Biomedical titanium alloy with micro-arc oxidation surface modification and preparation method thereof

Abstract

The application discloses a micro-arc oxidation surface modified biomedical titanium alloy with good friction corrosion resistance and a preparation method thereof. The micro-arc oxidation surface modified biomedical titanium alloy comprises a titanium alloy base material and a micro-arc oxidation coating layer on the surface of the titanium alloy base material; the micro-arc oxidation coating layer comprises a compact layer and a sparse layer connected with the titanium alloy base material in sequence; the micro-arc oxidation coating layer contains sodium element, oxygen element, aluminum element, phosphorus element, potassium element, titanium element and niobium element through EDS element analysis. The preparation method comprises the following steps: preparing a micro-arc oxidation electrolyte, wherein the micro-arc oxidation electrolyte comprises sodium titanate, potassium hydroxide, sodium hexametaphosphate and niobium particles; taking the titanium alloy base material as an anode, taking a stainless steel sheet as a cathode, loading the micro-arc oxidation electrolyte into an electrolytic tank, and then performing a micro-arc oxidation electrolytic reaction to generate the micro-arc oxidation coating layer on the surface of the titanium alloy base material.

Description

Technical Field

[0001] This invention relates to the technical field of biomedical titanium alloys, and more specifically, to biomedical titanium alloys with micro-arc oxidation surface modification and their preparation methods. Background Technology

[0002] Titanium alloy TC4 (Ti6Al4V) is widely used in biomedical devices, orthopedic implants, and other fields due to its high strength, high biocompatibility, and low density. However, titanium alloys suffer from relatively low surface hardness and poor wear resistance. In practical engineering, relative movement has been observed between titanium alloy connecting parts, causing frictional wear, such as at the head and neck contact interface of artificial hip joints. This damage can evolve into frictional corrosion under the influence of bodily fluids. Frictional corrosion refers to the surface deterioration of materials caused by the combined effects of corrosion and wear. Frictional corrosion of titanium alloys will cause surface material loss, deteriorate the service condition of components, and even lead to component failure. Therefore, improving the surface properties of titanium alloys and reducing their surface frictional corrosion damage is crucial.

[0003] Micro-arc oxidation (MAO) surface modification technology is widely used to improve the surface properties of titanium alloys due to its simple process, high efficiency, strong controllability, and environmental friendliness. MAO technology can generate various types of coatings on titanium alloy surfaces by changing the type of electrolyte, thereby endowing titanium with specific surface properties. Currently, existing technologies have obtained coatings with varying properties such as corrosion resistance, wear resistance, and high-temperature oxidation resistance on titanium alloy surfaces by adding different MAO electrolytes. However, current technologies focus primarily on the performance of titanium alloy surface coatings based on single high-temperature oxidation resistance, corrosion resistance, and wear resistance; the tribocorrosion performance of titanium alloys under the combined effects of corrosion and wear has not yet been reported. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a micro-arc oxidation surface-modified biomedical titanium alloy with good friction and corrosion resistance, as well as its preparation method and friction and corrosion resistance testing method.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a biomedical titanium alloy with micro-arc oxidation surface modification is provided, the technical solution of which is as follows:

[0006] A biomedical titanium alloy with micro-arc oxidation surface modification includes a titanium alloy substrate and a micro-arc oxidation coating on the surface of the titanium alloy substrate; the micro-arc oxidation coating includes a dense layer and a sparse layer connected sequentially to the titanium alloy substrate; EDS elemental analysis shows that the micro-arc oxidation coating contains sodium, oxygen, aluminum, phosphorus, potassium, titanium and niobium.

[0007] As a further improvement to the above-mentioned micro-arc oxidation surface-modified biomedical titanium alloy: the thickness of the dense layer is 7-9 μm, and the thickness of the sparse layer is 7-9 μm.

[0008] As a further improvement to the above-mentioned micro-arc oxidation surface-modified biomedical titanium alloy, the mass fractions of sodium, oxygen, aluminum, phosphorus, potassium, titanium and niobium in the micro-arc oxidation coating are 0.91%, 43.92%, 8.64%, 1.14%, 0.45%, 29.62% and 15.32%, respectively.

