AU2018414989B2

AU2018414989B2 - Calcium polyphosphate/wollastonite bio-composite ceramic material and preparation method therefor

Info

Publication number: AU2018414989B2
Application number: AU2018414989A
Authority: AU
Inventors: Chuanzhong CHEN; Huijun YU; Wanli ZHOU
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2018-03-21
Filing date: 2018-12-27
Publication date: 2022-08-11
Anticipated expiration: 2038-12-27
Also published as: CN108569896A; WO2019179194A1; AU2018414989A1; ZA202006545B; CN108569896B

Abstract

Disclosed are a calcium polyphosphate/wollastonite bio-composite ceramic material and a preparation method therefor. The composite ceramic material is made of calcium polyphosphate and wollastonite, and the content of the calcium polyphosphate in mass percentage is 5%-90%; preferably 35%-70%, further preferably 50%-70%, still further preferably 50%, 60% or 70%, and most preferably 50%. A calcium polyphosphate precursor is prepared from calcium dihydrogen phosphate as a raw material by means of a water washing and drying-sintering method. A calcium polyphosphate/wollastonite bio-composite ceramic material is successfully prepared by mixing and sintering the two, and the structure, mechanical properties, biological activity and degradation properties thereof may be adjusted by means of the adjustment of the proportional relationship between the two, thereby preparing a biomaterial with suitable properties according to actual requirements.

Description

CALCIUM POLYPHOSPHATE/WOLLASTONITE BIOLOGICAL COMPOSITE CERAMIC MATERIAL AND PREPARATION METHOD THEREOF BACKGROUND

Technical Field

The present invention belongs to the technical field of biological composite ceramic materials, and particularly relates to a calcium polyphosphate/wollastonite biological composite ceramic material and a preparation method thereof.

Related Art

Biomedical materials are new high-tech materials used for diagnosing, treating, repairing or replacing diseased tissue and organs or improving functions of the diseased tissue and organs of living organisms. Biomedical materials are helpful to improve the life quality and life span of human beings. However, due to the serious aging of the population and the increasing cases of injury, there is a growing demand for biomedical materials, especially biomaterials suitable for bone tissue engineering. The research and development of biomedical materials have become one of the focuses of medical research.

Calcium-phosphate-based biomaterials with a composition similar to that of minerals of bones have good biodegradability, bioactivity and osteoconductivity. Calcium-phosphate based biomaterials may be used for preparing a high-strength functional stent similar to a bone structure through a molding and sintering process. A calcium phosphate product generated after degradation of implant materials may be used as a raw material to be absorbed by osteoblasts for new bone reconstruction. Therefore, calcium-phosphate-based ceramic materials represented by hydroxyapatite (HA) and p-tricalcium phosphate (p-TCP) have become a research hotspot of biomedical materials.

As one of calcium phosphate ceramics, calcium polyphosphate (CPP) has good bioactivity and controllable biodegradability, and no cytotoxicity. Meanwhile, as a bone stent material, CPP has an ideal mechanical property and forms a strong chemical bond with bones. Influenced by a body fluid medium, CPP may partly degrade. Energy released through chain scission caused by degradation may satisfy the needs of cell viability. Degradation products include phosphate, soluble calcium salt, free calcium ions and free phosphorus ions. The products are beneficial to the growth of cells and can be absorbed and utilized by human tissue for growing new tissue. The products may not cause inflammation of surrounding tissue of a host, and have no cytotoxicity, thereby facilitating an osteoconduction effect. Therefore, calcium polyphosphate has become a novel bone tissue engineering repair material emphatically researched by worldwide scholars. However, since there are different opinions on a polymerization degree and a temperature range of crystal transformation of CPP at present, CPP is mainly prepared through a "melting, wire drawing, water quenching, drying, ethanol wet grinding and molding and sintering" process all over the world at present, which easily causes contamination to the material, resulting in the failure to reach purity at medical grade. In addition, in the preparation process, the polymerization reaction and crystal transition temperature are also difficult to control, leading to the failure to obtain ideal material performance, which limits the development of CPP materials in clinical research and application.

Meanwhile, recent studies have shown that wollastonite powder or ceramic has excellent bioactivity and ability of inducing the deposition of a bone-like hydroxyapatite layer in vitro, and silicon is considered as a medium to promote the formation of new bones. The formation of the hydroxyapatite layer facilitates the osteoconduction and bone regeneration of the material as well as the formation of chemical bonding action with soft/hard tissue, which shows that wollastonite is a potential bioactive material with broad application prospects. However, so far there has been no report on the preparation of calcium polyphosphate/wollastonite biological composite ceramic materials.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

SUMMARY

Through long-term technique and practical exploitation, the present invention uses monocalcium phosphate as a raw material and adopts a water washing and drying-sintering method to prepare a calcium polyphosphate precursor. Meanwhile the present invention uses tetraethoxysilane and calcium nitrate terahydrate as raw materials and adopts a sol-gel method to prepare a wollastonite precursor. By mixing and sintering the calcium polyphosphate precursor and the wollastonite precursor, the present invention successfully prepares a calcium polyphosphate/wollastonite biological composite ceramic material. The texture structure, mechanical property, bioactivity and degradation property of the composite ceramic material may be adjusted by adjusting the proportion of the calcium polyphosphate precursor to the wollastonite precursor. Therefore, the biomaterial with proper performance can be prepared according to actual demands.

A first aspect of the present invention provides a calcium polyphosphate/wollastonite biological composite ceramic material, the composite ceramic material is prepared from calcium polyphosphate and wollastonite, and a mass percentage content of the wollastonite is 5-90%, preferably 35-70%, further preferably 50-70%, more further preferably 50%, 60% or 70%, and the most preferably 50%.

Further, the calcium polyphosphate is P type calcium polyphosphate. A second aspect of the present invention provides a preparation method of the above biological composite ceramic material, including the following steps:

Si: with monocalcium phosphate as a raw material, performing water washing, drying, heating and calcining, performing heat preserving for a certain period of time, and performing natural cooling to obtain calcium polyphosphate precursor powder;

S2: preparing a Ca(N03)2 water solution, a Na2SiO3 water solution and a (NH4) 2HP0 4

clear water solution, which are respectively adjusted with ammonia water to a pH of 10.5 11.0; and adding the calcium polyphosphate precursor powder to the Ca(N03)2 water solution, then dropwise adding the Ca(N03)2 water solution mixed with the calcium polyphosphate precursor powder to the Na2SiO3 water solution to generate white precipitates, performing stirring for a certain period of time, performing filtering, performing washing with deionized water and absolute ethyl alcohol, and performing draining and drying to obtain calcium polyphosphate/wollastonite composite precursor powder that is generated in situ;

S3: adding a binder to the calcium polyphosphate/wollastonite composite precursor powder prepared in step S2 for dry pressing; and

S4: performing calcining, heat preserving and then natural cooling on a molded sample to obtain the calcium polyphosphate/wollastonite biological composite ceramic material.

