Ti6al4v surface diamond-doped micro-arc oxidation wear-resistant bioactive coating and preparation method thereof

Abstract

The application is a kind of Ti6Al4V surface diamond doped micro-arc oxidation wear-resistant bioactive coating, which is composed of a ceramic layer mainly of TiO2 and randomly distributed nano-diamond particles formed after micro-arc oxidation on the surface of Ti6Al4V base material, and the Al and V contents in the coating are less than 1.0wt% and 0.1wt% respectively. The preparation method comprises the following steps: configuring sodium silicate, sodium phosphate or beta-glycerophosphorus sodium, sodium hydroxide into electrolyte, adding nano-diamond powder and anti-settling agent to make nano-diamond uniformly dispersed in the electrolyte, and then using micro-arc oxidation technology to prepare low Al and low V diamond doped micro-arc oxidation bioactive coating in the electrolyte. The application scheme is simple and easy to operate, the wear resistance of the coating can be improved by 2-5 times, in addition, the harmful elements Al and V in the coating are low, which is suitable for being used as biomedical implant materials.

Description

Technical Field

[0001] This invention relates to the field of bio-modified coating technology, specifically a diamond-doped micro-arc oxidation wear-resistant bioactive coating on Ti6Al4V surface and its preparation method. Background Technology

[0002] With the increasing incidence of bone injuries and defects and the improvement of living standards, the medical community has higher and higher demands for bio-implant materials for hard tissue replacement, bone fixation, and repair. Ti6Al4V alloy has become one of the most commonly used biomedical bone implant materials due to its excellent mechanical properties and corrosion resistance. Its excellent mechanical properties are achieved through the addition of Al and V elements, but these two elements have toxic side effects. For example, direct ingestion of aluminum can cause neurological disorders and induce poisoning diseases such as osteomalacia and renal insufficiency, while V directly affects osteoblast metabolism. Its excellent corrosion resistance comes from its thin, naturally formed TiO2 surface layer, but it is prone to fracture once subjected to wear.

[0003] In recent years, scholars have studied the use of β-titanium alloys to replace Ti6Al4V, improving the safety of titanium alloy implants by replacing aluminum and V with safer elements such as Nb, Ta, Zr, and Mo. However, the smelting process of these alternative alloys is more complex and expensive; therefore, Ti6Al4V alloys will remain irreplaceable in clinical applications for a considerable period. Besides the risks of toxicity, titanium alloy implants also suffer from insufficient osseointegration and poor wear resistance.

[0004] Surface modification is an effective method to address the Al and V precipitation problem in Ti6Al4V alloys. Furthermore, by selecting appropriate components or constructing micro / nano composite biomimetic structures, the biocompatibility, osseointegration capacity, and wear resistance of Ti6Al4V alloys can be improved. Micro-arc oxidation technology can construct microporous and nanoporous modified oxide ceramic coatings on titanium alloy surfaces, achieving dual modification of composition and morphology. This has been proven to improve protein and cell adhesion, promote mechanical interlocking between implants and bone tissue, ultimately accelerating osseointegration and reducing the risk of aseptic loosening. In recent years, electrolyte selection and optimization, and the addition of micron or nanoparticles have become hot topics in the micro-arc oxidation modification of titanium alloy surfaces, used to reduce surface Al and V content, modify the morphology of surface oxide ceramic layers, and improve the wear resistance of micro-arc oxidation layers.

[0005] Diamond, as an inorganic material with high hardness, good wear resistance, and strong corrosion resistance, has been widely used in various fields. Furthermore, its chemical inertness, biocompatibility, and non-toxicity make it an implantable material. However, there are currently no reports on using diamond as an additive in electrolytes for the preparation of micro-arc oxidation coatings. Summary of the Invention

[0006] The purpose of this invention is to address the problems of precipitation risk, insufficient osseointegration capacity, and insufficient wear resistance of Ti6Al4V alloy as an implant, and to propose a low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V.

[0007] This invention is achieved through the following technical solution:

[0008] A diamond-doped micro-arc oxidation wear-resistant bioactive coating on Ti6Al4V surface is provided. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, and the Al content in the coating is less than 1.0 wt% and the V content is less than 0.1 wt%.

