Iron-zinc alloy biodegradable material based on powder metallurgy process and preparation method thereof

Abstract

The invention belongs to the field of biodegradable metal materials, and particularly relates to a method for preparing a degradable medical iron-zinc alloy material through a powder metallurgy process. The degradation rate of the iron-zinc alloy in simulated body fluid is 0.1-0.4 mm / year, the corrosion current density in SBF is 2-40 [mu] A / cm < 2 >, the tensile strength is 550-750 MPa, the yield strength is 500-620 MPa, the elongation at break is 5-15%, and the Vickers microhardness HV0.1 is 200-350. The iron-zinc alloy comprises the following two components in atomic percent: 85-99% of iron and 1-15% of zinc. The preparation method comprises the following steps: taking iron-zinc pre-alloy powder as a raw material, and carrying out rapid gradient hot pressing sintering molding to obtain the product. The composition is reasonable in design, the preparation process is scientific and controllable, the obtained product is excellent in performance, and industrial application is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable metallic materials, specifically relating to a method for preparing biodegradable medical iron-zinc alloy materials using powder metallurgy. Background Technology

[0002] Iron, zinc, and magnesium possess excellent biocompatibility and chemical stability, making them current research hotspots in the field of biodegradable metals. However, magnesium-based materials degrade too rapidly and are accompanied by hydrogen evolution reactions, while zinc-based materials exhibit poor mechanical stability. Iron and its alloys are a research focus for biodegradable scaffold materials. Compared to magnesium- and zinc-based biodegradable metals, iron-based biodegradable metals have higher strength, better meeting the radial support requirements of scaffolds; they also possess better plasticity, meeting the plastic deformation needs during scaffold implantation; and iron materials have better room temperature stability, maintaining the mechanical stability of scaffolds during long-term in vivo service. However, the slow degradation rate of iron-based biodegradable metals is a major factor limiting their development. Studies have shown that iron-based scaffolds remained intact for 53 months after implantation in porcine coronary arteries, significantly limiting their application. Therefore, improving the corrosion rate of iron-based materials is crucial.

[0003] Alloying is an effective method to uniformly improve the degradation rate of materials. Current research has focused on adding various alloying elements to iron, such as manganese, nitrogen, and zinc. Zinc, as the second most abundant trace element in the human body, has good biocompatibility. The standard electrode potential of zinc (-0.7628 V) is lower than that of iron (-0.4402 V). The dissolution of zinc is expected to reduce the electrode potential of iron and increase the corrosion rate of the iron matrix.

[0004] Due to the significant difference in melting and boiling points between iron and zinc, iron-zinc alloys cannot be obtained through smelting and casting. Currently, the main methods for preparing iron-zinc alloys include ion implantation, electrodeposition, and powder metallurgy. However, iron-zinc alloys prepared by ion implantation suffer from limited and uneven zinc ion implantation depth; iron-zinc alloys prepared by electrodeposition are prone to internal stress accumulation, low deposition layer density, and high alloy brittleness. Currently, Fe-Zn alloys prepared by powder metallurgy, such as those described in CN102634725A, utilize powder metallurgy technology to obtain Fe-Zn binary alloys with tensile strengths of 300–400 MPa and degradation rates of 0.25–0.45 mm / y. Summary of the Invention

[0005] To address the shortcomings of current biodegradable Fe-Zn alloys, this invention provides a biodegradable Fe-Zn alloy with tensile and yield strengths greater than 500 MPa and a degradation rate of 0.2-0.4 mm / year, and also develops a matching preparation process.

[0006] This invention addresses the technical problems of uneven composition, low tensile / yield strength, and high brittleness in existing iron-zinc alloys by optimizing composition and process parameters, thereby obtaining an iron-zinc alloy biodegradable material with good mechanical strength and a suitable degradation rate.

