Preparation method of degradable zinc alloy material

Abstract

The application discloses a preparation method of a degradable zinc alloy material, and belongs to the technical field of biological metal materials. The preparation method comprises the following steps: melting and heat-insulating zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks; then pouring into a casting mold and directly solidifying; and finally rolling in multiple passes. The chemical composition and content of the degradable zinc alloy material are as follows: 0.05-2wt% of Mg, 1-3wt% of Ag, 0.1-0.4% of Ti, and the balance of Zn. The application can control the types, quantities and distributions of intermetallic compounds Mg2Zn 11 , TiZn 16 phases and elemental Ag by regulating alloy components, contents and preparation methods, so that the zinc-based alloy with good mechanical properties, a suitable biodegradation rate and good antibacterial performance can be prepared and can be used for manufacturing different biological medical materials, such as vascular stents, orthopedic implants and surgical sutures.

Description

Technical Field

[0001] This invention belongs to the field of biometallic materials technology, specifically relating to a method for preparing a biodegradable zinc alloy material. Background Technology

[0002] Biodegradable materials generally refer to functional materials used in the diagnosis and repair of tissues or organs for disease treatment, which do not produce side effects on tissues, organs, and blood. They are classified according to their biochemical reactivity in the physiological environment into inert biomaterials, active biomaterials, and biodegradable biomaterials. Inert biomaterials possess good mechanical properties, low elastic modulus, ease of processing, corrosion resistance, and biocompatibility; however, their implants only have a simple mechanical bond with surrounding tissues and cannot form excellent bonds. Over time, this can easily lead to thrombosis and implant failure. Active biomaterials are materials that can form specific biological reactions on their surface, allowing tissues to form chemical bonds with them; however, their mechanical strength decreases significantly with long-term use. The effects of non-biodegradable materials may accompany patients throughout their lives, causing not only long-term pain but also inconvenience in daily life and work, potentially inducing various rejection reactions and leading to serious consequences. With the rapid development of medical tissue engineering and materials science, biodegradable materials have received increasing attention in recent years due to their "degradable" capabilities.

[0003] However, the excessively rapid degradation rate of magnesium alloys can severely affect the mechanical integrity of implants, and the degradation process of magnesium can generate bubbles. Iron alloys, on the other hand, degrade too slowly, and the long-term presence of corrosion products in the body can lead to complications. In comparison, zinc alloys have been shown to have a suitable corrosion rate and good mechanical integrity, making them promising candidates for use in medical devices. The standard electrode potential of Zn is -0.76V, falling between that of Mg (-2.37V) and Fe (-0.44V), thus providing a suitable corrosion rate for implant materials.

[0004] CN112080655A discloses a microalloyed medical antibacterial Zn-Mg-Ag alloy and its preparation method. The alloy is obtained through initial melting, followed by investment casting and multi-pass extrusion deformation. This invention, by adding trace amounts of Mg and Ag elements to pure Zn, not only reduces the cost of alloy design, but also achieves a yield strength of 130–250 MPa, a tensile strength of 150–285 MPa, an elongation of 2–7%, and an antibacterial rate of 42–80% against Staphylococcus aureus. The alloy also exhibits a suitable degradation rate and good biocompatibility.

[0005] CN105986146A discloses an invention relating to a biodegradable zinc-based alloy for biomedical use. The alloy is characterized by a zinc alloy system composed of Zn, Mg, Ca, and Mn, with the following mass percentages: Mg 0–1.5%, not 0%; Ca 0–0.5%; Mn 0–0.2%, with the balance being Zn. The zinc-based alloy prepared by this invention avoids the introduction of undesirable elements, possesses excellent mechanical properties, superior corrosion resistance, and strong controllability of corrosion failure, thus meeting the requirements of the medical device field for the biosafety and comprehensive mechanical properties of biomaterials.

[0006] CN111529761A discloses a biodegradable Zn-Ti binary biomedical material and its preparation method. The Zn-Ti binary biomedical material comprises the following components by mass percentage: Ti 0.01-2.5 wt%, with the balance being Zn, to provide a biodegradable Zn-Ti binary biomedical material and its preparation method with higher mechanical properties and better cell compatibility.

[0007] CN105925847B discloses a biodegradable zinc-based metal material and a formulation for preparing a ureteral dilatation stent using this material. The zinc-based metal material is composed of zinc and / or a zinc alloy, wherein the zinc alloy is an alloy of Zn with one or more of the following elements: Mg, Al, Ti, Cu, Ag, Si, Ca, Sr, Y, Zr, Sc, Gd, Nd, Dy, Er, Li, Mn, La, Ce, Pr, Sm, Tb, Ho, Tm, Yb, and Lu. This biodegradable zinc-based metal material exhibits good biocompatibility, biodegradability, and mechanical properties, and has broad market application prospects. However, the disclosed elements are numerous, and the elemental ratios fluctuate significantly. The influence of intermediate components formed between various elements on the material is not explained, and the preparation process of the material is lacking.