[0009] As a further improvement to the above-mentioned micro-arc oxidation surface modification of biomedical titanium alloy: the micro-arc oxidation coating has a porous structure with a pore size of 0.5 to 4 μm and a net distance of 0.5 to 3 μm between two adjacent pores.

[0010] As a further improvement to the above-mentioned micro-arc oxidation surface modification of biomedical titanium alloy: XRD phase analysis revealed that the phases contained in the micro-arc oxidation coating include TiO2, Al2TiO5, NbTi4, and Nb2O5.

[0011] As a further improvement to the aforementioned micro-arc oxidation surface-modified biomedical titanium alloy: the mass fraction of each element in the titanium alloy substrate is as follows: aluminum 6.05%, vanadium 3.95%, iron 0.11%, carbon 0.014%, oxygen 0.14%, nitrogen 0.006%, hydrogen 0.001%, and titanium 89.729%; the tensile strength of the titanium alloy substrate is 860 MPa, the yield strength is 795 MPa, the elongation is 12%, the elastic modulus is 110 GPa, and the Poisson's ratio is 0.3; the surface roughness Ra of the titanium alloy substrate is ≤0.1 μm.

[0012] To achieve the above objectives, according to a second aspect of the present invention, a method for preparing a micro-arc oxidation surface-modified biomedical titanium alloy is provided, the technical solution of which is as follows:

[0013] The preparation method of the micro-arc oxidation surface-modified biomedical titanium alloy described in the first aspect above includes the following steps: preparing a micro-arc oxidation electrolyte, wherein the micro-arc oxidation electrolyte includes sodium titanate, potassium hydroxide, sodium hexametaphosphate and niobium particles; using a titanium alloy substrate as the anode and a stainless steel sheet as the cathode, loading the micro-arc oxidation electrolyte into an electrolytic cell, and then performing a micro-arc oxidation electrolysis reaction, that is, generating a micro-arc oxidation coating on the surface of the titanium alloy substrate.

[0014] As a further improvement to the preparation method of the above-mentioned micro-arc oxidation surface-modified biomedical titanium alloy: the concentration of each component in the micro-arc oxidation electrolyte is as follows: sodium titanate 5-7 g / L, potassium hydroxide 3-5 g / L, sodium hexametaphosphate 1-3 g / L, niobium particles 5-7 g / L; the particle size of the niobium particles is 40-60 nm.

[0015] As a further improvement to the preparation method of the above-mentioned micro-arc oxidation surface-modified biomedical titanium alloy: the micro-arc oxidation electrolysis reaction adopts a constant voltage mode, with a voltage of 350V, a frequency of 500Hz, a duty cycle of 50%, a reaction time of 30min, and an electrolysis temperature of 30℃.

[0016] As a further improvement to the preparation method of the above-mentioned micro-arc oxidation surface modified biomedical titanium alloy, it also includes pretreatment of the titanium alloy substrate surface: firstly, it is polished in sequence on a polishing machine with 600#, 1000#, 1500# and 2000# sandpaper, and then precision polished with W2.5 diamond polishing paste and a cloth polishing disc with a roughness of 3000#.

[0017] To achieve the above objectives, according to a third aspect of the present invention, a method for testing the friction and corrosion resistance of micro-arc oxidation surface-modified biomedical titanium alloys is provided, the technical solution of which is as follows:

[0018] The method for testing the friction and corrosion resistance of the micro-arc oxidation surface-modified biomedical titanium alloy described in the first aspect above is carried out in a micro-motion test device, using CoCrMo alloy as the grinding pair material, and conducting friction and corrosion tests in simulated body fluid.

[0019] As a further improvement to the test method for the friction and corrosion resistance of the aforementioned magnetron sputtering modified biomedical titanium alloy: the CoCrMo alloy has a tensile strength of 1507 MPa, a yield strength of 962 MPa, an elongation of 20%, an elastic modulus of 200 GPa, and a Poisson's ratio of 0.3; the mass fractions of each element in the CoCrMo alloy are: chromium 28.10 wt%, molybdenum 5.90 wt%, nickel 0.88 wt%, iron 0.65 wt%, manganese 0.63 wt%, silicon 0.22 wt%, carbon 0.25 wt%, nitrogen 0.12 wt%, and cobalt 63.25%; the concentrations of each component in the simulated body fluid are: Na... + 142.0mM, K + 5mM, Mg 2+ 1.5mM, Ca 2+ 2.5mM, Cl - The concentration was 147.8 mM, and the concentration of HCO3 was 147.8 mM. - 4.2mM, HPO4 2-1.0 mM, SO4 2- It is 0.5mM.

