Composite ceramic dielectric material, method for preparing the same and use thereof

Abstract

The application provides a composite ceramic dielectric material, the composition of the composite ceramic dielectric material comprises ceramic material and glass ceramic material, the ceramic material comprises xBaTiO3-ySrTiO3, the glass ceramic material comprises aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, and the composition of the composite ceramic dielectric material does not comprise alkali metal elements. By introducing the glass ceramic with a specific composition into the ceramic material, the grain growth is inhibited, the prepared composite ceramic dielectric material has high dielectric constant and high breakdown field strength, based on the high performance of the material, the size of the capacitor can be significantly reduced under the premise of reaching the required technical index of the ceramic capacitor, and the composite ceramic dielectric material provided by the application does not contain lead and is more environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of ceramic capacitors, and relates to a composite ceramic dielectric material, its preparation method, and its application. Background Technology

[0002] As an indispensable basic component in electronic circuits, capacitors undertake key tasks such as energy storage, filtering, and coupling, and their performance directly affects the stability and efficiency of the entire circuit system. There are many types of capacitors on the market. Electrolytic capacitors, with their large capacitance, hold a place in the power supply filtering field, while film capacitors excel in audio circuits due to their excellent insulation properties and low loss. In specific scenarios such as high-frequency circuits and miniaturized devices, ceramic capacitors, with their unique material properties and structural design, exhibit unparalleled advantages and are gradually becoming one of the core components of modern electronics.

[0003] Under the benchmark requirement of low loss, high dielectric constant, high breakdown field strength, and environmentally friendly material properties are the core elements for improving the performance of ceramic capacitors and successfully achieving market promotion. However, most current ceramic capacitors cannot meet all the requirements and have shortcomings.

[0004] For example, CN1212443A provides a high dielectric and high performance medium-temperature sintered multilayer ceramic capacitor material. Although the material has a high dielectric constant, it does not perform well in terms of voltage withstand performance. Furthermore, the ceramic material contains a certain amount of lead, which greatly limits its application.

[0005] CN1306288A discloses a high-voltage ceramic capacitor dielectric. Although the ceramic dielectric of this capacitor is a lead-free dielectric material and its DC withstand voltage can reach more than 10kV / mm, its dielectric constant is relatively small. The low dielectric constant makes it difficult for the capacitor to store enough charge in a limited space during the miniaturization process, which cannot meet the requirements of modern electronic devices for high performance and miniaturization. In addition, the sintering temperature of this dielectric is relatively high, which increases the energy consumption and cost in the production process, which is not conducive to the large-scale production and market promotion of the product.

[0006] Therefore, how to prepare a ceramic capacitor that combines low loss, high dielectric constant, high breakdown field strength, and environmentally friendly materials is an urgent technical problem to be solved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a composite ceramic dielectric material, its preparation method, and its applications. This invention introduces a microcrystalline glass of a specific composition into a ceramic material, suppressing grain growth. The resulting composite ceramic dielectric material possesses high dielectric constant and high breakdown field strength. Based on the material's high performance, the size of the capacitor can be significantly reduced while meeting the required technical specifications of ceramic capacitors. Furthermore, the composite ceramic dielectric material provided by this invention is lead-free, making it more environmentally friendly.

[0008] To achieve this objective, the present invention employs the following technical solution:

[0009] In a first aspect, the present invention provides a composite ceramic dielectric material, the composite ceramic dielectric material comprising ceramic material and microcrystalline glass material, the ceramic material comprising xBaTiO3-ySrTiO3, the microcrystalline glass material comprising aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, and the composite ceramic dielectric material excluding alkali metal elements.

[0010] In this invention, BaO and SrO can form a solid solution with ceramic materials, making the crystal structure more complete and dense, thereby hindering electron migration and increasing the breakdown field strength; Bi2O3 can form a thin glassy phase on the surface of ceramic particles, improving the interfacial bonding between ceramic particles. This glassy phase can uniformly disperse the electric field, avoiding electric field concentration at the particle interface and increasing the breakdown field strength; furthermore, Bi in Bi2O3... 3+ With its unique electron cloud structure, Bi₂O₃'s electron cloud distribution is easily distorted under an electric field, producing a certain polarization effect. Simultaneously, the interaction between Bi₂O₃ and other components also affects the internal electron cloud distribution, further promoting the polarization process and increasing the material's dielectric constant. The synergistic effect of these various substances ultimately results in a composite ceramic dielectric material exhibiting high dielectric constant and breakdown field strength.

