An antibacterial Zr-Nb alloy, powder and laser additive manufacturing method for hip joints

Abstract

The present invention provides an antibacterial Zr-Nb alloy for hip joints, powder and a laser additive manufacturing method, belonging to the technical field of metal materials. The Zr-Nb alloy is suitable for gas atomization powder making. The Zr-Nb alloy is composed of Zr, Nb, Cu and inevitable impurities. By mass percentage, Nb: 25-30%, Cu: 8-10%. By limiting the composition of the Zr-Nb alloy, it is ensured that it can be suitable for gas atomization powder making, avoiding segregation during the powder making process, resulting in poor tissue homogeneity and cracks under the action of external forces.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal materials, and particularly relates to an antibacterial Zr-Nb alloy for hip joints, a powder, and a laser additive manufacturing method. Background Art

[0002] Total hip arthroplasty has become the main method for treating severe femoral head necrosis in young and middle-aged patients due to its advantages such as rapid recovery, effective improvement of quality of life, and few complications. The activity intensity and frequency of hip joints in young and middle-aged patients are much greater than those of the elderly, so higher requirements are put forward for the service life of prostheses. Wear particles and osteolysis caused by the friction interface of the prosthesis are important factors affecting the service life of the prosthesis after hip replacement and ultimately leading to failure.

[0003] In the prior art, for example, the invention patent with the publication number CN112404431B discloses an oxidized zirconium-niobium alloy hip joint prosthesis system and a preparation method thereof. By forming an oxide layer on the surfaces of the femoral head and the liner after oxidation, super wear resistance and low wear rate of the friction interface are achieved. However, in this scheme, it is difficult to control the thickness of the oxide layer. If the thickness is thin, the anti-wear performance is poor, while if the thickness is thick, cracks may occur between the oxide layer and the matrix. The Pilling-Bedworth ratio (PBR) is used to characterize whether the metal oxide layer has a protective effect. When the PBR value is between 1 and 2.5, the oxide film formed by the metal oxide generally has good protection. If the PBR value is too large, due to the volume expansion of the metal oxide, stress is generated in the surface film, causing cracks in the oxide film, which is not conducive to the growth of the oxide film. Secondly, artificial joints are often sensitive to bacterial adhesion and are more likely to cause bacterial infections. In order to endow the material surface with antibacterial properties, it is necessary to construct an antibacterial surface targeted according to the occurrence mechanism of bacterial infections and endow it with antibacterial properties to reduce the adhesion and reproduction of bacteria and thus avoid the occurrence of infections. The invention patent with the publication number CN102676985A uses the glow ion nitriding technology to prepare an antibacterial copper-permeated layer on the surface of medical titanium alloy. Wu Haibo et al. sputtered Ti-Cu films on the surface of medical pure titanium using magnetron sputtering technology, and combined micro-arc oxidation and ion high-temperature nitriding technologies to prepare Cu-TiO2 and Ti-Cu-N antibacterial coatings. However, in this technical scheme, the mixed titanium alloy powder and copper powder are used, and it is very difficult to mix the two well even with a high-energy ball mill. Therefore, it is an urgent problem to prepare a Zr-Nb alloy with good wear resistance, antibacterial property, and suitable for gas atomization powder making process. Summary of the Invention

[0004] To solve the above problems, the present invention provides an antibacterial Zr-Nb alloy for hip joints, a powder, and a laser additive manufacturing method. By limiting the composition of the Zr-Nb alloy, it is ensured that it is applicable to gas atomization powder making, avoiding segregation during the powder making process, resulting in poor tissue homogeneity and cracks under the action of external forces.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides an antibacterial Zr-Nb alloy for hip joints. The Zr-Nb alloy is suitable for gas atomization powder making. The Zr-Nb alloy is composed of Zr, Nb, Cu and inevitable impurities. By mass percentage, Nb: 25-30%, Cu: 8-10%.

[0007] Further, Nb: 28%, Cu: 8%.

[0008] The present invention also provides an antibacterial Zr-Nb alloy powder for hip joints. The Zr-Nb alloy powder is obtained by gas atomization powder making of the above Zr-Nb alloy.

[0009] The present invention also provides a preparation method of an antibacterial Zr-Nb alloy powder for hip joints. Weigh the source materials of Zr, Nb, and Cu according to mass percentage; melt the source materials of Zr, Nb, and Cu to make a casting rod, and use the casting rod as a consumable electrode and perform gas atomization powder making.

[0010] Further, the source materials of Zr, Nb, and Cu are Zr-Cu alloy, Nb-Cu alloy, and Zr metal.

