A pulse energy storage ceramic composition with high temperature stability and a preparation method thereof

Abstract

This invention provides a high-temperature stable pulse energy storage ceramic composition and its preparation method, relating to the field of pulse energy storage ceramic materials technology. The ceramic composition is based on Ba(Zr) x Ti 1‑x The main component is a perovskite compound (Bi2O3). In addition, it contains Bi as a first secondary component (Bi element) in the form of a composite of Bi2O3 and Bi2O3·nTiO2, as well as Ca, Sr, Mg, Mn, and Si elements. Its temperature coefficient of dielectric constant (TCC) meets -750±120ppm / ℃ over a wide temperature range of -55℃ to 125℃. The ceramic composition of this invention possesses high dielectric constant, low dielectric loss, high breakdown field strength, and a fine-grained structure, making it suitable for high-reliability pulse power capacitors.

Description

Technical Field

[0001] This invention relates to the field of pulse energy storage ceramic materials technology, specifically to a pulse energy storage ceramic composition with high-temperature stability and its preparation method. Background Technology

[0002] Pulse energy storage dielectric materials are key functional materials for achieving instantaneous high-density storage and release of electrical energy, and are the core foundation of modern pulse power capacitors. Based on their material form and composition, the main pulse energy storage dielectrics currently include polymer films, metallized paper dielectrics, and ceramic materials. Among these, ceramic dielectric materials stand out due to their extremely high insulation strength, excellent temperature and frequency stability, extremely long charge-discharge cycle life, and outstanding environmental reliability, such as resistance to damp heat and stable performance at high and low temperatures. Pulse power ceramic capacitors made from these materials have become indispensable core electronic components in fields with extremely high requirements for instantaneous power and reliability, such as ignition devices, laser pumps, electromagnetic emitters, high-frequency flashlights, power system relay protection, and oil and gas exploration.

[0003] However, while traditional pulsed power ceramic dielectrics offer good overall performance, the ever-expanding application scenarios, especially in extreme temperature environments such as aerospace, new energy vehicles, and underground resource exploration, present unprecedented demands for stable operation over a wide temperature range for pulsed power capacitors. Most existing pulsed energy storage ceramic materials exhibit significant drift in key parameters such as dielectric constant and dielectric loss at high temperatures, meaning they suffer from poor temperature stability (typically measured by the temperature coefficient of dielectric constant, TCC). This high-temperature instability leads to excessive capacitance fluctuations, decreased charge / discharge efficiency, and even thermal runaway and reliability risks during harsh temperature cycling, severely limiting their application in high-end equipment and harsh environments.

[0004] Therefore, the core challenge for those skilled in the art lies in how to significantly improve the stability of materials over a wide temperature range while ensuring that the materials possess fundamental electrical properties such as high dielectric constant, low dielectric loss, and high breakdown field strength. Traditional methods often sacrifice other properties when improving one, making synergistic optimization difficult. Therefore, an innovative composition and process design is urgently needed to develop novel pulse energy storage ceramic materials that combine excellent comprehensive electrical properties with superior high-temperature stability. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature stable pulse energy storage ceramic composition and its preparation method. While ensuring dielectric constant, loss, breakdown field strength and discharge current, it significantly improves temperature stability, meeting -750±120ppm / ℃ in the range of -55 to 125℃.

[0006] To achieve the above objectives, the present invention proposes the following technical solution:

[0007] A pulse ceramic composition with high-temperature stability, using Ba(Zr) x Ti 1-x The main component is O3 perovskite compound, of which 0.20 ≤ X ≤ 0.45. Based on 100 moles of Ba in the ceramic body, it also contains the following secondary components:

[0008] The first secondary component: Bi element, with a content of 5 to 20 moles, is added in the form of a composite of Bi2O3 and Bi2O3·nTiO2, where 1≤n≤6;

[0009] The second component: Ca element, with a content of 1 to 5 moles;

[0010] The third component: Sr element, with a content of 1 to 5 moles;

[0011] The fourth secondary component: Mg element, with a content of 0.1 to 2.0 moles;

[0012] The fifth secondary component: Mn element, with a content of 0.1 to 2.0 moles;

[0013] The sixth component: Si element, with a content of 0.2 to 5.0 moles, is added in the form of at least one glass system containing SiO2, namely ZnO-B2O3-SiO2, BaO-B2O3-SiO2, BaO-B2O3-Al2O3-SiO2, or BaO-CaO-SiO2.

