A core-shell gradient structure medical high-strength and low-elasticity titanium-zinc composite material, its preparation method and application

Abstract

The present invention discloses a core-shell gradient structure medical high-strength and low-elasticity titanium-zinc composite material, its preparation method and application, belonging to the technical field of composite materials. The titanium-zinc composite material has a core-shell structure and a gradient structure, with good compactness and excellent mechanical properties. The hardness of the titanium-zinc composite material is higher than that of pure titanium and much higher than that of pure zinc; it has high compressive strength and can meet the load-bearing requirements. In addition, the elastic modulus of the titanium-zinc composite material is low and close to that of human bone, which can overcome the stress shielding effect after implantation; the material has good wettability and can meet the cytotoxicity requirements of biological applications. The present invention also provides a preparation method of the titanium-zinc composite material, adopting a spark plasma sintering process, which is simple in process and convenient in production, and realizes the technical purpose of preparing a titanium-zinc composite material with a relatively uniform structure between titanium-zinc materials with a huge difference in melting points.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly to a core-shell gradient structure medical high-strength and low-elasticity titanium-zinc composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Titanium has good biocompatibility and corrosion resistance, is non-toxic and has no side effects on the human body. While having a low density and light weight, it also has excellent mechanical properties. Therefore, titanium is widely used in scenarios such as orthopedic implant materials, dental implants, artificial heart valves, etc., and is also an excellent raw material for medical surgical instruments. Titanium is a research focus in the field of biomedical metal materials. However, titanium still has some deficiencies as a medical material. Pure titanium does not have antibacterial properties, and bacterial infection during implantation or inflammation after implantation may lead to surgical failure. Pure titanium is a bio-inert material, and the implant cannot establish a close connection with human tissues, resulting in implant loosening. In addition, although the elastic modulus of pure titanium is lower than that of traditional implant materials such as stainless steel, it is still higher than that of human bone. Therefore, when implanted into the human body as a bone implant material, it bears too much load, and the bone cannot receive appropriate load for a long time, which will lead to osteoporosis, which is also the common "stress shielding" effect of metal implant materials. The alloying process is an effective way to reduce the elastic modulus of pure titanium.

[0003] Biodegradable metal materials can be gradually degraded in the biological environment of the human body, and the degradation products are non-toxic to organisms and even have a positive impact on the repair of biological tissues. Therefore, biodegradable metal materials have become a research hotspot in the field of medical materials in recent years. The common biodegradable metal materials are iron, magnesium, and zinc. The degradation rate of iron materials in the human body is too slow, and the difference between its elastic modulus and that of human bone is large, and the stress shielding effect is obvious when used as a substitute for the load-bearing part. Magnesium materials degrade too fast, and hydrogen is generated during the degradation process, which is not conducive to the establishment of a fusion relationship between the implant and human tissues. Zinc materials are essential trace elements for the human body, have a moderate degradation rate in the human body, and have antibacterial and osteogenic functions, and are an excellent choice for biodegradable metal implant materials. However, at the same time, the mechanical properties of zinc materials are poor and it is difficult to meet the mechanical property requirements of the load-bearing part.

[0004] In summary, organically combining the mechanical and corrosion-resistant properties of titanium and the biological characteristics of biodegradable zinc is a research direction of biomedical biodegradable metal materials with good prospects.

[0005] Due to the large melting point difference between titanium and zinc, it is difficult to prepare titanium-zinc composites by traditional casting and other processes. Preparing them by solid-state diffusion means such as sintering is a feasible idea. Spark Plasma Sintering (SPS) is a new type of rapid sintering technology that introduces a DC pulsed current into the sintering process. The punch and die act as carriers for the current while applying pressure to the material, enabling heating with the current while applying pressure, and can rapidly sinter powder materials into dense bulk materials at relatively low temperatures. Due to its unique characteristics, the SPS technology may open up a new path for the powder metallurgy preparation of titanium-zinc materials. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, a titanium-zinc composite material with high strength and low elastic modulus is provided. The titanium-zinc composite material has a core-shell structure formed by a titanium-zinc shell layer wrapping a titanium core; in the titanium-zinc shell layer, titanium and zinc elements form titanium-zinc compounds with different atomic ratios according to the increase in the distance from the titanium-zinc interface to the titanium core, and form a gradient structure in the titanium-zinc composite material.

