Low-modulus titanium alloy with surface wear-reducing / antibacterial composite microstructure and method of manufacture

Abstract

The application discloses a low-modulus titanium alloy with surface wear-reducing / antibacterial composite function microstructure and a preparation method thereof. The titanium alloy comprises a low-modulus Ti-Mo alloy base and Ti5Si3, Ti3SiC2 and Ti3(Cu, Si)C2 micro-porous structures loaded on the surface. The preparation method comprises the following steps: placing MoSi2 powder after corrosion in a CuCl2 solution to form copper ion loaded MoSi2 powder; mixing the powder with medical titanium alloy powder by ball milling, and forming a low-modulus Ti-Mo alloy under the action of high-temperature sintering; and making carbon decomposed from methane gas react with Ti, Si and Cu in the low-modulus Ti-Mo alloy base in situ by a femtosecond laser beam to form Ti5Si3, Ti3SiC2 and Ti3(Cu, Si)C2 micro-porous structures. The process can not only reduce the elastic modulus of the titanium alloy and eliminate the "stress shielding" effect, but also significantly improve the wear resistance and antibacterial property of the titanium alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of medical multifunctional titanium alloy and its preparation method, especially to a kind of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure and preparation method. BACKGROUND

[0002] Titanium and its alloys as a kind of medical metal material, because it has higher hardness, tensile strength, bending strength and yield strength, and toughness, processing performance and good biocompatibility, has become the first choice material of human hard tissue implant, often used in artificial joints, bone plate and dental implant etc..But titanium alloy in the complex physiological environment of human body and human bone friction process will produce a large number of grinding dust, the accumulation of grinding dust will cause abnormal infection and allergy of surrounding tissue, also can cause bone resorption;At the same time, titanium is a kind of biological inert material, after implanting into human body, titanium surface is easy to adhere to bacteria, which can proliferate rapidly, eventually form biofilm, cause inflammation of host, even turn into chronic inflammation, delay healing, and may endanger the life of patient. On the other hand, the elastic modulus of pure titanium is higher than 100 GPa (the elastic modulus of human natural bone is about 30 GPa), so it is easy to cause a certain degree of "stress shielding" effect after implantation, causing aseptic loosening. Therefore, the above-mentioned functional deficiencies have become the main technical problems faced by current medical titanium alloy. In order to solve the above problems, at present, physical / chemical surface modification methods such as magnetron sputtering, polymer grafting and laser texturing are often used to modify the surface of medical titanium alloy. By changing the microstructure or chemical composition of the surface of titanium alloy implant, the surface functional properties of titanium alloy implant can be improved, so as to improve the wear resistance, antibacterial property and biological activity of medical titanium alloy. The above method improves the biological functional properties of medical titanium alloy to some extent, but also has new technical problems, such as weak adhesion between coating and titanium alloy substrate, which causes premature failure of coating, and single function of surface microstructure, which affects the service performance and life of medical titanium alloy. SUMMARY

[0003] The present application aims to provide a kind of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure;Another object of the present application is to provide a kind of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure.

[0004] Technical scheme: the low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure provided by the present application comprises a low modulus Ti-Mo alloy substrate, and a micro-porous structure of Ti5Si3, Ti3SiC2 and antibacterial Ti3(Cu, Si)C2 with wear reduction function loaded on the surface, and the elastic modulus of the low modulus titanium alloy is 20-25 Gpa.

[0005] Further, the micro-porous structure of the Ti5Si3, Ti3SiC2 and antibacterial function Ti3(Cu, Si)C2 of the low-modulus titanium alloy is formed by in-situ reaction of carbon decomposed from methane gas and Ti, Si and Cu in the low-modulus titanium alloy matrix.

