CN102796904B - A medical porous metal material replacing load-bearing bone tissue and its preparation method - Google Patents

Abstract

A medical porous metal material for replacing load-bearing bone tissue and a preparation method thereof are disclosed, wherein the medical porous metal material is prepared by mixing tantalum powder, a pore-forming agent and a forming agent, pressing the mixed powder into an organic foam body for forming, degreasing, sintering, cooling and carrying out heat treatment; the pressure adopted by the compression molding is 50-100 MPa, the temperature is gradually increased to 400-800 ℃ in the degreasing process at the speed of 0.3-2 ℃/min, argon is introduced to form a protective atmosphere, and the temperature is kept for 300-360 min; the pore-forming agent is ammonium bicarbonate or hydrogen peroxide, the forming agent is one or more of stearic acid, zinc stearate, paraffin and synthetic resin, and the formed medical porous tantalum material has the pore diameter of 100-500 mu m, the porosity of 55-65%, the elastic modulus of 3.8-4.2 GPa and the elongation of 9.3-10.7%. The preparation method of the porous tantalum provided by the invention enables the content of impurities in the final porous tantalum material to be extremely low, and simultaneously effectively solves the contradiction that the medical porous tantalum material used as a substitute bearing part requires large porosity and good mechanical property.

Description

A medical porous metal material replacing load-bearing bone tissue and its preparation method

technical field

The invention relates to a porous medical metal implant material and a preparation method thereof, in particular to a medical implant porous metal material for replacing bone tissue in a load-bearing part and a preparation method thereof.

Background technique

Porous medical metal implant materials have important and special uses in the treatment of bone tissue trauma and femoral tissue necrosis. Common materials of this type include porous metal stainless steel and porous metal titanium. As a porous implant material used in the treatment of bone tissue trauma and femoral tissue necrosis, its porosity should reach 30-80%, and the pores should be all connected and evenly distributed, or it should be consistent with the growth of human bone tissue as needed. , and reduce the weight of the material itself, so that it is suitable for human implantation.

The refractory metal tantalum/niobium, because of its excellent biocompatibility, its porous material is expected to replace the traditional medical metal biomaterials mentioned above. Because metal tantalum/niobium is harmless, non-toxic, and has no side effects to the human body, and with the rapid development of medicine at home and abroad, the understanding of tantalum/niobium as a human implant material has been further deepened, and people are more interested in porous metals for human implants. The demand for tantalum/niobium materials is becoming more and more urgent and the requirements are getting higher and higher. Among them, tantalum/niobium, as a porous medical implant metal, is expected to be used as a new type of bone tissue replacement material if it can have high uniformly distributed interconnected pores and physical and mechanical properties compatible with the human body.

The porous metal material used as a medical implant is basically based on the powder sintering method as the general porous metal material, especially in order to obtain a porous metal foam structure with pore connectivity and uniform distribution. The impregnation of powder slurry on organic foam, drying and sintering is mostly referred to as foam impregnation method. The mechanical properties of porous metal materials obtained by powder sintering are usually not very good. The main reason is how to arrange the support and elimination relationship of the pore-forming medium in the process, and the collapse problem during the sintering process of metal powder. However, in the known literature reports, there is no good solution and let nature go.

There are few literature reports on the production of porous tantalum/niobium by metal powder sintering method, especially there are almost no literature reports on the porous tantalum/niobium powder sintering method for the purpose of obtaining medical implant materials. Reference can be made to the publication numbers CN200510032174, titled “Porous Metal Foam with Three-Dimensional Through Holes or Partial Holes Connected to Each Other and Its Preparation Method” and CN200710152394, titled “A Novel Porous Tungsten Foam and Its Preparation Method”. However, the obtained porous metal is either used as a filter material, or used in aerospace and other high-temperature applications rather than as a medical metal implant material, and the processed porous metal is not porous tantalum/niobium.

Regarding porous tantalum, US5282861 discloses a porous tantalum material applied to cancellous bone implants, cells and tissue receptors and its preparation. This kind of porous tantalum is made of pure commercial tantalum. It uses the carbon skeleton obtained by the thermal degradation of the polyurethane precursor as the support. Pores, the porosity can be as high as 98%, and then the commercial pure tantalum is combined with the carbon skeleton by chemical vapor deposition and infiltration to form a porous metal microstructure, which is referred to as the chemical deposition method. The thickness of the tantalum layer on the surface of the porous tantalum material obtained by this method is between 40 and 60 μm; in the entire porous material, the weight of tantalum accounts for about 99%, while the weight of carbon skeleton accounts for about 1%. The literature further records that the compressive strength of the porous material is 50-70 MPa, the modulus of elasticity is 2.5-3.5 GPa, and the tensile strength is 63 MPa. However, when it is used as a substitute for porous tantalum for medical implant materials such as the skull, the mechanical properties of the material, such as ductility, are obviously insufficient, which will affect the subsequent processing of the porous tantalum material itself, such as molding parts. cutting etc. Also all there is such deficiency in the product that aforementioned metal powder sintering method obtains. Due to the limitation of its preparation method, the purity of the obtained finished product is not enough, and there are carbon skeleton residues, resulting in a decrease in biological safety.