[0008] Currently published biodegradable zinc-based alloys primarily improve mechanical and corrosion resistance by adding trace alloying elements harmless to humans, such as Ti, Ca, Mn, and Ag. These elements, during manufacturing, react with the Zn matrix to form small, dispersed precipitates in situ, acting as nucleation sites for heterogeneous growth and refining the grain size. However, the number of precipitates in the manufacturing process of these published biodegradable alloys is somewhat limited. Summary of the Invention

[0009] To address the shortcomings of the prior art, this invention provides a method for preparing a biodegradable zinc alloy material.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a biodegradable zinc alloy material, which achieves optimal performance of the zinc alloy by adjusting its chemical composition and preparation method; includes the following steps:

[0012] S1: Add zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks in sequence for smelting, and then keep warm to obtain a completely molten liquid;

[0013] S2: Pour the completely molten liquid into a casting mold and solidify to obtain the Zn-Mg-Ag-Ti alloy;

[0014] S3: A biodegradable zinc alloy material is obtained by rolling a Zn-Mg-Ag-Ti alloy in multiple passes on a rolling mill;

[0015] The chemical composition and mass percentage of the biodegradable zinc alloy material are: 0.05-2 wt% Mg, 1-3 wt% Ag, 0.1-0.4% Ti, with the balance being Zn.

[0016] In a preferred embodiment of the present invention, in step S1, considering the loss of alloy during the smelting process, the mass percentage of zinc blocks in the mixture of zinc blocks, ZnMg50 metal blocks, Ag metal blocks, and Ti metal blocks is 10-15% higher than the mass percentage of Zn in the biodegradable zinc alloy material. The mass percentages of Mg and Ag in the mixture of zinc blocks, ZnMg50 metal blocks, Ag metal blocks, and Ti metal blocks are 7-15% higher than the mass percentages of Mg and Ag in the biodegradable zinc alloy material, respectively. The mass percentage of Ti in the mixture of zinc blocks, ZnMg50 metal blocks, Ag metal blocks, and Ti metal blocks is 2-5% higher than the mass percentage of Ti in the biodegradable zinc alloy material, respectively.

[0017] In a preferred embodiment of the present invention, the heat preservation time in S1 is 10 minutes.

[0018] In a preferred embodiment of the present invention, in step S2, the fully molten Zn+Mg+Ag+Ti melt is poured into a casting mold at a temperature of 200°C to 400°C.

[0019] In a preferred embodiment of the present invention, the rolling temperature is 300℃~400℃, the single rolling is 0.5mm, and the material needs to be kept warm during the rolling process.

[0020] As a preferred embodiment of the present invention, in step (1), the melting container and casting mold are cleaned and preheated before melting.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adds Mg, Ag, and Ti to Zn alloys, and controls the intermetallic compound Mg2Zn by adjusting the alloy composition, content, and preparation method.11 TiZn 16 By studying the types, quantities, and distribution of phases and elemental Ag, zinc-based alloys with good mechanical properties, suitable biodegradation rates, and good antibacterial properties can be prepared, which can be used to manufacture various biomedical materials, such as vascular stents, orthopedic implants, and surgical sutures. Attached Figure Description

[0022] Figure 1 This is an image showing the appearance of the sample prepared in Example 1.

[0023] Figure 2 This is a microscopic morphology image of the sample prepared in Example 1.

[0024] Figure 3 The image shows the microstructure of the sample prepared in Comparative Example 1.

[0025] Figure 4 The images show the XRD patterns of the samples prepared in Examples 2-9.

[0026] Figure 5 The following are polarization curves for comparative examples 1-5.

[0027] Figure 6 This is a Nyquistplot of Comparative Examples 1-5. Detailed Implementation

[0028] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] Example 1:

[0030] A method for preparing a biodegradable Zn-Mg-Ag-Ti alloy, wherein the raw materials are prepared by mixing four alloying elements—zinc, magnesium, silver, and titanium—in a designed mass percentage, wherein the Mg content is 2%, the Ag content is 3%, the Ti content is 0.4%, and the balance is Zn; the zinc block is 99.99%, and the ZnMg alloy is... 50 The purity is 99.99%, Ag is 99.9%, and Ti is 99.99%.

