B-site doped silver niobate high-entropy ceramic and preparation method thereof

Abstract

The invention belongs to the technical field of high-entropy ceramic materials, and particularly relates to B-site doped silver niobate high-entropy ceramic and a preparation method thereof. The chemical general formula of the B-site doped silver niobate high-entropy ceramic is Ag (Nb0. 25Ta0. 25V0. 25Mo0. 25) O3. The preparation method comprises the following steps: weighing raw materials Ag2O, Nb2O5, Ta2O5, V2O5 and MoO3 according to the chemical general formula; carrying out first wet ball milling on the raw materials, and then carrying out first drying and calcining to obtain high-entropy ceramic powder; and carrying out second wet ball milling on the high-entropy ceramic powder, and then carrying out second drying, grinding, compression molding and sintering to obtain the high-entropy ceramic material. The prepared Ag (Nb0. 25Ta0. 25V0. 25Mo0. 25) O3 high-entropy ceramic has the advantages that the dielectric constant reaches 314 at about 1kHz, the loss is lower than 0.05, the dielectric constant is higher, and the dielectric loss is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of high entropy ceramic materials, and more specifically relates to a B-site doped silver niobate high entropy ceramic and a preparation method thereof. Background Art

[0002] High entropy ceramic materials are multi-principal component solid solution ceramics formed by doping five or more elements in equal proportions. With the deepening of research in recent years, single-phase solid solution ceramics formed by doping four principal components in equal proportions can also be called high entropy ceramics.

[0003] In the field of dielectric ceramics, the application of traditional lead-based ceramics has been greatly affected by pollution problems. In order to cope with air pollution, the development of lead-free ceramics has become a new direction. Silver niobate ceramics have become a research hotspot for dielectric energy storage ceramics because they are clean and pollution-free. Previously, the modification of silver niobate was mainly to dope elements at the A position or at the B position, and there was also dual doping at the A and B positions.

[0004] At present, there has been no research or report on the design of high entropy of silver niobate. How to design high entropy of B-site of silver niobate and dope four or five suitable elements in equal molar ratio into the B-site lattice of silver niobate to cause lattice distortion effect of silver niobate and increase its disorder, so as to further improve the dielectric properties of silver niobate has become a difficult problem that technicians in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a B-site doped silver niobate high entropy ceramic and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a B-doped silver niobate high entropy ceramic, wherein the chemical formula of the B-doped silver niobate high entropy ceramic is Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3.

[0008] The second technical solution of the present invention is to provide a method for preparing B-site doped silver niobate high entropy ceramics, the steps comprising:

[0009] The raw materials Ag2O, Nb2O5, Ta2O5, V2O5 and MoO3 are weighed according to the chemical formula of the B-site doped silver niobate high entropy ceramics;

[0010] The raw material is subjected to a first wet ball milling, followed by a first drying and calcining to obtain a high entropy ceramic powder;

[0011] The high entropy ceramic powder is subjected to a second wet ball milling, followed by a second drying, grinding, pressing and sintering to obtain the B-site doped silver niobate high entropy ceramic.

[0012] Furthermore, the rotation speed of the first wet ball milling is 300 rpm, the time is 12-24 hours, and the ball milling media are ethanol and zirconia balls, wherein the mass ratio of the zirconia balls, the raw materials and the ethanol is 2:1:2.

[0013] Furthermore, the first drying is carried out at a temperature of 80-100° C. and for a time of 12-24 hours.

[0014] Furthermore, the calcination temperature is 780-850° C., the time is 2-3 hours, and the calcination atmosphere is an oxygen atmosphere.

[0015] Furthermore, the rotation speed of the second wet ball milling is 300 rpm, the time is 12-24 hours, and the ball milling media are ethanol and zirconia balls, wherein the mass ratio of the zirconia balls, high entropy ceramic powder and ethanol is 2:1:2.

[0016] Furthermore, the second drying temperature is 80-100° C. and the time is 12-24 hours.

[0017] Furthermore, the grinding time is 30-50 min.

[0018] Furthermore, the compression molding pressure is 150-240 MPa, and the holding time is 5-15 min.

