A b-site doped high-entropy strontium titanate ceramic powder and a preparation method thereof

Abstract

The application discloses B-site doped high-entropy strontium titanate ceramic powder and a preparation method thereof, and belongs to the technical field of high-entropy ceramic materials. The chemical formula of the B-site doped high-entropy strontium titanate ceramic provided by the application is Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3. The preparation method of the ceramic powder is as follows: strontium carbonate and the rest of metal oxides are weighed according to the stoichiometric ratio of the chemical formula, mixed and ball milled to obtain a mixed powder, the mixed powder is stirred uniformly by adding gum arabic, and then granulation, sintering and sieving are performed to obtain the B-site doped high-entropy strontium titanate powder. The four elements of Zr, Ti, In and Ta are doped in the B-site lattice of strontium titanate (SrTiO3) in the application, high-entropy ceramic is formed, the degree of disorder is increased, and the dielectric constant is expected to be improved and the dielectric loss is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-entropy ceramic materials, and particularly relates to a B-site doped high-entropy strontium titanate ceramic powder and a preparation method thereof. BACKGROUND

[0002] Perovskite-type composite oxides are a kind of compounds with the same structure as perovskite, which can be represented by AB03, the A site is an alkaline earth element, the cation is in a 12-coordinated structure, located in the cavity composed of octahedrons; the B site is a transition metal element, the cation forms an octahedral coordination with six oxygen ions. Perovskite composite oxide high-entropy material refers to a perovskite structure in which the B site is occupied by four to five kinds of metal ions at the same molar ratio. The large number of possible arrangements of different atoms in the B site leads to disorder (high entropy).

[0003] High-entropy ceramic material is a multi-principal element solid solution ceramic formed by doping four to five or more elements at the same ratio. It has high dielectric constant and low dielectric loss, belongs to high dielectric constant ceramic material, and has high application potential in ultra-high temperature material and new energy material field. However, high-entropy ceramic synthesis is difficult, and currently, the only perovskite-type high-entropy ceramic material is high-entropy lead zirconate ceramic material, which contains lead element, resulting in poor thermal stability, low mechanical strength and unsatisfactory dielectric performance of the ceramic material. Therefore, it is necessary to provide a new perovskite-type high-entropy ceramic powder material. SUMMARY

[0004] The purpose of the present application is to provide a B-site doped high-entropy strontium titanate ceramic powder to solve the problems existing in the prior art, so that the high-entropy ceramic material has high dielectric constant and low dielectric loss at the same time.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] The present application provides a B-site doped high-entropy strontium titanate ceramic powder, the chemical formula of which is: Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3. The high-entropy ceramic is of ABO3 type perovskite structure, and the four metal atoms occupying the B site are Zr, Ti, In and Ta in equal molar ratio.

[0007] The present application also provides a preparation method of the B-site doped high-entropy strontium titanate ceramic powder, which comprises the following steps: weighing SrCO3, TiO2, In2O3, Ta2O5 and ZrO2 powders according to the stoichiometric ratio of the chemical formula, mixing and ball milling, adding a binder and stirring uniformly to obtain a ceramic slurry, then granulating, sintering and sieving to obtain the B-site doped high-entropy strontium titanate ceramic powder.

[0008] Preferably, the mixed ball milling uses anhydrous ethanol and zirconium oxide beads as the ball milling medium, and the mass ratio of the anhydrous ethanol, the zirconium oxide beads and the raw materials is (4-5):(4-5):1, wherein the ball milling speed is 300-400 rpm, and the ball milling time is 12-24 hours.

[0009] Preferably, the binder is gum arabic, and the mass ratio of the gum arabic and the ceramic slurry is (4-5):100.

[0010] Preferably, the granulation comprises placing the ceramic slurry obtained after stirring with gum arabic into a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower is 200-250℃, the outlet air temperature of the drying tower is 80-120℃, and the atomization speed of the high-speed centrifugal spray drying tower during the granulation is 15,600-18,000 rpm, to obtain ceramic particles.

[0011] Preferably, the sintering condition is that the temperature is raised from room temperature to 1,350-1,400℃ at a temperature raising rate of 6℃ / min, and then the temperature is kept for 3-4 hours, and then the furnace is cooled to room temperature.

[0012] Preferably, the sieving is sieving through an 80-100 mesh sieve.

