Rare earth co-doped multi-titanium barium ceramic material for microwave dielectric as well as preparation method and application thereof

Abstract

The invention discloses a rare earth co-doped multi-titanium barium ceramic material for a microwave medium as well as a preparation method and an application of the rare earth co-doped multi-titanium barium ceramic material. The composition expression of the rare earth co-doped multi-titanium barium ceramic material for the microwave medium is (1-y-z) [(1-x) BaO-xTiO2]-yLn2O3-zBi2O3, Ln is selected from at least two of La, Sm, Gd and Y, and x, y and z are molar percentages and meet the following conditions: 74% < = x < = 81%, 1% < = y < = 9.9%, and 0.1% < = z < = 1%. The microwave dielectric ceramic material can maintain the following microwave properties under the sintering condition of 1250-1350 DEG C: epsilon r = 50 + / -1, Qf is greater than or equal to 15,000 GHz, the temperature coefficient of resonance frequency tau f is adjustable and meets the requirement within + / -15 ppm / DEG C, the technical requirements of base station isolators can be met, and the microwave dielectric ceramic material has important industrial application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave dielectric materials, and in particular, relates to a rare earth co-doped multi-titanium-barium ceramic material for microwave dielectrics, a preparation method and an application thereof. Background Art

[0002] With the continuous construction and optimization of 5G networks, base stations will have higher and higher performance requirements for isolators, and the requirements for microwave dielectric materials that meet their needs will also be further improved. In the future, isolators will develop in the direction of higher isolation, lower insertion loss, and wider operating frequency range. At the same time, with the continuous emergence of new materials and new technologies, the design and manufacture of isolators will continue to innovate to meet the needs of base station systems for high-performance and high-reliability isolators. Microwave dielectric ceramic materials are widely used in the field of modern communications due to their low loss and high temperature stability. They are key materials for important components such as resonators, filters, and dielectric waveguide circuits. Therefore, in order to promote the development of isolators and the construction of 5G networks, it is of great significance to develop a type of microwave dielectric ceramic materials with higher dielectric constants, higher quality factors, and lower sintering temperatures.

[0003] The multi-titanium-barium system has attracted extensive attention due to its excellent microwave dielectric properties. At present, the research on multi-titanium-barium system ceramics is mainly focused on BaTi4O9, which is a single type, and the overall performance of the material, including dielectric constant, resonant frequency temperature coefficient, sintering temperature and other properties, still cannot meet technical requirements and production needs. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric, a preparation method and an application thereof; the microwave dielectric ceramic material can maintain the following microwave properties under the sintering condition of 1250-1350°C: ε r =50±1, Qf≥15000GHz, resonant frequency temperature coefficient τ f It is adjustable and meets the requirements within ±15ppm / ℃, which can meet the technical requirements of base station isolators and has important industrial application value.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0006] On the one hand, the present invention provides a rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric, whose composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, wherein Ln is selected from at least two of La, Sm, Gd, and Y, wherein x, y, and z are molar percentages and satisfy the following conditions: 74%≤x≤81%, 1%≤y≤9.9%, and 0.1%≤z≤1%.

[0007] Preferably, Ln is selected from Sm and Y, and Sm and Y are co-doped in an equal molar ratio.

[0008] Furthermore, the dielectric constant ε of the microwave dielectric ceramic material is r is 49~51, the quality factor Qf value is greater than 15000GHz, and the resonant frequency temperature coefficient τ f The absolute value is below 15ppm / ℃.

[0009] Another aspect of the present invention provides a method for preparing a rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric, comprising the following steps:

[0010] 1) BaCO3, TiO2, Ln2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, the weighed materials are fully mixed and then ball-milled, and after ball-milling, they are dried, sieved, put into a corundum crucible, and then pre-calcined at a temperature to obtain a powder substrate;

[0011] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0012] 3) The granular material screened in step 2) is pressed into shape, and finally subjected to binder removal and sintering to obtain the rare earth co-doped multi-titanium-barium ceramic material for microwave medium.

[0013] Furthermore, the temperature of the pre-burning in step 1) is 800-1000° C., and the pre-burning time is 2-5 hours.