[0014] As a preferred embodiment of the present invention, the molar ratio of Bi2O3 to Bi2O3·nTiO2 is 0.5 to 3.5.

[0015] As a preferred embodiment of the present invention, the second and third auxiliary components are added in the form of their carbonate compounds;

[0016] The fourth and fifth sub-components are added in their oxide form.

[0017] As a preferred embodiment of the present invention, the grain size of the ceramic composition is less than 300 nm.

[0018] The present invention also provides a method for preparing a pulsed ceramic composition with high-temperature stability, comprising the following steps:

[0019] (1) Weigh out the required amount of material for preparing Ba(Zr) according to the specified ratio. x Ti 1-xThe powders of BaCO3, ZrO2, and TiO2, the main components of the O3 perovskite compound, along with the various secondary components, are mixed and ground to obtain the first powder.

[0020] (2) After drying the first powder, calcine it at 800-1000℃ for 1-4 hours to obtain the second powder;

[0021] (3) The second powder is dried, ground and granulated to obtain the third granules;

[0022] (4) The third granule is dry-pressed to obtain a shaped blank;

[0023] (5) Perform a debinding process on the molded blank to obtain a rough blank;

[0024] (6) The blank is held at a sintering temperature of 1050-1150°C for 1-4 hours, and the ceramic body of the ceramic composition is obtained after sintering.

[0025] As a preferred embodiment of the present invention, the particle size D50 of the first powder is 0.2 to 1.0 μm.

[0026] As a preferred embodiment of the present invention, the particle size D50 of the second powder after grinding is 0.2 to 0.5 μm.

[0027] As a preferred technical solution of the present invention, in step (3), the granulation method is manual granulation or spray granulation.

[0028] As a preferred embodiment of the present invention, the adhesive removal process includes:

[0029] First, keep the temperature at 300℃ for 5 hours, then raise the temperature to 600℃ at a rate of less than 5℃ / min and keep it at that temperature for 2 hours.

[0030] As can be seen from the above technical solutions, the technical solution of the present invention provides a high-temperature stable pulse energy storage ceramic composition and its preparation method, which has the following beneficial effects compared with the prior art:

[0031] 1. This invention, through the composition design of co-doping Bi2O3 and Bi2O3·nTiO2 with Ca, Mg, Mn and Bi multi-element ions, significantly suppresses the temperature drift of the dielectric constant. The obtained ceramic material has a stable temperature coefficient of dielectric constant (TCC) of -750±120ppm / ℃ in a wide temperature range of -55℃ to 125℃, which fully meets the stringent requirements of extreme environments for the temperature stability of electronic components, and fundamentally solves the high-temperature application reliability problem mentioned in the background art.

[0032] 2. While achieving excellent temperature stability, the material of this invention maintains a high dielectric constant, extremely low dielectric loss, high insulation resistance, and high breakdown field strength. This synergistic optimization of performance ensures that the capacitor can stably store and release energy under high voltage and rapid pulse operating conditions, while also maintaining a long lifespan and high reliability.

[0033] 3. Through the sintering-aiding effect of the components and the SiO2-containing glass system, low-temperature sintering and significant grain refinement and homogenization were achieved. Finer grains facilitate the preparation of thinner and denser dielectric layers, directly driving the development of multilayer ceramic capacitors towards thinner, smaller, and higher capacitance.

[0034] 4. In terms of composition, this invention effectively suppresses abnormal grain growth during sintering by introducing elements such as Mg, Mn, and Bi. In terms of process, precise control of the raw material powder and the grinding particle size after calcination provides a precursor with uniform size and high activity. The synergistic effect of the formulation and process ensures that the grain size of the final ceramic body is effectively controlled below 300 nm and is uniformly distributed. This ultrafine and uniform microstructure provides the foundation for the material to achieve high breakdown field strength and high reliability.

