A high-entropy rare earth silicate ceramic powder and a method of making the same

Abstract

This invention discloses a high-entropy rare-earth silicate ceramic powder and its preparation method. A flocculent precipitate is obtained through in-situ chemical co-precipitation via both forward titration (adding ammonium carbonate solution to a precursor solution) and reverse titration (adding the precursor solution to an ammonium carbonate solution). This precipitate is then repeatedly washed, dried, and calcined at high temperature to prepare a monoclinic high-entropy silicate powder. This invention arbitrarily selects five trivalent lanthanide rare-earth elements with different ionic radii and dissolves them into the high-entropy rare-earth silicate lattice, thereby significantly increasing the configurational entropy and lattice distortion of the sample, enhancing the phase structure stability, and resulting in a resonant frequency temperature coefficient closer to 0 ppm / ℃. The bulk sample of the high-entropy rare-earth silicate ceramic powder, after pressing and sintering, has a relative permittivity of 9.82~10.31, which meets the requirements for microwave dielectric ceramics in millimeter-scale communication.

Description

Technical Field

[0001] This invention relates to the field of ceramic preparation technology, specifically to a high-entropy rare-earth silicate ceramic powder and its preparation method. Background Technology

[0002] Silicate ceramics have attracted much attention in fields such as microwave dielectric ceramics due to their low price, large resource reserves, and low relative permittivity. However, traditional silicate ceramics (such as Mg2SiO4, Zn2SiO4, CaSiO3, etc.) still have the following limitations: (1) Microwave dielectric properties are difficult to control, making it difficult to achieve zero temperature coefficient of resonant frequency; (2) Phase separation or the formation of a second phase is prone to occur, leading to increased dielectric loss; (3) High sintering temperature is required, and in order to meet the density requirements, the sintering temperature of most silicate ceramics is greater than 1300°C. ° C, cannot meet the requirements of low temperature co-firing; (4) Mechanical performance bottleneck, silicate ceramics have high hardness but are brittle and difficult to machine.

[0003] To improve the aforementioned properties, current methods primarily involve optimizing the material system through elemental doping or two-phase composites ((Mg,Ca)₂SiO₄, Mg₂SiO₄-CaTiO₃). While these methods can effectively control the dielectric loss or temperature coefficient of the resonant frequency, they are prone to the precipitation of a second phase, limiting the control over the microwave dielectric properties of the material. For example, using Cu... 2+ Partially replaces Mg in Mg2SiO4 2+ The temperature coefficient of resonant frequency of ceramic materials is only -2ppm / ° C, but the resulting MgSiO3 impurity phase increases dielectric loss. Furthermore, achieving a balance between performance is difficult with the two-phase composite, especially in achieving the desired temperature coefficient of resonant frequency (τ). f ) Introducing τ by adjusting 0 f Conversely, ceramic phases may introduce pores or interface defects, thereby sacrificing quality factor.

[0004] In recent years, high-entropy ceramics have shown breakthrough potential in the field of materials design due to their unique multi-principal element effect. High-entropy ceramics are typically composed of five or more elements in equimolar ratios, exhibiting high configurational entropy (ΔS). mix A temperature coefficient ≥1.5R can suppress elemental segregation, stabilize single-phase structures, and optimize the microstructure of materials through lattice distortion, providing a new path for improving the performance of microwave dielectric ceramics. Studies have shown that the high-entropy strategy has been successfully applied in vanadate, oxide, and phosphate systems; for example, high-entropy rare-earth germanate can reduce the large negative resonant frequency temperature coefficient (-70.4 ppm / ) ° C) Optimize to near 0 (-7.4ppm / °(C) However, high-entropy design for monoclinic rare-earth silicates has not been reported, and the preparation of microwave dielectric ceramic powders is currently mainly based on solid-state methods. Therefore, the feasibility of synthesizing monoclinic high-entropy rare-earth silicate ceramic powders by chemical coprecipitation and the mechanism by which the synthesis process affects the grain size and phase structure of high-entropy silicate ceramic powders still need to be explored.