[0009] Preferably, the particle size of the nanodiamond particles is 15,000 to 60,000 mesh, and the thickness of the ceramic layer is 1 to 50 μm.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V, comprising the following steps:

[0011] A: Preliminary processing: The surface of the Ti6Al4V matrix material to be reinforced is sanded and polished to remove surface oil and oxide scale;

[0012] B: Micro-arc oxidation electrolyte preparation: Sodium silicate, sodium phosphate, and sodium hydroxide are used to prepare the electrolyte, or sodium silicate, β-glycerophosphate, and sodium hydroxide are used to prepare the electrolyte. Then, nano-diamond particles and anti-precipitant are added to the electrolyte. The electrolyte is continuously stirred for 10-30 minutes using a non-magnetic rotor, and then the electrolyte is vibrated with ultrasound for 20-60 minutes to ensure that the nano-diamond particles are evenly distributed in the electrolyte.

[0013] C: Micro-arc oxidation: The Ti6Al4V substrate material treated in step A is encapsulated with AB glue and placed in a micro-arc oxidation device. Voltage and current are applied to allow the electrolyte to react with the Ti6Al4V substrate material in a micro-arc oxidation reaction. After the micro-arc oxidation reaction is completed, the Ti6Al4V substrate material is cleaned with ultrasound to obtain the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface.

[0014] Preferably, in step B, when preparing the electrolyte, the concentration of sodium silicate is 3~20 g / L, the concentration of sodium phosphate is 1~25 g / L, the concentration of β-glycerophosphate sodium is 1~12 g / L, the concentration of sodium hydroxide is 2~24 g / L, and the content of nanodiamond particles in the electrolyte is 1~5 g / L.

[0015] Preferably, in step B, the anti-precipitant is sodium pyrophosphate or polyethylene glycol.

[0016] Preferably, when sodium pyrophosphate is used as the anti-precipitant, its content in the electrolyte is 0.5-1.5 g / L; when polyethylene glycol is used as the anti-precipitant, its molecular weight is 400-1000, and its content in the electrolyte is 0.5-3 g / L.

[0017] Preferably, in step C, if a constant voltage mode is used for the micro-arc oxidation reaction, the voltage is 350-550V and the time is 5-60 min.

[0018] Preferably, in step C, during the micro-arc oxidation reaction, if a constant current mode is used, the current is 0.2~0.5A and the time is 5~60 min.

[0019] Preferably, in step C, during the micro-arc oxidation reaction, a stirring device is used to continuously stir the electrolyte to prevent the nanodiamond particles from settling.

[0020] This invention combines the advantages of nanodiamond and micro-arc oxidation technology to propose a low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating and its preparation method, which solves the problems of precipitation risk, insufficient osseointegration capacity and wear resistance of Ti6Al4V alloy as an implant.

