CN116803947A - Low-dielectric-constant titanate microwave dielectric ceramic and preparation method and application thereof - Google Patents

Low-dielectric-constant titanate microwave dielectric ceramic and preparation method and application thereof Download PDF

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CN116803947A
CN116803947A CN202310815696.2A CN202310815696A CN116803947A CN 116803947 A CN116803947 A CN 116803947A CN 202310815696 A CN202310815696 A CN 202310815696A CN 116803947 A CN116803947 A CN 116803947A
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李纯纯
朱国斌
陈德钦
尹长志
朱肖伟
熊思宇
王政锋
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Guilin University of Technology
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Guilin University of Technology
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Abstract

The application provides a low-dielectric-constant titanate microwave dielectric ceramic, and a preparation method and application thereof, and belongs to the technical field of dielectric ceramic materials. The chemical composition of the low dielectric constant titanate microwave dielectric ceramic of the application is Re 2 TiO 5 Wherein Re is Nd, sm, eu or Gd. The Nd is precisely synthesized respectively by the pre-sintering process of the design raw materials 2 TiO 5 、Sm 2 TiO 5 、Eu 2 TiO 5 And Gd 2 TiO 5 Single-phase powder is granulated by adding binder before compression molding, and hasThe ceramic material with excellent microwave dielectric property is obtained by optimizing sintering system and promoting ceramic grain growth, the dielectric constant reaches 13.4-15.7, the Q multiplied by f value reaches 8696-12698GHz, and the ceramic material can be widely used for manufacturing microwave devices such as various dielectric substrates, resonators, filters and the like and has great application value in industry.

Description

Low-dielectric-constant titanate microwave dielectric ceramic and preparation method and application thereof
Technical Field
The application belongs to the technical field of dielectric ceramic materials, and particularly relates to a low-dielectric-constant titanate microwave dielectric ceramic, and a preparation method and application thereof.
Background
The microwave dielectric ceramic (MWDC) is a functional ceramic material which is used as a dielectric material in a microwave frequency band (300 MHz-300 GHz) circuit and can perform one or more functions, is a key material of microwave components such as resonators, filters, dielectric wave guide loops and the like widely used in modern communication, and has wide application in the aspects of radars, automobile phones, cordless phones, GPS antennas and the like.
With the advent of the 5G and 6G ages, wireless communication is gradually turned to millimeter wave transmission, and demands for high frequency, integration, high reliability and low latency are made on a communication system, so that signal delay and bandwidth problems are focused. According to the positive correlation between signal delay and dielectric constantWherein t is d 、l c And c represents the signal delay time, transmission distance, and speed of light, respectively), low dielectric constant (ε r ) The delay time of the transmission of electromagnetic wave signals in the medium can be reduced; at the same time, it is required that the material has a high quality factor (Q×f) and a near-zero resonant frequency temperature coefficient (τ) f ) To achieve low loss and thermal stability of the microwave device. At present, some low dielectric constant inorganic compounds have been reported, most of which are based on aluminates, borates, silicates, and the like. Crystals of these candidatesThe bulk structure is composed of tetrahedral building blocks (i.e. AlO 4 ，BO 4 ，SiO 4 Etc.), the tetrahedral gaps are small from the standpoint of crystallography, the space provided for cationic oscillation is limited, and the ion/electron polarizability is low, so that the above-mentioned inorganic compound has a low dielectric constant. In contrast, those titanate compounds constructed by oxygen octahedral co-roof linkages generally have a high dielectric constant, such as CaTiO 3 (ε r ～90)，SrTiO 3 (ε r 290) cannot meet the requirements of microwave equipment. Therefore, the application provides a novel low-dielectric-constant titanate microwave dielectric ceramic, and a preparation method and application thereof.
Disclosure of Invention
In order to solve the technical problems, the application provides a low-dielectric-constant titanate microwave dielectric ceramic, and a preparation method and application thereof.
