A biomedically degradable Zn-Cu-Ca alloy, a preparation method and application thereof

Abstract

This invention relates to a biodegradable Zn-Cu-Ca alloy for biomedical use, its preparation method, and its applications. It pertains to the field of biomedical materials, particularly zinc alloys. The Zn-Cu-Ca alloy comprises Zn, Cu, and Ca, with Cu content ranging from 0.05 to 3.0 wt%, Ca content from 0.05 to 2.0 wt%, and the remainder being Zn. This invention successfully prepares the Zn-Cu-Ca alloy using alloy ingots and a remelting method. By rationally designing the alloy composition, this invention significantly improves the alloy's mechanical properties and biodegradability. The addition of copper enhances the alloy's strength, while the addition of calcium regulates the degradation rate and improves biocompatibility. This alloy material is suitable for the biomedical field, especially as a biodegradable implant material, and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, particularly the field of zinc alloys, and specifically relates to a biomedical biodegradable Zn-Cu-Ca alloy, its preparation method, and its application. Background Technology

[0002] Zinc-based alloys, as a novel type of biodegradable metal, possess excellent biocompatibility, a moderate degradation rate, and low biotoxicity, making them a hot research topic in the biomedical field in recent years. Compared with traditional magnesium and iron alloys, zinc alloys exhibit a more moderate degradation process, and their degradation product—zinc ions—can be effectively metabolized by the body without producing harmful side effects. This gives zinc-based alloys significant advantages in the biomedical field, particularly in the application of implants such as bone repair and vascular stents.

[0003] However, despite the broad application prospects of zinc-based alloys in the biomedical field, their mechanical properties and degradation behavior remain significant factors limiting their application. Both excessively rapid and excessively slow degradation rates of zinc-based alloys can lead to functional failure of implants within the body. Therefore, precisely controlling the degradation rate of zinc-based alloys to ensure adequate support during implantation and gradual degradation after repair has become a crucial research direction. Simultaneously, the mechanical properties of zinc-based alloys, such as tensile strength, hardness, and ductility, are typically low, making it difficult to meet the requirements of implants. Therefore, improving the mechanical properties of zinc alloys, especially optimizing them while ensuring biodegradability, has become a focus of zinc-based alloy research in recent years.

[0004] To address these issues, numerous researchers have conducted extensive work on the alloying design and preparation processes of zinc alloys. For example, adding elements such as copper and calcium to zinc alloys can effectively improve their mechanical properties and degradation behavior. The addition of copper can balance the strengthening and toughening effects of zinc alloys while enhancing their antibacterial properties, while the addition of calcium can regulate their degradation rate, ensuring the controllability of their degradation in vivo. Furthermore, some studies have successfully explored methods such as grain refinement and surface modification to further improve the mechanical properties and biocompatibility of zinc alloys.

[0005] While these studies have provided new ideas and methods for the application of zinc alloys, many challenges remain. First, the influence of the proportions and ratios of different alloying elements on the alloy properties is not yet fully understood, and alloy design and optimization still require further in-depth research. Second, existing preparation processes such as casting and heat treatment, while improving the properties of zinc alloys to some extent, are still insufficient to fully meet the requirements of high-performance biomedical implants. Therefore, developing more efficient and precise alloying design and preparation processes has become an important direction for zinc-based alloy research.

[0006] In summary, zinc-based alloys, as biodegradable metallic materials, have broad application potential, especially in biomedical fields such as bone repair and vascular stents. However, to fully realize their potential, in-depth research and exploration are still needed in areas such as alloying design, preparation processes, and performance optimization to achieve their widespread clinical application. Summary of the Invention

[0007] The purpose of this invention is to provide a biodegradable Zn-Cu-Ca alloy for biomedical use, its preparation method, and its application. By optimizing the preparation method and formulation of the Zn-Cu-Ca alloy, it is expected to solve the problems of slow corrosion degradation, difficulty in controlling degradation, and poor cell compatibility of biodegradable zinc alloys.

[0008] The present invention achieves the above objectives through the following technical solutions:

[0009] A method for preparing a biodegradable Zn-Cu-Ca alloy for biomedical use, wherein the Zn-Cu-Ca alloy comprises Zn, Cu, and Ca, wherein the Cu content is 0.05-3.0 wt%, the Ca content is 0.05-2.0 wt%, and the remainder is Zn; the preparation method includes the following steps:

[0010] (1) Pure Zn spheres, Zn-(2-4)Cu intermediate alloy, and pure calcium particles are selected for batching;

[0011] (2) Melt the ingredients at a temperature of 500-600℃ to obtain Zn metal melt;

[0012] (3) Pour the Zn metal melt obtained in step (2) into the prepared mold, and after cooling, obtain Zn-Cu-Ca alloy ingot;

[0013] (4) The Zn-Cu-Ca alloy ingot is remelted in the furnace at a temperature of 430-480℃ and stirred to obtain a uniform melt. The melt is then cast and rapidly cooled to obtain a Zn-Cu-Ca alloy ingot with uniform composition.

[0014] (5) Plastic processing is performed on the Zn-Cu-Ca alloy ingot to obtain Zn-Cu-Ca alloy profile.

[0015] As a further optimization of the above invention, the Zn-Cu-Ca alloy composition contains 0.1-1.0 wt% Cu and 0.1-1.0 wt% Ca.

[0016] As a further optimization of the above invention, the Zn-Cu-Ca alloy composition has a Cu content of 0.6 wt% and a Ca content of 0.5 wt% or 0.2 wt%.

[0017] As a further optimization of the above invention, in step (3), a graphite mold is selected, the pouring temperature is controlled at 180-230℃, and low-temperature casting or semi-solid casting is adopted.

