A preparation method of metal-modified aluminum-lithium alloy powder and powder

Abstract

The present invention belongs to the field of metal powder material preparation, and specifically relates to a preparation method and powder of metal modified aluminum-lithium alloy powder. The method comprises: adding a first nickel salt solution with a nickel ion concentration of 0.01 mol / L to 0.05 mol / L to an aluminum-lithium alloy powder dispersion, reacting at a temperature of 30°C to 60°C to obtain a precursor modified powder dispersion, wherein the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.1; the aluminum-lithium alloy powder in the aluminum-lithium alloy powder dispersion is an aluminum-lithium alloy powder that has been subjected to film removal treatment; adding a second nickel salt solution with a nickel ion concentration of 0.1 mol / L to 0.5 mol / L to the precursor modified powder dispersion, reacting at a temperature of 50°C to 80°C to obtain a modified powder dispersion, and after solid-liquid separation, obtaining a modified aluminum-lithium alloy powder, wherein the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01 to 0.1. The modified powder has improved combustion performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal powder material preparation, and in particular, relates to a preparation method of metal-modified aluminum-lithium alloy powder and the powder. Background Art

[0002] Aluminum-lithium alloy powder has good thermal reactivity and has been proposed to be used as a high-energy additive in the fields of explosives, solid propellants, etc. However, due to the addition of lithium, a network structure is formed on the surface of the alloy, which reduces the stability of the alloy powder. Oxygen can easily enter the interior of the powder, causing the metal to be continuously oxidized, reducing the active metal content of the aluminum-lithium alloy powder, and ultimately affecting the combustion performance.

[0003] It has been proposed to provide a coating layer on the surface of aluminum-lithium alloy powder to improve the stability of aluminum-lithium alloy powder. Organic acids, aluminum stearate, polysiloxane, polyethylene glycol, etc. have been used as coating layers for aluminum-lithium alloy powder. However, it was found that although the stability of aluminum-lithium alloy powder was improved, the combustion performance of the powder was limited when used as an energetic additive.

[0004] It should be noted that this part of the present invention only provides background technology related to the present invention and does not necessarily constitute prior art or known technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the defect of limited combustion performance of existing modified aluminum-lithium alloy powder with a coating layer, and to provide a preparation method and powder of metal modified aluminum-lithium alloy powder, wherein the modified powder has significantly improved combustion performance.

[0006] In order to achieve the above objectives, in a first aspect, the present invention provides a method for preparing a metal-modified aluminum-lithium alloy powder, comprising:

[0007] Adding a first nickel salt solution to an aluminum-lithium alloy powder dispersion, stirring and reacting at a first preset temperature to obtain a precursor modified powder dispersion, wherein the first preset temperature is 30° C. to 60° C., the concentration of nickel ions in the first nickel salt solution is 0.01 mol / L to 0.05 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.1; the aluminum-lithium alloy powder in the aluminum-lithium alloy powder dispersion is an aluminum-lithium alloy powder that has been subjected to a film removal treatment, and the film removal treatment refers to the removal of an oxide film and / or a hydroxide film on the surface of the powder;

[0008] A second nickel salt solution is added to the precursor modified powder dispersion, and the reaction is stirred at a second preset temperature to obtain a modified powder dispersion. After solid-liquid separation of the modified powder dispersion, a metal-modified aluminum-lithium alloy powder is obtained. The second preset temperature is 50°C~80°C, the concentration of nickel ions in the second nickel salt solution is 0.1mol / L~0.5mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01~0.1.

[0009] In some preferred embodiments, the first preset temperature is 30°C to 40°C; and / or the second preset temperature is 60°C to 70°C.

[0010] In some preferred embodiments, the concentration of nickel ions in the first nickel salt solution is 0.01 mol / L to 0.03 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.04;

[0011] And / or, the concentration of nickel ions in the second nickel salt solution is 0.2 mol / L-0.4 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.03-0.07.

