A ceramic with high dielectric constant and low dielectric loss and a method for preparing the same
The preparation of CaCu3Ti4-xNbxO12 ceramics by solid-state reaction method, with the addition of Nb2O5 and control of sintering conditions, solved the problems of high dielectric loss and complex process, and realized the preparation of ceramic materials with large dielectric constant and low dielectric loss, which are suitable for integrated circuit and energy storage fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI'AN POLYTECHNIC UNIVERSITY
- Filing Date
- 2022-01-24
- Publication Date
- 2026-07-31
AI Technical Summary
While existing technologies can reduce the dielectric loss of CaCu3Ti4O12 ceramics, they often result in a significant decrease in dielectric constant or are too complex to achieve large-scale production.
A ceramic material with a large dielectric constant and low dielectric loss was prepared by using a solid-state reaction method combined with pre-firing, debinding and sintering processes, adding Nb2O5 as an additive, and controlling the sintering conditions.
It significantly reduces dielectric loss while maintaining a large dielectric constant, has a simple process that is easy to mass-produce, and has stable dielectric properties, making it suitable for integrated circuit miniaturization and energy storage.
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Figure CN114436643B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical technology, specifically to a ceramic with a large dielectric constant and low dielectric loss, and its preparation method. Background Technology
[0002] CaCu3Ti4O 12 (Abbreviated as CCTO) is a novel electronic ceramic material. At room temperature, the dielectric constant of single-crystal samples is close to 100,000, while that of bulk polycrystalline samples is around 10,000. The dielectric loss is approximately 0.15 over a wide frequency range. Furthermore, the crystal structure of the material remains unchanged within the range of 100K to 400K. CaCu3Ti4O 12 The excellent dielectric properties of CCTO make it a promising material for applications in integrated circuit miniaturization, energy storage, and sensors. However, the high dielectric loss of CCTO itself is a major obstacle to its practical application. Therefore, ensuring the high dielectric constant of CCTO ceramics while reasonably reducing dielectric loss is of great significance for the engineering application of this material.
[0003] Li Jie et al. used cold isostatic pressing in Chinese patent 200710009111.9 to reduce the dielectric loss of CCTO ceramics to 0.026 at room temperature and 1 kHz, but the dielectric constant also dropped to about 3000. Zhao Yanhui (Zhao Yanhui. Study on preparation of calcium copper titanate and dielectric properties by coprecipitation method [D]. Ocean University of China, 2013, 39-48) used coprecipitation method to prepare CCTO ceramics. The dielectric loss was reduced compared with pure CCTO in a wide frequency range at room temperature, and the dielectric constant could still reach 9775. However, the coprecipitation method is complicated, has poor reliability, and is not easy to realize large-scale industrial production.
[0004] Thongbai and his team at Khon Kaen University in Thailand reduced the loss to around 0.02 kHz (10 kHz) by doping Ba ions at the Ca sites in CCTO samples. However, their sample Ca... 0.975 Ba 0.025 Ti4O 12 The dielectric constant of this material is significantly lower than that of pure CCTO (Thongbai P, Vanchangyia S, Swatsitang E, et al. Non-Ohmic and dielectric properties of Ba-doped CaCu3Ti4O). 12In addition, many researchers have used similar doping methods to incorporate various elements into CCTO, such as La ions (Feng LX, Tang XM, Yan YY, et al. Decrease of dielectric loss in CaCu3Ti4O). 12 ceramics by La doping[J],Physics Status Solidi A-Applications and Materials Science,2006,203(4):22-24),Mn ions (Li M,Feteira A,Sinclair DC,et al.Influence ofMn doping on thesemiconducting properties of CaCu3Ti4O 12 These improved methods, such as those mentioned above, all achieve the results of reducing the dielectric loss of CCTO ceramic samples by sacrificing a portion of the dielectric constant.
[0005] The above experiments, while suppressing dielectric loss, resulted in a significant decrease in dielectric constant, or were too complex for large-scale industrial production. This invention, using a traditional solid-state method, prepares CCTO ceramics that not only maintain their large dielectric constant but also significantly reduce dielectric loss. Furthermore, the preparation process is simple and easy for large-scale production. Summary of the Invention
[0006] The purpose of this invention is to provide ceramics with large dielectric constant and low dielectric loss, and methods for preparing the same, in order to solve the problems mentioned in the background art.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] A ceramic material with a high dielectric constant and low dielectric loss, composed of CaCu3Ti4O 12 It is composed of Nb2O5, with the chemical formula CaCu3Ti 4-x Nb x O 12 Where 0≤x≤0.08, the pre-firing conditions are 950℃ for 15h, the glue removal conditions are 600℃ for 1h, and the sintering conditions are 1120℃ for 20h.