[0035] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0036] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0037] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0038] Figure 1 This is a comparison curve of the TCC of the ceramic composition of the present invention with that of a comparative example;

[0039] Figure 2 This is a microstructure diagram of the particle size of the second powder used in the preparation of ceramic compositions according to the present invention.

[0040] Figure 3 Microstructure diagrams of powder particle size used to prepare ceramic materials are shown for comparison. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0042] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, wholes, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or sets thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] Description of the composition: The ceramic composition claimed in this invention is defined by the molar proportions of key components and / or key elements in the final ceramic body obtained after sintering. In specific embodiments and examples, to clearly illustrate this composition, the raw material ratios of the final composition (in molar parts of the raw material compounds) are first given, along with the calculated molar ratios of compounds and / or elements corresponding to the final ceramic body (e.g., based on 100 molar parts of Ba in the ceramic body). Those skilled in the art will understand that the raw materials undergo chemical reactions, volatilization, etc., during sintering, but through the preparation method of this invention, the raw material ratios can stably obtain a ceramic body with the following final component and / or elemental composition.

[0044] The present invention provides a high-temperature stable pulse energy storage ceramic composition, using Ba(Zr) x Ti 1-xO3 is a perovskite compound as the main component and is also the main crystalline phase of the ceramic body. Among them, 0.20≤X≤0.45. By controlling the value of X within this range, it is ensured that the ceramic material is in the paraelectric phase state throughout the entire working temperature range, including room temperature, thus laying the physical basis for its ultra-high temperature stability.

[0045] In the ABO3 main crystal phase of the perovskite structure of this invention, the B site is ZrTi, and the A site, when undoped with Ca and Sr, is a single element Ba; after doping, it is actually a BaCaSr composite element. Furthermore, in some specific embodiments of this invention, Bi may also partially enter the A site. Therefore, in the formulation design, the ratio of the total molar number of all elements expected to enter the A site of the main crystal phase (including Ba, Ca, Sr, and Bi) to the total molar number of all elements expected to enter the B site (including Zr and Ti) should be controlled within a range close to 1.00. This design ensures the stability of the perovskite crystal structure and provides space for fine-tuning through non-stoichiometric ratios to optimize dielectric constant, insulation properties, etc. In the raw material ratio design of some specific embodiments of this invention, the total molar ratio of A-site elements to B-site elements in the raw materials is preferably controlled between 0.90 and 1.10.

[0046] Assuming the Ba element in the ceramic body is 100 molar parts, the ceramic composition also contains the following secondary components:

[0047] The first secondary component is Bi element, with a content of 5-20 moles, wherein Bi element is added in the form of a composite of Bi2O3 and Bi2O3·nTiO2, where 1≤n≤6, and n is preferably 1.5. When n=1.5, Bi2O3·1.5TiO2 can be regarded as Bi4Ti3O 12 Or a simplified representation similar to layered perovskite phases. Such structures can form a good structural fit with the host crystal phase at high temperatures, which can promote the entry of Bi into the lattice A sites of the host crystal phase in a controllable manner, rather than forming a discrete insulating second phase, thereby more effectively introducing defect dipoles and enhancing local polarization.

[0048] The molar ratio of Bi₂O₃ to Bi₂O₃·nTiO₂ in this invention is 0.5–3.5. Co-doping with Bi₂O₃ and Bi₂O₃·nTiO₂ can, on the one hand, suppress the volatilization of Bi₂O₃, synergistically and effectively reduce the sintering temperature and increase density; on the other hand, Bi… 3+ After entering the lattice, Bi introduces defect dipoles, generating additional polarization and increasing the dielectric constant; in addition, Bi 3+The introduction of Bi transforms the original macrodomains into microdomains or polar nanodomains, which are more sensitive to the turning response under an electric field, thus improving the macroscopic polarization response and thereby increasing the dielectric constant. In the constructed strongly disordered, wide-temperature-range paraelectric lattice environment, the highly disordered matrix coupling of these polar nanodomains is tighter, and the dependence of their turning activation and relaxation behavior on temperature is significantly weakened. Therefore, when the temperature changes, the additional polarization energy contributed by Bi remains relatively stable, avoiding the drastic fluctuations in dielectric constant caused by local polarization fluctuations.

