A kind of method of preparing medical porous tantalum embedded material
Technical field
The present invention relates to a kind of porous medical metal implanted material, particularly relate to a kind of preparation method that is suitable for the medical porous tantalum embedded material of alternative load-bearing bone tissue.
Background technology
Porous medical metal implanted material has the important and special purposes such as treatment osseous tissue wound and bone formation necrosis, and existing this common class material has porous metals rustless steel, porous metals titanium etc.Porous embedded material as osseous tissue wound and the use of bone formation necrosis therapeutic, its porosity should reach 30~80%, and hole is preferably all communicated with and is uniformly distributed, or hole is partly communicated with and is uniformly distributed as required, make it both consistent with the bone growth of human body, alleviate again the weight of material itself, to be applicable to human body, implanted use.
And refractory metals tantalum, because it has outstanding biocompatibility and mechanical property, its porous material is expected to the conventional medical metallic biomaterial such as aforementioned as an alternative, becomes the biomaterial mainly as bone necrosis's treatment.Due to metal tantalum to human body harmless, nontoxic, have no side effect, and along with the develop rapidly of domestic and international medical science, tantalum is goed deep into as the further of body implanting material cognition, and people implant and become more and more urgent by the demand of porous metals tantalum material human body, also more and more higher to its requirement., as the medical embedded metal tantalum of porous, if can there is the very high physical and mechanical properties that is uniformly distributed interconnected pore and adapts with human body, be wherein the heavy connection constituent material that guarantees freshman bone tissue's normal growth.
As medical embedded porous metal material just as porous metal material be to take powder sintering as main processing method like that substantially, in particular for obtain porosity communication and equally distributed porous metal foam structure adopt metal dust slurry in the powder sintering dipping on Organic Foam Material afterwards the dry knot that reburns to be called for short foam impregnation method in the majority.About powder sintered obtained porosity communication and equally distributed porous metal material conventionally its Metal Mechanic Property be not fine, its main cause is the problem of subsiding how arranging in technique in the support of pore-forming medium and elimination relation, metal powder sintered process.And in known bibliographical information, all there is no good solution and laissez-faire nature.
Adopt bibliographical information that metal powder sintered legal system makes porous tantalum seldom, particularly take and obtain medical embedded material and almost do not have with the porous tantalum powder sintering bibliographical information that is object.Can reference be that publication number is CN200510032174, title " three-dimensional through hole or part hole porous metal foam connected with each other and preparation method thereof " and CN200710152394, title " a kind of porous foam tungsten and preparation method thereof ".Yet porous metals that it obtains or for filtering material use, or share for Aero-Space and other high-temperature field but not use as medical metal implanted material, moreover also non-porous tantalum of the porous metals of processing.
About porous tantalum, US5282861 discloses a kind of perforate tantalum material and preparation thereof that is applied to spongy bone implant, cell and organizes sensor.This porous tantalum is made by pure business tantalum, it take polyurethane precursor, and to carry out the carbon skeleton that thermal degradation obtains be support, this carbon skeleton is multiple dodecahedron, it in it, is mesh-like structure, integral body spreads all over micropore, porosity can be up to 98%, then the method by chemical vapour deposition, infiltration is attached on carbon skeleton to form porous metals micro structure, referred to as chemical deposition by commercially pure tantalum.Its surperficial tantalum layer thickness of the porous tantalum material that this method obtains is between 40~60 μ m; In whole porous material, tantalum heavily accounts for 99%, and carbon skeleton weight accounts for 1% left and right.Document is further recorded, the comprcssive strength 50~70MPa of this porous material, elastic modelling quantity 2.5~3.5GPa, tensile strength 63MPa, amount of plastic deformation 15%.But the porous tantalum using it as medical embedded material, the mechanical property of its material is obvious weak point as ductility has, and can have influence on the follow-up processing to porous tantalum material itself, such as cutting of profiled member etc.Also all there is such deficiency in the same product obtaining in aforesaid metal powder sintered method.Due to the limitation of its preparation method, the finished product purity of acquisition is inadequate, has carbon skeleton residue again, causes biological safety to reduce.
