CN114377198B

CN114377198B - Biodegradable magnesium-based material containing degradable film layer and preparation method and application thereof

Info

Publication number: CN114377198B
Application number: CN202210048693.6A
Authority: CN
Inventors: 齐福刚; 王鑫轩; 戴翌龙; 刘旭辉; 曹红帅; 欧阳晓平; 赵镍; 张德闯
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2022-01-17
Filing date: 2022-01-17
Publication date: 2022-12-20
Anticipated expiration: 2042-01-17
Also published as: CN114377198A

Abstract

The invention discloses a biodegradable magnesium-based material containing a degradable film layer, and a preparation method and application thereof. The biodegradable magnesium-based material consists of a magnesium-based substrate and a pure tin degradable film layer on the surface of the magnesium-based substrate, wherein the thickness of the pure tin degradable film layer is 1-15 mu m; and a metal transition layer is arranged between the magnesium substrate and the pure tin degradable film layer, and the thickness of the metal transition layer is 20 nm-800 nm. The metal transition layer is arranged on the bottom surface of the magnesium-based layer by adopting an ion implantation method; the pure tin degradable film layer is obtained by physical vapor deposition, a layer of protective film is formed on the surface of the substrate of the pure tin film prepared by the two methods, the existence of the protective film improves the corrosion resistance of the magnesium and magnesium alloy substrate, the requirements of uniform corrosion (degradation) and adjustable corrosion (degradation) rate of the surface layer are met, and meanwhile, the surface mechanical property is greatly increased, so that the pure tin degradable film layer is more suitable for being used as a biodegradable material for human body implantation.

Description

Biodegradable magnesium-based material containing degradable film layer and preparation method and application thereof

Technical Field

The invention belongs to the technical field of biomedical metal implant materials, and particularly relates to a biodegradable magnesium-based material containing a degradable film layer, and a preparation method and application thereof.

Background

The biomedical metal material has a series of excellent characteristics of high obdurability, fatigue resistance, easy processing and forming, application reliability and the like, and is the most widely used material of implantation instruments in clinical application. At present, three major types of bio-inert materials, namely stainless steel, titanium and titanium alloy and cobalt-based alloy, are the widest application range, but the three types of bio-inert materials have the following problems in clinical use: (1) non-degradable, requiring a secondary surgical removal: (2) the higher elastic modulus is easy to cause stress shielding effect and influence bone healing; (3) release of toxic ions (e.g., ni ions). It is hoped that some implants can be degraded and absorbed gradually along with the regeneration of tissues or organs after completing medical functions, and finally are removed from the body, so that the degradable implanted metal material is one of the important trends in the research and development of medical metal materials.

In more than ten years, a new generation of medical metal materials represented by degradable medical magnesium alloy develops rapidly and receives wide attention. When the magnesium alloy is used as a bone repair material, the stress shielding effect can be effectively avoided, and the bone healing can be promoted; when the material is used as a vascular stent material, the material can be degraded and disappear in a narrow blood vessel after a period of stent support and positive reconstruction of drug treatment, so that the risk of restenosis 29433is reduced. Therefore, the magnesium alloy has wide clinical application prospect as a degradable medical material and has great application potential in the fields of intraosseous implantation instruments, vascular stents and the like.

The biological magnesium alloy is implanted into a human body to perform chemical reaction with body fluid: mg +2H ₂ O→Mg(OH) ₂ ↓+H ₂ ×) and its corrosion products are mainly magnesium hydroxide and hydrogen, mg (OH) ₂ In Cl ^- Under the action of the catalyst to generate MgCl ₂ And OH ^- Magnesium enters a body fluid and a metabolic circulation system in an ion form, the corrosion process is continuously carried out, and the magnesium alloy is gradually corroded and destroyed until degradation disappears. The standard electrode potential of magnesium is very low (E) ₀ = 2.37 vvshe), thermodynamically very unstable. In the peripheryAt pH values below 11.5, the corrosion rate of the magnesium alloy increases. Therefore, in the human body environment with the pH value of about 7.4, particularly after operation, secondary acid liquid is greatly increased due to human body metabolism, the pH value of body fluid is further reduced, and the corrosion rate of the magnesium alloy is greatly accelerated. At the same time, too rapid corrosion leads to accumulation of magnesium ions, which increase the concentration significantly, leading to muscle paralysis, hypoglycemia, dyspnea and even respiratory arrest. In addition, from the corrosion kinetics point of view, the defect factors such as impurities, second phases and grain boundaries are easy to induce local corrosion cracking, which leads to stress concentration at the corrosion part to initiate fracture, early loss of the supporting function and finally failure of the operation. The controlled degradation of the magnesium implant in the human body can only be achieved by uniform corrosion, thereby directing the structural design. Therefore, how to reduce the corrosion rate of biological magnesium alloy and change the corrosion mode to achieve controlled degradation is a hotspot and difficulty of current research.