[0049] The second auxiliary component is Ca, with a content of 1-5 moles. The Ca source includes, but is not limited to, calcium carbonate, calcium oxide, calcium hydroxide, or mixtures thereof, preferably added in the form of CaCO3. In this invention, Ca synergizes with Ba in the main component and with Sr in the auxiliary component, utilizing the difference in ionic radii at the A-sites of the perovskite structure (BaCaSr) to create strong compositional fluctuations. This effectively suppresses the formation of long-range ferroelectric order, ensuring that the ceramic material is in a low-loss paraelectric phase at room temperature, providing a stable platform for the polarization enhancement of Bi-based doping. Simultaneously, calcium ions, together with the subsequent glass system, promote sintering densification.

[0050] The third component is Sr, with a content of 1 to 5 moles, preferably added in the form of SrCO3.

[0051] The fourth component is Mg, with a content of 0.1 to 2.0 moles. The source of Mg includes, but is not limited to, at least one of MgO, MgCO3, and Mg(OH)2, with MgO being preferred.

[0052] The fifth component is Mn element, with a content of 0.1 to 2.0 moles, preferably at least one of MnO, MnCO3, and Mn(OH)2, with MnO being preferred.

[0053] This invention effectively suppresses abnormal grain growth during sintering by co-doping with Mg, Mn, and Bi, and promotes the formation of a uniform and fine grain structure during the sintering process. The fine grain structure means more insulating grain boundaries, which is the key to obtaining a high breakdown field strength. At the same time, it can balance the possible charge imbalance and improve the insulation resistance and breakdown voltage.

[0054] The sixth component: Si element, with a content of 0.2–5.0 moles; preferably added in the form of at least one glass system containing SiO2, namely ZnO-B2O3-SiO2 (zinc borosilicate glass system), BaO-B2O3-SiO2 (barium borosilicate glass system), BaO-B2O3-Al2O3-SiO2 (barium borosilicate aluminum silicate glass system), or BaO-CaO-SiO2 (barium calcium silicate glass system). During sintering, the glass system transforms into a liquid phase that wets the ceramic particles, helping to lower the sintering temperature. It ultimately deposits at the grain boundaries, further improving the grain boundary insulation performance and the overall density of the ceramic material, synergistically ensuring high voltage withstand reliability in conjunction with grain refinement.

[0055] This invention first establishes the foundation for low-loss and high-field-strength stability of ceramic materials through a BZT paraelectric substrate and a high-calcium stabilization strategy. Second, through unique Bi-based composite doping, a strong local polarization source is implanted on the paraelectric substrate, achieving a significant increase in dielectric constant without introducing significant domain wall motion losses. Finally, through the synergy of Mg and Mn doping and Si-containing glass phase, the process achieves control over low-temperature sintering and fine-grained, highly dense microstructure, thereby ensuring excellent breakdown strength and insulation resistance even at high dielectric constants.

[0056] This invention also provides a method for preparing a high dielectric constant pulse energy storage ceramic composition, specifically comprising the following steps:

[0057] (1) The preparation of Ba(Zr) x Ti 1-x The three compound powders of BaCO3, ZrO2 and TiO2, which are the main components of the O3 perovskite type compound, and the compound containing each auxiliary element are weighed according to the molar parts, and thoroughly mixed in a ball mill to obtain a uniform first powder. The particle size D50 of the first powder is preferably 0.2 to 1.0 μm.

[0058] (2) Dry the first powder and then calcine it at 800-1000℃ for 1-4 hours to obtain the calcined second powder.

[0059] Through steps (1) and (2), BaCO3, ZrO2, and TiO2 will spontaneously react to generate Ba(ZrO2) during sintering. x Ti 1-x O3 is the main component of the calcium-titanium compound, which is also the main crystalline phase of the ceramic composition of the present invention.

[0060] (3) The second powder is dried and ground again until the particle size D50 is 0.2-0.5μm, and then granulated to obtain the third granules. The grinding method can be ball milling or sand milling. By miniaturizing the particle size of ceramic powder, the material is made thin and highly dense.