Further, in step S, calcining conditions include: a heating rate of 3-8°C/min (preferably 5°C/min), a calcining temperature of 400-600°C (preferably 500°C), and the heating time of 1-10 h (preferably 10 h).

Further, in step S2, concentrations of the Ca(N03)2 water solution, the Na2SiO3 water solution and the (NH4) 2HP04 clear water solution are 0.5 mol/L.

Further, in step S2, a stirring time is 20-28 h (preferably 24 h).

Further, in step S3, the binder is polyvinyl alcohol, an addition amount is 3-8% (preferably 5%), and dry pressing conditions include: a pressure of 1 Mpa being maintained for 1 min.

Further, in step S4, calcining conditions include: a heating rate of 3-8°C/min (preferably 5°C/min), a calcining temperature of 800-900°C (preferably 850°C), and the heating time of 0.05-5 h (preferably 1.5 h).

A third aspect of the present invention provides another preparation method of the above biological composite ceramic material, including the following steps:

Sl: preparing a calcium polyphosphate precursor: with monocalcium phosphate as a raw material, performing water washing, drying, heating and calcining, performing heat preserving for a certain period of time, and performing natural cooling to obtain the calcium polyphosphate precursor;

S2: preparing a wollastonite precursor: with tetraethoxysilane and calcium nitrate terahydrate as raw materials, by means of a sol-gel method, preparing the wollastonite precursor;

S3: evenly mixing the calcium polyphosphate precursor and the wollastonite precursor in proportion, and adding a binder for dry pressing; and

Further, step S2 of preparing the wollastonite precursor includes the following substeps:

S2.1: performing prehydrolysis on tetraethoxysilane catalyzed by a nitric acid solution in deionized water for 20-60 min, and then adding calcium nitrate terahydrate, and performing stirring for 0.5-2 h to sufficiently dissolve the calcium nitrate terahydrate to obtain clear sol;

S2.2: putting the sol prepared in step S2.1 in a closed container at room temperature to be converted into gel, putting the gel in a constant-temperature water bath at 50-70°C for aging treatment for 2-4 d to obtain semi-dry gel, and performing drying for 18-30 h at 110 130°C to obtain dry gel; and

S2.3: performing ball milling on the dry gel prepared in step S2.2, and performing 200 mesh screening to obtain wollastonite precursor powder with a particle size less than 74 [m.

Further, in step S2.1, a prehydrolysis time is 30 min, a stirring time is 1 h, a concentration of HNO 3 is 2 mol/L, and a molar ratio of tetraethoxysilane to nitric acid to deionized water to calcium nitrate terahydrate is1:(0.02-0.04):(3-5):(0.6-1), preferably 1:0.03:4:0.8.

Further, in step S2.2, a temperature of a constant-temperature water bath is 60°C, an aging treatment time is 3 d, and a drying time is 24 h at 120°C.

A fourth aspect of the present invention provides application of the above composite ceramic material as an implant material.

In another aspect, the present disclosure provides a calcium polyphosphate/wollastonite biological composite ceramic material, wherein the composite ceramic material is prepared from calcium polyphosphate and wollastonite, and a mass percentage content of the wollastonite is 50%-70%;

wherein the calcium polyphosphate is P type calcium polyphosphate; wherein a preparation method of the biological composite ceramic material comprises the following steps:

wherein in step Si, calcining conditions comprise: a heating rate of 3-8°C/min, a calcining temperature of 400-600°C, and a heating time of 1-10 h;

S4: performing calcining, heat preserving and then natural cooling on a molded sample to obtain the calcium polyphosphate/wollastonite biological composite ceramic material;

wherein in step S4, calcining conditions comprise: a heating rate of 3-8°C/min, a calcining temperature of 800-900°C, and a heating time of 0.05-5 h.

In another aspect, the present disclosure provides application of the biological composite material of the invention as an implant material.

Further, the application includes application of the composite ceramic material as an implant material to artificial bone defect repairing.

The present invention uses monocalcium phosphate as a raw material and adopts a water washing and drying-sintering method to prepare a calcium polyphosphate precursor. By mixing and sintering the calcium polyphosphate precursor and the wollastonite precursor, the present invention successfully prepares the calcium polyphosphate/wollastonite biological composite ceramic material. The texture structure, mechanical property, bioactivity and degradation property of the composite ceramic material may be adjusted by adjusting the proportion of the calcium polyphosphate precursor to the wollastonite precursor. Therefore, the biomaterial with proper performance can be prepared according to actual demands. It is verified through tests that after composite ceramic materials prepared in different proportions are soaked in Tris and SBF for 28 d, CPP/WS composite ceramic in different proportions degrades to different extents, and its degradation rate is higher than that of a pure calcium polyphosphate ceramic material; and carbonate-radical-carrying hydroxyapatite is generated on surfaces, which shows that the prepared composite ceramic has good bioactivity and the bioactivity of the CPP/WS composite ceramic is remarkably improved.

