Coating deposition process for implant

Abstract

The invention discloses a coating deposition process for an implant, and relates to the technical field of implant coating preparation, and the deposition process comprises the following steps: S1, base material pretreatment: placing a base material in a deionized water mixed solution for ultrasonic cleaning, adopting low-temperature plasma purification treatment, utilizing high-energy particles of plasma to bombard the base material, and using the high-energy particles of the plasma to bombard the base material; the preparation method comprises the following steps: removing surface and internal impurities, introducing active groups, forming a nanoscale rough interface with the surface roughness Ra of 50-200nm on the surface of a base material through a chemical etching process and femtosecond laser etching synergistic process, and carrying out vacuum drying on the base material; s2, metal gasification: placing a metal tantalum raw material in an upstream heating zone of the reaction chamber; the chemical vapor deposition (CVD) technology is adopted, osseointegration can be promoted, the infection risk can be reduced, the method is suitable for porous implantation instruments of the orthopedics department, the dental department and the like, the obtained coating technology is compatible with a complex base material structure, the clinical curative effect and the life quality of a patient are improved, large-scale production is supported, and development of a new material industry chain is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of implant coating preparation, and specifically relates to a coating deposition process for implants. Background Art

[0002] With the progress of materials science, biomechanics and manufacturing technology, the research on medical implants has gradually developed towards high biocompatibility, long lifespan and intelligence. Implants are widely used in the fields of orthopedics, cardiovascular, dentistry and soft tissue repair. Its development is driven by material innovation, function upgrade and personalized design. The demand stems from multiple factors such as the urgent need for clinical treatment, the progress of materials science and technology, the challenges of coping with implant limitations, and the market expansion under policy support.

[0003] As the core technology in the field of biomaterials, the surface coating of implants endows the implant with multiple functions through physical, chemical or biological modification, and significantly optimizes its interaction with the human body environment. The primary function of the coating is to enhance biocompatibility. For example, titanium oxide or polyethylene glycol coatings are used to reduce immune rejection and inflammatory reactions, ensuring the "peaceful coexistence" of the implant and tissues. In the fields of orthopedics or dentistry, biomimetic coatings such as hydroxyapatite simulate the components of natural bone, promote the adhesion and proliferation of osteoblasts, and accelerate the bone integration process; while the collagen coating on the surface of vascular stents guides the growth of endothelial cells to achieve efficient repair of soft tissues. In response to the risk of postoperative infection, coating technology actively sterilizes through strategies such as silver loading, antibiotic slow release or nano-zinc oxide, and at the same time uses micro-nano structures to inhibit the formation of bacterial biofilms, building an anti-infection defense line for implants. For metal implants, hard coatings such as diamond-like carbon can reduce the release of metal ions, avoid toxicity problems caused by long-term corrosion, and extend the service life.

[0004] There are different limitations in various implant coating processes: Plasma spraying requires high-temperature operation, which may damage the substrate, and the coating has a high porosity and limited bonding strength. Ceramic materials are prone to decomposition at high temperatures, reducing their activity; Electrochemical deposition depends on a conductive substrate, has a slow deposition rate, and the electrolyte may remain and cause pollution; Physical vapor deposition (PVD) has high equipment costs and low efficiency, and it is easy to have uneven coating thickness on complex-shaped workpieces; The coatings prepared by the sol-gel method are brittle, and drying shrinkage is easy to cause cracking, and the process cycle is relatively long. The cost of 3D printing equipment is extremely high, the post-treatment is complex, the material selection is limited, and it is difficult to print pure ceramics; The process parameters of laser surface treatment are sensitive, the equipment maintenance cost is high, and the thermal expansion coefficients of the materials need to be strictly matched; The coating thickness of dip coating is uneven, the bonding strength is low, and the solvent residue may cause toxicity; Atomic layer deposition (ALD) has an extremely slow rate, the equipment is complex and expensive, and its industrial application is limited. These disadvantages restrict the improvement of coating performance and large-scale application. In view of this, we have proposed a coating deposition process for implants. Summary of the Invention

