CN115141030A - One kind (LaCeSmEuNd) 2 Zr 2 O 7 Preparation method of high-entropy oxide ceramic aerogel - Google Patents

One kind (LaCeSmEuNd) 2 Zr 2 O 7 Preparation method of high-entropy oxide ceramic aerogel Download PDF

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CN115141030A
CN115141030A CN202210757122.XA CN202210757122A CN115141030A CN 115141030 A CN115141030 A CN 115141030A CN 202210757122 A CN202210757122 A CN 202210757122A CN 115141030 A CN115141030 A CN 115141030A
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lacesmeund
aerogel
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崔升
刘学宁
徐世玉
付俊杰
袁美玉
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Nanjing Tech University
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Abstract

The invention provides a novel compound (LaCeSmEuNd) 2 Zr 2 O 7 The preparation method of the high-entropy oxide ceramic aerogel comprises the following steps: preparing metal ion hydrolysate; the second step is that: introducing a rubber core dispersing agent; the third step: a coagulant is introduced. The fourth step: aging and replacement of the gel. The fifth step: drying of the wet gel. And a sixth step: and (4) heat treatment. The seventh step: an aerogel product is obtained. High-energy ball milling and high-temperature densification are avoided, and the aerogel product has low thermal conductivity and good high-temperature stability.

Description

One kind (LaCeSmEuNd) 2 Zr 2 O 7 Preparation method of high-entropy oxide ceramic aerogel
Technical Field
The invention belongs to a structural preparation means of high-entropy oxide, and relates to a (LaCeSmEuNd) 2 Zr 2 O 7 A preparation method of high-entropy oxide ceramic aerogel,in particular to a nano-structured material (LaCeSmEuNd) with high porosity, low thermal conductivity and good thermal stability 2 Zr 2 O 7 A high-entropy oxide aerogel complete block and a preparation method of an aerogel product thereof.
Background
As high energy consuming industries continue to develop, high temperature equipment and instruments face a harsh service thermal environment with high heat flux density, posing even greater challenges to thermal insulation materials. A. The 2 B 2 O 7 The type high-entropy oxide ceramic is a material which combines five or more than five cations on one sublattice through the assistance of external energy, has been proved to show lower thermal conductivity than low-component cations for many times due to stronger phonon scattering, has wide prospect in the field of heat insulation materials, and is expected to replace YSZ as a new-generation high-temperature heat insulation material.
However, the metal oxides are highly inert, and the temperature required for preparing defective fluorite type high-entropy ceramics by a typical solid phase method in the current research is about 1500 ℃, and raw material powder is required to be uniformly mixed by means of high-energy ball milling (refer to Journal of the European Ceramic Society,2018,38 (10): 3578-3584. And Journal of the European Ceramic Society,2020,40 (5): 2120-2129. And the like). Therefore, the synthesis energy consumption is high, the thermal diffusion coefficient is high due to the compact structure, the thermal conductivity is (0.75-1W/(m.K)), in addition, the crystallite dimension is in a micron order, and the performance of the crystallite can not meet the requirement of a heat insulation material. Thus, solution A 2 B 2 O 7 The high-entropy ceramic has high synthesis temperature and has important significance in further reducing the thermal conductivity.
Disclosure of Invention
The invention aims to provide a (LaCeSmEuNd) for overcoming the defects of the prior art 2 Zr 2 O 7 A preparation method of high-entropy oxide ceramic aerogel.
The technical scheme of the invention is as follows: aiming at the existing research foundation, the invention starts with the precursor raw material and prepares the inert metal oxide raw Material (MO) x ) Instead of metallic inorganic salts (MCl) x Or M (NO) 3 ) x ) By introducing a gel nucleus by sol-gel methodThe powder and coagulant, by means of supercritical drying, prepare a precursor with a three-dimensional nanoporous structure to reduce the formation temperature of high entropy while preserving the nanoporous structure that is beneficial for thermal insulation. The results from XRD and EDS-Mapping showed successful preparation (LaCeSmEuNd) 2 Zr 2 O 7 All cations are dissolved into crystal lattices in a solid mode and belong to high-entropy defect fluorite ceramics, and SEM results show that the prepared high-entropy ceramics are aerogel porous structures. Furthermore, (LaCeSmEuNd) 2 Zr 2 O 7 The high-entropy oxide ceramic aerogel has good blocking property. In the subsequent process, the thermal conductivity of the block sample prepared by tabletting annealing is 0.07-0.1W/(m.K), and compared with the thermal conductivity of the compact block reported at present, the thermal conductivity of the block sample has obvious advantages and excellent thermal stability.