[0019] Furthermore, the sintering temperature is 1050-1100° C., the holding time is 3-4 hours, and the sintering atmosphere is an oxygen atmosphere.

[0020] The present invention discloses the following technical effects:

[0021] The method for preparing the B-site doped silver niobate high entropy ceramics has simple steps and processes, and has the characteristics of low production cost, high efficiency and the like.

[0022] The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 high entropy ceramics do not require the addition of any binders or sintering aids.

[0023] The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 high entropy ceramics have a dielectric constant of 314 at around 1kHz and a loss of less than 0.05. The dielectric constant is high and the dielectric loss is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )XRD pattern of O3;

[0026] Figure 2 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 ) Dielectric constant of O3 at frequencies from 1kHz to 1MHz;

[0027] Figure 3 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 ) Dielectric loss of O3 at frequencies from 1kHz to 1MHz. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products; the "room temperature" and "normal temperature" involved are both 20-30° C. unless otherwise specified.

[0034] Example 1

[0035] The preparation method of B-doped silver niobate high entropy ceramics comprises the following steps:

[0036] S1, according to the chemical formula Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 weigh Ag2O, Nb2O5, Ta2O5, V2O5, MoO3 powders as raw materials and set aside;

[0037] S2, putting the raw materials into a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconium oxide ball: raw material: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, then putting the ball-milled slurry into an oven, drying it at 80°C for 12 hours, and then putting it into a tubular furnace for calcination at 800°C, the calcination environment is an oxygen atmosphere, and the heat preservation time is 2 hours to obtain a high entropy ceramic powder;

[0038] S3, placing the high entropy ceramic powder in a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconia ball: high entropy ceramic powder: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, and then the ball-milled slurry is placed in an oven and dried at 80° C. for 12 hours. After drying, it is ground in a grinding jar for 30 minutes, and then pressed into a ceramic green body with a diameter of 10 mm under a uniaxial pressure of 150 MPa, and the holding time is 10 minutes;

[0039] S4. Place the ceramic green body in a boat-shaped crucible (a layer of ceramic powder with the same composition is spread on the bottom of the ceramic green body to prevent adhesion), heat it to 1050°C at a heating rate of 6°C / min, keep it warm for 3 hours in an oxygen atmosphere, and cool it to room temperature with the furnace to obtain B-site doped silver niobate high entropy ceramics (Ag(Nb 0.25 Ta 0.25 V 0.25 Mo0.25 )O3).

[0040] Example 2

[0041] The preparation method of B-doped silver niobate high entropy ceramics comprises the following steps:

[0042] S1, according to the chemical formula Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 weigh Ag2O, Nb2O5, Ta2O5, V2O5, MoO3 powders as raw materials and set aside;

[0043] S2, putting the raw materials into a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconium oxide ball: raw material: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, then putting the ball-milled slurry into an oven, drying it at 80°C for 12 hours, and then putting it into a tubular furnace for calcination at 800°C under the condition of oxygen atmosphere, and the heat preservation time is 2.5 hours to obtain high entropy ceramic powder;

[0044] S3, placing the high entropy ceramic powder in a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconia ball: high entropy ceramic powder: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, and then the ball-milled slurry is placed in an oven and dried at 90° C. for 12 hours. After drying, it is ground in a grinding jar for 30 minutes, and then pressed into a ceramic green body with a diameter of 10 mm under a uniaxial pressure of 150 MPa, and the holding time is 8 minutes;

[0045] S4. Place the ceramic green body in a boat-shaped crucible (a layer of ceramic powder with the same composition is spread on the bottom of the ceramic green body to prevent adhesion), heat it to 1060°C at a heating rate of 6°C / min, keep it warm for 3.5 hours in an oxygen atmosphere, and cool it to room temperature with the furnace to obtain B-doped silver niobate high entropy ceramics (Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3).