[0012] In some preferred embodiments, the reaction is stirred at the first preset temperature for 10 min to 60 min, and the reaction is stirred at the second preset temperature for 30 min to 90 min.

[0013] In some preferred embodiments, a dry inert gas is introduced into a dispersion of an initial aluminum-lithium alloy powder and then a weak acid is added to obtain the aluminum-lithium alloy powder dispersion after the reaction. The surface of the initial aluminum-lithium alloy powder has an oxide film and / or a hydroxide film, and the weak acid includes at least one of hydrofluoric acid, acetic acid, and acetic acid.

[0014] In some preferred embodiments, the aluminum-lithium alloy powder that has not been subjected to film removal treatment has an average particle size of 1 μm to 100 μm, a lithium content of 2 wt% to 10 wt%, and an aluminum content of 90 wt% to 98 wt%.

[0015] In some preferred embodiments, the first nickel salt solution and the second nickel salt solution both have SO4 2- , Cl - At least one of them.

[0016] In some preferred embodiments, the solvent of the aluminum-lithium alloy powder dispersion, the solvent of the first nickel salt solution, and the solvent of the second nickel salt solution all include at least one of ethanol, ethylene glycol, and glycerol.

[0017] In a second aspect, the present invention provides a metal-modified aluminum-lithium alloy powder, which is prepared by the preparation method as described in the first aspect, and comprises an aluminum-lithium alloy core and a nickel coating layer coated on the outside of the aluminum-lithium alloy core.

[0018] In some preferred embodiments, the Ni content of the metal-modified aluminum-lithium alloy powder is 1wt%~4wt%, and the calorific value of combustion is 30000J / g~32000J / g.

[0019] The present invention adds a first nickel salt solution to an aluminum-lithium alloy powder dispersion, stirs and reacts at a first preset temperature, reduces the kinetic conditions for the occurrence of a substitution reaction by making the concentration of nickel ions in the first nickel salt solution 0.01 mol / L-0.05 mol / L, the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01-0.1, and the first preset temperature is 30°C-60°C, and can promote the formation of a nickel layer with uniform thickness on the surface of lithium on the surface of the aluminum-lithium alloy powder, adds a second nickel salt solution to a precursor modified powder dispersion, stirs and reacts at a second preset temperature, makes the concentration of nickel ions in the second nickel salt solution 0.1 mol / L-0.5 mol / L, the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01-0.1, and the second preset temperature is 50°C-80°C, and can form a uniform nickel layer on the surface of aluminum on the surface of the aluminum-lithium alloy powder, and can form a nickel layer with uniform thickness on the entire surface of the aluminum-lithium alloy powder through two-step nickel coating under specific conditions. The present invention forms a nickel coating layer on the surface of the aluminum-lithium alloy powder. Compared with other coating layers, firstly, when the aluminum-lithium alloy powder is burned, the nickel layer is easy to react with oxygen to release a large amount of heat, which can improve the combustion effect of the powder. Secondly, during the combustion process, oxygen can easily pass through the nickel layer and penetrate into the interface between the nickel layer and the aluminum-lithium core, and undergo redox reactions with aluminum and lithium active metals, which can promote the full and rapid combustion of aluminum and lithium. Thirdly, the nickel layer is a "bridge" that can transfer oxygen, that is, during the combustion temperature rise process, the nickel layer is oxidized by external oxygen, and the nickel oxide undergoes redox reactions with active aluminum and lithium to generate nickel again. When the active aluminum-lithium core receives enough external oxygen, the thermal reaction quickly diffuses from the highly active Ni-Al interface and Ni-Li interface to the inside, which will eventually cause the coated aluminum-lithium alloy powder to be oxidized in a cracked manner, which can promote the full combustion of the aluminum-lithium alloy powder. Fourthly, nickel can effectively prevent aluminum and lithium from reacting with air at room temperature, thereby improving stability. Through the above multiple effects, the combustion performance of the aluminum-lithium alloy powder, such as the combustion calorific value, can be significantly improved.

