CN115041691A - Preparation method and preparation device of low-oxygen aluminum and aluminum alloy powder - Google Patents

Abstract

The invention belongs to the technical field of powder metallurgy and additive manufacturing, and particularly relates to a preparation method and a preparation device of low-oxygen aluminum and aluminum alloy powder, which comprises the following steps: s1, adding elements into the aluminum ingot and the intermediate alloy, and smelting by a vacuum smelting method to obtain alloy melt; s2, adding the molten alloy prepared in the step S1 into an atomizing tower for atomization, and adjusting the atomization pressure of inert gas to prepare the required aluminum and aluminum alloy powder; s3, coating an organic film on the surface of the S2 aluminum and aluminum alloy powder through a section of gaseous organic matter molecular layer at the tail end of the cooling flight of the aluminum and aluminum alloy powder prepared by atomization; the organic matter is reductive organic matter and does not contain oxygen element; and S4, freeze drying the aluminum and aluminum alloy powder coated with the S3 to obtain the low-oxygen aluminum and aluminum alloy powder. The aluminum and aluminum alloy powder prepared by the invention can prevent the oxidation problem of the aluminum powder, especially the superfine aluminum powder, in the storage and deep processing process due to the organic matter film layer.

Description

Preparation method and preparation device of low-oxygen aluminum and aluminum alloy powder

Technical Field

The invention belongs to the technical field of powder metallurgy and additive manufacturing, and particularly relates to a preparation method and a preparation device of low-oxygen aluminum and aluminum alloy powder.

Background

Aluminum and aluminum alloys have many excellent characteristics such as low density, high specific strength, good electrical and thermal conductivity, easy acquisition, and the like, and have been widely used in many fields such as aerospace, automobiles, electronics, civilian use, and the like. In recent years, with the rapid development of automobile lightweight and aerospace industry, aluminum alloy parts have more and more requirements on integrated and complex three-dimensional structures, and the traditional processing mode is increasingly difficult to meet. Additive manufacturing and near-net-shape manufacturing technologies such as 3D printing, powder metallurgy, injection molding and the like are attracting attention due to their simple manufacturing process, relatively low production cost and short development cycle. The aluminum alloy prepared by additive manufacturing or powder metallurgy has fine crystal grains and uniform components, and the mechanical property of the aluminum alloy is superior to that of the traditional cast aluminum alloy material and even equivalent to that of wrought aluminum alloy. At present, technologies such as 3D printing and injection molding have been gradually developed to the industrialization stage from research and development in the aluminum alloy industry, but aluminum and aluminum alloy powder with excellent performance and low cost are still key factors that restrict the rapid development of the industry.

Aluminum and aluminum alloy powders that are directly used in the preparation of complex parts generally require higher purity, controllable particle size distribution, good morphology, and lower production costs. The aluminum and aluminum alloy powder prepared by the atomization method is nearly spherical in shape, controllable in particle size range and high in production efficiency, and is a main raw material for processing high-performance aluminum-based complex parts at present. In recent years, on the basis of an atomization method, aluminum and aluminum alloy powder has been greatly improved in the aspects of component design and shape control technology by reasonable methods such as component optimization, high-purity raw material control, improvement of atomization nozzle design, control of protective atmosphere and the like, but due to high activity of aluminum, an aluminum oxide film is still generated on the surface of the powder in the preparation and storage processes, and oxygen is increased to the powder. Once formed, the oxide film is almost free from any reducing agent to remove the oxide film in the subsequent use process, and finally the improvement of the performance of the bulk material of the part is influenced. Therefore, reducing the oxygen content of aluminum and aluminum alloy powders in a suitable manner becomes the core to improve the performance of aluminum alloy powder metallurgy and 3D printed parts.

