阅读说明：本技术 花状核壳结构复合含能材料及其制备方法 (Flower-shaped core-shell structure composite energetic material and preparation method thereof ) 是由 黎学明 何银芳 杨文静 何苗 谢玉婷 雷颖 杨磊 龚子雯 于 2021-09-23 设计创作，主要内容包括：花状核壳结构复合含能材料及其制备方法。该方法包括：将氯化镍、柠檬酸三钠和氨水形成的混合溶液转移到水热反应釜进行水热反应；将水热反应产物离心分离并干燥后得到前驱体；将所得前驱体煅烧后得到空心花状NiO；再将所得空心花状NiO和纳米Al粉超声分散于乙醇中形成悬浮液；干燥所得悬浮液后即得Al/NiO复合含能材料或铝热剂。本发明制备的花状核壳结构铝热剂能有效增加Al粉与NiO的接触面积,显著提高铝热剂的热反应性能及能量释放效率和速率。(A flower-shaped core-shell structure composite energetic material and a preparation method thereof. The method comprises the following steps: transferring a mixed solution formed by nickel chloride, trisodium citrate and ammonia water to a hydrothermal reaction kettle for hydrothermal reaction; centrifugally separating and drying the hydrothermal reaction product to obtain a precursor; calcining the precursor to obtain hollow flower-shaped NiO; ultrasonically dispersing the obtained hollow flower-shaped NiO and the nano Al powder in ethanol to form a suspension; and drying the obtained suspension to obtain the Al/NiO composite energetic material or the thermite. The flower-shaped core-shell structure thermit prepared by the invention can effectively increase the contact area of Al powder and NiO, and obviously improve the thermal reaction performance, energy release efficiency and rate of the thermit.)

1. A preparation method of an Al/NiO composite energetic material comprises the following steps:

forming a mixed solution of nickel chloride, trisodium citrate and ammonia water, wherein the concentration of the nickel chloride is 0.05-0.1 mol/L, the concentration of the trisodium citrate is 5-15 mmol/L, and the concentration of the ammonia water is 0.5-1.5 mol/L;

transferring the obtained mixed solution to a hydrothermal reaction kettle for hydrothermal reaction, wherein the hydrothermal reaction temperature is 140-200 ℃, and the reaction time is 8-16 h;

centrifugally separating and drying the hydrothermal reaction product to obtain a precursor;

calcining the precursor to obtain hollow flower-shaped NiO, wherein the calcining temperature is 400-600 ℃, and the calcining time is 4-8 h;

ultrasonically dispersing the obtained hollow flower-shaped NiO and nano Al powder in ethanol to form a suspension, wherein the mass ratio of NiO to nano Al powder is (1-3): 1;

and drying the obtained suspension to obtain the Al/NiO composite energetic material.

2. The method according to claim 1, wherein the temperature increase rate during the calcination is 2 to 5 ℃/min.

3. An Al/NiO composite energetic material prepared according to the method of claim 1 or 2.

Technical Field

The invention relates to a thermite and a preparation method thereof.

Background

The thermite is a mixture of metal aluminum particles and metal oxides, and is widely applied to the fields of ignition, micro-pushing, welding and the like due to the advantages of high energy density, high reaction activity and the like. However, the common thermite often has the defects of uneven particle dispersion, slow combustion speed, non-centralized heat release and the like, and cannot well meet the application requirement of the high-performance thermite.

In order to strengthen the performance of thermite and realize the unification of high energy density and high electrostatic safety, researches find that increasing the contact area of fuel and oxidant can improve the reaction rate of the nano composite energetic material, and therefore, the fuel and oxidant are assembled into a compact and orderly arranged structure, which is recently paid great attention. At present, the methods for preparing NiO with different shapes mainly comprise a sol-gel method, an electrophoretic deposition method, a liquid phase reduction method, a self-assembly method and the like, and the preparation methods are all thousands of years, but have respective defects.

In conclusion, the research and development of a new simple synthesis method can realize the economic and environment-friendly preparation of the thermite with different morphologies under mild conditions, effectively improve the contact area of Al and metal oxide, and improve the energy release level and the heat release performance of the thermite.

Disclosure of Invention

The object of the present invention is to provide a thermite having improved properties.

According to the first aspect of the invention, the preparation method of the Al/NiO composite energetic material comprises the following steps:

forming a mixed solution of nickel chloride, trisodium citrate and ammonia water, wherein the concentration of the nickel chloride is 0.05-0.1 mol/L, the concentration of the trisodium citrate is 5-15 mmol/L, and the concentration of the ammonia water is 0.5-1.5 mol/L;

transferring the obtained mixed solution to a hydrothermal reaction kettle for hydrothermal reaction, wherein the hydrothermal reaction temperature is 140-200 ℃, and the reaction time is 8-16 h;

centrifugally separating and drying the hydrothermal reaction product to obtain a precursor;

calcining the precursor to obtain hollow flower-shaped NiO, wherein the calcining temperature is 400-600 ℃, and the calcining time is 4-8 h;

ultrasonically dispersing the obtained hollow flower-shaped NiO and nano Al powder in ethanol to form a suspension, wherein the mass ratio of NiO to nano Al powder is (1-3): 1;

and drying the obtained suspension to obtain the Al/NiO composite energetic material.

