Surface treatment method and application of medical zirconium niobium alloy

Abstract

This application proposes a surface treatment method and application for medical zirconium-niobium alloys. The surface treatment method includes: pre-oxidation treatment, pickling, complexation dissolution, and surface activation treatment of the medical zirconium-niobium alloy. The surface treatment method for medical zirconium-niobium alloys in this application employs a composite treatment mechanism of "pre-oxidation buffer - mild pickling - complexation chemical dissolution of SPP - surface activation," which chemically dissolves SPP at its source, completely avoiding the residual problems that may be caused by the physical shedding of SPP in related technologies. Furthermore, it avoids biocompatibility risks such as oxalates throughout the process, achieving perfect compatibility with subsequent high-temperature oxidation processes.

Description

Technical Field

[0001] This application relates to the field of alloy surface treatment technology, and in particular to a surface treatment method and application for medical zirconium-niobium alloy. Background Technology

[0002] Zr-2.5Nb-0.1O zirconium-niobium alloys (also known as Zr-Nb alloys) are excellent medical metal materials, possessing good biocompatibility, corrosion resistance, and mechanical strength. After high-temperature oxidation, a dense oxide film can be formed on its surface, which can further enhance the material's biocompatibility and resistance to body fluid corrosion. It is widely used in the manufacturing of implantable medical devices such as orthopedic implants and dental prostheses.

[0003] Before high-temperature oxidation at 500-700℃, zirconium-niobium alloy rods such as Zr-2.5Nb-0.1O will have residual oxide scale, oil stains, metal debris, micro-scratches, oxidation defects, and other processing defects on their surface. In addition, the β-Zr phase inside the alloy is prone to decomposition during processing to form niobium-rich secondary phase particles. These impurities and defects will seriously affect the density, uniformity, and adhesion of the oxide film after high-temperature oxidation, leading to easy detachment of the oxide film and reduced corrosion resistance. This will affect the clinical safety and service life of medical devices. Therefore, the alloy surface must be surface treated before high-temperature oxidation to obtain a clean and uniform surface state to ensure the quality of the subsequent oxide film.

[0004] Currently, surface treatment of Zr-Nb alloys mostly follows the hydrofluoric acid-nitric acid mixed pickling process used in the nuclear industry, which has the following problems: (1) Insufficient understanding of the formation mechanism and removal methods of SPP: SPP is a second-phase particle of the alloy itself. During a pickling process, because the Zr matrix dissolves faster than the Nb-rich SPP, the SPP is exposed from the interior of the alloy and adheres to the surface after the matrix dissolves. Although related technologies recognize this problem, they propose using an acidified oxalic acid or ammonium oxalate washing solution to dissolve the hydrated zirconium oxide layer, which acts as an "adhesive," thereby causing the SPP to detach. This method does not directly dissolve the SPP, and the detached SPP particles may still remain on the surface as solid waste, and there is a risk of oxalic acid residue. This is not the best solution for medical implants with stringent requirements.

[0005] (2) Severe pickling parameters: Typical processes use high concentrations of HF and HNO3 and long-term treatment, which leads to severe dissolution of the Zr matrix, large-scale exposure and shedding of SPP, uneven surface roughness, easy pitting and over-corrosion, and difficulty in obtaining a uniform substrate required for subsequent precision oxidation processes.

[0006] (3) Limitations of the secondary treatment system: The relevant technology uses an oxalic acid + nitric acid system to remove SPP, and its mechanism of action is physical "release" rather than chemical "dissolution". This leads to two problems: first, the detached SPP particles may be re-adsorbed; second, oxalic acid itself is an organic acid with questionable biocompatibility and should be avoided as much as possible in the surface treatment process of medical implants.

[0007] (4) Reliance on mechanical wiping: In order to remove "black powder", the relevant processes often need to be combined with water spraying or mechanical wiping, which can easily cause surface scratches and damage the surface integrity.

[0008] (5) Failure to consider the biocompatibility requirements of medical materials: Traditional acid pickling processes used in the nuclear industry do not take into account the special requirements of medical materials. Residual fluoride ions, oxalate ions, etc., may affect the formation of oxide film during high-temperature oxidation, or remain as impurities on the surface of the final product, posing a potential threat to biosafety.

[0009] Therefore, there is an urgent need to design a surface treatment method that is compatible with the characteristics of medical zirconium-niobium alloys, especially Zr-2.5Nb-0.1O alloy rods, and can achieve a clean, undamaged surface while meeting the requirements of medical biocompatibility, so as to solve the above-mentioned technical problems. Summary of the Invention

[0010] In view of this, one objective of this application is to address the shortcomings of pickling processes in related technologies for zirconium-niobium alloys, such as medical-grade Zr-2.5Nb-0.1O alloy rods, by developing a multi-step synergistic high-temperature oxidation pre-oxidation surface treatment method—a surface treatment method for medical zirconium-niobium alloys. This method solves the problems of incomplete cleaning, easy surface damage, residual acid affecting oxide film quality, and incompatibility with biocompatibility requirements of medical materials caused by pickling methods in related technologies. This surface treatment method for medical zirconium-niobium alloys employs a composite treatment mechanism of "pre-oxidation buffer - mild pickling - complexation chemical dissolution of SPP - surface activation," chemically dissolving SPP at its source, completely avoiding the residual problems that may be caused by the physical shedding of SPP in related technologies. Furthermore, it avoids biocompatibility risks such as oxalates throughout the process, achieving perfect compatibility with subsequent high-temperature oxidation processes.

[0011] Another objective of this application is to provide an application of a surface treatment method for medical zirconium-niobium alloys.

[0012] To achieve the above objectives, the first aspect of this application proposes a surface treatment method for medical zirconium-niobium alloys, comprising: The medical zirconium-niobium alloy is subjected to pre-oxidation treatment, pickling, complexation dissolution and surface activation treatment.

[0013] In some embodiments, the pre-oxidation treatment includes: heat-treating the medical zirconium-niobium alloy in an oxidizing gas atmosphere.

[0014] In some embodiments, the oxidizing gas includes at least one of air, oxygen, and a mixture of oxygen and an inert gas, and may be selected as air.

[0015] In some embodiments, the heat treatment temperature is 200-250°C, and the heat treatment time is 10-30 minutes.

[0016] In some embodiments, the surface of the medical zirconium-niobium alloy after pre-oxidation treatment has a pre-oxidation layer.

[0017] In some embodiments, the pre-oxidized layer comprises monoclinic ZrO2.

[0018] In some embodiments, the thickness of the pre-oxidized layer is 20-50 nm.