[0021] This invention utilizes an electrolyte composed of sodium silicate, sodium phosphate / β-glycerophosphate, and sodium hydroxide to reduce the content of Al and V elements in the micro-arc oxidation layer through chemical reactions during the micro-arc oxidation process. In particular, the content of V element can be reduced to below 0.1%. The residual Al element is relatively high, but the residual Al exists in the form of oxides, which can fix Al and reduce the risk of its precipitation. Incorporating nanodiamond particles into the electrolyte allows them to penetrate the coating under the influence of plasma. The high hardness, wear resistance, and corrosion resistance of diamond enhance the coating's resistance to wear and corrosion. Considering that nanodiamond particles tend to settle and agglomerate in the electrolyte, and that smaller particle sizes are more prone to agglomeration and more difficult to disperse, the particle size of the nanodiamond particles is initially set at the submicron level, approximately 0.2-0.85 micrometers. Then, a combination of mechanical dispersion, ultrasonic dispersion, and chemical dispersion is used to suspend the nanodiamond particles in the electrolyte while preventing sedimentation. The process involves adding sodium pyrophosphate or polyethylene glycol simultaneously with the diamond powder. Adding sodium pyrophosphate adsorbs negative ions onto the surface of the nanodiamonds, improving their dispersibility in the electrolyte. Adding polyethylene glycol covers the surface of the nanodiamonds with polyethylene glycol molecules, achieving dispersion through steric hindrance. Subsequently, a non-magnetic rotor was used to stir the nanodiamond particles that had initially settled at the bottom of the electrolyte, bringing them into the electrolyte while simultaneously allowing the added anti-precipitation agent to function. Then, the cavitation and thermal effects of ultrasound were used to promote electrolyte distribution and disperse the nanodiamond agglomerates in the electrolyte, ultimately achieving the configuration of a nanodiamond suspension electrolyte. The amount of nanodiamond powder added and the electrolyte settings were based on experiments and were set with the goal of not affecting the micro-arc oxidation process. During the micro-arc oxidation process, a stirring device was used to continuously stir the electrolyte to prevent nanodiamond sedimentation, thereby ensuring the nanodiamond content in the electrolyte during the micro-arc oxidation process.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) The low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V of this invention is composed of a bioactive ceramic coating with TiO2 as the main phase and dispersed nanodiamond particles therein. It combines the good mechanical properties of Ti6Al4V with the good wear resistance and corrosion resistance of diamond-doped micro-arc oxidation ceramic coating. The wear resistance can be improved by 2-5 times compared with the diamond-free micro-arc oxidation layer. The micro-arc oxidation morphology is also conducive to cell and protein adsorption and promotes bone integration. The Al and V contents in the coating are low, less than 1.0 wt% and 0.1 wt% respectively. This value is much lower than the contents in Ti6Al4V alloy (Al 5.5~6.8 wt%, V 3.5~4.5 wt%) and ordinary micro-arc oxidation layer. As an implant, the risk of precipitation is greatly reduced. It can be applied to the repair and replacement of bone tissue defects in areas of the human body with high stress. It has better implantation effect than Ti6Al4V alloy or micro-arc oxidation treated Ti6Al4V alloy.

[0024] 2) In view of the problems of low bonding strength between coating and substrate and difficulty in controlling coating uniformity and stability in traditional biomaterial surface treatment technologies such as plasma spraying and electrodeposition, the oxide ceramic layer produced by the micro-arc oxidation technology of the present invention is mainly obtained by in-situ growth. The coating and substrate are metallurgically bonded, with high bonding strength, which is beneficial to the long-term service of the implant.

[0025] 3) This invention comprehensively employs mechanical dispersion, ultrasonic dispersion, and chemical dispersion to suspend nanodiamond particles in the electrolyte. The suspension rate of nanodiamonds is better than that of mechanical dispersion or ultrasonic dispersion alone, and the nanodiamonds can be guaranteed not to settle during the entire micro-arc oxidation process.

[0026] 4) The method of this invention is scientific and reasonable, simple to operate, and suitable for mass production. Attached Figure Description

[0027] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0028] Figure 1 This is a schematic diagram of the micro-arc oxidation device in this invention.

[0029] Figure 2 This is a surface morphology diagram of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface of the present invention.

[0030] Figure 3 This is a cross-sectional morphology diagram of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface of the present invention.

[0031] Figure 4This is a morphology image of the wear marks on the surface of the Ti6Al4V matrix material in this invention.

[0032] Figure 5 This image shows the wear track morphology of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface of the present invention.

[0033] Figure 6 The wear loss of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface of this invention is shown. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the present invention will be further described clearly and completely below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Example 1

[0035] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 20,000 mesh and a thickness of 30 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0036] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0037] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and polished to a mirror finish with diamond polishing paste to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 7 minutes. After natural air drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polishing surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0038] B: Preparation of micro-arc oxidation electrolyte: Weigh 10g of sodium silicate, 10g of sodium phosphate and 2g of sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved to make the concentration of sodium silicate in the electrolyte 10g / L, the concentration of sodium phosphate 10g / L and the concentration of sodium hydroxide 2g / L. Then weigh 2g of 20000 mesh diamond powder and 1g of sodium pyrophosphate using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 15min using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 30min to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0039] C: Micro-arc oxidation treatment: Figure 1 This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell in the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 100mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation process is then set up. The distance between the cathode and anode of the equipment is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant current mode is adopted, with the current set to 0.3A, the pulse width to 60μs, the pulse frequency to 800Hz, and the duty cycle to 3%. After micro-arc oxidation for 10 minutes, the micro-arc oxidation equipment and the stirring device are turned off. The Ti6Al4V substrate material after micro-arc oxidation is taken out, and the Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V.