[0005] Therefore, in order to solve the above problems, this paper proposes a high-entropy rare earth silicate ceramic powder and its preparation method. Summary of the Invention

[0006] This invention provides a method for preparing high-entropy rare-earth silicate ceramic powder. Specifically, it involves introducing five rare-earth elements with different ionic radii to construct a multi-principal solid solution; using a high-entropy strategy to improve the configurational entropy and lattice distortion of the sample, thereby enhancing the stability of the lattice structure; and simultaneously employing a chemical co-precipitation method to effectively suppress phase segregation, improve the compositional uniformity and phase purity of the powder, thereby optimizing the microwave dielectric properties of the ceramic material.

[0007] To achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: a high-entropy rare-earth silicate ceramic powder, characterized in that: the chemical composition of the high-entropy rare-earth silicate ceramic powder includes the following: (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 )2SiO5,(Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 )2SiO5,(Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )2SiO 5。

[0008] Furthermore, the high-entropy rare-earth silicate ceramic powder has a monoclinic structure, with uniform distribution of elements and an average grain size of 167.22~313.41 nm.

[0009] Another object of the present invention is to provide a method for preparing high-entropy rare-earth silicate ceramic powder, characterized by comprising the following steps:

[0010] S1. Weigh out nitrate powder and distilled water in a molar ratio of total rare earth nitrate powder to distilled water of 1:5~7. Dissolve the weighed nitrate powder in distilled water to obtain a metal nitrate solution.

[0011] S2. Measure TEOS, anhydrous ethanol, and distilled water in a volume ratio of 1:1.5~2.5:3.5~4.5. Mix the measured TEOS, anhydrous ethanol, and distilled water and stir until homogeneous to obtain a TEOS hydrolysis solution.

[0012] S3. Weigh out ammonium carbonate powder and distilled water in a molar ratio of ammonium carbonate powder to distilled water of 1:5~7. Dissolve the weighed ammonium carbonate powder in distilled water to obtain a precipitant solution.

[0013] S4. Mix the metal nitrate solution with the TEOS hydrolysis solution to obtain a mixed salt precursor solution;

[0014] S5. Forward titration process: Add ammonium carbonate precipitant dropwise to the precursor solution at a rate of 1~2 mL / min, and adjust the pH value to 7~8 using ammonia and dilute nitric acid. Flocculent precipitate is generated in the mixture. Stir it with a magnetic stirrer for 2~4 hours at a stirring rate of 400~500 r / min. After the mixture is thoroughly stirred, let it stand for 20~24 hours to ensure complete precipitation.

[0015] S6. Reverse titration process: The precursor solution is added dropwise to the precipitant solution at a rate of 1~2 mL / min, and the pH value is adjusted to 7~8 using ammonia and dilute nitric acid. Flocculent precipitate is generated in the mixture. The mixture is stirred with a magnetic stirrer for 2~4 hours at a stirring rate of 400~500 r / min. After the mixture is thoroughly stirred, it is allowed to stand for 20~24 hours to ensure complete precipitation.

[0016] S7. After co-precipitation, remove the supernatant and transfer the suspension to a centrifuge tube. Centrifuge and wash the suspension with distilled water and anhydrous ethanol in sequence, repeating the washing until pH=6~7.

[0017] S8. Pour the cleaned suspension into an evaporating dish and dry it in a drying oven at 90~110℃ for 12~14h to obtain solid powder. Grind and sieve the powder, and then place it in a muffle furnace and heat it to 1200~1400℃ at a rate of 5℃ / min. Hold it at this temperature for 6~8h to obtain high entropy rare earth silicate ceramic powder.

[0018] S9. Weigh 3~3.2g of high-entropy silicate powder and press it into shape in a steel mold with a diameter of 12mm, with a pressure of 100~120MPa;

[0019] S10. The billet is sintered in a muffle furnace at a sintering temperature of 1500~1600℃ for 5~6 hours to obtain high-entropy rare earth silicate (5RE). 0.2 )2SiO5) ceramic bulk.

[0020] Furthermore, in S1, the nitrate powder is a mixture of five powders selected from Sm(NO3)3·6H2O, Yb(NO3)3·5H2O, Tm(NO3)3·6H2O, Dy(NO3)3·6H2O, Er(NO3)3·5H2O, Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, Ho(NO3)3·5H2O, Nd(NO3)3·6H2O, and La(NO3)3·6H2O in a molar ratio of 1:1:1:1:1:1.

[0021] Furthermore, in S1 and S2, the molar ratio of Si to rare earth elements in the TEOS hydrolysis solution and the metal nitrate solution is 11~13:20.

