Coated powder for ultra-high-speed laser metal 3D printing, preparation and printing method

Abstract

This application relates to the field of additive manufacturing technology, and particularly to a coating powder for ultra-high-speed laser metal 3D printing, its preparation, and a printing method. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The organic coating layer has the following weight proportions: rigid polymer backbone: 35-70 parts; polymer containing coordinating groups: 10-30 parts; soluble pore-forming agent: 10-30 parts; lubricant: 5-15 parts; leveling agent: 0.5-2 parts; antioxidant: 0.5-3 parts; defoamer: 0.5-2 parts; antistatic agent: 0.5-2 parts. By co-coating the surface of the metal powder with the polymer containing coordinating groups and the soluble pore-forming agent, a composite coating layer that functions as both a reaction site and a sacrificial template is constructed. This solves the problems of low green strength, uncontrollable pore structure, difficulty in functional modification, incompatibility with traditional binder systems, and complex post-processing in existing technologies.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to a coating powder for ultra-high-speed laser metal 3D printing, its preparation and printing method. Background Technology

[0002] Metal 3D printing technology, especially ultra-high-speed laser metal 3D printing represented by laser powder bed melting and laser powder bed sintering, has become a key manufacturing technology in high-end fields such as aerospace, biomedicine, and automotive manufacturing due to its superior forming accuracy, efficient near-net-shape forming capability, and freedom in manufacturing complex geometries. This technology selectively melts metal powder with a high-energy laser beam, depositing it layer by layer to form a three-dimensional solid structure.

[0003] However, in the pursuit of higher precision, more complex structures, and wider functional applications, existing technologies face a series of fundamental technical bottlenecks determined by the material system and process logic itself, specifically in the following aspects: (1) Insufficient green strength: The green strength formed by conventional metal powder after laser scanning is extremely low, usually less than 1MPa, which is difficult to support complex overhanging structures or fine features, resulting in easy deformation and collapse during printing, which seriously restricts printing accuracy and structural complexity. (2) Pore structure is difficult to control: Metal 3D printed parts usually pursue high density, but in application scenarios such as bone implants, catalyst carriers, and porous electrodes, the parts need to have specific pore structures to promote bone ingrowth, increase specific surface area, or realize material transport. Existing technologies mainly introduce pores through two approaches: one is to adjust the laser process parameters to intentionally create incomplete fusion, but the pores formed by this method are random and uncontrollable, and seriously sacrifice the mechanical integrity of the parts; the other is to directly mix inorganic or polymer pore-forming agents into metal powder, and leave pores by decomposing them through heat treatment after printing. However, the thermal decomposition behavior of pore-forming agents is violent, and the generated gas will form high pressure inside the dense green body, which can easily cause bubbling, cracking, or even structural collapse of the parts during the debinding / sintering stage, resulting in a low yield. (3) Difficulty in functional modification: To endow metal parts with bioactivity, catalytic function or other special properties, it is often necessary to introduce functional components after they are formed. Existing methods mostly modify the parts by surface coating or impregnation after the parts are fully densified. The functional substances can only stay on the surface and are difficult to penetrate into the interior of the parts. For example, using hydrogels with ion coordination ability as precursors, metal structures can be indirectly prepared by 3D printing, freeze drying, ion impregnation and heat treatment conversion. Although this method shows the possibility of introducing functional ions into materials, its process path is extremely long, and the low modulus of the hydrogel precursors leads to limited structural resolution in the printing. Significant shrinkage and deformation are prone to occur during drying and heat treatment, making it difficult to guarantee the dimensional accuracy and integrity of the complex structure of the final metal parts. (4) Limitations of existing binder systems: Most binder systems used in metal 3D printing are directly adopted from metal injection molding technology, with polyoxymethylene and other materials as rigid skeletons, supplemented by various additives. The core of its design is to optimize the rheological properties of the feed material to adapt to injection molding and ensure the smooth progress of catalytic debinding. However, MIM process and laser powder bed 3D printing are fundamentally different in physical process: the former is viscous fluid filling under high pressure, while the latter is selective laser melting and layer stacking in a powder bed; more importantly, the design concept of MIM binder does not involve molecular design to reserve reaction sites for subsequent functional modification, so it is difficult to meet the manufacturing needs of the next generation of functional metal parts; (5) Complex post-processing: In order to improve the strength of the green blank or introduce functional materials, existing technologies often use complex post-processing processes such as high-temperature sintering and chemical treatment, which not only consume a lot of energy and have a long cycle, but may also cause parts to deform or degrade in performance.

[0004] Therefore, how to design a multifunctional coating powder that can meet the requirements of laser 3D printing process, improve green strength, programmable control of pore structure, and introduce functional components in situ, and establish a matching printing and post-processing process, has become a core technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This application provides a coating powder for ultra-high-speed laser metal 3D printing, its preparation and printing method, to solve the problems of low green strength, uncontrollable pore structure, difficulty in functional modification, mismatch with traditional binder systems, and complex post-processing in the prior art.

[0006] This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportions of the organic coating layer include: Rigid polymer skeleton: 35-70 parts; Polymers containing coordinating groups: 10-30 parts; Soluble porogen: 10-30 parts; Lubricant: 5-15 parts; Leveling agent: 0.5-2 parts; Antioxidant: 0.5-3 parts; Defoaming agent: 0.5-2 parts; Antistatic agent: 0.5-2 parts.

