High-temperature-stability high-dielectric-constant ceramic composition and preparation method thereof
By introducing high-purity barium titanate and specific dopants into the ceramic composition, combined with advanced preparation processes, the shortcomings of traditional ceramic compositions in dielectric properties and temperature stability have been overcome, resulting in ceramic materials with high dielectric constant, low loss, and wide temperature range stability, suitable for high-frequency electronic devices and microwave communications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KUNSHAN QINGYUAN ELECTRONIC TECHNOLOGY CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional high dielectric constant ceramic compositions have shortcomings in dielectric properties and temperature stability, making it difficult to meet the requirements of high-frequency, miniaturized and high-performance electronic devices. Moreover, the preparation process is complex and energy-intensive, which limits large-scale production and application.
Using high-purity barium titanate as the main component, combined with rare earth, alkaline earth and transition metal oxide doping, and through processes such as cryogenic ball milling, microwave-assisted pre-firing, multi-stage sintering and annealing, the composition and microstructure of ceramics are optimized to prepare ceramic compositions with high dielectric constant, low loss and high temperature stability.
It significantly improves dielectric constant, reduces dielectric loss, enhances temperature stability and resistivity, increases breakdown strength, optimizes microstructure, and reduces production costs, making it suitable for applications in high-frequency electronic devices and microwave communications.
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Figure CN121850646A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electronic materials technology, and more specifically, relates to a high-temperature-stability, high-dielectric-constant ceramic composition and its preparation method. Background Technology
[0002] In today's era of rapid technological advancement, electronic devices are constantly moving towards higher frequencies, smaller sizes, and higher performance, which places increasingly higher demands on dielectric materials, which are key components. In fields such as high-frequency electronic devices, large-capacity capacitors, and microwave communications, ceramic materials have attracted significant attention due to their excellent dielectric properties.
[0003] However, traditional high-dielectric-constant ceramic compositions have revealed many shortcomings in practical applications. On the one hand, their dielectric constant often fails to meet the high-performance requirements of modern electronic devices, limiting further miniaturization and functional enhancement of electronic devices. On the other hand, poor temperature stability is a significant drawback of traditional ceramic compositions; their dielectric properties are prone to large fluctuations under different temperature environments, seriously affecting the reliability and stability of electronic devices.
[0004] Traditional methods for ceramic preparation have several drawbacks. Insufficiently refined raw material pretreatment leads to uneven particle size and composition, thus affecting ceramic properties. Simple forming methods make it difficult to achieve ideal shapes and sizes. Sintering processes are typically limited and cannot control the microstructure and properties of the ceramic. Inaccurate annealing treatments fail to effectively eliminate internal stress, resulting in unstable electrical properties.
[0005] Furthermore, traditional preparation processes are often complex and energy-intensive, increasing production costs and limiting large-scale production and widespread application. Due to these limitations, developing novel ceramic compositions and their preparation methods with high dielectric constants, high temperature stability, and simple and efficient processes is of paramount importance to meet the ever-evolving needs of the electronics technology field. Summary of the Invention
[0006] To address the aforementioned technical problems, this invention provides a high-temperature-stability, high-dielectric-constant ceramic composition and its preparation method, thereby resolving the problems described above.
[0007] A high-temperature-stability ceramic composition with high dielectric constant includes a main component and dopant components. The main component is high-purity, uniformly sized barium titanate (BaTiO3) with high dielectric constant properties, accounting for 60%-70% of the total mass of the ceramic composition. The dopant components include 5%-8% rare earth element oxides, 5%-8% alkaline earth metal oxides, and 3%-5% transition metal oxides, accounting for 100% of the total mass. The balance is functional additives (rare earth element oxides, alkaline earth metal oxides, and transition metal oxides).
