Porous Al2O3 ceramic with multi-scale pores and preparation method thereof
Porous Al2O3 ceramics were prepared by 3D printing and foam infusion, which solved the problem of difficult balance between mechanical and thermal insulation properties of porous ceramics and achieved multi-scale porous ceramic materials with low thermal conductivity and good mechanical properties.
Patent Information
- Application Number
- CN202510911450.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-10-17
AI Technical Summary
Existing technologies make it difficult to achieve a balance between mechanical properties and thermal insulation properties when preparing porous ceramics, and it is difficult to accurately control the pore topology of porous ceramics, resulting in large dispersion of material strength.
3D printing technology is used to prepare an Al2O3 skeleton with a lattice structure, and combined with the foam injection method, a porous ceramic material composed of millimeter-level pores and micron-level random pores is prepared. Its mechanical properties are controlled by changing the skeleton structure.
Low thermal conductivity and good mechanical properties are achieved. The mechanical properties can be controlled by adjusting the skeleton structure to prepare interpenetrating porous ceramics with multi-scale pores.
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Figure CN120794584A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of porous ceramic preparation, and particularly relates to a porous Al2O3 ceramic with multi-scale pores and a preparation method thereof. BACKGROUND
[0002] Due to the existence of a large number of covalent bonds and ionic bonds in the ceramic material, the ceramic material has many excellent physical and chemical properties that metal and polymer materials do not have, such as high hardness, high strength, good thermal shock resistance, chemical stability, high temperature resistance, corrosion resistance, etc. When the ceramic material is introduced into a porous structure, it will exhibit more unique performance and unique application. Porous ceramic is a kind of high porosity material with interconnected or closed pore structure, which has the advantages of low bulk density, uniform pore size distribution, good heat resistance, etc. and can be used as a functional material for heat preservation, filtration, sound absorption, etc.
[0003] In order to prepare porous ceramics with excellent performance, so far there have been many methods: gel method, pore-forming agent method, freeze-drying method, additive manufacturing, etc. The prior art can prepare porous ceramics with super-high porosity, extremely low thermal conductivity and other excellent properties. However, as the porosity of the porous ceramic increases, although its thermal insulation performance will be significantly improved, its mechanical properties will also decrease. Therefore, it has become a major problem in the field of porous ceramics to prepare porous ceramics with low thermal conductivity and good mechanical properties.
[0004] In the prior art, the traditional preparation method can prepare porous ceramics with extremely high porosity, but it is difficult to precisely control the foaming process and to prepare porous ceramics with precise pore topology, resulting in anisotropy of the mechanical properties of the material and large strength dispersion. The emerging additive manufacturing technology can accurately manufacture porous ceramics with complex and precise pores by computer control of the manufacturing process, so that the porous ceramics have good and controllable mechanical properties. However, this technology is limited by the current printing resolution and interlayer bonding strength, and the characteristic pore size of the formed components is mostly in the millimeter range, making it difficult to obtain excellent thermal insulation performance. SUMMARY
[0005] The present application aims to provide a porous Al2O3 ceramic with multi-scale pores and a preparation method thereof, to solve the problems of difficult trade-off between mechanical and thermal insulation performance and difficult control of mechanical properties in the prior art. The interpenetrating phase porous ceramic with multi-scale pores prepared by the present application has low thermal conductivity and good mechanical properties, and its mechanical properties can be controlled by changing the skeleton structure.
[0006] In a first aspect, the present application provides a porous ceramic material composed of a lattice structure skeleton with a millimeter-scale pore size and a porous ceramic matrix with a micrometer-scale random pore.
[0007] In a second aspect, the present application provides a method for preparing the porous ceramic material as described above, comprising the following steps:
[0008] preparing an Al2O3 skeleton with a lattice structure and an Al2O3 wet foam, respectively;
[0009] pouring the Al2O3 wet foam into a mold, immersing the Al2O3 skeleton into the Al2O3 wet foam, and then performing vacuum exhaust, drying and demolding to obtain an Al2O3 ceramic green body;
[0010] performing sintering on the Al2O3 ceramic green body after degassing at 250-500°C, and then heating to above 1600°C at a rate of 2-8°C / min to obtain the porous ceramic material.