Contents of the invention

The purpose of the present invention is to provide a medical porous metal material with high product purity and suitable for replacing load-bearing bone tissue.

Another object of the present invention is to provide a preparation method of the above-mentioned medical porous metal material.

The purpose of the present invention is achieved by the following technical means:

A medical porous metal material that replaces load-bearing bone tissue is characterized in that it is made of tantalum powder mixed with pore-forming agent and forming agent, and then press-molded, degreased, sintered, cooled and heat-treated; the press-molded The mixed powder is pressed into an organic foam with a pressure of 50-100Mpa, and the degreasing process is to gradually raise the temperature to 400-800°C at a rate of 0.3°C/min-2°C/min, and the composition is formed by feeding in argon gas. Protect the atmosphere and keep warm for 300min to 360min; the pore-forming agent is ammonium bicarbonate or hydrogen peroxide, and the forming agent is stearic acid, zinc stearate, paraffin, synthetic resin (preferably styrene-butadiene rubber or isoprene rubber) One or more of them, the pore diameter of the formed medical porous tantalum material is 100-500 μm, the porosity is 55-65%, the elastic modulus is 3.8-4.2 Gpa, and the elongation is 9.3-10.7%.

In the research and development process of medical porous metal materials, medical porous metal materials are required to replace load-bearing bone tissue, so that their porosity is relatively large, so that human tissues can easily grow into them, and they have good biocompatibility to fully play their role. The larger the porosity and the larger the pore diameter, the mechanical properties such as strength and toughness cannot be guaranteed; on the contrary, if the mechanical properties are good, the porosity is too small, the biocompatibility is not good, and the density is too large to cause discomfort. ; There are many preparation routes for medical porous tantalum, but the inventor creatively proposes to adopt the above steps and process to prepare medical porous tantalum implant material, which effectively prevents the easy plugging of holes and the difficult control of the dipping process by using the dipping method, and makes problems such as uneven product quality; the prepared porous tantalum material has been tested and its impurity content can be lower than 0.2%. It has good biocompatibility and biosafety, and its density can reach 5.83-7.50g/cm ³ . It can reach 55-65%, the pore diameter can reach 100-500μm; the elastic modulus can reach 3.8-4.2Gpa, the elongation can reach 9.3-10.7%, the bending strength can reach 100-120Mpa, and the compressive strength can reach 60-70Mpa. It has excellent biocompatibility, strength and toughness, and is close to the load-bearing bone tissue of the human body. The porous tantalum of the present invention is very suitable for being used as a medical implant material for replacing the load-bearing bone tissue.

The raw tantalum powder used in the present invention has an average particle size of less than 43 microns and an oxygen content of less than 0.1%, which is a commercially available product; the above-mentioned pore-forming agent and forming agent are also commercially available. The vacuum environment of the present invention preferably adopts a vacuum condition with a degree of vacuum ranging from 10 ^-4 Pa to 10 ^-3 Pa. The above-mentioned organic foam is preferably polyurethane foam, more preferably a pore size of 0.48-0.89 mm, a density of 0.015 g/cm ³ to 0.035 g/cm ³ , and a hardness greater than 50° (most preferably a pore size of 0.56-0.72 mm and a density of 0.025 g/cm ³ , Hardness 50°～80°) in polyurethane foam.

During the research and development process, the inventor further researched and found that if the above-mentioned preparation is not well controlled, although the above-mentioned medical implant material suitable for replacing load-bearing bone tissue can be produced, the product quality stability is not ideal, and the pass rate is not high: For example, the powder is difficult to form, and the parts after pressing are prone to delamination and unevenness, and the parts after degreasing will have cracks and other technical problems.

In order to make molding easier during the powder compaction process, thereby improving the yield of finished products, the uniformity of finished product pores, and making the preparation process more stable, the amount of the above-mentioned pore-forming agent is 15-25%, the amount of molding agent is 7-12%, and the balance It is tantalum powder, all in volume percentage (volume percentage is a unit directly calculated by the situation of the final porous tantalum material, and the solid powder is still based on the weight of the corresponding substance in the weighing of the above-mentioned pore-forming agent and molding agent. Density is calculated by its corresponding mass weighing (certainly if it is a liquid substance then directly adopts volume weighing), further preferably the pore-forming agent is hydrogen peroxide and accounts for 18%, the forming agent is zinc stearate and accounts for 11%, and the balance is Tantalum powder, calculated by volume percentage; the pressure during the above-mentioned compression molding process is preferably 75-87Mpa.

