Porous biological ceramic as well as preparation method and application thereof

Abstract

The invention provides porous biological ceramic as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing aluminum oxide slurry with a pore forming agent to obtain mixed slurry; carrying out light curing reaction on the mixed slurry in a layer-by-layer projection manner by adopting DLP 3D printing, and carrying out layer-by-layer printing, accumulation and forming to obtain a ceramic body; according to the preparation method, through the aluminum oxide slurry composite pore-forming agent and the DLP 3D printing technology, it is guaranteed that no through hole exists in the material, high density and mechanical strength are maintained, and the problem that in the prior art, surface performance and mechanical performance are difficult to consider at the same time is solved; a discrete porous structure is constructed on the surface of the high-solid-content aluminum oxide ceramic, so that accurate regulation and control of the surface roughness are realized, surface discrete holes are directly formed, and a complex post-treatment process is omitted; through the sintering process, the overall sintering shrinkage rate is controlled, the forming precision of a complex structure is improved, the large-scale production requirement is met, and the material can be applied to bone tissue engineering scaffolds and tooth restoration materials.

Description

Technical Field

[0001] The present application relates to the technical field of bioceramic materials, and in particular to a porous bioceramic, a preparation method and applications thereof. Background Art

[0002] Orthopedic implants, such as femoral prostheses, require a rough surface to promote bone cell adhesion while also possessing high strength (≥150 MPa) to withstand loads. Traditionally, acid etching increases roughness but introduces microcracks, resulting in a decrease in strength.

[0003] CN118047626A uses 3D printing laser sintering technology to prepare alumina ceramics with high porosity and high strength. However, due to the high pore connectivity, the density of porous ceramics is often less than 85%, and the strength is only 35-95MPa, making them unsuitable for load-bearing scenarios.

[0004] CN112441842A provides an efficient and controllable method for preparing porous bioceramic coatings. The porous coating is prepared by uniformly dispersing a pore-forming agent. However, the substrate needs to be subjected to surface pretreatment such as ultrasonic cleaning, sandblasting, and organic solvent immersion. The process is complex and the material shrinkage rate is 15%-20%, affecting the accuracy.

[0005] CN103641510A proposes a method for preparing O-Sialon porous ceramics by adding a polymethacrylate pore-forming agent. Through spray granulation and in-situ reaction sintering, the material achieves a combination of high porosity and good mechanical properties. However, conventional powder bed fusion processes rely on laser sintering, resulting in low room temperature flexural strengths of 50-120 MPa and poor controllability of surface roughness.

[0006] The porous bioceramics currently provided by existing technologies have insufficient strength due to their through-pore structure and can only be used in non-load-bearing scenarios; they are highly process-dependent and require post-processing to optimize the surface, which is complex and costly; and conventional pore-forming processes volatilize a large amount of pore-forming agent during sintering, resulting in a high overall shrinkage rate of the material, affecting the molding accuracy of complex structures. Summary of the Invention

[0007] In view of this, it is necessary to provide a porous bioceramic, a preparation method and its application that ensures the formation of surface pore structure while maintaining the density of the cross section and the mechanical properties of the material to address the defects of the existing technology.

[0008] To solve the above problems, this application adopts the following technical solutions:

[0009] One of the purposes of this application is to provide a method for preparing a porous bioceramic, comprising the following steps:

[0010] mixing alumina slurry with a pore-forming agent to obtain a mixed slurry;

[0011] Using digital light processing technology in a layer-by-layer projection manner, the mixed slurry undergoes a light-curing reaction, and is printed and formed layer by layer to obtain a ceramic body;

[0012] The ceramic body is subjected to high temperature treatment to obtain the porous bioceramic.

[0013] In some embodiments, the step of mixing the alumina slurry with the pore-forming agent to obtain the mixed slurry specifically includes the following step: dispersing the pore-forming agent in the alumina slurry by stirring or ultrasonic dispersion.

[0014] In some embodiments, the solid content of the alumina slurry is 80%, and the particle size of α-Al2O3 is 1-5 μm.

