A zinc-based composite material and a preparation method and application thereof

Abstract

This invention belongs to the field of metal matrix composite material preparation technology, specifically relating to a zinc-based composite material, its preparation method, and its application, addressing the problems of insufficient mechanical properties and difficulty in uniformly dispersing nanoparticles in pure zinc materials. The zinc-based composite material comprises a zinc matrix and fine nano-ceramic particles. The nano-ceramic particles have a particle size of 50-99 nm and a volume fraction of 0.5-2 vol%, uniformly dispersed within the zinc matrix. The preparation method involves an in-situ exchange reaction to transfer coarse nano-ceramic particles from an aluminum carrier to the zinc matrix, dispersing and refining them to obtain a zinc-based composite material with fine nano-ceramic particles. This invention solves the technical problem in existing technologies where high-melting-point ceramic materials are prone to floating, agglomeration, or interfacial separation, resulting in difficulty in precisely controlling the particle size below 100 nm. It achieves a uniform distribution of the ceramic reinforcing phase below 100 nm, thereby improving the creep and mechanical properties of the zinc-based composite material.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite material preparation technology, specifically to an in-situ nano-reinforced zinc matrix composite material, its preparation method and application, and is particularly applicable to the field of biodegradable biomedical implant materials. Background Technology

[0002] Zinc and zinc-based alloys, as a class of biodegradable metallic materials, have shown broad application prospects in biomedical fields such as orthopedic implants and cardiovascular stents due to their suitable degradation rate, good biocompatibility, and mechanical properties similar to human bone tissue. The degradation products of pure zinc materials can be metabolized and absorbed by the human body, avoiding the need for a second surgery to remove traditional permanent implant materials, and therefore have attracted widespread attention from the medical and materials science communities.

[0003] However, existing pure zinc materials generally suffer from insufficient mechanical properties in practical applications. Pure zinc has low tensile strength and poor creep resistance at human body temperature (approximately 37°C), making it prone to plastic deformation under long-term physiological loads. This makes it difficult to meet the long-term mechanical stability requirements of load-bearing implants (such as orthopedic internal fixation devices). To improve the mechanical properties of pure zinc materials, researchers have explored various strengthening methods, among which introducing nanoscale reinforcing phases into the zinc matrix is ​​an effective technical approach.

[0004] Chinese patent CN109500396A discloses an intracrystalline-intercrystalline composite reinforced bio-zinc alloy and its preparation method. This method uses graphene to encapsulate nano-silicon carbide particles, and prepares the zinc-based composite material through batch cryogenic ball milling and selective laser melting. This method achieves the distribution of nano-ceramic particles in the zinc matrix, improving the mechanical properties of the material. However, this technical solution requires graphene as the encapsulation material, the process is complex, and it relies on expensive equipment such as powder metallurgy and laser melting, resulting in high manufacturing costs and making large-scale industrial production difficult. Furthermore, this solution does not clearly define the particle size range of the nanoparticles in the final product, and the precision of particle size control needs to be improved.

[0005] On the other hand, the method of directly adding nano-ceramic particles to zinc melt also faces many technical challenges. Due to the poor wettability between high-melting-point ceramic materials (such as titanium carbide) and zinc melt, nanoparticles are prone to floating, agglomeration, or interfacial separation in zinc melt, making it difficult to form a stable and uniform dispersed distribution structure in the zinc matrix. Although traditional physical dispersion methods such as mechanical stirring or ultrasonic treatment can improve particle distribution to some extent, they still cannot fundamentally solve the problem of nanoparticle agglomeration, and the ability to precisely control the particle size is limited. Especially when it is necessary to control the nanoparticle size below 100 nanometers, existing technologies often fail to achieve a stable preparation process.

[0006] Furthermore, existing patent protections for nano-reinforced zinc-based composites primarily focus on nanoparticles with diameters greater than 100 nanometers. Systematic research and patent strategies for preparing zinc-based materials reinforced with nanoparticles smaller than 100 nanometers are lacking. However, studies have shown that further reducing the nanoparticle size to below 100 nanometers can significantly improve the strengthening effect of the material, particularly demonstrating a greater advantage in improving creep resistance.

[0007] Therefore, a new technical solution needs to be developed to achieve uniform dispersion of nano-ceramic particles in a pure zinc matrix, especially to precisely control the average particle size of the nanoparticles to below 100 nm, while simplifying the preparation process and reducing production costs, so as to meet the actual demand of biodegradable biomedical implant materials for high-performance nano-reinforced zinc-based composite materials. Summary of the Invention

[0008] This invention provides a zinc-based composite material, its preparation method, and its application, to solve the technical problem in the prior art where the particle size of high-melting-point ceramic materials is difficult to precisely control below 100 nm due to easy floating, agglomeration, or interface separation. It achieves a uniform distribution of ceramic reinforcing phase below 100 nm, thereby improving the long-term mechanical stability of load-bearing biological implants (such as orthopedic internal fixation devices).

