High-entropy rare earth zirconate superfine nano ceramic powder and preparation method thereof

Abstract

The invention discloses high-entropy rare earth zirconate superfine nano ceramic powder and a preparation method thereof, the molecular formula of the nano ceramic powder is (xREy) 2Zr2O7, RE is 5-6 of Eu, Gd, Dy, Ho, Sm, Y, Yb, Er, Nd and La, the value of x is 5 or 6, and the value range of y is 5%-35%; the preparation method comprises the following steps: dissolving ZrOCl2. 8H2O with the molar content percentage of 50% and 5-6 RE nitrate hydrate powder with the molar content percentage of 2.5%-17.5% in deionized water, then adding urea, stirring in a water bath, and carrying out suction filtration and washing while the solution is hot to obtain precursor powder; and then calcining and uniformly grinding to obtain the high-entropy rare earth zirconate superfine nano ceramic powder. The average particle size of the prepared high-entropy rare earth zirconate superfine nano ceramic powder is only 4-50 nm, the element distribution is uniform, the component adjustment space is large, and the high-entropy rare earth zirconate superfine nano ceramic powder does not contain impurities and the like. The preparation method has the advantages of low synthesis temperature, simple equipment, simple and controllable process, low industrialization cost and the like.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a high-entropy rare earth zirconate ultrafine nano-ceramic powder and its preparation method. Background Technology

[0002] With the continuous development and advancement of aero-engine and gas turbine technologies, the high-temperature extreme environments and performance optimization requirements of their applications place higher demands on the operating temperature, thermal insulation performance, and service life of thermal barrier coating materials. Yttrium-stabilized zirconia ceramic (YSZ) thermal barrier coatings suffer from high thermal conductivity at high temperatures and are prone to phase transformation aging, making it difficult to exceed 1300℃ in service temperature. High-entropy rare-earth zirconate ceramics (A₂Zr₂O₇), by introducing multiple principal elements at the A-site to form complex crystal structures such as pyrochlore and defective fluorite, exhibit high thermal stability up to 1600℃ and a service life below 1.5 W·m⁻¹. -1 ·K -1 With its excellent properties such as low thermal conductivity, it is a new type of thermal barrier coating material with application potential.

[0003] Studies have shown that increasing the differences in atomic mass, ionic radius, and lattice distortion among the main elements through material composition design can enhance phonon scattering, thereby reducing the thermal conductivity of high-entropy zirconate ceramics. Furthermore, forming a nanocrystalline structure to increase grain boundary density can enhance interfacial phonon scattering, further reducing thermal conductivity. The preparation of ultrafine nanoceramic powders is a prerequisite for obtaining nanocrystalline high-entropy zirconate ceramics. Therefore, developing high-entropy zirconate ultrafine nanoceramic powder preparation technology is of great significance for optimizing the microstructure and thermal properties of materials.

[0004] Chinese Patent Publication No. CN117486610A discloses a high-entropy rare-earth silicate ceramic nanopowder and its preparation method. The method involves dissolving rare-earth oxide powder in an acid solution to prepare a rare-earth salt solution, mixing it with a sodium silicate solution, adding ammonia for chemical co-precipitation, and then allowing it to stand, age, filter, and dry to obtain a precursor powder. The precursor powder is then calcined at 1100℃~1200℃ to obtain high-entropy rare-earth silicate ceramic nanopowder with an average particle size of 100nm~200nm.

[0005] Chinese patent CN110563035A discloses a rare earth zirconate nanoparticle and its preparation method. The method involves mixing rare earth oxides, zirconium oxide, molten salt, and anhydrous ethanol to obtain a mixture, which is then calcined at high temperature to obtain rare earth zirconate ceramic nanoparticles with an average particle size of 50 nm to 200 nm.

[0006] Published paper "Guo D, Zhou F, Xu B, Wang Y, Wang Y, Synthesis and characterization of high-entropy (La 0.2 Nd 0.2 Sm 0.2 Gd 0.2 Yb 0.2 )2(Zr 0.75 Ce 0.25 "2O7 nanopowders, Ceram. Int., 48(2022) 32532-32535." reported a method for preparing high-entropy (La) nanopowders. 0.2 Nd 0.2 Sm 0.2 Gd 0.2 Yb 0.2 )2(Zr 0.75 Ce 0.25 A method for preparing 2O7 nanoparticles is described. The method uses nitrate hexahydrate as raw material, citric acid as complexing agent, and deionized water as solvent. After mixing them to form a homogeneous solution, ethylene glycol is added to adjust the pH to 2. Then, the solution is heated in a water bath at 80°C with continuous stirring until the excess water evaporates to obtain a wet gel. After drying the wet gel, it is calcined at 850°C for 3 hours to obtain nanoparticles with an average particle size of about 15 nm.