6a

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a DSC-TGA profile of monocalcium phosphate, where a heating rate is 10°C/min;

Fig. 2 is an infrared spectrum comparison diagram of monocalcium phosphate and calcium polyphosphate sintered powder;

Fig. 3 is a Raman spectrogram of calcium polyphosphate;

Fig. 4 shows XRD patterns of calcium polyphosphate sintered powder after heat

6b preserving for 1.5 h at different temperatures, where Fig. 4(a) shows the XRD pattern of calcium polyphosphate sintered powder after heat preserving for 1.5 h at 500°C, 600°C, 625°C, 650°C and 700°C, and Fig. 4(b) shows the XRD pattern of calcium polyphosphate sintered powder after heat preserving for 1.5 h at 800°C, 900°C, 930°C, 950°C and 960°C;

Fig. 5 shows NMR spectra at 850°C risen from 500°C at which heat preserving is performed for different periods of time, where the heating time in Fig. 5(a) is 1 h, in Fig. 5(b) 5 h, and in Fig. 5(c) 10 h;

Fig. 6 is a partial enlargement view of the NMR spectrum of "P solid of three types of calcium polyphosphate prepared after heat preserving for 1h, 5 h and 10 h at a temperature of500°C;

Fig. 7 shows the XRD patterns of -CPP with different polymerization degrees prepared after heat preserving for 1 h, 5 h and 10 h at 500°C;

Fig. 8 shows SEM images of three types of calcium polyphosphate prepared after heat preserving for 1 h, 5 h and 10 h at 500°C;

Fig. 9 is a compressive strength variation diagram of three types of calcium polyphosphate prepared after heat preserving for 1h, 5 h and 10 h at 500°C;

Fig. 10 shows the XRD patterns of calcium polyphosphate materials prepared at different calcining temperatures (0°C, 500°C, 600°C, 625°C, 650°C and 700°C);

Fig. 11 shows SEM images of calcium polyphosphate ceramic materials of different crystal forms, where Fig. 11(a) is an SEM image of y-CPP, Fig. 11(b) is an SEM image of y+p-CPP, and Fig. 11(c) is an SEM image of -CPP;

Fig. 12 shows compressive strength of calcium polyphosphate ceramic materials of different crystal forms;

Fig. 13 shows the XRD patterns of a calcium polyphosphate material after heat preserving for different periods of time at 850°C;

Fig. 14 shows SEM images of a calcium polyphosphate material after heat preserving for different periods of time at 850°C, where the heating time in Fig. 14(a) is 5 min, in Fig.

14(b) is 1.5 h, and in Fig. 14(c) is 3 h;

Fig. 15 is a compressive strength diagram of three types of calcium polyphosphate prepared after heat preserving for 5 min, 1.5 h and 3 h at 850°C;

Fig. 16 is a compressive strength variation diagram of calcium polyphosphate with different particle sizes;

Fig. 17 shows the XRD patterns of a CPP/WS biological composite ceramic material obtained after calcining and heat preserving for 1.5 h at 850°C by means of a chemical coprecipitation method, where (a) represents WS, (b) represents a CPP/WS biological composite ceramic material, and (c) represents CPP;

Fig. 18 is a DSC-TGA profile of wollastonite precursor powder dried at 120°C, where a heating rate is 10°C/min;

Fig. 19 shows XRD patterns of wollastonite under different heat-treating systems;

Fig. 20 shows XRD patterns of composite ceramic materials in different proportions after calcining and heat preserving for 1.5 h at 850°C, where curves arrayed in sequence from top to bottom in the patterns respectively represent CPP/WS =100:0, CPP/WS =70:30, CPP/WS =50:50 and CPP/WS =0:100;

Fig. 21 is a weight loss curve graph of calcium polyphosphate/wollastonite biological composite ceramic materials in a Tris buffer solution, the materials being finally prepared by adding calcium polyphosphate and wollastonite in different proportions;

Fig. 22 is a pH variation curve graph of calcium polyphosphate/wollastonite biological composite ceramic materials after soaking in a Tris buffer solution for 28 d, the materials being finally prepared by adding calcium polyphosphate and wollastonite in different proportions;

Fig. 23 shows SEM images of calcium polyphosphate/wollastonite biological composite ceramic materials before and after soaking in a Tris buffer solution for 28 d, the materials being finally prepared by adding calcium polyphosphate and wollastonite in different proportions, where before degradation, (a) p-CPP/WS =100:0; (b) p-CPP/WS =90:10; (c)p

CPP/WS =80:20; (d) p-CPP/WS =70:30; (e) p-CPP/WS =65:35; (f) p-CPP/WS =60:40; (g) p-CPP/WS =50:50; (h) p-CPP/WS =30:70; and (i) p-CPP/WS =0:100;

and after degradation, (ai) p-CPP/WS =100:0; (bi) p-CPP/WS =90:10; (ci) p-CPP/WS =80:20; (di) p-CPP/WS =70:30; (ei) p-CPP/WS =65:35; (fi) p-CPP/WS =60:40; (gi) P CPP/WS =50:50; (hi) p-CPP/WS =30:70; and (ii) p-CPP/WS =0:100;

Fig. 24 is a weight loss variation curve graph of calcium polyphosphate/wollastonite biological composite ceramic materials after soaking in a simulated body fluid (SBF) for 28 d, the materials being finally prepared by adding calcium polyphosphate and wollastonite in different proportions;

Fig. 25 is a pH variation curve graph of calcium polyphosphate/wollastonite biological composite ceramic materials after soaking in a simulated body fluid (SBF) for 28 d, the materials being finally prepared by adding calcium polyphosphate and wollastonite in differentproportions;

Fig. 26 shows SEM images and energy spectrograms of calcium polyphosphate/wollastonite biological composite ceramic materials after degrading in a simulated body fluid (SBF) for 28 d, the materials being finally prepared by adding calcium polyphosphate and wollastonite in different proportions, where (a) p-CPP/WS =100:0; (b) p CPP/WS =90:10; (c) p-CPP/WS =80:20; (d) p-CPP/WS =70:30; (e) p-CPP/WS =65:35; (f) p-CPP/WS =60:40; (g) p-CPP/WS =50:50; (h) p-CPP/WS =30:70; and (i) p-CPP/WS =0:100;

Fig. 27 shows SEM images and energy spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after degrading in a simulated body fluid (SBF) for 1 d, 7 d, 14 d and 28 d, the material being finally prepared in proportion of p-CPP/WS=0:100, where Fig. 27(a) and Fig. 27(ai) are an SEM image and an energy spectrogram after degrading for 1 d respectively, Fig. 27(b) and Fig. 27(bi) are an SEM image and an energy spectrogram after degrading for 7 d respectively, Fig. 27(c) and Fig. 27(ci) are an SEM image and an energy spectrogram after degrading for 14 d respectively, and Fig. 27(d) and Fig. 27(di) are an SEM image and an energy spectrogram after degrading for 28 d respectively;

Fig. 28 shows TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion offp CPP/WS=0:100;

Fig. 29 shows SEM images of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion of p-CPP/WS=30:70, where (a) 0 d; (b) 14 d; (c) 21 d; and (d) 28 d;

