A mesoporous high-entropy rare earth oxide fiber, its preparation method and application

Abstract

This invention belongs to the field of inorganic materials technology, specifically relating to a mesoporous high-entropy rare earth oxide fiber and its preparation method and application. The preparation method includes the following steps: (1) preparing a mixed solution of dimethylacetamide and anhydrous ethanol, and adding PEO- b -PS, stir to obtain micelle solution; (2) add metal salt to PEO- b (3) PVP is added to the above solution, the pH value is adjusted to 2.5-6.5, and the solution is stirred to obtain a spinning solution; (4) the obtained spinning solution is electrospun to obtain composite fibers; (5) the obtained fibers are calcined in segments under an air atmosphere to obtain mesoporous high-entropy rare earth oxide fibers. The mesoporous high-entropy rare earth oxide fibers of the present invention have a uniform mesoporous structure, regular fiber morphology, controllable pore size distribution, and can be rapidly densified at low temperature to obtain ceramics, which significantly improves the mechanical properties of ceramic materials.

Description

Technical Field

[0001] This invention belongs to the field of inorganic materials technology, specifically relating to a mesoporous high-entropy rare earth oxide fiber, its preparation method, and its application. Background Technology

[0002] High-entropy oxides, due to their unique structural stability and tunable electronic properties, have shown broad application prospects in catalysis, sensing, energy storage, and biomedicine. Among them, one-dimensional mesoporous nanofibers combine the compositional diversity of high-entropy oxides with the high specific surface area of ​​mesoporous materials. At the same time, their high aspect ratio structure provides a smooth channel for electron / mass transport and has good structural stability, thus becoming a research hotspot in the field of functional materials.

[0003] Currently, methods for preparing mesoporous nanofibers mainly include solvothermal methods, soft template methods, and electrospinning. However, these methods generally suffer from complex processes and poor controllability of mesoporous structures, making it difficult to achieve precise control over the mesoporous morphology. In recent years, single-micelle guided assembly strategies have attracted attention due to their ability to construct ordered mesoporous structures using composite micelles as basic units. Compared with traditional liquid crystal template methods, this strategy offers higher structural tunability and flexibility. However, how to achieve controllable assembly and growth of single micelles in one dimension remains a pressing problem to be solved in this field.

[0004] Electrospinning technology is widely used for the preparation of one-dimensional nanostructured materials due to its advantages such as simple operation, low cost, and strong component compatibility. This technology stretches polymer solutions into nanofibers using a high-voltage electrostatic field. However, combining it with a single-micelle guided assembly strategy to achieve the controllable preparation of high-entropy oxide nanofibers with ordered mesoporous structures has not yet been reported. In particular, how to utilize the synergistic co-assembly mechanism of amphiphilic surfactants or graft copolymers to simultaneously achieve the introduction of multiple components and the control of mesoporous structure during electrospinning remains a technological gap. Therefore, developing a simple and structurally controllable method for preparing mesoporous high-entropy rare earth oxide nanofibers has significant research value and industrial application potential. Summary of the Invention

[0005] The purpose of this invention is to provide a mesoporous high-entropy rare earth oxide fiber, its preparation method, and its applications. The process of this invention is simple, involving adjusting the properties of the polyethylene oxide-polystyrene block copolymer (PEO-). bThe interaction between PS template agent, PVP, and metal salt in solution allows for precise control of self-assembly behavior, enabling the accurate construction of high-entropy rare earth oxide fibers under an applied electric field. The resulting mesoporous high-entropy rare earth oxide fibers are characterized by uniform fiber diameter and large specific surface area, significantly improved sintering activity, and a sintering temperature that is 25-30% lower (300-400℃) compared to traditional methods, while also possessing excellent mechanical properties.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows: In a first aspect, embodiments of the present invention provide a method for preparing mesoporous high-entropy rare earth oxide fibers, comprising the following steps: (1) Prepare a mixed solution by mixing dimethylacetamide and anhydrous ethanol, and add polyethylene oxide-polystyrene block copolymer PEO- b -PS, magnetic stirring to completely dissolve it, to obtain a micelle solution; (2) Add the required metal salt to the PEO- obtained in step (1). b - A clear and transparent solution was obtained by stirring in a PS micelle solution; (3) Add polyvinylpyrrolidone (PVP) to the solution obtained in step (2), adjust the pH of the system to between 2.5 and 6.5, and stir magnetically for 4-12 hours to obtain a clear, transparent, and viscous spinning solution. (4) The spinning solution obtained in step (3) is electrospun, collected and dried with silicone paper to obtain composite fiber; (5) The fiber obtained in step (4) is calcined in segments in an air atmosphere to obtain mesoporous high-entropy rare earth oxide fiber.