At present, in order to reduce the oxygen content in aluminum and aluminum alloy powder in the industry, two main points are focused, on one hand, in the powder preparation process, high-purity nitrogen or other inert gases are introduced into the alloy melting and atomizing environment for protection, so that the formation of an alumina shell in the powder preparation process is hindered. However, the method has limited resistance to oxidation of the aluminum powder, and the product is inevitably contacted with moisture, oxygen and the like in the air to react in the storage and transportation process of separating from the preparation cavity until a completely coated aluminum oxide shell grows to increase oxygen in the powder, and the oxygen increase of the part is obviously promoted along with the thinning of the particle size of the powder. In order to overcome the oxygen increasing in the packaging and transportation process, the patent CN 101992295A, CN 110330723A, CN 110449574A and the like hinder the high-temperature oxidation and flammability problems in the storage process of the aluminum powder by adding films of silicon oxide, organic siloxane, graphite and the like in the post-treatment process of the prepared aluminum powder, but the method easily causes the oxygen increasing of the aluminum powder in the preparation process, and the films are difficult to remove once formed, are impurities for the preparation of aluminum alloy parts, and the aluminum powder is usually used as a combustion improver and a coating. In view of the above, a preparation method of the low-oxygen aluminum and aluminum alloy powder suitable for deep processing such as 3D printing, powder metallurgy, injection molding and the like is developed, can simultaneously overcome the oxidation problem in the processes of powder preparation, storage and use, and has important significance for the development of the industry.

Disclosure of Invention

In order to solve the technical problems, the invention provides a preparation method and a preparation device of low-oxygen aluminum and aluminum alloy powder.

The invention is realized by the following technical scheme.

The invention firstly provides a preparation method of low-oxygen aluminum and aluminum alloy powder, which comprises the following steps:

s1, adding elements into the aluminum ingot and the intermediate alloy, and smelting by a vacuum smelting method to obtain alloy melt;

s2, uniformly adding the alloy melt prepared in the S1 into an atomizing tower for atomizing, and adjusting the atomizing pressure of inert gas to prepare the required aluminum and aluminum alloy powder;

s3, coating an organic film on the surface of the S2 aluminum and aluminum alloy powder through a section of gaseous organic matter molecular layer at the tail end of the cooling flight of the aluminum and aluminum alloy powder prepared by atomization;

the organic matter is a reductive organic matter, does not react with high-activity aluminum powder and other metal elements, does not contain oxygen, has strong hydrophobicity, and can isolate moisture; the organic matter coats the surface of the aluminum and aluminum alloy powder to form a film, so that the aluminum and aluminum alloy powder can be isolated from external oxygen and water, and an oxidation film is prevented from being generated;

and S4, freeze drying the aluminum and aluminum alloy powder coated with the S3 to obtain the low-oxygen aluminum and aluminum alloy powder.

Preferably, in S3, when reacting with oxygen, the organic matter has higher reducibility than the aluminum and aluminum alloy powder, i.e., the organic matter preferentially reacts with oxygen under certain conditions, thereby achieving the effect of preventing the aluminum powder from oxidizing and further improving the protective effect.

Preferably, in S3, the organic substance is solid at room temperature, so as to ensure the stability of the organic film during transportation and deep processing.

Preferably, in S3, the organic substance is a mixture of n-heneicosane and cyclododecane.

Preferably, in S3, the addition amount of cyclododecane is 0.1 to 1% by mass of n-heneicosane.

Preferably, in S3, the temperature of the gaseous organic matter is 120-200 ℃, and the temperature of the aluminum and aluminum alloy powder entering the gaseous organic matter layer is less than 50 ℃.

Preferably, in S3, the organic thin film has a thickness of 100 to 300 nm.

Preferably, in S1, the vacuum degree of vacuum melting is in the range of 4-6.7 × 10 ^-3 Pa, and the melting temperature is 700-1000 ℃.

Preferably, in S4, the freeze-drying temperature is-30 to 10 ℃.

The present invention also provides an apparatus for preparing low-oxygen aluminum and aluminum alloy powder, comprising:

the outlet of the vacuum smelting furnace is communicated with the inlet of a gas atomization chamber, the outlet of the gas atomization chamber is communicated with the inlet of a gas organic matter coating chamber, and the outlet of the gas organic matter coating chamber is communicated with the inlet of a freeze drying chamber; further comprising:

the organic matter evaporating chamber, the organic matter gas of evaporation in the organic matter evaporating chamber pass through the admission line with gaseous organic matter tectorial membrane room intercommunication, the indoor material of gaseous organic matter tectorial membrane is discharged through ejection of compact pipeline and is circulated in stating the organic matter evaporating chamber.

Compared with the prior art, the invention has the following beneficial effects:

in the method, an organic matter coating process is added in the conventional inert gas atomization powder preparation process, atomized aluminum liquid drops pass through a gaseous organic matter molecular layer after flying and cooling, and low-temperature aluminum powder absorbs the heat of the gaseous organic matter to condense the organic matter on the surface of the aluminum powder, so that the effect of complete coating and wrapping is achieved.

