Preparation method of surface biopiezoelectric coating of forced response type titanium alloy

Abstract

The application discloses a preparation method of a forced response type titanium alloy surface biological piezoelectric coating, and specifically comprises the following steps: constructing a titanium dioxide nanotube coating with a seed layer on the surface of the titanium alloy; placing the titanium alloy sample in a barium hydroxide solution to perform a hydrothermal reaction, so as to obtain a zinc oxide seed composite barium titanate nanotube coating; and placing the titanium alloy sample in a reaction solution to perform a hydrothermal reaction, so as to obtain the forced response type titanium alloy surface biological piezoelectric coating. The biological piezoelectric coating prepared by the application has a larger specific surface area and hydrophilicity, and can better promote the proliferation and adhesion of osteoblasts; meanwhile, the zinc oxide nanorod structure is more prone to resonance with low-intensity pulsed ultrasound to produce deformation, so as to generate force on the barium titanate piezoelectric nanotube rooted by the zinc oxide nanorod, and excite the piezoelectric effect of the barium titanate.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy surface treatment technology, specifically relating to a method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface. Background Technology

[0002] Titanium and titanium alloys are widely used as dental and orthopedic implant materials due to their excellent mechanical properties, biocompatibility, and corrosion resistance. However, the bioinertness of titanium and titanium alloys makes it difficult to achieve efficient and rapid osseointegration with surrounding tissues after implantation, posing a risk of implantation failure. To endow titanium alloys with bioactivity, constructing bioactive coatings on the titanium surface is a hot research topic in the field of titanium alloy surface modification. Compared with other bioactive coatings, nanotube structure coatings have attracted widespread attention due to their advantages such as high roughness, large specific surface area, and suitability as drug carriers. However, the bioinertness of titanium dioxide nanotubes limits their clinical application. Studies have shown that human bone exhibits a piezoelectric effect, which can promote osteoblast proliferation and differentiation and accelerate blood circulation. The resulting electrical signals play a crucial role in osteoogenesis, osseointegration, and fracture healing. Constructing bio-piezoelectric nanotube coatings on the surface of titanium alloys can endow them with a piezoelectric effect, which is highly valuable for the formation of rapid osseointegration. Since the piezoelectric effect is a force-electric conversion effect, the activation of the piezoelectric effect of the coating requires the intervention of mechanical force. In particular, when the piezoelectric coating on the surface of titanium alloy is implanted into the body, how to activate the piezoelectric effect of the coating under the premise that the patient cannot exercise a lot in the early stage of recovery is an urgent problem to be solved.

[0003] Chinese patent "A Method for Preparing a Bio-piezoelectric Composite Coating on the Surface of a Medical Titanium Alloy" (Application No.: 201711329754.1, Publication No.: CN108079381A, Publication Date: 2018-05-29) discloses a method for preparing a bio-piezoelectric composite coating on the surface of a medical titanium alloy, forming a composite coating with bio-piezoelectric properties on the surface of the medical titanium alloy. Although the prepared titanium alloy has piezoelectric properties, the problem of activating the piezoelectric effect remains unsolved. Chinese patent "A Barium Copper Titanate Piezoelectric Ceramic Coating, Its Preparation Method and Use" (Application No.: 202310330780.5, Publication No.: CN116043205A, Publication Date: 2023-05-02) discloses a barium copper titanate piezoelectric ceramic coating, its preparation method and use. The release rate and concentration of copper ions in the barium copper titanate piezoelectric ceramic coating are controllable, preventing biotoxicity, and the piezoelectric coefficient of the ceramic coating is consistent with that of human wet bone. However, the activation of the coating depends on the movement of the human body. Chinese patent "A Method for Preparing a Bio-piezoelectric Composite Gradient Coating on the Surface of Titanium or Titanium Alloy" (Application No.: 201910252703.6, Publication No.: CN1109939909A, Publication Date: 2019-06-28) discloses a method for preparing a bio-piezoelectric composite gradient coating on the surface of titanium or titanium alloy, solving the problems of low piezoelectricity, poor interfacial bonding strength, and low bioactivity in existing bio-piezoelectric coatings of titanium and its alloys. However, the problem of activating the piezoelectric effect of the coating remains unsolved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface, thereby solving the problem that the piezoelectric effect of bio-piezoelectric coatings on titanium alloy surfaces is difficult to excite in the prior art.