[0013] Preferably, the method for preparing the B-site doped high-entropy strontium titanate ceramic powder comprises the following steps:

[0014] (1) Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3 stoichiometrically weighed SrCO3, TiO2, Ta2O5, In2O3 and ZrO2 powders; the powders were placed into a ball mill, and ball milling was performed for 12 hours at a ball milling speed of 300 rpm, with the mass ratio of the zirconia beads, the anhydrous ethanol and the raw material powders being 5:5:1, to obtain a ceramic slurry; then gum arabic was added to the obtained ceramic slurry and stirred for 30 minutes, with the mass ratio of the gum arabic and the ceramic slurry being 5:100, to obtain a stirred ceramic slurry.

[0015] (2) The stirred ceramic slurry obtained in step (1) was placed into a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower was 220℃, the outlet air temperature of the drying tower was 110℃, and the atomization speed of the high-speed centrifugal spray drying tower during the granulation was 18,000 rpm, to obtain ceramic particles.

[0016] (3) Place the ceramic particles obtained in step (2) into a crucible, place the crucible into a muffle furnace, heat it to 1360°C at a heating rate of 6°C / min, keep it in the muffle furnace for 4 hours, then cool it to room temperature with the furnace, and then pass the sintered powder through an 80-mesh sieve to obtain B-site doped high-entropy ceramic powder.

[0017] The present invention discloses the following technical effects:

[0018] (1) The preparation method of the present invention uses the target element oxide as raw material, mixes it by ball milling, and then prepares the B-site doped high-entropy strontium titanate ceramic powder by high-temperature sintering. The sintering process does not require specific atmosphere control and does not require the addition of sintering aids. The process flow is short, the preparation cost is low, and the preparation efficiency is high.

[0019] (2) In the field of dielectric ceramics, strontium titanate has advantages such as strong thermal stability, high hardness and toughness, and high dielectric constant. High-entropy strontium titanate has a performance advantage over high-entropy lead zirconate ceramic materials. In this invention, Zr, Ti, In, and Ta are selected as B-site doping elements for strontium titanate to prepare high-entropy strontium titanate ceramic powder. The four elements are doped into the B-site lattice of strontium titanate in an equimolar ratio, thereby causing a lattice distortion effect in strontium titanate, increasing its disorder, further improving the dielectric constant, and reducing dielectric loss.

[0020] (3) The chemical formula of the high-entropy strontium titanate ceramic prepared by this invention is: Sr(Zr) 0.25 Ti 0.25 In 0.25 Ta 0.25 O3 has a stable perovskite structure and better mechanical properties. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in 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.

[0022] Figure 1 The image shows the XRD pattern of the high-entropy ceramic powder prepared in Example 1.

[0023] Figure 2 The image shows a SEM image of the high-entropy ceramic powder prepared in Example 1.

[0024] Figure 3 Sr(Zr) prepared in Example 1 0.25 Ti 0.25 In 0.25 Ta 0.25a dielectric constant map and a dielectric loss map of O3. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be illustrative of certain aspects, features and embodiments of the present application, but not a limitation thereof.

[0026] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value of the parameter is also specifically included within the scope of the present application. The intervening values of the parameter are combined with a stated value of the parameter in range form. These are only exemplary of the various assumed but equivalent implementations that are encompassed by the present application. Although each aspect, feature, and embodiment described above has a disadvantage, acceptable to manufacturers, users or others, no single feature or embodiment is essential to the practice of the application.

[0027] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice of the present application, the preferred methods and materials are described herein. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference to the extent allowed by law for disclosure and description of methods and / or materials related to the described application. In the case of conflict between the description herein and the incorporated document, the present description controls.

[0028] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0029] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0030] The embodiment of the present application provides a preparation method of B-site doped high-entropy strontium titanate ceramic powder, which comprises the following steps: weighing SrCO3, TiO2, Ta2O5, In2O3 and ZrO2 powders according to the stoichiometric ratio of a chemical formula, mixing and ball milling, adding a binder and stirring uniformly to obtain a ceramic slurry, and then granulating, sintering and sieving to obtain the B-site doped high-entropy strontium titanate ceramic powder.

[0031] In some embodiments of the present application, the mixing ball milling uses anhydrous ethanol and zirconium oxide beads as the ball milling medium, and the mass ratio of the anhydrous ethanol, the zirconium oxide beads and the raw materials is (4-5):(4-5):1, wherein the ball milling speed is 300-400 rpm, and the ball milling time is 12-24 hours.

[0032] In some embodiments of the present application, the binder is gum arabic, and the mass ratio of the gum arabic and the ceramic slurry is 4:100.