Fig. 30 shows TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion offp CPP/WS=30:70;

Fig. 31 shows SEM images of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion of p-CPP/WS=50:50, where (a) 0 d; (b) 14 d; (c) 21 d; and (d) 28 d;

Fig. 32 shows TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion offp CPP/WS=50:50;

Fig. 33 shows SEM images of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion of p-CPP/WS=60:40, where (a) 0 d; (b) 14 d; (c) 21 d; and (d) 28 d;

Fig. 34 shows TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion offp CPP/WS=60:40;

Fig. 35 shows SEM images of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion of p-CPP/WS=65:35, where (a) 0 d; (b) 14 d; (c) 21 d; and (d) 28 d;

Fig. 36 shows TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for different periods of time, the material being finally prepared in proportion offp CPP/WS=65:35;

Fig. 37 shows the XRD patterns of a calcium polyphosphate/wollastonite biological composite ceramic material after soaking in a simulated body fluid (SBF) for 0 d, 3 d and 28 d, the material being finally prepared in proportion of p-CPP/WS=O:100.

DETAILED DESCRIPTION

It should be noted that, the following detailed descriptions are exemplary, and are intended to provide a further description to this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs.

It should be noted that terms used herein are only for the purpose of describing specific implementations and are not intended to limit the exemplary implementations of this application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise. In addition, it should further be understood that terms "comprise" and/or "include" used in this specification indicate that there are features, steps, operations, devices, components, and/or combinations thereof

Embodiments are used to further explain and describe the present invention, but are not intended to limit the present invention.

Example 1

1 Preparation process of calcium polyphosphate ceramic powder

Monocalcium phosphate is taken as a raw material to be washed with deionized water, stirred and dried, and is then poured into a clean crucible (since a calcining temperature is not high, an unglazed ceramic container may be used for containing the monocalcium phosphate; the crucible is put into a batch-type furnace, and a protective measure should be taken at the upper portion of the crucible, so that the crucible is prevented from dirt fallen from the furnace). A temperature is raised to 500°C at a speed of 4°C/min and heat is preserved for 10 h. After the furnace cools down, the raw material is taken out to be ground. At this time, part of the raw material may be attached to a wall of the crucible, and a middle part is taken to prepare calcium polyphosphate ceramic powder precursors with different polymerization degrees.

1.1 Optimization of preparation process of calcium polyphosphate powder

1.1.1 TG curve of monocalcium phosphate

Fig. 1 is a DSC-TGA profile of the monocalcium phosphate. It can be seen from the figure that as the temperature rises, the monocalcium phosphate undergoes a couple of weight loss processes. A DSC curve shows enthalpy variations of these weight loss processes, which means that a decomposition reaction occurs near 147°C and 269°C. A TG curve shows obvious weight loss. The former is caused when monocalcium phosphate loses crystal water while the latter may be caused by a condensation polymerization. The TG curve shows two different times of weight loss processes at this stage. Obvious weight loss occurs between 237.01°C and 278.41°C while no obvious weight loss occurs between 500°C and 800°C. Thus it can be seen that the monocalcium phosphate has a stepwise polymerization property during the condensation polymerization. One time of condensation polymerization occurs near 269°C first and is accompanied by an obvious weight loss process, which means that the monocalcium phosphate rapidly generates a dimer or an oligomer at this stage. The oligomer continues to polymerize at 500-800°C to generate a product with a high polymerization degree accompanied by, however, no obvious weight loss at this stage and scarcely any weight loss especially at 500-600°C, which means that polymerization reaction tends to balance. The polymerization reaction continues when a temperature is further raised. A base line of the DSC curve tends to balance near 800°C, which means that a reaction system tends to balance. Side reactions are intensified when a temperature continues to rise, and the polymerization degree is lowered. In conclusion, the polymerization degree of calcium polyphosphate is more easily improved when polymerization is performed by means of a method of fractional steps. In combination with above discussions, the condensation polymerization of the monocalcium phosphate can be speculated as follows:

A: Ca(H2PO4) 2•xH 20 Ca(H2PO4)2+ xH2O

B: Ca(H2 PO4)2 - CaH2P207+H 20

C: 0- 0 I I n CaH2PA-074 HifO-'P-0-P+0-H +(n-1)H20

0 0

The whole reaction is solid-phase condensation polymerization. It can be seen from reaction equations that the more water is generated in products, the higher the polymerization degree of the monocalcium phosphate will be. A structure of a generated polymer is related to functionality degrees of various monomers participating in the reaction and also related to a ratio of the monomers. When the polymerization reaction at a C stage occurs, a product anhydrous monocalcium phosphate at an A stage and calcium pyrophosphate generated through intramolecular dehydration at a B stage may exist. If anhydrous monocalcium phosphate is not subjected to intramolecular dehydration to generate calcium pyrophosphate completely at the B stage, two types of monomers exist when the polymerization reaction at the C stage occurs, and generated CPP is of a branched structure or a net structure. But in the experiment, it can be seen from the weight loss rate of 8.182% at the B stage in the TG curve that anhydrous CPP has basically all been subjected to intramolecular dehydration to generate calcium pyrophosphate which serves as monomers in the polymerization reaction at the C stage. Therefore, it can be primarily judged that the CPP generated by the reaction in the experiment is a chain polymer.

1.1.2 Infrared spectrum and Raman analysis

Fig. 2 is an infrared spectrum comparison diagram of monocalcium phosphate and calcium polyphosphate sintered powder. It can be seen from Fig. 2 that after the monocalcium phosphate undergoes a reaction at a high temperature, a 3467 cm1 peak corresponding to telescopic vibration of -OH of the monocalcium phosphate basically disappears. It can be primarily judged that the monocalcium phosphate has a condensation polymerization. It can be seen from Fig. 3 that an asymmetrical telescopic vibration peak of an O-P=O functional group appears at about 1278 cm-1 and telescopic vibration peaks of a straight-chain P-O-P functional group appear at about 1173 cm-1 and 713 cm-1, which means that after the monocalcium phosphate has a polymerization reaction at a high temperature, the product has a straight-chain structure, and it is primarily proved that the product is calcium polyphosphate.