[0007] Further, in step (1), the volume ratio of dimethylacetamide to anhydrous ethanol is 5:1-9:1, and the PEO- b - The concentration of the PS micelle solution was controlled at 5-10 mg / mL.

[0008] Further, in step (2), the PEO- b- The molecular weight of PS is 20,000-40,000 g / mol, and the polydispersity index is 1.06-1.15. The metal salt and PEO- b- The quality ratio of PS is 4:1-6:1; The metal salt is selected from at least four of the following: lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, lutetium nitrate, scandium nitrate, and yttrium nitrate, to form the A-site of the mesoporous high-entropy rare earth oxide fiber; The metal salt is one or more of zirconium acetylacetonate, hafnium acetylacetonate, niobium isopropoxide, tantalum isopropoxide, and tetrabutyl titanate, forming the B site of the mesoporous high-entropy rare earth oxide fiber.

[0009] Further, in step (3), the molecular weight of the polyvinylpyrrolidone is 108-165w, and its mass fraction relative to the whole system is 6-10%.

[0010] Furthermore, in step (4), the electrospinning process has the following spinning parameters: voltage of 17-21 kV, receiving distance of 15-25 cm, spinning speed of 0.5-0.8 mL / h, temperature of 25-35℃, and relative humidity not exceeding 25%.

[0011] Furthermore, in step (5), the air calcination process should be divided into three stages. The first stage involves raising the temperature to 320-350℃ at a rate not exceeding 2℃ / min and maintaining it for 1-2 hours to remove the template agent PEO- b -PS, the second stage continues to heat to 500-600℃ at the same heating rate to remove PVP and complete metal oxidation, the third stage heats to 600-1000℃ at 5-10℃ / min to obtain mesoporous high-entropy rare earth oxide fibers.

[0012] Secondly, embodiments of the present invention provide a mesoporous high-entropy rare earth oxide fiber, which is prepared by the preparation method described in the first aspect. The chemical formula of the mesoporous high-entropy rare earth oxide fiber is A2B2O7, wherein A is a metallic element, including at least four of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. B is a metallic element, including one or more of zirconium, hafnium, niobium, tantalum, and titanium.

[0013] Furthermore, the mesoporous high-entropy rare earth oxide fiber has a single-phase fluorite structure with a diameter of 40-100 nm and a mesopore size of 6-18 nm.

[0014] Thirdly, embodiments of the present invention provide an application of mesoporous high-entropy rare earth oxide fibers. The application of the mesoporous high-entropy rare earth oxide fibers in the low-temperature sintering preparation of rare earth ceramics includes the following steps: Mesoporous high-entropy rare earth oxides are loaded into a graphite mold, which is then placed in a discharge plasma sintering furnace for sintering under vacuum conditions. The sintering pressure is 40-60 MPa, the sintering temperature is controlled at 1200-1300℃, the heating rate is 50-200℃ / min, and the holding time is 1-10 minutes. After sintering, the high-entropy rare earth oxide ceramic material is obtained by polishing.

[0015] Furthermore, the relative density of the high-entropy rare-earth oxide ceramic material reaches 97.5%-99%, and the fracture toughness is 2.3-2.5 MPa·m. 1 / 2 Its Vickers hardness is 11.2-11.8 GPa.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention adjusts PEO- b - The interaction between PS template agent, PVP and metal salt, in which PEO- b PS spontaneously aggregates into spherical micelles, PVP coordinates with metal salts and surrounds the micelles, and an electric field is applied to them, so that the three can synergistically assemble in the electrospinning beam, achieving precise control of the number of micelles and metals at the molecular level, and controllable pore size. Further control of the calcination process removes the spherical micelles and PVP step by step, realizing the precise construction of one-dimensional high-entropy oxide fibers. The resulting mesoporous high-entropy rare earth oxide fibers have uniform diameter and regular mesopore distribution.