[0005] To solve the above technical problems, a coating deposition process for implants is provided, and the present technical solution solves the above problems.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a coating deposition process for implants, and the deposition process includes the following steps:

[0007] S1. Substrate pretreatment: Place the substrate in a mixed solution of deionized water for ultrasonic cleaning, and perform low-temperature plasma purification treatment. Use the high-energy particles of the plasma to bombard the substrate to remove surface and internal impurities and introduce active groups. Through the synergistic process of chemical etching process and femtosecond laser etching, a nanoscale rough interface with a surface roughness Ra of 50 - 200 nm is formed on the substrate surface, and the substrate is dried in vacuum.

[0008] S2. Metal vaporization: Place the tantalum metal raw material in the heating area upstream of the reaction chamber. Based on the molecular pump group, evacuate to the system pressure to remove impurity gases. Introduce Cl2 gas at high temperature, regulate the flow rate through the mass flow controller, react tantalum with chlorine gas to generate TaCl5 vapor, and design the reaction chamber structure to uniformly heat the substrate and evenly distribute the gas.

[0009] S3. Tantalum coating deposition: Mix the generated TaCl5 vapor and hydrogen gas in a molar ratio as the precursor gas and input it onto the surface of the pretreated substrate. Heat up in stages, use gradient heating to reach the target temperature, and use infrared temperature measurement closed-loop control technology to maintain the temperature stability.

[0010] S4. Post-treatment process: Use ultrasonic solvent cleaning combined with dilute acid treatment to remove residues, perform high-temperature annealing in an inert atmosphere, perform polishing and passivation treatment, and introduce plasma-enhanced CVD to reduce the deposition temperature.

[0011] Preferably, the low-temperature plasma purification treatment step in step S1 is as follows:

[0012] Preparatory work: Check and debug the equipment and pretreat the substrate, and select and prepare appropriate gases.

[0013] Place the pretreated substrate on the sample rack in the reaction chamber, close the reaction chamber door, start the vacuum system, perform vacuum pumping, gradually reduce the pressure in the chamber, and pump the vacuum degree to the predetermined value.

[0014] When the reaction chamber reaches the predetermined vacuum degree, introduce the working gas into the chamber according to the set gas flow rate, adjust the gas flow meter, and control the gas flow rate within 10 - 100 sccm.

[0015] Start the plasma generator, and according to the tolerance and treatment requirements of the substrate, adjust the power to the range of 50 - 500 W. The high-energy particles start to bombard the substrate surface for purification and modification treatment.

[0016] Preferably, the chemical etching process and the femtosecond laser etching collaborative process step in step S1 are as follows:

[0017] Ultrasonically clean the metal with acetone, rinse the semiconductor with deionized water and ethanol and then dry it, and debug the femtosecond laser equipment;

[0018] Immerse the substrate in the chemical etching solution to initially form a micron-level rough structure, control the etching time and temperature, and terminate the reaction by washing with water after completion;

[0019] Use femtosecond laser to scan and etch with set parameters. Based on the target roughness, set the laser parameters. Use a femtosecond laser with a wavelength of 515 nm, a pulse width of 50 fs, and a repetition frequency of 1 kHz to scan and etch the surface of the substrate at a scanning speed of 10 - 20 mm / s. Through the high energy density of the laser, form nano-level pits and protrusion structures on the surface of the substrate;

[0020] Based on real-time observation by SEM and AFM, dynamically adjust the chemical etching time and laser energy parameters to achieve the target roughness. Finally, remove the residues by ultrasonic cleaning and detect again to ensure that the surface roughness meets the standard.

[0021] Preferably, the vacuum drying time in step S1 is 2 h and the vacuum drying temperature is 120 °C.

