Method for preparing metal powder in batches through complex fluid atomization technology

Abstract

The invention discloses a method for preparing metal powder in batches through a complex fluid atomization technology. The method comprises the following steps: 1) regulating the physicochemical properties of a mixture by changing the composition, temperature and pressure of the mixture to obtain a required complex fluid; the mixture is selected from at least two of water, an organic compound, a surfactant, gas, ionic liquid and inorganic salt; (2) the complex fluid is used for crushing molten metal through a fluid atomization method; and (3) after the complex fluid in the step (2) is atomized, powder and the fluid are separated through a filtering method, and the metal powder is obtained after the powder is washed and dried. According to the method, batch preparation of the light metal powder can be achieved, and the requirements of 3D printing and MIM are met. The particle size, sphericity and non-metallic element content of the powder can be regulated and controlled by selecting proper fluid, so that batch production of 3D printing powder and MIM powder meeting different requirements can be realized by selecting different fluids.

Description

Technical Field

[0001] The invention belongs to the field of material synthesis and relates to a method for preparing metal powder in batches by using complex fluid atomization technology. Background Art

[0002] Lightweight metals and their alloys have poor machinability. Traditional machining methods require expensive equipment and low machining efficiency, which greatly increases their machining costs. The structure of machined lightweight metal parts is usually simple, and due to the limitations of the machining method, most of them cannot achieve a design that can bring out the best performance of the material. In this context, metal powder 3D printing and injection molding (MIM) processes, which have the advantages of high raw material utilization and low mass production costs, have become ideal processing technologies for lightweight metals and their alloys, and can well achieve the characteristics of lightweight parts, high precision, high strength, and high friction coefficient.

[0003] Lightweight metals such as aluminum or aluminum alloys, magnesium or magnesium alloys, titanium or titanium alloys, lithium or lithium alloys have the characteristics of low specific gravity, high specific strength, good corrosion resistance, etc., and have great application potential in high-end 3C electronic products, aerospace, biomedicine, chemical industry, automobiles, etc. 3D printing technology or MIM technology can realize the mass and low-cost preparation of small and medium-sized complex-shaped lightweight metal products, which is of great significance to promote the production and application of lightweight metal and alloy parts.

[0004] In order to meet the mechanical properties of high-end parts, metal powders must meet indicators such as particle size, sphericity, and non-metallic element content. Compared with 3D printing powders, MIM powders have higher index requirements. The particles obtained by the traditional gas atomization method are large in size and have a low yield rate. Although the water atomization method can achieve a higher yield rate, it will lead to a significant increase in hydrogen and oxygen content, and it is impossible to obtain metal powder materials that meet the production requirements of high-end parts. Complex fluids are solution systems composed of different media. By adjusting the solution composition, solution temperature, and solution phase, the properties of the solution can be fully regulated. By designing complex fluids and changing the fluid components and properties, batch preparation of metal powders that meet the needs of different industries can be achieved. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing metal powder in batches by using complex fluid atomization technology.

[0006] The present invention provides a method for batch preparation of metal powders using complex fluid atomization technology, comprising the following steps:

[0007] 1) Modulate the physical and chemical properties of the mixture by changing its composition, temperature and pressure to obtain the desired complex fluid;

[0008] The mixture is selected from at least two of water, an organic compound, a surfactant, a gas, an ionic liquid and an inorganic salt;

[0009] 2) crushing the molten metal by atomizing the complex fluid;

[0010] 3) After the complex fluid in step 2) is atomized, the powder is separated from the fluid by filtering, and the powder is washed and dried to obtain metal powder.

[0011] In the above method, the organic compound is selected from at least one of methanol, ethanol, cyclohexane, carbon tetrachloride, octane, decane and dodecane;

[0012] The surfactant may be selected from at least one of hexadecyltrimethylammonium bromide, sodium hexadecyl sulfonate, disodium lauryl sulfosuccinate, and potassium monododecyl phosphate;

[0013] The gas is selected from at least one of carbon dioxide, nitrogen, argon, ethylene, ethane, propylene and propane;

[0014] The ionic liquid may be selected from imidazolium ionic liquids, wherein the anion of the imidazolium ionic liquid is selected from at least one of halogen, tetrafluoroborate and hexafluorophosphate;

[0015] The inorganic salt may be selected from at least one of sulfites, citrates and sulfides, and may specifically be sodium sulfite.