In order to achieve the above purpose, the present application provides the following technical solutions:
one of the technical schemes of the application is as follows:
a low-dielectric-constant titanate microwave dielectric ceramic has the chemical composition Re 2 TiO 5 Wherein Re is Nd, sm, eu or Gd, the low-dielectric-constant titanate microwave dielectric ceramic has an orthogonal structure (the X-ray diffraction peak of the ceramic sample can be equal to that of each Re 2 TiO 5 The PDF card of (c) corresponds exactly). At the quadrature Re 2 TiO 5 In the structure (Pnam space group), all ions occupy the 4cWyckoff position, re is linked to 7O to form [ ReO ] 7 ]Polyhedron, ti is connected with 5O to form [ TiO ] 5 ]Eccentric pyramid, [ ReO ] 7 ]And [ TiO 5 ]The polyhedrons are connected in a common-edge mode. The structure has a limited space for cation oscillation due to cation deviation from the center point of the polyhedron caused by the asymmetry of the coordination polyhedron, namely, the polyhedron gap is provided for Re 2 TiO 5 Ceramics have the characteristic of low dielectric constants.
The second technical scheme of the application is as follows:
a preparation method of low dielectric constant titanate microwave dielectric ceramic comprises the following steps:
(1) Re with purity of 99.9% (weight percent) or more 2 O 3 And TiO 2 According to Re of the original powder of (C) 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, and drying at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture A obtained in the step (1) to obtain powder;
(3) Carrying out wet ball milling on the powder obtained in the step (2) for 6 hours, and drying at 120 ℃ to obtain a mixture B;
(4) Adding a binder into the mixture B obtained in the step (3), granulating, sieving, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) And (3) discharging the adhesive from the green body obtained in the step (4), and sintering to obtain the low-dielectric-constant titanate microwave dielectric ceramic.
Preferably, in the step (1) and the step (3), the medium of the wet ball milling is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, and the rotation direction is changed once every 60 min.
Preferably, in the step (2), the presintering temperature is 950-1050 ℃ and the presintering time is 2-6h.
More preferably, in the step (2), the temperature of the pre-sintering is 1000 ℃ and the time is 4 hours.
Preferably, in the step (4), the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the binder accounts for 3% of the mass of the mixture B.
Preferably, in the step (4), the mixture is sieved by a 60-120 mesh sieve.
Preferably, in the step (5), the temperature of the adhesive discharge is 550 ℃, the time is 6 hours, and the heating rate is 1.5 ℃/min.
Preferably, in the step (5), the sintering is performed in an atmosphere at 1200-1325 ℃ for 4 hours.
Preferably, in the step (5), the glue discharging and sintering are performed in a muffle furnace.
The third technical scheme of the application:
the low-dielectric constant titanate microwave dielectric ceramic is applied to microwave devices.
Compared with the prior art, the application has the following advantages and technical effects:
(1) The Nd is precisely synthesized respectively by the pre-sintering process of the design raw materials 2 TiO 5 、Sm 2 TiO 5 、Eu 2 TiO 5 Or Gd 2 TiO 5 The single-phase powder is granulated by adding a binder before compression molding, which is beneficial to molding, and finally optimizes the sintering system and promotes the growth of ceramic grains, thus obtaining the ceramic material with excellent microwave dielectric property.
(2) Dielectric ceramic material (Re) prepared by the application 2 TiO 5 (re=nd, sm, eu or Gd)) is an orthogonal structure, the dielectric constant of the dielectric constant reaches 13.4-15.7, the quality factor qxf reaches 8696-12698GHz, and the dielectric constant can be widely used for manufacturing microwave devices such as various dielectric substrates, resonators, filters and the like, and has great application value in industry.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 shows a microwave dielectric ceramic Nd prepared in example 1 2 TiO 5 An XRD pattern of (b);
FIG. 2 shows a microwave dielectric ceramic Nd prepared in example 2 2 TiO 5 Wherein a is an XRD pattern and b is an SEM pattern;
FIG. 3 shows a microwave dielectric ceramic Sm prepared in example 3 2 TiO 5 An XRD pattern of (b);
FIG. 4 shows a microwave dielectric ceramic Sm prepared in example 4 2 TiO 5 Wherein a is an XRD pattern and b is an SEM pattern;
FIG. 5 shows a microwave dielectric ceramic Eu prepared in example 5 2 TiO 5 An XRD pattern of (b);
FIG. 6 shows a microwave dielectric ceramic Eu prepared in example 6 2 TiO 5 Wherein a is an XRD pattern and b is an SEM pattern;
FIG. 7 shows a microwave dielectric ceramic Gd prepared in example 7 2 TiO 5 An XRD pattern of (b);
FIG. 8 shows a microwave dielectric ceramic Gd prepared in example 8 2 TiO 5 Wherein a is an XRD pattern and b is an SEM pattern;
FIG. 9 is an XRD pattern of the microwave dielectric ceramics prepared in comparative examples 1 to 4, wherein a is comparative example 1, b is comparative example 2, c is comparative example 3, and d is comparative example 4;
FIG. 10 shows a microwave dielectric ceramic Ho prepared in comparative example 5 2 TiO 5 An XRD pattern of (b);
fig. 11 is an XRD comparison pattern of the microwave dielectric ceramics prepared in example 2, example 4, example 6 and example 8.