[0011] Furthermore, the composite ceramic dielectric material provided by this invention does not contain alkali metal elements. This is because alkali metal elements generally have large ionic radii, and their addition to the composite ceramic dielectric material would introduce significant stress into the crystal lattice, leading to lattice distortion. This would cause defects and weak regions to form within the material. Under the influence of an electric field, these areas are prone to becoming initiation points for electron avalanches, reducing the material's breakdown field strength and making it susceptible to breakdown failure even at relatively low voltages.

[0012] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0013] Preferably, the mass ratio of the ceramic material to the microcrystalline glass material is 100:(1~9), more preferably 100:(5~8), for example 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8 or 100:9, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0014] In this invention, the mass ratio of ceramic material to glass-ceramic material affects the performance of the composite ceramic dielectric material. By controlling it within the above-mentioned preferred range, the glass-ceramic material can fully fill the defects in the ceramic without forming a continuous network structure. Therefore, it can effectively improve the interfacial bonding, suppress defect propagation, homogenize the electric field distribution, and effectively increase the overall polarization of the material while maintaining the strength and toughness of the ceramic material, thus significantly improving the dielectric constant and breakdown field strength of the material.

[0015] Preferably, in the xBaTiO3-ySrTiO3, x:y = (68~78):(22~32), where x:y is a molar ratio, such as 68:32, 69:31, 70:30, 71:29, 72:28, 73:27, 74:26, 75:25, 76:24, 77:23, or 78:22, etc., but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0016] Preferably, in the aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, a:b:c:d:e:f=(0.2~0.3):(0.05~0.15):(0.2~0.4):(0.5~1):(5~7):(1~3), where a:b:c:d:e:f is a molar ratio, for example 0.2:0.05:0.2:0.5:5:1, 0 The values ​​are 0.22:0.07:0.25:0.6:5.5:1.5, 0.25:0.08:0.3:0.7:6:2, 0.28:0.1:0.3:0.0.8:6:2, 0.28:0.1:0.35:0.8:6.5:2.5, or 0.3:0.15:0.4:1:7:3, etc., but are not limited to the listed values; other unlisted values ​​within this range also apply.

[0017] In this invention, by controlling the composition of the ceramic material and the microcrystalline glass within the aforementioned preferred ranges, the materials can exhibit better performance. For example, insufficient BaTiO3 content in the ceramic material will adversely affect the improvement of the material's dielectric constant; insufficient SrO or Bi2O3 content in the microcrystalline glass will adversely affect the improvement of the material's dielectric constant and breakdown field strength.

[0018] Preferably, the D50 of the microcrystalline glass is 0.1μm to 1μm, such as 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm or 1μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] In this invention, the microcrystalline glass has a smaller particle size, which gives it a larger specific surface area and a greater number of surface atoms. Under the influence of an electric field, these surface atoms are more likely to polarize, thereby increasing the polarization intensity of the material and improving the dielectric constant. In addition, the smaller microcrystalline glass has a larger contact area with the ceramic particles, which is conducive to forming a tighter and more uniform bond at the interface. This good interfacial bond can effectively transfer stress, improve the mechanical properties of the material, and also help stabilize the microstructure of the material, reduce the electric field concentration phenomenon caused by interface defects, and improve the breakdown field strength and dielectric stability of the material.

[0020] In a second aspect, the present invention provides a method for preparing a composite ceramic dielectric material as described in the first aspect, the method comprising:

[0021] (1) Mix Ba source, Sr source, Bi source, Ti source, Si source and Al source to obtain a glass-ceramic precursor. Melt the glass-ceramic precursor and quench it. Then ball mill, dry and sieve to obtain aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3.

[0022] (2) Mix BaTiO3 and SrTiO3 to obtain xBaTiO3-ySrTiO3;

[0023] (3) The microcrystalline glass material described in step (1), the ceramic material described in step (2), and the solvent are mixed, dried, pressed and sintered to obtain the composite ceramic medium material.

[0024] The preparation method provided by the present invention is simple. It only requires preparing microcrystalline glass first, and then mixing and sintering it with ceramic materials to obtain a composite ceramic dielectric material with high dielectric constant and high breakdown field strength. In addition, adding Bi source in step (1) is also beneficial to reduce the melting temperature of microcrystalline glass and save energy consumption.