[0015] In some embodiments, the mass ratio of the pore-forming agent to the alumina slurry is 2:98 or 3:97, the pore-forming agent is a mixture of polymethyl methacrylate and polylactic acid, and the mass ratio of the polymethyl methacrylate to the polylactic acid is 1:3.

[0016] In some embodiments, the particle size of the polymethyl methacrylate is 3-5 μm, and the particle size of the polylactic acid is 5-15 μm.

[0017] In some embodiments, the pore-forming agent is an organic polymer material or a soluble salt. The organic polymer material includes polyvinyl alcohol or polyethylene glycol, and the soluble salt includes sodium chloride or ammonium chloride.

[0018] In some of the embodiments, the step of using digital light processing technology to project layer by layer to cause the mixed slurry to undergo a photocuring reaction, and printing and accumulating the slurry layer by layer to obtain a ceramic body specifically includes the following steps: placing the mixed slurry in a material tank of a DLP photocuring 3D printer, and projecting a pre-designed model layer by layer through a computer-controlled digital light processing system to cause the slurry to undergo a photocuring reaction in a specific area, and printing and accumulating the slurry layer by layer to obtain a ceramic body.

[0019] In some of the embodiments, in the above-mentioned molding process, a dual-channel LED light source is used, whose wavelength is 405nm, and the printing parameters include: the light intensity is set to 60%, the layer thickness is 10μm, the base exposure time is 2000ms, the common layer exposure time is 1000ms, and the scraping speed is 60mm / s.

[0020] In some embodiments, the step of subjecting the ceramic body to high temperature treatment to obtain the porous bioceramic specifically includes the following steps:

[0021] The ceramic body is dried at 30-80°C for 12-24 hours, and then the dried ceramic body is sintered. The sintering specifically includes: heating from room temperature to 500°C at a rate of 5°C / min, keeping warm for 1 hour; then heating to 600°C at a rate of 10°C / min, keeping warm for 2 hours; finally, heating to 1400-1600°C at a rate of 10-15°C / min, keeping warm for 2-3 hours, and finally naturally cooling to obtain the porous bioceramic.

[0022] In some embodiments, the surface of the porous bioceramic has a pore structure of 2-30 μm and a surface roughness Ra within the range of 0.8-20.

[0023] The second purpose of the present application is to provide a porous bioceramic prepared by any of the preparation methods described above.

[0024] The third purpose of this application is to provide an application of the porous bioceramic in bone tissue engineering scaffolds and tooth repair materials.

[0025] This application adopts the above technical solution, and its beneficial effects are as follows:

[0026] The porous bioceramic, preparation method, and application provided by the present application include mixing an alumina slurry with a pore-forming agent to obtain a mixed slurry; using digital light processing technology to project layer by layer, causing the mixed slurry to undergo a photocuring reaction, and printing and accumulating layer by layer to obtain a ceramic body; and subjecting the ceramic body to high-temperature treatment to obtain the porous bioceramic. The present application ensures that there are no through holes in the material, maintains high density (>90%) and mechanical strength (flexural strength ≥180 MPa), and solves the problem of the difficulty in balancing surface properties and mechanical properties in the prior art by designing a formula of alumina slurry composite pore-forming agent and optimizing the printing process using digital light processing technology. In addition, a discrete porous structure is constructed on the surface of the high-solid content alumina ceramic, achieving precise control of the surface roughness Ra 0.5-100 μm and the pore diameter 2-50 μm, directly forming discrete surface pores and omitting the complex post-processing process. Through the sintering process, the overall sintering shrinkage rate is controlled to be less than 10%, improving the molding accuracy of the complex structure, meeting the needs of large-scale production, and can be applied to bone tissue engineering scaffolds and tooth restoration materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1A flowchart of the steps of the method for producing porous bioceramics provided in an embodiment of the present application.

[0029] Figure 2 This is a scanning electron micrograph of the alumina ceramic sample prepared in Comparative Example 1 of the present application.

[0030] Figure 3 This is a scanning electron micrograph of the alumina ceramic sample prepared in Example 1 of the present application.

[0031] Figure 4 This is a measurement diagram of the sample surface roughness provided in Example 1 of this application.

[0032] Figure 5 This is a scanning electron micrograph of the cross-section of the alumina ceramic sample provided in Example 2 of the present application.