[0019] In some embodiments, the complexing dissolution includes: subjecting the acid-washed medical zirconium-niobium alloy to a first impregnation treatment in a complexing agent solution.

[0020] In some embodiments, the complexing agent solution comprises a complexing agent and a solvent, wherein the complexing agent comprises at least one of citric acid and disodium ethylenediaminetetraacetate, and the solvent comprises water.

[0021] In some embodiments, the citric acid content in the complexing agent solution is 8-12% by mass.

[0022] In some embodiments, the disodium ethylenediaminetetraacetate in the complexing agent solution contains 2-4% by mass.

[0023] In some embodiments, the complexing agent solution is composed of citric acid (C6H8O7), disodium ethylenediaminetetraacetate (EDTA-2Na), and the solvent, wherein the solvent is ultrapure water.

[0024] In some embodiments, the pH of the complexing agent solution is 4.0-5.0.

[0025] In some embodiments, the temperature of the first impregnation treatment is 50-55°C.

[0026] In some embodiments, the first immersion treatment takes 8-12 minutes.

[0027] In some embodiments, the first impregnation process is accompanied by ultrasonic dispersion.

[0028] In some embodiments, the ultrasonic dispersion power is 300-400W, and the ultrasonic dispersion frequency is 35-45kHz.

[0029] In some embodiments, the surface roughness of the medical zirconium-niobium alloy after pickling is controlled to be 0.3-0.5 μm.

[0030] In some embodiments, the pickling solution used for pickling includes 35-45 wt% hydrofluoric acid, 65-68 wt% nitric acid and water, and the volume ratio of the 35-45 wt% hydrofluoric acid, the 65-68 wt% nitric acid and the water is (2-4):(30-35):(61-68); optionally, the water is ultrapure water.

[0031] In some embodiments, the pickling temperature is 30-35°C.

[0032] In some embodiments, the pickling time is 2-5 minutes.

[0033] In some embodiments, the pickling is carried out under stirring conditions, and the stirring speed is 50-80 r / min.

[0034] In some embodiments, the pickling method includes immersion pickling.

[0035] In some embodiments, the surface activation treatment includes: subjecting the medical zirconium-niobium alloy, after complexation and dissolution, to a second immersion treatment in an activation solution.

[0036] In some embodiments, the activation solution comprises 65-68 wt% nitric acid and ultrapure water, and the 65-68 wt% nitric acid in the activation solution has a mass content of 2-3%.

[0037] In some embodiments, the second impregnation treatment is a static impregnation treatment.

[0038] In some embodiments, the temperature of the second impregnation treatment is 25-30°C.

[0039] In some embodiments, the second impregnation treatment takes 2-3 minutes.

[0040] In some embodiments, the surface activation treatment further includes a first cleaning performed before the second immersion treatment and a second cleaning performed after the second immersion treatment.

[0041] In some embodiments, the first cleaning is performed by rinsing with ultrapure water, and the second cleaning is performed by rinsing with ultrapure water.

[0042] In some embodiments, the pre-oxidation treatment, the pickling, the complexation dissolution, and the surface activation treatment are performed sequentially.

[0043] In some embodiments, the surface treatment method for the medical zirconium-niobium alloy further includes at least one of the following steps: A pretreatment step is included before the pre-oxidation treatment. The washing and drying steps are provided after the surface activation treatment.

[0044] In some embodiments, the pretreatment step includes: mechanically polishing, degreasing and cleaning the medical zirconium-niobium alloy and washing it with water.

[0045] In some embodiments, the mechanical polishing is performed using 320-1000 grit SiC sandpaper, and the surface roughness of the medical zirconium-niobium alloy after polishing is below 0.6 μm.

[0046] In some embodiments, the degreasing cleaning is performed using analytical grade anhydrous ethanol for ultrasonic cleaning, wherein the ultrasonic cleaning power is 200-300W and the ultrasonic cleaning time is 3-6 minutes.

[0047] In some embodiments, the washing and drying steps include: boiling, rinsing and drying the surface-activated medical zirconium-niobium alloy.

[0048] In some embodiments, the detergents used in the washing and drying steps, including boiling and rinsing, all include ultrapure water.

[0049] In some embodiments, during the washing and drying steps, the boiling temperature is 80-85°C and the boiling time is 5-8 minutes.

[0050] In some embodiments, the washing and drying steps include vacuum drying, the drying temperature is 60-70°C, and the drying time is 30-40 minutes.

[0051] In some embodiments, the medical zirconium-niobium alloy comprises a Zr-2.5Nb-0.1O alloy.

[0052] In some embodiments, the medical zirconium-niobium alloy is in the form of at least one of rods and plates.

[0053] In some embodiments, the surface treatment method for the medical zirconium-niobium alloy is the surface treatment method for the medical zirconium-niobium alloy before high-temperature oxidation.

[0054] The second aspect of this application relates to the application of the surface treatment method for medical zirconium-niobium alloys described in the first aspect of this application in the surface treatment process before high-temperature oxidation of medical zirconium-niobium alloys.

[0055] The surface treatment method for medical zirconium-niobium alloys described in this application can bring at least the following beneficial effects: 1. A composite treatment mechanism of "pre-oxidation buffer - gentle acid washing - complexation chemical dissolution of SPP - surface activation" is adopted to chemically dissolve SPP at its source, completely avoiding the residue problems that may be caused by the physical shedding of SPP in related technologies. Furthermore, the entire process avoids biocompatibility risks such as oxalates, achieving perfect compatibility with subsequent high-temperature oxidation processes. Specifically: Pre-oxidation treatment forms a pre-oxidized layer on the surface of zirconium-niobium alloys such as Zr-2.5Nb-0.1O bars. This pre-oxidized layer can act as a "sacrificial layer" to uniformly consume the pickling solution in the subsequent pickling process, avoiding excessively rapid local dissolution of the Zr matrix in the early stage of pickling. This inhibits the severe exposure and peeling of SPP caused by rapid matrix dissolution from the source, making the pickling process more uniform and controllable.

[0056] Pickling, combined with the aforementioned pre-oxidized layer, can synergistically control the dissolution rate of the Zr matrix, thereby reducing the generation of SPP at the source and obtaining a bright, uniform, and controllable macroscopic surface, laying the foundation for subsequent processing.

[0057] Complexation dissolution directly dissolves SPP chemically, rather than physically causing it to detach.

[0058] Surface activation treatment can remove trace amounts of surface adsorbates or residues.

[0059] 2. The nitric acid used in the pickling and surface activation processes, the citric acid used in the complexing and dissolving processes, and the dissolving agent ethylenediaminetetraacetic acid disodium salt are all chemical reagents or their decomposition products that have good biocompatibility or are easy to thoroughly clean.

