CN108395237B

CN108395237B - High-strength calcium silicophosphate biological ceramic material and preparation method thereof

Info

Publication number: CN108395237B
Application number: CN201810175886.1A
Authority: CN
Inventors: 邓繁艳; 宁聪琴
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Jiliwei Biotechnology Partnership (L.P.)
Priority date: 2018-03-02
Filing date: 2018-03-02
Publication date: 2020-07-03
Anticipated expiration: 2038-03-02
Also published as: CN108395237A

Abstract

The invention relates to a high-strength calcium silicophosphate biological ceramic material and a preparation method thereof. The method comprises the following steps: (1) uniformly mixing zinc oxide powder, calcium silicophosphate powder and a binder to obtain a mixture, and then forming the mixture to obtain a ceramic blank; and (2) sintering the ceramic blank obtained in the step (1) to obtain the high-strength calcium silicophosphate biological ceramic material. The method has the advantages of simple process, controllable process, easy operation, low sintering temperature and the like; the high-strength calcium silicophosphate biological ceramic material prepared by the invention has the advantages of low porosity (the porosity can be reduced to about 1%), high bending strength (the bending strength can be improved to 65-90 MPa), good cell compatibility and the like, is particularly suitable for being used as a hard tissue repair material, is a biological and medical material with great potential, and can be used as a bone tissue repair, filling and dental repair material.

Description

High-strength calcium silicophosphate biological ceramic material and preparation method thereof

Technical Field

The invention belongs to the field of preparation of biological ceramics, and particularly relates to a high-strength calcium silicophosphate biological ceramic material and a preparation method thereof.

Background

With the increase in human life, the incidence of fractures due to trauma, old bone fragility or disease is expected to rise to 400% by 2050, with the consequent enormous medical consumption, with an estimated increase in annual morbidity/mortality costs worldwide of about $ 80 billion and an increase in handling costs of about $ 80 ten thousand, showing the enormous market potential of bone repair materials worldwide. From the domestic situation, China is a large country with 13 hundred million population and more than 8000 ten thousand disabled people, and according to the report of the civil administration, as of 2005, the number of patients with limb disabilities in China is more than 1500 ten thousand, wherein about 800 ten thousand disabled people have millions of patients with Kaschin-Beck disease caused by rheumatoid disease; and the data of the sixth national census show that China is stepping into the elderly society, and the elderly over 60 years old reach 1.78 hundred million, accounting for about 13.26% of the national population. Therefore, the research on bone tissue repair materials has great social significance and economic benefit.

With the development of material science, artificial bone repair and substitute materials have become hot spots for research and development of various countries in recent decades, and are one of important contents for biomedical material research. At present, inorganic materials are still the first choice for bone repair and replacement materials, and the research is also the most extensive. The calcium phosphate bioceramic which is widely applied clinically at present is similar to inorganic components of a human body, and has no toxicity, harm and carcinogenic effect on the human body due to good biocompatibility, but lacks bioactivity and has unsatisfactory degradability.

Professor Hench in the united states discovered that silicon has an osteogenesis-inducing effect in the early 70 s of the last century, and thus bioactive materials containing silicon were extensively studied. Our earlier studies found calcium silicophosphate (Ca)₅(PO₄)₂SiO₄CPS) material has a crystal structure similar to hydroxyapatite, wherein the silicon component induces the formation of osteoid apatite to promote the formation of new bone; simultaneous calciumAnd degradation of the phosphorus component can provide calcium and phosphorus for new bone growth, thereby accelerating the bone regeneration process.

Calcium silicophosphate as a newly developed biological material is internationally focused on the research and study of the preparation method and the biological performance thereof, and the previous research work shows that the material system with excellent mechanical property and biological activity is difficult to obtain by the current preparation method. Therefore, how to optimize the sintering performance of the calcium silicophosphate ceramic and realize the perfect combination of high mechanical property and good biological property is a key problem that the calcium silicophosphate needs to be solved in the clinical field.

Disclosure of Invention

In order to solve one or more technical problems, the invention aims to provide a high-strength calcium silicophosphate bioceramic material and a preparation method thereof. The method has the advantages of simple process, controllable process, easy operation, low sintering temperature and the like, and the high-strength calcium silicophosphate biological ceramic material prepared by the method has the advantages of low porosity, high bending strength, good cell compatibility and the like.