[0011] Further, vacuum melt the source materials of Zr, Nb, and Cu. After complete melting, pour them into a casting rod. The casting rod is turned over and remelted at least three times; use the prepared casting rod as a consumable electrode. In a vacuum environment, perform primary gas atomization and secondary gas atomization on the melted melt of the casting rod; the primary gas atomization uses an annular nozzle, the gas pressure is 2.9-3.0 MPa, and the converging angle of the gas outlet is 22-25°; the secondary gas atomization uses an annular nozzle, the gas pressure is 1.8-2.2 MPa, and the converging angle of the gas outlet is 32-35°. The temperature range of the action interval of the secondary gas atomization is 400-500 °C; screen the preliminarily prepared Zr-Nb alloy powder to obtain the product.

[0012] Further, through screening, a Zr-Nb alloy powder with a particle size between 300 and 500 mesh is obtained.

[0013] The present invention also provides a method for preparing a hip joint using an antibacterial Zr-Nb alloy. The hip joint is prepared by selective laser melting using the above Zr-Nb alloy powder or the Zr-Nb alloy powder prepared by the above preparation method, and includes the following steps: obtaining 3D data by CT scanning the hip joint of a patient, and performing layer slicing on the model; importing the 3D data after layer slicing into a laser 3D printing system to perform 3D printing and precision forming of the hip joint blank with the Zr-Nb alloy powder; performing hot isostatic pressing treatment and cryogenic treatment on the prepared hip joint blank, machining, polishing, cleaning and drying the obtained product, and then putting it into a mixed gas of nitrogen and oxygen for nitriding and oxidizing treatment to obtain the hip joint.

[0014] Further, in the modeling process, a body-centered cubic unit cell is adopted, and the porosity is controlled by controlling the diameter of the struts constituting the body-centered cubic.

[0015] Further, the prepared hip joint is subjected to hot isostatic pressing treatment and cryogenic treatment, including: subjecting the prepared hip joint blank to hot isostatic pressing treatment. The hot isostatic pressing process is: heating to 1200-1300 °C under an argon protection atmosphere, maintaining at a pressure of 120-160 MPa for 6 h, and cooling with the furnace; then reducing the hip joint blank after hot isostatic pressing treatment to -60~-70 °C at a rate of 2-4 °C / min and holding for at least 2 h, and then putting it into liquid nitrogen and holding for at least 5 h; in the mixed gas of nitrogen and oxygen, the proportion of oxygen is 5-8%, the total flow rate is 60-80 ml / min, first heating to 200 °C and holding for 30-50 min, then heating to 500-600 °C and holding for 5-6 h, and then cooling to 400-450 °C and holding for at least 10 h.

[0016] The beneficial effects brought by the technical solutions provided by the embodiments of the present invention include:

[0017] The Zr-Nb alloy for hip joints provided by the present invention needs to meet the following requirements: (1) It is applicable to the preparation of hip joints. Since the hip joints bear large pressures, the yield strength of the solid sample is generally required to be above 500 MPa, and the yield strength of the trabecular bone is above 15 MPa; (2) Cu in the alloy can form a Cu-N antibacterial layer. If the content of Cu is low, the area occupied by the formed Cu-N antibacterial layer is small, and effective antibacterial effects cannot be achieved. Secondly, if the area occupied by the Cu-N antibacterial layer is large, the area occupied by the Zr-O layer is small, and the wear resistance of the prepared product is poor. Therefore, the ratios of Zr, Nb, and Cu in this application are strictly limited; (3) To meet the powder preparation requirements, selective laser sintering using 3D printing is adopted. The prepared powder needs to have a certain degree of sphericity for subsequent printing. Secondly, the material properties and composition of the prepared material need to be uniform and have a high yield rate, and problems such as severe segregation, satellite powder, and abnormal powder should not occur; (4) Magnetic compatibility is required to avoid the problem of artifacts generated in strong magnetic field diagnosis due to high magnetic susceptibility in the prior art. The technical solution provided by the present invention only contains Zr, Nb, and Cu elements, which avoids severe segregation caused by the addition of multiple elements and poor uniformity of the mechanical properties of the prepared product. On the other hand, the content is controlled to meet the above requirements. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a body-centered cubic unit cell provided by an embodiment of the present invention;

[0020] Figure 2 It is an electron microscope image of the Zr-Nb alloy powder prepared in Example 1 of the present invention;

[0021] Figure 3 It is a morphology image of the Zr-Nb alloy block prepared in Example 4 of the present invention with different reduction amounts;

[0022] Figure 4 It is a microstructure image of the Zr-Nb alloy block prepared in Example 4 of the present invention;

[0023] Figure 5 It is an electron microscope image of the Zr-Nb alloy powder prepared in Comparative Example 1 of the present invention;

[0024] Figure 6 It is a morphology image of the Zr-Nb alloy block prepared in Comparative Example 1 of the present invention after fracturing;

[0025] Figure 7 Morphology diagrams of Zr-Nb alloy blocks prepared in Comparative Example 1 of the present invention with different reduction ratios;

[0026] Figure 8 Microstructure morphology diagram of the Zr-Nb alloy block prepared in Comparative Example 1 of the present invention. Detailed implementation manners

[0027] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further elaborated in detail below in conjunction with the accompanying drawings and specific embodiments. The specific implementation manners of the present invention are not limited to the specific embodiments given here. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the disclosed specific embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific implementation manners and do not limit the present invention.