[0007] Optionally, the metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0008] Optionally, the rigid polymer backbone is selected from at least one of homopolymer polyacetal and copolymer polyacetal, and the coordinating group is selected from at least one of carboxyl, amino, and pyridyl groups.

[0009] Optionally, the soluble porogen is polymethyl methacrylate microspheres, polystyrene microspheres, or polyacrylate microspheres, with a particle size distribution D50 of 5-30 μm.

[0010] Optionally, the lubricant is selected from at least one of paraffin wax, polyethylene wax, and stearic acid; the antioxidant is selected from at least one of hindered phenolic antioxidants and phosphite antioxidants; the defoamer is selected from at least one of polysiloxane defoamers and non-silicone defoamers; the leveling agent is selected from at least one of acrylate leveling agents and organosilicon leveling agents; and the antistatic agent is selected from at least one of ethoxylated fatty amine antistatic agents and glyceryl monostearate antistatic agents.

[0011] It should be noted that the acrylic leveling agent is BYK-354 or BYK-355, the silicone leveling agent is BYK-310 or BYK-333, the polysiloxane defoamer is BYK-A530 or BYK-A535, the non-silicone defoamer is BYK-051 or BYK-052, the ethoxylated fatty amine antistatic agent is Atmer163 or Atmer129, and the glyceryl monostearate antistatic agent is Atmer122 or Atmer125.

[0012] The introduction of antistatic agents in the embodiments of this application can effectively reduce the electrostatic agglomeration of powder during the powder spreading process and improve the uniformity of the printed layer; lubricants and leveling agents work together to improve the surface quality of the coating layer; antioxidants and defoamers ensure the thermal stability during melt blending and printing. Although these additives do not directly participate in the subsequent functionalization reaction, they play an important role in ensuring the printing performance and process stability of the coated powder.

[0013] Optionally, the mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 5:1 to 1:1.

[0014] This application also provides a method for preparing coated powder for ultra-high-speed laser metal 3D printing, including the following steps: S1. Add the rigid polymer backbone, polymer containing coordinating groups, soluble pore-forming agent, lubricant, leveling agent, antioxidant, defoamer and antistatic agent into a high-speed mixer according to the ratio, and mix at 500-1500 rpm for 5-15 minutes at room temperature to obtain organic binder premix; S2. Add the organic binder premix obtained in step S1 into a twin-screw extruder. The screw speed of the twin-screw extruder is 100-300 rpm, and the extrusion temperature from the feeding section to the die head is 160-180℃, 180-200℃, 200-220℃, and 200-220℃ respectively. Melt blend at 160-220℃, extrude and granulate to obtain organic binder particles. S3. The organic binder particles obtained in step S2 are crushed in a low-temperature pulverizer, sieved, and organic binder powder with a particle size of 5-30μm is selected. S4. Add the metal powder and the organic binder powder obtained in step S3 into a three-dimensional mixer according to the ratio, and mix at 50-200 rpm for 30-90 minutes at room temperature to make the organic binder powder uniformly coat the surface of the metal powder, so as to obtain the coating powder for ultra-high speed laser metal 3D printing.

[0015] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide the aforementioned coating powder; S2. Using powder bed laser melting or laser powder bed sintering processes, 3D printing is performed with parameters of laser power 200-1000W, scanning speed 500-3000mm / s, and layer thickness 20-60μm, layer by layer to form a printed green body with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 0.1-2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing the coordinating group to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0016] Optionally, in step S3, the cleaning solvent is selected from at least one of water, ethanol, and acetone, the cleaning temperature is 20-60℃, and the cleaning time is 1-24 hours; in step S4, the polyvalent metal ion is selected from Fe. 3+ Al 3+ Cu 2+ Zn 2+ Ca 2+ At least one of the following, the soaking time is 2-48 hours.

[0017] Optionally, in step S5, the catalytic degreasing temperature is 80-150℃, and the holding time is 2-6 hours; the vacuum sintering temperature is 1100-1400℃, and the holding time is 2-4 hours.

[0018] Therefore, this application has at least the following beneficial effects: (1) This invention is the first to co-coat the surface of metal powder with a polymer containing carboxyl, amino, or pyridine groups and a soluble pore-forming agent, forming a composite coating layer with dual functions of reaction sites and sacrificial templates. In this process, the carboxyl groups densely distributed on the polymer molecular chains containing coordinating groups coordinate and chelate with polyvalent metal ions during subsequent ionic crosslinking treatment, forming a stable coordination crosslinking network. This constructs a three-dimensional reinforcing skeleton inside the green body, significantly improving the strength of the green body. The soluble pore-forming agent is selectively dissolved and removed by solvent after printing, forming interconnected micron-sized pores, achieving rapid and thorough dissolution. Unlike thermal decomposition pore-forming, the solvent pore-forming process is mild and gas-free, avoiding problems such as bubbling and cracking caused by traditional thermal decomposition. The porosity can be precisely controlled within the range of 15%-60%. More importantly, the interconnected pores formed by the dissolution of the pore-forming agent provide a smooth diffusion channel for the subsequent ionic solution, allowing metal ions to be drawn into the pores through capillary action, achieving uniform penetration and improving crosslinking efficiency.

