CN111908922A - Low-temperature synthesized rare earth hafnate high-entropy ceramic powder and preparation method thereof - Google Patents
Low-temperature synthesized rare earth hafnate high-entropy ceramic powder and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a low-temperature synthesized rare earth hafnate high-entropy ceramic powder and a preparation method thereof, wherein the chemical formula of the rare earth hafnate high-entropy ceramic is (5 RE)0.2)2Hf2O7Wherein, the rare earth element RE is La, Ce, Nd, Pr, Sm and Eu. The preparation process of the invention is as follows: with hafnium tetrachloride (HfCl)4) And hydrated rare earth nitrate (RE (NO)3)3·xH2O) as raw material, urea as combustion agent, through solution mixing, in air atmosphere and low temperature, the fluffy powder is generated through combustion, and after high temperature decarbonization treatment, the high purity (5 RE) is obtained0.2)2Hf2O7And (3) powder. Compared with high-energy ball milling, spray pyrolysis, coprecipitation and other oxide high-entropy ceramic synthesis methods, the method has the advantages of low synthesis temperature, simplicity in operation, high preparation speed and the like.
Description
Technical Field
The invention belongs to the field of powder synthesis, and relates to a high-entropy ceramic powder of rare earth hafnate synthesized at low temperature and a preparation method thereof.
Background
High Entropy Ceramics (HECs), sometimes also referred to as high entropy compounds, are single phase ceramics containing not less than four cations and anions. The concept of the high-entropy ceramic is derived from high-entropy alloy, and the high-entropy alloy shows excellent characteristics such as high strength and high hardness, so that the high-entropy ceramic becomes a hot spot of research in recent years. The high-entropy ceramic has high hardness, low thermal conductivity and electric conductivity, excellent dielectric property and excellent lithium ion cycle stability, so that the high-entropy ceramic can be widely applied as a wear-resistant material, a thermal protection material, a dielectric material and a lithium battery anode material. At the same time, pyrochlore-structured RE2Hf2O7Under the condition of high temperature, the material has the advantages of extremely low thermal conductivity, excellent phase stability, small thermal expansion coefficient change and the like, and is generally considered as a novel thermal barrier coating material with a very good application prospect.
At present, the research on oxide high-entropy ceramics is less, and the preparation process mainly comprises the following steps: the preparation methods have the defects of high energy consumption, long production period, high equipment requirement, complex process and the like, so that the combustion method has very wide development prospect as a low-temperature ceramic synthesis technology with simple process and short preparation period.
Document 1 "z.zhao, h.xiang, f.dai, et al, (la.zhao, h.xiang, f.dai, et al., (la.zhao)0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7:A novel high-entropy ceramic with low thermal conductivity and sluggish grain growth rate[J].Journal of Materials Science&Technology,2019.35(11):2647-2651. "preparation of high entropy ceramics (La) by coprecipitation0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7The calcination and sintering temperatures in the preparation process are 1300 ℃ and 1500 ℃ respectively, the preparation temperature of the method is high, and in addition, the addition of the precipitator can cause the local concentration to be too high, the agglomeration is generated or the composition is not uniform enough.
In the document 2, "K.Chen, X.Pei, L.Tang, et al, A five-component agglomerated fluoride [ J ]. Journal of the European Ceramic Society,2018.38(11): 4161-.
Document 3 "chelalli, m.r., et al," On the homogeneity of high-entry oxides: An innovative growth at the atomic scale [ J ]. Scripta materials, 2019.166:58-63, "using spray pyrolysis method to prepare a variety of single-phase oxide high-entropy ceramics having perovskite structure, the process being carried out at a temperature of 1150 ℃ to 1250 ℃ and a pressure of 900mbar, which process requires high equipment and increases production costs.
Disclosure of Invention
Technical problem to be solved
In order to avoid the defects of the prior art, the invention provides the high-entropy ceramic powder for synthesizing the rare earth hafnate at low temperature and the preparation method thereof, and solves a plurality of problems in the preparation process. The molten salt method has the advantages of low preparation temperature, short heat preservation time, simple operation, good controllability of the components and the shape of the obtained powder, high activity of the powder and the like, and becomes a ceramic powder synthesis technology with wide development prospect.