1.1.3 XRD phase analysis

Calcium polyphosphate powder is prepared at different temperatures in the experiment and subjected to XRD analysis. A powder X-ray diffraction result is a powerful tool for qualitative analysis of a phase of matter. When X-rays pass through a crystal body, each type of crystalline material has its unique diffraction pattern, and its features can be represented by a crystal boundary distance d of each reflecting surface and a relative strength of reflected rays. Fig. 4(a) and Fig. 4(b) show the XRD patterns of a calcium polyphosphate sintered material after heat preserving for 1.5 h at 500°C, 600°C, 625°C, 650°C, 700°C, 800°C, 900°C, 930°C, 950°C and 960°C. It can be seen from Fig. 4(a) that a y-Ca(PO 3) 2 crystal phase exists as a main part below 600°C, a P-Ca(PO 3) 2 crystal phase appears at 625°C, a P-Ca(PO 3 ) 2 crystal phase exists as a main part at 700-950°C, and P-Ca(PO 3) 2 is wide in existence temperature range and easy to control.

1.2 Influences of different polymerization degrees on performance of calcium polyphosphate ceramic materials

Fig. 5 shows the 3 P-NMR spectrum of calcium polyphosphate. Only a part of the spectrum is listed out in Fig. 6, and affiliations of chemical shifts are noted in the figure. As shown in Fig. 5, Q0 represents a chemical shift of phosphorus atoms in orthophosphoric acid, 0 represents that no oxygen atoms are shared at this time, in this way, Q1 represents a chemical shift of chain end phosphorus atoms, and Q2 represents a chemical shift of phosphorus atoms in a straight-chain structure. As shown in Fig. 6, most parts of the spectrum have no chemical shift of Q, which means that monocalcium phosphate completely reacts. Through a peak area of these chemical shifts, a polymerization degree of calcium polyphosphate can be calculated by the equation of PD=(Q+Q 1 +Q 2)/(Qo+0.5Q 1 ). The polymerization degrees are calculated to be equal to about 20, 25 and 28 in a temperature rise to 850C after heat preserving for 1 h (a), 5 h (b) and 10 h (c) at 500°C respectively. However, it can be seen from Fig. 7 that there is no obvious difference in the three patterns, the crystal form does not change and is of p-CPP, and only strength of three strong peaks slightly changes. It can be seen from Fig. 8 that there is no great difference in surface morphology of three types of calcium polyphosphate ceramic materials with different polymerization degrees. The SEM image of calcium polyphosphate prepared after heat preserving for 10 h at 500°C shows that crystal grain distribution of calcium polyphosphate is finer and more uniform. Fig. 9 shows comparison of measured compressive strength of solid materials prepared after CPP powder with different polymerization degrees is sintered. It can be seen from Fig. 9 that there is a difference in compressive strength of materials with different polymerization degrees, and as polymerization degrees increase, the compressive strength increases.

1.3 Influences of different crystal forms on performance of calcium polyphosphate ceramic materials

It can be seen from Fig. 10 that as a temperature rises, a structure of a phase generated by reaction of monocalcium phosphate changes. y-CPP exists as a main part below 625°C, and p-CPP is gradually formed as a temperature rises. It can be seen from Fig. 11 that as a temperature rises, there is a great change in surface morphology of calcium polyphosphate ceramic materials with different crystal forms. The calcium polyphosphate ceramic materials of a sheet shape gradually become closely connected to have toughness. It can be seen from Fig. 12 that influences of different crystal forms on compressive strength are great, and y CPP <y+p-CPP <-CPP.

1.4 Influences of different heating times on performance of calcium polyphosphate ceramic materials

Fig. 13 shows the XRD patterns of a CPP material after heat preserving for different periods of time at 850°C, and heating times are (a) 5 min, (b) 1.5 h and (c) 3 h respectively. It can be seen through comparison of the three patterns that as the heating time increases, the strongest peak shows increasing intensities and basically there is no difference in XRD peak shape at 5 min and 1.5 h. In combination with Fig. 14 of surface morphology of the material for different heating times, it can be seen that crystal grains are not closely connected at 5 min, crystal grains are closely connected at 1.5 h. When the heat is preserved for 3 h, a thick amorphous region appears between the crystal grains, which causes the incomplete crystallization of the material and the influences on performance of the material. It can be seen through comprehensive comparison that heat preserving for 1.5 h is preferred. It can be seen from Fig. 15 that the compressive strength of the ceramic materials increases as the heating time increases. It can be seen from the above analysis that as the heating time increases, it is the crystallization completeness of the material that changes. The compressive strength of the ceramic materials may be related to the crystallization completeness, and the completer the crystallization is, the lower the internal stress of internal particles of a stent will be, so that the stent presents a good mechanical property outside. Otherwise, the mechanical property of the stent is poor. However, after heat preserving for 3 h, the thick amorphous region appears between the crystal grains, which causes the incomplete crystallization of the material and the influences on performance of the material.

1.5 Selection of particle size of sintered material

It can be seen from Fig. 16 that compressive strength of a ceramic material prepared from ball-milled powder is far higher than compressive strength of a stent prepared within other two particle size ranges. It is mainly caused by different compact degrees of internal combination of particles. In combination with the SEM images in the figure, it can be obviously seen that there are many seams in a stent prepared from a sintered material with a particle size of 80-100 meshes and binding between the particles is poor. Under the action of an external force, the binding will easily fail, which causes damage to the structure of the stent and quite low comprehensive strength. A stent prepared from a sintered material with a particle size of200-300 meshes is slightly better. Ball-milled powder has a large surface area, particles easily make close contact, and probability is provided for close fusion of surfaces of the particles, so that the ball-milled powder has a high mechanical strength.