[0019] (2) In this invention, the 1-50μm interconnected micron-level pores formed after the pore-forming agent dissolves constitute a three-dimensional capillary network. According to the capillary rise formula, the smaller the pore size, the greater the capillary rise height, which can quickly draw the metal ion solution into the pores. After the metal ions enter the pores, they diffuse into the pore wall under the drive of the concentration gradient according to the Fick diffusion law. At the same time, the polymer molecular chains containing coordination groups swell and expose the coordination groups. The metal ions and coordination groups undergo coordination reactions according to the ligand field theory to form stable coordination bonds. The coupling of diffusion and reaction enables the cross-linking network to be gradually built from the pore wall inward, forming a gradient-enhanced structure. With the help of the coupling mechanism of capillary diffusion and coordination reaction, uniform loading and efficient cross-linking of metal ions are achieved. In addition, by controlling the metal ion concentration in the range of 0.1-2.0mol / L and the soaking time of 2-48 hours, the coordination reaction rate and cross-linking density can be controlled according to the Langmuir adsorption isotherm, thereby improving the green strength and fundamentally avoiding bubbling, expansion and cracking caused by gas retention.

[0020] (3) In the embodiments of this application, the micron-sized main channels are formed through a template replication mechanism, that is, the cavity left after the soluble porogen dissolves is retained as a "negative template" during the sintering process. The appropriate sintering temperature can make the densification rate moderate, thereby retaining the channel structure, and the channel size is highly correlated with the particle size of the porogen. The submicron-sized network pores are formed through a pyrolysis-induced phase separation mechanism. The polymer containing coordination groups undergoes thermal decomposition during catalytic degreasing and sintering, and its decomposition products remain in the form of carbon skeletons. These carbon skeletons are wrapped during the growth of metal grains. Based on the principle of "sintering resistance", the carbon skeletons are pinned at the grain boundaries, inhibiting grain growth and pore healing, thereby forming submicron-sized network pores. The micron-sized main channels can provide a fast channel for material transport, and the submicron-sized network pores can provide a high specific surface area. The synergistic effect of the two types of pores makes the material have both excellent mass transfer performance and surface activity, which is particularly suitable for implants that require bone ingrowth or catalytic carriers with high specific surface area.

[0021] (4) This invention achieves decoupled control of green strength and sintering densification through the synergistic effect of ionic crosslinking and catalytic debinding. The coordination network formed by ionic crosslinking significantly improves the green modulus based on polymer network theory, providing structural support for subsequent processing. During catalytic debinding, the acidic catalyst follows the "core retreat" model to catalyze polymer depolymerization layer by layer from the surface to the inside, avoiding internal pressure accumulation and ensuring the shape stability of the parts during debinding. In the subsequent vacuum sintering stage, the grain growth kinetics are regulated by precisely controlling the sintering temperature and time, effectively preserving submicron-level pores while achieving metal powder necking and densification, thus achieving a good balance between high strength and high porosity in the final parts.

[0022] (5) This invention breaks through the traditional technical paradigm of using carboxyl groups and other coordinating groups in the polymer backbone, which is a one-time sacrificial phase for metal injection molding binders, and opens up a new path for programmable functionalization. Specifically, the dense carboxyl groups pre-placed on the polymer chain serve as reaction sites and are activated and exposed after solvent pore formation; multivalent metal ions are stablely anchored in the polymer network through diffusion to undergo ligand exchange and chelation; finally, during the sintering process, the metal-polymer composite precursor is transformed into a functional metal or metal oxide phase, thereby introducing and retaining the required functional components in situ and uniformly in the overall three-dimensional structure of the final metal part, rather than just staying on the surface.

[0023] (6) This invention completely replaces the traditional thermal decomposition pore-forming process with a mild solvent dissolution pore-forming process, eliminating the gas pressure source that causes defects in parts from the root. Solvent dissolution is a physical process based on the Flory-Huggins theory, which is thermodynamically spontaneous and does not produce gas, completely avoiding the bubbling and cracking caused by the high-pressure gas generated by thermal decomposition according to the ideal gas law. At the same time, the diffusion of solvent molecules follows Fick's law, and its dynamics can be precisely controlled by the Arrhenius relationship between temperature and time, thereby achieving the directionality and controllability of the pore formation process. This not only ensures the structural integrity of the green body, but also creates ideal conditions for the uniform penetration of the subsequent functional solution.

[0024] This solves the problems in existing technologies, such as low green strength, uncontrollable pore structure, difficulty in functional modification, incompatibility with traditional binder systems, and complex post-processing.

[0025] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0026] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein...

[0027] Figure 1 This is a schematic diagram illustrating the flowability of the coated powder provided according to an embodiment of this application.

[0028] Figure 2 This is a schematic diagram of the bending strength of the printed green blank provided according to an embodiment of this application.

[0029] Figure 3 This is a comparison diagram of the flexural strength and green strength of the enhanced porous green body provided according to the embodiments of this application.

[0030] Figure 4This is a scanning electron microscope image of the final metal part provided according to Embodiment 3 of this application. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] In the embodiments of this application, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0033] The present application will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0034] Example 1 This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportion of the organic coating layer includes: Rigid polymer backbone: 35 parts; Polymers containing coordinating groups: 10 parts; Soluble porogen: 10 parts; Lubricant: 5 parts; Leveling agent: 0.5 parts; Antioxidant: 0.5 parts; Defoaming agent: 0.5 parts; Antistatic agent: 0.5 parts.

[0035] The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0036] The rigid polymer backbone is selected from homopolymer polyacetal, and the coordinating group is selected from carboxyl groups.

[0037] The soluble porogen is polymethyl methacrylate microspheres with a particle size distribution D50 of 5-30 μm.