Technical scheme
The low-temperature synthesized rare earth hafnate high-entropy ceramic powder is characterized in that: the rare earth hafnate high-entropy ceramic has the chemical formula of (5)RE0.2)2Hf2O7Wherein, the rare earth element RE is La, Ce, Nd, Pr, Sm and Eu; the powder particles are as small as 100nm and have pyrochlore structure characteristics.
The preparation method of the low-temperature synthesized rare earth hafnate high-entropy ceramic powder is characterized by comprising the following steps:
step 1, preparing a hafnium nitrate solution: dissolving hafnium tetrachloride powder in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate in a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and stirring while heating until a clear solution is obtained;
step 2: weighing hydrated rare earth nitrate according to the molar ratio of the hafnium element to the rare earth element of 1:1, and adding the RE (NO) containing five rare earth elements with the same molar ratio into the hafnium nitrate solution obtained in the step 13)3(ii) a Adding a combustion agent into the mixed solution according to the valence equilibrium principle of the oxidation-reduction reaction; placing the beaker filled with the mixed solution in a water bath constant-temperature magnetic stirrer at the temperature of 70-90 ℃, heating and stirring until the solution is clear, and simultaneously adjusting the pH value of the solution to 1-5; the hydrated rare earth nitrate RE (NO)3)3·xH2O,RE＝La,Ce,Nd,Pr,Sm,Eu；
And step 3: heating the preheated solution prepared in the step 2 at the combustion reaction temperature of 400-600 ℃ for 0.5-1 h, and after the solvent is completely evaporated to dryness, carrying out violent combustion reaction on the remaining colloidal substances to generate fluffy powder; and carrying out high-temperature heat treatment on the obtained powder at 800-1200 ℃ for 1-3 h, and removing redundant residual carbon to obtain the high-purity rare earth hafnate high-entropy ceramic powder with good crystallinity.
The hydrated rare earth nitrate (RE (NO)3)3·xH2O) comprises: hydrated lanthanum nitrate La (NO)3)3·xH2Cerium nitrate O, hexahydrate Ce (NO)3)3·6H2Nd (NO) nitrate of O, hexahydrate3)3·6H2O, praseodymium nitrate hexahydrate Pr (NO)3)3·6H2O, samarium nitrate hexahydrate Sm (NO)3)3·6H2O and europium nitrate hexahydrate Eu (NO)3)3·6H2And O, wherein the hydrated rare earth nitrates are calculated according to molar ratio, and the ratio of the optional five rare earth nitrates is 1:1:1:1: 1.
The combustion agent is urea CO (NH)2)2The purity is analytical purity, and the ratio of the hafnium tetrachloride to the urea is 1: 1.5-3 in terms of mass ratio.
Advantageous effects
The invention provides a low-temperature synthesized rare earth hafnate high-entropy ceramic powder and a preparation method thereof, wherein the chemical formula of the rare earth hafnate high-entropy ceramic is (5 RE)0.2)2Hf2O7Wherein, the rare earth element RE is La, Ce, Nd, Pr, Sm and Eu. The preparation process of the invention is as follows: with hafnium tetrachloride (HfCl)4) And hydrated rare earth nitrate (RE (NO)3)3·xH2O) as raw material, urea as combustion agent, through solution mixing, in air atmosphere and low temperature, the fluffy powder is generated through combustion, and after high temperature decarbonization treatment, the high purity (5 RE) is obtained0.2)2Hf2O7And (3) powder. Compared with high-energy ball milling, spray pyrolysis, coprecipitation and other oxide high-entropy ceramic synthesis methods, the method has the advantages of low synthesis temperature, simplicity in operation, high preparation speed and the like.
