CN113529158B

CN113529158B - Process for preparing porous structure on surface of TC4 titanium alloy by electrochemical dealloying method

Info

Publication number: CN113529158B
Application number: CN202110858390.6A
Authority: CN
Inventors: 周文昊; 余森; 荆磊; 刘汉源; 白天
Original assignee: Northwest Institute for Non Ferrous Metal Research
Current assignee: Northwest Institute for Non Ferrous Metal Research
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2022-08-02
Anticipated expiration: 2041-07-28
Also published as: CN113529158A

Abstract

The invention discloses a process for preparing a porous structure on the surface of a TC4 titanium alloy by an electrochemical dealloying method, which comprises the following steps: adding a concentrated nitric acid solution and hydrogen peroxide into deionized water to prepare a mixed solution; polishing the TC4 titanium alloy, cleaning and drying; and thirdly, performing electrochemical dealloying treatment on the dried TC4 titanium alloy by using the mixed solution as electrolyte to obtain the TC4 titanium alloy with the porous structure on the surface. According to the invention, the relatively active Al and V in the surface layer of the TC4 titanium alloy are effectively removed by adopting an electrochemical dealloying method, an integrated porous structure is formed on the surface of the TC4 titanium alloy, a bonding interface of the porous structure and the TC4 titanium alloy is avoided, the stability of the porous structure is improved, and the dissolution of harmful elements Al and V in the subsequent use process is avoided, so that the organism implantation safety of the TC4 titanium alloy with the porous structure on the surface of the final product is greatly improved.

Description

Process for preparing porous structure on surface of TC4 titanium alloy by electrochemical dealloying method

Technical Field

The invention belongs to the technical field of biomedical materials, and particularly relates to a process for preparing a porous structure on the surface of a TC4 titanium alloy by an electrochemical dealloying method.

Background

With the increasing of human joint and bone tissue damage cases caused by aging of Chinese population, frequent natural disasters, traffic accidents, sports injuries and the like, the demand of people for biomedical materials is increasing day by day. The biomedical metal titanium alloy material mainly made of TC4 titanium alloy is a main biomedical material with large clinical dosage due to the excellent performances of high toughness, fatigue resistance, easy processing and forming, high reliability and the like. Although the TC4 titanium alloy has excellent biocompatibility and comprehensive mechanical properties, the titanium alloy still belongs to a biological inert material, has no biological activity and osteoinductivity, and is difficult to form biological combination with hard tissues after being implanted into a human body. Therefore, it is necessary to modify the surface of the TC4 titanium alloy, so as to not only retain the excellent comprehensive mechanical properties and lower elastic modulus of the TC4 titanium alloy, but also improve the surface properties and improve the biocompatibility of the titanium alloy, so that the titanium alloy can be better applied to clinics and serves the human body.

The conventional TC4 titanium alloy surface modification method comprises physical surface modification such as plasma spraying, ion implantation and the like, and the method forms simple mechanical bonding between a coating and a substrate on the surface of the titanium alloy, and the coating is thin and has poor bonding force. The chemical and electrochemical surface modification method is to activate the surface of the titanium alloy through chemical reaction on the interface of the metal and the solution, such as sol-gel, micro-arc oxidation and the like, which are the most commonly used methods for biological activation of the surface of the titanium alloy at present, and various microstructures including nano structures (nano rods, nano flower clusters, nano fibers and the like) and micro-nano composite structures (micro-nano pits, micro-nano holes and the like) can be generated on the surface by finely controlling reaction conditions and reasonably using the modification method, so that the osteoproliferation binding capacity of the surface can be regulated without using bioactive factors, and the method is also called as surface microstructuring.

