Biodegradable low-silicon iron manganese alloy material as well as preparation method and application thereof

Abstract

The invention relates to a biodegradable low-silicon iron-manganese alloy material and a preparation method and application thereof.Si and N in Fe-Mn-Si-N alloy are cooperatively adjusted, so that the elasticity modulus and ductility of Fe-Mn-Zn-Si are effectively improved on the basis that Fe-Mn-Si-N meets the CT / MRI imaging requirement, the strength meets the requirement, and the mechanical property of Fe-Mn-Zn-Si alloy is improved. Further, the elasticity, the compression release effect and the shape memory effect of the stent prepared from the Fe-Mn-Zn-Si alloy are improved; according to the method, Si and N in the Fe-Mn-Si-N alloy are cooperatively adjusted, so that the polarization current density is increased, the corrosion driving force of the Fe-Mn-Si-N alloy is remarkably improved, the degradation rate of the Fe-Mn-Si-N alloy is greatly increased, and controllable degradation is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of degradable implantable medical devices, and particularly relates to a biodegradable low-silicon iron-manganese alloy material and a preparation method and application thereof. BACKGROUND

[0002] Portal hypertension is a clinical syndrome caused by the pathological and persistent increase of the portal pressure gradient, which is often seen in patients with advanced liver disease, and can also be seen in patients with hepatic sinusoidal syndrome and portal vein thrombosis. The clinical manifestations include abdominal distension, collateral blood vessel varicosity, ascites, and gastrointestinal bleeding. If effective treatment measures are not taken in time, the quality of life of the patient will decrease dramatically, and even death can occur due to gastrointestinal varicose bleeding. Transjugular intrahepatic portosystem stent-shunt (TIPS) is a method for effectively and rapidly reducing portal hypertension. By using a stent to establish a shunt channel between the portal vein system and the vena cava system through a minimally invasive interventional method, the portal pressure is significantly reduced, which is beneficial to the improvement of liver function and symptoms, significantly improves the quality of life of the patient, prolongs the survival time of the patient, and gains time for the treatment of liver disease.

[0003] The existing biodegradable ternary iron-manganese alloy material Fe Mn Si is used to prepare a shape memory alloy (SMAs) for a TIPS stent, which has the advantages of low cost, fast degradation rate, good mechanical properties, excellent processing performance, high corrosion resistance, and the like, and is concerned. In the Fe-Mn-Si ternary iron-manganese alloy system, Mn is one of the important elements affecting the performance of the alloy. First, the Mn content in the range of 20wt%-35wt% makes the alloy system produce diamagnetism, which makes pure Fe change from ferromagnetic to non-ferromagnetic, so that the Fe-Mn-Si alloy has good MRI imaging properties. Second, Mn is a nutrient substance necessary for bone formation, lipid, amino acid and carbohydrate metabolism, and has biological safety. However, when the content of Mn is too high, banded structure will appear in the alloy, which reduces the strength of the alloy. At the same time, the increase of the concentration of Mn atoms at the grain boundary will reduce the intergranular binding force in the alloy, thereby reducing the impact toughness of the alloy and causing a brittle tendency. This results in a physical contradiction that it is difficult to meet the above requirements after the content of Mn in the Fe-Mn-Si alloy system is determined, that is, the content of Mn in the Fe-Mn-Si alloy system must be high enough to meet the concentration requirement of producing diamagnetism, and the content of Mn must not be too high to meet the requirement of not reducing the strength and impact toughness of the alloy.

[0004] Meanwhile, in the Fe-Mn-Si ternary iron-manganese alloy system, Si is also one of the important elements affecting the performance of the alloy. On the one hand, Si can reduce the Neel transition temperature of the Fe-Mn-Si alloy; on the other hand, Si can adjust the segregation of Mn in the alloy, inhibit the magnetic phase transition caused by excessive Mn content, increase the generation amount of stress-induced martensite, improve the reversibility of the martensite phase transition, and at the same time, Si can help to inhibit the dislocation sliding and promote the generation of stacking faults in the alloy, form solid solution strengthening, improve the yield strength of the alloy and reduce the proportion of plastic deformation, so that the alloy obtains shape memory effect and improves the shape memory performance of the Fe-Mn-Si-based shape memory alloy. However, when the Si content exceeds 6 wt%, high Si superimposed high Mn will make the Fe-Mn-Si-based shape memory alloy brittle. SUMMARY

[0005] The purpose of the present application is to provide a biodegradable low-silicon iron-manganese alloy material, which is sufficient to meet the magnetic resistance requirements of the iron-manganese alloy based on the Mn content, and solves the problems of reduced strength, reduced impact toughness and easy brittleness of the Fe Mn Si alloy caused by excessive Mn content.