The specific technical scheme of the invention is as follows: one kind (LaCeSmEuNd) 2 Zr 2 O 7 According to the preparation method of the high-entropy oxide ceramic aerogel, a high-entropy ceramic aerogel complete block with a nano-pore structure is prepared by regulating and controlling a preparation means, and an aerogel product obtained by grinding and tabletting the high-entropy ceramic aerogel complete block has low thermal conductivity and excellent thermal stability; the method comprises the following specific steps:
(1) Preparation of metal ion hydrolysate
Weighing ethanol and water in a certain proportion as solvents, weighing inorganic salts of La, ce, sm, eu, nd and Zr, putting into a beaker, stirring until the inorganic salts are completely dissolved, and preparing metal ion hydrolysate;
(2) Introduction of a gum core dispersing agent
After the metal salt is completely dissolved in the solvent, adding the dispersing agent into the metal ion hydrolysate, and continuously stirring to uniformly mix the dispersing agent and the colloidal nucleus to obtain a solution;
(3) Introduction of setting accelerators
Cooling and keeping the solution obtained in the step (2) at a certain temperature, then adding a coagulant into the solution, stirring the solution, and standing the solution to cause a gelation reaction;
(4) Aging and replacement of gels
Aging the obtained gel for a certain time, adding ethanol for solvent replacement, replacing fresh ethanol at a certain frequency for a certain time, and obtaining aged block-shaped wet gel;
(5) Drying of wet gels
Drying the wet gel obtained in the step (4) to obtain an amorphous precursor with a three-dimensional nanopore structure;
(6) Heat treatment of aerogels
The obtained amorphous precursor having a three-dimensional nanoporous structure is placed in a muffle furnace and heat-treated at a certain temperature for a certain period of time to obtain a precursor having a nanoporous structure (lace smend) 2 Zr 2 O 7 A high-entropy ceramic aerogel complete block;
(7) Obtaining aerogel articles
Will have a nanoporous structure (LaCeSmEuNd) 2 Zr 2 O 7 Grinding the high-entropy ceramic aerogel complete block, putting into a mold, tabletting, and annealing in a muffle furnace to obtain porous ceramic aerogel (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel articles.
Preferably, the metal inorganic salt in the step (1) is one of nitrate or chloride of La, ce, sm, eu, nd and Zr, and the molar ratio of the total amount of lanthanide elements (La, ce, sm, eu and Nd) to Zr is controlled to be 1. Preferably, the volume ratio of the ethanol to the water in the step (1) is (3.5-2) to 1; the molar concentration of the metal inorganic salt is (0.35-1) mol/L.
Preferably, the dispersant in the step (2) is polyacrylic acid; in the step (2), the molar ratio of the total molar amount of the metal inorganic salt to the dispersant is 1 (0.02-0.05).
Preferably, the solution in the step (3) is cooled and kept at a certain temperature of-5 ℃; the coagulant is 1, 2-propylene oxide; the mol ratio of the coagulant to the metal inorganic salt is (7-15): 1.
Preferably, the aging time in the step (4) is 8-24 h; the replacement time is 48 to 72 hours, and the solvent is replaced every 6 to 12 hours.
Preferably, the drying method in step (5) is CO 2 One of supercritical drying or ethanol supercritical drying to obtain a porous structure.
Preferably, the heat treatment temperature in the step (6) is 750-1150 ℃, the heating rate is 1-5 ℃/min, and the heat preservation time after the heat treatment temperature is reached is 0.5-3 h.
Preferably, the annealing temperature in the step (7) is 800-1200 ℃, and the annealing time is 1-3 h.