A large number of researches and clinical experiments show that although traditional surface micro-structural technologies such as micro-arc oxidation, anodic oxidation and the like can obviously improve the biological properties of titanium and titanium alloy and accelerate osseointegration, the traditional surface micro-structural technologies all belong to 'additive' coatings, the risk of coating falling off exists after the traditional surface micro-structural technologies are implanted into a human body, an interface is added between an implant and tissues, and the healing process is complicated, so that the non-coating surface modification technology becomes an important direction for surface modification. Dealloying is a "subtractive", non-coated surface modification technique that does not risk flaking of the coating, and also improves the biocompatibility of the matrix material, and the new tissue is directly bonded to the implant matrix. Harmful metal ions on the surface are removed through a dealloying technology, a microstructured pattern is obtained on the metal surface, the functionality of the material surface is improved, and the metal implant material with the multi-level porosity and the compact bone simulation metal implant shows better biocompatibility.

The defects of the existing TC4 titanium alloy surface adopting a structuring technology (micro-arc oxidation and anodic oxidation) are as follows: the coating is a porous structure obtained by upward growth of a substrate and is an additive coating, and an obvious interface exists between the coating and the substrate, so that the coating is not firmly combined; secondly, the surface contains harmful elements Al and V, and the harmful elements Al and V are slowly dissolved out after being implanted into a human body, so that the human body can be damaged; insufficient surface osteogenic activity leads to poor in vivo osteointegration after implantation, ultimately leading to implant failure.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a process for preparing a porous structure on the surface of a TC4 titanium alloy by an electrochemical dealloying method, aiming at the defects of the prior art. According to the process, the relatively active Al and V in the surface layer of the TC4 titanium alloy are effectively removed by adopting an electrochemical dealloying method, an integrated porous structure is formed on the surface of the TC4 titanium alloy, a bonding interface of the porous structure and the TC4 titanium alloy is avoided, the stability of the porous structure is improved, and the dissolution of harmful elements Al and V in the subsequent use process is avoided, so that the organism implantation safety of the TC4 titanium alloy with the porous structure on the surface of the final product is greatly improved.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a process for preparing a porous structure on the surface of a TC4 titanium alloy by an electrochemical dealloying method is characterized by comprising the following steps:

step one, adding a concentrated nitric acid solution and hydrogen peroxide into deionized water to prepare a mixed solution;

step two, sequentially polishing TC4 titanium alloy by using 800#, 1000#, 1500# and 2000# abrasive paper until the surface has no visible obvious scratch, and then sequentially ultrasonically cleaning by using acetone, ethanol and deionized water and drying;

and step three, placing the mixed solution obtained in the step one in an electrochemical device as electrolyte, carrying out electrochemical dealloying treatment on the dried TC4 titanium alloy in the step two under the condition of room temperature and constant pressure, forming micron-sized pores on the surface of the TC4 titanium alloy, and carrying out cleaning and drying post-treatment to obtain the TC4 titanium alloy with the porous structure on the surface.

