Medical 3D printing zinc-based spherical powder for orthopedics department and preparation method

Abstract

The invention provides medical 3D printing zinc-based spherical powder for the orthopedics department and a preparation method, and belongs to the technical field of metal powder materials and preparation. The zinc-based metal melt is drained to the center of a disc rotating at a high speed, after rotation acceleration, splitting, balling, cooling and solidification are conducted, and zinc-based spherical powder is obtained; and the zinc-based spherical powder is screened, and the zinc-based spherical powder is obtained. The high-quality medical 3D printing zinc-based spherical powder for the orthopedics department is prepared by selecting zinc-based metal and combining with the improved rotating disc, the hollow powder rate of the prepared 3D printing zinc-based spherical powder is reduced to be within 1%, the sphericity degree of the powder is high, the difference between D90 and D10 of the particle size of the powder is smaller than 10 m, and the powder utilization rate can reach 90% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder materials and preparation technologies, and in particular, to an orthopedic medical 3D printing zinc-based spherical powder and a preparation method thereof. Background Art

[0002] Due to the differences in human bone structures and diseases, conventional orthopedic diagnosis and treatment methods such as "cutting the feet to fit the shoes" have problems such as poor surgical accuracy, the need to improve the matching of implant devices, and large surgical traumas, resulting in relatively high surgical risks. "Digital precision diagnosis and treatment" has become the main trend in the development of orthopedic medicine at home and abroad. As a key technology leading a new round of scientific and technological and industrial revolutions, 3D printing can achieve the digital precision customization of orthopedic medical devices, providing an excellent technical approach for the digital precision diagnosis and treatment of orthopedic medicine.

[0003] However, at present, there is still a problem of insufficient high-quality medical powder raw materials in the 3D printing technology of orthopedic medicine in China. High-quality medical raw material powders rely on imports. To solve the above problems, in the prior art, the Chinese invention patent with the publication number of CN118218580A discloses a spherical zinc-based metal powder material, a preparation method and an application thereof. By adopting a rotating disk centrifugal atomization process, the problems of low sphericity of zinc-based metal powder and the generation of hollow powder caused by vacuum atomization are solved, and high-quality spherical zinc-based metal powder materials are prepared. However, this technical solution still has corresponding technical problems, that is, this solution only reduces the generation probability of hollow powder, and the reduction degree is limited. The concentration of the powder particle size distribution is relatively low, the proportion of non-spherical powder is still large, and the unusable powder rate obtained by screening is relatively high. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides an orthopedic medical 3D printing zinc-based spherical powder and a preparation method thereof. By selecting a zinc-based metal and combining an improved rotating disk, high-quality orthopedic medical 3D printing zinc-based spherical powder is prepared. The hollow powder rate of the prepared 3D printing zinc-based spherical powder is reduced to less than 1%, the powder has high sphericity, the difference between D90 and D10 of the powder particle size is less than 10 µm, and the powder utilization rate can reach more than 90%.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a method for preparing orthopedic medical 3D printing zinc-based spherical powder, comprising: preparing a zinc-based metal melt meeting the composition requirements; draining the zinc-based metal melt to the center of a high-speed rotating disk, and after rotation acceleration, splitting, forming spheres, cooling, and solidifying to obtain zinc-based spherical powder material; screening the zinc-based spherical powder material to obtain the zinc-based spherical powder; in the zinc-based metal, by mass percentage, Cu: 0.1% - 7.0%, Mg: 0.02% - 0.10%, Al: 3.5% - 4.5%, Li ≤ 0.01%, Mn ≤ 0.02%, and the rest is Zn; the disk has an impact zone, an advection zone, and a secondary atomization zone; the impact zone is located in the middle of the disk for receiving the zinc-based metal melt, and the impact zone has a drainage structure; the advection zone is annular and is located on the side of the disk away from the disk center; the secondary atomization zone is annular and is located on the side away from the disk center relative to the advection zone.

[0006] Further, the temperature of the zinc-based metal melt is Tm + 10°C - Tm + 50°C, where Tm is the liquidus temperature of the zinc-based metal melt.

[0007] Further, the free vertical falling distance of the zinc-based metal melt is 30 cm - 50 cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min - 5.0 kg / min.

[0008] Further, the rotation speed of the disk is 20000 rpm - 60000 rpm.

[0009] Further, the drainage structure is a hemispherical protrusion provided in the impact zone, the diameter of the hemispherical protrusion is 0.5 mm - 2.5 mm, and as it is farther away from the disk center, the diameter of the hemispherical protrusion gradually increases.

[0010] Further, the impact zone and the advection zone are heated, and the heating temperature is Tm + 5°C - Tm + 10°C, where Tm is the liquidus temperature of the zinc-based metal melt.