[0029] An antibacterial Zr-Nb alloy for hip joints provided by an embodiment of the present invention, the Zr-Nb alloy is suitable for gas atomization powder making, and is characterized in that the Zr-Nb alloy is composed of Zr, Nb, Cu and inevitable impurities. By mass percentage, Nb: 25-30%, Cu: 8-10%.

[0030] The Zr-Nb alloy for hip joints provided by the present invention needs to meet the following requirements: (1) It is suitable for preparing hip joints. The hip joint bears a large pressure. Generally, the yield strength of the solid sample is required to be above 500 MPa, and the yield strength of the trabecular bone is above 15 MPa; (2) Cu in the alloy can form a Cu-N antibacterial layer. If the content of Cu is low, the area occupied by the formed Cu-N antibacterial layer is small, and an effective antibacterial effect cannot be achieved. Secondly, if the area occupied by the Cu-N antibacterial layer is large, the area occupied by the Zr-O layer is small, and the wear resistance of the prepared product is poor. Therefore, the ratios of Zr, Nb and Cu in this application are strictly limited; (3) To meet the powder making requirements, selective laser sintering by 3D printing is used. The prepared powder needs to have a certain sphericity for subsequent printing. Secondly, the material properties and components of the prepared material need to be uniform and have a high yield rate, and problems such as severe segregation, satellite powder and abnormal powder cannot occur; (4) Magnetic compatibility to avoid the problem of artifacts generated by high magnetic susceptibility in strong magnetic field diagnosis in the prior art. The technical solution provided by the present invention only contains Zr, Nb and Cu elements, which avoids severe segregation caused by the addition of multiple elements and poor uniformity of the mechanical properties of the prepared product. On the other hand, its content is controlled to meet the above requirements.

[0031] Preferably, Nb: 28%, Cu: 8%.

[0032] An embodiment of the present invention also provides an antibacterial Zr-Nb alloy powder, which is obtained by gas atomization of the above Zr-Nb alloy.

[0033] An embodiment of the present invention also provides a preparation method of the above antibacterial Zr-Nb alloy powder for hip joints, including:

[0034] S10. Weigh the source materials of Zr, Nb, and Cu according to mass percentages.

[0035] It can be understood that the source materials of Zr, Nb, and Cu are materials that provide the sources of Zr, Nb, and Cu elements, and can be elemental metals or alloys. As a preference of the embodiment of the present invention, the source materials of Zr, Nb, and Cu are Zr-Cu alloy, Nb-Cu alloy, and Zr metal. During the batching process, Nb-Cu alloy is preferably used to meet the required amounts of Nb and copper, and then Zr-Cu alloy and Zr metal are considered. Since the melting point of Nb element is relatively high, reaching 2468 °C, and Nb-Cu alloy can greatly reduce the melting temperature, avoiding the volatilization problem of Cu or Zr elements at high temperatures during the smelting process.

[0036] S11. Melt the source materials of Zr, Nb, and Cu to make a casting rod, and use the casting rod as a consumable electrode for gas atomization to make powder.

[0037] The source materials of Zr, Nb, and Cu are subjected to vacuum melting. After complete melting, they are poured into a casting rod. The casting rod is flipped and remelted at least three times to improve the uniformity of the element distribution in the prepared casting rod. Specifically, the vacuum environment is not greater than 10 Pa, and a medium-frequency induction melting furnace is used for melting. The melting current is 100 - 110 A, and the melting time is 30 - 50 min. After the materials are completely melted, refining is carried out, and after refining is completed, it is poured into a mold to obtain an alloy casting rod with a diameter of 50 - 60 mm and a length of 50 - 100 cm, which is used as a consumable electrode for subsequent gas atomization to make powder.

[0038] The gas atomization powder preparation process is as follows: using the prepared casting rod as a consumable electrode, in a vacuum environment, performing primary gas atomization and secondary gas atomization on the melt after melting the casting rod; the primary gas atomization uses an annular nozzle, the gas pressure is 2.9 - 3.0 MPa, and the gas outlet convergence angle is 22 - 25°; the secondary gas atomization uses an annular nozzle, the gas pressure is 1.8 - 2.2 MPa, the gas outlet convergence angle is 32 - 35°, and the temperature range of the action interval of the secondary gas atomization is 400 - 500 °C; the primary gas atomization is used to crush the melt, and the liquid droplets after crushing are spherical under the action of surface tension. However, at this time, the liquid is prone to collision and adhesion, resulting in poor sphericity of the powder. In this application, by controlling the contents of Zr, Nb, and Cu, combined with secondary gas atomization, and setting the temperature range of the action interval of the secondary gas atomization at 400 - 500 °C, qualified powder with a recovery rate of up to 80% can be prepared, and the sphericity is high. By statistically analyzing fifty samples at ten different positions in a batch, the sphericity is above 90%. The main reason is that although adding the Cu element will cause segregation problems, it also brings corresponding advantages, that is, the synchronization of the solidification time on the surface and inside of the liquid droplet increases, and satellite powder can be effectively removed through secondary gas atomization without increasing the surface irregularity.

