A ceramic material with wide temperature stability, low loss and high dielectric and a preparation method thereof

Abstract

This invention discloses a wide-temperature stable, low-loss, high-dielectric ceramic material and its preparation method, relating to electronic functional ceramic materials. The method includes preparing the material according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3,0.00≤ x ≤0.24, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form a complete feedstock. The feedstock is then ball-milled, dried, and sieved to form a sieved material. The sieved material is pressed into a green body, which is then sintered to obtain a wide-temperature stable, low-loss, high-dielectric ceramic. This solves the problems of high loss, low stability, large leakage current, and low breakdown field strength caused by high-temperature oxygen vacancy migration. The ceramic material prepared by this invention not only has high-temperature stability, high dielectric constant, and low dielectric loss and relaxation characteristics, but also has a simple preparation process, low material cost, and is environmentally friendly, making it an important candidate material that is both technically and economically superior to lead-based ceramic materials for high-end industrial applications.

Description

Technical Field

[0001] This invention relates to the field of electronic functional ceramic materials, specifically to a wide-temperature stable, low-loss, high-dielectric ceramic material and its preparation method. Background Technology

[0002] Sodium bismuth titanate (Na) 0.5 Bi 0.5 TiO3 (NBT)-based lead-free ceramics have promising applications in high-temperature capacitors due to their excellent ferroelectric properties and high-temperature stability. However, pure NBT materials face two key challenges that limit their energy storage applications: firstly, NBT exhibits strong ferroelectricity and weak relaxation, resulting in a wide hysteresis loop and low remanent polarization (P0). r High Na+ content leads to low energy storage efficiency (typically below 70%), with a large amount of energy dissipated as hysteresis losses; secondly, high-temperature Na+... + Bi 3+ Volatilization and oxygen vacancies (V Activation migration leads to a decrease in volume resistivity and an increase in leakage current, limiting the operating field strength and breakdown field strength. To address these issues, a (1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 By constructing a binary solid solution of TiO3 and tuning it to near the quasi-isomorphic phase boundary (MPB), the dielectric response can be effectively improved. However, the construction of a simple MPB structure is insufficient to suppress high-temperature oxygen vacancy migration losses, and the dielectric temperature stability is still inadequate. Therefore, how to achieve low loss and temperature stability while maintaining a high dielectric constant remains a current technical challenge. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention aims to provide a wide-temperature stable, low-loss, high-dielectric ceramic material and its preparation method, which solves the problems of high loss, low stability, large leakage current and low breakdown field strength caused by high-temperature oxygen vacancy migration.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: A wide-temperature stable, low-loss, high-dielectric ceramic material, with the stoichiometric formula: 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, where 0.00≤ x ≤0.24.

[0005] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: According to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, 0.00≤ x ≤0.24, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 and LiTaO3 powders are mixed evenly to form the complete ingredients; Step 2: The complete batch of ingredients is ball-milled, dried, and sieved to form sieved material; Step 3: Press the sieved material into a green body and sinter the green body to obtain a wide-temperature stable, low-loss, high-dielectric ceramic.

[0006] Furthermore, in step 1, Na 0.5 Bi 0.5 TiO3 powder is obtained through the following steps: Weigh Na2CO3, Bi2O3 and TiO2 according to a molar ratio of 1:1:(3.5-4.5) and mix them to form mixture A. Take mixture A, zircon and deionized water and mix them according to a mass ratio of 1:(4.8-5.2):(0.8-1.2). Then, ball mill, dry and calcine at 850-860℃ for 3-4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 850-860℃ for 3-4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0007] Furthermore, in step 1, K 0.5 Bi 0.5 TiO3 powder is obtained through the following steps: K2CO3, Bi2O3 and TiO2 were weighed in a molar ratio of 1:1:(3.5-4.5) and mixed to form mixture C. Mixture C, zircon and deionized water were taken and mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2). The mixture was then ball-milled, dried and calcined at 950-960℃ for 3-4 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0008] Furthermore, the LiTaO3 powder in step 1 is obtained through the following steps: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of (0.8-1.2):(0.8-1.2) to form mixture E. Mixture E, zircon, and deionized water were taken and mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2). The mixture was then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain LiTaO3 powder.

[0009] Further, in step 2, the whole batch of ingredients is mixed with zircon and deionized water at a mass ratio of 1:(4.8-5.2):(0.8-1.2), then ball-milled and dried.

[0010] Furthermore, the ball milling time is 12-24 hours, followed by drying at 85-100℃ for 24 hours.

[0011] Furthermore, the mesh size of the sieve used in step 2 is 140-160 mesh.

[0012] Furthermore, the pressing process in step 3 specifically involves holding the pressure at 180-220 MPa for 2-4 minutes, then holding the pressure at 170-200 MPa for 4-6 minutes, and finally releasing the pressure at 30-50 MPa / min to form a blank through cold isostatic pressing.

