CN114315338B

CN114315338B - Si 3 N 4 /CPP composite ceramic material and preparation method and application thereof

Info

Publication number: CN114315338B
Application number: CN202111668056.0A
Authority: CN
Inventors: 于慧君; 孙博文; 陈传忠
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2021-05-24
Filing date: 2021-12-30
Publication date: 2022-11-22
Anticipated expiration: 2041-12-30
Also published as: CN114315338A

Abstract

The invention belongs to the technical field of biological ceramic materials, and particularly relates to a calcium polyphosphate/silicon nitride composite ceramic material, and a preparation method and application thereof. The method comprises the following steps: first preparing CPP suspension and Si ₃ N ₄ Suspension of Si ₃ N ₄ And adding the suspension into the CPP suspension, uniformly stirring, filtering, pressing and sintering to obtain the Si3N4/CPP composite ceramic material. The composite ceramic material has excellent mechanical property and biological activity, can effectively improve the degradation rate of calcium polyphosphate, can increase the compressive strength, has good biocompatibility, and has wide application prospect as a bone repair material.

Description

Si 3 N 4 CPP composite ceramic material and preparation method and application thereof

Technical Field

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

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

With the technological progress, the living standard of people is continuously improved, the life span of people is prolonged, the phenomenon of aging of the population is aggravated, osteoporosis and bone tissue damage caused by diseases and wounds are concerned by more and more people, and the solution of the academic world and the medical world is urgently needed. Calcium Polyphosphate (CPP) is a Calcium-phosphorus-based ceramic material, and has good biocompatibility, osteoconductivity, biodegradability and mechanical strength, so that the CPP is gradually valued by people and has good development potential in the aspect of bone repair.

Research shows that calcium polyphosphate is different from common organic high molecular polymer in that its main chain structure is not formed by simple covalent bond connection, but is tetrahedron structure [ PO ] ₃ ^- ]The main chain of the polymer of the calcium polyphosphate is mainly-P-O-P-. Calcium polyphosphate used as a tissue engineering scaffold material has gradually become a hot point of research, but the calcium polyphosphate has the problems of slow degradation rate, high brittleness and the like, can be prepared into calcium polyphosphate fibers by adding trace elements and compounded with other materials to improve the performance, has the characteristics of high molecular substances, can adjust the performance of the materials by changing the molecular polymerization degree, the crystal form and the like of the calcium polyphosphate, and can be used as a bone repair, substitution or filling material.

Dan Yongxin and the like prepare a calcium polyphosphate/icariin composite bone substitute biological scaffold through 3D printing, then implant the calcium polyphosphate/icariin composite bone substitute biological scaffold into a white rabbit body to repair ankle bone defects, inject BMSCs cells of the cultured rabbit on the composite scaffold of an experimental group, and use physiological saline for a control group. The observation experiment result shows that the BMSCs cell migration of the experimental group is higher than that of the control group, and the callus generation effect and speed of the experimental group are more excellent than those of the control group, so that the calcium polyphosphate/icariin composite bone substitute biological scaffold prepared by 3D printing can induce stem cells to differentiate into osteoblasts, and has a good bone defect repair effect.

Xue Jinshan, etc. by using a melt spinning method to prepare high-strength composite reinforced CPP fibers, synthesizing fracture internal fixation CPP/polylactic acid (PDLLA) composite materials, implanting the composite materials into a mouse body to perform a series of experiments, and the results show that the CPP-PDLLA composite materials are absorbable biological composite materials with higher safety, and have good biocompatibility and cell non-toxicity. Compared with foreign similar materials, the CPP-PDLLA composite material has great performance advantage and can be better used in clinic.

Yang et al have adopted CPP granule to strengthen the chitosan matrix and prepared the chitosan-based CPP composite material, have studied the tissue reaction and bone conduction ability of calcium polyphosphate as the bone graft material, find that this composite material bone conduction ability and biocompatibility are good in the dog, the degradation rate is relatively slow. The addition of chitosan has no influence on the degradation rate and the osteoconductivity of the CPP particles.

Kandel et al prepared an in vitro biphasic structure consisting of cartilage tissue and CPP. The experimental result shows that after 9 months, the composite implant is fused with adjacent native cartilage and forms fixation by bone growth into the ceramic substrate. The bidirectional structure is beneficial to repairing joint defects, the healing condition is good, and the mechanical property of implanted cartilage is obviously improved.

However, the inventors found that the degradation rate of the existing calcium polyphosphate composite material is difficult to meet the requirements of practical application, and further research is needed to obtain the calcium polyphosphate composite material with high degradation rate and compressive strength.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides Si ₃ N ₄ The composite ceramic material has excellent mechanical property and bioactivity, can effectively improve the degradation rate of calcium polyphosphate, can increase the compressive strength, has good biocompatibility, and has wide application prospect as a bone repair material.

In order to achieve the above object, a first aspect of the present invention provides Si ₃ N ₄ The preparation method of the/CPP composite ceramic material comprises the following specific steps: first preparing CPP suspension and Si ₃ N ₄ Suspension of Si ₃ N ₄ And adding the suspension into the CPP suspension, uniformly stirring, filtering, pressing and sintering to obtain the Si3N4/CPP composite ceramic material.

The second aspect of the invention provides Si obtained by the preparation method ₃ N ₄ the/CPP composite ceramic material.

The third aspect of the present invention provides porous Si ₃ N ₄ The preparation method of the/CPP composite ceramic material comprises the step of preparing Si ₃ N ₄ Based on the preparation method of the CPP composite ceramic material, CPP powder is further processed to obtain a porous CPP material, and then the subsequent steps are carried out.

The fourth aspect of the invention provides porous Si obtained by the preparation method ₃ N ₄ the/CPP composite ceramic material.

The fifth aspect of the present invention provides Si as described above ₃ N ₄ /CPP composite ceramic material and/or porous Si ₃ N ₄ The application of the/CPP composite ceramic material as a degradable implant material;

the application comprises the application of the ceramic material as a degradable implant material in the repair of artificial bone defects.

One or more embodiments of the present invention have at least the following advantageous effects:

si provided by the invention ₃ N ₄ /CPP composite ceramic materialThe composite material is prepared by adopting a simple suspension mixing method, has remarkably excellent mechanical property compared with a CPP material, and when Si is used ₃ N ₄ And the composite proportion of the CPP is 40, the compressive strength reaches 24.88MPa, and the strength is improved by about 35 percent compared with that of a pure CPP ceramic. Si ₃ N ₄ Before the addition amount is 40%, the addition amount is changed with Si ₃ N ₄ The content is increased, the structure of the composite ceramic material is more compact, the uniformity of the material is better, and Si is ₃ N ₄ Can play a role in refining CPP grains.

