Single-element w-coated oxide-supported boron fuel and method of making

Abstract

The application provides a single W coated oxide loaded boron fuel and a preparation method. The oxide loaded boron fuel is Bi2O3 / B or V2O5 / B. The surface layer of the single W coated oxide loaded boron fuel is a single W film. The inner layer is B. The middle layer between the W film and B is Bi2O3 particles or V2O5 particles. The application adopts an atomic layer deposition method to deposit a single metal W film on the surface of Bi2O3 / B and V2O5 / B to anchor the Bi2O3 and V2O5 particles, and to prevent the agglomeration and growth of the Bi2O3 and V2O5 particles at high temperatures. The deposition of W in the application makes the ignition of the composite fuel easier, and can increase the heat release of the composite fuel. The preparation method adopted in the application has high control precision, is easy to realize industrialization, and shows a good application prospect in the field of high-energy solid fuel modification.

Description

Technical Field

[0001] This invention belongs to the field of high-energy fuel technology, and relates to boron fuel, specifically to a boron fuel with elemental W coated with supported oxides and its preparation method. Background Technology

[0002] High energy density and high energy release efficiency are key goals in the development of high-energy materials. Adding substances with high catalytic activity and high calorific value has become a common method to improve the energy output of energetic materials. Mg powder and Al powder are the most commonly used high-calorific-value metallic fuels in high-energy materials. Boron fuel has a high calorific value, with a theoretical calorific value of 58.7 kJ / kg, which is 2.3 times that of Al powder and 1.9 times that of Mg powder. The volumetric calorific value of boron is 135.2 kJ / cm³. 3 Its volumetric calorific value is 3.1 times that of Al powder and 1.6 times that of Mg powder, making boron an ideal fuel with great application potential.

[0003] Boron-based rich fuel propellants have high energy release and show great promise for application in powder ramjet engines. However, boron is difficult to ignite and burn. Due to the low melting point and high boiling point of B2O3 on the surface of boron particles, a glassy layer of B2O3 forms on the surface of the boron particles during combustion. This glassy layer covers the surface of the boron, blocking the entry of oxygen and thus reducing the combustion efficiency of boron. Researchers have conducted many theoretical and experimental studies to promote the ignition and combustion of boron fuels. One method is to add oxides or high-calorific-value metals to improve its combustion efficiency. The important mechanism by which metal oxides (such as Bi2O3, CuO, Fe2O3, Al2O3) improve the combustion efficiency and performance of boron particles is their catalytic effect. Bismuth oxide and vanadium oxide have excellent effects in catalyzing the combustion of boron particles. According to literature reports, the addition of bismuth oxide can significantly reduce the oxidation exothermic peak temperature of boron particles and significantly shorten the ignition delay time of boron particles. However, bismuth oxide and vanadium oxide tend to have weak interactions with boron particles during deposition, making them prone to detachment from the boron particles. In catalytic combustion reactions, bismuth oxide and vanadium oxide tend to aggregate and grow, thus severely affecting their catalytic performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a boron fuel with elemental W coated with supported oxides and a preparation method thereof, thereby solving the technical problems of easy agglomeration and detachment of boron-based composite fuels in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A boron fuel with elemental W coated with a supported oxide, wherein the boron fuel with supported oxide is Bi2O3 / B or V2O5 / B, wherein the surface layer of the boron fuel with elemental W coated with supported oxide is an elemental W film, the inner layer is B, and the space between the W film and B is Bi2O3 particles or V2O5 particles; wherein the boron fuel with W coated with supported oxide is (Bi2O3 / B)@W or (V2O5 / B)@W.

[0007] The present invention also has the following technical features:

[0008] The thickness of the elemental W film is 2-10 nm; the mass percentage of elemental W in the boron fuel coated with elemental W and loaded with oxide is 3%-8%.

