Nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide as well as preparation method and application of nano-composite thermite

Abstract

The invention belongs to the technical field of energetic materials, and discloses a nano-composite thermite composed of a gallium-aluminum alloy and a three-dimensional porous oxide and a preparation method and application of the nano-composite thermite. According to the method, a novel thermite is developed through component regulation and structural design, generation of a complete and uniform Al2O3 passivation layer on the surface of the aluminum fuel is inhibited by introducing liquid metal gallium, and meanwhile, the activity of nano aluminum is protected, the contact degree of thermite components is enhanced and the mass transfer diffusion length is shortened by combining the confinement effect of different three-dimensional porous oxidants; and thus, the high-performance aluminum-gallium-based nano-composite thermite is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic materials, and in particular relates to a nano composite thermite composed of gallium aluminum alloy and three-dimensional porous oxide, and a preparation method and application thereof. Background Art

[0002] Thermite is a composite energetic material composed of fuel and oxidant, which can undergo a violent redox reaction under certain excitation conditions and release a large amount of heat. Aluminum, magnesium, silicon and other single substances can be used as fuels, among which aluminum powder is the first choice because of its low price and high calorific value; while the oxidant is mainly metal oxides such as iron oxide (Fe2O3), copper oxide (CuO), and molybdenum oxide (MoO3). A large number of studies have shown that reducing the micron-sized components of thermite to nanometer size can significantly increase the heat release and reduce the ignition energy. A large number of studies have shown that reducing the particle size of thermite components from micron to nanometer, and through component regulation (additives, alloying, etc.) or special structural design (multilayer structure, porous structure, three-dimensional array and core-shell structure) and other strategies can effectively improve thermite performance. However, on the one hand, nano-aluminum has the problem of difficult processing and difficulty in large-scale supply of nano-aluminum powder. On the other hand, compared with micron-sized aluminum, nano-aluminum is more likely to be oxidized on the particle surface during the preparation of thermite and subsequent storage to form a dense passivated aluminum oxide shell, thereby hindering the reaction between the internal aluminum core and the oxidant, resulting in the inability to fully exert the performance of thermite in practical applications. Summary of the invention

[0003] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art that cannot fully meet the requirements of easy oxidation of nano-sodium and precise control of uniformity and dispersion of thermite components, the primary purpose of the present invention is to provide a method for preparing a nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide; the method develops a new type of thermite through component control and structural design, and suppresses the formation of a complete and uniform Al2O3 passivation layer on the surface of aluminum fuel by introducing liquid metal gallium, while combining the confinement effect of different three-dimensional porous oxidants to protect the activity of nano-aluminum, enhance the contact degree of thermite components and shorten the mass transfer diffusion length, thereby obtaining a high-performance aluminum-gallium-based nano-composite thermite.

[0004] Another object of the present invention is to provide a nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide prepared by the above preparation method.

[0005] Another object of the present invention is to provide an application of the nanocomposite thermite composed of the gallium-aluminum alloy and the three-dimensional porous oxide.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a nano-composite thermite composed of a gallium-aluminum alloy and a three-dimensional porous oxide comprises the following steps:

[0008] (1) placing liquid metal gallium in a sealed container, adding a metal aluminum foil that has been polished to remove the surface oxide film into the liquid metal gallium under the protection of an inert atmosphere, and then heating the aluminum foil to react to prepare a low-melting-point gallium-aluminum alloy; the mass ratio of gallium to aluminum in the low-melting-point gallium-aluminum alloy is in the range of 1:2 to 2:1;

[0009] (2) Preparation of three-dimensional ordered macroporous oxides by colloidal crystal template method: a monodisperse polymer colloidal microsphere dispersion is self-assembled into a three-dimensional ordered macroporous colloidal crystal skeleton by vacuum filtration, and then a metal salt is impregnated and filled into the pores of the three-dimensional ordered macroporous colloidal crystal skeleton by a solution impregnation method, and after calcination at 300-500° C. for 5-10 h in an air atmosphere, the colloidal template is decomposed and the metal salt is pyrolyzed and oxidized, thereby obtaining the corresponding three-dimensional ordered macroporous oxide; the metal salt is a copper salt, a zinc salt or a cobalt salt;