[0033] Figure 6 This is a microscopic diagram of the sample surface provided in Example 2 of this application.

[0034] Figure 7 This is a measurement diagram of the sample surface roughness provided in Example 2 of this application. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0038] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] See also Figure 1 , is a flow chart of the steps of the method for preparing the porous bioceramic provided in an embodiment of the present application, which includes the following steps S110 to S130. The implementation method of each step is described in detail below.

[0040] Step S110: mixing alumina slurry and a pore-forming agent to obtain a mixed slurry.

[0041] In this embodiment, the step of mixing the alumina slurry and the pore-forming agent to obtain the mixed slurry specifically includes the following steps: dispersing the pore-forming agent in the alumina slurry by stirring or ultrasonic dispersion.

[0042] In this embodiment, the alumina slurry adopts a basic slurry with a high solid content, for example, a solid content of 80% and an α-Al 2 O 3 particle size of 1-5 μm.

[0043] It can be understood that this embodiment uses commercially available alumina slurry with a high solid content of 80% as the basic material. Due to the high solid content, the alumina particles in the slurry are densely packed, and the internal structure is relatively stable during the subsequent molding and processing process, providing the basic conditions for avoiding the formation of holes in the cross section.

[0044] In this embodiment, the pore-forming agent is a mixture of polymethyl methacrylate (PMMA) and polylactic acid (PLA).

[0045] It can be understood that the present embodiment uses a mixture of PMMA and PLA as the composite pore-forming agent, which has a suitable volatilization or decomposition temperature and rate and is well dispersed in the slurry.

[0046] Furthermore, the mass ratio of PMMA to PLA is 1:3, the mass ratio of pore-forming agent to alumina slurry is 2:98 or 3:97, the particle size of PMMA microspheres is 3-5 μm, and the particle size of PLA micropowder is 5-15 μm, so as to provide precise pore-forming cores.

[0047] It should be noted that: PMMA / PLA is selected as the pore-forming agent in this embodiment, and two specific addition ratios and particle sizes are precisely set, that is, the mass ratio of PMMA / PLA to alumina slurry is 97:3 or 98:2, respectively, and the mass ratio of PMMA to PLA is 1:3, the PMMA particle size is 3 μm, and the PLA particle size is 5-15 μm. By setting the above ratio range, the surface roughness and pore structure of the ceramic sample can be effectively regulated; at the same time, the pore-forming agent is uniformly dispersed in the high solid content (80%) alumina slurry through efficient stirring, ultrasonic dispersion, etc., to ensure the consistency of the performance of each part during the printing process and the uniformity of the pore structure on the surface of the subsequent ceramic product.

[0048] Furthermore, the pore-forming agent provided in this embodiment can also be replaced by other organic polymer materials, such as polyvinyl alcohol (PVA) and polyethylene glycol (PEG). These materials have different thermal decomposition temperatures and volatility characteristics. By adjusting their ratio with the alumina slurry and the dispersion method in the slurry, surface pore structures of different sizes and distributions can be formed, achieving another effect of regulating the surface roughness of the ceramic. In addition, soluble salts such as sodium chloride and ammonium chloride can also be considered as pore-forming agents. They can be evenly dispersed in the alumina slurry and then dissolved to remove the pore-forming agent to form pores after forming, providing a new way to regulate surface structure.

[0049] Step S120: using digital light processing technology to project layer by layer, causing the mixed slurry to undergo a photocuring reaction, and printing and accumulating layer by layer to obtain a ceramic body.

[0050] In this embodiment, the molding process utilizes digital light processing (DLP) 3D printing technology. Based on the principle of photocuring, this technology uses a digital micromirror device to project a cross-sectional image of the product onto the surface of liquid bright resin, which is then photocured layer by layer. Because each layer is cured in a slide-like manner, DLP 3D printing is faster than the comparable SLA method.

[0051] In this embodiment, the step of using digital light processing technology to project layer by layer to cause the mixed slurry to undergo a photocuring reaction, and printing and accumulating the slurry layer by layer to obtain a ceramic body specifically includes the following steps: placing the mixed slurry in a material tank of a DLP photocuring 3D printer, and projecting a pre-designed model layer by layer through a computer-controlled digital light processing system to cause the slurry to undergo a photocuring reaction in a specific area, and printing and accumulating the slurry layer by layer to obtain a ceramic body.