In addition, the composite material has good biological activity and good biocompatibility, can effectively improve the degradation rate of calcium polyphosphate, and can be rapidly degraded in Tris buffer solution or SBF simulated body fluid.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 shows Ca (H) ₂ PO ₄ ) ₂ The TG-DSC curve of (a);

FIG. 2 shows Ca (H) ₂ PO ₄ ) ₂ And XRD analysis spectrograms of the sintering products at different temperatures;

FIG. 3 is an XRD analysis spectrum of products with different sintering temperatures;

FIG. 4 is P ₂ O ₅ -CaO phase diagram;

FIG. 5 shows Ca (H) ₂ PO ₄ ) ₂ Comparing the infrared spectrum with that of a sintering product CPP;

FIG. 6 is a comparative XRD analysis spectrogram before and after sintering of silicon nitride powder; (a) 850 ℃ and (b) room temperature;

FIG. 7 is an XRD analysis spectrum of the sintering heat preservation of the composite powder and the raw material at 850 ℃ for 1.5 h; (a) CPP, (b) Si ₃ N ₄ ,(c) Si ₃ N ₄ /CPP；

FIG. 8 shows Si in different ratios ₃ N ₄ XRD analysis spectrogram of/CPP composite ceramic sintered at 850 ℃; (a) 10% of Si ₃ N ₄ ,(b) 20％Si ₃ N ₄ ,(c)30％Si ₃ N ₄ ,(d)40％Si ₃ N ₄ ,(e)50％Si ₃ N ₄ ；

FIG. 9 is Si ₃ N ₄ A micro-topography of the/CPP composite ceramic; a1, A2 CPP, B1, B2 10% ₃ N ₄ ,C1、C2 20％ Si ₃ N ₄ ,D1、D2 30％Si ₃ N ₄ ,E1、E2 40％Si ₃ N ₄ ,F1、F2 50％Si ₃ N ₄ ；

FIG. 10 shows Si in different ratios ₃ N ₄ The weight change of the/CPP composite ceramic degraded in the Tris solution;

FIG. 11 shows Si in different proportions ₃ N ₄ The pH value of the/CPP composite ceramic degraded in a Tris solution is changed;

FIG. 12 shows Si in different ratios ₃ N ₄ The infrared spectrum of the degradation of the/CPP composite ceramic in a Tris solution; (a) no soak, (b) 10% of Si ₃ N ₄ ,(c)20％Si ₃ N ₄ ,(d)30％Si ₃ N ₄ ,(e)40％Si ₃ N ₄ ，(f)50％Si ₃ N ₄ ；

FIG. 13 shows Si in different ratios ₃ N ₄ The microcosmic appearance of the/CPP composite ceramic degraded in Tris solution; a1, A2% ₃ N ₄ , B1、B2 20％Si ₃ N ₄ ,C1、C2 30％Si ₃ N ₄ ,D1、D2 40％Si ₃ N ₄ ,E1、E2 50％Si ₃ N ₄ ；

FIG. 14 shows Si in different ratios ₃ N ₄ Weight change of the/CPP composite ceramic degraded in the SBF solution;

FIG. 15 shows Si in different ratios ₃ N ₄ pH change of the composite ceramic in SBF solution;

FIG. 16 shows Si in different ratios ₃ N ₄ The infrared spectrum of the degradation of the/CPP composite ceramic in the SBF solution; (a) no soak, (b) 10% of Si ₃ N ₄ ,(c)20％Si ₃ N ₄ ,(d)50％Si ₃ N ₄ ,(e)50％Si ₃ N ₄ ；

FIG. 17 is a variationProportional Si ₃ N ₄ XRD analysis spectrogram of the/CPP composite ceramic after 28 days of degradation in SBF; (a) CPP, (b) 10% by weight of Si ₃ N ₄ ,(c)20％Si ₃ N ₄ ,(d)30％Si ₃ N ₄ ,(e)40％Si ₃ N ₄ ,(f)50％Si ₃ N ₄ ；

FIG. 18 shows Si in different proportions ₃ N ₄ The micro-morphology of the/CPP composite ceramic degraded in the SBF solution; a1, A2% ₃ N ₄ ,B1、B2 20％Si ₃ N ₄ ,C1、C2 30％Si ₃ N ₄ ,D1、D2 40％Si ₃ N ₄ ,E1、E2 50％Si ₃ N ₄ ；

FIG. 19 shows Si in different ratios ₃ N ₄ The compressive strength of the/CPP composite ceramic degraded in the SBF solution is changed;

FIG. 20 shows porous Si in different ratios ₃ N ₄ The compressive strength of the/CPP composite ceramic;

FIG. 21 shows porous Si ₃ N ₄ The micro-morphology of the/CPP composite ceramic; a1, A2 30% v stearic acid, B1, B2% v stearic acid.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As described in the background art, the degradation rate of the existing calcium polyphosphate composite material is difficult to meet the requirements of practical application, and further research needs to be performed to obtain the calcium polyphosphate composite material with high degradation rate and compressive strength.

In order to solve the above technical problems, a first aspect of the present invention provides Si ₃ N ₄ The preparation method of the/CPP composite ceramic material comprises the following specific working procedures: first preparing CPP suspension and Si ₃ N ₄ Suspension of Si ₃ N ₄ And adding the suspension into the CPP suspension, uniformly stirring, filtering, pressing and sintering to obtain the Si3N4/CPP composite ceramic material.

In the invention, si is mixed with ₃ N ₄ Compounded with CPP material, si ₃ N ₄ The crystal grain structure, the biological activity and the mechanical property of the CPP can be obviously improved, and the specific expression is as follows:

(1)Si ₃ N ₄ can play a role of a reinforcing phase in the sintering process, so that the bonding strength of the material is improved.

(2)Si ₃ N ₄ The CPP crystal grain refining function can be achieved, the crystal size of the CPP is integrally reduced, and the CPP can be better played;

(3)Si ₃ N ₄ the balance of dissolution and precipitation of calcium and phosphorus ions in the CPP can be changed, so that the degradation rate is greater than the deposition rate, the degradation process of the CPP ceramic is accelerated, and the degradation performance is improved.

Therefore, the present invention combines Si ₃ N ₄ Si obtained after CPP loading ₃ N ₄ Compared with CPP, the CPP composite ceramic material has excellent mechanical property and bioactivity, can effectively improve the degradation rate of calcium polyphosphate, can increase the compressive strength, and has excellent biocompatibility.

The preparation method of the CPP suspension comprises the following steps: with Ca (H) ₂ PO ₄ ) ₂ The powder is used as a raw material, is sintered by adopting a solid-phase sintering method, is cooled to room temperature along with a furnace and is taken out, and the pre-sintering process of the material is completed;

and pouring the pre-sintered material into a mortar for coarse grinding, adding alcohol and ball-milling by using a ball mill to obtain CPP powder, and pouring the CPP powder into deionized water to be stirred to form CPP suspension.

The conditions of the solid-phase sintering method are as follows: heating from room temperature to 500-600 ℃ at the heating rate of 4 ℃/min, and preserving heat for 10-15h; under the heating temperature and the heat preservation time, the gamma + beta type calcium polyphosphate can be obtained, the heating temperature is lower than the heating temperature, or the heat preservation time is shorter than the heat preservation time, only the gamma type calcium polyphosphate can be obtained, and the gamma + beta type calcium polyphosphate is more beneficial to improving the tensile strength and the dissolution rate.

Further, removing powder on the part, which is in contact with the bottom of the porcelain boat, of the sintered material, and selecting a middle part of the sintered material to pour into a mortar for coarse grinding; the purpose is to improve the purity of the material and reduce impurities.

Furthermore, the ball milling time is 1-2h.

Further, drying after ball milling, and sieving with a 200-mesh sample sieve to obtain screened CPP powder.