Detailed Description
Various exemplary embodiments of the application will now be described in detail, which should not be considered as limiting the application, but rather as more detailed descriptions of certain aspects, features and embodiments of the application.
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 application. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, 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 only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the application described herein without departing from the scope or spirit of the application. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present application. The specification and examples of the present application are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
The application provides a low-dielectric-constant titanate microwave dielectric ceramic, which has the chemical composition Re 2 TiO 5 Wherein Re is Nd, sm, eu or Gd, the low-dielectric-constant titanate microwave dielectric ceramic has an orthogonal structure (the X-ray diffraction peak of the ceramic sample can be equal to that of each Re 2 TiO 5 The PDF card of (c) corresponds exactly). At the quadrature Re 2 TiO 5 In the structure (Pnam space group), all ions occupy the 4c Wyckoff position, re is linked to 7O to form [ ReO ] 7 ]Polyhedron, ti is connected with 5O to form [ TiO ] 5 ]Eccentric pyramid, [ ReO ] 7 ]And [ TiO 5 ]The polyhedrons are connected in a common-edge mode. The structure has a limited space for cation oscillation due to cation deviation from the center point of the polyhedron caused by the asymmetry of the coordination polyhedron, namely, the polyhedron gap is provided for Re 2 TiO 5 Ceramics have the characteristic of low dielectric constants.
The application also provides a preparation method of the low-dielectric-constant titanate microwave dielectric ceramic, and Nd is respectively and accurately synthesized by a design raw material presintering process 2 TiO 5 、Sm 2 TiO 5 、Eu 2 TiO 5 Or Gd 2 TiO 5 The single-phase powder is granulated by adding a binder before compression molding, which is beneficial to molding, and finally optimizes the sintering system to promote the growth of ceramic grains, thus obtaining the ceramic material with excellent microwave dielectric property, and the preparation method comprises the following steps:
(1) Re with purity of 99.9% (weight percent) or more 2 O 3 And TiO 2 According to Re of the original powder of (C) 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, and drying at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture obtained in the step (1) to obtain powder;
(3) Carrying out wet ball milling on the powder obtained in the step (2) for 6 hours, and drying at 120 ℃ to obtain a mixture B;
(4) Adding a binder into the mixture B obtained in the step (3), granulating, sieving, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) And (3) discharging the adhesive from the green body obtained in the step (4), and sintering to obtain the low-dielectric-constant titanate microwave dielectric ceramic.
In the embodiment of the application, in the step (1) and the step (3), the medium of the wet ball milling is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, and the rotation reversing is carried out once every 60 min.
In the embodiment of the application, in the step (2), the presintering temperature is 950-1050 ℃ and the presintering time is 2-6h. More preferably, in the step (2), the temperature of the pre-sintering is 1000 ℃ and the time is 4 hours.
In the embodiment of the present application, in the step (4), the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the binder accounts for 3% of the mass of the mixture B.
In the embodiment of the application, in the step (4), the mixture is sieved by a 60-120 mesh sieve.
In the embodiment of the application, in the step (5), the temperature of the adhesive discharge is 550 ℃, the time is 6 hours, and the heating rate is 1.5 ℃/min.
In the embodiment of the application, in the step (5), the sintering is performed in an atmosphere at 1200-1325 ℃ for 4 hours. The dielectric properties of microwave dielectric ceramics are determined by intrinsic and extrinsic factors, and suitable sintering temperatures can exclude to some extent the effects of extrinsic factors on performance, and it is generally believed that highly densified ceramic samples have optimal dielectric properties, while the presence of microscopic pores can compromise dielectric properties. In the application, re cannot be synthesized at the temperature lower than 1200 DEG C 2 TiO 5 The bulk density of the single-phase ceramic sample synthesized at the temperature of 1200-1325 ℃ is in an ascending trend, and the bulk density of the single-phase ceramic sample higher than 1325 ℃ is in a descending trend, namely, the ceramic sample sintered for 4 hours in the atmosphere at the temperature of 1325 ℃ has the highest densification degree and the best dielectric property.