[0020] If the present invention only adopts the first step reaction to coat the nickel layer on the surface of the aluminum-lithium alloy powder, the nickel layer cannot be formed on the surface of the aluminum on the surface of the aluminum-lithium alloy powder. The surface of the aluminum on the surface of the aluminum-lithium alloy powder is prone to form aluminum oxide. During the combustion process, oxygen is not easy to pass through the aluminum oxide layer, which affects the full and rapid combustion of the aluminum and lithium. During the combustion temperature rise process, the aluminum oxide cannot play a role in transferring oxygen, which affects the full combustion of the aluminum-lithium alloy powder. If only the conditions of the second step reaction are used, a nickel salt solution is added to the aluminum-lithium alloy powder dispersion, the concentration of nickel ions in the nickel salt solution is 0.1 mol / L~0.5 mol / L, the ratio of the volume of the nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01~0.1, the reaction is stirred at a temperature of 50°C~80°C, and the modified powder is obtained by solid-liquid separation. The reaction kinetic conditions of nickel and aluminum are different from those of nickel and lithium. When the kinetic conditions are high, the molecular motion is intensified, the probability of collision and bonding between the reactants is high, and the size of the generated nano-nickel particles is large. When the kinetic conditions are low, the size of the generated nano-nickel particles is small, which can easily lead to uneven coating of the aluminum core and the lithium core, with a thicker coating layer on the lithium core and a thinner coating layer on the aluminum core. If the coating layer is too thick, the effective content of aluminum and lithium active metals will be reduced, and the fuel efficiency will be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a transmission electron microscope photograph of the modified aluminum-lithium alloy powder of Example 1.

[0023] Figure 2 This is a scanning electron microscope photograph of the modified aluminum-lithium alloy powder of Example 1.

[0024] Figure 3 This is the EDS spectrum of the nickel coating layer of the modified aluminum-lithium alloy powder of Example 1.

[0025] Figure 4 This is the EDS spectrum of the aluminum-lithium alloy core of the modified aluminum-lithium alloy powder of Example 1.

[0026] Figure 5 This is a scanning electron microscope photograph of the modified aluminum-lithium alloy powder of Comparative Example 1.

[0027] Figure 6 This is a scanning electron microscope photograph of the modified aluminum-lithium alloy powder of Comparative Example 2. DETAILED DESCRIPTION

[0028] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0029] The inventors of the present application have found through research that the existing modified aluminum-lithium alloy powder with a coating layer has limited combustion performance.

[0030] In this regard, in a first aspect, the present invention provides a method for preparing a metal-modified aluminum-lithium alloy powder, comprising:

[0031] Adding a first nickel salt solution to an aluminum-lithium alloy powder dispersion, stirring and reacting at a first preset temperature to obtain a precursor modified powder dispersion, wherein the first preset temperature is 30° C. to 60° C., the concentration of nickel ions in the first nickel salt solution is 0.01 mol / L to 0.05 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.1; the aluminum-lithium alloy powder in the aluminum-lithium alloy powder dispersion is an aluminum-lithium alloy powder that has been subjected to a film removal treatment, and the film removal treatment refers to the removal of an oxide film and / or a hydroxide film on the surface of the powder;

[0032] A second nickel salt solution is added to the precursor modified powder dispersion, and the reaction is stirred at a second preset temperature to obtain a modified powder dispersion. After solid-liquid separation of the modified powder dispersion, a metal-modified aluminum-lithium alloy powder is obtained. The second preset temperature is 50°C~80°C, the concentration of nickel ions in the second nickel salt solution is 0.1mol / L~0.5mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01~0.1.

