Method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology

Abstract

The invention relates to a method for preparing bimetallic core-shell structure composite powder based on an acoustic resonance technology, and belongs to the technical field of powder metallurgy. Adding the micron matrix metal powder and the nano coating layer metal powder into a mixing tank, replacing air in the mixing tank with protective gas or active gas, and setting the pressure of the gas in the tank and the temperature of the tank body; and then three-section acoustic resonance coating powder preparation is carried out, and the bimetal core-shell structure composite powder is obtained. According to the method, different metal powder is driven by acoustic resonance to do violent disordered movement, the outer layer of micron metal powder is evenly and tightly coated with nano metal powder under the combined action of electrostatic force and other physical force, and finally the core-shell structure bimetal coated powder is obtained. The method is simple, the preparation efficiency is high, the applicability is wide, the thickness adjustable range of the coating layer of the obtained bimetallic coated powder is wide, the obtained bimetallic coated powder is uniform and compact, the powder particle morphology can be effectively maintained, and pollution of other elements is avoided.

Description

Technical Field

[0001] The present invention relates to a method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology, belonging to the technical field of powder metallurgy. Background Art

[0002] The bimetallic coated powder is a typical core-shell structure, characterized in that the outer layer of the matrix metal is tightly wrapped by a metal with other physical and chemical properties, which can improve the physical properties of the base metal, enhance chemical stability, improve processing performance, etc., and has broad application prospects in the fields of aerospace, electronic information, energy, mechanical manufacturing, etc.

[0003] At present, the methods for preparing bimetallic coated powders mainly include mechanical methods and chemical methods, such as mechanical ball milling method, bonding method, chemical reduction method, replacement method, etc. For example, Patent Application CN116586609A mechanically ball mills amorphous alloy powder and copper powder, resulting in the adhesion and spreading of the amorphous alloy on the surface of the copper powder particles, and finally forming a nano-thick film on the outer surface of the copper powder particles to prepare copper powder coated with a nano-thick amorphous metal layer. However, this process has a long ball milling time, low efficiency, and the morphology of metal particles is easily damaged during the ball milling process, affecting the subsequent manufacturing effect. Patent Application CN118371719A discloses a method for preparing non-metal nano-powder coated micron metal powder by spherical medium-assisted acoustic resonance mixing technology. Similar to the mechanical ball milling method, the movement of spherical media has a strong shearing effect on metal powders, and the morphology of metal powder particles is easily damaged during the coating process. The limited proportion of nano-powders results in a limited coating thickness and limited improvement in powder properties. Patent Application CN112708794A mixes tungsten powder with an electroplating solution (composed of anhydrous copper sulfate, concentrated sulfuric acid, etc.), undergoes two electroplating processes, and obtains copper-coated tungsten metal powder by high-temperature reduction in a hydrogen furnace. However, this process flow is complex, requires the preparation of a chemically complex electroplating solution, cannot avoid the residue of other trace elements, and the used electroplating solution seriously pollutes the environment.

[0004] Therefore, there is an urgent need to develop an acoustic resonance coating technology with good coating effect, convenience, batch production and no chemical pollution for preparing bimetallic core-shell structure composite powders. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology. This method prepares a bimetallic core-shell structure composite powder without destroying the original morphology of metal powder particles and without chemical pollution, and the adjustable range of the coating layer thickness is wide, meeting the requirements of different application scenarios and further improving the product performance.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows.

[0007] A method for preparing a bimetallic core-shell structured composite powder based on acoustic resonance technology, the method steps including:

[0008] Adding micron matrix metal powder and nano coating layer metal powder into a mixing tank, replacing the air in the mixing tank with a protective gas or an active gas, and setting the gas pressure and the tank body temperature inside the tank; then performing three-stage acoustic resonance coating powder making to obtain a bimetallic core-shell structured composite powder;

[0009] Among them, the resonance frequency of the first stage is 20 - 50 Hz, the mixing acceleration is 10 - 100 g, and the mixing time is 1 - 4 min; the second stage is that the resonance frequency is 60 - 100 Hz, the mixing acceleration is 110 - 200 g, and the mixing time is 3 - 20 min; the resonance frequency of the third stage is 40 - 70 Hz, the mixing acceleration is 80 - 130 g, and the mixing time is 1 - 6 min; 1 g = 9.8 m / s 2 。

[0010] Preferably, the average particle size of the micron matrix metal powder is 5 - 80 μm, and the average particle size of the nano coating layer metal powder is 20 - 150 nm.