[0022] Furthermore, in S1 and S3, the molar ratio of the ammonium carbonate powder to the metal nitrate solution is 1.5~1.8:1.

[0023] Furthermore, in S8, the grinding and sieving of the solid powder includes the following steps:

[0024] (1) The powder sample was ground using an agate mortar and pestle for 30-50 minutes.

[0025] (2) The ground powder is sieved through a sieve with a mesh size of 300~600.

[0026] The beneficial effects of this invention are:

[0027] This invention uses five rare earth elements with different ionic radii and masses to construct a high-entropy solid solution, which significantly improves the configurational entropy and lattice distortion of the sample, stabilizes the silicate phase structure, and effectively solves the problem of poor stability of traditional monocomponent / multicomponent silicate phases.

[0028] This invention employs a chemical coprecipitation method, comparing two titration methods: forward titration and reverse titration. The reverse titration process achieves simultaneous and uniform coprecipitation of rare earth elements and Si elements, avoiding the introduction of impurities and element loss, suppressing the generation of the second phase, and ensuring that the proportion of each element in the powder is highly consistent with the expected and uniformly distributed.

[0029] This invention employs a reverse titration process to control RE 3+ and Si 4+ The precipitation rate is reduced, effectively inhibiting grain growth, resulting in smaller average grain size (167.22~290.09nm) and improved uniformity;

[0030] The high-entropy rare-earth silicate ceramic powder prepared in this invention, after being pressed and sintered, produces a bulk sample with a relative permittivity of 9.82~10.31, which meets the requirements for millimeter-scale communication ε rThe dielectric constant is adjustable over a wide range, meeting the requirements of <15 and adaptable to the requirements of millimeter-wave devices in different frequency bands. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The XRD patterns of the high-entropy rare-earth silicate ceramic powders prepared in Examples 1-6 of this invention are shown below.

[0033] Figure 2 The images are SEM images of the high-entropy rare-earth silicate ceramic powders prepared in Examples 1-6 of this invention.

[0034] Figure 3 The grain size distribution and average grain size of the high-entropy rare-earth silicate ceramic powders prepared in Examples 1-6 of this invention;

[0035] Figure 4 The images show the EDS spectra of the high-entropy rare-earth silicate ceramic powders prepared in Examples 1-6 of this invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] A high-entropy rare earth silicate (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 The preparation method of 2SiO5 ceramic powder is as follows:

[0039] Step 1, according to (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2To prepare 2SiO5, Sm(NO3)3·6H2O powder, Yb(NO3)3·5H2O powder, Tm(NO3)3·6H2O powder, Dy(NO3)3·6H2O powder, and Er(NO3)3·5H2O powder were weighed out according to their stoichiometric ratios. Then, distilled water was weighed out according to the molar ratio of the total amount of nitrate powder to distilled water of 1:5. The nitrate powder was dissolved in the distilled water and stirred continuously at room temperature for 30 minutes to ensure complete dissolution, thus obtaining a metal nitrate solution.

[0040] Step 2: Weigh TEOS according to the molar ratio of silicon to rare earth elements of 20:12, and then weigh anhydrous ethanol and distilled water according to the volume ratio of TEOS: anhydrous ethanol: distilled water = 1:2:4. Then mix the three liquids and stir continuously at room temperature for 30 minutes to allow TEOS to be fully hydrolyzed, and obtain TEOS hydrolysis solution.

[0041] Step 3: Weigh ammonium carbonate powder according to a molar ratio of ammonium carbonate to rare earth elements of 1.5:1, and weigh distilled water according to a molar ratio of ammonium carbonate powder to distilled water of 1:5. Dissolve the ammonium carbonate powder in the distilled water and stir continuously at room temperature for 30 minutes to ensure complete dissolution, thereby obtaining a precipitant solution.

[0042] Step 4: Mix the metal nitrate solution with the TEOS hydrolysis solution and stir continuously at room temperature for 1 hour to ensure thorough mixing, thereby obtaining a mixed salt solution;

[0043] Step 5: Add the precipitant solution dropwise to the mixed salt solution at a rate of 2 mL / min while stirring. Stir for 2 hours. Adjust the pH of the system to 8 by adding a small amount of ammonia or dilute nitric acid solution to generate a large amount of flocculent matter. After stirring thoroughly, let the mixture stand for 24 hours.