[0011] Further, the secondary atomization zone is connected to the advection zone through a connecting part, and the circumferential sectional area of the connecting part accounts for no more than 1 / 10 of the circumferential area.

[0012] Further, the minimum distance between the secondary atomization zone and the rotation axis forms a first distance, the maximum distance between the advection zone of the disk and the rotation axis forms a second distance, and the difference between the first distance and the second distance is related to the second distance and the rotation speed of the disk; The difference ΔL between the first distance and the second distance satisfies the following formula:

[0013] Wherein, L2 is the second distance, and L0 is the standard distance. is the correction coefficient, with the unit of mm, v is the rotation speed of the disk, and v0 is the standard speed.

[0014] Further, the symmetry axis of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis and is parallel to the surface of the advection zone. The symmetry axis is located above the surface of the advection zone, and there is a gap between them, and the size of the gap is 0.01 mm - 0.05 mm; the secondary atomization zone includes a flow-facing part and a flow-guiding part. The surface of the radial cross-section of the flow-facing part is the first arc, and the center of curvature of the first arc is arranged away from the disk center relative to the first arc and the radius of curvature is 0.1 mm - 0.5 mm; the flow-guiding part includes an upper flow-guiding part and a lower flow-guiding part. The surfaces of the radial cross-sections of the upper flow-guiding part and the lower flow-guiding part are the second arcs. The center of curvature of the second arc is arranged close to the disk center relative to the second arc, and the range of the radius of curvature of the second arc is 5 mm - 10 mm; the angle between the tangent line of the intersection point of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disk and passing through the intersection point is 100° - 130°.

[0015] The present invention also provides an orthopedic medical 3D printing zinc-based spherical powder, which is prepared by the above preparation method.

[0016] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: The zinc-based metal proposed by the present invention limits its composition. Zinc is an essential trace element for the human body, participates in protein synthesis, enzyme reactions, and bone metabolism regulation, has low toxicity and a clear metabolic pathway, and the degradation products (such as )(It) can induce calcium and phosphorus deposition, promote bone integration, and its degradation rate is between that of magnesium-based (too fast) and iron-based (too slow). Zinc has insufficient mechanical strength (such as low tensile strength), and its performance can be significantly improved through alloying (adding elements such as Cu, Ag, Li, etc.). Among them, Cu can also increase the antibacterial property of the prepared product, and adding elements such as Li, Mn, Mg, and Al can refine the grain structure. Secondly, the preparation process of spherical powder is highly related to the properties of the material. For example, for zinc-based metal powder, in the zinc-based metal in this application, the Zn content is as high as at least 85%. The viscosity and surface free energy of the zinc melt are relatively low, so it is easy to produce hollow powder during the preparation process. This is related to the properties of the material itself. Therefore, a suitable preparation process needs to be selected for the zinc-based metal material proposed in this application to prepare high-quality orthopedic medical 3D printing zinc-based spherical powder. Thirdly, in order to solve the problems in the preparation process of zinc-based spherical powder in the prior art, the specific structure of the disc is defined. The specific structure of the disc combined with the preparation process is the key to preparing high-quality zinc-based spherical powder. For example, the impact zone has a flow splitting structure, and the flow splitting structure is designed to split the diverted metal melt so that its circumferential flow rates are approximately the same, thereby forming a zinc-based metal melt layer with the same thickness and flow rate in the same radius area of the laminar flow zone. This step plays a decisive role in preparing spherical powder with a concentrated particle size distribution. In the rotating disk atomization powder preparation process, if the radial flow rate difference is large, it will lead to a large difference in the particle size distribution of the prepared powder. For example, the thicker zinc-based metal melt is subjected to a larger centrifugal force and passes through the edge of the disk faster, tearing into larger-sized small droplets, while the thinner zinc-based metal melt passes through the edge of the disk and tears into smaller-sized droplets, resulting in a poor particle size distribution. On the other hand, for the zinc-based metal melt, after it detaches from the disk, it is cooled by inert gas. The larger the droplet size, the easier it is to form hollow powder. This is also the reason why hollow powder is prone to appear in zinc-based metal powder in the prior art. Therefore, this is also the reason for setting up the secondary atomization zone in this application. The secondary atomization zone performs secondary atomization on larger-sized droplets. At the same time, the secondary atomization zone is not heated. After the droplets impact in the secondary atomization zone, the droplet speed is reduced and they split into smaller-sized droplets. Combined with cooling, it avoids the formation of hollow powder due to the impact of the cooling gas on the droplets. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Schematic diagram of the disc structure provided by the embodiment of the present invention; Figure 2 isFigure 1 Partial enlarged view at position A in Figure 3 Disc cross-sectional view provided by the embodiment of the present invention; Figure 4 is Figure 3 Partial enlarged view at position C in Figure 5 SEM image of peanut-shaped powder in the prior art; Figure 6 SEM image of the powder of the zinc-based composite powder material prepared in Example 1 of the present invention, a is the overall morphology diagram, and b is the partial enlarged view Figure 7 SEM image of the powder of the zinc-based composite powder material prepared in Comparative Example 1 of the present invention, a is the first position, and b is the second position.

