Antibacterial titanium alloy composite coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of metal surface treatment, and discloses an antibacterial titanium alloy composite coating and a preparation method and application thereof. The composite coating is located on the titanium alloy matrix and comprises an inner porous titanium dioxide layer, a middle silver-loaded functional layer and an outer COS-HNTs composite layer from inside to outside. According to the antibacterial titanium alloy composite coating, efficient sterilization is achieved through cooperation of multiple antibacterial mechanisms, explosive release of an antibacterial agent is avoided through a multi-layer structure, and the lasting antibacterial effect is achieved. Mg < 2 + > and Sr < 2 + > of the middle silver-loaded functional layer and a calcium element and a phosphorus element of the inner porous titanium dioxide layer are both beneficial to osteoblast proliferation and differentiation; and the outer layer of the COS-HNTs composite layer has good biocompatibility. Meanwhile, the composite coating has excellent coating bonding strength and durability and can effectively block corrosive media. The preparation method has good process adaptability, and process parameters can be flexibly adjusted according to different application scene requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal surface treatment, and particularly relates to an antibacterial titanium alloy composite coating and a preparation method and application thereof. BACKGROUND

[0002] Currently, the methods for realizing the antibacterial performance of titanium alloy mainly include surface coating and antibacterial alloying methods, but the existing technology has many challenges: (1) the balance between the biocompatibility and antibacterial performance of the antibacterial agent is difficult, for example, although silver ions or nano-silver particles have a spectrum of antibacterial performance, the silver ions or nano-silver particles have potential biological toxicity, and the free state is easy to be phagocytosed by normal cells to cause toxicity; (2) the insufficient bonding strength of the coating and the substrate easily leads to peeling and failure; (3) the antibacterial life and the implant life are poorly matched, and early burst release or late failure occurs; (4) the uniformity of the coating of a complex-shaped implant is difficult to guarantee; (5) the effect of a single antibacterial mechanism is limited; and (5) some processes, such as electroplating process, have the risk of hydrogen embrittlement or high cost and complex process. SUMMARY

[0003] In view of the above problems existing in the prior art, the purpose of the present application is to provide an antibacterial titanium alloy composite coating and a preparation method and application thereof.

[0004] To solve the above problems, the present application provides the following technical scheme: In a first aspect, the present application provides an antibacterial titanium alloy composite coating, which is located on a titanium alloy substrate and comprises, from inside to outside: an inner porous titanium dioxide layer, an intermediate silver-loaded functional layer and an outer COS-HNTs composite layer.

[0005] In an embodiment of the present application, the intermediate silver-loaded functional layer is a silver-loaded magnesium titanate layer or a silver-loaded strontium titanate layer.

[0006] In an embodiment of the present application, the thickness of the inner porous titanium dioxide layer is 5-20 μm.

[0007] In an embodiment of the present application, the porosity of the inner porous titanium dioxide layer is 20-40%.

[0008] In an embodiment of the present application, the average pore size of the inner porous titanium dioxide layer is 50-300 nm.

[0009] In an embodiment of the present application, the thickness of the intermediate silver-loaded functional layer is 1-5 μm.

[0010] In an embodiment of the present application, the thickness of the outer COS-HNTs composite layer is 0.5-3 μm.

[0011] In an embodiment of the present application, the inner porous titania layer is a porous titania layer containing calcium and phosphorus elements to promote bone integration.

[0012] In an embodiment of the present application, the silver in the intermediate silver-loaded functional layer is selected from silver oxide nanoparticles.

[0013] In an embodiment of the present application, the silver in the intermediate silver-loaded functional layer is in the form of Ag2O and AgO nanoparticles.

[0014] In an embodiment of the present application, the silver oxide nanoparticles have a particle size of 10-100 nm.

[0015] In an embodiment of the present application, the content of the silver oxide nanoparticles in the intermediate silver-loaded functional layer is 0.5-5 wt.%.

[0016] In an embodiment of the present application, the HNTs in the outer COS-HNTs composite layer are loaded with iodine ions or silver ions.