In one or more embodiments of the present invention, the Si is ₃ N ₄ The preparation method of the suspension comprises the following steps: mixing Si ₃ N ₄ Dissolving the powder in a dispersant, and uniformly stirring to obtain Si ₃ N ₄ A suspension;

si used in the invention ₃ N ₄ The powder is 500-600nm ultrafine powder which can be fully contacted with CPP for close compounding, but the powder with small particle size has high surface energy and is easy to agglomerate, and the key for preparing the powder ceramic composite material is that the nanoscale powder can be fully dispersed and uniformly mixed with other powder, so that the invention can be used for preparing Si ₃ N ₄ The powder was subjected to dispersion treatment. In order to achieve the effect, the invention selects the polyethylene glycol as the dispersant, and the polyethylene glycol can effectively promote Si ₃ N ₄ And (4) dispersing the powder.

Wherein, the molecular weight of the polyethylene glycol can influence the dispersion effect, and when the molecular weight is 4000, the dispersion effect is optimal;

besides the influence of molecular weight, pH and the content of the dispersant also influence the dispersion effect, and Si with good dispersibility and agglomeration resistance can be obtained by adjusting the pH and reasonably setting the mass content of the dispersant ₃ N ₄ (ii) a suspension.

Further, the amount of the dispersant added is Si ₃ N ₄ 0.4-0.6% of the powder;

further, the pH is adjusted to 9-10 during the stirring process, the solution for adjusting the pH is not limited, and the solution is alkaline, and the pH is preferably adjusted by sodium hydroxide in view of cost and feasibility;

stirring uniformly, and performing ultrasonic treatment for 30-40min to obtain Si ₃ N ₄ The suspension was well dispersed.

In one or more embodiments of the present invention, si ₃ N ₄ Is added in an amount of Si ₃ N ₄ 10-50% of the mass of the/CPP composite material;

preferred Si ₃ N ₄ Is added in an amount of Si ₃ N ₄ 25-45% of the mass of the/CPP composite material;

further preferred is Si ₃ N ₄ Is added in an amount of Si ₃ N ₄ 35-45% of the mass of the/CPP composite material;

most preferably 40%, at which the ceramic material particles are finest and most uniform, and compressive strength and dissolution rate are best, below which percentage the ceramic material particles are coarse, above which individual coarse-sized particles appear in the finer particles, affecting overall uniformity.

In one or more embodiments of the present invention, si ₃ N ₄ Slowly adding the suspension into the CPP suspension for multiple times, stirring while adding, keeping stirring for 30-40min, then carrying out centrifugal treatment, carrying out washing, drying and 200-mesh sieve sieving to obtain composite powder, and then mixing the composite powder with the adhesive according to the proportion of 5g: (0.5-2) mL of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder; and (4) finishing the dry pressing forming process, and sintering in a resistance furnace to obtain the Si3N4/CPP composite ceramic material. Wherein, the sintering process comprises the steps of firstly heating from room temperature to 400 ℃ according to the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃, preserving heat for 1.5h, and furnace-cooling to room temperature.

The further powder to binder ratio was 5g: adding 5% polyvinyl alcohol aqueous solution as a binder into 1mL of the solution;

the second aspect of the invention provides a Si3N4/CPP composite ceramic material obtained by the preparation method.

The third aspect of the invention provides a preparation method of a porous Si3N4/CPP composite ceramic material, which is characterized in that Si3N4/CPP composite powder is further processed on the basis of the preparation method of the Si3N4/CPP composite ceramic material, and the preparation method of the porous Si3N4/CPP material comprises the following steps:

mixing Si3N4/CPP composite powder with a stearic acid pore-foaming agent according to a proportion, wherein the proportion of the stearic acid pore-foaming agent is 10-50 Vol; then, uniformly mixing for 20min by using a vortex mixer, and then mixing according to the ratio of powder to the binder of 5g: (0.5-2) mL of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder; after the uniform mixing, the powder is put into a die for dry pressing and forming, and the obtained blank is put into a resistance furnace for sintering. Wherein, the sintering process comprises the steps of firstly heating from room temperature to 400 ℃ according to the heating rate of 4 ℃/min, preserving heat for 2h, then heating to 850 ℃, preserving heat for 1.5h, and furnace-cooling to room temperature.

Preferably, the proportion of the stearic acid pore-forming agent is 15-45Vol%;

further, the proportion of the stearic acid pore-forming agent is 25-35Vol%;

the most preferred proportion of stearic acid porogen is 30Vol%;

further, the particle size of the stearic acid pore-foaming agent is selected from 50-80 meshes and 80-120 meshes;

the further powder to binder ratio was 5g: adding 1mL of polyvinyl alcohol aqueous solution with the mass fraction of 5% as a binder;

further, pressing and forming on a hydraulic machine according to a method of keeping the pressure at 1MPa for 1 min;

further, the heating rate is 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the heat preservation is carried out for 2h, then the temperature is heated to 850 ℃, the heat preservation is carried out for 1.5h, the temperature is cooled to the room temperature along with the furnace, and the final sintering process of the material is completed.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

Example 1

Preparation of CPP suspension:

raw material Ca (H) ₂ PO ₄ ) ₂ The powder is put into a clean corundum porcelain boat, a cover is covered to prevent furnace dust from falling to pollute the powder in the sintering process and leave a plurality of gaps for facilitating gas circulation, the powder is heated from room temperature to 500 ℃ at the heating rate of 4 ℃/min in a resistance furnace by adopting a solid-phase sintering method, the temperature is kept for a period of time, and the powder is taken out after being cooled to the room temperature along with the furnace, so that the pre-sintering process of the material is completed. And taking the white blocky solid obtained by sintering out of the porcelain boat, paying attention to the fact that part of powder in contact with the bottom of the porcelain boat needs to be removed, selecting a middle part of material, pouring the middle part of material into a mortar for coarse grinding, then adding alcohol, carrying out ball milling for 1h by using a ball mill, drying, sieving by using a 200-mesh sample sieve to obtain pre-sintered CPP powder, and pouring the CPP powder into deionized water to be stirred to form CPP suspension.

Example 2

Si ₃ N ₄ Preparation of the suspension:

PEG4000 granular polyethylene glycol is selected for the experiment, and the addition amount is Si ₃ N ₄ 0.5 percent of the powder mass, slowly dripping sodium hydroxide solution on a magnetic stirrer while stirring to adjust Si ₃ N ₄ The pH value of the powder suspension is between 9 and 10, and then ultrasonic treatment is carried out for 30min to ensure that the suspension is well dispersed.

Example 3

Si ₃ N ₄ Preparation of CPP composite ceramic powder:

mixing the uniformly mixed Si ₃ N ₄ The suspension is slowly added into the CPP suspension prepared in advance for a plurality of times, si ₃ N ₄ The compounding ratio of the Si-CPP and the CPP is 5:5, stirring is carried out while adding, stirring is kept for 30min, then centrifugal treatment is carried out, and the Si is obtained through operations of washing, drying and 200-mesh sieving ₃ N ₄ the/CPP composite ceramic powder.

Example 4

Si ₃ N ₄ Preparation of/CPP composite ceramic powder:

mixing the uniformly mixed Si ₃ N ₄ The suspension is slowly added into the CPP suspension prepared in advance for a plurality of times, si ₃ N ₄ The compounding ratio of the silicon-containing silicon oxide and CPP is 4:6, stirring is carried out while adding, stirring is kept for 30min, then centrifugal treatment is carried out, and the Si is obtained by washing, drying and sieving with a 200-mesh sieve ₃ N ₄ the/CPP composite ceramic powder.

