WO2021093690A1

WO2021093690A1 - Method for depositing hydroxyapatite on metal surface, and metal implant

Info

Publication number: WO2021093690A1
Application number: PCT/CN2020/127287
Authority: WO
Inventors: 姚夏睿; 俞天白
Original assignee: 苏州微创关节医疗科技有限公司
Priority date: 2019-11-11
Filing date: 2020-11-06
Publication date: 2021-05-20
Also published as: CN110724991A

Abstract

A method for depositing hydroxyapatite on a metal surface, and a metal implant. The method for depositing hydroxyapatite on a metal surface comprises: providing a metal substrate; forming a rough structure on the surface of the metal substrate; providing an electrolyte solution; and placing, in the electrolyte solution, the metal substrate having the rough structure formed on the surface thereof, and forming a hydroxyapatite layer on the rough structure by means of electrochemical deposition; raw materials for formulating the electrolyte solution comprise calcium salt, phosphate and hydrogen peroxide. An HA coating with high purity and crystallinity is formed on the surface of a metal implant obtained by the described method, and the HA coating has a relatively strong binding force to the surface of the metal implant, thereby improving the usage safety and reliability of the metal implant.

Description

Method for depositing hydroxyapatite on metal surface and metal implant

Technical field

The invention relates to the technical field of medical devices, in particular to a method for depositing hydroxyapatite on a metal surface and a metal implant.

Background technique

Metal materials have a wide range of applications in the field of medical implants due to their excellent properties. Common metal materials such as stainless steel, titanium and titanium alloys, zirconium and zirconium alloys, cobalt-chromium alloys, etc., have become orthopedics and dentistry due to their good biocompatibility, low toxicity, suitable mechanical strength and sufficient corrosion resistance. The first choice for hard tissue implantation and replacement. However, most metal materials tend to be biologically inert in the human body without special surface treatment. This makes it difficult for the metal implant to form an effective osseointegration interface with the surrounding bone tissue in the human body, which in turn leads to problems such as loosening of the metal implant, fibrosis of the surrounding tissue, and chronic inflammation.

Hydroxyapatite (HA, the molecular formula is Ca10(PO4)6(OH)2) is one of the main mineral components in animals and humans. The content of HA in human enamel reaches 96%wt, and the content of HA in bone The content reaches 69%wt. In the human body, HA is in the form of needle-like nanoparticles with a length of 20-40nm and a width of 2-4nm. A large number of studies have shown that the formation of HA particles on the surface of metal implants can improve the biocompatibility and biological activity of metal implants. Using HA particles as an inducing factor in the osteogenesis process is beneficial to the bone of metal implants. Integration process.

At present, a variety of metal implants with HA coatings formed on the surface have appeared on the market. These metal implants have HA coatings formed on metal substrates by means of plasma spraying, electrochemical deposition, and the like. However, the HA coating formed by the existing method still has some problems, resulting in poor performance of the metal implant. For example, the thickness of the HA coating formed by the plasma spraying method can reach tens or even hundreds of microns. In this method, HA powder is sprayed onto the metal implant by a high-temperature and high-speed plasma jet. In the spraying process, HA powder is very easy to melt and degrade, so that there are more soluble amorphous HA and calcium phosphate in the coating. After the metal implant is implanted in the human body, these soluble amorphous HA and calcium phosphate are degraded, causing voids and peeling of the coating, which in turn causes the coating to crack and fall off. In this case, a larger coating thickness means that there will be a larger gap between the metal implant and the bone tissue and more HA fragments will be produced, which will cause long-term loosening and inflammation in the implant. At the same time, for metal implants with three-dimensional structures such as voids formed on the surface, plasma spraying is linear spraying, which cannot allow HA to enter the three-dimensional structure, and an overly thick coating may even block the gaps. However, when the HA coating is formed on the surface of the metal implant using the electrochemical deposition method, there are problems that the coating has a poor surface bonding force with the metal implant, the crystallinity of HA particles is low, and the content of soluble calcium phosphate is high.

Summary of the invention

The object of the present invention is to provide a method for depositing hydroxyapatite on a metal surface and a metal implant. The method improves the electrochemical deposition method so that the HA coating and the metal surface have good bonding force to avoid coating. The layer is peeled off, and the HA coating obtained by the method also has the characteristics of high crystallinity and easy control of the thickness of the coating.

In order to achieve the above objective, the present invention provides a method for depositing hydroxyapatite on a metal surface, including:

1) Provide metal substrate;

2) A rough structure is formed on the surface of the metal substrate;

3) Provide electrolyte; and,

4) The metal substrate with the rough structure formed on the surface is placed in the electrolyte, and an electrochemical deposition method is used to form a hydroxyapatite layer on the rough structure; wherein, the raw materials used to prepare the electrolyte include Calcium salt, phosphate and hydrogen peroxide.

Optionally, step 2) of forming a rough structure on the surface of the metal substrate adopts at least one of the following methods:

Method a: Put the metal substrate in a mixed acid solution and react in a water bath at 60°C-70°C for 1h-2h; take out the metal substrate, wash and dry;

Method b: Put the metal substrate in an alkaline solution and react in a water bath at 55°C-65°C for 6h-12h; take out the metal substrate, wash and dry;

Method c: In a fluoride-containing acid solution, the metal substrate is used as the anode, and the inert electrode is used as the cathode. A direct current of 30V-60V is applied between the electrodes, and the reaction is carried out for 15min-60min; take out the metal substrate, clean and dry .

Optionally, in method a, the mixed acid solution is formed by mixing sulfuric acid and hydrochloric acid, and in terms of mass percentage, the concentration of sulfuric acid is 20%-30%, and the concentration of hydrochloric acid is 5%-15%.

Optionally, in method b, the alkaline solution is an aqueous alkali metal hydroxide solution, and the concentration of the alkaline solution is 5 mol/L to 10 mol/L.

Optionally, in method c, in the fluorine-containing acid solution, the concentration of oxo acid is 0.1 mol/L to 1 mol/L, and the concentration of fluoride ion is 0.15 mol/L to 0.3 mol/L.

Optionally, the step 2) of forming a rough structure on the surface of the metal substrate includes:

First proceed to method a, then proceed to method b; or

First proceed to method a, then proceed to method c.

Optionally, the conductivity of the electrolyte is between 1500 μS/cm-2000 μS/cm, the pH is between 5-6.5, and the ratio of calcium to phosphorus in the electrolyte is 1.6-1.7:1, In terms of volume percentage, the concentration of hydrogen peroxide is 6%-12%.