[0038] Among them, the lubricant is selected from paraffin wax; the antioxidant is selected from hindered phenolic antioxidants; the defoamer is selected from polysiloxane defoamers; the leveling agent is selected from acrylate leveling agents; and the antistatic agent is selected from ethoxylated fatty amine antistatic agents.

[0039] It should be noted that the acrylate leveling agent is BYK-354 or BYK-355, the polysiloxane defoamer is BYK-A530 or BYK-A535, and the ethoxylated fatty amine antistatic agent is Atmer163 or Atmer129.

[0040] The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 5:1.

[0041] This application also provides a method for preparing coated powder for ultra-high-speed laser metal 3D printing, including the following steps: S1. Add the rigid polymer backbone, polymer containing coordinating groups, soluble pore-forming agent, lubricant, leveling agent, antioxidant, defoamer and antistatic agent into a high-speed mixer according to the ratio, and mix at 1200 rpm for 8 minutes at room temperature to obtain organic binder premix; S2. Add the organic binder premix obtained in step S1 into a twin-screw extruder. The screw speed of the twin-screw extruder is 300 rpm. The extrusion temperature from the feeding section to the die head is 160-180℃, 180-200℃, 200-220℃, and 200-220℃ respectively. Melt blend at 160-220℃, extrude and granulate to obtain organic binder particles. S3. The organic binder particles obtained in step S2 are crushed in a low-temperature pulverizer, sieved, and organic binder powder with a particle size of 5-30μm is selected. S4. Add the metal powder and the organic binder powder obtained in step S3 into a three-dimensional mixer according to the ratio, and mix at 200 rpm for 60 minutes at room temperature to make the organic binder powder uniformly coat the surface of the metal powder, so as to obtain the coating powder for ultra-high speed laser metal 3D printing.

[0042] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide coating powder; S2. Using powder bed laser melting or laser powder bed sintering technology, 3D printing is performed with parameters of 1000W laser power, 3000mm / s scanning speed and 20μm layer thickness, and the layers are stacked one by one to form a printed blank with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 1.5 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing coordinating groups to obtain an enhanced porous green body. S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0043] In step S3, the cleaning solvent is acetone, the cleaning temperature is 40°C, and the cleaning time is 6 hours; in step S4, the multivalent metal ions are selected from Fe. 3+ Al 3+ Cu 2+ Zn 2+ Ca 2+ At least one of the following, the soaking time is 2-48 hours.

[0044] In step S5, the catalytic degreasing temperature is 150℃ and the holding time is 6 hours; the vacuum sintering temperature is 1100℃ and the holding time is 2 hours.

[0045] Example 2 This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportion of the organic coating layer includes: Rigid polymer backbone: 42 parts; Polymers containing coordinating groups: 15 parts; Soluble porogen: 15 parts; Lubricant: 7 parts; Leveling agent: 0.8 parts; Antioxidant: 1 part; Defoaming agent: 0.8 parts; Antistatic agent: 0.8 parts.

[0046] The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0047] The rigid polymer backbone is selected from copolymer polyacetal, and the coordinating group is selected from pyridyl.

[0048] The soluble porogen is polystyrene microspheres with a particle size distribution D50 of 5-30 μm.

[0049] Among them, the lubricant is selected from polyethylene wax; the antioxidant is selected from phosphite antioxidants; the defoamer is selected from non-silicone defoamers; the leveling agent is selected from organosilicon leveling agents; and the antistatic agent is selected from glyceryl monostearate antistatic agents.

[0050] It should be noted that the silicone leveling agent is BYK-310 or BYK-333, the non-silicone defoamer is BYK-051 or BYK-052, and the glyceryl monostearate antistatic agent is Atmer122 or Atmer125.

[0051] The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 4:1.

[0052] The preparation method of a coating powder for ultra-high-speed laser metal 3D printing is the same as that in Example 1.

[0053] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide coating powder; S2. Using powder bed laser melting or laser powder bed sintering technology, 3D printing is performed with parameters of 1000W laser power, 3000mm / s scanning speed and 20μm layer thickness, and the layers are stacked one by one to form a printed blank with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing coordinating groups to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0054] In step S3, the cleaning solvent is selected from ethanol, the cleaning temperature is 60℃, and the cleaning time is 12 hours; in step S4, the multivalent metal ions are selected from Al. 3+ The soaking time is 24 hours.

[0055] In step S5, the catalytic degreasing temperature is 90℃ and the holding time is 2 hours; the vacuum sintering temperature is 1200℃ and the holding time is 2 hours.

[0056] Example 3 This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportion of the organic coating layer includes: Rigid polymer skeleton: 50 parts; Polymers containing coordinating groups: 20 parts; Soluble porogen: 20 parts; Lubricant: 10 parts; Leveling agent: 1.2 parts; Antioxidant: 1.7 parts; Defoaming agent: 1.2 parts; Antistatic agent: 1.2 parts.

[0057] The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0058] The rigid polymer backbone is selected from homopolymer polyacetal, and the coordinating group is selected from amino groups.

[0059] The soluble porogen is polyacrylate microspheres with a particle size distribution D50 of 5-30 μm.

[0060] Among them, the lubricant is selected from stearic acid; the antioxidant is selected from hindered phenolic antioxidants; the defoamer is selected from polysiloxane defoamers; the leveling agent is selected from organosilicon leveling agents; and the antistatic agent is selected from glyceryl monostearate antistatic agents.

[0061] It should be noted that the silicone leveling agent is BYK-310 or BYK-333, the polysiloxane defoamer is BYK-A530 or BYK-A535, and the glyceryl monostearate antistatic agent is Atmer122 or Atmer125.