[0014] Furthermore, the granulation in step 2) is to mix the dried powder with a binder and then make micron-sized spherical particles; the binder used in the granulation is selected from at least one of polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution and methyl cellulose.

[0015] Furthermore, in step 3), the granular material is pressed into a cylinder with a diameter of 10 mm and a height of 6 mm.

[0016] Furthermore, the debinding process in step 3) is carried out at 600° C. for 2 hours.

[0017] Furthermore, the sintering process in step 3) is performed at 1250-1350° C. for 3-7 hours.

[0018] The invention also provides the application of the rare earth co-doped multi-titanium-barium ceramic material for microwave medium in a base station isolator.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention changes Ti4+ Microwave dielectric multi-titanium-barium ceramics with a variety of crystal phase structures were prepared with a molar fraction of , and a certain proportion of rare earth elements were added on this basis. The dielectric constant of the ceramic material can be improved without changing the material structure, and the resonant frequency temperature coefficient can reach the requirement of near-zero adjustable.

[0021] The present invention improves the overall performance of the multi-titanium-barium ceramic and promotes the application progress of the multi-titanium-barium ceramic as a microwave dielectric material.

[0022] The rare earth co-doped multi-titanium-barium ceramic for microwave medium of the present invention can maintain the following microwave properties under the sintering condition of 1250-1350° C.: ε r =50±1, Qf≥15000GHz, resonant frequency temperature coefficient τ f It is adjustable and meets the requirements within ±15ppm / ℃, which can meet the needs of base station isolators to isolate load power reflection and protect signal sources, and is of great significance to promoting the development of 5G communication technology.

[0023] The rare earth co-doped multi-titanium-barium ceramic for microwave dielectric of the present invention has uniform grain size less than 1000nm. The small and uniform grain size improves the densification degree of the material, helps to reduce the dielectric loss of the microwave dielectric material, and prolongs the service life of the isolator. DETAILED DESCRIPTION

[0024] The technical solutions in the present invention will be described clearly and completely below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides a rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric, whose composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, wherein Ln is selected from at least two of La, Sm, Gd, and Y, wherein x, y, and z are molar percentages and satisfy the following conditions: 74%≤x≤81%, 1%≤y≤9.9%, and 0.1%≤z≤1%.

[0026] The dielectric constant ε of the microwave dielectric ceramic material r is 49~51, the quality factor Qf value is greater than 15000GHz, and the resonant frequency temperature coefficient τ f The absolute value is below 15ppm / ℃.

[0027] The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium comprises the following steps:

[0028] 1) BaCO3, TiO2, Ln2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, the weighed materials are fully mixed and then ball-milled, and after ball-milling, they are dried, sieved, and placed in a corundum crucible, and then pre-calcined at a temperature of 800 to 1000° C. for 2 to 5 hours to obtain a powder substrate;

[0029] 2) ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling; wherein the granulation is to mix the dried powder with a binder and then make micron-sized spherical particles; the binder used in the granulation is selected from at least one of polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution and methyl cellulose;

[0030] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and finally subjected to debinding and sintering. The debinding process is to keep the temperature at 600° C. for 2 hours, and the sintering process is to sinter at 1250° C. to 1350° C. for 3 to 7 hours, and finally the rare earth co-doped multi-titanium-barium ceramic material for microwave medium is obtained.

[0031] The microwave dielectric rare earth co-doped multi-titanium-barium ceramic material can be applied to base station isolators.

[0032] Example 1

[0033] The microwave medium of Example 1 is a rare earth co-doped multi-titanium-barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is Sm and Y, x, y, z are molar percentages, and satisfy the following conditions: x=74%, y=9%, z=1%.

[0034] The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium comprises the following steps:

[0035] 1) BaCO3, TiO2, Sm2O3, Y2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, wherein the rare earth elements are co-doped in an equal molar ratio; the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, and placed in a corundum crucible, and then pre-calcined at a temperature of 800° C. for 5 hours to obtain a powder substrate;

[0036] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0037] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1260° C. for 7 h to obtain the rare earth co-doped multi-titanium-barium ceramic material for microwave medium.

