High dielectric constant and low dielectric loss st-based ceramic and method of making same

Abstract

The application discloses a high-dielectric-constant and low-dielectric-loss ST-based ceramic and a preparation method thereof. x The value range is 0-0.015. The preparation process comprises the following core steps in sequence: primary ball milling, drying, pressing into blocks, crushing, secondary ball milling, sieving, cold isostatic pressing forming, and nitrogen atmosphere sintering. The ceramic material prepared through the process realizes a key breakthrough in dielectric performance: the relative dielectric constant is as high as 1.5*10 4 The above shows significant giant dielectric characteristics; the dielectric loss is as low as below 0.08, energy loss control is excellent; and the dielectric performance is stable in a wide frequency range, effectively solving the pain point of poor frequency adaptability of traditional high-dielectric materials. The process is simple and controllable, the cost is controllable, and is suitable for large-scale industrial production, thereby providing core material support for the miniaturization and high-frequency development of high-end electronic components, and having a very wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of high-energy-storage dielectric ceramic capacitors, specifically to SrTi 1-0.5x Mn x Preparation method of O3 ceramic materials with large dielectric constant, low dielectric loss and frequency stability. Background Technology

[0002] Dielectric constant greater than 10 4 Materials with high dielectric constants are defined as materials with giant dielectric constants. These materials are the core foundation supporting the miniaturization and high precision of electronic devices, and their performance directly determines the integration density and reliability of the devices. Therefore, developing dielectric materials that combine giant dielectric properties, low dielectric loss, and excellent frequency stability has become a key research direction in the field of electronic materials. Currently reported high dielectric materials (such as BaTiO3, CaCu3Ti4O3, etc.) 12 While materials such as NiO and TiO2 can achieve certain high dielectric properties, they generally have significant drawbacks: high dielectric loss leads to serious energy waste, and poor frequency stability results in drastic fluctuations in dielectric properties over a wide frequency range, making it difficult to meet the requirements of high-end electronic devices.

[0003] Among numerous candidate systems, SrTiO3 (ST)-based materials are widely recognized as ideal carriers for achieving high-performance giant dielectric properties due to their superior dielectric response stability over a wide temperature and frequency range. However, existing technologies face a core bottleneck: increasing the dielectric constant of ST-based ceramics to 10... 4 When the dielectric strength reaches the level of giant dielectric (i.e., the standard of giant dielectric is reached), it is often accompanied by a significant deterioration in frequency stability and a further increase in dielectric loss. These three factors are difficult to balance and seriously limit its promotion and application in practical scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a method for obtaining ultra-high giant dielectric constant (γ) under sintering conditions in a non-hydrogen environment. r >1.5×10 4 ) and low dielectric loss (tan δ Ceramic materials with a molecular weight of < 0.08 have a simple preparation process, low material cost, safe process, and are environmentally friendly.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A high dielectric constant, low dielectric loss, and excellent frequency stability ST-based ceramic material is characterized by the following stoichiometric formula: SrTi 1-0.5x Mn x O3, x =0, 0.005, 0.010, 0.015. The dielectric constant of this material is higher than 10. 4(Meets the giant dielectric standard), dielectric loss is less than 0.08, and dielectric performance remains stable over a wide frequency range, achieving a synergistic balance of the three core performance characteristics.

[0006] Furthermore, the preparation method of the aforementioned ST-based ceramic material with giant dielectric, low loss, and excellent frequency stability includes the following steps: Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 ( x =0, 0.005, 0.010, 0.015 (representing the molar doping amount of Mn), weigh out the corresponding masses of SrCO3, TiO2 and MnO2, mix, ball mill and dry to obtain a uniform initial mixture A, which lays the foundation for the realization of the material's giant dielectric properties, low loss and frequency stability.

[0007] Step 2: After grinding and pressing mixture A into blocks, calcinate them in air at 1000-1200 °C for 2 to 4 hours. The resulting calcined blocks are then crushed, wet-milled, dried, and sieved through a 120-mesh sieve to obtain SrTi. 1-0.5x Mn x The powder with O3 as the main crystalline phase is reserved for later use. By precisely controlling the calcination temperature and time and optimizing the ball milling process, the purity and dispersion uniformity of the powder crystalline phase are ensured, providing structural support for the stability of dielectric properties.

