Barium titanate-based ceramic material, method for the production thereof and use thereof

Abstract

The application provides a barium titanate-based ceramic material and a preparation method and application thereof. The barium titanate-based ceramic material comprises a ceramic main material and a glass auxiliary material. The ceramic main material comprises BaTiO3, and the glass auxiliary material comprises BaO, B2O3, SiO2, Nb2O5, MnO and La2O3. The sintering temperature of the barium titanate-based ceramic material is 850-1000 DEG C, the barium titanate-based ceramic material can be co-sintered with an internal electrode in a multilayer ceramic capacitor preparation process, the dielectric constant of the prepared ceramic capacitor is high (2500-3000), the loss is low (<0.3%), and the temperature coefficient meets X7P. In addition, the preparation method is simple and suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, and relates to a barium titanate-based ceramic material, its preparation method, and its application. Background Technology

[0002] With the rapid development of consumer electronics, communication equipment, and automotive electronics towards thinner, smaller, and higher performance, the demand for miniaturization of electronic components is becoming increasingly urgent. Multilayer ceramic capacitors (MLCCs), as an indispensable basic component in electronic circuits, are seeing miniaturization and higher capacitance become the mainstream trends in technological development.

[0003] The core dielectric material of MLCCs is barium titanate (BaTiO3)-based ceramic, which is widely used due to its high dielectric constant and good insulation properties. However, the sintering temperature of traditional barium titanate ceramics is relatively high (usually above 1300°C), requiring co-firing with the internal electrode in the actual MLCC manufacturing process. Early MLCCs often used precious metals such as silver-palladium (Ag-Pd) as internal electrode materials, but the high price and scarcity of precious metals have limited their widespread application in large-scale consumer electronics.

[0004] To reduce production costs, the internal electrode materials for MLCCs are increasingly shifting towards base metals such as nickel (Ni) and copper (Cu). However, base metals are highly susceptible to oxidation under high-temperature sintering conditions, necessitating co-firing in a reducing atmosphere or under low oxygen partial pressure. This also places stricter requirements on the sintering temperature—typically requiring temperatures below 1100°C, or even lower, to prevent oxidation failure of the base metal electrodes. This need has driven in-depth research into low-temperature co-fired ceramic technology.

[0005] The key challenge in low-temperature co-fired barium titanate ceramic materials lies in maintaining excellent dielectric properties (such as high dielectric constant and low dielectric loss) and good temperature stability (such as meeting EIA standards like X7P and X7R) while lowering the sintering temperature. Current technologies primarily involve adding low-melting-point substances (such as oxides, borates, or silicate systems) as sintering aids. However, traditional methods of introducing sintering aids often suffer from the following problems: Firstly, the reaction between the sintering aid and the ceramic matrix is ​​difficult to control precisely; excessive reaction can easily generate non-target impurity phases, leading to deterioration of dielectric properties. Secondly, the distribution uniformity of the sintering aid in the ceramic matrix is ​​insufficient; local enrichment or depletion can cause inconsistent sintering densification behavior, thus affecting the microstructure uniformity of the ceramic material and the reliability of MLCC products.

[0006] Therefore, developing a barium titanate-based ceramic material that can be sintered at low temperatures (≤1100°C) while maintaining excellent dielectric properties and temperature stability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a barium titanate-based ceramic material, its preparation method, and its applications. The barium titanate-based ceramic material provided by this invention has a sintering temperature of 850℃~1000℃, allowing for co-firing with the internal electrode during actual MLCC fabrication. Furthermore, the prepared ceramic capacitor exhibits a high dielectric constant (2500~3000), low loss (<0.3%), and a temperature coefficient satisfying X7P. Moreover, the preparation method provided by this invention is simple and suitable for widespread application.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a barium titanate-based ceramic material, the barium titanate-based ceramic material comprising a ceramic main material and a glass auxiliary material, the ceramic main material comprising BaTiO3, and the glass auxiliary material comprising BaO, B2O3, SiO2, Nb2O5, MnO and La2O3.