[0039] Specifically, the gas atomization powder preparation process of this application is as follows: under a vacuum degree not greater than 0.01 Pa, inert gas is ejected through an annular nozzle to break the metal melt, the gas flow pressure is 10 - 12 Mpa, the inert gas in the primary gas atomization preferably uses argon containing 1% nitrogen by volume ratio, and the secondary gas atomization preferably uses pure argon. Since the nitriding of the alloy is difficult, adding a small amount of nitrogen during the gas atomization powder preparation process can perform a certain amount of nitriding on the powder, and due to the limitation of elements in this application, the subsequent nitrides are prone to aggregation on the surface of the prepared product.

[0040] S12 is obtained by screening the preliminarily prepared Zr - Nb alloy powder. Specifically, through screening, Zr - Nb alloy powder with a particle size between 300 - 500 mesh is obtained.

[0041] The embodiment of the present invention also proposes a method for preparing a hip joint with an antibacterial Zr - Nb alloy. Using the above - mentioned Zr - Nb alloy powder, it includes the following steps:

[0042] S20 Obtain 3D data by CT scanning the hip joint of the patient, and perform layer - by - layer slicing processing on the model.

[0043] In the modeling process, a body - centered cubic unit cell is used, which is composed of four diagonal struts, as Figure 1As shown, the porosity is controlled by controlling the diameter of the struts that make up the body-centered cubic. During the printing process, to ensure printing accuracy and control defects during printing, the minimum strut diameter is limited to 400 µm and the strut length is within 2 mm. Within the above range, regions with different porosities can be well connected without stress concentration.

[0044] S21 Import the 3D data after layer slicing into a laser 3D printing system to perform 3D printing precision forming of the hip joint blank with Zr-Nb alloy powder.

[0045] Specifically, in the 3D printing system, the laser forming process parameters are: laser power is 120 - 150 W, scanning speed is 150 - 180 mm / s, scanning spacing is 50 - 60 µm, laser spot is 60 - 70 µm, and powder spreading thickness is 10 - 40 µm.

[0046] S22 Perform hot isostatic pressing treatment and cryogenic treatment on the prepared hip joint blank.

[0047] Specifically, it includes: performing hot isostatic pressing treatment on the prepared hip joint blank. The hot isostatic pressing process is: under an argon protection atmosphere, heat up to 1200 - 1300 °C, hold for 6 h under a pressure of 120 - 160 MPa, and cool with the furnace; then reduce the hip joint blank after hot isostatic pressing treatment to -60~-70 °C at a rate of 2 - 4 °C / min and hold for at least 2 h, and then place it in liquid nitrogen and hold for at least 5 h.

[0048] S23 Perform machining, polishing, cleaning, and drying on the obtained product, and then place it in a mixed gas of nitrogen and oxygen for nitriding and oxidation treatment to obtain the hip joint.

[0049] In the mixed gas of nitrogen and oxygen, the proportion of oxygen is 5 - 8%, the total flow rate is 60 - 80 ml / min. First, heat up to 200 °C and hold for 30 - 50 min, then heat up to 500 - 600 °C and hold for 5 - 6 h, and then cool down to 400 - 450 °C and hold for at least 10 h.

[0050] It should be noted that the wear-resistant layer in this application is mainly achieved through Zr-O, and the antibacterial layer is mainly achieved through Cu-N / Cu-O. Through stepwise heat preservation, at a temperature of 200 °C, an oxide layer is mainly formed. When the temperature rises to 500 - 600 °C, the formation of nitrides increases to improve the formation of the Cu-N antibacterial layer. Secondly, due to the mixed distribution of the wear-resistant layer and the antibacterial layer on the substrate, there is an internal stress problem. Therefore, annealing coordination is carried out on the interfaces of oxides or nitrides with different properties at a temperature of 400 - 500 °C to avoid film cracking caused by stress concentration. By measuring different regions, on the surface of the wear-resistant layer with antibacterial effect prepared in this application, the proportion of the Cu-N film reaches 7 - 8%, which can effectively carry out antibacterial, the proportion of the Cu-O film does not exceed 2%, and the rest is mainly Zr-O. Secondly, the addition of the Cu-N layer in the present invention can coordinate with the Zr-O layer, reducing the requirement for the thickness of the Zr-O layer.