[0005] The technical solution adopted in this invention is a method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface, which is implemented according to the following steps:

[0006] Step 1: Coat the titanium alloy surface with a titanium dioxide nanotube coating containing a seed layer;

[0007] Step 2: Place the titanium alloy sample obtained in Step 1 in a barium hydroxide solution for hydrothermal reaction to obtain a barium titanate nanotube coating with zinc oxide seed crystals.

[0008] Step 3: Place the titanium alloy sample prepared in step 2 into the reaction solution for hydrothermal reaction to obtain a bio-piezoelectric coating on the surface of the stress-responsive titanium alloy.

[0009] The invention is further characterized in that,

[0010] Step 1 specifically involves:

[0011] Step 1.1: Degrease and polish the surface of the titanium alloy, rinse it with deionized water, and then perform chemical polishing in a chemical polishing solution to obtain the treated titanium alloy.

[0012] Step 1.2: Mix ethylene glycol, ammonium fluoride, and deionized water, stir until homogeneous to obtain an electrolyte. Use the treated titanium alloy as the anode and a platinum sheet as the cathode. Adjust the distance between the anode and cathode, the anodic oxidation current, and the anodic oxidation time. Perform two anodic oxidation treatments on the titanium alloy in the electrolyte. Afterward, clean the titanium alloy sample and perform annealing treatment to form a titanium dioxide nanotube array coating on the surface of the titanium alloy.

[0013] Step 1.3: Vacuum immerse the titanium alloy sample obtained in step 1.2 in the seed precursor solution, repeat the immersion 2 to 3 times, take out the titanium alloy sample, gently wash the surface, and perform heat treatment to coat the titanium dioxide nanotube coating with the seed layer on the surface of the titanium alloy.

[0014] In step 1.2, during the first anodizing treatment, the mass ratio of ammonium fluoride, deionized water, and ethylene glycol in the electrolyte is 1:1 to 10:150 to 250; during the second anodizing treatment, the mass ratio of ammonium fluoride, deionized water, and ethylene glycol in the electrolyte is 1:5 to 20:500 to 700; the distance between the anode and cathode is 15 to 25 mm, the anodizing current is 30 to 100 mA, and the anodizing time is 20 to 80 min.

[0015] In step 1.2, the annealing temperature is 300-500℃ and the annealing time is 1-5h.

[0016] In step 1.3, the seed precursor solution is prepared by mixing zinc acetate, ethanolamine and anhydrous ethanol solvent; the vacuum soaking time is 20 to 40 minutes each time.

[0017] In step 2, the concentration of barium hydroxide solution is 0.01–0.3 mol / L; the hydrothermal reaction conditions are: hydrothermal temperature of 180–220℃ and hydrothermal time of 1–3 h.

[0018] In step 3, the reaction solution is composed of zinc nitrate, hexamethylenetetramine, and water; the concentration of the reaction solution is 0.1-1 mmol / L, and the molar ratio of zinc nitrate to hexamethylenetetramine is 1:1.

[0019] It consists of an aqueous solution of zinc nitrate and an aqueous solution of hexamethylenetetramine; the concentrations of both the aqueous solution of zinc nitrate and the aqueous solution of hexamethylenetetramine are 0.1–1 mmol / L.

[0020] In step 3, the hydrothermal reaction conditions are: hydrothermal temperature of 80-90℃ and hydrothermal time of 20-40 min.

[0021] The beneficial effects of this invention are as follows: a titanium dioxide nanotube coating is prepared on the surface of a titanium alloy using anodizing technology; a seed layer is then formed on the inner wall of the titanium dioxide nanotubes using a negative pressure method; the nanotube array is transformed into a seed-composite barium titanate nanotube array using a hydrothermal reaction method; and zinc oxide nanorods are prepared inside the composite seed nanotubes using a hydrothermal method, ultimately forming a piezoelectric nanotube structure coating with zinc oxide nanorods as forced oscillators. Compared with coatings of other structures, this forced-response bio-piezoelectric coating on the titanium alloy surface has a larger specific surface area and hydrophilicity, which can better promote osteoblast proliferation and adhesion; at the same time, the zinc oxide nanorod structure is more likely to resonate with low-intensity pulsed ultrasound and deform, thereby generating a force on the barium titanate piezoelectric nanotubes rooted in the zinc oxide nanorods, stimulating the piezoelectric effect of barium titanate, and forming a synergistic effect of the piezoelectric effects of zinc oxide and barium titanate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the bio-piezoelectric coating on the surface of the stress-responsive titanium alloy of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] The method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface according to the present invention is implemented according to the following steps:

[0025] Step 1: Coating the titanium alloy surface with a titanium dioxide nanotube coating containing a seed layer; specifically:

[0026] Step 1.1: Degrease and polish the surface of the titanium alloy, rinse it with deionized water, and then perform chemical polishing in a chemical polishing solution to obtain the treated titanium alloy.