[0007] This invention utilizes a powder metallurgy process combining mechanical alloying with rapid hot pressing sintering to produce an iron-zinc alloy with a quantitatively adjustable degradation rate. This alloy possesses excellent mechanical properties and biocompatibility, and has broad prospects and application value in the field of biodegradable implantable materials such as orthopedic implants, vascular stents, and esophageal stents.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A biodegradable iron-zinc alloy material based on powder metallurgy, wherein the iron-zinc alloy exhibits a degradation rate of 0.1-0.4 mm / year in simulated body fluid (SBF) and a corrosion current density of 2-40 μA / cm² in SBF. 2 Tensile strength is 550-750 MPa, yield strength is 500-620 MPa, elongation at break is 5-15%, and Vickers microhardness is HV. 0.1 It is 200-350, and comprises the following two components by atomic percentage: 85-99% iron and 1-15% zinc.

[0010] In a preferred embodiment, the iron-zinc alloy has a tensile strength of 550–650 MPa and an elongation at break of 8–12%.

[0011] In a preferred embodiment, the degradation rate of the iron-zinc alloy is 0.2-0.4 mm / year.

[0012] In a preferred embodiment, the Vickers microhardness HV of the iron-zinc alloy is... 0.1 It is 250-300.

[0013] In a preferred embodiment, the density of the iron-zinc alloy is 93-98%.

[0014] In a preferred embodiment, the iron-zinc alloy comprises, by atomic percentage, the following components: 90-97.5% iron and 2.5-10% zinc. More preferably, the iron-zinc alloy has an iron atomic percentage of 94-96% and a zinc atomic percentage of 4-6%. Even more preferably, the iron-zinc alloy has an iron atomic percentage of 95% and a zinc atomic percentage of 5%.

[0015] In a preferred embodiment, the iron-zinc alloy is prepared by rapidly hot-pressing and sintering iron-zinc pre-alloyed powder to obtain the desired biodegradable implant material.

[0016] The iron-zinc alloy designed and selected in this invention is superior to pure iron in terms of corrosion resistance, mechanical properties, and biocompatibility.

[0017] This invention discloses a method for preparing a biodegradable iron-zinc alloy, comprising the following steps:

[0018] Step 1 (Mechanical Alloying): The raw materials are iron powder and zinc powder. Using a planetary ball mill and a stainless steel vacuum ball milling jar, the iron-zinc mixed powder of different components is ball-milled for at least 10 hours. The ball milling speed is 200-300 rpm, the ball-to-material mass ratio is 8-12:1, preferably 10:1, and the ball milling atmosphere is a protective atmosphere. After ball milling, the powder is sieved to obtain a spare powder. The spare powder is an iron-zinc pre-alloyed powder with a particle size of less than or equal to 74 μm.

[0019] Step 2 (Rapid Hot Press Sintering): The prepared powder is shaped by hot pressing sintering. Sintering process: First, a vacuum is drawn until the vacuum degree is less than 10. -1 Pa, then heated and pressurized to a pressing pressure of 20-50 MPa, sintered at a temperature of 600-1200 ℃. After sintering, the sample is cooled in the furnace to 200-300 ℃, the pressure is released, and then cooled to room temperature. Demolding yields the iron-zinc alloy biodegradable material.

[0020] Preferably, in step one, the purity of the iron powder is greater than or equal to 99.9% (mass percentage), and its particle size is preferably less than or equal to 45 micrometers.

[0021] Preferably, in step one, the purity of the zinc powder is greater than or equal to 99.9% (mass percentage), and its particle size is preferably less than or equal to 45 micrometers.

[0022] Preferably, the ball milling time in step one is greater than 20 hours, including 30 to 60 hours, and more preferably 35 to 45 hours.

[0023] Preferably, in step one, the protective atmosphere is either a nitrogen atmosphere or an argon atmosphere.