[0033] As a typical but non-limiting example, the granulation includes placing the ceramic slurry obtained after stirring with gum arabic into a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower is 200-250℃, the outlet air temperature of the drying tower is 80-120℃, and the atomization speed of the high-speed centrifugal spray drying tower during the granulation is 15,600-18,000 rpm, to obtain ceramic particles.

[0034] In some embodiments of the present application, the sintering condition is as follows: the temperature is raised from room temperature to 1,350-1,400℃ at a temperature raising rate of 6℃ / min, and then the temperature is kept for 3-4 hours, and then the furnace is cooled to room temperature.

[0035] In some embodiments of the present application, the sieving is sieving through an 80-100 mesh sieve.

[0036] Embodiment 1

[0037] A preparation method of a B-site doped high-entropy strontium titanate ceramic powder, and the specific steps are as follows:

[0038] (1) Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3 stoichiometric ratio of SrCO3, TiO2, Ta2O5, In2O3 and ZrO2 powders; the above powders are put into a ball mill, and ball milling mixing is performed for 12 hours according to the mass ratio of zirconia beads, anhydrous ethanol and the above powders of 5:5:1, and the ball mill speed is 300 rpm, to obtain a ceramic slurry; then gum arabic is added to the ceramic slurry for stirring, the stirring time is 30 minutes, the mass ratio of the gum arabic and the ceramic slurry is 5:100, to obtain a stirred ceramic slurry;

[0039] (2) the stirred ceramic slurry obtained in step (1) is placed in a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower is 220℃, the outlet air temperature of the drying tower is 110℃, and the atomization speed of the high-speed centrifugal spray drying tower during the granulation is 18,000 rpm, to obtain ceramic particles;

[0040] (3) Put the ceramic particles obtained in step (2) into a crucible, put the crucible into a muffle furnace, and heat to 1360℃ at a heating rate of 6℃ / min, keep in the muffle furnace for 4 hours, then cool to room temperature with the furnace, then sieve the sintered powder through an 80-mesh sieve to obtain the B-site doped high-entropy ceramic powder.

[0041] The high-entropy ceramic powder prepared in Example 1 was analyzed by XRD, and the results are shown in FIG. 1. Figure 1 As can be seen from the figure, the high-entropy ceramic powder prepared in Example 1 is single-phase perovskite structure.

[0042] The high-entropy ceramic powder prepared in Example 1 was analyzed by scanning electron microscopy, and the results are shown in FIG. 2. Figure 2 As can be seen from the figure, the sphericity of the prepared high-entropy ceramic powder is good.

[0043] Example 2

[0044] A method for preparing a B-site doped high-entropy strontium titanate ceramic powder, the specific steps are as follows:

[0045] (1) Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3 stoichiometric ratio of SrCO3, TiO2, In2O3, Ta2O5 and ZrO2 powder; put the above-mentioned powder into a ball mill, and ball mill mix according to the mass ratio of zirconia ball, anhydrous ethanol and the above-mentioned powder is 5:5:1 for 12 hours, the rotation speed of the ball mill is 300 revolutions / minute, to obtain ceramic slurry; then add gum arabic to the ceramic slurry and stir for 30 minutes, the mass ratio of gum arabic to ceramic slurry is 5:100, to obtain the stirred ceramic slurry;

[0046] (2) Put the stirred ceramic slurry obtained in step (1) into a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower is 230℃, the outlet air temperature of the drying tower is 110℃, the atomization rotation speed of the high-speed centrifugal spray drying tower during granulation is 18000rpm, to obtain ceramic particles;

[0047] (3) Put the ceramic particles obtained in step (2) into a crucible, put the crucible into a muffle furnace, and heat to 1370℃ at a heating rate of 6℃ / min, keep in the muffle furnace for 3.4 hours, then cool to room temperature with the furnace, then sieve the sintered powder through a 100-mesh sieve to obtain the doped high-entropy ceramic powder.

[0048] Example 3

[0049] A method for preparing a B-site doped high-entropy strontium titanate ceramic powder, the specific steps are as follows:

[0050] (1) According to the stoichiometric ratio of Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3, SrCO3, TiO2, In2O3, Ta2O5 and ZrO2 powders are weighed; the powders are put into a ball mill, and ball-mixed for 12 hours at a mass ratio of zirconia balls, anhydrous ethanol and the powders of 5:5:1, and a rotation speed of 300 rpm, to obtain a ceramic slurry; then gum arabic is added to the ceramic slurry for stirring for 30 minutes, at a mass ratio of gum arabic to the ceramic slurry of 5:100, to obtain a stirred ceramic slurry;

[0051] (2) The stirred ceramic slurry obtained in step (1) is put into a high-speed centrifugal spray drying tower for granulation, at an inlet air temperature of 200℃ and an outlet air temperature of 105℃, and at an atomization rotation speed of 18000 rpm in the high-speed centrifugal spray drying tower, to obtain ceramic particles;

[0052] (3) The ceramic particles obtained in step (2) are put into a crucible, and the crucible is put into a muffle furnace, heated to 1380℃ at a heating rate of 6℃ / min, and kept in the muffle furnace for 3 hours, then cooled to room temperature, and then the sintered powder is sieved through a 100-mesh sieve, to obtain a doped high-entropy ceramic powder.