The n-heneicosane and cyclododecane organic matter selected in the invention is mixed, belongs to a reducing organic matter, does not contain oxygen in molecular formula, has strong hydrophobicity, does not react with high-activity aluminum powder at all, and even can preferentially react with oxygen under certain conditions, thereby achieving the effect of preventing the aluminum powder from being oxidized. The organic matter is solid at room temperature, has strong adhesion, has lower boiling point and high thermal cracking temperature (the boiling point is about 100 ℃, the cracking temperature is more than 350 ℃ under inert atmosphere), is matched with reasonable temperature control, is very convenient to coat by adopting a physical gas phase coating mode, has simple operation and low cost in a gas phase coating mode compared with the traditional chemical coating method, and can greatly improve the uniformity and thickness controllability of a coating film layer, and the organic matter film can be thoroughly removed by adopting lower heating temperature in the subsequent use process without introducing impurities.

The aluminum and aluminum alloy powder prepared by the invention has a thin organic matter film layer, so that the problem of oxidation of the aluminum powder, especially superfine aluminum powder, in the storage process can be solved, the oxygen content of the prepared aluminum and aluminum alloy powder is less than or equal to 300ppm, and the oxygen content is irrelevant to the particle size of the powder, so that the problems that the traditional powder is smaller in particle size and higher in oxygen content are solved, and the preparation method is very suitable for the requirements of high activity and low oxidation of the powder in the production of powder metallurgy products. In addition, because the organic film layer is arranged, the laser reflectivity in the 3D printing process can be reduced, and the problem of high aluminum powder laser reflectivity in the 3D printing process is solved.

Drawings

FIG. 1 is a flow chart of a process for preparing low-oxygen aluminum and aluminum alloy powder according to the present invention;

FIG. 2 is a schematic structural diagram of an apparatus for preparing low-oxygen aluminum and aluminum alloy powder according to the present invention;

FIG. 3 is an SEM image of pure aluminum powder prepared in example 1 of the present invention;

description of reference numerals:

1. a vacuum smelting furnace; 2. a gas atomization chamber; 3. a gaseous organic matter film coating chamber; 4. a freeze drying chamber; 5. an organic matter evaporation chamber; 6. aluminum alloy melt; 7. a mixture of n-heneicosane and cyclododecane; 8. aluminum and aluminum alloy powders.

Detailed Description

In order to make the technical solutions of the present invention better understood and implemented by those skilled in the art, the present invention is further described below with reference to the following specific embodiments and the accompanying drawings, but the embodiments are not meant to limit the present invention.

The experimental methods and the detection methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

As shown in fig. 1, the method for preparing low-oxygen aluminum and aluminum alloy powder according to the embodiment of the present invention includes 4 steps, wherein the 4 steps can be implemented by the schematic diagram of the apparatus shown in fig. 2:

step 1, vacuum melting

Adding elements into an aluminum ingot and an intermediate alloy according to the required chemical component ratio, placing the aluminum ingot and the intermediate alloy into a vacuum smelting furnace 1, firstly filling nitrogen, and then vacuumizing to 4-6.7 multiplied by 10 ^-3 Pa, heating to 700-1000 ℃ according to the melting temperature of the aluminum and the added intermediate alloy, fully melting the block material to liquid, and controlling the melting temperature to be 4-6.7 multiplied by 10 ^-3 Pa vacuum smelting can reduce the burning loss of aluminum and alloy elements thereof and prevent the generation of oxygen and oxide inclusions in the alloy liquid.

Step 2, inert gas atomization

Uniformly adding the prepared aluminum alloy melt 6 into a gas atomization chamber 2 for atomization, and adjusting the inert gas atomization pressure to prepare the required aluminum and aluminum alloy powder 8; the method is not particularly limited to the types of gases and the pressures of the gases for atomizing the inert gases, and can be selected and adjusted by a person skilled in the art according to the actual production conditions, the particle size requirements of the products and the quality requirements.

Step 3, coating the gaseous organic matter

The creativity of the invention is that the atomized aluminum powder flies and cools in inert gas, and freely falls into a gas organic matter coating chamber 3 after solidification, the gas organic matter is composed of n-heneicosane and cyclododecane in a certain proportion, the n-heneicosane is used as a main coating material, the addition of the cyclododecane is used for increasing the adhesiveness of the film, and the addition proportion of the cyclododecane is controlled between 0.1-1% (mass ratio to the n-heneicosane). The n-heneicosane and cyclododecane are free of oxygen molecules and most importantly, both are solid at room temperature and stable gas molecules when heated to above 200 ℃, thereby facilitating gas phase coating. It was also found in earlier studies that: cyclododecane, which has good adhesion to most solids when in the solid state, is more strongly adhered to aluminum than solid n-heneicosane, which is commonly used for temporary reinforcement of cultural relics repairs. After the aluminum powder particles are mixed and added with the n-heneicosane, the coating effect of the n-heneicosane on the metal aluminum alloy particles can be greatly improved, and the problem of local abrasion and falling of a coating layer caused by mutual friction after the aluminum powder particles are coated is reduced. However, due to the characteristics of glue-like materials, when the addition amount exceeds 1% or more, the aluminum powder particles coated with the coating are easy to be bonded in the cooling process, a phenomenon similar to satellite balls is generated, and the dispersibility of the aluminum powder particles is affected, which is unfavorable for subsequent screening classification or 3D printing. Therefore, the invention adopts the organic matter of the n-heneicosane and the cyclododecane which are mixed according to a certain proportion to carry out coating.

The gas temperature of the organic matters is controlled to be 120-200 ℃, and the gas is easy to be locally liquefied due to too low temperature, so that the powder coating layer is not uniform enough, and the phenomenon that the coating layer is too thick on the surface of powder particles after solidification is easy to occur; and the excessive temperature can cause the n-heneicosane and the cyclododecane gas to generate partial cracking to generate short-chain hydrocarbon which cannot return to a solid state after being cooled. So that the solid coating effect of the organic matter can not be achieved when the organic matter is cooled.

The thickness of coating accessible organic matter gas chamber highly synthesizes with the particle size of atomizing powder and regulates and control, and control is suitable at 100 ~ 300nm, shows in the research of earlier stage: when the coating layer exceeds 300nm, the bubbling phenomenon of a pressed green body is easily caused in the subsequent 3D printing or powder metallurgy sintering process, and the densification effect of powder to solid is influenced, so the coating layer thickness with the optimal coating thickness controlled within 100-300 nm is preferably comprehensively considered. But the possibility that the coating layer with the thickness of more than 300nm can still obtain high densification effect of the aluminum and aluminum alloy powder is not excluded through the fine control of the powder sintering process and the development of the coating layer removing process before sintering.

The mixture 7 of the n-heneicosane and the cyclododecane is heated and evaporated in the organic matter evaporation chamber 5, and the organic matter gas evaporated in the organic matter evaporation chamber is conveyed to the gas organic matter coating film 3 through a gas inlet pipeline to coat the aluminum alloy melt 6.

Step 4, cooling and drying

The free falling body of the powder coated by the gas organic matter falls into the freeze drying chamber 4, so that the organic matter coated on the surface can be rapidly solidified, the temperature of cooling and drying is controlled to be-30-10 ℃, the corresponding effect can be obtained at the excessively low temperature, but the high power consumption and the cold consumption requirement of refrigeration equipment are caused, and the organic matter coating cannot be rapidly cooled to form a solid state at the cooling temperature of more than 10 ℃, so that the coating effect is influenced, and the phenomena of adhesion and incomplete coating layer occur. The powder after the short-time drying can be used directly by sieving and classifying in an air atmosphere.

The invention is further illustrated by the following specific examples.

Example 1

The preparation method of the low-oxygen pure aluminum powder comprises the following specific steps:

step 1, vacuum melting

Cleaning and drying a pure aluminum alloy ingot, adding the pure aluminum alloy ingot into a melting crucible, and vacuumizing the melting crucible to 4 x 10 ^-3 Pa, and then heated to 700 ℃ to melt.

Step 2, inert gas atomization

After the alloy is melted, 99.995% nitrogen is adopted to atomize the aluminum liquid into aluminum powder with D50 of 40um under the condition that the pressure is 2 Mpa.

Step 3, coating the gaseous organic matter

The method comprises the following steps of taking n-heneicosane and cyclododecane as raw materials, wherein the adding proportion of the cyclododecane is 0.1%, placing a mixture of the n-heneicosane and the cyclododecane in a heating container, heating to generate mixture steam with the temperature of 120 ℃, setting the steam height to be 300mm, and allowing atomized aluminum powder to freely fall, pass through the steam and cover with gas organic matters.