[0024] Preferably, the sintering temperature in step two is 800-1000 ℃, the sintering holding time is 5-30 min, and the heating rate is 50-150 ℃ / min;

[0025] Preferably, the specific sintering process in step two is as follows: the mixed powder is filled into a graphite mold, the mold is wrapped with graphite felt, the temperature is measured by a thermocouple, and the mold is placed in a sintering furnace for pre-pressing for 10-20 seconds (pressure not exceeding 40 MPa). The pre-pressed mixed powder blank is then evacuated until the vacuum degree inside the furnace is less than or equal to 10 MPa. -1The pressure is then increased to 400 °C, with the pressure controlled at 5-15 MPa during this stage. The pressure is then increased to 20-50 MPa, followed by heating to the sintering temperature and sintering for 10-20 min. The heating rate is 60-130 °C / min, and the sintering temperature is 800-1000 °C, more preferably 800-950 °C. In industrial applications, a sintering temperature of 800-900 °C can be used.

[0026] The specific sintering process in step two can be optimized as follows: The pre-pressed mixed powder blank is then evacuated until the vacuum level inside the furnace is less than or equal to 10. -1 Pa, then perform the following operations:

[0027] The first stage involves heating to 400 °C at a rate of 100 °C / min, with a pressure of 7 MPa (initial stage); the second stage involves increasing the pressure to 50 MPa at a rate of 21.5 MPa / min, maintaining the temperature at 400 °C; the third stage involves heating to 700 °C at a rate of 75 °C / min, with a pressure of 50 MPa; the fourth stage involves heating to the target temperature of 900 °C at a rate of 50 °C / min, with a pressure of 50 MPa; the final stage involves holding at 900 °C and 50 MPa for 8 min. After sintering, the sample is cooled to 300 °C in the furnace, followed by air cooling to room temperature; or

[0028] The first stage involves heating to 400 °C at a rate of 100 °C / min, with a pressure of 7 MPa (initial stage); the second stage involves increasing the pressure to 50 MPa at a rate of 21.5 MPa / min, maintaining the temperature at 400 °C; the third stage involves heating to 700 °C at a rate of 75 °C / min, with a pressure of 50 MPa; the fourth stage involves heating to the target temperature of 875 °C at a rate of 60 °C / min, with a pressure of 50 MPa; the final stage involves holding at 875 °C and 50 MPa for 10 min; after sintering, the sample is cooled to 300 °C in the furnace, followed by air cooling to room temperature; or

[0029] The first stage involves heating to 400 °C at a rate of 100 °C / min and applying a pressure of 7 MPa (initial stage); the second stage involves increasing the pressure to 50 MPa at a rate of 21.5 MPa / min and maintaining the temperature at 400 °C; the third stage involves heating to 700 °C at a rate of 75 °C / min and applying a pressure of 50 MPa; the fourth stage involves heating to the target temperature of 800 °C at a rate of 50 °C / min and applying a pressure of 50 MPa; the final stage involves holding at 800 °C and 50 MPa for 12 min; after sintering, the sample is cooled to 300 °C in the furnace and then air-cooled to room temperature.

[0030] As a further preferred option, the sintering pressure is 30-50 MPa at the sintering temperature.

[0031] The iron-zinc alloy biodegradable material of this invention is prepared by a powder metallurgy method combining mechanical alloying and rapid hot pressing sintering. Mechanical alloying can effectively alloy elements with large differences in melting point at room temperature. The standard electrode potential of zinc (-0.7628 V) is lower than that of iron (-0.4402 V). The dissolution of zinc can reduce the electrode potential of iron and increase the corrosion rate of the iron matrix. Solid solution strengthening and precipitation strengthening can also be achieved through the solid solution of zinc and the precipitation of intermetallic compounds, thereby improving the mechanical properties of the alloy. Both iron and zinc play important biological roles in the human body, and this binary alloy ensures the biosafety requirements of the material. This invention controls the degree of zinc solid solution and the grain size of the mixed powder by adjusting the ball milling time in step one. Then, by adjusting the sintering temperature and holding time in step two, the grain size of the sintered iron-zinc alloy can be controlled, further adjusting the degree of zinc solid solution and effectively controlling the mechanical properties of the iron-zinc alloy. Subsequently, by subjecting the iron-zinc alloy to heat treatment and hot deformation with different process parameters, the amount and distribution of the second phase precipitation can be effectively adjusted, thereby effectively controlling the degradation rate and mechanical properties of the Fe-Zn alloy, which can match different biological environments and functional requirements.

[0032] Therefore, the iron-zinc alloy designed and prepared in this invention possesses high mechanical strength, with a tensile strength of 550-750 MPa, a yield strength of 500-620 MPa, and an elongation at break of 8-12%; it also exhibits good biological corrosion resistance, with a degradation rate of 0.2-0.4 mm / year in simulated body fluid SBF; and excellent biocompatibility. It can meet the needs of biomedical applications such as vascular stents, esophageal stents, and intraosseous implants.

[0033] This invention is the first to achieve the production of excellent products with tensile strength of 555-685 MPa, yield strength of 520-600 MPa and corrosion rate of 0.23-0.29 mm / year with a small amount of Zn, such as 1.25-2.5%.

[0034] This invention is the first to achieve a product with a tensile strength of 600-692 MPa, a yield strength of 545-615 MPa, and a corrosion rate of 0.37-0.38 mm / year by adding 5% Zn.

[0035] Beneficial effects

[0036] This invention provides a biodegradable iron-zinc alloy material based on powder metallurgy and its preparation method, which has the following significant advantages compared with the prior art:

[0037] (1) By using mechanical alloying ball milling (200-300 r / min, time > 20 h) and rapid hot pressing sintering (700-1000℃), iron (1535℃) and zinc (419℃), which have significantly different melting points, can be uniformly mixed, solving the problem of component segregation caused by the easy volatilization of zinc in traditional smelting methods. In the iron-zinc alloy prepared by this process, the iron content reaches 80-99% and the zinc content is 1-20%, ensuring the synergistic optimization of mechanical properties and degradation rate, especially making the product have excellent tensile strength and yield strength and an appropriate degradation rate;

[0038] (2) Powder metallurgy process precisely controls the element content by accurately weighing the ratio of iron powder to zinc powder, improves the uniformity of material distribution, significantly increases the material density (>93%), reduces the introduction of impurities, and avoids the problem of enhanced corrosion resistance caused by oxygen atom doping in traditional processes such as electrodeposition;

[0039] (3) This invention uses mechanical alloying to dissolve zinc in iron, which reduces the electrode potential of the iron matrix and accelerates electrochemical corrosion, thereby accelerating the degradation of the iron matrix. At the same time, zinc, as an essential trace element, participates in human metabolism, and the degradation products are non-toxic and have excellent biocompatibility.

[0040] (4) Environmental friendliness and cost-effectiveness: Powder metallurgy has low energy consumption and controllable process. Compared with smelting or electrodeposition, it is easier to scale up production and reduce manufacturing costs. Attached Figure Description

[0041] Figure 1 This is a SEM image showing the microstructure of the powder obtained after ball milling in Example 1.

[0042] Figure 2 The graph shows the potentiodynamic polarization curve of the product obtained in Example 1 in SBF simulated body fluid;

[0043] Figure 3 The fracture morphology diagram is shown for the product obtained in Example 2.

[0044] Figure 4 The image shows the XRD pattern of the powder obtained after ball milling in Example 3.

[0045] Figure 5 The graph shows the potentiodynamic polarization curve of the product obtained in Example 3 in SBF simulated body fluid;

[0046] Figure 6 The image shows the surface corrosion morphology of the product obtained in Example 3 after immersion in SBF at room temperature for 28 days.

[0047] Figure 7 SEM image of L929 cells directly attached to the surface of the product obtained in Example 3 after 4 hours. Detailed Implementation

[0048] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0049] In this invention, the ball mill used is a YXQM-4L planetary ball mill, and the raw materials used are pure iron powder (99.9%, particle size <45μm) and pure zinc powder (99.9%, particle size <45μm), and an FHP-828 rapid hot pressing sintering furnace is used.