[0011] Preferably, the molar ratio of the micron matrix metal powder to the nano coating layer metal powder is 0.25 - 4.0:1, and the thickness of the coating layer is 0.2 μm - 10 μm.

[0012] Preferably, the micron matrix metal powder includes metal elemental powder and metal alloy powder; the metal alloy powder is nickel-based alloy powder, aluminum-based alloy powder, titanium-based alloy powder, tungsten-based alloy powder, iron-based alloy powder, cobalt-based alloy powder, zirconium-based alloy powder, high-entropy alloy powder.

[0013] Preferably, the nano coating layer metal powder includes metal elemental powder and metal alloy powder; the metal alloy powder is nickel-based alloy powder, aluminum-based alloy powder, titanium-based alloy powder, tungsten-based alloy powder, iron-based alloy powder, cobalt-based alloy powder, zirconium-based alloy powder, high-entropy alloy powder.

[0014] Preferably, the micron matrix metal powder and the nano coating layer metal powder are different types of metal powders.

[0015] Preferably, the filling volume ratio of the micron matrix metal powder and the nano coating layer metal powder in the mixing tank is 50% - 80%.

[0016] Preferably, the protective gas is nitrogen or an inert gas (the gaseous simple substances corresponding to all group 0 elements in the periodic table); the active gas is oxygen or hydrogen.

[0017] Preferably, the absolute pressure inside the mixing tank is 50 kPa - 10 MPa.

[0018] Preferably, the temperature of the tank body in the mixing tank is -10°C to 100°C.

[0019] Beneficial effects

[0020] (1) The present invention is based on acoustic resonance technology. Through the acoustic resonance mixing of micron metal matrix powder and nano metal coating layer powder, under the combined action of electrostatic force and other physical forces, the nano metal powder is coated on the outer layer of the micron metal powder to obtain a core-shell structured double-metal coated powder. The process is simple, the preparation cost is low, the coating thickness is controllable, and the adjustable range of the thickness is wide (0.2μm - 10μm). The nano powder is evenly and densely distributed.

[0021] (2) Compared with the existing coating methods, there is no need to add auxiliary media such as ball milling beads and spherical media. On the basis of ensuring that the original particle shape of the metal powder is not damaged, the process flow is greatly reduced, and the pollution of other materials to the coated powder and the use of chemical agents are avoided.

[0022] (3) Filling inert gas in the tank can avoid oxidation reactions of metal powder, etc. Reacting active gas with metal powder can obtain specific metal compounds.

[0023] (4) In the three-stage acoustic resonance treatment, the first stage is pre-treatment and preliminary coating, the second stage is the main coating stage, and the third stage is the stabilization and densification stage; in the pre-treatment and preliminary coating stage, low-frequency vibration can initially form a coating layer, avoid damage to the surface of the matrix metal powder under extreme conditions, and keep the particles in a uniform dispersion state, avoiding the influence of aggregation on the coating layer uniformity under subsequent high acceleration and high frequency conditions; in the main coating stage, high frequency and high acceleration are used to stably increase the coating layer thickness, and high acceleration provides high impact force to improve the bonding strength of the coating layer and eliminate weak bonding points in the preliminary coating; in the stabilization and densification stage, on the basis of the coatings in the previous two stages, the stabilization process of the interface is completed to ensure that the coating layer firmly adheres to the surface of the matrix metal powder. Description of the drawings

[0024] Figure 1 SEM photograph of nickel-coated aluminum powder prepared in Example 1.

[0025] Figure 2 SEM photograph of copper-coated tungsten powder prepared in Example 2 and its EDS element distribution map (where a is the SEM photograph; b is the copper element distribution map; c is the tungsten element distribution map).

[0026] Figure 3 SEM photograph of bismuth-coated aluminum powder prepared in Example 3.

[0027] Figure 4SEM photograph of the iron-coated aluminum powder prepared in Example 4. Detailed implementation mode

[0028] The present invention will be further described in detail below with reference to specific examples.

[0029] Example 1:

[0030] A method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology. To improve the mechanical properties and energy release characteristics of nickel-aluminum energetic materials and prepare a nickel-coated aluminum bimetallic core-shell structure composite powder, the specific steps are as follows:

[0031] (1) The matrix metal powder is aluminum elemental powder with an average particle size of 10 μm, and the coating metal powder is nickel elemental powder with an average particle size of 50 nm.