[0011] Preferably, the Al2O3 skeleton with a lattice structure is prepared by a light-cured printing method.
[0012] Preferably, the relative density of the Al2O3 skeleton is 0.2-0.4, which is the density of the Al2O3 skeleton relative to the density of conventional Al2O3 powder, and the density of conventional Al2O3 powder is 3.98 g / cm 3 .
[0013] Preferably, the lattice structure comprises a two-dimensional lattice structure and a three-dimensional lattice structure.
[0014] Preferably, the two-dimensional lattice structure comprises a hexagonal honeycomb structure.
[0015] Preferably, the three-dimensional lattice structure comprises an octet truss structure, a Schoen I-WP TPMS structure and a Schwarz primitive TPMS structure.
[0016] Preferably, the method for preparing the Al2O3 wet foam comprises the following steps:
[0017] mixing Al2O3 powder with a gel agent, adding deionized water, and performing ball milling to obtain an Al2O3 suspension;
[0018] adding a foaming agent to the Al2O3 suspension, stirring at a speed of 1000-1500 rpm to generate bubbles in the suspension, and obtaining an Al2O3 wet foam.
[0019] Preferably, the gel agent is isobutylene-maleic anhydride copolymer (abbreviated as PIBM).
[0020] Preferably, the foaming agent is a cationic surfactant.
[0021] As a preferred solution, the cationic surfactant is at least one selected from the group consisting of dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride and hexadecyltrimethylammonium bromide.
[0022] As a preferred solution, the sintering temperature is 1600-1700℃.
[0023] Compared with the prior art, the present application has the following beneficial effects:
[0024] The present application prepares Al2O3 skeletons of octet truss structure, Schoen I-WP TPMS structure, Schwarz primitive TPMS structure and hexagonal honeycomb structure by 3D printing technology, and prepares interpenetrating phase porous ceramic materials with multi-scale pores by combining with the foam injection method. The interpenetrating phase porous ceramic material with multi-scale pores prepared by the present application has low thermal conductivity and good mechanical properties, and the mechanical properties can be controlled by changing the skeleton structure. BRIEF DESCRIPTION OF DRAWINGS
[0025] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:
[0026] Figure 1 The four interpenetrating phase porous ceramic materials with multi-scale pores prepared in Examples 1-4 of the present application are shown in the actual photographs; wherein, Figure 1 a is an actual photograph of the interpenetrating phase porous Al2O3 ceramic material with multi-scale pores and octet truss structure as the skeleton (Example 1), Figure 1 b is an actual photograph of the interpenetrating phase porous Al2O3 ceramic material with multi-scale pores and hexagonal honeycomb structure as the skeleton (Example 2), Figure 1 c is an actual photograph of the interpenetrating phase porous Al2O3 ceramic material with multi-scale pores and Schoen I-WP TPMS structure as the skeleton (Example 3), Figure 1 d is an actual photograph of the interpenetrating phase porous Al2O3 ceramic material with multi-scale pores and Schwarz primitive TPMS structure as the skeleton (Example 4), Figure 1 e and Figure 1 f is a scanning electron microscope photograph of the interpenetrating phase porous Al2O3 ceramic material with multi-scale pores prepared in Example 1;
[0027] Figure 2 The compression strength and Young's modulus results of Examples 1-4 and Comparative Examples 1-5 of the present application are shown in the graphs; wherein Figure 2 a is a compression strength graph, Figure 2 b is a Young's modulus graph;
[0028] Figure 3 Equivalent thermal conductivity results chart for Examples 1-4 and Comparative Examples 1-5 of the present application. DETAILED DESCRIPTION
[0029] The application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the application, but in no way limit the application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These are within the scope of the present application.
[0030] The Al2O3 slurry used in the present application is CPA-012 type slurry produced by Jiaxing Raoli Technology Co., Ltd.