[0051] Characterization methods:

[0052] 1) Magnetic susceptibility. The measurement method of magnetic susceptibility refers to GB / Z 26082-2010 "Measurement Method of DC Magnetic Susceptibility (Magnetic Moment) of Nanomaterials". The specific method is as follows: Cut a mm square sample from the ingot by wire cutting, polish the surface oxide scale with metallographic sandpaper, and then place it in a vibrating magnetometer (VSM) with a magnetic field strength of 3T and the magnetic field direction perpendicular to the mm plane. The obtained data is linearly fitted using origin software, and the slope of the straight line is the mass magnetic susceptibility (χm), and then it is converted into the volume magnetic susceptibility (χv). The formula is χv = χm × ρ × 4π, (ρ is the alloy density, and π is the pi).

[0053] 2) Elastic modulus. The measurement method of elastic modulus refers to GB / T 8653-2007 "Test Methods for Elastic Modulus, Chord Modulus and Tangent Modulus of Metallic Materials". The specific measurement method is as follows: Cut a square with specific dimensions from the ingot by wire cutting, carry out corresponding heat treatment processes, and then further process it by wire cutting to obtain a tensile specimen. Use a universal tensile testing machine equipped with an optical extensometer to conduct a tensile test to obtain a stress-strain curve, and perform linear fitting on it to obtain the corresponding elastic modulus.

[0054] 3) Yield strength. According to the GB / T 7314-2017 standard, the compressive properties of metallic materials at room temperature are measured.

[0055] 4) Antibacterial test: Staphylococcus aureus was selected as the test subject, and the antibacterial performance of the artificial hip joint was detected according to QB / T2591-2003 "Antibacterial Plastics - Test Methods for Antibacterial Properties and Antibacterial Effects". The results showed that after one day of the test, the antibacterial rate of the titanium alloy hip joint against Staphylococcus aureus reached 99%, and the antibacterial rate still reached 98% after 4 days of the test, indicating good and persistent antibacterial performance.

[0056] 5) Wear detection: A microhardness tester (MHVS-1000PLUS, Shanghai Aolong Xingdi Testing Equipment Co., Ltd., China) was used to measure the microhardness of the femoral stem of the example. The test load was 0.05 kg, the specimen load time was 25 s, and 8 points were taken for each specimen to calculate its average hardness.

[0057] 6) Bonding strength between the film and the substrate: A 2% strain was applied to the hip joint and repeated 100,000 times to observe the state of the film.

[0058] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0059] Embodiment 1: The present invention provides a method for preparing an antibacterial Zr-Nb alloy powder for hip joints, including:

[0060] S10 Weigh the Zr, Nb, and Cu source materials according to mass percentages.

[0061] Weigh the Zr, Nb, and Cu source materials according to Nb: 28%, Cu: 8%, and Zr: 64%.

[0062] S11 The Zr source material, Nb source material, and Cu source material are melted to form a casting rod, and the casting rod is used as a consumable electrode and subjected to gas atomization to produce powder.

[0063] The Zr source material, Nb source material, and Cu source material are subjected to vacuum melting. After complete melting, they are poured into a casting rod, and the casting rod is flipped and remelted three times to improve the uniformity of the element distribution in the prepared casting rod.

[0064] The gas atomization powder preparation process is as follows: The prepared casting rod is used as a consumable electrode. In a vacuum environment, the melted melt of the casting rod is subjected to primary gas atomization and secondary gas atomization; the primary gas atomization uses an annular nozzle, the gas pressure is 2.9 MPa, and the outlet gas convergence angle is 22°; the secondary gas atomization uses an annular nozzle, the gas pressure is 1.8 MPa, and the outlet gas convergence angle is 32°. The temperature range of the action interval of the secondary gas atomization is 400 °C.

[0065] S12 screens the preliminarily prepared Zr-Nb alloy powder. Through screening, Zr-Nb alloy powder with a particle size between 300 and 500 mesh is obtained.

[0066] The prepared Zr-Nb alloy powder is as Figure 2 shown. It can be seen that the powder has good sphericity and few satellite powders.

[0067] Example 2: The embodiment of the present invention provides a method for preparing an antibacterial Zr-Nb alloy powder for hip joints, including:

[0068] S10 Weigh the Zr, Nb, and Cu source materials according to mass percentages.

[0069] Weigh the Zr, Nb, and Cu source materials according to Nb: 25%, Cu: 5%, Zr: 70%.

[0070] S11 Melt the Zr source material, Nb source material, and Cu source material to make an ingot, and use the ingot as a consumable electrode and perform gas atomization to make powder.

[0071] Vacuum melt the Zr source material, Nb source material, and Cu source material. After complete melting, pour it into an ingot, and the ingot is flipped and remelted three times to improve the uniformity of the element distribution in the prepared ingot.