[0006] The biodegradable low-silicon iron-manganese alloy material provided by the present application comprises: The mass percentage of Mn is 20% to 30%; The mass percentage of Si is 1% to 2%; The mass percentage of N is 0.05% to 0.1%, and the balance is Fe.

[0007] Compared with the prior art, the biodegradable low-silicon iron-manganese alloy material provided by the present application introduces N into the Fe Mn Si ternary system and keeps the Si content at a low level, so that the Fe Mn Si alloy with shape memory can meet the requirements of controllable corrosion rate and good MRI imaging, improve the strength and impact toughness of the Fe Mn Si alloy, and avoid the brittleness of the Fe Mn Si alloy. N is a biocompatible element, which can improve the strength of the Fe-Mn-Si alloy through solid solution strengthening, and improve the toughness of the alloy by inhibiting the grain boundary segregation of Mn, thereby balancing the brittleness tendency caused by excessive Mn content; at the same time, the interstitial atom characteristics of N can refine the grains and reduce the electrode potential difference of the Fe-Mn-Si alloy, and the micro electrochemical corrosion unit formed by N and the matrix Fe can promote the controllable degradation process. Low content of Si (1 wt% to 2 wt%) can avoid the brittleness of the Fe-Mn-Si alloy on the basis of improving the yield strength of the Fe-Mn-Si alloy, and can synergistically adjust and inhibit the grain boundary segregation of high content of Mn, improve the toughness and reversibility of the shape memory effect of the Fe-Mn-Si alloy, and synergistically control the mechanical properties, phase transition characteristics and degradation rate of the alloy.

[0008] Further, C is further included, and the mass percentage of the C is 0.05% to 0.1%. The introduction of the C can further improve the hardness and yield strength of the Fe-Mn-Si-N alloy, hinders dislocation slip by forming nanoscale carbides, increases the generation efficiency of stress-induced martensite, and meanwhile, the potential difference between the carbides and the matrix can regulate the degradation kinetics, forms a uniform corrosion mode, and has better degradation effect.

[0009] Further, Ti is further included, and the mass percentage of the Ti is 0.05% to 0.1%. As a strong carbide forming element, the Ti can form stable intermetallic compounds with Fe, improve the corrosion resistance and high-temperature stability of the alloy, further enhance the reversibility of the shape memory effect by inhibiting the dislocation movement in the process of the reverse phase transformation of the martensite, and meanwhile, can optimize the interface matching degree of the austenite and the martensite two phases, improve the phase change driving force, make the synergistic regulation ability of the combined addition of N, C and Ti stronger, and make the mechanical properties, phase change characteristics and degradation rate of the Fe-Mn-Si-N-C-Ti alloy better.

[0010] Meanwhile, the application provides a preparation method of the biodegradable low-silicon iron-manganese alloy material. S10 melts the raw materials pure iron, electrolytic Mn, MnN and Si into a block-shaped alloy, wherein the mass percentage of the electrolytic Mn and MnN is 20wt% to 30wt% in total, the mass percentage of the Si is 1wt% to 2wt%, the mass percentage of the N is 0.05wt% to 0.1wt%, and the balance is Fe.

[0011] S20 uniformly anneals the block-shaped alloy at a set annealing temperature, annealing time and vacuum environment to obtain the Fe-Mn-Si-N alloy.

[0012] Compared with the prior art, the preparation method of the biodegradable low-silicon iron-manganese alloy material provided by the application has the advantages of simple preparation method, and the prepared biodegradable low-silicon iron-manganese alloy material has the same beneficial effects as the biodegradable low-silicon iron-manganese alloy material described above, which will not be repeated here.