[0031] The specific steps are as follows:

[0032] S1: Clean and preheat the crucible and mold. This helps to reduce the solidification rate of the alloy and reduce casting defects.

[0033] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks are added in sequence and kept at a temperature for 10 minutes to obtain a completely molten Zn+Mg+Ag+Ti melt.

[0034] S3: The fully molten Zn+Mg+Ag+Ti molten liquid is poured into a casting mold at a temperature of 400℃ until the mold is full, and the metal solution is completely solidified to obtain a Zn-2%Mg-3%Ag-0.4%Ti alloy.

[0035] S4: The alloy is rolled in multiple passes on a rolling mill at a temperature of 300℃, with a single roll thickness of 0.5 mm. The material needs to be continuously kept at this temperature during the rolling process. The macroscopic morphology after rolling is shown in the image below. Figure 1 As shown, the microstructure diagram is as follows: Figure 2 As shown in the figure, the comparison revealed that rolling can reduce the grain size of intermetallic compounds.

[0036] Example 2:

[0037] A method for preparing a biodegradable zinc alloy material, wherein the raw materials are formulated from four alloying elements, zinc, magnesium, silver, and titanium, according to a designed mass percentage, wherein the content of Mg is 0.05%, the content of Ag is 1%, the content of Ti is 0.1%, and the balance is Zn; the zinc block is 99.99%, ZnMg50 is 99.99%, Ag is 99.9%, and Ti is 99.99%.

[0038] The specific steps are as follows:

[0039] S1: Clean and preheat the crucible and mold. This helps to reduce the solidification rate of the alloy and reduce casting defects.

[0040] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks are added in sequence and kept at the temperature for 10 minutes to obtain a completely molten Zn+Mg+Ag+Ti melt.

[0041] S3: The fully molten Zn+Mg+Ag+Ti melt is poured into a casting mold at 200℃ until the mold is full, and the metal solution is completely solidified to obtain a Zn-0.05%Mg-1%Ag-0.1%Ti alloy.

[0042] S4: The alloy is rolled in multiple passes on a rolling mill at a temperature of 300℃, with a single roll thickness of 0.5mm. The material needs to be kept warm during the rolling process.

[0043] Example 3:

[0044] The difference between this embodiment and Embodiment 2 is that the Ti content is 0.2%.

[0045] Example 4:

[0046] The difference between this embodiment and Embodiment 2 is that the Ti content is 0.3%.

[0047] Example 5:

[0048] The difference between this embodiment and Example 2 is that the Mg content is 0.25%.

[0049] Example 6:

[0050] The difference between this embodiment and Example 2 is that the Mg content is 0.25%.

[0051] Example 7:

[0052] The difference between this embodiment and Example 3 is that the Mg content is 0.25%.

[0053] Example 8:

[0054] The difference between this embodiment and Example 4 is that the Mg content is 0.25%.

[0055] Example 9:

[0056] The difference between this embodiment and Example 5 is that the Mg content is 0.25%.

[0057] Comparative Example 1:

[0058] The difference between this comparative example and Example 1 is that the solidified Zn-2%Mg-3%Ag-0.4%Ti alloy was not subjected to rolling treatment.

[0059] The morphology of the alloy prepared in Example 1 after rolling is shown in Figures (1) and (2), and the microstructure of the unrolled alloy is shown in Figure 1. Figure 3 As shown, compared with Example 1, the grain refinement of the alloy material after rolling in Example 1 is obvious.

[0060] Comparative Example 2:

[0061] A method for preparing a biodegradable zinc alloy material, wherein the raw materials are prepared by mixing zinc, magnesium and silver alloying elements according to a designed mass percentage, wherein the Mg content is 0.05%, the Ag content is 1%, and the balance is Zn; the zinc block is 99.99%, ZnMg50 is 99.99%, and Ag is 99.9%.

[0062] The specific steps are as follows:

[0063] S1: Clean and preheat the crucible and mold. This helps to reduce the solidification rate of the alloy and reduce casting defects.

[0064] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, ZnMg50 metal blocks and Ag metal blocks are added in sequence and kept at a temperature for 10 minutes to obtain a completely molten Zn+Mg+Ag liquid.

[0065] S3: The fully molten Zn+Mg+Ag liquid is poured into a casting mold at 300℃ until the mold is full, and the metal solution is completely solidified to obtain a Zn-0.05%Mg-1%Ag alloy.

[0066] S4: The alloy is rolled in multiple passes on a rolling mill at a temperature of 300℃, with a single roll thickness of 0.5 mm. The material requires continuous heat treatment during the rolling process, and a small amount of Mg2Zn is observed. 11 Ag exists in the form of an element.

