Preparation method of aluminum-based alloy powder using CO2 as shielding gas and aluminum-based alloy metal powder

Abstract

The invention discloses a preparation method of aluminum-based alloy powder using CO2 as shielding gas and aluminum-based alloy metal powder, relates to the field of metal powder preparation, and aims to solve the problems of high cost, low powder fluidity and low tap density in the prior art. And introducing carbon dioxide as shielding gas, melting, preserving heat, atomizing to prepare powder, cooling and screening. Carbon dioxide is used as shielding gas and can be obtained at low cost, liquid carbon dioxide is convenient to store and transport, the production cost can be effectively reduced, the molecular weight of carbon dioxide is higher than that of nitrogen, atomization kinetic energy higher than that of nitrogen can be obtained, and therefore the particle size of powder is refined, and generation of satellite powder and hollow powder is reduced; and the powder fluidity and the tap density are improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal powder preparation, in particular to a method for preparing aluminum-based alloy powder using CO2 as protective gas and aluminum-based alloy metal powder. Background Art

[0002] Aluminum-based alloy melts are very easy to oxidize. Even if argon is used as protection in the traditional gas atomization process, a nano-scale oxide film will still form on the powder surface, and the cost of argon recovery is high. In addition, if conventional nitrogen is used for atomization, satellite powder and hollow powder are easily produced, which affects the fluidity and tap density of the powder. As an industrial by-product, CO2 is low-cost and environmentally friendly, and liquid CO2 is easy to store and transport. The molecular weight of CO2 (44 g / mol) is higher than that of nitrogen (28 g / mol), which can theoretically increase the atomization kinetic energy and refine the powder particle size. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for preparing aluminum-based alloy powder using CO2 as a protective gas and aluminum-based alloy metal powder, which can effectively solve the problems in the background technology.

[0004] In order to achieve the above object, the present invention discloses a method for preparing aluminum-based alloy powder using CO2 as protective gas, and the technical scheme adopted is comprising the following steps: Step 1, weigh the metal materials of each element according to the alloy composition and proportion and put them into a container; Step 2, evacuate the container, and then introduce CO2 protective gas. By using CO2 as protective gas, the atomization kinetic energy is increased and the powder particle size is refined. The metal material is melted in the container. When the metal material is completely melted, it is kept warm and the guide tube connected to the bottom of the container is heated; Step 3: After the temperature of the guide tube reaches the set value, the atomizing gas is turned on for atomization and powder making. The alloy melt flowing out from the bottom of the guide tube is impacted by the atomizing gas and broken into small droplets and solidified to form powder; Step 4: After the atomization and powder making is completed, cooling and screening are performed to obtain an aluminum-based alloy metal powder.

[0005] As a preferred technical solution of the present invention, the purity of the metal material is greater than 99%, so that the amount of impurities other than the components in the alloy powder is maintained at a relatively small value.

[0006] As a preferred technical solution of the present invention, in step 2, a three-stage pump is used to perform a vacuum operation so that the pressure P in the container is less than 3×10 -2 Pa. Extracting as much gas as possible from the container and then introducing carbon dioxide can increase the concentration of carbon dioxide.

[0007] As a preferred technical solution of the present invention, in step 2, after the metal material is completely melted, it is kept warm at a temperature of 900-1000°C.

[0008] As a preferred technical solution of the present invention, the diameter of the flow guide tube is 1-4 mm.

[0009] As a preferred technical solution of the present invention, in step 3, the atomizing gas is turned on after the temperature of the flow guide tube reaches 900-1000°C.

[0010] As a preferred technical solution of the present invention, in step 3, the atomizing gas is generated by an atomizing nozzle, the atomizing nozzle is an annular structure, the outlet gap size is 0.2mm~0.8mm, the atomizing nozzle is flush with the outlet of the guide tube, and the angle between the guide tube and the nozzle is 50~60°.

[0011] As a preferred technical solution of the present invention, the atomizing gas pressure is 6-10 MPa.

[0012] The invention also discloses aluminum-based alloy metal powder prepared based on the method.