Example 5

Si ₃ N ₄ Preparation of/CPP composite ceramic powder:

mixing the uniformly mixed Si ₃ N ₄ The suspension is slowly added into the CPP suspension prepared in advance for a plurality of times, si ₃ N ₄ The compounding ratio of the Si-CPP and the CPP is 3:7, stirring is carried out while adding, stirring is kept for 30min, then centrifugal treatment is carried out, and the Si is obtained through operations of washing, drying and 200-mesh sieving ₃ N ₄ the/CPP composite ceramic powder.

Example 6

Si ₃ N ₄ Preparation of/CPP composite ceramic powder:

mixing the uniformly mixed Si ₃ N ₄ The suspension is slowly added into the CPP suspension prepared in advance for a plurality of times, si ₃ N ₄ The compounding ratio of the silicon-containing silicon oxide and CPP is 2:8, stirring is carried out while adding, stirring is kept for 30min, then centrifugal treatment is carried out, and the Si is obtained by washing, drying and sieving with a 200-mesh sieve ₃ N ₄ the/CPP composite ceramic powder.

Example 7

Si ₃ N ₄ Preparation of/CPP composite ceramic powder:

mixing the uniformly mixed Si ₃ N ₄ The suspension is slowly added into the CPP suspension prepared in advance for a plurality of times, si ₃ N ₄ The compounding ratio of the silicon-containing silicon oxide and CPP is 1:9, stirring is carried out while adding, stirring is kept for 30min, then centrifugal treatment is carried out, and the Si is obtained by washing, drying and sieving with a 200-mesh sieve ₃ N ₄ the/CPP composite ceramic powder.

Example 8

Porous Si ₃ N ₄ The preparation method of the/CPP composite ceramic material comprises the following steps:

si prepared in example 3 ₃ N ₄ the/CPP composite ceramic powder is mixed with 10Vol% of stearic acid pore-foaming agent, the particle size of the stearic acid pore-foaming agent is selected from 50-80 meshes and 80-120 meshes, then the stearic acid pore-foaming agent and the stearic acid pore-foaming agent are uniformly mixed for 20min by using a vortex mixer, and then a proper amount of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder. After uniform mixing, the powder is put into a self-made stainless steel mold, and dry-method compression molding is carried out on a hydraulic press according to the method of 1MPa of pressure and 1min of pressure maintaining. And putting the obtained cylindrical blank into a resistance furnace for sintering. The sintering speed is 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the heat preservation is carried out for 2h, then the temperature is heated to 850 ℃, the heat preservation is carried out for 1.5h, and the material is cooled to the room temperature along with the furnace, thus completing the final sintering process of the material.

Example 9

si prepared in example 3 ₃ N ₄ the/CPP composite ceramic powder is mixed with 20Vol% of stearic acid pore-foaming agent, the particle size of the stearic acid pore-foaming agent is selected from 50-80 meshes and 80-120 meshes, then the stearic acid pore-foaming agent and the stearic acid pore-foaming agent are uniformly mixed for 20min by using a vortex mixer, and then a proper amount of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder. After uniform mixing, the powder is put into a self-made stainless steel mold, and dry-method compression molding is carried out on a hydraulic press according to the method of 1MPa of pressure and 1min of pressure maintaining. And putting the obtained cylindrical blank into a resistance furnace for sintering. The sintering speed is 4 DEG CAnd/min, firstly heating to 400 ℃ from room temperature, preserving heat for 2h, then heating to 850 ℃, preserving heat for 1.5h, and cooling to room temperature along with the furnace to finish the final sintering process of the material.

Example 10

si prepared in example 3 ₃ N ₄ the/CPP composite ceramic powder is mixed with 30Vol% of stearic acid pore-foaming agent, the particle size of the stearic acid pore-foaming agent is selected from 50-80 meshes and 80-120 meshes, then the stearic acid pore-foaming agent and the stearic acid pore-foaming agent are uniformly mixed for 20min by using a vortex mixer, and then a proper amount of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder. After uniform mixing, the powder is put into a self-made stainless steel mold, and dry-method compression molding is carried out on a hydraulic press according to the method of 1MPa of pressure and 1min of pressure maintaining. And putting the obtained cylindrical blank into a resistance furnace for sintering. The sintering speed is 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the heat preservation is carried out for 2h, then the temperature is heated to 850 ℃, the heat preservation is carried out for 1.5h, and the material is cooled to the room temperature along with the furnace, thus completing the final sintering process of the material.

Example 11

si prepared in example 3 ₃ N ₄ the/CPP composite ceramic powder is mixed with 40Vol% of stearic acid pore-foaming agent, the particle size of the stearic acid pore-foaming agent is selected from 50-80 meshes and 80-120 meshes, then the stearic acid pore-foaming agent and the stearic acid pore-foaming agent are uniformly mixed for 20min by using a vortex mixer, and then a proper amount of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder. After uniform mixing, the powder is put into a self-made stainless steel mold, and dry-method compression molding is carried out on a hydraulic press according to the method of 1MPa of pressure and 1min of pressure maintaining. And putting the obtained cylindrical blank into a resistance furnace for sintering. The sintering speed is 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the temperature is preserved for 2h, then the temperature is raised to 850 ℃, the temperature is preserved for 1.5h, and the material is cooled to the room temperature along with the furnace, thereby completing the final sintering process of the material.

Example 12

si prepared in example 3 ₃ N ₄ the/CPP composite ceramic powder is mixed with a stearic acid pore-forming agent with the mass percent of 50Vol%, the particle size of the stearic acid pore-forming agent is selected from 50-80 meshes and 80-120 meshes, then the stearic acid pore-forming agent and the stearic acid pore-forming agent are uniformly mixed for 20min by using a vortex mixer, and then a proper amount of polyvinyl alcohol aqueous solution with the mass percent of 5% is added as a binder. After uniform mixing, the powder is put into a self-made stainless steel mold, and dry-method compression molding is carried out on a hydraulic press according to the method of 1MPa of pressure and 1min of pressure maintaining. And putting the obtained cylindrical blank into a resistance furnace for sintering. The sintering speed is 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the heat preservation is carried out for 2h, then the temperature is raised to 850 ℃, the heat preservation is carried out for 1.5h, the temperature is cooled to the room temperature along with the furnace, and the final sintering process of the material is completed.