[0027] Titanium alloys can be titanium sheets, titanium nails, or titanium alloy supports.

[0028] Step 1.2: Mix ethylene glycol, ammonium fluoride, and deionized water, stir until homogeneous to obtain an electrolyte. Use the treated titanium alloy as the anode and a platinum sheet as the cathode. Adjust the distance between the anode and cathode, the anodic oxidation current, and the anodic oxidation time. Perform two anodic oxidation treatments on the titanium alloy in the electrolyte. Afterward, clean the titanium alloy sample and perform annealing treatment to form a titanium dioxide nanotube array coating on the surface of the titanium alloy.

[0029] During the first anodizing treatment, the mass ratio of ammonium fluoride, deionized water and ethylene glycol in the electrolyte is 1:1 to 10:150 to 250; during the second anodizing treatment, the mass ratio of ammonium fluoride, deionized water and ethylene glycol in the electrolyte is 1:5 to 20:500 to 700.

[0030] The distance between the anode and cathode is 15–25 mm, the anodizing current is 30–100 mA, and the anodizing time is 20–80 min; the annealing temperature is 300–500 °C, and the annealing time is 1–5 h.

[0031] Step 1.3: Vacuum immerse the titanium alloy sample obtained in step 1.2 in the seed precursor solution, repeat the immersion 2 to 3 times, take out the titanium alloy sample, gently wash the surface, and heat treat at 500℃ for 60 minutes to coat the titanium alloy surface with a titanium dioxide nanotube coating with a seed layer.

[0032] The seed precursor solution is a mixture of zinc acetate, ethanolamine and anhydrous ethanol solvent;

[0033] The molar ratio of zinc acetate to ethanolamine was 1:1; the concentration of the seed precursor solution was 0.025 mol / L; and the vacuum soaking time was 20–40 min each time.

[0034] Step 2: Prepare a zinc oxide seed composite barium titanate nanotube coating on the surface of the titanium alloy obtained in Step 1; specifically:

[0035] The titanium alloy sample obtained in step 1 was placed in a barium hydroxide solution for hydrothermal reaction to obtain a barium titanate nanotube coating with zinc oxide seed crystals.

[0036] The concentration of barium hydroxide solution is 0.01–0.3 mol / L; the hydrothermal reaction conditions are: hydrothermal temperature 180–220℃, hydrothermal time 1–3 h.

[0037] Step 3: Prepare a stress-responsive bio-piezoelectric coating on the titanium surface;

[0038] The titanium alloy sample prepared in step 2 is placed in the reaction solution for hydrothermal reaction to obtain a bio-piezoelectric coating on the surface of the stress-responsive titanium alloy.

[0039] The reaction solution consists of zinc nitrate, hexamethylenetetramine, and water; the concentration of the reaction solution is 0.1-1 mmol / L, and the molar ratio of zinc nitrate to hexamethylenetetramine is 1:1.

[0040] The hydrothermal reaction conditions are: hydrothermal temperature of 80-90℃ and hydrothermal time of 20-40 min.

[0041] The method for preparing the forced-response type bio-piezoelectric coating on the surface of titanium alloy of the present invention draws on the resonance effect (when one of two objects with the same vibration frequency vibrates, the other vibrates under pressure). By combining impregnation and hydrothermal treatment, a "forced oscillator" is cleverly constructed inside the piezoelectric nanotube to form a "forced-response type" structure. Combined with the low-intensity pulsed ultrasound physiotherapy technology commonly used in clinical practice, the "forced-response type" structure coating can respond to low-intensity pulsed ultrasound and produce a good piezoelectric response.