[0007] In the second aspect of the present invention, a preparation method for a titanium-zinc composite material with simple process and convenient production is provided, including the following steps:

[0008] (1) Mix titanium powder and zinc powder evenly according to a ratio to obtain a mixed powder;

[0009] (2) Subject the mixed powder to spark plasma sintering treatment to make a titanium-zinc composite material.

[0010] In the present invention, the evenly mixed pure titanium and pure zinc powders undergo interatomic diffusion and reaction under the process conditions of high temperature and high pressure of spark plasma sintering (SPS). Since the diffusion rate of zinc atoms into titanium particles is much smaller than that of titanium atoms into zinc, ultimately, the pure titanium particles are gradually consumed, and around the pure titanium particles as the inner core, with the increase in the distance from the titanium-zinc interface, a gradient structure of titanium-zinc compounds with different atomic ratios is formed, and the pure titanium particles are wrapped in the form of a shell layer.

[0011] Preferably, in the step (1), the mass percentage of the zinc powder in the mixed powder ≤ 50%.

[0012] When the mass ratio of zinc in the powder is different, the shell layer also varies. When the mass fraction of zinc is less than 10%, the shell layer is a eutectic structure. When the mass fraction of zinc is greater than or equal to 10% and less than or equal to 50%, the composition of the shell layer may include components such as Ti9Zn, eutectic structure Ti 4.8 Zn, Ti2Zn, TiZn, TiZn2, etc.

[0013] This method has flexible process, and can flexibly regulate the components of titanium-zinc powder to meet different application requirements.

[0014] Preferably, the specific operation of step (2) is as follows: under vacuum conditions, the mixed powder is subjected to spark plasma sintering treatment to form a bulk material, and the bulk material is naturally cooled to room temperature to obtain a titanium-zinc composite material.

[0015] More preferably, the spark plasma sintering treatment is carried out in two stages, the first stage is the reaction stage, and the second stage is the sintering stage; in the reaction stage, pressure is first applied to the mixed powder, and then the temperature is raised to the reaction temperature and held at this temperature for a certain time; after the reaction stage is completed, it enters the sintering stage, the pressure applied to the mixed powder is first increased, and then the temperature is further raised to the sintering temperature and held at this temperature for a certain time.

[0016] Furthermore, in the reaction stage, the applied pressure is 10-20 MPa; the heating rate is 50-100 °C / min; the reaction temperature is 350-450 °C; the holding time is 10-20 min.

[0017] Furthermore, in the sintering stage, the applied pressure is 50-60 MPa; the heating rate is 50-100 °C / min; the sintering temperature is 700-800 °C; the holding time is 10-20 min.

[0018] In the third aspect of the present invention, there is provided an application of a titanium-zinc composite material of the first aspect of the present invention or a titanium-zinc composite material prepared by the preparation method of the second aspect of the present invention as a raw material in the preparation of metal implant materials.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The present invention provides a titanium-zinc composite material, which has a core-shell structure and a gradient structure, has good compactness, no obvious pores in the microstructure, and excellent mechanical properties. The hardness of the titanium-zinc composite material is higher than that of pure titanium and much higher than that of pure zinc; the compressive strength of the material is high and can meet the load-bearing requirements. In addition, the elastic modulus of the titanium-zinc composite material is low and close to that of human bone, which can overcome the stress shielding effect after implantation; the material has good wettability and can meet the cytotoxicity requirements of biological applications.

[0021] The present invention provides a preparation method of a titanium-zinc composite material. This method has a simple process and convenient production. By using the spark plasma sintering process and the diffusion principle, the technical purpose of preparing a titanium-zinc composite material with a relatively uniform structure between titanium and zinc materials with a huge difference in melting points is achieved.

[0022] The present invention also provides an application of the titanium-zinc composite material as a metal implant material, which provides an idea for achieving medical purposes by combining the mechanical properties of titanium and the biological characteristics of zinc, and has good medical prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Among them, (a)-(c) are scanning electron microscope (SEM) images of the titanium-zinc composite material of Example 1 at different magnifications; (d)-(f) are scanning electron microscope (SEM) images of the titanium-zinc composite material of Example 4 at different magnifications; (g)-(i) are scanning electron microscope (SEM) images of the titanium-zinc composite material of Example 8 at different magnifications; (j)-(l) are scanning electron microscope (SEM) images of the titanium-zinc composite material of Comparative Example 3 at different magnifications;

[0024] Figure 2 is the composition gradient diagram of X-ray energy spectrometer component analysis (EDS), and (a)-(d) respectively correspond to the composition gradients of the titanium-zinc composite materials of Example 1, Example 4, Example 8, and Comparative Example 3;