[0061] By miniaturizing the raw material powder particle size and controlling the sintering process, the powder, after high-temperature sintering, will form a uniform and fine microcrystalline structure. (Refer to...) Figure 2 and Figure 3 , Figure 2 The image shows a micrograph of the particle size of the second powder used to prepare the ceramic composition according to an embodiment of the present invention, wherein the maximum particle size is less than 300 nm. This transformation from submicron-level precursor powder to submicron-level sintered crystal grains is the key to achieving high density and high breakdown field strength in the ceramic material of the present invention. Figure 3 The micrographs shown are for the particle size distribution of powder used in the preparation of ceramic materials. The average particle size is approximately 600 nm, which is significantly larger than the powder size in the embodiments of this invention. This relatively coarse powder will have adverse effects on the grain structure formed after sintering, including but not limited to: a reduced proportion of insulating grain boundaries, which limits the improvement of the overall breakdown field strength of the material; insufficient densification, as coarse grains are often accompanied by abnormal grain growth during the sintering process, which may leave more intragranular or grain boundary pores, impairing the density and mechanical strength of the material; and it is not conducive to the thinning of dielectric layers. For example, when preparing ultrathin MLCC dielectric layers, large grain sizes can easily lead to poor uniformity and increased defects in the dielectric layer, becoming a hidden danger.

[0062] Granulation is a crucial and routine pretreatment step in the preparation of high-performance ceramic components, particularly for dry pressing. By adding a small amount of organic binder, fine ceramic powder particles are formed into pseudo-agglomerates with a certain mechanical strength. For example, the third granule obtained after granulation can achieve rapid and uniform filling of the mold cavity in subsequent dry pressing, thereby obtaining a molded green body with uniform density. In some specific embodiments of the present invention, there are at least two granulation methods. Specifically, one is manual granulation, where the second powder is dried and sieved, and then 5wt% PVB or 5wt% PVA glue or other organic binder is added, followed by manual granulation to obtain the third granule; the other is PVA spray granulation, with a duration of 10s to 120s.

[0063] (4) The third granule is dry-pressed to obtain a preform, wherein the preferred pressing pressure is 1T / cm. 2 (1 ton-force / square centimeter represents the pressure required to act on each square centimeter of the billet's projected area, which is 1 ton-force), where 1 T / cm 2 It is approximately equal to 98.0665 MPa (megapascals). For ease of calculation and memorization, it is often approximated to 100 MPa in engineering practice. Therefore, the molding pressure of the present invention can preferably be 100 MPa.

[0064] (5) The formed green body is subjected to a debinding process to obtain a rough green body. Specifically, air debinding is used, and the body is held at 300℃ for 5 hours, followed by a programmed temperature increase to 600℃ and a holding time of 2 hours, with a heating rate of less than 5℃ / min. Through the debinding process, the organic binder is completely removed, the pseudo-agglomerates disintegrate, and the green body is restored to a loose network structure composed of the original submicron-sized powder particles. Finally, during the sintering process, mass transfer is based on these submicron-sized initial particles, thereby achieving densification and grain growth.

[0065] (6) The blank is kept at a sintering temperature of 1050-1150°C for 1-4 hours. After sintering, the ceramic body material of the ceramic composition is obtained.

[0066] No inert gas protection is required during sintering; it can be sintered in air, making it suitable for mass production. Too low a sintering temperature will result in under-sintering, while too high a temperature will result in over-sintering, leading to performance degradation.

[0067] This invention reduces the sintering temperature by approximately 60°C by using Bi-based composite co-doping with a glass system for sintering assistance. Furthermore, it achieves this by pre-preparing powders with extremely small particle sizes (see reference). Figure 1 This helps to make the grains in the ceramic composition uniform and fine, with a maximum particle size of <300nm, which is beneficial for the thinning and high-capacity of MLCCs.

[0068] (7) Perform performance tests on the ceramic material.

[0069] In some specific embodiments of the present invention, the performance test descriptions or effect descriptions related to dielectric constant, dielectric loss, resistance, TCC (-55℃ / 125℃), etc., are all conducted in accordance with industry-standard methods for relevant electrical performance testing.

[0070] Dielectric performance testing, dielectric loss testing, and insulation impedance testing: A commercially available dielectric ceramic dielectric constant tester, such as the TH2838A device, is used to test dielectric loss and dielectric constant; a commercially available insulation resistance tester, such as the TH2690A device, is used to measure insulation impedance values.