[0009] The Bi₂O₃ and V₂O₅ particles are both spherical or hemispherical, with a particle size of 1–20 nm. The mass percentage of the Bi₂O₃ or V₂O₅ particles in the fuel does not exceed 4%.

[0010] The oxidation exothermic peak temperature of (Bi2O3 / B)@W is 23℃ earlier than that of Bi2O3 / B; the oxidation exothermic peak temperature of (V2O5 / B)@W is 25℃ earlier than that of V2O5 / B.

[0011] The ignition delay time of (Bi2O3 / B)@W is shortened by 18ms compared to Bi2O3 / B; the ignition delay time of (V2O5 / B)@W is shortened by 16ms compared to V2O5 / B.

[0012] The calorific value of (Bi2O3 / B)@W is increased by 3.2 kJ / g compared to Bi2O3 / B; the calorific value of (V2O5 / B)@W is increased by 1.4 kJ / g compared to V2O5 / B.

[0013] The present invention also protects a method for preparing boron fuel with elemental W coated with supported oxide as described above, characterized in that the method deposits a thin film of elemental W on the surface of Bi2O3 / B or V2O5 / B by atomic layer deposition to prepare boron fuel (Bi2O3 / B)@W or (V2O5 / B)@W with W coated with supported oxide.

[0014] The atomic layer deposition method described herein has a deposition cycle of 3 to 10 times.

[0015] The pressure inside the reaction chamber of the atomic layer deposition method is below 100 Pa, and the temperature inside the reaction chamber is set to 250 °C.

[0016] The method specifically includes the following steps:

[0017] Step 1: Spread Bi2O3 / B or V2O5 / B evenly on the sample stage, then place the sample stage in the reaction chamber of the atomic layer deposition equipment, use a mechanical pump to evacuate the reaction chamber to below 100 Pa, introduce carrier gas at a flow rate of 200 ml / min, and set the temperature in the reaction chamber to 250 °C.

[0018] Step 2: Purge Si2H6 into the precursor storage for 2 seconds; close the carrier gas and the pneumatic valve of the mechanical pump to bring the atomic layer deposition equipment to a quasi-static state; then inject the Si2H6 from the precursor storage into the reaction chamber for 30 seconds to allow the precursor to be saturated and adsorbed on the boron particles. After sufficient adsorption, start the carrier gas purging and open the pneumatic valve of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds.

[0019] Step 3: Purge WF6 into the precursor storage container, close the carrier gas and the pneumatic valve of the mechanical pump to bring the atomic layer deposition equipment to a near-static state, and then inject the precursor from the precursor storage container into the reaction chamber for 30 seconds to allow WF6 to fully react with Si2H6 adsorbed on the boron particles. After the reaction is complete, open the pneumatic valve of the mechanical pump to remove excess precursor or byproducts from the reaction chamber. The purging / pumping time is 120 seconds. The carrier gas is high-purity argon or high-purity nitrogen.

[0020] Step four, steps two and three constitute one cycle of elemental W deposition. This process is repeated for multiple deposition cycles to prepare boron fuels (Bi2O3 / B)@W or (V2O5 / B)@W coated with loaded oxides.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (I) The present invention uses atomic layer deposition to deposit a layer of elemental metal W film on the surface of Bi2O3 / B and V2O5 / B to anchor Bi2O3 and V2O5 particles, and at the same time prevents Bi2O3 and V2O5 particles from agglomerating and growing at high temperature.

[0023] (II) In this invention, the deposition of W makes the composite fuel easier to ignite and can increase the heat release of the composite fuel.

[0024] (III) The preparation method adopted in this invention has high control precision and is easy to industrialize, showing good application prospects in the field of high-energy solid fuel modification. Attached Figure Description

[0025] Figure 1 TEM image of 3.5% Bi2O3 / B.

[0026] Figure 2STEM image of a sample containing 3.5% Bi2O3 / B treated at 400℃.

[0027] Figure 3 TEM image of (3.5% Bi2O3 / B)@W-3cy.