2. CPP/WS composite precursor powder is prepared in situ by means of a chemical coprecipitation method. A mass ratio of CPP/WS is finally controlled at CPP (100, 90, 80, 70, 65, 60, 50, 30 and 0) and WS (0, 10, 20, 30, 35, 40, 50, 70 and 100). Specifically, a 0.5 mol/L Ca(N03) 2 water solution, a 0.5 mol/L Na2SiO3 water solution and a 0.5 mol/L (NH4) 2HP4 water solution are prepared and adjusted with ammonia water to a pH of 10.5 11.0 respectively. Calcium polyphosphate precursor powder is added to the Ca(N0 3) 2 water solution over stirring. Then the Ca(N0 3) 2 water solution mixed with the calcium polyphosphate precursor powder is dropwise added to the Na2SiO3 water solution to generate white precipitates. Stirring continues for 24 h after feeding is completed. Filtering is performed. Sufficient washing with deionized water and absolute ethyl alcohol is performed. Draining and then drying in an oven in situ are performed to generate the CPP/WS composite precursor powder. A 5% of binder polyvinyl alcohol is added. The mixture is put into a mold with a diameter of 10 mm. A pressure of 1 Mpa is maintained for 1 min. The mixture is pressed to form a cylinder with a diameter of 10 mm x 10 mm. The cylinder is put into a batch-type furnace to be heated to 850°C at a heating rate of 5°C/min and subjected to heat preserving for 1.5 h to obtain CPP/WS powder. Through XRD phase analysis of the calcium polyphosphate/wollastonite biological composite ceramic material in proportion of CPP/WS=1:1 in Fig. 17, it can be seen that the composite powder prepared through the chemical coprecipitation method has a WS phase and a CPP phase.

Example 2

1. Preparation method of calcium polyphosphate precursor the same as Example 1;

2. Preparation of wollastonite (WS) precursor powder: CaO-SiO2 by means of a sol-gel method.

Prehydrolysis is performed on tetraethoxysilane (TEOS) in deionized water under the catalysis action of a proper amount of HNO 3 with a concentration of 2 mol/L for 30 min. Si(OC 2 H) 4 +4H 2 0-SiO 2 +4C 2 HsOH, where a molar weight of the deionized water is four times a molar weight of the tetraethoxysilane, and a molar weight of a nitric acid solution is 0.03 times a molar weight of the tetraethoxysilane. Magnetic stirring is performed. A nearly saturated solution is prepared from corresponding nitrate and then added to the above hydrolysed tetraethoxysilane solution and stirred for 1 h to sufficiently react to form sol. Then the sol is put into a closed container and stood for a certain period of time at room temperature and converted into dry gel. The dry gel is converted into gel, and the gel is put into a constant temperature water bath at 60°C for aging treatment for 72 h. The obtained gel is put into a drying oven to be dried for 24 h at 120°C to obtain dry gel. The dry gel is subjected to ball milling in a ball mill and 200-mesh screening to obtain precursor powder with a particle size smaller than 74 [m.

According to a DSC-TGA profile of wollastonite precursor powder in Fig. 18, a sintering temperature of wollastonite is determined. The precursor powder is put into a thermal treatment furnace for heat preserving for a certain period of time at a certain temperature and a certain heating rate, and then furnace cooling is performed to obtain CaO-SiO 2 powder.

Fig. 19 shows the XRD patterns under different heat treating systems. It can be seen from Fig. 19 that there are obvious amorphous packages in powder X-ray diffraction patterns after heat preserving for 1.5 h at 500°C, which means that powder is in an amorphous form after thermal treatment at 500°C. In the DSC-TGA profile, almost no exothermic peaks appear below 600C. After heat preserving of a sample for 1.5 h at 850°C, obvious WS diffraction peaks occur.

3. Preparation of calcium polyphosphate/wollastonite composite ceramic in different proportions

Ball milling and mixing-dry pressing: Precursor powder in different proportions of CPP (100, 90, 80, 70, 65, 60, 50, 30 and 0) and WS (0, 10, 20, 30, 35, 40, 50, 70 and 100) is subjected to ball milling and even mixing. A 5% of binder polyvinyl alcohol is added. The mixture is put into a mold with a diameter of 10 mm. A pressure of1 Mpa is maintained for 1 min. The mixture is pressed to form a cylinder with a diameter of 10 mm x 10 mm. The cylinder is put into a batch-type furnace to be heated to 850°C at a heating rate of 5°C/min and subjected to heat preserving for 1.5 h. Then natural furnace cooling is performed to prepare the calcium polyphosphate/wollastonite composite ceramic.

Through the XRD patterns of composite ceramic materials in different proportions after calcining and heat preserving for 1.5 h at 850°C in Fig. 20, it can be seen that a WS phase and a CPP phase exist at the same time. WS is wollastonite prepared through a sol-gel method. Meanwhile, in combination of Raman analysis, it can be seen that the composite is a CPP/WS composite.

Example 3

1. Performance test

1.1 The calcium polyphosphate/wollastonite biological composite ceramic material prepared in Example 1 is put into a Tris-HCl solution to be soaked for 28 d, and then its degradation property is tested.

It is found from Fig. 21 that as an addition amount of WS increases, a degradation rate of the composite ceramic material continuously increases, and the degradation rate is 0.2 21%. When the addition amount is 10%, the degradation rate is about 8 times that of a pure CPP ceramic material; and when the addition amount is 100%, the degradation rate is about 70 times that of a pure CPP ceramic material.

Through the pH variation curve of -CPP/WS composite ceramic materials in different proportions in a Tris buffer solution in Fig. 22, it is found that variation trends of pH values of the ceramic materials in different proportions are basically consistent in the soaking process. On the whole, a pH is stabilized within 7.2-8. In the early stage of soaking, when the addition amount is 10% and 20%, a variation rule of a pH is generally similar to a variation rule of a pH of pure CPP, and the pH value increases first, then starts to drop and then is stabilized at about 7.3. When the addition amount increases to 30%, it is obviously found that a pH continuously increases in the first 3 d to reach about 8.2. After the addition amount is greater than 50%, a pH is remarkably higher than a PH of pure CPP and is greater than 7.5. It can be seen in thefigure that after wollastonite is added, pH is kept high, which shows that the addition of the wollastonite improves an ion exchange rate of CPP and the Tris solution.

Fig. 23 shows surface morphology of CPP/WS composite ceramic materials in different proportions before and after degrading in a Tris buffer solution for 28 d. It can be seen from the figure that just like a pure CPP ceramic material, the CPP/WS composite ceramic materials also have many tiny seams and pores in surfaces after being soaked in the Tris buffer solution for 28 d and particles on the surfaces become smaller.

1.2 A degradation property of the calcium polyphosphate/wollastonite biological composite ceramic material prepared in Example 1 is tested after soaking in simulated body fluid (SBF) for 28 d.