[0052] Furthermore, in the above-mentioned molding process, a dual-channel LED light source with a wavelength of 405nm was used, and the printing parameters were as follows: the light intensity was set to 60%, the layer thickness was 10μm, the base exposure time was 2000ms, the common layer exposure time was 1000ms, and the scraping speed was 60mm / s. Through the above parameters, the alumina / PMMA / PLA ceramic body was obtained by printing and accumulating layer by layer.

[0053] It should be noted that in this embodiment, DLP 3D printing technology is used to precisely set printing parameters such as light source intensity, exposure time, and layer thickness during the molding process. Through the coordinated adjustment of these parameters, the pore-forming agent in the surface layer slurry is more likely to volatilize or decompose to form holes during photocuring and subsequent processing. At the same time, the internal curing environment is closed to limit the escape of the pore-forming agent, thereby achieving a differentiated structure with pores on the surface and no holes in the cross section.

[0054] In addition, this embodiment utilizes the difference between the surface and internal curing environments during the DLP 3D printing process, combined with the characteristics of high-solid content slurry, to successfully form holes on the surface of the ceramic sample while maintaining a dense cross-section. While giving the ceramic specific surface properties, it effectively guarantees the mechanical properties of the material, breaking through the bottleneck of the existing technology that is difficult to balance surface treatment and mechanical properties.

[0055] In addition, this embodiment uses DLP 3D printing technology combined with high-solid content slurry. DLP 3D printing is a digital molding technology. Compared with complex and environmentally unfriendly existing processes such as chemical etching, it does not require the use of large amounts of chemical reagents and has the characteristics of high molding precision and high efficiency.

[0056] Step S130: performing high-temperature treatment on the ceramic body to obtain the porous bioceramic.

[0057] In this embodiment, the step of subjecting the ceramic body to high temperature treatment to obtain the porous bioceramic specifically includes the following steps:

[0058] The ceramic body is dried at 30-80°C for 12-24 hours, and then the dried ceramic body is sintered. The sintering specifically includes: heating from room temperature to 500°C at a rate of 5°C / min, keeping warm for 1 hour; then heating to 600°C at a rate of 10°C / min, keeping warm for 2 hours; finally, heating to 1400-1600°C at a rate of 10-15°C / min, keeping warm for 2-3 hours, and finally naturally cooling to obtain the porous bioceramic.

[0059] It should be noted that this embodiment adopts a rapid heating method in the post-molding processing stage. Since the high-solid content slurry itself has a low shrinkage potential, the rapid heating treatment further optimizes the shrinkage control. During the rapid heating process, the temperature rises rapidly, allowing the pore-forming agent to volatilize or decompose in a relatively short period of time, forming a surface pore structure. At the same time, due to the rapid heating rate, the material does not have time to generate large stresses and defects, effectively controlling the sample shrinkage rate to less than 10%. In addition, during the rapid heating process, the interaction between the internal particles and the dense stacking structure brought about by the high solid content limit the formation of pores by the pore-forming agent at the cross section, ensuring the density and mechanical properties of the ceramic sample cross section.

[0060] In addition, during the above-mentioned high-temperature treatment process, it can also be combined with atmosphere protection treatment, and the temperature treatment can be carried out in an inert gas (such as argon) or reducing gas (such as hydrogen) atmosphere to change the chemical properties of the material surface, further regulate the surface properties, mechanical properties and control the shrinkage rate of the material.

[0061] The preparation method of the porous bioceramic provided in this application, through the above-mentioned raw materials, molding process and high-temperature process, the above complete and synergistic technical solution ultimately achieves a porous bioceramic surface with discrete pores of 2-30 μm, a spacing of 10-200 μm, and no connectivity; a porosity of 15%-30%, a surface roughness Ra of 0.8-20 μm, a density greater than 90%, a flexural strength of 250-320 MPa, and no through holes.