In order to make the embryo body more stable during the degreasing process, reduce the prone part of the embryo body deformation and uneven pore size, so as to further improve the yield and quality stability, the above degreasing process is carried out step by step at a rate of 0.3°C/min～1°C/min Raise the temperature to 400-800°C, pass in argon gas to form a protective atmosphere and keep it warm for 330min-350min; further preferably, gradually raise the temperature to 400-800°C at a rate of 0.8°C/min, pass in argon gas to form a protective atmosphere and keep warm for 340min.

A preparation method of a medical porous metal material that replaces load-bearing bone tissue, which is sintered by molding method, and is characterized in that tantalum powder is mixed with a pore-forming agent and a forming agent, and then the mixed powder is pressed at 50-100Mpa Forming into organic foam, degreasing, sintering, cooling and heat treatment to obtain a medical porous metal material that replaces the load-bearing bone tissue; the pore-forming agent is ammonium bicarbonate or hydrogen peroxide, and the forming agent is stearic acid, stearic acid One or more of zinc, paraffin, synthetic resin (preferably styrene-butadiene rubber or isoprene rubber), wherein the amount of pore-forming agent is 15-25%, the amount of molding agent is 7-12%, and the balance is Tantalum powder, all in volume percentage; the degreasing process is to gradually raise the temperature to 400-800°C at a rate of 0.3°C/min-2°C/min, and argon gas is introduced to form a protective atmosphere and kept for 300min-360min.

The average particle size of the above-mentioned raw material tantalum powder is less than 43 microns, and the oxygen content is less than 0.1%. The above-mentioned pore-forming agent is further preferably hydrogen peroxide accounting for 18%, the molding agent is zinc stearate accounting for 11%, and the balance is tantalum powder. content meter. The above-mentioned organic foam is preferably polyurethane foam, more preferably a pore size of 0.48-0.89 mm, a density of 0.015 g/cm ³ to 0.035 g/cm ³ , and a hardness greater than 50° (most preferably a pore size of 0.56-0.72 mm and a density of 0.025 g/cm ³ , Hardness 50°～80°) in polyurethane foam.

In order to make the pressing pressure uniform and not delaminated during the pressing embryo making process, so that the final porous tantalum pore distribution is more uniform and the quality is more stable, the pressure used in the above pressing process is preferably 75 ~ 87Mpa, and the pressure used in the above degreasing process is preferably 0.3 The temperature is gradually raised to 400-800°C at a rate of ℃/min-1°C/min, and the protective atmosphere is formed by introducing argon gas and kept for 330-350 minutes. Argon gas was introduced to form a protective atmosphere and kept for 340min.

A further feature of another aspect of the present invention is that the porous sintered body is prepared by vacuum sintering at a vacuum degree of not less than 10 ^-4 ~ 10 ^-3 Pa, a temperature of 2000 ~ 2200 ° C, and a holding time of 1 ~ 5 hours. During the sintering process, it can be filled with inert gas protection instead of vacuum protection; finally, vacuum annealing treatment is carried out. The vacuum annealing treatment refers to continuing to maintain the temperature at 1000-1250 °C after vacuum sintering, the holding time is 1-4 hours, and the vacuum degree is not lower than 10 ^-4 ~ 10 ^-3 Pa.

Vacuum sintering conditions also include: the degree of vacuum is not lower than 10 ^-3 Pa, the temperature rises from room temperature to 1200 ° C ~ 1500 ° C at a rate of 10 ~ 20 ° C / min, and after holding for 1 h ~ 2 h; /min heating rate to 2000 ~ 2200 ℃, at least 2h ~ 4h.

The cooling conditions after vacuum sintering also include: the vacuum degree is not lower than 10 ^-3 Pa, and the sintered porous body is cooled in stages with a gradual cooling rate of not higher than 25°C/min and not lower than 10°C/min To 800°C, the holding time of each section is 30min to 90min, and then cool down to room temperature with the furnace.

Vacuum annealing conditions also include: vacuum degree not lower than 10 ^-4 Pa, rising to 1000~1250℃ at a rate not higher than 30℃/min, holding for 4h~6h; °C/min but not higher than 30 °C/min cooling rate to room temperature in sections, the holding time of each section is decreasing and selected within 1.5h to 3h.