[0040] Figure 2 The image shows the surface morphology of the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface prepared in this embodiment. As can be seen from the image, the surface is composed of micron-level protrusions and nano-level micropores on the protrusion surfaces. This micro-nano layered structure is beneficial for the adhesion of cells and proteins.

[0041] Figure 3 The image shows a cross-sectional morphology of the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface prepared in this embodiment. As can be seen from the image, the small black dots in the white box area are nanodiamond particles.

[0042] Figure 4This is a morphology image of the wear marks on the surface of the Ti6Al4V matrix material in this embodiment. Figure 5 The image shows the wear track morphology of the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface prepared in this embodiment. The tribological test was conducted under a load of 5N and a frequency of 2Hz, with GCr15 microspheres as the wear pair. Figure 4 and Figure 5 It can be clearly seen that the wear mark width of the Ti6Al4V matrix material is significantly narrowed after micro-arc oxidation treatment, indicating that the prepared low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface has good wear resistance.

[0043] Figure 6 The wear loss of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface prepared in this embodiment is shown in the figure. (a) is the original Ti6Al4V substrate material and (b) is the Ti6Al4V substrate material coating sample. By comparison, it can be seen that the wear loss of the Ti6Al4V substrate material coating sample is only 39% of that of the original Ti6Al4V substrate material, that is, the wear resistance is improved by about 2.5 times. Example 2

[0044] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 15,000 mesh and a thickness of 1 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0045] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0046] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and then polished to a mirror finish with diamond to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 5 minutes. After natural drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polished surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0047] B: Preparation of micro-arc oxidation electrolyte: Weigh 15g sodium silicate, 25g sodium phosphate and 10g sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved, so that the concentration of sodium silicate in the electrolyte is 15g / L, the concentration of sodium phosphate is 25g / L and the concentration of sodium hydroxide is 10g / L. Then weigh 5g of 15000 mesh diamond powder and 1.5g of sodium pyrophosphate using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 10min using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 50min to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0048] C: Micro-arc oxidation treatment: Figure 1 This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell in the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 500mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation process is then set up. The distance between the cathode and anode of the equipment is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant current mode is adopted, with the current set to 0.2A, the pulse width to 50μs, the pulse frequency to 500Hz, and the duty cycle to 25%. After micro-arc oxidation for 5 minutes, the micro-arc oxidation equipment and the stirring device are turned off. The Ti6Al4V substrate material after micro-arc oxidation is taken out, and the Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V. Example 3

[0049] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 20,000 mesh and a thickness of 50 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0050] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0051] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and then polished to a mirror finish with diamond to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 8 minutes. After natural drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polished surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0052] B: Preparation of micro-arc oxidation electrolyte: Weigh 5g of sodium silicate, 1g of sodium phosphate, and 6g of sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved, so that the concentration of sodium silicate in the electrolyte is 5g / L, the concentration of sodium phosphate is 1g / L, and the concentration of sodium hydroxide is 6g / L. Then, weigh 3g of 20000-mesh diamond powder and 0.5g of sodium pyrophosphate using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 20 minutes using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 20 minutes to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0053] C: Micro-arc oxidation treatment: Figure 1 This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell of the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 250mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation device is then set up. The distance between the cathode and anode is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant current mode is adopted, with the current set to 0.5A, the pulse width to 70μs, the pulse frequency to 600Hz, and the duty cycle to 10%. After micro-arc oxidation for 60min, the micro-arc oxidation equipment and the stirring device are turned off, and the Ti6Al4V substrate material after micro-arc oxidation is taken out. The Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V. Example 4