[0072] The gas atomization powder-making process is as follows: Use the prepared ingot as a consumable electrode. In a vacuum environment, perform primary gas atomization and secondary gas atomization on the melted melt of the ingot; the primary gas atomization uses an annular nozzle, the gas pressure is 2.9 MPa, and the outlet convergence angle is 23°; the secondary gas atomization uses an annular nozzle, the gas pressure is 2 MPa, and the outlet convergence angle is 34°, and the temperature range of the action interval of the secondary gas atomization is 450 °C.

[0073] S12 screens the preliminarily prepared Zr-Nb alloy powder. Through screening, Zr-Nb alloy powder with a particle size between 300 and 500 mesh is obtained.

[0074] The prepared Zr-Nb alloy powder has good sphericity and few satellite powders.

[0075] Example 3: The embodiment of the present invention provides a method for preparing an antibacterial Zr-Nb alloy powder for hip joints, including:

[0076] S10 Weigh the Zr, Nb, and Cu source materials according to mass percentages.

[0077] Weigh the Zr, Nb, and Cu source materials according to Nb: 30%, Cu: 10%, Zr: 60%.

[0078] S11 Melt the Zr source material, Nb source material and Cu source material to make a casting rod, and use the casting rod as a consumable electrode for gas atomization to make powder.

[0079] Vacuum melt the Zr source material, Nb source material and Cu source material, and pour them into a casting rod after complete melting. The casting rod is flipped and remelted three times to improve the uniformity of element distribution in the prepared casting rod.

[0080] The gas atomization powder-making process is as follows: Use the prepared casting rod as a consumable electrode, and perform primary gas atomization and secondary gas atomization on the melted melt of the casting rod in a vacuum environment; the primary gas atomization uses an annular nozzle, the gas pressure is 3.0 MPa, and the outlet gas convergence angle is 25°; the secondary gas atomization uses an annular nozzle, the gas pressure is 2.2 MPa, the outlet gas convergence angle is 35°, and the temperature range of the action interval of the secondary gas atomization is 500 °C.

[0081] S12 Screen the preliminarily prepared Zr-Nb alloy powder. Through screening, Zr-Nb alloy powder with a particle size between 300 and 500 mesh is obtained.

[0082] The prepared Zr-Nb alloy powder has good sphericity and few satellite powders.

[0083] Example 4: The embodiment of the present invention provides a method for preparing a hip joint with antibacterial Zr-Nb alloy, using the Zr-Nb alloy powder prepared in Example 1, including:

[0084] S20 Obtain 3D data by CT scanning the hip joint of the patient, and perform layer slicing on the model.

[0085] S21 Import the 3D data after layer slicing into a laser 3D printing system to perform 3D printing and precision forming of the hip joint blank with Zr-Nb alloy powder; at the same time, in order to characterize the performance of the material, a metal block is prepared using the same process.

[0086] S22 Perform hot isostatic pressing and cryogenic treatment on the prepared hip joint blank.

[0087] Specifically, it includes: performing hot isostatic pressing on the prepared hip joint blank. The hot isostatic pressing process is as follows: Under the argon protection atmosphere, heat up to 1200 °C, hold for 6 h at a pressure of 120 MPa, and cool with the furnace; then cool the hip joint blank after hot isostatic pressing to -60 °C at a rate of 2 °C / min and hold for 2 h, and then place it in liquid nitrogen and hold for 5 h.

[0088] S23 Perform machining, polishing, cleaning and drying on the obtained product, and then place it in a mixed gas of nitrogen and oxygen for nitriding and oxidation treatment to obtain the hip joint.

[0089] In a mixed gas of nitrogen and oxygen, the proportion of oxygen is 5%, and the total flow rate is 60 ml / min. First, it is heated to 200 °C and maintained for 30 min, then heated to 500 °C and maintained for 5 h, and then cooled to 400 °C and maintained for 10 h.

[0090] Measure the elastic modulus and yield strength of the metal block, as Figure 3 shown. It can be seen that no cracks will occur after the block is compressed, and from Figure 4 it can be seen that there is less segregation and impurities in the prepared product, and the performance is uniform. The magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint are tested, and the results are shown in Table 1.

[0091] Example 5: The embodiment of the present invention provides a method for preparing a hip joint from an antibacterial Zr-Nb alloy, using the Zr-Nb alloy powder prepared in Example 1, including:

[0092] S20 Obtain 3D data by CT scanning the hip joint of the patient, and perform layered slicing on the model.

[0093] S21 Import the 3D data after layered slicing into a laser 3D printing system, and perform 3D printing on the Zr-Nb alloy powder to precisely form a hip joint blank.

[0094] S22 Perform hot isostatic pressing treatment and cryogenic treatment on the prepared hip joint blank.

[0095] Specifically, it includes: performing hot isostatic pressing treatment on the prepared hip joint blank. The hot isostatic pressing process is: under an argon protection atmosphere, heating to 1250 °C, maintaining at a pressure of 140 MPa for 6 h, and cooling with the furnace; then reducing the hip joint blank after hot isostatic pressing treatment to -65 °C at a rate of 3 °C / min and maintaining for 2 h, and then placing it in liquid nitrogen and maintaining for 5 h.