[0022] Preferably, the vacuum pumping pressure in step S2 is 10 - 3 - 10 - 2P a , introduce Cl2 gas with a purity ≥ 99.999% at a high temperature of 800 - 1200 °C, adjust the Cl2 flow rate to 10 - 200 sccm through a mass flow controller, and react tantalum with chlorine gas to generate TaCl5 vapor;

[0023] Among them, the flow rate of Cl2 gas is precisely regulated by a mass flow controller, and the error range ≤ ±2%.

[0024] Preferably, in step S3, the target temperature is 800 - 1200 °C, the pressure is 800 - 1500 Pa, the deposition time is 5 - 10 h, and the molar ratio of TaCl5 vapor to hydrogen is 10:1 - 5:1.

[0025] Preferably, the polishing and passivation treatment method in step S4 is one of mechanical polishing and anodic passivation treatment, the annealing temperature is 1000 - 1200 °C, and the annealing time is 1 - 3 h.

[0026] Preferably, the vacuum treatment is carried out by pumping the vacuum degree in the reaction chamber to 1-100 Pa and adjusting the plasma power to 50-500 W. When the power is low, the particle energy is weak, and gentle treatment is performed on materials with poor tolerance; when the power is higher, it is applicable to substrates with high hardness and stubborn impurities, increasing the particle bombardment force.

[0027] Preferably, the chemical etching time is 3-15 min, the etching temperature is 25-60 °C, and the stirring speed is 50-200 rpm.

[0028] Preferably, the final coating thickness prepared is 2–20 μm, the bonding strength is ≥30 MPa, and it is applicable to bone implant applications.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The present invention adopts chemical vapor deposition (CVD) technology to prepare a medical tantalum coating through four steps. By precisely controlling the substrate pretreatment, TaCl gas-phase synthesis, coating deposition parameters, and post-treatment process, the coating obtained by the process has a thickness of 2–20 μm and a bonding strength of ≥30 MPa. It has an elastic modulus similar to that of human cancellous bone, and has both biocompatibility and mechanical stability. It can promote bone integration and reduce the risk of infection, and is applicable to porous implant devices in orthopedics, dentistry, etc. The obtained coating process is compatible with complex substrate structures, improves clinical efficacy and the quality of life of patients, supports large-scale production, and promotes the development of the new material industry chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart for preparing the deposition process of the present invention;

[0032] Figure 2 It is a process flow chart for the low-temperature plasma purification treatment step. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.

[0034] Referring to Figure 1 As shown, a coating deposition process for implants, the deposition process includes the following steps:

[0035] S1. Substrate pretreatment: Place the substrate in a mixed solution of deionized water for ultrasonic cleaning, and use low-temperature plasma purification treatment. Use the high-energy particles of the plasma to bombard the substrate, remove surface and internal impurities, and introduce active groups. Through the synergistic process of chemical etching process and femtosecond laser etching, a nanoscale rough interface with a surface roughness Ra of 50-200 nm is formed on the substrate surface, and the substrate is dried in vacuum;

[0036] S2. Metal gasification: Place the tantalum metal raw material in the heating zone upstream of the reaction chamber. Evacuate the system to remove impurity gases based on the molecular pump set until the system pressure is reached. Introduce Cl2 gas at high temperature, regulate the flow rate through a mass flow controller, react tantalum with chlorine gas to generate TaCl5 vapor, and design the reaction chamber structure to uniformly heat the substrate and evenly distribute the gas.

[0037] S3. Tantalum coating deposition: Mix the generated TaCl5 vapor and hydrogen in a molar ratio as the precursor gas and input it onto the surface of the pretreated substrate. Heat up in stages, use gradient heating to reach the target temperature, and use infrared temperature measurement closed-loop control technology to maintain temperature stability.

[0038] S4. Post-treatment process: Use ultrasonic solvent cleaning combined with dilute acid treatment to remove residues, perform high-temperature annealing in an inert atmosphere, perform polishing and passivation treatment, and introduce plasma-enhanced CVD to reduce the deposition temperature.