Has the advantages that:
(1) Compared with the high entropy forming temperature of 1500 ℃ reported in literature, the high entropy forming temperature of the invention is lower than 1000 ℃, and high-energy ball milling is not needed, thus reducing energy consumption;
(2) Prepared by the invention (LaCeSmEuNd) 2 Zr 2 O 7 The high-entropy ceramic aerogel keeps a complete massive shape;
(3) Compared with the prior isomorphous high-entropy ceramic thermal conductivity (1W/(m.K)), the invention obtains (LaCeSmEuNd) 2 Zr 2 O 7 The high-entropy ceramic has the characteristic of high porosity typical of aerogel, so that the thermal conductivity of an aerogel product after tabletting annealing is still as low as 0.07W/(m.K);
(4) Prepared by the invention (LaCeSmEuNd) 2 Zr 2 O 7 The aerogel products have better thermal stability at high temperature, which is extremely important for the nano heat insulation ceramics used in high temperature environment.
Drawings
FIG. 1 is a graph of samples of the amorphous precursor after drying and the high entropy ceramic aerogel monolith after calcination in example 1; (a) Amorphous precursor, (b) pattern of calcined ceramic aerogel monolith sample.
FIG. 2 is X-ray diffraction patterns of the high-entropy ceramic aerogels treated at different temperatures in examples 1 to 6.
FIG. 3 is the element distribution (EDS-Mapping) of the high entropy ceramic of example 1.
Fig. 4 is a microstructure of the high-entropy ceramic aerogel of example 1, demonstrating that it has an aerogel nanoporous structure.
Fig. 5 is a macroscopic photograph of the high-entropy ceramic aerogel product of example 3 before and after annealing, which proves that the high-entropy ceramic aerogel product has a good effect on improving the thermal stability of the nano heat-insulating ceramic structure.
Detailed Description
The invention is further illustrated by the following examples, without limiting the scope of protection.
Example 1
1. In a beaker, 7mL of ethanol and 3mL of deionized water (volume ratio of ethanol to water: 2.33: 1) were added, and 5mmol of ZrOCl was weighed 2 ·8H 2 O，1mmolLa(NO 3 ) 3 ·6H 2 O，1mmol Ce(NO 3 ) 3 ·7H 2 O，1mmol SmCl 3 ，1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring the O into an alcohol-water mixed solution (the molar concentration of the metal inorganic salt is 1 mol/L), and stirring until the O is completely dissolved to obtain a metal salt hydrolysate;
2. measuring 0.72g of polyacrylic acid (the molar ratio of the total metal salt to the polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to 5 ℃, dropwise adding 4.2ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 6;
4. and (3) aging the precursor wet gel for 24h at room temperature after attaching a preservative film, and then adding a solvent for replacement, wherein the solvent amount is based on the fact that the wet gel is not covered, the replacement time is 72h, and the solvent is replaced every 6 h.
5. Taking out the aged and displaced wet gel, and adding CO 2 Supercritical drying is carried out in a drying container, and an amorphous precursor is obtained (see fig. 1 (a), and the amorphous precursor is complete in blocks).
6. Placing the amorphous precursor into a muffle furnace, heating to 750 deg.C at a heating rate of 1 deg.C/min, and maintaining at 750 deg.C for 3h to obtain (LaCeSmEuNd) 2 Zr 2 O 7 The integral block of the high-entropy ceramic aerogel (see fig. 1 (b), which shows that the high-entropy ceramic aerogel obtained after calcination has good blocking performance), and the sample is found to be a single-phase crystalline substance (see fig. 2) after phase and element characterization (see fig. 3), and the sample is shown to be high-entropy ceramic. Microstructure tableSymbolize that the sample is a typical aerogel structure (see fig. 4).
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a mold, applying 10MPa pressure, and annealing at 800 deg.C for 1 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic blocks. The prepared high-entropy ceramic aerogel product is 2.825g/cm 3 The thermal conductivity at room temperature was 0.073W/(mK).
Example 2
1. 10mL of ethanol and 5mL of deionized water (volume ratio of ethanol to water: 2: 1) were added to a beaker, and 5mmol of ZrOCl was weighed 2 ·8H 2 O、1mmol LaCl 3 ·6H 2 O、1mmol CeCl 3 ·7H 2 O、1mmol SmCl 3 、1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring O (the molar concentration of the metal inorganic salt is 0.67 mol/L) into the alcohol-water mixed solution, stirring until the O is completely dissolved to obtain the metal salt hydrolysis solution
2. Weighing 0.85g of polyacrylic acid aqueous solution (the total molar amount of the metal salt and the volume ratio of the polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to 0 ℃, dropwise adding 5.6ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 8;
4. and (3) aging the wet gel at room temperature for 12h after attaching a preservative film, and then adding a solvent for replacement, wherein the solvent is replaced for 56h based on the fact that the solvent is not covered by the wet gel, and the solvent is replaced every 8 h.