[0008] Step 3: The main crystalline phase powder obtained after sieving is pressed into a blank, and after cold isostatic pressing for densification, it is placed in an alumina sagger lined with a zirconia pad, and then transferred into a tube furnace for final sintering at 1470-1520℃ in a nitrogen atmosphere. Nitrogen atmosphere sintering can avoid performance fluctuations caused by reducing atmosphere, and the precisely controlled sintering temperature range can optimize the microstructure of the material, helping to achieve the synergistic effect of huge dielectric, low loss and frequency stability.

[0009] The complete batching for ball milling in step 1: Zirconia grinding balls, deionized water and materials are mixed at a mass ratio of 1:5:(0.8~1.2) and then ball milled. The resulting slurry is dried at 75~100℃ for 16~24 hours.

[0010] The complete batching for ball milling in step 2 is as follows: zirconium oxide grinding balls, deionized water and powder are mixed at a mass ratio of 1:(4.5~5):(0.8~1.2). The slurry after ball milling is dried at 75-100℃ for 16-24 hours.

[0011] The pressing process in step 3 involves hand-pressing the blank using a mold followed by cold isostatic pressing. The pressure is maintained at 200-220 MPa for 4 minutes, then at 190 MPa for another 4 minutes, and finally released at a rate of 40 MPa / min.

[0012] Furthermore, after polishing and cleaning the sintered ceramic sample, silver paste was applied to its surface and sintered to form an electrode, ultimately producing SrTi with high dielectric properties. 1-0.5x Mn x O3-based ceramic materials.

[0013] Furthermore, the SrTi 1-0.5x Mn x The sintering conditions for the O3 ceramic-based ceramic material with a large dielectric constant and low dielectric loss coated with a silver electrode were set as follows: holding at a temperature of 650-750 ℃ ​​for 20-30 minutes.

[0014] And, SrTi prepared by the above method 1-0.5x Mn x O3 ceramic-based ceramic materials with high dielectric constant and low dielectric loss.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: SrTi prepared in this invention 1-0.5x Mn x O3-based ceramic materials achieve a synergistic balance of giant dielectric constant, low loss, and excellent frequency stability: dielectric constant is higher than 10. 4 It meets the core standards of giant dielectric materials, with outstanding charge storage capacity; dielectric loss is less than 0.08, energy loss is precisely controlled, and operating efficiency is excellent; moreover, it maintains stable dielectric performance over a wide frequency range, effectively avoiding the pain point of poor frequency adaptability of traditional high dielectric materials, and fully meeting the stringent requirements of high-end applications for performance consistency.

[0016] The material's preparation process is simple and controllable, with low raw material costs. Furthermore, the entire process utilizes a nitrogen atmosphere for sintering, completely avoiding the safety risks associated with reducing atmospheres and aligning with green and environmentally friendly production principles. While possessing three core dielectric advantages, it also boasts significant cost advantages, demonstrating strong technical adaptability and market competitiveness in high-end electronic components and other industrial sectors, indicating a very broad application prospect. Attached Figure Description

[0017] Figure 1 It is SrTi in Examples 1-4 1-0.5x Mn x XRD patterns of O3 ceramic materials; Figure 2 SrTi in Examples 2-41-0.5x Mn x SEM images of O3 ceramic materials; Figure 3 It is SrTi in Examples 1-4 1-0.5x Mn x Dielectric spectrum of O3 ceramic materials; Detailed Implementation

[0018] The embodiments of the present invention will be described in further detail below: A high dielectric constant and low dielectric loss ST-based ceramic material: SrTi 1-0.5x Mn x O3, x =0, 0.005, 0.010, 0.015, x It represents the percentage of molar mass.

[0019] The preparation method of the above-mentioned ST-based ceramic material with giant dielectric constant and low dielectric loss includes the following steps: Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 (of which) x =0, 0.005, 0.010, 0.015 (representing the molar doping ratio of manganese), accurately weigh SrCO3, TiO2, and MnO2 raw materials. After mixing, ball mill them according to the mass ratio of the mixed raw materials, zirconia balls, and deionized water of 1:5:(0.8~1.2). The slurry obtained from ball milling is dried at 75~100 ℃ for 16~24 hours to finally obtain a homogeneous mixture A.