[0013] Furthermore, the sintering in step 3 specifically involves first heating the furnace to 1100-1150°C for 210-230 minutes, holding the temperature for 2.5-3.5 hours, then cooling the furnace to 480-520°C for 110-130 minutes, and finally cooling the furnace to room temperature.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: The 0.9[(1-] prepared by the method of the present invention x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi0.5 TiO3]-0.1LiTaO3 ceramic material, utilizing (1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 The quasi-isomorphic phase boundary (MPB) of TiO3 (NKBT) under specific composition conditions can be adjusted by controlling the KBT content. x This allows the material to be positioned in a phase boundary region with a low energy barrier, thereby achieving high polarization intensity and dielectric constant. By introducing the low-loss microwave dielectric ceramic material lithium tantalate (LiTaO3), Li... + / Ta 5+ Entering the crystal lattice, Li compensates for oxygen vacancies caused by Bi volatilization, suppressing leakage conduction losses at high temperatures. + and Ta 5+ Occupying the A and B sites, the original long-range ordered ferroelectric structure is broken, thus forming polar nanodomains (PNRs). This improves the relaxation characteristics of the ceramic, making the change of the dielectric loss tangent tanδ with temperature more gradual, further suppressing the polarization response of ferroelectric domains and stabilizing dielectric properties. It not only possesses high-temperature stability, a high dielectric constant, and low dielectric loss and relaxation characteristics, but also features a simple preparation process, low material cost, and is environmentally friendly, making it an important candidate material that offers both technical and economic advantages as a replacement for lead-based ceramic materials in high-end industrial applications. Attached Figure Description

[0015] Figure 1 The XRD patterns of the ceramic materials prepared in Examples 1-6 of this invention are shown below. Figure 2 This is a comparison chart of the dielectric constants of the ceramic materials prepared in Examples 1-6 of this invention at 1 kHz. Figure 3 The graph shows the tanδ value of the dielectric loss tangent of the ceramic materials prepared in Examples 1-6 of this invention at 1 kHz. Figure 4 The temperature stability (T) of the ceramic materials prepared in Examples 1-6 of this invention. cc Comparison chart. Detailed Implementation The embodiments of the present invention will be described in further detail below: The purity of Na2CO3, K2CO3, Bi2O3, TiO2, Li2CO3, and Ta2O5 mentioned below is all above 99.0%, and a planetary ball mill is used for ball milling.

[0016] A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- xNa 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, 0.00≤ x ≤0.24.

[0017] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 and LiTaO3 powders, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, 0.00≤ x ≤0.24, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 and LiTaO3 powders are mixed evenly to form the complete ingredients; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out Na₂CO₃, Bi₂O₃, and TiO₂ in a molar ratio of 1:1:(3.5-4.5). 2， Mixing forms a mixture A. Mixture A, zircon, and deionized water are mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 850-860℃ for 3-4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 850-860℃ for 3-4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0018] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out K₂CO₃, Bi₂O₃, and TiO₂ in a molar ratio of 1:1:(3.5-4.5). 2，Mixing forms mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2). The mixture is then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0019] The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of (0.8-1.2):(0.8-1.2) to form mixture E. Mixture E, zircon, and deionized water were taken and mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2). The mixture was then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain LiTaO3 powder.

[0020] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:(4.8-5.2):(0.8-1.2), then ball mill and dry the mixture. Grind the dried material through a 140-160 mesh sieve. The ball milling time described in steps 1 and 2 above is 12-24 hours, followed by drying at 85-100℃ for 24 hours.

[0021] Step 3: The sieved material is first held under pressure at 180-220MPa for 2-4 minutes, then under pressure at 170-200MPa for 4-6 minutes, and finally depressurized at 30-50MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1100-1150℃ at 210-230min and held for 2.5-3.5h, then cooled to 480-520℃ at 110-130min and finally cooled to room temperature with the furnace to obtain a wide-temperature stable, low-loss, high-dielectric ceramic.

[0022] 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 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1-x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.00.

[0023] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.00, weigh Na 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out Na₂CO₃, Bi₂O₃, and TiO₂ according to a molar ratio of 1:1:3.5. 2， Mixtures are combined to form mixture A. Mixture A, zircon, and deionized water are mixed in a mass ratio of 1:4.8:0.8, and then ball-milled, dried, and calcined at 850°C for 3 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:4.8:0.8, and then ball-milled, dried, and calcined at 850°C for 3 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0024] The preparation of LiTaO3 powder is as follows: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 1:1 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:4.8:0.8 and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:4.8:0.8, and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain LiTaO3 powder.

