CN113402270B - Preparation method of multiphase nanocrystalline ceramic composite material - Google Patents

Preparation method of multiphase nanocrystalline ceramic composite material Download PDF

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CN113402270B
CN113402270B CN202110661592.1A CN202110661592A CN113402270B CN 113402270 B CN113402270 B CN 113402270B CN 202110661592 A CN202110661592 A CN 202110661592A CN 113402270 B CN113402270 B CN 113402270B
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魏玉婷
李玉红
何彩云
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Lanzhou University
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Abstract

The invention discloses a preparation method of a multiphase nanocrystalline ceramic composite material, and preferably Y is prepared2Ti2O7Nanopowder of yttrium oxide (Y)2O399.99%), tetrabutyl titanate (C)16H36O4Ti, 99%) as raw material, anhydrous citric acid (C)6H8O799.50%) as chelating agent, absolute ethyl alcohol (C)2H6O, 99.70%) as solvent for preparing Y2Ti2O7A nanopowder; then from Y2Ti2O7、ZrO2(99.99％,50nm)、Al2O3And (99.99%, 20nm) powder is mixed to synthesize the multiphase nanocrystalline ceramic composite material. The preparation process is simple, and the process complexity is reduced; the ideal nanocrystalline ceramic material with slow grain growth at high temperature can be obtained by the method, a second phase is not generated in the sintering process, and the average particle size is less than 100 nm.

Description

Preparation method of multiphase nanocrystalline ceramic composite material
Technical Field
The invention relates to the field of pyrochlore ceramic materials, in particular to a preparation method of a multiphase nanocrystalline ceramic composite material.
Background
The interface in the material has the characteristic of providing annihilation space for irradiation defects, so that the irradiation resistance of the material can be fundamentally improved by introducing the grain boundary. At present, the international research on the design and development of the radiation-resistant material is mainly divided into three categories, namely a nano porous structure material introduced with a high-density free surface, a nano multilayer film material introduced with a high-density heterogeneous interface and a nano crystal material introduced with a high-density grain boundary. Generally, the capability of the nano porous structure material for eliminating the irradiation defects is closely related to the size of the skeleton and the irradiation conditions thereof, and most of the nano porous structure materials are prepared by adopting a dealloying process, so that the types of available materials are limited. Similarly, the magnetron sputtering method mainly adopted for preparing the nano multilayer film needs to be carried out under the conditions of high vacuum and high temperature, the equipment is expensive, and the process is complex. In contrast, the process for preparing the nanocrystalline material is simpler and is easy for industrial production. And researches show that compared with the traditional large-grain ceramic material, the nanocrystalline ceramic is expected to show better optical, magnetic, mechanical and electrical properties due to the larger surface area to volume ratio. However, the nanocrystalline ceramic material may undergo grain coarsening under irradiation or high temperature conditions, which may affect its electrical, hardness, radiation resistance, and thermal stability properties. Therefore, research on preparing nanocrystalline ceramic materials with slow grain growth at high temperature has become a problem to be solved urgently.
Disclosure of Invention
In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for preparing a multi-phase nanocrystalline ceramic composite material by adding a dopant to inhibit grain growth without producing a second phase during sintering. The preparation method is simple and convenient to popularize.