[0050] Example 1

[0051] Iron-zinc alloy biodegradable materials were prepared using powder metallurgy. The zinc powder atomic percentage was 1.25%, the ball-to-powder ratio was 10:1, and the total powder weight was 60 g (0.87 g zinc powder and 59.13 g iron powder). Ball milling was performed using a planetary ball mill in a vacuum stainless steel jar under 99.9% high-purity argon protection at a speed of 300 r / min for 40 h, yielding an iron-zinc supersaturated solid solution powder. The powder was sieved through a 200-mesh sieve, yielding powder with a particle size smaller than 74 μm. The microstructure of the milled powder is shown in the attached figure. Figure 1 The particles are dispersed, and within the frame, the particle diameter is mainly distributed between 5-30 μm.

[0052] The above-mentioned supersaturated iron-zinc alloy powder was placed in a rapid hot pressing sintering furnace, and the vacuum degree during the sintering process was <10. -1 A zinc-iron alloy was prepared by sintering at a temperature of 875 °C, a holding time of 10 min, and a sintering pressure of 50 MPa. The sintering process employed a gradient heating method, as follows: In the first stage, the temperature was increased to 400 °C at a rate of 100 °C / min, with a pressure of 7 MPa (initial stage); in the second stage, the pressure was increased to 50 MPa at a rate of 21.5 MPa / min, while maintaining the temperature at 400 °C; in the third stage, the temperature was increased to 700 °C at a rate of 75 °C / min, with a pressure of 50 MPa; in the fourth stage, the temperature was increased to the target temperature of 875 °C at a rate of 60 °C / min, with a pressure of 50 MPa; the final holding time was 10 min at 875 °C and 50 MPa; after sintering, the sample was cooled to 300 °C in the furnace and then air-cooled to room temperature.

[0053] Results: The density of the sintered alloy, measured by the water displacement method, was 95.2%. Phase analysis of the ball-milled powder and the sintered iron-zinc alloy revealed only iron diffraction peaks, indicating that zinc was completely dissolved in the iron matrix. The alloy material exhibited a yield strength of 517.6 ± 10.3 MPa, an ultimate tensile strength of 572.4 ± 12.4 MPa, an elongation at break of 10.8 ± 0.3%, and a high HV. 0.1 It is 264.3 ± 6.6. (See attached image) Figure 2 Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.74±0.05 V, and the corrosion current density was 30.6±2.2 μA / cm. 2 The corrosion rate of the alloy after 28 days of immersion in SBF was measured to be 0.23 mm / year by the weight loss method.

[0054] Example 1-1

[0055] All other conditions are the same as in Example 1, except that the zinc powder content is 5 at.%.

[0056] The yield strength of the obtained product was 554.3±6.4 MPa, the ultimate tensile strength was 612.4±11.7 MPa, the elongation at break was 8.9±0.4%, and the HV was... 0.1 The value was 287.5 ± 6.3. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.81 ± 0.02 V, and the corrosion current density was 35.4 ± 1.5 μA / cm. 2 .

[0057] Examples 1-2

[0058] The other conditions are the same as in Example 1, except that the ball milling speed is 200 rpm and the ball milling time is 60 h.

[0059] The yield strength of the obtained product was 532.7±9.4 MPa, the ultimate tensile strength was 602.3±10.4 MPa, the elongation at break was 11.9±0.4%, and the HV was... 0.1 The value was 283.5 ± 7.4. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.74 ± 0.03 V, and the corrosion current density was 34.61 ± 2.4 μA / cm. 2 .

[0060] Example 2

[0061] Iron-zinc alloy biodegradable materials were prepared using powder metallurgy. The zinc powder atomic percentage was 2.5%, the ball-to-powder ratio was 10:1, and the total powder weight was 60 g (1.73 g zinc powder and 58.27 g iron powder). Ball milling was performed using a planetary ball mill in a vacuum stainless steel jar under 99.9% high-purity argon gas protection at 300 r / min for 40 h, yielding an iron-zinc supersaturated solid solution powder. The powder was sieved through a 200-mesh sieve to obtain powder with a particle size smaller than 74 μm.