[0044] Step 6: Transfer the mixture to a centrifuge tube, discard the supernatant, and centrifuge and wash with distilled water and anhydrous ethanol in sequence until the pH is 7.0.

[0045] Step 7: Pour the cleaned precipitate into an evaporating dish, dry it in a 110℃ drying oven for 24 hours, grind it in an agate mortar for 20 minutes and pass it through a 400-mesh sieve, then place it in a muffle furnace and heat it to 1300℃ at a rate of 5℃ / min, hold it at that temperature for 6 hours to obtain (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 The chemical formula of the main phase of the high-entropy rare earth silicate ceramic powder is Dy2SiO5.

[0046] Step 8: Weigh 3g of high-entropy silicate powder and press it into shape in a steel mold with a diameter of 12mm, with a pressure of 100MPa.

[0047] Step 9: The green body is sintered in a muffle furnace at a sintering temperature of 1500℃ for 6 hours to obtain a high-entropy rare earth silicate ceramic block.

[0048] Example 2

[0049] A high-entropy rare earth silicate (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 The preparation method of 2SiO5 ceramic powder is as follows:

[0050] 1. Similar to steps 1-4 of Example 1, a mixed salt solution and a precipitant solution are obtained;

[0051] 2. In step 5, the mixed salt solution is added dropwise to the precipitant solution at a rate of 2 mL / min while stirring. The stirring time is 2 h. The pH value of the system is adjusted to stabilize at 8 by adding a small amount of ammonia or dilute nitric acid solution to generate a large amount of flocculent matter. After stirring thoroughly, the mixture is allowed to stand for 24 h.

[0052] 3. Similar to steps 6-7 in Example 1, (Sm) is obtained. 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 The high-entropy rare earth silicate ceramic powder is Dy2SiO5, and the corresponding phase chemical formula is Dy2SiO5.

[0053] 4. Similar to steps 8-9 in Example 1, press and sinter according to general process parameters to obtain (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 )2SiO5 high-entropy silicate ceramic bulk.

[0054] Example 3

[0055] A method for preparing high-entropy rare earth silicates (Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 The preparation method of 2SiO5 powder ceramic powder, the specific steps are as follows:

[0056] 1. In step 1, according to (Sm 0.2 Eu 0.2Gd 0.2 Ho 0.2 Er 0.2 To determine the stoichiometric ratio of 2SiO5, Sm(NO3)3·6H2O powder, Eu(NO3)3·6H2O powder, Gd(NO3)3·6H2O powder, Ho(NO3)3·5H2O powder, and Er(NO3)3·5H2O powder were weighed out respectively. Then, distilled water was weighed out according to the molar ratio of the total amount of nitrate powder to distilled water of 1:5. The nitrate powder was dissolved in the distilled water and stirred continuously at room temperature for 30 min to ensure complete dissolution, thus obtaining a metal nitrate solution.

[0057] 2. Similar to steps 2-7 of Example 1, TEOS hydrolysis, forward titration, co-precipitation, settling, washing, drying, grinding, and calcination are performed according to general process parameters to obtain (Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 The high-entropy rare earth silicate ceramic powder is Gd2SiO5, and the corresponding main phase has the chemical formula Gd2SiO5.

[0058] 3. Similar to steps 8-9 in Example 1, press and sinter according to general process parameters to obtain (Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 )2SiO5 high-entropy silicate ceramic bulk.

[0059] Example 4

[0060] A method for preparing high-entropy rare earth silicates (Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 The preparation method of 2SiO5 ceramic powder is as follows:

[0061] 1. Similar to steps 1-4 of Example 3, a mixed salt solution and a precipitant solution are obtained;

[0062] 2. In step 5, the mixed salt solution is added dropwise to the precipitant solution at a rate of 2 mL / min while stirring. The stirring time is 2 h. The pH value of the system is adjusted to stabilize at 8 by adding a small amount of ammonia or dilute nitric acid solution to generate a large amount of flocculent matter. After stirring thoroughly, the mixture is allowed to stand for 24 h.

[0063] 3. Similar to steps 6-7 in Example 1, (Sm) is obtained. 0.2 Eu 0.2 Gd0.2 Ho 0.2 Er 0.2 The high-entropy rare earth silicate ceramic powder is Gd2SiO5, and the corresponding phase chemical formula is Gd2SiO5.