[0096] S23 Perform machining, polishing, cleaning, and drying on the obtained product, and then place it in a mixed gas of nitrogen and oxygen for nitriding and oxidation treatment to obtain the hip joint.

[0097] In a mixed gas of nitrogen and oxygen, the proportion of oxygen is 7%, and the total flow rate is 70 ml / min. First, it is heated to 200 °C and maintained for 40 min, then heated to 550 °C and maintained for 6 h, and then cooled to 450 °C and maintained for 10 h.

[0098] Measure the elastic modulus and yield strength of the metal block, and test the magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint. The results are shown in Table 1.

[0099] Example 6: The embodiment of the present invention provides a method for preparing a hip joint with antibacterial Zr-Nb alloy. Using the Zr-Nb alloy powder prepared in Example 1, it includes:

[0100] S20 Obtain 3D data by CT scanning the hip joint of the patient, and perform layer slicing on the model.

[0101] S21 Import the 3D data after layer slicing into a laser 3D printing system, and perform 3D printing of the Zr-Nb alloy powder to precisely form the hip joint blank.

[0102] S22 Perform hot isostatic pressing and cryogenic treatment on the prepared hip joint blank.

[0103] Specifically, it includes: performing hot isostatic pressing on the prepared hip joint blank. The hot isostatic pressing process is as follows: under an argon protection atmosphere, heat up to 1300 °C, hold for 6 h at a pressure of 160 MPa, and cool with the furnace; then cool the hip joint blank after hot isostatic pressing to -70 °C at a rate of 4 °C / min and hold for 2 h, and then place it in liquid nitrogen and hold for 5 h.

[0104] S23 Perform machining, polishing, cleaning, and drying on the obtained product, and then place it in a mixed gas of nitrogen and oxygen for nitriding and oxidation treatment to obtain the hip joint.

[0105] In the mixed gas of nitrogen and oxygen, the proportion of oxygen is 8%, the total flow rate is 80 ml / min. First, heat up to 200 °C and hold for 50 min, then heat up to 600 °C and hold for 6 h, and then cool down to 450 °C and hold for at least 10 h.

[0106] Measure the elastic modulus and yield strength of the metal block, and test the magnetic susceptibility, antibacterial performance, state of the film, and hardness of the prepared hip joint. The results are shown in Table 1.

[0107] Comparative Example 1: Different from Example 4, in the Zr-Nb alloy used in this comparative example, the Cu content is 5%.

[0108] The prepared Zr-Nb alloy powder is as Figure 5 shown, there are more satellite powders and the sphericity is poor. Compress the prepared block, as Figure 6 and 7 shown, the block is fractured; as Figure 8 , it can be concluded that when the Cu content decreases, the quality of the alloy powder is worse, the printing effect is not good, and the prepared product contains more impurities. Measure the elastic modulus and yield strength of the metal block, and test the magnetic susceptibility, antibacterial performance, state of the film, and hardness of the prepared hip joint. The results are shown in Table 1.

[0109] Comparative Example 2: Different from Example 4, in the Zr-Ni alloy used in this comparative example, the Cu content is 12.

[0110] The prepared Zr-Nb alloy powder had more satellite powders and poorer sphericity. When the prepared bulk was compressed, the bulk was fractured. The elastic modulus and yield strength of the metal bulk were measured, and the magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint were tested. The results are shown in Table 1.

[0111] Comparative Example 3: Different from Example 4, in step S11 of preparing the Zr-Nb alloy powder in this comparative example, only one atomization was used.

[0112] The elastic modulus and yield strength of the metal bulk were measured, and the results are shown in Table 1. The prepared hip joint cracked.

[0113] Comparative Example 4: Different from Example 4, in the preparation process of the hip joint in this comparative example, in the mixed gas of nitrogen and oxygen, the proportion of oxygen is 4.

[0114] The elastic modulus and compressive strength of the metal bulk were measured, and the magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint were tested. The results are shown in Table 1.

[0115] Comparative Example 5: Different from Example 4, in the preparation process of the hip joint in this comparative example, in the mixed gas of nitrogen and oxygen, the proportion of oxygen is 10%.

[0116] The elastic modulus and yield strength of the metal bulk were measured, and the magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint were tested. The results are shown in Table 1.

[0117] Comparative Example 6: Different from Example 4, in the preparation process of the hip joint in this comparative example, it was not heated to 500 °C and held for 5 h, and then cooled to 400 °C and held for 10 h.

[0118] The elastic modulus and yield strength of the metal bulk were measured, and the magnetic susceptibility, antibacterial property, state of the film, and hardness of the prepared hip joint were tested. The results are shown in Table 1.

