LU500216B1 - Surface modification method of titanium-molybdenum-zirconium metastable beta-titanium alloy - Google Patents

Abstract

The invention discloses a surface modification method of titanium-molybdenum- zirconium (Ti-Mo-Zr) metastable beta-titanium alloy, which relates to the technical field of surface functionalization modification of medical metal materials. The Ti-Mo-Zr series metastable beta titanium alloy is etched first, and then placed in the mixed aqueous solution of H2O2 and H3PO4 for hydrothermal reaction. By controlling the reaction conditions, the Ti-Mo-Zr series metastable beta titanium alloy with surface modification is finally prepared. The main inorganic element P of bone is successfully mixed into the Ti-Mo-Zr alloy, so that the prepared titanium alloy material has both low elastic modulus and high surface biological activity, and no biological toxic elements, and has a broad application prospect in clinical dental repair, implantation, orthodontics, hard tissue repair and other fields.

Description

DESCRIPTION Surface modification method of titanium-molybdenum-zirconium metastable B- titanium alloy

TECHNICAL FIELD The invention relates to the technical field of surface functional modification of medical metal materials, in particular to a surface modification method of a Ti-Mo-Zr metastable ß titanium alloy.

BACKGROUND Titanium and titanium alloys are widely used in the field of clinical dental implants because of their light weight, good corrosion resistance and biocompatibility, but their elastic modulus (>110GPa) is much higher than that of human jawbone (10-30GPa), which can easily cause long-term "stress shielding and stress stimulation (Stress shielding effect)". "In addition, titanium alloy contains Ni, Al, V and other harmful elements that cause cellular and tissue toxicity, leading to organ damage, bone softening, anemia and neurological disorders and other complications, all these factors make its clinical short- term (5-10 years) restorative effect is significant but long-term efficacy is not good.

At present, domestic and foreign scholars have successively explored and developed a new generation of B-type titanium alloys with lower elastic modulus, such as T1-Nb-Zr- Ta-Fe-Si, Ti-Al-V-Cr-Mo-Zr, Ti-Mo-Nb-Zr, Ti-Nb-Ta-Zr and Ti-V-Cr-Al series, however, most of the systems have too many types of alloying elements and contain biotoxic elements Al, V, and Ni, which not only complicate the study of microscopic formation mechanisms and macroscopic properties of alloys, but also their biosafety for human beings has been questioned [Materials Science and Engineering: A 2016, 665:

154-160, Journal of the Mechanical Behavior of Biomedical Materials 2017, 71: 329- 336, Materials Science and Engineering: C 2016, 60: 230-238]. Therefore, there 1s a need to further ensure that medical titanium alloy materials are free from biotoxic elements on the basis of low elastic modulus. Nearly 30 years of clinical follow-up studies have shown that Zr elements are biocompatible and non-cytotoxic, and Colin Dunstan's team at the University of Sydney found that Zr ions can promote the proliferation and differentiation of human osteoblasts by upregulating the signal expression of bone morphogenetic protein (BMP-2), presenting excellent pro-osteocontegration ability [Plos One 2015, 10(1): e0113426]; Mo is one of the essential trace elements, and its addition in appropriate amounts can substantially improve the mechanical properties, biocompatibility, and corrosion resistance of biomedical alloys [Acta Biomaterialia 2009, 5(1): 399-405, Journal of Materials Science: Materials in Medicine 2007, 18(1): 149-

154.].

At the same time, natural bone trabeculae have a micro/nano multilevel structure (inorganic components are Ca and P), and their extracellular matrix (ECM) is also a micro/nano coexistence structure consisting of nanofibers, pores and augmentations. According to the bionic principle, the modification of implants to obtain a surface with structure and composition similar to natural bone is one of the hot spots in the research of titanium-based biomaterials in recent years, and the common activation modifications are: surface biological and chemical molecular modification, surface etching, spraying nano-hydroxyapatite coating, etc [BioMed research international 2015, 2015: 791725,Chen C. Construction of composite functional coatings of bioactive molecules and bone-like apatite on titanium surfaces. Huazhong University of Science and

Technology, 2013.]. However, the incorporation of P-element, the main inorganic component of bone, and thus the preparation of titanium phosphate structural coatings with micron-nanometer multi-scale on the surface of Ti-Mo-Zr system alloy implants is not yet possible with the current preparation technology.