[0054] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 40,000 mesh and a thickness of 3 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0055] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0056] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and then polished to a mirror finish with diamond to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 6 minutes. After natural drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polished surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0057] B: Preparation of micro-arc oxidation electrolyte: Weigh 3g of sodium silicate, 12g of sodium β-glycerophosphate and 15g of sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved to make the concentration of sodium silicate in the electrolyte 3g / L, the concentration of sodium β-glycerophosphate 12g / L and the concentration of sodium hydroxide 15g / L. Then weigh 1g of 40000 mesh diamond powder and 3g of polyethylene glycol using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 30min using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 60min to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0058] C: Micro-arc oxidation treatment: Figure 1This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell in the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 150mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation process is then set up. The distance between the cathode and anode of the equipment is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant voltage mode is adopted, with the voltage set to 350V, the pulse width to 40μs, the pulse frequency to 400Hz, and the duty cycle to 30%. After micro-arc oxidation for 5 minutes, the micro-arc oxidation equipment and the stirring device are turned off. The Ti6Al4V substrate material after micro-arc oxidation is taken out, and the Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V. Example 5

[0059] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 60,000 mesh and a thickness of 45 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0060] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0061] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and then polished to a mirror finish with diamond to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 10 minutes. After natural drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polished surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0062] B: Preparation of micro-arc oxidation electrolyte: Weigh 18g of sodium silicate, 1g of sodium β-glycerophosphate and 24g of sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved, so that the concentration of sodium silicate in the electrolyte is 18g / L, the concentration of sodium β-glycerophosphate is 1g / L and the concentration of sodium hydroxide is 24g / L. Then, weigh 4g of 60,000-mesh diamond powder and 0.5g of polyethylene glycol using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 25 minutes using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 40 minutes to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0063] C: Micro-arc oxidation treatment: Figure 1 This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell in the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 400mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation device is then set up. The distance between the cathode and anode is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant voltage mode is adopted, with the voltage set to 550V, the pulse width to 80μs, the pulse frequency to 700Hz, and the duty cycle to 25%. After micro-arc oxidation for 60min, the micro-arc oxidation equipment and the stirring device are turned off, and the Ti6Al4V substrate material after micro-arc oxidation is taken out. The Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V. Example 6

[0064] A diamond-doped micro-arc oxidation wear-resistant bioactive coating for Ti6Al4V surface is disclosed. The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, with a particle size of 50,000 mesh and a thickness of 33 μm. The coating contains less than 1.0 wt% Al and less than 0.1 wt% V.

[0065] The preparation method of the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface includes the following steps:

[0066] A: Preliminary processing of the substrate material: The surface of the Ti6Al4V substrate material is successively ground with #200 to #2000 sandpaper and then polished to a mirror finish with diamond to remove surface oil and oxide scale. Then, the Ti6Al4V substrate material is successively cleaned with alcohol and deionized water for 9 minutes. After natural drying, the dried Ti6Al4V substrate material is obtained. The Ti6Al4V substrate material is encapsulated with copper wire and AB glue, leaving the polished surface to be reacted, thus obtaining the preliminarily processed Ti6Al4V substrate material.

[0067] B: Preparation of micro-arc oxidation electrolyte: Weigh 20g sodium silicate, 8g sodium β-glycerophosphate and 20g sodium hydroxide using an electronic balance and add them to 1L of deionized water. Stir thoroughly until completely dissolved, so that the concentration of sodium silicate in the electrolyte is 20g / L, the concentration of sodium β-glycerophosphate is 8g / L and the concentration of sodium hydroxide is 20g / L. Then weigh 5g of 50,000-mesh diamond powder and 1.5g of polyethylene glycol using an electronic balance and add them to the electrolyte. Stir the electrolyte continuously for 25 minutes using a non-magnetic rotor, and then vibrate the electrolyte with ultrasound for 35 minutes to ensure that the nanodiamond particles are evenly distributed in the electrolyte to form a suspension.

