Preparation method of core-shell structure nickel-aluminum-boron composite fuel

Abstract

The application discloses a preparation method of a core-shell structure nickel-aluminum-boron composite fuel, and comprises the following steps: S1, target material treatment: selecting a target material with a proper size, polishing the target material before use, then performing ultrasonic cleaning on the target material with anhydrous ethanol and acetone for 10 minutes, and placing the target material into a sputtering chamber after drying; S2, powder laying: grinding boron powder, and then uniformly laying the boron powder on a glass substrate with a proper size; S3, vacuumizing and pretreating a reaction chamber; S4, sputtering coating; and S5, detecting the modified amorphous boron coated with aluminum. The method is simple, controllable, safe, low in cost and suitable for industrialized scale production. The composite boron powder obtained by the method has an amorphous boron powder as a core and a nickel-aluminum coating layer, has a short ignition delay time, is high in combustion efficiency, and can be directly used as a boron-based energetic material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of boron powder modification, and particularly relates to a core-shell structure amorphous boron functionalized metal coating modification preparation technology. BACKGROUND

[0002] With the continuous progress of aerospace technology and advanced national defense technology, the performance requirements of energetic materials are continuously improved. Adding metal powder to traditional organic energetic materials not only increases the density of the energetic materials, but also further improves the heat value. Compared with common metal fuels, boron has a higher mass heat value (58.9 kJ / g) and volume heat value (137.8 kJ / cm3), which is significantly higher than the heat values of magnesium and aluminum, and has a broad application prospect in the field of solid rocket ramjet engines and mixed explosives.

[0003] The most commonly used boron material in industry is amorphous boron. Amorphous boron has a very high melting point (2177℃) and boiling point (3658℃), and an initial oxidation layer exists on the surface, which makes ignition very difficult. At the same time, due to the large oxygen consumption during combustion, and the low melting point (475℃) and high boiling point (2043℃) of the oxidation product B2O3, a layer of liquid boron oxide is formed on the surface of the boron particles during the combustion process, which hinders the diffusion of external oxygen, resulting in very low combustion efficiency of boron powder and affecting its oxidation heat release capacity.

[0004] At present, boron powder is mainly modified by doping with active metals. However, due to the coral-like shape of amorphous boron powder at room temperature and its easy agglomeration, the simple doping of metal particles often makes it difficult to uniformly disperse in boron powder, and therefore an effective and uniform modification technology for boron powder is in urgent need. SUMMARY

[0005] The purpose of the present application is to solve the problem of the formation of a liquid oxidation film on the surface of boron which hinders the ignition and combustion process of boron, and the problem of the difficulty of uniform dispersion of active metal in boron powder which affects the activation effect by using active metal doping method, and to design and prepare a core-shell structure nickel-aluminum-boron composite fuel in order to achieve efficient and uniform activation modification of amorphous boron.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of a core-shell structure nickel-aluminum-boron composite fuel, comprising the following steps:

[0008] S1, target material treatment:

[0009] Select a target material of appropriate size, polish it before use, then ultrasonically clean it with anhydrous ethanol and acetone for 10 minutes, and then put it into a sputtering chamber after drying;

[0010] S2, powder laying:

[0011] The boron powder is ground finely and then evenly laid on a glass substrate of appropriate size;

[0012] S3, vacuumizing the reaction chamber and pretreating:

[0013] The glass substrate is put into the reaction chamber, the sputtering chamber is vacuumized to 8.6*10 -4 Pa, and then argon is introduced to pre-sputter for 10 min to clean the surface of the substrate and thin the oxide film on the surface of the boron powder;

[0014] S4, sputtering coating:

[0015] According to the thickness of the coating layer, appropriate sputtering power, sputtering pressure, target-substrate distance, gas flow, deposition rate, etc. are selected for sputtering to coat a layer of uniform aluminum on the surface of the boron powder, and then coat a layer of uniform nickel to prepare a core-shell structure nickel-aluminum-boron composite powder;

[0016] S5, detection of the metal aluminum coated amorphous boron.

[0017] As a further improved scheme of the technical solution, in S1, the appropriate size of the target material is selected, specifically: the target material is an aluminum target and a nickel target with a thickness of 5 mm and a diameter of 60 mm.