[0017] (2) The mesoporous high-entropy rare earth oxide fiber obtained by the present invention has a single-phase fluorite structure with a diameter of 40-100 nm and a mesopore size of 6-18 nm. Its chemical formula is A2B2O7, where A is a metallic element, including at least four of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium; B is a metallic element, including one or more of zirconium, hafnium, niobium, tantalum and titanium. That is, the fiber of the present application is an inorganic compound solid solution formed by five or more main elements sharing one or more Wyckoff sites in equal atomic proportions. The ceramic made from the fiber utilizes the significant high-entropy effect to stabilize the single crystal structure. Combined with the lattice distortion effect, slow diffusion effect and "cocktail" effect, it can break through the performance limitations of traditional ceramics.

[0018] (3) In the process of preparing high-entropy rare earth oxide ceramics by spark plasma sintering, the mesoporous fiber structure of this invention is broken under the action of temperature and pressure, and an in-situ sintering driving force is generated to promote sintering, thereby improving the sintering activity of the ceramic. The sintering temperature is reduced by 25-30% compared with the traditional method (i.e., reduced by 300-400℃). Such a low temperature effectively inhibits abnormal grain growth and improves the mechanical properties of the ceramic material (relative density reaches 97.5%-99%, fracture toughness is 2.3-2.5 MPa·m). 1 / 2 With a Vickers hardness of 11.2-11.8 GPa, this preparation process is highly controllable and significantly reduces energy consumption, making it suitable for large-scale preparation. It has broad application prospects in aerospace thermal protection, solid oxide fuel cells and other fields. Attached Figure Description

[0019] Figure 1The infrared spectra are those of the sample with and without metal in Example 1.

[0020] Figure 2 PEO- in Example 1 b - Zeta potential plots of PS micelles, metal / PVP, and micelles / metal / PVP.

[0021] Figure 3 The image shows the XRD pattern of the hexa-membered mesoporous high-entropy rare earth oxide fiber obtained in Example 1.

[0022] Figure 4 This is a TEM image of the hexa-membered mesoporous high-entropy rare earth oxide fiber obtained in Example 1.

[0023] Figure 5 The images shown are HAADF-STEM images and corresponding EDSmaps images of the hexa-membered mesoporous high-entropy rare earth oxide fibers obtained in Example 1.

[0024] Figure 6 The mechanical properties of the hexa-, heptadecimal, and twentieth-eighth ...

[0025] Figure 7 The image shows the XRD pattern of the heptaphylactic mesoporous high-entropy rare earth oxide fiber obtained in Example 2.

[0026] Figure 8 This is a TEM image of the heptaphylactic mesoporous high-entropy rare earth oxide fiber obtained in Example 2.

[0027] Figure 9 The images show the HAADF-STEM images and corresponding EDS maps of the seventeen-membered mesoporous high-entropy rare earth oxide fibers obtained in Example 2.

[0028] Figure 10 The image shows the XRD pattern of the 21-membered mesoporous high-entropy rare earth oxide fiber obtained in Example 3.

[0029] Figure 11 This is a TEM image of the 21-membered mesoporous high-entropy rare earth oxide fiber obtained in Example 3.

[0030] Figure 12 The images shown are HAADF-STEM images and corresponding EDS maps of the 21-membered mesoporous high-entropy rare earth oxide fibers obtained in Example 3.

[0031] Figure 13 This is a TEM image of the hexa-membered mesoporous high-entropy rare earth oxide fiber obtained in Example 4.