[0019] Reference numerals: 01, impact zone; 010, drainage structure; 02, advection zone; 03, secondary atomization zone; 030, upstream portion; 031, diversion portion; 04, connection portion. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The specific implementation manners of the present invention are not limited to the specific embodiments given here. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the disclosed specific embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific implementation manners and do not limit the present invention.

[0022] The present invention provides a method for preparing orthopedic medical 3D printing zinc-based spherical powder, including: S1. Prepare a zinc-based metal melt that meets the composition requirements.

[0023] In the zinc-based metal, by mass percentage, Cu: 0.1% - 7.0%, Mg: 0.02% - 0.10%, Al: 3.5% - 4.5%, Li ≤ 0.01%, Mn ≤ 0.02%, and the rest is Zn.

[0024] S2. Drain the zinc-based metal melt to the center of a high-speed rotating disc. After rotation acceleration, it splits, forms spheres, cools, and solidifies to obtain zinc-based spherical powder material.

[0025] Such as Figure 1As shown, the disk has an impact zone 01, a laminar flow zone 02, and a secondary atomization zone 03; the impact zone 01 is located in the middle of the disk and is used to receive the zinc-based metal melt, and the impact zone 01 has a flow splitting structure; the laminar flow zone 02 is annular and is located on the side of the disk away from the center of the disk; the secondary atomization zone 03 is annular and is located on the side away from the center of the disk relative to the laminar flow zone.

[0026] S3. Screen the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0027] The composition of the zinc-based metal proposed in the present invention is limited. Zinc is an essential trace element for the human body, participating in protein synthesis, enzyme reactions, and bone metabolism regulation, with low toxicity and a clear metabolic pathway. Degradation products (such as )(It) can induce calcium and phosphorus deposition, promote bone integration, and its degradation rate is between that of magnesium-based (too fast) and iron-based (too slow). Zinc has insufficient mechanical strength (such as low tensile strength), and its performance can be significantly improved through alloying (adding elements such as Cu, Ag, Li, etc.). Among them, Cu can also increase the antibacterial property of the prepared product, and adding elements such as Li, Mn, Mg, and Al can refine the grain structure. Secondly, the preparation process of spherical powder is highly related to the properties of the material. For example, for zinc-based metal powder, such as the zinc-based metal in this application, the Zn content is as high as at least 85%. The viscosity and surface free energy of the zinc melt are relatively low, so it is easy to produce hollow powder during the preparation process, which is related to the properties of the material itself. Therefore, a suitable preparation process needs to be selected for the zinc-based metal material proposed in this application to prepare high-quality orthopedic medical 3D printing zinc-based spherical powder. Thirdly, to solve the problems in the preparation process of zinc-based spherical powder in the prior art, the specific structure of the disk is limited. The specific structure of the disk combined with the preparation process is the key to preparing high-quality zinc-based spherical powder. For example, the impact area has a flow splitting structure, which is designed to split the metal melt flowing in, so that its circumferential flow rate is approximately the same, thereby forming a zinc-based metal melt layer with the same thickness and flow rate in the same radius area of the laminar flow area. This step plays a decisive role in preparing spherical powder with a concentrated particle size distribution. In the rotating disk atomization powder preparation process, if the radial flow rate difference is large, it will lead to a large difference in the particle size distribution of the prepared powder. For example, the zinc-based metal melt with a thicker thickness is also subject to a larger centrifugal force, and it passes through the edge of the disk faster, tearing into smaller droplets with a larger particle size, while the zinc-based metal melt with a thinner thickness passes through the edge of the disk and tears into smaller droplets, resulting in a poor particle size distribution. On the other hand, for the zinc-based metal melt, after it detaches from the disk, it is cooled by inert gas. The larger the droplet size, the easier it is to form hollow powder. This is also the reason why hollow powder is prone to appear in zinc-based metal powder in the prior art. Therefore, this is also the reason for setting up the secondary atomization area in this application. The secondary atomization area performs secondary atomization on larger droplets, and at the same time, the secondary atomization area is not heated. After the droplets impact in the secondary atomization area, the droplet speed is reduced and split into smaller droplets, combined with cooling, to avoid the droplets being impacted by the cooling gas to form hollow powder.

[0028] In the embodiment of the present invention, when preparing the zinc-based metal melt required for the composite composition, it is preferably to add materials by adding master alloy to reduce the burning loss of elements.

[0029] The temperature of the zinc-based metal melt is Tm + 10°C - Tm + 50°C, where Tm is the liquidus temperature of the zinc-based metal melt. By limiting the temperature of the zinc-based metal melt, the viscosity of the zinc-based melt meets specific requirements.