[0020] The present invention has the following beneficial effects:

[0021] Niobium has advantages such as chemical stability, good biocompatibility, strong corrosion resistance, and good high-temperature oxidation resistance. This invention utilizes micro-arc oxidation technology to successfully introduce niobium onto the surface of a titanium alloy substrate for the first time, forming a niobium-containing micro-arc oxidation coating. This coating consists of a dense layer and a sparse layer with a porous structure. The coating has uniform thickness and elemental distribution, and there are no cracks, delamination, or other damage on the surface or inside. The coating-substrate bond is good.

[0022] Verification has shown that, compared to unmodified titanium alloy substrates, the micro-arc oxidation coating introduced in this invention can form a novel hard phase, reducing the friction coefficient, frictional corrosion material loss, open-circuit potential change, and corrosion current on the titanium alloy substrate surface. Therefore, the micro-arc oxidation surface-modified biomedical titanium alloy prepared by this invention has significantly better microhardness, fretting wear resistance, and corrosion resistance. Under the combined action of corrosion and wear, it exhibits excellent frictional corrosion resistance, can be used stably for a long time, and has excellent practicality.

[0023] In the aforementioned methods for testing friction and corrosion resistance, the CoCrMo alloy exhibits very high tensile strength and yield strength, enabling it to withstand high loads without plastic deformation during friction. The CoCrMo alloy also possesses excellent wear resistance, which is crucial for reducing wear between friction pairs. Its high elastic modulus results in minimal deformation under load, improving the stability of the friction pair system. The high chromium and molybdenum content of the CoCrMo alloy allows it to form a stable passivation film in corrosive environments, further enhancing its corrosion resistance. The simulated body fluid composition closely resembles that of human body fluids, realistically reflecting the material's behavior in actual physiological environments. The simulated body fluid contains various ions (such as Na+). + K + Mg 2+ Ca 2+ These ions (such as...) can undergo complex electrochemical reactions with the surface of metallic materials, simulating the corrosion process under actual physiological conditions. Therefore, the friction corrosion resistance testing method of this invention, by using CoCrMo alloy as the grinding pair material in a micro-motion test device and conducting friction corrosion tests in simulated body fluids, can realistically and effectively evaluate the friction corrosion resistance of titanium alloys in actual use environments.

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their relevant descriptions in this invention can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the micro-arc oxidation electrolysis device used in this invention.

[0027] Figure 2 This is a low-magnification SEM image of the surface of the coating-titanium alloy of the present invention.

[0028] Figure 3 This is a high-magnification SEM image of the surface of the coating-titanium alloy of the present invention.

[0029] Figure 4 This is a high-magnification SEM image of the cross-section of the coated titanium alloy of the present invention.

[0030] Figure 5 This is the EDS surface scan pattern of the coated titanium alloy of the present invention.

[0031] Figure 6 This is the EDS line scan spectrum of the coated titanium alloy of the present invention.

[0032] Figure 7 This is a comparison diagram of the microhardness of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0033] Figure 8 The XRD pattern of the coating-titanium alloy of the present invention is shown.

[0034] Figure 9 This is a comparison chart of the friction coefficients of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0035] Figure 10 This is a comparison chart of the material loss of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0036] Figure 11 This is a comparison diagram of the open-circuit potential of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0037] Figure 12 This is a comparison diagram of the polarization curves of the coating-titanium alloy and the titanium alloy substrate of the present invention. Detailed Implementation

[0038] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0039] The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0040] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0041] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0042] The embodiment of the micro-arc oxidation surface-modified biomedical titanium alloy and its preparation method of the present invention includes the following steps:

[0043] (1) Pretreatment of titanium alloy substrate

[0044] The mass fractions of each element in the titanium alloy substrate are as follows: aluminum 6.05%, vanadium 3.95%, iron 0.11%, carbon 0.014%, oxygen 0.14%, nitrogen 0.006%, hydrogen 0.001%, and titanium 89.729%.

[0045] The titanium alloy substrate has a tensile strength of 860 MPa, a yield strength of 795 MPa, an elongation of 12%, an elastic modulus of 110 GPa, and a Poisson's ratio of 0.3.