[0009] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a zinc-based composite material comprising a zinc matrix and nano-ceramic fine particles dispersed in the zinc matrix, wherein the average particle size of the nano-ceramic fine particles is 50-99 nm; the volume fraction of the nano-ceramic fine particles in the zinc matrix is ​​0.5-2.5 vol%, and the nano-ceramic fine particles are uniformly dispersed in the zinc matrix.

[0010] In one specific embodiment of the present invention, the nano-ceramic fine particles are titanium carbide or titanium boride.

[0011] In one specific embodiment of the present invention, the nano-ceramic fine particles are titanium carbide.

[0012] In one specific embodiment of the present invention, the average particle size of the nano-ceramic fine particles is 60-90 nm.

[0013] In one specific embodiment of the present invention, the steady-state creep rate of the zinc-based composite material at 310K temperature and 50MPa load is no greater than .

[0014] The present invention also provides a method for preparing the above-mentioned zinc-based composite material, including the steps of providing an aluminum support containing coarse nano-ceramic particles and heating the aluminum support into a melt or a semi-melt under an inert atmosphere; It also includes the following steps: Provides a salt mixture containing zinc chloride; The salt mixture is added to the melt or semi-melt, and the coarse nano-ceramic particles are transferred to the zinc matrix generated by the reaction through the in-situ exchange reaction between the aluminum carrier and the zinc chloride. Mechanical stirring is performed during the in-situ reaction process to promote the refinement and dispersion of the coarse nano-ceramic particles. After the in-situ reaction is completed, the liquid is cooled and subjected to hot rolling plastic deformation treatment and homogenization heat treatment to obtain zinc-based composite material.

[0015] In one specific embodiment of the present invention, the aluminum carrier is elemental aluminum; the volume fraction of the nano-ceramic coarse particles in the elemental aluminum is 1-3 vol.

[0016] In one specific embodiment of the present invention, the temperature of the in-situ substitution reaction is 650-700°C.

[0017] In one specific embodiment of the present invention, the temperature of the in-situ substitution reaction is 670°C.

[0018] In one specific embodiment of the present invention, the salt mixture further includes sodium chloride and potassium chloride; wherein the mass ratio of zinc chloride, sodium chloride and potassium chloride is 230:(97-117):(120-150).

[0019] In one specific embodiment of the present invention, the molar ratio between zinc in the chloride salt mixture and aluminum in the aluminum carrier is 2.7-3.3:2.

[0020] In one specific embodiment of the present invention, the mechanical stirring speed is 20-50 RPM and the stirring time is 15-30 minutes.

[0021] In one specific embodiment of the present invention, during the in-situ displacement reaction process, the stirring blades of the mechanical stirring are controlled to be above the surface of the melt or semi-melt.

[0022] In one specific embodiment of the present invention, it is 0.5-2 cm above the surface of the melt.

[0023] In one specific embodiment of the present invention, before the in-situ exchange reaction, 10 wt% of a salt mixture is added to carry out the in-situ exchange reaction; then, under continuous stirring, the remaining salt mixture is gradually added over 20 minutes; finally, stirring is continued until the in-situ exchange reaction is completed.

[0024] In one specific embodiment of the present invention, the inert atmosphere is an argon atmosphere.

[0025] In one specific embodiment of the present invention, the parameters of the hot rolling plastic deformation treatment are controlled as follows: temperature 200-300℃, deformation amount 1:10-1:100.

[0026] In one specific embodiment of the present invention, the homogenization heat treatment temperature is 200-300°C, and the holding time is 1-3 hours. After the heat treatment holding time is completed, the material is allowed to cool naturally to room temperature. This eliminates the stress in the zinc-based composite material and promotes further uniform dispersion of the nano-ceramic particles.

[0027] The above-mentioned zinc-based composite material is used in the preparation of biodegradable biomedical implant materials.