[0030] Specifically, the free vertical falling distance of the zinc-based metal melt is 30 cm - 50 cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min - 5.0 kg / min. Since a drainage structure is adopted in the technical solution of the present invention, it has a certain impact on the flow of the zinc-based metal melt. If the distance between the outlet of the zinc-based metal melt and the disc is set too small, the hindrance effect of the drainage structure on the zinc-based metal melt is aggravated. If the distance is set too large, the impact force of the zinc-based metal melt is large, reducing the uniformity of the melt distribution by the drainage structure. Secondly, there is a similar principle in the flow rate control of the zinc-based metal melt and the distance between the outlet of the zinc-based metal melt and the disc. If the flow rate of the zinc-based metal melt is small, the preparation efficiency is reduced. If the flow rate is too large, some unallocated fluid will cross the drainage structure, causing the drainage structure to fail.

[0031] The "free vertical falling distance" in the present invention is the vertical distance that the zinc-based metal melt flows out from the outlet of the melting furnace and impacts the center of the disc under the action of gravity after passing through a vertical distance. This vertical distance is the free vertical falling distance, which is used to accelerate the fluid so that the zinc-based metal melt has a certain impact force when contacting the center of the disc.

[0032] Specifically, the rotation speed of the disc is 20000 rpm - 60000 rpm.

[0033] Specifically, as Figure 2 shown, the drainage structure 010 is a hemispherical protrusion provided in the impact area 01. The diameter of the hemispherical protrusion is 0.5 mm - 2.5 mm, and as it moves away from the center of the disc, the diameter of the hemispherical protrusion gradually increases. Preferably, the diameter difference between the outermost radial protrusion and the innermost layer is not less than 1 mm to ensure that the drainage structure properly blocks the zinc-based metal melt to increase the uniformity of the same radial distribution of the zinc-based metal melt in the advection zone. Preferably, the diameter of the impact area 01 is 1.2 - 1.5 times the diameter of the incoming zinc-based metal melt, ensuring that the incoming zinc-based metal melt is within the range of the impact area 01 and has a good flow splitting effect. As Figure 2 shows a multi-layer of hemispherical protrusions arranged in a circle. With the center of the disc as the center of the circle, the diameters of the hemispherical protrusions on the same radius are the same. Preferably, in the same layer, the gap between two hemispherical protrusions is not less than half of the diameter of the hemispherical protrusions in this layer and not greater than the diameter of the hemispherical protrusions in this layer. Through the above structural limitations, combined with the distance between the outlet of the zinc-based metal melt of the present application and the disc and the flow rate of the zinc-based metal melt, it is ensured that the drainage structure always remains in the best state. It should be clear that the above size limitations are related to the zinc-based metal used in the invention embodiment and do not belong to the materials protected in the present application, and their physical properties such as viscosity cannot be adapted to the disc of the present application.

[0034] The disk preferably uses graphite material and heats the impact zone and the laminar flow zone, and the heating temperature is Tm + 5°C - Tm + 10°C, where Tm is the liquidus temperature of the zinc-based metal melt.

[0035] As Figure 3 shown, the secondary atomization zone 03 is connected to the laminar flow zone 02 through a connecting portion 04, and the circumferential sectional area of the connecting portion 04 accounts for no more than 1 / 10 of the circumferential area. By reducing the sectional area of the connecting portion 04, the heat transfer from the laminar flow zone 02 to the secondary atomization zone 03 is reduced. On the one hand, the present invention increases the uniformity of the zinc-based metal melt on the surface of the laminar flow zone 02 by setting a drainage structure, including the same thickness and speed of the metal melt on the same radius. If the secondary atomization zone is not set, due to the high temperature and low viscosity of the zinc-based metal melt, the high-speed metal droplets are likely to interact with the inert gas, increasing the generation probability of hollow powder. By setting the connecting portion, a gap is formed between the secondary atomization zone 03 and the laminar flow zone, facilitating a certain degree of cooling of the zinc-based metal melt split into small droplets at the end of the laminar flow zone. When the small droplets act on the secondary atomization zone, on the one hand, the speed of the small droplets is reduced, and on the other hand, the larger droplets are secondarily impacted and atomized to reduce the size of the liquid.

[0036] As Figure 4 described, the minimum distance between the secondary atomization zone 03 and the rotation axis forms a first distance L1, and the maximum distance between the laminar flow zone of the disk and the rotation axis forms a second distance L2. The difference ΔL between the first distance L1 and the second distance L2 is related to the second distance L2 and the rotation speed v of the disk; Specifically, the difference ΔL between the first distance and the second distance satisfies the following formula:

[0037] where L0 is the standard distance, is the correction coefficient, with the unit of mm, and v0 is the standard speed. In the embodiments of the present invention, the value range of is 18 mm - 22 mm. In the embodiments of the present invention, 20 mm is selected for calculation, the value of L0 is 50 mm, and the value of v0 is 20000 rpm.