[0018] As a further optimization of the above invention, in step (4), the oxidation and dirt on the surface of the Zn-Cu-Ca alloy ingot are first removed by sandpaper or grinding wheel, and then it is remelted. Before the Zn-Cu-Ca alloy ingot is remelted, 0.05-0.5wt% of the alloy mass of the third component X is added. The third component X is added in the form of a metallic element, Zn-X alloy, compound or oxide. Specifically, the third component X is one of MgB2, Zn-1.0Li, Zn-0.5Mn, Zn-3Mn or Zn-2Mg.

[0019] As a further optimization of the above invention, in step (5), the plastic processing is one or more of the following: rotary forging, extrusion, rolling, drawing or equal diameter angular extrusion; the temperature of the plastic processing is 100-300℃.

[0020] As a further optimization of the above invention, Zn-Cu-Ca alloy profiles include rods, plates, and foils.

[0021] The present invention also provides a biodegradable Zn-Cu-Ca alloy for biomedical use, which is prepared by the above preparation method.

[0022] This invention also provides the application of the above-mentioned Zn-Cu-Ca biodegradable zinc alloy in the preparation of bioactive implantable devices, including its application in the preparation of orthopedic implantable devices and bioactive membranes / patches.

[0023] The orthopedic implant body includes at least one of bone plates, bone screws, bone tissue repair scaffolds, intramedullary nails, bone sheaths, or spinal fixation devices; the bioactive membrane / patch includes at least one of guiding bone regeneration membranes, guiding tissue regeneration membranes, hernia patches, fistula patches, or oral / dental barrier membranes.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) Cu and Ca improve the biological properties of zinc alloys: Copper (Cu) and calcium (Ca) are both important elements in the human body. Cu participates in a variety of physiological functions, such as promoting blood circulation and cell function, while Ca is an essential element for bone growth and repair. By introducing Cu and Ca into Zn alloys, their biocompatibility can be improved and their tissue repair function can be enhanced.

[0026] (2) Cu and Ca accelerate and regulate the corrosion degradation behavior of zinc alloys: The addition of Cu and Ca can significantly improve the corrosion degradation behavior of zinc alloys. The addition of Cu can form CuZn4 phase, which further accelerates the degradation process of the alloy, while Ca helps to improve the stability and mechanical properties of the alloy in the biological environment.

[0027] (3) Successful preparation of Zn-Cu-Ca alloy by alloy ingot + remelting method: As mentioned above, Cu and Ca have high activity. Therefore, by using the "alloy ingot + remelting" method, the evaporation loss of Cu and Ca can be effectively avoided, ensuring the high quality and stability of Zn-Cu-Ca alloy.

[0028] (4) By “composition design (Cu / Ca ratio), addition of third component, and optimization of alloy ingot + remelting process”, a balance between biocompatibility, mechanical properties and degradation performance of zinc-copper alloy was achieved.

[0029] In summary, the successfully prepared high-quality Zn-Cu-Ca zinc alloy is expected to solve the problems of slow corrosion degradation, difficult degradation control, and poor cell compatibility of biodegradable zinc alloys. It is also expected to improve its bioactivity, enhance the level of disease treatment, and bring better potential clinical benefits. Attached Figure Description

[0030] Figure 1 The microstructures of as-cast Zn-0.6Cu(a), Zn-0.6Cu-0.2Ca(b), and Zn-0.6Cu-0.5Ca(c) are shown.

[0031] Figure 2 SEM images of forged Zn-0.6Cu alloys with different Ca contents: Zn-0.6Cu (a, b), Zn-0.6Cu-0.2Ca (c), Zn-0.6Cu-0.5Ca (d);

[0032] Figure 3 (a) Microstructure and (b) XRD pattern of Zn-Cu-Ca alloy (compared with pure Zn);

[0033] Figure 4 EBSD grain orientation diagrams of Zn-0.6Cu(a), Zn-0.6Cu-0.2Ca(b), and Zn-0.6Cu-0.5Ca(c) alloys in the spin-forged state;

[0034] Figure 5 The EBSD texture distribution diagrams are shown for Zn-0.6Cu alloy samples with different Ca contents in the forged state.

[0035] Figure 6Tensile properties of Zn-0.6Cu alloy samples with different Ca contents: (a) tensile engineering stress-strain curves of cast C and rotary forged S alloys; (b) tensile engineering stress-strain curves of cast C alloy; (c) yield strength, ultimate tensile strength and elongation of rotary forged alloys.

[0036] Figure 7 Fracture morphologies of forged Zn-0.6Cu alloys with different Ca contents after room temperature tensile testing: (a) 0; (b) 0.2 wt%; (c) 0.5 wt%.

[0037] Figure 8 The effect of different Ca contents on the Vickers hardness of forged Zn-0.6Cu alloy samples;

[0038] Figure 9 The surface microstructures of (a,d,g,j)Zn-0.6Cu, (b,e,h,k)Zn-0.6Cu-0.2Ca, and (c,f,I,l)Zn-0.6Cu-0.5Ca after soaking for 3, 7, 14, and 28 days are shown.

[0039] Figure 10 Electrochemical experimental results of the forged Zn-0.6Cu alloy sample: (a) Potentiodynamic polarization curve; (b) Electrochemical impedance spectroscopy-Bode phase angle diagram; (c) Electrochemical impedance spectroscopy; (d) Electrochemical impedance spectroscopy-Bode impedance modulus diagram.

[0040] Figure 11 Photographs of the inhibition zones of Zn-0.6Cu, Zn-0.6Cu-0.2Ca, Zn-0.6Cu-0.5Ca, pure zinc control group, and pure titanium control group against Escherichia coli in the spin-forged state;

[0041] Figure 12 Photographs of the inhibition zones of Staphylococcus aureus in the following conditions: (a) Zn-0.6Cu; (b) Zn-0.6Cu-0.2Ca; (c) Zn-0.6Cu-0.5Ca; (d) pure zinc control group; (e) pure titanium control group. Detailed Implementation

[0042] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0043] I. Explanation

[0044] At least one embodiment of the present invention discloses a bioactive Zn-Cu-Ca biodegradable zinc alloy, comprising Zn, Cu, and Ca, wherein the Cu content is 0.05-3.0 wt%, the Ca content is 0.05-2.0 wt%, and the remainder is Zn. Preferably, the biodegradable zinc alloy contains 0.1-1.0 wt% Cu and 0.1-1.0 wt% Ca.