[0119] Table 1 Performance test results of each example and comparative example

[0120]

[0121] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing antibacterial Zr-Nb alloy powder for hip joint, characterized in that: Zr-Nb alloy is composed of Zr, Nb, Cu and inevitable impurities, and by mass percentage, Nb: 25-30%, Cu: 8-10%; The preparation method comprises: Weigh the Zr source material, the Nb source material, and the Cu source material according to mass percentage, wherein the Zr source material, the Nb source material, and the Cu source material are Zr-Cu alloy, Nb-Cu alloy, and Zr metal; Smelting Zr source material, Nb source material and Cu source material to make cast rods, using the cast rods as consumable electrodes and performing gas atomization powder making; The Zr source material, the Nb source material and the Cu source material are vacuum melted and cast into cast rods after being completely melted, and the cast rods are turned over and remelted at least three times; The prepared cast rod is used as a consumable electrode, and the melt after the cast rod is melted is subjected to primary gas atomization and secondary gas atomization in a vacuum environment; The primary gas atomization adopts an annular nozzle, the gas pressure is 2.9-3.0MPa, and the gas outlet convergence angle is 22-25°; The secondary gas atomization adopts an annular nozzle, the gas pressure is 1.8-2.2MPa, the gas outlet convergence angle is 32-35°, and the temperature range of the secondary gas atomization is 400-500°C; The Zr-Nb alloy powder prepared initially is sieved to obtain; The hip joint is prepared by using Zr-Nb alloy powder obtained by sieving through laser selective melting, including the following steps: The patient's hip joint is scanned by CT to obtain 3D data, and the model is sliced ​​and processed; The 3D data after layered slicing is imported into the laser 3D printing system, and the Zr-Nb alloy powder is 3D printed to precisely form the hip joint blank; The prepared hip joint blank is subjected to hot isostatic pressing and deep cryogenic treatment. The obtained product is machined, polished, cleaned and dried, and then placed in a mixed gas of nitrogen and oxygen for nitridation and oxidation treatment to obtain the hip joint; The prepared hip joint is subjected to hot isostatic pressing and deep cryogenic treatment, including: hot isostatic pressing the prepared hip joint blank, the hot isostatic pressing process is: in an argon protective atmosphere, heating to 1200-1300° C., maintaining at a pressure of 120-160 MPa for 6 hours, and cooling with the furnace; then cooling the hip joint blank after hot isostatic pressing to -60~-70° C. at a rate of 2-4° C. / min and maintaining for at least 2 hours, and then placing in liquid nitrogen and maintaining for at least 5 hours; In the nitrogen and oxygen mixed gas, the proportion of oxygen is 5-8%, the total flow rate is 60-80ml / min, first heat up to 200 degrees Celsius and keep for 30-50 minutes, then heat up to 500-600℃ and keep for 5-6 hours, then cool down to 400-450℃ and keep for at least 10 hours.

2. The preparation method according to claim 1, characterized in that: Nb: 28%, Cu: 8%.

3. The preparation method according to claim 1, characterized in that: By sieving, Zr-Nb alloy powder with a particle size between 300-500 meshes is obtained.

4. A method for preparing a hip joint using an antibacterial Zr-Nb alloy, characterized in that: The hip joint is prepared by laser selective melting using Zr-Nb alloy powder prepared by the preparation method according to any one of claims 1 to 3; The steps include: The patient's hip joint is scanned by CT to obtain 3D data, and the model is sliced ​​and processed; The 3D data after layered slicing is imported into the laser 3D printing system, and the Zr-Nb alloy powder is 3D printed to precisely form the hip joint blank; The prepared hip joint blank is subjected to hot isostatic pressing and deep cryogenic treatment. The obtained product is machined, polished, cleaned and dried, and then placed in a mixed gas of nitrogen and oxygen for nitridation and oxidation treatment to obtain the hip joint; The prepared hip joint is subjected to hot isostatic pressing and deep cryogenic treatment, including: hot isostatic pressing the prepared hip joint blank, the hot isostatic pressing process is: in an argon protective atmosphere, heating to 1200-1300° C., maintaining at a pressure of 120-160 MPa for 6 hours, and cooling with the furnace; then cooling the hip joint blank after hot isostatic pressing to -60~-70° C. at a rate of 2-4° C. / min and maintaining for at least 2 hours, and then placing in liquid nitrogen and maintaining for at least 5 hours; In the nitrogen and oxygen mixed gas, the proportion of oxygen is 5-8%, the total flow rate is 60-80ml / min, first heat up to 200 degrees Celsius and keep for 30-50 minutes, then heat up to 500-600℃ and keep for 5-6 hours, then cool down to 400-450℃ and keep for at least 10 hours.

5. The method according to claim 4, characterized in that A body-centered cubic unit cell is used in the modeling process, and the porosity is controlled by controlling the diameter of the pillars that constitute the body-centered cube.

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