A preparation method of a multiphase nanocrystalline ceramic composite material comprises the following steps:
s1, weighing the following raw materials:
Y2O3+2C16H36O4Ti+7.5C6H8O7→Y2Ti2O7
weighing a proper amount of yttrium oxide Y according to a reaction equation and a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7To prepare nano Y2Ti2O7Powder;
s2, dispersing the weighed yttrium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid for assisting dissolution while stirring, and adjusting the temperature to 100 ℃ to volatilize excessive nitric acid after stirring to be transparent to obtain a solution A;
s3, completely dissolving anhydrous citric acid serving as a chelating agent in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and vigorously stirring the mixed solution until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process, enabling the mixed solution to generate white floccules, and dropwise adding a small amount of ammonia water to adjust the pH value of the solution to 6.7; putting the mixed solution in a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally changing the solution into milky white gel;
s5, putting the gel into a drying oven, and drying at 120 ℃ for 24-48h until yellow green xerogel is obtained;
s6, calcining the xerogel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving the heat at 1000 ℃ for 1.0h, setting the temperature drop rate to be 3 ℃/min, and finally obtaining Y2Ti2O7Primarily grinding white nano powder in a mortar, and performing XRD and TEM characterization;
s7, mixing Y2Ti2O7And ZrO2、Al2O3Mixing the nanometer powder according to an equal molar ratio, ball-milling for 30min each time for 4 times in a ball mill, and fully mixing the powder;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, annealing for 2h at 1000 ℃ to remove residual carbon and relax stress in the sintering process, and obtaining the multiphase nanocrystalline ceramic material.
Preferably, the yttrium oxide used has a purity of 99.99% by mass; the purity of tetrabutyl titanate is 99 percent by mass percent; the anhydrous citric acid has the mass percent purity of 99.50 percent(ii) a The purity of the absolute ethyl alcohol in percentage by mass is 99.70 percent; ZrO (ZrO)2The average particle size of the powder is 50nm, and the mass percent purity is 99.99 percent; al (Al)2O3The average particle size of the powder was 20nm and the purity by mass percent was 99.99%.
Preferably, the product obtained in step 9 is characterized by XRD and SEM.
Preferably, the average particle size of the multiphase nanocrystalline ceramic material prepared by the invention reaches 99.0554 nm; after the high-temperature grain growth experiment, the grain growth rate is 1.7-1.8.
The invention has the beneficial effects that:
(1) y with the grain diameter within 30nm is synthesized by a simple process2Ti2O7A powder;
(2) provides a preparation method of a multiphase nanocrystalline ceramic composite material, and the nanocrystalline ceramic material with slow grain growth at high temperature can be obtained by the method. The method has simple preparation process and effectively inhibits the growth of crystal grains.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a flow chart of a process for preparing a multi-phase nanocrystalline ceramic composite;
FIG. 2 is Y2Ti2O7XRD characterization pattern of nanopowder;
FIG. 3 is Y2Ti2O7TEM characterization of the nanopowder;
FIG. 4 is an XRD characterization plot of a multiphase nanocrystalline ceramic composite sample;
FIG. 5 is an SEM representation of a multiphase nanocrystalline ceramic composite sample;
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Example 1:
a preparation method of a multiphase nanocrystalline ceramic composite material comprises the following steps:
first selection for preparing Y2Ti2O7Nanopowder of yttrium oxide (Y)2O399.99%), tetrabutyl titanate (C)16H36O4Ti, 99%) as raw material, anhydrous citric acid (C)6H8O799.50%) as chelating agent, absolute ethyl alcohol (C)2H6O, 99.70%) as solvent for preparing Y2Ti2O7A nanopowder; then from Y2Ti2O7、ZrO2(99.99％,50nm)、Al2O3Mixing (99.99%, 20nm) powder to synthesize a multiphase nanocrystalline ceramic composite material; the method comprises the following specific steps:
s1, weighing the following raw materials:
Y2O3+2C16H36O4Ti+7.5C6H8O7→Y2Ti2O7
weighing a proper amount of yttrium oxide Y according to a reaction equation and a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7；
S2, dispersing the weighed yttrium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid while stirring to assist dissolution, adjusting the temperature to 100 ℃ after stirring to be transparent to volatilize excessive nitric acid, and obtaining a solution A;
s3, completely dissolving citric acid in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and stirring the mixed solution vigorously until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process, enabling the mixed solution to generate white floccules, and dropwise adding a small amount of ammonia water to adjust the pH value of the solution to 6.7; putting the mixed solution in a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally becoming milky gel;
s5, putting the gel into a drying oven, and drying at 120 ℃ for 24-48h until yellow green xerogel is obtained;
s6, calcining the xerogel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving the heat at 1000 ℃ for 1.0h, setting the temperature drop rate to be 3 ℃/min, and finally obtaining Y2Ti2O7Grinding the white nano powder, and then performing XRD and TEM characterization;
s7, mixing Y2Ti2O7And ZrO2、Al2O3Mixing the nanometer powder according to an equal molar ratio, ball-milling for 30min each time for 4 times in a ball mill, and fully mixing the powder;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, because a graphite mold is used in the sintering process, the sintered sample needs to be polished to remove graphite on the surface, and then the sample is annealed for 2 hours at 1000 ℃ to remove residual carbon and relax the stress in the sintering process, so that the multiphase nanocrystalline ceramic composite material is prepared; and (4) carrying out XRD and SEM characterization on the synthesized product.