At present, in order to improve the problem of too fast corrosion of magnesium alloy, researchers mostly adopt alloying and surface treatment, wherein the surface treatment is the most effective and common approach. The surface treatment method is the micro-arc oxidation, but the film layer obtained by the micro-arc oxidation is not compact enough, and the obtained ceramic coating cannot be degraded in a human body. The problems of over-fast corrosion rate and non-uniform corrosion need to be solved.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a biodegradable magnesium-based material containing a pure tin degradable film layer, and a preparation method and application thereof, wherein the degradable film layer has excellent biocompatibility, has excellent film-substrate binding force with a magnesium alloy matrix, and can improve the corrosion resistance and mechanical property of a magnesium alloy biological implantation material.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention relates to a biodegradable magnesium-based material containing a pure tin degradable film layer, which consists of a magnesium-based substrate and the pure tin degradable film layer on the surface of the magnesium-based substrate, wherein the thickness of the pure tin degradable film layer is 1-15 mu m.

The inventor finds that the problem of excessively fast corrosion degradation and non-uniform corrosion of the biodegradable magnesium-based metal in the human body environment can be effectively solved by arranging a layer of pure tin film on the surface of the biodegradable magnesium-based metal, so that the biodegradable magnesium-based metal is degraded in the human body at a proper rate. Tin is one of the trace elements essential to human body, has good biocompatibility, is related to yellow enzyme activity, and can promote the reaction of protein and nucleic acid and further promote growth and development. Tin promotes the decomposition of hemoglobin, thereby affecting the function of hemoglobin. Most importantly, tin can promote tissue growth and wound healing and can participate in energy metabolism.

Preferably, a metal transition layer is further arranged between the magnesium substrate and the pure tin degradation film layer, and the metal in the metal transition layer is selected from one of pure copper, pure iron, pure zinc, pure cobalt, pure manganese, pure vanadium and pure tin, and is preferably pure tin.

More preferably, the thickness of the metal transition layer is 20nm to 800nm, preferably 50 to 200nm.

There are many ways in which the metal transition layer can be formed, and any of the ways in the prior art in which the metal transition layer can be formed is suitable for use in the present invention.

Further preferably, the metal transition layer is disposed on the bottom surface of the magnesium base by ion implantation.

The inventor finds that after the metal transition layer is arranged by adopting an ion implantation method, the degradation performance of the finally obtained biodegradable magnesium-based material is optimal, because the ion implantation process is an unbalanced process, the implanted elements are not limited by diffusion coefficient, solid solubility and equilibrium phase diagram, no interface exists between the implanted layer and the substrate, metallurgical bonding can be formed, and the bonding strength between the implanted layer and the substrate is high and the adhesiveness is good. Meanwhile, because high-energy ions are forcibly injected into the surface of the workpiece, a large amount of interstitial atoms, vacancies and dislocations are generated, so that the surface is strengthened, and the fatigue life is prolonged. The ion implantation is carried out under high vacuum and lower process temperature, so that the workpiece does not generate oxidation and decarburization phenomena and has no obvious dimensional change. Of course, the thickness of the film formed by ion implantation is limited, and the formed workpiece generally requires subsequent heat treatment to remove the dislocations due to the presence of a large number of dislocations. Therefore, the ion-implanted layer is used only for providing the transition layer.

In a preferred scheme, the pure tin degradable film layer is obtained by physical vapor deposition.

The inventor finds that the transition layer is arranged by adopting an ion implantation method, and then the pure tin degradation film layer is arranged by adopting an ion deposition mode, so that the bonding force of the film layer is good, the thickness of the film layer can be increased, and the long service life in a human body can be met without carrying out subsequent treatment on a sample.

However, the inventors found that the thickness of the pure tin degradation film needs to be effectively controlled, and if the thickness of the pure tin degradation film is too thick, the corrosion resistance of the sample may be adversely affected due to the increase of residual stress.

In a preferable scheme, the thickness of the pure tin degradation film layer is 5-9 μm.

Within this preferred range, the properties of the finally obtained biodegradable magnesium-based material are optimal.

Preferably, the magnesium substrate is selected from at least one of WE43 magnesium alloy, pure magnesium and Mg-X alloy, wherein X in the Mg-X alloy is selected from at least one of Zn, ca, sr and Zr.

The invention relates to a preparation method of a biodegradable magnesium-based material containing a pure tin degradable film layer, which is characterized in that the pure tin degradable film layer with the thickness of 1-15 mu m is obtained on the surface of a magnesium-based substrate through physical vapor deposition, and the biodegradable magnesium-based material is obtained.