[0018] As a further improved scheme of the technical solution, in S1, the appropriate size of the target material is selected, specifically: the target material is an aluminum target and a nickel target with a thickness of 20 mm and a diameter of 60 mm.

[0019] As a further improved scheme of the technical solution, in S2, the boron powder is ground finely and then evenly laid on a glass substrate of appropriate size, specifically: the boron powder is ground finely and then evenly laid on a glass substrate with a thickness of 2 mm and a diameter of 30 mm.

[0020] As a further improved scheme of the technical solution, in S4, according to the thickness of the coating layer, appropriate sputtering power, sputtering pressure, target-substrate distance, gas flow, deposition rate, etc. are selected for sputtering to coat a layer of uniform aluminum on the surface of the boron powder, and then coat a layer of uniform nickel to prepare a core-shell structure nickel-aluminum-boron composite powder, specifically:

[0021] Adjust the distance between the aluminum target and the substrate to 48mm, the argon flow rate is 40sccm, the sputtering temperature is room temperature, the sputtering power is set to 200W, the sputtering pressure is 1.6Pa, the discharge voltage is 500V, and the deposition time is 20 minutes, so as to coat a layer of aluminum on the surface of the boron powder to form a thin layer of aluminum-coated modified amorphous boron; on this basis, the distance between the nickel target and the substrate is adjusted to 50mm, the argon flow rate is 40sccm, the sputtering temperature is room temperature, the sputtering power is set to 300W, the sputtering pressure is 2.0Pa, the discharge voltage is 500V, and the deposition time is 15 minutes, so as to coat a layer of nickel on the surface of the aluminum-boron powder to form a thin layer of nickel-aluminum-coated modified amorphous boron.

[0022] As a further improved scheme of the technical solution, in S4, according to the thickness of the coating layer, a suitable sputtering power, sputtering pressure, target-substrate distance, gas flow rate, deposition rate and the like are selected for sputtering, so as to coat a layer of uniform aluminum on the surface of the boron powder and coat a layer of uniform nickel thereon to prepare a core-shell structure nickel-aluminum-boron composite powder, and specifically:

[0023] The distance between the target and the substrate is adjusted to 48mm, the argon flow rate is 40sccm, the sputtering temperature is room temperature, the sputtering power is set to 200W, the sputtering pressure is 1.6Pa, the discharge voltage is 500V, and the deposition time is 120 minutes, so as to coat a thick aluminum coating layer on the surface of the boron powder; on this basis, the distance between the nickel target and the substrate is adjusted to 50mm, the argon flow rate is 40sccm, the sputtering temperature is room temperature, the sputtering power is set to 300W, the sputtering pressure is 2.0Pa, the discharge voltage is 500V, and the deposition time is 60 minutes, so as to coat a layer of nickel on the surface of the aluminum-boron powder to form a thick layer of nickel-aluminum-coated modified amorphous boron.

[0024] As a further improved scheme of the technical solution, in S5, the detection of the modified amorphous boron coated with metal aluminum comprises: observing the structure of the modified boron powder by using a scanning electron microscope, and observing the coating of the aluminum on the boron powder by using an energy spectrometer.

[0025] As a further improved scheme of the technical solution, in S5, the detection of the modified amorphous boron coated with metal aluminum comprises: performing a non-isothermal differential scanning calorimetry test by using a TGA / DSC thermal analyzer to measure the peak temperature in the thermal oxidation process of the studied sample, and obtaining a heat flow curve.

[0026] As a further improved scheme of the technical solution, in S5, the detection of the modified amorphous boron coated with metal aluminum comprises: performing an ignition and combustion experiment by using a laser ignition and combustion online monitoring system, and measuring the ignition delay time of the energetic powder in pure oxygen by using a high-speed camera.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The method is simple, controllable, safe, low in cost and suitable for industrialized scale production, the composite boron powder with amorphous boron powder as a core and nickel-aluminum as a coating layer obtained by the method has short ignition delay time and high combustion efficiency, and can be directly used as a boron-based energetic material.