[0010] (3) Preparation of three-dimensional porous oxide foil by dealloying method: using copper alloy foil or molybdenum alloy foil as a template, the copper alloy foil is an alloy of at least one of the active components Zn, Mn and Mg with copper, and the molybdenum alloy foil is an alloy of at least one of the active components Zn, Mn and Mg with molybdenum; immersing the copper alloy foil or molybdenum alloy foil in a dilute acid solution for 12-24 hours to dissolve and remove the active components therein, thereby obtaining a three-dimensional continuous porous copper or molybdenum skeleton with adjustable pore type and size, and then heat treating the three-dimensional continuous porous copper or molybdenum skeleton at 300-500°C for 1-5 hours in an air atmosphere to oxidize the surface of the three-dimensional continuous porous copper or molybdenum skeleton to form a layer of copper oxide or molybdenum trioxide to form a three-dimensional porous oxide foil;

[0011] (4) mixing and heating the low-melting-point gallium-aluminum alloy obtained in step (1) and the three-dimensional ordered macroporous oxide obtained in step (2) in an argon atmosphere, and subjecting the low-melting-point gallium-aluminum alloy to heat treatment at 200-300° C. to melt the low-melting-point gallium-aluminum alloy into a liquid state, and then pouring the liquid into the three-dimensional ordered macroporous oxide obtained in step (2), thereby achieving the composite of the gallium-aluminum alloy fuel and the three-dimensional ordered macroporous oxide, and obtaining a nanocomposite thermite composed of the gallium-aluminum alloy and the three-dimensional porous oxide;

[0012] (5) The three-dimensional porous oxide foil obtained in step (3) and the low-melting-point gallium-aluminum alloy obtained in step (1) are sequentially stacked on a flat heater, and the low-melting-point gallium-aluminum alloy is melted into a liquid state after heating at 200-300° C., and then poured into the three-dimensional porous oxide foil, thereby realizing the composite of gallium-aluminum alloy fuel and the three-dimensional porous oxide foil, and obtaining a nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide.

[0013] The inert gas in step (1) is argon; the temperature range of the heating reaction is 200-300°C, and the time range is 3-5h.

[0014] The melting point of the low melting point gallium aluminum alloy in step (1) is ≤300°C.

[0015] The monodisperse polymer colloidal microspheres in step (2) are monodisperse polystyrene (PS) colloidal microspheres or polymethyl methacrylate microspheres (PMMA); the solid content of the monodisperse polymer colloidal microsphere dispersion is 10wt%; the volume range of the monodisperse polymer colloidal microsphere dispersion is 10-60ml; the size of the monodisperse polymer colloidal microspheres is 50-500nm.

[0016] The solution impregnation method in step (2) is to prepare the metal salt into a metal salt solution with a concentration of 0.05-0.2 mol / L for impregnation.

[0017] The dilute acid solution in step (3) is 0.5-1 mol / L hydrochloric acid.

[0018] A nano composite thermite composed of gallium aluminum alloy and three-dimensional porous oxide prepared by the above preparation method.

[0019] The above-mentioned nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide is used in national defense industry and micro-motor systems.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) Gallium-aluminum-based alloys used in aluminothermic components have the effect of changing the microstructure of aluminum and converting part of the Al-Al interface into an Al-Ga interface, thereby inhibiting the formation of a complete and uniform Al2O3 passivation layer on the surface, which can prevent the aluminum fuel from being oxidized during handling and storage, and can accelerate the participation of aluminum in the reaction, thereby increasing the reactivity of aluminum. On the other hand, the low-melting-point alloy formed by room-temperature liquid metal gallium (melting point is only 29.76°C) and metal aluminum can be melted into a liquid state during heating at a relatively low temperature. The spatial confinement of the three-dimensional porous oxidant during the molten infusion process can effectively inhibit the size of the aluminum fuel and prevent the aggregation of nano-aluminum in the subsequent process.