[0009] A method for preparing a ceramic with a large dielectric constant and low dielectric loss includes the following steps: Under an air atmosphere, using CaCO3, CuO, and TiO2 as raw materials and Nb2O5 as an additive, a solid-state reaction process is employed. This process involves mixing, pre-firing, molding, debinding, and sintering to obtain the ceramic material CaCu3Ti with a large dielectric constant and low dielectric loss. 4-x Nb x O 12 .
[0010] As a further technical solution of the present invention, the pre-firing conditions are to raise the temperature from room temperature to 950°C at a heating rate of 200°C / h and then keep it at that temperature for 15 hours.
[0011] As a further technical solution of the present invention, the glue removal condition is to keep the glue at 600°C for 1 hour.
[0012] As a further technical solution of the present invention, the sintering conditions are as follows: the temperature is increased from room temperature to 1000°C at a heating rate of 200°C / h, then increased to 1100-1120°C at a heating rate of 600°C / h, held at that temperature for 20 hours, and then cooled with the furnace.
[0013] As a further technical solution of the present invention, the specific steps are as follows: A component with a mass percentage content of CaCu3Ti is prepared by solid-state reaction at 1120℃ for 20 hours. 3.99 Nb 0.01 O 12 The ceramic material was prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder with a purity of 99.0% in a certain molar ratio, placing them in an agate ball mill jar for wet ball milling, using anhydrous ethanol as the milling medium, and milling at 360 r / min for 12 h using a planetary ball mill. The milled slurry was dried in an oven at 70℃, and then the dried powder was placed in a sintering furnace for pre-firing at 950℃. The pre-firing blocks were then ball-milled and dried again. Add an equal mass of PVA binder (2wt%), granulate and grind, and age the particles with a particle size between 60 mesh and 100 mesh for 24 hours. Use a powder press to dry press the aged particles into cylindrical green bodies with a diameter of about 12 mm and a thickness of about 2 mm under a pressure of about 10 MPa. Place the green bodies in a sintering furnace and perform a debinding treatment at 600°C. After the debinding treatment, place the green bodies back into the sintering furnace and sinter at 1120°C for 20 hours to obtain CCTO ceramic bodies.
[0014] As a further technical solution of the present invention, the mass ratio of raw materials: agate balls: anhydrous ethanol is 1:1 to 3:0.8 to 1.2.
[0015] Compared with the prior art, the beneficial effects of this invention are: This invention provides a method to reduce dielectric loss while maintaining the giant dielectric constant of CCTO ceramic materials. Specifically, by adding Nb2O5 to the formulation and through solid-state sintering, a ceramic material with a giant dielectric constant and low dielectric loss is obtained. At a test frequency of 16700Hz, its ε... r =15471, tanδ=0.08. Therefore, this invention prepares CCTO ceramic materials with a large dielectric constant and low dielectric loss, thus improving the dielectric properties of CCTO ceramic materials. This invention fully utilizes the solid-state method, which is simple, easy to operate, highly repeatable, and produces samples with high performance stability, making it easy to scale up production. Attached Figure Description
[0016] Figure 1 The figure shows the experimental results of Example 1.
[0017] Figure 2 The figure shows the experimental results of Example 2.
[0018] Figure 3 The figure shows the experimental results of Example 3.
[0019] Figure 4 The figure shows the experimental results of Example 4.
[0020] Figure 5 The figure shows the experimental results of Example 5.
[0021] Figure 6 The figure shows the experimental results of Example 6. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] Example 1:
[0024] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction method at 1100℃ for 20 h. 3.99 Nb 0.01 O 12Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1100℃ for 20 hours to obtain a CCTO ceramic body. The surface of the CCTO ceramic body was polished, gold electrodes were sputtered, and dielectric properties were tested. At room temperature, when the test frequency was 16732Hz, ε r =60288, tanδ=0.15. (See attached diagram) Figure 1 As shown by the curve.
[0025] Example 2:
[0026] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction at 1120℃ for 20 h. 3.99 Nb 0.01 O 12 Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1120℃ for 20 hours to obtain a CCTO ceramic body. The surface of the CCTO ceramic body was polished, gold electrodes were sputtered, and dielectric properties were tested. At room temperature, when the test frequency was 32796Hz, ε r =50160, tanδ=0.13. (See attached diagram) Figure 2As shown by the curve.
[0027] Example 3:
[0028] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction method at 1100℃ for 20 h. 3.96 Nb 0.04 O 12 Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1100℃ for 20 hours to obtain a CCTO ceramic body. The surface of the CCTO ceramic body was polished, gold electrodes were sputtered, and dielectric properties were tested. At room temperature, when the test frequency was 64280Hz, ε r =46902, tanδ=0.29. (See attached diagram) Figure 3 As shown by the curve.