In a preferred scheme, the magnesium substrate is mechanically polished and then ultrasonically cleaned for more than 15min by acetone and absolute ethyl alcohol respectively. By this pretreatment, all magnesium-based bottom surfaces are cleaned and dried.

Preferably, the ion implantation method is adopted to arrange a transition layer with the thickness of 20 nm-800 nm on the bottom surface of the magnesium-based substrate, and then the pure tin degradation film layer with the thickness of 1-15 mu m is obtained by physical vapor deposition growth on the surface of the transition layer.

More preferably, the ion implantation method is a MEVVA ion source implantation method, and the time for ion implantation is 4 to 10min.

Preferably, the physical vapor deposition method is one selected from a magnetic filtration cathode vacuum arc ion beam deposition method, a multi-arc ion plating method and a magnetron sputtering method, and is preferably a magnetic filtration cathode vacuum arc ion beam deposition method.

Further preferably, when the physical vapor deposition method is a magnetic filtration cathode vacuum arc ion beam deposition method, the deposition process of the pure tin degradation film layer is as follows: sn source with purity of more than or equal to 99 percent is used as an arc source, and before the deposition of the magnetic filtering cathode vacuum arc ion beam, the pressure intensity of a vacuum chamber in the magnetic filtering cathode vacuum arc deposition equipment is controlled to be 3.0-4.0 multiplied by 10 ^-3 Pa; when the magnetic filtration cathode vacuum arc deposition is carried out, the arc starting current is controlled to be 90-120A, the magnetic field of a bent pipe is controlled to be 1.5-3.0A, the magnetic field of a straight pipe is 2.0-4.0A, the beam intensity is 350-400 mA, and the duty ratio is 40-90%; depositing by sequentially adopting-800V, -600V, -400V and-200V, depositing for 20-40 s at each negative pressure point, and depositing for 10-30 min when the negative pressure is-100V after-200V deposition is finished; obtaining the pure tin degradation film layer.

The inventor finds that the pure tin degradation film layer obtained by adopting the magnetic filtration cathode vacuum arc ion beam deposition (FCVA) technology has optimal final performance, because the types of the particles are screened by a magnetic field before the particles are deposited on the alloy, the components which destroy the quality of the film layer are removed, and the film layer formed on the alloy has uniform and stable structure, high compactness and less defects; under the action of a magnetic field formed by applying negative bias, the charged high-energy ions generate bombardment sputtering action to a certain degree on the substrate of the alloy table, so that the film-substrate interface is firmly combined and is not easy to fall off; the ionization rate of the target material is high, the deposition film forming speed is higher, and the working efficiency is high; the deposition temperature is relatively low, so that the change of the structural performance of the substrate caused by overhigh temperature in the working process is avoided.

Magnetic filtered cathode vacuum arc ion beam deposition was performed in an FCVA system. The FCVA system comprises an FCVA vacuum lock coating system and certainly also comprises an FCVA vacuum coating continuous production line.

Further preferably, when the physical vapor deposition method is a multi-arc ion plating method, the deposition process of the pure tin degradation film layer is as follows: mounting a magnesium base on a substrate table of multi-arc ion plating equipment as an anode, and mounting a tin target into a multi-arc ion plating arc head as a cathode; vacuum degree is pumped to 3 × 10 ^-3 ～6×10 ^-4 After Pa, introducing argon to stabilize the pressure in the multi-arc ion plating to 0.1-0.9 Pa, and then preheating the magnesium substrate to 50-200 ℃; controlling the discharge voltage to be 10V-30V, the current to be 60A-90A and the deposition rate to be 3-5 mu m/min; depositing for 5-15 min to obtain the pure tin degradable film.

Further preferably, when the physical vapor deposition method is a magnetron sputtering method, the deposition process of the pure tin degradation film layer is as follows: mounting a magnesium substrate on an anode plate of a magnetron sputtering instrument; then putting the tin target into a magnetron sputtering instrument as a cathode; the vacuum degree is pumped to 10 ^-2 ～10 ^-3 After Pa, introducing argon to stabilize the pressure in the magnetron sputtering instrument at 1-10 Pa; then preheating the magnesium substrate to 20-200 ℃; controlling the discharge voltage to be 280V-350V, the current to be 0.2A-0.6A, the deposition rate to be 0.5-1.2 mu m/min and the deposition time to be 10-20 min to obtain the pure tin degradation film.

The invention also provides application of the biodegradable magnesium-based material containing the pure tin degradable film layer, and the biodegradable magnesium-based material containing the pure tin degradable film layer is used as a biomedical metal implant material.