In view of the above status, it is important to provide a low elastic modulus phosphorus-containing titanium alloy material with micron-nanometer multi-scale and multiple morphological structure surfaces to solve the problems of solid bonding and mechanical matching between traditional titanium alloy implants and bone tissue interfaces and long-term implant stability of dental implants.

SUMMARY The purpose of the present invention is to provide a Ti-Mo-Zr system metastable B titanium alloy surface modification method to solve the above-mentioned problems of the prior art, so that the Ti-Mo-Zr system metastable [ titanium alloy surface not only has a micron-nanometer multi-scale, polymorphic surface morphology, and this surface multi- level structure on the main inorganic components of human bone phosphorus elements, while the material has a low elastic modulus, no biotoxic elements.

(1) Surface pretreatment of titanium alloy material: Acid etching of Ti-Mo-Zr system metastable B titanium alloy to obtain surface pretreated titanium alloy material; (2) Surface modification treatment of titanium alloy material: Place the surface pretreated titanium alloy material in step (1) in a mixed aqueous solution of HO, and H3PO4, and react at 0-300°C and 30-200 kPa for 0-72 h; After the reaction is completed, clean and dry, 1.e., the surface modified Ti-Mo-Zr system metastable ß titanium alloy; In the mixed aqueous solution of H202 and H3PO4, the mass concentration of H:02 1s 3-27% and the mass concentration of H3PO4 is 3-27%.

Further, the acid etching solution is a mixed solution of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3-4:5.

Furthermore, the acid etching treatment time is 30 s-5 min.

Further, after the acid etching treatment in step (1), a cleaning step is further included; The cleaning step is that acetone, absolute ethyl alcohol and ultrapure water are sequentially used for ultrasonic cleaning respectively.

Further, the cleaning time is 10-60 min.

Further, the Ti-Mo-Zr metastable B titanium alloy is Ti-12Mo-10Zr or Ti-18Mo- 13Zr.

The invention also provides a surface-modified Ti-Mo-Zr metastable titanium alloy prepared by the preparation method.

The invention discloses the following technical effects: The main inorganic element P of bone is successfully mixed into the Ti-Mo-Zr alloy, and a micron-nano multi-scale titanium phosphate structure coating is prepared on the surface of the Ti-Zr-Mo alloy implant. The prepared medical titanium alloy material has both low elastic modulus and high surface biological activity, without biological toxic elements. It has a broad application prospect in clinical prostheses, implants, orthodontics, hard tissue repair and other fields.

BRIEF DESCRIPTION OF THE FIGURES In order to explain the embodiments of the present invention or the technical scheme in the prior art more clearly, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in the field, other drawings can be obtained according to these drawings without paying creative labor.

Figure 1 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-12Mo-10Zr alloy of Example 1.

la 1s the scanning electron microscope image of Ti-12Mo-10Zr alloy, 1b, 1c are the elemental distribution of the surface micro and nano structure of the alloy material before and after modification, respectively.

Figure 2 shows the scanning electron microscopy and elemental distribution map of the surface modified Ti-12Mo-10Zr alloy of Example 2.

2a 1s the scanning electron microscope image of Ti-12Mo-10Zr alloy, and 2b, 2c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 3 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-12Mo-10Zr alloy of Example 3.

3a 1s the scanning electron microscope image of T1-12Mo-10Zr alloy, and 3b, 3c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 4 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-12Mo-10Zr alloy of Example 4.

4a 1s the scanning electron microscope image of Ti-12Mo-10Zr alloy, 4b, 4c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 5 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-18Mo-13Zr alloy of Example 5.

Sa is the scanning electron microscope image of Ti-18Mo-13Zr alloy and Sb, Sc are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 6 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-18Mo-13Zr alloy of Example 6.

6a is the scanning electron microscope image of Ti-18Mo-13Zr alloy and 6b, 6c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 7 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-18Mo-13Zr alloy of Example 7.

7a is the scanning electron microscope image of Ti-18Mo-13Zr alloy and 7b, 7c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after the modification, respectively.

Figure 8 shows the scanning electron microscopy and elemental distribution of the surface modified Ti-18Mo-13Zr alloy of Example 8.

8a is the scanning electron microscope image of Ti-18Mo-13Zr alloy, 8b, 8c are the elemental distribution maps of the surface micro and nano structures of the alloy material before and after modification, respectively.

DESCRIPTION OF THE INVENTION Various exemplary embodiments of the present invention will now be described in detail, which should not be regarded as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics and embodiments of the present invention.