[0032] (2) Weigh 140 g of aluminum powder and 300 g of nickel powder, with a molar ratio of 1:1. Select a 150 ml PC mixing tank and add the raw material powders into the mixing tank.

[0033] (3) Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it until the absolute pressure is about 1 kPa. Then fill the tank with inert nitrogen until the absolute pressure reaches 0.1 MPa.

[0034] (4) Set the three-stage acoustic resonance coating process parameters: the first-stage resonance frequency is 30 Hz, the mixing acceleration is 40 g, and the mixing time is 3 min; the second-stage resonance frequency is 60 Hz, the mixing acceleration is 110 g, and the mixing time is 15 min; the third-stage resonance frequency is 40 Hz, the mixing acceleration is 90 g, and the mixing time is 5 min to obtain nickel-coated aluminum powder with a core-shell structure.

[0035] As Figure 1 SEM photograph of the nickel-coated aluminum composite powder prepared in this example. It can be seen from the figure that the nickel coating layer uniformly and tightly adheres around the aluminum particles.

[0036] Example 2:

[0037] A method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology. To improve the mechanical properties and preparation process of tungsten-copper materials and solve problems such as material segregation during the preparation of tungsten-copper materials, a copper-coated tungsten bimetallic core-shell structure composite powder is prepared. The specific steps are as follows:

[0038] (1) The matrix metal powder is tungsten elemental powder with an average particle size of 10 μm, and the coating metal powder is copper elemental powder with an average particle size of 30 nm.

[0039] (2) Weigh 400 g of tungsten powder and 100 g of copper powder, with a molar ratio of 1.38:1. Select a 100-ml metal mixing tank with temperature control function, and add the raw material powders into the mixing tank.

[0040] (3) Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it until the absolute pressure reaches about 1 kPa. Then fill the tank with inert nitrogen gas until the absolute pressure reaches 0.1 MPa.

[0041] (4) Set the cooling water temperature of the mixing tank to 30 °C.

[0042] (5) Set the process parameters of the three-stage acoustic resonance coating: the first-stage resonance frequency is 50 Hz, the mixing acceleration is 100 g, and the mixing time is 4 min; the second-stage resonance frequency is 80 Hz, the mixing acceleration is 180 g, and the mixing time is 10 min; the third-stage resonance frequency is 60 Hz, the mixing acceleration is 100 g, and the mixing time is 6 min, to obtain copper-coated tungsten powder with a core-shell structure.

[0043] As Figure 2 This is the SEM photograph and EDS element distribution map of the copper-coated tungsten composite powder prepared in this example. It can be seen from the figure that the copper coating layer uniformly and tightly adheres around the tungsten particles.

[0044] Example 3:

[0045] A method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology. To improve the mechanical properties and energy release characteristics of the bismuth-aluminum active material and solve the problems such as material segregation during the preparation of the aluminum-bismuth material, a bismuth-coated aluminum bimetallic core-shell structure composite powder is prepared. The specific steps are as follows:

[0046] (1) The matrix metal powder is aluminum elemental powder with an average particle size of 25 μm, and the coating metal powder is bismuth elemental powder with an average particle size of 1 μm.

[0047] (2) Weigh 50 g of aluminum powder and 450 g of bismuth powder, with a molar ratio of 0.86:1. Select a 150-ml metal mixing tank with temperature control function, and add the raw material powders into the mixing tank.

[0048] (3) Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it until the absolute pressure reaches about 1 kPa. Then fill the tank with inert nitrogen gas until the absolute pressure reaches 0.1 MPa.

[0049] (4) Set the cooling water temperature of the mixing tank to 20 °C.

[0050] (5) Set the process parameters of the three-stage acoustic resonance coating: the resonance frequency of the first stage is 20 Hz, the mixing acceleration is 30 g, and the mixing time is 4 min; the resonance frequency of the second stage is 60 Hz, the mixing acceleration is 110 g, and the mixing time is 15 min; the resonance frequency of the third stage is 40 Hz, the mixing acceleration is 90 g, and the mixing time is 5 min, to obtain bismuth-coated aluminum powder with a core-shell structure.

[0051] As Figure 3 This is the SEM photograph of the bismuth-coated aluminum composite powder prepared in this example. It can be seen from the figure that the bismuth coating layer uniformly and tightly adheres around the aluminum particles, and the morphology of the metal powder particles is consistent with the original morphology.