5. Taking out the aged and displaced wet gel, and adding CO 2 And carrying out supercritical drying in a drying container to obtain the amorphous precursor.
6. Placing the amorphous precursor in a muffle furnace, heating to 950 deg.C at a heating rate of 2 deg.C/min, and maintaining at 950 deg.C for 2h to obtain (LaCeSmEuNd) 2 Zr 2 O 7 A complete block of high entropy ceramic aerogel.After phase and element characterization of the sample, the sample is found to be a single-phase crystalline substance (see fig. 2), and the elements are well retained, indicating that the sample is high-entropy ceramic. Microstructural characterization indicated that the sample was a typical aerogel structure.
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a grinding tool, applying 10MPa pressure, and annealing at 1000 deg.C for 2 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel whole block. The density of the prepared high-entropy ceramic aerogel product is 2.886g/cm 3 The thermal conductivity at room temperature was 0.097W/(mK).
Example 3
1. 15mL of ethanol and 6mL of deionized water (volume ratio of ethanol to water: 2.5: 1) were added to a beaker, and 5mmol of ZrOCl 2 ·8H 2 O、1mmol SmCl 3 、1mmol CeCl 3 ·7H 2 O、1mmol La(NO 3 ) 3 ·6H 2 O、1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring O (the molar concentration of the metal inorganic salt is 0.48 mol/L) into the alcohol-water mixed solution, stirring until the O is completely dissolved to obtain the metal salt hydrolysis solution
2. Weighing 1.45g of polyacrylic acid aqueous solution (the molar ratio of the total molar amount of the metal salt to the polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to-5 ℃, dropwise adding 8.4ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 12;
4. and (3) aging the wet gel at room temperature for 8h after attaching a preservative film, and then adding a solvent for replacement, wherein the solvent is replaced for 48h based on the fact that the solvent is not covered by the wet gel, and the solvent is replaced every 12 h.
5. Taking out the aged and displaced wet gel, and adding CO 2 And carrying out supercritical drying in a drying container to obtain the amorphous precursor.
6. Subjecting an amorphous precursorPlacing into a muffle furnace, heating to 1150 deg.C at a heating rate of 5 deg.C/min, and maintaining at 1150 deg.C for 0.5h to obtain a nano-porous structure (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel whole block. After phase and element characterization of the sample, the sample is found to be a single-phase crystalline substance (see fig. 2), and the elements are well retained, indicating that the sample is high-entropy ceramic. Microstructural characterization indicated that the sample was a typical aerogel structure.
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a grinding tool, applying 10MPa pressure, and annealing at 1200 deg.C for 1 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 In order to have the advantage of high-entropy ceramic block over high-entropy ceramic aerogel product in temperature resistance, the same method as the example is adopted (only the raw material is different, namely 5mmol of La (NO) 3 ) 3 ·6H 2 O and 5mmol ZrOCl 2 ·8H 2 O, the other synthesis means are the same) to prepare La 2 Zr 2 O 7 An aerogel article. The dimensional ratio is shown in fig. 5. The density of the prepared high-entropy ceramic aerogel product is 2.906g/cm 3 The thermal conductivity at room temperature was 0.12W/(mK).
Example 4
1. In a beaker, 7mL of ethanol and 3mL of deionized water (volume ratio of ethanol to water: 2.33: 1) were added, and 5mmol of ZrOCl 2 ·8H 2 O、1mmolLa(NO 3 ) 3 ·6H 2 O，1mmol Ce(NO 3 ) 3 ·7H 2 O、1mmol SmCl 3 、1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring O (the molar concentration of the metal inorganic salt is 1 mol/L) into the alcohol-water mixed solution, and stirring until the O is completely dissolved to obtain metal salt hydrolysate;
2. weighing 0.72ml of polyacrylic acid aqueous solution (the total molar amount of metal salt and the mass ratio of polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to 5 ℃, dropwise adding 4.2ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 6;
4. and (3) aging the wet gel at room temperature for 24h after attaching a preservative film, and then adding ethanol into the wet gel, wherein the ethanol is replaced for 72h on the basis of the fact that the wet gel is not covered, and the ethanol is replaced every 6 h.