[0033] The present invention adds a first nickel salt solution to an aluminum-lithium alloy powder dispersion, stirs and reacts at a first preset temperature, reduces the kinetic conditions for the occurrence of a substitution reaction by making the concentration of nickel ions in the first nickel salt solution 0.01 mol / L-0.05 mol / L, the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01-0.1, and the first preset temperature is 30°C-60°C, and can promote the formation of a nickel layer with uniform thickness on the surface of lithium on the surface of the aluminum-lithium alloy powder, adds a second nickel salt solution to a precursor modified powder dispersion, stirs and reacts at a second preset temperature, makes the concentration of nickel ions in the second nickel salt solution 0.1 mol / L-0.5 mol / L, the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01-0.1, and the second preset temperature is 50°C-80°C, and can form a uniform nickel layer on the surface of aluminum on the surface of the aluminum-lithium alloy powder, and can form a nickel layer with uniform thickness on the entire surface of the aluminum-lithium alloy powder through two-step nickel coating under specific conditions.

[0034] The present invention forms a nickel coating layer on the surface of the aluminum-lithium alloy powder. Firstly, when the aluminum-lithium alloy powder is burned, the nickel layer is easy to react with oxygen to release a large amount of heat, which can improve the combustion effect of the powder. Secondly, during the combustion process, oxygen can easily pass through the nickel layer and penetrate into the interface between the nickel layer and the aluminum-lithium core, and undergo redox reactions with aluminum and lithium active metals, which can promote the full and rapid combustion of aluminum and lithium. Thirdly, the nickel layer is a "bridge" that can transfer oxygen, that is, during the combustion temperature rise process, the nickel layer is oxidized by external oxygen, and nickel oxide undergoes redox reactions with active aluminum and lithium to generate nickel again. When the active aluminum-lithium core receives enough external oxygen, the thermal reaction quickly diffuses from the highly active Ni-Al interface and Ni-Li interface to the inside, which will eventually cause the coated aluminum-lithium alloy powder to be oxidized in a cracked manner, which can promote the full combustion of the aluminum-lithium alloy powder. Fourthly, nickel can effectively prevent aluminum and lithium from reacting with air at room temperature, thereby improving stability. Through the above multiple effects, the combustion performance of the aluminum-lithium alloy powder, such as the combustion calorific value, can be significantly improved.

[0035] If the present invention only adopts the first step reaction to coat the surface of the aluminum-lithium alloy powder with a nickel layer, the nickel layer cannot be formed on the surface of the aluminum on the surface of the aluminum-lithium alloy powder, and the surface of the aluminum on the surface of the aluminum-lithium alloy powder is easy to form aluminum oxide. During the combustion process, oxygen is not easy to pass through the aluminum oxide layer, which affects the full and rapid combustion of aluminum and lithium. During the combustion temperature rise process, aluminum oxide cannot play a role in transferring oxygen, which affects the full combustion of the aluminum-lithium alloy powder. If only the conditions of the second step reaction are adopted, a nickel salt solution is added to the aluminum-lithium alloy powder dispersion, the concentration of nickel ions in the nickel salt solution is 0.1mol / L~0.5mol / L, the ratio of the volume of the nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01~0.1, the reaction is stirred at a temperature of 50℃~80℃, and the solid-liquid separation is performed to obtain the modified powder, which easily leads to uneven coating of the aluminum core part and the lithium core part, the coating layer of the lithium core part is thicker, and the coating layer of the aluminum core part is thinner, and the coating layer is too thick, which will lead to a decrease in the effective content of aluminum and lithium active metals and a decrease in combustion efficiency. If the temperature of the first step reaction is lower than 30°C, the concentration of nickel ions in the first nickel salt solution is lower than 0.01 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is lower than 0.01, the first step reaction cannot form a uniform coating on the surface of lithium. If the temperature of the second step reaction is higher than 80°C, the concentration of nickel ions in the second nickel salt solution is higher than 0.5 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is higher than 0.1, it is easy to cause the nickel layer on the surface of the aluminum on the surface of the aluminum-lithium alloy powder to be too thick, affecting the combustion efficiency.