[0028] Figure 4 STEM image of the sample (3.5% Bi2O3 / B)@W-3cy after high-temperature treatment at 400℃.

[0029] Figure 5 XPS spectra of B 1s, Bi 4f, and W 4f for samples such as (3.5% Bi2O3 / B)@W-5cy: where a0 is the B raw material, a1 is 3.5% Bi2O3 / B, and a2 is (3.5% Bi2O3 / B)@W-5cy.

[0030] Figure 6 XPS spectra of samples such as (3.5% V2O5 / B)@W-3cy: where b0 is raw material B, b1 is 3.5% V2O5 / B, and b2 is (3.5% V2O5 / B)@W-3cy.

[0031] Figure 7 DSC data for raw material B, 3.5% Bi2O3 / B, B@W-5cy, and (3.5% Bi2O3 / B)@W-5cy.

[0032] Figure 8 DSC data plots for raw material B, 3.5% V2O5 / B, B@W-3cy, and (3.5% V2O5 / B)@W-3cy.

[0033] Figure 9 The laser ignition delay time data for raw material B, 3.5% Bi2O3 / B, 3.5% V2O5 / B, (3.5% Bi2O3 / B)@W-5cy and (3.5% V2O5 / B)@W-3cy are shown in the figure.

[0034] Figure 10 The graph shows the calorific value test data for 3.5% Bi2O3 / B, 3.5% V2O5 / B, (3.5% Bi2O3 / B)@W-5cy, and (3.5% V2O5 / B)@W-3cy.

[0035] Figure 11 The following is a DSC data graph of raw material B, 3.5% Bi2O3 / B, B@Mo-5cy and (3.5% Bi2O3 / B)@Mo-5cy in Comparative Example 1.

[0036] Figure 12The graph shows the calorific value test data of 3.5% Bi2O3 / B and (3.5% Bi2O3 / B)@Mo-5cy in Comparative Example 1.

[0037] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, all materials and equipment used in this invention are those known in the art. For example, the atomic layer deposition equipment used is a known atomic layer deposition equipment.

[0039] In this invention, boron particles refer to boron powder; the two are the same concept. The boron particles are amorphous boron particles, crystalline boron particles, or a mixture of amorphous and crystalline boron particles; the particle size of the boron particles ranges from micrometers to nanometers.

[0040] In this invention, the Bi2O3 / B used is the Bi2O3 / B and its corresponding preparation method known in the prior art, such as the Bi2O3 / B boron fuel with deposited bismuth oxide and its corresponding preparation method disclosed in Chinese invention patent No. ZL202210462365.0, entitled "A boron fuel with deposited bismuth oxide and its preparation method".

[0041] In this invention, V2O5 / B adopts V2O5 / B and its corresponding preparation method known in the prior art, such as the boron fuel V2O5 / B loaded with vanadium oxide and its corresponding preparation method disclosed in Chinese invention patent No. ZL202210463120.X, entitled "A high energy density boron fuel loaded with vanadium oxide and its preparation method by impregnation".

[0042] Bi2O3 / B and V2O5 / B are two boron-based composite fuels with excellent combustion performance. However, during combustion, Bi2O3 and V2O5 particles are prone to agglomeration and growth. There are also problems such as the loose bonding between Bi2O3 and V2O5 particles and boron particles, which makes them easy to fall off the boron particles. As a result, Bi2O3 and V2O5 do not achieve the best effect in catalyzing the combustion of boron powder.

[0043] Figure 1 The image shows a TEM image of a 3.5% Bi2O3 / B composition. The Bi2O3 particles are spherical and uniform in size, with a particle size of approximately 10 nm. Furthermore, electron microscopy reveals Bi2O3 particles detaching from the boron particles.

[0044] Figure 2 The image shows a STEM image of a sample containing 3.5% Bi2O3 / B treated at 400℃. The Bi2O3 particles aggregated at high temperature, and the aggregation was quite severe.