[0031] Example 1
[0032] The present embodiment provides a method for preparing porous Al2O3 ceramic with multi-scale pores, comprising the following steps:
[0033] (1) Skeleton printing: using a DLP 3D printer to print a designed dot matrix structure, and using Al2O3 slurry to prepare an Al2O3 skeleton with an octet truss structure;
[0034] (2) Preparation of suspension: 50g of Al2O3 powder is mixed with 0.15g of PIBM and then placed in a ball mill tank, 18.84g of deionized water is added and ball milled to obtain an Al2O3 suspension;
[0035] (3) Preparation of wet foam: adding dodecyl trimethyl ammonium chloride to the Al2O3 suspension, and then using a mechanical stirrer to stir at a speed of 1000 rpm for 5 min to generate bubbles in the suspension, obtaining an Al2O3 wet foam;
[0036] (4) Preparation of green body: pouring the wet foam of step (3) into a mold, and then immersing the Al2O3 skeleton of step (1) into the Al2O3 wet foam, placing it in a vacuum box and vacuumizing for 20 min, then naturally drying, and after drying, demolding to obtain an interpenetrating phase porous Al2O3 ceramic green body with multi-scale pores;
[0037] (5) Degassing and sintering: placing the green body of step (4) into a muffle furnace, heating to 500℃, holding for 1h to degas, and then continuing to heat to 1650℃ at a rate of 5℃ / min to sinter, and after natural cooling, obtaining an interpenetrating phase porous Al2O3 ceramic material with an octet truss structure as a skeleton and multi-scale pores.
[0038] Example 2
[0039] This example provides a method for preparing a porous Al2O3 ceramic having multi-scale pores, which differs from Example 1 only in that the structure of the Al2O3 skeleton in step (1) is a hexagonal honeycomb structure.
[0040] Example 3
[0041] This example provides a method for preparing a porous Al2O3 ceramic having multi-scale pores, which differs from Example 1 only in that the structure of the Al2O3 skeleton in step (1) is a Schoen I-WP TPMS structure.
[0042] Example 4
[0043] This example provides a method for preparing a porous Al2O3 ceramic having multi-scale pores, which differs from Example 1 only in that the structure of the Al2O3 skeleton in step (1) is a Schwarz primitive TPMS structure.
[0044] Comparative Example 1
[0045] This comparative example differs from Example 1 only in that the Al2O3 skeleton is not prepared.
[0046] Comparative Example 2
[0047] This comparative example differs from Example 1 only in that the Al2O3 wet foam is not added in the preparation of the Al2O3 ceramic green body.
[0048] Comparative Example 3
[0049] This comparative example differs from Comparative Example 2 only in that the structure of the Al2O3 skeleton is a hexagonal honeycomb structure.
[0050] Comparative Example 4
[0051] This comparative example differs from Comparative Example 2 only in that the structure of the Al2O3 skeleton is a Schoen I-WP TPMS structure.
[0052] Comparative Example 5
[0053] This comparative example differs from Comparative Example 2 only in that the structure of the Al2O3 skeleton is a Schwarz primitive TPMS structure.
[0054] Effect Example
[0055] The products of Examples 1 to 4 and Comparative Examples 1 to 5 of the present application were subjected to the following performance tests:
[0056] 1. Compression test: A microcomputer-controlled electronic universal testing machine is used to test the product at a compression speed of 0.5 mm / min, and the mechanical properties of the product are analyzed through stress-strain curves.
[0057] 2. Thermal conductivity test: Use the guarded heat flow meter method, with the cold plate temperature at 25°C and the hot plate temperature at 70°C. After the temperature stabilizes, perform the thermal conductivity test on the product.
[0058] from Figure 1 It can be seen that four interpenetrating porous Al2O3 ceramic materials with multi-scale pores in Examples 1 to 4 were successfully prepared, among which Figure 1 As can be seen from e, there are many small pores in the middle of the multi-scale pore interpenetrating porous Al2O3 ceramic material obtained in Example 1. Figure 1 It can be seen from Figure f that there are many pores in the middle and edge junctions of the interpenetrating porous Al2O3 ceramic material with multi-scale pores obtained in Example 1.