[0060] 3. The complexation and dissolution process uses citric acid and disodium EDTA as complexing agents, which clearly avoids the use of oxalic acid or ammonium oxalate in related technologies, eliminating the potential risk of oxalate residues on the surface of medical implants and fully meeting the stringent biosafety requirements for medical implant materials.

[0061] 4. By buffering the acid pickling with the pre-oxidation layer, synergistically controlling the mild acid pickling parameters, and finally performing surface activation treatment, this method can precisely control the final surface roughness (Ra 0.3-0.5μm) and chemical state, providing a perfect substrate for the subsequent high-temperature oxidation to prepare a dense, stable, and strongly bonded biocompatible oxide film, ensuring the long-term safety and reliability of medical devices.

[0062] 5. This method has a clear operation process, well-defined parameters for each step, and strong controllability. No mechanical wiping is required throughout the process, avoiding physical damage. It is particularly suitable for slender bars and complex-shaped workpieces, and has promising prospects for industrial applications.

[0063] It should be noted that the surface treatment method for medical zirconium-niobium alloys described in this application differs fundamentally from the surface treatment processes for zirconium alloys and other alloys in related technologies. Firstly, regarding the target material, most related technologies focus on common engineering materials such as carbon steel or aluminum alloys, and the treatment of zirconium alloys is primarily concentrated on nuclear power zirconium alloys. This application, however, specifically targets medical zirconium-niobium alloys, which are used in implantable medical devices due to their biocompatibility, thus requiring more stringent surface treatment. Secondly, regarding the process objective, the core of related technologies is to provide a clean surface for subsequent application of external coatings (such as zinc layers, organic powder coatings, or aluminum / ceramic composite coatings) to improve adhesion or wear resistance. The purpose of this application, however, is to provide a clean substrate for subsequent high-temperature oxidation to generate a biocompatible oxide film homologous to the substrate, with the treated surface directly participating in the oxidation reaction. Finally, this application innovatively adopts a composite treatment mechanism of "pre-oxidation buffer - mild pickling - citric acid / EDTA complexation chemical dissolution of SPP - surface activation" to chemically dissolve SPP from the source, completely avoiding the residual problems that may be caused by the physical shedding of SPP in related technologies, and avoiding biocompatibility risk substances such as oxalate throughout the process, achieving perfect matching with the subsequent high-temperature oxidation process.

[0064] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0065] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings. in: Figure 1 The image shows the end face of a Zr-2.5Nb-0.1O alloy bar after surface treatment using the medical zirconium-niobium alloy surface treatment method described in Example 1.

[0066] Figure 2 Photographs of the appearance of Zr-2.5Nb-0.1O alloy rods after oxidation following surface treatment using the medical zirconium-niobium alloy surface treatment method of Example 1. Detailed Implementation

[0067] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0068] In this application, the disclosure of numerical ranges includes all values ​​throughout the range and the disclosure of further subdivisions of the range, including the endpoints and subranges given for these ranges.

[0069] Unless otherwise specified, all raw materials and equipment involved in this application are self-made through commercial means or known methods; and all methods involved are conventional methods unless otherwise specified.

[0070] When the term “and / or” is used in a list containing two or more items, it means that any of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression “A and / or B” is intended to mean A or B or A and B, that is, A only, B only, or a combination of A and B.

[0071] In this application, room temperature refers to 20-30℃.

[0072] To address the limitations of acid pickling processes in the application of zirconium-niobium alloys, such as medical-grade Zr-2.5Nb-0.1O alloy rods, this application develops a multi-step, synergistic high-temperature pre-oxidation surface treatment method—a surface treatment method for medical-grade zirconium-niobium alloys. This method solves the problems of incomplete cleaning, surface damage, residual acid affecting oxide film quality, and incompatibility with biocompatibility requirements in medical materials caused by acid pickling methods. This surface treatment method for medical-grade zirconium-niobium alloys involves multiple steps, including pre-oxidation, acid pickling, complexation dissolution, and surface activation. By precisely controlling the surface treatment process parameters and synergistically processing these steps, the method achieves thorough removal of impurities from the alloy rod surface, resulting in a uniform, clean, and undamaged surface. This ensures a high-quality, biocompatible oxide film for subsequent high-temperature oxidation, guaranteeing the safety and reliability of medical-grade Zr-2.5Nb-0.1O alloy rods and other zirconium-niobium alloys in clinical use.

[0073] The surface treatment method for medical zirconium-niobium alloy according to the present application includes: pre-oxidation treatment, pickling, complexation dissolution and surface activation treatment of the medical zirconium-niobium alloy.

[0074] For example, in the Zr-2.5Nb-0.1O alloy: the mass content of Nb is 1-5%, including but not limited to 2%, 3% or 4%; the mass content of O is 0.05-0.15%, including but not limited to 0.07%, 0.1% or 0.13%; and the mass content of Fe is 0.01-0.15%, including but not limited to 0.05%, 0.1% or 0.13%.

[0075] It should be noted that in the Zr-2.5Nb-0.1O alloy, in addition to the Nb, O and Fe elements mentioned above, the balance is Zr element or Zr element and unavoidable impurities.

[0076] In some embodiments, the medical zirconium-niobium alloy may be in the form of at least one of rods, plates, or other shapes, and may be selected as rods.

[0077] As an optional example, the medical zirconium-niobium alloy is a Zr-2.5Nb-0.1O alloy rod.

[0078] In some embodiments, the pre-oxidation treatment, the pickling, the complexation dissolution, and the surface activation treatment are performed sequentially.

[0079] In some embodiments, the surface treatment method for the medical zirconium-niobium alloy further includes at least one of the following steps: A pretreatment step is included before the pre-oxidation treatment. The washing and drying steps are provided after the surface activation treatment.

[0080] As an optional example, the surface treatment method of the medical zirconium-niobium alloy includes: sequentially performing pretreatment, pre-oxidation treatment, pickling, complexation dissolution, surface activation treatment, washing, and drying on the medical zirconium-niobium alloy.

[0081] The following details each step of the surface treatment method for medical zirconium-niobium alloys according to embodiments of this application.

[0082] [Preprocessing] In the embodiments of this application, the purpose of pretreatment is to remove macroscopic impurities, oil stains and dust from the surface of the medical zirconium-niobium alloy.

[0083] In some embodiments, the pretreatment step includes: mechanically polishing, degreasing and cleaning the medical zirconium-niobium alloy and washing it with water.