[0045] Adding elemental metals to boron fuels can overcome the ignition difficulties of boron particles and improve their oxidation combustion efficiency. Adding elemental metal Mo to boron particles can significantly improve the performance of boron fuels. As a metal in the same group as Mo, W has high density and stronger oxidation resistance; therefore, W should also yield good results in improving the combustion performance of boron.

[0046] This invention provides a (Bi2O3 / B)@W and (V2O5 / B)@W fuels and their preparation methods, in which boron is loaded by coating bismuth oxide or vanadium oxide particles with elemental W. The boron particles loaded with bismuth oxide or vanadium oxide are coated with W, which not only anchors the Bi2O3 and V2O5 particles but also prevents the agglomeration and growth of Bi2O3 and V2O5 particles at high temperatures. In addition, elemental W can improve the ignition of boron particles and increase their combustion efficiency.

[0047] The composite fuel prepared by this invention has excellent ignition and combustion performance. The elemental W film can help stabilize Bi2O3 and V2O5 particles, preventing Bi2O3 and V2O5 particles from falling off the B, and can also prevent Bi2O3 and V2O5 particles from agglomerating and growing at high temperatures. At the same time, the elemental metal itself can also burn, which plays an important role in improving the energy release of boron fuel.

[0048] The (Bi2O3 / B)@W and (V2O5 / B)@W fuels prepared by this invention, which are composed of elemental W coated with bismuth oxide or vanadium oxide particles and loaded with boron, have a lower initial oxidation reaction temperature and a significantly shorter ignition delay time compared to the fuel before W deposition, and have very good application prospects.

[0049] In this invention, (Bi2O3 / B)@W refers to the composite material obtained by depositing an elemental W film on Bi2O3 / B using atomic layer deposition technology.

[0050] In this invention, (V2O5 / B)@W refers to a composite material obtained by depositing an elemental W film on a V2O5 / B material using atomic layer deposition technology.

[0051] In this invention, the reaction equation for depositing elemental metal W on the surface of boron particles supported on bismuth oxide or vanadium oxide using atomic layer deposition technology is as follows:

[0052] (1) WF4* + Si2H6 → WSiH2F* + SiHF3 + 1.5H2

[0053] (2) WSiH2F* + 0.5Si2H6 → WSiHFSiH3* + 0.5H2

[0054] (3) WSiHFSiH3* + 2WF6 → WWWF4* + 2SiF4+ 1.5H2+ HF

[0055] In this invention, the deposition of the metal W film advanced the oxidation exothermic peak temperatures of Bi2O3 / B and V2O5 / B by 23°C and 25°C, respectively; shortened the ignition delay times of Bi2O3 / B and V2O5 / B by 18ms and 16ms, respectively; and increased the calorific values ​​of Bi2O3 / B and V2O5 / B by 3.2kJ / g and 1.4kJ / g, respectively.

[0056] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0057] Example 1:

[0058] This embodiment describes a method for preparing boron fuel with elemental W coated with supported oxides, wherein the boron fuel with elemental W coated with supported oxides is (Bi2O3 / B)@W, and the method is carried out by atomic layer deposition.

[0059] This method is performed according to the following steps:

[0060] Step 1: Spread Bi₂O₃ / B evenly on the sample stage, then place the sample stage inside the reaction chamber of the atomic layer deposition (ALD) equipment. Use a mechanical pump to create a negative pressure in the reaction chamber, introduce carrier gas at a flow rate of 200 ml / min, maintain the base pressure of the ALD equipment at approximately 100 Pa, and set the temperature of the reaction chamber to 250 °C. Purge Si₂H₆ into an adjustable precursor memory at a time of 2 seconds. This memory allows for precise control of the amount of precursor introduced.

[0061] Step 2: Close the pneumatic valves of the carrier gas and mechanical pump to bring the system to a quasi-static state. Then, inject Si2H6 from the memory into the reaction chamber for 30 seconds to allow the precursor to be saturated and adsorbed on the boron particles. After sufficient adsorption, start the carrier gas purging and open the pneumatic valve of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds.