[0025] Preferably, in step (1), the Ba source includes BaCO3, the Sr source includes SrCO3, the Bi source includes Bi2O3, the Ti source includes TiO2, the Si source includes SiO2, and the Al source includes Al2O3.

[0026] Preferably, the Ba source, Sr source, Bi source, Ti source, Si source and Al source are weighed according to the values ​​of a, b, c, d, e and f in the aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3.

[0027] Preferably, the melting temperature in step (1) is 1500℃~1600℃, such as 1500℃, 1510℃, 1520℃, 1530℃, 1540℃, 1550℃, 1560℃, 1570℃, 1580℃, 1590℃ or 1600℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the melting time in step (1) is 1h to 3h, such as 1h, 1.5h, 2h, 2.5h or 3h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the quenching device in step (1) includes a roller mill with a gap of 0.5mm to 1mm, such as 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the ball-to-material ratio in step (1) is (3~5):1, such as 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] In this invention, by using a roller mill for quenching and controlling the ball-to-material ratio of the ball mill at (3~5):1, the prepared microcrystalline glass can have a smaller particle size.

[0032] Preferably, the ball milling time in step (1) is 3h to 5h, such as 3h, 3.5h, 4h, 4.5h or 5h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the xBaTiO3-ySrTiO3 described in step (2) is pre-calcined.

[0034] Preferably, the preheating temperature is 1000℃~1100℃, such as 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃ or 1100℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] In this invention, pre-firing xBaTiO3-ySrTiO3 is more conducive to forming an integral core structure and improving dielectric properties.

[0036] Preferably, in step (2), the mixed BaTiO3 and SrTiO3 are weighed according to the values ​​of x and y in xBaTiO3-ySrTiO3.

[0037] Preferably, the mixing method in step (3) includes ball milling.

[0038] Preferably, the ball milling time is 5h to 7h, such as 5h, 5.5h, 6h, 6.5h or 7h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, granulation is performed before pressing and molding in step (3).

[0040] Preferably, the pressing pressure in step (3) is 280MPa~320MPa, such as 280MPa, 290MPa, 300MPa, 310MPa or 320MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the temperature for discharging adhesive in step (3) is 500℃~700℃, such as 500℃, 550℃, 600℃, 650℃ or 700℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the time for degumming in step (3) is 2h to 4h, such as 2h, 2.5h, 3h, 3.5h or 4h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the sintering temperature in step (3) is 1190℃~1230℃, such as 1190℃, 1200℃, 1210℃, 1220℃ or 1230℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] In this invention, by introducing microcrystalline glass into ceramic materials, the sintering temperature of the materials can be reduced.

[0045] Preferably, the holding time for sintering in step (3) is 1h to 3h, such as 1h, 1.5h, 2h, 2.5h or 3h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Thirdly, the present invention also provides the application of the composite ceramic dielectric material as described in the first aspect or the composite ceramic dielectric material prepared by the preparation method described in the second aspect in ceramic capacitors.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] This invention introduces microcrystalline glass with a specific composition into ceramic materials to suppress grain growth, resulting in a composite ceramic dielectric material with high dielectric constant and high breakdown field strength. The dielectric constant can reach up to 3000, and the breakdown field strength is >15kV / mm. Based on the high performance of the material, the size of the capacitor can be significantly reduced while meeting the technical specifications required for ceramic capacitors. Furthermore, the composite ceramic dielectric material provided by this invention does not contain lead, making it more environmentally friendly. Detailed Implementation

[0049] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0050] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion.

[0051] Example 1

[0052] This embodiment provides a composite ceramic dielectric material, comprising a ceramic material and a microcrystalline glass material. The ceramic material is xBaTiO3-ySrTiO3, where x:y = 72:28, and the microcrystalline glass material is aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, where a:b:c:d:e:f = 0.28:0.1:0.3:0.8:6:2, and the mass ratio of the ceramic material to the microcrystalline glass material is 100:7. The preparation method is as follows:

[0053] (1) Weigh BaCO3, SrCO3, Bi2O3, TiO2, SiO2 and Al2O3 in molar ratios a=0.28, b=0.1, c=0.3, d=0.0.8, e=6 and f=2 and mix them to obtain a glass precursor. Melt the glass precursor at 1550℃ for 2h, quench it in a roller mill with a gap of 0.8mm to form glass sheets, then ball mill in a ball mill jar with a ball-to-material ratio of 4:1 for 4h, and then dry and sieve to obtain microcrystalline glass material;