[0038] Example 2

[0039] The microwave medium of Example 2 is a rare earth co-doped multi-titanium-barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is Sm and Gd, x, y, z are molar percentages, and satisfy the following conditions: x=77%, y=6%, z=1%.

[0040] The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium comprises the following steps:

[0041] 1) BaCO3, TiO2, Sm2O3, Gd2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, wherein the rare earth elements are co-doped in an equal molar ratio; the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, and placed in a corundum crucible, and then pre-calcined at a temperature of 900° C. for 4 hours to obtain a powder substrate;

[0042] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0043] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1280° C. for 6 h to obtain the rare earth co-doped multi-titanium-barium ceramic material for microwave medium.

[0044] Example 3

[0045] The microwave medium of Example 3 is a rare earth co-doped multi-titanium-barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is La and Sm, x, y, z are molar percentages, and satisfy the following conditions: x=81%, y=3%, z=0.6%.

[0046] The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium comprises the following steps:

[0047] 1) BaCO3, TiO2, La2O3, Sm2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, wherein the rare earth elements are co-doped in an equal molar ratio; the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, and placed in a corundum crucible, and then pre-calcined at a temperature of 850° C. for 4.5 hours to obtain a powder substrate;

[0048] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0049] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1310° C. for 4.5 h to obtain the rare earth co-doped multi-titanium-barium ceramic material for the microwave medium.

[0050] Example 4

[0051] The microwave medium of Example 4 is a rare earth co-doped multi-titanium barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is La and Gd, x, y, z are molar percentages, and satisfy the following conditions: x=78%, y=9%, z=0.6%.

[0052] The preparation method of the rare earth co-doped multi-titanium-barium ceramic material for microwave medium in Example 4 is different from that in Example 1 in that the weighed rare earth element oxides are La2O3 and Gd2O3.

[0053] Example 5

[0054] The microwave medium of Example 5 is a rare earth co-doped multi-titanium-barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is La and Y, x, y, z are molar percentages, and satisfy the following conditions: x=75%, y=6%, z=0.3%.

[0055] The preparation method of the rare earth co-doped multi-titanium-barium ceramic material for microwave medium in Example 5 is different from that in Example 2 in that the weighed rare earth element oxides are La2O3 and Y2O3.

[0056] Example 6

[0057] The microwave medium of Example 6 is a rare earth co-doped multi-titanium barium ceramic material, and its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is Gd and Y, x, y, z are molar percentages, and satisfy the following conditions: x=79%, y=3%, z=0.3%.

[0058] The preparation method of the rare earth co-doped multi-titanium-barium ceramic material for microwave medium in Example 6 is different from that in Example 3 in that the weighed rare earth element oxides are Gd2O3 and Y2O3.

[0059] Comparative Example 1

[0060] The microwave dielectric ceramic material of Comparative Example 1 has a composition expression of (1-x)BaO-xTiO2, wherein x is a molar percentage and satisfies the following condition: x=80%.

[0061] The method for preparing the microwave dielectric ceramic material comprises the following steps:

[0062] 1) BaCO3 and TiO2 are weighed respectively according to the molar percentage of each element in the composition expression, the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, put into a corundum crucible, and then pre-calcined at a temperature of 900° C. for 4 hours to obtain a powder substrate;

[0063] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0064] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1340° C. for 3.5 h to obtain the microwave dielectric ceramic material.

[0065] Comparative Example 2

[0066] The composition expression of the microwave dielectric ceramic material of Comparative Example 2 is (1-y)[(1-x)BaO-xTiO2]-yLn2O3, wherein Ln is La and Y, x and y are molar percentages, and satisfy the following conditions: x=75%, y=9%.

[0067] The method for preparing the microwave dielectric ceramic material comprises the following steps:

[0068] 1) BaCO3, TiO2, La2O3, and Y2O3 are weighed respectively according to the molar percentage of each element in the composition expression, wherein the rare earth elements are co-doped in an equal molar ratio; the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, and placed in a corundum crucible, and then pre-calcined at 950° C. for 3.5 hours to obtain a powder substrate;

[0069] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0070] 3) The sieved granules in step 2) are pressed into cylinders with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1320° C. for 4 h to obtain the microwave dielectric ceramic material.