A further feature on this basis is: the degreasing treatment conditions also include: rising from room temperature to 400°C at a rate of 1-2°C/min, keeping the temperature for 300-330min, and heating at a rate of 0.3-0.8°C/min Raise from 400°C to 600-800°C, keep warm for 340-360min; the vacuum sintering conditions also include: rise from room temperature to 1200-1250°C at a rate of 10-15°C/min, keep warm for 30-60min, vacuum 10 ^-4 Pa ~ 10 ^-3 Pa, rise to 1500°C at a rate of 10 ~ 20°C/min, keep warm for 30 ~ 60min, and vacuum degree is 10 ^-4 Pa ~ 10 ^-3 Pa, at a rate of 6 ~ 20°C/min The temperature rises to 2000～2200℃, the heat preservation time is 120～240min, and the vacuum degree is 10 ^-4 Pa～10 ^-3 Pa; the cooling conditions after vacuum sintering also include: the vacuum degree is 10 ^-4 Pa～10 ^-3 Pa; Cool at a rate of 10-20°C/min to 1500-1600°C, keep warm for 30-60min; cool at a rate of 12-20°C/min to 1200-1250°C, keep warm for 60-90min; Cooling at a rate of 800°C, and then cooling with the furnace; the vacuum annealing conditions also include: rising to 1000-1250°C at a rate of 15-30°C/min, holding for 240-480min, and a vacuum degree of 10 ^-4 Pa-10 ^-3 Pa, then cool to 1000°C at a rate of 5-10°C/min, hold for 90-180min, vacuum degree is ^10-4 Pa- ^10-3 Pa; cool to 800°C at a rate of 10-20°C/min , keep warm for 60-120 min, and the vacuum degree is 10 ^-4 Pa; cool to room temperature at a rate of 20-30°C/min, and the vacuum degree is 10 ^-4 Pa-10 ^-3 Pa.

The properties of metal tantalum and niobium are very similar, and the above method is also suitable for the preparation of medical porous niobium materials.

The preparation method of the porous tantalum of the present invention adopts a purely physical molding method, so that the content of impurities in the final porous tantalum material is extremely low, and the biocompatibility and biosafety are effectively improved; The optimization of process conditions leads to high yield, better pore size uniformity, more stable preparation process, good quality stability, effectively eliminates thermal stress, and makes the structure of porous tantalum material more uniform, so as to further improve the mechanical properties of porous tantalum. Properties such as strength and toughness are improved at the same time, and the preparation process of the invention leads to a high qualified rate of finished products and stable production, and the qualified rate of products can be as high as 92%. The porous tantalum finished product prepared by the present invention has uniform and connected pores, good biocompatibility, and after testing, its impurity content can be lower than 0.2%, its density can reach 5.83-7.50g/cm ³ , and its porosity can reach 55-65%. , the pore diameter can reach 100-500μm; the elastic modulus can reach 3.8-4.2Gpa, the elongation can reach 9.3-10.7%, the bending strength can reach 100-120Mpa, and the compressive strength can reach 60-70Mpa, which effectively solves the problem of being an alternative load-bearing The medical porous tantalum material in the site requires both its large porosity and good mechanical properties. The porous tantalum of the present invention is very suitable for use as a medical implant material to replace the load-bearing bone tissue.

Detailed ways

The present invention is specifically described below through the examples, it is necessary to point out that the following examples are only used to further illustrate the present invention, and can not be interpreted as limiting the protection scope of the present invention, those skilled in the art can according to the above-mentioned present invention Contents Some non-essential improvements and adjustments are made to the present invention.

A medical porous tantalum material that replaces the load-bearing bone tissue specifically selects one or more of stearic acid, zinc stearate, paraffin, and synthetic rubber as a forming agent, and ammonium bicarbonate or hydrogen peroxide as a pore-forming agent. It is obtained by mixing tantalum powder with a particle size of less than 43 microns and an oxygen content of less than 0.1%, pressing the mixed powder into an organic foam body at 50-100 MPa, and then undergoing degreasing, sintering, cooling and heat treatment; the degreasing process The temperature is gradually raised to 400-800°C at a rate of 0.3°C/min-2°C/min, and argon gas is introduced to form a protective atmosphere and kept for 300min-360min. The formed medical porous tantalum material has a pore diameter of 100-500 μm, a porosity of 55-65%, an elastic modulus of 3.8-4.2 Gpa, and an elongation of 9.3-10.7%.

More specifically, the above-mentioned porous tantalum is composed of 7-12% (by volume percentage) of the above-mentioned forming agent, 15-25% (by volume percentage) of the above-mentioned pore-forming agent and the balance of tantalum powder Mix it, put it into an injection molding machine and pressurize it into a polyurethane foam to form; then put it in a tungsten vessel, put pure argon gas (99.9999%) into the protective atmosphere furnace, and gradually heat up to a certain temperature, and Heat preservation and degreasing treatment to remove pore-forming agent, forming agent and polyurethane foam, in which argon gas is introduced to remove the air in the furnace before heating up, and the degreasing sample is cooled with the furnace; The temperature in the high-vacuum high-temperature sintering furnace is gradually raised to 2000-2200°C, and the holding time is 1-5 hours for vacuum sintering. Before the temperature rises, the vacuum degree of the sintering furnace must reach at least an appropriate level. Maintain a certain degree of vacuum or cool in sections at a certain cooling rate to maintain a certain temperature for an appropriate time. During the heat preservation process, an inert gas can be used as a protective atmosphere. For the samples after vacuum sintering and cooling, the corundum container is placed in the vacuum annealing furnace to gradually heat up and keep warm for stress relief annealing treatment. Before the temperature rises, a certain degree of vacuum is maintained in the annealing furnace. During the process, maintain a certain degree of vacuum or cool in sections at a certain cooling rate to maintain a certain temperature for an appropriate time. During the heat preservation process, you can use an inert gas as a protective atmosphere, and finally perform conventional post-treatment to produce porous tantalum.