It should be understood that the terms described in the present invention are only for describing specific embodiments, and are not intended to limit the present invention. In addition, as for the numerical range in the present invention, it should be understood that every intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Intermediate values within any stated value or stated range and every smaller range between any other stated value or intermediate values within the stated range are also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

Unless otherwise stated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the present invention relates. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and/or materials related to the documents. In case of conflict with any incorporated documents, the contents of this specification shall prevail.

Without departing from the scope or spirit of the invention, it is obvious to those skilled in the art that many modifications and changes can be made to the specific embodiments of the specification of the invention. Other embodiments derived from the description of the present invention will be apparent to the skilled person. The specification and embodiment of that present invention are merely exemplary.

As used herein, "including", "comprising", "having", "containing", etc. are all open terms, which means including but not limited to.

Example 1 Cutting Ti-12Mo-10Zr alloy into circular pieces with a diameter of ®10 mmx1 mm, and polishing them smoothly with 400-2000 mesh sandpaper in turn; Immersing the polished Ti-12Mo-10Zr in a mixed solution of hydrofluoric acid, nitric acid and water at a volume ratio of 1:3:5 for acid etching for Smin to perform chemical polishing, sequentially ultrasonically cleaning with acetone, absolute ethanol and ultrapure water for min, taking out the Ti-12Mo-10Zr alloy sheet, and keeping the temperature at 37°C.

Then, high-energy hydrothermal method was used to place the clean Ti-12Mo-10Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H>0,+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep it sealed. The reaction temperature was set at 100°C and the reaction pressure was 150 kpa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, Ti-12Mo-10Zr alloy surface forms a "petal-like" tightly arranged structure, as shown in Figure la, where the "petal" is formed by the radiation combination of several slab-like materials, and the "petal" diameter is 5-15 um, the transverse width of the slabs is 1-3 um, and the thickness is 100-200 nm. Figure 1b and Figure lc respectively show the element distribution diagram of the micro-nano structure on the surface of Ti-12Mo-10Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only T1, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy is covered by a coating composed of Ti, O and P.

Example 2 The Ti-12Mo-10Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished Ti-12Mo- 10Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid etching for 5 min for chemical polishing. The polished Ti-12Mo- 10Zr was successively cleaned with acetone, anhydrous ethanol and ultra-pure water for 30min respectively, and then kept at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-12Mo-10Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H>0,+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep it sealed. The reaction temperature was set at 140°C and the reaction pressure was 150 kPa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. The micrometer "carnation" flower structure was formed on the surface of Ti-12Mo-10Zr alloy after the above treatment, as shown in Figure 2a. The micrometer "carnation" flower structure was composed of several nanosheets radiating outwardly from the center of the sphere. The diameter of the micrometer flower structure was 5-10 um, and the transverse diameter of the nanostrips was 1-2 um. Thickness is 80-100 nm. Figure 2b and 2c respectively show the elemental distribution of the micro-nano structure on the surface of Ti-12Mo-10Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only T1, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy is covered by a coating composed of Ti, O and P.

Example 3 The Ti-12Mo-10Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished Ti-12Mo- 10Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid etching treatment for 5 min for chemical polishing. After ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30 min successively, Ti-12Mo-10Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-12Mo-10Zr alloy sheet after the pretreatment above into the PTFE lined pressure cooker. The mixed aqueous solution with a mass ratio of 27% H20> +3% H:PO4 was added into the reaction kettle. The lid of the reaction kettle was tightened to keep it sealed, and the closed reaction kettle was put into the electric thermostatic blast dryer for 24 h. The reaction temperature was set at 180°C and the reaction pressure was 150 kpa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti-12Mo-10Zr alloy forms a micron-scale brush-like structure, in which the micron-scale brush-like structure is composed of a number of nano-needle rods piled up in disorder. As shown in Figure 3a, the length of the nano-needle rods is 5-15 um, and the diameter 1s 80-150 nm. Figure 3b and 3c respectively show the element distribution diagram of micro-nano structure on the surface of Ti-12Mo-10Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only Ti, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy is covered by a coating composed of Ti, O and P.