[0025] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:4.8:0.8, then ball mill and dry the mixture. Grind the dried material through a 140-mesh sieve. The ball milling time described in steps 1 and 2 above is 12 hours, followed by drying at 85°C for 24 hours; Step 3: The sieved material is first pressed at 180MPa for 2 minutes, then at 170MPa for 4 minutes, and finally depressurized at 30MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1100℃ in 210 minutes and held for 2.5 hours, then lowered to 480℃ in 110 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0026] The sintered sample obtained in step 3 (grinding and cleaning) was then uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with a zirconium oxide pad, and then the alumina crucible was placed in a box furnace and sintered at 650°C for 24 minutes to obtain 0.9Na. 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0027] Example 2 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.16.

[0028] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.16, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Na₂CO₃, Bi₂O₃, and TiO₂ were weighed according to a molar ratio of 1:1:4. 2， Mixtures are combined to form mixture A. Mixture A, zircon, and deionized water are mixed in a mass ratio of 1:5:1 and then ball-milled, dried, and calcined at 855°C for 3.5 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:5:1, and then ball-milled, dried, and calcined at 855°C for 3.5 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0029] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out K2CO3, Bi2O3 and TiO2 according to a molar ratio of 1:1:3.5. 2， Mixtures are combined to form mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:5:1 and then ball-milled, dried, and calcined at 950°C for 3.5 hours to obtain powder D. Powder D was mixed with zircon and deionized water in a mass ratio of 1:5:1, and then ball-milled, dried, and calcined at 950°C for 3.5 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0030] The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 1:0.8 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:5:1 and then ball-milled, dried, and calcined at 955°C for 3.5 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:5:1, and then ball-milled, dried, and calcined at 955°C for 3.5 hours to obtain LiTaO3 powder.

[0031] Step 2: Mix the prepared ingredients with zircon and deionized water in a mass ratio of 1:5:1, then ball mill and dry the mixture. Grind the dried material through a 150-mesh sieve. The ball milling time described in steps 1 and 2 above is 16 hours, followed by drying at 90°C for 24 hours; Step 3: The sieved material is first pressed at 200MPa for 2 minutes, then at 180MPa for 5 minutes, and finally depressurized at 30MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1125℃ in 225 minutes and held for 3 hours, then cooled to 500℃ in 120 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0032] The sintered sample obtained in step 3, after grinding and cleaning, was uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with zirconium oxide as a backing plate. Then, the alumina crucible was placed in a box furnace and sintered at 650°C for 24 min to obtain 0.9[0.84Na]. 0.5 Bi 0.5 TiO3-0.16K 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0033] Example 3 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.18.

[0034] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.18, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out Na₂CO₃, Bi₂O₃, and TiO₂ according to a molar ratio of 1:1:4.5. 2， Mixture A is formed by mixing. Mixture A, zircon, and deionized water are mixed in a mass ratio of 1:5.2:1.2 and then ball-milled, dried, and calcined at 860°C for 4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:5.2:1.2, and then ball-milled, dried, and calcined at 860°C for 4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0035] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out K2CO3, Bi2O3 and TiO2 according to a molar ratio of 1:1:3.5. 2， Mixtures are combined to form mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:5.2:1.2 and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain powder D. Powder D was mixed with zircon and deionized water in a mass ratio of 1:5.2:1.2, and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0036] The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 0.8:1 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:5.2:1.2 and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:5.2:1.2, and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain LiTaO3 powder.

[0037] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:5.2:1.2, then ball mill and dry the mixture. Grind the dried material through a 160-mesh sieve. The ball milling time described in steps 1 and 2 above is 24 hours, followed by drying at 100℃ for 24 hours; Step 3: The sieved material is first pressed at 220MPa for 2 minutes, then at 200MPa for 6 minutes, and finally depressurized at 40MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1150℃ in 230 minutes and held for 3.5 hours, then lowered to 500℃ in 130 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0038] The sintered sample obtained in step 3, after grinding and cleaning, was uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with zirconium oxide as a backing plate. Then, the alumina crucible was placed in a box furnace and sintered at 650°C for 24 min to obtain 0.9[0.82Na]. 0.5 Bi 0.5 TiO3-0.18K 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0039] Example 4 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.20.

[0040] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.20, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Na₂CO₃, Bi₂O₃, and TiO₂ were weighed according to a molar ratio of 1:1:4. 2， Mixture A is formed by mixing. Mixture A, zircon and deionized water are mixed in a mass ratio of 1:4.8:1 and then ball-milled, dried and calcined at 850°C for 4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:4.8:1, and then ball-milled, dried, and calcined at 850°C for 4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0041] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: K₂CO₃, Bi₂O₃, and TiO₂ were weighed according to a molar ratio of 1:1:4. 2， Mixtures are combined to form mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:4.8:1 and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:4.8:1, and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0042] The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 1:1 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:4.8:1 and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:4.8:1, and then ball-milled, dried, and calcined at 950°C for 3 hours to obtain LiTaO3 powder.

[0043] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:4.8:1, then ball mill and dry the mixture. Grind the dried material through a 160-mesh sieve. The ball milling time described in steps 1 and 2 above is 12 hours, followed by drying at 85°C for 24 hours; