Preparation method of multi-element in-situ co-coated core-shell powder for additive manufacturing

Abstract

The invention provides a preparation method of multi-element in-situ co-coated core-shell spherical powder for additive manufacturing, and belongs to the technical field of additive manufacturing, and the preparation method comprises the following steps: step S1, dissolving soluble salts of various elements in liquid, and fully dispersing and dissolving the soluble salts through stirring or ultrasonic treatment; s2, spherical metal powder is added and subjected to ultrasonic treatment, and it is ensured that the metal powder is evenly wetted; s3, the solid-liquid mixture is placed in a drying box to be dried, and dried powder is obtained; and S4, the dried composite powder is placed in a hydrogen tube furnace, multi-stage calcination reduction treatment is carried out, and the multi-element co-coated copper composite powder is obtained. According to the preparation method of the multi-element in-situ co-coated core-shell spherical powder for additive manufacturing, multiple types of elements can be introduced at a time, the problems of uneven element distribution and out-of-control morphology in a traditional mixing process can be effectively solved, and technical support is provided for high-performance modification of the powder for additive manufacturing.

Description

Technical Field

[0001] The present invention belongs to the field of powder preparation for additive manufacturing, and in particular relates to a method for preparing multi-element in-situ co-coated core-shell powder for additive manufacturing. Technical Background

[0002] Additive Manufacturing (AM), also known as 3D printing, is an innovative manufacturing process. This process uses computer-aided design (CAD) software to create a three-dimensional model, and uses specific printing technology to stack discrete materials (such as powder, liquid, filament, etc.) layer by layer to eventually form the required parts. Additive manufacturing integrates multiple disciplines such as information technology, new material technology and manufacturing technology. It is widely regarded as one of the most disruptive technologies in the 21st century and plays a key role in promoting the development of Industry 4.0. Specifically, compared with traditional metal manufacturing processes, additive manufacturing technology has significant advantages in material utilization, process simplification, design flexibility, complex structure manufacturing capabilities, intelligent implementation and production efficiency.

[0003] In additive manufacturing (AM), metal powder is a key raw material, and its properties have a direct and significant impact on the quality and performance of the resulting parts. Ideal metal powders require a fine and uniform particle size distribution, typically ranging from 15 to 150 microns. This particle size distribution ensures good flowability and uniform powder spreading, thereby improving the density of the resulting parts. Furthermore, the powder particles should be as close to spherical as possible to reduce defects during the forming process and enhance the surface quality and dimensional accuracy of the parts. Powders with high bulk density more effectively fill the forming space, thereby enhancing the mechanical properties of the parts. Furthermore, powders with low oxygen content and high purity effectively avoid defects caused by oxidation and impurities during the forming process, ensuring stable part performance. Powder uniformity and stability are also crucial, as they directly impact the consistency and reliability of the resulting part performance. Therefore, strict control of metal powder performance parameters such as particle size, morphology, bulk density, purity, flowability, sphericity, oxygen content, uniformity, and stability is crucial for the successful application of AM technology and the production of high-quality parts.

[0004] Currently, additive manufacturing processes primarily use physical methods such as ball milling or mechanical stirring to mix elemental powders with metal powders. For example, Patent No. CN119159099A discloses a method for preparing LaB6 and Cr2Nb synergistically reinforced copper-based composites. The composite powder is prepared by mechanically ball milling LaB6 powder and CuCrNb powder. However, these methods are prone to introducing impurities, disrupting the sphericity of the powders, and causing elemental particle agglomeration, which is detrimental to powder flowability and elemental distribution uniformity during LPBF processes. Furthermore, a study published in Nature titled "3D printing of high-strength thaluminium alloys" proposed a method for combining alloy powders with nanoparticles through electrostatic assembly, successfully producing a powder feedstock with a uniform nanoparticle distribution. However, these methods only involve the introduction of a single type of material and cannot simultaneously achieve uniform distribution of multiple elements or materials. Based on this, the present invention develops a method for preparing multi-element in-situ co-coated core-shell powders for additive manufacturing, which has important engineering significance. This method can achieve uniform distribution of multiple elements while ensuring high purity and high sphericity of the powder, effectively filling this blank area. Summary of the Invention

[0005] The present invention addresses the bottlenecks of single element introduction and impaired sphericity in the prior art, and provides a method for preparing multi-element in-situ co-coated core-shell powders for additive manufacturing, so as to ensure the high purity, high sphericity and uniform distribution of elements of the powder, thereby achieving uniform introduction of multiple elements.

[0006] The main steps of the present invention are as follows:

[0007] Step S1, dissolving soluble salts of multiple elements in a liquid to fully dissolve them;

[0008] Step S2, adding spherical metal powder to fully wet it;

[0009] Step S3, drying the solid-liquid mixture in a drying oven to obtain dry powder;

[0010] Step S4: placing the composite powder in a hydrogen tubular furnace, and subjecting it to multi-stage calcination and reduction treatment to obtain a multi-element co-coated copper composite powder.