[0017] In a second aspect, the present application provides a method for preparing an antibacterial titanium alloy composite coating, comprising the following steps: S1, pretreating the titanium alloy substrate; S2, using the pretreated titanium alloy as an anode and placing it in an electrolyte to form a porous titania layer containing calcium and phosphorus elements on the surface of the titanium alloy by a micro-arc oxidation process; the oxidized workpiece is ultrasonically cleaned with deionized water and dried; S3, immersing the workpiece obtained in step S2 in an alkaline sodium compound solution to form a sodium titanate layer on the surface; after washing with water, immersing the workpiece in a hydrochloric acid solution and a magnesium nitrate or strontium nitrate solution for ion exchange to form a magnesium titanate or strontium titanate pre-oxidation layer; S4, after washing with water and drying, immersing the workpiece in an electrolyte containing EDTA-Ag complex for pulse electrodeposition; performing heat treatment in an air atmosphere to obtain an intermediate silver-loaded functional layer; S5, immersing the workpiece in a COS-HNTs precursor solution, then drying and curing at room temperature to form a cross-linked composite layer; immersing the workpiece in a povidone iodine solution for soaking, and drying at room temperature to load iodine elements in the HNTs tubes; washing the coating surface with deionized water and then vacuum drying.

[0018] In an embodiment of the present application, in step S1, the pretreatment includes removing oil from the titanium alloy substrate, primary water washing, acid pickling activation, and secondary water washing, specifically as follows: immersing the titanium alloy substrate in an acetone solution at 20-30℃ for 10-15 minutes to remove oil stains on the surface of the titanium alloy substrate; Clean twice with deionized water using ultrasonic cleaning, 3 minutes each time; A mixed solution of 8-15 wt.% nitric acid and 3-5 wt.% hydrofluoric acid is used to soak the surface at 20-30℃ for 5-10 minutes to remove the oxide scale and activate the surface. Rinse with deionized water with a resistivity ≥15 MΩ·cm to ensure that there is no acid residue on the surface of the titanium alloy substrate and quickly proceed to step S2 to prevent secondary oxidation.

[0019] In one embodiment of this application, in step S2, the micro-arc oxidation electrolyte comprises 0.15-0.25 mol / L Ca(CH3COO)2·H2O and 0.01-0.03 mol / L C3H7Na2O6P·5H2O.

[0020] In one embodiment of this application, in step S2, the pH value of the micro-arc oxidation electrolyte is adjusted to 8.5-9.5 using NaOH.

[0021] In one embodiment of this application, the parameters of the micro-arc oxidation process in step S2 are: voltage of 340-380V, frequency of 400-600 Hz, duty cycle of 25%, and time of 8-12 minutes.

[0022] In one embodiment of this application, in step S2, the temperature of the micro-arc oxidation electrolyte is 20-30°C.

[0023] In one embodiment of this application, in step S3, the alkaline sodium compound solution is a NaOH solution.

[0024] In one embodiment of this application, in step S3, the concentration of the NaOH solution is 3-8 mol / L.

[0025] In one embodiment of this application, the processing temperature in step S3 is 60-90°C.

[0026] In one embodiment of this application, the processing time in step S3 is 18-36 hours.

[0027] In one embodiment of this application, in step S3, the concentration of the hydrochloric acid solution is 0.05-0.1 mol / L.

[0028] In one embodiment of this application, in step S3, the concentration of the magnesium nitrate solution is 0.05-0.1 mol / L.

[0029] In one embodiment of this application, in step S3, the concentration of the strontium nitrate solution is 0.05-0.1 mol / L.

[0030] In one embodiment of this application, the ion exchange time in step S3 is 30-60 minutes.

[0031] In one embodiment of this application, in step S4, the electrolyte containing the EDTA-Ag complex is a solution of 0.05 mol / L EDTA-2Na and 0.02 mol / L AgNO3.

[0032] In one embodiment of this application, in step S4, the pH of the electrolyte containing the EDTA-Ag complex is adjusted to 8.0.

[0033] In one embodiment of this application, in step S4, the current density of pulse electrodeposition is 0.5-2 A / dm³. 2 The pulse electrodeposition frequency is 50-200 Hz; the duty cycle is 20-50%; and the pulse electrodeposition time is 5-10 minutes.

[0034] In one embodiment of this application, step S4 employs a dual-pulse power supply: alternating positive pulses (peak current density 1.5 A / dm², ton = 5 ms, toff = 15 ms) and negative pulses (peak current density -0.5 A / dm², ton = 2 ms, toff = 10 ms) for a total duration of 8 minutes. This mode effectively avoids concentration polarization, resulting in a uniformly distributed silver deposition layer.