Principles and advantages

(1) Aiming at the problems of over-high degradation rate and non-uniform corrosion of magnesium and magnesium alloy, the corrosion resistance of magnesium is improved by adopting a magnesium alloying mode in the prior art, but the degradation rate cannot be improved by adopting the mode, and the non-uniform corrosion problem still exists, in order to solve the problems, people also adopt a surface treatment mode for magnesium and magnesium alloy, but the common surface treatment mode has certain limitations for the application of magnesium and magnesium alloy which needs to be implanted into a human body, such as: micro-arc oxidation leaves micro-pores on the surface of the film layer, which can act as channels for corrosive media to enter the substrate. Not conducive to improvement of corrosion resistance and uniform corrosionAnd (5) realizing. The chemical plating method can cause environmental pollution in the production process, and heavy metal ions Cr harmful to human bodies can be generated in the preparation process ⁶⁺ . Therefore, the invention selects proper surface treatment process, and can prepare high-purity metal film with low degradation rate on the surface of biological magnesium and magnesium alloy according to the degradation corrosion rate of different metals, thereby not only solving the problem of over-high degradation rate of magnesium and magnesium alloy, but also realizing controlled decomposition under uniform corrosion.

(2) Physiological stress is an important component of human metabolism, is closely related to bone tissue reconstruction, blood circulation, body fluid flow and the like, and especially plays an important role in the bone tissue injury healing process. In service, the implant device will inevitably be subjected to physiological stresses, which are believed to affect the degradation behavior of the material and thus the service behavior of the implant device (e.g., resulting in a device having a service life less than expected). The pure metal film layer has the characteristics of good plasticity and toughness, can effectively resist the action of physiological stress and delay the degradation speed of magnesium and magnesium alloy in human body. And the pure metal film layer can realize uniform corrosion in a human body, so that the defect that the implanted material fails prematurely due to the loss of mechanical properties caused by non-uniform corrosion can be avoided, and the implanted material can meet the long-term service effect in the human body.

(3) The inventor finds that a pure tin layer is arranged on the surface of magnesium and magnesium alloy through a large number of experiments, the finally obtained biodegradable magnesium-based material is degraded at the most appropriate rate in a human body, tin is one of essential trace elements of the human body, has good biocompatibility, and is related to yellow enzyme activity, so that the protein and nucleic acid reaction can be promoted, and the growth and development are further promoted. Tin promotes the decomposition of hemoglobin, thereby affecting the function of hemoglobin, and most importantly, tin promotes tissue growth and wound healing and participates in energy metabolism.

(4) However, the single physical vapor deposition process can achieve the deposition of metal ions on the substrate, but the bonding force between the deposited metal ions and the substrate is not very ideal. The introduction of the transition layer can effectively improve the bonding force, and the inventors found that when the transition layer is formed by ion implantation, the finally prepared biodegradable magnesium-based material has the best performance, and the ion implantation can be used as a surface treatment process, and can also be used as an auxiliary process to be used as the transition layer to improve the bonding force of the film and the substrate. Under the action of an electrostatic field with a voltage of ten to hundreds of kilovolts in high vacuum, accelerated high-energy particles impact a surface to be treated and are injected into a sample to form a pinning effect. The injected particles are neutralized and remain in the sample solid solution at the vacancy or interstitial sites, forming a non-equilibrium surface layer. The ion implantation can form a new alloy layer on the surface, change the surface state and solve the problem of the bonding strength between the coating prepared by other processes and the substrate. The ion implantation and the ion deposition can be carried out together, so that the film has good bonding force, the thickness of the film can be increased, and the subsequent treatment of the sample is not needed. Can meet the long service life in the human body.

(5) With respect to physical vapor deposition to obtain pure tin films, the preferred FCVA technology of the present invention has the following advantages over conventional deposition techniques: before the particles are deposited on the alloy, the types of the particles are screened by a magnetic field, and components which damage the quality of the film layer are removed, so that the film layer formed on the alloy has uniform and stable structure, high density and less defects; under the action of a magnetic field formed by external negative bias, the charged high-energy ions generate a certain bombardment sputtering effect on the substrate of the alloy table, so that the film-substrate interface is firmly combined and is not easy to fall off; the ionization rate of the target material is high, the deposition film forming speed is higher, and the working efficiency is high; the deposition temperature is relatively low, so that the change of the structural performance of the substrate caused by overhigh temperature in the working process is avoided; the device is simple and convenient to operate, extra working gas is not needed in the chamber during working, and reaction gas can be introduced to participate in the film forming process when experimental requirements exist.

(6) The preferred MEVVA injection and FCVA deposition technology can obtain the biodegradable magnesium and magnesium alloy with the tin film by adjusting experimental parameters such as bent pipe magnetic field current, straight pipe magnetic field current, negative pressure, duty ratio, deposition time, modulation period and the like, and the total thickness can reach 1-16 mu m.