[0062] Step 3: Pour WF6 into the adjustable precursor storage container for 2 seconds. This container allows for precise control of the amount of precursor entering the container. Close the pneumatic valves of the carrier gas and mechanical pump to bring the system to a near-static state. Then, inject the precursor from the storage container into the reaction chamber for 30 seconds to allow the elemental metal precursor to fully react with the reducing agent adsorbed on the boron particles. After the reaction is complete, start the carrier gas purging and open the pneumatic valve of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds.

[0063] Step four, steps two and three constitute one cycle of elemental W deposition. Repeating steps 3.1 to 3.3 can control the number of deposition cycles of elemental W on boron particles, resulting in (Bi2O3 / B)@W samples.

[0064] Figure 3 The image shows a TEM image of (3.5% Bi2O3 / B)@W-3cy. After W deposition, the Bi2O3 particles are tightly fixed on the boron particles, and no Bi2O3 particles detached from the boron particles are observed in the electron microscope. The Bi2O3 particles are uniform in size, with a particle size of about 10 nm.

[0065] Figure 4 This is a STEM image of the sample (3.5% Bi₂O₃ / B)@W-3cy after high-temperature treatment at 400℃. The STEM images show that the Bi₂O₃ particles did not aggregate or grow after the high-temperature treatment. This indicates that the deposition of W not only helps boron anchor the Bi₂O₃ particles, preventing them from detaching from the boron particles, but also prevents the aggregation and growth of the Bi₂O₃ particles.

[0066] Figure 5 XPS spectra of B 1s, Bi 4f, and W 4f for samples such as (3.5% Bi2O3 / B)@W-5cy: where a0 is the B raw material, a1 is 3.5% Bi2O3 / B, and a2 is (3.5% Bi2O3 / B)@W-5cy. The binding energy at 187.7 eV in the B1s spectrum is assigned to B. 0 The peak height of 3.5%Bi2O3 / B is lower than that of the B raw material. This is because Bi2O3 is deposited on the B surface, covering part of the B, thus reducing the peak height. The B1s signal of (3.5%Bi2O3 / B)@W-5cy is significantly reduced because the W film deposition covers not only Bi2O3 but also B. The binding energy of Bi 4f at 159.6 eV is attributed to Bi. 3+ The peak value is significantly weakened in Bi 4f because the deposition of the W film covers the exposed Bi 2O 3. In W 4f, 35.7 eV is attributed to W. 6+ 31.4 eV belongs to W 0 The W on the surface underwent partial oxidation. In terms of the degree of oxidation, W has better oxidation resistance than elemental Mo.

[0067] Example 2:

[0068] This embodiment describes a method for preparing boron fuel with elemental W coated with supported oxides, wherein the boron fuel with elemental W coated with supported oxides is (V2O5 / B)@W, and the method is carried out by atomic layer deposition.

[0069] This method is performed according to the following steps:

[0070] Step 1: Spread V₂O₅ / B evenly on the sample stage, then place the sample stage inside the reaction chamber of the atomic layer deposition (ALD) equipment. Use a mechanical pump to create a negative pressure in the reaction chamber, introduce carrier gas at a flow rate of 200 ml / min, maintain the base pressure of the ALD equipment at approximately 100 Pa, and set the temperature of the reaction chamber to 250 °C. Pour Si₂H₆ into an adjustable precursor memory at a time of 2 seconds. This memory allows for precise control of the amount of precursor introduced.

[0071] Step 2: Close the pneumatic valves of the carrier gas and mechanical pump to bring the system to a quasi-static state. Then, inject Si2H6 from the memory into the reaction chamber for 30 seconds to allow the precursor to be saturated and adsorbed on the boron particles. After sufficient adsorption, start the carrier gas purging and open the pneumatic valve of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds.