[0036] The first preset temperature of the present invention is, for example, 30°C, 40°C, 50°C and 60°C, the concentration of nickel ions in the first nickel salt solution is, for example, 0.01mol / L, 0.02mol / L, 0.03mol / L, 0.04mol / L and 0.05mol / L, the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is, for example, 0.01, 0.03, 0.05, 0.07, 0.09 and 0.1, the second preset temperature is, for example, 50°C, 60°C, 70°C and 80°C, the concentration of nickel ions in the second nickel salt solution is, for example, 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L and 0.5mol / L, the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is, for example, 0.01, 0.03, 0.05, 0.07, 0.09 and 0.1, etc.

[0037] The oxide film and / or hydroxide film of the present invention includes, for example, lithium oxide, aluminum oxide, and lithium hydroxide.

[0038] In some preferred embodiments, the first preset temperature is 30°C~40°C; and / or the second preset temperature is 60°C~70°C, which is more conducive to controlling the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, forming a nickel coating layer of uniform thickness on the entire surface of the aluminum-lithium alloy powder, and improving the combustion properties of the aluminum-lithium alloy powder, such as the combustion calorific value.

[0039] In some preferred embodiments, the concentration of nickel ions in the first nickel salt solution is 0.01mol / L~0.03mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01~0.04; and / or, the concentration of nickel ions in the second nickel salt solution is 0.2mol / L~0.4mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.03~0.07. Under this preferred scheme, it is more conducive to controlling the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, forming a nickel coating layer of uniform thickness on the entire surface of the aluminum-lithium alloy powder, and improving the combustion performance of the aluminum-lithium alloy powder, such as the combustion calorific value.

[0040] In some preferred embodiments, the reaction is stirred at the first preset temperature for 10 min to 60 min, and the reaction is stirred at the second preset temperature for 30 min to 90 min. It is more conducive to the complete formation of a nickel layer on the surface of the lithium on the surface of each aluminum-lithium alloy powder in the first step reaction, and the complete formation of a nickel layer on the surface of the aluminum on the surface of each aluminum-lithium alloy powder in the second step reaction. The reaction time at the first preset temperature of the present invention is, for example, 10 min, 20 min, 30 min, 40 min, 50 min and 60 min, and the reaction time at the second preset temperature is, for example, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min and 90 min, etc.

[0041] The present invention does not limit the method of obtaining the aluminum-lithium alloy powder dispersion and the method of film removal treatment. In some preferred embodiments, a dry inert gas is introduced into the initial aluminum-lithium alloy powder dispersion and then a weak acid is added. After the reaction, the aluminum-lithium alloy powder dispersion is obtained. The surface of the initial aluminum-lithium alloy powder has an oxide film and / or a hydroxide film, and the weak acid includes at least one of hydrofluoric acid, acetic acid, and acetic acid. Before adding the weak acid to the initial aluminum-lithium alloy powder dispersion, a dry inert gas is introduced into the dispersion to take away a small amount of water formed after the weak acid is added, so as to prevent the lithium element in the aluminum-lithium alloy powder from reacting with water and avoid side reactions. Further preferably, after adding the weak acid, the temperature is kept at 30°C to 50°C for 1h to 3h, which is more conducive to fully removing the oxide film and / or hydroxide film on the surface of the initial aluminum-lithium alloy powder. The present invention does not limit the type of dry inert gas, and specifically, for example, it can be dry argon or dry nitrogen.

[0042] In some preferred embodiments of the present invention, the average particle size of the aluminum-lithium alloy powder that has not been treated with film removal is 1 μm to 100 μm, the lithium content is 2 wt% to 10 wt%, and the aluminum content is 90 wt% to 98 wt%. Based on the formation of a uniform nickel coating layer on the entire surface of the aluminum-lithium alloy powder, this preferred solution is more conducive to improving the combustion performance such as the combustion calorific value of the aluminum-lithium alloy powder. The average particle size of the aluminum-lithium alloy powder that has not been treated with film removal is, for example, 1 μm, 20 μm, 40 μm, 60 μm, 80 μm and 100 μm, the lithium content is, for example, 2 wt%, 4 wt%, 6 wt%, 8 wt% and 10 wt%, and the aluminum content is, for example, 90 wt%, 92 wt%, 94 wt%, 96 wt% and 98 wt%.