[0084] In some embodiments, the mechanical polishing is performed using SiC sandpaper of 320-1000 grit (e.g., 400 grit, 500 grit, 600 grit, 700 grit, or 800 grit, etc.), and the surface roughness of the medical zirconium-niobium alloy after polishing is below 0.6 μm, for example, below 0.5 μm.

[0085] It should be noted that when the medical zirconium-niobium alloy is a Zr-2.5Nb-0.1O alloy rod, mechanical polishing is performed by uniformly polishing the alloy rod circumferentially with 320-1000 grit SiC sandpaper.

[0086] In some embodiments, the degreasing cleaning is performed using analytical grade anhydrous ethanol for ultrasonic cleaning.

[0087] For example, during the degreasing and cleaning process, the power of the ultrasonic cleaning is 200-300W, including but not limited to 220W, 250W or 275W.

[0088] For example, during the degreasing and cleaning process, the ultrasonic cleaning time is 3-6 minutes, including but not limited to 4 minutes or 5 minutes.

[0089] In the embodiments of this application, the purpose of water washing during the pretreatment process is to ensure that there is no anhydrous ethanol residue on the surface of the medical zirconium-niobium alloy after degreasing and cleaning.

[0090] In some embodiments, the water washing method includes: first rinsing with running tap water for 3-5 minutes (e.g., 4 minutes), and then rinsing with ultrapure water 2-3 times (e.g., 2 times).

[0091] [Pre-oxidation treatment] In the embodiments of this application, the pre-oxidation treatment is used to form a pre-oxidation layer on the surface of zirconium-niobium alloys such as Zr-2.5Nb-0.1O rods. This pre-oxidation layer can act as a "sacrificial layer" to uniformly consume the pickling solution in the subsequent pickling process, thereby preventing the local rapid dissolution of the Zr matrix in the early stage of pickling. This inhibits the severe exposure and peeling of SPP caused by rapid dissolution of the matrix from the source, making the pickling process more uniform and controllable.

[0092] In some embodiments, the pre-oxidation treatment includes: heat-treating the medical zirconium-niobium alloy in an oxidizing gas atmosphere.

[0093] In some embodiments, the oxidizing gas includes, but is not limited to, at least one of air, oxygen, or a mixture of oxygen and inert gases, and may be selected as air.

[0094] For example, the volume fraction of oxygen in the mixture of oxygen and inert gas is 20% or more, including but not limited to 30% or more, 40% or more, or 50% or more.

[0095] As an optional example, the heat treatment is carried out in an air atmosphere oven.

[0096] In some embodiments, the heat treatment temperature is 200-250°C, and the heat treatment time is 10-30 minutes.

[0097] For example, the temperature of the heat treatment includes, but is not limited to, 210°C, 220°C, 230°C or 240°C.

[0098] For example, the heat treatment time includes, but is not limited to, 11 min, 12 min, 13 min, 14 min, 15 min, 17 min, 20 min, 23 min, 26 min or 29 min, and can be selected as 10-15 min.

[0099] In some embodiments, the surface of the medical zirconium-niobium alloy after pre-oxidation treatment has a pre-oxidation layer. The pre-oxidation layer serves to buffer subsequent pickling processes.

[0100] In some embodiments, the thickness of the pre-oxidized layer is 20-50 nm, including but not limited to 30 nm or 40 nm.

[0101] In some embodiments, the pre-oxidized layer comprises monoclinic zirconium dioxide (ZrO2).

[0102] In the lithium embodiments of this application, the pre-oxidized layer is mainly a dense monoclinic ZrO2 phase. Since the dissolution rate of ZrO2 in HF acid is much lower than that of metallic Zr, this layer can act as a "sacrificial layer" to uniformly consume the acid, preventing excessively rapid local dissolution of the Zr matrix in the initial stage of pickling. This suppresses the severe exposure and detachment of SPP caused by rapid matrix dissolution, making the pickling process more uniform and controllable. Furthermore, by controlling the heat treatment temperature to 200-250℃ and the heat treatment time to 10-30 min, the thickness of the pre-oxidized layer can be controlled to 20-50 nm, thereby better achieving the aforementioned functions.

[0103] [Pickling] In the embodiments of this application, the pickling is a mild, single pickling.

[0104] In some embodiments, the pickling solution used for pickling includes 35-45 wt% hydrofluoric acid (e.g., 40 wt% hydrofluoric acid, etc.), 65-68 wt% nitric acid, and water.

[0105] For example, the water in the pickling solution includes, but is not limited to, ultrapure water, deionized water, etc., and ultrapure water can be selected.

[0106] For example, the volume ratio of the 35-45 wt% hydrofluoric acid, the 65-68 wt% nitric acid, and the water is (2-4):(30-35):(61-68), including but not limited to 3:33:64, 2:30:68, 4:35:61, 2:35:63, 4:30:66, or 2:33:65.

[0107] In some embodiments, the pickling temperature is 30-35°C, including but not limited to 31°C, 32°C, 33°C or 34°C.

[0108] In some embodiments, the pickling time is 2-5 minutes, including but not limited to 3 minutes or 4 minutes.

[0109] In some embodiments, the pickling is carried out under stirring conditions, and the stirring speed is 50-80 r / min, including but not limited to 60 r / min or 70 r / min.

[0110] In some embodiments, the pickling method includes immersion pickling.

[0111] As an optional example, the pickling includes: The pre-oxidized medical zirconium-niobium alloy is immersed in pickling solution, and the pickling temperature is controlled at 30-35℃ for 2-5 minutes, during which it is slowly stirred at a speed of 50-80 r / min.

[0112] Compared to traditional high-concentration, long-term pickling, the embodiments of this application use relatively mild pickling parameters, combined with the pre-oxidized layer formed by the pre-oxidation process, which can synergistically control the dissolution rate of the Zr matrix, reduce the generation of SPP from the source, and obtain a macroscopic surface with a bright, uniform surface and controllable roughness (Ra 0.3-0.5μm), laying the foundation for subsequent processing.

[0113] [Complex Dissolution] In the embodiments of this application, complexation dissolution directly dissolves SPP chemically, rather than physically causing it to detach.

[0114] In some embodiments, the complexing dissolution includes: subjecting the acid-washed medical zirconium-niobium alloy to a first impregnation treatment in a complexing agent solution.

[0115] In some embodiments, after pickling, the pickled medical-grade zirconium-niobium alloy needs to be immediately immersed in a complexing agent solution for a first immersion treatment. The purpose of this operation is to dissolve the SPP formed after pickling the zirconium-niobium alloy.