In the embodiment of the application, in the step (5), the glue discharging and sintering are performed in a muffle furnace.
The raw materials used in the examples of the present application are all commercially available.
The technical scheme of the application is further described by the following examples.
Example 1
(1) Nd with purity of 99.9% (weight percentage) 2 O 3 And TiO 2 According to Nd 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, wherein the ball milling medium is absolute ethyl alcohol, the ball milling speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture obtained in the step (1) for 4 hours at 1000 ℃ to obtain powder;
(3) Adding the powder obtained in the step (2) into a ball milling tank, performing wet ball milling for 6 hours, wherein a ball milling medium is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture B;
(4) Adding a binder (a polyvinyl alcohol solution with the mass concentration of 5 percent and the binder accounting for 3 percent of the mass of the mixture B) into the mixture B obtained in the step (3), granulating, sieving with a 60-120 mesh sieve, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) Discharging glue from the green embryo obtained in the step (4) for 6 hours at 550 ℃, wherein the heating rate is 1.5 ℃/min, and finally sintering for 4 hours in the atmosphere at 1200 ℃ to obtain the low-dielectric-constant titanate microwave dielectric ceramic Nd 2 TiO 5 。
Microwave dielectric ceramic Nd prepared in example 1 2 TiO 5 As can be seen from FIG. 1, the X-ray diffraction peak of the material after sintering at 1200 ℃ can be seen from FIG. 1Nd 2 TiO 5 (PDF: 96-200-2194) calibration, no second phase appears, indicating Nd formation at this temperature 2 TiO 5 A single phase.
Example 2
The difference from example 1 is only that in step (5), sintering is carried out at 1325℃for 4 hours.
Example 2 microwave dielectric ceramic Nd 2 TiO 5 The XRD pattern and SEM pattern of (2) are shown in FIG. 2, wherein a is XRD pattern and b is SEM pattern, and as can be seen from FIG. 2, the X-ray diffraction peak energy of the material after sintering at 1325 ℃ is equal to Nd 2 TiO 5 (PDF: 96-200-2194) corresponds exactly, and it can be found by combining SEM image that sintering at 1325 ℃, nd 2 TiO 5 The ceramic grains are closely arranged, the grain boundary is clear, and no visible air holes are formed.
Example 3
(1) Sm with purity of 99.9% (wt.%) or more 2 O 3 And TiO 2 Raw powder according to Sm 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, wherein the ball milling medium is absolute ethyl alcohol, the ball milling speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture obtained in the step (1) for 4 hours at 1000 ℃ to obtain powder;
(3) Adding the powder obtained in the step (2) into a ball milling tank, performing wet ball milling for 6 hours, wherein a ball milling medium is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture B;
(4) Adding a binder (a polyvinyl alcohol solution with the mass concentration of 5 percent and the binder accounting for 3 percent of the mass of the mixture B) into the mixture B obtained in the step (3), granulating, sieving with a 60-120 mesh sieve, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) Discharging glue from the green embryo obtained in the step (4) for 6 hours at 550 ℃, wherein the heating rate is 1.5 ℃/min, and finally sintering for 4 hours in the atmosphere at 1200 ℃ to obtain the low-dielectric-constant titanate microwave dielectric ceramic Sm 2 TiO 5 。
Examples3 microwave dielectric ceramic Sm prepared by 2 TiO 5 As can be seen from FIG. 3, the X-ray diffraction peak of the material after sintering at 1200 ℃ can be seen from Sm 2 TiO 5 (PDF: 00-022-1306) calibration, no second phase appears, indicating Sm formation at this temperature 2 TiO 5 A single phase.
Example 4
The difference from example 3 is only that in step (5), sintering is carried out at 1325℃for 4 hours.
The microwave dielectric ceramic Sm prepared in example 4 2 TiO 5 The XRD pattern and SEM pattern of (2) are shown in FIG. 4, wherein a is XRD pattern and b is SEM pattern, and as can be seen from FIG. 4, the X-ray diffraction peak energy of the material after sintering at 1325 ℃ is equal to Sm 2 TiO 5 (PDF: 00-022-1306) corresponds completely, and it can be found by combining SEM image that sintering is carried out at 1325 ℃, sm 2 TiO 5 The ceramic grains are closely arranged, the grain boundary is clear, and no visible air holes are formed.