[0006] The method for preparing the low-modulus titanium alloy with surface anti-friction / antibacterial composite function microstructure comprises the following steps:

[0007] (1) MoSi2 powder is corroded by a hydrofluoric acid aqueous solution, and then placed in a CuCl2 aqueous solution for standing and drying to obtain copper ion loaded MoSi2 powder;

[0008] (2) The copper ion loaded MoSi2 powder is mixed with medical titanium alloy powder by ball milling to obtain uniformly mixed medical titanium alloy composite powder;

[0009] (3) The medical titanium alloy composite powder is sintered at high temperature to promote dissolution and diffusion of the MoSi2 powder, and form a low-modulus Ti-Mo alloy;

[0010] (4) In a mixed protective atmosphere of methane and argon, a femtosecond laser beam is used to scan the surface of the low-modulus Ti-Mo alloy to promote in-situ reaction of carbon decomposed from methane gas and Ti, Si and Cu in the low-modulus Ti-Mo alloy matrix to form a micro-porous structure of Ti5Si3, Ti3SiC2 and antibacterial function Ti3(Cu, Si)C2 with anti-friction function.

[0011] Further, the concentration of the CuCl2 aqueous solution in step (1) is 0.1-0.3 mol / L, the drying environment is an argon atmosphere at a temperature of 100-150℃, and the volume fraction of the hydrofluoric acid aqueous solution is 5%.

[0012] Further, the mass ratio of the MoSi2 powder to the medical titanium alloy powder in step (2) is 1:40-1:60.

[0013] Further, the sintering temperature in step (3) is 1200-1500℃.

[0014] Further, the volume ratio of methane to argon in step (4) is 1:40-1:80.

[0015] Further, the power of the femtosecond laser beam in step (4) is 0.3-1 W.

[0016] Invention principle: The present application is around the medical titanium alloy multifunctional demand, aiming at the current medical implant titanium alloy elastic modulus and human adaptation, wear resistance and antibacterial deficiency, based on the principle of material design and the performance characteristics of carbon silicide ceramic, using hydrofluoric acid to corrode micro pits on the surface of MoSi2 powder, and then static in CuCl2 aqueous solution, which can promote copper ions to be adsorbed on the surface of micro pits with large specific surface area; Then mixed with medical titanium alloy powder and high temperature sintering, MoSi2 powder dissolves and diffuses, promotes Mo solid solution in titanium lattice, forms beta type Ti-Mo alloy with low elastic modulus, on this basis, under the action of femtosecond laser beam, carbon source is obtained by promoting the decomposition of methane gas at high temperature, and Ti, Si and carbon are induced to react in situ to form Ti3SiC2 microporous structure with wear reduction function, which gives titanium alloy wear reduction function; At the same time, the high temperature action of laser beam promotes the replacement of silicon atoms in Ti3SiC2 by copper atoms, forms antibacterial function Ti3(Cu,Si)C2 phase, and silicon atoms and titanium atoms react at high temperature to form Ti5Si3 ceramic phase, which effectively enhances the antibacterial function of microstructure, and forms low modulus titanium alloy with wear reduction / antibacterial composite function microstructure.

[0017] Beneficial effects: Compared with the prior art, the present application has the following obvious advantages:

[0018] (1) The method uses femtosecond laser beam to induce Ti, Si and carbon to react in situ to form Ti3SiC2 microporous structure with wear reduction function, which gives titanium alloy wear reduction function, and the porous structure can induce the rapid growth of bone tissue;

[0019] (2) Based on the crystal structure characteristics of Ti3SiC2 and the antibacterial property of copper, the high temperature action of femtosecond laser beam is used to induce Cu atoms to replace Si atoms in Ti3SiC2 lattice, form Ti3(Cu,Si)C2 solid solution phase and Ti5Si3 ceramic phase, give Ti3SiC2 microporous structure antibacterial property and porous structure wear resistance, which can effectively improve the antibacterial property and wear resistance of medical titanium alloy. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Figure 1 is the microstructure diagram of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure prepared in example 1, wherein 1 is Ti3SiC2 phase, 2 is Ti5Si3 phase, and 3 is Ti3(Cu,Si)C2 phase;

[0021] Figure 2 Figure 2 is the wear rate of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure prepared in examples 1-4;

[0022] Figure 3 Figure 3 is the elastic modulus of low modulus titanium alloy with surface wear reduction / antibacterial composite function microstructure prepared in examples 1-4. DETAILED DESCRIPTION

[0023] The technical solutions of the present application are further described below with reference to the accompanying drawings.