In conclusion, the tin film prepared on magnesium and magnesium alloy disclosed by the invention has the following advantages:

(1) The proper surface treatment process selected by the invention does not cause any pollution to the environment and does not introduce any element harmful to human bodies. According to the degradation corrosion rate of different metals, a high-purity metal film with low degradation rate can be prepared on the surface of the biological magnesium alloy, so that the problem of excessively high degradation rate of magnesium and magnesium alloy can be solved, and controlled decomposition under uniform corrosion can be realized.

(2) The pure metal film layer has the characteristic of good plasticity and toughness. Can effectively resist the action of physiological stress. And the pure metal film layer can realize uniform corrosion in a human body.

(3) The invention firstly applies the preparation process of preparing the Sn film by the composite coating on the surfaces of the biodegradable magnesium and magnesium alloy, and the film layer is firmly combined with the substrate through the transition layer formed by ion implantation, thereby effectively prolonging the service life of the biodegradable magnesium and magnesium alloy. By adjusting the parameters of the ion deposition process, the defect that the biodegradable magnesium and magnesium alloy are degraded too fast in a human body is overcome.

(4) Compared with other PVD and CVD deposition methods, the FCVA of the preferred scheme of the invention has the advantages of high equipment atom ionization rate, magnetic filtering device, greatly reduced large particles during film formation, and improved compactness and uniformity of the film.

(5) The FCVA technology of the preferred scheme of the invention has the advantages of environmental protection, no pollution to the ecological environment, high deposition rate, large-area deposition and the like, and has very wide application value in the field of human body implant materials.

In a word, the tin film injected and deposited on the biodegradable magnesium and magnesium alloy designed by the invention can obviously improve the corrosion resistance of the biodegradable magnesium and magnesium alloy, effectively prolong the service life of the biodegradable magnesium and magnesium alloy in a human body and meet the requirement of implanting metal materials into the human body.

Drawings

FIG. 1 is a schematic representation of a WE43 biodegradable magnesium alloy with a tin film on the surface in example 1.

FIG. 2 is a surface film diagram of the WE43 biodegradable magnesium alloy of example 1 with a tin film on the surface.

Fig. 3 is a side view of the interface of the film of the WE43 biodegradable magnesium alloy with a tin film on the surface in example 1.

FIG. 4 is an AFM image of a WE43 biodegradable magnesium alloy with a tin film on the surface in example 1.

Fig. 5 is a XRD comparison pattern of the WE43 biodegradable magnesium alloy having a tin film on the surface thereof and the substrate WE43 biodegradable magnesium alloy of example 1.

FIG. 6 is a typical load-displacement curve of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate in example 1.

FIG. 7 is a polarization diagram of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate in the SBF solution in example 1.

FIG. 8 shows the surface topography of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate in the SBF solution for 3h in example 1. Wherein FIG. 8 (a) is: FESEM image of substrate at 500 x magnification, fig. 8 (b) is: FESEM of the substrate at 5000 × magnification, fig. 8 (c) FESEM of WE43 with a Sn thin film on the surface at 500 × magnification: fig. 8 (d) is an FESEM image of WE43 with a Sn thin film on the surface at 5000 × magnification.

Fig. 9 is a schematic structural view of the biodegradable magnesium-based material of example 2.

Detailed Description

The technical scheme of the invention is described in detail by combining the description of the attached drawings, and the described examples are only part of the embodiments of the invention obviously. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technology for depositing tin on the surface of biological magnesium and magnesium alloy, and in order to realize the purpose of the invention, the technical scheme mainly comprises two steps: firstly, pretreatment; the second is a preparation process. Wherein the preparation process is different, and the pretreatment is completely the same. The pretreatment mainly comprises the following steps:

(1) Pretreatment of a vacuum chamber of the FCVA system: before magnesium and magnesium alloy are put into a vacuum chamber, a dust collector is used for completely sucking dust and attachments remained in the vacuum chamber, and a sample table is wiped by absolute ethyl alcohol and gauze;

(2) Pretreatment of magnesium and magnesium alloy substrates: and (3) polishing the surfaces of the magnesium and magnesium alloy substrates to remove oxides on the surfaces, cleaning the surfaces by using alcohol, quickly drying the surfaces by using a blower, putting the surfaces on a sample table of a processed vacuum chamber, and closing the vacuum chamber.