[0054] (2) BaTiO3 and SrTiO3 are mixed in a molar ratio of x=72 and y=28 to obtain a ceramic material;

[0055] (3) Weigh the ceramic material and microcrystalline glass according to a mass ratio of 100:7, and place them and deionized water in a ball mill jar for 6 hours. After drying, press them under 300MPa to form small round pieces with a diameter of 10mm and a thickness of 1mm. Remove the glue at 600℃ for 3 hours, and then keep them at 1200℃ for 2 hours to obtain composite ceramic media material.

[0056] Example 2

[0057] This embodiment provides a composite ceramic dielectric material, comprising a ceramic material and a microcrystalline glass material. The ceramic material is xBaTiO3-ySrTiO3, where x:y = 68:32, and the microcrystalline glass material is aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, where a:b:c:d:e:f = 0.2:0.05:0.2:0.5:5:1, and the mass ratio of the ceramic material to the microcrystalline glass material is 100:5. The preparation method is as follows:

[0058] (1) Weigh BaCO3, SrCO3, Bi2O3, TiO2, SiO2 and Al2O3 in molar ratios a=0.2, b=0.05, c=0.2, d=0.5, e=5 and f=1 and mix them to obtain a glass precursor. Melt the glass precursor at 1500℃ for 3h, quench it in a roller mill with a gap of 0.5mm to form glass sheets, then ball mill in a ball mill jar with a ball-to-material ratio of 3:1 for 5h, and then dry and sieve to obtain microcrystalline glass material;

[0059] (2) BaTiO3 and SrTiO3 are mixed in a molar ratio of x=68 and y=32 to obtain a ceramic material;

[0060] (3) Weigh the ceramic material and microcrystalline glass according to a mass ratio of 100:5, and place them and deionized water in a ball mill jar for 5 hours. After drying, press them at 280MPa to form small round discs with a diameter of 10mm and a thickness of 1mm. Remove the glue at 500℃ for 4 hours and keep them at 1190℃ for 3 hours to obtain composite ceramic media material.

[0061] Example 3

[0062] This embodiment provides a composite ceramic dielectric material, comprising a ceramic material and a microcrystalline glass material. The ceramic material is xBaTiO3-ySrTiO3, where x:y = 78:22, and the microcrystalline glass material is aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, where a:b:c:d:e:f = 0.3:0.15:0.4:1:7:3, and the mass ratio of the ceramic material to the microcrystalline glass material is 100:8. The preparation method is as follows:

[0063] (1) Weigh BaCO3, SrCO3, Bi2O3, TiO2, SiO2 and Al2O3 in molar ratios a=0.3, b=0.15, c=0.4, d=1, e=7 and f=3 and mix them to obtain a glass precursor. Melt the glass precursor at 1600℃ for 1h, quench it in a roller mill with a gap of 1mm to form a glass sheet, then ball mill it in a ball mill jar with a ball-to-material ratio of 5:1 for 3h, and then dry and sieve it to obtain a microcrystalline glass material.

[0064] (2) BaTiO3 and SrTiO3 are mixed in a molar ratio of x=78 and y=22 to obtain a ceramic material;

[0065] (3) Weigh the ceramic material and microcrystalline glass according to a mass ratio of 100:8, and place them and deionized water in a ball mill jar for 7 hours. After drying, press them at 320MPa to form small round pieces with a diameter of 10mm and a thickness of 1mm. Remove the glue at 700℃ for 2 hours and keep them at 1230℃ for 1 hour to obtain composite ceramic media material.

[0066] Example 4

[0067] The difference between this embodiment and embodiment 1 is that in this embodiment, after mixing BaTiO3 and SrTiO3, step (2) is pre-fired at 1050°C for 1 hour to obtain ceramic material;

[0068] The remaining preparation methods and parameters are consistent with those in Example 1.

[0069] Example 5

[0070] The difference between this embodiment and embodiment 1 is that in this embodiment, step (3) involves weighing the ceramic material and the microcrystalline glass at a mass ratio of 100:10.

[0071] The remaining preparation methods and parameters are consistent with those in Example 1.