Optionally, the raw material used to prepare the electrolyte in step 3) further includes an ionic compound, and the ionic compound is selected from at least one of ammonium chloride, sodium chloride, and potassium chloride.

Optionally, the phosphate used in preparing the electrolyte in step 3) is selected from ammonium hydrogen phosphate and ammonium dihydrogen phosphate, and the calcium salt used in preparing the electrolyte is selected from calcium acetate and calcium nitrate.

Optionally, in step 4), the electrochemical deposition method includes: using the metal substrate with a rough structure formed on the surface as a cathode, an inert electrode as an anode, and intermittently at 25°C-70°C. A direct current with a constant current is passed between the electrodes to react.

Optionally, the current density of the direct current is 20mA/cm ² -50mA/cm ² , the duration of each energization is 10s-300s, the duration of each power-off is 10s-300s, and the number of energizations is 2-90 The number of power-off times is the same as that of power-on, and the total time of power-on during the whole reaction process is 180s-900s.

Optionally, after step 4), the method further includes post-processing. The post-treatment method includes: first washing the metal substrate after electrochemical deposition with water; then immersing the metal substrate in an alkaline solution for 1h-2h; finally taking out the metal substrate, Wash and dry.

Optionally, before step 2) of forming a rough structure on the surface of the metal substrate, the method further includes: cleaning the metal substrate. The method for cleaning the metal substrate includes: sequential washing, alcohol washing, water washing, acid washing and water washing; wherein the acid washing detergent consists of 20%-40% nitric acid by mass and 3% by mass. Mixed with 5% hydrofluoric acid.

In order to achieve the above object, the present invention also provides a metal implant, including a body, the surface of which is deposited with a hydroxyapatite layer using the aforementioned method. Compared with the prior art, the method for depositing hydroxyapatite on the metal surface and the metal implant of the present invention have the following advantages:

First, the method for depositing hydroxyapatite on the metal surface includes: forming a rough structure on the surface of a metal substrate; placing the metal substrate in an electrolyte, and forming hydroxyapatite on the rough structure by an electrochemical deposition method. Greystone layer; wherein, the raw materials used to prepare the electrolyte include calcium salt, phosphate and hydrogen peroxide. Since the electrolyte contains hydrogen peroxide, during the electrochemical deposition process, the strong oxidizing property of the peroxide radical changes the reduction reaction on the surface of the metal substrate (that is, the electrons from the water molecules generate hydrogen and hydroxide radicals). The reduction reaction of ions becomes a reduction reaction in which hydrogen peroxide obtains electrons to generate hydroxide ions). This makes the reduction reaction of peroxide radicals preferentially occur on the surface of the metal substrate, thereby inhibiting the reduction reaction of hydrogen generated on the surface of the metal substrate, reducing the appearance of pores and fragments in the HA coating, and improving the bonding force between the coating and the surface of the metal substrate. .

Second, by adding ionic compounds such as ammonium chloride to the electrolyte solution to improve the conductivity of the electrolyte, combined with the current with a higher current density for intermittent energization, the purity and crystallinity of HA are improved while further Suppress the generation of hydrogen. The thickness of the HA coating can be controlled by adjusting the single energization duration and the total energization duration (for example, the thickness of the HA coating can be controlled to be 0.5-50μm, preferably less than 5μm) to obtain a suitable thickness of HA coating.

Description of the drawings

FIG. 1 is a scanning electron microscope photograph of the surface of a metal substrate according to Embodiment 1 of the present invention. In the figure, the surface of the metal substrate is formed with a micron-level rough structure, and the magnification of the photograph is 5000 times;

2 is a scanning electron microscope photograph of the surface of a metal substrate provided by the present invention according to Embodiment 1. In the figure, the surface of the metal substrate is formed with an HA coating, and the magnification of the photograph is 50,000 times;

FIG. 3 is an XRD diffraction pattern of the surface of the metal substrate according to Embodiment 1 of the present invention, in which the HA coating is formed on the surface of the metal substrate;

4 is a scanning electron microscope photograph of the surface of a metal substrate according to Embodiment 2 of the present invention. In the figure, the surface of the metal substrate is simultaneously formed with a micron-level rough structure and a nano-level rough structure. The magnification of the photo is 1. Ten thousand times

Figure 5 is a scanning electron micrograph of the surface of the metal substrate provided in Example 2 of the present invention. In the figure, the surface of the metal substrate is formed with both micron-level rough structures and nano-level rough structures. The magnification of the photo is 10 Ten thousand times

6 is a scanning electron micrograph of the surface of the metal substrate provided by the present invention according to Embodiment 2. In the figure, the surface of the metal substrate is formed with an HA coating, and the magnification of the photo is 100,000 times;

FIG. 7 is a scanning electron microscope photograph of the surface of a metal substrate according to Embodiment 3 of the present invention. In the figure, the surface of the metal substrate is formed with a nano-scale rough structure, and the magnification of the photograph is 100,000 times;

FIG. 8 is a scanning electron micrograph of the surface of the metal substrate according to Embodiment 3 of the present invention. In the figure, an HA coating is formed on the surface of the metal substrate, and the magnification of the photograph is 100,000 times;

9 is a scanning electron micrograph of the surface of the metal substrate according to Embodiment 4 of the present invention. In the figure, the surface of the metal substrate is formed with an HA coating, and the magnification of the photo is 100 times;

10 is a scanning electron microscope photograph of the surface of the metal substrate provided in Example 4 of the present invention. In the figure, an HA coating is formed on the surface of the metal substrate, and the magnification of the photograph is 100,000 times;

Figure 11a is a scanning electron microscope photograph of the surface of a metal substrate when the electrochemical deposition temperature is 25° C. according to Example 5 of the present invention. In the figure, the surface of the metal substrate is formed with a HA coating. The magnification of the photograph is 5. Ten thousand times

Figure 11b is a scanning electron micrograph of the surface of the metal substrate when the electrochemical deposition temperature is 40°C according to Example 5 of the present invention. In the figure, the surface of the metal substrate is formed with a HA coating. The magnification of the photo is 5. Ten thousand times

FIG. 12 is a scanning electron micrograph of the surface of the metal substrate according to Embodiment 6 of the present invention. In the figure, an HA coating is formed on the surface of the metal substrate, and the magnification of the photograph is 1000 times;

FIG. 13 is a scanning electron micrograph of the surface of the metal substrate provided in Comparative Example 2. In the figure, a coating is formed on the surface of the metal substrate.