[0013] Further, the raw materials for melting in step S10 further include C or C and Ti, wherein the mass percentage of the C is 0.05wt% to 0.1wt%, and the mass percentage of the Ti is 0.05wt% to 0.1wt%.

[0014] Further, the purity of the raw materials for melting in step S10, pure iron, electrolytic Mn, MnN, Si, C and Ti, is all greater than or equal to 99.9%.

[0015] Further, the annealing temperature is set to 1000°C to 1100°C, the annealing time is set to 5 hours to 7 hours, and the vacuum degree in the vacuum environment is 10-3 ~10 -5 Pa.

[0016] Meanwhile, this invention provides an application of a biodegradable low-silicon iron-manganese alloy material for preparing a biodegradable TIPS scaffold with controllable corrosion rate, comprising the following preparation steps: S30 The biodegradable low-silicon iron-manganese alloy material described in any of the above items is drawn into wire to obtain FeMn Si-N alloy wire. S40 involves braiding Fe Mn Si-N alloy wires using a structural braiding pattern with sine curves as the basic unit to obtain a self-expanding Fe Mn Si-N alloy bare scaffold. S50 uses a coating material to coat the self-expanding FeMnSi-N alloy bare scaffold.

[0017] Compared with the prior art, the biodegradable TIPS scaffold with controllable corrosion rate prepared by the above-mentioned biodegradable low silicon iron manganese alloy material provided by the present invention can be degraded in vivo without toxic side effects; and the scaffold has good elasticity, shape memory effect and compression release effect.

[0018] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the preparation method of the biodegradable low-silicon iron-manganese alloy material of the present invention; Figure 2 This is a schematic diagram illustrating the application process of the biodegradable low-silicon iron-manganese alloy material of the present invention. Figure 3 A schematic diagram of a self-expanding bare biliary stent prepared according to an embodiment of the present invention; Figure 4 for Figure 3 Schematic diagram of the coating process; Figure 5 This is a schematic diagram of a self-expanding bare vascular stent graft prepared according to one embodiment of the present invention; Figure 6 These are constant voltage polarization curves of Examples 1-6 and Comparative Examples 1-3 of the present invention; Figure 7 These are open-circuit potential curves for Embodiments 1-6 and Comparative Examples 1-3 of the present invention; Figure 8 This is a comparison image of the corrosion process before and after in Example 1 of the present invention; Figure 9 This is a comparison image of the corrosion process before and after in Example 2 of the present invention; Figure 10 This is a comparison image of the corrosion process before and after in Example 3 of the present invention; Figure 11 This is a comparison image of the corrosion process before and after in Example 4 of the present invention; Figure 12 This is a comparison image of the corrosion process before and after in Example 5 of the present invention; Figure 13 This is a comparison image of the corrosion process before and after in Example 6 of the present invention; Figure 14 This is a comparison image of Comparative Example 1 of the present invention before and after corrosion; Figure 15 This is a comparison image of Comparative Example 2 of the present invention before and after corrosion; Figure 16 This is a comparison image of Comparative Example 3 of the present invention before and after corrosion. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more comprehensive and detailed description of the present invention will be provided below, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0021] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0022] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention are well known in the art, but do not limit the implementation of this invention. Other reagents and equipment well known in the art can also be applied to the implementation of the following embodiments of this invention.

[0023] To address the issues of reduced strength and decreased toughness in existing high-manganese-content biodegradable shape memory alloys Fe-Mn-Si while maintaining imaging compatibility in medical imaging examinations, this invention proposes a biodegradable low-silicon iron-manganese alloy material. By introducing N into the Fe-Mn-Si alloy and reducing the Si content, the shape memory Fe-Mn-Si alloy can improve its strength and impact toughness while maintaining controllable corrosion rate and good MRI imaging properties, and prevent the Fe-Mn-Si alloy from becoming embrittled.

[0024] Please see Figure 1 The following details the preparation method of the biodegradable low-silicon iron-manganese alloy material of this application, including the following steps.

[0025] S10 is made by melting raw materials pure iron, electrolytic Mn, MnN, and Si into a block alloy.