[0029] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and the content of the specification can be implemented, the following is a preferred embodiment of the present application and the detailed description of the drawings. The specific embodiments of the present application are given in detail by the following examples and their drawings. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application, the schematic embodiments of the present application and their description are used to explain the present application, and do not constitute undue limitation on the present application. In the drawings:

[0031] Figure 1 A preparation method of a core-shell structure nickel-aluminum-boron composite fuel is provided. DETAILED DESCRIPTION

[0032] The magnetron sputtering method is to make argon atoms ionize to produce Ar positive ions and new electrons under the ionization effect of electrons under the action of electric field, the new electrons fly to the substrate, the Ar ions accelerate to the cathode target, and hit the target surface with high energy, so that the target material is sputtered, thereby forming a thin film on the substrate material. This method has the advantages of simple equipment, easy control, large plating area and strong adhesion, and is widely used in the preparation of high-performance thin films.

[0033] Aluminum is a good active metal, which has a good promoting effect on the ignition and combustion of boron powder. However, aluminum is easily oxidized in air, and the coating of aluminum on boron is easy to form an oxide layer, which needs to be effectively inhibited. Nickel has good corrosion resistance, and the addition of a nickel layer outside the aluminum layer can effectively improve the oxidation resistance of the material. In addition, nickel also has combustion heat value and catalytic performance, which contributes to the heat value of the composite material.

[0034] The present application is proposed in this background, a layer of metal aluminum film is sputtered on the surface of amorphous boron by magnetron sputtering, and a layer of nickel is sputtered outside the aluminum film to prevent oxidation, forming a core-shell structure with amorphous boron as the core and metal nickel-aluminum as the coating layer. Combining the combustion heat release performance of aluminum and the oxidation resistance characteristics, heat value contribution and catalytic performance of nickel, the composite functional modification of amorphous boron is realized.

[0035] Example 1

[0036] Preparation of thin-layer nickel-aluminum coated modified amorphous boron

[0037] 1. Preparation of target material

[0038] The target material is aluminum and nickel targets with a thickness of 5 mm and a diameter of 60 mm. Before use, the targets are polished to thin the oxide film on the surface, and then ultrasonically cleaned with anhydrous ethanol and acetone for 10 minutes. After drying, they are placed in the sputtering chamber.

[0039] 2 Powder laying

[0040] The boron powder is ground as finely as possible so that there are no visible agglomerates, and then it is uniformly laid on a glass substrate with a thickness of 2 mm and a diameter of 30 mm. The powder layer is laid as thin as possible to ensure that the powder can be completely sputtered.

[0041] 3 Vacuum pumping and pretreatment of the reaction chamber

[0042] The glass substrate is placed in the reaction chamber, the sputtering chamber is vacuum pumped to 8.6 x 10-4 Pa, and then argon is introduced to pre-sputter for 10 minutes to clean the surface of the substrate and thin the oxide film on the surface of the boron powder.

[0043] 4 Sputter coating

[0044] The distance between the aluminum target and the substrate is adjusted to 48 mm, the argon flow rate is 40 seem, the sputtering temperature is room temperature, the sputtering power is set to 200 W, the sputtering pressure is 1.6 Pa, the discharge voltage is 500 V, and the deposition time is 20 minutes. A layer of aluminum is coated on the surface of the boron powder to form a thin layer of aluminum-coated modified amorphous boron. On this basis, the distance between the nickel target and the substrate is adjusted to 50 mm, the argon flow rate is 40 seem, the sputtering temperature is room temperature, the sputtering power is set to 300 W, the sputtering pressure is 2.0 Pa, the discharge voltage is 500 V, and the deposition time is 15 minutes. A layer of nickel is coated on the surface of the aluminum-boron powder to form a thin layer of nickel-aluminum-coated modified amorphous boron.

[0045] 5. Detection of thin layer nickel-aluminum coated modified amorphous boron

[0046] The structure of the modified boron powder is observed by scanning electron microscopy, the distribution of aluminum and boron is observed by energy dispersive spectroscopy, and the peak temperature during the thermal oxidation process of the studied sample is measured by non-isothermal differential scanning calorimetry (DSC) testing using a TGA / DSC thermal analyzer to obtain the heat flow curve. The ignition and combustion experiment is carried out using a laser ignition and combustion online monitoring system, and the ignition delay time of the energetic powder in pure oxygen is measured by a high-speed camera.