Preparation of (5 RE) according to the invention0.2)2Hf2O7The powder is mainly characterized in that: because the precursor exists in the form of solution, the process of high-energy ball milling and mixing is omitted, and the problems of energy consumption and time consumption are solved. According to the invention, the combustion agent urea is introduced, so that a violent redox reaction can be initiated in the solution under a low-temperature condition, the required ceramic powder can be simply and rapidly synthesized, and the defects of high energy consumption, long production period, high equipment requirement, complex process and the like in the conventional preparation process are overcome. In addition, the powder produced by the invention is fluffy, is not easy to agglomerate, has smaller particles, uniform powder size and high powder activity. FIG. 1 is a scheme of synthetic (5 RE)0.2)2Hf2O7The high-power morphology of the powder is shown in fig. 1, and the ceramic powder prepared by the invention has smaller particles (about 100nm) and uniform distribution; FIGS. 2 and 3 are synthetic (5 RE)0.2)2Hf2O7The XRD pattern and TEM high resolution pattern of the powder show that the ceramic powder prepared by the invention has obvious pyrochlore structure characteristics from figures 2 and 3.
Drawings
FIG. 1 is a scheme of synthetic (5 RE)0.2)2Hf2O7High power shape chart of powder
FIG. 2 is a scheme of synthetic (5 RE)0.2)2Hf2O7XRD pattern of powder
FIG. 3 is a TEM high resolution of synthesized (5RE0.2)2Hf2O7 powder
Detailed Description
The invention will now be further described with reference to the following examples and drawings:
the specific process of the invention is as follows:
step 1: preparation of hafnium nitrate solution: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: adding a hydrated rare earth element nitrate (RE (NO) containing five elements in the same molar ratio to the hafnium nitrate solution obtained in the step 13)3·xH2O, RE ═ La, Ce, Nd, Pr, Sm, Eu), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the valence equilibrium principle of the oxidation-reduction reaction, 1-1.5 times of urea which is calculated as required amount is added into the mixed solution to be used as a combustion agent. And (3) placing the beaker filled with the mixed solution into a water bath constant-temperature magnetic stirrer with the temperature of 70-90 ℃, heating and stirring until the solution is clear, and simultaneously adjusting the pH value of the solution to 1-5.
And step 3: placing the preheated beaker filled with the solution prepared in the step 2 on a flat heater at the temperature of 400-600 ℃ for heating for 0.5-1 h, wherein the solution is subjected to violent chemical reaction and generates a large amount of water vapor in the heating process, and after the solvent is completely evaporated to dryness, the residual colloidal substances are subjected to violent combustion reaction to generate fluffy powder; performing high-temperature heat treatment on the obtained powder at 800-1200 ℃ for 1-3 h, and removing redundant residual carbon to obtain high-purity rare earth hafnate high-entropy ceramic ((5RE hafnate) with good crystallinity0.2)2Hf2O7) And (3) powder.
Example 1:
in this example, the combustion method is adopted to prepare rare earth hafnate high-entropy ceramic ((La) and0.2Ce0.2Pr0.2Sm0.2Eu0.2)2Hf2O7) And (3) powder.
Step 1: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: to the obtained solution was added lanthanum nitrate hydrate (La (NO) containing the same molar ratio of rare earth elements3)3·xH2O), cerium nitrate hexahydrate (Ce (NO)3)3·6H2O), praseodymium nitrate hexahydrate (Pr (NO)3)3·6H2O), samarium nitrate hexahydrate (Sm (NO)3)3·6H2O) and europium nitrate hexahydrate (Eu (NO)3)3·6H2O), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the redox reaction valence balance principle, 1-1.5 times of urea which is used as a combustion agent in the required amount is added into the mixed solution, the beaker filled with the mixed solution is placed in a water bath constant-temperature magnetic stirrer with the temperature of 70-90 ℃, the mixture is stirred while being heated until the solution is clear, and meanwhile, the pH value of the solution is adjusted to 1-5.
And step 3: placing a beaker filled with the prepared mixed solution on a flat heater at the temperature of 400-600 ℃ for heating, obtaining tawny fluffy powder after combustion reaction, and obtaining high-purity (La) with good crystallinity after removing excessive carbon residue by high-temperature heat treatment at the temperature of 800-1200 ℃ of the obtained powder0.2Ce0.2Pr0.2Sm0.2Eu0.2)2Hf2O7And (3) powder.