According to the invention, the heating rate during calcination is preferably 2-5 ℃/min.

According to another aspect of the invention, an Al/NiO composite energetic material is also provided, which is prepared according to the method.

Compared with the prior art, the invention has at least the following advantages:

(1) the invention increases the contact area between the metal oxide and Al by preparing the hollow flower-shaped NiO with a novel structure;

(2) when the single nickel source is used for preparing the hollow flower-shaped NiO, no impurities are generated, and the hollow flower-shaped NiO has regular and uniform macropores, so that the nanometer aluminum powder can enter the hollow flower-shaped NiO easily, and the reactivity is high;

(3) the preparation process has the advantages of low cost, few steps and simplicity and feasibility.

Drawings

FIG. 1 is an XRD pattern of a floriated NiO prepared according to an example of the invention;

FIG. 2 is an XRD (X-ray diffraction) pattern of a flower-shaped core-shell structure Al/NiO composite energetic material prepared according to an embodiment of the invention;

FIGS. 3(a), (b) and (c) are SEM images of the hollow flower-like NiO and the flower-like core-shell structure Al/NiO composite energetic material prepared according to the embodiment of the invention; and

FIG. 4 is a DSC exothermic curve of flower-like core-shell structure Al/NiO composite energetic material prepared according to the embodiment of the invention.

Detailed Description

The invention is further illustrated by the following specific examples.

Examples

Step 1: weighing 0.1g of trisodium citrate, dissolving in 37mL of deionized water, then adding 0.5g of nickel chloride, adding 3mL of ammonia water (the concentration is 1mol/L) after complete dissolution, magnetically stirring for 20min to form a reaction solution, transferring the reaction solution to a 100mL reaction kettle, reacting for 9h at 150 ℃, cooling to room temperature, centrifuging, washing for several times by using deionized water and ethanol in sequence, and finally placing the reaction solution in a vacuum drying oven for drying to obtain a precursor.

Step 2: and (3) placing the precursor powder obtained in the step (1) in a muffle furnace, calcining for 6h at 400 ℃ under the air condition, heating at the rate of 5 ℃/min, and cooling to room temperature to obtain the hollow flower-shaped NiO.

And step 3: accurately weighing 0.042g of nano aluminum powder and 0.058g of NiO, wherein the mass ratio of NiO to nano Al powder is 1.38:1 (the equivalent ratio is 3), dissolving the NiO and the nano Al powder in 15mL of ethanol solvent, performing ultrasonic treatment for 30min to form uniform suspension, and drying the suspension at 80 ℃ to obtain the flower-shaped core-shell structure Al/NiO composite energetic material.

The obtained hollow flower-like NiO and flower-like core-shell structure Al/NiO are characterized, and the results are shown in FIGS. 1-4. FIGS. 1-2 show XRD of the hollow flower-like NiO and the flower-like core-shell structure Al/NiO prepared in the above examples, and the results are shown in the following graphs, wherein the diffraction peaks appear at 37.2 °, 43.3 °, 62.9 °, 75.4 ° and 79.4 °, which correspond to the standard diffraction card of NiO (PDF #47-1049), no any impurity peak appears on the graph, and the product is pure, sharp in peak shape and high in crystallinity. The diffraction peaks for Al in FIG. 2 appear at 38.5 °, 44.7 °, 65.1 °, 78.2 °, 82.4 °, corresponding to the standard diffraction card for Al (PDF #04-0787), and there is no Al₂O₃A hetero-peak appears, further indicating that the two did not react during mixing. FIGS. 3a and 3b are SEM images of the flower-like NiO prepared in the above example, wherein FIG. 3a is a high magnification view; as shown in the figure, the diameter of the prepared NiO is 3-5 μm, the size is uniform, the surface is flower-shaped, and the pore diameter is large. FIG. 3(c) is an SEM image of flower-like core-shell structure Al/NiO prepared in the above example, and it can be seen from the SEM image that a small amount of nano Al powder is attached to the surface of flower-like NiO and a large amount of Al powder enters into hollow flower-like shape through poresAnd a core-shell structure is formed inside the NiO, so that the contact area is effectively increased. FIG. 4 is a DSC exothermic curve of flower-like core-shell structure Al/NiO prepared in the above example, wherein the temperature rise range is from room temperature to 900 ℃, the temperature rise rate is 20 ℃/min, the Ar atmosphere has an exothermic peak, and belongs to the solid-state reaction of Al and NiO, the reaction heat is 1513.5J/g, and the peak temperature is 603 ℃. In addition, the current reaches high temperature through the resistance wire to ignite the Al/NiO composite material, and the combustion process is accompanied by a large amount of spark sputtering and strong detonation.