[0072] Step 3: Pour WF6 into the adjustable precursor storage container for 2 seconds. This container allows for precise control of the amount of precursor entering the container. Close the pneumatic valves of the carrier gas and mechanical pump to bring the system to a near-static state. Then, inject the precursor from the storage container into the reaction chamber for 30 seconds to allow the elemental metal precursor to fully react with the reducing agent adsorbed on the boron particles. After the reaction is complete, start the carrier gas purging and open the pneumatic valve of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds.

[0073] Step four, steps two and three constitute one cycle of elemental W deposition. Repeating steps 3.1 to 3.3 can control the number of deposition cycles of elemental W on boron particles, resulting in (V2O5 / B)@W samples.

[0074] Figure 6 XPS spectra of samples such as (3.5% V₂O₅ / B)@W-3cy, including B 1s, V 2p, and W 4f spectra: where b0 is the B raw material, b1 is 3.5% V₂O₅ / B, and b2 is (3.5% V₂O₅ / B)@W-3cy. The B 1s and W 4f spectra are compared with... Figure 5 The results were similar. The deposition of the W film covered not only V2O5 but also B.

[0075] Example 3:

[0076] This embodiment provides TG-DSC testing of (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels. Specifically, the TG-DSC testing method for (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels includes:

[0077] Weigh the (Bi2O3 / B)@W or (V2O5 / B)@W composite fuel into an alumina crucible, place the crucible on the sample stage of the TG-DSC testing equipment, set the instrument's heating rate to 10K / min, the test temperature range to room temperature - 900℃, and the test atmosphere to air. In this way, the TG and DSC curves of the composite boron fuel can be obtained.

[0078] Figure 7 The figures show DSC data for raw material B, 3.5% Bi₂O₃ / B, B@W-5cy, and (3.5% Bi₂O₃ / B)@W-5cy. The combustion exothermic peak temperature for boron raw material is 660℃, for 3.5% Bi₂O₃ / B it is 546℃, for B@W-5cy it is 553℃, and for (3.5% Bi₂O₃ / B)@W-5cy it is 523℃. Thus, the deposition of the W metal film advanced the oxidation exothermic peak temperature of Bi₂O₃ / B by 23℃.

[0079] Figure 8 The figures show DSC data for raw material B, 3.5% V₂O₅ / B, B@W-3cy, and (3.5% V₂O₅ / B)@W-3cy. The combustion exothermic peak temperature for boron raw material is 660℃, for 3.5% V₂O₅ / B it is 528℃, for B@W-3cy it is 540℃, and for (3.5% V₂O₅ / B)@W-3cy it is 503℃. Thus, the deposition of the W metal film advanced the oxidation exothermic peak temperature of 3.5% V₂O₅ / B by 25℃.

[0080] Example 4:

[0081] This embodiment provides a laser ignition delay time test for (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels. Specifically, (Bi2O3 / B)@W or (V2O5 / B)@W composite fuels are weighed into an alumina crucible, which is then placed in the sample stage of a laser ignition instrument. The instrument parameters are set as follows: frequency (Hz): 1000; duty cycle (1-40%): 3; number of pulses: 1000; pulse train output; power: 40W; pulse energy: 40mJ; pulse width: 30μs.

[0082] Figure 9 The graph shows the laser ignition delay time data for raw material B, 3.5% Bi₂O₃ / B, 3.5% V₂O₅ / B, (3.5% Bi₂O₃ / B)@W-5cy, and (3.5% V₂O₅ / B)@W-3cy. The ignition delay time is 51.8 ms for boron raw material, 49.6 ms for 3.5% Bi₂O₃ / B, 42.5 ms for 3.5% V₂O₅ / B, and 31.9 ms for (3.5% Bi₂O₃ / B)@W-5cy.

[0083] The ignition delay time of (3.5% V2O5 / B)@W-3cy was 26.8 ms. The deposition of the metal W film shortened the ignition delay times of Bi2O3 / B and V2O5 / B by 18 ms and 16 ms, respectively.