[0028] Because of its excellent mechanical properties (especially creep resistance), good biocompatibility, and suitable degradation rate, the zinc-based composite material of this invention is particularly suitable for the preparation of load-bearing biodegradable implants such as orthopedic internal fixation devices (e.g., bone screws, bone plates) and cardiovascular stents. While the material gradually degrades within the human body, its mechanical properties are maintained for a sufficiently long time to support tissue healing. The degradation products can be metabolized and absorbed by the body, avoiding the need for a second surgery to remove traditional permanent implant materials.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention achieves precise control of the particle size of nano-ceramic particles, keeping the particle size within the range of 50-99 nm, thus filling a technological gap. Through an in-situ displacement reaction mechanism, particles of 100-500 nm in the aluminum carrier are dispersed and refined during the transfer to the zinc matrix, ultimately forming a dispersed distribution structure of nanoparticles with an average particle size of less than 100 nm. This particle size refinement mechanism helps to overcome the problem of nanoparticle agglomeration and particle size increase.

[0030] (2) This invention achieves uniform dispersion of nano-ceramic particles in a zinc matrix, effectively avoiding problems such as nanoparticle agglomeration, segregation, and insufficient interfacial bonding caused by traditional direct addition methods. By employing an in-situ displacement reaction mechanism, nanoparticles are simultaneously dispersed during the solidification process of the zinc matrix, forming a stable nanoparticle-metal interface structure, achieving a dual uniform distribution within and between grains, thus ensuring the long-term mechanical stability of the material.

[0031] (3) This invention significantly improves the creep resistance of the material. Under human body temperature (310K) and 50MPa load conditions, the creep rate is reduced from that of pure zinc. Reduce to The creep resistance is increased by more than an order of magnitude, up to approximately 40 times, meeting the long-term mechanical stability requirements of biodegradable load-bearing implants. Simultaneously, the material achieves improved strength and hardness while maintaining good plasticity, resulting in a significant improvement in overall mechanical properties.

[0032] (4) This invention simplifies the preparation process of zinc-based composite materials and reduces production costs. Compared with the complex processes of graphene encapsulation + ball milling + laser melting used in the prior art, this invention uses a melt method combined with molten salt medium and mechanical stirring, eliminating the need for auxiliary means such as graphene encapsulation. The process is simple, requires less equipment investment, and is easy to realize large-scale industrial production. At the same time, this method has lower requirements for raw materials and can use commercially available aluminum-based carriers, further reducing manufacturing costs. It eliminates the need for mechanically grinding nano-ceramic particles to below 100nm, thus reducing the manufacturing cost of nano-ceramic particles.

[0033] (5) The present invention expands the types of nano-ceramic particles in zinc-based composite materials, and is applicable to the transfer and refinement of various nano-ceramic particles. The application prospects of zinc-based composite materials are broad. Attached Figure Description

[0034] Figure 1 The images show the SEM morphology of Zn-TiC in Example 1 of this invention; where a is the SEM morphology of the as-cast Zn-TiC alloy at 100 μm, b is the SEM morphology of the as-cast Zn-TiC alloy at 20 μm, c is the SEM morphology of Zn-TiC after hot rolling and plastic deformation treatment at 10 μm, and d is the SEM morphology of Zn-TiC after hot rolling and plastic deformation treatment at 2 μm. Figure 2 This is a SEM image of the Zn-TiC product after homogenization heat treatment in Example 1 of the present invention; Figure 3 Photographs of anti-creep performance tests provided for specific embodiments of the present invention; Figure 4 A schematic diagram illustrating the creep resistance test principle for a specific embodiment of the present invention. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the technical terms used in the following embodiments are defined as follows: nano-ceramic particles refer to ceramic material particles with a particle size at the nanoscale (1-999 nm), including but not limited to carbides such as titanium carbide (TiC) and titanium boride (TiB2); in-situ displacement reaction refers to the process in which coarse nano-ceramic particles are transferred in situ from the aluminum carrier to the zinc matrix through a chemical displacement reaction between aluminum and zinc chloride during the formation of the zinc matrix; uniform dispersion distribution refers to the three-dimensional spatial uniform dispersion of fine nano-ceramic particles in the zinc matrix, with uniform particle spacing and no obvious agglomeration or segregation. Example

[0036] This embodiment provides a method for preparing a titanium carbide (TiC) reinforced pure zinc composite material, including the following steps: 1. Take a piece of aluminum-TiC master alloy with a mass of 30g and a TiC particle volume fraction of 2vol%.

[0037] 2. Accurately weigh the following raw materials: 107g sodium chloride (NaCl), 135g potassium chloride (KCl), and 230g zinc chloride (ZnCl2); mix the three salts thoroughly to obtain a salt mixture; 3. Place the aluminum-TiC master alloy into a graphite crucible, heat it to 670°C under an argon protective atmosphere and stir mechanically until the aluminum-TiC master alloy is completely melted to obtain a melt. 4. Add 50g of salt mixture to the melt, and keep the position of the stirring blade of the mechanical stirrer above the surface of the melt metal, about 1cm away from the surface of the melt metal. 5. Turn off the argon gas and, under continuous stirring at 30 RPM, gradually add the remaining salt mixture to the melt over 20 minutes. 6. After the salt mixture is added, continue mechanical stirring for 5 minutes until the reaction is complete at the original position; 7. Cast the molten material into a container, cool it, and then hot-roll it for plastic deformation treatment. The parameters for hot-rolling plastic deformation treatment are controlled as follows: temperature 250℃, deformation ratio 1:55.