Example 5
(1) Eu with purity of 99.9% (weight percentage) or more 2 O 3 And TiO 2 Eu as raw powder of (C) 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, wherein the ball milling medium is absolute ethyl alcohol, the ball milling speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture obtained in the step (1) for 4 hours at 1000 ℃ to obtain powder;
(3) Adding the powder obtained in the step (2) into a ball milling tank, performing wet ball milling for 6 hours, wherein a ball milling medium is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture B;
(4) Adding a binder (a polyvinyl alcohol solution with the mass concentration of 5 percent and the binder accounting for 3 percent of the mass of the mixture B) into the mixture B obtained in the step (3), granulating, sieving with a 60-120 mesh sieve, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) Draining the green embryo obtained in the step (4) at 550 ℃ for 6 hours, wherein the heating rate is 1.5 ℃/min, and finally at 1200 DEG CSintering for 4 hours in the atmosphere of the (2) to obtain the low-dielectric-constant titanate microwave dielectric ceramic Eu 2 TiO 5 。
Microwave dielectric ceramic Eu prepared in example 5 2 TiO 5 As can be seen from FIG. 5, the XRD pattern of the material after sintering at 1200 ℃ has an X-ray diffraction peak of Eu 2 TiO 5 (PDF: 01-082-1009) no second phase appears, indicating Eu formation at this temperature 2 TiO 5 A single phase.
Example 6
The difference from example 5 is only that in step (5), sintering is carried out at 1325℃for 4 hours.
Microwave dielectric ceramic Eu prepared in example 6 2 TiO 5 The XRD pattern and SEM pattern of (2) are shown in FIG. 6, wherein a is XRD pattern and b is SEM pattern, and it can be seen from FIG. 6 that the material has X-ray diffraction peak energy after sintering at 1325 ℃ and Eu 2 TiO 5 (PDF: 01-082-1009) completely corresponds, and it can be found by combining SEM image that Eu is sintered at 1325 DEG C 2 TiO 5 The ceramic grains are closely arranged, the grain boundary is clear, and no visible air holes are formed.
Example 7
(1) Gd with purity of 99.9% (weight percentage) 2 O 3 And TiO 2 According to Gd 2 TiO 5 Mixing the raw powder, adding the mixture into a ball milling tank, performing wet ball milling for 6 hours, wherein the ball milling medium is absolute ethyl alcohol, the ball milling speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture A;
(2) Presintering the mixture obtained in the step (1) for 4 hours at 1000 ℃ to obtain powder;
(3) Adding the powder obtained in the step (2) into a ball milling tank, performing wet ball milling for 6 hours, wherein a ball milling medium is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, the rotation and the reversing are performed once every 60min, and drying is performed at 120 ℃ to obtain a mixture B;
(4) Adding a binder (a polyvinyl alcohol solution with the mass concentration of 5 percent and the binder accounting for 3 percent of the mass of the mixture B) into the mixture B obtained in the step (3), granulating, sieving with a 60-120 mesh sieve, and pressing into a cylinder by using a powder tablet press to obtain a green body;
(5) Discharging glue from the green embryo obtained in the step (4) for 6 hours at 550 ℃, wherein the heating rate is 1.5 ℃/min, and finally sintering for 4 hours in the atmosphere at 1200 ℃ to obtain the low-dielectric-constant titanate microwave dielectric ceramic Gd 2 TiO 5 。
Microwave dielectric ceramic Gd prepared in example 7 2 TiO 5 As can be seen from FIG. 7, the X-ray diffraction peak of the material after sintering at 1200 ℃ can be seen from Gd 2 TiO 5 (PDF: 00-021-0342) calibration, no second phase appears, indicating Gd formation at this temperature 2 TiO 5 A single phase.
Example 8
The difference from example 7 is only that in step (5), sintering is carried out at 1325℃for 4 hours.