[0026] In practice, a high-frequency electromagnetic induction melting furnace or an electric arc induction melting furnace is used to melt pure iron, electrolytic Mn, MnN, and Si. The high-frequency electromagnetic induction melting furnace or the electric arc induction melting furnace rapidly melts the above raw materials using a high-power current, reducing the volatilization of Mn. Specifically, the electrolytic Mn and MnN have a combined Mn mass percentage of 20%~30%, Si a mass percentage of 1%~2%, and N a mass percentage of 0.05%~0.1%.

[0027] In some embodiments, the raw materials smelted in step S10 further include C, or C and Ti, wherein the mass percentage of C is 0.05% to 0.1% and the mass percentage of Ti is 0.05% to 0.1%.

[0028] In some embodiments, the purity of the raw materials smelted in step S10, including pure iron, electrolytic Mn, MnN, Si, C, and Ti, is ≥99.9%.

[0029] S20 involves homogenizing the bulk alloy under a set annealing temperature, annealing time, and vacuum environment to obtain the FeMnSi-N alloy.

[0030] In practice, the annealing temperature is set to 1000℃~1100℃, and the annealing time is set to 5 hours~7 hours. The annealing is performed under vacuum conditions with a vacuum level of 10⁻³~10⁻⁵ Pa. Homogenization annealing can make the FeMnSi-N alloy have a uniform microstructure and composition, eliminate material defects, and improve plasticity and ductility.

[0031] Fe Mn Si-N alloy can be prepared according to steps S10 and S20. If C and Ti are added to the raw materials in step S10, Fe Mn Si-N alloy containing C or Fe Mn Si-N alloy containing C and Ti can be prepared.

[0032] The Fe Mn Si-N alloy, or Fe Mn Si-N alloy containing C, or Fe Mn Si-N alloy containing C and Ti, prepared above, is ground to remove its outer skin and cut into regular shapes using a wire cutting machine. It can then be used to prepare biodegradable TIPS scaffolds with controllable corrosion rates.

[0033] Please see Figure 2 The following describes in detail the method of preparing biodegradable TIPS scaffolds with controllable corrosion rate using FeMnSi-N alloy, including the following steps.

[0034] S30 is used to draw Fe Mn Si-N alloy into wire to obtain Fe Mn Si-N alloy wire.

[0035] In practice, the diameter of the FeMnSi-N alloy wire is controlled between 0.10mm and 0.25mm.

[0036] S40 involves weaving Fe Mn Si-N alloy wires using a structural braiding pattern with sine curves as the basic building blocks to obtain a self-expanding Fe Mn Si-N alloy bare scaffold.

[0037] Please refer to step 3. In step S40, a sine curve is used as the basic unit to form a ring. The peaks and troughs of adjacent rings are connected to form a cylindrical self-expanding FeMnSi-N alloy bare stent. The weaving length and diameter of this self-expanding FeMnSi-N alloy bare stent are determined according to its application scenario. For example, when applied to the bile duct, its length is 40~120mm and its diameter is 6~12mm; when applied to blood vessels, its length is 60~120mm and its diameter is 6~12mm.

[0038] S50 uses a coating material to coat the self-expanding FeMnSi-N alloy bare scaffold.

[0039] For specific implementation details, please refer to [link / reference]. Figure 4 , Figure 5 One or both ends of a self-expanding FeMnSi-N alloy bare stent may not be covered. Whether the two ends of the stent are covered and the length of the uncovered length are determined according to the application scenario. Generally, 5mm to 10mm of the length of the uncovered length is left at each end of the stent. For example, when the stent is applied to a blood vessel, 20mm of the stent portal vein end is left uncovered.

[0040] In terms of biocompatibility, the coating material must be non-toxic, not cause rejection reactions, and possess excellent antithrombotic properties and cell compatibility. In terms of mechanical properties, it must have good compliance, good softness and transportability, be easily deployed to the affected area, and have sufficient tensile strength and ultra-thin thickness. In some embodiments, polycaprolactone (PCL) fibers prepared by electrospinning are used as the coating material. The diameter of the PCL fibers is less than 100 nm, and the inner diameter of the PCL fiber coating is determined according to the application scenario. For example, the inner diameter of a self-expanding FeMnSi-N alloy bare scaffold is 6 mm, so the inner diameter of the PCL fiber coating is also 6 mm. The electrospinning parameters are: voltage of 10KV~15KV, spinning distance of 20cm~30cm, and spinning solution concentration of approximately 0.5g / mL~0.9g / mL.

