-DSC curve of the potassium perchlorate / zinc-magnesium alloy prepared in Example 2;

[0030] Figure 3 TG-DSC curve of the potassium perchlorate / magnesium prepared in Comparative Example 1;

[0031] Figure 4 TG-DSC curve of the potassium perchlorate / zinc prepared in Comparative Example 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present application will be further described below in conjunction with specific embodiments.

[0033] It should be noted that terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear description and are not used to limit the scope of implementation. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope within which this application can be implemented.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0035] For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0036] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. Those skilled in the art can easily determine the degree of flexibility of a specific variable.

[0037] As used herein, the term "at least one of..." is intended to be synonymous with "one or more of...". For example, "at least one of A, B, and C" clearly includes only A, only B, only C, and their respective combinations.

[0038] Concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such a range format is used only for convenience and brevity and should be interpreted flexibly as including not only the numerical values explicitly recited as the limits of the range, but also all individual numerical values or sub-ranges subsumed within the stated range as if each numerical value and sub-range were explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted as including not only the explicitly recited limit values of 1 to about 4.5, but also the individual numbers (such as 2, 3, 4) and sub-ranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that recite only one numerical value, such as "less than about 4.5", which should be interpreted as including all of the above values and ranges. In addition, this interpretation should apply regardless of the breadth of the range or feature described.

[0039] The concept of the present invention is as follows: Magnesium has active chemical properties and is easily oxidized. The high-melting-point oxide shell layer formed on its surface will result in a relatively high ignition temperature of the magnesium-based composite energetic material, thus limiting the full play of its advantages. The melting point and boiling point of zinc are both lower than those of magnesium, and at 600 °C and 900 °C, the saturated vapor pressure of zinc is more than 10 times higher than that of magnesium. This indicates that zinc is easy to melt and vaporize. Adding zinc to magnesium to prepare a zinc-magnesium alloy can effectively break through the oxide shell on the surface of the metal powder and promote the diffusion process of magnesium, thereby improving the reaction activity and energy output of the magnesium-based composite energetic material.

[0040] Example 1

[0041] The preparation raw materials of this example are as follows: potassium perchlorate 70%, zinc powder 6%, magnesium powder 24%;

[0042] The preparation method of the zinc-magnesium alloy in this example is as follows: Mix 6 g of zinc powder and 24 g of magnesium powder evenly in a furnace in a centrifugal atomization system. Then, evacuate the furnace chamber to a vacuum (10 -2 Pa), and backfill with pure argon (99.99%) as the protective gas; Raise the temperature in the furnace chamber to 750 °C to melt the zinc powder and magnesium powder. The melt is transported to the atomization chamber through a conveying pipeline and then enters a high-speed rotating atomization disk through a diversion pipe; Under the action of centrifugal force, the melt forms small droplets after passing through a cooling tower and then solidifies into a magnesium-zinc alloy; Screen and collect the zinc-magnesium alloy powder with a particle size of 100 μm to obtain the zinc-magnesium alloy powder of this example.

[0043] The preparation method of the potassium perchlorate / zinc-magnesium alloy composite energetic material in this example is as follows: Disperse 70 g of potassium perchlorate and 30 g of zinc-magnesium alloy powder in hexane and ultrasonicate for 40 min; After filtration, place it in a fume hood for 24 h to obtain the potassium perchlorate / zinc-magnesium alloy composite energetic material of this example.

[0044] Example 2

[0045] Different from Example 1, this example is implemented according to the following mass percentage composition: potassium perchlorate 70%, zinc powder 15%, magnesium powder 15%, and other processes are the same as those in Example 1.

[0046] Comparative Example 1

[0047] Different from Example 1, this comparative example is implemented according to the following mass percentage composition: potassium perchlorate 70%, magnesium powder 30%.

[0048] The preparation method of the potassium perchlorate / magnesium composite energetic material in this comparative example is as follows: Disperse 70 g of potassium perchlorate and 30 g of magnesium powder in hexane and ultrasonicate for 40 min; After filtration, place it in a fume hood for 24 h to obtain the potassium perchlorate / magnesium composite energetic material of this comparative example.

[0049] Comparative Example 2

[0050] Different from Example 1, this comparative example was prepared according to the following mass percentage composition: potassium perchlorate 70%, zinc powder 30%.

[0051] The preparation method of this comparative example refers to Comparative Example 1.

[0052] The products prepared from the above examples and comparative examples were further subjected to the following performance tests:

[0053] (1) Ignition performance and thermodynamic reaction process test, the test method is as follows:

[0054] Tested with a TG-DSC instrument from Mettler Toledo. Each time, 0.5 mg of the sample was added to the crucible and placed into the furnace body. High-purity nitrogen was used as the protective gas in the furnace body (gas velocity: 20 mL / min), and air was used as the reaction gas (gas velocity: 50 mL / min). The measurement temperature range was 50 - 800 °C, and the heating rate was 20 °C / min. The temperature, heat, and weight changes of the sample during heating were measured. The program control, data recording, and analysis were all completed by the STARe Software 10.0 developed by Mettler.

[0055] The TG-DSC test results of the potassium perchlorate / zinc-magnesium alloy prepared in Example 1 and Example 2 are respectively as Figure 1 and Figure 2 shown. The TG-DSC test result of the potassium perchlorate / magnesium prepared in Comparative Example 1 is as Figure 3 shown. It can be seen from Figures 1 to 3 that the potassium perchlorate / zinc-magnesium alloy of the present invention releases heat more concentratedly compared with potassium perchlorate / magnesium. When the mass percentage of zinc in the zinc-magnesium alloy is 20%, the temperature of the low-temperature exothermic peak advances from 611.76 °C to 453.50 °C, and the peak value of the heat release increases from 1.66 mW to 17.89 mW. When the mass percentage of zinc in the zinc-magnesium alloy is 50%, the temperature of the low-temperature exothermic peak advances to 444.94 °C, and the peak value of the heat release increases to 34.0 mW, and the heat release is more concentrated compared with Example 1. The above results show that introducing zinc on the basis of traditional potassium perchlorate / magnesium to prepare potassium perchlorate / zinc-magnesium alloy can significantly improve the reaction activity, energy release rate, and energy output of the composite energetic material.