The invention adopts an electrochemical dealloying process, utilizes a mixed solution containing concentrated nitric acid and hydrogen peroxide as an electrolyte to carry out electrolytic corrosion on the surface of TC4 titanium alloy (nominal component Ti-6Al-4V), effectively removes relatively active Al and V in the surface layer of the TC4 titanium alloy, and simultaneously carries out oxidation, thereby forming a component of TiO ₂ The porous structure is prepared on the surface of the TC4 titanium alloy; because a porous structure is prepared by adopting a subtraction method and is formed along the inward direction of the surface of the TC4 titanium alloy, the porous structure and the TC4 titanium alloy are in an integral structure, a bonding interface does not exist between the porous structure and the TC4 titanium alloy, the stability of the porous structure is improved, and the falling of the porous structure is avoided, so that the organism implantation safety of the TC4 titanium alloy with the porous structure on the surface of a final product is greatly improved, and meanwhile, harmful elements Al and V are removed by electrolytic corrosion, namely the harmful elements Al and V do not exist in the porous structure, the harmful elements Al and V released after the TC4 titanium alloy with the porous structure on the surface is implanted into a human body are prevented from influencing the cell growth around the implanted body and even killing the cells, the infection probability is increased, implantation failure is caused, and the biological safety of the TC4 titanium alloy with the porous structure on the surface is further improved.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that in the step one, the mass concentration of the concentrated nitric acid solution is 68%, the mass concentration of hydrogen peroxide is 30%, the volume content of the concentrated nitric acid solution in the mixed solution is 0.5% -2%, and the volume content of the hydrogen peroxide is 0.5% -1%. The mixed solution with the optimal composition not only effectively removes Al and V in the surface layer of the TC4 titanium alloy, improves the biological safety of a target product, but also is beneficial to adjusting the rate and the degree of electrolytic corrosion, and a uniform three-dimensional reticular pore porous structure is prepared on the surface of the TC4 titanium alloy.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that the preparation process of the mixed solution in the step one is as follows: firstly, adding a concentrated nitric acid solution into deionized water, uniformly mixing, and then adding hydrogen peroxide, and uniformly mixing.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that acetone and ethanol in the second step and ethanol in the third step are analytical reagents. The preferred reagent grade removes impurities from the surface of the polished TC4 titanium alloy while avoiding the introduction of new impurities.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that the drying temperature in the second step and the drying time in the third step are both 60 ℃ and 30 min. The optimized drying process parameters not only improve the drying speed, but also avoid the influence of overhigh temperature on the surface composition and the appearance of the TC4 titanium alloy.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that the corrosion voltage adopted by the electrochemical dealloying treatment in the step III is 1.0-6.0V, and the corrosion time is 30-60 min; the aperture of the micron-sized porous is 200-500 μm. The optimized technological parameters effectively remove Al and V in the TC4 titanium alloy surface layer, ensure the formation of micron-sized pores, and control the pore size of the micron-sized pores, so that the porous structure is uniformly distributed in a three-dimensional net shape, and the adhesion growth of cells in the porous structure is facilitated.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that the post-treatment in the step three comprises the following specific steps: and (3) turning off a power supply of the electrochemical device, taking out the TC4 titanium alloy subjected to electrochemical dealloying treatment by using tweezers, then sequentially ultrasonically cleaning for 15min by using ethanol and deionized water, and then placing in a constant-temperature air-blast drying oven for drying. The preferable post-treatment process enables the pollutant layers in the micron-sized pores formed on the surface of the TC4 titanium alloy and the surface of the TC4 titanium alloy to be quickly peeled off to achieve the purpose of cleaning, and the cleaning effect is good and the time is saved.

The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method is characterized in that the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface in the third step is 1-3 mu m. The porous structure with the optimal thickness increases the wettability of the structure without damaging the mechanical property of the substrate, namely TC4 titanium alloy, and is beneficial to cell adhesion and growth.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, an electrochemical dealloying process is adopted, so that micron-scale porosity is generated on the surface of the TC4 titanium alloy, an integrated porous structure is formed on the surface of the TC4 titanium alloy, a bonding interface of the porous structure and the TC4 titanium alloy is avoided, the stability of the porous structure is improved, the falling of the porous structure is avoided, and the organism implantation safety of the TC4 titanium alloy with the porous structure on the surface of a final product is greatly improved.

2. The invention adopts the mixed solution containing concentrated nitric acid and hydrogen peroxide as the electrolyte to carry out the electrochemical dealloying process, thereby not only ensuring the formation of micron-scale pores on the surface of the TC4 titanium alloy, but also effectively removing harmful elements Al and V, avoiding the dissolution of Al and V in the subsequent use process, and greatly improving the biological safety of the TC4 titanium alloy.

3. The micron-sized porous structure formed on the surface of the TC4 titanium alloy has the potential of inducing osteogenic differentiation of cells, so the micron-sized porous structure has good capacity of inducing bone regeneration, improves the osseointegration performance with bone tissues around organisms after being implanted as an orthopedic transplanting device (prosthesis), prolongs the service period of the bone tissue, and is suitable for treating bone defects, particularly for treating patients with pathologically induced bone resorption and fracture.

Drawings

FIG. 1 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 1 of the invention.

FIG. 2 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 2 of the invention.

FIG. 3 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 3 of the invention.

FIG. 4 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 4 of the invention.

FIG. 5 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 5 of the invention.

FIG. 6 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 6 of the invention.

FIG. 7 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 7 of the present invention.