[0007] In summary, the average grain size of reported rare-earth zirconate ceramic nanopowders generally ranges from 15 nm to 200 nm. However, research indicates that only when the average grain size is less than 50 nm can the grain boundary scattering effect be fully utilized, further reducing the phonon mean free path and thus significantly lowering the material's thermal conductivity. The ceramic powders prepared by ammonia co-precipitation and molten salt methods have average particle sizes between 50 nm and 200 nm, failing to fully leverage the phonon scattering enhancement effect of nanocrystals. While the ceramic powders prepared by the sol-gel method have an average particle size of only 15 nm, the process is complex and requires strict control of process conditions. Therefore, it is essential to develop a novel method for preparing high-entropy rare-earth zirconate ultrafine nanoceramic powders that is easy to equip, has a simple and controllable process, and low industrialization costs, to obtain high-entropy rare-earth zirconate ultrafine nanoceramic powders with particle sizes less than 50 nm, uniform elemental distribution, high purity, and large compositional space. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the present invention aims to provide a high-entropy rare earth zirconate ultrafine nano-ceramic powder and its preparation method, wherein the average particle size of the obtained high-entropy rare earth zirconate ultrafine nano-ceramic powder is only 4nm to 50nm.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A high-entropy rare-earth zirconate ultrafine nano-ceramic powder, the molecular formula of which is (xRE) y )2Zr2O7, where RE is 5 to 6 of Eu, Gd, Dy, Ho, Sm, Y, Yb, Er, Nd and La, x takes the value of 5 or 6, and y takes the value of 5% to 35%.

[0011] Preferably, the average particle size is 4 nm to 50 nm.

[0012] A method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder includes the following steps:

[0013] Step 1: Dissolve 5-6 powders from the following sources (ZrOCl2·8H2O, Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, Dy(NO3)3·6H2O, Ho(NO3)3·5H2O, Sm(NO3)3·6H2O, Nd(NO3)3·6H2O, Er(NO3)3·6H2O, Y(NO3)3·6H2O, Yb(NO3)3·5H2O, and La(NO3)3·6H2O) in deionized water to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L. The molar percentage of each of the 5-6 nitrate hydrate powders is 2.5% to 17.5%.

[0014] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is (20-40):1. After mixing, stir the solution at room temperature for 2-3 hours and then continue stirring in a water bath at 90-100°C for 3-4 hours. After hot filtration and washing, dry at 80-120°C for 12-24 hours to obtain the precursor powder.

[0015] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, heat it to 800℃~1200℃ at a rate of 2.5℃ / min~10℃ / min and hold it at that temperature, then cool it down to 800℃ at a rate of 10℃ / min and cool it with the furnace. Grind the calcined powder evenly to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0016] Preferably, the chemical purity of the raw material powder is greater than 99.0%.

[0017] Preferably, the washing method after hot filtration in step 2 is to first wash with deionized water 5 times, and then wash with anhydrous ethanol 3 times to remove byproducts in the solution.

[0018] Preferably, the calcination and heat preservation time of the powder in step 3 is 2h to 4h.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1) Urea hydrolyzes under heating conditions (usually above 70℃) to produce ammonia and carbon dioxide. The generated ammonia gradually increases the pH of the solution, which is conducive to the simultaneous and uniform precipitation of multiple metal ions as hydroxide or carbonate precursors. This slow and uniform precipitation process avoids rapid nucleation and aggregation caused by local supersaturation, thus forming finer particles. The carbonyl groups in urea can also form weak complexes with metal ions, slowing down the precipitation rate and further refining the particles.

[0021] 2) The high-entropy rare earth zirconate nanoceramic powder provided by this invention has an average grain size of 4nm to 50nm, uniform element distribution and no impurity phase.