The invention provides a preparation method of a high-strength calcium silicophosphate biological ceramic material in a first aspect, which comprises the following steps:

(1) uniformly mixing zinc oxide powder, calcium silicophosphate powder and a binder to obtain a mixture, and then forming the mixture to obtain a ceramic blank; and

(2) sintering the ceramic blank obtained in the step (1) to obtain the high-strength calcium silicophosphate biological ceramic material.

Preferably, the mass ratio of the zinc oxide powder to the calcium silicophosphate powder is (0.1-5): (95-99.9), preferably (0.5-5): (95-99.5).

Preferably, the sintering comprises a first temperature stage sintering and a second temperature stage sintering; the sintering temperature of the first temperature stage is 500-700 ℃, and the sintering time of the first temperature stage is 30-120 min; the sintering temperature of the second temperature stage is 800-1400 ℃, preferably 1100-1400 ℃, more preferably 1250-1350 ℃, and the sintering time of the second temperature stage is 30-360 min, preferably 60-240 min.

Preferably, the temperature is raised to the sintering temperature in the step (2) by adopting a heating rate of 1-10 ℃/min.

Preferably, the amount of the binder is 0.1-5 wt%, preferably 0.1-2 wt% of the sum of the amounts of the zinc oxide powder and the calcium silicophosphate powder.

Preferably, the binder is a water-based binder.

Preferably, in the step (1), water is used as a ball milling medium, and the mixture is uniformly mixed by ball milling.

Preferably, in the step (1), the mixture is subjected to dry press forming and cold isostatic press forming in sequence.

Particularly, the pressure of the dry pressing is 5-100 MPa, preferably 10-50 MPa, and the pressure maintaining time of the dry pressing is 1-10 min, preferably 2-8 min; and/or the pressure of the cold isostatic pressing is 50-400 MPa, preferably 100-300 MPa, and the pressure maintaining time of the cold isostatic pressing is 1-10 min, preferably 2-8 min.

The invention provides in a second aspect the high-strength calcium silicophosphate bioceramic material prepared by the preparation method of the first aspect of the invention; preferably, the flexural strength of the high-strength calcium silicophosphate biological ceramic material is not less than 65MPa, and the porosity is less than 5%.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the invention takes calcium silicophosphate powder as the main component, and adds a small amount of zinc oxide as a sintering aid to prepare the zinc-containing high-strength calcium silicophosphate biological ceramic material which takes calcium silicophosphate as the main phase and can also have zinc oxide and a third phase of akermanite; compared with pure calcium silicophosphate bioceramic material, the high-strength calcium silicophosphate bioceramic material prepared by the method has a compact microstructure, the sintering property and the mechanical property of the calcium silicophosphate bioceramic material are obviously improved, in addition, the high-strength calcium silicophosphate bioceramic material has more excellent biological property, has better osteogenic activity due to the existence of zinc, has a certain inhibition effect on osteoclasts, and is beneficial to improving the biological activity and the degradation property of the calcium silicophosphate bioceramic material.

(2) Compared with the prior art, the method has the advantages that zinc oxide is used as a sintering aid, the sintering temperature is reduced (the sintering temperature is reduced to 1300 ℃ or even lower) through liquid phase sintering, and the prepared high-strength calcium silicophosphate biological ceramic material is low in sintering temperature, low in porosity (porosity), good in mechanical property and good in biological property; on the basis of overcoming the defects of the traditional normal pressure sintering process, the method solves the problems of difficult sintering and poor mechanical property of the calcium silicophosphate biological ceramic, and is suitable for preparing the calcium silicophosphate biological ceramic material with high mechanical property on a large scale.

(3) The method has the advantages of simple process, controllable process, easy operation, low sintering temperature and the like; the high-strength calcium silicophosphate biological ceramic material prepared by the method has the advantages of low porosity (the porosity can be reduced to about 1%), high bending strength (the bending strength can be improved to 65-90 MPa), good cell compatibility and the like, is particularly suitable for being used as a hard tissue repair material, is a biological and medical material with great potential, and can be used for repairing and filling bone tissues, dental repair materials and the like.