[0053] Test Example

[0054] The high-entropy ceramic powders obtained in Examples 1-3 and the Comparative Example are pressed into ceramic discs by a press machine at a pressure of 150 MPa and a pressure holding time of 10 min, to obtain ceramic discs with a diameter of 10 mm, and a layer of gold electrode is sprayed on the surface of the ceramic discs to test the dielectric properties and loss properties of the materials.

[0055] The test results are shown in Table 1. Figure 3 As can be seen from the figure, at room temperature, the dielectric constant of the material 10 4 -10 7 Hz is 21-36, the dielectric constant is stable, and the dielectric loss is 0.035-0.046, which is relatively low.

[0056] The above examples only describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A B-site doped high-entropy strontium titanate ceramic powder, characterized in that, The B-site doped high-entropy strontium titanate ceramic has a chemical formula of: Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3.

2. A method for preparing the B-site doped high-entropy strontium titanate ceramic powder according to claim 1, characterized in that, The method comprises the following steps: SrCO3, TiO2, Ta2O5, In2O3 and ZrO2 powders are weighed according to stoichiometric ratio of chemical formula, mixed and ball milled, a binder is added and stirred uniformly to obtain a ceramic slurry; then, granulation, sintering and sieving are performed to obtain the B-site doped high-entropy strontium titanate powder.

3. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, In the process of the mixed ball milling, anhydrous ethanol and zirconium oxide small balls are used as the ball milling medium, and the mass ratio of the anhydrous ethanol, the zirconium oxide small balls and the raw materials is (4-5):(4-5):1; wherein, the ball milling speed is 300-400 rpm, and the ball milling time is 12-24 hours.

4. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, The binder is gum arabic, and the mass ratio of the binder and the ceramic slurry is (4-5):

100.

5. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, The granulation is performed in a high-speed centrifugal spray drying tower; the inlet air temperature of the drying tower is 200-250 DEG C, the outlet air temperature of the drying tower is 80-120 DEG C, and the atomization speed of the high-speed centrifugal spray drying tower during the granulation is 15600-18000 rpm.

6. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, The sintering condition is that the temperature is increased from room temperature to 1350-1400 DEG C at a temperature increasing rate of 6 DEG C / min, and then the temperature is kept for 3-4 hours, and then the temperature is cooled to room temperature in the furnace.

7. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, The sieving is sieving through an 80-100 mesh sieve.

8. The method for preparing B-site doped high-entropy strontium titanate ceramic powder according to claim 2, characterized in that, The method comprises the following steps: (1) stoichiometric ratio of Sr(Zr 0.25 Ti 0.25 In 0.25 Ta 0.25 )O3, SrCO3, TiO2, Ta2O5, In2O3 and ZrO2 powders are weighed; the powders are put into a ball mill and ball-mixed for 12 hours at a mass ratio of zirconia balls, anhydrous ethanol and raw material powders of 5:5:1 and a rotation speed of 300 rpm to obtain a ceramic slurry; then, gum arabic is added to the obtained ceramic slurry for stirring for 30 minutes at a mass ratio of gum arabic to ceramic slurry of 5:100 to obtain a stirred ceramic slurry; (2) the stirred ceramic slurry obtained in step (1) is placed in a high-speed centrifugal spray drying tower for granulation, the inlet air temperature of the drying tower is 220 DEG C, the outlet air temperature of the drying tower is 110 DEG C, the atomization speed of the high-speed centrifugal spray drying tower during the granulation is 18000 rpm, and then a ceramic particle is obtained; (3) the ceramic particle obtained in step (2) is placed in a crucible, the crucible is placed in a muffle furnace, the temperature is increased to 1350-1400 DEG C at a temperature increasing rate of 6 DEG C / min, the temperature is kept for 3-4 hours in the muffle furnace, and then the temperature is cooled to room temperature in the furnace, and then the sintered powder is sieved through an 80-100 mesh sieve to obtain a B-site doped high-entropy ceramic powder.

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