[0022] 3) This invention uses the urea co-precipitation method to prepare high-entropy nano-ceramic powder, which has the advantages of simple equipment, simple and controllable process, and low industrialization cost. Attached Figure Description

[0023] Figure 1 This is the XRD pattern of the high-entropy rare-earth zirconate ultrafine nano-ceramic powder obtained in Example 7 of the present invention;

[0024] Figure 2 This is a TEM image of the high-entropy rare-earth zirconate ceramic ultrafine nanoparticles obtained in Example 7 of the present invention;

[0025] Figure 3 This is a particle size distribution diagram of the high-entropy rare-earth zirconate ceramic ultrafine nanoparticles obtained in Example 7 of the present invention. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments, but this is not intended to limit the present invention.

[0027] Example 1

[0028] This invention provides a method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder, specifically including the following steps;

[0029] Step 1: The chemical purity of the raw material powders must be greater than 99.0%. Dissolve 50% ZrOCl2·8H2O, 2.5% Eu(NO3)3·6H2O, 10% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 10% Ho(NO3)3·5H2O, and 17.5% Sm(NO3)3·6H2O in deionized water according to the molar percentage to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0030] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is 20:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 90°C water bath for 3 hours. Then, filter and wash while hot, and dry at 80°C for 24 hours to obtain the precursor powder.

[0031] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, heat it to 800℃ at a rate of 2.5℃ / min and hold it for 2 hours, then cool it with the furnace, and then cool it down to 800℃ at a rate of 10℃ / min and then cool it with the furnace. Grind the calcined powder evenly to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0032] The nano-ceramic powder prepared in this embodiment has the molecular formula (Eu) 0.05 Gd 0.2 Dy 0.2 Ho 0.2 Sm 0.35 )2Zr2O7.

[0033] Example 2

[0034] Step 1: Dissolve 50% ZrOCl2·8H2O, 17.5% Eu(NO3)3·6H2O, 10% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 10% Ho(NO3)3·5H2O, and 2.5% Sm(NO3)3·6H2O powders in deionized water according to their molar percentages to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0035] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is 30:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 93°C water bath for 3 hours. Then filter while hot, wash with deionized water 5 times, and then wash with anhydrous ethanol 3 times to remove byproducts in the solution. After washing, dry at 90°C for 20 hours to obtain precursor powder.

[0036] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, heat it to 1000℃ at a rate of 2.5℃ / min and hold it for 3 hours, then cool it to 800℃ at a rate of 10℃ / min and cool it with the furnace. Grind the calcined powder evenly to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0037] The nano-ceramic powder prepared in this embodiment has the molecular formula (Eu) 0.35 Gd 0.2 Dy 0.2 Ho 0.2 Sm0.05 )2Zr2O7.

[0038] Example 3

[0039] Step 1: Dissolve 50% ZrOCl2·8H2O and 17.5% La(NO3)3·6H2O, 2.5% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 17.5% Ho(NO3)3·5H2O, and 2.5% Nd(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0040] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is 40:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 93°C water bath for 3 hours. Then, filter and wash while hot, and dry at 100°C for 18 hours to obtain the precursor powder.

[0041] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1200℃ at a heating rate of 4℃ / min and hold for 4h, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0042] The nano-ceramic powder prepared in this embodiment has the molecular formula (La). 0.35 Gd 0.05 Dy 0.2 Ho 0.35 Nd 0.05 )2Zr2O7.

[0043] Example 4

[0044] Step 1: Dissolve 50% ZrOCl2·8H2O powder and 2.5% La(NO3)3·6H2O, 17.5% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 2.5% Ho(NO3)3·5H2O, and 17.5% Nd(NO3)3·6H2O powder in deionized water according to the molar percentage to obtain 200 mL of inorganic salt solution with a concentration of 0.1 mol / L.

[0045] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is 25:1. After mixing, stir the solution at room temperature for 3 hours and then continue stirring in a 93°C water bath for 4 hours. Then, filter and wash while hot, and dry at 120°C for 12 hours to obtain the precursor powder.

[0046] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 900℃ at a heating rate of 5℃ / min and hold for 2 hours, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0047] The nano-ceramic powder prepared in this embodiment has the molecular formula (La). 0.05 Gd 0.35 Dy 0.2 Ho 0.05 Nd 0.35 )2Zr2O7.