Detailed ways

In order to make the purpose, advantages and features of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

As used in this specification, the singular forms "a", "an" and "the" include plural items unless the content clearly indicates otherwise. As used in this specification, the term "or" is usually used in the meaning including "and/or" unless the content clearly indicates otherwise.

The purpose of this embodiment is to provide a method for depositing hydroxyapatite on a metal surface and a metal implant prepared by the method. The method for depositing hydroxyapatite on the metal surface includes:

Provide metal substrate;

Forming a rough structure on the surface of the metal substrate;

Provide electrolyte; and,

A metal substrate with a rough structure formed on the surface is placed in the electrolyte, and an electrochemical deposition method is used to form a hydroxyapatite layer on the rough structure; wherein, the raw material for preparing the electrolyte includes calcium salt , Phosphate and hydrogen peroxide.

On the one hand, by forming a rough structure on the surface of the metal substrate, the hydrophilicity and biological activity of the surface of the metal substrate can be enhanced, which is beneficial to the deposition of HA particles. On the other hand, due to the addition of hydrogen peroxide in the electrolyte, during the electrochemical deposition process, the strong oxidizing properties of peroxide radicals make the surface of the metal substrate preferentially undergo a reduction reaction of peroxide radicals (ie, hydrogen peroxide Obtain electrons to generate the reduction reaction of hydroxide ions) and inhibit the reduction reaction of hydrogen generation on the surface of the metal substrate (that is, the reduction reaction of generating hydrogen and hydroxide ions from the electrons of water molecules), thereby reducing the appearance of pores in the HA coating And debris to further improve the bonding force between the coating and the surface of the metal substrate.

Generally, for most metal substrates, various particulate matter and grease remain on the surface, as well as the oxide layer formed on the surface of the metal substrate when placed in the air, which are not conducive to the deposition of HA particles. Therefore, before forming a rough structure on the surface of the metal substrate, cleaning the metal substrate may also be included.

Optionally, the cleaning method of the metal implant includes water washing, alcohol washing, water washing, acid washing and water washing in sequence. In detail, first, the metal substrate is rinsed with pure water, isopropanol, and pure water as a cleaning agent in order to remove particulate matter and grease on the metal substrate. During the rinsing process, ultrasonic vibration can also be performed at the same time to improve the cleaning effect. The metal substrate is then placed in a mixed acid solution composed of nitric acid and hydrofluoric acid for pickling to remove the oxide layer on the metal substrate. It should be noted that the time should be controlled during pickling. In terms of mass percentage, the concentration of nitric acid is between 20% and 40%, and the concentration of hydrofluoric acid is between 3% and 5%.

Next, the rough structure is formed on the surface of the metal substrate.

Specifically, the surface of the metal substrate may only form a micron-level rough structure, or only a nano-level rough structure, or form a micron-level rough structure and a nano-level rough structure at the same time. Depending on the forming method, the shape of the nano-scale rough structure may be grid-like or tubular.

There are many options for forming a rough structure on the surface of the metal substrate. This embodiment is only described by way of enumeration, but these methods should not constitute a limitation of the present invention.

Optionally, the following method can be used to form a micron-level rough structure on the surface of the metal substrate: a mixed acid solution is prepared, the mixed acid solution is made by mixing sulfuric acid and hydrochloric acid, and the concentration of sulfuric acid is 20% by mass percentage. Between -30%, the concentration of hydrochloric acid is between 5%-15%. Then, the metal substrate is placed in the mixed acid solution, and the water bath is heated to 60° C.-70° C., and the temperature is kept for 1 hour to 2 hours. Afterwards, the metal substrate is taken out, and the metal substrate is rinsed with pure water, and finally the metal substrate is dried in an oven. Here, the pH of the water that has washed the metal substrate is neutral as the standard for the completion of the cleaning. Hereinafter, the standard for the completion of the cleaning is the same.

Optionally, the following method is used to form a grid-like nano-scale rough structure on the surface of the metal substrate: an alkaline solution is prepared, and the alkaline solution is a strong alkaline concentrated solution. Preferably, the alkaline solution may be an aqueous solution of alkali metal hydroxide, such as sodium hydroxide solution, potassium hydroxide solution, etc., and the concentration of the alkaline solution may be between 5 mol/L and 10 mol/L. Then, the metal substrate is placed in the alkaline solution, and the water bath is heated to 55° C.-65° C., and the reaction is kept for 6 hours to 12 hours. After that, the metal base material is taken out, and the metal base material is washed with pure water, and finally the metal base material is dried.

Optionally, the following method is used to form a tubular nano-scale rough structure on the surface of the metal substrate: a fluorine-containing acid solution is prepared, and the fluorine-containing acid solution is used as an electrolyte, the metal substrate is used as an anode, and the metal substrate is used as an anode. The electrode is a cathode, and a direct current of 30V-60V is applied between the electrodes for reaction, and the reaction time is 15min-60min. After that, the metal base material is taken out, the metal base material is rinsed with pure water, and the metal base material is finally dried. In some embodiments, the fluorine-containing acid solution is formed by mixing oxygen-containing acid and fluorine-containing non-oxygen acid salt. In some other embodiments, the fluorine-containing acid solution is formed by mixing an aqueous hydrogen fluoride solution and an oxyacid. Among them, the oxo acid can be selected from any of phosphoric acid, sulfuric acid, oxalic acid, etc., and the concentration of the oxo acid in the electrolyte can be between 0.1 mol/L and 1 mol/L. The oxygen-free acid salt of fluorine can be sodium fluoride, potassium fluoride, etc., depending on actual needs, but the concentration of fluorine particles in the electrolyte should be between 0.15 mol/L and 0.3 mol/L.

Next, an electrolyte for electrochemical deposition is prepared.

The phosphate used in the preparation of the electrolyte is a soluble phosphate, such as ammonium hydrogen phosphate, ammonium dihydrogen phosphate and the like. Similarly, the calcium salt used in the preparation of the electrolyte is a soluble calcium salt, such as calcium acetate, calcium nitrate and the like. The calcium-phosphorus ratio (molar ratio) in the electrolyte is (1.6-1.7):1, preferably, the calcium-phosphorus ratio is 1.67:1. More specifically, in the embodiment of the present invention, the electrolyte The concentration of calcium ions can be between 1.67 mmol/L and 5 mmol/L, and the concentration of phosphorus atoms can be between 1 mmol/-3 mmol/L. In terms of volume percentage, the concentration of hydrogen peroxide in the electrolyte can be between 6% and 12%.