[0039] The process of this application improves the coating adhesion through multi-stage treatment, precisely controls the temperature and gas flow to ensure the coating uniformity, optimizes the material properties through post-treatment, has the characteristics of strong corrosion resistance and good high-temperature stability, is applicable to the fields of aerospace and electronic devices, and the process is environmentally friendly and has wide applicability.

[0040] Refer to Figure 2 As shown, the steps of using low-temperature plasma purification treatment in step S1 are as follows:

[0041] Preparatory work: Check and debug the equipment and pretreat the substrate, and select and prepare suitable gases.

[0042] Place the pretreated substrate on the sample rack in the reaction chamber, close the reaction chamber door, start the vacuum system, perform vacuum pumping, gradually reduce the pressure in the chamber, and pump the vacuum degree to the predetermined value.

[0043] When the reaction chamber reaches the predetermined vacuum degree, introduce the working gas into the chamber according to the set gas flow rate, adjust the gas flow meter, and control the gas flow rate within 10 - 100 sccm.

[0044] Start the plasma generator, adjust the power to the range of 50 - 500 W according to the tolerance and treatment requirements of the substrate, and high-energy particles begin to bombard the surface of the substrate for purification and modification treatment.

[0045] The equipment debugging and gas selection in the early stage of this application can ensure the stable and efficient operation of the entire treatment process, laying a foundation for the subsequent treatment effect. Placing the substrate in the reaction chamber and evacuating it can effectively exclude the interference of impurity gases such as air, creating a pure reaction environment and avoiding side reactions between impurities and the substrate or working gas. Precisely controlling the flow rate of the working gas can make the gas evenly distributed in the chamber, ensuring sufficient and uniform contact between the plasma and the substrate. Flexibly adjusting the power of the plasma generator according to the characteristics of the substrate can not only use high-energy particles to bombard and remove impurities such as oil stains and oxides on the substrate surface, but also introduce a large number of active groups without overly damaging the substrate, significantly enhancing the surface energy and surface activity of the substrate, providing a more solid bonding foundation for subsequent coating deposition and enhancing the adhesion between the coating and the substrate.

[0046] The chemical etching process and the femtosecond laser etching collaborative process steps in step S1 are as follows:

[0047] Ultrasonically clean the metal with acetone, rinse the semiconductor with deionized water and ethanol and then dry it, and debug the femtosecond laser equipment;

[0048] Immerse the substrate in the chemical etching solution to initially form a micron-scale rough structure, control the etching time and temperature, and terminate the reaction by washing with water after completion;

[0049] Use a femtosecond laser to scan and etch with set parameters. Based on the target roughness, set the laser parameters. Use a femtosecond laser with a wavelength of 515 nm, a pulse width of 50 fs, and a repetition frequency of 1 kHz to scan and etch the surface of the substrate at a scanning speed of 10 - 20 mm / s. Through the high energy density of the laser, form nano-scale pits and protrusions on the substrate surface;

[0050] Based on real-time observation by SEM and AFM, dynamically adjust the chemical etching time and laser energy parameters to achieve the target roughness. Finally, remove the residues by ultrasonic cleaning and re-detect to ensure that the surface roughness meets the standard.

[0051] In the pre-treatment stage of this application, targeted cleaning of different materials and debugging of the femtosecond laser equipment lay a solid foundation for the process. Chemical etching first shapes a micron-scale rough structure, building a framework for subsequent treatment. And by controlling the etching time and temperature, the initial roughness can be flexibly adjusted. The femtosecond laser, with its ultra-short pulses and high energy density, quickly forms nano-scale pits and protrusions on the substrate surface, making up for the deficiencies of chemical etching at the nano-scale and improving the surface fineness. SEM and AFM are used for real-time observation and dynamic parameter adjustment to ensure that the target roughness can be accurately achieved, avoiding over-etching or insufficient effects. Finally, through ultrasonic cleaning and detection, the surface is ensured to be clean and the roughness meets the standard. This collaborative process can not only significantly increase the specific surface area of the substrate, but also form a multi-level rough structure, greatly enhancing the mechanical interlocking and physical adsorption capabilities between the coating and the substrate, and significantly improving the coating adhesion and bonding strength.