[0062] The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 3:1.

[0063] The preparation method of a coating powder for ultra-high-speed laser metal 3D printing is the same as that in Example 1.

[0064] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide coating powder; S2. Using powder bed laser melting or laser powder bed sintering technology, 3D printing is performed with parameters of 1000W laser power, 3000mm / s scanning speed and 20μm layer thickness, and the layers are stacked one by one to form a printed blank with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing coordinating groups to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0065] In step S3, the cleaning solvent is water, the cleaning temperature is 60℃, and the cleaning time is 24 hours; in step S4, the multivalent metal ions are selected from Ca.2+ The soaking time is 48 hours.

[0066] In step S5, the catalytic degreasing temperature is 150℃ and the holding time is 6 hours; the vacuum sintering temperature is 1300℃ and the holding time is 3 hours.

[0067] Example 4 This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportion of the organic coating layer includes: Rigid polymer backbone: 62 parts; Polymers containing coordinating groups: 25 parts; Soluble porogen: 25 parts; Lubricant: 12 parts; Leveling agent: 1.5 parts; Antioxidant: 2.2 parts; Defoaming agent: 1.5 parts; Antistatic agent: 1.5 parts.

[0068] The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0069] The rigid polymer backbone is selected from homopolymer polyacetal, and the coordinating group is selected from carboxyl groups.

[0070] The soluble porogen is polymethyl methacrylate microspheres with a particle size distribution D50 of 5-30 μm.

[0071] The lubricant is selected from paraffin wax, polyethylene wax and stearic acid; the antioxidant is selected from phosphite antioxidants; the defoamer is selected from polysiloxane defoamers and non-silicone defoamers; the leveling agent is selected from acrylate leveling agents; and the antistatic agent is selected from ethoxylated fatty amine antistatic agents.

[0072] It should be noted that the acrylate leveling agent is BYK-354 or BYK-355, the polysiloxane defoamer is BYK-A530 or BYK-A535, the non-silicone defoamer is BYK-051 or BYK-052, and the ethoxylated fatty amine antistatic agent is Atmer163 or Atmer129.

[0073] The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 2:1.

[0074] The preparation method of a coating powder for ultra-high-speed laser metal 3D printing is the same as that in Example 1.

[0075] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide coating powder; S2. Using powder bed laser melting or laser powder bed sintering technology, 3D printing is performed with parameters of 1000W laser power, 3000mm / s scanning speed and 20μm layer thickness, and the layers are stacked one by one to form a printed blank with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing coordinating groups to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0076] In step S3, the cleaning solvent is acetone, the cleaning temperature is 40°C, and the cleaning time is 8 hours; in step S4, the polyvalent metal ions are selected from Zn. 2+ The soaking time is 48 hours.

[0077] In step S5, the catalytic degreasing temperature is 150℃ and the holding time is 6 hours; the vacuum sintering temperature is 1400℃ and the holding time is 4 hours.

[0078] Example 5 This application provides a coating powder for ultra-high-speed laser metal 3D printing. The coating powder consists of metal powder and an organic coating layer covering the surface of the metal powder. The weight proportion of the organic coating layer includes: Rigid polymer skeleton: 70 parts; Polymers containing coordinating groups: 30 parts; Soluble porogen: 30 parts; Lubricant: 15 parts; Leveling agent: 2 parts; Antioxidant: 3 parts; Defoaming agent: 2 parts; Antistatic agent: 2 parts.

[0079] The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

[0080] The rigid polymer backbone is selected from the copolymer polyacetal, and the coordinating group is selected from amino groups.

[0081] The soluble porogen is polyacrylate microspheres with a particle size distribution D50 of 5-30 μm.

[0082] Among them, the lubricant is selected from paraffin wax; the antioxidant is selected from phosphite antioxidants; the defoamer is selected from polysiloxane defoamers; the leveling agent is selected from acrylate leveling agents; and the antistatic agent is selected from ethoxylated fatty amine antistatic agents.

[0083] It should be noted that the acrylate leveling agent is BYK-354 or BYK-355, the polysiloxane defoamer is BYK-A530 or BYK-A535, and the ethoxylated fatty amine antistatic agent is Atmer163 or Atmer129.

[0084] The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 1:1.

[0085] The preparation method of a coating powder for ultra-high-speed laser metal 3D printing is the same as that in Example 1.

[0086] This application also provides an ultra-high-speed laser metal 3D printing method, including the following steps: S1. Provide coating powder; S2. Using powder bed laser melting or laser powder bed sintering technology, 3D printing is performed with parameters of 1000W laser power, 3000mm / s scanning speed and 20μm layer thickness, and the layers are stacked one by one to form a printed blank with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing coordinating groups to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

[0087] In step S3, the cleaning solvent is selected from ethanol, the cleaning temperature is 60℃, and the cleaning time is 24 hours; in step S4, the multivalent metal ions are selected from Al. 3+ Cu 2+ The soaking time is 48 hours.

[0088] In step S5, the catalytic degreasing temperature is 150℃ and the holding time is 6 hours; the vacuum sintering temperature is 1400℃ and the holding time is 4 hours.

[0089] Comparative Example 1 The difference from Example 1 is that the amount of polymer containing coordinating groups is increased to the rigid polymer backbone, while the remaining proportions and preparation process are the same as in Example 1.