[0022] (2) Compared with vacuum physical vapor deposition technology, the melt infusion method is conducive to the realization of higher nano-aluminum fuel loading and enhances the contact between reactants; at the same time, it avoids the production of highly reactive nano-aluminum, which usually requires complex instruments and equipment or harsh reaction conditions, and is very suitable for large-scale production.

[0023] (3) Based on the advantages of gallium-aluminum alloy and three-dimensional porous oxidant, the present invention is expected to achieve a nano-composite thermite with rapid and thorough combustion and explosion reaction, long-term storage, simple preparation process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a SEM photograph of the nanocomposite thermite material prepared in Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0026] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0027] Example 1

[0028] (1) 0.5 g of liquid gallium metal was placed in a sealed flask. Under the protection of argon gas, 0.5 g of aluminum foil, which had been polished to remove the surface oxide film, was added to the liquid gallium metal. The sealed flask was then heated to 200°C and kept warm for 5 h to prepare a low melting point (≤300°C) gallium-aluminum alloy.

[0029] (2) 10 ml of 10 wt% monodisperse polystyrene (PS) colloidal microsphere dispersion was filtered and self-assembled into a three-dimensional ordered macroporous colloidal crystal skeleton. The copper precursor copper nitrate was impregnated into the pores of the three-dimensional ordered macroporous colloidal crystal skeleton by a solution impregnation method (the solution contained 30 mmol copper nitrate, 20 mmol citric acid, 6.5 ml ethylene glycol, and 3.5 ml methanol). After calcination at 300°C in an air atmosphere for 8 h, the colloidal template was decomposed and the metal salt was thermally oxidized to obtain the corresponding three-dimensional ordered macroporous CuO oxidant.

[0030] (3) 50 mg of the low melting point gallium aluminum alloy obtained in step (1) and 5 mg of the three-dimensional ordered macroporous CuO oxidant obtained in step (2) were placed in a glove box with an argon atmosphere and mixed and heated. After heating at 200-300° C., the low melting point gallium aluminum alloy was melted into a liquid state and poured into the three-dimensional ordered macroporous CuO oxidant, thereby achieving the composite of the gallium aluminum alloy fuel and the three-dimensional porous oxidant, and obtaining a nano-composite aluminothermic material composed of the gallium aluminum alloy and the three-dimensional porous oxide. The SEM of the material is as follows: Figure 1 shown.

[0031] Example 2

[0032] (1) Place 1 g of liquid gallium metal in a sealed flask. Under the protection of argon, add 0.5 g of aluminum foil that has been polished to remove the surface oxide film into the liquid gallium metal. Then heat the sealed flask to 300°C and keep it warm for 3 h to prepare a low melting point (≤300°C) gallium-aluminum alloy.

[0033] (2) 30 ml of 10 wt% monodisperse polystyrene (PS) colloidal microsphere dispersion was filtered and self-assembled into an ordered three-dimensional colloidal crystal skeleton. The copper precursor copper nitrate was impregnated into the pores of the three-dimensional ordered macroporous colloidal crystal skeleton by a solution impregnation method (the solution contained 10 mmol copper nitrate, 20 mmol citric acid, 6.5 ml ethylene glycol, and 3.5 ml methanol). After calcination at 500°C in an air atmosphere for 7.5 h, the colloidal template was decomposed and the metal salt was thermally oxidized to obtain the corresponding three-dimensional ordered macroporous CuO oxidant.