Example 4 The Ti-12Mo-10Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished Ti-12Mo- 10Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid etching treatment for Smin for chemical polishing. After ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30 min successively, Ti-12Mo-10Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-12Mo-10Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H>0,+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep it sealed. The reaction temperature was set at 220°C and the reaction pressure was 150 kPa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti- 12Mo-10Zr alloy forms a micron-level brush-like structure, in which the micron-level brush-like structure is composed of a number of nano-needles in disorder. As shown in Figure 4a, the nano-needle rods are smooth and smooth without beading phenomenon, and the length of each nano-needle rod is 5-15 um, and the diameter is 80-120 nm. Figure 4b and 4c respectively show the elemental distribution of the micro-nano structure on the surface of Ti-12Mo-10Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only T1, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy 1s covered by a coating composed of Ti, O and P.

Example 5 The Ti-18Mo-13Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished Ti-18Mo- 13Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid etching treatment for 5 min for chemical polishing. After ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30 min successively, Ti-18Mo-13Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-18Mo-13Zr alloy sheet after the pretreatment above into the PTFE lined pressure cooker. The mixed aqueous solution with a mass ratio of 27% H»>0,+3% H3PO4 was added into the pressure cooker for 24 h reaction. The reaction temperature was set at 100°C and the reaction pressure was 150 kPa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti-18Mo-13Zr alloy forms a nano-porous sandlike structure, as shown in Figure 5a, in which the porous sandlike structure is composed of numerous leaf-like structures, and the pore size of the porous structure is 100-400 nm. Figure 5b and Sc respectively show the elemental distribution of the micro-nano structure on the surface of Ti-18Mo-13Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only

Ti, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy 1s covered by a coating composed of Ti, O and P.

Example 6 The Ti-18Mo-13Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished T1-18Mo- 13Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid etching treatment for 5 min for chemical polishing. After ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30 min successively, Ti-18Mo-13Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-18Mo-13Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H20>+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep 1t sealed. The reaction temperature was set at 140°C and the reaction pressure was 150 kPa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti- 18Mo-13Zr alloy presents a uniform and dense multi-level micro-nano lamellar structure, which is perpendicular to the surface of titanium alloy substrate, as shown in Figure 6a, with a width of 300-700 nm and a thickness of 50-100 nm. Figure 6b and 6¢ show that after hydrothermal modification, the surface of Ti-18Mo-13Zr alloy material is uniformly covered by a coating composed of T1, O and P elements.

Example 7

The Ti-18Mo-13Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished T1-18Mo- 13Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid-etching treatment for Smin for chemical polishing, followed by ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30 min respectively. Ti-18Mo-13Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-18Mo-13Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H>0,+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep 1t sealed. The reaction temperature was set at 180°C and the reaction pressure was 150 kPa. After the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti- 18Mo-13Zr alloy forms a micron-sized porous grass structure, in which the porous grass structure is composed of a number of nanometer bars stacked in disorder. As shown in Figure 7a, the length of the nanometer bars is 5-20 um, and the diameter is 100-200 nm. Figure 7b and 7c respectively show the elemental distribution of the micro-nano structure on the surface of Ti-18Mo-13Zr alloy material before and after modification in this embodiment. It can be seen that the surface of the alloy contains only Ti, O, Mo and Zr elements before modification. After hydrothermal modification, the surface of the alloy is covered by a coating composed of Ti, O and P.

Example 8

The Ti-18Mo-13Zr alloy was cut into a round piece of ®10 mmx1 mm, and polished smooth with 400-2000 mesh sandpaper successively. The polished T1-18Mo- 13Zr was immersed in a mixture of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3:5 for acid-etching treatment for Smin for chemical polishing, followed by ultrasonic cleaning with acetone, anhydrous ethanol and ultra-pure water for 30min respectively. Ti-18Mo-13Zr alloy sheets were taken out and placed at 37°C for constant temperature.

Then, high-energy hydrothermal method was used to place the clean Ti-18Mo-13Zr alloy sheet after the pretreatment above into the PTFE reaction kettle. The mixed aqueous solution with a mass ratio of 27% H>0,+3% H3;PO4 was added into the reaction kettle. The lid of the kettle was tightened to keep 1t sealed. The reaction temperature was set at 220°C and the reaction pressure was 150 kPa. After the end of the reaction, the sample was taken out and rinsed with deionized water for several times to fully remove the residual reactants. The sample was dried at 37°C. After the above treatment, the surface of Ti-18Mo-13Zr alloy forms a micron-level porous grass structure, in which the micron- level porous grass structure is composed of a number of nano-needle rods in disarray. As shown in Figure 8a, the length of the nano-needle rods is 10-30 um, and the diameter is 80-200 nm. Figure 8b and 8c show that after hydrothermal treatment, the coating on the surface of Ti-18Mo-13Zr alloy material is mainly composed of Ti, O and P elements, indicating the formation of phosphorylated titanium.