[0025] Figure 3 is the measured density and relative density measurement result diagram of the titanium-zinc composite materials of Examples 1-8 and Comparative Example 3;

[0026] Figure 4 is the hardness test result diagram of the titanium-zinc composite materials of Examples 1-8 and Comparative Example 3. Among them, the horizontal lines TA1 and pure Zn respectively represent the hardness values of pure titanium and pure zinc;

[0027] Figure 5 is the ultimate compressive strength, yield strength, and ultimate compression rate test result diagram of the titanium-zinc composite materials of Examples 1-8 and Comparative Example 3;

[0028] Figure 6 is the elastic modulus test result diagram of the titanium-zinc composite materials of Examples 1-8 and Comparative Example 3;

[0029] Figure 7 is the wettability test result diagram of different materials in Examples 1, 6, 8 and Comparative Examples 1 and 2;

[0030] Figure 8 is the cytotoxicity test result of different materials in Examples 1, 6, 8 and Comparative Examples 1 and 2. Among them, 1extraction, 1 / 2extraction, 1 / 4extraction, 1 / 8extraction respectively represent the material extract diluted to 1, 1 / 2, 1 / 4, 1 / 8, and the horizontal line is the cell activity standard. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0032] Example 1

[0033] Preparation method of titanium-zinc composite material:

[0034] (1) Mix pure zinc powder with a mass fraction of 20% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mixture uniform, obtaining a mixed powder;

[0035] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After the cavity is evacuated, carry out spark plasma sintering treatment in reaction stage and sintering stage in sequence; First, apply a pressure of 10 MPa to the mixed powder, and then heat it at a heating rate of 100 °C / min to 400 °C and hold for 15 min at this temperature; After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, and then continue to heat it at a heating rate of 100 °C / min to 700 °C and hold for 10 min at this temperature to form a bulk material; After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-20Zn according to the raw material ratio.

[0036] Example 2

[0037] Preparation method of titanium-zinc composite material:

[0038] (1) Mix pure zinc powder with a mass fraction of 3% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mixture uniform, obtaining a mixed powder;

[0039] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After the cavity is evacuated, carry out spark plasma sintering treatment in reaction stage and sintering stage in sequence; First, apply a pressure of 10 MPa to the mixed powder, and then heat it at a heating rate of 100 °C / min to 400 °C and hold for 15 min at this temperature; After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, and then continue to heat it at a heating rate of 100 °C / min to 700 °C and hold for 10 min at this temperature to form a bulk material; After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-3Zn according to the raw material ratio.

[0040] Example 3

[0041] Preparation method of titanium-zinc composite material:

[0042] (1) Mix pure zinc powder with a mass fraction of 5% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mix evenly, obtaining a mixed powder;

[0043] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage in sequence; First, apply a pressure of 10 MPa to the mixed powder, then heat it up to 400 °C at a heating rate of 100 °C / min and hold for 15 min at this temperature; After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to heat it up to 700 °C at a heating rate of 100 °C / min and hold for 10 min at this temperature to form a bulk material; After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-5Zn according to the raw material ratio.

[0044] Example 4

[0045] Preparation method of titanium-zinc composite material:

[0046] (1) Mix pure zinc powder with a mass fraction of 7% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mix evenly, obtaining a mixed powder;

[0047] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage in sequence; First, apply a pressure of 10 MPa to the mixed powder, then heat it up to 400 °C at a heating rate of 100 °C / min and hold for 15 min at this temperature; After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to heat it up to 700 °C at a heating rate of 100 °C / min and hold for 10 min at this temperature to form a bulk material; After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-7Zn according to the raw material ratio.

[0048] Example 5

[0049] Preparation method of titanium-zinc composite material:

[0050] (1) Mix pure zinc powder with a mass fraction of 10% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mix evenly, obtaining a mixed powder;

[0051] (2) Place the mixed powder in a mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage successively. First, apply a pressure of 10 MPa to the mixed powder, then increase the temperature to 400 °C at a heating rate of 100 °C / min and hold for 15 min at this temperature. After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to increase the temperature to 700 °C at a heating rate of 100 °C / min and hold for 10 min at this temperature to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-10Zn according to the raw material ratio.