[0046] The pretreatment steps for the titanium alloy substrate surface are as follows: First, the substrate is sequentially polished on a polishing machine using 600#, 1000#, 1500#, and 2000# sandpaper. Then, precision polishing is performed using W2.5 diamond polishing paste and a 3000# roughness cloth polishing pad, ultimately achieving a surface roughness Ra ≤ 0.1 μm for the titanium alloy substrate. Before micro-arc oxidation electrolysis, the titanium alloy substrate is ultrasonically cleaned in anhydrous ethanol for two minutes to remove surface impurities, which helps improve coating quality.

[0047] (2) Electrolyte preparation

[0048] A micro-arc oxidation electrolyte was prepared, which was an aqueous solution of sodium titanate, potassium hydroxide, sodium hexametaphosphate, and niobium particles. The concentrations of each component were as follows: sodium titanate 6 g / L, potassium hydroxide 4 g / L, sodium hexametaphosphate 2 g / L, and niobium particles 6 g / L. The particle size of the niobium particles was 40–60 nm.

[0049] (3) Micro-arc oxidation electrolysis reaction

[0050] Figure 1 This is a schematic diagram of the micro-arc oxidation electrolysis device used in this invention. Figure 1 As shown, a titanium alloy substrate was used as the anode, and a stainless steel sheet was used as the cathode. The working distance between the anode and cathode was maintained at 20 mm. 500 ml of micro-arc oxidation electrolyte was placed in the electrolytic cell, and then a micro-arc oxidation electrolysis reaction was carried out to generate a micro-arc oxidation coating on the surface of the titanium alloy substrate. The resulting coating was named "coated titanium alloy". The coated titanium alloy was ultrasonically cleaned in anhydrous ethanol for two minutes, dried, and stored in a sterile drying oven at 25°C.

[0051] The micro-arc oxidation electrolysis reaction is carried out using a constant voltage power supply with a voltage of 350V, a frequency of 500Hz, a duty cycle of 50%, and a reaction time of 30min. The electrolyte temperature is maintained at 30℃ by a circulating pump and a cooling device. A stirrer is provided in the electrolytic cell.

[0052] Figure 2 This is a low-magnification SEM image of the surface of the coating-titanium alloy of the present invention. Figure 3 This is a high-magnification SEM image of the surface of the coating-titanium alloy of the present invention.

[0053] like Figure 2-3 As shown, the micro-arc oxidation coating exhibits a uniform material distribution, numerous porous structures, and a dense surface material. No cracks, delamination, or other damage are observed between the porous structures, indicating good film quality. The measured pore diameters range from 0.5 to 4 μm, and the net distance between adjacent pores ranges from 0.5 to 3 μm.

[0054] Figure 4 This is a high-magnification SEM image of the cross-section of the coated titanium alloy of the present invention.

[0055] like Figure 4 As shown, the micro-arc oxidation coating on the surface of the titanium alloy substrate includes a dense layer and a sparse layer sequentially connected to the titanium alloy substrate. The thickness of the dense layer is 7–9 μm, and the thickness of the sparse layer is 7–9 μm. No obvious cracks were observed in the cross-section of the micro-arc oxidation coating, indicating that the micro-arc oxidation coating and the titanium alloy substrate have good adhesion.

[0056] Figure 5 This is the EDS surface scan pattern of the coated titanium alloy of the present invention.

[0057] like Figure 5 As shown, EDS elemental analysis revealed that the micro-arc oxidation coating contained sodium, oxygen, aluminum, phosphorus, potassium, titanium, and niobium, with mass fractions of 0.91%, 43.92%, 8.64%, 1.14%, 0.45%, 29.62%, and 15.32%, respectively. This indicates that niobium nanoparticles and other electrolytes were successfully integrated into the micro-arc oxidation coating. Simultaneously, the micro-arc oxidation coating underwent a significant oxidation reaction.

[0058] Figure 6 This is the EDS line scan spectrum of the coated titanium alloy of the present invention.

[0059] like Figure 6 As shown, EDS elemental analysis revealed that oxygen, niobium, aluminum, and titanium elements in the micro-arc oxidation coating are uniformly distributed along the depth direction, and the element content shows a clear transition between the micro-arc oxidation coating and the titanium alloy substrate, which can enhance the bonding force between the micro-arc oxidation coating and the titanium alloy substrate.