[0008] Preferably, the rare earth element oxides are lanthanum oxide (La₂O₃) and neodymium oxide (Nd₂O₃), the alkaline earth metal oxides are magnesium oxide (MgO) and calcium oxide (CaO), and the transition metal oxides are copper oxide (CuO) and manganese oxide (MnO₂). Lanthanum oxide (La₂O₃) and neodymium oxide (Nd₂O₃), as rare earth element oxides, can improve the crystal structure of ceramics, help increase the Curie temperature, thereby enhancing the temperature stability of the ceramic composition, refining the grains, improving the density and uniformity of ceramics, and thus improving the dielectric properties. Magnesium oxide (MgO) and calcium oxide (CaO), as alkaline earth metal oxides, regulate the sintering performance of ceramics, lower the sintering temperature, promote the densification process of ceramics, optimize the dielectric properties, and enable the ceramics to maintain a stable dielectric constant at different frequencies. Copper oxide (CuO) and manganese oxide (MnO₂), as transition metal oxides, improve the microstructure of ceramics, reduce internal defects, improve the density of ceramics, increase the resistivity and breakdown strength of ceramics, and enhance their electrical properties and stability.
[0009] A method for preparing a high-temperature-stability, high-dielectric-constant ceramic composition includes the following steps: S1: Raw material pretreatment: The particles are refined by cryogenic ball milling technology, and microwave-assisted heating technology is introduced in the pre-calcination stage to control the temperature, time and power of pre-calcination in order to remove volatile components; S2: Molding: The granulated powder is placed into a mold of a specific size and dry-pressed under pressure to obtain a blank of a specific shape and size; S3: Debinding and Pre-firing: The formed green body is placed in a box-type resistance furnace and heated to a specific temperature at a slow heating rate to debind the material. The temperature is then increased to perform pre-firing, so that the raw materials undergo a preliminary solid-phase reaction to form a ceramic precursor. S4: Sintering: The pre-fired ceramic precursor is placed in a high-temperature tube furnace and heated to a high temperature at an appropriate heating rate under a specific atmosphere and held for a certain time to allow the ceramic to be fully sintered and form a dense ceramic body. S5: Annealing treatment: After sintering, the ceramic body is quickly transferred to another box-type resistance furnace, annealed at a specific temperature and held for a certain time, and then cooled to room temperature with the furnace. S6: Surface treatment and electrode preparation: Pulse annealing and vacuum evaporation are used to prepare silver electrodes of a specific thickness on the upper and lower surfaces of the ceramic body.
[0010] Preferably, in the cryogenic ball milling technology, the milling jar is placed in a low-temperature environment of -50°C to -20°C.
[0011] Preferably, the heating rate of the glue removal process is 1-3℃ / min, and the glue removal temperature is 400-500℃.
[0012] Preferably, the pre-firing temperature is 700-900℃ and the pre-firing time is 2-4 hours.
[0013] Preferably, the sintering heating rate is 5-10℃ / min, the sintering temperature is 1200-1400℃, the holding time is 2-4 hours, and the sintering atmosphere is a mixture of nitrogen and oxygen, wherein the volume ratio of nitrogen to oxygen is 3:1.
[0014] Preferably, the annealing temperature is 500-700℃ and the holding time is 1-2 hours.
[0015] Preferably, the thickness of the silver electrode prepared by vacuum evaporation is 1-3 micrometers, and the dielectric constant of the ceramic composition prepared by the method changes by ±3% in the temperature range of -70℃ to 180℃.
[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Significantly Improved Dielectric Constant of Ceramic Composition: This invention achieves a significant improvement in the dielectric constant of the ceramic composition by selecting high-purity, uniformly sized barium titanate with high dielectric constant as the main component, and combining it with specific dopant components, such as rare earth element oxides, alkaline earth metal oxides, and transition metal oxides. Taking Example 1 as an example, its dielectric constant reaches 3500, compared to only 2000 in the comparative example, demonstrating a significant improvement. This allows for the use of smaller ceramic materials in electronic devices to achieve the same capacitance value, contributing to the miniaturization and high performance of electronic devices.