[0052] The vacuum drying time in step S1 is 2 h, and the vacuum drying temperature is 120°C.

[0053] The vacuum pressure in step S2 is 10 - 3-10 - 2P a , introducing Cl2 gas with a purity of ≥99.999% at a high temperature of 800-1200°C, adjusting the Cl2 flow rate to 10-200 sccm through a mass flow controller, so that tantalum reacts with chlorine to generate TaCl5 vapor;

[0054] The flow rate of Cl2 gas is precisely controlled by a mass flow controller with an error range of ≤±2%.

[0055] In step S3, the target temperature is 800-1200° C., the pressure is 800-1500 Pa, the deposition time is 5-10 h, and the molar ratio of TaCl5 vapor to hydrogen is 10:1-5:1.

[0056] The high vacuum environment of the present application can significantly reduce the impurity gas content in the chamber, avoid the reaction of oxygen, water vapor, etc. with tantalum or chlorine to generate oxide impurities, and ensure the high purity of the generated TaCl vapor; high temperature conditions can significantly increase the reactivity of tantalum and chlorine, promote the full reaction, and increase the yield of gas-phase products; high-purity chlorine gas combined with the precise regulation of the mass flow controller can stabilize the concentration and partial pressure of the reaction gas, avoid violent or insufficient local reactions caused by flow fluctuations, ensure the uniformity and controllability of the gas-phase synthesis process, and provide a pure and stable precursor gas source for subsequent coating deposition;

[0057] In S3, the setting of the target temperature and pressure range takes into account the chemical adsorption efficiency of TaCl5 vapor and the kinetic requirements of the hydrogen reduction reaction. The low-temperature stage promotes vapor physical adsorption, and the high-temperature stage triggers the reduction reaction. The gradient heating mode can reduce the stress accumulation in the coating. The specific molar ratio of TaCl5 to hydrogen can ensure that the reduction reaction is fully carried out to avoid residual or excessive consumption of reactants. With sufficient deposition time, a tantalum coating with appropriate thickness and dense structure can be formed. The overall process realizes efficient synthesis of precursor gas and uniform growth of coating through multi-parameter coordinated control, ensuring the purity of coating composition, structural density and performance stability.

[0058] The polishing and passivation treatment method in step S4 is one of mechanical polishing and anodic passivation treatment, the annealing temperature is 1000-1200° C., and the annealing time is 1-3 hours.

[0059] The vacuum pumping process involves pumping the vacuum degree in the reaction chamber to 1 - 100 Pa and adjusting the plasma power to 50 - 500 W. When the power is low, the particle energy is weak, and gentle treatment can be carried out on materials with poor tolerance. When the power is higher, it is applicable to substrates with high hardness and stubborn impurities to increase the particle bombardment intensity.

[0060] The chemical etching time is 3 - 15 min, the etching temperature is 25 - 60 °C, and the stirring speed is 50 - 200 rpm.

[0061] The final coating prepared has a thickness of 2–20 μm and a bonding strength of ≥30 MPa, and is suitable for bone implant applications.

[0062] Example 1

[0063] A coating deposition process for implants, and the deposition process includes the following steps:

[0064] First, perform substrate pretreatment. Place it in a mixed solution with deionized water for ultrasonic cleaning to effectively remove the oil stains on the surface of the porous carbon. Then, use low-temperature plasma purification treatment. Utilize the high-energy particles of the plasma to bombard the substrate, remove surface and internal impurities, and introduce active groups. Through the synergistic process of chemical etching and femtosecond laser etching, a nanoscale rough interface with a surface roughness Ra of 50 - 200 nm is formed on the substrate surface, and then the substrate is dried in vacuum.