Microwave dielectric ceramic Gd prepared in example 8 2 TiO 5 The XRD pattern and SEM pattern of (2) are shown in FIG. 8, wherein a is XRD pattern and b is SEM pattern, and as can be seen from FIG. 6, the X-ray diffraction peak energy of the material after sintering at 1325 ℃ is compared with Gd 2 TiO 5 (PDF: 00-021-0342) was completely corresponding, and it was found by combining SEM image that sintering was performed at 1325 ℃, gd 2 TiO 5 The ceramic grains are closely arranged, the grain boundary is clear, and no visible air holes are formed.
Comparative example 1
The difference from example 1 is only that in step (5), sintering is carried out at 1050℃for 4 hours.
Comparative example 1 microwave dielectric ceramic Nd 2 TiO 5 The XRD pattern of (a) is shown in FIG. 9 (a), and it can be seen that the phase of the material after sintering at 1050℃is mainly Nd 2 TiO 5 But accompanied by Nd 2 Ti 2 O 7 And Nd 2 O 3 The presence of the impurity phase indicates that the sintering condition can not synthesize Nd 2 TiO 5 A single phase.
Comparative example 2
The difference from example 3 is only that in step (5), sintering is carried out at 1050℃for 4 hours.
Comparative example 2 microwave dielectric ceramic Sm 2 TiO 5 The XRD pattern of (a) is shown in FIG. 9 (b), and it can be seen that the material after sintering at 1050 ℃The material phase is mainly Sm 2 TiO 5 But accompanied by Sm 2 Ti 2 O 7 And Sm 2 O 3 The presence of the impurity phase indicates that the sintering condition can not synthesize Sm 2 TiO 5 A single phase.
Comparative example 3
The difference from example 5 is only that in step (5), sintering is carried out at 1050℃for 4 hours.
Comparative example 3 microwave dielectric ceramic Eu 2 TiO 5 As can be seen from the XRD pattern of FIG. 9 (c), the material phase after sintering at 1050℃is mainly Eu 2 TiO 5 But accompanied by Eu 2 Ti 2 O 7 And Eu 2 O 3 The presence of the impurity phase indicates that the sintering condition can not synthesize Eu 2 TiO 5 A single phase.
Comparative example 4
The difference from example 7 is only that in step (5), sintering is carried out at 1050℃for 4 hours.
Comparative example 4 microwave dielectric ceramic Gd 2 TiO 5 The XRD pattern of (a) is shown in FIG. 9 (d), and it can be seen that the material phase after sintering at 1050℃is mainly Gd 2 TiO 5 But with Gd 2 Ti 2 O 7 And Gd 2 O 3 The existence of hetero-phase indicates that the sintering condition can not synthesize Gd 2 TiO 5 A single phase.
Comparative example 5
The difference from example 1 is that Nd as a raw material in step (1) was obtained 2 O 3 Equal mass substitution to Ho 2 O 3 In step (5), the green body is sintered at 1400 ℃ for 4 hours.
Comparative example 5 microwave dielectric ceramic Ho 2 TiO 5 As can be seen from the XRD pattern of FIG. 10, the diffraction peaks can be seen from Ho 2 TiO 5 (PDF: 00-34-1423) and Ho 2 TiO 5 (PDF: 00-36-1436), i.e. after sintering at 1400 ℃ the phase of the material is Ho 2 TiO 5 Two phases of the hexagonal structure and the cubic structure coexist, and a single phase of the non-orthogonal structure exists.
Example 2, example 4, example 6 and example 8As can be seen from FIG. 11, each X-ray diffraction peak of the four examples above first has a highly similar characteristic, which is also Nd 2 TiO 5 、Sm 2 TiO 5 、Eu 2 TiO 5 And Gd 2 TiO 5 Single phases have the same orthogonal structure providing evidence; next, according to Nd 2 TiO 5 To Gd 2 TiO 5 In the order of (2), it was observed that the X-ray diffraction peak positions exhibited a tendency toward a high angular shift due to the difference in the size of the ion radius of the heptacoordinated (r (Nd 3+ )>r(Sm 3+ )>r(Eu 3+ )>r(Gd 3+ ) Resulting in four Re' s 2 TiO 5 The unit cell parameters of the compounds are different.
Performance testing
The microwave dielectric properties of the microwave dielectric ceramics prepared in examples 1 to 8 were respectively tested using a cylindrical dielectric resonator, and the results are shown in Table 1.