For the degreasing process, the degreasing process is to gradually increase the temperature to 400-800°C at a rate of 0.3°C/min-1°C/min, and use argon gas to form a protective atmosphere and keep it warm for 330min-350min; more preferably at a rate of 0.8°C/min Gradually raise the temperature to 400-800°C, pass in argon gas to form a protective atmosphere and keep it warm for 340min. Vacuum sintering of the degreasing sample is to place it in a high-vacuum high-temperature sintering furnace with a tungsten vessel at a certain heating rate to the highest sintering temperature of tantalum for vacuum sintering, and the sintering furnace maintains a certain vacuum before heating up. temperature at a certain heating rate to, for example, 1200°C to 1250°C, keep the heat, and keep the vacuum; at a certain heating rate, raise the temperature to, for example, 1250°C to 1500°C, keep warm, and then at a certain heating rate to the highest temperature such as tantalum Sintering temperature, keep warm, keep vacuum; after sintering, keep vacuum, cool at a certain cooling rate to, for example, 1500°C to 1600°C, keep warm, then cool at a certain cooling rate to, for example, 1200°C to 1250°C, keep warm, and keep at a certain temperature The cooling rate is cooled to, for example, 800 ° C, and then cooled with the furnace. Vacuum annealing is carried out on the sample after vacuum sintering and cooling, which is to place it in a vacuum annealing furnace with the corundum container at a certain heating rate to, for example, 1000 ° C ~ 1250 ° C for stress relief annealing. Keep the vacuum, raise the temperature from room temperature to 1000 ℃ ~ 1250 ℃ at a certain heating rate, keep the heat, keep the vacuum; then cool to 1000 ℃ at a certain cooling rate, keep the temperature; then cool to 800 ℃ at a certain cooling rate , keep warm; also cool the room temperature at a certain cooling rate. Finally, conventional post-treatment is carried out to produce porous tantalum.

The inventor adopts the metal powder sintering method mainly based on the physical molding method, and has done a lot of theoretical analysis and experimental verification. After testing, the impurity content of the porous tantalum product can be lower than 0.2%, and the density can reach 5.83-7.50g/cm ³ , the porosity can reach 55-65%, the pore diameter can reach 100-500μm; the elastic modulus can reach 3.8-4.2Gpa, the elongation can reach 9.3-10.7%, the bending strength can reach 100-120Mpa, and the compressive strength can reach 60 ~70Mpa.

Embodiment 1: Weigh zinc stearate, average particle diameter is less than 43 micron oxygen content is less than 0.1% tantalum powder and hydrogen peroxide mix uniformly, wherein zinc stearate accounts for 11%, hydrogen peroxide accounts for 18%, tantalum powder accounts for 71%, All are calculated by volume percentage. Compression molding: Add the above mixed powder into an injection molding machine and press it into a polyurethane foam (pore diameter 0.48-0.89mm, density 0.015g/cm ³ -0.035g/cm ³ , hardness greater than 50°) at 82Mpa to form. Degreasing treatment: vacuum degree 10 ^-4 Pa, heating from room temperature to 400°C at a heating rate of 2.0°C/min, and holding for 320 minutes; then raising the temperature from 400°C to 700°C at a heating rate of 0.5°C/min, holding for 350 minutes. Vacuum sintering: sintering in a vacuum furnace, sintering temperature 2000 ° C, heat preservation for 2 hours, vacuum degree 10 ^-4 Pa, argon protection during the sintering process, remove surface dust and dirt after taking out the product, and then carry out conventional Post-processing the finished porous tantalum.

According to the standards of GB/T5163-2006, GB/T5249-1985, GB/T6886-2001, etc., the inventor tested the porous material density, porosity, pore diameter and various mechanical properties of the above-mentioned porous tantalum products: the impurity content is less than 0.2 %, its pores are evenly distributed, with a density of 6.24g/cm ³ , a porosity of 60%, an average pore diameter of 200μm, an elastic modulus of 4.0Gpa, an elongation of 10.02%, a bending strength of 115MPa, and a compressive strength of 66MPa.