[0067] Comparative Example 3

[0068] A method for preparing a biodegradable zinc alloy material, wherein the raw materials are formulated from zinc, magnesium, and titanium alloying elements according to a designed mass percentage, wherein the Mg content is 0.05%, the Ti content is 0.1%, and the balance is Zn; the zinc block is 99.99%, and the ZnMg content is... 50 The purity is 99.99%, and the purity of Ti is 99.99%.

[0069] The specific steps are as follows:

[0070] S1: Cleaning and preheating the crucible and mold helps to reduce the solidification rate of the alloy and reduce casting defects.

[0071] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, ZnMg50 metal blocks and Ti metal blocks are added in sequence and kept at a temperature for 10 minutes to obtain a completely molten Zn+Mg+Ti melt.

[0072] S3: The fully molten Zn+Mg+Ti molten liquid is poured into a casting mold at a temperature of 200℃ until the mold is full, and the metal solution is completely solidified to obtain a Zn-0.05%Mg-0.1%Ti alloy.

[0073] S4: The alloy is rolled in multiple passes on a rolling mill at a temperature of 300℃, with a single roll thickness of 0.5mm. The material needs to be kept warm during the rolling process.

[0074] Comparative Example 4

[0075] A method for preparing a biodegradable zinc alloy material, wherein the raw materials are prepared by mixing zinc, silver and titanium in a designed mass percentage, wherein the content of Ag is 1%, the content of Ti is 0.1%, and the balance is Zn; the zinc block is 99.99%, the content of Ag is 99.9%, and the content of Ti is 99.99%.

[0076] The specific steps are as follows:

[0077] S1: Cleaning and preheating the crucible and mold helps to reduce the solidification rate of the alloy and reduce casting defects.

[0078] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, Ag metal blocks, and titanium metal blocks are added in sequence and kept at a temperature for 10 minutes to obtain a completely molten Zn+Ag+Ti melt.

[0079] S3: The fully molten Zn+Ag+Ti molten liquid is poured into a casting mold at a temperature of 200℃ until the mold is full, and the metal solution is completely solidified to obtain the Zn-1%Ag-0.1%Ti alloy.

[0080] S4: The alloy is rolled in multiple passes on a rolling mill at a temperature of 300℃, with a single roll thickness of 0.5mm. The material needs to be kept warm during the rolling process.

[0081] Comparative Example 5

[0082] A method for preparing a biodegradable zinc alloy material, wherein the raw materials are formulated from four alloying elements—zinc, magnesium, silver, and titanium—according to a designed mass percentage, wherein the content of Mg is 2%, the content of Ag is 3%, the content of Ti is 0.4%, and the balance is Zn; the zinc block is 99.99%, and the ZnMg content is... 50 The purity is 99.99%, Ag is 99.9%, and Ti is 99.99%.

[0083] The specific steps are as follows:

[0084] S1: Cleaning and preheating the crucible and mold helps to reduce the solidification rate of the alloy and reduce casting defects.

[0085] S2: The material is smelted using a medium-frequency induction rate. Zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks are added in sequence and kept at a temperature for 10 minutes to obtain a completely molten Zn+Mg+Ag+Ti melt.

[0086] S3: The fully molten Zn+Mg+Ag+Ti molten liquid is poured into a casting mold at a temperature of 400℃ until the mold is full, and the metal solution is completely solidified to obtain a Zn-2%Mg-3%Ag-0.4%Ti alloy.

[0087] S4: The alloy is subjected to multi-pass extrusion hot deformation. The Zn-2%Mg-3%Ag-0.4%Ti alloy at 200℃ is placed in the extrusion die and pressurized. The pressure is adjusted to 300MPa, the extrusion ratio is 36:1, and the extrusion speed is 3mm / s. During pressurization, the extrusion die is continuously heated by medium frequency at a temperature of 400℃. The pressure is maintained, the medium frequency heating is turned off, and the extrusion die is continuously subjected to a pressure of 300MPa for 40-60 seconds to obtain a biodegradable zinc alloy material.

[0088] Example 1

[0089] The alloys prepared in the examples and comparative examples were cut using a wire EDM machine, polished with 400-2000 grit sandpaper, and then subjected to electrochemical experiments. The electrochemical experiments were conducted under sterile conditions at a constant temperature of 37°C. The average corrosion rate of the materials, fitted by Tafel curves, was 0.023 mm / year. AC impedance analysis revealed two types of corrosion: double-layer corrosion and metallic corrosion. Polarization curves are shown below. Figure 5 The Nyquist plot of AC impedance is shown in [reference needed]. Figure 6 Electrochemical experiments revealed that the corrosion type and rate of degradable zinc alloy materials can be controlled by adjusting the quantity and distribution of the intermediate phase. A comparison of the corrosion performance of the alloys is shown in Table 1.