It can be seen in Fig. 24 that a weight loss ratio of p-CPP/WS composite ceramic materials in different proportions in the simulated body fluid (SBF) is in an increasing trend on the whole except a ratio of 0:100. The weight loss ratio of p-CPP/WS composite ceramic materials is obviously lower than a weight loss ratio in a Tris buffer solution, which indirectly means that there are still new substances generated in the ceramic materials. The composition of the new substances continues to be analyzed in subsequent infrared spectrogram and surface morphology. It is also observed in the figure that after a ratio increases to 65:35, a generation speed of new substances 21 d later is greater than the weight loss ratio.

It is found in Fig. 25 that variation trends of pH values of ceramic materials in different proportions in the soaking process are basically consistent, and on the whole, a pH is stabilized at about 7.3. In the early stage of soaking, when the addition amount is 10% and 20%, a variation rule of a pH is generally similar to a variation rule of a pH of pure CPP. The pH value increases first, then starts to drop and then is stabilized at about 7. After the addition amount is greater than 50%, a pH continuously increases in the first 3 d to reach about 8, is remarkably higher than a PH of pure CPP and is stabilized at about 7.4. In the soaking process, exchanging first occurs between Ca, Si and other ions and H' in the SBF, H' in the SBF decreases, and basic ions increase, which causes the quick rise of pH. When Ca2+, HPO2-, P0 3-4 , OH-, CO2-3 and other ions in the SBF are enriched on a surface of a sample to form apatite, a pH value of the solution decreases to about 7.4 and is kept unchanged. Generally, a bioactivity of the material has a certain relationship with an ion exchange rate, and the quicker the ion exchange is, the greater a deposition rate of apatite on the surface of the material will be.

According to Fig. 26, as can be analyzed from surface morphology and composition of EDS energy spectrograms of CPP/WS composite ceramic materials in different proportions after soaking in a simulated body fluid (SBF) for 28 d in Fig. 26, surfaces are all covered with deposition layers composed of spherical particles. Part of spherical particles are agglomerated, and cracks appear in the surface deposition layers and are generated in the drying process. It can be seen through the analysis of EDS energy spectrograms that the deposition layers newly formed after soaking mainly include Ca, P, 0 and C. In combination with detection results of infrared spectrograms, it can be seen through analysis that apatite layers are formed on all soaked surfaces in the different proportions, which means that the composite ceramic materials have an ability of inducing the generation of apatite. Moreover, as a proportion of wollastonite increases, an ability of inducing the generation of apatite is enhanced.

It can be seen in Fig. 27 that after soaking for 28 d, a thick layer of deposits composed of spherical particles appear on the surface of the ceramic material. It can be seen through composition analysis of EDS energy spectrograms that the spherical particles in the figure mainly include Ca, P, 0, C and Si. Compared with contents of elements on the surface of the material after soaking for 1 d, 7 d and 14 d, a content of Si element is remarkably reduced. Spherical apatite is a typical morphology of HA.

According to Fig. 28, through the TR-FTIR spectrograms of a calcium polyphosphate/wollastonite biological composite ceramic material in proportion of p CPP/WS=O:100 after soaking in a simulated body fluid (SBF) for different periods of time, it can be seen that P-O functional groups appear at 570 cm-1, 640 cm-1 and 1099 cm-1 positions, and a C-O vibration peak appears at a 1425 cm-1 position. Moreover, O-H telescopic vibration peaks appear at 3430 cm-1 and 1640 cm-1 positions. As a soaking time increases, a Si-O bond gradually gets weak, and strength of a P-0 absorption peak increases.

It can be seen in Fig. 29 that a thick layer of deposits composed of spherical particles appear on the surface of the ceramic material in proportion of p-CPP/WS=30:70 after soaking for 14 d. Furthermore, it can be seen in Fig. 30 that P-0 functional groups appear at 570 cm 1, 640 cm-1 and 1099 cm-1 positions, and a C-0 vibration peak appears at a 1425 cm-1 position. Moreover, O-H telescopic vibration peaks appear at 3430 cm-1 and 1640 cm-1 positions. As a soaking time increases, a Si-O bond gradually gets weak, strength of a P-0 absorption peak increases, and a C-0 vibration peak gets increasingly obvious.

Fig. 33 shows surface morphology of a calcium polyphosphate/wollastonite biological composite ceramic material in proportion of p-CPP/WS=60:40 after soaking in a simulated body fluid (SBF) for different periods of time. As a soaking time increases, deposits on the surface of a ceramic material obviously increase. A thick layer of deposits composed of spherical particles appear on the surface of the ceramic material after soaking for 28 d, and cracks appear in the surface deposit layer after drying. It can be seen in Fig. 34 that after soaking for 28 d, P-0 functional groups appear at 570 cm-1, 640 cm-1 and 1099 cm-1 positions, and a C-O vibration peak appears at a 1425 cm-1 position. Moreover, O-H telescopic vibration peaks appear at 3430 cm-1 and 1640 cm-1 positions. As a soaking time increases, a C-O vibration peak gets increasingly obvious. A weak O-H telescopic vibration peak and a C-O vibration peak appear on the 1 4thd.

Fig. 37 shows the XRD patterns of a calcium polyphosphate/wollastonite biological composite ceramic material in proportion of p-CPP/WS=0:100 after soaking in a simulated body fluid (SBF) for 0 d, 3 d and 28 d. It can be seen in the figure that obvious peaks of hydroxyapatite are found after degrading for 28 d. In combination with infrared spectrograms and SEM images of surface morphology, it is confirmed that a substance depositing on the surface of the composite ceramic material is carbonate-radical-carrying hydroxyapatite.

Actually, a mechanism of forming apatite on a surface in the SBF is similar to that of silico-calcium-based glass. After a material invades an SBF, exchanging occurs between Ca 2

+ on the surface of the material and H' in the SBF. A reaction (1) occurs, and a --Si-OH carrying silicon-rich layer is formed on the surface of the material. Meanwhile, a concentration of OH in the SBF relatively rises, a pH value rises, a reaction (2) occurs, and --Si-0- carrying negative charges is formed on the surface. The material adsorbs positive ions in the SBF, so that energy of a system is reduced. Thus, Ca 2 + in the SBF is adsorbed near the surface of the material, and Ca 2 + further adsorbs P03- 4 , so that ions of a large enough concentration exist on the surface of the material to make apatite deposit. Once apatite nucleates on the surface of the material, the apatite will consume calcium and phosphorus in the SBF to be subjected to spontaneous self-catalysis. It is an amorphous calcium-phosphorus layer that deposits on the surface of the material first. As the soaking time increases and CO2-3 and other impurities mix in, an adjustment and conversion of composition and structure occur to the calcium phosphorus layer, and finally CHA that is thermodynamically stable is formed.