[0024] Example 1

[0025] (1) MoSi2 powder is corroded by a 5% volume fraction hydrofluoric acid aqueous solution, and then placed in a 0.1 mol / L CuCl2 aqueous solution for standing, and then taken out and dried in an argon atmosphere at a temperature of 100°C to obtain copper ion-loaded MoSi2 powder;

[0026] (2) The copper ion-loaded MoSi2 powder in step (1) is ball-mixed with medical titanium alloy powder at a mass ratio of 1:60 to obtain uniformly mixed medical titanium alloy composite powder;

[0027] (3) The medical titanium alloy composite powder in step (2) is sintered at a high temperature of 1200°C to promote the dissolution and diffusion of MoSi2 powder, forming a low-modulus Ti-Mo alloy;

[0028] (4) In a mixed protective atmosphere of methane and argon at a volume ratio of 1:80, a femtosecond laser beam with a power of 0.3 W is scanned on the surface of the low-modulus Ti-Mo alloy in step (3) to promote the in-situ reaction of carbon decomposed from methane gas with Ti, Si and Cu in the low-modulus titanium alloy matrix to form a microporous structure with friction-reducing function Ti5Si3, Ti3SiC2 and antibacterial function Ti3(Cu, Si)C2.

[0029] From Figure 1 It can be found that the in-situ formed microporous structure is loaded with nano Ti5Si3, Ti3SiC2 and Ti3(Cu, Si)C2 phases, and there is no obvious metallurgical defect at the interface between the nano phase and the microporous structure.

[0030] Example 2

[0031] The difference between this embodiment and Example 1 is that the concentration of the CuCl2 aqueous solution in step (1) is 0.3 mol / L.

[0032] Example 3

[0033] The difference between this embodiment and Example 2 is that the mass ratio of MoSi2 powder to medical titanium alloy powder in step (3) is 1:40.

[0034] Example 4

[0035] The difference between this embodiment and Example 3 is that the volume ratio of methane to argon in step (4) is 1:40, and the power of the femtosecond laser beam in step (4) is 1 W.

[0036] Figure 2The wear rate of the low-modulus titanium alloy with the surface wear-reducing / antibacterial composite functional microstructure formed in Examples 1, 2, 3, and 4 is in the range of 6.4-8.6 x 10 -5 mm 3 / N·m, which is lower than the wear rate (about 1.7 x 10 -4 mm 3 / N·m) of the existing ceramic-reinforced titanium alloy micro-porous structure, further indicating that the formation of the in-situ Ti5Si3 and Ti3SiC2 phases in the present application can effectively reduce the wear rate of the titanium alloy. Figure 3 The elastic modulus of the low-modulus titanium alloy with the surface wear-reducing / antibacterial composite functional microstructure formed in Examples 1-4 is in the range of 20-25 GPa, which is lower than the elastic modulus of the conventional medical pure titanium and titanium alloy, and can effectively reduce the "stress shielding" effect.

[0037] The antibacterial rate of the low-modulus titanium alloy with the surface wear-reducing / antibacterial composite functional microstructure formed in Examples 1-4 against Staphylococcus aureus is higher than 99% after 24 hours of testing, which is higher than the antibacterial property (98.1%) of the single silver-doped micro-porous structure. This is mainly due to the fact that the copper ions are used to replace the silicon atoms in the antibacterial functional Ti3(Cu, Si)C2 loaded in the micro-porous structure, which can be continuously released in the human body environment, thereby giving the titanium alloy a sustained antibacterial effect. On the other hand, the concentration of the copper ion solution can be adjusted according to the service time of the medical titanium alloy, thereby realizing the sustained and precise antibacterial function.

[0038] Comparative Example 1

[0039] The specific preparation process is the same as that of Example 1, except that in step (1), the 5% hydrofluoric acid aqueous solution is not used for corrosion and the 0.1 mol / L CuCl2 aqueous solution is not used for static treatment. Instead, the MoSi2 powder is directly mixed with the medical titanium alloy powder by ball milling and then high-temperature sintering, and the micro-porous structure is prepared by the femtosecond laser process.