[0017] 2. Significantly Reduced Dielectric Loss: In this invention, by optimizing the composition and microstructure of the ceramic, dielectric loss is effectively reduced. For example, the dielectric loss in Example 1 is only 0.008, while the comparative example is as high as 0.025. Low dielectric loss means reduced energy loss during energy transmission and storage, thereby improving the energy utilization efficiency of electronic devices, reducing heat generation and energy waste, and contributing to improved device stability and lifespan.
[0018] 3. Significantly Enhanced Temperature Stability: By controlling the composition and preparation process of the ceramic, particularly through appropriate doping and annealing treatments, this invention achieves a dielectric constant change rate of less than 3% over a wide temperature range of -70℃ to 180℃. For example, the temperature change rate in Example 3 is only 2.2%, while the comparative example is as high as 15%. This excellent temperature stability ensures that electronic devices maintain stable performance even in extreme temperature environments, avoiding capacitance fluctuations and performance degradation caused by temperature changes, thus broadening the application range and environmental adaptability of electronic devices.
[0019] 4. Improved resistivity of ceramic compositions: By doping with specific oxides and optimizing the preparation process, this invention effectively improves the resistivity of ceramic compositions. For example, the resistivity in Example 1 reaches 1×10⁻⁶. 12 Ω・m, significantly higher than the comparative example of 5×10 10 Ω・m. High resistivity helps reduce current leakage, enhances the ceramic composition's ability to impede current, and improves the electrical safety and stability of electronic devices.
[0020] 5. Improved Breakdown Strength: The ceramic composition prepared by this invention exhibits higher breakdown strength. The breakdown strength in Examples 1-3 is between 45-55 kV / mm, while the comparative example is only 30 kV / mm. Higher breakdown strength means that the ceramic can withstand higher electric field strengths without breaking down, enhancing the reliability and stability of electronic devices under high-voltage environments and ensuring the normal operation and safety of equipment.
[0021] 6. Optimizing the microstructure of ceramics: Innovative preparation processes, such as cryogenic ball milling, reduce particle agglomeration; microwave-assisted pre-firing promotes uniform component distribution; and multi-stage sintering and annealing eliminate internal stress and defects, resulting in a dense and uniform microstructure in the ceramics. This optimization of the microstructure reduces porosity and defects, further improving the physical and electrical properties of ceramics, such as strength, toughness, and conductivity.
[0022] 7. Innovative preparation process advantages: Cryogenic ball milling technology can refine particles, improve the reactivity and uniformity of raw materials, and reduce production difficulty; microwave-assisted pre-calcination accelerates the reaction process and improves efficiency; sintering and annealing processes control temperature and time, reducing energy consumption. These process improvements work together to reduce equipment requirements, improve production efficiency, and lower production costs, which is conducive to large-scale industrial production and application.
[0023] 8. Meeting the Needs of High-End Applications: The ceramic composition prepared by this invention possesses high dielectric constant, low loss, good temperature stability, and high electrical performance, meeting the stringent requirements for high-performance dielectric materials in fields such as high-frequency electronic devices, large-capacity capacitors, and microwave communications. This provides strong support for technological advancements and product performance improvements in these fields, and promotes the development of related industries. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the components of the composition in this invention; Figure 2 This is a schematic diagram of the doping components in this invention; Figure 3 This is a schematic flowchart of the preparation method of the composition in this invention. Detailed Implementation
[0025] With the rapid development of electronic technology, the demand for high-performance dielectric materials is becoming increasingly urgent. This invention relates to a high-temperature-stability, high-dielectric-constant ceramic composition and its preparation method, aiming to meet the stringent requirements for dielectric materials in fields such as high-frequency electronic devices, large-capacity capacitors, and microwave communications. The technical solution and effects of this invention will be described in detail below through specific embodiments, comparative examples, and experimental examples. The implementation methods of this invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are for illustrative purposes only and should not be used to limit the scope of this invention.
[0026] Example 1: Ceramic composition components: Main component: Barium titanate (BaTiO3) with high purity, uniform particle size and high dielectric constant is selected, and its content accounts for 65% of the total mass of the ceramic composition.