[0009] In this invention, barium titanate-based ceramic materials significantly improve dielectric properties while lowering the co-firing temperature of MLCCs through the synergistic effect of the main ceramic material BaTiO3 and multi-element glass additives. Specifically, B2O3 and SiO2 in the glass additives can form a liquid phase at low temperatures, promoting densification of the main ceramic material and lowering the sintering temperature, thus enabling co-firing with copper or silver internal electrodes. BaO compensates for the volatilization loss of Ba at the A-sites of the main ceramic material, while Nb2O5 and La2O3 doping into the BaTiO3 lattice jointly regulate the temperature coefficient to meet the X7P characteristic. MnO doping enriches at grain boundaries, inhibiting BaTiO3 reduction and significantly reducing dielectric loss. Simultaneously, the glass additives inhibit abnormal grain growth, maintain a fine-grained structure, and ensure a high dielectric constant. The synergistic effect of these multiple elements through liquid-phase sintering, lattice doping, and grain boundary regulation comprehensively optimizes the material properties.

[0010] 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.

[0011] Preferably, the ceramic main material further includes Ce, and Ce is doped in the BaTiO3.

[0012] Preferably, the amount of Ce doped in the BaTiO3 is 0.1 mol% to 0.5 mol%, for example, 0.1 mol%, 0.2 mol%, 0.3 mol%, 0.4 mol%, or 0.5 mol%.

[0013] In this invention, compared to only occupying position A (such as La) 3+ ) or B position (such as Y)3+ rare earth elements, Ce 3+ Ba can be replenished by evaporation at site A, and Ce can be added. 4+ It can be used to control the lattice at the B site, and by combining it with a doping amount of 0.1% to 0.5%, it can better balance grain refinement, temperature stability and low loss.

[0014] Preferably, the molar ratio of BaO, B2O3, SiO2, Nb2O5, MnO and La2O3 is (0.25~0.35):(0.8~1.2):1:(0.25~0.35):(0.1~0.2):(0.01~0.02), for example 0.25:0.8:1:0.25:0.1:0.01, 0.27:0.9:1:0.28:0.12:0.012, 0.3:1:1:0.3:0.15:0.015, 0.32:1.1:1:0.32:0.18:0.018 or 0.35:1.2:1:0.35:0.2:0.02, etc.

[0015] In this invention, by controlling the above-mentioned components within a preferred range, it is also possible to better balance grain refinement, temperature stability, and low loss.

[0016] Preferably, the mass ratio of the ceramic main material to the glass auxiliary material is 98:(1~3), such as 98:1, 98:1.5, 98:2, 98:2.5 or 98:3, etc.

[0017] In this invention, by controlling the mass ratio of ceramic main material to glass auxiliary material at 98:(1~3), low-temperature co-firing can be achieved while avoiding the adverse effects of excessive glass auxiliary material. For example, excessive glass auxiliary material will dilute the high dielectric ceramic main material, causing a significant decrease in dielectric constant, hindering polarization, increasing losses, and reducing reliability.

[0018] Preferably, the barium titanate-based ceramic material has a particle size ≤300nm, such as 50nm, 100nm, 150nm, 200nm, 250nm or 300nm.

[0019] In a second aspect, the present invention provides a method for preparing a barium titanate-based ceramic material as described in the first aspect, the method comprising: S1. Mix the first Ba source, Ti source and the first solvent and perform a first ball milling, and obtain the ceramic main material after a first sintering; S2. The second Ba source, B source, Si source, Nb source, Mn source, La source and the second solvent are mixed and stirred until they reach a sol state. After aging and sintering, glass additives are obtained. S3. Mix the ceramic main material and the glass auxiliary material and perform a second ball milling to obtain the barium titanate-based ceramic material.

[0020] This invention first prepares the ceramic main material and glass auxiliary material separately, and then mixes and ball-mills them. Compared with directly mixing all raw materials, ball-milling and sintering, it can avoid the solid-phase pre-reaction between the components in the glass auxiliary material and BaTiO3 before sintering, ensuring the integrity of the main crystal phase structure and maintaining a high dielectric constant.