Drawings

FIG. 1 is a cross-sectional profile of the high strength calcium silicophosphate bioceramic material prepared in example 1.

FIG. 2 is a cross-sectional profile of the high-strength calcium silicophosphate bioceramic material prepared in example 2.

FIG. 3 is a cross-sectional profile of the high strength calcium silicophosphate bioceramic material prepared in example 3.

FIG. 4 is a cross-sectional profile of the high strength calcium silicophosphate bioceramic material prepared in example 4.

FIG. 5 is a cross-sectional profile of the high strength calcium silicophosphate bioceramic material prepared in example 5.

FIG. 6 is a cross-sectional profile of the high strength calcium silicophosphate bioceramic material prepared in example 6.

FIG. 7 is a cross-sectional profile of the calcium silicophosphate bioceramic material prepared in comparative example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

(2) and (2) sintering the ceramic blank obtained in the step (1) (normal pressure sintering) to obtain the high-strength calcium silicophosphate biological ceramic material.

In the invention, a normal pressure sintering process is adopted, the process is simple and controllable, biologically safe and nontoxic zinc oxide is adopted as a sintering aid, calcium silicophosphate is adopted as a main phase, a binder is added, and the high-strength calcium silicophosphate biological ceramic material is prepared by uniformly mixing, molding and then performing normal pressure sintering; according to the invention, zinc oxide is used as a sintering aid, the sintering temperature is reduced through low-temperature co-melting, a liquid phase (liquid phase sintering) is formed among ceramic particles in a sintering temperature range, the densification of the ceramic particles is promoted, and in addition, the zinc oxide can also obviously improve the mechanical property of the calcium silicophosphate biological ceramic material, so that the high-strength calcium silicophosphate biological ceramic material with low porosity (porosity), excellent mechanical property and further improved biological property is prepared. The high-strength calcium silicophosphate biological ceramic material prepared by the invention takes calcium silicophosphate as a main phase and can also contain zinc oxide and a third phase of akermanite.

In the present invention, the zinc oxide powder is selected from the group consisting of hexagonal zinc oxide powder, cubic zinc oxide powder and octahedral zinc oxide powder, and hexagonal zinc oxide powder is preferred because hexagonal zinc oxide has the highest stability and is most easily available, thus being cheap and reducing the cost of raw materials.

In the present invention, the calcium silicophosphate powder can be prepared, for example, by a sol-gel method, a solid-phase reaction method, a hydrothermal method, or other methods; preferably, the calcium silicophosphate powder is prepared by a sol-gel method. The calcium silicophosphate powder can be prepared by itself, and the preparation method can be, for example:

(a) mixing 22.4 ml of ethyl orthosilicate with 4 ml of nitric acid with the concentration of 2 mol/L, adding 9.6 ml of deionized water and 5.8 ml of anhydrous ethanol, stirring at room temperature for 2 hours, then adding 34.2 ml of triethyl phosphate, continuing stirring for 2 hours, then adding 118.1 g of calcium nitrate tetrahydrate, and stirring for 4 hours to obtain calcium silicophosphate sol; aging the sol at 60 ℃ for 48 hours to obtain gel; the gel was dried at 120 ℃ for 120 hours to give a xerogel.

(b) Grinding the xerogel into powder, calcining for 1-10 hours, preferably 2-6 hours at 1000-1600 ℃, preferably 1100-1400 ℃, for example, at 1400 ℃ (heating rate 2 ℃/min), and obtaining calcium silicophosphate (Ca)₅(PO₄)₂SiO₄CPS) powder.

According to some preferred embodiments, the mass ratio of the zinc oxide powder to the calcium silicophosphate powder is (0.1-5): (95-99.9), preferably (0.5-5): (95-99.5). In the present invention, the sum of the mass of the zinc oxide powder and the calcium silicophosphate powder is defined as the total mass of the powder, that is, the zinc oxide powder accounts for 0.1 to 5 wt%, preferably 0.5 to 5 wt% (e.g., 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, or 5.0 wt%) of the total mass of the powder, and the calcium silicophosphate powder accounts for 95 to 99.9 wt%, preferably 95 to 99.5 wt% of the total mass of the powder. In the present invention, the mass percentage of the zinc oxide powder to the total mass of the powder is referred to as the added amount of zinc oxide.