[0064] 4. Similar to steps 8-9 in Example 1, press and sinter according to general process parameters to obtain (Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 )2SiO5 high-entropy silicate ceramic bulk.

[0065] Example 5

[0066] A method for preparing high-entropy rare earth silicates (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 The preparation method of 2SiO5 ceramic powder is as follows:

[0067] 1. In step 1, according to (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 To determine the stoichiometric ratio of 2SiO5, Sm(NO3)3·6H2O powder, La(NO3)3·6H2O powder, Nd(NO3)3·6H2O powder, Eu(NO3)3·6H2O powder, and Gd(NO3)3·6H2O powder were weighed out respectively. Then, distilled water was weighed out according to the molar ratio of the total amount of nitrate powder to distilled water of 1:5. The nitrate powder was dissolved in the distilled water and stirred continuously at room temperature for 30 min to ensure complete dissolution, thus obtaining a metal nitrate solution.

[0068] 2. Similar to steps 2-7 of Example 1, TEOS hydrolysis, forward titration, co-precipitation, settling, washing, drying, grinding, and calcination are performed according to general process parameters to obtain (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 The chemical formula of the main phase of the Nd2SiO5 high-entropy silicate ceramic powder is Nd2SiO5.

[0069] 3. Similar to steps 8-9 in Example 1, press and sinter according to general process parameters to obtain (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd0.2 )2SiO5 high-entropy silicate ceramic bulk.

[0070] Example 6

[0071] A method for preparing high-entropy rare earth silicates (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 The preparation method of 2SiO5 ceramic powder is as follows:

[0072] 1. Similar to steps 1-4 of Example 5, a mixed salt solution and a precipitant solution are obtained;

[0073] 2. In step 5, the mixed salt solution is added dropwise to the precipitant solution at a rate of 2 mL / min while stirring. The stirring time is 2 h. The pH value of the system is adjusted to stabilize at 8 by adding a small amount of ammonia or dilute nitric acid solution to generate a large amount of flocculent matter. After stirring thoroughly, the mixture is allowed to stand for 24 h.

[0074] 3. Similar to steps 6-7 in Example 1, (Sm) is obtained. 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 The high-entropy silicate ceramic powder is Nd2SiO5, and the corresponding phase chemical formula is Nd2SiO5.

[0075] 4. Similar to steps 8-9 in Example 1, press and sinter according to general process parameters to obtain (Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )2SiO5 high-entropy silicate ceramic bulk.

[0076] Example 7

[0077] from Figure 1 As can be seen, the XRD diffraction peaks of each high-entropy rare earth silicate ceramic powder prepared by reverse titration are consistent with the standard silicate card, and there are no obvious impurity peaks. A small amount of second phase appears in the high-entropy silicate powder prepared by forward titration, indicating that the high-entropy rare earth silicate ceramic powder prepared by reverse titration has a single crystal structure.

[0078] Figure 1 In the diagram, Figure a corresponds to Embodiment 2 and Embodiment 1 from top to bottom, Figure b corresponds to Embodiment 4 and Embodiment 3 from top to bottom, and Figure c corresponds to Embodiment 6 and Embodiment 5 from top to bottom.

[0079] from Figure 2As can be seen, the high-entropy rare-earth silicate ceramic powder particles have good dispersion.

[0080] from Figure 3 As can be seen, the grain size distribution of each high-entropy rare earth silicate ceramic powder is uniform, with submicron-level grain size;

[0081] from Figure 4 As can be seen, the elements in each high-entropy rare earth silicate ceramic powder are evenly distributed with no obvious elemental segregation, and the relative atomic percentage of each element is basically consistent with the experimental design ratio.

[0082] Figure 2-4 In the figures, a corresponds to Example 1, b corresponds to Example 3, c corresponds to Example 5, d corresponds to Example 2, e corresponds to Example 4, and f corresponds to Example 6.

[0083] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A high-entropy rare-earth silicate ceramic powder, characterized in that: The chemical composition of the high-entropy rare-earth silicate ceramic powder includes the following: (Sm 0.2 Yb 0.2 Tm 0.2 Dy 0.2 Er 0.2 )2SiO5,(Sm 0.2 Eu 0.2 Gd 0.2 Ho 0.2 Er 0.2 )2SiO5,(Sm 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )2SiO 5。 2. The high-entropy rare-earth silicate ceramic powder according to claim 1, characterized in that, The high-entropy rare-earth silicate ceramic powder has a monoclinic structure, uniform element distribution, and an average grain size of 167.22~313.41 nm.