[0021] Preferably, in step S1, the first Ba source includes BaCO3.

[0022] Preferably, the Ti source in step S1 includes TiO2.

[0023] Preferably, in step S1, the molar ratio of the first Ba source to the Ti source is 1:(0.8~1.2), such as 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2, etc.

[0024] Preferably, in step S1, the first solvent includes water.

[0025] Preferably, Ce salt is added during the first ball milling process in step S1.

[0026] Preferably, the Ce salt comprises cerium nitrate.

[0027] Preferably, in step S1, the first ball milling produces product particles with a particle size ≤ 0.3 μm, such as 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, or 0.3 μm.

[0028] Preferably, before the first sintering in step S1, the product from the first ball milling is spray-dried.

[0029] Preferably, the temperature of the first sintering in step S1 is 1350℃~1450℃, such as 1350℃, 1380℃, 1400℃, 1420℃ or 1450℃, and the time is 4h~6h, such as 4h, 4.5h, 5h, 5.5h or 6h.

[0030] Preferably, the mixing step S2 is as follows: first, the B source and the Si source are dissolved in the second solvent, and then the Ba source, Mn source and La source are added sequentially under the second stirring condition, and then the Nb source is added after dissolution.

[0031] Preferably, the second Ba source in step S2 includes a Ba salt, and more preferably barium nitrate.

[0032] Preferably, the Mn source in step S2 includes Mn salt, and more preferably manganese nitrate.

[0033] Preferably, the La source in step S2 includes a La salt, and more preferably lanthanum nitrate.

[0034] Preferably, the source B in step S2 includes a borate ester.

[0035] Preferably, the Si source in step S2 includes a silicate ester.

[0036] Preferably, the mass ratio of the B source to the Si source in step S2 is (1.8~2.2):1, such as 1.8:1, 1.9:1, 2:1, 2.1:1 or 2.2:1, etc.

[0037] Preferably, the Nb source in step S2 includes an aqueous solution of (NH4)3[NbO(C2O4)].

[0038] Preferably, the mass concentration of the (NH4)3[NbO(C2O4)] aqueous solution is 4wt.%~6wt.%, for example, 4wt.%, 4.5wt.%, 5wt.%, 5.5wt.% or 6wt.%.

[0039] Preferably, in step S2, the second solvent comprises ethanol and water.

[0040] Preferably, the volume percentage of ethanol in the second solvent is 60% to 80%, such as 60%, 65%, 70%, 75%, or 80%.

[0041] Preferably, the stirring time in step S2 is 7h to 9h, for example, 7h, 7.5h, 8h, 8.5h or 9h.

[0042] Preferably, the aging temperature in step S2 is 50℃~70℃, such as 50℃, 55℃, 60℃, 65℃ or 70℃, and the time is 15h~18h, such as 15h, 16h, 17h or 18h.

[0043] Preferably, before the second sintering in step S2, the aged product is sequentially dried, ball-milled, and sieved.

[0044] Preferably, the drying temperature is 230℃~270℃, such as 230℃, 240℃, 250℃, 260℃ or 270℃.

[0045] Preferably, the temperature of the second sintering in step S2 is 500℃~700℃, for example 500℃, 550℃, 600℃, 650℃ or 700℃, and the time is 4h~6h, for example 4h, 4.5h, 5h, 5.5h or 6h.

[0046] Preferably, anhydrous ethanol is added during the second ball milling process in step S3.

[0047] Preferably, in step S3, the second ball milling is performed until the particle size of the product is ≤300nm, for example, 50nm, 100nm, 150nm, 200nm, 250nm or 300nm.

[0048] Preferably, after the second ball milling in step S3, the ball milling product is dried and sieved sequentially to obtain the barium titanate-based ceramic material.

[0049] Thirdly, the present invention provides an application of barium titanate-based ceramic materials as described in the first aspect in ceramic capacitors.