Example 2:
in this example, the combustion method is adopted to prepare rare earth hafnate high-entropy ceramic ((La) and0.2Nd0.2Pr0.2Sm0.2Eu0.2)2Hf2O7) And (3) powder.
Step 1: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: to the solution obtained, lanthanum nitrate hexahydrate (La (NO) containing the same molar ratio of rare earth elements was added3)3·6H2O), rubidium nitrate hexahydrate (Nd (NO)3)3·6H2O), praseodymium nitrate hexahydrate (Pr (NO)3)3·6H2O), samarium nitrate hexahydrate (Sm (NO)3)3·6H2O) and europium nitrate hexahydrate (Eu (NO)3)3·6H2O), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the redox reaction valence balance principle, adding 1.2-1.8 times of urea as a combustion agent into the mixed solution, placing a beaker containing the mixed solution into a water bath constant-temperature magnetic stirrer at the temperature of 70-90 ℃, heating while stirring until the solution is clear, and adjusting the pH value of the solution to 1-5.
And step 3: mixing the prepared mixed solutionThe beaker is placed on a flat heater with the temperature of 400-600 ℃ and heated for 0.5-1 h, tawny fluffy powder is obtained after combustion reaction, the obtained powder is subjected to high-temperature heat treatment at the temperature of 800-1200 ℃ for 1-3 h, and after excessive carbon residue is removed, high-purity (La) with good crystallinity can be obtained0.2Nd0.2Pr0.2Sm0.2Eu0.2)2Hf2O7And (3) powder.
Example 3:
in this example, the combustion method is adopted to prepare rare earth hafnate high-entropy ceramic ((La) and0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Hf2O7) And (3) powder.
Step 1: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: to the obtained solution was added lanthanum nitrate hydrate (La (NO) containing the same molar ratio of rare earth elements3)3·xH2O), cerium nitrate hexahydrate (Ce (NO)3)3·6H2O), rubidium nitrate hexahydrate (Nd (NO)3)3·6H2O), samarium nitrate hexahydrate (Sm (NO)3)3·6H2O) and europium nitrate hexahydrate (Eu (NO)3)3·6H2O), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the redox reaction valence balance principle, 1-1.5 times of urea which is used as a combustion agent in the required amount is added into the mixed solution, the beaker filled with the mixed solution is placed in a water bath constant-temperature magnetic stirrer with the temperature of 70-90 ℃, the mixture is stirred while being heated until the solution is clear, and meanwhile, the pH value of the solution is adjusted to 1-5.
And step 3: placing the beaker filled with the prepared mixed solution on a flat heater at the temperature of 400-600 ℃ for heating for 0And 5-1 h, obtaining fluffy powder after combustion reaction, carrying out high-temperature heat treatment on the obtained powder at 800-1200 ℃ for 1-3 h, and removing excessive residual carbon to obtain high-purity (La) with good crystallinity0.2Ce0.2 Nd0.2Sm0.2Eu0.2)2Hf2O7And (3) powder.
Example 4:
in this example, the combustion method is adopted to prepare rare earth hafnate high-entropy ceramic ((La) and0.2Ce0.2Nd0.2Pr0.2Eu0.2)2Hf2O7) And (3) powder.
Step 1: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: to the obtained solution was added lanthanum nitrate hydrate (La (NO) containing the same molar ratio of rare earth elements3)3·xH2O), cerium nitrate hexahydrate (Ce (NO)3)3·6H2O), rubidium nitrate hexahydrate (Nd (NO)3)3·6H2O), praseodymium nitrate hexahydrate (Pr (NO)3)3·6H2O) and europium nitrate hexahydrate (Eu (NO)3)3·6H2O), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the redox reaction valence balance principle, 1-1.5 times of urea which is used as a combustion agent in the required amount is added into the mixed solution, the beaker filled with the mixed solution is placed in a water bath constant-temperature magnetic stirrer with the temperature of 70-90 ℃, the mixture is stirred while being heated until the solution is clear, and meanwhile, the pH value of the solution is adjusted to 1-5.