[0045] The preparation method of the above-mentioned Zn-Cu-Ca biodegradable zinc alloy includes the following steps:

[0046] (1) Pure Zn spheres, Zn-(2-4)Cu intermediate alloy, and pure calcium particles are selected for batching;

[0047] (2) Melt the ingredients at a temperature of 500-600℃ to obtain Zn metal melt;

[0048] (3) Pour the Zn metal melt obtained in step (2) into the prepared mold, and after cooling, obtain Zn-Cu-Ca alloy ingot;

[0049] (4) The Zn-Cu-Ca alloy ingot is remelted in the furnace at a temperature of 430-480℃ and stirred to obtain a uniform melt. The melt is then cast and rapidly cooled to obtain a Zn-Cu-Ca alloy ingot with uniform composition.

[0050] (5) Plastic processing is performed on the Zn-Cu-Ca alloy ingot to obtain Zn-Cu-Ca alloy profile.

[0051] In step (2), smelting is carried out in a medium-frequency induction furnace.

[0052] In step (3), a graphite mold is selected, the pouring temperature is controlled at 180-230℃, and low-temperature casting or semi-solid casting is adopted.

[0053] In step (4), first use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of the Zn-Cu-Ca alloy ingot, and then remelt it in the furnace.

[0054] In step (4), before the Zn-Cu-Ca alloy ingot is remelted, 0.05-0.5 wt% of a third component X by weight of the alloy can be added. The third component X can be added as a metallic element, a Zn-X alloy, a compound, or an oxide, etc. The third component X is selected from at least one of Li, Mg, Ca, Sr, Mn, Fe, Cu, Ge, Sn, B, Si, C, N, and O. For example, MgB2, Zn-1.0Li, Zn-0.5Mn, Zn-3Mn, and Zn-2Mg.

[0055] In step (4), the stirring is either electromagnetic stirring or mechanical stirring.

[0056] In step (4), the rapid cooling method after the melt is cast can be forced convection cooling, water cooling or oil cooling.

[0057] In step (5), plastic processing is one or more of the following processing methods: rotary forging, extrusion, rolling, drawing or equal diameter angular extrusion; the temperature of plastic processing is 100-300℃.

[0058] In step (5), the obtained Zn-Cu-Ca alloy profiles include rods, plates, and foils.

[0059] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products, and all instruments used are conventional instruments known to those skilled in the art.

[0060] II. Experimental Preparation

[0061] Example 1

[0062] The zinc alloy Zn-2Cu-0.5Ca in this embodiment comprises Zn, Cu, and Ca, wherein Cu content is 2 wt%, Ca content is 0.5 wt%, and the remainder is Zn. The preparation method includes the following steps:

[0063] (1) Pure Zn spheres, Zn-2Cu intermediate alloy, and pure calcium particles are selected for the batching;

[0064] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C to obtain Zn metal melt;

[0065] (3) Pour the Zn metal melt obtained in step (2) into a graphite mold, control the pouring temperature to 220℃, use low temperature casting, and after cooling, obtain Zn-Cu-Ca alloy ingot.

[0066] (4) First, use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of Zn-Cu-Ca alloy ingot. Add 0.2wt% of the third component Zn-3Mn by alloy mass. Then, remelt the Zn-Cu-Ca alloy ingot at 450℃ and stir to obtain a uniform melt. After casting, the melt is cooled quickly to obtain a Zn-Cu-Ca alloy ingot with uniform composition.

[0067] (5) The Zn-Cu-Ca alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu-Ca alloy rods.

[0068] Example 2

[0069] The zinc alloy Zn-0.6Cu-0.5Ca in this embodiment comprises Zn, Cu, and Ca, wherein the Cu content is 0.6 wt%, the Ca content is 0.5 wt%, and the remainder is Zn. The preparation method includes the following steps:

[0070] (1) Pure Zn spheres, Zn-2Cu intermediate alloy, and pure calcium particles are selected for the batching;

[0071] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C to obtain Zn metal melt;

[0072] (3) Pour the Zn metal melt obtained in step (2) into a graphite mold, control the pouring temperature to 220℃, use low temperature casting, and after cooling, obtain Zn-Cu-Ca alloy ingot.

[0073] (4) First, use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of Zn-Cu-Ca alloy ingot. Add 0.2wt% of the third component MgB2 of the alloy mass. Then, remelt the Zn-Cu-Ca alloy ingot at 450℃ and stir to obtain a uniform melt. After casting, the melt is cooled quickly to obtain a Zn-Cu-Ca alloy ingot with uniform composition.

[0074] (5) The Zn-Cu-Ca alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu-Ca alloy rods.

[0075] Example 3

[0076] In this embodiment, the zinc alloy Zn-0.6Cu-0.5Ca is extruded at 300℃ and at an extrusion speed of 10mm / s in step (5) to obtain Zn-Cu-Ca alloy rods. The rest is the same as in Example 2.

[0077] Example 4

[0078] In this embodiment, the zinc alloy Zn-0.6Cu-0.5Ca is used. In step (4), 0.2wt% of the third component Zn-1.0Li is added to obtain Zn-Cu-Ca alloy rods. The rest is the same as in Example 2.

[0079] Example 5

[0080] In this embodiment, the zinc alloy Zn-0.6Cu-0.5Ca is used. In step (4), 0.2wt% of the third component Zn-2Mg is added to obtain Zn-Cu-Ca alloy rods. The rest is the same as in Example 2.

[0081] Example 6

[0082] In this embodiment, the zinc alloy Zn-0.6Cu-0.5Ca is obtained without adding a third component in step (4), and the rest is the same as in embodiment 2.