[0038] As Figure 4As shown in the figure, the symmetry axis X1 of the radial cross-section of the secondary atomization zone 03 is perpendicular to and intersects with the rotation axis and is parallel to the surface of the co-current zone. The symmetry axis is located above the surface of the co-current zone, and there is a certain gap G between them. The size of the gap G is 0.01 mm - 0.05 mm. The secondary atomization zone 03 includes a flow-facing part 030 and a flow-guiding part 031. The surface of the radial cross-section of the flow-facing part 030 is the first arc A1. The center of curvature of the first arc A1 is set away from the disk center relative to the first arc, and the radius of curvature is 0.1 mm - 0.5 mm. The flow-guiding part 031 includes an upper flow-guiding part and a lower flow-guiding part. The surfaces of the radial cross-sections of the upper flow-guiding part and the lower flow-guiding part are the second arc A2. The center of curvature of the second arc A2 is set closer to the disk center relative to the second arc A2. The radius of curvature range of the second arc is 5 mm - 10 mm. The angle between the tangent line at the intersection of the second arc A2 and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disk and passing through the intersection point is 100° - 130°. Specifically, for the intersection point P1 of the second arc A2 and the upper surface of the secondary atomization zone, and the intersection point P2 of the second arc A2 and the lower surface of the secondary atomization zone. Taking the point P2 as an example, the angle α between the tangent line of the second arc A2 at the point P2 and the plane perpendicular to the rotation axis of the disk and passing through the intersection point is 100° - 130°. Since the rotation speed of the disk in this application is quite high, small-range changes in the above dimensions and angles are closely related to the quality of the finally prepared zinc-based spherical powder. First, in the technical solution of the present invention, the secondary atomization zone 03 guides the semi-solidified droplets after secondary atomization to flow out from both sides through the arcs on both sides of the symmetry axis X1, increasing the ejection area of the droplets. Compared with the prior art where droplets are only ejected from the edge, the collision probability between droplets is reduced, thereby reducing the generation of peanut-shaped powders. Secondly, the size of the gap G is 0.01 mm - 0.05 mm, and the radius of curvature of the first arc of the flow-facing part is 0.1 mm - 0.5 mm. The above size combination can reduce abnormal powders, that is, two droplets stick together, resulting in the prepared metal powder being peanut-shaped as Figure 5 As shown in the figure, the reason is that when the above dimensions are adopted, while ensuring the secondary impact atomization effect on the droplets, it enables good flow splitting effect of the droplets on both sides of the symmetry axis, that is, the upper and lower surfaces of the secondary atomization zone can have approximately the same droplet mass flow rate, and combined with the settings of the first arc and the second arc, the formation of dead zones is avoided.

[0039] In the embodiment of the present invention, the "disk center" refers to the central position of the rotating disk, that is, a point position; and the "rotation axis" is the rotation axis during the rotation of the disk, which is a virtual straight line.

[0040] The embodiment of the present invention also provides an orthopedic medical 3D printing zinc-based spherical powder, which is prepared by the above preparation method.

[0041] In order to qualitatively describe the prepared orthopedic medical 3D printing zinc-based spherical powder, the present invention adopts the following characterization methods: (1) Observe the morphology of the prepared zinc-based spherical powder by SEM.

[0042] (2) Count the number of hollow powders in at least 300 zinc-based spherical powders through an optical microscope, and calculate the hollow powder rate.

[0043] (3) Count the arrangement of the zinc-based spherical powder, obtain the D10 and D90 particle sizes, and calculate the particle size aggregation degree of the spherical powder.

[0044] (4) Test the loose bulk density of the zinc-based spherical powder by the funnel method (national standard GB / T 1479.1-2011). Test the fluidity of the zinc-based spherical powder by the standard funnel method (national standard GB / T 1482-2010). The smaller the loose bulk density value and the smaller the fluidity at the same time, it indicates that the powder particle size is more concentrated and the sphericity is better.

[0045] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0046] Example 1: An orthopedic medical 3D printing zinc-based spherical powder and a preparation method provided in this example, the zinc-based metal components are: Zn: 95%, Cu: 5.0%. It includes: S1. Prepare a zinc-based metal melt that meets the composition requirements. The liquidus temperature of the metal melt is 480°C, so it is sufficient to keep the temperature of the zinc-based metal melt at 490°C.

[0047] S2. Drain the zinc-based metal melt to the center of a high-speed rotating disk. After rotation acceleration, it splits, forms spheres, cools, and solidifies to obtain zinc-based spherical powder material.