(3) Before the film coating is started, the vacuum degree of the FCVA system is 1.0-1.0 multiplied by 10 ^-3 Pa。

The preparation process will be described below by way of specific examples:

example 1

The method comprises the steps of taking WE43 biodegradable magnesium alloy as a substrate, adopting an FCVA system, starting a tin power supply arc, adjusting an arc starting voltage to be 120A, adjusting a bent pipe magnetic field to be 2.0A, adjusting a straight pipe magnetic field to be 3.5A, adjusting a duty ratio to be 90%, sequentially adopting-800V, -600V, -400V and-200V for deposition, depositing for 20-40 s at each negative pressure point, and depositing for 20min when the negative pressure is-100V after-200V deposition is completed; thus obtaining the WE43 biodegradable magnesium alloy with a layer of tin film on the surface.

FIG. 1 is a schematic diagram of a WE43 biodegradable magnesium alloy with a tin film on the surface according to the embodiment. FIG. 2 is a surface film diagram of the WE43 biodegradable magnesium alloy with a tin film on the surface. FIG. 3 is a side view of the biodegradable magnesium alloy WE43 with a tin film on the surface. FIG. 4 is an AFM image of a WE43 biodegradable magnesium alloy with a tin film on the surface, which is rougher in the surface. Fig. 5 is a XRD comparison graph of the WE43 biodegradable magnesium alloy with a tin film on the surface thereof and the substrate WE43 biodegradable magnesium alloy, which shows that a pure tin film is formed on the surface of the substrate after FCVA process. It can be known that the WE43 biodegradable magnesium alloy with the tin film on the surface obtained by the FCVA method has the same structure as the expected design structure, meets the design requirements, and indicates that the preparation process is reliable. As can be seen from the side view of the film layer, the thickness of the film layer was 8.7 μm.

FIG. 6 is a typical load-displacement curve of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate. The elastic modulus and hardness were calculated according to the Oliver Pharr method. The elastic modulus and hardness of the magnesium alloy were 64.01GPa and 0.32GPa, respectively. The elastic modulus and hardness of the sample subjected to the ion deposition coating treatment were 46.64GPa and 1.15GPa, respectively. The elastic modulus of the sample subjected to the ion deposition coating treatment is larger than that of WE 43.

FIG. 7 is a polarization diagram of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate in the SBF solution. Ecorr and Icorr derived from Tafel curves are shown in the table. After ion deposition coating treatment, ecorr of WE43 is improved from-1.89V to-1.47V. It is well known that higher Ecorr means lower corrosion tendency. Icor of WE43 is coated with ion deposition and then is coated with film from 60 muA cm ^-2 Reduced to 7.6 muA cm ^-2 . The sample after the ion deposition coating treatment has higher Ecorr and lower Icorr than WE43, which shows that the sample after the ion deposition coating treatment has better corrosion resistance than WE 43. The surface is provided with a layer of Sn film which can play a role of separating corrosive liquid from a matrix, thereby reducing the possibility of pitting corrosion, and the treated sample has better corrosion resistance.

FIG. 8 is a surface appearance of the WE43 biodegradable magnesium alloy with a tin film on the surface and the substrate of the present embodiment immersed in the SBF solution for 3 hours. As can be seen from the figure, the WE43 substrate has serious surface corrosion, the surface is seriously cracked, and corrosion pits are distributed on the surface of the sample. These corrosion pits can act as channels for the entry of corrosive solutions, causing further aggravation of the corrosion of the WE43 substrate. The treated sample surface did not change much, with only slight corrosion, and a small portion of the area cracked. According to the analysis, most Sn is occupied in the cracked part, no corrosion product is generated, and the corrosion liquid does not corrode the matrix. The results show that a dense Sn film formed by ion-deposited Sn plays a critical role in protecting against corrosion.

Example 2:

the WE43 biodegradable magnesium alloy is used as a substrate, and a layer of Sn film is injected on the WE43 biodegradable magnesium alloy substrate by using a MEVVA system for 9min. A pure tin transition layer with a thickness of 100nm is obtained.

Then, opening a tin power supply arc by adopting an FCVA system, adjusting the arc starting voltage to be 120A, adjusting the arc starting voltage to be 2.0A, adjusting the magnetic field of a bent pipe to be 3.5A, adjusting the duty ratio to be 90%, depositing by adopting-800V, -600V, -400V and-200V in sequence, depositing for 20-40 s at each negative pressure point, and depositing for 20min when the negative pressure is-100V after-200V deposition is finished; the biodegradable magnesium having a tin film with a thickness of 8.9 μm on the surface was obtained.

According to the Tafel curve, due to the existence of a layer of injected Sn film, I _corr The reduction was 1 μ A.

Example 3:

the method comprises the steps of opening a tin power supply arc by adopting a biodegradable magnesium substrate and an FCVA system, adjusting an arc starting voltage to be 120A, adjusting a bent pipe magnetic field to be 2.0A, adjusting a straight pipe magnetic field to be 3.5A, adjusting a duty ratio to be 90%, sequentially adopting-800V, -600V, -400V and-200V for deposition, depositing for 20-40 s at each negative pressure point, and depositing for 20min when the negative pressure is-100V after-200V deposition is completed; obtaining the biodegradable Mg-Zn alloy with a layer of tin film on the surface.