[0083] Example 7

[0084] The zinc alloy Zn-0.6Cu-0.2Ca in this embodiment comprises Zn, Cu, and Ca, wherein the Cu content is 0.6 wt%, the Ca content is 0.2 wt%, and the remainder is Zn. The preparation method includes the following steps:

[0085] (1) Pure Zn spheres, Zn-2Cu intermediate alloy, and pure calcium particles are selected for the batching;

[0086] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C to obtain Zn metal melt;

[0087] (3) Pour the Zn metal melt obtained in step (2) into a graphite mold, control the pouring temperature to 220℃, use low temperature casting, and after cooling, obtain Zn-Cu-Ca alloy ingot.

[0088] (4) First, use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of Zn-Cu-Ca alloy ingot. Add 0.2wt% of the third component Zn-1.0Li and Zn-0.5Mn (equal amounts) according to the alloy mass. Then, remelt the Zn-Cu-Ca alloy ingot at 450℃ and stir to obtain a uniform melt. After casting, the melt is cooled quickly to obtain a Zn-Cu-Ca alloy ingot with uniform composition.

[0089] (5) The Zn-Cu-Ca alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu-Ca alloy rods.

[0090] Example 8

[0091] In this embodiment, the zinc alloy Zn-0.6Cu-0.2Ca is drawn at 300℃ in step (5), with a drawing speed of 5mm / s and a total deformation controlled at 60%, to obtain Zn-Cu-Ca alloy rods. The rest is the same as in Example 7.

[0092] Example 9

[0093] In this embodiment, the zinc alloy Zn-0.6Cu-0.2Ca is used. In step (4), 0.2wt% of the third component MgB2 is added to obtain Zn-Cu-Ca alloy rods. The rest is the same as in Example 7.

[0094] Example 10

[0095] The zinc alloy Zn-2Cu-0.2Ca in this embodiment comprises Zn, Cu, and Ca, wherein the Cu content is 2 wt%, the Ca content is 0.2 wt%, and the remainder is Zn. The preparation method is the same as in Example 2.

[0096] Example 11

[0097] The zinc alloy Zn-0.6Cu-0.1Ca in this embodiment comprises Zn, Cu, and Ca, with Cu content of 0.6 wt%, Ca content of 0.1 wt%, and the remainder being Zn. The preparation method is the same as in Example 2.

[0098] Example 12

[0099] The zinc alloy Zn-1Cu-0.2Ca in this embodiment comprises Zn, Cu, and Ca, wherein the Cu content is 1 wt%, the Ca content is 0.2 wt%, and the remainder is Zn. The preparation method is the same as in Example 2.

[0100] Example 13

[0101] The zinc alloy Zn-1Cu-2Ca in this embodiment comprises Zn, Cu, and Ca, with Cu content of 1 wt%, Ca content of 2 wt%, and the remainder being Zn. The preparation method is the same as in Example 2.

[0102] Comparative Example 1

[0103] The zinc alloy Zn-0.6Cu in this comparative example comprises Zn and Cu, with Cu accounting for 0.6 wt% and the remainder being Zn. The preparation method includes the following steps:

[0104] (1) Pure Zn spheres and Zn-2Cu intermediate alloy were selected for batching;

[0105] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C to obtain Zn metal melt;

[0106] (3) Pour the Zn metal melt obtained in step (2) into a graphite mold, control the pouring temperature to 220°C, use low temperature casting or semi-solid casting, and after cooling, obtain Zn-Cu alloy ingot.

[0107] (4) First, use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of Zn-Cu alloy ingot. Then, remelt the Zn-Cu alloy ingot at 450℃ and stir to obtain a uniform melt. After casting, the melt is cooled quickly to obtain a Zn-Cu alloy ingot with uniform composition.

[0108] (5) The Zn-Cu alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu alloy rods.

[0109] Comparative Example 2

[0110] The zinc alloy Zn-2Cu in this comparative example contains Zn and Cu, with Cu accounting for 2 wt% and the remainder being Zn. The preparation method is the same as in Comparative Example 1.

[0111] Comparative Example 3

[0112] The zinc alloy Zn-0.6Cu-0.2Ca in this comparative example comprises Zn, Cu, and Ca, with Cu content of 0.6 wt%, Ca content of 0.2 wt%, and the remainder being Zn. The preparation method includes the following steps:

[0113] (1) Pure Zn spheres, Zn-2Cu intermediate alloy, and pure calcium particles are selected for the batching;

[0114] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C. 0.2 wt% of the total mass of the ingredients is added as the third component MgB2 to obtain Zn metal melt.

[0115] (3) Pour the Zn metal melt obtained in step (2) into a graphite mold, control the pouring temperature to 220℃, use low temperature casting, and after cooling, obtain Zn-Cu-Ca alloy ingot.

[0116] (4) The Zn-Cu-Ca alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu-Ca alloy rods.

[0117] Comparative Example 4

[0118] The zinc alloy Zn-0.6Cu-0.2Ca-0.2Mg in this comparative example comprises Zn, Cu, and Ca, with Cu content of 0.6 wt%, Ca content of 0.2 wt%, Mg content of 0.2 wt%, and the remainder being Zn. The preparation method includes the following steps:

[0119] (1) Pure Zn spheres, Zn-2Cu intermediate alloy, pure calcium particles, and pure magnesium powder are selected for the formulation.

[0120] (2) The ingredients are put into a medium-frequency induction furnace and smelted at 600°C to obtain Zn metal melt;

[0121] (3) The Zn metal melt obtained in step (2) is poured into a graphite mold, the pouring temperature is controlled at 220℃, and low-temperature casting is adopted. After cooling, Zn-Cu-Ca-Mg alloy ingot is obtained.

[0122] (4) First, use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of Zn-Cu-Ca-Mg alloy ingot. Add 0.1wt% of the third component MgB2 according to the alloy mass. Then, remelt the Zn-Cu-Ca-Mg alloy ingot at 450℃ and stir to obtain a uniform melt. After casting, the melt is cooled quickly to obtain a Zn-Cu-Ca-Mg alloy ingot with uniform composition.