XRD analysis and SEM observation are carried out on the multiphase nanocrystalline ceramic material prepared by the method, and the test results are shown in figures 4 and 5. No second phase is generated during sintering, and the average particle size reaches 99.0554 nm; after the high-temperature grain growth experiment, the grain growth rate is 1.7-1.8. The method is used for obtaining the ideal multiphase nanocrystalline ceramic material with slow grain growth at high temperature.
Example 2:
lu is carried out according to the steps2Ti2O7，Al2O3And ZrO2Preparation of a multiphase nanocrystalline sample comprising the steps of:
s1, weighing the following raw materials:
Lu2O3+2C16H36O4Ti+7.5C6H8O7→Lu2Ti2O7
weighing a proper amount of lutetium oxide Lu according to a reaction equation and a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7；
S2, dispersing the weighed lutetium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid for assisting dissolution while stirring, and adjusting the temperature to 100 ℃ for volatilizing excessive nitric acid after stirring to be transparent to obtain a solution A;
s3, completely dissolving citric acid in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and stirring the mixed solution vigorously until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process until the solution is transparent, putting the mixed solution into a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally becoming milky gel;
s5, putting the gel into a drying oven, and drying at 120 ℃ for 24-48h until yellow green xerogel is obtained;
s6, calcining the xerogel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving the heat at 1000 ℃ for 1.0h, setting the temperature drop rate to be 3 ℃/min, and finally obtaining Lu2Ti2O7White nano powder;
s7, mixing Lu2Ti2O7、Al2O3And ZrO2Mixing the nanometer powder according to an equal molar ratio, ball-milling for 30min each time for 4 times in a ball mill, and fully mixing the powder;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, annealing at 1000 ℃ for 2h to remove residual carbon and relax the stress during sintering.
Wherein, the mass percent purity of the lutetium oxide is 99.99 percent; the purity of tetrabutyl titanate is 99 percent by mass percent; the purity of the anhydrous citric acid in percentage by mass is 99.50 percent; the purity of the absolute ethyl alcohol in percentage by mass is 99.70 percent; the average particle size of the zirconia powder is 50nm, and the mass percent purity is 99.99 percent; the alumina powder had an average particle size of 20nm and a purity of 99.99% by mass.
Example 3:
carrying out Y according to the above steps2Ti2O7And ZrO2Preparation of a two-phase nanocrystalline sample comprising the steps of:
s1, weighing the following raw materials:
Y2O3+2C16H36O4Ti+7.5C6H8O7→Y2Ti2O7
weighing a proper amount of yttrium oxide Y according to a reaction equation and a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7；
S2, dispersing the weighed yttrium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid for assisting dissolution while stirring, and adjusting the temperature to 100 ℃ to volatilize excessive nitric acid after stirring to be transparent to obtain a solution A;
s3, completely dissolving citric acid in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and stirring the mixed solution vigorously until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process, enabling the mixed solution to generate white floccules, and dropwise adding a small amount of ammonia water to adjust the pH value of the solution to 6.7; putting the mixed solution in a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally becoming milky gel;
s5, putting the gel into a drying oven, and drying at 120 ℃ for 24-48h until yellow green xerogel is obtained;
s6, calcining the xerogel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving heat for 1.0h at 1000 ℃, setting the temperature drop rate to be 3 ℃/min, and finally obtaining Y2Ti2O7Grinding the white nano powder, and then performing XRD and TEM characterization;
s7, mixing Y2Ti2O7And ZrO2Mixing the nanometer powder according to an equal molar ratio, ball-milling for 30min each time for 4 times in a ball mill, and fully mixing the powder;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, annealing at 1000 ℃ for 2h to remove residual carbon and relax the stress during sintering.