[0027] Doping components: Rare earth element oxides: lanthanum oxide (La2O3) 4%, neodymium oxide (Nd2O3) 3%.
[0028] Alkaline earth metal oxides: 5% magnesium oxide (MgO) and 3% calcium oxide (CaO).
[0029] Transition metal oxides: 2% copper oxide (CuO) and 2% manganese oxide (MnO2).
[0030] Functional additives: 16%.
[0031] Preparation method: Raw material pretreatment: Cryogenic ball milling: The ball milling jar is placed in a low temperature environment of -30℃, using zirconia balls with a diameter of 5mm, a ball-to-material ratio of 5:1, a milling time of 10 hours, and a rotation speed of 300 rpm.
[0032] Microwave-assisted preheating: preheating temperature is 600℃, time is 2 hours, microwave power is 800W.
[0033] Molding: The granulated powder is placed into a mold with a diameter of 10mm and dry-pressed under a pressure of 200MPa to obtain a cylindrical blank.
[0034] Debinding and pre-firing: The formed green body is placed in a box-type resistance furnace and heated to 450°C at a heating rate of 2°C / min for debinding. Then, it is heated to 800°C at a heating rate of 3°C / min for pre-firing and held at that temperature for 3 hours to form a ceramic precursor.
[0035] Sintering: The pre-fired ceramic precursor is placed in a high-temperature tube furnace and heated to 1300°C at a heating rate of 8°C / min under an atmosphere of nitrogen to oxygen volume ratio of 3:1. The temperature is held for 3 hours to allow the ceramic to be fully sintered and form a dense ceramic body.
[0036] Annealing treatment: After sintering, the ceramic body is quickly transferred to another box-type resistance furnace for annealing at 600°C and held at that temperature for 1.5 hours, and then cooled to room temperature with the furnace.
[0037] Surface treatment and electrode fabrication: Pulse annealing with a pulse width of 50 μs and a frequency of 20 kHz was used. Silver electrodes with a thickness of 2 μm were fabricated on the upper and lower surfaces of the ceramic body using vacuum evaporation.
[0038] Example 2: Ceramic composition components: Main component: Barium titanate (BaTiO3) with high purity, uniform particle size and high dielectric constant is selected, and its content accounts for 60% of the total mass of the ceramic composition.
[0039] Doping components: Rare earth element oxides: lanthanum oxide (La2O3) 5%, neodymium oxide (Nd2O3) 2%.
[0040] Alkaline earth metal oxides: 6% magnesium oxide (MgO) and 2% calcium oxide (CaO).
[0041] Transition metal oxides: 3% copper oxide (CuO) and 2% manganese oxide (MnO2).
[0042] Functional additives: 20%.
[0043] Preparation method: Raw material pretreatment: Cryogenic ball milling: The ball milling jar is placed in a low temperature environment of -20℃, using zirconia balls with a diameter of 3mm, a ball-to-material ratio of 4:1, a milling time of 8 hours, and a rotation speed of 250 rpm.
[0044] Microwave-assisted preheating: the preheating temperature is 550℃, the time is 1.5 hours, and the microwave power is 700W.
[0045] Molding: The granulated powder is placed into a square mold with a side length of 8mm and dry-pressed under a pressure of 180MPa to obtain a square blank.
[0046] Debinding and pre-firing: The formed green body is placed in a box-type resistance furnace and heated to 400℃ at a heating rate of 1.5℃ / min for debinding. Then, it is heated to 750℃ at a heating rate of 2.5℃ / min for pre-firing and held at that temperature for 2.5 hours to form a ceramic precursor.
[0047] Sintering: The pre-fired ceramic precursor is placed in a high-temperature tube furnace and heated to 1250°C at a heating rate of 7°C / min under an atmosphere of nitrogen to oxygen volume ratio of 3:1. The temperature is held for 2.5 hours to allow the ceramic to be fully sintered and form a dense ceramic body.
[0048] Annealing treatment: After sintering, the ceramic body is quickly transferred to another box-type resistance furnace for annealing at 550°C and held at that temperature for 1 hour, and then cooled to room temperature with the furnace.
[0049] Surface treatment and electrode fabrication: Pulse annealing with a pulse width of 40 μs and a frequency of 15 kHz was used. Silver electrodes with a thickness of 1.5 μm were fabricated on the upper and lower surfaces of the ceramic body using vacuum evaporation.
[0050] Example 3: Ceramic composition components: Main component: Barium titanate (BaTiO3) with high purity, uniform particle size and high dielectric constant is selected, and its content accounts for 70% of the total mass of the ceramic composition.
[0051] Doping components: Rare earth element oxides: lanthanum oxide (La2O3) 3%, neodymium oxide (Nd2O3) 4%.
[0052] Alkaline earth metal oxides: 4% magnesium oxide (MgO) and 4% calcium oxide (CaO).
[0053] Transition metal oxides: copper oxide (CuO) 2.5%, manganese oxide (MnO2) 2.5%.
[0054] Functional additives: 10%.
[0055] Preparation method: Raw material pretreatment: Cryogenic ball milling: The ball milling jar is placed in a low-temperature environment of -40℃, using zirconia balls with a diameter of 4mm, a ball-to-material ratio of 4.5:1, a milling time of 9 hours, and a rotation speed of 280 rpm.
[0056] Microwave-assisted preheating: the preheating temperature is 580℃, the time is 1.8 hours, and the microwave power is 750W.
[0057] Molding: The granulated powder is placed into a mold with a diameter of 12mm and dry-pressed under a pressure of 220MPa to obtain a cylindrical blank.
[0058] Debinding and pre-firing: The formed green body is placed in a box-type resistance furnace and heated to 430°C at a heating rate of 1.8°C / min for debinding. Then, it is heated to 850°C at a heating rate of 2.8°C / min for pre-firing and held at that temperature for 2.8 hours to form a ceramic precursor.
[0059] Sintering: The pre-fired ceramic precursor is placed in a high-temperature tube furnace and heated to 1350°C at a heating rate of 9°C / min under an atmosphere of nitrogen to oxygen volume ratio of 3:1. The temperature is held for 3.5 hours to allow the ceramic to be fully sintered and form a dense ceramic body.
[0060] Annealing treatment: After sintering, the ceramic body is quickly transferred to another box-type resistance furnace for annealing at 650°C and held for 2 hours, and then cooled to room temperature with the furnace.
[0061] Surface treatment and electrode fabrication: Pulse annealing was used with a pulse width of 60 μs and a frequency of 25 kHz. Silver electrodes with a thickness of 2.5 μm were fabricated on the upper and lower surfaces of the ceramic body using vacuum evaporation.
[0062] Example 4: Ceramic composition components: Main component: Barium titanate (BaTiO3) 70% Doping components: Rare earth element oxides: Lanthanum oxide (La₂O₃) 3%, Neodymium oxide (Nd₂O₃) 4%; Alkaline earth metal oxides: Magnesium oxide (MgO) 4%, Calcium oxide (CaO) 4%; Transition metal oxides: 2.5% copper oxide (CuO) and 2.5% manganese oxide (MnO2).
[0063] Functional additives: 10% (consistent with Example 3).
[0064] Preparation method: SPS sintering; Equipment: SPS-515S type spark plasma sintering furnace; Sintering parameters: Temperature: 1200℃ (150℃ lower than the original Example 3); Pressure: 50 MPa; Heating rate: 100℃ / min (rapid heating); Insulation time: 5 minutes (extremely short insulation time); Current waveform: DC pulse (60% duty cycle).
[0065] Other steps The raw material pretreatment, molding, debinding, annealing, and electrode preparation are completely consistent with those in Example 3.
[0066] Example 5: Ceramic composition components: Main component: Barium titanate (BaTiO3) 65%.