[0032] Figure 14 This is a TEM image of the hexa-membered non-mesoporous high-entropy rare earth oxide fiber obtained in Example 5. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example 1 A method for preparing a hexa-membered mesoporous high-entropy rare earth oxide fiber ((LaNdSmEuGd)2Zr2O7, mHEONF-6) includes the following steps: (1) Mix 9 mL of dimethylacetamide with 1 mL of ethanol, and add 100 mg of PEO- with a molecular weight of 23056 g / mol and a polydispersity index of 1.06. b -PS, stir to completely dissolve, and obtain a micelle solution; (2) Combine 56 mg La(NO3)3·6H2O, 57 mg Nd(NO3)3·6H2O, 58 mg Sm(NO3)3·6H2O, 58 mg Eu(NO3)3·6H2O, 58 mg Gd(NO3)3·6H2O and 314 mg C 20 H 28 O8Zr was added to the micelle solution obtained in step (1) and stirred for 2 hours to dissolve; (3) Add 0.74 g of PVP with a molecular weight of 130w to the solution obtained in step (2), adjust the pH value of the system to between 4 and 8, and stir magnetically for 6 hours to obtain a clear and transparent spinning solution with a certain viscosity. (4) Transfer the spinning solution obtained in step (3) into a 10 mL syringe, apply a high voltage of 17.5 kV (DC) between the syringe needle and the roller coated with silicone paper, receive at a distance of 20 cm, spin at a speed of 0.6 mL / h, and carry out electrospinning at 35°C and 25% humidity. Then, heat-treat the obtained composite fiber membrane at 80°C for 24 h to completely remove the solvent. (5) The composite fiber obtained in step (4) is first heated to 350°C in air at 2°C / min and held for 2 hours to remove PEO- b -PS template, then further added at the same heating rate to 600℃ to remove PVP, and finally the temperature is raised to 800℃ to completely burn off the PVP framework and complete the high entropy of the metal. After cooling, hexa-membered mesoporous high entropy rare earth oxide fiber ((LaNdSmEuGd)2Zr2O7, mHEONF-6) is obtained.

[0035] In the preparation of the spinning solution, the representative carbonyl bond of PVP in the metal-free solution system is located at 1658 cm⁻¹.-1 In contrast, the carbonyl bonds in the solution system with added metal showed a significant blue shift, indicating that the metal coordinated with the carbonyl groups of PVP. Furthermore, the zeta potential of the micelles was positive, and the potential of the PVP / metal was even more positive. However, the potential decreased after the two were mixed, proving that there is an interaction between the micelles and the PVP / metal. It is this dual interaction that ensures that the micelles are not destroyed during electrospinning, thus maintaining a good mesoporous morphology.

[0036] XRD analysis confirmed that the obtained hexa-membered mesoporous high-entropy rare earth oxide fibers exhibited a single-phase fluorite structure without phase separation. Figure 3 As shown, compared with the standard card (01-071-2363) of fluorite phase La2Zr2O7, the peak shape of the hexa-membered mesoporous high-entropy rare earth oxide fiber is completely consistent, with only a slight shift in peak position. This is due to the small radius of the incorporated metal, resulting in a lattice contraction effect. TEM observation revealed a mesoporous fiber structure with a pore size of approximately 10 nm. Figure 4 As shown, and all elements are mixed uniformly, as Figure 5 As shown.

[0037] The above-mentioned hexa-membered mesoporous high-entropy rare earth oxide fibers are used to prepare ceramics by low-temperature sintering, including the following steps: The obtained hexa-membered mesoporous high-entropy rare earth oxide fibers were loaded into a graphite mold coated with graphite paper and initially compacted at 40 MPa. Then, they were placed in a discharge plasma sintering furnace and heated to 1300℃ at a heating rate of 100℃ / min. The uniaxial pressure was gradually increased to 50 MPa and held at that temperature for 5 min before being naturally cooled to room temperature. After cooling, the ceramic block was removed, the surface carbon paper was removed, and the ceramic was polished with sandpaper of different grits to finally obtain a dense and smooth hexa-membered high-entropy rare earth oxide ceramic.

[0038] The density of the hexavalent high-entropy rare earth oxide ceramic, determined using Archimedes' displacement method, was 6.39 g / cm³. 3 With a relative density of 97.5%, this ceramic exhibits a fracture toughness of 2.5 MPa·m. 1 / 2 Its Vickers hardness is 11.2 GPa, such as Figure 4 As shown.