FIG. 8 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 8 of the present invention.

FIG. 9 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 9 of the invention.

FIG. 10 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 10 of the present invention.

FIG. 11 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 11 of the present invention.

FIG. 12 is a micro-topography of TC4 titanium alloy with a porous structure on the surface obtained in example 12 of the present invention.

Fig. 13 is a graph showing the proliferation activity performance of the TC4 titanium alloy and the TC4 titanium alloy with the porous structure on the surface prepared in example 3, example 6 and example 9 as implant materials.

Detailed Description

Example 1

Step one, adding 10mL of concentrated nitric acid solution with the mass concentration of 68% into 400mL of deionized water, uniformly stirring, adding 5mL of hydrogen peroxide with the mass concentration of 30%, uniformly stirring, adding 85mL of deionized water, and preparing to obtain a mixed solution;

polishing TC4 titanium alloy with the specification of 10mm multiplied by 1mm (length multiplied by width multiplied by thickness) by sequentially adopting 800#, 1000#, 1500# and 2000# abrasive paper until the surface has no obvious scratches visible to naked eyes, then respectively ultrasonically cleaning for 15min by sequentially adopting acetone, ethanol and deionized water, placing in an oven, drying for 30min at 60 ℃, and carrying out vacuum packaging for later use; the acetone and the ethanol are analytical pure reagents;

step three, placing the mixed solution obtained in the step one in an electrochemical device as electrolyte, placing the dried TC4 titanium alloy in the step two in the electrolyte as an anode, taking a platinum electrode as a cathode, performing electrochemical dealloying treatment on the anode for 30min under the constant-temperature and constant-voltage condition by adopting corrosion voltage of 1.0V, forming micron-sized pores with the pore diameter of 500 mu m on the surface of the TC4 titanium alloy, closing a power supply of the electrochemical device, taking out the TC4 titanium alloy subjected to the electrochemical dealloying treatment by adopting tweezers, sequentially performing ultrasonic cleaning for 15min by adopting analytically pure ethanol and deionized water respectively, and then placing in a constant-temperature blast drying oven to dry for 30min at 60 ℃ to obtain the TC4 titanium alloy with the porous structure on the surface; the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 1 μm.

Comparative example 1

This comparative example differs from example 1 in that: in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 0.5V, and the time is 30 min.

The TC4 titanium alloy of the comparative example was found to have almost no change in surface and no porous structure was formed.

Comparative example 2

This comparative example differs from example 1 in that: in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 0.5V, and the time is 60 min.

Comparative example 3

This comparative example differs from example 1 in that: in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 10V, and the time is 30 min.

It was detected that the porous structure formed on the surface of the TC4 titanium alloy of the present comparative example collapsed.

Comparing example 1 with comparative examples 1 to 3, it is understood that when the corrosion voltage used for the electrochemical dealloying treatment is too small, a porous structure cannot be formed on the surface of the TC4 titanium alloy even if the treatment time is prolonged (from 30min in comparative example 1 to 60min in comparative example 2), and when the corrosion voltage used for the electrochemical dealloying treatment is too large, excessive electrolytic corrosion occurs, and the porous structure collapses and breaks, so that an ideal porous structure cannot be obtained.

Comparative example 4

This comparative example differs from example 1 in that: the time for the electrochemical dealloying treatment in the third step is 25 min.

Comparative example 5

This comparative example differs from example 1 in that: the time for the electrochemical dealloying treatment in the third step is 65 min.

Comparing example 1 with comparative examples 4 to 5, it is understood that when the time for the electrochemical dealloying treatment is too short, a porous structure cannot be formed on the surface of the TC4 titanium alloy, and when the time for the electrochemical dealloying treatment is too long, excessive electrolytic corrosion occurs, causing collapse damage to the porous structure, and an ideal porous structure cannot be obtained.