[0038] 8. The room temperature, strip-shaped zinc-based composite material obtained by hot rolling plastic deformation treatment is homogenized at 250℃ for 2 hours to obtain titanium carbide reinforced pure zinc composite material, denoted as Zn-TiC. Example

[0039] In this embodiment, Zn-TiB2 composite material was prepared using the same method as in Example 1. Example

[0040] The Zn-TiC composite material prepared in this embodiment differs from that in Example 1 in that the volume fraction of TiC particles in the aluminum-TiC master alloy is 1 vol.

[0041] Characterization of the above composite materials: 1. Scanning electron microscope (SEM) morphology like Figure 1As shown, scanning electron microscopy (SEM) observations indicate that in the Zn-TiC of Example 1, TiC nanoparticles exhibit a uniform distribution within the zinc matrix, without significant sintering. The brighter granular phase in the image represents the TiC nanoparticles, while the darker background area represents the zinc matrix. Figure 1 As can be seen in a and b, in the Zn-TiC as-cast alloy sample, while the nanoparticles maintain a uniform distribution overall, diverse quasi-cluster structures can be observed locally. This phenomenon can be attributed to the good wettability between titanium carbide (TiC) and zinc, which promotes the spontaneous dispersion of TiC nanoparticles into the zinc matrix with the help of aluminum during the high-temperature melting stage.

[0042] Depend on Figure 1 As can be seen from figures c and d, after the process is completed, the distribution state of the TiC nanoparticles undergoes a significant change, exhibiting a more uniform and significantly improved dispersion throughout the material system. Therefore, it can be determined that the plastic deformation process helps to further promote the effective and uniform dispersion of nanoparticles in the material.

[0043] From the appendix Figure 2 It is evident that after homogenization heat treatment, the TiC particles in Zn-TiC exhibit better uniform dispersion. This result indicates that in-situ displacement can provide a basis for the uniform dispersion of TiC particles, and further thermoplastic and homogenization heat treatment can improve the dispersion of TiC particles in the Zn matrix and prevent agglomeration.

[0044] 2. Creep resistance As attached Figure 3-4 As shown, based on the creep resistance test method in ASTM E139, the creep rates of pure zinc and the above-mentioned Zn-TiC were tested at 310K and 20MPa, 35MPa and 50MPa.

[0045]

[0046] Based on the creep resistance test method in ASTM E139, the creep rates of pure zinc and Zn-TiC in Example 1 were tested at 50 MPa and 297.15 K, 310.15 K and 323.15 K. The results are shown in Table 2 below.

[0047] Table 2. Creep rates of pure zinc and Zn-TiC from Example 1 at 50 MPa and 297.15 K, 310.15 K, and 323.15 K.

[0048]

[0049] In summary: (1) The embodiments of the present invention achieve precise control of the particle size of nano-ceramic particles, controlling the particle size within the range of 50-99 nm, filling a technological gap. Through the in-situ displacement reaction mechanism, particles of 100-500 nm in the aluminum carrier are dispersed and refined during the transfer to the zinc matrix, ultimately forming a dispersed distribution structure of nanoparticles with an average particle size of less than 100 nm. This particle size refinement mechanism helps to overcome the problem of nanoparticle agglomeration and particle size increase.

[0050] (2) The embodiments of the present invention achieve uniform dispersion of nano-ceramic particles in a zinc matrix, effectively avoiding problems such as nanoparticle agglomeration, segregation, and insufficient interfacial bonding caused by traditional direct addition methods. By adopting an in-situ displacement reaction mechanism, nanoparticles are simultaneously dispersed during the solidification process of the zinc matrix, forming a stable nanoparticle-metal interface structure, achieving a dual uniform distribution within and between grains, and providing a guarantee for the long-term mechanical stability of the material.

[0051] (3) The embodiments of the present invention significantly improve the creep resistance of the material. Under human body temperature (310K) and 50MPa load conditions, the creep rate is reduced from that of pure zinc. Reduce to The creep resistance is increased by more than an order of magnitude, up to approximately 40 times, meeting the long-term mechanical stability requirements of biodegradable load-bearing implants. Simultaneously, the material achieves improved strength and hardness while maintaining good plasticity, resulting in a significant improvement in overall mechanical properties.