[0059] Based on the compression test, the mechanical properties of Examples 1 to 4 and Comparative Examples 1 to 5 are as follows: Figure 2 As shown, the results show that the mechanical properties of the four interpenetrating porous Al2O3 ceramic materials with multi-scale pores are affected by the mechanical properties of their internal skeletons, so changing the skeleton structure can change the mechanical properties of the interpenetrating porous Al2O3 ceramic materials with multi-scale pores.
[0060] The mechanical properties of the products prepared in Examples 1 to 4 were compared. Influenced by the hexagonal honeycomb structure skeleton, the product prepared in Example 2 had the best mechanical properties, with a compressive strength of 153 MPa and a Young's modulus of 1962 MPa.
[0061] Based on the thermal conductivity test, the thermal conductivity test results of Examples 1 to 4 and Comparative Examples 1 to 5 are as follows: Figure 3 As shown, the results show that the thermal conductivity of the four interpenetrating porous Al2O3 ceramic materials with multi-scale pores is less than 1W / (m·K), which is a low thermal conductivity material and has the potential to be used as a thermal insulation material.
[0062] Comparing Examples 1 to 4 with Comparative Examples 1 to 5, Examples 1 to 4 all have thermal conductivities lower than those of their single-phase components, indicating that the preparation process of the present invention optimizes the thermal insulation performance of each phase material in the products of Examples 1 to 4.
[0063] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.
Claims
1. A porous Al2O3 ceramic with multi-scale pores, characterized in that: It consists of a lattice structure Al2O3 skeleton with millimeter-level pores and an Al2O3 porous ceramic matrix with micron-level random pores.
2. A method for preparing porous Al2O3 ceramics having multi-scale pores according to claim 1, characterized in that: The steps include: Al2O3 skeletons and Al2O3 wet foams with lattice structures were prepared respectively; Pour the Al2O3 wet foam into a mold, immerse the Al2O3 skeleton in the Al2O3 wet foam, and perform vacuum degassing, drying, and demolding to obtain an Al2O3 ceramic green body; The Al2O3 ceramic green body is subjected to binder removal at 250°C to 500°C, and then heated to above 1600°C at a rate of 2°C / min to 8°C / min, and sintered to obtain the porous ceramic material.
3. The method for preparing porous Al2O3 ceramics having multi-scale pores according to claim 2, characterized in that: The preparation method of the Al2O3 skeleton with a lattice structure is a photocuring printing method.
4. The method for preparing porous Al2O3 ceramics having multi-scale pores according to claim 2, characterized in that: The relative density of the Al2O3 skeleton is 0.2 to 0.
4.
5. The method for preparing porous Al2O3 ceramics with multi-scale pores according to claim 2, characterized in that: The lattice structure includes a two-dimensional lattice structure and a three-dimensional lattice structure.
6. The method for preparing porous Al2O3 ceramics having multi-scale pores according to claim 5, characterized in that: The two-dimensional lattice structure includes a hexagonal honeycomb structure.
7. The method for preparing porous Al2O3 ceramics with multi-scale pores according to claim 5, characterized in that: The three-dimensional lattice structure includes an octet truss structure, a SchoenI-WP TPMS structure, and a Schwarz primitive TPMS structure.
8. The method for preparing porous Al2O3 ceramics with multi-scale pores according to claim 2, characterized in that: The preparation method of the Al2O3 wet foam is: After mixing Al2O3 powder and gelling agent, deionized water is added and ball milled to obtain Al2O3 suspension; A foaming agent is added to the Al2O3 suspension, and the suspension is stirred at a speed of 1000 rpm to 1500 rpm to generate bubbles in the suspension to obtain Al2O3 wet foam.
9. The method for preparing porous Al2O3 ceramics having multi-scale pores according to claim 8, characterized in that: The gelling agent is isobutylene-maleic anhydride copolymer.
10. The method for preparing porous Al2O3 ceramics with multi-scale pores according to claim 8, characterized in that: The foaming agent is a cationic surfactant.
11. The method for preparing porous Al2O3 ceramics with multi-scale pores according to claim 2, characterized in that: The sintering temperature is 1600-1700°C.