[0043] In some preferred embodiments of the present invention, both the first nickel salt solution and the second nickel salt solution have SO4 2- , Cl - Under this preferred embodiment, it is more conducive to forming a nickel layer with uniform thickness on the entire surface of the aluminum-lithium alloy powder, thereby improving the combustion performance.

[0044] In some preferred embodiments of the present invention, the solvent of the aluminum-lithium alloy powder dispersion, the solvent of the first nickel salt solution and the solvent of the second nickel salt solution all include at least one of ethanol, ethylene glycol and glycerol. Under this preferred embodiment, the nickel salt is more conducive to dissolution.

[0045] The present invention does not limit the form of solid-liquid separation, such as filtering, drying, etc. The drying conditions are, for example, a vacuum degree of no more than 0.095 MPa and a drying temperature of 50° C. to 80° C. After the solid-liquid separation of the present invention, screening is preferably performed to obtain a modified aluminum-lithium alloy powder.

[0046] In a second aspect, the present invention provides a metal-modified aluminum-lithium alloy powder, which is prepared by the preparation method described in the first aspect, and comprises an aluminum-lithium alloy core and a nickel coating layer coated on the outside of the aluminum-lithium alloy core. The present invention forms a nickel coating layer on the entire surface of the aluminum-lithium alloy powder, which can significantly improve the combustion performance of the aluminum-lithium alloy powder, such as the combustion calorific value.

[0047] In some preferred embodiments, the Ni content of the metal-modified aluminum-lithium alloy powder is 1wt%~4wt%, and the calorific value of combustion is 30000J / g~32000J / g.

[0048] The present invention is further described in detail below with reference to specific embodiments.

[0049] Example 1

[0050] A method for preparing modified aluminum-lithium alloy powder, comprising the following steps:

[0051] Step 1: adding initial aluminum-lithium alloy powder to an ethanol solvent, stirring under a nitrogen atmosphere while performing ultrasonic dispersion to obtain a dispersion of the initial aluminum-lithium alloy powder, wherein the average particle size of the initial aluminum-lithium alloy powder is 20 μm, the aluminum content of the initial aluminum-lithium alloy powder is 95 wt%, and the lithium content is 5 wt%; passing dry nitrogen into the dispersion of the initial aluminum-lithium alloy powder, while stirring, dripping hydrofluoric acid with a concentration of 3 wt% into the dispersion of the initial aluminum-lithium alloy powder, and after dripping the hydrofluoric acid, keeping the temperature at 45° C. for 2 h to obtain an aluminum-lithium alloy powder dispersion;

[0052] Step 2: Add a first nickel salt solution to the aluminum-lithium alloy powder dispersion obtained in step 1, wherein the first nickel salt solution is an ethanol solution of NiCl2, the concentration of nickel ions in the first nickel salt solution is 0.03 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.03, and stir the reaction at a temperature of 30°C to 40°C for 40 minutes to obtain a precursor modified powder dispersion;

[0053] Step three: Add a second nickel salt solution to the precursor modified powder dispersion of step two, the second nickel salt solution is an ethanol solution of NiCl2, the concentration of nickel ions in the second nickel salt solution is 0.3 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.05. Stir the reaction at a temperature of 60°C to 70°C for 60 minutes to obtain a modified powder dispersion. Filter, dry and sieve the modified powder dispersion to obtain a modified aluminum-lithium alloy powder. The vacuum degree of vacuum drying is not more than 0.095MPa, and the drying temperature is 60°C.

[0054] The modified aluminum-lithium alloy powder was characterized by transmission electron microscopy. The morphology of the modified aluminum-lithium alloy powder can be found in Figure 1 The modified aluminum-lithium alloy powder was characterized by scanning electron microscopy. The morphology of the modified aluminum-lithium alloy powder is shown in Figure 2 , EDS element analysis was performed on the coating layer and the core. The EDS spectra of the coating layer and the core are shown in Figure 3 and Figure 4 The coating layer is basically pure Ni, and most of the powder is Al (the Li element cannot be detected by EDS). Example 1 forms a uniform Ni coating layer on the powder surface.