[0046] Example 3

[0047] The preparation method of B-doped silver niobate high entropy ceramics comprises the following steps:

[0048] S1, according to the chemical formula Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 weigh Ag2O, Nb2O5, Ta2O5, V2O5, MoO3 powders as raw materials and set aside;

[0049] S2, putting the raw materials into a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconium oxide ball: raw material: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, then putting the ball-milled slurry into an oven, drying it at 80°C for 12 hours, and then putting it into a tubular furnace for calcination at 830°C, the calcination environment is an oxygen atmosphere, and the heat preservation time is 3 hours to obtain a high entropy ceramic powder;

[0050] S3, placing the high entropy ceramic powder in a ball mill for wet ball milling and mixing, ball milling for 12 hours at a mass ratio of zirconia ball: high entropy ceramic powder: anhydrous ethanol = 2:1:2, and the ball milling speed is 300 rpm, then the ball-milled slurry is placed in an oven, dried at 100° C. for 24 hours, and then ground in a grinding jar for 30 minutes after drying, and then pressed into a ceramic green body with a diameter of 10 mm under a uniaxial pressure of 150 MPa, and the holding time is 13 minutes;

[0051] S4. Place the ceramic green body in a boat-shaped crucible (a layer of ceramic powder with the same composition is spread on the bottom of the ceramic green body to prevent adhesion), heat it to 1070°C at a heating rate of 6°C / min, keep it warm for 4 hours in an oxygen atmosphere, and cool it to room temperature with the furnace to obtain B-site doped silver niobate high entropy ceramics (Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3).

[0052] Effect example

[0053] Figure 1 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3, it can be seen from the figure that Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 is a silver niobate phase structure and has no other phase structure.

[0054] Figure 2 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 ) Dielectric constant of O3 at frequencies from 1kHz to 1MHz; Figure 3 The Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3 dielectric loss under the condition of 1kHz to 1MHz frequency. Figure 2-Figure 3 It can be seen that the dielectric constant of the ceramic is stable. Under the test from 1kHz to 1MHz, the dielectric constant decreases from 314 to 200. The dielectric constant is stable and the dielectric loss is between 0.028 and 0.049.

[0055] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0056] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A B-site doped silver niobate high entropy ceramic, characterized in that: The chemical formula of the B-site doped silver niobate high entropy ceramic is Ag(Nb 0.25 Ta 0.25 V 0.25 Mo 0.25 )O3.

2. A method for preparing B-doped silver niobate high entropy ceramics, characterized in that the steps include: Weigh the raw materials Ag2O, Nb2O5, Ta2O5, V2O5 and MoO3 according to the chemical general formula of the B-site doped silver niobate high entropy ceramic according to claim 1; The raw material is subjected to a first wet ball milling, followed by a first drying and calcining to obtain a high entropy ceramic powder; The high entropy ceramic powder is subjected to a second wet ball milling, followed by a second drying, grinding, pressing and sintering to obtain the B-site doped silver niobate high entropy ceramic.

3. The preparation method according to claim 2, characterized in that: The rotation speed of the first wet ball milling is 300 rpm, the time is 12-24 hours, and the ball milling media are ethanol and zirconia balls, wherein the mass ratio of the zirconia balls, the raw materials and the ethanol is 2:1:

2.

4. The preparation method according to claim 2, characterized in that: The first drying is carried out at a temperature of 80-100° C. and for a time of 12-24 hours.

5. The preparation method according to claim 2, characterized in that: The calcination temperature is 780-850° C. and the calcination time is 2-3 hours.

6. The preparation method according to claim 2, characterized in that: The rotation speed of the second wet ball milling is 300 rpm, the time is 12-24 hours, and the ball milling media are ethanol and zirconia balls, wherein the mass ratio of the zirconia balls, high entropy ceramic powder and ethanol is 2:1:

2.

7. The preparation method according to claim 2, characterized in that: The second drying process is carried out at a temperature of 80-100° C. and for a time of 12-24 hours.

8. The preparation method according to claim 2, characterized in that: The grinding time is 30-50 min.

9. The preparation method according to claim 2, characterized in that: The compression molding pressure is 150-240 MPa, and the holding time is 5-15 min.

10. The preparation method according to claim 2, characterized in that: The sintering temperature is 1050-1100° C., and the heat preservation time is 3-4 hours.

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