[0060] Figure 7 This is a comparison diagram of the microhardness of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0061] like Figure 7 As shown, the microhardness of the coating-titanium alloy surface increased by nearly 3 times after introducing a micro-arc oxidation coating on the surface of the titanium alloy substrate.

[0062] Figure 8 The XRD pattern of the coating-titanium alloy of the present invention is shown.

[0063] like Figure 8 As shown, XRD phase analysis revealed that the micro-arc oxidation coating is composed of TiO2, Al2TiO5, NbTi4, and Nb2O5. It can be seen that Nb nanoparticles are oxidized to Nb2O5 during processing.

[0064] An embodiment of the method for testing the friction and corrosion resistance of biomedical titanium alloys modified by micro-arc oxidation of the present invention is to use the micro-motion testing device disclosed in Chinese invention patent application No. CN108760618A to test the friction and corrosion resistance of the coating-titanium alloy and the titanium alloy substrate.

[0065] A copper wire approximately 10 cm long was welded to the back of the coated titanium alloy and the titanium alloy substrate to connect the working electrode for studying its electrochemical properties. The sample was then encapsulated with epoxy resin, leaving only 10 mm exposed. 2 The research surface.

[0066] The grinding pair material is a CoCrMo alloy with a tensile strength of 1507 MPa, a yield strength of 962 MPa, an elongation of 20%, an elastic modulus of 200 GPa, and a Poisson's ratio of 0.3. The mass fractions of each element are as follows: chromium 28.10 wt%, molybdenum 5.90 wt%, nickel 0.88 wt%, iron 0.65 wt%, manganese 0.63 wt%, silicon 0.22 wt%, carbon 0.25 wt%, nitrogen 0.12 wt%, and cobalt 63.25%.

[0067] The open circuit potential before and after the micro-motion test and the polarization curve after the micro-motion test were measured using an electrochemical workstation. The electrochemical test used a three-electrode system: the reference electrode was a saturated Ag / AgCl electrode, the counter electrode was a platinum electrode, and the working electrode was a coated titanium alloy or a titanium alloy substrate.

[0068] The concentrations of each component in the simulated body fluid used are: Na + 142.0mM, K + 5mM, Mg 2+ 1.5mM, Ca 2+ 2.5mM, Cl - The concentration was 147.8 mM, and the concentration of HCO3 was 147.8 mM. - 4.2mM, HPO4 2- 1.0 mM, SO4 2- It is 0.5mM.

[0069] The micro-motion tangential frequency was set to 1 Hz, the number of cycles was 3000, the sampling rate was 40 Hz, the normal load was 45 N, and the displacement amplitude was 45 μm. The pH of the simulated body fluid was maintained at 7.4, and the volume of the corrosion solution required for each experiment was 100 mL.

[0070] Figure 9 This is a comparison chart of the friction coefficients of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0071] like Figure 9 As shown, the micro-arc oxidation coating effectively reduces the friction coefficient of the titanium alloy substrate surface and improves the resistance to fretting wear of the coating-titanium alloy surface.

[0072] Figure 10 This is a comparison chart of the material loss of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0073] like Figure 10 As shown, the introduction of micro-arc oxidation coating can reduce the material loss of the coating-titanium alloy by nearly half compared to the material loss of the titanium alloy substrate.

[0074] Figure 11This is a comparison diagram of the open-circuit potential of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0075] like Figure 11 As shown, before friction begins, the open-circuit potential of the coated titanium alloy is lower than that of the titanium alloy substrate, indicating that the micro-arc oxidation coating reduces the corrosion tendency of the coated titanium alloy surface. After friction begins, the material surface is damaged, and the open-circuit potential decreases. However, the decrease in the open-circuit potential of the coated titanium alloy is less than that of the titanium alloy substrate, indicating that the micro-arc oxidation coating reduces the degree of damage and activity of the coated titanium alloy surface, thereby enhancing its corrosion resistance.

[0076] Figure 12 This is a comparison diagram of the polarization curves of the coating-titanium alloy and the titanium alloy substrate of the present invention.