[0047] Example 2

[0048] Preparation of thick layer nickel-aluminum coated modified amorphous boron

[0049] 1 Target preparation

[0050] The target material is aluminum target and nickel target with thickness of 20 mm and diameter of 60 mm. Before use, the target material is polished to thin the oxide film on the surface, and then is cleaned by ultrasonic cleaning with anhydrous ethanol and acetone for 10 minutes. After drying, the target material is placed in the sputtering chamber.

[0051] 2 Powder laying

[0052] The boron powder is ground as finely as possible so that no agglomerates are visible to the naked eye, and then is uniformly laid on a glass substrate with thickness of 2 mm and diameter of 30 mm. The powder layer is laid as thin as possible to ensure that the powder can be sputtered completely.

[0053] 3 Vacuumizing and pretreatment of the reaction chamber

[0054] The glass substrate is placed in the reaction chamber, the sputtering chamber is vacuumized to 8.6 x 10-4 Pa, and then is pre-sputtered for 10 minutes by introducing argon to clean the surface of the substrate and thin the oxide film on the surface of the boron powder.

[0055] 4 Sputtering coating

[0056] The distance between the target material and the substrate is adjusted to 48 mm, the argon flow is 40 sccm, the sputtering temperature is room temperature, the sputtering power is set to 200 W, the sputtering pressure is 1.6 Pa, the discharge voltage is 500 V, and the deposition time is 120 minutes, so that a thick aluminum coating layer is coated on the surface of the boron powder. On this basis, the distance between the nickel target material and the substrate is adjusted to 50 mm, the argon flow is 40 sccm, the sputtering temperature is room temperature, the sputtering power is set to 300 W, the sputtering pressure is 2.0 Pa, the discharge voltage is 500 V, and the deposition time is 60 minutes, so that a nickel coating layer is coated on the surface of the aluminum boron powder, forming a thick nickel aluminum coated modified amorphous boron.

[0057] 5 Detection of the thick nickel aluminum coated modified amorphous boron The structure of the modified boron powder is observed by scanning electron microscopy, the distribution of aluminum and boron is observed by energy dispersive spectrometer, and the peak temperature in the thermal oxidation process of the studied sample is measured by non-isothermal differential scanning calorimetry (DSC) test using TGA / DSC thermal analyzer to obtain the heat flow curve. The ignition and combustion experiment is carried out by using the laser ignition and combustion online monitoring system, and the ignition delay time of the energetic powder in pure oxygen is measured by using the high-speed camera.

[0058] The ignition and combustion experiment is carried out by using the laser ignition and combustion online monitoring system for the pure boron powder and the boron powder of Example 1-2, and the ignition delay time of the energetic powder in pure oxygen is measured by using the high-speed camera. Table 1 shows the results.

[0059] Table 1

[0060] Fuel Ignition delay time Pure boron powder 52 ms Example 1 32.4 ms Example 2 35.6 ms

[0061] As shown in Table 1, the ignition delay time of pure boron powder is 52 ms, the ignition delay time of Example 1 is 32.4 ms, and the ignition delay time of Example 2 is 35.6 ms. Compared with the prior art, the thin-layer nickel-aluminum coated modified amorphous boron fuel and the thick-layer nickel-aluminum coated modified amorphous boron fuel prepared by the present application have the advantage of better ignition performance.

[0062] The above description is only the preferred embodiment of the present application, and does not limit the present application in any form; any person skilled in the art can easily implement the present application according to the drawings and the above description; however, any equivalent changes, modifications and evolutions made by the skilled person in the art within the scope of the technical solutions of the present application, using the above disclosed technical content, are equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments according to the essential technology of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. A method for preparing a core-shell structured nickel-aluminum-boron composite fuel, characterized in that, Includes the following steps: S1, Target material treatment: Select a target of appropriate size, polish it before use, then ultrasonically clean it with anhydrous ethanol and acetone for 10 minutes, dry it and put it into the sputtering chamber. S2, Powder Laying: The boron powder is ground into a fine powder and then evenly spread on a glass substrate of appropriate size. S3, Vacuuming and pretreatment of the reaction chamber: The glass substrate was placed in the reaction chamber, and the vacuum inside the sputtering chamber was evacuated to 8.6 × 10⁻⁶. -4 Pa, then argon gas is introduced for pre-sputtering for 10 min to clean the substrate surface in order to reduce the oxide film on the boron powder surface; S4, Sputtering Coverage: Depending on the required coating thickness, appropriate sputtering power, sputtering pressure, target-substrate distance, gas flow rate, and deposition rate are selected for sputtering. A uniform layer of aluminum is coated on the surface of boron powder, followed by a uniform layer of nickel, to prepare a core-shell structured nickel-aluminum-boron composite powder. S5, Detection of aluminum-coated modified amorphous boron.

2. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, In S1, a target of appropriate size is selected, specifically: the target is an aluminum target with a thickness of 5mm and a diameter of 60mm, and a nickel target.

3. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, In step S1, a target of appropriate size is selected, specifically: the target is an aluminum target with a thickness of 20mm and a diameter of 60mm, and a nickel target.

4. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, In step S2, the boron powder is ground into a fine powder and then evenly spread on a glass substrate of a suitable size. Specifically, the boron powder is ground into a fine powder and then evenly spread on a glass substrate with a thickness of 2 mm and a diameter of 30 mm.

5. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, In step S4, depending on the required coating thickness, appropriate sputtering power, sputtering pressure, target-substrate distance, gas flow rate, and deposition rate are selected for sputtering. A uniform layer of aluminum is coated onto the surface of the boron powder, followed by a uniform layer of nickel, to prepare a core-shell structured nickel-aluminum-boron composite powder. Specifically: The distance between the aluminum target and the substrate was adjusted to 48 mm, the argon flow rate to 40 sccm, the sputtering temperature to room temperature, the sputtering power to 200 W, the sputtering pressure to 1.6 Pa, the discharge voltage to 500 V, and the deposition time to 20 minutes. A layer of aluminum was coated on the surface of the boron powder to form a thin layer of aluminum-coated modified amorphous boron. Based on this, the distance between the nickel target and the substrate was adjusted to 50 mm, the argon flow rate to 40 sccm, the sputtering temperature to room temperature, the sputtering power to 300 W, the sputtering pressure to 2.0 Pa, the discharge voltage to 500 V, and the deposition time to 15 minutes. A layer of nickel was then coated on the surface of the aluminum-boron powder to form a thin layer of nickel-aluminum-coated modified amorphous boron.

6. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, In step S4, depending on the required coating thickness, appropriate sputtering power, sputtering pressure, target-substrate distance, gas flow rate, and deposition rate are selected for sputtering. A uniform layer of aluminum is coated onto the surface of the boron powder, followed by a uniform layer of nickel, to prepare a core-shell structured nickel-aluminum-boron composite powder. Specifically: The target-substrate distance was adjusted to 48 mm, the argon flow rate to 40 sccm, the sputtering temperature to room temperature, the sputtering power to 200 W, the sputtering pressure to 1.6 Pa, the discharge voltage to 500 V, and the deposition time to 120 minutes. A thick aluminum coating layer was then applied to the boron powder surface. Based on this, the target-substrate distance was adjusted to 50 mm, the argon flow rate to 40 sccm, the sputtering temperature to room temperature, the sputtering power to 300 W, the sputtering pressure to 2.0 Pa, the discharge voltage to 500 V, and the deposition time to 60 minutes. A nickel layer was then applied to the aluminum-boron powder surface to form a thick nickel-aluminum coated modified amorphous boron.

7. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, The detection of aluminum-coated modified amorphous boron in step S5 includes: observing the structure of the modified boron powder using a scanning electron microscope and observing the coating of the boron powder by an energy dispersive spectroscopy (EDS) instrument.

8. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, The detection of aluminum-coated modified amorphous boron in step S5 includes: using a TGA / DSC thermal analyzer to perform non-differential scanning calorimetry to measure the peak temperature during the thermal oxidation process of the sample under study and obtain the heat flow curve.

9. The method for preparing a core-shell structured nickel-aluminum-boron composite fuel according to claim 1, characterized in that, The detection of aluminum-coated modified amorphous boron in step S5 includes: conducting an ignition and combustion experiment using a laser ignition and combustion online monitoring system, and measuring the ignition delay time of energetic powder in pure oxygen using a high-speed camera.

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