[0041] The technical solutions and effects of the present invention will be further described below with reference to embodiments and comparative examples. It should be noted that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] Example 1 This embodiment prepares Fe-28Mn-1Si-0.05NC-Ti alloy and self-expanding Fe-28Mn-1Si-0.05NC-Ti biliary stent grafts. The specific preparation method is shown below.

[0043] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.05wt%, the Si content is 1wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0044] S20 homogenized the bulk alloy by annealing it in a vacuum environment at 1050℃ for 5 hours to obtain the Fe-28Mn-1Si-0.05NC-Ti alloy.

[0045] The outer skin of the Fe-28Mn-1Si-0.05NC-Ti alloy from step S20 is ground off, and then cut into regular samples using a wire EDM machine. Steps S30 to S50 are performed on each sample.

[0046] S30 is used to draw Fe-28Mn-1Si-0.05NC-Ti alloy into wires with a diameter of 0.2 mm.

[0047] S40 uses Fe-28Mn-1Si-0.05NC-Ti alloy wires woven in a structural braiding pattern with a sine curve as the basic unit to obtain a self-expanding Fe-28Mn-1Si-0.05NC-Ti bare biliary stent with a length of 80mm and a diameter of 6mm.

[0048] S50 uses polycaprolactone (PCL) fibers prepared by electrospinning as a coating material to coat a self-expanding Fe-28Mn-1Si-0.05NC-Ti alloy bare scaffold, leaving 10mm uncoated at both ends of the scaffold.

[0049] Example 2 In this embodiment, Fe-28Mn-2Si-0.05NC-Ti alloy and self-expanding Fe-28Mn-2Si-0.05NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0050] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.05wt%, the Si content is 2wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0051] Example 3 In this embodiment, Fe-28Mn-1Si-0.08NC-Ti alloy and self-expanding Fe-28Mn-1Si-0.08NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0052] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.08wt%, the Si content is 1wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0053] Example 4 In this embodiment, Fe-28Mn-2Si-0.08NC-Ti alloy and self-expanding Fe-28Mn-2Si-0.08NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0054] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.08wt%, the Si content is 2wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0055] Example 5 In this embodiment, Fe-28Mn-1Si-0.1NC-Ti alloy and self-expanding Fe-28Mn-1Si-0.1NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0056] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.1wt%, the Si content is 1wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0057] Example 6 In this embodiment, Fe-28Mn-2Si-0.1NC-Ti alloy and self-expanding Fe-28Mn-2Si-0.1NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0058] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.1wt%, the Si content is 2wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0059] Comparative Example 1 In this embodiment, Fe-28Mn-0.05NC-Ti alloy and self-expanding Fe-28Mn-0.05NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0060] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.05wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0061] Comparative Example 2 In this embodiment, Fe-28Mn-0.08NC-Ti alloy and self-expanding Fe-28Mn-0.08NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0062] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.08wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0063] Comparative Example 3 In this embodiment, Fe-28Mn-0.1NC-Ti alloy and self-expanding Fe-28Mn-0.1NC-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0064] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, MnN, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the N content is 0.1wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0065] Comparative Example 4 In this embodiment, Fe-28Mn-1Si-C-Ti alloy and self-expanding Fe-28Mn-1Si-C-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0066] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the Si content is 1wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0067] Comparative Example 5 In this embodiment, Fe-28Mn-2Si-C-Ti alloy and self-expanding Fe-28Mn-2Si-C-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0068] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, Si, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the Si content is 2wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe.

[0069] Comparative Example 6 In this embodiment, Fe-28Mn-C-Ti alloy and self-expanding Fe-28Mn-C-Ti biliary stent were prepared. The preparation method was basically the same as in Example 1, except for step S10.