[0090] Comparative Example 2 The difference from Example 1 is that no soluble porogen is added, the reduced amount is increased to the rigid polymer backbone, and the remaining proportions and preparation process are the same as in Example 1.

[0091] Comparative Example 3 Using conventional SLM technology, uncoated titanium alloy powder (Ti-6Al-4V, particle size 15-53μm) is directly printed under the same laser parameters without subsequent solvent pore-forming and ion crosslinking treatments.

[0092] Performance testing and characterization The flowability of the coated powder was tested using a Hall effect flowmeter (according to GB / T1482-2010 standard), and the results are as follows: Figure 1 As shown, the flowability of the coated powders prepared in Examples 1-5 of this invention is 17.8-19.5 s / 50g, which is lower than that of the uncoated metal powder (Comparative Example 3, 11.5 s / 50g). This is an inevitable result of the increased surface roughness and adhesion of the particles after the introduction of the organic coating layer, which is in line with the basic principles of powder metallurgy. Among them, Example 3 has the best flowability because although it contains high levels of coordinating polymers and pore-forming agents, it also has the highest lubricant content. The surface lubrication effect of the lubricant partially offsets the thickening effect of the coating layer. Example 5 has the worst flowability because it has the highest total content of organic coating layer and a relatively low proportion of lubricant.

[0093] Comparative Example 1, lacking a polymer containing coordinating groups but with an increased rigid polymer skeleton, suffered further deterioration in flowability. Comparative Example 2, lacking a soluble pore-forming agent, lacked the ball bearing effect of microspheres, resulting in inferior flowability compared to the example group. Comparative Example 3, being uncoated bare powder, demonstrated the advantages of conventional metal powder spreading in terms of excellent flowability, but its green strength was extremely low, unable to support complex structures, a stark contrast to the present invention.

[0094] The bending strength of the printed green body was tested using the three-point bending method, and the results are as follows: Figure 2 As shown, the green body flexural strength of Examples 1-5 of the present invention reached 4.8-6.5 MPa, which is 3-5 times higher than that of Comparative Example 1 (polymer without coordinating groups) (1.2 MPa) and 1.7-2.3 times higher than that of Comparative Example 2 (polymer without porogen) (2.8 MPa). Example 3 showed the highest strength (6.5 MPa), verifying the carboxyl-Fe 3+ Strong coordination interactions. Comparative Example 3, lacking an organic coating layer, had almost no strength in its green body and could not be molded into complex structures.

[0095] A comprehensive analysis of the flowability and flexural strength data of Examples 1-5 and Comparative Examples 1-3 revealed a significant correlation between flowability and flexural strength. Lower flowability values ​​correlated with higher flexural strength. Flowability was concentrated in the range of 17.8–19.5 s / 50g, while flexural strength remained stable between 4.8 and 6.5 MPa. Example 3, with its optimal flowability and highest flexural strength, represented the best solution balancing both properties. The comparative examples, on the other hand, demonstrated the necessity of the coating layer and key components: Comparative Example 1 lacked a coordinating polymer, and Comparative Example 2 lacked a soluble porogen, both resulting in poor flowability (20.3 and 19.8 s / 50g) and a sharp drop in flexural strength (1.2 and 2.8 MPa). Comparative Example 3, consisting of uncoated powder, exhibited the best flowability (11.5 s / 50g), but due to the lack of a coating layer for adhesion, it could not be molded, resulting in zero strength. Further analysis shows that the binding effect of carboxyl coordination groups is better than that of pyridyl and amino groups. Lubricants can effectively improve fluidity without sacrificing strength. The total content of the coating layer needs to be matched with the lubricant to find a performance balance point, and should not be blindly increased.

[0096] In summary, this invention, through the rational design of the coating layer formulation, sacrifices approximately 55% of the flowability within a controllable range, enabling the originally unformable bare powder to obtain an excellent flexural strength of 6.5 MPa. The coordination polymer and soluble pore-forming agent are the core components that ensure both strength and flowability. The formulation in Example 3 is the optimal practical solution.

[0097] The porosity of the obtained porous green body was tested using the mercury intrusion porosimetry method, and the results are shown in Table 1 below.

[0098] Table 1. Porosity test results of porous green bodies

[0099] As shown in Table 1, the porous green bodies prepared in Examples 1-5 of the present invention have excellent porosity characteristics. The porosity can be precisely controlled within the range of 31.8%-45.8%, and the average pore diameter can be adjusted as needed within the range of 4.2-22.5μm, which fully demonstrates the effectiveness and flexibility of the programmable pore-forming technology of the present invention.

[0100] Firstly, regarding porosity control, Example 3 exhibits the highest porosity, which closely matches its formulation design, which maximizes the content of soluble porogen and minimizes the particle size of the porogen. Example 1 shows the lowest porosity due to its relatively low porogen content. The porosity of Examples 2-5 exhibits a regular variation with porogen content and particle size, demonstrating that the present invention can precisely control porosity by adjusting the porogen content.

[0101] Secondly, regarding pore size control, Example 3 has the smallest average pore size, corresponding to the smallest pore size of its pore-forming agent; Example 4 has the largest average pore size, corresponding to the largest pore size of its pore-forming agent. Therefore, the cavity size left after the pore-forming agent dissolves is highly correlated with the original particle size of the pore-forming agent, proving the scientific validity of the template sacrificial pore-forming mechanism of the present invention.