[0011] Furthermore, in step S1, the multiple types of elemental soluble salts are nitrates, sulfates, chlorides, ammonium paratungstate, and the like.

[0012] Furthermore, in step S1, the liquid is ethanol or distilled water.

[0013] Furthermore, in step S1, the dissolution process is stirring or ultrasonic treatment.

[0014] Furthermore, in step S2, the spherical metal powder is Cu, CuCrZr or CuCrNb, etc.

[0015] Furthermore, in step S2, the wetting process is stirring or ultrasonic treatment.

[0016] Furthermore, in step S3, the drying temperature is 60-80°C, and the drying time is 3-6 hours.

[0017] Furthermore, in step S4, the multi-stage calcination and reduction process refers to keeping the temperature at 300°C, 400°C, 500°C, 600°C, 700°C and 850°C for 1 to 2 hours respectively.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The process of the present invention is simple, does not produce any extra products, and can ensure the high purity of the prepared powder.

[0020] 2. The present invention can realize the one-time co-introduction of multiple elements and ensure uniform distribution, so that the prepared composite powder has high sphericity and high fluidity, which meets the requirements of additive manufacturing process.

[0021] 3. The present invention can achieve precise control of the content of the added elements and can prepare multi-element coated composite powders with different contents. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 : (a) SEM image of the composite powder prepared in Example 1 and the corresponding (b) W and (c) Cr elemental energy spectrum scan images;

[0023] Figure 2 : (a) SEM image of the composite powder prepared in Example 2 and the corresponding (b) Zr and (c) Cr elemental energy spectrum scan images;

[0024] Figure 3 : (a) SEM image of the composite powder prepared in Example 3 and the corresponding (b) Zr and (c) Ti elemental energy spectrum scan images;

[0025] Figure 4 : (a) SEM image of the composite powder prepared in Example 4 and the corresponding (b) Cr, (c) Zr and (d) W elemental energy spectrum scan images;

[0026] Figure 5 : (a) SEM image of the composite powder prepared in Example 5 and the corresponding (b) Ti, (c) Cr, (d) Zr and (e) W element energy spectrum scan images. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] An embodiment of the present invention provides a method for preparing a multi-element in-situ co-coated core-shell powder for additive manufacturing, comprising the following steps:

[0030] Step S1, dissolving chromium nitrate and ammonium paratungstate in ethanol and fully dissolving them by ultrasonic treatment;

[0031] Step S2, adding spherical Cu powder and performing ultrasonic treatment to ensure that the metal powder is completely wetted;

[0032] Step S3, drying the solid-liquid mixture in a drying oven at 80°C for 6 hours;

[0033] In step S4, the composite powder is placed in a hydrogen tubular furnace and heated to 850°C in multiple stages for calcination and reduction. The heating program is as follows: 300°C, 400°C, 500°C, 600°C, 700°C, and 850°C, each held for 1 hour. To obtain a W-Cu-Cr powder with a weight ratio of 50:46:4, the weight ratio of ammonium paratungstate, copper, and chromium nitrate is 56.5:46:18.3.

[0034] Figure 1 The microstructure and elemental energy spectrum of the prepared W-Cu-Cr powder are presented. The results show that the W-Cu-Cr powder maintains high sphericity and has a uniform distribution of W and Cr elements, achieving the introduction of 50wt.% W and 4wt.% Cr.

[0035] Example 2

[0036] An embodiment of the present invention provides a method for preparing a multi-element in-situ co-coated core-shell powder for additive manufacturing, comprising the following steps:

[0037] Step S1, dissolving zirconium nitrate and chromium sulfate in distilled water and fully dissolving them by ultrasonic treatment;

[0038] Step S2, adding spherical CuCrZr alloy powder and stirring to ensure that the metal powder is completely wetted;

[0039] Step S3, drying the solid-liquid mixture in a drying oven at 60°C for 3 hours;

[0040] In step S4, the composite powder is placed in a hydrogen tubular furnace and heated to 850°C in multiple stages for calcination and reduction. The heating program is: 300°C, 400°C, 500°C, 600°C, 700°C, and 850°C, each for 1.5 hours.

[0041] Figure 2 The microstructure and elemental spectrum of the prepared composite powder are shown. SEM and energy spectrum analysis show that the prepared powder maintains high sphericity and achieves uniform distribution of Cr and Zr elements.