And step 3: placing a beaker containing the prepared mixed solution on a flat heater at the temperature of 400-600 ℃ to heat for 0.5-1 h, obtaining fluffy powder after combustion reaction, and obtaining the powder after 800E to EHigh-temperature heat treatment at 1200 ℃ for 1-3 h, and high-purity (La) with good crystallinity can be obtained after removing excessive carbon residue0.2Ce0.2Nd0.2Pr0.2Eu0.2)2Hf2O7And (3) powder.
Example 5:
in this example, the combustion method is adopted to prepare rare earth hafnate high-entropy ceramic ((La) and0.2Ce0.2Nd0.2Pr0.2Sm0.2)2Hf2O7) And (3) powder.
Step 1: weighing a certain mass of hafnium tetrachloride powder, dissolving in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; and repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate into a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and heating while stirring until a clear solution is obtained.
Step 2: to the obtained solution was added lanthanum nitrate hydrate (La (NO) containing the same molar ratio of rare earth elements3)3·xH2O), cerium nitrate hexahydrate (Ce (NO)3)3·6H2O), rubidium nitrate hexahydrate (Nd (NO)3)3·6H2O), praseodymium nitrate hexahydrate (Pr (NO)3)3·6H2O) and samarium nitrate hexahydrate (Sm (NO)3)3·6H2O), the molar stoichiometric ratio of the total amount of the required rare earth elements to the hafnium element is 1: 1; according to the redox reaction valence balance principle, 1-1.5 times of urea which is used as a combustion agent in the required amount is added into the mixed solution, the beaker filled with the mixed solution is placed in a water bath constant-temperature magnetic stirrer with the temperature of 70-90 ℃, the mixture is stirred while being heated until the solution is clear, and meanwhile, the pH value of the solution is adjusted to 1-5.
And step 3: placing a beaker filled with the prepared mixed solution on a flat heater at the temperature of 400-600 ℃ for heating for 0.5-1 h, obtaining tawny fluffy powder after combustion reaction, carrying out high-temperature heat treatment on the obtained powder at the temperature of 800-1200 ℃ for 1-3 h, removing redundant carbon residue, and obtaining the knotHigh purity (La) with good crystallinity0.2Ce0.2Nd0.2Pr0.2Sm0.2)2Hf2O7And (3) powder.
Claims (4)
1. The low-temperature synthesized rare earth hafnate high-entropy ceramic powder is characterized in that: the rare earth hafnate high-entropy ceramic has the chemical formula of (5 RE)0.2)2Hf2O7Wherein, the rare earth element RE is La, Ce, Nd, Pr, Sm and Eu; the powder particles are as small as 100nm and have pyrochlore structure characteristics.
2. The preparation method of the low-temperature synthesized rare earth hafnate high-entropy ceramic powder of claim 1, which is characterized by comprising the following steps:
step 1, preparing a hafnium nitrate solution: dissolving hafnium tetrachloride powder in deionized water, and fully stirring; dripping excessive ammonia water into the solution, and reacting for half an hour to obtain white flocculent precipitate; repeatedly standing and cleaning the obtained white precipitate for 4-5 times, then placing the beaker filled with the white precipitate in a water bath constant-temperature magnetic stirrer at the temperature of 50-80 ℃, adding excessive concentrated nitric acid, and stirring while heating until a clear solution is obtained;
step 2: weighing hydrated rare earth nitrate according to the molar ratio of the hafnium element to the rare earth element of 1:1, and adding the RE (NO) containing five rare earth elements with the same molar ratio into the hafnium nitrate solution obtained in the step 13)3(ii) a Adding a combustion agent into the mixed solution according to the valence equilibrium principle of the oxidation-reduction reaction; placing the beaker filled with the mixed solution in a water bath constant-temperature magnetic stirrer at the temperature of 70-90 ℃, heating and stirring until the solution is clear, and simultaneously adjusting the pH value of the solution to 1-5; the hydrated rare earth nitrate RE (NO)3)3·xH2O,RE＝La,Ce,Nd,Pr,Sm,Eu；
And step 3: heating the preheated solution prepared in the step 2 at the combustion reaction temperature of 400-600 ℃ for 0.5-1 h, and after the solvent is completely evaporated to dryness, carrying out violent combustion reaction on the remaining colloidal substances to generate fluffy powder; and carrying out high-temperature heat treatment on the obtained powder at 800-1200 ℃ for 1-3 h, and removing redundant residual carbon to obtain the high-purity rare earth hafnate high-entropy ceramic powder with good crystallinity.