[0102] Compared with the comparative examples, the porosity and pore size of Comparative Example 1 are similar to those of Example 1, indicating that the polymer containing coordinating groups has no significant effect on the pore-forming process; while the porosity of Comparative Example 2 is only 5.8%, which is much lower than that of the Example group, and it cannot form interconnected channels (the average pore size cannot be measured), proving that the soluble porogen is a necessary component for forming the porous structure of the present invention.

[0103] The flexural strength of the reinforced porous green body was tested and compared with the green body strength. The results are as follows: Figure 3 As shown, the green strength of Examples 1-5 was further increased by 1.66-1.82 times after ionic crosslinking, with Example 3 reaching a strength of 11.8 MPa. Comparative Example 1, lacking coordinating groups, showed only a limited strength increase (1.25 times). This verifies the strengthening mechanism of the coordination crosslinking network formed by polymers containing coordinating groups and polyvalent metal ions.

[0104] SEM observation of the final metal parts, such as Figure 4 As shown in Example 3, its surface has uniformly distributed micron-sized pores with dense pore wall structure and clear outline, without obvious collapse or adhesion. This indicates that during the sintering process, the organic coating layer was effectively removed after ion crosslinking and heat treatment, while retaining good skeleton stability. The pores are approximately spherical or ellipsoidal, uniformly distributed, without obvious agglomeration or local dense areas, indicating that a stable three-dimensional porous network has been formed in the green stage and maintained in subsequent sintering.

[0105] The compressive properties of the final metal parts were tested using a universal testing machine, and the results are shown in Table 2 below.

[0106] Table 2 Compressive properties of metal parts

[0107] As shown in Table 2, the porous metal parts prepared in Examples 1-5 of this invention exhibit a significant and regular correlation between their compressive properties and porosity, and show obvious differences compared to the comparative examples, strongly demonstrating the core technological advantages of "programmable porosity and adjustable mechanical properties". Regarding the compressive modulus, Examples 1-5 range from 1.8 to 2.8 GPa, showing an overall negative correlation with porosity: Example 1 (32.5%), with the lowest porosity, has the highest modulus (2.8 GPa), while Example 3 (42.3%), with the highest porosity, has the lowest modulus (1.8 GPa). The decrease in modulus and the increase in porosity conform to the theoretical relationship between the elastic modulus and porosity of porous materials, indicating that the stiffness of the component can be precisely controlled by adjusting the content of the pore-forming agent. Regarding compressive strength, Examples 1-5 ranged from 62-85 MPa, decreasing with increasing porosity. Example 1 exhibited the highest strength, while Example 3 showed the lowest, with a difference of approximately 27%. Even with a porosity as high as 42.3%, Example 3's strength of 62 MPa was still significantly higher than that of human cancellous bone, and its modulus of 1.8 GPa matched that of human bone, effectively preventing stress shielding and fully meeting the requirements for bone implants. Comparative Example 1, lacking a coordinating polymer, maintained a porous structure, but after sintering, excessive grain growth resulted in reduced submicron-level pores and a significant decrease in specific surface area. Comparative Examples 2 and 3, being dense metals, had modulus and strength far exceeding those of the Examples, but lacked a porous structure, thus lacking the conditions for material transport and bone ingrowth, making them unsuitable for implant-related applications.

[0108] In summary, this invention, through the design of an organic coating system containing a coordinating polymer, a soluble porogen, and a lubricant working synergistically, significantly improves the flexural strength of the printed green body while appropriately reducing powder flowability within a controllable range, achieving an optimal balance between flowability and green body strength. The porosity and average pore size of the prepared porous green body can be precisely controlled by adjusting the porogen content and particle size, exhibiting programmable pore creation characteristics. After ionic crosslinking, the green body strength is further significantly improved. The compressive modulus and strength of the sintered porous metal parts are regularly adjustable with porosity, and their mechanical properties are highly compatible with human bones, meeting structural support requirements while avoiding stress shielding effects. The comparative results fully verify that the coordinating polymer and the soluble porogen are key components for achieving high-strength green bodies, interconnected porous structures, and adjustable mechanical properties. Samples without bare powder or lacking key components cannot simultaneously achieve formability, porous structures, and suitable mechanical properties. Therefore, the technical route of this invention is reasonable and the formulation system is perfect. It can prepare metal components that have good printability, uniform and controllable porous structure and ideal mechanical properties. It is especially suitable for applications such as bone implants that have synergistic requirements for porosity and mechanical properties.

[0109] According to the embodiments of this application, a coating powder, preparation method, and printing method for ultra-high-speed laser metal 3D printing are proposed. By co-coating a polymer containing coordinating groups and a soluble pore-forming agent onto the surface of metal powder, a composite coating layer with both reaction sites and sacrificial template functions is constructed, innovatively achieving controllable preparation and performance optimization of porous metal components. The coordinating polymer can form a cross-linked network with multivalent metal ions, significantly improving the green strength; the pore-forming agent is removed by mild solvent dissolution, forming interconnected channels without gas generation, avoiding cracking defects, and allowing for precise control of porosity and pore size. The capillary network formed by the channels facilitates uniform ion penetration and diffusion, forming a gradient-reinforced structure in situ with the coordinating groups, and the cross-linking density can be precisely controlled by ion concentration and soaking time. The final component has both micron-level main channels and submicron-level network pores, synergistically improving mass transfer efficiency and specific surface area; combined with catalytic debinding and vacuum sintering, the decoupled control of green strength and sintering densification is achieved. At the same time, the coordinating groups transform the binder from a traditional sacrificial phase into a functional precursor, realizing the in-situ uniform introduction of functional components into the three-dimensional structure. This technology eliminates thermal decomposition defects at the source and solves existing technical problems such as low green strength, uncontrollable porosity, difficulty in functionalization, and complex processes.