[0016] In the above method, the ionic liquid may be C n mimBr or C n mimBF 4 , wherein n=an integer from 2 to 16.

[0017] In the above method, the state of the complex fluid is regulated to be gaseous, liquid or supercritical by changing the composition, temperature and pressure of the mixture.

[0018] In the present invention, the complex fluid is formulated according to the target product.

[0019] In the above method, in step 2), the flow rate and pressure of the fluid atomization method are controlled by a circulation pump;

[0020] The flow rate of the fluid may be 0 to 300 L / min;

[0021] The pressure may be 0 to 150 MPa.

[0022] In the above method, the solvent used for washing can be at least one of N,N-dimethylformamide, acetone, ethanol and water;

[0023] The drying is vacuum drying at 60-100° C. for 12-48 hours, specifically vacuum drying at 60° C. for 24 hours.

[0024] In the above method, step 3) further comprises recycling the separated fluid;

[0025] Step 3) also includes screening the dried powder by sieve screening or air flow classification screening to obtain a powder material that meets the particle size requirements.

[0026] In the above method, the metal powder prepared by the method is powder for 3D printing and MIM powder.

[0027] In the above method, the MIM powder may be 0 to 25 μm, and the 3D printed powder may be 10 to 63 μm.

[0028] The present invention has the following beneficial effects:

[0029] The method of the present invention can realize the batch preparation of lightweight metal powders to meet the needs of 3D printing and MIM. The particle size, sphericity, and non-metallic element content of the powder can be regulated by selecting a suitable fluid, so the batch production of 3D printing powders and MIM powders that meet different requirements can be achieved by selecting different fluids. Through fluid atomization technology, the material yield rate and component quality can be greatly improved, and the fluid has low loss, can be recycled, and does not discharge three wastes, which is a new green and sustainable path. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a scanning electron microscope image of 3D printed aluminum alloy powder.

[0031] Figure 2 This is a scanning electron microscope image of MIM titanium alloy powder. DETAILED DESCRIPTION

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0033] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0034] The present invention provides a method for batch preparing metal powders using complex fluid atomization technology, comprising the following steps:

[0035] 1) Modulate the physical and chemical properties of the mixture by changing its composition, temperature and pressure to obtain the desired complex fluid;

[0036] The mixture is selected from at least two of water, an organic compound, a surfactant, a gas, an ionic liquid and an inorganic salt;

[0037] 2) crushing the molten metal by atomizing the complex fluid;

[0038] 3) After the complex fluid in step 2) is atomized, the powder is separated from the fluid by filtering, and the powder is washed and dried to obtain metal powder.

[0039] Example 1: Preparation of 3D printed aluminum alloy powder

[0040] (I) Complex fluid preparation: Mix water, hexadecyltrimethylammonium bromide and sodium sulfite in a mass ratio of 9.5:0.05:0.45 to form a uniform solution.

[0041] (ii) Fluid property regulation: adjust the fluid temperature to 25 degrees Celsius and the pressure to 0.1 MPa.

[0042] (III) Complex fluid atomization: 1300L of fluid is loaded into the tank and pumped out by a pump at a flow rate of 30L / min and an outlet pressure of 40Mpa. 5kg of aluminum alloy bars are melted at high temperature, and the molten slurry is impacted by the fluid during its fall. The whole process is carried out under the protection of argon atmosphere.

[0043] (IV) Powder screening: The obtained aluminum alloy powder is separated from the fluid by filtering. The powder is washed and dried to obtain the product, and the fluid is recovered to the storage tank. The powder is screened by mesh and air flow classification to select powder with a size of 10 to 63 μm, which is the 3D printing aluminum alloy powder. Its microscopic morphology is as follows: Figure 1 The yield of 3D printed aluminum alloy powder prepared by this method is 20% to 60% (specifically 56% in one experiment).