When preparing the electrolyte, it is also necessary to control the conductivity and pH of the electrolyte. In the prepared electrolyte, the pH is preferably 5-6.5, and the conductivity may be between 1500 μS/cm and 2000 μS/cm.

In this embodiment, the conductivity of the electrolyte can be enhanced by adding ionic compounds to the electrolyte. In an exemplary embodiment, the ionic compound is ammonium chloride, and in the electrolyte, the concentration of the ammonium chloride is between 1 mmol/L and 5 mmol/L. In practice, other ionic compounds such as sodium chloride, potassium chloride, etc. can also be used to control the conductivity of the electrolyte, as long as the conductivity of the electrolyte can reach a predetermined value. However, it should be noted that after adding ionic compounds to the electrolyte, the ratio of calcium to phosphorus in the electrolyte should not be changed, and at the same time, insoluble precipitates should not be generated in the electrolyte. In addition, according to the actual situation, hydrochloric acid, ammonia water and other substances can be used to adjust the pH. It should be known that the conductivity and pH described in this embodiment are all measured at room temperature (ie, normal temperature), where the room temperature is usually 20°C-30°C, such as 20°C, 25°C, and so on.

Further, when preparing the electrolyte, an inert gas can also be passed into the electrolyte to discharge the carbon dioxide in the electrolyte. The inert gas may be nitrogen or other gases that do not participate in the reaction.

Then, electrochemical deposition is performed in the electrolyte to form an HA coating on the surface of the metal substrate.

The specific method of electrochemical deposition includes: using the metal substrate as a cathode, using an inert electrode such as platinum mesh, graphite, etc. as an anode, and intermittently communicating between the electrodes at a temperature of 25°C to 70°C. A direct current with a constant current is applied to perform the reaction, and the current density of the constant current is 20 mA/cm ^{2 to} 50 mA/cm ² . That is to say, during the electrochemical deposition reaction, a current is first applied between the electrodes, and then the current is disconnected, and the power-on and power-off operations are performed at least twice. Generally, the number of repetitions of power-on and power-off operations is less than or equal to ninety times. Optionally, the duration of each power-on is between 10s-300s, and the duration of each power-off is between 10s-300s. Optionally, the total duration of energization during the entire process can be controlled to be 180 s to 900 s, preferably 180 s to 720 s, so as to obtain a HA coating with a suitable thickness. The thickness of the HA coating is preferably 0.5-50 μm, more preferably 0.5-5 μm.

Optionally, during the electrochemical deposition process, the electrolyte solution can be stirred to discharge bubbles in the electrolyte solution, promote the exchange of substances in the electrolyte solution, and improve the efficiency of the reaction. Optionally, for metal substrates with three-dimensional structures such as voids formed on the surface, the electrolytic solution can also be decompressed and exhausted during the electrochemical deposition process.

In this embodiment, a current with a higher current density is used, which can shorten the electrochemical deposition time and improve the purity and crystallinity of the finally obtained HA particles. By intermittently passing current between the electrodes, the generation of hydrogen gas during the reaction is further suppressed, thereby improving the bonding force between the HA coating and the surface of the metal substrate. By controlling the single energization time and the total energization time in the electrochemical deposition process, the thickness of the coating can be conveniently controlled to obtain an ultra-thin HA coating on the surface of the metal substrate.

Preferably, after the electrochemical deposition is completed, post-treatment is also included. The post-treatment process is as follows: firstly, the metal substrate deposited with the HA coating is immersed in pure water for washing; afterwards, it is immersed in an alkaline solution to further promote the crystallization of the deposited HA particles; afterwards, it is immersed in pure water. Wash in water; finally, after drying the surface moisture, place in an oven and dry at 60°C. The alkaline solution is generally a dilute solution, such as a low concentration (for example, 1mol/L) sodium hydroxide solution, potassium hydroxide solution, or a dilute solution of strong alkali and weak acid salts such as sodium carbonate and potassium carbonate. Therefore, the embodiment of the present invention is not limited.

Hereinafter, the preferred embodiments of the method for depositing hydroxyapatite on the metal surface will be described in detail through specific embodiments, but the following embodiments should not limit the present invention.

Example 1

The method for depositing hydroxyapatite on the metal surface described in this embodiment is specifically as follows:

First, a smooth titanium sheet with a side length of 25mm and a thickness of 2mm is provided as the metal substrate.

Next, clean the titanium sheet. Purified water, isopropanol, and pure water are used as cleaning agents in sequence, and ultrasonic vibration is used to clean the titanium sheet, and the cleaning time is 15 minutes each time. Then, the titanium sheet was placed in a mixed solution containing 20% nitric acid and 5% hydrofluoric acid for pickling, and the pickling time was 20 seconds. Finally, rinse the titanium sheet 3-4 times in pure water. Unless otherwise specified herein, "%" refers to mass percentage.

Next, a rough structure is formed on the surface of the titanium sheet. The cleaned titanium sheet was placed in a mixed acid solution containing 24% sulfuric acid and 9% hydrochloric acid, reacted in a water bath at 70° C. for 1 hour, and then washed and dried after being taken out. The SEM scanning analysis was performed on the titanium sheet, and the morphology of the surface of the titanium sheet was obtained as shown in FIG. And the rough structure is a pore structure, and the pore size of the pore structure is about 2-3um.

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 9%. When preparing the electrolyte, nitrogen is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and the pH is adjusted to 5.5 with hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1596 μS/cm.

Next, electrochemical deposition is performed on the surface of the titanium sheet. In the electrolyte, the titanium sheet with the rough structure formed on the surface is used as the cathode, and the graphite electrode is used as the anode for electrochemical deposition. The temperature of the electrochemical deposition is 60°C, and the electrolyte is stirred during the deposition process.

During the electrochemical deposition process, a direct current is applied intermittently between the electrodes, and the current density of the direct current is constant at 50 mA/cm ² , and during the electrochemical deposition process, a total of three power is applied and three power is cut off. That is, in this embodiment, the process of electrochemical deposition includes: power-on, power-off, power-on, power-off, power-on and power-off. And, the duration of each power-on is 300s; the duration of each power-off is 30s.

After that, remove the titanium sheet from the electrolyte and clean it.

Finally, post-processing is performed. The electrochemically deposited titanium sheet was immersed in a 1 mol/L sodium hydroxide solution for 1 hour, and then cleaned, dried naturally, and dried at 60°C.