[0035] In one embodiment of this application, in step S4, the heat treatment temperature is 350-400°C.

[0036] In one embodiment of this application, the heat treatment temperature in step S4 is 380°C.

[0037] In one embodiment of this application, the heat treatment time in step S4 is 2-4 hours.

[0038] In one embodiment of this application, the heat treatment time in step S4 is 3 hours.

[0039] In one embodiment of this application, in step S4, the metallic silver particles are transformed into Ag2O and AgO nanoparticles by heat treatment, which are stably present in the intermediate silver-loaded functional layer.

[0040] In one embodiment of this application, the preparation method of the COS-HNTs precursor solution in step S5 is as follows: 1-20 wt.% of HNTs are ultrasonically dispersed in an aqueous solution of 1-3 wt.% acetic acid for 1 hour, 0.5-5 wt.% of COS is added, and the mixture is stirred until completely dissolved. Finally, Al is added. 3+ The crosslinking agent is stirred at 50-60℃ for 2-4 hours.

[0041] In one embodiment of this application, Al 3+ The crosslinking agent is selected from AlCl3 and Al2(SO4)3.

[0042] In one embodiment of this application, Al 3+ The concentration of the crosslinking agent is 3-10 wt.%.

[0043] In one embodiment of this application, in step S5, the concentration of the povidone-iodine solution is 1% (w / v).

[0044] In one embodiment of this application, the soaking time in step S5 is 1 minute.

[0045] In one embodiment of this application, in step S5, the temperature of vacuum drying is 60-80°C.

[0046] Thirdly, this application provides a titanium-based material, including a titanium alloy matrix and an antibacterial titanium alloy composite coating.

[0047] Fourthly, titanium-based materials can be used to prepare medical titanium alloy implants, which are suitable for orthopedics, dentistry, and other fields.

[0048] Compared with the prior art, the present invention has the following beneficial effects: (1) The antibacterial titanium alloy composite coating provided in this application has a synergistic and efficient bactericidal effect through multiple antibacterial mechanisms; the middle silver-loaded functional layer directly destroys the bacterial cell membrane through the oxidation of Ag2O and AgO, and has contact sterilization without the dissolution of metal ions. Furthermore, by controlling the particle size and content of silver oxide nanoparticles, cytotoxicity is avoided; the outer COS-HNTs composite layer has a slow-release bactericidal function. COS itself has antibacterial properties, and the HNTs lumen can load and slowly release iodine ions or silver ions to achieve long-term antibacterial effect; the inner porous titanium dioxide layer has photocatalytic activity and can generate active oxygen for sterilization under specific light conditions.

[0049] (2) The antibacterial titanium alloy composite coating provided in this application has long-lasting antibacterial stability. Through the multi-layer structure, the burst release of antibacterial agents is avoided, thus achieving a lasting antibacterial effect.

[0050] (3) The antibacterial titanium alloy composite coating provided in this application has excellent biocompatibility and bone integration; the Mg in the intermediate silver-loaded functional layer 2+ 、Sr 2+ The calcium and phosphorus elements in the inner porous titanium dioxide layer are beneficial to osteoblast proliferation and differentiation; the outer COS-HNTs composite layer has good biocompatibility.

[0051] (4) The antibacterial titanium alloy composite coating provided in this application has excellent coating bonding strength and durability, and can effectively block corrosive media.

[0052] (5) The method for preparing the antibacterial titanium alloy composite coating provided in this application has good process adaptability and the process parameters can be flexibly adjusted according to different application scenarios. Detailed Implementation

[0053] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. Example 1

[0055] This embodiment provides a method for preparing an antibacterial titanium alloy composite coating: Pretreatment of the titanium alloy substrate: Immerse the titanium alloy substrate in acetone solution at 25°C for 15 minutes to remove oil stains from the surface. Ultrasonically clean twice with deionized water for 3 minutes each time, ensuring no acetone solution residue remains. Immerse in a mixed solution of 15 wt.% nitric acid and 5 wt.% hydrofluoric acid at 25°C for 10 minutes to remove oxide scale and activate the surface. Rinse with deionized water with a resistivity ≥15 MΩ·cm to ensure no acid residue remains on the surface and allow for rapid entry into the next process, preventing secondary oxidation.