[0123] (5) The Zn-Cu-Ca-Mg alloy ingot is subjected to rotary forging at 300℃ with an initial rotary wheel speed of 300r / min, a feed rate of 2mm / r, an error within 1mm, and a total deformation of 60% to obtain Zn-Cu-Ca-Mg alloy rods.

[0124] III. Performance

[0125] 1. Microstructure characterization

[0126] (1) Optical microscopic tissue observation

[0127] The sample was ground and polished. After treatment, the sample surface was etched with a 4% (v / v) nitric acid-alcohol solution for 10-15 seconds. After completion, it was rinsed with water and anhydrous alcohol in sequence and then dried. The etched sample surface was observed under a Leica metallographic microscope. When a region with clear grain boundaries was observed, it was photographed and the corresponding scale was marked.

[0128] (2) Electron backscattering diffraction analysis

[0129] The sample to be observed was electropolished using a DC current source after mechanical grinding and polishing. The processed sample, with an initial rotary forging speed of 300 r / min, a feed rate of 2 mm / r, and an error within 1 mm, was then subjected to EBSD testing on a FEI Helios Nanolab 600i scanning electron microscope. The obtained data were analyzed using Aztec Crystal software.

[0130] (3) SEM observation

[0131] Three different Ca contents were forged after fine grinding, polishing, and etching. The initial rotary wheel speed was 300 r / min, the feed rate was 2 mm / r, and the error was within 1 mm. The alloy microstructure of the samples was observed using a field emission scanning electron microscope (TESCAN MIRA3), and the phase composition of the samples was determined and analyzed using the equipped energy dispersive spectroscopy analyzer.

[0132] like Figure 1 As shown, a small amount of white CuZn4 phase can be observed in the microstructure of the Zn-0.6Cu (Comparative Example 1) sample. After the introduction of Ca, it can be observed that with the increase of Ca content, the content of the second phase in the matrix increases significantly, and a cuboid CaZn phase appears. 13 The phases gradually increase in size and decrease in size as the Ca content increases, indicating that the increase in Ca content leads to changes in phase size.

[0133] like Figure 2 As shown, with the increase of Ca content, CaZn 13 The number of phases gradually increases. Simultaneously, the area scan distribution image reveals that in CaZn... 13 The second phase contains a small amount of Cu, but CuZn4 does not contain Ca.

[0134] like Figure 3 As shown, comparing Zn-2Cu (Comparative Example 2) with Zn-2Cu-0.5Ca (Example 1) and Zn-2Cu-0.2Ca (Example 10), the Cu content was the same, but the addition of Ca resulted in differences in the peak position / intensity of CuZn4, indicating that the addition of Ca altered the formation of the Cu-Zn phase or its crystal structure. Comparing Zn-2Cu-0.5Ca (Example 1) and Zn-2Cu-0.2Ca (Example 10), CaZn... 13 The peak weakens as the Ca content decreases, indicating that the Ca content directly affects the amount of this phase formed. Compared with Zn-2Cu (Comparative Example 2), Zn-0.6Cu (Comparative Example 1) has a higher Cu content and a stronger CuZn4 peak, indicating that the higher the Cu content, the more enriched the CuZn4 phase.

[0135] XRD patterns show that the Zn-0.6Cu-0.2Ca alloy phases include a Zn matrix, CuZn4, and CuZn. 13 Each phase exhibits good crystallinity and a complete structure, with phase composition and characteristic peak intensity well-matched, achieving a balance in performance. Mechanically, CuZn4 exhibits dispersion strengthening, while CuZn... 13 Synergistically optimized microstructure, balancing strength and toughness; during degradation, CuZn 13By utilizing micro-batteries and element release, the rate of corrosion can be regulated without excessive corrosion. In biomedical applications, Ca promotes bone repair, and the composition is balanced and non-toxic. Compared to alloys with other components, this alloy is superior in terms of phase synergy and the balance between mechanical, degradation, and biocompatibility, exhibiting outstanding overall performance.

[0136] like Figure 4 As shown, obvious columnar crystals or twins exist in the Zn-0.6Cu (Comparative Example 1) and Zn-0.6Cu-0.2Ca (Example 9) alloys. Furthermore, in the Zn-0.6Cu-xCa (x = 0, 0.2, 0.5 wt%) alloy, most grains exhibit a gradual transition from the initial three colors to intermediate colors. This phenomenon indicates that under the conditions of a rotary forging process with an initial rotary forging speed of 300 r / min, a feed rate of 2 mm / r, and an error within 1 mm, the crystal lattice within the grains undergoes rotation.

[0137] like Figure 5 As shown, the maximum texture intensity of Zn-0.6Cu (Comparative Example 1) is 52.8, the maximum texture intensity of Zn-0.6Cu-0.2Ca (Example 9) is 58.6, and the maximum texture intensity of Zn-0.6Cu-0.5Ca (Example 2) is 6.9. The texture intensity first increases and then decreases with the increase of Ca content.

[0138] 2. Mechanical property testing

[0139] (1) Tensile property test

[0140] Tensile testing at room temperature was performed using an 1NSTRON 5943 electronic universal testing machine according to ASTM E8-2015a standard. Tensile specimens were cut from both the as-cast and forged alloy samples, and gauge lengths were marked. Three specimens of each type were tested, and the average value was taken. After the tensile test, the elongation ΔL of the specimen was measured using vernier calipers. The elongation rate was calculated using the formula A = ΔL / L, and the tensile strength and yield strength of the specimen were recorded.

[0141] (2) Fracture morphology analysis

[0142] The tensile fracture morphology of three forged alloy bars with different Ca contents was analyzed using a JSM-6700 scanning electron microscope to observe the morphology of the tensile fracture surface and thus determine the fracture type of the material.