[0062] The preparation method of porous bioceramics provided in this application ensures that there are no through holes inside the material, maintains high density (>90%) and mechanical strength (flexural strength ≥180MPa), and solves the problem of difficult balance between surface performance and mechanical properties in the existing technology through the formulation design of alumina slurry composite pore-forming agent, digital light processing technology printing process optimization and rapid heating process; and constructs a discrete porous structure on the surface of high-solid content alumina ceramics to achieve precise control of surface roughness Ra 0.5-100μm and pore size 2-50μm, directly forming discrete holes on the surface and omitting complex post-processing process; through the sintering process, the overall sintering shrinkage rate is controlled to be less than 10%, thereby improving the molding accuracy of complex structures and meeting the needs of large-scale production.

[0063] The porous bioceramics prepared in this application have a controllable surface roughness and a specific pore structure, and can be used as bone tissue engineering scaffolds. The surface pore structure is conducive to cell adhesion, growth, and proliferation, while the appropriate roughness can promote cell differentiation and tissue ingrowth, providing a good support environment for bone tissue repair and regeneration. In addition, they can also be used to prepare dental restoration materials. The surface roughness can affect the bonding strength between the material and the surrounding tissue, while the pore structure helps to improve the material's biocompatibility and drug loading capacity, achieve slow drug release, and assist in the treatment of periodontal diseases.

[0064] The following is a detailed description of the above technical solutions of this application in conjunction with specific embodiments.

[0065] Comparative Example 1:

[0066] (1) Prepare alumina ceramic slurry with a solid content of 80% and an α-Al2O3 particle size of 1-5 μm.

[0067] (2) Printing: Use 3D modeling software to draw a printable model, then import the 3D model into a computer control system to generate G-code. Use a down-sink DLP device, a dual-channel LED light source with a wavelength of 405nm, a light intensity setting of 60%, a layer thickness of 10μm, a base exposure time of 2000ms, a normal layer exposure time of 1000ms, and a scraping speed of 60mm / s. Print layer by layer and accumulate to obtain an alumina / PMMA / PLA ceramic body. CAD, UG, Solidworks, and other software can be used for modeling.

[0068] (3) Drying and sintering of the green body: The green body obtained in step (2) is dried in a drying oven at 30-80°C for 12-24 hours, and then the dried green body is placed in a muffle furnace for sintering. Specifically, the temperature is raised from room temperature to 500°C at a rate of 5°C / min and kept at this temperature for 1 hour; then the temperature is raised to 600°C at a rate of 10°C / min and kept at this temperature for 2 hours to fully remove the pore-forming agent; finally, the temperature is raised to 1400-1600°C at a rate of 10-15°C / min and kept at this temperature for 2-3 hours, and finally, the sample is obtained by natural cooling.

[0069] (4) The product obtained by sintering in Comparative Example 1 has no obvious holes on its surface, a room temperature flexural strength between 300-320 MPa, an XY direction shrinkage of 18%, a Z direction shrinkage of 22%, and a uniform microstructure.

[0070] See also Figure 2 , is a scanning electron micrograph of the alumina ceramic sample prepared in Example 1, wherein the magnification is 500 times.

[0071] Example 1:

[0072] (1) Add PMMA microspheres and PLA powder to alumina ceramic slurry and stir in a sealed container for 10 h to mix evenly. The mass ratio of alumina ceramic slurry to PMMA / PLA is 98:2, the mass ratio of PMMA to PLA is 1:3, the solid content of alumina ceramic slurry is 80%, the particle size of α-Al2O3 is 1 μm, the particle size of PMMA microspheres is 3 μm, and the particle size of PLA powder is 5 μm. The stirring speed is 300 r / min.

[0073] (2) Printing: Use 3D modeling software to draw a printable model, then import the 3D model into the computer control system to generate G-code. Use a sinking DLP device, a dual-channel LED light source with a wavelength of 405nm, a light intensity setting of 60%, a layer thickness of 10μm, a base exposure time of 2000ms, a normal layer exposure time of 1000ms, and a scraping speed of 60mm / s. Print layer by layer and accumulate to obtain an alumina / PMMA / PLA ceramic body. CAD, UG, Solidworks, and other software can be used for modeling.