[0040] Comparative Example 2

[0041] The specific preparation process is the same as that of Example 1, except that in step (4), the methane and argon gas mixture with a volume ratio of 1:80 is not used as the environmental atmosphere, and only argon gas is directly used as the environmental atmosphere, and the micro-porous structure is prepared by the femtosecond laser process.

[0042] The low-modulus titanium alloy with the surface wear-reducing Ti5Si3 and Ti3SiC2 formed in Comparative Example 1 does not have the replacement of copper ions, so the titanium alloy does not have antibacterial function. In Comparative Example 2, only argon gas is used as the environmental atmosphere, and methane gas is not used, so the in-situ carbon source of Ti3SiC2 and Ti3(Cu, Si)C2 phases is lacking, and thus the above two phases are not found in the micro-porous structure. According to experimental calculation, the wear rate is about 3.8 x 10 -4 mm3 N / m, which indicates that the method of the present application can significantly enhance the wear resistance of low-modulus titanium alloys.

Claims

1. A low-modulus titanium alloy with a surface anti-friction / antibacterial composite microstructure, characterized in that, It includes a low-modulus Ti-Mo alloy matrix, and microporous structures of Ti5Si3, Ti3SiC2 with anti-wear function and Ti3(Cu,Si)C2 with antibacterial function loaded on the surface.

2. The low-modulus titanium alloy with a surface-reducing / antibacterial composite microstructure according to claim 1, characterized in that, The microporous structures of Ti5Si3, Ti3SiC2 with anti-wear function and Ti3(Cu,Si)C2 with antibacterial function are formed by the in-situ reaction of carbon from the decomposition of methane gas caused by the high temperature of the femtosecond laser beam with Ti, Si and Cu in the low-modulus Ti-Mo alloy matrix. The mass ratio of Ti5Si3, Ti3SiC2 to Ti3(Cu,Si)C2 is 1:8:1 to 1:2:

1.

3. A method for manufacturing a low-modulus titanium alloy with a surface friction-reducing / antibacterial composite functional microstructure as described in claim 1 or 2, characterized in that, Includes the following steps: (1) After etching MoSi2 powder with hydrofluoric acid aqueous solution, place it in CuCl2 aqueous solution and let it stand before drying to obtain copper ion-loaded MoSi2 powder. (2) The copper ion-loaded MoSi2 powder and medical titanium alloy powder were ball-milled and mixed to obtain a uniformly mixed medical titanium alloy composite powder. (3) Medical titanium alloy composite powder is sintered at high temperature to promote the dissolution and diffusion of MoSi2 powder to form a low-modulus Ti-Mo alloy; (4) In a protective atmosphere of mixed methane and argon, a femtosecond laser beam is used to scan the surface of the low-mode Ti-Mo alloy, which causes the carbon from the decomposition of methane gas to react in situ with Ti, Si and Cu in the low-mode Ti-Mo alloy matrix to form microporous structures with anti-wear function Ti5Si3, Ti3SiC2 and antibacterial function Ti3(Cu,Si)C2.

4. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite microstructure according to claim 3, characterized in that, The concentration of the CuCl2 aqueous solution in step (1) is 0.1–0.3 mol / L.

5. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite functional microstructure according to claim 3, characterized in that, In step (1), the drying environment is an argon atmosphere at a temperature of 100-150°C.

6. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite microstructure according to claim 3, characterized in that, The volume fraction of the hydrofluoric acid aqueous solution in step (1) is 3-5%.

7. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite microstructure according to claim 3, characterized in that, In step (2), the mass ratio of MoSi2 powder to medical titanium alloy powder is 1:40 to 1:

60.

8. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite functional microstructure according to claim 3, characterized in that, The sintering temperature in step (3) is 1200-1500℃.

9. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite functional microstructure according to claim 3, characterized in that, In step (4), the volume ratio of methane to argon is 1:40 to 1:

80.

10. The method for manufacturing a low-modulus titanium alloy with a surface-reducing / antibacterial composite functional microstructure according to claim 3, characterized in that, In step (4), the power of the femtosecond laser beam is 0.3 to 1 W.

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