[0056] The TG-DSC test result of the potassium perchlorate / zinc prepared in Comparative Example 2 is as Figure 4 shown. It can be seen from Figure 4It can be seen that when the metal powder is pure zinc, the low-temperature exothermic peak temperature of the composite energetic material is as high as 613.64 °C, the peak heat release is only 4.3 mW, and the heat release is not concentrated, which is similar to the case when the metal powder is pure magnesium. The main reason for this phenomenon is that the chemical properties of pure zinc and pure magnesium are extremely active and they easily react with oxygen to form a high-melting-point oxide shell on their surfaces, which severely inhibits the reaction activity of the composite energetic material.

[0057] (2) Impact sensitivity test, the test method is as follows:

[0058] The test is carried out using a BAM falling weight impact sensitivity tester, and the impact sensitivity of the sample is characterized by the impact energy method. The smaller the impact energy, the greater the impact sensitivity of the sample. The test is carried out in accordance with Method 601 of GJB772A-1997.

[0059] (3) Friction sensitivity test, the test method is as follows:

[0060] The test is carried out using a BAM friction tester, and the friction sensitivity of the sample is characterized by the explosion percentage. The greater the explosion percentage, the greater the friction sensitivity of the sample. The test is carried out in accordance with Method 602 of GJB772A-1997.

[0061] The impact sensitivity test results and friction sensitivity test results of the products prepared in the above examples and comparative examples are shown in Table 1:

[0062] Table 1

[0063]

[0064] As can be seen from Table 1, when comparing Example 1 with Comparative Example 1, that is, when the metal powder is replaced from pure magnesium with the zinc-magnesium alloy (Zn-Mg, Zn 20 wt%) of the present invention, the impact energy of the composite energetic material is significantly reduced from 11 J to 4 J, and the explosion percentage of the friction sensitivity is significantly increased from 50% to 80%. When comparing Example 2 with Example 1, that is, when the mass percentage of zinc in the zinc-magnesium alloy is increased from 20% to 50%, the impact energy of the composite energetic material can be reduced to 2 J, and the explosion percentage of the friction sensitivity can be increased to 85%. When comparing Comparative Example 2 with Example 1 and Example 2, that is, when the metal powder is pure zinc, the impact energy of the composite energetic material rebounds to 10 J, which is similar to that of Comparative Example 1, and the explosion percentage of the friction sensitivity drops to 50%, which is the same as that of Comparative Example 1. Thus, it can be seen that the impact sensitivity and friction sensitivity of the potassium perchlorate / zinc-magnesium alloy of the present invention are greatly improved compared with the traditional potassium perchlorate / magnesium, and it can show more excellent initiation sensitivity under high-speed impact conditions.

[0065] The above embodiments are only the preferred embodiments of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. For example, combinations of various forms of the solutions in the embodiments, any other changes, modifications, substitutions, and combinations made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all within the protection scope of the present invention.

Claims

1. A potassium perchlorate / zinc-magnesium alloy composite energetic material, characterized in that: It is a mixture of potassium perchlorate and zinc-magnesium alloy powder.

2. The composite energetic material according to claim 1, characterized in that: The mass fraction of potassium perchlorate is 70%, and the mass fraction of zinc-magnesium alloy powder is 30%.

3. The composite energetic material according to claim 1, characterized in that: Zinc-magnesium alloy powder is prepared by adding Zn powder to Mg powder through centrifugal atomization.

4. The composite energetic material according to claim 1 or 3, characterized in that: The mass percentage of magnesium in the zinc-magnesium alloy powder is 50 to 80%.

5. The composite energetic material according to claim 1 or 3, characterized in that: The particle size of the zinc-magnesium alloy powder ranges from 70 to 150 μm.

6. The composite energetic material according to claim 1 or 3, characterized in that: The zinc-magnesium alloy powder is prepared by the following steps: S1. Evenly mix zinc powder and magnesium powder in a furnace in a centrifugal atomization system; S2, evacuate the furnace to a vacuum and backfill with inert gas as protective gas; S3, heating the mixture of zinc powder and magnesium powder to 700-800° C. to melt the mixture; S4, transporting the melt to a high-speed rotating atomizing disk, under the action of centrifugal force, the melt forms small droplets after passing through a cooling tower, and then solidifies into a magnesium-zinc alloy; S5. Screen and collect powders with a size of 70 to 150 μm to obtain the zinc-magnesium alloy powder.

7. A method for preparing a potassium perchlorate / zinc-magnesium alloy composite energetic material as claimed in any one of claims 1 to 6, characterized in that: The steps include: The potassium perchlorate and the zinc-magnesium alloy powder are dispersed in an organic solution, and ultrasonicated for 30 to 60 minutes; after filtering, the solution is placed in a fume hood for 18 to 24 hours to obtain a potassium perchlorate / zinc-magnesium alloy composite energetic material.

8. The method according to claim 7, characterized in that The organic solvent is one of hexane, anhydrous ethanol or acetone.

9. Use of the potassium perchlorate / zinc-magnesium alloy composite energetic material as claimed in any one of claims 1 to 6 as a detonating explosive.

10. The use according to claim 9, characterized in that The explosive is detonated mechanically.

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