Summary of the invention
The object of the present invention is to provide the preparation method of a kind of good biocompatibility, medical porous tantalum embedded material that mechanical strength is high.
The object of the invention is to realize by following technological means:
A kind of method of preparing medical porous tantalum embedded material, adopt foam impregnation method sintering to form, its feature is that the solution and the tantalum powder that with organic binder bond and dispersant, are mixed with make tantalum powder slurry, and be cast in Organic Foam Material, dipping is until Organic Foam Material hole is filled with tantalum powder slurry, then be dried and remove the dispersant in the Organic Foam Material that is cast with tantalum powder slurry, under inert gas shielding atmosphere, ungrease treatment is to remove organic binder bond and Organic Foam Material, under vacuum, sintering makes porous sintered body, cooling, under vacuum, annealing and conventional post processing make porous tantalum again, described sintering step is that vacuum is 10
-4pa~10
-3pa, with 10~20 ℃/min, be warming up to 1500~1800 ℃, be incubated 120~240min, with stove, be chilled to 200~300 ℃, with 10~20 ℃/min, be warming up to 1500~1800 ℃, insulation 180~240min again, with 5~10 ℃/min, be warming up to 2000~2200 ℃, insulation 120~360min.
The porous tantalum that adopts preparation method of the present invention to make is specially adapted to the coupling member as load-bearing bone tissue injury or the damaged place of bone.Moreover, described preparation method technique simply, easily control; Whole preparation process is harmless, pollution-free, nonhazardous dust, and human body is had no side effect.And preferentially adopt and can all decompose in sintering process in preparation process, there is no residual binding agent, dispersant, Organic Foam Material etc., will be conducive to guarantee biocompatibility and the biological safety of embedded material.
Described organic binder bond preferably polyethylene alcohol, also can adopt the similar substances such as starch, ethyl cellulose; Described dispersant adopts water, dehydrated alcohol etc., wherein preferred water conventionally.Described Organic Foam Material optimization polyurethane foam can be also the similar substances such as polyether ester foam.
Further feature of the present invention is: adopt its mean diameter to be less than the ta powder that 43 μ m, oxygen content are less than 0.1%, adopting polyvinyl alcohol water solution is that binding agent and water are that dispersant and described tantalum powder are made tantalum powder slurry, Organic Foam Material is polyurethane foam, then vacuum drying is except anhydrating, the porosity of the porous tantalum forming is between 50~70%, pore diameter 150~600 μ m.
Wherein, polyvinyl alcohol is heated to dissolve with distilled water, adopt percentage by weight 2~8% (preferably 4~5%) polyvinyl alcohol water solution and ta powder to make tantalum powder slurry, wherein, it is, in the described polyvinyl alcohol water solution of 1 part, to stir and make starchiness that the ta powder that is 6~9 parts (preferably 7 parts) by weight adds weight; And to be cast in aperture be 0.48~0.89mm, density 0.015g/cm
3~0.035g/cm
3, hardness is greater than 50 °, and (preferably aperture is 0.56~0.72mm, density 0.025g/cm
3, 50 °~80 ° of hardness) polyurethane foam in.
Preferential select mean diameter to be less than 43 μ m, oxygen content to be less than the content that 0.1% ta powder contributes to reduce impurity, to guarantee that material has good mechanical property; Selection aperture is 0.48~0.89mm, density 0.025g/cm
3~0.035g/cm
3, hardness is greater than porosity and the pore diameter that the polyurethane foam of 50 ° contributes to guarantee porous tantalum.Process conditions have been optimized in the such technical finesse of the present invention, will guarantee to implant biocompatibility and the biological safety of porous tantalum material.