[0072] Example 6

[0073] The difference between this embodiment and embodiment 1 is that in this embodiment, step (3) involves weighing the ceramic material and the microcrystalline glass at a mass ratio of 100:1.

[0074] The remaining preparation methods and parameters are consistent with those in Example 1.

[0075] Example 7

[0076] The difference between this embodiment and embodiment 1 is that in this embodiment, the ceramic material is xBaTiO3-ySrTiO3, where x:y=28:72. In step (2) of the preparation method, BaTiO3 and SrTiO3 are mixed in a molar ratio of x=28 and y=72 to obtain the ceramic material.

[0077] The remaining preparation methods and parameters are consistent with those in Example 1.

[0078] Example 8

[0079] The difference between this embodiment and Embodiment 1 is that, in this embodiment, the microcrystalline glass material is aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, where a:b:c:d:e:f=0.28:0.1:0.5:0.8:6:2. In step (1) of the preparation method, BaCO3, SrCO3, Bi2O3, TiO2, SiO2 and Al2O3 are weighed and mixed in a molar ratio of a=0.28, b=0.1, c=0.5, d=0.0.8, e=6 and f=2 to obtain the glass precursor;

[0080] The remaining preparation methods and parameters are consistent with those in Example 1.

[0081] Example 9

[0082] The difference between this embodiment and embodiment 1 is that step (1) will use a double-roll mill for quenching instead of water quenching;

[0083] The remaining preparation methods and parameters are consistent with those in Example 1.

[0084] Comparative Example 1

[0085] The difference between this comparative example and Example 1 is that no microcrystalline glass material is added in this comparative example, and step (1) is not performed in the preparation method.

[0086] The remaining preparation methods and parameters are consistent with those in Example 1.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that in this comparative example, the ceramic material is xBaTiO3-ySrTiO3-zNa2CO3, where x:y:z=59:23:18. In step (2) of the preparation method, BaTiO3, SrTiO3 and Na2CO3 are mixed in a molar ratio of x=59, y=23 and z=18 to obtain the ceramic material.

[0089] The remaining preparation methods and parameters are consistent with those in Example 1.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 1 is that in this comparative example, the microcrystalline glass material is aBaO-bSrO-dTiO2-eSiO2-fAl2O3, where a:b:d:e:f=0.28:0.1:0.3:0.8:6:2. In step (1) of the preparation method, BaCO3, SrCO3, TiO2, SiO2 and Al2O3 are weighed and mixed in a molar ratio of a=0.28, b=0.1, d=0.0.8, e=6 and f=2 to obtain the glass precursor.

[0092] The remaining preparation methods and parameters are consistent with those in Example 1.

[0093] Comparative Example 4

[0094] The difference between this comparative example and Example 1 is that in this comparative example, the microcrystalline glass material is aBaO-cBi2O3-dTiO2-eSiO2-fAl2O3, where a:c:d:e:f=0.28:0.3:0.8:6:2. BaCO3, Bi2O3, TiO2, SiO2 and Al2O3 are weighed and mixed in the molar ratio of a=0.28, c=0.3, d=0.0.8, e=6 and f=2 to obtain the glass precursor.

[0095] The remaining preparation methods and parameters are consistent with those in Example 1.

[0096] Performance testing

[0097] The particle size of the microcrystalline glass prepared in Examples 1-9 and Comparative Examples 2-4 was tested, and silver electrodes were printed on the end face of the composite ceramic dielectric material prepared in Examples 1-9 and Comparative Examples 1-4. The ceramic capacitor was prepared by holding it at 800℃ for 15 min. The dielectric properties were tested using a Tonghui TH2838A LCR meter, and the withstand voltage was tested using an LK2674A. The test results are shown in Table 1.

[0098] Table 1

[0099]

[0100] As can be seen from the comparison of the data of Examples 1-3 and Comparative Examples 1-4 in Table 1, in this invention, the microcrystalline glass and ceramic materials with specific compositions work synergistically to improve the dielectric constant and breakdown field strength of the composite ceramic dielectric material. In particular, Bi2O3 and SrO in the microcrystalline glass play an important role in improving the performance of the composite material and are indispensable components. Furthermore, if the composite ceramic dielectric material contains alkali metal elements, it will lead to a decrease in material performance.