5. And taking out the aged and replaced wet gel, and putting the wet gel into an ethanol drying container for supercritical drying to obtain the amorphous precursor.
6. Placing the amorphous precursor into a muffle furnace, heating to 750 deg.C at a heating rate of 2 deg.C/min, and maintaining at 750 deg.C for 3h to obtain a nano-porous structure (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel block. After phase and element characterization of the sample, the sample is found to be a single-phase crystalline substance (see fig. 2), and the elements are well retained, indicating that the sample is high-entropy ceramic. Microstructural characterization indicated that the sample was a typical aerogel structure.
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a grinding tool, applying 10MPa pressure, and annealing at 800 deg.C for 3 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic blocks. The prepared high-entropy ceramic aerogel product is 2.764g/cm 3 The thermal conductivity at room temperature was 0.07W/(mK).
Example 5
1. To a beaker, 14mL of ethanol and 5mL of deionized water (volume ratio of ethanol to water: 2.8: 1) were added, and 5mmol of ZrOCl was weighed 2 ·8H 2 O、1mmol LaCl 3 ·6H 2 O、1mmol CeCl 3 ·7H 2 O、1mmol SmCl 3 、1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring the O into an alcohol-water mixed solution, and stirring until the O is completely dissolved (the molar concentration of the metal inorganic salt is 0.53 mol/L) to obtain metal salt hydrolysate;
2. weighing 0.85g of polyacrylic acid aqueous solution (the total molar amount of the metal salt and the volume ratio of the polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to 0 ℃, dropwise adding 5.6ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 8;
4. and (3) aging the wet gel at room temperature for 12h after attaching a preservative film, and then adding a solvent into the wet gel for replacement, wherein the solvent is used for 56h based on the fact that the wet gel is not covered, and the solvent is replaced every 8 h.
5. And taking out the aged and replaced wet gel, and putting the wet gel into an ethanol drying container for supercritical drying to obtain the amorphous precursor.
6. Placing the amorphous precursor into a muffle furnace, heating to 950 deg.C at a heating rate of 3 deg.C/min, and maintaining at 950 deg.C for 2h to obtain a nano-porous structure (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel block. After phase and element characterization of the sample, the sample is found to be a single-phase crystalline material (see fig. 2), and the elements are well retained, indicating that the sample is a high-entropy ceramic. Microstructural characterization indicated that the sample was a typical aerogel structure.
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a grinding tool, applying 10MPa pressure, and annealing at 1000 deg.C for 2 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic blocks. The density of the prepared high-entropy ceramic aerogel product is 2.862g/cm 3 The thermal conductivity at room temperature was 0.082W/(mK).
Example 6
1. 20mL of ethanol and 6mL of deionized water (volume ratio of ethanol to water: 3.33: 1) were added to a beaker, and 5mmol of ZrOCl 2 ·8H 2 O、1mmol SmCl 3 、1mmol CeCl 3 ·7H 2 O、1mmol La(NO 3 ) 3 ·6H 2 O、1mmol EuCl 3 ·6H 2 O and 1mmol of NdCl 3 ·6H 2 Transferring the O into an alcohol-water mixed solution, and stirring until the O is completely dissolved (the molar concentration of the metal inorganic salt is 0.38 mol/L) to obtain a metal salt hydrolysate;
2. weighing 1.45g of polyacrylic acid aqueous solution (the molar ratio of the total molar amount of the metal salt to the polyacrylic acid is 1;
3. cooling the stirred metal hydrolysate in an ethanol-water mixed water bath to-5 ℃, dropwise adding 8.4ml of 1, 2-epoxypropane (the molar ratio of the 1, 2-epoxypropane to the metal salt is 12;
4. and (3) aging the wet gel at room temperature for 8h after attaching a preservative film, and then adding a solvent into the wet gel for replacement, wherein the solvent amount is based on the fact that the wet gel is not covered, and the replacement time is 48h, and the solvent is replaced every 12 h.
5. And taking out the aged and replaced wet gel, and putting the wet gel into an ethanol drying container for supercritical drying to obtain the amorphous precursor.