Step 4, freeze drying

Controlling the temperature of the drying oven at-30 ℃, and collecting aluminum powder.

Through detection, the granularity of the aluminum powder is D50 value 40um, the thickness of the thin film layer is about 100nm, the appearance of the prepared powder is shown in figure 3, and the sphericity and the dispersity of the powder are good. The powder is placed in the air for 72 hours and then detected, the oxygen content in the powder is detected to be 180ppm, the powder is used for preparing complex parts in powder metallurgy, after the powder is pressed and sintered for 30min in a nitrogen atmosphere at 500 ℃, the impurity content of the powder is detected to be equivalent to that of the powder, the oxygen content is only increased by 10ppm, and the increase of the oxygen content in the deep processing application of the aluminum powder is well avoided.

Example 2

The preparation method of the low-oxygen Al-Si-10Mg alloy powder comprises the following specific steps:

step 1, vacuum melting

Adding pure aluminum ingot, aluminum-silicon intermediate alloy and magnesium ingot into a melting crucible according to a designed proportion, and vacuumizing to 6.7 x 10 ^-3 Pa, heating to 1000 ℃ to melt.

Step 2, inert gas atomization

After the alloy is melted, 99.995% nitrogen is adopted to atomize the aluminum liquid into aluminum powder with D50 being 38um under the condition that the pressure is 2 Mpa.

Step 3, coating the gaseous organic matter

The method comprises the following steps of taking n-heneicosane and cyclododecane as raw materials, enabling the adding proportion of the heneicosane to be 1%, placing a mixture in a heating container, heating to generate mixture steam at 200 ℃, setting the height of the steam to be 500mm, enabling atomized aluminum powder to freely fall, covering the aluminum powder with gas organic matters with the thickness of 300nm in the steam.

Step 4, freeze drying

Controlling the temperature of the drying oven to be 10 ℃, and collecting aluminum powder.

The D50 value of the aluminum powder granularity is 38um through detection, the oxygen content is tested to be 240ppm after the aluminum powder is placed in the air for 72h, the powder is pressed into a green body, then the green body is sintered for 30min in a nitrogen atmosphere at 500 ℃, the impurity content is tested to be equivalent to that of the powder, the oxygen content in the sintered aluminum block is 250ppm, and the problem of oxygen increasing hardly occurs in the subsequent use process.

Example 3

Preparing low-oxygen Al-Si12 alloy powder, which comprises the following steps:

step 1, vacuum melting

Adding pure aluminum ingot and aluminum-silicon intermediate alloy into a melting crucible according to a designed proportion, and vacuumizing to 5 x 10 ^-3 Pa, heating to 800 ℃ to melt.

Step 2, inert gas atomization

After the alloy is melted, 99.995% nitrogen is adopted to atomize the aluminum liquid into aluminum powder with D50 being 60um under the condition that the pressure is 2 Mpa.

Step 3, coating the gaseous organic matter

N-heneicosane and cyclododecane are used as raw materials, the adding proportion of the heneicosane is 0.5 percent, the mixture is placed in a heating container, mixture steam with the temperature of 150 ℃ is generated by heating, the height of the steam is set to be 300mm, and the atomized aluminum powder is freely fallen, passes through the steam and is coated with a gas organic layer with the thickness of 200 nm.

Step 4, freeze drying

Controlling the temperature of the drying oven at-20 ℃, and collecting aluminum powder.

The D50 value of the aluminum powder particle size is 38um through detection, and the oxygen content is 220ppm after the aluminum powder is placed in the air for 72 hours. The powder is subjected to 3D printing and forming under the inert gas condition to form a block material, and the oxygen content of the block material is detected to be 220ppm, and the oxygen content is hardly increased.

Example 4

The preparation method of the low-oxygen Al-7Zn powder comprises the following specific steps:

step 1, vacuum melting

Adding pure aluminum ingots and zinc ingots into a melting crucible according to a designed proportion, and vacuumizing to 6.0 x 10 ^-3 Pa, heating to 900 ℃ to melt.

Step 2, inert gas atomization

After the alloy is melted, 99.995% argon is adopted to atomize the aluminum liquid into aluminum powder with D50 being 10um under the condition that the pressure is 3 Mpa.