[0039] Example 2 This embodiment is basically the same as Example 1, except that the amount of metal added in step (2) is adjusted to 36 mg La(NO3)3·6H2O, 36 mg Nd(NO3)3·6H2O, 36 mg Sm(NO3)3·6H2O, 36 mg Eu(NO3)3·6H2O, 36 mg Gd(NO3)3·6H2O, 36 mg Ce(NO3)3·6H2O, 36 mg Pr(NO3)3·6H2O, 36 mg Dy(NO3)3·5H2O, 36 mg Ho(NO3)3·5H2O, 36 mg Er(NO3)3·5H2O, 36 mg Tm(NO3)3·5H2O, 36 mg Yb(NO3)3·6H2O, 38 mg Lu(NO3)3·6H2O, 36 mg Tb(NO3)3·5H2O, and 14 mg Sc(NO3)3·6H2O, 32 mg Y(NO3)3·6H2O, and 314 mg C 20 H 28 O8Zr. Finally, a seventeen-membered mesoporous high-entropy rare earth oxide fiber ((LaNdSmEuGdCePrDyYbLuErTbTmHoYSc)2Zr2O7) was obtained. XRD analysis confirmed that the fiber exhibits a single-phase fluorite structure without phase separation, such as... Figure 7 As shown. The mesoporous fiber structure was observed by TEM, as follows. Figure 8 As shown. And all elements are mixed evenly, as... Figure 9 As shown.

[0040] The low-temperature sintering process for preparing ceramics in this embodiment is basically the same as that in Example 1, and a seventeen-element high-entropy rare earth oxide ceramic is obtained.

[0041] The density of the seventeen-element high-entropy rare earth oxide ceramic was determined to be 6.45 g / cm³ using the Archimedes displacement method. 3 With a relative density of 98.5%, this ceramic exhibits a fracture toughness of 2.25 MPa·m. 1 / 2 Its Vickers hardness is 11.8 GPa, such as Figure 4 As shown.

[0042] Example 3 This embodiment is basically the same as Example 2, except that 314 mg of C is added. 20 H 28 O8Zr was adjusted to 62 mgC. 20 H 28O8Zr, 74 mg Hf(acac)4, 52 mg Nb(OCH(CH3)2)5, 42 mg Ta(OCH(CH3)2)5, and 34 mg Ti(OCH2CH2CH2CH3)4 were used to obtain a 21-membered mesoporous high-entropy rare earth oxide fiber ((LaNdSmEuGdCePrDyYbLuErTbTmHoYSc)2(ZrHfTaNbTiO)2O7). XRD analysis confirmed that the fiber exhibits a single-phase fluorite structure without phase separation. Figure 10 As shown. The mesoporous fiber structure was observed by TEM, as follows. Figure 11 As shown, and all elements are mixed uniformly, as Figure 12 As shown.

[0043] The low-temperature sintering process for preparing ceramics in this embodiment is basically the same as that in Example 1, and 21-element high-entropy rare earth oxide ceramics are obtained.

[0044] The density of the 21-element high-entropy rare earth oxide ceramic, determined using Archimedes' displacement method, was 6.49 g / cm³. 3 With a relative density of 99.0%, this ceramic exhibits a fracture toughness of 2.37 MPa·m. 1 / 2 Its Vickers hardness is 11.4 GPa, such as Figure 4 As shown.

[0045] Example 4 This embodiment is basically the same as embodiment 2, except that PEO- is added. b - The molecular weight of PS was adjusted to 35680, and the polydispersity index was 1.15.

[0046] The aperture size measured by TEM is approximately 15 nm, such as Figure 13 As shown, the pore size is larger than that of Example 2, which is due to the pore-forming agent PEO- b - The larger molecular weight of PS naturally results in a larger pore size, indicating that our method can control the size of the mesopores by adjusting the molecular weight.

[0047] Example 5 This embodiment is basically the same as embodiment 2, except that PEO- is not added. b -PS.

[0048] No clearly ordered mesoporous structure was observed in the TEM images, such as Figure 14 As shown, this further demonstrates PEO- b - The pore-forming function of PS.