[0074] (3) Drying and sintering of the green body: The green body obtained in step (2) was dried in a drying oven at 30°C for 12 hours, and then the dried green body was placed in a muffle furnace for sintering. Specifically, the temperature was raised from room temperature to 500°C at a rate of 5°C / min and kept at this temperature for 1 hour; then the temperature was raised to 600°C at a rate of 10°C / min and kept at this temperature for 2 hours to fully remove the pore-forming agent; finally, the temperature was raised to 1400°C at a rate of 10°C / min and kept at this temperature for 2 hours, and finally, the sample was naturally cooled to obtain.

[0075] (4) The surface pores of the product obtained by sintering the embodiment 1 are 2 μm, discrete, and non-connected. The room temperature flexural strength is 290 MPa, the shrinkage in the XY direction is 8%, and the shrinkage in the Z direction is 11%. Figure 3 The Ra of area 1 shown is 0.886, and the microstructure is uniform.

[0076] Figure 3 This is a scanning electron micrograph of the alumina ceramic sample prepared in Example 1, with a magnification of 500 times. Figure 4 This is the surface roughness measurement diagram of the sample in Example 1.

[0077] Example 2:

[0078] (1) PMMA microspheres and PLA powder were added to alumina ceramic slurry and stirred in a sealed container for 10 h to mix them evenly. The mass ratio of alumina ceramic slurry to PMMA / PLA was 97:3, the mass ratio of PMMA to PLA was 1:3, the solid content of alumina ceramic slurry was 80%, the particle size of α-Al2O3 was 5 μm, the particle size of PMMA microspheres was 5 μm, and the particle size of PLA powder was 15 μm. The stirring speed was 300 r / min.

[0079] (2) Printing: Use 3D modeling software to draw a printable model, then import the 3D model into the computer control system to generate G-code. Use a sinking DLP device, a dual-channel LED light source with a wavelength of 405nm, a light intensity setting of 60%, a layer thickness of 10μm, a base exposure time of 2000ms, a normal layer exposure time of 1000ms, and a scraping speed of 60mm / s. Print layer by layer and accumulate to obtain an alumina / PMMA / PLA ceramic body. CAD, UG, Solidworks, and other software can be used for modeling.

[0080] (3) Drying and sintering of the green body: The green body obtained in step (2) was dried in a drying oven at 80°C for 24 hours, and then placed in a muffle furnace for sintering. Specifically, the temperature was raised from room temperature to 500°C at a rate of 5°C / min and kept at this temperature for 1 hour; then the temperature was raised to 600°C at a rate of 10°C / min and kept at this temperature for 2 hours to fully remove the pore-forming agent; finally, the temperature was raised to 1600°C at a rate of 15°C / min and kept at this temperature for 3 hours. Finally, the sample was naturally cooled to obtain the sample.

[0081] (4) The surface pore size of the product obtained by sintering the embodiment 2 is 30 μm, discrete, and non-connected. There are no obvious holes in the cross section, the room temperature flexural strength is between 265 MPa, the shrinkage rate in the XY direction is 9%, and the shrinkage rate in the Z direction is 12%. Figure 7 The Ra of area 1 shown is 9.892, and the microstructure is uniform.

[0082] Figure 5 This is a scanning electron micrograph of the cross section of the alumina ceramic sample prepared in Example 2, where the magnification is 500 times. Figure 6 This is a microscopic structure diagram of the sample surface in Example 2, where the magnification is 100 times. Figure 7 This is the surface roughness measurement diagram of the sample in Example 2.

[0083] During the experiment, the procedures of Examples 1 and 2 were followed. Microstructural observation of the prepared ceramic samples using scanning electron microscopy (SEM) revealed a uniformly distributed pore structure formed on the sample surface, with pore sizes ranging from 2 to 30 μm, consistent with the expected target. No obvious pores were found in the cross-section of the ceramic samples, indicating that the structure remained dense.

[0084] Surface roughness measurements of the samples were performed using a surface roughness meter. The results showed that the surface roughness Ra could be effectively controlled within a range of 0.8-20 under varying pore-forming agent addition ratios and printing parameter settings. Sample dimensions were also measured using calipers and compared to pre-printing design dimensions. Calculated shrinkage was less than 10%, demonstrating that the high solids content and rapid heating process effectively controlled sample shrinkage.

[0085] In terms of mechanical properties testing, the mechanical properties of ceramic samples were evaluated using methods such as the three-point bending test. The results showed that since the cross-section remained dense and the bending strength was 250-350 MPa, the mechanical properties were not significantly reduced due to surface pores.

[0086] In summary, the experimental results fully demonstrate that the present invention can successfully prepare ceramic samples with the expected surface pore structure, controllable surface roughness, low shrinkage rate and good mechanical properties by adding a specific proportion of pore-forming agent, using DLP 3D printing technology combined with high solid content and rapid heating treatment method. The technical solution is feasible and the effect is excellent.

[0087] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a porous bioceramic, characterized in that: The steps include: mixing alumina slurry with a pore-forming agent to obtain a mixed slurry; Using digital light processing technology in a layer-by-layer projection manner, the mixed slurry undergoes a light-curing reaction, and is printed and formed layer by layer to obtain a ceramic body; The ceramic body is subjected to high temperature treatment to obtain the porous bioceramic.

2. The method for preparing the porous bioceramic according to claim 1, wherein: The step of mixing the alumina slurry and the pore-forming agent to obtain the mixed slurry specifically includes the following steps: dispersing the pore-forming agent in the alumina slurry by stirring or ultrasonic dispersion.

3. The method for preparing the porous bioceramic according to claim 2, wherein: The solid content of the alumina slurry is 80%, and the particle size of α-Al2O3 is 1-5 μm.

4. The method for preparing the porous bioceramic according to claim 3, wherein: The mass ratio of the pore-forming agent to the alumina slurry is 2:98 or 3:

97. The pore-forming agent is a mixture of polymethyl methacrylate and polylactic acid. The mass ratio of the polymethyl methacrylate to the polylactic acid is 1:

3.

5. The method for preparing the porous bioceramic according to claim 4, wherein: The particle size of the polymethyl methacrylate is 3-5 μm, and the particle size of the polylactic acid is 5-15 μm.

6. The method for preparing the porous bioceramic according to claim 3, wherein: The pore-forming agent is an organic polymer material or a soluble salt. The organic polymer material includes polyvinyl alcohol or polyethylene glycol, and the soluble salt includes sodium chloride or ammonium chloride.

7. The method for preparing the porous bioceramic according to claim 1, wherein: The step of using digital light processing technology to project layer by layer to cause the mixed slurry to undergo a photocuring reaction, and printing and accumulating the slurry layer by layer to obtain a ceramic body specifically includes the following steps: placing the mixed slurry in a material tank of a DLP photocuring 3D printer, projecting a pre-designed model layer by layer through a computer-controlled digital light processing system, causing the slurry to undergo a photocuring reaction in a specific area, and printing and accumulating the slurry layer by layer to obtain a ceramic body.

8. The method for preparing the porous bioceramic according to claim 7, wherein: In the above molding process, a dual-channel LED light source with a wavelength of 405nm was used. The printing parameters included: light intensity was set to 60%, layer thickness was 10μm, base exposure time was 2000ms, common layer exposure time was 1000ms, and scraping speed was 60mm / s.

9. The method for preparing the porous bioceramic according to claim 1, wherein: The step of subjecting the ceramic body to high temperature treatment to obtain the porous bioceramic specifically includes the following steps: The ceramic body is dried at 30-80°C for 12-24 hours, and then the dried ceramic body is sintered. The sintering specifically includes: heating from room temperature to 500°C at a rate of 5°C / min, keeping warm for 1 hour; then heating to 600°C at a rate of 10°C / min, keeping warm for 2 hours; finally, heating to 1400-1600°C at a rate of 10-15°C / min, keeping warm for 2-3 hours, and finally naturally cooling to obtain the porous bioceramic.

10. The method for preparing the porous bioceramic according to claim 1, wherein: The surface of the porous bioceramic has a pore structure of 2-30 μm and a surface roughness Ra within the range of 0.8-20.

11. A porous bioceramic, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 10.

12. Use of the porous bioceramic according to claim 11 in bone tissue engineering scaffolds and tooth repair materials.

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