[0048] Example 5

[0049] Step 1: Dissolve 50% ZrOCl2·8H2O and 2.5% Yb(NO3)3·5H2O, 17.5% Y(NO3)3·6H2O, 17.5% Dy(NO3)3·6H2O, 2.5% Er(NO3)3·6H2O, and 10% Nd(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0050] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is 35:1. After mixing, stir the solution at room temperature for 3 hours and then continue stirring in a 94°C water bath for 4 hours. Then, filter and wash while hot, and dry at 110°C for 16 hours to obtain the precursor powder.

[0051] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1100℃ at a heating rate of 5℃ / min and hold for 3h, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0052] The nano-ceramic powder prepared in this embodiment has the molecular formula (Yb 0.05 Y 0.35 Dy 0.35 Er 0.05 Nd 0.2 )2Zr2O7.

[0053] Example 6

[0054] Step 1: Dissolve 50% ZrOCl2·8H2O and 17.5% Yb(NO3)3·5H2O, 2.5% Y(NO3)3·6H2O, 2.5% Dy(NO3)3·6H2O, 17.5% Er(NO3)3·6H2O, and 10% Nd(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0055] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal ions is 30:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 95°C water bath for 3 hours. Then, filter and wash while hot, and dry at 90°C for 22 hours to obtain the precursor powder.

[0056] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1100℃ at a heating rate of 6℃ / min and hold for 4h, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0057] The nano-ceramic powder prepared in this embodiment has the molecular formula (Yb 0.35 Y 0.05 Dy 0.05 Er 0.35 Nd 0.2 )2Zr2O7.

[0058] Example 7

[0059] Step 1: Dissolve 50% ZrOCl2·8H2O and 10% Eu(NO3)3·6H2O, 10% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 10% Ho(NO3)3·5H2O, and 10% Nd(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of inorganic salt solution with a concentration of 0.1 mol / L.

[0060] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal ions is 20:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 90°C water bath for 3 hours. Then, filter and wash while hot, and dry at 100°C for 18 hours to obtain the precursor powder.

[0061] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1000℃ at a heating rate of 2.5℃ / min and hold for 2 hours, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0062] The nano-ceramic powder prepared in this embodiment has the molecular formula (Eu) 0.2 Gd 0.2 Dy 0.2 Ho 0.2 Nd 0.2 )2Zr2O7.

[0063] Example 8

[0064] Step 1: Dissolve 50% ZrOCl2·8H2O and 5% Eu(NO3)3·6H2O, 10% Gd(NO3)3·6H2O, 10% Dy(NO3)3·6H2O, 10% Ho(NO3)3·5H2O, 10% Nd(NO3)3·6H2O, and 5% Sm(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of inorganic salt solution with a concentration of 0.1 mol / L.

[0065] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal ions is 40:1. After mixing, stir the solution at room temperature for 3 hours and then continue stirring in a 97°C water bath for 3 hours. Then, filter and wash while hot, and dry at 80°C for 24 hours to obtain the precursor powder.

[0066] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1200℃ at a heating rate of 7℃ / min and hold for 3h, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0067] The nano-ceramic powder prepared in this embodiment has the molecular formula (Eu) 0.1 Gd 0.2 Dy 0.2 Ho 0.2 Nd 0.2 Sm 0.1 )2Zr2O7.

[0068] Example 9

[0069] Step 1: Dissolve 50% ZrOCl2·8H2O and 7.5% La(NO3)3·6H2O, 7.5% Yb(NO3)3·5H2O, 10% Dy(NO3)3·6H2O, 10% Ho(NO3)3·5H2O, 10% Nd(NO3)3·6H2O, and 5% Sm(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of inorganic salt solution with a concentration of 0.1 mol / L.

[0070] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal ions is 30:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 99°C water bath for 4 hours. Then, filter and wash while hot, and dry at 90°C for 21 hours to obtain the precursor powder.

[0071] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 1100℃ at a heating rate of 9℃ / min and hold for 2 hours, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0072] The nano-ceramic powder prepared in this embodiment has the molecular formula (La). 0.15 Yb 0.15 Dy 0.2 Ho 0.2 Nd 0.2 Sm 0.1 )2Zr2O7.

[0073] Example 10

[0074] Step 1: Dissolve 50% ZrOCl2·8H2O and 2.5% Y(NO3)3·6H2O, 7.5% Yb(NO3)3·5H2O, 10% Er(NO3)3·6H2O, 17.5% Ho(NO3)3·5H2O, 2.5% Nd(NO3)3·5H2O, and 10% Sm(NO3)3·6H2O powders in deionized water according to the molar percentage to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L.