SEM scanning analysis was performed on the final titanium flakes, and the surface morphology of the titanium flakes is shown in Figure 2. The SEM photo shows that a coating is formed on the surface of the titanium flakes. The length of the coating is about 100-200nm and the diameter is about It is composed of needle-like particles of 30-50nm. Tested by an energy spectrometer (EDS), the calcium to phosphorus ratio of the surface coating on the titanium sheet is 1.67:1, which is consistent with the chemical composition of hydroxyapatite. In other words, a hydroxyapatite coating is formed on the surface of the titanium sheet.

XRD analysis was performed on the surface of the titanium sheet, and the diffraction pattern obtained is shown in Figure 3. In the diffraction pattern, the position of each peak is highly consistent with the characteristic curve of hydroxyapatite. According to the phase purity test method specified in GB23101.3-2010, d=2.88×10 ^-10 m, d=2.905×10 ^-10 m, d=2.995×10 ^-10 m, d=2.405×10 ^-10 m No impurity phase peak was found, and the content of the hydroxyapatite impurity phase was calculated to be 0%. Determine the degree of crystallization of the obtained hydroxyapatite according to the diffraction pattern, and the calculation formula is:

In the formula, X _c is the degree of crystallization (degree of crystallinity), V _112/300 is the intensity of the recess between the (112) peak and the (300) peak, and I ₃₀₀ is the (300) peak intensity.

The crystallization degree of hydroxyapatite in the coating is 0.56 calculated from the above calculation formula.

Example 2

The method of depositing hydroxyapatite on the metal surface described in this embodiment is specifically as follows.

Next, clean the titanium sheet. Purified water, isopropanol, and pure water are used as cleaning agents in sequence, and ultrasonic vibration is used to clean the titanium sheet, and the cleaning time is 15 minutes each time. Then, the titanium piece was placed in a mixed solution containing 40% nitric acid and 3% hydrofluoric acid for pickling, and the pickling time was 20 seconds. Finally, rinse the titanium sheet 3-4 times in pure water.

Next, a rough structure is formed on the surface of the titanium sheet.

In this embodiment, a micron-level rough structure and a nano-level rough structure are formed on the surface of the titanium sheet, and the specific operations are as follows:

Step 1): Put the cleaned titanium sheet in a mixed acid solution containing 30% sulfuric acid and 5% hydrochloric acid, react in a water bath at 65° C. for 1.5 hours, take it out, and wash and dry.

Step 2): Immerse the titanium sheet in a 5mol/L sodium hydroxide solution, react in a water bath at 65°C for 6h, take it out, and wash and dry. SEM scanning analysis was performed on the titanium sheet, and the morphology of the surface of the titanium sheet was shown in Fig. 4 and Fig. 5. The SEM image shows that a micron-level rough structure and a nano-level grid-like structure are formed on the surface of the titanium sheet, and the size of the grid is about 100nm-200nm.

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 6%. When preparing the electrolyte, nitrogen gas is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and the pH of the electrolyte is adjusted to 5.0 through hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1860 μS/cm.

Next, electrochemical deposition is performed on the surface of the titanium sheet. In the electrolyte, the titanium sheet with the rough structure formed on the surface is used as the cathode, and the graphite electrode is used as the anode for electrochemical deposition. The temperature of the electrochemical deposition is 70°C, and the electrolyte is stirred during the deposition process.

During the electrochemical deposition process, a direct current with a constant current density of 40 mA/cm ² is alternately applied between the electrodes, wherein the power is turned on three times and the power is turned off three times. That is, in this embodiment, the electrochemical deposition process is: power-on, power-off, power-on, power-off, power-on and power-off, each power-on duration is 200s; each power-off duration is 100s.

After that, remove the titanium sheet from the electrolyte and clean it.

Next, post-processing is performed. The electrochemically deposited titanium sheet was immersed in a 1 mol/L sodium hydroxide solution for 1 hour, and then cleaned, dried naturally, and dried at 60°C.

SEM scanning was performed on the finally obtained titanium flakes, and the morphology of the surface of the titanium flakes obtained is shown in FIG. 6. The SEM photo shows that the length of the particles deposited on the surface of the titanium sheet is about 100nm-200nm, and the diameter is about 30nm-50nm. Tested by an energy spectrometer (EDS), the calcium to phosphorus ratio of the coating on the surface of the titanium sheet is 1.67:1, which is consistent with the chemical composition of hydroxyapatite. In other words, a hydroxyapatite coating is formed on the surface of the titanium sheet.

Example 3

Next, clean the titanium sheet. Purified water, isopropanol, and pure water are used as cleaning agents in sequence, and ultrasonic vibration is used to clean the titanium sheet, and the cleaning time is 15 minutes each time. Then, the titanium sheet was pickled in a mixed solution containing 30% nitric acid and 5% hydrofluoric acid, and the pickling time was 20 seconds. Finally, rinse the titanium sheet 3-4 times in pure water.

Next, a rough structure is formed on the surface of the titanium sheet. The specific operation is as follows: in the fluoride-containing acid solution, the cleaned titanium sheet is used as the anode, and the graphite electrode sheet is used as the cathode, and the reaction is conducted under a direct current voltage of 60V for 15 minutes. Then take out the titanium sheet and rinse, dry, rinse, and then dry at room temperature. SEM scanning analysis was performed on the titanium sheet, and the surface morphology of the titanium sheet was obtained as shown in FIG. 7. As shown in FIG. 7, the surface of the titanium sheet is formed with a nano-scale tubular rough structure, and the diameter of the nanotube is about 50 nm. In this step, the fluorine-containing acid solution is mixed with phosphoric acid and sodium fluoride, wherein the concentration of phosphoric acid is 1 mol/L and the concentration of sodium fluoride is 0.17 mol/L (that is, the concentration of fluoride ions in the electrolyte is 0.17mol/L).

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of the calcium acetate is 1.7 mmol/L, and the concentration of ammonium dihydrogen phosphate is 1 mmol/L. The concentration of ammonium chloride is 1 mmol/L, and the volume fraction of hydrogen peroxide is 12%. When preparing the electrolyte, nitrogen is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and at the same time, the pH of the electrolyte is adjusted to 5.5 by hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1779 μS/cm.

During the electrochemical deposition process, a direct current with a constant current density of 50mA/cm ² is alternately applied between the electrodes. During the electrochemical deposition process, a total of three power-on and three power-offs are applied, and the duration of each power-on is 300s; The duration of the power outage is 30s.

After that, remove the titanium sheet from the electrolyte and clean it.