[0034] (3) 45 mg of the low-melting-point gallium-aluminum alloy obtained in step (1) and 7 mg of the three-dimensional ordered macroporous CuO oxidant obtained in step (2) are placed in a glove box with an argon atmosphere and mixed and heated. After heating at 200-300° C., the low-melting-point gallium-aluminum alloy is melted into a liquid state and poured into the three-dimensional ordered macroporous CuO oxidant, thereby achieving the composite of the gallium-aluminum alloy fuel and the three-dimensional porous oxidant. A nanocomposite thermite material composed of the gallium-aluminum alloy and the three-dimensional porous oxide is obtained.

[0035] Example 3

[0036] (1) 0.5 g of liquid gallium metal was placed in a sealed flask. Under the protection of argon gas, 1 g of aluminum foil, which had been polished to remove the surface oxide film, was added to the liquid gallium metal. The sealed flask was then heated to 200°C and kept warm for 5 h to prepare a low melting point (≤300°C) gallium-aluminum alloy.

[0037] (2) The Cu-Mn alloy foil was immersed in 1 mol / L hydrochloric acid and etched for 24 h to dissolve and remove the active components therein, thereby obtaining a three-dimensional continuous porous copper skeleton with adjustable pore type and size, and then taken out and cleaned with deionized water, and calcined at 400° C. for 1 h in an air atmosphere to oxidize the surface of the three-dimensional continuous porous copper skeleton to form a layer of copper oxide to form a three-dimensional porous CuO oxidant foil;

[0038] (3) Take 50 mg of the low-melting-point gallium-aluminum alloy obtained in step (1) and the three-dimensional porous CuO oxidant foil obtained in step (2) and place them in a glove box with an argon atmosphere. The three-dimensional porous CuO oxidant foil and the low-melting-point gallium-aluminum alloy prepared above are stacked in sequence on a flat heater. After heating at 200-300° C., the low-melting-point gallium-aluminum alloy is melted into a liquid state and poured into the three-dimensional porous CuO oxidant foil, thereby realizing the composite of the gallium-aluminum alloy fuel and the three-dimensional porous oxidant, and obtaining a nano-composite thermite material composed of the gallium-aluminum alloy and the three-dimensional porous oxide.

[0039] Example 4

[0040] (1) 0.5 g of liquid gallium metal was placed in a sealed flask. Under the protection of argon gas, 1 g of aluminum foil, which had been polished to remove the surface oxide film, was added to the liquid gallium metal. The sealed flask was then heated to 200°C and kept warm for 5 h to prepare a low melting point (≤300°C) gallium-aluminum alloy.

[0041] (2) The Cu-Zn alloy foil was immersed in 1 mol / L hydrochloric acid and etched for 24 h to dissolve and remove the active components therein, thereby obtaining a three-dimensional continuous porous copper skeleton with adjustable pore type and size, and then taken out and cleaned with deionized water, and calcined at 400° C. for 1 h in an air atmosphere to oxidize the surface of the three-dimensional continuous porous copper skeleton to form a layer of copper oxide to form a three-dimensional porous CuO oxidant foil;

[0042] (3) Take 50 mg of the low-melting-point gallium-aluminum alloy obtained in step (1) and the three-dimensional porous CuO oxidant foil obtained in step (2) and place them in a glove box with an argon atmosphere. The three-dimensional porous CuO oxidant foil and the low-melting-point gallium-aluminum alloy prepared above are stacked in sequence on a flat heater. After heating at 200-300° C., the low-melting-point gallium-aluminum alloy is melted into a liquid state and poured into the three-dimensional porous CuO oxidant, thereby realizing the composite of the gallium-aluminum alloy fuel and the three-dimensional porous oxidant, and obtaining a nano-composite thermite material composed of the gallium-aluminum alloy and the three-dimensional porous oxide.