Example 2

The present embodiment is different from embodiment 1 in that: in the first step, 5mL of concentrated nitric acid solution with the mass concentration of 68% is added into 492mL of deionized water to be uniformly stirred, and then 3mL of hydrogen peroxide with the mass concentration of 30% is added to be uniformly stirred; in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 1.0V, the time is 45min, micron-sized pores with the pore diameter of 300 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 3

The present embodiment is different from embodiment 1 in that: in the first step, 10mL of concentrated nitric acid solution with the mass concentration of 68% is added into 487.5mL of deionized water and stirred uniformly, and then 2.5mL of hydrogen peroxide with the mass concentration of 30% is added and stirred uniformly; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 1.0V, the time is 60min, micron-sized pores with the pore diameter of 400 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 4

The present embodiment is different from embodiment 1 in that: adding 3mL of concentrated nitric acid solution with the mass concentration of 68% into 492mL of deionized water, uniformly stirring, adding 5mL of hydrogen peroxide with the mass concentration of 30%, uniformly stirring; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 2.0V, the time is 30min, micron-sized pores with the pore diameter of 200 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 5

The present embodiment is different from embodiment 1 in that: in the first step, 5mL of concentrated nitric acid solution with the mass concentration of 68% is added into 492.5mL of deionized water to be uniformly stirred, and then 2.5mL of hydrogen peroxide with the mass concentration of 30% is added to be uniformly stirred; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 2.0V, the time is 45min, micron-sized pores with the pore diameter of 300 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 6

The present embodiment is different from embodiment 1 in that: in the first step, 2.5mL of concentrated nitric acid solution with the mass concentration of 68% is added into 493.5mL of deionized water and stirred uniformly, and then 4mL of hydrogen peroxide with the mass concentration of 30% is added and stirred uniformly; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 2.0V, the time is 60min, micron-sized pores with the pore diameter of 350 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 7

The present embodiment is different from embodiment 1 in that: in the first step, 4mL of concentrated nitric acid solution with the mass concentration of 68% is added into 492mL of deionized water to be uniformly stirred, and then 4mL of hydrogen peroxide with the mass concentration of 30% is added to be uniformly stirred; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 3.0V, the time is 30min, micron-sized pores with the pore diameter of 200 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 8

The present embodiment is different from embodiment 1 in that: the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 3.0V, the time is 45min, micron-sized pores with the pore diameter of 300 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 3 mu m.

Example 9

The present embodiment is different from embodiment 1 in that: in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 3.0V, the time is 60min, micron-sized pores with the pore diameter of 300 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 10

The present embodiment is different from embodiment 1 in that: adding 7mL of concentrated nitric acid solution with the mass concentration of 68% into 489mL of deionized water, uniformly stirring, adding 4mL of hydrogen peroxide with the mass concentration of 30%, uniformly stirring; the corrosion voltage adopted by the electrochemical dealloying treatment in the third step is 6.0V, the time is 30min, micron-sized pores with the pore diameter of 400 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 3 mu m.

Example 11

The present embodiment is different from embodiment 1 in that: adding 8mL of concentrated nitric acid solution with the mass concentration of 68% into 488mL of deionized water, uniformly stirring, adding 4mL of hydrogen peroxide with the mass concentration of 30%, uniformly stirring; in the third step, the corrosion voltage adopted by the electrochemical dealloying treatment is 6.0V, the time is 45min, micron-sized pores with the pore diameter of 500 mu m are formed on the surface of the TC4 titanium alloy, and the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 2 mu m.

Example 12

The embodiment comprises the following steps:

step three, placing the mixed solution obtained in the step one in an electrochemical device as electrolyte, placing the dried TC4 titanium alloy in the step two in the electrolyte as an anode, taking a platinum electrode as a cathode, performing electrochemical dealloying treatment on the anode for 60min under the constant-temperature and constant-voltage condition by adopting 6.0V corrosion voltage, forming micron-sized pores with the pore diameter of 500 mu m on the surface of the TC4 titanium alloy, closing a power supply of the electrochemical device, taking out the TC4 titanium alloy subjected to the electrochemical dealloying treatment by adopting tweezers, sequentially performing ultrasonic cleaning for 15min by adopting analytically pure ethanol and deionized water respectively, and then placing in a constant-temperature blast drying oven to dry for 30min at 60 ℃ to obtain the TC4 titanium alloy with the porous structure on the surface; the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface is 3 mu m.