In the invention, preferably, the zinc oxide powder accounts for 0.5-5 wt% of the total mass of the powder, and within the range of 0.5-5 wt%, the mass percentage of the zinc oxide powder is moderate and best, as the addition amount of the zinc oxide powder is continuously increased, the liquid phase amount of the zinc oxide powder generated in the sintering process is reduced, the porosity of the prepared high-strength calcium silicophosphate biological ceramic material is not reduced and increased, and the bending strength is also reduced. Therefore, the moderate zinc oxide content is beneficial to forming enough liquid phase and promoting the growth of crystal grains so as to discharge air holes.

According to some preferred embodiments, the sintering may be performed directly at a sintering temperature, which is in the range of 500 ℃ to 1400 ℃ (e.g., 500 ℃, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, or 1400 ℃), preferably 1100 ℃ to 1400 ℃ (e.g., 1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃, 1300 ℃, 1350 ℃, or 1400 ℃), more preferably 1250 ℃ to 1350 ℃ (e.g., 1250 ℃, 1300 ℃, or 1350 ℃); the sintering time is 30-360 min (such as 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 or 360min), preferably 60-240 min (such as 60, 90, 120, 150, 180, 210 or 240 min). In the temperature range of 1100-1400 ℃, the zinc oxide can fully play a role as a sintering aid, ceramic particles can be fully sintered, the size of crystal grains is not too large due to overhigh temperature, and the crystal grains are not melted due to overhigh liquid phase content; in addition, different sintering temperatures in the present invention also have an effect on the flexural strength and open porosity of the high strength calcium silicophosphate bioceramic material.

According to some preferred embodiments, the sintering comprises a first temperature stage sintering and a second temperature stage sintering; the sintering temperature of the first temperature stage is 500-700 ℃ (such as 500 ℃, 550 ℃, 600 ℃, 650 ℃ or 700 ℃), and the sintering time of the first temperature stage is 30-120 min (such as 30, 60, 90 or 120 min); the temperature of the second temperature stage sintering is 800 ℃ to 1400 ℃ (e.g., 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃ or 1400 ℃), preferably 1100 ℃ to 1400 ℃ (e.g., 1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃, 1300 ℃, 1350 ℃ or 1400 ℃), more preferably 1250 ℃ to 1350 ℃ (e.g., 1250 ℃, 1300 ℃ or 1350 ℃), and the time of the second temperature stage sintering is 30 min to 360min (e.g., 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 or 360min), preferably 60min to 240min (e.g., 60, 90, 120, 150, 180, 210 or 240 min). In the present invention, it is preferable to perform a relatively low-temperature sintering (first temperature stage sintering) on the ceramic green body and then perform a relatively high-temperature sintering (second temperature stage sintering), and it has been unexpectedly found that the porosity of the high-strength calcium silicophosphate bioceramic material obtained can be effectively reduced and the bending strength thereof can be improved, possibly because the organic substance (binder) can be effectively removed during the first temperature stage sintering, and the influence of the organic substance on the sintering performance and mechanical properties of the high-strength calcium silicophosphate bioceramic material during the relatively high-temperature sintering can be avoided.

According to some preferred embodiments, the temperature is raised to the sintering temperature in step (2) using a ramp rate of 1 ℃/min to 10 ℃/min (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 ℃/min). In the invention, the required sintering temperature is increased by adopting a relatively slow temperature rise rate (1-10 ℃/min), which is beneficial to forming the high-strength calcium silicophosphate biological ceramic material with uniform tissue structure and high compactness.

According to some preferred embodiments, the binder is used in an amount of 0.1 to 5 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, or 5.0 wt%), preferably 0.1 to 2 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, or 2.0 wt%) of the sum of the amounts of the zinc oxide powder and the calcium silicophosphate powder.

In the present invention, the binder is, for example, an organic binder, and the binder is preferably a water-based binder. In the present invention, the binder may be added in the form of a solution, for example, when the water-based binder is polyvinyl alcohol, it may be added in a form of a polyvinyl alcohol aqueous solution, and the concentration of the polyvinyl alcohol aqueous solution is preferably 1 to 10 wt% (e.g., 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%). In particular, in the present invention, in addition to polyvinyl alcohol, a water-based binder such as polyethylene glycol or starch may be used.