Embodiment 2: Weigh stearic acid, tantalum powder and ammonium bicarbonate with an average particle size less than 43 microns and an oxygen content of less than 0.1% and mix evenly, wherein stearic acid accounts for 7%, ammonium bicarbonate accounts for 25%, and tantalum powder accounts for 68% %, all in volume percentage. Compression molding: Add the above mixed powder into an injection molding machine and press it into a polyurethane foam (pore diameter 0.48-0.89mm, density 0.015g/cm ³ -0.035g/cm ³ , hardness greater than 50°) at 87Mpa. Degreasing treatment: the degree of vacuum is 10 ^-4 Pa, the temperature is raised from room temperature to 400°C at a heating rate of 2°C/min, and the temperature is kept for 300min. Vacuum sintering: sintering in a vacuum furnace, sintering temperature 2100 ° C, heat preservation for 4 hours, vacuum degree 10 ^-4 Pa, argon protection during the sintering process, remove surface dust and dirt after taking out the product, and then carry out conventional After processing the finished porous tantalum.

According to the standards of GB/T5163-2006, GB/T5249-1985, GB/T6886-2001, etc., the inventor tested the porous material density, porosity, pore diameter and various mechanical properties of the above-mentioned porous tantalum products: the impurity content is less than 0.2 %, its pores are uniformly distributed, with a density of 6.05g/cm ³ , a porosity of 65%, an average pore diameter of 400μm, an elastic modulus of 3.8Gpa, an elongation of 9.5%, a bending strength of 100MPa, and a compressive strength of 60MPa.

Embodiment 3: Weigh styrene-butadiene rubber, tantalum powder with an average particle diameter of less than 43 microns and an oxygen content of less than 0.1%, and mix evenly with hydrogen peroxide, wherein styrene-butadiene rubber accounts for 12%, hydrogen peroxide accounts for 15%, and tantalum powder accounts for 73%, all with Volume percentage meter. Compression molding: Add the above mixed powder into an injection molding machine and press it into a polyurethane foam (pore diameter 0.48-0.89mm, density 0.015g/cm ³ -0.035g/cm ³ , hardness greater than 50°) at 52Mpa to form. Degreasing treatment: the degree of vacuum is 10 ^-4 Pa, the temperature is raised from room temperature to 400°C at a heating rate of 0.3°C/min, and the temperature is kept for 360min. Vacuum sintering: sintering in a vacuum furnace, sintering temperature 2200°C, heat preservation 2.5 hours, vacuum degree 10 ^-3 Pa, fill the sintering process with argon protection, cool out of the furnace, remove dust and dirt on the surface of the product, and then conduct conventional Post-processing of the porous tantalum finish.

According to the standards of GB/T5163-2006, GB/T5249-1985, GB/T6886-2001, etc., the inventor tested the porous material density, porosity, pore diameter and various mechanical properties of the above-mentioned porous tantalum products: the impurity content is less than 0.2 %, its pores are uniformly distributed, with a density of 6.31g/cm ³ , a porosity of 55%, an average pore diameter of 100μm, an elastic modulus of 3.9Gpa, an elongation of 9.3%, a bending strength of 105MPa, and a compressive strength of 63MPa.

Embodiment 4: take by weighing paraffin, the niobium powder and ammonium bicarbonate that average particle diameter is less than 43 microns and oxygen content are less than 0.1% mix evenly, wherein paraffin accounts for 10%, ammonium bicarbonate accounts for 20%, niobium powder accounts for 70%, all with Volume percentage meter. Compression molding: Add the above mixed powder into an injection molding machine and press it into a polyurethane foam (pore diameter 0.48-0.89mm, density 0.015g/cm ³ -0.035g/cm ³ , hardness greater than 50°) at 96Mpa to form. Degreasing treatment: the degree of vacuum is 10 ^-4 Pa, the temperature is raised from room temperature to 400°C at a heating rate of 0.8°C/min, and the temperature is kept for 340min. Vacuum sintering: sintering in a vacuum furnace, sintering temperature 2150°C, heat preservation for 2 hours, vacuum degree 10 ^-4 Pa, argon protection during the sintering process, cooling out of the furnace, removing dust and dirt on the surface of the product, and the prepared samples are then subjected to routine Post-processing of the porous niobium finished product.

The inventor tested the porous material density, porosity, pore diameter and various mechanical properties of the above-mentioned porous niobium finished products according to standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: the impurity content is lower than 0.2 %, its pores are uniformly distributed, with a density of 3.77g/cm ³ , a porosity of 56%, an average pore diameter of 108μm, an elastic modulus of 3.0Gpa, an elongation of 9.8%, a bending strength of 67MPa, and a compressive strength of 54MPa.

Embodiment 5: A kind of porous tantalum, it is raw material with particle diameter less than 43 μ m, the metal tantalum powder of oxygen content less than 0.1%, the mixed powder of stearic acid and hydrogen peroxide, then through compression molding, degreasing treatment, vacuum sintering, vacuum annealing and Produced by conventional post-processing.