SEM scanning analysis was performed on the finally obtained titanium sheet, and the surface morphology of the titanium sheet was obtained as shown in FIG. 8. The SEM photograph shows that a coating with a thickness of less than 1 μm is formed on the surface of the titanium sheet, and the coating is composed of rod-shaped particles with a length of about 200 nm and a diameter of about 20 nm. The EDS test shows that the ratio of calcium to phosphorus in the coating is 1.67:1, which is consistent with the composition of hydroxyapatite, that is, a nano-sized hydroxyapatite coating is formed on the surface of the titanium sheet.

Example 4

First, a 3D printed titanium alloy with a side length of 3cm and a height of 3mm is provided as a metal base. The titanium alloy is Ti ₆ Al ₄ V. The surface of the metal substrate is formed with a pore structure formed by staggered metal rods, and the thickness of the pore structure is about 750 μm, the pore structure of the pore structure is 400 μm, and the diameter of the metal rod is about 200 μm. The "thickness of the pore structure" mentioned here refers to the maximum distance from the last layer of metal powder to the metal substrate during 3D printing.

Next, the metal substrate is cleaned. Pure water, isopropanol, and pure water are used as cleaning agents in sequence, and the metal substrate is rinsed with ultrasonic vibration, and the cleaning time is 15 minutes each time. Then, the titanium alloy is placed in a mixed solution containing 20% nitric acid and 3% hydrofluoric acid for pickling, and the pickling time is 20 seconds. Finally, the titanium alloy is rinsed in pure water 3-4 times.

Next, a rough structure is formed on the surface of the metal substrate.

The specific operation of forming a rough structure on the surface of the metal substrate in this embodiment is as follows:

Step 10): Put the cleaned titanium alloy in a mixed acid solution containing 20% sulfuric acid and 15% hydrochloric acid, react in a water bath at 60° C. for 1 hour, take it out, and wash and dry.

Step 20): Immerse the metal substrate in an 8 mol/L sodium hydroxide solution, react in a water bath at 55° C. for 12 hours, take it out, and wash and dry.

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 12%. When preparing the electrolyte, nitrogen gas is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and the pH of the electrolyte is adjusted to 6.5 through hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1891 μS/cm.

Next, electrochemical deposition is performed on the surface of the titanium alloy. In the electrolyte, a metal substrate with a rough structure formed on the surface is used as a cathode, and a graphite electrode is used as an anode for electrochemical deposition. The temperature of the electrochemical deposition is 60°C, and the electrolyte is stirred during the deposition process. At the same time, the electrochemical deposition in this embodiment is performed in a closed electrolytic cell, and a vacuum pump is connected to the electrolytic cell. During the deposition process, the vacuum pump is turned on to exhaust the gas in the electrolytic cell.

During the electrochemical deposition process, a direct current with a constant current density of 50 mA/cm ² is alternately applied between the electrodes, wherein the current is turned on 30 times and the power is turned off 30 times, and the duration of each energization is 20 s. The duration of the power outage is 10s.

After that, the titanium alloy is taken out from the electrolyte and cleaned.

Finally, post-processing is performed. The electrochemically deposited titanium alloy was immersed in a 1 mol/L sodium hydroxide solution for 1 hour, and then cleaned, dried naturally, and dried at 60°C.

SEM scanning analysis is performed on the finally obtained metal substrate, and the surface morphology of the metal substrate is shown in Figure 9 and Figure 10. At the same time, the EDS test proves that the coating formed on the surface of the metal substrate is a hydroxyapatite coating. It can be clearly seen from the SEM photograph that a hydroxyapatite coating is also formed inside the pore structure, and the hydroxyapatite coating does not block the pore structure.

Example 5

First, two smooth titanium sheets with a side length of 25mm and a thickness of 2mm are provided as the metal substrate.

Next, clean the titanium sheet. Purified water, isopropanol, and pure water are used as cleaning agents in sequence, and oxalic acid vibration is supplemented to clean the titanium sheet, and the cleaning time is 20 minutes each time. Then put the titanium sheet in a mixed solution containing 20% nitric acid and 5% hydrofluoric acid for pickling, and the pickling time is 18 seconds. Finally, the titanium sheet was rinsed in pure water 3-4 times.

Next, a rough structure is formed on the surface of the titanium sheet.

Step 100): Place the cleaned titanium sheet in a mixed acid solution containing 27% sulfuric acid and 15% hydrochloric acid, react in a water bath at 60° C. for 2 hours, take it out, and wash and dry.

Step 200): In a fluoride-containing acid solution, the cleaned titanium sheet is used as an anode, and the graphite electrode sheet is used as a cathode, and the reaction is conducted at a direct current voltage of 30V for 60 minutes. Then take out the titanium sheet and rinse, dry, rinse, and then dry at room temperature. In this step, the fluorine-containing acid solution is mixed with phosphoric acid and sodium fluoride, wherein the concentration of phosphoric acid is 0.1 mol/L and the concentration of sodium fluoride is 0.3 mol/L (that is, the concentration of fluoride ions in the electrolyte Is 0.3mol/L).

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 6%. When preparing the electrolyte, nitrogen is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and at the same time, the pH of the electrolyte is adjusted to 5.5 by hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1920 μS/cm.

Next, electrochemical deposition is performed on the surface of the titanium sheet. The electrolyte is divided into two parts, two titanium sheets with rough structures formed on the surfaces are respectively placed in the two parts of the electrolyte, and the titanium sheets are used as cathodes and graphite electrodes are used as anodes for electrochemical deposition. The temperature of the electrochemical deposition in one part of the electrolyte is 25°C, and the temperature of the electrochemical deposition in the other part of the electrolyte is 40°C. The electrolyte is stirred during the deposition process.

During the electrochemical deposition process, a direct current with a constant current density of 30mA/cm ² is alternately applied between the electrodes, wherein the power is turned on ten times and the power is turned off ten times, and the duration of each power on is 30s; each power off The duration is 10s.

After that, remove the titanium sheet from the electrolyte and clean it.

Next, post-processing is performed. The two titanium sheets after electrochemical deposition were both immersed in a 1 mol/L sodium hydroxide solution for 1 hour, and then cleaned, dried naturally, and dried at 60°C.