[0055] Example 2

[0056] The preparation method of Example 1 was followed, except that in step 2, the reaction was stirred at 50° C. for 40 min to obtain a precursor modified powder dispersion.

[0057] Example 3

[0058] The preparation method of Example 1 was used as reference, except that in step 3, the reaction was stirred at 50° C. for 60 min to obtain a modified powder dispersion.

[0059] Example 4

[0060] The preparation method is carried out in accordance with Example 1, except that in step 2, the concentration of nickel ions in the first nickel salt solution is 0.05 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.08.

[0061] Example 5

[0062] The preparation method was carried out in accordance with Example 1, except that in step 3, the concentration of nickel ions in the second nickel salt solution was 0.5 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion was 0.1.

[0063] Comparative Example 1

[0064] The preparation method of Example 1 was followed, except that step 3 was not performed. In step 2, the reaction was stirred at a temperature of 30°C to 40°C for 60 minutes to obtain a modified powder dispersion. The modified powder dispersion was filtered, dried, and sieved to obtain a modified aluminum-lithium alloy powder. The vacuum degree of vacuum drying was not greater than 0.095MPa, and the drying temperature was 60°C. The modified aluminum-lithium alloy powder was characterized by scanning electron microscopy. The morphology of the modified aluminum-lithium alloy powder is shown in Figure 5 , it is impossible to form a coating layer on the surface of aluminum in the aluminum-lithium alloy powder.

[0065] Comparative Example 2

[0066] The preparation method of Example 1 was followed, except that step 2 was not performed. In step 3, a second nickel salt solution was added to the aluminum-lithium alloy powder dispersion of step 1, and the ratio of the volume of the second nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion was 0.05. The reaction was stirred at a temperature of 60°C to 70°C for 90 minutes. The modified aluminum-lithium alloy powder was characterized by scanning electron microscopy. The morphology of the modified aluminum-lithium alloy powder is shown in Figure 6 , the coating thickness is uneven.

[0067] Comparative Example 3

[0068] The preparation method of Example 1 was used as reference, except that in step 3, the reaction was stirred at 90° C. for 60 min to obtain a modified powder dispersion.

[0069] Test Case

[0070] The average coating thickness and uniformity of the average coating thickness of the modified aluminum-lithium alloy powders prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were tested by transmission electron microscopy. The thickness uniformity was expressed by the standard deviation result (10 thicknesses were randomly measured in the same field of view and the standard deviation was calculated). The combustion calorific value was tested by an oxygen bomb calorimeter. The test results are shown in Table 1.

[0071] Table 1

[0072]

[0073] Comparing Example 1 and the embodiment, compared with only using the first step reaction to coat the nickel layer on the surface of the aluminum-lithium alloy powder, the present invention adopts a two-step reaction coating, which can form a nickel layer on the surface of aluminum on the surface of the aluminum-lithium alloy powder, and can improve the calorific value of combustion. Comparing Example 2 and the embodiment, compared with only using the second step reaction to coat the nickel layer on the surface of the aluminum-lithium alloy powder, the present invention adopts a two-step reaction coating, which can control the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, improve the thickness uniformity, and improve the calorific value of combustion; Comparing Example 3 and the embodiment, the temperature of the second step reaction is not higher than 80°C, which can control the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, improve the thickness uniformity, and improve the calorific value of combustion.