The present invention's further feature is on the other hand: dry vacuum keep 10
-2~1Pa vacuum, then, under protective atmosphere, for example vacuum 10
-4~10
-3pa, the ungrease treatment of removing organic binder bond and Organic Foam Material under 400 ℃~800 ℃ conditions of temperature; Sintering processes: vacuum is 10
-4pa~10
-3pa, with 12~15 ℃/min, be warming up to 1600~1800 ℃, be incubated 180~200min, with stove, be chilled to 200~300 ℃, with 16~19 ℃/min, be warming up to 1500~1800 ℃, insulation 220~240min again, with 5~8 ℃/min, be warming up to 2000~2200 ℃, insulation 250~320min, during sintering process insulation, can filling with inert gas protection replace vacuum protection; Finally carry out vacuum annealing processing, wherein vacuum annealing is processed and is referred to that continuation keeps temperature in 1000~1250 ℃ after vacuum-sintering, temperature retention time 1~4 hour, and vacuum is lower than 10
-4~10
-3pa.
Above-mentioned ungrease treatment condition also includes: the speed with 0.5 ℃/min~5 ℃/min is progressively warming up to 400~800 ℃, with argon, passes into and forms protective atmosphere and be incubated 30min~120min;
Vacuum-sintering condition is: vacuum is 10
-4pa~10
-3pa, is warming up to 1800 ℃, is incubated 200min, with stove, is chilled to 200~300 ℃ with 13 ℃/min, then is warming up to 1800 ℃, insulation 230min with 17 ℃/min, with 7 ℃/min, is warming up to 2000~2200 ℃, insulation 300min;
Cooling condition after vacuum-sintering also includes: low vacuum is in 10
-3pa, with not higher than 25 ℃/min, is not less than 10 ℃/min and gradually falls cooldown rate mode, and to sintered porous bodies segmentation cooling down to 800 ℃, each section of temperature retention time 30min~90min, then cools to room temperature with the furnace;
Vacuum annealing condition also includes: low vacuum is in 10
-4pa, rises to 1000~1250 ℃ with the speed higher than 30 ℃/min not, insulation 4h~6h; To be not less than 5 ℃/min but not to be cooled to room temperature higher than the cooldown rate segmentation of 30 ℃/min soon after first slow, the temperature retention time of each section tapers off and is no more than in 1.5h~3h and selects again.
Further feature is on this basis: 60~100 ℃ of described vacuum drying baking temperatures, 4~8 hours drying times; Described ungrease treatment condition also includes: be progressively warming up to 600~800 ℃; with pure argon gas (99.9999%), pass into formation protective atmosphere; speed with 1~5 ℃/min rises to 400 ℃ from room temperature; insulation 30~60min; speed with 0.5~1.5 ℃/min rises to 600~800 ℃ from 400 ℃; insulation 60~120min, described vacuum-sintering condition is: reciprocal of duty cycle is 10
-4pa~10
-3pa, is warming up to 1800 ℃, is incubated 200min, with stove, is chilled to 200~300 ℃ with 13 ℃/min, then is warming up to 1800 ℃, insulation 230min with 17 ℃/min, with 7 ℃/min, is warming up to 2000~2200 ℃, insulation 300min;
Cooling condition after vacuum-sintering also includes: vacuum is 10
-4pa~10
-3pa; Speed with 10~20 ℃/min is cooled to 1500~1600 ℃, insulation 30~60min; Speed with 12~20 ℃/min is cooled to 1200~1250 ℃, insulation 60~90min; Speed with 10~20 ℃/min is cooled to 800 ℃, then furnace cooling; Described vacuum annealing condition also includes: the speed with 15~30 ℃/min rises to 1000~1250 ℃, insulation 240~480min, and vacuum is 10
-4pa~10
-3pa, then be cooled to 1000 ℃ with the speed of 5~10 ℃/min, insulation 90~180min, vacuum is 10
-4pa~10
-3pa; Speed with 10~20 ℃/min is cooled to 800 ℃, insulation 60~120min, and low vacuum is in 10
-4pa; Speed with 20~30 ℃/min is cooled to room temperature, and vacuum is 10
-4pa~10
-3pa.
To vacuum drying, ungrease treatment etc., be wherein the content that contributes to reduce impurity in porous tantalum, improve biocompatibility and biological safety is good and mechanical property; The problem of subsiding that is difficult for to the optimization of Organic Foam Material material with foam framework in solution sintering process; Optimization of process conditions to sintering and annealing steps, the mechanical property that further improves porous tantalum as ductility, reduce the fracture rate of sintering neck.