[0116] In some embodiments, the complexing agent solution includes a complexing agent and a solvent. The complexing agent includes, but is not limited to, at least one of citric acid (C6H8O7), disodium ethylenediaminetetraacetate (EDTA-2Na), etc.; the solvent includes water, such as ultrapure water.

[0117] In some embodiments, the citric acid in the complexing agent solution has a mass content of 8-12%, including but not limited to 8.5%, 9%, 9.5%, 10%, 10.5%, 11% or 11.5%.

[0118] In the embodiments of this application, the mass content of citric acid in the complexing agent solution is controlled to be 8-12%, which can effectively remove surface SPP; below 8%, the removal effect is not good; above 12%, it will cause slight etching on the zirconium-niobium alloy surface.

[0119] In some embodiments, the disodium ethylenediaminetetraacetate in the complexing agent solution has a mass content of 2-4%, including but not limited to 2.25%, 2.5%, 2.75%, 3%, 3.25%, 3.5%, or 3.75%.

[0120] As an alternative example, the complexing agent consists of citric acid and disodium ethylenediaminetetraacetate, whose synergistic complexing effect can better and more directly dissolve niobium-rich secondary phase particles. As an optional example, the complexing agent solution comprises citric acid (C6H8O7), disodium ethylenediaminetetraacetate (EDTA-2Na), and the solvent, wherein the solvent is ultrapure water. Further optionally, the complexing agent solution comprises the following components in the following mass percentages: 8-12% citric acid, 2-4% disodium ethylenediaminetetraacetate, and the balance being ultrapure water.

[0121] In some embodiments, the pH of the complexing agent solution is 4.0-5.0, such as 4.2, 4.5 or 4.8.

[0122] As an optional example, the complexing agent solution is prepared by mixing citric acid, disodium ethylenediaminetetraacetate and ultrapure water in the prescribed amounts, and then adjusting the pH to 4.0-5.0 with a dilute NaOH solution (e.g., 1-10 wt% NaOH solution).

[0123] In some embodiments, the temperature of the first impregnation treatment is 50-55°C, including but not limited to 51°C, 52°C, 53°C or 54°C.

[0124] In some embodiments, the first immersion treatment time is 8-12 minutes, including but not limited to 9 minutes, 10 minutes or 11 minutes.

[0125] In some embodiments, the first impregnation treatment is accompanied by ultrasonic dispersion. The use of ultrasonic-assisted treatment in the first impregnation treatment can enhance mass transfer and reaction efficiency.

[0126] In some embodiments, the power of the ultrasonic dispersion accompanying the first impregnation treatment is 300-400W, including but not limited to 320W, 350W or 375W.

[0127] In some embodiments, the frequency of the ultrasonic dispersion accompanying the first impregnation treatment is 35-45 kHz, including but not limited to 37 kHz, 40 kHz or 43 kHz.

[0128] In the embodiments of this application, the strong complexing ability of citric acid and EDTA for Nb ions is utilized to form stable soluble complexes with the Nb element in SPP (mainly containing Nb), thereby achieving the chemical dissolution of SPP. This method avoids the risk of SPP detachment and re-adsorption in the oxalic acid method, fundamentally eliminating the source of "black powder," and resulting in a clean and flawless surface after treatment.

[0129] [Surface activation treatment] In the embodiments of this application, surface activation treatment can remove trace amounts of surface adsorbates or residues.

[0130] In some embodiments, the surface activation treatment includes: subjecting the medical zirconium-niobium alloy, after complexation and dissolution, to a second immersion treatment in an activation solution.

[0131] In some embodiments, the activation solution comprises 65-68 wt% nitric acid and ultrapure water.

[0132] As an alternative example, the activation solution consists of 65-68 wt% nitric acid and ultrapure water.

[0133] In some embodiments, the 65-68 wt% nitric acid in the activation solution has a mass content of 2-3%, including but not limited to 2.2%, 2.5% or 2.7%.

[0134] It should be noted that when the activation solution consists of 65-68 wt% nitric acid and ultrapure water, the 65-68 wt% nitric acid content in the activation solution is 2-3% by mass, and the balance is ultrapure water (that is, the ultrapure water content in the activation solution is 97-98% by mass). Treatment with a 2-3% extremely dilute nitric acid solution forms a uniform and dense nanoscale passivation film on the surface.

[0135] In some embodiments, the second impregnation treatment is a static impregnation treatment (i.e., a static soaking treatment).

[0136] In some embodiments, the temperature of the second impregnation treatment is 25-30°C, including but not limited to 26°C, 27°C, 28°C or 29°C.

[0137] In some embodiments, the processing time for the second impregnation treatment is 2-3 minutes, including but not limited to 2.2 minutes, 2.5 minutes or 2.8 minutes.

[0138] In the embodiments of this application, the medical zirconium-niobium alloy after complexation and dissolution is subjected to a second immersion treatment with an activation solution containing 2-3 wt% 65-68 wt% nitric acid during the surface activation process. The purpose is to remove trace amounts of surface adsorbates or residues, while simultaneously utilizing the passivation effect of low-concentration nitric acid on Zr to form an extremely thin, uniform, and dense passivation film (approximately 1-2 nm thick) in situ on the surface. This passivation film neither hinders subsequent high-temperature oxidation (which would reconstruct and integrate into the oxide layer at high temperatures) nor prevents recontamination of the treated surface in the air, thus preparing a chemically stable, clean, and activated surface state for high-temperature oxidation. Controlling the temperature of the second immersion treatment to 25-30°C and the treatment time to 2-3 minutes further enhances the achievement of these objectives.

[0139] In some embodiments, in order to remove the complexing agent solution remaining on the surface of the medical zirconium-niobium alloy after complexation and dissolution, the surface activation treatment further includes a first cleaning performed before the second immersion treatment.

[0140] For example, the first cleaning uses ultrapure water rinsing, which can be done multiple times, such as 2-3 times.

[0141] In some embodiments, to ensure that there is no nitric acid residue on the surface of the medical zirconium-niobium alloy after the second impregnation treatment, the surface activation treatment further includes a second cleaning performed after the second impregnation treatment.

[0142] For example, the second cleaning uses ultrapure water rinsing, which can be done multiple times, for example, 3 times, each time for 30 seconds.

[0143] It should be noted that the medical zirconium-niobium alloy after the second impregnation treatment should be rinsed with ultrapure water immediately after the second impregnation treatment.

[0144] [Washing and drying] In the embodiments of this application, the purpose of washing the surface-activated medical zirconium-niobium alloy is to thoroughly remove trace amounts of physical adsorbates from the surface.

[0145] In some embodiments, the washing and drying steps include: boiling, rinsing and drying the surface-activated medical zirconium-niobium alloy.