As can be seen from the side view of the film layer, the thickness of the film layer was 8.5. Mu.m. According to the Tafel curve, I _corr The reduction is 29 muA cm ^-2 。

Example 4:

the method comprises the steps of taking biodegradable Mg-Zn alloy as a substrate, opening a tin power supply arc by adopting an FCVA system, adjusting the arc striking voltage to be 120A, adjusting the bent tube magnetic field to be 2.0A, adjusting the straight tube magnetic field to be 3.5A, adjusting the duty ratio to be 90%, sequentially adopting-800V, -600V, -400V and-200V for deposition, depositing for 20-40 s at each negative pressure point, and depositing for 20min when the negative pressure is-100V after-200V deposition is completed; obtaining the biodegradable Mg-Ca alloy with a layer of tin film on the surface.

The film thickness was 8.1 μm as shown by the side view of the film, and I is shown by Tafel plot _corr The reduction is 20 muA cm ^-2 。

Example 5:

the method comprises the steps of taking biodegradable Mg-Ca alloy as a substrate, opening a tin power supply arc by adopting an FCVA system, adjusting the arc striking voltage to be 120A, adjusting the bent pipe magnetic field to be 2.0A, adjusting the straight pipe magnetic field to be 3.5A, adjusting the duty ratio to be 90%, sequentially adopting-800V, -600V, -400V and-200V for deposition, depositing for 20-40 s at each negative pressure point, and depositing for 20min when the negative pressure is-100V after-200V deposition is completed; obtaining the biodegradable Mg-Ca alloy with a layer of tin film on the surface.

As can be seen from the side view of the film layer, the film thickness was 8.3 μm, and from the Tafel plot, I _corr The reduction is 18 muA cm ^-2 。

Example 6:

adopting WE43 biodegradable magnesium alloy as a substrate, adopting a multi-arc ion plating system, installing biodegradable magnesium on a substrate table of multi-arc ion plating equipment as an anode, and installing a tin target in a multi-arc ion plating arc head as a cathode; vacuum degree is pumped to 2 x 10 ^-3 After Pa, introducing argon to stabilize the pressure in the multi-arc ion plating within the range of 0.2 Pa; secondly, the method comprises the following steps: preheating the base material to 100 ℃; the discharge voltage is 20V, the current is 80A, and the deposition rate is 3 mu m/min; deposition time of the droplets under these conditions was 15 minutes;

according to the Tafel curve, I _corr The reduction is 20 muA cm ^-2 。

Example 7:

adopting the optimized WE43 biodegradable magnesium alloy as a substrate, and installing the WE43 biodegradable magnesium alloy on an anode plate of a magnetron sputtering instrument by adopting a magnetron sputtering system; putting the tin target into a magnetron sputtering instrument as a cathode; the vacuum degree is reduced to 10 ^- ³ After Pa, introducing argon to stabilize the pressure in the magnetron sputtering instrument within a range of 10Pa; preheating the base material to 200 ℃; the discharge voltage is 350V, the current is 0.2A, the deposition rate is 1.2 mu m/min, and the surface tin film deposition is carried out under the condition;

according to the Tafel curve, I _corr The reduction is 30 muA-cm ^-2 。

Example 8:

adopting WE43 biodegradable magnesium alloy as a substrate, adopting an FCVA system, opening a tin power supply arc, adjusting the arc starting voltage to be 120A, adjusting the magnetic field of a bent pipe to be 2.0A, adjusting the magnetic field of a straight pipe to be 3.5A, adjusting the duty ratio to be 90%, sequentially adopting-800V, -600V, -400V and-200V for deposition, depositing for 20-40 s at each negative pressure point, and depositing for 25min when the negative pressure is-100V after-200V deposition is finished; thus obtaining the WE43 biodegradable magnesium alloy with a tin film on the surface.