TABLE 1 microwave dielectric Properties of microwave dielectric ceramics
Composition of the composition Sintering temperature (. Degree. C.) ρ(g/cm 3 ) ε r Q×f(GHz)
Example 1 Nd 2 TiO 5 1200 5.5568 15.2 10556
Example 2 Nd 2 TiO 5 1325 5.7746 15.7 12698
Example 3 Sm 2 TiO 5 1200 5.8388 14.1 9078
Example 4 Sm 2 TiO 5 1325 6.0782 14.4 10653
Example 5 Eu 2 TiO 5 1200 5.2986 14.3 8988
Example 6 Eu 2 TiO 5 1325 6.0826 14.6 10210
Example 7 Gd 2 TiO 5 1200 5.3558 13.4 8696
Example 8 Gd 2 TiO 5 1325 6.2888 14.0 9714
As can be seen from Table 1, the dielectric constant of the microwave dielectric ceramic material prepared by the application reaches 13.4-15.7, the Q multiplied by f value of the quality factor reaches 8696-12698GHz, and the microwave dielectric ceramic material can be widely applied to the manufacture of various dielectric substrates, resonators, filters and other microwave devices and has great application value in industry.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (10)

1. Low dielectric constant titanate microwave mediumAn electroceramic, characterized in that the low dielectric constant titanate microwave dielectric ceramic has a chemical composition Re 2 TiO 5 Wherein Re is Nd, sm, eu or Gd.
2. A method for preparing the low dielectric constant titanate microwave dielectric ceramic of claim 1, comprising the steps of:
(1) Re with purity of 99.9% or higher 2 O 3 And TiO 2 According to Re of the original powder of (C) 2 TiO 5 The raw powder is mixed, ball-milled by a wet method and dried to obtain a mixture A;
(2) Presintering the mixture A to obtain powder;
(3) Carrying out wet ball milling on the powder, and drying to obtain a mixture B;
(4) Adding a binder into the mixture B, granulating, sieving, and performing compression molding to obtain a green body;
(5) And discharging the green body, and sintering to obtain the low-dielectric-constant titanate microwave dielectric ceramic.
3. The preparation method according to claim 2, wherein in the step (1) and the step (3), the medium of wet ball milling is absolute ethyl alcohol, the ball milling rotating speed is 300r/min, and the rotation direction is changed every 60 min.
4. The method according to claim 2, wherein in the step (2), the pre-firing is performed at 950-1050 ℃ for 2-6 hours.
5. The method according to claim 4, wherein in the step (2), the pre-firing temperature is 1000 ℃ for 4 hours.
6. The method according to claim 2, wherein in the step (4), the binder is a polyvinyl alcohol solution having a mass concentration of 5%, and the binder accounts for 3% of the mass of the mixture B.
7. The method of claim 2, wherein in step (4), the sieving is through a 60-120 mesh sieve.
8. The method according to claim 2, wherein in the step (5), the temperature of the adhesive discharge is 550 ℃, the time is 6 hours, and the heating rate is 1.5 ℃/min.
9. The method according to claim 2, wherein in the step (5), the sintering is performed in an atmosphere of 1200 to 1325 ℃ for 4 hours.
10. Use of the low dielectric constant titanate microwave dielectric ceramic of claim 1 in a microwave device.
CN202310815696.2A 2023-07-04 2023-07-04 Low-dielectric-constant titanate microwave dielectric ceramic and preparation method and application thereof Pending CN116803947A (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113666745A (en) * 2021-09-27 2021-11-19 桂林理工大学 Microwave dielectric ceramic with ultralow sintering temperature and preparation method thereof

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Publication number Priority date Publication date Assignee Title
CN113666745A (en) * 2021-09-27 2021-11-19 桂林理工大学 Microwave dielectric ceramic with ultralow sintering temperature and preparation method thereof

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ROBERTD.AUGHTERSON等人: "Ion-irradiation resistance of the orthorhombic Ln2TiO5 (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) series", 《JOURNAL OF NUCLEAR MATERIALS》, vol. 467, 21 October 2015 (2015-10-21), pages 683 - 691 *
Y.V. DIDENKO等人: "New Insight on Microwave Dielectrics Thermostability", 《2017 INTERNATIONAL CONFERENCE ON INFORMATION AND TELECOMMUNICATION TECHNOLOGIES AND RADIO ELECTRONICS》, 17 September 2017 (2017-09-17), pages 1 - 4, XP033248127, DOI: 10.1109/UkrMiCo.2017.8095360 *
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