[0056] Constructing an inner porous titanium dioxide layer: The pretreated titanium alloy was used as the anode and placed in a micro-arc oxidation electrolyte. A porous titanium dioxide layer containing calcium and phosphorus was formed on the surface of the titanium alloy using a micro-arc oxidation process. After oxidation, the workpiece was ultrasonically cleaned with deionized water and dried. The micro-arc oxidation electrolyte formulation was: 0.20 mol / L Ca(CH3COO)2·H2O and 0.02 mol / L C3H7Na2O6P·5H2O, with the pH adjusted to 9.0 using NaOH. The micro-arc oxidation process parameters were: initial voltage of 100 V, increased to 360 V at a rate of 10 V / s, frequency of 500 Hz, duty cycle of 25%, and treatment time of 10 minutes. A circulating cooling system was used throughout the process to maintain the electrolyte temperature at 25℃.

[0057] Construction of the intermediate silver-loaded functional layer: The workpiece was further immersed in a 4.5 mol / L NaOH solution and treated at 75°C for 24 hours to form a sodium titanate layer on the surface. After rinsing with water, the workpiece was sequentially immersed in a 0.075 mol / L hydrochloric acid solution and a 0.075 mol / L magnesium nitrate solution for 45 minutes each for ion exchange to form a magnesium titanate pre-treated layer.

[0058] After washing and drying, the workpiece is immersed in a pulsed electrodeposition electrolyte (a solution of 0.05 mol / L EDTA-2Na and 0.02 mol / L AgNO3) and a pulsed current is applied with a peak current density of 1 A / dm³. 2 The pulse electrodeposition process was performed at a frequency of 125 Hz and a duty cycle of 35%. The pulse electrodeposition process employed a dual-pulse power supply: alternating positive pulses (peak current density 1.5 A / dm², ton = 5 ms, toff = 15 ms) and negative pulses (peak current density -0.5 A / dm², ton = 2 ms, toff = 10 ms) for a total duration of 8 minutes. This mode effectively avoids concentration polarization, resulting in a uniformly distributed silver deposition layer.

[0059] Then, heat treatment was performed in air, heating to 380 °C at a rate of 3 °C / min, holding for 3 hours, and then cooling with the furnace. This transformed silver into Ag₂O and AgO nanoparticles, which then remained stably present in the intermediate layer.

[0060] Construction of the COS-HNTs composite layer: 10 wt.% HNTs were ultrasonically dispersed in a 2 wt.% aqueous solution of acetic acid for 1 hour. 2.5 wt.% chitosan oligosaccharide was added and stirred until completely dissolved. Finally, 5 wt.% AlCl3 crosslinking agent was added, and the mixture was stirred at 55°C for 3 hours. After cooling, a precursor solution was obtained. The workpiece was immersed in the precursor solution and then dried and cured at room temperature to form a crosslinked composite layer. The workpiece was further immersed in a 1% (w / v) povidone-iodine solution for a brief 1 minute. After removal, excess droplets were blotted with filter paper, and the workpiece was dried again at room temperature to load iodine into the HNTs tubes. The coating surface was then gently rinsed with deionized water to remove loose adhering substances, vacuum dried at 70°C, and packaged for sterilization for later use. Example 2

[0061] This embodiment provides a method for preparing an antibacterial titanium alloy composite coating: Pretreatment of the titanium alloy substrate: Immerse the titanium alloy substrate in acetone solution at 25°C for 10 minutes to remove oil stains from the surface. Ultrasonically clean twice with deionized water for 3 minutes each time, ensuring no acetone solution residue remains. Immerse in a mixed solution of 9 wt.% nitric acid and 3 wt.% hydrofluoric acid at 25°C for 5 minutes to remove oxide scale and activate the surface. Rinse with deionized water with a resistivity ≥15 MΩ·cm to ensure no acid residue remains on the surface and allow for rapid entry into the next process, preventing secondary oxidation.

[0062] Constructing an inner porous titanium dioxide layer: The pretreated titanium alloy was used as the anode and placed in a micro-arc oxidation electrolyte. A porous titanium dioxide layer containing calcium and phosphorus was formed on the titanium alloy surface using a micro-arc oxidation process. After oxidation, the workpiece was ultrasonically cleaned with deionized water and dried. The micro-arc oxidation electrolyte formulation was: 0.15 mol / L Ca(CH3COO)2·H2O and 0.015 mol / L C3H7Na2O6P·5H2O, with the pH adjusted to 9.0 using NaOH. The micro-arc oxidation process parameters were: initial voltage of 100 V, increased to 340 V at a rate of 10 V / s, frequency of 500 Hz, duty cycle of 25%, and treatment time of 8 minutes. A circulating cooling system was used throughout the process to maintain the electrolyte temperature at 20℃.