And (3) performance testing:

1. characterization of the CPP powder:

(1)Ca(H ₂ PO ₄ ) ₂ thermogravimetric and differential thermal analysis of

Calcium dihydrogen phosphate Ca (H) ₂ PO ₄ ) ₂ The thermogravimetric curve and the differential scanning calorimetry curve of (a) are shown in fig. 1. As can be seen from the figure, the weight of the powder undergoes three large changes with a constant increase in temperature. Firstly, the weight loss of the powder is 4.785% from the initial temperature rise to the range of 147.02 ℃, namely, the stage A in the figure corresponds to the volatilization of calcium dihydrogen phosphate crystal water and the endothermic peak generated at 146.94 ℃ on a DSC curve; then, in the range of 250.66-273.07 ℃, namely the stage B in the figure, the weight loss is 8.508%, the stage is corresponding to the calcium dihydrogen phosphate powder losing the crystal water to generate an intramolecular dehydration condensation process, two hydroxyl groups (-OH) remove one water molecule, and calcium dihydrogen pyrophosphate (CaH) is formed ₂ P ₂ O ₇ ) Corresponding to an endothermic peak at 267.74 ℃ on the DSC curve; the third segment weight loss is slowly carried out at 273.07 ℃, namely the C stage in the figure, the weight tends to be stable after the temperature reaches 500 ℃, the corresponding reaction process is that calcium dihydrogen pyrophosphate molecules are continuously dehydrated, one water molecule is removed from the remaining two hydroxyl groups (-OH), the calcium polyphosphate CPP long-chain polymer material is formed, and the calcium polyphosphate CPP long-chain polymer material extends to 535.61 ℃ corresponding to the DSC curveThe falling curve of (c). Therefore, the presintering temperature set in the experiment should be in the calcium polyphosphate forming stage, 500 ℃ is selected as the heat preservation temperature for presintering the powder in the experiment, and presintering precursor powder with different polymerization degrees is obtained by adjusting the heat preservation time.

The powder sintering reaction equation is as follows:

A:Ca(H ₂ PO ₄ ) ₂ ·xH ₂ O→Ca(H ₂ PO ₄ ) ₂ +xH ₂ O (3-1)

B:Ca(H ₂ PO ₄ ) ₂ →CaH ₂ P ₂ O ₇ +H ₂ O (3-2)

C:nCaH ₂ P ₂ O ₇ →CPP+(n-1)H ₂ O (3-3)

(2) XRD phase analysis

To explore Ca (H) ₂ PO ₄ ) ₂ Sintering at different temperatures to obtain product types, and performing XRD phase analysis on powder obtained by sintering at 500-950 ℃ for the same time (10 h) and cooling in air. As can be seen from FIGS. 2 and 3, calcium dihydrogen phosphate at room temperature has been converted to calcium polyphosphate, ca (H) at 500 deg.C ₂ PO ₄ ) ₂ Substantially disappears, resulting in a diffraction peak of CPP. And after 10h of heat preservation, the powder structure corresponds to two different crystal forms, namely gamma-CPP (JCPDS # 50-0584) and beta-CPP (JCPDS # 77-1953), which shows that the crystal form transformation process from gamma-CPP to beta-CPP is performed at 500 ℃. When the temperature reaches the range of 550-600 ℃, the crystal form mainly exists in a beta-CPP crystal form, the crystal form transformation process tends to be complete, and the exothermic peaks at about 554 and 601 ℃ can be presumed to correspond to the crystal form transformation process by combining the partial analysis of the differential thermal curve shown in figure 1. When the temperature is within the range of 650-950 ℃, the crystal form is completely a beta-CPP crystal form, wherein the strongest peak corresponds to the characteristic diffraction peak of a (022) crystal face, which indicates that the calcium polyphosphate mainly grows along the (022) crystal face. The result shows that the temperature range of the beta-CPP obtained by the sintering experiment is wider, the stable existing temperature range is large, and the controllable pure beta-CPP can be prepared conveniently. In view of the factAnd (5) testing the stable existence of the sintering product and the unification of the preparation process, and selecting 850 ℃ as the final sintering temperature.

According to P shown in FIG. 4 ₂ O ₅ The CaO phase diagram can conclude that calcium polyphosphate CPP (calcium to phosphorus ratio 0.5, corresponding to CaO: P) ₂ O ₅ = 1:1) in the figure, namely at CP, liquid phase is slowly generated when the temperature rises to about 750 ℃ of eutectic line, and the liquid phase can be completely melted when the temperature reaches more than 980 ℃. In consideration of the preparation and forming process of the sample in the experiment, a small amount of CPP powder is melted to form a glassy substance, so that the mechanical property of the material can be improved, but if the sintering temperature is too high, the powder melting can damage the shape of the formed sample, influence the material property and be not beneficial to subsequent experimental tests.

(3) Infrared spectroscopic analysis

Infrared spectroscopy refers to the analysis and identification of molecules of a substance by irradiating the substance with infrared rays of different wavelengths, which are absorbed by the molecules due to their unique composition and structure, corresponding to certain specific wavelengths. Infrared spectroscopic analysis can be used to study the structure and chemical bonds of the molecule, the curve in FIG. 5 being Ca (H) ₂ PO ₄ ) ₂ Comparison of the infrared spectra of the powder and the sintered product CPP. As can be seen, ca (H) ₂ PO ₄ ) ₂ The product (shown by red line) after high-temperature sintering is 680-790 cm ^-1 The oscillating peaks of the linear chain P-O-P appear jagged at the range and are at 1120 and 1311cm ^-1 Generates a stretching vibration peak of O-P = O at 3467cm ^-1 The peak of stretching vibration of hydroxyl (-OH) has substantially disappeared, and is located at 3237, 2980, 2393, 2294 and 1664cm ^-1 The disappearance of the peaks at the nearby positions indicates that Ca (H) was caused by sintering ₂ PO ₄ ) ₂ The powder was transformed, the hydroxyl group in the structure disappeared, the sintered product was of a straight chain structure and a polycondensation reaction occurred, thereby proving that the product is CPP.

2、Si ₃ N ₄ Performance analysis of/CPP composite ceramic Material

(1)Si ₃ N ₄ Properties of the powder:

FIG. 6 shows Si prepared in example 2 ₃ N ₄ The powder is at 85XRD phase analysis patterns after 0 ℃ sintering (line a) and at normal temperature (line b). It can be seen that the powder Si ₃ N ₄ The phase peak at high temperature is increased compared with the normal temperature strength, but the positions of the three strong peaks are not obviously changed, which proves that the high temperature stability is better. Si ₃ N ₄ The corresponding PDF card is JCPDS #33-1160, and the crystal form corresponds to beta-type Si ₃ N ₄ . The material powder contains a small part of free Si in the preparation process, the proportion of the free Si is less than 0.01 percent, the corresponding peak in the material phase after the sintering at 850 ℃ is not obvious, and the influence can be ignored.

(2)Si ₃ N ₄ Phase analysis of/CPP composite ceramic material

FIG. 7 is the XRD curve of the ceramic after sintering and holding the temperature at 850 ℃ for 1.5h of the prepared composite powder and the comparison result of the two raw materials. It can be seen that Si is shown by the curve (c) ₃ N ₄ The diffraction peak of the/CPP composite material is low in intensity compared with those of the two raw materials (a) and (b), and Si ₃ N ₄ The crystal phase is obvious, the peak type accords with the diffraction peak of PDF card JCPDS #33-1160, and the crystal phase corresponds to high-temperature beta type Si ₃ N ₄ The presence of two-phase peak overlap at the 23.4 °,27.0 °,33.5 °,36.0 °,38.95 °,41.3 ° and 49.8 ° positions in curve (c) indicates the formation of Si ₃ N ₄ a/CPP composite ceramic. In the figure Si ₃ N ₄ Compared with a pure CPP material, the diffraction peak of the CPP composite material is wider, the peak intensity of partial CPP is reduced or even disappears, and Ca appears ₂ P ₂ O ₇ And Ca ₄ P ₆ O ₁₉ Two calcium phosphorus compounds, indicating the addition of Si ₃ N ₄ Make CPP produce decomposition, si ₃ N ₄ The decomposition speed of the CPP can be accelerated. FIG. 8 shows different ratios of Si ₃ N ₄ XRD analysis pattern of/CPP composite ceramic sintered at 850 ℃. As can be seen from the figure, in the composite ceramic material, si is accompanied by Si ₃ N ₄ The content is increased, the intensity of the corresponding diffraction peak is increased, the peak intensity of the CPP phase is relatively reduced, and Ca generated by the decomposition of the CPP is relatively reduced ₂ P ₂ O ₇ And Ca ₄ P ₆ O ₁₉ The peak intensity of (A) gradually increases, indicating that Si is present ₃ N ₄ The larger the content of (A), the more the decomposition process of CPP can be promoted.