[0146] In some embodiments, the detergents used in the washing and drying steps, including boiling and rinsing, all include ultrapure water.

[0147] In some embodiments, during the washing and drying steps, the boiling temperature is 80-85°C and the boiling time is 5-8 minutes.

[0148] For example, the boiling temperature includes, but is not limited to, 81°C, 82°C, 83°C, or 84°C.

[0149] For example, the boiling time includes, but is not limited to, 6 minutes or 7 minutes.

[0150] In some embodiments, the rinsing step in the washing and drying process is performed at room temperature.

[0151] In some embodiments, the drying method in the washing and drying steps includes vacuum drying.

[0152] In some embodiments, the drying temperature is 60-70°C, including but not limited to 62°C, 65°C, or 68°C. Maintaining a drying temperature within this range avoids excessively high temperatures that could lead to natural surface oxidation, ensuring the dried surface remains in an optimal activated state.

[0153] In some embodiments, the drying time is 30-40 minutes, including but not limited to 32 minutes, 34 minutes, 36 minutes or 38 minutes.

[0154] As an optional example, the surface treatment method for the medical zirconium-niobium alloy is the surface treatment method for the medical zirconium-niobium alloy before high-temperature oxidation.

[0155] For example, the high-temperature oxidation temperature is 500-700℃, including but not limited to 550℃, 600℃ or 650℃; the high-temperature oxidation is carried out in a gaseous atmosphere such as air or oxygen.

[0156] The surface treatment method for medical zirconium-niobium alloys in this application can be widely used for surface treatment of medical zirconium-niobium alloys before high-temperature oxidation, and therefore has at least the beneficial effects of the surface treatment method for medical zirconium-niobium alloys in this application.

[0157] The following non-limiting embodiments further illustrate certain features of the present technology.

[0158] Example 1 This embodiment provides a surface treatment method for medical zirconium-niobium alloy, wherein the medical zirconium-niobium alloy is a Zr-2.5Nb-0.1O alloy rod (chemical composition: Nb: 2.7wt%; O: 0.1wt%; Fe: 0.1wt%; balance is Zr and unavoidable impurities). The surface treatment method for this medical zirconium-niobium alloy is a surface treatment method before high-temperature oxidation, including the following steps: Step 1: Pretreatment. The medical-grade Zr-2.5Nb-0.1O alloy rods are subjected to mechanical grinding, degreasing and cleaning, and water washing in sequence to obtain pretreated medical-grade Zr-2.5Nb-0.1O alloy rods.

[0159] Mechanical polishing involves uniformly polishing the alloy rod along its axial direction using 320-1000 grit SiC sandpaper, resulting in a surface roughness of 0.25 μm. Degreasing and cleaning are performed using analytical grade anhydrous ethanol with ultrasonic cleaning at a power of 250 W for 4.5 min. Water washing involves rinsing with running tap water for 4 min, followed by rinsing three times with ultrapure water.

[0160] Step 2: Pre-oxidation treatment. The pre-treated Zr-2.5Nb-0.1O alloy rod is placed in an air atmosphere oven and heated to 225℃ for 20 minutes. A pre-oxidation layer with a thickness of 7.5nm is formed on the surface of the pre-treated Zr-2.5Nb-0.1O alloy rod, thus obtaining the pre-oxidized Zr-2.5Nb-0.1O alloy rod.

[0161] The pre-oxidized layer was found to be composed of a dense ZrO2 film, as determined by scanning electron microscopy and energy dispersive spectroscopy (SEM+EDS).

[0162] Step 3: Gentle single pickling. Immerse the pre-oxidized Zr-2.5Nb-0.1O alloy rods in the pickling solution, control the pickling temperature at 32℃, and the pickling time at 3.5min. During the pickling process, stir slowly at a speed of 65r / min. After pickling, the pickled Zr-2.5Nb-0.1O alloy rods are obtained.

[0163] The pickling solution was prepared by mixing 40wt% hydrofluoric acid, 68% nitric acid (commercially available concentrated nitric acid), and ultrapure water in a volume ratio of 3:32.5:64.5. The surface roughness of the pickled Zr-2.5Nb-0.1O alloy rod was measured to be 0.20μm using a roughness tester.

[0164] Step 4: Complexation and Dissolution. The acid-washed Zr-2.5Nb-0.1O alloy rods are immediately immersed in a complexing agent solution. The treatment temperature is controlled at 52.5℃ and the treatment time is 10 minutes. During the treatment, ultrasonic treatment with a power of 350W and a frequency of 40kHz is used to assist the treatment. After treatment, Zr-2.5Nb-0.1O alloy rods with complexation and dissolution are obtained.

[0165] in, The complexing agent solution consists of the following components in the indicated mass percentages: 10% citric acid (C6H8O7), 3% EDTA-2Na (disodium ethylenediaminetetraacetate), and the balance being ultrapure water; the pH of the complexing agent solution is 4.5.

[0166] The method for preparing the complexing agent solution is as follows: after mixing the prescribed amounts of citric acid, EDTA-2Na and ultrapure water, adjust the pH to 4.5 with 5.5wt% NaOH solution.

[0167] Step 5: Surface activation treatment. The Zr-2.5Nb-0.1O alloy rods after complexation and dissolution are thoroughly rinsed three times with ultrapure water, and then immersed in the activation solution using a static immersion method. The immersion temperature is controlled at 28℃, and the immersion time is 2.5 minutes. Immediately after immersion, the rods are rinsed three times with ultrapure water for 30 seconds each time, resulting in surface-activated Zr-2.5Nb-0.1O alloy rods.

[0168] in, The activation solution comprises the following components by mass percentage: 2.5% nitric acid (commercially available concentrated nitric acid) at a concentration of 68 wt%, and 97.5% ultrapure water.

[0169] The activation solution is prepared by mixing 68wt% nitric acid and ultrapure water according to the formula.

[0170] Step Six: Boiling and Drying. The surface-activated Zr-2.5Nb-0.1O alloy rods were boiled in 82℃ ultrapure water for 6.5 min, followed by rinsing twice with room temperature (25℃) ultrapure water. Finally, the rods were placed in a vacuum drying oven and dried at 65℃ for 35 min to obtain the surface-treated Zr-2.5Nb-0.1O alloy rods.

[0171] Figure 1 The image shows the end face appearance of a Zr-2.5Nb-0.1O alloy rod after surface treatment using the medical zirconium-niobium alloy surface treatment method described in Example 1. From... Figure 1 It can be seen that after treatment, the surface of the zirconium-niobium alloy has a uniform metallic luster and no defects such as local color difference or water pitting.