[0062] The above-mentioned supersaturated iron-zinc alloy powder was placed in a rapid hot pressing sintering furnace, and the vacuum degree during the sintering process was <10. -1A zinc-iron alloy was prepared by sintering at 800 °C for 12 min under a pressure of 50 MPa. The sintering process employed a gradient heating method, as follows: In the first stage, the temperature was increased to 400 °C at a rate of 100 °C / min, with a pressure of 7 MPa (initial stage); in the second stage, the pressure was increased to 50 MPa at a rate of 21.5 MPa / min, while maintaining the temperature at 400 °C; in the third stage, the temperature was increased to 700 °C at a rate of 75 °C / min, with a pressure of 50 MPa; in the fourth stage, the temperature was increased to the target temperature of 800 °C at a rate of 50 °C / min, with a pressure of 50 MPa; the final holding temperature was 800 °C at 50 MPa for 12 min; after sintering, the sample was cooled to 300 °C in the furnace and then air-cooled to room temperature.

[0063] Results: The density of the sintered alloy, measured by the water displacement method, was 94.1%. Phase analysis of the ball-milled powder and the sintered iron-zinc alloy revealed only iron diffraction peaks, indicating that zinc was completely dissolved in the iron matrix. (See attached image) Figure 3 The fracture morphology of this alloy was determined by tensile testing. The yield strength was 589.4 ± 8.1 MPa, the ultimate tensile strength was 672.5 ± 9.3 MPa, the elongation at break was 5.4 ± 1.2%, and the HV was [missing value]. 0.1 The value was 314.3 ± 15.6. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.78 ± 0.04 V, and the corrosion current density was 36.5 ± 1.4 μA / cm. 2 The corrosion rate of the alloy after 28 days of immersion in SBF was determined to be 0.29 mm / year by the weight loss method.

[0064] Example 2-1

[0065] The other conditions are the same as in Example 2, except that the zinc powder content is 5 at%, and the ball milling speed is 200 rpm.

[0066] The yield strength of the obtained product was 601.15±12.6 MPa, the ultimate tensile strength was 685.2±5.3 MPa, the elongation at break was 2.4±0.6%, and the HV was... 0.1 The value was 325.3 ± 8.5. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.74 ± 0.03 V, and the corrosion current density was 31.5 ± 2.3 μA / cm. 2 .

[0067] Example 3

[0068] Iron-zinc alloy biodegradable materials were prepared using powder metallurgy. The zinc powder had an atomic percentage of 5%, a ball-to-powder ratio of 10:1, and a total powder weight of 60 g (3.46 g zinc powder and 56.5 g iron powder). Ball milling was performed using a planetary ball mill in a vacuum stainless steel jar under 99.9% high-purity argon gas protection at a speed of 300 r / min for 40 h. The resulting supersaturated iron-zinc solid solution powder was obtained.

[0069] The above-mentioned supersaturated iron-zinc alloy powder was placed in a rapid hot pressing sintering furnace, and the vacuum degree during the sintering process was <10. -1 A zinc-iron alloy was prepared by sintering at a temperature of 900 °C, a holding time of 8 min, and a sintering pressure of 50 MPa. The sintering process employed a gradient heating method, as follows: In the first stage, the temperature was increased to 400 °C at a rate of 100 °C / min, with a pressure of 7 MPa (initial stage); in the second stage, the pressure was increased to 50 MPa at a rate of 21.5 MPa / min, while maintaining the temperature at 400 °C; in the third stage, the temperature was increased to 700 °C at a rate of 75 °C / min, with a pressure of 50 MPa; in the fourth stage, the temperature was increased to the target temperature of 900 °C at a rate of 50 °C / min, with a pressure of 50 MPa; the final holding time was 8 min at 900 °C and 50 MPa. After sintering, the sample was cooled to 300 °C in the furnace and then air-cooled to room temperature.