[0068] C: Micro-arc oxidation treatment: Figure 1 This is a schematic diagram of a micro-arc oxidation device. The Ti6Al4V matrix material obtained in step A is clamped onto the anode copper plate of the electrolytic cell in the micro-arc oxidation device. The micro-arc oxidation electrolyte obtained in step B is poured into the stainless steel electrolytic cell in the micro-arc oxidation device. Then, the Ti6Al4V matrix material is placed into the electrolyte in the stainless steel electrolytic cell, 300mm below the liquid surface. During this process, a stirring device is used to continuously stir the electrolyte to ensure that the nanodiamond particles in the electrolyte do not settle. The cathode of the micro-arc oxidation power supply is connected to the stainless steel electrolytic cell, and the anode of the micro-arc oxidation power supply is connected to the anode copper plate clamped with the Ti6Al4V matrix material. The micro-arc oxidation device is then set up. The distance between the cathode and anode of the equipment is 200mm; the cooling circulating water is turned on to ensure that the temperature of the electrolyte in the stainless steel electrolytic cell is controlled below 40℃; the micro-arc oxidation equipment is started, and the constant voltage mode is adopted, with the voltage set to 450V, the pulse width to 50μs, the pulse frequency to 600Hz, and the duty cycle to 15%. After micro-arc oxidation for 30min, the micro-arc oxidation equipment and the stirring device are turned off, and the Ti6Al4V substrate material after micro-arc oxidation is taken out. The Ti6Al4V substrate material is ultrasonically treated with distilled water and anhydrous ethanol until the surface is clean, thus obtaining the low-Al, low-V diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V.

Claims

1. A diamond-doped micro-arc oxidation wear-resistant bioactive coating on the surface of Ti6Al4V, characterized in that: The coating consists of nanodiamond particles and a ceramic layer with TiO2 as the main phase formed by micro-arc oxidation. The nanodiamond particles are randomly dispersed in the ceramic layer, and the Al content in the coating is less than 1.0 wt%, with Al existing in the form of oxides, and the V content is less than 0.1 wt%. The particle size of the nanodiamond particles is 15,000 to 60,000 mesh, the thickness of the ceramic layer is 1 to 50 μm, and the coating surface has a micro-nano layered structure with micron-level protrusions and nano-level micropores on the protrusion surface.

2. The method for preparing a diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface according to claim 1, characterized in that, Includes the following steps: A: Preliminary processing: The surface of the Ti6Al4V matrix material to be reinforced is sanded and polished to remove surface oil and oxide scale; B: Micro-arc oxidation electrolyte preparation: The electrolyte is prepared using sodium silicate, sodium phosphate, and sodium hydroxide, or sodium silicate, β-glycerophosphate, and sodium hydroxide. The concentration of sodium silicate is 3~20 g / L, the concentration of sodium phosphate is 1~25 g / L, the concentration of β-glycerophosphate is 1~12 g / L, and the concentration of sodium hydroxide is 2~24 g / L. Then, nanodiamond particles and anti-precipitant are added to the electrolyte. The content of nanodiamond particles in the electrolyte is 1~5 g / L. The anti-precipitant is sodium pyrophosphate or polyethylene glycol. The electrolyte is continuously stirred for 10-30 min using a non-magnetic rotor, and then the electrolyte is oscillated with ultrasound for 20-60 min to ensure that the nanodiamond particles are uniformly distributed in the electrolyte. C： Micro-arc oxidation: The Ti6Al4V substrate material treated in step A is encapsulated with AB glue and placed in a micro-arc oxidation device. Voltage and current are applied to allow the electrolyte to react with the Ti6Al4V substrate material in a micro-arc oxidation reaction. During the micro-arc oxidation reaction, a stirring device is used to continuously stir the electrolyte to prevent the nanodiamond particles from settling. After the micro-arc oxidation reaction is completed, the Ti6Al4V substrate material is cleaned with ultrasound to obtain the diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface.

3. The method for preparing a diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface according to claim 2, characterized in that: When sodium pyrophosphate is used as the anti-precipitant, its content in the electrolyte is 0.5-1.5 g / L; when polyethylene glycol is used as the anti-precipitant, its molecular weight is 400-1000, and its content in the electrolyte is 0.5-3 g / L.

4. The method for preparing a diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface according to claim 2, characterized in that: In step C, the micro-arc oxidation reaction is carried out in constant voltage mode, with a voltage of 350-550V and a time of 5-60min.

5. The method for preparing a diamond-doped micro-arc oxidation wear-resistant bioactive coating on the Ti6Al4V surface according to claim 2, characterized in that: In step C, the micro-arc oxidation reaction is carried out in constant current mode, with a current of 0.2~0.5A and a time of 5~60min.

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