3. The method of claim 2, wherein: the hydrated rare earth nitrate (RE (NO)3)3·xH2O) comprises: hydrated lanthanum nitrate La (NO)3)3·xH2Cerium nitrate O, hexahydrate Ce (NO)3)3·6H2Nd (NO) nitrate of O, hexahydrate3)3·6H2O, praseodymium nitrate hexahydrate Pr (NO)3)3·6H2O, samarium nitrate hexahydrate Sm (NO)3)3·6H2O and europium nitrate hexahydrate Eu (NO)3)3·6H2And O, wherein the hydrated rare earth nitrates are calculated according to molar ratio, and the ratio of the optional five rare earth nitrates is 1:1:1:1: 1.
4. The method of claim 2, wherein: the combustion agent is urea CO (NH)2)2The purity is analytical purity, and the ratio of the hafnium tetrachloride to the urea is 1: 1.5-3 in terms of mass ratio.
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| CN112573921A (en) * | 2020-12-08 | 2021-03-30 | 深圳大学 | Temperature-stable microwave dielectric high-entropy ceramic material with ultralow dielectric constant and preparation method and application thereof |
| CN114163232A (en) * | 2021-12-14 | 2022-03-11 | 内蒙古工业大学 | Single crystal high-entropy ceramic powder and preparation method thereof |
| CN114956820A (en) * | 2022-05-31 | 2022-08-30 | 西北工业大学 | Rare earth composite oxide porous high-entropy ceramic and preparation method and application thereof |
| CN114988869A (en) * | 2022-05-09 | 2022-09-02 | 厦门稀土材料研究所 | Rare earth medium-high entropy hafnate-based ceramic material and preparation method and application thereof |
| CN115010493A (en) * | 2022-05-31 | 2022-09-06 | 清华大学 | High-entropy pyrochlore dielectric ceramic material and preparation method and application thereof |
| CN115215666A (en) * | 2022-08-11 | 2022-10-21 | 哈尔滨工业大学 | Boron nitride/high-entropy ceramic oxide and composite coating for shielding neutrons and gamma rays and preparation method thereof |
| CN115448718A (en) * | 2022-09-20 | 2022-12-09 | 中国核动力研究设计院 | Europium hafnate material, preparation method and application |
| CN115572162A (en) * | 2022-04-29 | 2023-01-06 | 厦门稀土材料研究所 | Rare earth medium-high entropy hafnate ceramic material for controlling reactor neutron |
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| CN114163232B (en) * | 2021-12-14 | 2023-03-14 | 内蒙古工业大学 | Single crystal high-entropy ceramic powder and preparation method thereof |
| CN115572162A (en) * | 2022-04-29 | 2023-01-06 | 厦门稀土材料研究所 | Rare earth medium-high entropy hafnate ceramic material for controlling reactor neutron |
| CN114988869A (en) * | 2022-05-09 | 2022-09-02 | 厦门稀土材料研究所 | Rare earth medium-high entropy hafnate-based ceramic material and preparation method and application thereof |
| CN114988869B (en) * | 2022-05-09 | 2023-10-03 | 厦门稀土材料研究所 | Rare earth medium-high entropy hafnate-based ceramic material, and preparation method and application thereof |
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| CN115448718A (en) * | 2022-09-20 | 2022-12-09 | 中国核动力研究设计院 | Europium hafnate material, preparation method and application |
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