[0070] Implementation Results: The density of the sintered alloy, measured by the water displacement method, was 96.3%, as shown in the attached figure. Figure 4 XRD analysis of the ball-milled powder and the sintered iron-zinc alloy revealed only iron diffraction peaks, indicating that zinc is completely dissolved in the iron matrix. Tensile tests showed that the material's yield strength was 562.2 ± 6.3 MPa, ultimate tensile strength was 635.8 ± 4.5 MPa, elongation at break was 10.4 ± 1.4%, and HV was [missing value]. 0.1 It is 287.7 ± 11.6. (See attached image) Figure 5 The potentiodynamic polarization curves of the alloy in SBF are shown. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in simulated body fluid in SBF is -0.82±0.05 V, and the corrosion current density is 40.5±2.2 μA / cm. 2 The corrosion rate of the alloy after 28 days of immersion in SBF was determined to be 0.38 mm / year by the weight loss method, as shown in the attached figure. Figure 6 The image shows the surface corrosion morphology of the alloy after immersion in SBF for 28 days. Cell adhesion experiments were performed, as shown in the attached... Figure 7 The image shows a SEM image of L929 cells cultured directly on the material surface for 4 hours. The alloy has good biocompatibility, and fibroblasts can adhere well to the material surface.

[0071] Example 3-1

[0072] The other conditions are the same as in Example 3, except that the sintering temperature is 950 °C, the holding time is 10 min, the ball milling speed is 200 rpm, and the ball milling time is 40 h.

[0073] The yield strength of the obtained product was 564.4±6.8 MPa, the ultimate tensile strength was 645.3±5.6 MPa, the elongation at break was 8.9±0.3%, and the HV was... 0.1 The value was 293.5 ± 5.5. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.72 ± 0.04 V, and the corrosion current density was 35.44 ± 3.5 μA / cm. 2 .

[0074] Comparative Example 1

[0075] Other conditions were the same as in Example 1, except that gradient temperature sintering was not used. Instead, the temperature was increased to 875°C at a rate of 75°C / min, held for 10 minutes, and the pressure was 50 MPa.

[0076] The yield strength of the obtained product was 230.2±9.4 MPa, the ultimate tensile strength was 272.8±8.4 MPa, and the elongation at break was 2.3±0.5%. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.67±0.06 V, and the corrosion current density was 20.7±1.6 μA / cm. 2 .

[0077] Comparative Example 2

[0078] The other conditions are the same as in Example 2, except that the powder was not sieved after ball milling, and powders with different particle sizes were used for sintering.

[0079] The yield strength of the obtained product was 459.3±4.6 MPa, the ultimate tensile strength was 522.6±10.3 MPa, and the elongation at break was 4.2±0.8%. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.69±0.03 V, and the corrosion current density was 21.3±2.4 μA / cm. 2 .

[0080] Comparative Example 3

[0081] The other conditions are the same as in Example 3, except that the atomic percentage of zinc powder is 15%.

[0082] The yield strength of the obtained product was 343.3±6.8 MPa, the ultimate tensile strength was 416.3±19.1 MPa, and the elongation at break was 1.3±0.5%. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.78±0.03 V, and the corrosion current density was 38.4±3.4 μA / cm. 2 .

[0083] Comparative Example 4

[0084] The other conditions are the same as in Example 3, except that the iron powder and zinc powder are not ball-milled, but are directly placed in a rapid hot-pressing sintering furnace for sintering.

[0085] The yield strength of the obtained product was 372.2±3.6 MPa, the ultimate tensile strength was 436.4±10.4 MPa, and the elongation at break was 7.3±0.4%. Electrochemical analysis revealed that the corrosion potential of the iron-zinc alloy in SBF simulated body fluid was -0.53±0.02 V, and the corrosion current density was 7.8±0.13 μA / cm. 2 .

[0086] The above-disclosed embodiments are merely a few examples of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A biodegradable iron-zinc alloy material based on powder metallurgy, characterized in that: The degradation rate of the iron-zinc alloy in simulated body fluid SBF was 0.1-0.4 mm / year, and the corrosion current density in SBF was 2-40 μA / cm. 2 Tensile strength is 550-750 MPa, yield strength is 500-620 MPa, elongation at break is 5-15%, and Vickers microhardness is HV. 0.1 The value is 200-350, and the iron-zinc alloy comprises the following two components by atomic percentage: 85-99% iron and 1-15% zinc.