Fig. 1 to 12 are microscopic morphology diagrams of TC4 titanium alloy with a porous structure on the surface obtained in examples 1 to 12 of the present invention, and as can be seen from fig. 1 to 12, the TC4 titanium alloy with a porous structure on the surface prepared by an electrochemical dealloying method of the present invention has a regular morphology and uniform pore distribution.

The proliferation activity performance of the TC4 titanium alloy and the TC4 titanium alloy with the porous structure on the surface, which is prepared in the embodiments 3, 6 and 9, as the implant material is measured by adopting a CCK-8 method, and the specific operation flow is as follows: placing the well plate in a clean bench, placing the implant material in the well plate, adding the culture medium and the mouse osteogenic precursor cell suspension, placing in an incubator at 37 deg.C for the same time, and culturingTaking out, placing in a clean bench, removing culture medium with pipette, adding culture solution containing 10% CCK-8, and placing in CO ₂ The cells were cultured in an incubator at 37 ℃ for 1d, 3d and 5d, respectively, and the cell proliferation activities of the TC4 titanium alloy and the TC4 titanium alloy having a porous structure on the surface were measured, and the results are shown in FIG. 13. As can be seen from fig. 13, the cell proliferation activities of the TC4 titanium alloys with porous structures on the surfaces prepared in examples 3, 6 and 9 are all higher than that of the TC4 titanium alloy, and the longer the culture time is, the higher the cell proliferation activity is, which indicates that the TC4 titanium alloy with porous structures on the surfaces prepared by the electrochemical dealloying method of the present invention effectively promotes cell proliferation and has a long-term stable promoting effect.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, change and equivalent changes of the above embodiments according to the technical essence of the invention are still within the protection scope of the technical solution of the invention.

Claims

1. A process for preparing a porous structure on the surface of a TC4 titanium alloy by an electrochemical dealloying method is characterized by comprising the following steps:

step one, adding a concentrated nitric acid solution and hydrogen peroxide into deionized water to prepare a mixed solution; the mass concentration of the concentrated nitric acid solution is 68%, the mass concentration of the hydrogen peroxide is 30%, the volume content of the concentrated nitric acid solution in the mixed solution is 0.5-2%, and the volume content of the hydrogen peroxide is 0.5-1%;

step three, placing the mixed solution obtained in the step one in an electrochemical device as electrolyte, performing electrochemical dealloying treatment on the dried TC4 titanium alloy in the step two under the condition of room temperature and constant pressure, forming micron-sized pores on the surface of the TC4 titanium alloy, and performing cleaning and drying post-treatment to obtain the TC4 titanium alloy with the porous structure on the surface; the corrosion voltage adopted by the electrochemical dealloying treatment is 1.0V-6.0V, and the corrosion time is 30 min-60 min; the aperture of the micron-sized porous is 200-500 mu m.

2. The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method according to claim 1, wherein the preparation process of the mixed solution in the step one is as follows: firstly, adding a concentrated nitric acid solution into deionized water, uniformly mixing, and then adding hydrogen peroxide, and uniformly mixing.

3. The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method as claimed in claim 1, wherein the acetone and the ethanol in the second step and the ethanol in the third step are analytical reagents.

4. The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method according to claim 1, wherein the drying temperature in the second step and the drying time in the third step are both 60 ℃ and 30 min.

5. The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method according to claim 1, wherein the post-treatment in the third step comprises the following specific steps: and (3) turning off a power supply of the electrochemical device, taking out the TC4 titanium alloy subjected to electrochemical dealloying treatment by using tweezers, then sequentially ultrasonically cleaning for 15min by using ethanol and deionized water, and then placing in a constant-temperature air-blast drying oven for drying.

6. The process for preparing the porous structure on the surface of the TC4 titanium alloy by the electrochemical dealloying method as claimed in claim 1, wherein the thickness of the porous structure in the TC4 titanium alloy with the porous structure on the surface in the third step is 1 μm-3 μm.