Step 3, coating the gaseous organic matter

N-heneicosane and cyclododecane are used as raw materials, the adding proportion of the heneicosane is 0.3 percent, the mixture is placed in a heating container, mixture steam with the temperature of 170 ℃ is generated by heating, the height of the steam is set to be 350mm, and gas organic matters with the thickness of 250nm are coated on the free falling bodies of the atomized aluminum powder through the steam.

Step 4, freeze drying

Controlling the temperature of the drying oven to be 0 ℃, and collecting aluminum powder.

Through detection, the D50 value of the aluminum powder particle size is 10um, the thickness of the coated film layer is 100nm, and the oxygen content is 200ppm after the aluminum powder is placed in the air for 72 hours for detection.

Comparative example 1

The same atomization powder preparation process as in example 4 is adopted, but an organic coating process is not introduced, and the specific steps of preparing the Al-7Zn powder are as follows:

step 1, vacuum melting

Adding pure aluminum ingot and aluminum-zinc intermediate alloy into a melting crucible according to a designed proportion, and vacuumizing to 6.0 x 10 ^{- 3} Pa, heating to 900 ℃ to melt.

Step 2, inert gas atomization

After the alloy is melted, 99.995% argon is adopted to atomize the aluminum liquid into aluminum powder with D50 being 10um under the condition that the pressure is 3 Mpa.

Step 3, cooling and drying

Controlling the temperature of the drying oven to be 0 ℃, and collecting aluminum powder.

Through detection, the D50 value of the aluminum powder particle size is 10um, and the oxygen content is 550ppm after the aluminum powder is placed in the air for 72h, which is obviously higher than that of the aluminum alloy powder coated by the organic matter in the embodiment 4.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, it is intended that such changes and modifications be included within the scope of the appended claims and their equivalents.

Claims (10)

1. The preparation method of the low-oxygen aluminum and aluminum alloy powder is characterized by comprising the following steps of:

s1, adding elements into the aluminum ingot and the intermediate alloy, and smelting by a vacuum smelting method to obtain alloy melt;

s2, uniformly adding the alloy melt prepared in the S1 into a gas atomization chamber for atomization, and adjusting the atomization pressure of inert gas to prepare the required aluminum and aluminum alloy powder;

s3, coating an organic film on the surface of the S2 aluminum and aluminum alloy powder through a section of gaseous organic matter molecular layer at the tail end of the cooling flight of the aluminum and aluminum alloy powder prepared by atomization;

wherein the gaseous organic matter is a reducing organic matter and does not contain oxygen;

and S4, freeze drying the aluminum and aluminum alloy powder coated with the S3 to obtain the low-oxygen aluminum and aluminum alloy powder.

2. The method of claim 1, wherein in S3, when reacting with oxygen, the organic material has a higher reducibility than the aluminum and aluminum alloy powder.

3. The method of claim 1, wherein the organic substance in S3 is in a solid state at room temperature.

4. The method of claim 1, wherein the organic material in S3 is a mixture of n-heneicosane and cyclododecane.

5. The method of claim 4, wherein the cyclododecane is added in an amount of 0.1 to 1% by mass based on the mass of n-heneicosane in S3.

6. The method of claim 1, wherein the temperature of the gaseous organic substance in S3 is 120-200 ℃, and the temperature of the aluminum and aluminum alloy powder entering the molecular layer of the gaseous organic substance is less than 50 ℃.

7. The method of claim 1, wherein in S3, the thickness of the organic thin film is 100-300 nm.

8. The method for producing aluminum suboxide and aluminum alloy powder according to claim 1, wherein the degree of vacuum in the vacuum melting is 4 to 6.7X 10 in S1 ^-3 Pa, and the melting temperature is 700-1000 ℃.

9. The method for producing a low-oxygen aluminum and aluminum alloy powder according to claim 1, wherein the freeze-drying temperature in S4 is-30 to 10 ℃.

10. An apparatus for producing low-oxygen aluminum and aluminum alloy powder, comprising:

the outlet of the vacuum smelting furnace is communicated with the inlet of a gas atomization chamber, the outlet of the gas atomization chamber is communicated with the inlet of a gas organic matter coating chamber, and the outlet of the gas organic matter coating chamber is communicated with the inlet of a freeze drying chamber; further comprising:

the organic matter evaporating chamber, the organic matter gas of evaporation in the organic matter evaporating chamber pass through the admission line with gaseous organic matter tectorial membrane room intercommunication, the indoor material of gaseous organic matter tectorial membrane is discharged through ejection of compact pipeline and is circulated in stating the organic matter evaporating chamber.

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