[0067] Doping components: Rare earth element oxides: Lanthanum oxide (La₂O₃) 4%, Neodymium oxide (Nd₂O₃) 3%; Alkaline earth metal oxides: 5% magnesium oxide (MgO), 3% calcium oxide (CaO); Transition metal oxides: 2% copper oxide (CuO) and 2% manganese oxide (MnO2).
[0068] Functional additives: 16% (consistent with Example 1).
[0069] Preparation method: HIP sintering; Equipment: AIP-250 hot isostatic press; Sintering parameters: Temperature: 1350℃ (consistent with Example 3); Pressure: 100MPa (ultra-high pressure); Heating rate: 10℃ / min; Incubation time: 2 hours; Protective atmosphere: Argon.
[0070] Other steps: The raw material pretreatment, molding, debinding, annealing, and electrode preparation are completely consistent with those in Example 1.
[0071] Performance Comparison Table:
[0072] It can be seen that the spark plasma sintering (SPS) of Example 4 has the following characteristics: Rapid densification: Pulsed current promotes the formation of necking between particles, achieving 99.5% density within 5 minutes (traditional sintering requires 3 hours).
[0073] Grain refinement: Extremely short holding time inhibits grain growth, reducing the average grain size from 1.2μm to 0.8μm, increasing the grain boundary area by 30%, and reducing dielectric loss by 28%.
[0074] Energy-saving and efficient: The sintering temperature is 150°C lower than that of traditional methods, reducing energy consumption by 40%, making it suitable for large-scale production.
[0075] Example 5's hot isostatic pressing (HIP) has the following characteristics: Ultra-high pressure densification: 100MPa pressure eliminates closed pores, density exceeds 99.8%, and breakdown strength is increased by 27%.
[0076] Isotropic enhancement: The uniform pressure field eliminates internal stress, increases resistivity by 50%, and improves temperature stability by 31%.
[0077] Structural uniformity: Under high temperature and high pressure, element diffusion is more complete, doping distribution uniformity is improved by 40%, and dielectric constant consistency is significantly enhanced.
[0078] Comparative example: The preparation method and composition are conventional. The main component is barium titanate (BaTiO3), with a content of 80%, and the only dopant is magnesium oxide (MgO), with a content of 20%. The preparation process uses ordinary ball milling without microwave-assisted pre-firing. The binder removal temperature is 350℃, the pre-firing temperature is 650℃, and the sintering temperature is 1100℃. There is no annealing treatment. The electrode is prepared by screen printing silver paste.
[0079] To visually demonstrate the superior performance of the high-performance, high-dielectric-constant ceramic composition of the present invention, performance tests were conducted on the above-mentioned embodiments and comparative examples. The test results are summarized in the table below:
[0080] As can be seen from the above data, the embodiments of the present invention are significantly superior to the comparative examples in terms of dielectric constant, dielectric loss, temperature stability, resistivity, and breakdown strength.
[0081] Performance Breakthrough: High dielectric constant: Example 3 (barium titanate 70%): dielectric constant 3605, an 80% improvement over the comparative example (2000).
[0082] Example 5 (HIP sintering): Dielectric constant 4586, 25% higher than conventional sintering (3600), due to grain refinement and defect reduction under ultra-high pressure.
[0083] Low dielectric loss: Example 4 (SPS sintering): The loss was 0.005, which is 28% lower than that of conventional sintering (0.007), thanks to the suppression of grain boundary defects by pulsed current.
[0084] Wide temperature range stability: Example 5: The dielectric constant change rate from -70℃ to 180℃ is 1.53%, which is 90% higher than the comparative example (15%), achieved by stabilizing the crystal structure through doping elements.
[0085] Performance improvements resulting from innovative manufacturing processes: SPS sintering technology (Example 4): Rapid densification: Density reaches 99.5% within 5 minutes (traditional sintering requires 3 hours), and pulsed current promotes particle necking.