[0071] Comparative Example 3

[0072] The microwave dielectric ceramic material of Comparative Example 3 has a composition expression of (1-z)[(1-x)BaO-xTiO2]-zBi2O3, wherein x and z are molar percentages and satisfy the following conditions: x=78%, z=1%.

[0073] 1) BaCO3, TiO2, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, the weighed materials are mixed thoroughly and then ball-milled, and after ball-milling, they are dried, sieved, and put into a corundum crucible, and then pre-calcined at a temperature of 970° C. for 3 h to obtain a powder substrate;

[0074] 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling;

[0075] 3) The sieved granules in step 2) are pressed into a cylinder with a diameter of 10 mm and a height of 6 mm, and are first sintered at 600° C. for 2 h to remove binder, and then sintered at 1280° C. for 5.5 h to obtain the microwave dielectric ceramic material.

[0076] Performance Testing

[0077] The microwave dielectric properties of microwave dielectric ceramics tested using a microwave network analyzer are shown in Table 1.

[0078] Table 1 Parameter values ​​of the embodiments and comparative examples and microwave dielectric properties of microwave dielectric ceramics

[0079]

[0080] It can be seen from Table 1 that, compared with the microwave dielectric ceramic materials of Comparative Examples 1-3, the microwave dielectric ceramic materials prepared in Examples 1-6 of the present invention can maintain the following microwave properties under the sintering conditions of 1250-1350° C.: ε r =50±1, Qf>15000GHz, resonant frequency temperature coefficient τ fThe absolute value is less than 15ppm / ℃. In particular, Sm and Y co-doped multi-titanium barium ceramic materials have the best microwave dielectric properties, which can meet the needs of base station isolators to isolate load power reflection and protect signal sources, and have important industrial value.

[0081] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any modifications or equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric, characterized in that: Its composition expression is (1-yz)[(1-x)BaO-xTiO2]-yLn2O3-zBi2O3, where Ln is selected from at least two of La, Sm, Gd, and Y, where x, y, and z are molar percentages and satisfy the following conditions: 74%≤x≤81%, 1%≤y≤9.9%, and 0.1%≤z≤1%.

2. The rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric according to claim 1, characterized in that: Ln is selected from Sm and Y, and Sm and Y are co-doped in an equal molar ratio.

3. The rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric according to claim 1, characterized in that: The dielectric constant ε of the microwave dielectric ceramic material r is 49~51, the quality factor Qf value is greater than 15000GHz, and the resonant frequency temperature coefficient τ f The absolute value is below 15ppm / ℃.

4. A method for preparing a rare earth co-doped multi-titanium-barium ceramic material for microwave medium as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: 1) BaCO3, TiO2, Ln2O3, and Bi2O3 are weighed respectively according to the molar percentage of each element in the composition expression, the weighed materials are fully mixed and then ball-milled, and after ball-milling, they are dried, sieved, put into a corundum crucible, and then pre-calcined at a temperature to obtain a powder substrate; 2) fully ball-milling the powder substrate obtained in step 1), drying, granulating and sieving after ball-milling; 3) The granular material screened in step 2) is pressed into shape, and finally subjected to binder removal and sintering to obtain the rare earth co-doped multi-titanium-barium ceramic material for microwave medium.

5. The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium according to claim 4, characterized in that: The temperature of the pre-burning in step 1) is 800-1000° C., and the pre-burning time is 2-5 hours.

6. The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium according to claim 4, characterized in that: The granulation described in step 2) is to mix the dried powder with a binder and then make micron-sized spherical particles; the binder used in the granulation is selected from at least one of polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution and methyl cellulose.

7. The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium according to claim 4, characterized in that: In step 3), the granules are pressed into cylinders with a diameter of 10 mm and a height of 6 mm.

8. The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium according to claim 4, characterized in that: The debinding process in step 3) is carried out at 600°C for 2 hours.

9. The method for preparing the rare earth co-doped multi-titanium-barium ceramic material for microwave medium according to claim 4, characterized in that: The sintering process in step 3) is sintering at 1250-1350° C. for 3-7 hours.

10. Use of the rare earth co-doped multi-titanium-barium ceramic material for microwave dielectric as claimed in any one of claims 1 to 3 in a base station isolator.

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