[0065] In the second step, tantalum reacts with chlorine in a high-temperature reaction furnace to generate TaCl5. Heat it to 800 - 1200 °C to make the tantalum metal reach an active state capable of reacting with chlorine. Then, with the help of a gas flow control system, introduce Cl2 with a purity of ≥99.999%, and precisely control the flow rate of chlorine to 10 - 200 sccm through a mass flow controller. React tantalum metal (Ta) directly with chlorine (Cl2) to generate tantalum pentachloride (TaCl5). Through this design, the substrate can be uniformly heated, ensuring that the reaction gas can be evenly distributed in the reaction space.

[0066] The third step is to determine the deposition process parameters. Use the generated tantalum pentachloride (TaCl5) vapor mixed with hydrogen (H2) as the precursor gas. The reaction temperature needs to be strictly controlled at 800 - 1200 °C, the reaction pressure is set at 800 - 1500 Pa, and the deposition time is 5 - 10 hours. Ensure the temperature stability through infrared temperature measurement closed-loop control technology, and select appropriate deposition temperature, time, and pressure according to the substrate characteristics.

[0067] The fourth step is post-processing. First, it is necessary to thoroughly clean and remove residues. Ultrasonic solvent cleaning combined with dilute acid treatment is used to ensure the smoothness of the porous structure. Subsequently, high-temperature annealing is carried out to eliminate internal stress and enhance the coating adhesion. For rough surfaces or functional requirements, polishing or passivation treatment can be performed to improve corrosion resistance and biocompatibility. Finally, strict testing is required: scratch testing for bond strength, micro-CT to verify porosity, electrochemical testing to evaluate corrosion resistance, and medical applications also need to meet the ISO 10993 biocompatibility standard. The entire process needs to be completed in a clean environment to ensure that the product meets the specific requirements of mechanical properties, functionality, and application scenarios;

[0068] The porous tantalum implant made of tantalum-porous carbon substrate can reduce the elastic modulus through the porous structure, avoid the "stress shielding effect", and at the same time use the high strength of tantalum to bear the bone load and match the human mechanical environment. In addition, the standardized preparation process supports large-scale production, with significant cost advantages, and is suitable for the manufacture of composite structures, with both good mechanical strength and customization potential.

[0069] Comparative Example 1

[0070] Select a suitable volatile precursor gas. When choosing a medical tantalum coating, select a volatile compound gas containing tantalum; prepare the reaction chamber and pump it to a relatively low vacuum to ensure that the mean free path of the reactants and residual gases is long enough, and properly place the implant substrate to be coated in the reaction chamber;

[0071] Introduce one or more volatile precursor gases into the reaction chamber, raise the temperature of the reaction chamber to promote the chemical reaction of the precursor, and grow a silicon film with trichlorosilane (SiHCl3). The reaction process is: SiHCl3 (gas) → Si (solid) + 3HCl (gas). By precisely controlling the reaction conditions, including temperature, pressure, and gas flow ratio parameters, the growth rate, particle size, orientation, composition, and stoichiometry of the film layer can be adjusted;

[0072] The substances generated by the reaction are gradually deposited on the surface of the implant substrate to form the required coating. After the reaction is completed, wait for the reaction chamber to cool, take out the implant with the coating, and perform subsequent cleaning and testing processes.

[0073] Comparative Example 2

[0074] Select a conductive porous implant, and use acetone, absolute ethanol, or deionized water to perform ultrasonic treatment on it for 15 - 20 minutes respectively to remove surface impurities and improve surface cleanliness and activity;

[0075] Prepare the electrophoresis solution: Dissolve acetic acid and chitosan in a water solvent and mix well to make the electrophoresis solution;

[0076] Using the pre-treated conductive porous implant as the cathode and the stainless-steel ring as the anode, place them in the electrophoresis solution. Under the constant current mode, a circular electric field is formed on the surface of the porous implant. Use a peristaltic pump as the power source to overcome gravity for the electrophoresis solution, and perform anti-gravity perfusion of the electrophoresis solution, so that both the inside and outside of the conductive porous implant can be filled with the electrophoresis solution and the electrophoresis solution in the electric field area can be continuously updated. During this process, control the distance between the stainless-steel ring and the surface of the conductive porous implant to be 0.8 - 1.5 cm, the applied current to be 12 - 24 mA, the electrophoresis deposition time to be 2.5 - 10 min, and the perfusion speed of the electrophoresis solution to be 0 - 14 ml / min. Finally, a coating is prepared on the surface of the porous implant.