[0074] Comparing Example 1 with Example 2, the first preset temperature is not higher than 40°C, which is more conducive to controlling the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, improving the thickness uniformity, and improving the combustion calorific value; comparing Example 1 with Example 3, the second preset temperature is not lower than 60°C, which is more conducive to forming a nickel coating layer with uniform thickness on the entire surface of the aluminum-lithium alloy powder, improving the combustion calorific value, and comparing Example 1 with Example 4, the concentration of nickel ions in the first nickel salt solution is 0.01mol / L~0.03mol / L, and the volume of the first nickel salt solution is 100% by volume. The volume ratio of the gold powder dispersion is 0.01~0.04, which is more conducive to controlling the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, improving the thickness uniformity, and improving the combustion calorific value. Comparing Example 1 and Example 5, the concentration of nickel ions in the second nickel salt solution is 0.2mol / L~0.4mol / L, and the volume ratio of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.03~0.07, which is more conducive to controlling the thickness of the nickel coating layer formed on the surface of the aluminum-lithium alloy powder, improving the thickness uniformity, and improving the combustion calorific value.

[0075] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a metal-modified aluminum-lithium alloy powder, characterized in that: include: Adding a first nickel salt solution to an aluminum-lithium alloy powder dispersion, stirring and reacting at a first preset temperature to obtain a precursor modified powder dispersion, wherein the first preset temperature is 30° C. to 60° C., the concentration of nickel ions in the first nickel salt solution is 0.01 mol / L to 0.05 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.1; the aluminum-lithium alloy powder in the aluminum-lithium alloy powder dispersion is an aluminum-lithium alloy powder that has been subjected to a film removal treatment, and the film removal treatment refers to the removal of an oxide film and / or a hydroxide film on the surface of the powder; Adding a second nickel salt solution to the precursor modified powder dispersion, stirring and reacting at a second preset temperature to obtain a modified powder dispersion, and separating the modified powder dispersion into a solid-liquid state to obtain a metal-modified aluminum-lithium alloy powder, wherein the second preset temperature is 50° C. to 80° C., the concentration of nickel ions in the second nickel salt solution is 0.1 mol / L to 0.5 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.01 to 0.1; A dry inert gas is introduced into a dispersion of an initial aluminum-lithium alloy powder, and then a weak acid is added to obtain the aluminum-lithium alloy powder dispersion after reaction, wherein the surface of the initial aluminum-lithium alloy powder has an oxide film and / or a hydroxide film, and the weak acid comprises at least one of hydrofluoric acid, acetic acid, and acetic acid; The lithium content of the aluminum-lithium alloy powder that has not been treated with film removal is 2wt%~10wt%, and the aluminum content is 90wt%~98wt%; The solvent of the aluminum-lithium alloy powder dispersion, the solvent of the first nickel salt solution and the solvent of the second nickel salt solution all include at least one of ethanol, ethylene glycol and glycerol.

2. The preparation method according to claim 1, characterized in that: The first preset temperature is 30°C to 40°C; and / or the second preset temperature is 60°C to 70°C.

3. The preparation method according to claim 1, characterized in that: The concentration of nickel ions in the first nickel salt solution is 0.01 mol / L to 0.03 mol / L, and the ratio of the volume of the first nickel salt solution to the volume of the aluminum-lithium alloy powder dispersion is 0.01 to 0.04; And / or, the concentration of nickel ions in the second nickel salt solution is 0.2 mol / L-0.4 mol / L, and the ratio of the volume of the second nickel salt solution to the volume of the precursor modified powder dispersion is 0.03-0.

07.

4. The preparation method according to claim 1, characterized in that: The reaction is stirred at the first preset temperature for 10 min to 60 min, and the reaction is stirred at the second preset temperature for 30 min to 90 min.

5. The preparation method according to claim 1, characterized in that: The average particle size of the aluminum-lithium alloy powder that has not been treated with film removal is 1μm~100μm.

6. The preparation method according to claim 1, characterized in that: The first nickel salt solution and the second nickel salt solution both have SO4 2- , Cl - At least one of them.

7. A metal-modified aluminum-lithium alloy powder, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 6, and comprises an aluminum-lithium alloy core and a nickel coating layer coated on the outside of the aluminum-lithium alloy core.

8. The metal-modified aluminum-lithium alloy powder according to claim 7, characterized in that: The Ni content of the metal-modified aluminum-lithium alloy powder is 1wt%-4wt%, and the combustion calorific value is 30000J / g-32000J / g.

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