The porous tantalum material that said method makes, through testing its impurity content lower than 0.5%; This porous tantalum finished product even pore distribution and connection, density 5.00~8.33g/cm
3, porosity 50~70%, pore diameter 150~600 μ m, elastic modelling quantity 2.5~4.0GPa, bending strength 130~150MPa, comprcssive strength 75~88MPa, percentage elongation 9.3%~10.2%.Porous tantalum material of the present invention not only biocompatibility, safety is good, and the special intensity of mechanical property is high, is suitable for very much substituting the osseous tissue at human bearing position.
Accompanying drawing explanation
Fig. 1 is the scanning electron microscope analysis figure (SEM figure) of the porous tantalum structure prepared of preparation method of the present invention;
From accompanying drawing, can be observed: the high hole of porous tantalum of the present invention, even pore distribution is communicated with.From accompanying drawing, can find out that porous tantalum of the present invention interconnected pore is conducive to that osteoblast adheres to, differentiation and growth, promote growing into of bone, can strengthen being connected between implant and bone, be beneficial to and realize biological fixation.
The specific embodiment
Below by embodiment, the present invention is specifically described; be necessary to be pointed out that at this following examples are only used to further illustrate the present invention; can not be interpreted as limiting the scope of the invention, person skilled in art can make some nonessential improvement and adjustment to the present invention according to the invention described above content.
Embodiment 1: weighing polyvinyl alcohol 12.5g, puts into the container that 240ml distilled water is housed; Placing it in heats and stir on electric furnace makes it to become polyvinyl alcohol water solution.With 200g balance, weigh mean diameter and be less than the tantalum powder 60g that 43 microns, oxygen content are less than 0.1%, add the cooling polyvinyl alcohol water solution of 50ml, be uniformly mixed, make it to become tantalum powder slurry.(average pore size is 0.48mm, density 0.025g/cm to select 10 * 10 * 30mm cellular polyurethane foam
3, 50 ° of hardness) and put into wherein cast, until polyurethane foam hole is filled with tantalum powder slurry, the polyurethane foam that goes out to be filled tantalum powder slurry by clip is put into porcelain dish.Dry in vacuum drying oven, 60 ℃ of baking temperatures, 8 hours drying times, vacuum keep 1Pa.Ungrease treatment: low vacuum is in 10
-4pa, 600 ℃ of temperature, temperature retention time 120 minutes.Vacuum-sintering: described sintering step is that vacuum is 10
-4pa~10
-3pa, is warming up to 1800 ℃, is incubated 200min, with stove, is chilled to 200~300 ℃ with 13 ℃/min, then is warming up to 1800 ℃, insulation 230min with 17 ℃/min, with 7 ℃/min, is warming up to 2000~2200 ℃, insulation 300min; The protection of sintering process applying argon gas, removes surface dirt and dirt after taking-up product, and the sample making carries out conventional post processing again and obtains porous tantalum finished product.
Inventor detects the porous material density of above-mentioned porous tantalum finished product, porosity, aperture and various mechanical property by standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: its impurity content is lower than 0.5% finished product, its even pore distribution and connection, density 6.7g/cm
3, porosity 56%, hole average diameter 300 μ m, elastic modelling quantity 3.0GPa, bending strength 150MPa, comprcssive strength 82MPa, percentage elongation 9.8%.