[0048] The distance between the outlet of the zinc-based metal melt and the disk is 40 cm, the flow rate of the zinc-based metal melt is 4.0 kg / min, the rotation speed of the disk is 40000 rpm, and the heating temperature of the disk is 485°C.

[0049] The circumferential cross-sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0050] The second distance L2 of the present invention is 300 mm, and it is calculated by the formula

[0051] The size of ΔL is 3.6 mm. The axis of symmetry of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis and is parallel to the surface of the laminar flow zone. The axis of symmetry is located above the surface of the laminar flow zone, and there is a certain gap between them. The size of the gap is 0.03 mm. Both the first arc and the second arc are circular arcs. The radius of curvature of the first arc is 0.2 mm, and the radius of curvature of the second arc is 8 mm. The angle between the tangent line at the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 120°.

[0052] S3. Screen the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0053] Example 2: An orthopedic medical 3D printing zinc-based spherical powder and its preparation method provided in this example. The zinc-based metal components are: Zn: 95%, Cu: 5.0%. It includes: S1. Prepare a zinc-based metal melt that meets the composition requirements. The liquidus temperature of the metal melt is 480 °C, so just keep the temperature of the zinc-based metal melt at 490 °C.

[0054] S2. Drain the zinc-based metal melt to the center of a high-speed rotating disk. After the rotation accelerates, it splits, forms spheres, cools, and solidifies to obtain a zinc-based spherical powder material.

[0055] The distance between the outlet of the zinc-based metal melt and the disk is 30 cm. The flow rate of the zinc-based metal melt is 2.5 kg / min. The rotation speed of the disk is 20000 rpm. The heating temperature of the disk is 485 °C.

[0056] The circumferential sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0057] The second distance L2 of the present invention is 300 mm. Through formula calculation,

[0058] The size of ΔL is 4.7 mm. The axis of symmetry of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis and is parallel to the surface of the laminar flow zone. The axis of symmetry is located above the surface of the laminar flow zone, and there is a certain gap between them. The size of the gap is 0.03 mm. Both the first arc and the second arc are circular arcs. The radius of curvature of the first arc is 0.2 mm, and the radius of curvature of the second arc is 8 mm. The angle between the tangent line at the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 120°.

[0059] S3. Screen the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0060] Example 3: An orthopedic medical 3D printing zinc-based spherical powder and its preparation method provided in this example. The zinc-based metal components are: Zn: 95%, Cu: 5.0%. It includes: S1. Prepare a zinc-based metal melt that meets the composition requirements. The liquidus temperature of the metal melt is 480 °C, so it is sufficient to maintain the temperature of the zinc-based metal melt at 530 °C.

[0061] S2. Drain the zinc-based metal melt to the center of a high-speed rotating disk. After the rotation accelerates, it splits, forms spheres, cools, and solidifies to obtain zinc-based spherical powder material.

[0062] The distance between the outlet of the zinc-based metal melt and the disk is 50 cm, the flow rate of the zinc-based metal melt is 5.0 kg / min, the rotation speed of the disk is 60000 rpm, and the heating temperature of the disk is 485 °C.

[0063] The circumferential sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0064] The second distance L2 of the present invention is 300 mm. Through formula calculation,

[0065] The size of ΔL is 3.0 mm. The axis of symmetry of the radial section of the secondary atomization zone is perpendicular to and intersects the rotation axis and is parallel to the surface of the laminar flow zone. The axis of symmetry is located above the surface of the laminar flow zone, and there is a certain gap between them. The size of the gap is 0.03 mm. Both the first arc and the second arc are circular arcs. The curvature radius of the first arc is 0.2 mm, and the curvature radius of the second arc is 8 mm. The angle between the tangent of the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 120°.

[0066] S3. Screen the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0067] Example 4: Different from Example 1, in step S2 of this example, the circumferential sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0068] The second distance L2 of the present invention is 50 mm. Through formula calculation,

[0069] The dimension of ΔL is 5.7 mm. The axis of symmetry of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis, and is parallel to the surface of the co-current zone. The axis of symmetry is located above the surface of the co-current zone, and there is a certain gap between them. The size of the gap is 0.01 mm. Both the first arc and the second arc are circular arcs. The radius of curvature of the first arc is 0.1 mm, and the radius of curvature of the second arc is 5 mm. The angle between the tangent line at the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 100°.

[0070] Example 5: Different from Example 1, in step S2 of this example, the circumferential sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0071] The second distance L2 of the present invention is 200 mm, and it is calculated by the formula.

[0072] The dimension of ΔL is 4 mm. The axis of symmetry of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis, and is parallel to the surface of the co-current zone. The axis of symmetry is located above the surface of the co-current zone, and there is a certain gap between them. The size of the gap is 0.05 mm. Both the first arc and the second arc are circular arcs. The radius of curvature of the first arc is 0.5 mm, and the radius of curvature of the second arc is 10 mm. The angle between the tangent line at the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 130°.