[0050] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0051] Compared with the prior art, the present invention has the following beneficial effects: The barium titanate-based ceramic material provided by this invention has a sintering temperature of 850℃~1000℃, allowing it to be co-fired with the internal electrode during actual MLCC fabrication. The resulting ceramic capacitor exhibits a high dielectric constant (2500~3000), low loss (<0.3%), and a temperature coefficient that meets the X7P standard. Furthermore, the fabrication method provided by this invention is simple and suitable for widespread application. Detailed Implementation

[0052] 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.

[0053] "The scope of this invention can be defined by a lower limit and an upper limit. The selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower limit and upper limit values ​​can be arbitrarily combined to form a new range. That is, any lower limit value can be combined with any upper limit value to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then 1~3, 1~4, and 2~3, 1~4, 2~5 ... All ranges from 1 to 5, 2 to 3, 2 to 4, and 2 to 5 fall within the scope of this invention. In this invention, the numerical range "a to b" represents a shortened representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0 to 5" indicates that all real numbers between 0 and 5 have been fully listed in this document; "0 to 5" is merely a shortened representation of this numerical combination. When a parameter is expressed as an integer ≥ 2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, and 10. When a parameter is expressed as an integer selected from "2 to 10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0054] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0055] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0056] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0057] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0058] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0059] Example 1 This embodiment provides a barium titanate-based ceramic material, comprising a Ce-doped BaTiO3 ceramic substrate (molar doping amount of 0.3%) and a glass auxiliary material of 0.3BaO-B2O3-SiO2-0.3Nb2O5-0.15MnO-0.015La2O3. The mass ratio of the ceramic substrate to the glass auxiliary material is 98:2, and the particle size is ≤300nm. The preparation method is as follows: S1. Barium carbonate and titanium dioxide are added to water in a 1:1 molar ratio, and cerium nitrate is added at 0.003 times the molar amount of barium carbonate. The mixture is ball-milled until the particle size is less than 0.3 μm, spray-dried, and then sintered at 1380℃ for 5 h to obtain the ceramic main material. S2. Dissolve 2 parts of triethyl borate and 1 part of tetraethyl orthosilicate in a 70% aqueous ethanol solution. While stirring, add 0.3 parts of barium nitrate, 0.15 parts of manganese nitrate, and 0.015 parts of lanthanum nitrate sequentially until dissolved. Then add 12 parts of a 5 wt.% (NH4)3[NbO(C2O4)] aqueous solution (all parts are molar amounts). Continue stirring for 8 hours to form a sol. Aging at 60°C for 16 hours, followed by drying at 250°C. Finally, after ball milling and sieving, sinter at 600°C for 5 hours to obtain the glass additive. S3. The main ceramic material and the auxiliary glass material are mixed at a mass ratio of 98:2, and ball-milled with anhydrous ethanol until the particle size is less than 300nm. After drying and sieving, the barium titanate-based ceramic material is obtained.

[0060] Example 2 This embodiment provides a barium titanate-based ceramic material, comprising a Ce-doped BaTiO3 ceramic substrate (molar doping amount of 0.1%) and a glass auxiliary material of 0.25BaO-0.8B2O3-SiO2-0.25Nb2O5-0.1MnO-0.01La2O3, with a mass ratio of ceramic substrate to glass auxiliary material of 99:1 and a particle size ≤300nm. The preparation method is as follows: S1. Barium carbonate and titanium dioxide are added to water in a 1:1 molar ratio, and cerium nitrate is added at 0.001 times the molar amount of barium carbonate. The mixture is ball-milled until the particle size is less than 0.3 μm. After spray drying, it is sintered at 1350℃ for 6 hours to obtain the ceramic main material. S2. Dissolve 1.6 parts of tributyl borate and 1 part of isopropyl orthosilicate in a 60% aqueous ethanol solution. While stirring, add 0.25 parts of barium nitrate, 0.1 parts of manganese nitrate, and 0.01 parts of lanthanum nitrate sequentially until dissolved. Then add 9 parts of 5wt.% (NH4)3[NbO(C2O4)] aqueous solution (all parts are molar amounts). Continue stirring for 7 hours to form a sol. Aging at 50°C for 18 hours, followed by drying at 230°C. Finally, after ball milling and sieving, sinter at 500°C for 6 hours to obtain the glass additive. S3. The main ceramic material and the auxiliary glass material are mixed at a mass ratio of 99:1, and ball-milled with anhydrous ethanol until the particle size is less than 300nm. After drying and sieving, the barium titanate-based ceramic material is obtained.