(3)Si ₃ N ₄ Compressive strength analysis of/CPP composite ceramic material

To explore Si ₃ N ₄ The mechanical property of the composite ceramic prepared after the addition is that different Si is selected ₃ N ₄ The ceramic samples were subjected to the compressive strength test in percentage by mass, and the results are shown in table 1. As can be seen from the table, the strength of the prepared composite ceramic is higher than that of the composite ceramic without adding Si ₃ N ₄ Pure CPP ceramic of, si ₃ N ₄ The addition of (2) can improve the compressive strength of calcium polyphosphate ceramics, which shows that Si ₃ N ₄ Plays a role of a reinforcing phase in the CPP sintering process, and improves the bonding strength of the material. With Si ₃ N ₄ The content is increased, the compressive strength of the composite ceramic is increased firstly and then reduced, and Si with the mass fractions of 10%, 20% and 30% is added ₃ N ₄ When the CPP is used, the strength is respectively 19.74MPa, 21.12MPa and 22.64MPa, and the mechanical strength is respectively improved by 6.99 percent, 14.47 percent and 22.71 percent compared with the mechanical strength of a pure CPP; when Si is present ₃ N ₄ The composite proportion of/CPP is 40, the highest compressive strength reaches 24.88MPa, and the strength is improved by 34.85 percent compared with that of pure CPP; when Si is present ₃ N ₄ When the content is increased to 50%, the compressive strength is decreased to 21.09MPa, probably because of Si ₃ N ₄ If the content is too high, particle segregation growth can occur, so that the structure of the material is changed, the uniformity of the material is reduced, and the bonding strength of the material is reduced.

TABLE 1 Si in different proportions ₃ N ₄ Compressive strength of/CPP composite ceramic material

(4)Si ₃ N ₄ Microcosmic appearance analysis of/CPP composite ceramic material

FIG. 9 shows Si in different ratios ₃ N ₄ Surface micro-topography of/CPP composite ceramic Material, wherein A shows the topography of pure CPP, and B to F show 10% by weight of Si ₃ N ₄ To 50% of Si ₃ N ₄ The topography of (1). As can be seen from the figure, the pure CPP ceramic material has different particle shapes and uneven size; adding 10% of Si ₃ N ₄ And 20% of Si ₃ N ₄ Then, the particle size of the composite ceramic is not changed greatly, and the uniformity is improved slightly; 30% of Si ₃ N ₄ The ceramic particles of (a) become significantly uniform in shape and fine in size; when the amount added is 40% ₃ N ₄ When the ceramic material is used, the particles of the ceramic material are finest and the uniformity is best; adding 50% of Si ₃ N ₄ In the case of finer particles, coarse particles of individual sizes appear, which affects the overall homogeneity of the material. The results show that with Si ₃ N ₄ The more the addition amount is increased, the more compact the structure of the composite ceramic becomes and the better the uniformity of the material becomes. Si ₃ N ₄ The CPP crystal grain refining function can be achieved. (5) Si ₃ N ₄ Tris solution degradation research of/CPP composite ceramic material

1) Change in weight loss

For the prepared compact composite bioceramic, the degradation rate is calculated by the weight loss of the compact composite bioceramic soaked in a Tris buffer solution. FIG. 10 shows Si in various proportions ₃ N ₄ Weight loss during the soaking process of the CPP composite ceramic. As can be seen, si is added ₃ N ₄ The weight change trend of the post composite material is basically consistent, the weight change in the early stage of soaking is severe, and the weight loss degree is gradual when 21 days are reached. With Si ₃ N ₄ The content is increased, the weight loss of the composite ceramic is increased, the degradation rate is increased, the degradation weight loss rate after soaking for 28 days is 0.5665% -0.9588%, and compared with the weight loss amount (0.157%) of pure CPP, the degradation rate is improved. 10% of Si ₃ N ₄ And 20% of Si ₃ N ₄ The composite ceramic sample of (1) showed weight increase before 7 days of immersion and weight began to decrease after 7 days, indicating that Si was present ₃ N ₄ When the content is low, the degradation rate is low and then high in the composite material soaking process, and the deposition rate of the calcium-phosphorus compound is high and then low; to 30% of Si ₃ N ₄ 、40％Si ₃ N ₄ And 50% of Si ₃ N ₄ All show weight loss during the soaking process, sayMing Si ₃ N ₄ The balance of dissolution and precipitation of calcium and phosphorus ions in the CPP can be changed, so that the degradation rate is greater than the deposition rate, the degradation process of the CPP ceramic is accelerated, and the degradation performance is improved.

2) Change in pH

As can be seen from FIG. 11, si ₃ N ₄ In the process of soaking the/CPP composite ceramic in a Tris solution, the curve fluctuation is frequent, but the curve fluctuation is still kept within the range of 7.45 +/-0.05, and after soaking for 24 days, the pH value begins to be stabilized at about 7.45, thereby meeting the safety standard of the human body alkalescent pH condition. The composite ceramics of different proportions have different degrees of pH fluctuation, wherein, 10% of Si ₃ N ₄ The pH change amplitude of the soaking solution is the minimum, which shows that the stability in the soaking process is better; 40% of Si ₃ N ₄ The maximum range of pH change indicates frequent ion exchange and relatively poor stability, while the degradation performance may be improved by active ion exchange.

3) Infrared spectroscopic analysis

FIG. 12 is Si at different ratios ₃ N ₄ The infrared spectrum of the/CPP composite ceramic degraded in Tris solution. As can be seen from the curves (b) (C) (d) (e) (f), the stretching vibration peaks of O-H and C-O structures can be still detected after the composite ceramic is degraded, and the peak length is 1633cm ^-1 The shear vibration peak of N-H appears nearby, and is 613cm ^-1 A peak of the P-O functional group appears in the vicinity. In infrared contrast to the unsqueked composite ceramic represented by curve (a), si ₃ N ₄ Is added to the mixture at 680-790 cm ^-1 The peak strength of the P-O-P structure in the range becomes weaker and shows a positive correlation tendency, indicating that Si is present ₃ N ₄ The degradation rate of the/CPP composite ceramic is greater than that of the pure CPP ceramic.