[0075] Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal ions is 25:1. After mixing, stir the solution at room temperature for 2 hours and then continue stirring in a 100°C water bath for 3 hours. Then, filter and wash while hot, and dry at 120°C for 13 hours to obtain the precursor powder.

[0076] Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, raise the temperature to 900℃ at a heating rate of 10℃ / min and hold for 2 hours, then lower the temperature to 800℃ at a rate of 10℃ / min and cool with the furnace to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

[0077] The nano-ceramic powder prepared in this embodiment has the molecular formula (Y). 0.05 Yb 0.15 Er 0.2 Ho 0.35 Nd 0.05 Sm 0.2 )2Zr2O7.

[0078] Experimental analysis showed that all embodiments yielded high-entropy rare-earth zirconate nanoparticles with a single-phase fluorite structure and uniform elemental distribution. Among them, the powder obtained after calcination at 800℃ had the smallest particle size, ranging from 4 nm to 10 nm.

[0079] Figure 1 The XRD pattern of the high-entropy rare earth zirconate ultrafine nano-ceramic powder obtained in Example 7 shows that the material has a fluorite structure and no impurity phase.

[0080] Figure 2 The image shows a TEM image of the high-entropy rare earth zirconate ultrafine nanoceramic powder obtained in Example 7. The results show that the obtained powder has good dispersibility and fine particles.

[0081] Figure 3 The histogram of particle size distribution of the high-entropy rare earth zirconate ultrafine nano-ceramic powder obtained in Example 7 shows that the average particle size of the ceramic powder is only 18.91 ± 0.38 nm.

[0082] In summary, this invention has obtained a high-entropy rare earth zirconate ultrafine nano-ceramic powder and its preparation method through component design and preparation process optimization. The preparation method is simple and easy to use, and the resulting powder has a particle size between 4nm and 50nm, with uniform element distribution and no impurities.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-entropy rare-earth zirconate ultrafine nano-ceramic powder, characterized in that: The molecular formula of the nano-ceramic powder is (xRE) y )2Zr2O7, where RE is 5 to 6 of Eu, Gd, Dy, Ho, Sm, Y, Yb, Er, Nd and La, x takes the value of 5 or 6, and y takes the value of 5% to 35%.

2. The high-entropy rare-earth zirconate ultrafine nano-ceramic powder according to claim 1, characterized in that, The average particle size is 4nm to 50nm.

3. A method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder as described in claims 1-2, characterized in that, Includes the following steps: Step 1: Dissolve 5-6 powders from the following sources (ZrOCl2·8H2O, Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, Dy(NO3)3·6H2O, Ho(NO3)3·5H2O, Sm(NO3)3·6H2O, Nd(NO3)3·6H2O, Er(NO3)3·6H2O, Y(NO3)3·6H2O, Yb(NO3)3·5H2O, and La(NO3)3·6H2O) in deionized water to obtain 200 mL of an inorganic salt solution with a concentration of 0.1 mol / L. The molar percentage of each of the 5-6 nitrate hydrate powders is 2.5% to 17.5%. Step 2: Add urea to the inorganic salt solution in Step 1. The molar ratio of urea to total metal cations is (20-40):

1. After mixing, stir the solution at room temperature for 2-3 hours and then continue stirring in a water bath at 90-100°C for 3-4 hours. Then, filter and wash while hot, and then dry at 80-120°C for 12-24 hours to obtain the precursor powder. Step 3: Place the precursor powder obtained in Step 2 into an alumina crucible, place the alumina crucible in a muffle furnace, heat it to 800℃~1200℃ at a rate of 2.5℃ / min~10℃ / min and hold it at that temperature, then cool it down to 800℃ at a rate of 10℃ / min and cool it with the furnace. Grind the calcined powder evenly to obtain high-entropy rare earth zirconate ultrafine nano ceramic powder.

4. The method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder according to claim 3, characterized in that: The chemical purity of the raw material powders is greater than 99.0%.

5. The method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder according to claim 3, characterized in that: The washing method for hot filtration described in step 2 involves washing the solution five times with deionized water and then three times with anhydrous ethanol to remove byproducts.

6. The method for preparing high-entropy rare-earth zirconate ultrafine nano-ceramic powder according to claim 3, characterized in that: In step 3, the calcination and heat preservation time for the powder is 2h to 4h.

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