[0071] The TCC test uses commercially available TCC testing equipment, such as the TZDM-200-300 device; low temperature is controlled by liquid nitrogen, and high temperature is controlled by electric heating to test the TCC curve of the ceramic composition sample.

[0072] To make the technical solution, superior performance, and implementation of the present invention clearer, the following detailed description is provided through specific embodiments and comparative examples. In Examples 1-3 of the present invention, the ingredients were formulated according to the aforementioned component range, and ceramic composition samples were prepared strictly following the described preparation method. Simultaneously, a representative commercially available product of the same type (Ferro LF451C model from the USA) was selected as a comparative example, and compared under the same specifications and testing conditions to objectively verify the significant improvements in wide-temperature stability, dielectric properties, and microstructure of the ceramic composition described in the present invention. The specific raw material ratios for each embodiment are detailed in Table 1, and the corresponding material performance test results are summarized in Table 3.

[0073] Table 1. Molar proportions of each raw material component in Examples 1-3 (in terms of compound molar proportions)

[0074]

[0075] Based on the raw material ratios in Table 1, assuming all raw material elements are completely transferred into the ceramic body, and calculated with all Ba elements in the final ceramic body normalized to 100 moles, the calculation results show that the ceramic body with the composition defined in this invention can be obtained from the raw material ratios. The data from Example 1 serves as a detailed example of the calculation process, where n=1.5 in Bi₂O₃·nTiO₂; in the BaO-B₂O₃-SiO₂ glass system, since B is not a critical element, it can be ignored, and its specific chemical composition is assumed to be BaO·SiO₂. The specific calculation process is shown in Table 2 below:

[0076] Table 2 Calculation process of each key element in Example 1

[0077]

[0078] Calculation of the main crystalline phase Ba(Zr) x Ti 1-x The X value in the chemical formula of O3 perovskite compounds:

[0079] X=Zr / (Zr+Ti)=35 / (35+75)≈0.318.

[0080] Normalize each component element to "based on 100 moles of Ba in the ceramic body", and assume that all Ba in the final ceramic composition comes from the total Ba input. Then the normalization factor is:

[0081] Normalization factor = 100 / (total Ba content) = 100 / 100 = 1.

[0082] Molar fractions of each component element:

[0083] Bi: 8 × 1 = 8 moles;

[0084] Ca: 1.2 × 1 = 1.2 moles;

[0085] Sr: 2.3 × 1 = 2.3 moles;

[0086] Mg: 0.25 × 1 = 0.25 molar parts;

[0087] Si: 1.7 × 1 = 1.7 moles;

[0088] Mn: 1.41 × 1 = 1.41 moles.

[0089] For BaO-CaO-SiO2 in Example 2, it is assumed that its composition is (Ba 0.6 Ca 0.4 SiO3; In addition, n in Bi2O3·1.5TiO2 in Examples 2 and 3 is calculated to be 1.5.

[0090] It is important to note that in this embodiment of the invention, the total amount of Ba is only included in the Ba in the main raw material BaCO3, and not in the Ba in the glass system. The main reason is that the Ba in the glass system, as a sintering aid, mainly exists in the grain boundary glass phase and does not participate in the formation of the main crystalline phase. The total amount of Ti is only included in the Ti in the main raw material TiO2, and not in Bi2O3·1.5TiO2, because Bi2O3·1.5TiO2 is added as a composite source of Bi, and its Ti element forms a stable structure with Bi in the composite, mainly used to regulate the doping behavior of Bi rather than contributing to the Ti sites of the main crystalline phase. The total amount of Ca is only included in the Ca in CaCO3, and not in the Ca in the glass system, because the glass system, as a fluxing component, mainly promotes sintering densification rather than entering the A sites of the main crystalline phase.

[0091] Table 3 Material properties of Examples 1-3 and comparative examples

[0092]

[0093] In Table 3, ε r Tanδ represents the dielectric constant, Tanδ represents the dielectric loss, -55℃ (%) represents the TCC of the material at -55℃, which is the temperature coefficient of dielectric constant, indicating the relationship between the dielectric constant and temperature, 125℃ (%) represents the TCC of the material at 125℃; IR represents the insulation resistance.