3. A method for preparing high-entropy rare-earth silicate ceramic powder according to claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh out nitrate powder and distilled water in a molar ratio of total rare earth nitrate powder to distilled water of 1:5~7. Dissolve the weighed nitrate powder in distilled water to obtain a metal nitrate solution. S2. Measure TEOS, anhydrous ethanol, and distilled water in a volume ratio of 1:1.5~2.5:3.5~4.

5. Mix the measured TEOS, anhydrous ethanol, and distilled water and stir until homogeneous to obtain a TEOS hydrolysis solution. S3. Weigh out ammonium carbonate powder and distilled water in a molar ratio of ammonium carbonate powder to distilled water of 1:5~7. Dissolve the weighed ammonium carbonate powder in distilled water to obtain a precipitant solution. S4. Mix the metal nitrate solution with the TEOS hydrolysis solution to obtain a mixed salt precursor solution; S5. Forward titration process: Add ammonium carbonate precipitant dropwise to the precursor solution at a rate of 1~2 mL / min, and adjust the pH value to 7~8 using ammonia and dilute nitric acid. Flocculent precipitate is generated in the mixture. Stir it with a magnetic stirrer for 2~4 hours at a stirring rate of 400~500 r / min. After the mixture is thoroughly stirred, let it stand for 20~24 hours to ensure complete precipitation. S6. Reverse titration process: The precursor solution is added dropwise to the precipitant solution at a rate of 1~2 mL / min, and the pH value is adjusted to 7~8 using ammonia and dilute nitric acid. Flocculent precipitate is generated in the mixture. The mixture is stirred with a magnetic stirrer for 2~4 hours at a stirring rate of 400~500 r / min. After the mixture is thoroughly stirred, it is allowed to stand for 20~24 hours to ensure complete precipitation. S7. After co-precipitation, remove the supernatant and transfer the suspension to a centrifuge tube. Centrifuge and wash the suspension with distilled water and anhydrous ethanol in sequence, repeating the washing until pH=6~7. S8. Pour the cleaned suspension into an evaporating dish and dry it in a drying oven at 90~110℃ for 12~14h to obtain solid powder. Grind and sieve the powder, and then place it in a muffle furnace and heat it to 1200~1400℃ at a rate of 5℃ / min. Hold it at this temperature for 6~8h to obtain high entropy rare earth silicate ceramic powder. S9. Weigh 3~3.2g of high-entropy silicate powder and press it into shape in a steel mold with a diameter of 12mm, with a pressure of 100~120MPa; S10. The green body is sintered in a muffle furnace at a sintering temperature of 1500~1600℃ for 5~6 hours to obtain a high-entropy rare earth silicate ceramic block.

4. The method for preparing high-entropy rare-earth silicate ceramic powder according to claim 3, characterized in that, In S1, the nitrate powder is a mixture of five powders selected from Sm(NO3)3·6H2O, Yb(NO3)3·5H2O, Tm(NO3)3·6H2O, Dy(NO3)3·6H2O, Er(NO3)3·5H2O, Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, Ho(NO3)3·5H2O, Nd(NO3)3·6H2O, and La(NO3)3·6H2O in a molar ratio of 1:1:1:1:1:

1.

5. The method for preparing high-entropy rare-earth silicate ceramic powder according to claim 3, characterized in that, In S1 and S2, the molar ratio of Si to rare earth elements in the TEOS hydrolysis solution and the metal nitrate solution is 11~13:

20.

6. The method for preparing high-entropy rare-earth silicate ceramic powder according to claim 3, characterized in that, In S1 and S3, the molar ratio of ammonium carbonate powder to metal nitrate solution is 1.5~1.8:

1.

7. The method for preparing high-entropy rare-earth silicate ceramic powder according to claim 3, characterized in that, In step S8, the grinding and sieving of the solid powder includes the following steps: (1) The powder sample was ground using an agate mortar and pestle for 30-50 minutes. (2) The ground powder is sieved through a sieve with a mesh size of 300~600.

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