[0073] Example 6: An orthopedic medical 3D printing zinc-based spherical powder and its preparation method provided in this example. The zinc-based metal components are: Zn: 96%, Al: 4.0%. It includes: S1. Prepare a zinc-based metal melt that meets the compositional requirements. The liquidus temperature of the metal melt is 675 °C, so it is sufficient to maintain the temperature of the zinc-based metal melt at 685 °C.

[0074] S2. Drain the zinc-based metal melt to the center of a high-speed rotating disk. After the rotation accelerates, it splits, forms spheres, cools, and solidifies to obtain zinc-based spherical powder materials.

[0075] The distance between the outlet of the zinc-based metal melt and the disk is 40 cm. The flow rate of the zinc-based metal melt is 4.0 kg / min. The rotation speed of the disk is 40000 rpm. The heating temperature of the disk is 680 °C.

[0076] The circumferential sectional area of the disk connection part accounts for 1 / 12 of the circumferential area.

[0077] The second distance L2 of the present invention is 300 mm. Through formula calculation,

[0078] The size of ΔL is 3.6 mm. The symmetry axis of the radial cross-section of the secondary atomization zone is perpendicular to and intersects with the rotation axis and is parallel to the surface of the co-current zone. The symmetry axis is located above the surface of the co-current zone, and there is a certain gap between them. The size of the gap is 0.03 mm. Both the first arc and the second arc are circular arcs. The curvature radius of the first arc is 0.2 mm, and the curvature radius of the second arc is 8 mm. The angle between the tangent line of the intersection points of the second arc with the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the disk rotation axis and passing through the intersection points is 120°.

[0079] S3. Screen the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0080] Comparative Example 1: Different from Example 1, the disk in this comparative example does not have a secondary atomization zone.

[0081] Comparative Example 2: Different from Example 1, in this comparative example, the distance between the outlet of the zinc-based metal melt and the disk is 60 cm, and the flow rate of the zinc-based metal melt is 6 kg / min.

[0082] Comparative Example 3: Different from Example 1, in this comparative example, the rotation speed of the disk is 15000 rpm.

[0083] Comparative Example 4: Different from Example 1, in this comparative example, the rotation speed of the disk is 70000 rpm.

[0084] Comparative Example 5: Different from Example 1, in this comparative example, the size of ΔL is 3 mm.

[0085] Comparative Example 6: Different from Example 1, in this comparative example, the size of ΔL is 4 mm Comparative Example 7: Different from Example 1, in this comparative example, there is no first arc, that is, the second arc is directly intersected.

[0086] Comparative Example 8: Different from Example 1, in this comparative example, the curvature radius of the second arc is 12 mm.

[0087] Since the SEM diagrams of the zinc-based spherical powders prepared in Examples 1-6 are similar, Example 1 is taken as a typical representative for description. As Figure 6 shown in a and b of, the prepared zinc-based spherical powder has a high sphericity and there is no peanut-shaped powder. It shows that the technical solution provided by the present invention can greatly reduce the collision probability of droplets after leaving the turntable.

[0088] The zinc-based spherical powder prepared in Comparative Example 1 is as shown in Figure 7 a and b therein. It can be seen that the lack of a secondary atomization zone results in an excessive number of hollow powders in the prepared zinc-based spherical powder. The reason is that after the metal melt splits at the edge of the disk and interacts with the inert gas medium, the viscosity of the metal droplets is low at this time, resulting in their being impacted by the gas and generating hollow powders. Secondly, peanut-shaped powders also exist in the prepared powders.

[0089] The zinc-based spherical powders prepared in Examples 1-6 and Comparative Examples 1-8 were characterized, and the test data obtained are shown in Table 1.