[0084] Example 5:

[0085] This embodiment provides a test for the heat of combustion of (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels. Specifically, 100mg-200mg of (Bi2O3 / B)@W or (V2O5 / B)@W composite fuel is weighed into lens paper, and the sample is completely wrapped with the lens paper and placed in the oxygen bomb crucible of the oxygen bomb calorimeter. The sample mass and lens paper mass are entered, and the test begins.

[0086] Figure 10 The graph shows the calorific value test data for 3.5% Bi₂O₃ / B, 3.5% V₂O₅ / B, (3.5% Bi₂O₃ / B)@W-5cy, and (3.5% V₂O₅ / B)@W-3cy. The calorific value of 3.5% Bi₂O₃ / B is 24.2 kJ / g, 3.5% V₂O₅ / B is 25.7 kJ / g, (3.5% Bi₂O₃ / B)@W-5cy is 27.4 kJ / g, and (3.5% V₂O₅ / B)@W-3cy is 27.1 kJ / g. The deposition of the W metal film increased the calorific value of Bi₂O₃ / B and V₂O₅ / B by 3.2 kJ / g and 1.4 kJ / g, respectively.

[0087] Comparative Example 1:

[0088] This comparative example provides a method for preparing boron fuel with elemental Mo coated on supported oxides, wherein the boron fuel with elemental Mo coated on supported oxides is (V2O5 / B)@Mo, and the method is to prepare it by atomic layer deposition.

[0089] This method is essentially the same as that in Examples 1 and 2, except that Mo, belonging to the same group as W, is used in this comparative example to replace W in Example 1, in order to demonstrate the unique effect of W on improving the performance of oxide-loaded boron fuels in this invention. In this comparative example, the precursor WF6 in Examples 1 and 2 is replaced with MoF6.

[0090] In this comparative example, although Mo could be successfully prepared using the same method, the DSC data of the (Bi2O3 / B)@Mo material was almost identical to that of the Bi2O3 / B material before Mo deposition. Figure 11 As shown, Mo cannot significantly reduce the oxidation peak temperature of Bi2O3 / B like W can.

[0091] In addition, such as Figure 12 As shown, the calorific value of (Bi2O3 / B)@Mo material is lower than that of Bi2O3 / B material. This result is consistent with... Figure 10 Conversely, the deposition of a metallic W film increases the calorific value of Bi₂O₃ / B and V₂O₅ / B, while the deposition of Mo actually decreases the calorific value of Bi₂O₃ / B. Therefore, the deposition of Mo has no beneficial effect on the performance of Bi₂O₃ / B materials.

[0092] As can be seen from the above embodiments and comparative examples, compared with the prior art, the (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels prepared by the present invention have advantages such as good repeatability, environmental friendliness, and high ignition and combustion performance. The preparation process of this type of composite fuel with metallic elemental deposition on the surface of boron particles is simple and convenient. The atomic layer deposition technique used in this experimental method has mild conditions, and the experimental reagents are all commonly used in laboratories. The sample preparation cost is low. The (Bi2O3 / B)@W and (V2O5 / B)@W composite fuels of the present invention are easy to prepare, have good repeatability, and are inexpensive, greatly reducing the preparation cost of boron particle-based fuels and showing great application prospects.

Claims

1. A boron fuel with elemental W coated with a supported oxide, wherein the supported oxide boron fuel is Bi₂O₃ / B or V₂O₅ / B, characterized in that, The boron fuel with elemental W coated with supported oxide has an elemental W film on the surface and B on the inner layer, with Bi2O3 particles or V2O5 particles in between the W film and B; the boron fuel with W coated with supported oxide is (Bi2O3 / B)@W or (V2O5 / B)@W. The mass percentage of elemental W in the boron fuel coated with oxide is 3% to 8%.