[0077] Perform performance tests on Example 1, Comparative Example 1, and Comparative Example 2 comprehensively;

[0078] Bond strength test

[0079] Sample preparation: Select 3 - 5 representative samples from Example 1, Comparative Example 1, and Comparative Example 2;

[0080] Experimental operation: Adopt the scratch test method. Use a scratch tester to scratch the coating surface with a diamond indenter at a certain speed and loading force, continuously increase the load until the coating peels off, and record the critical load when the coating peels off. The larger this load value is, the higher the bond strength between the coating and the substrate;

[0081] Data processing: Conduct statistical analysis on the critical load data of multiple samples, and calculate the average value and standard deviation parameters;

[0082] Coating thickness test

[0083] Instrument selection: Use a scanning electron microscope (SEM) or a metallurgical microscope;

[0084] Sample preparation: Cut, mount, grind, and polish the sample so that its cross-section can be clearly observed;

[0085] Measurement operation: Under the microscope, select multiple different positions to measure the thickness of the coating, and measure at least 5 points for each sample;

[0086] Result analysis: Calculate the average value and standard deviation of the thickness of each measurement point, and evaluate the uniformity of the coating thickness; Chemical composition analysis

[0087] Instrument selection: Use an energy-dispersive X-ray spectrometer (EDX) or an X-ray photoelectron spectrometer (XPS);

[0088] Detection process: Place the sample on the instrument detection table, scan and analyze the coating surface, and obtain the elemental composition of the coating and the content ratio of each element;

[0089] Data interpretation: Compare with the design requirements of the chemical composition of the target coating to determine whether the chemical composition of the coating meets the expectations.

[0090] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A coating deposition process for an implant, characterized in that, The deposition process includes the following steps: S1. Substrate pretreatment: The substrate is ultrasonically cleaned in a deionized water mixed solution, and then purified by low-temperature plasma treatment. The high-energy particles of the plasma bombard the substrate to remove surface and internal impurities and introduce active groups. Through the synergistic process of chemical etching and femtosecond laser etching, a nanoscale rough interface with a surface roughness Ra of 50 - 200 nm is formed on the substrate surface, and then the substrate is dried in vacuum. S2. Metal vaporization: The tantalum metal raw material is placed in the heating area upstream of the reaction chamber. The system is evacuated to remove impurity gases based on the molecular pump group until the system pressure is reached. Cl2 gas is introduced at high temperature, and the flow rate is regulated by a mass flow controller. Tantalum reacts with chlorine gas to generate TaCl5 vapor. The substrate is uniformly heated and the gas is uniformly distributed by designing the reaction chamber structure. S3. Tantalum coating deposition: The generated TaCl5 vapor and hydrogen are mixed as precursor gases in a molar ratio and input onto the surface of the pretreated substrate. The temperature is increased in stages, and the temperature is raised to the target temperature by gradient heating. The infrared temperature measurement closed-loop control technology is used to maintain the temperature stability. S4. Post-treatment process: Ultrasonic solvent cleaning combined with dilute acid treatment is used to remove residues. High-temperature annealing is carried out in an inert atmosphere, polishing and passivation treatment are performed, and plasma-enhanced CVD is introduced to reduce the deposition temperature.