According to some preferred embodiments, in step (1), water is used as a milling medium, and the mixture is mixed uniformly by ball milling (for example, using a planetary ball mill). In the present invention, the ball milling by the planetary ball mill is referred to as planetary ball milling.

According to some preferred embodiments, in the step (1), the mixture is subjected to dry-pressing and cold isostatic pressing in sequence; the pressure of the dry pressing is 5-100 MPa, preferably 10-50 MPa (such as 10, 20, 30, 40 or 50MPa), and the dwell time of the dry pressing is 1-10 min, preferably 2-8 min (such as 2, 3, 4, 5, 6, 7 or 8 min); and/or the pressure of the cold isostatic pressing is 50-400 MPa, preferably 100-300 MPa (such as 100, 150, 200, 250 or 300MPa), and the dwell time of the cold isostatic pressing is 1-10 min, preferably 2-8 min (such as 2, 3, 4, 5, 6, 7 or 8 min). In the invention, the mixture is sequentially subjected to dry pressing and cold isostatic pressing, which is favorable for obtaining a ceramic blank with certain strength, thereby being favorable for obtaining the high-strength calcium silicophosphate biological ceramic material with uniform tissue structure, high densification degree and high bending strength. In particular, the molding may be performed by another molding method in the present invention.

According to some more specific embodiments, step (1) is: weighing hexagonal zinc oxide powder and calcium silicophosphate powder according to a ratio, taking water as a ball milling medium, adding an organic binder (polyvinyl alcohol aqueous solution), carrying out ball milling by adopting a planetary ball mill to uniformly mix the raw materials to obtain a uniformly dispersed mixture of the hexagonal zinc oxide and the calcium silicophosphate powder, then carrying out drying treatment on the mixture (drying temperature is 50-80 ℃), and after carrying out drying treatment, sieving the mixture to obtain a mixture with uniform particle size, wherein the mass ratio of the total mass of the hexagonal zinc oxide powder and the calcium silicophosphate powder to the using amount of the ball milling medium is (1-3): (2-6), wherein the ball milling time can be 2-12 hours; and then sequentially carrying out dry pressing forming and cold isostatic pressing forming on the mixture to obtain a ceramic blank.

According to some more specific embodiments, step (2) is: and sintering the formed ceramic blank at normal pressure, namely heating to 500 ℃ at the heating rate of 1-10 ℃/min, preserving heat for 0.5-2 h to remove organic matters, then heating to the final sintering temperature of 800-1400 ℃ at the heating rate of 1-10 ℃/min, preserving heat for 30 minutes-6 hours, and cooling along with the furnace.

The invention provides in a second aspect the high-strength calcium silicophosphate bioceramic material prepared by the preparation method of the first aspect of the invention; preferably, the flexural strength of the high-strength calcium silicophosphate biological ceramic material is not less than 65MPa, and the porosity is less than 5%. In the present invention, the porosity is also referred to as open porosity or porosity.

Example 1

Firstly weighing 0.5g of hexagonal zinc oxide powder and 49.5g of calcium silicophosphate powder, adding 50g of deionized water, adding 5.0g of a polyvinyl alcohol aqueous solution with the solution concentration of 10 wt%, carrying out planetary ball milling for 3h to prepare a uniformly dispersed mixture, then drying for 12 h at 60 ℃, sieving to obtain a mixture with uniform particle size, sequentially carrying out dry pressing (dry pressing forming pressure of 50MPa, pressure holding time of 5min) and cold isostatic pressing (cold isostatic pressing forming pressure of 200MPa, pressure holding time of 5min) on the obtained mixture to obtain a test strip with the length, width and height of 3 × 4 × 40mm, finally placing the test strip on an alumina crucible cover for normal pressure sintering, heating to 500 ℃ at the heating rate of 2 ℃/min to remove a binder, heating to 1300 ℃ (final sintering temperature of 2 ℃/min) to carry out heat preservation for 2h, and finally preparing the high-strength calcium silicophosphate biological ceramic material with the zinc oxide addition of 1 wt%.