-Si-O-Ca-O-Ca--+2H+= 2--Si-OH + Ca 2+

-Si-OH +0H-= -Si-O-+ H 2 0 (2)

In the present invention, the reason of different crystal morphologies of newly-generated apatite on the surfaces of two types of materials is related to a supersaturation degree of a solution. According to a crystallography principle, the supersaturation degree is the power for crystallization and greatly influences the crystal morphologies. Hydroxyapatite is a hexagonal system, when the supersaturation degree is low, all crystal faces of crystals slowly grow according to a crystal habit, and wormlike crystals with a relatively large length diameter ratio are obtained. For composite biological ceramic, CPP dissolves to release Ca and P to increase the supersaturation degree of calcium and phosphorus in SBF. The high supersaturation degree easily causes the increase of supersaturation differences of all parts on the crystal faces, thereby damaging a sequence of crystal growth and also damaging an integrity of the crystals, and allowing impurities such as C0 3 2 - and Mg 2 + to easily enter the crystals and changing the crystal habit of the crystals. Since the hydroxyapatite becomes homonymous in growth to different extents instead of heterodromous growth according to the crystal habit, the crystals with small granularity and similar to spheres are obtained. As a reaction time increases and other ions mix in, a calcium-phosphorus compound is finally mineralized into bone-like HCA microcrystals from an initial amorphous state through a series of adjustments of composition and structure. The bone-like HCA microcrystals are a thermodynamically stable phase. It can be seen that the formation of a water-containing silicic acid gel layer Si(OH) 4 is quite critical. Thus, for bioglass ceramic, Si has a strong promoting effect on mineralization and activity of the material. A soaking experiment of the SBF shows that within 28 d, the stent material forms these hydroxyapatite microcrystals that are agglomerated into spherical druses, so that surface energy of the material is reduced, and a system is more stable. 3 d later, the spherical druses grow up and are stacked to form a hydroxy-carbonate-apatite (HCA) layer to completely cover the surface of the material, which indicates that the material has a good mineralization ability and a good bioactivity.

To sum up,

1) CPP/WS composite ceramic in different proportions prepared in the present invention all degrade to different extents after soaking for 28 d in Tris and SBF, and its degradation rate is increased compared with that of a pure calcium polyphosphate ceramic material. A layer of carbonate-radical-carrying hydroxyapatite is generated on the surface, which means that the prepared composite ceramic has a good bioactivity and the bioactivity of the CPP/WS composite ceramic is remarkably improved.

2) When an amount of WS reaches 35%, the generation of similar apatite is obviously found after soaking for 14 d in the SBF, and a morphology of the apatite is granular. As a soaking time increases, an amount of the carbonate-radical-carrying hydroxyapatite gradually increases, and a diameter gradually increases. When the soaking time is 14 d and the proportion of the CPP/WS composite ceramic reaches 50:50, carbonate-radical-carrying hydroxyapatite that secondarily nucleates may be found on the surface.

The foregoing descriptions are merely preferred embodiments of this application but are not intended to limit this application. This application may include various modifications and changes for a person skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of this application shall fall within the protection scope of this application.

Claims

CLAIMS What is claimed is:

1. A calcium polyphosphate/wollastonite biological composite ceramic material, wherein the composite ceramic material is prepared from calcium polyphosphate and wollastonite, and a mass percentage content of the wollastonite is 50%-70%;

wherein in step S1, calcining conditions comprise: a heating rate of 3-8°C/min, a calcining temperature of 400-600°C, and a heating time of 1-10 h;

S2: preparing a Ca(N03)2 water solution, a Na2SiO3 water solution and a (NH4) 2HP04 clear water solution, which are respectively adjusted with ammonia water to a pH of 10.5-11.0; and adding the calcium polyphosphate precursor powder to the Ca(N03)2 water solution, then dropwise adding the Ca(N03)2 water solution mixed with the calcium polyphosphate precursor powder to the Na2SiO3 water solution to generate white precipitates, performing stirring for a certain period of time, performing filtering, performing washing with deionized water and absolute ethyl alcohol, and performing draining and drying to obtain calcium polyphosphate/wollastonite composite precursor powder that is generated in situ;

2. The preparation method according to claim 1, wherein the mass percentage content of the wollastonite is 50%, 60% or 70%.

3. The preparation method according to claim 1, wherein in step Sl, calcining conditions comprise: the heating rate of 5°C/min, the calcining temperature of 500°C, and the heating time of 10 h.

4. The preparation method according to claim 1, wherein in step S2, concentrations of the Ca(N3)2 water solution, the Na2SiO3 water solution and the (NH4) 2HP04 clear water solution are 0.5 mol/L, and a stirring time is 20-28 h.

5. The preparation method according to claim 1, wherein in step S2, concentrations of the Ca(N3)2 solution, the Na2SiO3 water solution and the (NH4) 2HP4 clear water solution are 0.5 mol/L, and a stirring time is 24 h.

6. The preparation method according to claim 1, wherein in step S3, the binder is polyvinyl alcohol, an addition amount is 3-8%, and dry pressing conditions comprise: a pressure of 1 Mpa being maintained for 1 min.

7. The preparation method according to claim 1, wherein in step S3, the binder is polyvinyl alcohol, an addition amount is 5%, and dry pressing conditions comprise: a pressure of 1 Mpa being maintained for 1 min.

8. The preparation method according to claim 1, wherein in step S4, calcining conditions comprise: the heating rate of 5°C/min, the calcining temperature of 850°C, and the heating time of 1.5 h.

9. The preparation method according to claim 1, wherein:

in step S, calcining conditions comprise: the heating rate of 5°C/min, the calcining temperature of 500°C, and the heating time of 10 h;

in step S3, the binder is polyvinyl alcohol, an additional amount is 5%, and dry pressing conditions comprise: a pressure of 1 Mpa being maintained for 1 min; and

in step S4, calcining conditions comprise: the heating rate of 5°C/min, the calcining temperature of 850°C, and the heating time of 1.5 h.

10. Application of the biological composite ceramic material according to claim 1 as an implant material.

11. The application according to claim 10, wherein the application comprises application of the composite ceramic material as an implant material to artificial bone defect repairing.