[0044] Example 2: Preparation of MIM titanium alloy powder

[0045] (I) Complex fluid preparation: Methanol, C 8 MimBr and ethylene were mixed in a mass ratio of 9.5:0.4:0.1.

[0046] (ii) Fluid property regulation: adjust the fluid temperature to 350 degrees Celsius and the pressure to 9 MPa.

[0047] (III) Complex fluid atomization: 1300L of fluid is put into the tank and pumped out by a pump with a flow rate of 100L / min and an outlet pressure of 80Mpa. 5kg of titanium alloy rod is melted at high temperature, and the molten slurry is impacted by the fluid during its falling process. The whole process is carried out under the protection of argon atmosphere.

[0048] (IV) Powder screening: The obtained titanium alloy powder is separated from the fluid by filtering. The powder is washed and dried to obtain the product, and the fluid is recovered to the storage tank. The powder is screened by air flow classification to select the powder with a size of 0 to 20 μm, which is the MIM titanium alloy powder. Its microscopic morphology is as follows: Figure 2 The yield of MIM titanium alloy powder prepared by this method is 50% to 90% (specifically 85% in one experiment).

[0049] Without departing from the spirit and essence of the present invention, any modification or substitution of the methods, steps or conditions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for batch preparation of metal powders using complex fluid atomization technology, comprising the following steps: 1) Modulate the physical and chemical properties of the mixture by changing its composition, temperature and pressure to obtain the desired complex fluid; The mixture is selected from at least two of water, an organic compound, a surfactant, a gas, an ionic liquid and an inorganic salt; 2) crushing the molten metal by atomizing the complex fluid; 3) After the complex fluid in step 2) is atomized, the powder is separated from the fluid by filtering, and the powder is washed and dried to obtain metal powder.

2. The method according to claim 1, characterized in that The organic compound is selected from at least one of methanol, ethanol, cyclohexane, carbon tetrachloride, octane, decane and dodecane; The surfactant is selected from at least one of hexadecyltrimethylammonium bromide, sodium hexadecyl sulfonate, disodium lauryl sulfosuccinate, and potassium monododecyl phosphate; The gas is selected from at least one of carbon dioxide, nitrogen, argon, ethylene, ethane, propylene and propane; The ionic liquid is selected from imidazolium ionic liquids, and the anion of the imidazolium ionic liquid is selected from at least one of halogen, tetrafluoroborate and hexafluorophosphate; The inorganic salt is selected from at least one of sulfites, citrates and sulfides.

3. The method according to claim 1 or 2, characterized in that: The ionic liquid is C n mimBr or C n mimBF4, wherein n=an integer from 2 to 16.

4. The method according to any one of claims 1 to 3, characterized in that The mixture can regulate the state of the complex fluid to be gaseous, liquid or supercritical by changing the composition, temperature and pressure.

5. The method according to any one of claims 1 to 4, characterized in that In step 2), the flow rate and pressure of the fluid atomization method are controlled by a circulating pump; The flow rate of the fluid is 0 to 300 L / min; The pressure is 0-150 MPa.

6. The method according to any one of claims 1 to 5, characterized in that The washing solvent is at least one of N,N-dimethylformamide, acetone, ethanol and water; The drying is performed under vacuum at 60 to 100° C. for 12 to 48 hours.

7. The method according to any one of claims 1 to 6, characterized in that Step 3) also includes recycling the separated fluid; Step 3) also includes screening the dried powder by sieve screening or air flow classification screening to obtain a powder material that meets the particle size requirements.

8. The method according to any one of claims 1 to 7, characterized in that The metal powder prepared by the method is powder for 3D printing and MIM powder.

9. The method according to claim 8, characterized in that The MIM powder is 0-25 μm, and the 3D printed powder is 10-63 μm.

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