[0061] Example 3 This embodiment provides a barium titanate-based ceramic material, comprising a Ce-doped BaTiO3 ceramic substrate (molar doping amount of 0.5%) and a glass auxiliary material of 0.35BaO-1.2B2O3-SiO2-0.35Nb2O5-0.2MnO-0.02La2O3, with a mass ratio of ceramic substrate to glass auxiliary material of 97:3 and a particle size ≤300nm. The preparation method is as follows: S1. Barium carbonate and titanium dioxide are added to water in a 1:1 molar ratio, and cerium nitrate is added at 0.005 times the molar amount of barium carbonate. The mixture is ball-milled until the particle size is less than 0.3 μm. After spray drying, it is sintered at 1450℃ for 4 hours to obtain the ceramic main material. S2. Dissolve 2.4 parts of tributyl borate and 1 part of butyl silicate in an 80% ethanol aqueous solution. While stirring, add 0.35 parts of barium nitrate, 0.2 parts of manganese nitrate, and 0.02 parts of lanthanum nitrate sequentially until dissolved. Then add 15 parts of 5wt.% (NH4)3[NbO(C2O4)] aqueous solution (all parts are molar amounts). Continue stirring for 9 hours to form a sol. Aging at 70℃ for 15 hours, followed by drying at 270℃. Finally, after ball milling and sieving, sinter at 700℃ for 4 hours to obtain the glass additive. S3. The main ceramic material and the auxiliary glass material are mixed at a mass ratio of 97:3, and ball-milled with anhydrous ethanol until the particle size is less than 300nm. After drying and sieving, the barium titanate-based ceramic material is obtained.

[0062] Example 4 The difference between this embodiment and Embodiment 1 is that Ce is not doped in the main ceramic material; and cerium nitrate is not added to S1. The remaining preparation methods and parameters are consistent with those in Example 1.

[0063] Example 5 The difference between this embodiment and Embodiment 1 is that La is doped into the main ceramic material; and in Embodiment S1, cerium nitrate is replaced with an equimolar amount of lanthanum nitrate. The remaining preparation methods and parameters are consistent with those in Example 1.

[0064] Example 6 The difference between this embodiment and Embodiment 1 is that the molar doping amount of Ce in the main ceramic material is 2%; and cerium nitrate is added in S1 at 0.02 times the molar amount of barium carbonate. The remaining preparation methods and parameters are consistent with those in Example 1.

[0065] Example 7 The difference between this embodiment and Embodiment 1 is that the glass additive is 0.3BaO-B2O3-SiO2-0.3Nb2O5-0.3MnO-0.1La2O3; and the amount of each raw material added is adjusted adaptively in S2. The remaining preparation methods and parameters are consistent with those in Example 1.

[0066] Example 8 The difference between this embodiment and Embodiment 1 is that the mass ratio of the main ceramic material to the auxiliary glass material is 90:10. The remaining preparation methods and parameters are consistent with those in Example 1.

[0067] Comparative Example 1 The difference between this comparative example and Example 1 is that the barium titanate-based ceramic material does not contain glass additives; S2 is not performed, and glass additives are not added in S3. The remaining preparation methods and parameters are consistent with those in Example 1.

[0068] Comparative Example 2 The difference between this comparative example and Example 1 is that the glass additive does not contain MnO; and no manganese nitrate is added to S2. The remaining preparation methods and parameters are consistent with those in Example 1.

[0069] Comparative Example 3 The difference between this comparative example and Example 1 is that Mn is doped in the ceramic main material and MnO is not contained in the glass auxiliary material; in S1, cerium nitrate is replaced with an equimolar amount of manganese nitrate. The remaining preparation methods and parameters are consistent with those in Example 1.