Among them, stearic acid accounts for 11%, hydrogen peroxide accounts for 22%, metal tantalum powder accounts for 67%, calculated by volume percentage;

Compression molding: Add the mixed powder of raw materials into the injection molding machine and press it into polyurethane foam (pore diameter 0.48-0.89mm, density 0.015g/cm ³ ～0.035g/cm ³ , hardness greater than 50°) at 78Mpa to form;

After pressing and molding, put the mixed powder into a non-oxidizing atmosphere furnace and raise the temperature to 800°C at a certain heating rate. The protective atmosphere is 99.999% argon for degreasing treatment. Before heating up, let pure argon gas flow for at least 30 minutes to get rid of the furnace. Air, temperature control process: rise from room temperature to 400°C at a rate of 1.5°C/min, keep warm for 300min, and argon gas flow rate is 0.5L/min; rise from 400°C to 800°C at a rate of 0.6°C/min, keep warm 340min, the argon flow rate is 1/L/min; then turn off the power, the degreased sample is cooled with the furnace, the argon flow rate is 1L/min, and the argon gas is turned off when it cools to room temperature;

For the samples after degreasing treatment, they are placed in a high-vacuum high-temperature sintering furnace with a tungsten device and heated to 2200°C at a certain heating rate for vacuum sintering. Before the temperature rises, the vacuum degree of the sintering furnace must reach at least 10 ^-4 Pa. Raise from room temperature to 1200°C at the rate of ℃/min, hold for 30 minutes, and the vacuum degree is 10 ^-4 Pa; rise to 1500°C at the rate of 10°C/min, hold for 30 minutes, and the vacuum degree is 10 ^-4 Pa to 10 ^-3 Pa; rise to 2200°C at a rate of 6°C/min, hold for 120min, and vacuum degree is 10 ^-3 Pa; after sintering, the vacuum degree is 10 ^-3 Pa, cool to 1600°C at a rate of 10-15°C/min, Hold for 30 minutes; cool to 1200°C at a rate of 12°C/min, hold for 60 minutes; cool to 800°C at a rate of 10°C/min, and then cool with the furnace;

For the samples after vacuum sintering and cooling, put the corundum container in the vacuum annealing furnace and raise the temperature to ¹²⁵⁰ °C at a certain heating rate for stress relief annealing treatment. Rise from room temperature to 1250°C at the rate of ℃/min, hold for 240min, and the vacuum degree is 10 ^-4 Pa to 10 ^-3 Pa; then cool to 1000°C at the rate of 5°C/min, hold for 180min, and the vacuum degree is 10 ^{- 4} Pa to 10 ^-3 Pa; cool to 800°C at a rate of 10°C/min, hold for 120min, and a vacuum of 10 ^-4 Pa; cool to room temperature at a rate of 20°C/min, and a vacuum of 10 ^-4 Pa. Finally, conventional post-treatment is carried out to produce porous tantalum.

According to the standards of GB/T5163-2006, GB/T5249-1985, GB/T6886-2001, etc., the inventor tested the porous material density, porosity, pore diameter and various mechanical properties of the above-mentioned porous tantalum products: the impurity content is less than 0.2 %, its pores are evenly distributed, with a density of 6.8g/cm ³ , a porosity of 62%, an average pore diameter of 250μm, an elastic modulus of 4.15Gpa, an elongation of 10.32%, a bending strength of 118MPa, and a compressive strength of 65MPa. The pass rate of the products of this preparation process is calculated to reach 90.3%.

In the method given in the above-mentioned Example 5, we can also make other choices for the various conditions therein to obtain the porous tantalum or porous niobium of the present invention as well.

The resulting porous tantalum or porous niobium finished product is tested by the aforementioned method:

Example 6 7 8 Density (g/cm ³ ) 6.3 3.3 7.0 Porosity(%) 56 63 60 Pore diameter (μm) 150 260 390 Elastic modulus (GPa) 3.9 2.1 4.2 Elongation (%) 9.8 10.03 9.4 Bending strength (MPa) 120 79 109 Compressive strength (MPa) 63 55 68

Claims (10)

1. the medical porous metal material of an alternative load-bearing bone tissue is characterized in that: by the tantalum powder, with pore creating material, forming agent, mixed, more repressed molding, defat, sintering, cooling and heat treatment makes; Described compressing be that described mixed-powder is pressed into to molding in Organic Foam Material, compressing pressure is 50～100MPa, described skimming processes is that the speed with 0.3 ℃/min～2 ℃/min progressively is warming up to 400～800 ℃, with argon, passes into and forms protective atmosphere and be incubated 300min～360min; Described pore creating material is ammonium bicarbonate or hydrogen peroxide, described forming agent is one or more in stearic acid, zinc stearate, paraffin, synthetic resin, and the medical porous tantalum material pore diameter of formation is 100～500 μ m, porosity between 55～65%, elastic modelling quantity is that 3.8～4.2GPa, percentage elongation are 9.3～10.7%.