[0070] S10 uses an arc induction melting furnace to melt raw materials pure iron, electrolytic Mn, C, and Ti into a block alloy, wherein the Mn content is 28wt%, the C content is 0.065wt%, the Ti content is 0.07wt%, and the remainder is Fe. Results Test Analysis To verify the synergistic effect of the Si and N ratio in the Fe-Mn-Si-NC-Ti alloy, an orthogonal experimental design was employed, with Si and N included as factors. Mechanical properties of the biliary stents prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were analyzed, particularly the elastic modulus and elongation. When shape memory alloys are used in the stent field, their elastic modulus and elongation are particularly important. The elastic modulus describes a material's resistance to deformation within its elastic range, reflecting its stiffness. For stents, the elastic modulus is crucial in applications requiring high stability in maintaining a specific shape and dimensions. A suitable elastic modulus ensures that the stent does not deform excessively under normal stress, thus guaranteeing its proper support and positioning functions; for example, orthopedic implanted stents must maintain a stable support shape within the human body. If the elastic modulus is too low, the stent is prone to large deformation under small external forces, and cannot effectively support the object it carries. For example, the vascular stent cannot provide stable support for the blood vessel wall, affecting the normal shape of the blood vessel and blood flow. On the other hand, if the elastic modulus is too high, it may lead to poor mechanical compatibility with the surrounding tissues. For example, when in contact with biological tissues, it may be too rigid to adapt to the normal micro-movements of the tissues, which may easily cause adverse effects such as local stress concentration.

[0071] The elastic modulus, elongation, yield strength, tensile strength, constant voltage polarization, and open circuit voltage are tested in accordance with relevant national and industry standards.

[0072] Table 1. Effects of Si and N variations on the mechanical properties of biliary stent grafts Table 2. Range analysis of mechanical properties in Si-N synergistic changes in biliary stent grafts. The range calculation formula is R=X max -X min .

[0073] As can be seen from the table above, Fe-Mn-Si-N alloy exhibits unique comprehensive advantages in elastic modulus and elongation compared to Fe-Mn alloy, Fe-Mn-Si alloy, and Fe-Mn-N alloy.

[0074] Further analysis of the data in Tables 1 and 2 reveals that, with a constant Si content, the elastic modulus of the Fe-Mn-Si-N alloy exhibits a trend of first significantly increasing and then slowly decreasing with increasing N content, reaching an optimal value at an N content of 0.08%. With a constant N content, the elastic modulus of the Fe-Mn-Si-N alloy shows a parabolic trend with increasing Si content, reaching an optimal value at a Si content of 1%; however, with increasing N content, the influence of Si content becomes more pronounced, and the range increases rapidly.

[0075] Furthermore, with a fixed Si content, the elongation of the Fe-Mn-Si-N alloy exhibits a slight upward trend along a gentle parabola as the N content increases, reaching an optimal value at an N content of 0.08%. With a fixed N content, the elongation of the Fe-Mn-Si-N alloy shows a positive correlation with the increase in Si content, and higher ductility is beneficial for the compression and release of the support. However, with the increase in N, the influence of Si content becomes smaller and smaller, and the range decreases rapidly.

[0076] In summary, when the Si content is 1% and the N content is 0.08%, the synergistic effect of Si and N on improving the elastic modulus and elongation of Fe-Mn-Si-N alloy is significant, with the highest elastic modulus and elongation, and good compression-release effect of biliary stent graft.

[0077] Please see Figure 6 , Figure 7 Examples 1 and 4 exhibited significant corrosion activity characteristics, with their polarization current density reaching a maximum value and their open circuit potential shifting significantly negatively. This indicates that the synergistic effect of the ratio of 1Si-0.05N and 2Si-0.08N significantly enhances the corrosion driving force of the Fe-Mn-Si-N alloy, thereby greatly increasing the degradation rate of the Fe-Mn-Si-N alloy and achieving the goal of controllable degradation.

[0078] Please see Figures 8-16 ,Depend on Figures 8-13 Various embodiments and Figures 14-16 The electron micrographs of the comparison examples before and after corrosion (a and b) show that Example 6 has the best corrosion rate; after corrosion, the growth in Example 4 is evenly distributed and appears as a large-scale dotted distribution; Example 6 has the most growth and a wide distribution range.