[0094] The comparative example is the Ferro LF451C product, and the sample specifications tested are consistent with those of Examples 1 to 3 of this invention.

[0095] As can be seen from Table 3, the ceramic composition materials prepared in Examples 1-3 of this invention exhibit a series of synergistically optimized excellent properties, especially achieving breakthrough progress in high-temperature stability, as detailed below:

[0096] The TCC values ​​of the example samples at the two extreme temperatures of -55°C and 125°C (approximately 4% and approximately -11%, respectively) were significantly better than those of the comparative samples (16.5% and -20.2%). Figure 1 As can be seen, within the operating range of -55℃ to 125℃, the TCC variation range of the present invention is approximately -11% to 4%, and the dielectric constant temperature coefficient (TCC) is stable at -750±120ppm / ℃, which is much more stable than the comparative example of -20% to 16%. This indicates that the dielectric constant of the material of the present invention changes extremely smoothly over a wide temperature range. This performance is mainly attributed to the unique multi-element synergistic doping system of the present invention.

[0097] This invention controls the Zr content (X value) to be between 0.2 and 0.45, and introduces Sr and Ca to perform composite substitution at the A-site (Ba site), transforming the original single-element A-site (Ba) into a composite element A-site (BaCaSr). It also partially substitutes Zr at the B-site (Ti site), transforming the original single-element B-site (Ti) into a composite element B-site (ZrTi). This introduces ions with different ionic radii into the crystal lattice points, for example, Ba... 2+ Ca 2+ Sr 2+ Of the three ions, Ba 2+ Maximum, Ca 2+ Minimum; Ti 4+ Zr 4+ Of the two, the ionic radius of Zr 4+ >Ti 4+ These ions are randomly distributed in the crystal lattice, producing strong "compositional fluctuations," which effectively suppress the formation of long-range ferroelectric order and enable the ceramic material to maintain a stable paraelectric phase over a wide temperature range.

[0098] While achieving ultra-high temperature stability, the key electrical parameters of the materials in the examples are all superior to those in the comparative examples. Among them, the excellent insulation resistance and breakdown field strength are due to the grain boundary modification effect of elements such as magnesium and manganese, as well as the uniform distribution of the glass phase at the grain boundaries. These elements together purify and strengthen the grain boundaries, hindering charge migration and the initiation of electrical trees.

[0099] The sintering temperature of the embodiment was significantly lower than that of the comparative example by approximately 20–60 °C. This is mainly due to the fusion-enhancing effect of Bi-based co-doped glass systems, which form a continuous and stable insulating layer during sintering. This glass phase not only increases the breakdown field strength, but more importantly, it acts as a buffer layer and charge trap, stabilizing the potential at grain boundaries and reducing the redistribution and migration of interfacial charges during temperature changes, thereby further mitigating the temperature drift of macroscopic dielectric properties.

[0100] The core design of this invention lies in fundamentally controlling the phase state and microstructure of the material through the synergistic substitution and doping of multiple elements in the perovskite crystal structure, thereby achieving the target performance. Specifically:

[0101] This invention uses Sr and Ca to partially replace the main component Ba(Zr) x Ti 1-x The A-site (Ba site) of O3 is replaced by Zr at the B-site (Ti site). Since these ions have different radii, for example, the A-site ion (Ba...) 2+ Ca 2+ 、Sr 2+ ) radius, Ba 2+ Maximum, Ca 2+ Minimum; B-site ion (Ti 4+ Zr 4+ Radius Zr 4+ >Ti 4+ These components are randomly distributed in the crystal lattice, producing strong "compositional fluctuations." This chemically disordered compositional fluctuation not only further destroys any remaining ferroelectric order in the micro-regions, but also makes the free energy curve of the crystal lattice flatten over a wide temperature range, greatly reducing the temperature sensitivity of the dielectric constant. In other words, temperature changes are unlikely to induce significant changes in the polarization state, thus directly resulting in excellent TCC performance.