4) Micro-morphology

A, B, C, D, E in FIG. 13 represent the addition of 10% Si, respectively ₃ N ₄ 、20％Si ₃ N ₄ 、30％Si ₃ N ₄ 、40％Si ₃ N ₄ And 50% of Si ₃ N ₄ The surface appearance of the composite ceramic sample after being soaked in Tris buffer solution for 28 days. The surface of the soaked material is covered by a layer of spherical particles with smaller sizeDeposit layer with Si ₃ N ₄ Increased content, found that the amount of small particle deposition exhibits a profile of increasing followed by decreasing, 40% Si ₃ N ₄ The deposition layer on the surface of the composite ceramic is the largest, and the particles are relatively uniform. (6) Si ₃ N ₄ SBF solution degradation research of/CPP composite ceramic

1) Change in weight loss

Different proportions of Si ₃ N ₄ The weight change of the/CPP composite ceramic degraded in the SBF solution is shown in figure 14, and in the process of soaking for 28 days, the weight loss of the pure CPP ceramic is very small and is only 0.168%, and the degradation rate is slow; si in composite ceramic ₃ N ₄ Increased content, increasing the weight loss after soaking in SBF, 10% Si ₃ N ₄ The degradation weight loss of the composite ceramic of (a) is 0.5665%, while 50% Si ₃ N ₄ The weight loss of the composite ceramic is 1.7733 percent which is about 11 times of that of pure CPP, which shows that the composite ceramic has better degradation performance.

2) Change in pH

Different proportions of Si ₃ N ₄ The pH change of the/CPP composite ceramic degraded in the SBF solution is shown in FIG. 15.

As can be seen, si ₃ N ₄ The pH change conditions of the/CPP composite ceramic are basically consistent, the overall pH shows a reduction trend, and the pH is quickly reduced in the early stage of degradation and then gradually stabilized to about 7.1. The degradation process is smaller than the pH value (7.45) of a Tris solution, which proves that the composite ceramic in the SBF solution is degraded more quickly, the ion exchange in the solution is favorable for promoting the degradation transformation of the ceramic material, and Si is presumed to be in the corresponding biological environment ₃ N ₄ the/CPP composite ceramic degrades more quickly.

3) Infrared spectroscopic analysis

FIG. 16 is Si at different ratios ₃ N ₄ Infrared spectrum of the/CPP composite ceramic degraded in SBF solution. As can be seen from the graph, the degradation of the composite ceramic can be detected at 3190cm ^-1 And 1632cm ^-1 The expansion and bending vibration peak of an O-H structure appears nearby, and is 1552cm ^-1 The peak of C-O structure appears at 1633cm ^-1 The shear shock peak of N-H appears nearby and is 613cm ^-1 And 1022cm ^-1 A peak of P-O functional group appears in the vicinity. Si ₃ N ₄ Is added to the mixture at 680-790 cm ^-1 The peak strength of the P-O-P structure in the range is weakened and shows a positive correlation trend, and compared with the un-soaked composite ceramic shown in the curve (a), the peak strength of the P-O-P long chain structure of the composite ceramic is gradually weakened, which shows that Si is contained in the composite ceramic ₃ N ₄ Can promote the degradation of the ceramic material, thereby illustrating that Si ₃ N ₄ The degradation rate of the/CPP composite ceramic is greater than that of the pure CPP ceramic.

4) Phase analysis

Si at different scales from FIG. 17 ₃ N ₄ The phase of the/CPP composite ceramic after being degraded for 28 days in SBF shows that compared with the pure CPP ceramic material represented by the curve (a), the composition of the surface phase of the composite ceramic after being soaked is obviously changed, the peak intensities of the original phase beta-CPP at the positions of 19.34 degrees, 20.81 degrees, 23.11 degrees, 25.25 degrees, 27.6 degrees and 35.31 degrees are reduced, and the decomposition product Ca is reduced ₄ P ₆ O ₁₉ Decrease in peak of (C), appearance of more Ca ₂ P ₂ O ₇ The diffraction peak shows that the CPP is decomposed more thoroughly, and the decomposition products are more abundant; compared with the degraded phases of pure CPP ceramics, additional diffraction peaks of HA appear at 18.72 °,35.27 °,40.17 ° and 46.52 °, indicating that the composite ceramic sample is degraded in SBF to generate more hydroxyapatite and calcium phosphorus compounds, and the transformation of the compounds can be accelerated to deposit on the surface of the material.

5) Micro-morphology

Different ratios of Si from FIG. 18 ₃ N ₄ The microcosmic appearance of the/CPP composite ceramic degraded in the SBF solution shows that more gaps and holes are formed on the surface of the material, the amount of deposited particles is obviously improved, compared with the surface appearance of the Tris solution after degradation, spherical particles are more widely distributed, the size of the particles is larger, the degradation degree is higher, and more apatite and calcium-phosphorus compounds are generated by degradation. Fig. A2 and B2 show cracks, which may be caused when the test specimen is dried.

6) Compressive strength

Different proportions of Si ₃ N ₄ Compressive strength change of/CPP composite ceramic degraded in SBF solutionAs shown in fig. 19. The graph shows the compressive strengths of the ceramic samples before immersion, after 21 days of immersion and after 28 days of immersion, and it can be seen that the content of Si is 10% ₃ N ₄ The highest compressive strength after soaking for 28 days is 7.31MPa, which is 39 percent of the original compressive strength; 20% of Si ₃ N ₄ The compressive strength after 28 days became 5.57MPa, which was 26% of the original one; 30% of Si ₃ N ₄ The compressive strength after 28 days became 4.22MPa, which was 17% of the original; 50% of Si ₃ N ₄ The lowest compressive strength after soaking is 3.16MPa, which is about 14 percent of the original compressive strength. The compressive strength of the composite ceramic is obviously reduced after 21 days and 28 days of soaking, and the compressive strength is reduced along with Si ₃ N ₄ The content is increased, and the strength after soaking is gradually reduced, which is different from the strength rule before soaking. The reason for this may be that the structure of the composite material becomes loose due to degradation, and Si in the material becomes loose ₃ N ₄ Is corroded by SBF solution, so that a gap is formed at the joint of two substances in the composite material, the binding force is reduced, and Si before the material is soaked ₃ N ₄ The effect of the reinforcing phase is reduced, the strength is reduced, and the phenomenon follows Si ₃ N ₄ The increase in the content is aggravated.

3. Porous Si ₃ N ₄ Performance analysis of/CPP composite ceramic Material

(1) Compressive strength

FIG. 20 is a graph of porous Si obtained by mixing powders of different proportions with stearic acid of two particle sizes (50-80 mesh and 80-120 mesh) added ₃ N ₄ Compressive strength of the/CPP composite ceramic sample. It can be seen that when the volume percentage of the pore-forming agent is 30%, the particle size of the stearic acid pore-forming agent is inversely proportional to the compressive strength, and the particle size is large and the corresponding compressive strength is small. The compression strength of the pure CPP ceramic with 30 percent of volume ratio is 4.96MPa (50 to 80 meshes) and 5.22MPa (80 to 120 meshes), when Si is used ₃ N ₄ When the content is 10%, the compression strength of the composite material is lower than that of pure CPP ceramic, and the strength of stearic acid under 50-80 meshes and 80-120 meshes is 4.38MPa (50-80 meshes) and 4.53MPa (80-120 meshes) respectively; when Si is present ₃ N ₄ At contents above 20%, the strength begins to be higher than that of pure CPP, when Si is present ₃ N ₄ At a content of 40%, compressive strengthThe highest pressure reaches 8.76MPa (50-80 meshes) and 9.57MPa (80-120 meshes); when Si is present ₃ N ₄ When the content is 50%, the compressive strength is reduced, and the compressive strength is respectively 6.38MPa (50-80 meshes) and 7.33 MPa (80-120 meshes).