[0077] like Figure 12 As shown, the corrosion voltage of the coated titanium alloy is -0.243V and the corrosion current is 1.259μA; the corrosion voltage of the titanium alloy substrate is -0.389A and the corrosion current is 14.908μA. It is evident that the introduction of the micro-arc oxidation coating reduces the corrosion current and corrosion voltage, thereby improving the corrosion resistance of the coated titanium alloy surface.

[0078] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A biomedical titanium alloy with micro-arc oxidation surface modification, comprising a titanium alloy substrate, characterized in that: It also includes a micro-arc oxidation coating located on the surface of the titanium alloy substrate; The micro-arc oxidation coating comprises a dense layer and a sparse layer with a porous structure, which are sequentially connected to the titanium alloy substrate. EDS elemental analysis revealed that the micro-arc oxidation coating contains sodium, oxygen, aluminum, phosphorus, potassium, titanium, and niobium. The preparation method of biomedical titanium alloy includes the following steps: A micro-arc oxidation electrolyte is prepared, comprising sodium titanate, potassium hydroxide, sodium hexametaphosphate, and niobium particles. Using a titanium alloy substrate as the anode and a stainless steel sheet as the cathode, a micro-arc oxidation electrolyte is loaded into an electrolytic cell, and then a micro-arc oxidation electrolysis reaction is carried out to generate a micro-arc oxidation coating on the surface of the titanium alloy substrate.

2. The biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 1, characterized in that: The thickness of the dense layer is 7–9 μm, and the thickness of the sparse layer is 7–9 μm.

3. The biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 1, characterized in that: The mass fractions of sodium, oxygen, aluminum, phosphorus, potassium, titanium, and niobium in the micro-arc oxidation coating are 0.91%, 43.92%, 8.64%, 1.14%, 0.45%, 29.62%, and 15.32%, respectively.

4. The biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 1, characterized in that: The micro-arc oxidation coating has a porous structure with pore diameters of 0.5–4 μm and a net distance of 0.5–3 μm between adjacent pores.

5. The biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 1, characterized in that: XRD phase analysis revealed that the micro-arc oxidation coating contains TiO2, Al2TiO5, NbTi4, and Nb2O5.

6. The biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 1, characterized in that: The mass fractions of each element in the titanium alloy substrate are as follows: aluminum 6.05%, vanadium 3.95%, iron 0.11%, carbon 0.014%, oxygen 0.14%, nitrogen 0.006%, hydrogen 0.001%, and titanium 89.729%. The titanium alloy substrate has a tensile strength of 860 MPa, a yield strength of 795 MPa, an elongation of 12%, an elastic modulus of 110 GPa, and a Poisson's ratio of 0.

3. The surface roughness Ra of the titanium alloy substrate is ≤0.1μm.

7. The method for preparing the micro-arc oxidation surface-modified biomedical titanium alloy according to any one of claims 1-6, characterized in that: Includes the following steps: A micro-arc oxidation electrolyte is prepared, comprising sodium titanate, potassium hydroxide, sodium hexametaphosphate, and niobium particles. Using a titanium alloy substrate as the anode and a stainless steel sheet as the cathode, a micro-arc oxidation electrolyte is loaded into an electrolytic cell, and then a micro-arc oxidation electrolysis reaction is carried out to generate a micro-arc oxidation coating on the surface of the titanium alloy substrate.

8. The method for preparing biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 7, characterized in that: The concentrations of each component in the micro-arc oxidation electrolyte are as follows: sodium titanate 5-7 g / L, potassium hydroxide 3-5 g / L, sodium hexametaphosphate 1-3 g / L, and niobium particles 5-7 g / L; the particle size of the niobium particles is 40-60 nm.

9. The method for preparing biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 7, characterized in that: The micro-arc oxidation electrolysis reaction adopts a constant voltage mode with a voltage of 350V, a frequency of 500Hz, a duty cycle of 50%, a reaction time of 30min, and an electrolysis temperature of 30℃.

10. The method for preparing biomedical titanium alloy with micro-arc oxidation surface modification as described in claim 7, characterized in that: It also includes pretreatment of the titanium alloy substrate surface: first, it is polished in sequence on a polishing machine with 600#, 1000#, 1500# and 2000# sandpaper, and then precision polished with W2.5 diamond polishing paste and a cloth polishing disc with a roughness of 3000#.

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