[0020] Step 2: After grinding and briquetting, mixture A is calcined in air at 1000-1200℃ for 2-4 hours. The calcined product is then pulverized and wet-milled at a mass ratio of 1:(4.5-5):(0.8-1.2) of calcined product to zirconia spheroids and deionized water. The milled slurry is dried at 75-100℃ for 16-24 hours, then ground and passed through a 120-mesh sieve to finally obtain SrTi. 1-0.5x Mn x O3 as the main crystalline phase powder is used as a backup raw material.

[0021] Step 3: The sieved powder is formed into a green body using a cold isostatic pressing process. The specific pressure procedure is as follows: first, maintain a pressure of 200-220 MPa for 4 minutes, then adjust to 190 MPa and continue holding the pressure for 4 minutes, and finally release the pressure at a rate of 40 MPa / min. The formed green body is placed in an alumina sagger lined with a zirconia pad and transferred to a tube furnace for sintering at 1370-1520℃ under a nitrogen atmosphere.

[0022] Furthermore, the sintered ceramic sample was polished and cleaned, then coated with silver electrode paste, and sintered at 650-750 °C for 20-30 minutes to finally obtain SrTi. 1-0.5x Mn x O3 ( x = 0, 0.005, 0.010, 0.015) based ceramic materials.

[0023] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the following specific embodiments are merely further elaborations on the present invention and not further limitations thereof: Example 1

[0024] Chemical formula SrTi 1-0.5x Mn x O3, in which x =0.

[0025] Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 (of which) x =0, x (The molar mass percentage) SrCO3, TiO2 and MnO2 raw materials were weighed out according to their respective masses, and after thorough mixing, ball milling and drying, a homogeneous mixture A was obtained.

[0026] Step 2: Grind and press mixture A into blocks, then place it in air and calcine it at 1000-1200 ℃ for 2 to 4 hours. The calcined product is then crushed, ball-milled, dried, and ground again, and sieved through a 120-mesh sieve to finally obtain a spare powder with ST as the main crystalline phase.

[0027] Step 3: The sieved powder is pressed into a green body using a cold isostatic pressing process. The specific pressure program is as follows: first, maintain a pressure of 200-220 MPa for 4 minutes, then continue to maintain a pressure of 190 MPa for 4 minutes, and finally release the pressure at a rate of 40 MPa / min.

[0028] Further, the pressed blank is placed in an alumina sagger equipped with a zirconia pad, and then the sagger is moved into a tube furnace, where the sintering process is completed in a nitrogen protective atmosphere at a temperature range of 1370-1520 °C.

[0029] Furthermore, the sintered ceramic samples are successively polished and cleaned, then coated with silver electrode paste, and heat-treated at 650-750 ℃ ​​for 20-30 minutes to finally obtain the desired ST ceramic. Example 2

[0030] Chemical formula SrTi 1-0.5x Mn x O3, in which x =0.005.

[0031] Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 (of which) x =0, x (The molar mass percentage) SrCO3, TiO2 and MnO2 raw materials were weighed out according to their respective masses, and after thorough mixing, ball milling and drying, a homogeneous mixture A was obtained.

[0032] Step 2: Grind and press mixture A into blocks, then place them in air and calcine them at 1000-1200 °C for 2 to 4 hours. The calcined product is then pulverized, ball-milled, dried, and ground again before being sieved through a 120-mesh sieve to finally obtain SrTi. 0.9975 Mn 0.005 O3 as the main crystalline phase is used as a backup powder.

[0033] Step 3: The sieved powder is pressed into a green body using a cold isostatic pressing process. The specific pressure program is as follows: first, maintain a pressure of 200-220 MPa for 4 minutes, then continue to maintain a pressure of 190 MPa for 4 minutes, and finally release the pressure at a rate of 40 MPa / min.

[0034] Further, the pressed blank is placed in an alumina sagger equipped with a zirconia pad, and then the sagger is moved into a tube furnace, where the sintering process is completed in a nitrogen protective atmosphere at a temperature range of 1370-1520 °C.