[0070] Comparative Example 4 The difference between this comparative example and Example 1 is that the glass additive does not contain Nb2O5; and no 5wt.% (NH4)3[NbO(C2O4)] aqueous solution is added to S2. The remaining preparation methods and parameters are consistent with those in Example 1.

[0071] Comparative Example 5 The difference between this comparative example and Example 1 is that in S1, glass additives (2 parts triethyl borate, 1 part tetraethyl orthosilicate, 0.3 parts barium nitrate, 0.15 parts manganese nitrate, 0.015 parts lanthanum nitrate, and 12 parts 5 wt.% (NH4)3[NbO(C2O4)] aqueous solution) are added simultaneously with cerium nitrate. The mass ratio of the ceramic main material to the glass additive is 98:2. S2 is not performed, and no batching is required in S3. The product obtained in S1 is directly ball-milled, dried, and sieved. The remaining preparation methods and parameters are consistent with those in Example 1.

[0072] Performance testing Take 100g of the barium titanate-based ceramic material prepared in Example 1, add 10g of PVB ethanol solution (10wt.%) to granulate, press the green blank using a 12mm mold, remove the binder at 280℃~450℃, and then sinter at 950℃ for 2h to obtain a ceramic sheet with a diameter of 10mm and a thickness of 2mm; print silver paste on the surface of the ceramic sheet, and sinter at 850℃ for 10min to obtain a ceramic capacitor silver sheet.

[0073] The barium titanate-based ceramic material prepared in Example 1 was replaced with the barium titanate-based ceramic material prepared in Examples 2-8 and Comparative Examples 1-5. The other preparation methods were the same, and the corresponding ceramic capacitor silver sheets were obtained.

[0074] The performance of the silver sheets of the ceramic capacitors mentioned above was tested, and the test results are shown in Table 1.

[0075] Table 1 As shown in Table 1, the barium titanate-based ceramic material provided by this invention, when applied to ceramic capacitors, exhibits high dielectric constant (2500~3000), low loss (0.22%~0.35%), and temperature coefficients that meet the X7P standard (X represents the lower limit temperature of -55℃, 7 represents the upper limit temperature of +125℃, and P represents the capacitance-temperature change rate within ±10%).

[0076] As can be seen from the comparison of the data of Example 1 and Comparative Examples 1-5 in Table 1, the ceramic main material and the glass auxiliary material in this invention must work synergistically and are indispensable. Among them, Nb2O5 and MnO are key components in the glass auxiliary material: if MnO is missing (Comparative Example 2) or Nb2O5 is missing (Comparative Example 3), the dielectric loss of the ceramic capacitor increases, and the temperature coefficient of the ceramic capacitor cannot meet the X7P characteristics (in Y5U, Y represents the lower limit temperature of -30℃, 5 represents the upper limit temperature of +85℃, and U is the capacitance-temperature change rate between +22% and -56%; in X7R, X represents the lower limit temperature of -55℃, 7 represents the upper limit temperature of +125℃, and R is the capacitance-temperature change rate within ±15%). Further comparison shows that if manganese nitrate and BaTiO3 are directly mixed and sintered, or if the raw materials are directly mixed and sintered (Comparative Examples 4-5), instead of being introduced through the glass auxiliary material, the capacitor performance will also decrease. This indicates that only by pre-placing the functional components in the glass auxiliary material can their effects be fully realized.

[0077] A comparison of the data from Examples 1 and 4-8 shows that, in this invention, by doping BaTiO3 with Ce and controlling the doping amount to 0.1%~0.5%, controlling the molar ratio of each component of the glass auxiliary material to (0.25~0.35):(0.8~1.2):1:(0.25~0.35):(0.1~0.2):(0.01~0.02), and controlling the mass ratio of the ceramic main material to the glass auxiliary material to (97~99):(1~3), the comprehensive performance of the ceramic material can be further improved.

[0078] 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 barium titanate-based ceramic material, characterized in that, The barium titanate-based ceramic material includes a ceramic main material and a glass auxiliary material. The ceramic main material includes BaTiO3, and the glass auxiliary material includes BaO, B2O3, SiO2, Nb2O5, MnO and La2O3.