Embodiment 2: weighing polyvinyl alcohol 10g, puts into the container that 200ml distilled water is housed; Placing it in heats and stir on electric furnace makes it to become polyvinyl alcohol water solution.With 200g balance, weigh mean diameter and be less than the tantalum powder 40g that 43 microns, oxygen content are less than 0.1%, add 32ml polyvinyl alcohol water solution, be uniformly mixed, make it to become tantalum powder slurry.(average pore size is 0.56mm, density 0.030g/cm to select 10 * 10 * 25mm cellular polyurethane foam
3, 60 ° of hardness) and put into wherein cast, until polyurethane foam hole is filled with tantalum powder slurry, the polyurethane foam that goes out to be filled tantalum powder slurry by clip is put into porcelain dish.Dry in vacuum drying oven, 100 ℃ of baking temperatures, 4 hours drying times, vacuum keep 10
-2pa.Ungrease treatment: vacuum 10
-4pa, 800 ℃ of temperature, temperature retention time 120 minutes.Vacuum-sintering: described sintering step is that vacuum is 10
-4pa~10
-3pa; with 10 ℃/min, be warming up to 1600 ℃, be incubated 240min, with stove, be chilled to 200~300 ℃; with 20 ℃/min, be warming up to 1500 ℃, insulation 180min again; with 5 ℃/min, be warming up to 2000~2200 ℃, insulation 360min; the protection of sintering process applying argon gas; after taking out product, remove surface dirt and dirt, the sample making carries out conventional post processing again and obtains porous tantalum finished product.
Inventor detects the porous material density of above-mentioned porous tantalum finished product, porosity, aperture and various mechanical property by standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: its impurity content is lower than 0.5% finished product, its even pore distribution and connection, density 8.0g/cm
3, porosity 66%, hole average diameter 400 μ m, elastic modelling quantity 3.5GPa, bending strength 140MPa, comprcssive strength 75MPa, percentage elongation 10.1%.
Embodiment 3: weighing polyvinyl alcohol 11g, puts into the container that 220ml distilled water is housed; Placing it in heats and stir on electric furnace makes it to become polyvinyl alcohol water solution.With 200g balance, weigh mean diameter and be less than the tantalum powder 45g that 43 microns, oxygen content are less than 0.1%, add 36ml polyvinyl alcohol water solution, be uniformly mixed, make it to become tantalum powder slurry.(average pore size is 0.70mm, density 0.035g/cm to select 8 * 8 * 25mm cellular polyurethane foam
3, 70 ° of hardness) and put into wherein cast, until polyurethane foam hole is filled with tantalum powder slurry, the polyurethane foam that goes out to be filled tantalum powder slurry by clip is put into porcelain dish.Dry in vacuum drying oven, 80 ℃ of baking temperatures, 6 hours drying times, vacuum keep 10
-1pa.Ungrease treatment: vacuum 10
-3pa, 700 ℃ of temperature, temperature retention time 90 minutes.Vacuum-sintering: described sintering step is that vacuum is 10
-4pa~10
-3pa; with 20 ℃/min, be warming up to 1800 ℃, be incubated 120min, with stove, be chilled to 200~300 ℃; with 10 ℃/min, be warming up to 1800 ℃, insulation 240min again; with 10 ℃/min, be warming up to 2000~2200 ℃, insulation 120min; the protection of sintering process applying argon gas; after taking out product, remove surface dirt and dirt, the sample making carries out conventional post processing again and obtains porous tantalum finished product.
Inventor detects the porous material density of above-mentioned porous tantalum finished product, porosity, aperture and various mechanical property by standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: its impurity content is lower than 0.5% finished product, its even pore distribution and connection, density 5.0g/cm
3, porosity 70%, hole average diameter 450 μ m, elastic modelling quantity 5.5GPa, bending strength 130MPa, comprcssive strength 86MPa, percentage elongation 9.5%.