[0143] (3) Vickers hardness test

[0144] The samples were polished and then surface-etched. The etched samples were then subjected to microhardness testing using a Nanbei HVS-30T Vickers hardness tester. The test force was set to 10 kgf, and the measurement was started and held for 15 seconds. Vickers hardness values ​​were measured at 6 points on each sample, and the average value was taken.

[0145] like Figure 6 As shown, with the addition of Ca, the tensile properties of the zinc-copper alloy Zn-0.6Cu-xCa (x = 0, 0.2, 0.5 wt%) significantly decrease, and the yield strength, tensile strength, and elongation at break of the zinc-copper alloy decrease continuously with increasing Ca content. Figure 7 Numerous equiaxed and loose dimples were observed on the fracture surfaces of all alloys, indicating that the Zn-0.6Cu-xCa (x = 0, 0.2, 0.5 wt%) alloys all underwent ductile fracture during tensile testing. The zinc-copper alloy with 0 Ca content exhibited a denser distribution of dimples, while the proportion of dimples on the fracture surface gradually decreased with increasing Ca content. Figure 8 It is known that the Ca content has a certain influence on the hardness of the alloy material. Among them, Zn-0.6Cu-0.2Ca (Example 9) has the highest hardness, and the hardness of the material decreases with further increase of Ca content. In this regard, the present invention also provides the tensile strength and hardness of Examples 1-13 and Comparative Examples 1-3, as shown in Table 1 below.

[0146] Table 1. Tensile strength and hardness of each sample

[0147]

[0148]

[0149] First, the effect of Ca content on performance: The tensile strength of Comparative Example 1 (Zn-0.6Cu) without Ca was 221 MPa. After adding Ca, the tensile strength of Example 6 (Zn-0.6Cu-0.5Ca) with the same composition dropped to 181 MPa, which verified that "the addition of Ca leads to a decrease in tensile properties".

[0150] At the same Cu content (0.6Cu), as the Ca content increases: Example 11 (0.1Ca, 219MPa) > Example 9 (0.2Ca, 213MPa) > Example 6 (0.5Ca, 181MPa), clearly demonstrating that "the higher the Ca content, the lower the tensile strength".

[0151] At the same Cu content (0.6Cu), as the Ca content increased: Example 11 (0.1Ca, 73HV) < Example 9 (0.2Ca, 75HV) > Example 6 (0.5Ca, 58HV), verifying the trend that "the hardness is highest when Ca = 0.2wt%, and decreases after exceeding this value".

[0152] The hardness of Comparative Example 1 (68 HV) without Ca was lower than that of Example 9 (75 HV) containing 0.2 Ca, but higher than that of Example 6 (58 HV) containing 0.5 Ca, further illustrating that low Ca (0.2 wt%) can improve hardness, while high Ca has the opposite effect.

[0153] Second, the effect of Cu content variation on performance can be obtained through comparison of examples with fixed Ca content:

[0154] With Ca = 0.2 wt%, the strength increases with increasing Cu content: Example 9 (0.6 Cu, 213 MPa) < Example 12 (1 Cu, 222 MPa) < Example 10 (2 Cu, 228 MPa), indicating that increasing Cu content can significantly improve tensile strength.

[0155] When Ca = 0.2 wt%, the hardness increases with increasing Cu content: Example 9 (0.6 Cu, 75 HV) < Example 12 (1 Cu, 76 HV) < Example 10 (2 Cu, 79 HV), indicating that increasing Cu content can improve hardness, which is consistent with the trend of tensile strength.

[0156] Third, under the same composition (Zn-0.6Cu-0.5Ca), the strength of Example 2 (MgB2, 185MPa), Example 4 (Zn-1.0Li, 184MPa), and Example 5 (Zn-2Mg, 182MPa) with the addition of the third component were all higher than that of Example 6 (181MPa) without the addition of the third component, indicating that the third component can slightly alleviate the strength reduction caused by Ca.

[0157] With the same composition (Zn-0.6Cu-0.2Ca), Example 9 with added MgB2 (213MPa) had a higher performance than Comparative Example 3 without the third component (207MPa), further verifying the strengthening effect of the third component.

[0158] With the same composition (Zn-0.6Cu-0.2Ca), Example 9 with added MgB2 (75HV) was higher than Comparative Example 3 without added MgB2 (71HV); Example 7 with added Zn-1.0Li+Zn-0.5Mn (72HV) was also higher than Comparative Example 3, indicating that the third component can improve hardness, and MgB2 is more effective than the composite addition (Zn-1.0Li+Zn-0.5Mn).

[0159] 3. Degradation performance test

[0160] Corrosion immersion tests were conducted according to standard ASTM-G31-2004. Hank's solution was used as a simulated body fluid, and the pH was adjusted to 6.6 with HCl and Tris to simulate the inflammatory environment in the human body. After preparation, the solution was divided into three portions and kept warm in a constant temperature water bath at 36.5±1.5℃.

[0161] Two samples were prepared for each zinc-copper-calcium alloy. The surface was polished using SiC sandpaper up to 2000#, and the polished samples were then shaken and dried. They were then immersed in the corresponding simulated body fluid for 28 days at an experimental temperature of 36.5 ± 0.2℃. The simulated body fluid was changed every 48 hours. One sample was taken out after 3, 7, 14, and 28 days, and the corrosion morphology of the sample surface was analyzed by SEM scanning. The samples were also weighed, and the degradation rate was calculated as (original mass - post-corrosion mass) / original mass × 100% (28 days).

[0162] like Figure 9 As shown, after immersion for 3 days, only a small amount of corrosion products were generated on the surface of the Zn-0.6Cu (Comparative Example 1) sample, while the Zn-0.6Cu-0.2Ca (Example 9) and Zn-0.6Cu-0.5Ca (Example 2) alloys showed a certain degree of corrosion. After immersion for 7 and 14 days, it was clearly observed that the degree of corrosion of each alloy sample increased with time. After immersion for 28 days, all Zn-0.6Cu-xCa (x = 0, 0.2, 0.5 wt%) alloys showed severe corrosion. Throughout the entire immersion period, the Zn-0.6Cu-0.2Ca (Example 9) alloy sample exhibited a uniform corrosion morphology.