This invention preparation of Ti-Mo-Zr is metastable ß titanium alloy surface micro - nano scales, various morphology structure, the micro-scale structure as a bundle of flower petals shape/shape/fiber/porous microspheres morphology structure and size of 5-

50 microns, nanoscale morphology structure for nano strip, slice, nanorods, nano needle shape structure, The length of nanoribbons, nanoribbons, nanoribbons and nanoribbons is 5-50 um, and the transverse diameter/width is 20-500 nm. The micron structure is assembled by the nanoribbons.

In the surface micron-nano multi-scale and various morphologies and structures of Ti-Mo-Zr metastable ß titanium alloy prepared by the invention, the micron-scale morphology and structure are flower shape/petal shape/fiber bundle/porous microsphere with the size of 5-50 um, and the nano-scale morphology and structure are nanoscale strip, nanoscale sheet, nanoscale rod and nanoscale needle. The length of nanoribbons, nanoribbons, nanoribbons and nanoribbons is 5-50 um, and the transverse diameter/width is 20-500 nm. The micron structure is assembled by the nanoribbons.

The compressive elastic modulus and compressive yield strength of the Ti-Mo-Zr metastable B-titanium alloy prepared in Embodiments 1-8 of the present invention are shown in Table 1.

Table 1 Modulus of elasticity in Compressive yield compression/GPa strength/Mpa (off set 0.2%) Example 1 435.79 Example 2 436.72 Example 3 435.96 Example 4 435.48 Example 5 814.32 Example 6 814.67 Example 7 813.56 Example 8 814.95

In the process of hydrothermal reaction, reaction conditions, such as reaction time, reaction mixture ratio, temperature and pressure, will affect the size, morphology/shape, distribution, thickness, structure density and the proportion of P element on the surface. Poor or improper reaction conditions will cause different degrees of damage to the formed structure.

The above embodiments only describe the preferred mode of the invention, but do not limit the scope of the invention. On the premise of not departing from the design spirit of the invention, various modifications and improvements made by ordinary technicians in the field to the technical scheme of the invention shall fall within the protection scope determined by the claims of the invention.

Claims (7)

CLAIMS:

1. A surface modification method of Ti-Mo-Zr metastable B titanium alloy, which is characterized in that it comprises the following steps: (1) surface pretreatment of titanium alloy material: acid etching of Ti-Mo-Zr system metastable ß titanium alloy to obtain surface pretreated titanium alloy material; (2) surface modification treatment of titanium alloy material: place the surface pretreated titanium alloy material in step (1) in a mixed aqueous solution of H:02 and H3PO4, and react at 0-300°C and 30-200 kPa for 0-72 h; after the reaction is completed, clean and dry, i.e, the surface modified Ti-Mo-Zr system metastable ß titanium alloy; in the mixed aqueous solution of H,O, and H:PO4, the mass concentration of HO» is 3- 27% and the mass concentration of H3PO4 1s 3-27%.

2. The method for surface modification of Ti-Mo-Zr metastable ß titanium alloy according to claim 1, wherein the acid etching solution is a mixed solution of hydrofluoric acid, nitric acid and water with a volume ratio of 1:3-4:5.

3. The surface modification method of Ti-Mo-Zr metastable B titanium alloy according to claim 1, wherein the acid etching treatment time is 30 s-5 min.

4. The surface modification method of Ti-Mo-Zr metastable titanium alloy according to claim 1, wherein after the acid etching treatment in step (1), a cleaning step is further included; the cleaning step is that acetone, absolute ethyl alcohol and ultrapure water are sequentially used for ultrasonic cleaning respectively.

5. The surface modification method of Ti-Mo-Zr metastable B titanium alloy according to claim 4, wherein the cleaning time 1s 10-60 min.

6. The surface modification method of Ti-Mo-Zr metastable B titanium alloy according to claim 1, wherein the Ti-Mo-Zr metastable B titanium alloy is Ti-12Mo-10Zr or Ti-18Mo- 13Zr.

7. À surface-modified Ti-Mo-Zr metastable B titanium alloy prepared by the preparation method according to any one of claims 1-6.