(2) Micro-morphology

FIG. 21 shows porous 40% Si ₃ N ₄ The microstructure of the/CPP composite ceramic is shown in the figure A, wherein the surface morphology of the pore-foaming agent added in 30% by volume is shown in the figure B, and the surface morphology of the pore-foaming agent added in 50% by volume is shown in the figure B. The structure facilitates the communication among all the holes in the porous material to form an open pore channel, which is favorable for the cell adhesion and the material transmission after the material is implanted, thereby ensuring the smooth growth of bone tissues.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Si ₃ N ₄ The preparation method of the/CPP composite ceramic material is characterized by comprising the following steps: first preparing CPP suspension and Si ₃ N ₄ Suspension of Si ₃ N ₄ Adding the suspension into the CPP suspension, stirring uniformly, filtering, pressing and sintering to obtain Si ₃ N ₄ a/CPP composite ceramic material;

pouring the pre-sintered material into a mortar for coarse grinding, then adding alcohol and ball-milling by using a ball mill to obtain CPP powder, and pouring the CPP powder into deionized water to be stirred to form CPP suspension; the conditions of the solid-phase sintering method are as follows: heating from room temperature to 500-600 ℃ at the heating rate of 4 ℃/min, and preserving heat for 10-15h; under the heating temperature and the heat preservation time, gamma + beta type calcium polyphosphate can be obtained, and only gamma type calcium polyphosphate can be obtained when the heating temperature is lower than the heating temperature or the heat preservation time is shorter than the heat preservation time;

Si ₃ N ₄ is added in an amount of Si ₃ N ₄ The mass of the/CPP composite material is 10-50%.

2. The method of claim 1, wherein: and removing powder on the part of the sintered material in contact with the bottom of the porcelain boat, and selecting a middle part of the sintered material to pour into a mortar for coarse grinding.

3. The method of claim 1, wherein: the ball milling time is 1-2h.

4. The method of claim 1, wherein: and (4) drying after ball milling, and sieving by a 200-mesh sample sieve to obtain screened CPP powder.

5. The method of claim 1, wherein: said Si ₃ N ₄ The preparation method of the suspension comprises the following steps: mixing Si ₃ N ₄ Dissolving the powder in a dispersant, and stirring uniformly to obtain Si ₃ N ₄ And (3) suspension.

6. The method of claim 5, wherein: said Si ₃ N ₄ The powder is 500-600nm superfine powder; the dispersant is polyethylene glycol.

7. The method of claim 6, wherein: the molecular weight of the polyethylene glycol is 4000.

8. The method of claim 5, wherein: the addition amount of the dispersant is Si ₃ N ₄ 0.4-0.6% of the powder.

9. The method of claim 5, wherein: the pH was adjusted to between 9 and 10 during stirring.

10. The method of claim 5, wherein: and sodium hydroxide is adopted for pH adjustment in the stirring process.

11. The method of claim 5, wherein: and after stirring uniformly, carrying out ultrasonic treatment for 30-40 min.

12. The method of claim 1, wherein: si ₃ N ₄ Is added in an amount of Si ₃ N ₄ The mass of the/CPP composite material is 25-45%.

13. The method of claim 1, wherein: si ₃ N ₄ Is added in an amount of Si ₃ N ₄ 35-45% of the mass of the/CPP composite material.

14. The method of claim 1, wherein: si ₃ N ₄ Is added in an amount of Si ₃ N ₄ 40% of the mass of the/CPP composite material.

15. The method of claim 1, wherein: si ₃ N ₄ Slowly adding the suspension into the CPP suspension for multiple times, stirring while adding, keeping stirring for 30-40min, then carrying out centrifugal treatment, carrying out washing, drying and 200-mesh sieve sieving to obtain composite powder, and then mixing the composite powder with the adhesive according to the proportion of 5g: (0.5-2) mL of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder; the dry pressing forming process is completed, and Si is obtained after sintering in a resistance furnace ₃ N ₄ a/CPP composite ceramic material; wherein, the sintering process is that according to the heating rate of 4 ℃/min, the temperature is firstly heated to 400 ℃ from the room temperature, the heat is preserved for 2h, then the temperature is heated to 850 ℃, the heat is preserved for 1.5h, and the temperature is cooled to the room temperature along with the furnace.

16. The method of claim 15, wherein: the ratio of powder to binder was 5g:1mL, and adding 5% by mass of polyvinyl alcohol aqueous solution as a binder.

17. Si obtained by the production method according to claim 1 ₃ N ₄ the/CPP composite ceramic material.

18. Porous Si ₃ N ₄ The preparation method of the CPP composite ceramic material is characterized by comprising the following steps: any Si according to claims 1-17 ₃ N ₄ The preparation method of the CPP composite ceramic material comprises the following steps of further processing CPP powder to obtain a porous CPP material, and then carrying out subsequent steps, wherein the preparation method of the porous CPP material comprises the following steps:

mixing Si ₃ N ₄ Mixing the/CPP composite powder with a stearic acid pore-foaming agent according to a proportion, wherein the proportion of the stearic acid pore-foaming agent is 10-50Vol%; then, uniformly mixing for 20min by using a vortex mixer, and then mixing according to the ratio of powder to the binder of 5g: (0.5-2) mL of polyvinyl alcohol aqueous solution with the mass fraction of 5% is added as a binder; after being uniformly mixed, the powder is put into a die for dry pressing and forming, and the obtained blank is put into a resistance furnace for sintering to obtain Si ₃ N ₄ a/CPP composite ceramic material; the sintering process comprises the steps of heating from room temperature to 400 ℃ according to the heating rate of 4 ℃/min, preserving heat for 2h, heating to 850 ℃, preserving heat for 1.5h, and cooling to room temperature along with a furnace.

19. The method of claim 18, wherein: the proportion of the stearic acid pore-forming agent is 15-45Vol%.

20. The method of claim 18, wherein: the proportion of the stearic acid pore-forming agent is 25-35Vol%.

21. The method of claim 18, wherein: the proportion of stearic acid porogen was 30Vol%.

22. The method of claim 18, wherein: the stearic acid pore-foaming agent has the particle size of 50-80 meshes and 80-120 meshes.

23. The method of claim 18, wherein: the ratio of powder to binder was 5g:1mL, and adding 5% by mass of polyvinyl alcohol aqueous solution as a binder.

24. The method of claim 18, wherein: and pressing and molding on a hydraulic machine according to the method of 1MPa of pressure and 1min of pressure maintaining.

25. The method of claim 18, wherein: the sintering speed is 4 ℃/min, the material is firstly heated to 400 ℃ from the room temperature, the temperature is preserved for 2h, then the temperature is raised to 850 ℃, the temperature is preserved for 1.5h, and the material is cooled to the room temperature along with the furnace, thereby completing the final sintering process of the material.

26. Porous Si obtained by the production method according to claim 18 ₃ N ₄ the/CPP composite ceramic material.

27. Si according to claim 17 ₃ N ₄ The application of the/CPP composite ceramic material as a degradable implant material.

28. Si according to claim 17 ₃ N ₄ The application of the/CPP composite ceramic material as a degradable implant material in the repair of artificial bone defects.

29. Porous Si according to claim 26 ₃ N ₄ The application of the/CPP composite ceramic material as a degradable implant material.

30. Porous Si according to claim 26 ₃ N ₄ /CPP composite ceramic materialThe degradable implant material can be used for repairing artificial bone defects.