[0043] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide, Features The steps include: (1) placing liquid metal gallium in a sealed container, adding a metal aluminum foil that has been polished to remove the surface oxide film into the liquid metal gallium under the protection of an inert atmosphere, and then heating the aluminum foil to react to prepare a low-melting-point gallium-aluminum alloy; the mass ratio of gallium to aluminum in the low-melting-point gallium-aluminum alloy is in the range of 1:2 to 2:1; (2) Preparation of three-dimensional ordered macroporous oxides by colloidal crystal template method: a monodisperse polymer colloidal microsphere dispersion is self-assembled into a three-dimensional ordered macroporous colloidal crystal skeleton by vacuum filtration, and then a metal salt is impregnated and filled into the pores of the three-dimensional ordered macroporous colloidal crystal skeleton by a solution impregnation method, and after calcination at 300-500° C. for 5-10 h in an air atmosphere, the colloidal template is decomposed and the metal salt is pyrolyzed and oxidized, thereby obtaining the corresponding three-dimensional ordered macroporous oxide; the metal salt is a copper salt, a zinc salt or a cobalt salt; (3) Preparation of three-dimensional porous oxide foil by dealloying method: using copper alloy foil or molybdenum alloy foil as template, the copper alloy foil is an alloy of at least one of the active components Zn, Mn and Mg with copper, and the molybdenum alloy foil is an alloy of at least one of the active components Zn, Mn and Mg with molybdenum; The copper alloy foil or molybdenum alloy foil is immersed in a dilute acid solution for 12-24 hours to dissolve and remove the active components therein, thereby obtaining a three-dimensional continuous porous copper or molybdenum skeleton with adjustable pore type and size, and then the surface of the three-dimensional continuous porous copper or molybdenum skeleton is oxidized to form a layer of copper oxide or molybdenum trioxide to form a three-dimensional porous oxide foil by heat treatment at 300-500° C. for 1-5 hours in an air atmosphere; (4) mixing and heating the low-melting-point gallium-aluminum alloy obtained in step (1) and the three-dimensional ordered macroporous oxide obtained in step (2) in an argon atmosphere, and subjecting the low-melting-point gallium-aluminum alloy to heat treatment at 200-300° C. to melt the low-melting-point gallium-aluminum alloy into a liquid state, and then pouring the liquid into the three-dimensional ordered macroporous oxide obtained in step (2), thereby achieving the composite of the gallium-aluminum alloy fuel and the three-dimensional ordered macroporous oxide, and obtaining a nanocomposite thermite composed of the gallium-aluminum alloy and the three-dimensional porous oxide; (5) The three-dimensional porous oxide foil obtained in step (3) and the low-melting-point gallium-aluminum alloy obtained in step (1) are sequentially stacked on a flat heater, and the low-melting-point gallium-aluminum alloy is melted into a liquid state after heating at 200-300° C., and then poured into the three-dimensional porous oxide foil, thereby realizing the composite of gallium-aluminum alloy fuel and the three-dimensional porous oxide foil, and obtaining a nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide.

2. A method for preparing a nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 1, Features: The inert gas in step (1) is argon; the temperature range of the heating reaction is 200-300°C, and the time range is 3-5h.

3. The method for preparing a nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 1, Features: The melting point of the low melting point gallium aluminum alloy in step (1) is ≤300°C.

4. The method for preparing a nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 1, Features: The monodisperse polymer colloidal microspheres in step (2) are monodisperse polystyrene colloidal microspheres or polymethyl methacrylate microspheres; the solid content of the monodisperse polymer colloidal microsphere dispersion is 10wt%; the volume range of the monodisperse polymer colloidal microsphere dispersion is 10-60ml; the size of the monodisperse polymer colloidal microspheres is 50-500nm.

5. The method for preparing a nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 1, Features: The solution impregnation method in step (2) is to prepare the metal salt into a metal salt solution with a concentration of 0.05-0.2 mol / L for impregnation.

6. The method for preparing a nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 1, Features: The dilute acid solution in step (3) is 0.5-1 mol / L hydrochloric acid.

7. A nanocomposite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide prepared by the preparation method according to any one of claims 1 to 6.

8. Application of the nano-composite thermite composed of gallium-aluminum alloy and three-dimensional porous oxide according to claim 7 in national defense industry and micro-motor systems.

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