[0052] Example 4:

[0053] A method for preparing a bimetallic core-shell structure composite powder based on acoustic resonance technology. To improve the mechanical properties of iron-aluminum materials and the preparation process, a bimetallic core-shell structure composite powder of iron-coated aluminum is prepared. The specific steps are as follows:

[0054] (1) The matrix metal powder is aluminum elemental powder with an average particle size of 25 μm, and the coating layer metal powder is iron elemental powder with an average particle size of 1 μm.

[0055] (2) Weigh 130 g of aluminum powder and 370 g of iron powder, with a molar ratio of 0.73:1. Select a 200 ml PC mixing tank and add the raw material powders into the mixing tank.

[0056] (3) Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it until the absolute pressure is about 1 kPa, and then fill the tank with inert nitrogen until the absolute pressure reaches 0.1 MPa.

[0057] (4) Set the process parameters of the three-stage acoustic resonance coating: the resonance frequency of the first stage is 30 Hz, the mixing acceleration is 40 g, and the mixing time is 3 min; the resonance frequency of the second stage is 70 Hz, the mixing acceleration is 130 g, and the mixing time is 15 min; the resonance frequency of the third stage is 50 Hz, the mixing acceleration is 110 g, and the mixing time is 5 min, to obtain iron-coated aluminum powder with a core-shell structure.

[0058] As Figure 4 This is the SEM photograph of the iron-coated aluminum composite powder prepared in this example. It can be seen from the figure that the iron coating layer uniformly and tightly adheres around the aluminum particles, and the coating effect is consistent.

[0059] In summary, the invention includes but is not limited to the above examples. Any equivalent replacement or partial improvement carried out under the spirit and principle of the present invention will be regarded as within the protection scope of the present invention.

Claims

1. A method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology, characterized in that: The method steps include: Adding micron base metal powder and nano-coating layer metal powder into a mixing tank, replacing the air in the mixing tank with protective gas or active gas, setting the gas pressure in the tank and the tank temperature; then performing three-stage acoustic resonance coating powder making to obtain a bimetallic core-shell structure composite powder; The first section has a resonance frequency of 20-50 Hz, a mixed acceleration of 10-100 g, and a mixing time of 1-4 min; the second section has a resonance frequency of 60-100 Hz, a mixed acceleration of 110-200 g, and a mixing time of 3-20 min; the third section has a resonance frequency of 40-70 Hz, a mixed acceleration of 80-130 g, and a mixing time of 1-6 min; 1 g = 9.8 m / s 2 .

2. A method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The average particle size of the micron base metal powder is 5 to 80 μm, and the average particle size of the nano coating layer metal powder is 20 to 150 nm.

3. A method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology as claimed in claim 1 or 2, characterized in that: The molar ratio of the micron base metal powder to the nanometer coating layer metal powder is 0.25-4.0:1, and the thickness of the coating layer is 0.2 μm-10 μm.

4. The method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The micron-based metal powder includes metal element powder and metal alloy powder; the metal alloy powder includes nickel-based alloy powder, aluminum-based alloy powder, titanium-based alloy powder, tungsten-based alloy powder, iron-based alloy powder, cobalt-based alloy powder, zirconium-based alloy powder and high entropy alloy powder.

5. A method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology as claimed in claim 1 or 4, characterized in that: The nano-coated layer metal powder includes metal element powder and metal alloy powder; the metal alloy powder is nickel-based alloy powder, aluminum-based alloy powder, titanium-based alloy powder, tungsten-based alloy powder, iron-based alloy powder, cobalt-based alloy powder, zirconium-based alloy powder, and high entropy alloy powder.

6. The method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The micron base metal powder and the nanometer coating layer metal powder are different types of metal powders.

7. The method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The filling volume ratio of the micron base metal powder and the nanometer coating layer metal powder in the mixing tank is 50% to 80%.

8. The method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The protective gas is nitrogen or an inert gas; the active gas is oxygen or hydrogen.

9. The method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1, characterized in that: The absolute pressure in the mixing tank is 50 kPa to 10 MPa.

10. A method for preparing bimetallic core-shell structure composite powder based on acoustic resonance technology according to claim 1 or 9, characterized in that: The tank body temperature in the mixing tank is -10°C to 100°C.

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