[0101] A comparison of the data from Examples 1 and 4 in Table 1 shows that pre-firing xBaTiO3-ySrTiO3 is more beneficial to improving material performance. A comparison of the data from Examples 1 and 5-8 in Table 1 shows that the mass ratio of ceramic material to glass-ceramic, the molar ratio of BaTiO3 to SrTiO3, and the molar percentage of Bi2O3 in glass-ceramic all affect the performance of the composite ceramic material. Controlling these within the preferred range of this invention is more beneficial to improving material performance. Furthermore, a comparison of the data from Examples 1 and 9 in Table 1 shows that the quenching method also affects material performance. By adopting the preferred quenching method of this invention, better results can be achieved.

[0102] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A composite ceramic dielectric material, characterized in that, The composite ceramic medium material comprises ceramic materials and microcrystalline glass materials. The ceramic materials include xBaTiO3-ySrTiO3, and the microcrystalline glass materials include aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3. The composite ceramic medium material does not contain alkali metal elements.

2. The composite ceramic dielectric material according to claim 1, characterized in that, The mass ratio of the ceramic material to the microcrystalline glass material is 100:(1~9), preferably 100:(5~8).

3. The composite ceramic dielectric material according to claim 1 or 2, characterized in that, In the xBaTiO3-ySrTiO3, x:y = (68~78):(22~32), where x:y is the molar ratio; Preferably, in the aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3, a:b:c:d:e:f=(0.2~0.3):(0.05~0.15):(0.2~0.4):(0.5~1.0):(5~7):(1~3), where a:b:c:d:e:f is the molar ratio.

4. The composite ceramic dielectric material according to any one of claims 1-3, characterized in that, The D50 of the microcrystalline glass is 0.1μm~1μm.

5. A method for preparing a composite ceramic dielectric material as described in any one of claims 1-4, characterized in that, The preparation method includes: (1) Mix Ba source, Sr source, Bi source, Ti source, Si source and Al source to obtain a glass-ceramic precursor. Melt the glass-ceramic precursor and quench it. Then ball mill, dry and sieve to obtain aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3. (2) Mix BaTiO3 and SrTiO3 to obtain xBaTiO3-ySrTiO3; (3) The microcrystalline glass material described in step (1), the ceramic material described in step (2), and the solvent are mixed, dried, pressed and molded, and then sintered to obtain the composite ceramic medium material.

6. The method for preparing the composite ceramic dielectric material according to claim 5, characterized in that, In step (1), the Ba source includes BaCO3, the Sr source includes SrCO3, the Bi source includes Bi2O3, the Ti source includes TiO2, the Si source includes SiO2, and the Al source includes Al2O3. Preferably, the Ba source, Sr source, Bi source, Ti source, Si source and Al source are weighed according to the values ​​of a, b, c, d, e and f in the aBaO-bSrO-cBi2O3-dTiO2-eSiO2-fAl2O3.

7. The method for preparing the composite ceramic dielectric material according to claim 5 or 6, characterized in that, The melting temperature in step (1) is 1500℃~1600℃; Preferably, the melting time in step (1) is 1h to 3h; Preferably, the quenching apparatus in step (1) includes a roller mill with a gap of 0.5 mm to 1 mm. Preferably, the ball-to-material ratio in step (1) is (3~5):1; Preferably, the ball milling time in step (1) is 3h to 5h.

8. The method for preparing the composite ceramic dielectric material according to any one of claims 5-7, characterized in that, The xBaTiO3-ySrTiO3 described in step (2) is pre-calcined; Preferably, the pre-firing temperature is 1000℃~1100℃; Preferably, in step (2), the mixed BaTiO3 and SrTiO3 are weighed according to the values ​​of x and y in xBaTiO3-ySrTiO3.

9. The method for preparing the composite ceramic dielectric material according to any one of claims 5-8, characterized in that, The mixing method described in step (3) includes ball milling; Preferably, the ball milling time is 5h~7h; Preferably, the pressing pressure in step (3) is 280MPa~320MPa; Preferably, the temperature for degreasing in step (3) is 500℃~700℃; Preferably, the glue removal time in step (3) is 2h~4h; Preferably, the sintering temperature in step (3) is 1190℃~1230℃; Preferably, the holding time for sintering in step (3) is 1h to 3h.

10. The application of a composite ceramic dielectric material as described in any one of claims 1-4 or a composite ceramic dielectric material prepared by the preparation method described in any one of claims 5-9 in a ceramic capacitor.

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