[0035] Furthermore, the sintered ceramic samples were successively polished and cleaned, then coated with silver electrode paste, and heat-treated at 650-750 °C for 20-30 minutes to finally obtain the desired SrTi. 0.9975 Mn 0.005 O3 ceramics. Example 3

[0036] Chemical formula SrTi 1-0.5x Mn x O3, in which x =0.010.

[0037] Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 (of which) x =0, x(The molar mass percentage) SrCO3, TiO2 and MnO2 raw materials were weighed out according to their respective masses, and after thorough mixing, ball milling and drying, a homogeneous mixture A was obtained.

[0038] Step 2: Grind and press mixture A into blocks, then place them in air and calcine them at 1000-1200 °C for 2 to 4 hours. The calcined product is then pulverized, ball-milled, dried, and ground again before being sieved through a 120-mesh sieve to finally obtain SrTi. 0.9975 Mn 0.01 O3 as the main crystalline phase is used as a backup powder.

[0039] Step 3: The sieved powder is pressed into a green body using a cold isostatic pressing process. The specific pressure program is as follows: first, maintain a pressure of 200-220 MPa for 4 minutes, then continue to maintain a pressure of 190 MPa for 4 minutes, and finally release the pressure at a rate of 40 MPa / min.

[0040] Further, the pressed blank is placed in an alumina sagger equipped with a zirconia pad, and then the sagger is moved into a tube furnace, where the sintering process is completed in a nitrogen protective atmosphere at a temperature range of 1370-1520 °C.

[0041] Furthermore, the sintered ceramic samples were successively polished and cleaned, then coated with silver electrode paste, and heat-treated at 650-750 °C for 20-30 minutes to finally obtain the desired SrTi. 0.9975 Mn 0.01 O3 ceramics. Example 4

[0042] Chemical formula SrTi 1-0.5x Mn x O3, in which x =0.015.

[0043] Step 1: Based on the stoichiometric formula SrTi 1-0.5x Mn x O3 (of which) x =0, x (The molar mass percentage) SrCO3, TiO2 and MnO2 raw materials were weighed out according to their respective masses, and after thorough mixing, ball milling and drying, a homogeneous mixture A was obtained.

[0044] Step 2: Grind and press mixture A into blocks, then place them in air and calcine them at 1000-1200 °C for 2 to 4 hours. The calcined product is then pulverized, ball-milled, dried, and ground again before being sieved through a 120-mesh sieve to finally obtain SrTi. 0.9975 Mn0.015 O3 as the main crystalline phase is used as a backup powder.

[0045] Step 3: The sieved powder is pressed into a green body using a cold isostatic pressing process. The specific pressure program is as follows: first, maintain a pressure of 200-220 MPa for 4 minutes, then continue to maintain a pressure of 190 MPa for 4 minutes, and finally release the pressure at a rate of 40 MPa / min.

[0046] Further, the pressed blank is placed in an alumina sagger equipped with a zirconia pad, and then the sagger is moved into a tube furnace, where the sintering process is completed in a nitrogen protective atmosphere at a temperature range of 1370-1520 °C.

[0047] Furthermore, the sintered ceramic samples were successively polished and cleaned, then coated with silver electrode paste, and heat-treated at 650-750 °C for 20-30 minutes to finally obtain the desired SrTi. 0.9975 Mn 0.015 O3 ceramics. Example 5

[0048] XRD tests were performed on the samples prepared in Examples 1-4 to obtain... Figure 1 (SrTi) 1-0.5x Mn x XRD pattern of O3 ceramic material). From Figure 1 As can be seen, all samples exhibit a pure cubic perovskite crystal structure, matching the standard card (PDF#35-0734). They possess a single, stable crystal phase structure without any second-phase impurities, laying a solid structural foundation for the material to achieve synergistic performance of giant dielectric, low loss, and frequency stability.

[0049] SEM images of the samples from Examples 2-4 were taken to obtain... Figure 2 (SrTi) 1-0.5x Mn x SEM image of O3 ceramics. From Figure 2 It can be observed that as the amount of MnO2 added increases, the grain size gradually becomes finer, and the small grains (MnO2) mainly gather in the grain region. This uniform micro-distribution can effectively suppress the increase of dielectric loss and enhance the performance stability of the material over a wide frequency range.