[0172] Figure 2 The image shows the appearance of the rear end face of a Zr-2.5Nb-0.1O alloy rod after oxidation at 600°C for 1 hour in air atmosphere following the surface treatment method of medical zirconium-niobium alloy in Example 1. Figure 1 As can be seen, the zirconium oxide film obtained after high-temperature oxidation of Zr-2.5Nb-0.1O alloy rods treated with the surface treatment method of medical zirconium-niobium alloy of this application exhibits a uniform black and glossy appearance, without local color differences, white spots or other oxidation defects.

[0173] Example 2 This embodiment is basically the same as embodiment 1, except that: In step two, the temperature is raised to 200°C and held for 30 minutes; the thickness of the pre-oxidized layer formed is 5 nm.

[0174] In step three, the surface roughness of the pickled Zr-2.5Nb-0.1O alloy bar is 0.23μm.

[0175] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0176] Example 3 This embodiment is basically the same as embodiment 1, except that: In step two, the temperature is raised to 250°C and held for 10 minutes; the thickness of the pre-oxidized layer formed is 10 nm.

[0177] In step three, the surface roughness of the pickled Zr-2.5Nb-0.1O alloy bar is 0.20μm.

[0178] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0179] Example 4 This embodiment is basically the same as embodiment 1, except that: In step three, the pickling solution is prepared by mixing 40wt% hydrofluoric acid, 68% nitric acid (commercially available concentrated nitric acid) and ultrapure water in a volume ratio of 4:30:66; the surface roughness of the Zr-2.5Nb-0.1O alloy rod after pickling is 0.18μm.

[0180] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0181] Example 5 This embodiment is basically the same as embodiment 1, except that: In step three, the pickling solution is prepared by mixing 40wt% hydrofluoric acid, 68% nitric acid (commercially available concentrated nitric acid) and ultrapure water in a volume ratio of 2:35:63; the surface roughness of the Zr-2.5Nb-0.1O alloy rod after pickling is 0.18μm.

[0182] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0183] Example 6 This embodiment is basically the same as embodiment 1, except that: In step three, the pickling temperature is controlled at 30℃ and the pickling time is 5min; the surface roughness of the Zr-2.5Nb-0.1O alloy bar after pickling is 0.15μm.

[0184] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0185] Example 7 This embodiment is basically the same as embodiment 1, except that: In step three, the pickling temperature is controlled at 35℃ and the pickling time is 2min; the surface roughness of the Zr-2.5Nb-0.1O alloy bar after pickling is 0.15μm.

[0186] In step five, a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0187] Example 8 This embodiment is basically the same as embodiment 1, except that: In step four, the complexing agent solution is composed of the following components by mass percentage: 12% citric acid (C6H8O7), 2% EDTA-2Na (disodium ethylenediaminetetraacetate), and the balance being ultrapure water; the pH of the complexing agent solution is 4.3; the pH is adjusted to 4.3 in the preparation method of the complexing agent solution.

[0188] Example 9 This embodiment is basically the same as embodiment 1, except that: In step four, the complexing agent solution is composed of the following components by mass percentage: 8% citric acid (C6H8O7), 4% EDTA-2Na (disodium ethylenediaminetetraacetate), and the balance being ultrapure water; the pH of the complexing agent solution is 4.3; the pH is adjusted to 4.3 in the preparation method of the complexing agent solution.

[0189] Example 10 This embodiment is basically the same as embodiment 1, except that: In step four: The processing temperature was controlled at 50℃, and the processing time was 12 minutes. The power of the ultrasonic-assisted processing is 300W; The complexing agent solution is composed of the following components in the indicated mass percentages: 12% citric acid (C6H8O7), 4% EDTA-2Na (disodium ethylenediaminetetraacetate), and the balance being ultrapure water; the pH of the complexing agent solution is 4.1; the pH is adjusted to 4.1 in the preparation method of the complexing agent solution.

[0190] Example 11 This embodiment is basically the same as embodiment 1, except that: In step four: The processing temperature was controlled at 55℃, and the processing time was 8 minutes. The power of the ultrasonic-assisted processing is 400W; The complexing agent solution is composed of the following components in the indicated mass percentages: 8% citric acid (C6H8O7), 2% EDTA-2Na (disodium ethylenediaminetetraacetate), and the balance being ultrapure water; the pH of the complexing agent solution is 4.4; the pH is adjusted to 4.4 in the preparation method of the complexing agent solution.

[0191] Example 12 This embodiment is basically the same as embodiment 1, except that: In step five, the activation solution includes the following components by mass percentage: 2% nitric acid at a concentration of 65wt%, and 98% ultrapure water; a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0192] Example 13 This embodiment is basically the same as embodiment 1, except that: In step five, the activation solution includes the following components by mass percentage: 3% 68wt% nitric acid (commercially available concentrated nitric acid), 97% ultrapure water; a bright surface is formed on the surface of the Zr-2.5Nb-0.1O alloy rod after complexation and dissolution.

[0193] Comparative Example 1 This comparative example is basically the same as Example 1, except that: Step two is excluded. In step three, the pretreated Zr-2.5Nb-0.1O alloy rods are directly immersed in the pickling solution.

[0194] Comparative Example 2 This comparative example is basically the same as Example 1, except that: Excluding step three, in step four, the pre-oxidized Zr-2.5Nb-0.1O alloy rod is immediately immersed in the complexing agent solution.

[0195] Comparative Example 3 This comparative example is basically the same as Example 1, except that: Excluding step four, step five directly involves surface activation treatment of the pickled Zr-2.5Nb-0.1O alloy rod.

[0196] Comparative Example 4 This comparative example is basically the same as Example 1, except that: Excluding step five, step six involves directly boiling and drying the Zr-2.5Nb-0.1O alloy rods after complexation and dissolution.

[0197] Comparative Example 5 This comparative example provides a surface treatment method for a medical zirconium-niobium alloy, wherein the medical zirconium-niobium alloy is a Zr-2.5Nb-0.1O alloy rod (chemical composition: Nb: 2.7wt%; O: 0.1wt%; Fe: 0.1wt%; balance Zr and unavoidable impurities). The surface treatment method for this medical zirconium-niobium alloy is a surface treatment method before high-temperature oxidation, including the following steps: (1) The medical zirconium-niobium alloy Zr-2.5Nb-0.1O alloy rod was immersed in an acid pickling solution composed of 40wt% commercially available concentrated nitric acid (i.e., 68wt% nitric acid) and 5wt% concentrated hydrofluoric acid (i.e., 40wt% hydrofluoric acid) for 20 minutes to obtain the acid-pickled medical zirconium-niobium alloy Zr-2.5Nb-0.1O alloy rod.