As can be seen from the side view of the film layer, the film layer thickness was 9.1. Mu.m. From the Tafel plot, icorr was reduced to 15. Mu.A. Cm ^-2 。

It should be understood by those skilled in the art that the foregoing examples are merely illustrative of the present invention and that various modifications and changes may be made in the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims

1. A biodegradable magnesium-based material containing a pure tin degradable film layer is characterized in that: the biodegradable magnesium-based material consists of a magnesium-based substrate and a pure tin degradable film layer on the surface of the magnesium-based substrate, wherein the thickness of the pure tin degradable film layer is 5-9 mu m;

a metal transition layer is arranged between the magnesium substrate and the pure tin degradation film layer, metal in the metal transition layer is selected from one of pure copper, pure iron, pure zinc, pure cobalt, pure manganese, pure vanadium and pure tin, and the thickness of the metal transition layer is 20 nm-800 nm;

the metal transition layer is arranged on the bottom surface of the magnesium-based layer by adopting an ion implantation method; the pure tin degradation film layer is obtained by physical vapor deposition;

the magnesium substrate is selected from at least one of WE43 magnesium alloy, pure magnesium and Mg-X alloy, wherein X in the Mg-X alloy is selected from at least one of Zn, ca, sr and Zr.

2. The preparation method of the biodegradable magnesium-based material containing the pure tin degradable film layer according to claim 1, which is characterized in that: firstly, arranging a transition layer with the thickness of 20 nm-800 nm on the bottom surface of the magnesium base by adopting an ion implantation method, and then obtaining a pure tin degradation film layer with the thickness of 5-9 mu m on the surface of the transition layer through physical vapor deposition.

3. The preparation method of the biodegradable magnesium-based material containing the pure tin degradable film layer according to claim 2, wherein the preparation method comprises the following steps: the magnesium substrate is mechanically polished and then ultrasonically cleaned for more than 15min by acetone and absolute ethyl alcohol respectively.

4. The preparation method of the biodegradable magnesium-based material containing the pure tin degradable film layer according to claim 2, wherein the preparation method comprises the following steps: the ion implantation method is an MEVVA ion source implantation method, and the ion implantation time is 4-10 min.

5. The preparation method of the biodegradable magnesium-based material containing the pure tin degradable film layer according to claim 2, wherein the preparation method comprises the following steps: the physical vapor deposition method is selected from one of a magnetic filtration cathode vacuum arc ion beam deposition method, a multi-arc ion plating method and a magnetron sputtering method.

6. The preparation method of the biodegradable magnesium-based material containing the pure tin degradable film layer according to claim 2, wherein the preparation method comprises the following steps:

when the physical vapor deposition method is a magnetic filtration cathode vacuum arc ion beam deposition method, the deposition process of the pure tin degradation film layer is as follows: sn source with purity more than or equal to 99 percent is used as an arc source, and before the deposition of the magnetic filtration cathode vacuum arc ion beam, the pressure intensity of a vacuum chamber in the magnetic filtration cathode vacuum arc deposition equipment is controlled to be 3.0-4.0 multiplied by 10 ^-3 Pa; during magnetic filtration cathode vacuum arc deposition, arc starting current is controlled to be 90-120A, a bent pipe magnetic field is controlled to be 1.5-3.0A, a straight pipe magnetic field is controlled to be 2.0-4.0A, beam intensity is controlled to be 350-400 mA, and duty ratio is controlled to be 40-90%; depositing by sequentially adopting-800V, -600V, -400V and-200V, depositing for 20-40 s at each negative pressure point, and depositing for 10-30 min when the negative pressure is-100V after-200V deposition is finished; obtaining a pure tin degradable film layer;

when the physical vapor deposition method is a multi-arc ion plating method, the deposition process of the pure tin degradation film layer is as follows: mounting a magnesium base on a substrate table of multi-arc ion plating equipment as an anode, and mounting a tin target into a multi-arc ion plating arc head as a cathode; vacuum degree is pumped to 3 × 10 ^-3 ～6×10 ^-4 After Pa, introducing argon to stabilize the pressure in the multi-arc ion plating to 0.1-0.9 Pa, and then preheating the magnesium substrate to 50-200 ℃; controlling the discharge voltage to be 10V-30V and the current to be 60A-90A, wherein the deposition rate is 3-5 mu m/min; depositing for 5-15 min to obtain the pure tin degradable film;

when the physical vapor deposition method is a magnetron sputtering method, the deposition process of the pure tin degradation film layer is as follows: mounting a magnesium substrate on an anode plate of a magnetron sputtering instrument; putting the tin target into a magnetron sputtering instrument to be used as a cathode; the vacuum degree is pumped to 10 ^-2 ～10 ^- ³ After Pa, introducing argon to stabilize the pressure in the magnetron sputtering instrument at 1-10 Pa; then preheating the magnesium substrate to 20-200 ℃; controlling the discharge voltage of 280V-350V, the current of 0.2A-0.6A, the deposition rate of 0.5-1.2 mu m/min and the deposition time of 10-20 min to obtain the pure tin degradation film.

7. The use of the biodegradable magnesium-based material containing the tin-pure degradable film layer according to claim 1, wherein the biodegradable magnesium-based material comprises: and taking the biodegradable magnesium-based material containing the pure tin degradable film layer as a biomedical metal implant material.