[0050] Dielectric properties were tested on samples from Examples 1-4, and the results were obtained. Figure 3 (SrTi) 1-0.5x Mn x (Dielectric spectrum of O3 ceramic materials). From... Figure 3The core advantages of the material can be clearly identified: (1) Outstanding giant dielectric properties: In the wide frequency range of 20Hz~1MHz, the dielectric constant of SMT10 and SMT15 samples remains at 10. 4 The above is true; among them, the SMT10 sample performed particularly well, with a dielectric constant consistently above 1.5 × 10⁻⁶ across the entire test frequency band. 4 (2) Excellent dielectric loss control: The dielectric loss of all sample examples is less than 0.08 in the frequency range of 20Hz to 1MHz, and the energy loss level is in the industry's excellent range. (3) Excellent frequency stability: Both dielectric constant and dielectric loss maintain stable fluctuations in a wide frequency range - especially the SMT10 sample, in the frequency range of 20Hz to 1MHz, the change rate of dielectric constant is <10%, which fully verifies the performance consistency of the material at different operating frequencies.

Claims

1. A high dielectric constant and low dielectric loss ST-based ceramic, characterized in that, The stoichiometric formula is: SrTi 1- 0.5x Mn x O3, x =0, 0.005, 0.010, 0.

015.

2. A method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material, characterized in that, Includes the following steps: Step 1: Using the chemical formula SrTi 1-0.5x Mn x O3 ( x Based on the ratios 0, 0.005, 0.010, and 0.015 (representing the molar ratio of Mn), accurately weigh the corresponding masses of SrCO3, TiO2, and MnO2 raw materials, and after mixing, ball milling, and drying, obtain a homogeneous mixture A. Step 2: After grinding and pressing mixture A into blocks, calcine it in air at 1000-1200 °C for 2 to 4 hours. The calcined product is then pulverized, ball-milled a second time, and sieved through a 120-mesh sieve to obtain SrTi. 1-0.5x Mn x Uniform powder of O3 main crystalline phase, for use in subsequent steps; Step 3: The sieved main crystalline phase powder is molded into a blank and subjected to cold isostatic pressing to improve density. Subsequently, the molded sample is placed in an alumina sagger lined with a zirconia pad and transferred together into a tube furnace for high-temperature sintering at 1470-1520 °C under a nitrogen atmosphere.

3. The method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 2, wherein the ball milling process in step 1 is specifically as follows: the mixture A, zirconia grinding balls and deionized water are mixed in a mass ratio of 1:5:(0.8~1.2) and then ball milled, and the resulting slurry is then dried at 75~100 ℃ for 16~24 hours.

4. The method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 2, wherein the ball milling process in step 2 is carried out according to the following ratio: zirconia grinding balls, deionized water and materials are mixed and ball milled at a mass ratio of 1:(4.5~5):(0.8~1.2), and the resulting slurry is dried at 75~100℃ for 16~24 hours.

5. The method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 2, wherein the pressing process in step 3 is as follows: after the powder is initially pressed into shape by a mold, it is then subjected to cold isostatic pressing under a pressure of 180-220 MPa to obtain a dense final blank.

6. The method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 2, wherein the sintering in step 3 is carried out in a box furnace, and the specific temperature regime is as follows: first, the temperature is raised to 1470-1520℃ in 290-314 minutes, and then held for 3 hours; then the temperature is lowered to 500℃ in 190-214 minutes, and finally the power is turned off and the furnace is cooled to room temperature.

7. The method for preparing a high dielectric constant and low dielectric loss SrTi-based ceramic material according to claim 1, wherein the obtained ceramic sample needs to be polished and cleaned, coated with silver electrode paste on its surface, and sintered to form the electrode, ultimately obtaining SrTi suitable for performance testing. 1-0.5x Mn x O3-based ceramic materials.

8. The method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 7, characterized in that, SrTi 1-0.5x Mn x The sintering conditions for silver electrodes in the preparation of O3 ceramic materials with large dielectric constant and low dielectric loss are: holding at 650-750℃ for 20-30 minutes.

9. A method for preparing a high dielectric constant and low dielectric loss ST-based ceramic material according to claim 7 or 8, characterized in that, SrTi 1-0.5x Mn x O3 ceramics are ceramic materials with high dielectric constant and low dielectric loss.

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