[0198] (2) The pickled medical zirconium-niobium alloy Zr-2.5Nb-0.1O alloy rods were placed at an ambient temperature of 26°C. A solution of 3.5wt% oxalic acid and 5wt% commercially available concentrated nitric acid (i.e., 68wt% nitric acid) was used as the washing solution, and then the rods were thoroughly rinsed in deionized water for 20 minutes to obtain the surface-treated Zr-2.5Nb-0.1O alloy rods.

[0199] In summary, the surface treatment method for medical zirconium-niobium alloys of this application, through multi-process collaborative processing and precise control of the process parameters of each step of the surface treatment, achieves complete removal of impurities from the surface of zirconium-niobium alloys such as Zr-2.5Nb-0.1O rods, obtaining a uniform, clean, and undamaged surface state. This provides a guarantee for the subsequent high-temperature oxidation to prepare a high-quality biocompatible oxide film, ensuring the safety and reliability of medical zirconium-niobium alloys such as Zr-2.5Nb-0.1O alloy rods in clinical use.

[0200] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0201] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0202] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A surface treatment method for a medical zirconium niobium alloy, characterized by, include: The medical zirconium-niobium alloy is subjected to pre-oxidation treatment, pickling, complexation dissolution and surface activation treatment.

2. The surface treatment method according to claim 1, characterized by, The pre-oxidation treatment includes: The medical zirconium-niobium alloy was heat-treated in an oxidizing gas atmosphere; And / or, the surface of the medical zirconium-niobium alloy after the pre-oxidation treatment has a pre-oxidation layer; And / or, the complexation dissolution includes: The pickled medical zirconium-niobium alloy is subjected to a first impregnation treatment in a complexing agent solution.

3. The surface treatment method according to claim 2, characterized by, The oxidizing gas includes at least one of air, oxygen, and a mixture of oxygen and an inert gas, and may be selected as air; And / or, the heat treatment temperature is 200-250°C, and the heat treatment time is 10-30 min; And / or, the pre-oxidized layer comprises monoclinic ZrO2; And / or, the thickness of the pre-oxidized layer is 20-50 nm.

4. The surface treatment method according to claim 2, characterized by, The complexing agent solution comprises a complexing agent and a solvent, wherein the complexing agent comprises at least one of citric acid and disodium ethylenediaminetetraacetate, and the solvent comprises water; And / or, the pH of the complexing agent solution is 4.0-5.0; And / or, the temperature of the first impregnation treatment is 50-55°C; And / or, the first immersion treatment time is 8-12 min; And / or, the first impregnation process is accompanied by ultrasonic dispersion.

5. The surface treatment method according to claim 4, wherein The citric acid content in the complexing agent solution is 8-12% by mass. And / or, the disodium ethylenediaminetetraacetate in the complexing agent solution contains 2-4% by mass; And / or, the complexing agent solution is composed of the citric acid, the disodium ethylenediaminetetraacetate, and the solvent, wherein the solvent is ultrapure water; And / or, the power of the ultrasonic dispersion is 300-400W, and the frequency of the ultrasonic dispersion is 35-45kHz.

6. The surface treatment method according to claim 1, characterized by, The surface roughness of the medical zirconium-niobium alloy after pickling is controlled to be 0.3-0.5 μm; And / or, the pickling solution used in the pickling comprises 35-45 wt% hydrofluoric acid, 65-68 wt% nitric acid and water, and the volume ratio of the 35-45 wt% hydrofluoric acid, the 65-68 wt% nitric acid and the water is (2-4):(30-35):(61-68); optionally, the water is ultrapure water; And / or, the pickling temperature is 30-35°C; And / or, the pickling time is 2-5 minutes; And / or, the pickling is carried out under stirring conditions, and the stirring speed is 50-80 r / min; And / or, the pickling method includes immersion pickling.

7. The surface treatment method according to any one of claims 1 to 6, characterized by, The pre-oxidation treatment, the pickling, the complexation dissolution, and the surface activation treatment are performed sequentially. And / or, the surface activation treatment includes: The medical zirconium-niobium alloy, after being dissolved by complexation, is subjected to a second impregnation treatment in an activation solution; And / or, the surface treatment method for the medical zirconium-niobium alloy further includes at least one of the following steps: A pretreatment step is included before the pre-oxidation treatment. The washing and drying steps are provided after the surface activation treatment; And / or, the medical zirconium-niobium alloy comprises a Zr-2.5Nb-0.1O alloy; And / or, the medical zirconium-niobium alloy may be in the form of at least one of rods or plates; And / or, the surface treatment method for the medical zirconium-niobium alloy is the surface treatment method for the medical zirconium-niobium alloy before high-temperature oxidation.

8. The surface treatment method according to claim 7, wherein The activation solution comprises 65-68 wt% nitric acid and ultrapure water, and the 65-68 wt% nitric acid in the activation solution has a mass content of 2-3%. And / or, the second impregnation treatment is a static impregnation treatment; And / or, the temperature of the second impregnation treatment is 25-30°C; And / or, the processing time for the second impregnation treatment is 2-3 minutes; And / or, the surface activation treatment further includes a first cleaning performed before the second immersion treatment and a second cleaning performed after the second immersion treatment; And / or, the preprocessing step includes: The medical zirconium-niobium alloy was mechanically polished, degreased, and washed with water. And / or, the washing and drying steps include: The surface-activated medical zirconium-niobium alloy is boiled, rinsed, and dried.

9. The surface treatment method according to claim 8, wherein The first cleaning process uses ultrapure water rinsing, and the second cleaning process uses ultrapure water rinsing. And / or, the mechanical polishing is performed using 320-1000 grit SiC sandpaper, and the surface roughness of the medical zirconium-niobium alloy after polishing is below 0.6 μm; And / or, the degreasing cleaning is performed using analytical grade anhydrous ethanol for ultrasonic cleaning, wherein the ultrasonic cleaning power is 200-300W and the ultrasonic cleaning time is 3-6min; And / or, in the washing and drying steps, the detergents used for boiling and rinsing include ultrapure water; And / or, in the washing and drying steps, the temperature of the boiling wash is 80-85℃, and the boiling wash time is 5-8 minutes; And / or, in the washing and drying steps, the drying method includes vacuum drying, the drying temperature is 60-70℃, and the drying time is 30-40 minutes.

10. The application of the surface treatment method as described in any one of claims 1 to 9 in the surface treatment process before high-temperature oxidation of medical zirconium-niobium alloys.

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