[0042] Figure 1 This is a schematic diagram of the forced-response type bio-piezoelectric coating structure on the surface of titanium alloy according to the present invention; by Figure 1 It can be seen that the forced-response structure prepared on the surface of titanium alloy by anodizing combined with hydrothermal method mainly consists of zinc oxide nanorods with piezoelectric effect and barium titanate nanotubes. Barium titanate can be generated in situ from titanium dioxide nanotubes, which can both retain the nanotube structure and ensure a strong bond between the two. Zinc oxide can be generated by wet reaction, especially forming nanorod structures in the narrow area of ​​nanotubes. In the preparation process, zinc oxide seeds are first formed on the inner wall of titanium dioxide nanotubes. After the first hydrothermal reaction, a composite layer of zinc oxide seeds and barium titanate is formed on the inner wall of the nanotubes. After the second hydrothermal reaction, the seeds gradually grow into zinc oxide nanorods, and finally a special structure is formed in which zinc oxide nanorods are rooted at the interface between barium titanate and titanium dioxide. This special structure can ensure the bonding force between zinc oxide nanorods and the matrix, so that they vibrate under the action of low-intensity pulsed ultrasound without falling off, and can exert a forming force on barium titanate, stimulating the piezoelectric effect of barium titanate.

[0043] Example 1

[0044] The method for preparing the stress-responsive bio-piezoelectric coating on the surface of a titanium alloy according to the present invention is as follows:

[0045] The titanium sheet surface was degreased and polished smooth, then rinsed with deionized water and chemically polished in a chemical polishing solution. Ethylene glycol, ammonium fluoride, and deionized water were mixed in mass ratios of 1:10:150 and 1:5:700, and stirred thoroughly to obtain an electrolyte. Using the treated titanium sheet as the anode and a platinum sheet as the cathode, the distance between the anode and cathode was adjusted to 15 mm. The anodic oxidation current was 100 mA, and the first anodic oxidation time was 80 min. A second anodic oxidation treatment was performed on the titanium alloy in the electrolyte for 20 min. Afterward, the titanium sheet was cleaned and annealed at 300℃ for 5 h. The treated sample was then vacuum-immersed in a 0.025 mol / L solution of zinc acetate and ethanolamine in a 1:1 molar ratio in anhydrous ethanol for 20 min, repeated three times. After gently washing the surface, it was heat-treated at 500℃ for 60 min to obtain a titanium dioxide nanotube coating with a seed layer. The sample was placed in a 0.01 mol / L barium hydroxide solution and subjected to a hydrothermal reaction at 220℃ for 3 h. The sample was then subjected to a second hydrothermal reaction using a 0.1 mmol / L aqueous solution of zinc nitrate and hexamethylenetetramine at 90℃ for 20 min. This second hydrothermal reaction resulted in the preparation of a stress-responsive bio-piezoelectric coating on the titanium surface.

[0046] Example 2

[0047] The method for preparing the stress-responsive bio-piezoelectric coating on the surface of a titanium alloy according to the present invention is as follows:

[0048] The surface of the titanium nails was degreased and polished smooth, then rinsed with deionized water and chemically polished in a chemical polishing solution. Ethylene glycol, ammonium fluoride, and deionized water were mixed in mass ratios of 1:5:200 and 1:10:600, and stirred thoroughly to obtain an electrolyte. Using the treated titanium sheet as the anode and a platinum sheet as the cathode, the distance between the anode and cathode was adjusted to 20 mm. The anodic oxidation current was 50 mA, and the first anodic oxidation time was 70 min. A second anodic oxidation treatment was then performed on the titanium alloy in the electrolyte for 40 min. Afterward, the titanium sheet was cleaned and annealed at 400℃ for 3 h. The treated sample was then vacuum-immersed in a 0.025 mol / L solution of zinc acetate and ethanolamine in a 1:1 molar ratio in anhydrous ethanol for 30 min, repeated twice. After gently washing the surface, it was heat-treated at 500℃ for 60 min to obtain a titanium dioxide nanotube coating with a seed layer. The sample was placed in a 0.1 mol / L barium hydroxide solution and subjected to a hydrothermal reaction at 200℃ for 2 h. The sample was then subjected to a second hydrothermal reaction using a 0.5 mmol / L zinc nitrate and hexamethylenetetramine aqueous solution at 85℃ for 30 min. This second hydrothermal reaction resulted in the preparation of a stress-responsive bio-piezoelectric coating on the surface of the titanium nail.