[0102] Use Zr in position B. 4+ Partially replaces Ti 4+ This is particularly crucial. Because the Zr-O bond length is longer and the covalentity is weaker than the Ti-O bond, Zr... 4+ The non-central displacement capability in the BO6 oxygen octahedron is significantly reduced, thereby weakening the polarization-related oxygen octahedral distortion in the perovskite structure and helping to suppress long-range ferroelectric order. This invention achieves a higher proportion of Zr within the range of 0.20 ≤ X ≤ 0.45. 4+ For Ti 4 The substitution of oxygen enhances the structural rigidity of the BO6 oxygen octahedron, greatly suppressing the cooperative distortion of the oxygen octahedron required for spontaneous polarization. This results in the complete "broadening" and suppression of the ferroelectric phase transition characteristic (Curie peak) of the ceramic material to a temperature range far below -55℃. Therefore, within the entire target temperature range (-55℃ to 125℃), the ceramic material is essentially in a paraelectric state without structural phase transition, which is the physical basis for achieving ultra-high temperature stability.

[0103] The aforementioned lattice-level design directly corresponds to the excellent TCC performance shown in Table 3. Simultaneously, the stable paraelectric phase also implies lower domain wall friction loss, which corresponds to extremely low dielectric loss. The co-doping of magnesium and manganese ions continues to suppress grain growth and refine the grain structure; furthermore, as charge compensators, they neutralize charged defects such as oxygen vacancies that may arise from ion substitution. Stable grain boundaries and lower defect concentration reduce the increase in conductivity of the ceramic material at high temperatures, while maintaining excellent insulation resistance, indirectly supporting the stability of dielectric properties at high temperatures.

[0104] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A high-temperature stable pulse energy storage ceramic composition, characterized in that, Take Ba(Zr x Ti 1-x The main component is O3 perovskite compound, of which 0.20 ≤ X ≤ 0.

45. Based on 100 moles of Ba in the ceramic body, it also contains the following secondary components: The first secondary component: Bi element, with a content of 5-20 moles, is added in the form of a composite of Bi2O3 and Bi2O3·nTiO2, where 1≤n≤6; The second component: Ca element, with a content of 1 to 5 moles; The third component: Sr element, with a content of 1 to 5 moles; The fourth secondary component: Mg element, with a content of 0.1 to 2.0 moles; The fifth secondary component: Mn element, with a content of 0.1 to 2.0 moles; The sixth component: Si element, with a content of 0.2 to 5.0 moles, is added in the form of at least one glass system containing SiO2, namely ZnO-B2O3-SiO2, BaO-B2O3-SiO2, BaO-B2O3-Al2O3-SiO2, or BaO-CaO-SiO2. The composition is also prepared by the following steps: (1) Weigh out the required amount of material for preparing Ba(Zr) according to the specified ratio. x Ti 1-x The powders of BaCO3, ZrO2, and TiO2, the main components of the O3 perovskite compound, along with the various secondary components, are mixed and ground to obtain the first powder. (2) After drying the first powder, calcine it at 800-1000℃ for 1-4 hours to obtain the second powder; (3) The second powder is dried, ground and granulated to obtain the third granules; (4) The third granule is dry-pressed to obtain a shaped blank; (5) Perform a debinding process on the molded blank to obtain a rough blank; (6) The blank is held at a sintering temperature of 1050-1150°C for 1-4 hours, and the ceramic body of the ceramic composition is obtained after sintering.

2. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The molar ratio of Bi2O3 to Bi2O3·nTiO2 is 0.5 to 3.

5.

3. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The second and third sub-components are added in the form of their carbonate compounds; The fourth and fifth sub-components are added in their oxide form.

4. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The ceramic composition has a grain size of less than 300 nm.

5. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The particle size D50 of the first powder is 0.2 to 1.0 μm.

6. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The particle size D50 of the second powder after grinding is 0.2 to 0.5 μm.

7. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, In step (3), the granulation method is manual granulation or spray granulation.

8. The high-temperature stable pulse energy storage ceramic composition according to claim 1, characterized in that, The adhesive removal process includes: First, keep the temperature at 300℃ for 5 hours, then raise the temperature to 600℃ at a rate of less than 5℃ / min and keep it at that temperature for 2 hours.

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