2. The coating deposition process for an implant according to claim 1, wherein, The steps of low-temperature plasma purification treatment in step S1 are as follows: Preparatory inspection, debugging of equipment and pretreatment of the substrate, and selection of appropriate gases are prepared. The pretreated substrate is placed on the sample rack in the reaction chamber. The reaction chamber door is closed, the vacuum system is started, and vacuum pumping is carried out. The pressure in the chamber is gradually reduced until the vacuum degree is pumped to the predetermined value. When the reaction chamber reaches the predetermined vacuum degree, the working gas is introduced into the chamber according to the set gas flow rate. The gas flow meter is adjusted to control the gas flow rate within the range of 10 - 100 sccm. The plasma generator is started. According to the tolerance and treatment requirements of the substrate, the power is adjusted to the range of 50 - 500 W. The high-energy particles start to bombard the surface of the substrate for purification and modification treatment.

3. A coating deposition process for an implant according to claim 1, characterized in that, The steps of the synergistic process of chemical etching and femtosecond laser etching in step S1 are as follows: The metal is ultrasonically cleaned with acetone, and the semiconductor is rinsed with deionized water and ethanol and then dried. The femtosecond laser equipment is debugged. The substrate is immersed in the chemical etching solution to initially form a micron-scale rough structure. The etching time and temperature are controlled, and after completion, the reaction is terminated by washing with water. The femtosecond laser is used to scan and etch with set parameters. Based on the target roughness, the laser parameters are set. The femtosecond laser with a wavelength of 515 nm, a pulse width of 50 fs, and a repetition frequency of 1 kHz is used to scan and etch the surface of the substrate at a scanning speed of 10 - 20 mm / s. Through the high energy density of the laser, nano-scale pits and protrusions are formed on the substrate surface. Based on real-time observation by SEM and AFM, the chemical etching time and laser energy parameters are dynamically adjusted to achieve the target roughness. Finally, the residues are removed by ultrasonic cleaning, and the surface roughness is rechecked to ensure compliance with the standard.

4. A coating deposition process for an implant according to claim 1, characterized in that, The vacuum drying time in step S1 is 2 h, and the vacuum drying temperature is 120 °C.

5. A coating deposition process for an implant according to claim 1, characterized in that, The vacuum pressure in step S2 is 10 - 3 - 10 - 2P a , and Cl2 gas with a purity of ≥99.999% is introduced at a high temperature of 800 - 1200°C. The flow rate of Cl2 is adjusted to 10 - 200 sccm through a mass flow controller to react tantalum with chlorine to generate TaCl5 vapor; The flow rate of Cl2 gas is precisely regulated by the mass flow controller, and the error range is ≤ ±2%.

6. A coating deposition process for an implant according to claim 1, characterized in that, In step S3, the target temperature is 800 - 1200 °C, the pressure is 800 - 1500 Pa, the deposition time is 5 - 10 h, and the molar ratio of TaCl5 vapor to hydrogen is 10:1 - 5:

1.

7. A coating deposition process for an implant according to claim 1, characterized in that, In step S4, the polishing and passivation treatment method is one of mechanical polishing and anodic passivation treatment. The annealing temperature is 1000 - 1200 °C, and the annealing time is 1 - 3 h.

8. A coating deposition process for an implant according to claim 2, characterized in that, The vacuum pumping treatment is carried out by pumping the vacuum degree in the reaction chamber to 1 - 100 Pa and adjusting the plasma power to 50 - 500 W. When the power is low, the particle energy is weak, and gentle treatment is performed on materials with poor tolerance; when the power is higher, it is applicable to substrates with high hardness and stubborn impurities to increase the particle bombardment intensity.

9. A coating deposition process for an implant according to claim 3, characterized in that, The chemical etching time is 3 - 15 min, the etching temperature is 25 - 60 °C, and the stirring speed is 50 - 200 rpm.

10. A coating deposition process for an implant according to claim 1, characterized in that, The finally prepared coating has a thickness of 2 - 20 μm and a bonding strength of ≥ 30 MPa, and is applicable to bone implant applications.

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