Comparative example:
carrying out Y according to the above steps2Ti2O7The preparation of the single-phase nanocrystalline sample comprises the following steps:
s1, weighing the following raw materials:
Y2O3+2C16H36O4Ti+7.5C6H8O7→Y2Ti2O7
according to the reaction equationWeighing a proper amount of yttrium oxide Y according to a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7；
S2, dispersing the weighed yttrium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid for assisting dissolution while stirring, and adjusting the temperature to 100 ℃ to volatilize excessive nitric acid after stirring to be transparent to obtain a solution A;
s3, completely dissolving citric acid in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and stirring the mixed solution vigorously until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process, enabling the mixed solution to generate white floccules, and dropwise adding a small amount of ammonia water to adjust the pH value of the solution to 6.7; putting the mixed solution in a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally becoming milky gel;
s5, putting the gel into a drying oven, and drying for 24-48h at 120 ℃ until obtaining yellow green xerogel;
s6, calcining the xerogel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving the heat at 1000 ℃ for 1.0h, setting the temperature drop rate to be 3 ℃/min, and finally obtaining Y2Ti2O7Grinding the white nano powder, and then performing XRD and TEM characterization;
s7, mixing Y2Ti2O7Ball-milling the nanometer powder in a ball mill for 4 times, each time for 30 min;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, annealing at 1000 ℃ for 2h to remove residual carbon and relax the stress during sintering.
Experimental data
The multiphase nanocrystalline ceramic composites of examples 1 and 2 of the present invention, the two-phase nanocrystalline samples of example 3, and the single-phase nanocrystalline samples of the comparative example were subjected to high-temperature grain growth experiments. The experimental conditions are as follows: 1350 deg.C, 30 min. SEM characterization is carried out before and after the crystal grains grow, and the average grain diameter is counted to obtain the crystal grain growth rate shown in the table.
Figure BDA0003115605320000071
As can be seen from the above table, the grain growth rates of the multiphase nanocrystalline ceramic composites are 1.794 and 1.899, respectively, the grain growth rate of the two-phase nanocrystalline ceramic composite is 3.423, and Y is2Ti2O7The growth rate of the single-phase nanocrystalline ceramic reaches 9.198, and the grain coarsening resistance of the multiphase nanocrystalline ceramic composite material is greatly enhanced.
As shown in the drawing, Y synthesized in example 1 of the present invention was introduced2Ti2O7The nanometer powder is characterized by XRD and TEM, and the results are shown in figures 2 and 3. The sample synthesis is successful and the particle size is within 100nm, so the specific grain size is 22.754nm calculated by using the Sherle formula.
XRD characterization is carried out on the multiphase nanocrystalline ceramic composite material prepared in the embodiment 1 of the invention, the result is shown in figure 4, and only Y in the sample can be seen2Ti2O7、ZrO2And Al2O3Three phases, no second phase is generated; the multiphase nanocrystalline ceramic composite was SEM characterized and the results are shown in FIG. 5, from which the average particle size was statistically 99.0554 nm.