[0052] Example 6

[0053] Preparation method of titanium-zinc composite material:

[0054] (1) Mix pure zinc powder with a mass fraction of 30% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder evenly mixed and obtain a mixed powder;

[0055] (2) Place the mixed powder in a mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage successively. First, apply a pressure of 10 MPa to the mixed powder, then increase the temperature to 400 °C at a heating rate of 100 °C / min and hold for 15 min at this temperature. After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to increase the temperature to 700 °C at a heating rate of 100 °C / min and hold for 10 min at this temperature to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-30Zn according to the raw material ratio.

[0056] Example 7

[0057] Preparation method of titanium-zinc composite material:

[0058] (1) Mix pure zinc powder with a mass fraction of 40% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder evenly mixed and obtain a mixed powder;

[0059] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in sequence through a reaction stage and a sintering stage. First, apply a pressure of 10 MPa to the mixed powder, then raise the temperature at a heating rate of 100 °C / min to 400 °C and hold for 15 min at this temperature. After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to raise the temperature at a heating rate of 100 °C / min to 700 °C and hold for 10 min at this temperature to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-40Zn according to the raw material ratio.

[0060] Example 8

[0061] Preparation method of titanium-zinc composite material:

[0062] (1) Mix pure zinc powder with a mass fraction of 50% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder evenly mixed and obtain a mixed powder;

[0063] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in sequence through a reaction stage and a sintering stage. First, apply a pressure of 10 MPa to the mixed powder, then raise the temperature at a heating rate of 100 °C / min to 400 °C and hold for 15 min at this temperature. After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to raise the temperature at a heating rate of 100 °C / min to 700 °C and hold for 10 min at this temperature to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish it to obtain a titanium-zinc composite material, denoted as Ti-50Zn according to the raw material ratio.

[0064] Example 9

[0065] Preparation method of titanium-zinc composite material:

[0066] (1) Mix pure zinc powder with a mass fraction of 20% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder evenly mixed and obtain a mixed powder;

[0067] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage in sequence. First, apply a pressure of 10 MPa to the mixed powder, then increase the temperature at a rate of 50 °C / min to 350 °C and hold at this temperature for 20 min. After the reaction stage is completed, enter the sintering stage. First, increase the pressure to 50 MPa, then continue to increase the temperature at a rate of 50 °C / min to 700 °C and hold at this temperature for 20 min to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish to obtain a titanium-zinc composite material.

[0068] Example 10

[0069] Preparation method of titanium-zinc composite material:

[0070] (1) Mix pure zinc powder with a mass fraction of 20% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder evenly mixed and obtain a mixed powder;

[0071] (2) Place the mixed powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment in reaction stage and sintering stage in sequence. First, apply a pressure of 20 MPa to the mixed powder, then increase the temperature at a rate of 100 °C / min to 450 °C and hold at this temperature for 10 min. After the reaction stage is completed, enter the sintering stage. Increase the pressure to 60 MPa, continue to increase the temperature at a rate of 100 °C / min to 800 °C and hold at this temperature for 10 min to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish to obtain a titanium-zinc composite material.

[0072] Comparative Example 1

[0073] Preparation method of pure titanium bulk material:

[0074] Place pure titanium powder in the mold of a spark plasma sintering furnace. After evacuating the cavity, perform spark plasma sintering treatment. Apply a pressure of 30 MPa to the pure titanium powder, then increase the temperature at a rate of 100 °C / min to 700 °C and hold at this temperature for 10 min to form a bulk material. After the bulk material is cooled to room temperature in the furnace, take it out, clean and polish to obtain a pure titanium bulk material.

[0075] Comparative Example 2

[0076] In this comparative example, commercially available pure zinc metal is used as the pure zinc bulk material for comparison in performance testing.

[0077] Comparative Example 3

[0078] Preparation method of titanium-zinc composite material:

[0079] (1) Mix pure zinc powder with a mass fraction of 50% and the remaining pure titanium powder, and then ball mill for 7 h under the conditions of a rotation rate of 250 r / min and a ball-to-powder ratio of 1:1 to make the powder mixture uniform, obtaining a mixed powder;

[0080] (2) Place the mixed powder in the mold of a spark plasma sintering furnace, evacuate the cavity and then conduct spark plasma sintering treatment; apply a pressure of 50 MPa to the mixed powder, then heat it at a heating rate of 100 °C / min to 350 °C and hold at this temperature for 25 min to form a bulk material; after the bulk material is cooled to room temperature in the furnace, take it out, clean, polish, and obtain a titanium-zinc composite material, denoted as *Ti-50Zn according to the raw material ratio.