2. The iron-zinc alloy biodegradable material based on powder metallurgy process according to claim 1, characterized in that: The iron-zinc alloy has a tensile strength of 550–650 MPa and an elongation at break of 8–12%.

3. The iron-zinc alloy biodegradable material based on powder metallurgy process according to claim 1, characterized in that: The degradation rate of the iron-zinc alloy is 0.2-0.4 mm / year.

4. The iron-zinc alloy biodegradable material based on powder metallurgy process according to claim 1, characterized in that: The Vickers microhardness HV of the iron-zinc alloy 0.1 It is 250-300.

5. The iron-zinc alloy biodegradable material based on powder metallurgy process according to claim 1, characterized in that: The density of the iron-zinc alloy is 93-98%.

6. The iron-zinc alloy biodegradable material based on powder metallurgy process according to claim 1, characterized in that: The iron-zinc alloy comprises, by atomic percentage, the following components: 90-97.5% iron and 2.5-10% zinc. More preferably, the iron-zinc alloy has an iron atomic percentage of 94-96% and a zinc atomic percentage of 4-6%. Even more preferably, the iron-zinc alloy has an iron atomic percentage of 95% and a zinc atomic percentage of 5%.

7. A method for preparing a biodegradable iron-zinc alloy material as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Mechanical alloying The raw materials are iron powder and zinc powder. The mixed iron-zinc powders of different components are ball-milled for at least 10 hours using a planetary ball mill and a stainless steel vacuum ball milling jar. The ball milling speed is 200-300 rpm, the ball-to-material mass ratio is 8-12:1, preferably 10:1, and the ball milling atmosphere is a protective atmosphere. After ball milling, the powder is sieved to obtain a spare powder. The spare powder is an iron-zinc alloy powder with a particle size of less than or equal to 74 μm. Step 2: Rapid hot pressing and sintering The prepared powder is shaped by hot pressing and sintering. The sintering process involves first evacuating the vacuum to a degree less than 10. -1 Pa, then heated and pressurized to a pressing pressure of 20-50 MPa, sintered at a temperature of 600-1200 ℃. After sintering, the sample is cooled in the furnace to 200-300 ℃, the pressure is released, and then cooled to room temperature. Demolding yields the iron-zinc alloy biodegradable material.

8. The method for preparing a biodegradable iron-zinc alloy material based on powder metallurgy according to claim 7, characterized in that: In step one, the purity of the iron powder is greater than or equal to 99.9%, and its particle size is preferably less than or equal to 45 micrometers; In step one, the purity of the zinc powder is greater than or equal to 99.9%, and its particle size is preferably less than or equal to 45 micrometers; The ball milling time in step one is greater than 20 hours, including 30 to 60 hours, and more preferably 35 to 45 hours; In step one, the protective atmosphere is either nitrogen or argon.

9. The method for preparing a biodegradable iron-zinc alloy material based on powder metallurgy according to claim 7, characterized in that: The sintering temperature for step two is 800-1000 ℃, the sintering holding time is 5-30 min, and the heating rate is 50-150 ℃ / min.

10. The method for preparing a biodegradable iron-zinc alloy material based on powder metallurgy according to claim 7, characterized in that: The sintering process in step two is as follows: The mixed powder is loaded into a graphite mold, the mold is wrapped with graphite felt, and the temperature is measured by a thermocouple. The mold is then placed in a sintering furnace for pre-compression for 10-20 seconds, at which point the pressure should not exceed 40 MPa. The pre-compressed mixed powder blank is then evacuated until the vacuum level inside the furnace is less than or equal to 10 MPa. -1 The pressure is then increased to 400 °C, with the pressure controlled at 5-15 MPa during this stage. The pressure is then increased to 20-50 MPa, followed by heating to the sintering temperature and sintering for 10-20 min. The heating rate is 60-130 °C / min, and the sintering temperature is 800-1000 °C, more preferably 800-950 °C. In industrial applications, a sintering temperature of 800-900 °C can be used.

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