[0079] Therefore, it can be seen that the present invention has the following beneficial effects compared with the prior art: 1) The Fe-Mn-Si-N alloy has excellent biodegradability and biocompatibility. Fe and Mn are both trace elements that are beneficial to the human body. Si is an important component of bones, teeth, hair and skin. N is a basic component of the human body. Even if C and Ti are added, Ti is physiologically inert to the human body. C is also a basic component of the human body. The scaffold material made of this alloy can be degraded in the body without toxic side effects. 2) By synergistically regulating Si and N in Fe-Mn-Si-N alloy, Fe-Mn-Si-N can effectively improve the elastic modulus and ductility of Fe-Mn-Zn-Si while meeting the requirements of CT / MRI imaging, and also ensure that the strength meets the requirements, thereby improving the elasticity, compression release effect and shape memory effect of the scaffold made of Fe-Mn-Zn-Si alloy. 3) By synergistically regulating Si and N in the Fe-Mn-Si-N alloy, the polarization current density is increased, which significantly enhances the corrosion driving force of the Fe-Mn-Si-N alloy, thereby greatly improving the degradation rate of the Fe-Mn-Si-N alloy and achieving controllable degradation.

[0080] This invention is not limited to the above-described embodiments. If any modifications or variations to this invention do not depart from the spirit and scope of this invention, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this invention, then this invention also intends to include such modifications and variations.

Claims

1. A biodegradable low-silicon ferromanganese alloy material, characterized by, The material comprises: The mass percentage of Mn is 20-30%; The mass percentage of Si is 1-2%; The mass percentage of N is 0.05-0.1%; and the balance is Fe.

2. The biodegradable low-silicon ferromanganese alloy material according to claim 1, characterized in that, Further comprising Ti, and the mass percentage of Ti is 0.05-0.1%.

3. The biodegradable low-silicon ferromanganese alloy material according to claim 1 or 2, characterized in that, Further comprising C, and the mass percentage of C is 0.05-0.1%.

4. A method for producing a biodegradable low-silicon ferromanganese alloy material, characterized by, The method comprises the following steps: S10: smelting raw materials pure iron, electrolytic Mn, MnN and Si into a blocky alloy, wherein the mass percentage of electrolytic Mn and MnN is 20-30%, the mass percentage of Si is 1-2%, the mass percentage of N is 0.05-0.1%, and the balance is Fe; S20: homogenizing annealing the blocky alloy at a set annealing temperature and annealing time in a vacuum environment to obtain an FeMn Si-N alloy.

5. The method of producing a biodegradable low-silicon ferromanganese alloy material according to claim 4, characterized by, The raw materials for smelting in step S10 further comprise C or C and Ti, wherein the mass percentage of C is 0.05-0.1%, and the mass percentage of Ti is 0.05-0.1%.

6. The method of producing a biodegradable low-silicon ferromanganese alloy material according to claim 5, characterized by, The purity of the raw materials for smelting in step S10, pure iron, electrolytic Mn, MnN, Si, C and Ti, is all ≥99.9%.

7. The method of producing a biodegradable low-silicon ferromanganese alloy material according to any one of claims 4 to 6, characterized in that, The annealing temperature is set to 1000-1100℃; the annealing time is set to 5-7 hours; the vacuum degree in vacuum environment is 10 -3 ~10 -5 Pa.

8. Application of a biodegradable low-silicon iron-manganese alloy material, characterized in that: S30: drawing the biodegradable low-silicon iron-manganese alloy material according to any one of claims 1-3 to obtain FeMn Si-N alloy wire; S40: weaving the FeMn Si-N alloy wire in a structure of a sine curve as a basic unit to obtain a self-expanding FeMn Si-N alloy bare stent; S50: coating the self-expanding FeMn Si-N alloy bare stent with a coating material.

9. Use of a biodegradable low-silicon ferromanganese alloy material according to claim 8, characterized in that, One end or both ends of the self-expanding FeMn Si-N alloy bare stent can be uncoated.

10. Use of the biodegradable low-silicon ferromanganese alloy material according to claim 8, characterized in that, The coating material is a PCL fiber prepared by electrospinning, the diameter of the PCL fiber is less than 100 nm, and the parameters of the electrospinning are as follows: the voltage is 10-15 KV, the spinning distance is 20-30 cm, and the spinning liquid concentration is about 0.5-0.9 g / mL.

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