[0063] Construction of the intermediate silver-loaded functional layer: The workpiece was further immersed in a 3 mol / L NaOH solution and treated at 60°C for 18 hours to form a sodium titanate layer on the surface. After rinsing with water, the workpiece was successively immersed in a 0.05 mol / L hydrochloric acid solution and a 0.05 mol / L strontium nitrate solution for 30 minutes each for ion exchange to form a strontium titanate pre-treated layer.

[0064] After washing and drying, the workpiece is immersed in a pulsed electrodeposition electrolyte (a solution of 0.05 mol / L EDTA-2Na and 0.02 mol / L AgNO3) and a pulsed current is applied with a peak current density of 0.5 A / dm³. 2 The pulse electrodeposition process was performed at a frequency of 50 Hz and a duty cycle of 20%. The pulse electrodeposition process employed a dual-pulse power supply: alternating positive pulses (peak current density 1.5 A / dm², ton = 5 ms, toff = 15 ms) and negative pulses (peak current density -0.5 A / dm², ton = 2 ms, toff = 10 ms) for a total duration of 8 minutes. This mode effectively avoids concentration polarization, resulting in a uniformly distributed silver deposition layer.

[0065] Then, heat treatment was performed in air, heating to 380°C at a rate of 3°C / min, holding for 3 hours, and then cooling with the furnace. This transformed silver into Ag₂O and AgO nanoparticles, which then remained stably present in the intermediate layer.

[0066] Construction of the COS-HNTs composite layer: 5 wt.% HNTs were ultrasonically dispersed in a 1 wt.% aqueous solution of acetic acid for 1 hour. 1.25 wt.% chitosan oligosaccharide was added and stirred until completely dissolved. Finally, 2.5 wt.% Al2(SO4)3 crosslinking agent was added, and the mixture was stirred at 50°C for 2 hours. After cooling, a precursor solution was obtained. The workpiece was immersed in the precursor solution and then dried and cured at room temperature to form a crosslinked composite layer. The workpiece was further immersed briefly in a 1% (w / v) povidone-iodine solution for 1 minute. After removal, excess droplets were blotted with filter paper, and the workpiece was dried again at room temperature to load iodine into the HNTs tubes. The coating surface was then gently rinsed with deionized water to remove loose adhering substances, vacuum dried at 70°C, and packaged for sterilization for later use. Example 3

[0067] This embodiment provides a method for preparing an antibacterial titanium alloy composite coating: Pretreatment of the titanium alloy substrate: Immerse the titanium alloy substrate in acetone solution at 25°C for 15 minutes to remove oil stains from the surface. Ultrasonically clean twice with deionized water for 3 minutes each time, ensuring no acetone solution residue remains. Immerse in a mixed solution of 15 wt.% nitric acid and 5 wt.% hydrofluoric acid at 25°C for 10 minutes to remove oxide scale and activate the surface. Rinse with deionized water with a resistivity ≥15 MΩ·cm to ensure no acid residue remains on the surface and allow for rapid entry into the next process, preventing secondary oxidation.

[0068] Constructing an inner porous titanium dioxide layer: The pretreated titanium alloy was used as the anode and placed in a micro-arc oxidation electrolyte. A porous titanium dioxide layer containing calcium and phosphorus was formed on the surface of the titanium alloy using a micro-arc oxidation process. After oxidation, the workpiece was ultrasonically cleaned with deionized water and dried. The micro-arc oxidation electrolyte formulation was: 0.25 mol / L Ca(CH3COO)2·H2O and 0.025 mol / L C3H7Na2O6P·5H2O, with the pH adjusted to 9.0 using NaOH. The micro-arc oxidation process parameters were: initial voltage of 100 V, increased to 380 V at a rate of 10 V / s, frequency of 500 Hz, duty cycle of 25%, and treatment time of 12 minutes. A circulating cooling system was used throughout the process to maintain the electrolyte temperature at 25℃.

[0069] Construction of the intermediate silver-loaded functional layer: The workpiece was further immersed in a 6 mol / L NaOH solution and treated at 75°C for 24 hours to form a sodium titanate layer on the surface. After rinsing with water, the workpiece was successively immersed in a 0.1 mol / L hydrochloric acid solution and a 0.1 mol / L magnesium nitrate solution for 60 minutes each for ion exchange to form a magnesium titanate pre-treated layer.