Embodiment 4: weighing polyvinyl alcohol 12g, puts into the container that 230ml distilled water is housed; Placing it in heats and stir on electric furnace makes it to become polyvinyl alcohol water solution.With 200g balance, weigh mean diameter and be less than the tantalum powder 50g that 43 microns, oxygen content are less than 0.1%, add 40ml polyvinyl alcohol water solution, be uniformly mixed, make it to become tantalum powder slurry.(aperture is 0.60mm, density 0.027g/cm to select 12 * 12 * 30mm cellular polyurethane foam
3, 80 ° of hardness) and put into wherein cast, until polyurethane foam hole is filled with tantalum powder slurry, the polyurethane foam that goes out to be filled tantalum powder slurry by clip is put into porcelain dish.Dry in vacuum drying oven, 90 ℃ of baking temperatures, 5 hours drying times, vacuum keep 1Pa.Ungrease treatment: vacuum 10
-4~10
-3pa, 500 ℃ of temperature, temperature retention time 120 minutes.Vacuum-sintering: described sintering step is that vacuum is 10
-4pa~10
-3pa; with 13 ℃/min, be warming up to 1700 ℃, be incubated 210min, with stove, be chilled to 200~300 ℃; with 15 ℃/min, be warming up to 1600 ℃, insulation 210min again; with 8 ℃/min, be warming up to 2000~2200 ℃, insulation 260min; the protection of sintering process applying argon gas; after taking out product, remove surface dirt and dirt, the sample making carries out conventional post processing again and obtains porous tantalum finished product.
Inventor detects the porous material density of above-mentioned porous tantalum finished product, porosity, aperture and various mechanical property by standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: its impurity content is lower than 0.5% finished product, its even pore distribution and connection, density 8.33g/cm
3, porosity 50%, hole average diameter 350 μ m, elastic modelling quantity 2.7GPa, bending strength 142MPa, comprcssive strength 81MPa, percentage elongation 9.8%.
Embodiment 5: a kind of porous tantalum, and it be take particle diameter and is less than 43 μ m, oxygen content to be less than 0.1% ta powder be raw material, and the polyvinyl alcohol water solution of take is made tantalum powder slurry as binder solution, and is cast in polyurethane foam carrier; Then vacuum drying, ungrease treatment, vacuum-sintering, vacuum annealing and conventional post processing make.
Wherein, the polyurethane foam of selecting, its aperture is 0.72~0.56mm, density 0.025g/cm
3, 50 °~80 ° of hardness;
Vacuum drying: vacuum keep 10
-2~1Pa, to remove the moisture in the polyurethane foam of filling with tantalum powder slurry;
Ungrease treatment: under inert gas shielding atmosphere or vacuum 10
-4~10
-3pa, 400 ℃~800 ℃ of temperature, and temperature retention time 30~120 minutes is to remove polyvinyl alcohol and polyurethane foam wherein;
Vacuum-sintering: described sintering step is that vacuum is 10
-4pa~10
-3pa, is warming up to 1650 ℃, is incubated 190min, with stove, is chilled to 200~300 ℃ with 16 ℃/min, then is warming up to 1800 ℃, insulation 200min with 18 ℃/min, with 6 ℃/min, is warming up to 2000~2200 ℃, insulation 270min;
Vacuum annealing: after vacuum-sintering, continue to keep temperature in 1000~1250 ℃, temperature retention time 1~4 hour, vacuum is 10
-4~10
-3pa, to carry out stress relief annealing processing; The sample making carries out conventional post processing again and obtains porous tantalum finished product.
Inventor detects the porous material density of above-mentioned porous tantalum finished product, porosity, aperture and various mechanical property by standards such as GB/T5163-2006, GB/T5249-1985, GB/T6886-2001: its impurity content is lower than 0.5% finished product, its even pore distribution and connection, density 6.3g/cm
3, porosity 62%, hole average diameter 220 μ m, elastic modelling quantity 3.3GPa, bending strength 136MPa, comprcssive strength 84MPa, percentage elongation 10.2%.
In the method providing at above-described embodiment 5, we can also do other selections to wherein each kind of condition can obtain porous tantalum of the present invention equally.
Gained porous tantalum finished product is pressed preceding method and is detected:
Embodiment |
6 |
7 |
8 |
Density (g/cm
3)
|
6.9 |
7.5 |
7.8 |
Porosity (%) |
50 |
64 |
70 |
Aperture (μ m) |
170 |
410 |
280 |
Elastic modelling quantity (GPa) |
2.6 |
3.5 |
4.0 |
Bending strength (MPa) |
140 |
130 |
150 |
Comprcssive strength (MPa) |
80 |
88 |
76 |
Percentage elongation (%) |
9.5 |
9.8 |
10.0 |