[0110] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

[0111] The present application and its embodiments have been described above. This description is not restrictive, and the actual application is not limited thereto. In conclusion, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of this application, such design should fall within the protection scope of this application.

Claims

1. A coating powder for ultra-high-speed laser metal 3D printing, characterized in that, The coated powder comprises metal powder and an organic coating layer covering the surface of the metal powder, wherein the weight proportion of the organic coating layer includes: Rigid polymer skeleton: 35-70 parts; Polymers containing coordinating groups: 10-30 parts; Soluble porogen: 10-30 parts; Lubricant: 5-15 parts; Leveling agent: 0.5-2 parts; Antioxidant: 0.5-3 parts; Defoaming agent: 0.5-2 parts; Antistatic agent: 0.5-2 parts.

2. The coating powder for ultra-high-speed laser metal 3D printing according to claim 1, characterized in that, The metal powder is selected from at least one of titanium alloy, stainless steel, cobalt-chromium alloy, aluminum alloy, and copper alloy, and its particle size distribution is 15-53 μm.

3. The coating powder for ultra-high-speed laser metal 3D printing according to claim 1, characterized in that, The rigid polymer backbone is selected from at least one of homopolymer polyacetal and copolymer polyacetal, and the coordinating group is selected from at least one of carboxyl, amino, and pyridyl groups.

4. The coating powder for ultra-high-speed laser metal 3D printing according to claim 1, characterized in that, The soluble porogen is polymethyl methacrylate microspheres, polystyrene microspheres, or polyacrylate microspheres, with a particle size distribution D50 of 5-30 μm.

5. The coating powder for ultra-high-speed laser metal 3D printing according to claim 1, characterized in that, The lubricant is selected from at least one of paraffin wax, polyethylene wax, and stearic acid; the antioxidant is selected from at least one of hindered phenolic antioxidants and phosphite antioxidants; the defoamer is selected from at least one of polysiloxane defoamers and non-silicone defoamers; the leveling agent is selected from at least one of acrylate leveling agents and organosilicon leveling agents; and the antistatic agent is selected from at least one of ethoxylated fatty amine antistatic agents and glyceryl monostearate antistatic agents.

6. The coating powder for ultra-high-speed laser metal 3D printing according to claim 1, characterized in that, The mass ratio of the rigid polymer backbone to the polymer containing coordinating groups is 5:1 to 1:

1.

7. A method for preparing the coating powder for ultra-high-speed laser metal 3D printing as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Add the rigid polymer backbone, polymer containing coordinating groups, soluble pore-forming agent, lubricant, leveling agent, antioxidant, defoamer and antistatic agent into a high-speed mixer according to the ratio, and mix at 500-1500 rpm for 5-15 minutes at room temperature to obtain organic binder premix; S2. Add the organic binder premix obtained in step S1 into a twin-screw extruder. The screw speed of the twin-screw extruder is 100-300 rpm, and the extrusion temperature from the feeding section to the die head is 160-180℃, 180-200℃, 200-220℃, and 200-220℃ respectively. Melt blend at 160-220℃, extrude and granulate to obtain organic binder particles. S3. The organic binder particles obtained in step S2 are crushed in a low-temperature pulverizer, sieved, and organic binder powder with a particle size of 5-30μm is selected. S4. Add the metal powder and the organic binder powder obtained in step S3 into a three-dimensional mixer according to the ratio, and mix at 50-200 rpm for 30-90 minutes at room temperature to make the organic binder powder uniformly coat the surface of the metal powder, so as to obtain the coating powder for ultra-high speed laser metal 3D printing.

8. A method for ultra-high-speed laser metal 3D printing as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Providing the coating powder as described in any one of claims 1-6; S2. Using powder bed laser melting or laser powder bed sintering processes, 3D printing is performed with parameters of laser power 200-1000W, scanning speed 500-3000mm / s, and layer thickness 20-60μm, layer by layer to form a printed green body with a preset three-dimensional shape. S3. Immerse the printed green body obtained in step S2 in a cleaning solvent to dissolve and remove the soluble pore-forming agent, forming a connected micron-scale pore network inside the green body to obtain a porous green body; S4. Immerse the porous green body obtained in step S3 into a polyvalent metal ion solution with a concentration of 0.1-2.0 mol / L, so that the metal ions diffuse into the interior of the green body and form a coordination crosslinking network with the polymer containing the coordinating group to obtain an enhanced porous green body; S5. The reinforced porous green blank obtained in step S4 is subjected to catalytic degreasing and vacuum sintering treatment in sequence to finally obtain a metal part with a multi-level porous structure.

9. The ultra-high-speed laser metal 3D printing method according to claim 8, characterized in that, In step S3, the cleaning solvent is selected from at least one of water, ethanol, and acetone; the cleaning temperature is 20-60℃; and the cleaning time is 1-24 hours. In step S4, the multivalent metal ion is selected from Fe. 3+ Al 3+ Cu 2+ Zn 2+ Ca 2+ At least one of the following, the soaking time is 2-48 hours.

10. The ultra-high-speed laser metal 3D printing method according to claim 8, characterized in that, In step S5, the catalytic degreasing temperature is 80-150℃, and the holding time is 2-6 hours; the vacuum sintering temperature is 1100-1400℃, and the holding time is 2-4 hours.

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