[0052] (4) The embodiments of the present invention simplify the preparation process of zinc-based composite materials and reduce production costs. Compared with the complex processes of graphene encapsulation + ball milling + laser melting used in the prior art, the embodiments of the present invention use a melt method combined with molten salt medium and mechanical stirring, which does not require auxiliary means such as graphene encapsulation. The process is simple, requires less equipment investment, and is easy to realize large-scale industrial production. At the same time, the method has lower requirements for raw materials and can use commercially available aluminum-based carriers, further reducing manufacturing costs. It eliminates the need for mechanical grinding of nano-ceramic particles to below 100nm, thus reducing the manufacturing cost of nano-ceramic particles.

[0053] (5) The present invention expands the types of nano-ceramic particles in zinc-based composite materials, and is applicable to the transfer and refinement of various nano-ceramic particles. Zinc-based composite materials have broad application prospects.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A zinc-based composite material, comprising a zinc matrix and nano-ceramic fine particles dispersed in the zinc matrix, characterized in that: The average particle size of the nano-ceramic fine particles is 50-99 nm; the volume fraction of the nano-ceramic fine particles in the zinc matrix is ​​0.5-2.5 vol%, and the nano-ceramic fine particles are uniformly dispersed in the zinc matrix.

2. The zinc-based composite material according to claim 1, characterized in that: The nano-ceramic fine particles are titanium carbide or titanium boride.

3. The zinc-based composite material according to claim 1, characterized in that: The average particle size of the nano-ceramic fine particles is 60-90 nm.

4. The zinc-based composite material according to claim 1, characterized in that: The steady-state creep rate of the zinc-based composite material at 310K temperature and 50MPa load is no greater than […]. .

5. A method for preparing the zinc-based composite material according to any one of claims 1-4, comprising the steps of providing an aluminum support containing coarse nano-ceramic particles, and heating the aluminum support into a melt or a semi-melt under an inert atmosphere; Its features are, It also includes the following steps: Provides a salt mixture containing zinc chloride; The salt mixture is added to a melt or semi-melt, and the coarse nano-ceramic particles are transferred to the zinc matrix generated by the reaction through an in-situ exchange reaction between the aluminum support and the zinc chloride. Mechanical stirring is performed during the in-situ exchange reaction process to promote the refinement of the coarse nano-ceramic particles into fine nano-ceramic particles and their dispersion. After the reaction is completed in situ, the solution is cooled and then subjected to hot rolling plastic deformation and homogenization heat treatment to obtain a zinc-based composite material.

6. The preparation method according to claim 5, characterized in that: The aluminum carrier is elemental aluminum; the volume fraction of the nano-ceramic coarse particles in the elemental aluminum is 1-3 vol.

7. The preparation method according to claim 5, characterized in that: The in-situ exchange reaction is carried out at a temperature of 650-700℃; preferably, the temperature is 670℃.

8. The preparation method according to claim 5, characterized in that: The salt mixture further includes sodium chloride and potassium chloride; wherein the mass ratio of zinc chloride, sodium chloride and potassium chloride is 230:(97-117):(120-150).

9. The preparation method according to claim 5, characterized in that: The molar ratio between zinc in the chloride salt mixture and aluminum in the aluminum carrier is 2.7-3.3:

2.

10. The preparation method according to claim 5, characterized in that: The mechanical stirring speed is 20-50 RPM, and the stirring time is 15-30 minutes.

11. The preparation method according to claim 5, characterized in that: During the in-situ reaction, the stirring blades of the mechanical stirring are positioned above the surface of the melt; preferably, they are 0.5-2 cm above the surface of the melt.

12. The preparation method according to claim 5, characterized in that: In the in-situ exchange reaction, 10 wt% of the salt mixture is added first; then, the remaining salt mixture is gradually added over 20 minutes with continuous stirring; finally, stirring continues until the in-situ exchange reaction is complete.

13. The preparation method according to claim 5, characterized in that: The inert atmosphere is an argon atmosphere.

14. The preparation method according to claim 5, characterized in that: The parameters for the hot rolling plastic deformation treatment are controlled as follows: temperature 200-300℃, deformation amount 1:10-1:

100.

15. The preparation method according to claim 5, characterized in that: The homogenization heat treatment temperature is 200-300℃, and the holding time is 1-3 hours.

16. The use of the zinc-based composite material according to any one of claims 1-4 or the zinc-based composite material prepared by the preparation method according to any one of claims 5-15 in the preparation of biodegradable biomedical implant materials.

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