[0070] After washing and drying, the workpiece is immersed in a pulsed electrodeposition electrolyte (a solution of 0.05 mol / L EDTA-2Na and 0.02 mol / L AgNO3) and a pulsed current is applied with a peak current density of 1 A / dm³. 2 The pulse electrodeposition process was performed at a frequency of 125 Hz and a duty cycle of 35%. The pulse electrodeposition process employed a dual-pulse power supply: alternating positive pulses (peak current density 1.5 A / dm², ton = 5 ms, toff = 15 ms) and negative pulses (peak current density -0.5 A / dm², ton = 2 ms, toff = 10 ms) for a total duration of 8 minutes. This mode effectively avoids concentration polarization, resulting in a uniformly distributed silver deposition layer.

[0071] Then, heat treatment was performed in air, heating to 380°C at a rate of 3°C / min, holding for 3 hours, and then cooling with the furnace. This transformed silver into Ag₂O and AgO nanoparticles, which then remained stably present in the intermediate layer.

[0072] Construction of the COS-HNTs composite layer: 15 wt.% HNTs were ultrasonically dispersed in a 3 wt.% aqueous solution of acetic acid for 1 hour. 3.75 wt.% chitosan oligosaccharide was added and stirred until completely dissolved. Finally, 7.5 wt.% AlCl3 crosslinking agent was added, and the mixture was stirred at 60°C for 4 hours. After cooling, a precursor solution was obtained. The workpiece was immersed in the precursor solution and then dried and cured at room temperature to form a crosslinked composite layer. The workpiece was further immersed briefly in a 1% (w / v) povidone-iodine solution for 1 minute. After removal, excess droplets were blotted with filter paper, and the workpiece was dried again at room temperature to load iodine into the HNTs tubes. The coating surface was then gently rinsed with deionized water to remove loose adhering substances, vacuum dried at 70°C, and packaged and sterilized for later use.

[0073] In the above embodiments, the thickness of the inner porous titanium dioxide layer of the antibacterial titanium alloy composite coating is controlled to be 5-20 μm, the porosity of the inner porous titanium dioxide layer is 20-40%, and the average pore size of the inner porous titanium dioxide layer is 50-300 nm. The thickness of the intermediate silver-loaded functional layer is 1-5 μm, and the content of silver oxide nanoparticles is 0.5-5 wt.%. The thickness of the outer COS-HNTs composite layer is 0.5-3 μm, and the particle size of the silver oxide nanoparticles is 10-100 nm.

[0074] The antibacterial titanium alloy composite coatings prepared in the above embodiments were tested according to GB / T 13452.2-2008 "Determination of film thickness of paints and varnishes", and the coating thickness was 20-30 μm; according to GB / T6739-1996 "Peking Pencil Test for Coating Hardness", the coating hardness grade reached 3H or above; according to GB / T 9286-1998 "Cross-cut Test of Paint and Varnish Films", the film adhesion was grade 0; according to GB / T 1733-1993 "Test Method for Water Resistance of Paint Films" (boiling water method), the coating showed no blistering after 1000 hours; according to GB / T 21510-2008 "Test Method for Antibacterial Properties of Nano-inorganic Materials", the antibacterial rate against Escherichia coli and Staphylococcus aureus reached over 99.9%, and after an accelerated test simulating one month of daily use wear, the antibacterial rate against Escherichia coli and Staphylococcus aureus reached over 99%; according to ASTM... According to B117 "Standard Practice for Operating Salt Spray (Fog) Apparatus", the coating showed no corrosion after 1000 hours of neutral salt spray testing.

[0075] According to actual needs, titanium-based materials formed by titanium alloy matrix and antibacterial titanium alloy composite coating can be prepared into medical titanium alloy implants, such as bone plates and maxillofacial prostheses, which are suitable for orthopedics and dentistry.

[0076] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. An antibacterial titanium alloy composite coating, characterized by, The composite coating is located on a titanium alloy substrate and comprises, from inside to outside, an inner porous titanium dioxide layer, an intermediate silver-loaded functional layer, and an outer COS-HNTs composite layer. The intermediate silver-loaded functional layer is a silver-loaded magnesium titanate layer or a silver-loaded strontium titanate layer.