[0086] Grain refinement: The average grain size decreased from 1.2 μm to 0.8 μm, the grain boundary area increased by 30%, and the breakdown strength increased by 18% (65 kV / mm vs 55 kV / mm).
[0087] Energy-saving and efficient: The sintering temperature is reduced by 150℃, and energy consumption is reduced by 40%, making it suitable for industrial production.
[0088] HIP sintering technology (Example 5): Ultra-high voltage densification: 100MPa pressure eliminates closed pores, density exceeds 99.8%, and breakdown strength is increased by 27% (70kV / mm vs 55kV / mm).
[0089] Isotropic enhancement: A uniform pressure field eliminates internal stress, increasing resistivity by 50% (1.8 × 10⁻⁶). 12 Ω・mvs1.2×10 12 Ω・m).
[0090] The comprehensive advantages brought by collaborative optimization: Resistivity and breakdown strength: Example 5: Resistivity 1.8 × 10⁻⁶ 12 Ω・m, breakdown strength 70kV / mm, compared with comparative example (5×10 10 Significant improvements in Ω・m and 30kV / mm (to meet the requirements of high-voltage devices).
[0091] Process compatibility: Examples 1-3: Balancing sintering difficulty and performance by adjusting the proportion of functional additives (10%-20%). For example, Example 3 (10% additive) achieves optimal overall performance at a low content.
[0092] Environmental adaptability: Example 4: Temperature change rate of 1.8%, suitable for electronic devices in extreme environments, such as aerospace and deep-sea exploration.
[0093] Practical application value: Miniaturized electronic devices: The high dielectric constant (4586) allows for a 60% reduction in capacitor volume, meeting the compact requirements of fields such as 5G base stations and electric vehicles.
[0094] High-frequency stability: Low loss (0.005) reduces signal attenuation, making it suitable for high-frequency scenarios such as microwave communication and radar systems.
[0095] Improved reliability: Wide temperature range stability (±1.5%) and high breakdown strength (70kV / mm) extend equipment life and reduce maintenance costs.
[0096] This invention achieves three core breakthroughs in ceramic materials through synergistic optimization of composition and process: high dielectric constant (4586), low loss (0.005), and wide temperature range stability (±1.5%). Combined with the efficient fabrication using SPS / HIP sintering technology, it provides a groundbreaking solution for high-frequency electronic devices, high-voltage capacitors, and other fields. The systematic verification in Examples 1-5 fully demonstrates the technical advantages and engineering practicality of the invention.
[0097] The proportion of functional additives needs to be dynamically adjusted according to the target performance (such as high dielectric constant or low loss), and combined with process optimization, in order to maximize the material performance.
[0098] In summary, regarding the composition design of ceramic compositions, using high-purity, uniformly sized barium titanate with high dielectric constant as the main component, combined with various dopants such as rare earth oxides, alkaline earth metal oxides, and transition metal oxides, fundamentally improves the crystal structure and electrical properties of the ceramic. This optimized composition not only increases the dielectric constant but also enhances the ceramic's temperature stability, resistivity, and breakdown strength, while reducing dielectric loss, laying the foundation for the realization of high-performance ceramics.
[0099] In terms of preparation methods, a series of advanced technologies and precise control steps were introduced. Cryogenic ball milling effectively refined the particles, reduced agglomeration, and improved the reactivity and compositional uniformity of the raw materials. Microwave-assisted pre-firing made the pre-firing process more uniform and rapid, facilitating the removal of volatile components and promoting solid-phase reactions between raw materials. Precisely controlled steps such as debinding and pre-firing, multi-stage sintering, and annealing further optimized the ceramic's microstructure, eliminated internal stress, and made the ceramic more dense and uniform. Surface treatment and electrode preparation ensured a good bond between the ceramic and the electrode, improving the overall electrical performance.
[0100] The detailed data and performance of Examples 1-5 clearly demonstrate the stable performance and excellent effects of this invention under different component ratios and process parameters. Compared with the conventional methods of comparative examples, this invention achieves significant improvements in key performance indicators such as dielectric constant, dielectric loss, temperature stability, resistivity, and breakdown strength. This not only proves the feasibility and effectiveness of the technical solution of this invention but also demonstrates its great potential in practical applications.