6. Placing the amorphous precursor into a muffle furnace, heating to 1150 deg.C at a heating rate of 5 deg.C/min, and maintaining at 1150 deg.C for 2h to obtain a nano-porous structure (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel block. After phase and element characterization of the sample, the sample is found to be a single-phase crystalline substance (see fig. 2), and the elements are well retained, indicating that the sample is high-entropy ceramic. Microstructural characterization indicated that the sample was a typical aerogel structure.
7. Will (LaCeSmEuNd) 2 Zr 2 O 7 Grinding high-entropy ceramic aerogel powder, placing into a grinding tool, applying 10MPa pressure, and annealing at 1200 deg.C for 1 hr to obtain (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic blocks. The prepared high-entropy ceramic aerogel product is 2.900g/cm 3 The thermal conductivity at room temperature was 0.114W/(mK).

Claims (9)

1. One kind (LaCeSmEuNd) 2 Zr 2 O 7 The preparation method of the high-entropy oxide ceramic aerogel comprises the following specific steps:
(1) Preparation of metal ion hydrolysate
Weighing ethanol and water in a certain proportion as solvents, weighing inorganic salts of La, ce, sm, eu, nd and Zr, putting into a beaker, stirring until the inorganic salts are completely dissolved, and preparing metal ion hydrolysate;
(2) Introduction of a gum core dispersing agent
Adding a dispersing agent into the metal ion hydrolysate, and continuously stirring to uniformly mix the dispersing agent and the colloidal nucleus to obtain a solution;
(3) Introduction of setting accelerators
Cooling the solution obtained in the step (2) and keeping the solution at a certain temperature, then adding a coagulant into the solution, stirring the solution, and standing the solution to cause gelation reaction;
(4) Aging and replacement of gels
After the obtained gel is aged for a certain time, adding ethanol for solvent replacement to obtain aged block-shaped wet gel;
(5) Drying of wet gels
Drying the wet gel obtained in the step (4) to obtain an amorphous precursor with a three-dimensional nanopore structure;
(6) Heat treatment of aerogels
Placing the obtained amorphous precursor with three-dimensional nano-pore structure into a muffle furnace, and after heat treatment at a certain temperature for a certain period of time, obtaining the amorphous precursor with nano-pore structure (LaCeSmEuNd) 2 Zr 2 O 7 A high-entropy ceramic aerogel complete block;
(7) Obtaining the aerogel product
Will have a nanoporous structure (LaCeSmEuNd) 2 Zr 2 O 7 Grinding the high-entropy ceramic aerogel complete block, putting into a mold, tabletting, and annealing in a muffle furnace to obtain porous ceramic aerogel (LaCeSmEuNd) 2 Zr 2 O 7 High entropy ceramic aerogel articles.
2. The method according to claim 1, wherein the inorganic salt of a metal in the step (1) is a nitrate or chloride salt of a metal.
3. The method according to claim 1, wherein the volume ratio of ethanol to water in step (1) is (3.5-2): 1; the molar concentration of the metal inorganic salt is (0.35-1) mol/L.
4. The method according to claim 1, wherein the dispersant in the step (2) is polyacrylic acid; in the step (2), the molar ratio of the total molar amount of the metal inorganic salt to the dispersant is 1 (0.02-0.05).
5. The method according to claim 1, wherein the solution is cooled and maintained at a temperature of-5 to 5 ℃ in the step (3); the coagulant is 1, 2-propylene oxide; the mol ratio of the coagulant to the metal inorganic salt is (7-15): 1.
6. The method according to claim 1, wherein the aging time in the step (4) is 8 to 24 hours; the replacement time is 48 to 72 hours, and the solvent is replaced every 6 to 12 hours.
7. The method according to claim 1, wherein the drying method in the step (5) is CO 2 Supercritical drying or ethanol supercritical drying.
8. The method according to claim 1, wherein the heat treatment temperature in the step (6) is 750 to 1150 ℃, the temperature increase rate is 1 to 5 ℃/min, and the holding time after the heat treatment temperature is reached is 0.5 to 3 hours.
9. The method according to claim 1, wherein the annealing temperature in the step (7) is 800 to 1200 ℃ and the annealing time is 1 to 3 hours.
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