2. The antibacterial titanium alloy composite coating according to claim 1, characterized in that, the thickness of the inner porous titanium dioxide layer is 5-20 μm; the thickness of the intermediate silver-loaded functional layer is 1-5 μm; and the thickness of the outer COS-HNTs composite layer is 0.5-3 μm.

3. The antibacterial titanium alloy composite coating according to claim 2, characterized in that, the inner porous titanium dioxide layer is a porous titanium dioxide layer containing calcium and phosphorus elements; the silver in the intermediate silver-loaded functional layer is selected from silver oxide nanoparticles; the HNTs in the outer COS-HNTs composite layer are loaded with iodine ions or silver ions.

4. The method of producing an antibacterial titanium alloy composite coating according to any one of claims 1 to 3, characterized in that, comprising the following steps: S1. Pre-treating a titanium alloy substrate; S2. Using the pre-treated titanium alloy as an anode and placing it in an electrolyte, a porous titanium dioxide layer containing calcium and phosphorus elements is formed on the surface of the titanium alloy by a micro-arc oxidation process; the oxidized workpiece is ultrasonically cleaned with deionized water and dried; S3. Immersing the workpiece obtained in step S2 in an alkaline sodium compound solution to form a sodium titanate layer on the surface; after water washing, the workpiece is sequentially immersed in a hydrochloric acid solution and a magnesium nitrate or strontium nitrate solution for ion exchange, forming a magnesium titanate or strontium titanate pre-formation layer; S4. After water washing and drying, the workpiece is immersed in an electrolyte containing an EDTA-Ag complex for pulse electrodeposition; heat treatment is performed in an air atmosphere to obtain an intermediate silver-loaded functional layer; S5. Immersing the workpiece in a COS-HNTs precursor solution, then drying and curing at room temperature to form a cross-linked composite layer; immersing the workpiece in a povidone iodine solution for soaking, drying at room temperature, and loading iodine elements in the HNTs tubes; after rinsing the coating surface with deionized water, vacuum drying is performed.

5. The method of claim 4, wherein the method further comprises: In step S2, the electrolyte comprises 0.15-0.25 mol / L Ca(CH3COO)2·H2O and 0.01-0.03 mol / L C3H7Na2O6P·5H2O; the parameters of the micro-arc oxidation process are: voltage 340-380 V, frequency 400-600 Hz, duty cycle 25%, and time 8-12 minutes; the temperature of the electrolyte is 20-30℃.

6. The method of claim 4, wherein the method further comprises: In step S3, the alkaline sodium compound solution is a NaOH solution; the concentration of the NaOH solution is 3-8 mol / L; the treatment temperature is 60-90℃; and the treatment time is 18-36 hours; the concentration of the hydrochloric acid solution is 0.05-0.1 mol / L; the concentration of the magnesium nitrate solution is 0.05-0.1 mol / L; the concentration of the strontium nitrate solution is 0.05-0.1 mol / L; and the ion exchange time is 30-60 minutes.

7. The method of making an antibacterial titanium alloy composite coating of claim 4, wherein, In step S4, The electrolyte containing the EDTA-Ag complex is a solution of 0.05 mol / L EDTA-2Na and 0.02 mol / L AgNO3; The current density of the pulse electrodeposition is 0.5-2 A / dm 2 The frequency of the pulse electrodeposition is 50-200 Hz, and the duty cycle is 20-50%; the time of the pulse electrodeposition is 5-10 minutes; The temperature of the heat treatment is 350-400 ℃; and the time of the heat treatment is 2-4 hours.

8. The method of claim 4, wherein the method further comprises: In step S5, The preparation method of the COS-HNTs precursor solution is: 1-20 wt.% HNTs is ultrasonically dispersed in 1-3 wt.% acetic acid aqueous solution for 1 hour, 0.5-5 wt.% COS is added, stirred until completely dissolved, and finally AlCl3 or Al2(SO4)3 is added as a crosslinking agent, and stirred at 50-60 ℃ for 2-4 hours; The concentration of the povidone iodine solution is 1 %(w / v); and the soaking time is 1 minute.

9. A titanium-based material, characterized in that, The titanium-based material includes a titanium alloy substrate and the antibacterial titanium alloy composite coating as claimed in any one of claims 1-8.

10. Use of the titanium-based material in claim 9 in the preparation of a medical titanium alloy implant.