The cross-sectional morphology of the high-strength calcium silicophosphate biological ceramic material prepared in the embodiment, which is observed by a scanning electron microscope (SEM, S-3400N type I, HITACHI, Japan), is shown in FIG. 1; the physical properties and mechanical properties of the high-strength calcium silicophosphate bioceramic material prepared in this example are shown in table 1, wherein the bending strength is measured by a three-point bending method (Instron-5566, Instron co.ltd., USA); the sintering shrinkage is calculated by measuring the size change of the ceramic sample before and after sintering; the open porosity is tested by the Archimedes drainage method (national standard GB-T1966-1996).

It can be seen from the combination of fig. 1 and table 1 that, in comparison with the method without adding hexagonal zinc oxide (comparative example 1), the high-strength calcium silicophosphate bioceramic material prepared in this example has the presence of akermanite, and therefore has significantly improved bending strength and significantly reduced open porosity.

Example 2

Example 2 is essentially the same as example 1, except that:

the dosage of the hexagonal zinc oxide powder is 1.5g, and the dosage of the calcium silicophosphate powder is 48.5g, so as to prepare the high-strength calcium silicophosphate biological ceramic material with 3 wt% of zinc oxide; the other differences are shown in table 1.

The cross-sectional morphology of the high-strength calcium silicophosphate bioceramic material prepared in this example is shown in fig. 2. It can be seen from the combination of fig. 2 and table 1 that the densification degree of the high-strength calcium silicophosphate bioceramic material is improved with the increase of the addition amount of zinc oxide, and the content of akermanite and the content of residual zinc oxide are increased.

Example 3

Example 3 is essentially the same as example 1, except that:

the dosage of the hexagonal zinc oxide powder is 2.5g, and the dosage of the calcium silicophosphate powder is 47.5g, so as to prepare the high-strength calcium silicophosphate biological ceramic material with 5 wt% of zinc oxide; the other differences are shown in table 1.

The cross-sectional morphology of the high-strength calcium silicophosphate bioceramic material prepared in this example is shown in fig. 3. From the combination of FIG. 3 and Table 1, it can be seen that as the amount of zinc oxide added is further increased, the reduction of the open porosity of the high-strength calcium silicophosphate bioceramic material is reduced, and the content of residual zinc oxide is increased.

Example 4

Example 4 is essentially the same as example 1, except that:

the final sintering temperature is 1340 ℃; the other differences are shown in table 1.

The cross-sectional morphology of the high-strength calcium silicophosphate bioceramic material prepared in this example is shown in fig. 4. It can be seen from fig. 4 and table 1 that the densification degree of the high-strength calcium silicophosphate bioceramic material is further improved with the increase of the final sintering temperature and the addition of zinc oxide.

Example 5

Example 5 is essentially the same as example 2, except that: the final sintering temperature is 1340 ℃; the other differences are shown in table 1.

The cross-sectional morphology of the high-strength calcium silicophosphate bioceramic material prepared in this example is shown in fig. 5. It can be seen from the combination of fig. 5 and table 1 that the densification degree of the high-strength calcium silicophosphate bioceramic material is further improved and the content of the akermanite is increased with the increase of the final sintering temperature and the increase of the addition amount of the zinc oxide.

Example 6

Example 6 is essentially the same as example 3, except that: the final sintering temperature is 1340 ℃; the other differences are shown in table 1.

The cross-sectional morphology of the high-strength calcium silicophosphate bioceramic material prepared in this example is shown in fig. 6. It can be seen from the combination of fig. 6 and table 1 that the densification degree of the high-strength calcium silicophosphate bioceramic material is further improved and the content of the akermanite is increased with the increase of the final sintering temperature and the further increase of the addition amount of the zinc oxide.

Example 7

Example 7 is essentially the same as example 1, except that:

placing the test strip on an alumina crucible cover for normal pressure sintering, directly heating to 1300 ℃ (the final sintering temperature) at the heating rate of 2 ℃/min, and preserving the temperature for 4 hours to obtain the high-strength calcium silicophosphate bioceramic material with 1 wt% of zinc oxide; the other differences are shown in table 1.

Comparative example 1

Comparative example 1 is substantially the same as example 1 except that:

the hexagonal zinc oxide powder was not mixed in the mixture, i.e., the amount of zinc oxide added was 0 wt%.