SEM scanning was performed on the titanium flakes finally obtained to obtain the surface morphology of the titanium flakes. Among them, Figure 11a shows the surface morphology of the titanium flakes with an electrochemical deposition temperature of 25°C, and Figure 11b shows the electrochemical deposition temperature of 40°C. The surface morphology of the titanium sheet. The SEM photos show that the length of the particles deposited on the surface of the two titanium sheets is about 100nm-200nm, and the diameter is about 30nm-50nm. When the electrochemical deposition temperature is 40°C, the particles deposited on the surface of the titanium sheet have a larger diameter than the particles when the electrochemical deposition temperature is 25°C. Tested by an energy spectrometer (EDS), the calcium to phosphorus ratio of the surface coatings of the two titanium sheets is about 1.67:1, which is consistent with the chemical composition of hydroxyapatite. In other words, hydroxyapatite coatings are formed on the surfaces of the two titanium sheets.

Example 6

First, provide 4 smooth titanium sheets with a side length of 25mm and a thickness of 2mm as the metal substrate.

Next, the titanium sheet is cleaned, and the cleaning method of the titanium sheet is the same as in Example 2.

Next, the same method as in Example 2 is used to form a rough structure on the surface of the cleaned titanium sheet.

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 8%. When preparing the electrolyte, nitrogen gas is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and the pH of the electrolyte is adjusted to 5.7 through hydrochloric acid and ammonia. At this time, the conductivity of the electrolyte was measured to be about 1987 μS/cm.

Next, electrochemical deposition is performed. The electrolyte is divided into four parts, and a piece of titanium sheet with a rough structure formed on the surface is placed in each part of the electrolyte, and the titanium sheet is used as the cathode and the graphite electrode is used as the anode for electrochemical deposition. The deposition process is In each electrolytic cell, a direct current with a constant current density of 20 mA/cm ^{2 was applied intermittently.} The power-on and power-off times in the four electrolytic cells are 20, 50, 70, and 90 times, respectively, each power-on time is 10s, and each power-off time is 10s.

After that, remove the titanium sheet from the electrolyte and clean it. Finally, post-processing is performed, and the specific method of post-processing is the same as the foregoing embodiment.

SEM scan and EDS test were performed on the four final titanium sheets. The SEM scanning photograph of FIG. 12 shows that the surfaces of the four titanium sheets are all formed with hydroxyapatite coatings. SEM scanning analysis was performed on the cross-sections of four samples. The SEM photos show that the thickness of the hydroxyapatite coating of the four samples is 1.16μm (upper left, the number of power-on and off is 20), 2.79μm (upper right, the number of power-on and off is 50), 4.33μm (bottom left) , The number of power-on and power-off is 70 times), 8.06μm (lower right, the number of power-on and power-off is 90 times).

Example 7

Next, a rough structure is formed on the surface of the titanium sheet. The method for forming a rough structure on the surface of the titanium sheet is specifically as follows: immerse the metal substrate in a 10 mol/L sodium hydroxide solution, react in a water bath at 60°C for 8 hours, take it out, and wash and dry.

Next, prepare the electrolyte. The electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the resulting electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, and the concentration of The concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 9%. When preparing the electrolyte, nitrogen is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and at the same time, the pH of the electrolyte is adjusted to 5.5 by hydrochloric acid and ammonia. At this time, the measured conductivity of the electrolyte is about 1980 μS/cm.

Next, electrochemical deposition is performed. In the electrolyte, a metal substrate with a rough structure formed on the surface is used as a cathode, and a graphite electrode is used as an anode for electrochemical deposition. The temperature of the electrochemical deposition is 50°C, and the electrolyte is stirred during the deposition process. At the same time, the electrochemical deposition in this embodiment is carried out in a closed electrolytic cell, and a vacuum pump is connected to the electrolytic cell. During the deposition process, the vacuum pump is turned on to exhaust the gas in the electrolytic cell.

During the electrochemical deposition process, a direct current with a constant current density of 45mA/cm ² is alternately applied between the electrodes, wherein the current is turned on 3 times and the power is turned off 3 times, and the duration of each power-on is 60s, and each time the power is turned off The duration of the electricity is 300s.

After that, remove the titanium sheet from the electrolyte and clean it. Finally, post-processing is performed, and the specific method of post-processing is the same as the foregoing embodiment. SEM scanning and EDS test were performed on the titanium flakes finally obtained, and the results showed that the surface of the titanium flakes was formed with a hydroxyapatite coating.

Comparative example 1

The method of depositing hydroxyapatite on the metal surface of this comparative example is specifically as follows.

First, two smooth titanium sheets with a side length of 25mm and a thickness of 2mm are provided as the metal substrate. Follow the same steps and methods as in Example 6 to clean, roughen the surface and configure electrolyte.

Next, electrochemical deposition is performed. The electrolyte is divided into 2 parts, and a piece of titanium sheet with a rough structure formed on the surface is placed in each part of the electrolyte, and the titanium sheet is used as a cathode and a graphite electrode is used as an anode for electrochemical deposition. Among them, a direct current with a constant current density of 50 mA/cm ^{2 was intermittently passed into the first electrolyte solution.} The number of power-on and power-off is 30 times, each power-on time is 10s, each power-off time is 10s. Continuously pass a direct current with a constant current density of 5 mA/cm ² into the second electrolyte solution for a duration of 30 min.

XRD analysis was performed on the final two titanium sheets, and the degree of crystallization was calculated according to the method in Example 1. The degree of crystallization of the sample obtained under the condition of intermittent high current density was 0.71, and the degree of crystallization of the sample obtained under the condition of continuous low current density was 0.23. It can be seen that the intermittent high current density can significantly increase the crystallinity of the deposited hydroxyapatite.

Comparative example 2

Next, prepare two electrolytes. The first electrolyte is prepared with calcium acetate, ammonium dihydrogen phosphate, ammonium chloride, and hydrogen peroxide as raw materials. In the obtained electrolyte, the concentration of calcium acetate is 5 mmol/L, the concentration of ammonium dihydrogen phosphate is 3 mmol/L, the concentration of ammonium chloride is 5 mmol/L, and the volume fraction of hydrogen peroxide is 8%. When preparing the electrolyte, nitrogen gas is also introduced into the electrolyte to discharge carbon dioxide in the electrolyte, and the pH of the electrolyte is adjusted to 5.7 through hydrochloric acid and ammonia. The preparation method of the second part of the electrolyte is the same as that of the first part, except that the same amount of pure water is used to replace the hydrogen peroxide in the first part of the electrolyte.

Next, electrochemical deposition is performed. A piece of titanium sheet with a rough structure formed on the surface is placed in each portion of the electrolyte, and the titanium sheet is used as the cathode, and the graphite electrode is used as the anode for electrochemical deposition. During the deposition process, electric current is intermittently supplied to each electrolytic cell Direct current with a constant density of 50mA/cm ² , power on 30 times and power off 30 times, each power on time 10s, each power off 10s.