2. The barium titanate-based ceramic material according to claim 1, characterized in that, The main ceramic material also includes Ce, and Ce is doped in the BaTiO3; Preferably, the amount of Ce doped in the BaTiO3 is 0.1 mol% to 0.5 mol%.

3. The barium titanate-based ceramic material according to claim 1 or 2, characterized in that, The molar ratio of BaO, B2O3, SiO2, Nb2O5, MnO and La2O3 is (0.25~0.35):(0.8~1.2):1:(0.25~0.35):(0.1~0.2):(0.01~0.02).

4. The barium titanate-based ceramic material according to any one of claims 1-3, characterized in that, The mass ratio of the main ceramic material to the auxiliary glass material is (97~99):(1~3); Preferably, the particle size of the barium titanate-based ceramic material is ≤300nm.

5. A method for preparing a barium titanate-based ceramic material as described in any one of claims 1-4, characterized in that, The preparation method includes: S1. Mix the first Ba source, Ti source and the first solvent and perform a first ball milling, and obtain the ceramic main material after a first sintering; S2. The second Ba source, B source, Si source, Nb source, Mn source, La source and the second solvent are mixed and stirred until they reach a sol state. After aging and sintering, glass additives are obtained. S3. Mix the ceramic main material and the glass auxiliary material and perform a second ball milling to obtain the barium titanate-based ceramic material.

6. The preparation method according to claim 5, characterized in that, Step S1: The first Ba source includes BaCO3; Preferably, the Ti source in step S1 includes TiO2; Preferably, in step S1, the molar ratio of the first Ba source to the Ti source is 1:(0.8~1.2); Preferably, in step S1, the first solvent includes water; Preferably, Ce salt is added during the first ball milling process in step S1; Preferably, the Ce salt comprises cerium nitrate; Preferably, in step S1, the first ball milling is performed until the particle size of the product is ≤0.3μm; Preferably, before the first sintering in step S1, the product of the first ball milling is spray-dried; Preferably, in step S1, the temperature of the first sintering is 1350℃~1450℃, and the time is 4h~6h.

7. The preparation method according to claim 5 or 6, characterized in that, The mixing steps described in step S2 are as follows: First, the B source and the Si source are dissolved in the second solvent. Under the second stirring condition, the Ba source, the Mn source and the La source are added in sequence. After dissolution, the Nb source is added. Preferably, in step S2, the second Ba source comprises a Ba salt, more preferably barium nitrate; Preferably, the Mn source in step S2 includes Mn salt, and more preferably manganese nitrate; Preferably, the La source in step S2 includes a La salt, and more preferably lanthanum nitrate; Preferably, the B source in step S2 includes a borate ester; Preferably, the Si source in step S2 includes a silicate ester; Preferably, the molar ratio of the B source and the Si source in step S2 is (1.8~2.2):1; Preferably, the Nb source in step S2 comprises an aqueous solution of (NH4)3[NbO(C2O4)]; Preferably, the mass concentration of the (NH4)3[NbO(C2O4)] aqueous solution is 4 wt.%~6 wt.%; Preferably, in step S2, the second solvent comprises ethanol and water.

8. The preparation method according to any one of claims 5-7, characterized in that, In step S2, the first stirring time is 7h~9h; Preferably, the aging temperature in step S2 is 50℃~70℃, and the time is 15h~18h; Preferably, before the second sintering in step S2, the aged product is sequentially dried, ball-milled, and sieved. Preferably, the drying temperature is 230℃~270℃; Preferably, in step S2, the second sintering temperature is 500℃~700℃ and the time is 4h~6h.

9. The preparation method according to any one of claims 5-8, characterized in that, Step S3: Add anhydrous ethanol during the second ball milling process; Preferably, in step S3, the second ball milling is performed until the particle size of the product is ≤300nm; Preferably, after the second ball milling in step S3, the ball milling product is dried and sieved sequentially to obtain the barium titanate-based ceramic material.

10. The application of a barium titanate-based ceramic material as described in any one of claims 1-4 in ceramic capacitors.

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