[0090] Table 1 Performance test data of each example and comparative example

[0091] It can be seen from the above data that the technical solutions provided in the embodiments of the present invention have the characteristics of a small hollow ratio, high powder particle size concentration, and good fluidity. From Example 1 and Comparative Example 1, it can be seen that the setting of the secondary atomization zone can significantly reduce the hollow powder ratio and powder particle size concentration, and has good fluidity, while the poor powder particle size concentration leads to a higher loose bulk density. From Example 1 and Comparative Example 2, it can be seen that the distance between the outlet of the zinc-based metal melt and the disk and the flow rate of the zinc-based metal melt will also deteriorate the quality of the prepared zinc-based metal powder. The reason is that the large melt impact force and high flow rate limit the flow limiting and flow equalizing effects of the impact zone, resulting in a high hollow ratio, large particle size concentration, large loose bulk density, and weak fluidity of the prepared powder. From Example 1, Comparative Examples 3 and 4, it can be seen that the rotation speed of the disk will also affect the quality of the zinc-based metal powder. Both a small rotation speed and a large rotation speed weaken the flow equalizing effect of the impact zone, thereby reducing the quality of the zinc-based metal powder. From Example 1, Comparative Examples 5 and 6, it can be seen that the size of ΔL is very crucial. If the size is too small, the cooling intensity of the droplets ejected from the advection zone is low, resulting in an increase in the hollow powder ratio. If the size is too large, the cooling intensity is too high, and the secondary atomization effect is weakened, resulting in an increase in the loose bulk density and a deterioration in fluidity. It can be seen from Example 1 and Comparative Example 7 that the upstream part is very important. The upstream part is mainly used for secondary atomization and reducing the droplet speed. The absence of the upstream part results in a significant increase in the hollow powder ratio, a decrease in the concentration of the powder particle size distribution, and a deterioration in fluidity. From Example 1 and Comparative Example 8, it can be seen that the curvature radius of the second arc is large, which affects the flow field in cooperation with the first arc, and some dead zones are formed, resulting in a significant reduction in the powder fluidity.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of an orthopedic medical 3D printing zinc-based spherical powder, characterized in that, Comprising: Preparing a zinc-based metal melt that meets the composition requirements; Draining the zinc-based metal melt to the center of a high-speed rotating disk. After rotation acceleration, it splits, forms spheres, cools, and solidifies to obtain zinc-based spherical powder material; Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder; In the zinc-based metal, by mass percentage, Cu: 0.1% - 7.0%, Mg: 0.02% - 0.10%, Al: 3.5% - 4.5%, Li ≤ 0.01%, Mn ≤ 0.02%, and the rest is Zn; The disk has an impact zone, a laminar flow zone, and a secondary atomization zone; The impact zone is located in the middle of the disk and is used to receive the zinc-based metal melt. The impact zone has a drainage structure; The laminar flow zone is annular and is located on the side of the disk away from the disk center; The secondary atomization zone is annular and is located on the side away from the disk center relative to the laminar flow zone.

2. The preparation method according to claim 1, wherein The temperature of the zinc-based metal melt is Tm + 10°C - Tm + 50°C, where Tm is the liquidus temperature of the zinc-based metal melt.

3. The preparation method according to claim 1, wherein The free vertical falling distance of the zinc-based metal melt is 30 cm - 50 cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min - 5.0 kg / min.

4. The preparation method according to claim 1, wherein The rotation speed of the disk is 20000 rpm - 60000 rpm.

5. The preparation method according to claim 1, wherein The drainage structure is a hemispherical protrusion provided in the impact zone. The diameter of the hemispherical protrusion is 0.5 mm - 2.5 mm, and as it moves away from the disk center, the diameter of the hemispherical protrusion gradually increases.

6. The preparation method according to claim 5, wherein The impact zone and the laminar flow zone are heated, and the heating temperature is Tm + 5°C - Tm + 10°C, where Tm is the liquidus temperature of the zinc-based metal melt.

7. The preparation method according to claim 6, wherein The secondary atomization zone is connected to the laminar flow zone through a connecting part, and the circumferential sectional area of the connecting part accounts for no more than 1 / 10 of the circumferential area.

8. The preparation method according to claim 7, wherein The minimum distance between the secondary atomization zone and the rotation axis forms a first distance, and the maximum distance between the laminar flow zone of the disk and the rotation axis forms a second distance. The difference between the first distance and the second distance is related to the second distance and the rotation speed of the disk; The difference ΔL between the first distance and the second distance satisfies the following formula: where L2 is the second distance, and L0 is the standard distance, is the correction coefficient, with the unit of mm, v is the rotational speed of the disk, and v0 is the standard speed.

9. The preparation method according to claim 8, wherein The symmetry axis of the radial section of the secondary atomization zone is perpendicular to and intersects with the rotation axis and is parallel to the surface of the laminar flow zone. The symmetry axis is located above the surface of the laminar flow zone, and there is a gap between them. The size of the gap is 0.01 mm - 0.05 mm; The secondary atomization zone includes a flow-facing portion and a flow-guiding portion. The surface of the radial cross-section of the flow-facing portion is a first arc, and the center of curvature of the first arc is arranged away from the center of the disc relative to the first arc and the radius of curvature is 0.1 mm - 0.5 mm; The flow-guiding portion includes an upper flow-guiding portion and a lower flow-guiding portion. The surfaces of the radial cross-sections of the upper flow-guiding portion and the lower flow-guiding portion are second arcs. The center of curvature of the second arc is arranged close to the center of the disc relative to the second arc, and the radius of curvature of the second arc ranges from 5 mm to 10 mm; the angle between the tangent line at the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 100° - 130°.

10. An orthopedic medical 3D printing zinc-based spherical powder, characterized in that, The orthopedic medical 3D printing zinc-based spherical powder is prepared by using the preparation method according to any one of claims 1 - 9.

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