[0163] In this regard, the present invention also provides the degradation rates of Examples 1-13 and Comparative Examples 1-3, as shown in Table 2 below.

[0164] Table 2. Degradation rate of each sample

[0165]

[0166]

[0167] The above data shows that, under inflammatory conditions, the degradation rate of the composite third component (such as Li+Mn) is greater than that of the single third component (such as MgB2) and the system without a third component, reflecting the synergistic effect of "third component + remelting" (such as Example 8 > Example 7 > Example 6).

[0168] In an inflammatory environment, the degradation rate was highest at 0.2% Ca (6.1% in Example 9). Degradation rates decreased at levels below 0.1% Ca or too high (2% Ca) (as seen in Examples 11 < 9 < 13 due to excessive Ca).

[0169] The higher the Cu content (2% > 1% > 0.6%), the stronger the inhibition of degradation. Therefore, the degradation rate of Comparative Example 2 (2% Cu) was lower than that of Comparative Example 1 (0.6% Cu), and the degradation rate of Example 10 (2% Cu) was lower than that of Example 9 (0.6% Cu).

[0170] The greater the deformation (drawing > rotary forging > extrusion), the more defects there are, which promotes degradation. Therefore, under the same composition, Example 8 (drawing) > Example 7 (rotary forging) > Example 3 (extrusion).

[0171] The system with remelting (Examples and Comparative Examples 2 and 4) had a higher degradation rate than Comparative Example 3 without remelting due to its uniform composition (the uneven composition led to localized corrosion inhibition).

[0172] 4. Electrochemical Experiment

[0173] Alloy samples with a height of 1 mm and a radius of 4 mm were polished to a bright finish using 1000# to 2000# sandpaper until scratch-free. After cleaning with an ultrasonic cleaner, they were cleaned with anhydrous alcohol and dried. They were then encapsulated with dental plaster and epoxy resin, with an exposed area of ​​0.50 cm² in simulated body fluid. 2 The electrochemical experiment employed a three-electrode system, with the alloy sample serving as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum electrode as the auxiliary electrode. The testing instrument was a ZENNIUM™ 6 electrochemical workstation, and the simulated body fluid used in the experiment was Hanks solution, mimicking the normal human body fluid environment. The open-circuit potential, AC impedance, and polarization curve of the alloy sample in the simulated body fluid were determined using potentiodynamic scanning at a rate of 1 mV / s.

[0174] like Figure 10 As shown, generally speaking, the higher the polarization curve (in the positive potential direction) and the lower the current density, the better the corrosion resistance of the alloy. It can be seen that under normal human environment, the corrosion resistance of Zn-0.6Cu-0.2Ca (Example 9) is better than that of Zn-0.6Cu (Comparative Example 1) and Zn-0.6Cu-0.5Ca (Example 2), indicating that an appropriate amount of Ca can refine the grains and increase the resistance to corrosion reaction; however, when the Ca content is too high, it may form an inhomogeneous phase, and the zinc matrix may become the anode of the corrosion microcell, accelerating local corrosion and causing a change in the potential-current trend.

[0175] The impedance spectrum curve exhibits a semicircle (high-frequency region) and possibly a sloping line (low-frequency region). The larger the diameter of the semicircle, the greater the corresponding charge transfer resistance (reflecting the ease of corrosion reaction), and the better the corrosion resistance. Figure 10 In terms of appearance, Zn-0.6Cu-0.2Ca (Example 9) has an approximately complete and continuous semicircle, and its corrosion resistance is particularly excellent compared to Zn-0.6Cu (Comparative Example 1) and Zn-0.6Cu-0.5Ca (Example 2).

[0176] 5. Antibacterial performance test

[0177] First, liquid culture media for *Escherichia coli* and *Staphylococcus aureus* were prepared. Then, Φ8mm x 1mm forged alloy rod samples were sequentially ground to 2000#, and the finely ground samples were sterilized for later use. The bacterial suspension was diluted to 10 μm with sterile PBS solution. 5 CFU / ml, prepare Zn-0.6Cu-xCa (x=0, 0.2, 0.5wt%) alloy discs and flatten them on the bottom of disposable petri dishes. Add 3ml of diluted bacterial solution to each dish to submerge the sample, and incubate at 37℃ for 24h. Observe the growth of Escherichia coli and Staphylococcus aureus. After incubation, dilute the bacterial solution to one-tenth of its original concentration using sterile PBS solution. Take 10L of the diluted solution and spread it evenly on LB solid medium using the streak plate method. Incubate at 37℃ for 18h, and then photograph with a digital camera.

[0178] Depend on Figure 11 As shown in Table 3, a distinct inhibition zone exists around the Zn-0.6Cu-xCa (x = 0, 0.2, 0.5 wt%) samples, and the radius H of the effective inhibition blank area is between 6.5 and 8 mm. H first increases and then decreases with the increase of Ca addition, indicating that Zn-0.6Cu-0.2Ca (Example 9) has excellent inhibitory performance against Escherichia coli.

[0179] Table 3. Radius of the effective inhibition zone for Escherichia coli

[0180]

[0181] Depend on Figure 12 It can be seen that the Zn-0.6Cu-xCa (x=0, 0.2, 0.5wt%) alloy samples have a large inhibition zone diameter and no bacterial aggregation, indicating that Zn-0.6Cu-xCa (x=0, 0.2, 0.5wt%) all exhibit significant antibacterial ability against Staphylococcus aureus. Table 4 shows that the Zn-0.6Cu-xCa (x=0, 0.2, 0.5wt%) alloys have excellent antibacterial effects against Staphylococcus aureus, with an effective inhibition zone radius H between 10-11.5 mm. Among them, Zn-0.6Cu-0.2Ca (Example 9) showed the best inhibitory performance against Staphylococcus aureus.