[0049] Example 3

[0050] The method for preparing the stress-responsive bio-piezoelectric coating on the surface of a titanium alloy according to the present invention is as follows:

[0051] The surface of the titanium alloy support was degreased and polished smooth, then rinsed with deionized water and chemically polished in a chemical polishing solution. Ethylene glycol, ammonium fluoride, and deionized water were mixed in mass ratios of 1:1:250 and 1:20:500, respectively, and stirred thoroughly to obtain an electrolyte. Using the treated titanium sheet as the anode and a platinum sheet as the cathode, the distance between the anode and cathode was adjusted to 25 mm. The anodizing current was 30 mA, and the first anodizing time was 60 min. A second anodizing treatment was then performed on the titanium alloy in the electrolyte for 30 min. Afterward, the titanium sheet was cleaned and annealed at 500℃ for 1 h. The treated sample was then vacuum-immersed in a 0.025 mol / L solution of zinc acetate and ethanolamine in a 1:1 molar ratio in anhydrous ethanol for 20 min, repeated twice. After gently washing the surface, it was heat-treated at 500℃ for 60 min to obtain a titanium dioxide nanotube coating with a seed layer. The sample was placed in a 0.3 mol / L barium hydroxide solution and subjected to a hydrothermal reaction at 180°C for 1 h. The sample was then subjected to a second hydrothermal reaction using a 1.0 mmol / L zinc nitrate and hexamethylenetetramine aqueous solution at 80°C for 40 min. This second hydrothermal reaction resulted in the formation of a bio-piezoelectric coating on the surface of the stress-responsive titanium alloy scaffold.

[0052] Example 4

[0053] The method for preparing the stress-responsive bio-piezoelectric coating on the surface of a titanium alloy according to the present invention is as follows:

[0054] The surface of the titanium alloy support was degreased and polished smooth, then rinsed with deionized water and chemically polished in a chemical polishing solution. Ethylene glycol, ammonium fluoride, and deionized water were mixed in mass ratios of 1:8:220 and 1:15:550, respectively, and stirred thoroughly to obtain an electrolyte. Using the treated titanium sheet as the anode and a platinum sheet as the cathode, the distance between the anode and cathode was adjusted to 20 mm. The anodizing current was 80 mA, and the first anodizing time was 50 min. A second anodizing treatment was then performed on the titanium alloy in the electrolyte for 40 min. Afterward, the titanium sheet was cleaned and annealed at 450℃ for 3 h. The treated sample was then vacuum-immersed in a 0.025 mol / L solution of zinc acetate and ethanolamine in a 1:1 molar ratio in anhydrous ethanol for 25 min, repeated twice. After gently washing the surface, it was heat-treated at 500℃ for 60 min to obtain a titanium dioxide nanotube coating with a seed layer. The sample was placed in a 0.05 mol / L barium hydroxide solution and subjected to a hydrothermal reaction at 190 °C for 3 h. The sample was then subjected to a second hydrothermal reaction using a 1.0 mmol / L zinc nitrate hexamethylenetetramine aqueous solution at 80 °C for 40 min. This second hydrothermal reaction resulted in the formation of a bio-piezoelectric coating on the surface of the stress-responsive titanium alloy scaffold.

[0055] control group

[0056] The coating preparation process is as follows: The surface of the titanium sheet is degreased and polished smooth, rinsed with deionized water, and then chemically polished in a chemical polishing solution. Ethylene glycol, ammonium fluoride, and deionized water are mixed at mass ratios of 1:10:150 and 1:5:700, and stirred evenly to obtain an electrolyte. The treated titanium sheet is used as the anode, and a platinum sheet as the cathode. The distance between the anode and cathode is adjusted to 15 mm, the anodic oxidation current is 100 mA, and the first anodic oxidation time is 80 min. A second anodic oxidation treatment is performed on the titanium alloy in the electrolyte for 20 min. Afterward, the titanium sheet is cleaned and annealed at 300℃ for 5 h. The sample is placed in a 0.01 mol / L barium hydroxide solution and subjected to a hydrothermal reaction at 220℃ for 3 h to prepare the coating for the control group.