[0090] Table 1

[0091]

[0092] pass Figure 2 and Figure 3 The comparison revealed that the size of the mesophase was significantly reduced after rolling, and the number of distributed mesophase phases was also significantly reduced. According to Examples 2-9 in Table 1, with the increase of a small amount of Ti, the corrosion rate first decreased and then increased, and the corrosion tendency also first decreased and then increased. The corrosion rate after fitting the electrochemical corrosion polarization curve first decreased and then increased, with the lowest corrosion rate observed when the Ti content was between 0.2% and 0.3%. This is consistent with the TiZn... 16 The formation of Mg2Zn is related to the eutectic points of the Ti-Zn phase diagram. With increasing Mg content, Mg2Zn... 11 Similarly, the average corrosion tendency also increases, according to Figure 4 As shown, a small amount of Mg2Zn is distributed in the alloy material. 11 and TiZn 16 Ag exists in the form of an element.

[0093] Compared with Comparative Examples 2-4, Example 2 showed a reduced corrosion tendency and corrosion rate due to the lack of elemental Ag phase formation in Comparative Example 3. Compared with Comparative Example 4, Example 2 showed a reduced corrosion tendency and corrosion rate because Comparative Example 4 lacked the intermediate phase Mg₂Zn. 11 The corrosion rate increases. The alloy described in this invention contains elemental Ag phase and Mg2Zn... 11 and TiZn 16 The intermediate phases work together to form an electric double layer that protects the alloy and reduces the corrosion rate. Therefore, in Comparative Examples 2-4, the absence of any one of the elements in the intermediate phase will lead to an increase in the corrosion current and corrosion rate of the alloy.

[0094] As can be seen from Example 1 and Comparative Example 5, the combination of preparation method and composition can enhance corrosion resistance. In Example 1, the preparation method results in a smaller intermediate phase transformation and a more uniform distribution of the material, which improves the corrosion performance of the material.

[0095] Example 2

[0096] The alloys prepared in the examples and comparative examples were cut by wire cutting machine according to ASTM-E8-04Z standard. After cutting, they were pickled, alkali washed and ultrasonically cleaned, polished with 2000 grit sandpaper, and tested under a universal testing machine. The tensile data are shown in Table 2.

[0097] Table 2

[0098]

[0099]

[0100] As shown in Example 1 and Comparative Example 1, the amount and size of the mesophase are reduced after rolling. The mesophase can increase the strength of the material, but it also reduces the elongation. Comparing Example 2 and Comparative Examples 2-4, Ag and TiZn... 16 Increasing the elongation of the material and Mg2Zn 11 The increase of these three elements can improve strength. All three are distributed at the grain boundaries of the intermediate phase, which can strengthen the grain boundaries and form more dislocations.

[0101] As can be seen from Example 1 and Comparative Example 5, the combination of preparation method and composition is necessary to enhance corrosion resistance. In Comparative Example 5, the preparation method results in a smaller and more uniform intermediate phase transformation in the material, which further improves the corrosion resistance and mechanical properties of the material.

[0102] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing a biodegradable zinc alloy material, characterized in that, Optimal performance of zinc alloy materials is achieved by adjusting the chemical composition and preparation method of zinc alloys; this includes the following steps: S1: Add zinc blocks, ZnMg50 metal blocks, Ag metal blocks and Ti metal blocks in sequence for smelting, and then keep warm to obtain a completely molten liquid; S2: Pour the fully molten liquid into a casting mold and solidify to obtain a Zn-Mg-Ag-Ti alloy; in S2, the fully molten liquid is poured into the casting mold at a temperature of 200℃~400℃. S3: A biodegradable zinc alloy material is obtained by rolling a Zn-Mg-Ag-Ti alloy in multiple passes on a rolling mill; the chemical composition and mass percentage of the biodegradable zinc alloy material are: 0.05-2 wt% Mg, 1-3 wt% Ag, 0.1-0.4% Ti, with the balance being Zn; the rolling temperature is 300℃-400℃, the single rolling thickness is 0.5 mm, and the material is continuously kept at a high temperature during the rolling process.

2. The method for preparing the biodegradable zinc alloy material as described in claim 1, characterized in that, In S1, the heat preservation time is 10 minutes.

3. The method for preparing the biodegradable zinc alloy material as described in claim 1, characterized in that, In step (1), the melting container and casting mold are cleaned and preheated before melting.

Images