[0182] Table 4. Radius of the effective inhibition zone against Staphylococcus aureus

[0183]

[0184]

[0185] IV. Conclusion

[0186] The introduction of calcium alters the microstructure of the Zn-Cu alloy. As the Ca content increases, the content of the second phase within the alloy shows a significant upward trend, and cuboid CaZn phases begin to appear. 13 Solid solution phase. The addition of Ca element changes the grain size of the alloy. For Zn-0.6Cu-0.2Ca (Example 9) and Zn-0.6Cu-0.5Ca (Example 2) alloys, the grains are refined as the Ca element content increases, and the texture strength of the alloy first increases and then decreases.

[0187] The addition of Ca reduces the tensile properties of zinc-copper alloys. In addition, the Ca content has a significant impact on the Vickers hardness of the alloy; among the alloy systems used, the Zn-0.6Cu-0.2Ca alloy (Example 9) achieved the highest hardness value.

[0188] With increasing Ca content, the corrosion degree of the zinc-copper-calcium alloy in simulated body fluids deepens within the same time frame; that is, the corrosion resistance of the Zn-0.6Cu (Comparative Example 1) alloy decreases after adding Ca. Among them, Zn-0.6Cu-0.2Ca (Example 9) exhibits better corrosion uniformity. Furthermore, in a simulated human inflammatory environment, Zn-0.6Cu-0.2Ca (Example 9) shows the highest degradation rate, and in a simulated normal human body fluid environment, Zn-0.6Cu-0.2Ca (Example 9) also demonstrates superior corrosion resistance compared to others. Therefore, Zn-0.6Cu-0.2Ca (Example 9) can solve the problem of difficult-to-control degradation of existing zinc alloys.

[0189] Zn-0.6Cu-xCa alloys with different Ca contents all exhibited good inhibitory effects against Escherichia coli and Staphylococcus aureus, with the alloy material showing better antibacterial effect against Staphylococcus aureus. As the Ca content increased, the antibacterial effect of the alloy first increased and then decreased, with Zn-0.6Cu-0.2Ca (Example 9) showing the best antibacterial performance against both bacteria.

[0190] Based on the above-mentioned mechanical, electrochemical, corrosion, and antibacterial properties, the Zn-0.6Cu-xCa biodegradable zinc alloy has good application prospects in the preparation of bioactive implantable devices and bioactive membranes / patches, especially Zn-0.6Cu-0.2Ca (Example 9). Orthopedic implantable devices include, but are not limited to, bone plates, bone screws, bone tissue repair scaffolds, intramedullary nails, bone sheaths, or spinal fixation devices; bioactive membranes / patches include, but are not limited to, guiding bone regeneration membranes, guiding tissue regeneration membranes, hernia patches, fistula patches, or oral barrier membranes.

[0191] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a biodegradable Zn-Cu-Ca alloy for biomedical use, characterized in that, The Zn-Cu-Ca alloy comprises Zn, Cu, and Ca, wherein the Cu content is 0.6-1.0 wt%, the Ca content is 0.1-0.2 wt%, and the remainder is Zn; the preparation method includes the following steps: (1) Pure Zn spheres, Zn-(2-4)Cu intermediate alloy, and pure calcium particles were selected for batching; (2) Melt the ingredients at a temperature of 500-600℃ to obtain Zn metal melt; (3) Pour the Zn metal melt obtained in step (2) into the prepared mold, and after cooling, obtain Zn-Cu-Ca alloy ingot; (4) Add 0.05-0.5 wt% of the third component X by the alloy mass, and then remelt the Zn-Cu-Ca alloy ingot at a temperature of 430-480℃, stirring to obtain a homogeneous melt. After casting, the melt is rapidly cooled to obtain a Zn-Cu-Ca alloy ingot with uniform composition; wherein, the third component X is at least one of MgB2, Zn-1.0Li, Zn-0.5Mn, Zn-3Mn or Zn-2Mg; (5) The Zn-Cu-Ca alloy ingot is subjected to rotary forging or drawing at a temperature of 100-300℃ to obtain Zn-Cu-Ca alloy profiles.

2. The method for preparing a biomedical biodegradable Zn-Cu-Ca alloy according to claim 1, characterized in that, The Zn-Cu-Ca alloy composition contains 0.6wt% or 1.0wt% Cu and 0.1wt% or 0.2wt% Ca.

3. The method for preparing a biomedical biodegradable Zn-Cu-Ca alloy according to claim 2, characterized in that, In step (3), a graphite mold is selected, the pouring temperature is controlled at 180-230℃, and low-temperature casting or semi-solid casting is adopted.

4. The method for preparing a biomedical biodegradable Zn-Cu-Ca alloy according to claim 1, characterized in that, In step (4), first use sandpaper or grinding wheel to polish and remove the oxidation and dirt on the surface of the Zn-Cu-Ca alloy ingot, and then remelt it in the furnace.

5. The method for preparing a biomedical biodegradable Zn-Cu-Ca alloy according to claim 1, characterized in that, Zn-Cu-Ca alloy profiles include bars, plates, and foils.

6. A biodegradable Zn-Cu-Ca alloy for biomedical use, characterized in that, It is prepared by the method described in any one of claims 1-5 for preparing biomedical biodegradable Zn-Cu-Ca alloy.

7. The application of the biodegradable Zn-Cu-Ca alloy as described in claim 6 in the preparation of bioactive implantable devices, including its application in the preparation of orthopedic implantable devices and bioactive membranes / patches.

8. The application according to claim 7, characterized in that, The orthopedic implants include at least one of bone plates, bone screws, bone tissue repair scaffolds, intramedullary nails, bone sheaths, or spinal fixation devices; the bioactive membranes include at least one of guiding bone regeneration membranes, guiding tissue regeneration membranes, or oral barrier membranes; and the bioactive patches include at least one of hernia patches or fistula patches.

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