[0081] Test Example 1

[0082] Test the various properties of the materials prepared in some examples and comparative examples of the present invention. Observe the microstructure of the materials under a scanning electron microscope (SEM); determine the composition of the materials by X-ray energy dispersive spectroscopy (EDS) for composition analysis; measure the density of the materials using a densitometer based on the principle of the Archimedes drainage method; test the hardness using a Vickers hardness tester; use a universal testing machine to test the compressive properties of cylinders with a sample specification of Φ4 mm * 8 mm, and the test contents include mechanical properties such as ultimate compressive strength, yield strength, ultimate compression ratio, and elastic modulus; test the wettability of the material surface to deionized water using a contact angle measuring instrument; test the cytotoxicity using the material extract; unless otherwise specified, generally use the general test parameters in the art.

[0083] Observe the microtopography of the materials of Example 1, Example 4, Example 8, and Comparative Example 3 through a scanning electron microscope (SEM), and analyze the composition gradient in combination with X-ray energy dispersive spectroscopy (EDS) for composition analysis. Figure 1 (a) - (l) respectively correspond to the microstructural organizations of 4 groups of material samples at different magnifications. From Figure 1 It can be seen that the above materials form a core-shell structure. Figure 2 (a) - (d) reflect the titanium and zinc atomic ratios of each layer of the materials of Example 1, Example 4, Example 8, and Comparative Example 3. From Figure 2 It can be seen that the composition corresponding to (a) of Ti-20Zn from the core to the shell is: Ti, Ti9Zn, Ti 4.8 Zn, Ti2Zn, TiZn, Ti7Zn3; the composition corresponding to (b) of Ti-7Zn from the core to the shell is: Ti, Ti 6.7 Zn; the composition corresponding to (c) of Ti-50Zn, from the core to the shell, is: Ti, Ti9Zn, Ti 4.8Zn, Ti2Zn, TiZn, TiZn2; (d) For *Ti-50Zn in Comparative Example 3, its shell is composed of TiZn3 and TiZn7. The EDS composition test results show that there is a gradient structure in the material composed of titanium-zinc compounds with different atomic ratios.

[0084] The actual density and relative density of the materials obtained in Examples 1-8 of the present invention and Comparative Example 3 were measured, and the results are shown in Figure 3 . The higher the relative density, the higher the sintering density; as Figure 3 shown, the density of the materials prepared by the process of the present invention is all above 99.4%, while the relative density of *Ti-50Zn in Comparative Example 3 is 97.8%, indicating a high sintering density.

[0085] The microhardness of the materials in Examples 1-8 and Comparative Example 3 was measured as shown in Figure 4 . Among them, the horizontal lines TA1 and pure Zn represent the hardness values of pure titanium and pure zinc respectively. It can be seen that the hardness of the materials prepared according to the present invention is higher than that of pure titanium and much higher than that of pure zinc, while the hardness of *Ti-50Zn in Comparative Example 3 is slightly lower than that of pure titanium.

[0086] The ultimate compressive strength, yield strength, and ultimate compression ratio of the materials in Examples 1-8 and Comparative Example 3 were measured respectively. As Figure 5 shown, the ultimate compressive strength of the materials prepared according to the present invention is all above 1200 MPa, while the ultimate compressive strength of *Ti-50Zn in Comparative Example 3 is 446 MPa.

[0087] Figure 6 Reflects the test results of the elastic modulus of the materials in Examples 1-8 and Comparative Example 3. As Figure 6 can be seen, the elastic modulus of all materials is between 25 and 35 GPa, while the elastic modulus of human bone is between 4 and 30 GPa. Therefore, the elastic modulus of the materials prepared by the present invention can achieve a good match with human bone.

[0088] The water wettability of the materials in Example 1, Example 6, Example 8 and Comparative Example 1, Comparative Example 2 was tested. When the contact angle <90°, it indicates that the wettability of the material is good. According to Figure 7 the test results, the materials of the examples have good wettability, which is better than that of pure zinc.

[0089] Finally, the cytotoxicity of the materials was detected. Figure 8Cytotoxicity test results of different materials in Example 1, 6, 8 and Comparative Example 1, 2. (a), (b), (c), (d) represent the material extracts diluted to 1, 1 / 2, 1 / 4, 1 / 8 respectively. The horizontal line is the cell activity standard. Higher than the standard line indicates that the cytotoxicity of the material meets the specified requirements. It can be seen that when directly culturing cells with the material extract, the cytotoxicity of the Ti-50Zn and pure zinc materials corresponding to Example 8 and Comparative Example 2 is relatively strong and does not meet the requirements, which may be related to the relatively high content of Zn element. When the material extract is diluted to less than half, excluding factors such as improper cell culture, it can be seen that all materials meet the cytotoxicity requirements at this time.