2. The boron fuel with elemental W coated with supported oxides as described in claim 1, characterized in that, The thickness of the elemental W film is 2–10 nm.

3. The boron fuel with elemental W coated with supported oxides as described in claim 1, characterized in that, The Bi2O3 particles and V2O5 particles are both spherical or hemispherical, with a particle size of 1-20 nm; the mass percentage of the Bi2O3 particles or V2O5 particles in the fuel does not exceed 4%.

4. The boron fuel with elemental W coated with supported oxides as described in claim 1, characterized in that, The oxidation exothermic peak temperature of (Bi2O3 / B)@W is 23℃ earlier than that of Bi2O3 / B; the oxidation exothermic peak temperature of (V2O5 / B)@W is 25℃ earlier than that of V2O5 / B.

5. The boron fuel with elemental W coated with supported oxides as described in claim 1, characterized in that, The ignition delay time of (Bi2O3 / B)@W is shortened by 18ms compared to Bi2O3 / B; the ignition delay time of (V2O5 / B)@W is shortened by 16ms compared to V2O5 / B.

6. The boron fuel with elemental W coated with supported oxides as described in claim 1, characterized in that, The calorific value of (Bi2O3 / B)@W is increased by 3.2 kJ / g compared to Bi2O3 / B; the calorific value of (V2O5 / B)@W is increased by 1.4 kJ / g compared to V2O5 / B.

7. A method for preparing boron fuel with elemental W coated with supported oxide as described in any one of claims 1 to 6, characterized in that, This method involves depositing a thin film of elemental W on the surface of Bi2O3 / B or V2O5 / B using atomic layer deposition to prepare boron fuels (Bi2O3 / B)@W or (V2O5 / B)@W coated with supported oxides.

8. The method for preparing boron fuel with elemental W coated with supported oxide as described in claim 7, characterized in that, The atomic layer deposition method described herein has a deposition cycle of 3 to 10 times.

9. The method for preparing boron fuel with elemental W coated with supported oxide as described in claim 7, characterized in that, The pressure inside the reaction chamber of the atomic layer deposition method is below 100 Pa, and the temperature inside the reaction chamber is set to 250 °C.

10. The method for preparing boron fuel with elemental W coated with supported oxide as described in claim 7, characterized in that, The method specifically includes the following steps: Step 1: Spread Bi2O3 / B or V2O5 / B evenly on the sample stage, then place the sample stage in the reaction chamber of the atomic layer deposition equipment, use a mechanical pump to evacuate the reaction chamber to below 100 Pa, introduce carrier gas at a flow rate of 200 ml / min, and set the temperature in the reaction chamber to 250 °C. Step 2: Purge Si2H6 into the precursor storage for 2 seconds; close the pneumatic valves of the carrier gas and mechanical pump to bring the atomic layer deposition equipment to a quasi-static state; then inject the Si2H6 from the precursor storage into the reaction chamber for 30 seconds to allow the precursor to be saturated and adsorbed on the boron particles. After sufficient adsorption, turn on the carrier gas to purge and turn on the pneumatic valves of the mechanical pump to remove excess precursor or physically adsorbed precursor from the reaction chamber. The purging / pumping time is 120 seconds. Step 3: Purge WF6 into the precursor storage, close the pneumatic valves of the carrier gas and mechanical pump to bring the atomic layer deposition equipment to a quasi-static state, and then inject the precursor from the precursor storage into the reaction chamber for 30 seconds to allow WF6 to fully react with Si2H6 adsorbed on the boron particles. After the reaction is complete, open the pneumatic valve of the mechanical pump to remove excess precursor or byproducts from the reaction chamber. The purging / pumping time is 120 seconds. The carrier gas is high-purity argon or high-purity nitrogen. Step four, steps two and three constitute one cycle of elemental W deposition. This process is repeated for multiple deposition cycles to prepare boron fuels (Bi2O3 / B)@W or (V2O5 / B)@W coated with loaded oxides.

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