[0057] The forced-response titanium alloy bio-piezoelectric coatings prepared in Examples 1-4 of this invention were polarized and immersed in simulated body fluid for 7 days. During this period, low-intensity pulsed ultrasound was applied to the coatings. After immersion, the mass change of the coatings was measured, and the results are shown in Table 1. As can be seen from the table, the mass increase of the coatings in Examples 1-4 after immersion was much greater than that of the control group. This is because after the application of low-intensity pulsed ultrasound, the forced-response coating structure of Examples 1-4 can better respond to its effect and stimulate the piezoelectric effect of the coating. Furthermore, the piezoelectric effect is conducive to the deposition of calcium and phosphorus ions in simulated body fluid on the coating surface, which ultimately leads to a much greater mass increase of the coating than that of the control group.

[0058] Table 1. Mass changes of the coatings in Examples 1-4 after polarization and immersion in simulated body fluid for 7 days.

[0059] Increase in mass (mg) 0.51 0.93 0.86 1.03 0.95

[0060] This invention employs anodizing technology combined with hydrothermal reaction to prepare a seed-coated titanium dioxide nanotube coating on the surface of a titanium alloy. The nanotubes are then converted into seed-composite barium titanate nanotubes via hydrothermal method. Furthermore, a forced oscillator of zinc oxide nanorods is prepared within the nanotube coating, thereby creating a forced-response bio-piezoelectric coating on the titanium alloy surface. This solves the problem of the difficulty in activating the piezoelectric effect in bio-piezoelectric coatings on titanium alloy surfaces prepared by existing technologies.

Claims

1. A method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface, characterized in that, The specific steps are as follows: Step 1: Coating the titanium alloy surface with a titanium dioxide nanotube coating containing a seed layer; specifically: Step 1.1: Degrease and polish the surface of the titanium alloy, rinse it with deionized water, and then perform chemical polishing in a chemical polishing solution to obtain the treated titanium alloy. Step 1.2: Mix ethylene glycol, ammonium fluoride, and deionized water, stir until homogeneous to obtain an electrolyte. Use the treated titanium alloy as the anode and a platinum sheet as the cathode. Adjust the distance between the anode and cathode, the anodic oxidation current, and the anodic oxidation time. Perform two anodic oxidation treatments on the titanium alloy in the electrolyte. Afterward, clean the titanium alloy sample and perform annealing treatment to form a titanium dioxide nanotube array coating on the surface of the titanium alloy. Step 1.3: Vacuum immerse the titanium alloy sample obtained in step 1.2 in the seed precursor solution, repeat the immersion 2-3 times, take out the titanium alloy sample, gently wash the surface, and perform heat treatment to coat the titanium dioxide nanotube coating with the seed layer on the surface of the titanium alloy. Step 2: Place the titanium alloy sample obtained in Step 1 in a barium hydroxide solution for hydrothermal reaction to obtain a barium titanate nanotube coating with zinc oxide seed crystals. In step 2, the concentration of barium hydroxide solution is 0.01~0.3mol / L; the hydrothermal reaction conditions are: hydrothermal temperature 180~220℃, hydrothermal time 1~3h; Step 3: Place the titanium alloy sample prepared in step 2 into the reaction solution for hydrothermal reaction to obtain a bio-piezoelectric coating on the surface of the stress-responsive titanium alloy. In step 3, the reaction solution is composed of zinc nitrate, hexamethylenetetramine, and water; the concentration of the reaction solution is 0.1-1 mmol / L, and the molar ratio of zinc nitrate to hexamethylenetetramine is 1:

1. In step 3, the hydrothermal reaction conditions are: hydrothermal temperature of 80~90℃ and hydrothermal time of 20~40min.

2. The method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface as described in claim 1, characterized in that, In step 1.2, during the first anodizing treatment, the mass ratio of ammonium fluoride, deionized water, and ethylene glycol in the electrolyte is 1:1~10:150~250; during the second anodizing treatment, the mass ratio of ammonium fluoride, deionized water, and ethylene glycol in the electrolyte is 1:5~20:500~700; the distance between the anode and cathode is 15~25mm, the anodizing current is 30~100mA, and the anodizing time is 20~80min.

3. The method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface as described in claim 1, characterized in that, In step 1.2, the annealing temperature is 300~500℃ and the annealing time is 1~5h.

4. The method for preparing a stress-responsive bio-piezoelectric coating on a titanium alloy surface as described in claim 1, characterized in that, In step 1.3, the seed precursor solution is composed of zinc acetate, ethanolamine and anhydrous ethanol solvent; the vacuum soaking time is 20-40 min each time.

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