The bending strength of the calcium silicophosphate biological ceramic material prepared by the comparative example is 40.9MPa, the open porosity is 22.6 percent, and the cross-sectional topography is shown in FIG. 7.

Comparative example 2

Comparative example 2 is substantially the same as example 1 except that:

replacing hexagonal zinc oxide powder with hexagonal boron nitride powder; the other differences are shown in table 1.

Table 1: physical and mechanical properties of examples 1 to 7 and comparative examples 1 to 2.

The experimental results show that: the high-strength calcium silicophosphate biological ceramic material prepared by the invention has the three-point bending strength not lower than 65MPa and the open porosity lower than 5%. Compared with the calcium silicophosphate biological ceramic material which is prepared under the same conditions and does not add zinc oxide as a sintering aid, the porosity is obviously reduced, and the bending strength is obviously improved. The invention solves the problems of difficult sintering and poor mechanical property of the calcium silicophosphate biological ceramic material under normal pressure by adding zinc oxide (preferably hexagonal zinc oxide) as a sintering aid. The preparation method has the characteristics of simple preparation process, controllable process, low cost and the like, and can remarkably expand the application of the calcium silicophosphate biological ceramic material in the aspect of bone replacement biological ceramic. Therefore, the high-strength calcium silicophosphate biological ceramic material prepared by the invention can be applied to the field of biological materials.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The preparation method of the high-strength calcium silicophosphate biological ceramic material is characterized by comprising the following steps of:

(1) uniformly mixing zinc oxide powder, calcium silicophosphate powder and a binder to obtain a mixture, and then forming the mixture to obtain a ceramic blank; the zinc oxide powder is hexagonal zinc oxide powder; the mass ratio of the zinc oxide powder to the calcium silicophosphate powder is (0.1-5): (95-99.9); the amount of the binder accounts for 0.1-5 wt% of the sum of the amounts of the zinc oxide powder and the calcium silicophosphate powder; and

(2) sintering the ceramic blank obtained in the step (1) to obtain a high-strength calcium silicophosphate biological ceramic material, wherein the high-strength calcium silicophosphate biological ceramic material takes calcium silicophosphate as a main phase, and also contains zinc oxide and a third phase of akermanite, the bending strength is not lower than 65MPa, and the porosity is lower than 5%;

in the step (2), the sintering comprises first temperature stage sintering and second temperature stage sintering; the sintering temperature of the first temperature stage is 500-700 ℃, and the sintering time of the first temperature stage is 30-120 min; the sintering temperature of the second temperature stage is 1250-1350 ℃, and the sintering time of the second temperature stage is 30-360 min.

2. The method of claim 1, wherein:

the mass ratio of the zinc oxide powder to the calcium silicophosphate powder is (0.5-5): (95-99.5).

3. The method of claim 1, wherein:

and the sintering time of the second temperature stage is 60-240 min.

4. The method of claim 1, wherein:

in the step (2), the temperature is increased to the sintering temperature by adopting the heating rate of 1-10 ℃/min.

5. The method of claim 1, wherein:

the amount of the binder accounts for 0.1-2 wt% of the sum of the amounts of the zinc oxide powder and the calcium silicophosphate powder.

6. The method of claim 1, wherein:

the binder is a water-based binder.

7. The method of claim 1, wherein:

in the step (1), water is used as a ball milling medium, and the water is uniformly mixed by ball milling.

8. The method of claim 1, wherein:

in the step (1), the mixture is subjected to dry pressing and cold isostatic pressing in sequence.

9. The method of claim 8, wherein:

the pressure of the dry pressing is 5-100 MPa, and the pressure maintaining time of the dry pressing is 1-10 min; and/or

The pressure of the cold isostatic pressing is 50-400 MPa, and the pressure maintaining time of the cold isostatic pressing is 1-10 min.

10. The method of claim 9, wherein:

the pressure of the dry pressing is 10-50 MPa, and the pressure maintaining time of the dry pressing is 2-8 min; and/or

The pressure of the cold isostatic pressing is 100-300 MPa, and the pressure maintaining time of the cold isostatic pressing is 2-8 min.

11. The high-strength calcium silicophosphate bioceramic material prepared by the method according to any one of claims 1 to 10.