[0090] From the above test results, it can be seen that the titanium-zinc composite material prepared by the present invention has a core-shell structure and a gradient structure, with good compactness, no obvious pores in the microstructure, and excellent mechanical properties. The hardness of the titanium-zinc composite material is higher than that of pure titanium and much higher than that of pure zinc; the compressive strength of the material is high and can meet the load-bearing requirements. In addition, the elastic modulus of the titanium-zinc composite material is relatively low, close to that of human bone, which can overcome the stress shielding effect after implantation; the material has good wettability and can meet the cytotoxicity requirements for biological applications. The present invention provides an idea for achieving medical purposes by combining the mechanical properties of titanium and the biological characteristics of zinc, and has good medical prospects when used as a metal implant material.

[0091] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A titanium-zinc composite material, characterized in that: The titanium-zinc composite material has a core-shell structure formed by a titanium-zinc shell layer wrapping a titanium core; in the titanium-zinc shell layer, titanium and zinc elements form titanium-zinc compounds with different atomic ratios according to the increase in the distance between the titanium-zinc interface and the titanium core, and form a gradient structure in the titanium-zinc composite material; The titanium-zinc composite material is prepared by the following preparation method, including the following steps: (1) Mix titanium powder and zinc powder evenly according to a ratio to obtain a mixed powder; The mass percentage of zinc powder in the mixed powder ≤ 50%; (2) Under vacuum conditions, the mixed powder is subjected to spark plasma sintering treatment to form a bulk material, and the bulk material is naturally cooled to room temperature to obtain a titanium-zinc composite material; The spark plasma sintering treatment is carried out in two stages. The first stage is the reaction stage, and the second stage is the sintering stage; in the reaction stage, first apply pressure to the mixed powder, and then raise the temperature to the reaction temperature and keep it at this temperature for a certain time; after the reaction stage is completed, enter the sintering stage, first increase the pressure on the mixed powder, and then further raise the temperature to the sintering temperature and keep it at this temperature for a certain time; In the reaction stage, the applied pressure is 10-20 MPa; the heating rate is 50-100 °C / min; the reaction temperature is 350-450 °C; the holding time is 10-20 min; In the sintering stage, the applied pressure is 50-60 MPa; the heating rate is 50-100 °C / min; the sintering temperature is 700-800 °C; the holding time is 10-20 min.

2. A method for preparing a titanium-zinc composite material as described in claim 1, characterized in that, Including the following steps: (1) Mix titanium powder and zinc powder evenly according to a ratio to obtain a mixed powder; The mass percentage of zinc powder in the mixed powder ≤ 50%; (2) Under vacuum conditions, the mixed powder is subjected to spark plasma sintering treatment to form a bulk material, and the bulk material is naturally cooled to room temperature to obtain a titanium-zinc composite material; The obtained titanium-zinc composite material has a core-shell structure formed by a titanium-zinc shell layer wrapping a titanium core; in the titanium-zinc shell layer, titanium and zinc elements form titanium-zinc compounds with different atomic ratios according to the increase in the distance between the titanium-zinc interface and the titanium core, and form a gradient structure in the titanium-zinc composite material; The spark plasma sintering treatment is carried out in two stages. The first stage is the reaction stage, and the second stage is the sintering stage; in the reaction stage, first apply pressure to the mixed powder, and then raise the temperature to the reaction temperature and keep it at this temperature for a certain time; after the reaction stage is completed, enter the sintering stage, first increase the pressure on the mixed powder, and then further raise the temperature to the sintering temperature and keep it at this temperature for a certain time; In the reaction stage, the applied pressure is 10-20 MPa; the heating rate is 50-100 °C / min; the reaction temperature is 350-450 °C; the holding time is 10-20 min; In the sintering stage, the applied pressure is 50-60 MPa; the heating rate is 50-100 °C / min; the sintering temperature is 700-800 °C; the holding time is 10-20 min.

3. Application of a titanium-zinc composite material prepared according to the titanium-zinc composite material described in claim 1 or the preparation method described in claim 2 as a raw material in the preparation of a metal implant material.

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