[0029] Example 4:
[0030] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction at 1120℃ for 20 h. 3.96 Nb 0.04 O 12Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1120℃ for 20 hours to obtain a CCTO ceramic body. The surface of the CCTO ceramic body was polished, gold electrodes were sputtered, and dielectric properties were tested. At room temperature, when the test frequency was 16732Hz, ε r =22388, tanδ=0.087. (See attached diagram) Figure 4 As shown by the curve.
[0031] Example 5:
[0032] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction method at 1100℃ for 20 h. 3.92 Nb 0.08 O 12 Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1100℃ for 20 hours to obtain a CCTO ceramic body. The surface of the CCTO ceramic body was polished, gold electrodes were sputtered, and dielectric properties were tested. At room temperature, when the test frequency was 89992Hz, ε r =44135, tanδ=0.51. (See attached diagram) Figure 5 As shown by the curve.
[0033] Example 6:
[0034] The CaCu3Ti composition with a mass percentage content was prepared by solid-state reaction at 1120℃ for 20 h. 3.92 Nb 0.08 O 12 Ceramic materials were prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder (99.0% purity) in a specific molar ratio and wet-milling them in an agate ball mill jar using anhydrous ethanol as the milling medium at a mass ratio of raw material:agate balls:anhydrous ethanol = 1:1~3:0.8~1.2. The mixture was then milled for 12 hours at 360 r / min using a planetary ball mill. The milled slurry was dried at 70℃ in an oven, and then pre-fired at 950℃ in a sintering furnace. The pre-fired sintered blocks were ball-milled and dried again, and then granulated and ground with an equal mass of PVA binder (2wt%). Particles with a particle size between 60 and 100 mesh were aged for 24 hours. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of approximately 12 mm and a thickness of approximately 2 mm using a powder press at approximately 10 MPa. The green bodies were then placed in a sintering furnace at 600℃ for debinding. After debinding, the green body was placed in a sintering furnace and sintered at 1120℃ for 20 hours to obtain CCTO ceramic body. At room temperature, when the test frequency ranged from 1KHz to 90KHz, ε... r =16000~19000, tanδ≤0.1; and when the test frequency is 16732Hz, ε r =15471, tanδ=0.08. (See attached diagram) Figure 6 As shown by the curve.
[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A ceramic with a large dielectric constant and low dielectric loss, characterized in that, From CaCu3Ti4O 12 It is composed of Nb2O5, with the chemical formula CaCu3Ti 4-x Nb x O 12 Where 0.01≤x≤0.04, the pre-firing conditions are 950℃ for 15h, the glue removal conditions are 600℃ for 1h, and the sintering conditions are 1120℃ for 20h. The specific steps of the preparation method of the giant dielectric constant and low dielectric loss ceramic are as follows: under an air atmosphere, using CaCO₃... 3、 Using CuO and TiO2 as raw materials and Nb2O5 as an additive, a solid-state reaction process is employed. Through mixing, pre-firing, molding, debinding, and sintering, a ceramic material with a large dielectric constant and low dielectric loss, CaCu3Ti, can be obtained. 4-x Nb x O 12 The pre-firing conditions are: heating from room temperature to 950℃ at a heating rate of 200℃ / h and holding for 15h; the debinding conditions are: holding at 600℃ for 1h; the sintering conditions are: heating from room temperature to 1000℃ at a heating rate of 200℃ / h, heating to 1120℃ at a heating rate of 600℃ / h, holding for 20h, and then cooling with the furnace.
2. The high dielectric constant, low dielectric loss ceramic according to claim 1, characterized in that, The specific steps are as follows: Prepare components with a mass percentage content of CaCu3Ti by solid-state reaction method at 1120℃ for 20 hours. 3.99 Nb 0.01 O 12 The ceramic material was prepared by mixing CaCO3 powder, CuO powder, TiO2 powder, and Nb2O5 powder with a purity of 99.0% in a certain molar ratio, placing them in an agate ball mill jar for wet ball milling at 360 r / min for 12 h using anhydrous ethanol as the milling medium. The slurry was dried in an oven at 70 °C, and then the dried powder was placed in a sintering furnace for pre-firing at 950 °C. The pre-firing blocks were ball-milled and dried again, and an equal mass of PVA binder was added for granulation and grinding. The particles with a particle size between 60 mesh and 100 mesh were aged for 24 h. The aged particles were then dry-pressed into cylindrical green bodies with a diameter of 12 mm and a thickness of 2 mm using a powder press at a pressure of 10 MPa. The green bodies were placed in a sintering furnace for debinding at 600 °C, and then sintered in a sintering furnace at 1120 °C for 20 h to obtain CCTO ceramic bodies.
3. The high dielectric constant, low dielectric loss ceramic according to claim 2, characterized in that, The mass ratio of raw materials: agate balls: anhydrous ethanol is 1:1 to 3:0.8 to 1.2.