[0013] Compared with the prior art, the beneficial effects of the present invention are: by using carbon dioxide as a protective gas, the present invention can not only be obtained at a low cost, but also liquid carbon dioxide is easy to store and transport, which can effectively reduce production costs, and the molecular weight of carbon dioxide is higher than that of nitrogen, and higher atomization kinetic energy can be obtained than that of nitrogen, thereby refining the powder particle size, reducing the generation of satellite powder and hollow powder, and improving the powder fluidity and tap density. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The SEM image of the aluminum-based alloy metal powder prepared by the present invention is Figure 1 ; Figure 2 The SEM image of the aluminum-based alloy metal powder prepared by the present invention is Figure 2 ; Figure 3 The SEM image of the aluminum-based alloy metal powder prepared by the present invention is Figure 3 . DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0016] This embodiment discloses a first implementation mode of the present invention, and the adopted technical solution is to include the following steps: Step 1, weighing a metal block containing 80% Al, 10% Sn and 10% Ni by weight, and placing the metal block in a graphite crucible; Step 2: Use a three-pole pump to evacuate the graphite crucible to a vacuum of 3×10 -2 Pa, then introduce 99.99% CO2, turn on the smelting power supply, heat the metal block, and preheat the guide tube connected to the bottom of the graphite crucible; when the metal block is completely melted, keep it at 960℃, and continue to heat the guide tube; Step 3, set the diameter of the guide tube to 2mm, the outlet gap of the nozzle to 0.3mm, and the angle between the nozzle and the guide tube to 50°. When the temperature in the guide tube reaches 960°C, turn on the atomizing gas carbon dioxide and set the atomization pressure to 7MPa. The alloy liquid in the crucible flows into the guide tube. During the atomization process, the high-pressure atomizing gas released through the nozzle impacts the alloy melt flowing out of the end of the guide tube, causing the melt to break into small droplets; Step 4: The fine alloy droplets solidify into spherical particles or sub-spherical particles in flight. After the particle powder is cooled, it is sieved to obtain Al-10Sn-10Ni wt.% alloy powder with the required particle size. The Al-10Sn-10Ni wt.% alloy powder is scanned using an electron microscope to obtain the following: Figures 1 to 3 SEM images shown. Example 2

[0017] The difference between this embodiment and embodiment 1 is that in step 2, after the metal block is completely melted, it is kept at 900°C; In step 3, the diameter of the flow tube is set to 1 mm, the outlet gap of the nozzle is set to 0.4 mm, and the angle between the nozzle and the flow tube is set to 60°. When the temperature in the flow tube reaches 900°C, the atomizing gas carbon dioxide is turned on and the atomizing pressure is set to 6 MPa. Example 3

[0018] The difference between this embodiment and embodiment 1 is that in step 2, after the metal block is completely melted, it is kept at 1000°C; In step 3, the diameter of the flow tube is set to 4 mm, the outlet gap of the nozzle is set to 0.6 mm, and the angle between the nozzle and the flow tube is set to 55°. When the temperature in the flow tube reaches 1000°C, the atomizing gas carbon dioxide is turned on and the atomizing pressure is set to 8 MPa.

[0019] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing aluminum-based alloy powder using CO2 as protective gas, characterized in that: The following steps are involved: Step 1, weigh the metal materials of each element according to the alloy composition and proportion and put them into a container; Step 2, evacuate the container, then introduce CO2 protective gas, melt the metal material in the container, keep the metal material warm when it is completely melted, and heat the guide pipe connected to the bottom of the container; Step 3: After the temperature of the guide tube reaches the set value, the atomizing gas is turned on for atomization and powder making. The alloy melt flowing out from the bottom of the guide tube is impacted by the atomizing gas and broken into small droplets and solidified to form powder; Step 4: After the atomization and powder making is completed, cooling and screening are performed to obtain an aluminum-based alloy metal powder.

2. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 1, characterized in that: In step 1, the purity of the metal material is greater than 99%.

3. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 1, characterized in that: In step 2, a three-stage pump is used to perform a vacuum operation so that the pressure in the container is P < 3×10 -2 Pa.

4. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 1 or 3, characterized in that: In the step 2, after the metal material is completely melted, it is kept warm at a temperature of 900-1000°C.

5. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 4, characterized in that: The diameter of the flow guide tube is 1-4 mm.

6. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 1, characterized in that: In step 3, the atomizing gas is turned on after the temperature of the draft tube reaches 900-1000°C.

7. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 1 or 6, characterized in that: In step 3, the atomizing gas is generated by an atomizing nozzle, which is an annular structure with an outlet gap size of 0.2 mm to 0.8 mm. The atomizing nozzle is flush with the outlet of the guide tube, and the angle between the guide tube and the nozzle is 50 to 60 degrees.

8. The method for preparing aluminum-based alloy powder using CO2 as protective gas according to claim 7, characterized in that: The atomizing gas pressure is 6-10 MPa.

9. An aluminum-based alloy metal powder, characterized in that: The powder is prepared by the method for preparing aluminum-based alloy powder using CO2 as protective gas as described in claim 1.

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