SEM scan and EDS test were performed on the two finally obtained titanium sheets. The SEM photograph in FIG. 13 shows that the hydroxyapatite coating is formed on the surfaces of the two titanium sheets. The comparison of the morphology of the hydroxyapatite layer on the surface of the two titanium sheets shows that the surface of the sample obtained in the first electrolyte with hydrogen peroxide (left picture) is more flat, with almost no bubbles. The surface of the sample obtained in the second electrolyte of hydrogen oxide (pictured on the right) is covered with a large number of broken particles, faults and bubbles, and its surface bonding is poor.

In the embodiment of the present invention, by adding hydrogen peroxide to the electrolyte, the hydrogen generated in the electrochemical deposition process is reduced, hydrogen bubbles are prevented from leaving pores and fragments in the HA particle layer, and the HA coating and the metal base are improved. The bonding force of the surface of the material. During the electrochemical deposition process, high-current-density direct current is provided to the electrode intermittently, which not only improves the purity and crystallinity of HA particles, but also further inhibits the generation of hydrogen, thereby improving the bonding of the HA coating to the surface of the metal substrate. At the same time, it reduces the speed of coating degradation, chipping and peeling, and reduces the risk of implant loosening. In addition, the use of higher current density and shorter deposition time also helps to control the thickness of the particle layer. A thinner coating is easier to enter the three-dimensional structure of the implant surface and will not block the three-dimensional structure of the implant surface. The pores can perfectly retain the well-designed pore structure on the surface of the implant.

The present invention also provides a method for pretreating the surface of a metal substrate, which realizes that the metal substrate has both micron and nanometer roughness, improves the hydrophilicity and biological activity of the surface, facilitates the deposition of nano HA particles, and improves the HA and the surface Binding force.

In addition, after the electrochemical deposition is completed, the metal substrate is also subjected to post-treatment to increase the crystallinity of the HA particles, so that the metal substrate does not need sintering or high-temperature and high-pressure hydrothermal treatment to improve the surface quality and reduce cracks. The surface of the metal implant obtained by the method is formed with a uniform thickness of HA coating, so that the metal implant has good osseointegration ability.

Although the present invention is disclosed as above, it is not limited to this. Those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

A method for depositing hydroxyapatite on a metal surface, which is characterized in that it comprises:

1) Provide metal substrate;

2) A rough structure is formed on the surface of the metal substrate;

3) Provide electrolyte; and,

4) The metal substrate with the rough structure formed on the surface is placed in the electrolyte, and an electrochemical deposition method is used to form a hydroxyapatite layer on the rough structure; The raw materials include calcium salt, phosphate and hydrogen peroxide.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein the step 2) of forming a rough structure on the surface of the metal substrate adopts at least one of the following methods:

Method a: Put the metal substrate in a mixed acid solution and react in a water bath at 60°C-70°C for 1h-2h; take out the metal substrate, wash and dry;

Method b: Put the metal substrate in an alkaline solution and react in a water bath at 55°C-65°C for 6h-12h; take out the metal substrate, wash and dry;

Method c: In a fluoride-containing acid solution, the metal substrate is used as the anode, and the inert electrode is used as the cathode. A direct current of 30V-60V is applied between the electrodes, and the reaction is carried out for 15min-60min; take out the metal substrate, clean and dry .
The method for depositing hydroxyapatite on a metal surface according to claim 2, wherein in method a, the mixed acid solution is formed by mixing sulfuric acid and hydrochloric acid, and the concentration of sulfuric acid is 20% by mass percentage. %-30%, the concentration of the hydrochloric acid is 5%-15%.
The method for depositing hydroxyapatite on a metal surface according to claim 2, wherein in method b, the alkaline solution is an aqueous alkali metal hydroxide solution, and the concentration of the alkaline solution is 5 mol/ L-10mol/L.
The method for depositing hydroxyapatite on a metal surface according to claim 2, characterized in that, in method c, in the fluorine-containing acid solution, the concentration of the oxyacid is 0.1 mol/L-1 mol/L, and the fluorine The concentration of ions is 0.15mol/L-0.3mol/L.
The method for depositing hydroxyapatite on a metal surface according to any one of claims 2-5, wherein the step 2) of forming a rough structure on the surface of the metal substrate comprises:

First proceed to method a, then proceed to method b; or

First proceed to method a, then proceed to method c.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein the conductivity of the electrolyte is between 1500μS/cm-2000μS/cm, the pH is between 5-6.5, and The ratio of calcium to phosphorus in the electrolyte is 1.6-1.7:1, and the concentration of hydrogen peroxide is 6%-12% in terms of volume percentage.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein the raw material used to prepare the electrolyte further includes an ionic compound selected from the group consisting of ammonium chloride, sodium chloride, and chlorine. At least one of potassium chloride.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein the phosphate used when preparing the electrolyte is selected from at least one of ammonium hydrogen phosphate and ammonium dihydrogen phosphate, and The calcium salt used in the electrolyte is selected from at least one of calcium acetate and calcium nitrate.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein in step 4), the electrochemical deposition method comprises: using the metal substrate with a rough structure formed on the surface as a cathode, An inert electrode is used as an anode, and a direct current with a constant current is intermittently passed between the electrodes under the condition of 25° C.-70° C. for reaction.
The method for depositing hydroxyapatite on a metal surface according to claim 10, wherein the current density of the direct current is 20mA/cm 2 -50mA/cm 2 , and the duration of each energization is 10s-300s. The duration of power-off is 10s-300s, and the number of power-on is 2-90 times, the number of power-off is the same as the number of power-on, and the total duration of power-on during the whole reaction process is 180s-900s.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein after step 4), the method further comprises post-treatment; the post-treatment method comprises: first washing with water and electrochemically The deposited metal substrate; then the metal substrate is immersed in an alkaline solution for 1h-2h; finally the metal substrate is taken out, cleaned and dried.
The method for depositing hydroxyapatite on a metal surface according to claim 1, wherein before step 2), the method further comprises: cleaning the metal substrate, and the method for cleaning the metal substrate comprises: Washing with water, alcohol washing, water washing, acid washing and water washing in sequence; wherein, the acid washing detergent is a mixture of 20-40% nitric acid by mass and 3%-5% hydrofluoric acid by mass.
A metal implant is characterized by comprising a body, and the surface of the body is deposited with a hydroxyapatite layer using the method according to any one of claims 1-13.