[0101] This invention provides a high-performance, high-reliability dielectric material solution for fields such as high-frequency electronic devices, large-capacity capacitors, and microwave communications. Its innovative composition design and preparation process not only meet the urgent needs of current electronic technology for high-performance dielectric materials but also provide strong support for technological development and product upgrades in related fields. With the continuous advancement of electronic technology and the sustained growth of market demand, this invention is expected to occupy an important position in the future electronic materials market, driving the development and progress of the entire industry.
[0102] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.
Claims
1. A high-temperature-stability, high-dielectric-constant ceramic composition, characterized in that, It includes a main component and a dopant component, wherein the main component is barium titanate with high purity, uniform particle size and high dielectric constant, and its content accounts for 60%-70% of the total mass of the ceramic composition; The doping components include 5%-8% rare earth element oxides, 5%-8% alkaline earth metal oxides and 3%-5% transition metal oxides by mass. The total of all ingredients is 100%, with the remainder being functional additives.
2. The high-temperature-stability, high-dielectric-constant ceramic composition according to claim 1, characterized in that, The rare earth element oxides are lanthanum oxide and neodymium oxide, the alkaline earth metal oxides are magnesium oxide and calcium oxide, and the transition metal oxides are copper oxide and manganese oxide.
3. A method for preparing a high-temperature-stability, high-dielectric-constant ceramic composition as described in claim 1 or 2, characterized in that, Includes the following steps: S1: Raw material pretreatment: The particles are refined by cryogenic ball milling technology, and microwave-assisted heating technology is introduced in the pre-calcination stage to control the temperature, time and power of pre-calcination in order to remove volatile components; S2: Molding: The granulated powder is placed into a mold of a specific size and dry-pressed under pressure to obtain a blank of a specific shape and size; S3: Debinding and Pre-firing: The formed green body is placed in a box-type resistance furnace and heated to a specific temperature at a slow heating rate to debind the material. The temperature is then increased to perform pre-firing, so that the raw materials undergo a preliminary solid-phase reaction to form a ceramic precursor. S4: Sintering: The pre-fired ceramic precursor is placed in a high-temperature tube furnace and heated to a high temperature at an appropriate heating rate under a specific atmosphere and held for a certain time to allow the ceramic to be fully sintered and form a dense ceramic body. S5: Annealing treatment: After sintering, the ceramic body is quickly transferred to another box-type resistance furnace, annealed at a specific temperature and held for a certain time, and then cooled to room temperature with the furnace. S6: Surface treatment and electrode preparation: Pulse annealing and vacuum evaporation are used to prepare silver electrodes of a specific thickness on the upper and lower surfaces of the ceramic body.
4. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, In the aforementioned cryogenic ball milling technology, the milling jar is placed in a low-temperature environment of -50°C to -20°C.
5. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, The heating rate of the glue removal process is 1-3℃ / min, and the glue removal temperature is 400-500℃.
6. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, The pre-firing temperature is 700-900℃, and the pre-firing time is 2-4 hours.
7. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, The sintering process involves a heating rate of 5-10℃ / min, a sintering temperature of 1200-1400℃, a holding time of 2-4 hours, and a sintering atmosphere of a mixture of nitrogen and oxygen with a volume ratio of 3:
1.
8. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, The annealing process is carried out at a temperature of 500-700℃ for 1-2 hours.
9. The method for preparing the high-temperature-stability, high-dielectric-constant ceramic composition according to claim 3, characterized in that, The thickness of the silver electrode prepared by vacuum evaporation is 1-3 micrometers.
10. A method for preparing a high-temperature-stability, high-dielectric-constant ceramic composition according to any one of claims 3-9, characterized in that, The ceramic composition prepared by the method exhibits a dielectric constant change rate of ±3% within a temperature range of -70℃ to 180℃.