[0042] Example 3

[0043] An embodiment of the present invention provides a method for preparing a multi-element in-situ co-coated core-shell powder for additive manufacturing, comprising the following steps:

[0044] Step S1, dissolving titanium sulfate and zirconium nitrate in distilled water and stirring to fully dissolve them;

[0045] Step S2, adding spherical Cu powder and performing ultrasonic treatment to ensure that the metal powder is completely wetted;

[0046] Step S3, drying the solid-liquid mixture in a drying oven at 80°C for 3 hours;

[0047] In step S4, the composite powder is placed in a hydrogen tubular furnace and heated to 850°C in multiple stages for calcination and reduction. The heating program is as follows: 300°C, 400°C, 500°C, 600°C, 700°C, and 850°C, each held for 2 hours. To obtain a Cu-Ti-Zr powder with a weight ratio of 70:26:4, the weight ratio of copper, titanium sulfate, and zirconium nitrate is 4.70:8.76:1.

[0048] Figure 3 The microstructure and elemental energy spectrum of the prepared Cu-Ti-Zr powder are shown. SEM and energy spectrum analysis show that the Cu-Ti-Zr powder maintains high sphericity and uniform distribution of Ti and Zr elements, successfully achieving the introduction of 26wt.% Ti and 4wt.% Zr.

[0049] Example 4

[0050] An embodiment of the present invention provides a method for preparing a multi-element in-situ co-coated core-shell powder for additive manufacturing, comprising the following steps:

[0051] Step S1, dissolving chromium nitrate, zirconium chloride and ammonium paratungstate in ethanol and fully dissolving them by ultrasonic treatment;

[0052] Step S2, adding spherical CuCrNb powder and performing ultrasonic treatment to ensure that the metal powder is completely wetted;

[0053] Step S3, drying the solid-liquid mixture in a drying oven at 80°C for 6 hours;

[0054] In step S4, the composite powder is placed in a hydrogen tubular furnace and heated to 850°C in multiple stages for calcination and reduction. The heating program is: 300°C, 400°C, 500°C, 600°C, 700°C, and 850°C, each for 2 hours.

[0055] Figure 4 The microstructure and elemental energy spectrum of the prepared composite powder are shown. SEM and energy spectrum analysis show that the composite powder maintains high sphericity and achieves uniform distribution of the three elements W, Cr, and Zr.

[0056] Example 5

[0057] An embodiment of the present invention provides a method for preparing a multi-element in-situ co-coated core-shell powder for additive manufacturing, which comprises the following steps:

[0058] Step S1, dissolving chromium nitrate, titanium nitrate, zirconium chloride and ammonium paratungstate in ethanol and fully dissolving them by ultrasonic treatment;

[0059] Step S2, adding spherical CuCrNb powder and performing ultrasonic treatment to ensure that the metal powder is completely wetted;

[0060] Step S3, drying the solid-liquid mixture in a drying oven at 80°C for 6 hours;

[0061] Step S4, placing the composite powder in a hydrogen tubular furnace, heating it to 850°C in multiple stages for calcination and reduction treatment (keeping it at 300°C, 400°C, 500°C, 600°C, 700°C and 850°C for 2 hours each).

[0062] Figure 5 The microstructure and elemental energy spectrum of the prepared composite powder are displayed. The results show that the composite powder maintains high sphericity and achieves uniform distribution of the four elements W, Ti, Cr, and Zr.

[0063] The present invention has been described in detail above through the embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The scope of protection of the present invention is defined by the claims. Any use of the technical solution described in the present invention, or any person skilled in the art who, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and scope of protection of the present invention to achieve the above-mentioned technical effects, or any equivalent changes and improvements made to the scope of application, shall still fall within the scope of protection covered by the patent of the present invention.

Claims

1. A method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing, characterized in that: The following steps are involved: Step S1, dissolving soluble salts of multiple elements in a liquid and allowing them to fully dissolve; Step S2, adding spherical metal powder and making it completely wet; Step S3, drying the solid-liquid mixture in a drying oven to obtain dry powder; Step S4: placing the composite powder in a hydrogen tubular furnace, and subjecting it to multi-stage calcination and reduction treatment to obtain a multi-element co-coated copper composite powder.

2. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S1, the various types of elemental soluble salts are nitrates, sulfates, chlorides, ammonium paratungstate, and the like.

3. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S1, the liquid is ethanol or distilled water.

4. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S1, the dissolution process is stirring or ultrasonic treatment.

5. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S2, the spherical metal powder is Cu, CuCrZr or CuCrNb, etc.

6. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S2, the wetting process is stirring or ultrasonic treatment.

7. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S3, the drying temperature is 60-80° C., and the drying time is 3-6 hours.

8. The method for preparing multi-element in-situ co-coated core-shell spherical powder for additive manufacturing according to claim 1, characterized in that: In step S4, the multi-stage calcination and reduction process refers to keeping the temperature at 300°C, 400°C, 500°C, 600°C, 700°C and 850°C for 1 to 2 hours respectively.

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