2. medical porous metal material as claimed in claim 1 is characterized in that: the mean diameter of Ta powder is less than 43 microns, oxygen content and is less than 0.1%; Described synthetic resin is butadiene-styrene rubber or isoprene rubber; Described Organic Foam Material is aperture 0.56～0.72mm, density 0.025g/cm ³, hardness 50 ⁰～80 ⁰polyurethane foam.

3. medical porous metal material as claimed in claim 1 or 2 is characterized in that: the consumption of described pore creating material is 15～25%, the consumption of described forming agent is 7～12%, surplus is the tantalum powder, all in volumn concentration; Pressure in described compressing process is 75～87MPa.

4. medical porous metal material as claimed in claim 3 is characterized in that: described pore creating material is that hydrogen peroxide accounts for 18%, described forming agent is that zinc stearate accounts for 11%, surplus is the tantalum powder, in volumn concentration.

5. medical porous metal material as claimed in claim 1 is characterized in that: described skimming processes is that the speed with 0.3 ℃/min～1 ℃/min progressively is warming up to 400～800 ℃, with argon, passes into and forms protective atmosphere and be incubated 330min～350min.

6. the preparation method of the medical porous metal material of an alternative load-bearing bone tissue as claimed in claim 1, adopt the die pressing sintering to form, its characteristics are: the tantalum powder is mixed with pore creating material, forming agent, then to be pressed into aperture under 50～100MPa be 0.56～0.72mm density 0.025g/cm ³, hardness 50 ⁰～80 ⁰polyurethane foam in molding, defat, sintering, cooling and heat treatment make the medical porous metal material that substitutes the load-bearing bone tissue; Described pore creating material is ammonium bicarbonate or hydrogen peroxide, described forming agent is one or more in stearic acid, zinc stearate, paraffin, synthetic resin, the consumption of described pore creating material is 15～25%, the consumption of described forming agent is 7～12%, surplus is the tantalum powder, all in volumn concentration; Described skimming processes is that the speed with 0.3 ℃/min～2 ℃/min progressively is warming up to 400～800 ℃, with argon, passes into and forms protective atmosphere and be incubated 300min～360min.

7. preparation method as claimed in claim 6 is characterized in that: the mean diameter of Ta powder is less than 43 microns, oxygen content and is less than 0.1%; Described pore creating material is that hydrogen peroxide accounts for 18%, described forming agent is that zinc stearate accounts for 11%, surplus is the tantalum powder, in volumn concentration; The pressure adopted in described pressing process is 75～87MPa.

8. preparation method as claimed in claim 7 is characterized in that: the speed with 0.3 ℃/min～1 ℃/min in described skimming processes progressively is warming up to 400～800 ℃, with argon, passes into and forms protective atmosphere and be incubated 330min～350min.

9. preparation method as claimed in claim 8, it is characterized in that: the speed with 0.8 ℃/min in described skimming processes progressively is warming up to 400～800 ℃, with argon, passes into and forms protective atmosphere and be incubated 340min.

10. preparation method as described as claim 6 or 7, it is characterized in that: described vacuum-sintering condition is: the speed with 10～15 ℃/min rises to 1200～1250 ℃ from room temperature, is incubated 30～60min, and vacuum is 10 ^-4pa～10 ^-3pa, rise to 1500 ℃ with the speed of 10～20 ℃/min, is incubated 30～60min, and vacuum is 10 ^-4pa～10 ^-3pa, rise to 2000～2200 ℃ with the speed of 6～20 ℃/min, is incubated 120～240min, and vacuum is 10 ^-4pa～10 ^-3pa; Cooling condition after vacuum-sintering is: vacuum is 10 ^-4pa～10 ^-3pa; Speed with 10～20 ℃/min is cooled to 1500～1600 ℃, is incubated 30～60min; Speed with 12～20 ℃/min is cooled to 1200～1250 ℃, is incubated 60～90min; Speed with 10～20 ℃/min is cooled to 800 ℃, then furnace cooling; The vacuum annealing heat-treat condition is: the speed with 15～30 ℃/min rises to 1000～1250 ℃, is incubated 240～480min, and vacuum is 10 ^-4pa～10 ^-3pa, then be cooled to 1000 ℃ with the speed of 5～10 ℃/min, being incubated 90～180min, vacuum is 10 ^-4pa～10 ^-3pa; Speed with 10～20 ℃/min is cooled to 800 ℃, is incubated 60～120min, and vacuum is 10 ^-4pa; Speed with 20～30 ℃/min is cooled to room temperature, and vacuum is 10 ^-4pa～10 ^-3pa.