[0049] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing mesoporous high-entropy rare earth oxide fibers, characterized in that, Includes the following steps: (1) Prepare a mixed solution by mixing dimethylacetamide and anhydrous ethanol, and add polyethylene oxide-polystyrene block copolymer PEO- b -PS, magnetic stirring to completely dissolve it, to obtain a micelle solution; (2) Add the required metal salt to the PEO- obtained in step (1). b - A clear and transparent solution was obtained by stirring in a PS micelle solution; (3) Add polyvinylpyrrolidone (PVP) to the solution obtained in step (2), adjust the pH of the system to between 2.5 and 6.5, and stir magnetically for 4-12 hours to obtain a clear, transparent, and viscous spinning solution. (4) The spinning solution obtained in step (3) is electrospun, collected and dried with silicone paper to obtain composite fiber; (5) The fiber obtained in step (4) is calcined in segments in an air atmosphere to obtain mesoporous high-entropy rare earth oxide fiber.

2. The method for preparing mesoporous high-entropy rare earth oxide fibers according to claim 1, characterized in that, In step (1), the volume ratio of dimethylacetamide to anhydrous ethanol is 5:1-9:1, and the PEO- b - The concentration of the PS micelle solution was controlled at 5-10 mg / mL.

3. The method for preparing mesoporous high-entropy rare earth oxide fibers according to claim 1, characterized in that, In step (2), the PEO- b- The molecular weight of PS is 20,000-40,000 g / mol, and the polydispersity index is 1.06-1.

15. The metal salt and PEO- b- The quality ratio of PS is 4:1-6:1; The metal salt is selected from at least four of the following: lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, lutetium nitrate, scandium nitrate, and yttrium nitrate, to form the A-site of the mesoporous high-entropy rare earth oxide fiber; The metal salt is one or more of zirconium acetylacetonate, hafnium acetylacetonate, niobium isopropoxide, tantalum isopropoxide, and tetrabutyl titanate, forming the B site of the mesoporous high-entropy rare earth oxide fiber.

4. The method for preparing mesoporous high-entropy rare earth oxide fibers according to claim 1, characterized in that, In step (3), the molecular weight of the polyvinylpyrrolidone is 108-165w, and its mass fraction relative to the whole system is 6-10%.

5. The method for preparing mesoporous high-entropy rare earth oxide fibers according to claim 1, characterized in that, In step (4), the electrospinning process has the following spinning parameters: voltage of 17-21 kV, receiving distance of 15-25 cm, spinning speed of 0.5-0.8 mL / h, temperature of 25-35℃, and relative humidity not exceeding 25%.

6. The method for preparing mesoporous high-entropy rare earth oxide fibers according to claim 1, characterized in that, In step (5), the air calcination process should be divided into three stages. The first stage involves raising the temperature to 320-350℃ at a rate not exceeding 2℃ / min and maintaining it for 1-2 hours to remove the template agent PEO- b -PS, the second stage continues to heat to 500-600℃ at the same heating rate to remove PVP and complete metal oxidation, the third stage heats to 600-1000℃ at 5-10℃ / min to obtain mesoporous high-entropy rare earth oxide fibers.

7. A mesoporous high-entropy rare earth oxide fiber, characterized in that, The mesoporous high-entropy rare earth oxide fiber is prepared by any one of claims 1-6, and the chemical formula of the fiber is A2B2O7, wherein A is a metallic element, including at least four of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. B is a metallic element, including one or more of zirconium, hafnium, niobium, tantalum, and titanium.

8. The mesoporous high-entropy rare earth oxide fiber according to claim 7, characterized in that, The mesoporous high-entropy rare earth oxide fiber has a single-phase fluorite structure with a diameter of 40-100 nm and a mesopore size of 6-18 nm.

9. An application of a mesoporous high-entropy rare earth oxide fiber, characterized in that, The mesoporous high-entropy rare earth oxide fiber is used in the low-temperature sintering preparation of rare earth ceramics, including the following steps: Mesoporous high-entropy rare earth oxides are loaded into a graphite mold, which is then placed in a discharge plasma sintering furnace for sintering under vacuum conditions. The sintering pressure is 40-60 MPa, the sintering temperature is controlled at 1200-1300℃, the heating rate is 50-200℃ / min, and the holding time is 1-10 minutes. After sintering, the high-entropy rare earth oxide ceramic material is obtained by polishing.

10. The application of the mesoporous high-entropy rare earth oxide according to claim 9, characterized in that, The high-entropy rare earth oxide ceramic material has a relative density of 97.5%-99% and a fracture toughness of 2.3-2.5 MPa·m. 1 / 2 Its Vickers hardness is 11.2-11.8 GPa.

Images