The invention synthesizes Y with the grain diameter within 30nm by using a simpler preparation method2Ti2O7Powder and a preparation method of the multiphase nanocrystalline ceramic material, which is provided simultaneously, the preparation process of the method is simple, and the process complexity is reduced; the nanocrystalline ceramic material with slow grain growth at high temperature can be obtained by the method, a second phase is not generated in the sintering process, and the average particle size is less than 100 nm.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (5)

1. The preparation method of the multiphase nanocrystalline ceramic composite material is characterized by comprising the following steps:
s1, weighing the following raw materials:
Y2O3+2C16H36O4Ti+7.5C6H8O7→Y2Ti2O7
weighing a proper amount of yttrium oxide Y according to a reaction equation and a certain molar ratio2O3Tetrabutyl titanate C16H36O4Ti and anhydrous citric acid C6H8O7To prepare nano Y2Ti2O7Powder;
s2, dispersing the weighed yttrium oxide in deionized water, placing the deionized water on a constant-temperature magnetic stirrer for stirring, adjusting the temperature to 80 ℃, dropwise adding a small amount of concentrated nitric acid for assisting dissolution while stirring, and adjusting the temperature to 100 ℃ to volatilize excessive nitric acid after stirring to be transparent to obtain a solution A;
s3, completely dissolving anhydrous citric acid serving as a chelating agent in absolute ethyl alcohol until the solution is transparent, dropwise adding tetrabutyl titanate with corresponding stoichiometric amount into the solution, and vigorously stirring the mixed solution until a transparent solution B is obtained;
s4, slowly adding the solution A into the solution B, continuously stirring in the process, enabling the mixed solution to generate white floccules, and dropwise adding a small amount of ammonia water to adjust the pH value of the solution to 6.7; putting the mixed solution in a water bath kettle at 80 ℃ for water bath, volatilizing redundant solute and water, gradually thickening the solution, and finally becoming milky gel;
s5, putting the gel into a drying oven, and drying at 120 ℃ for 24-48h until yellow green xerogel is obtained;
s6, dryingCalcining the gel, setting the temperature rise rate of a muffle furnace to be 5 ℃/min, preserving the heat for 1.0h at 1000 ℃, setting the temperature reduction rate to be 3 ℃/min, and finally obtaining Y2Ti2O7Primarily grinding white nano powder in a mortar, and performing XRD and TEM characterization;
s7, mixing Y2Ti2O7And ZrO2、Al2O3Mixing the nanometer powder according to an equal molar ratio, ball-milling for 30min each time for 4 times in a ball mill, and fully mixing the powder;
s8, weighing 10g of the powder ball-milled in the step S7, putting the powder into a graphite mold with the diameter of 30mm, putting the graphite mold into SPS (semi-continuous casting) for heating, keeping the temperature at 1300 ℃ for 5min, setting the uniaxial pressure to be 40Mpa, setting the temperature rise rate to be 100 ℃/min, setting the temperature reduction rate to be 100 ℃/min, and keeping the atmosphere in vacuum;
s9, annealing for 2h at 1000 ℃ to remove residual carbon and relax stress in the sintering process, and obtaining the multiphase nanocrystalline ceramic composite material.
2. The method according to claim 1, wherein the yttrium oxide has a purity of 99.99% by mass; the purity of tetrabutyl titanate is 99 percent by mass percent; the purity of the anhydrous citric acid in percentage by mass is 99.50 percent; the purity of the absolute ethyl alcohol in percentage by mass is 99.70 percent; the average particle size of the zirconia powder is 50nm, and the mass percent purity is 99.99 percent; the alumina powder had an average particle size of 20nm and a purity of 99.99% by mass.
3. The method of claim 1, wherein the XRD and SEM characterization of the product obtained in step 9 is performed.
4. The method for preparing the multiphase nanocrystalline ceramic composite material according to claim 1, wherein the average grain size of the prepared multiphase nanocrystalline ceramic material reaches 99.0554 nm; after the high-temperature grain growth experiment, the grain growth rate is 1.7-1.8.
5. The method of claim 1, wherein steps S1-S6 are also applicable to Lu preparation2Ti2O7Nanopowder, the reaction equation:
Lu2O3+2C16H36O4Ti+7.5C6H8O7→Lu2Ti2O7。
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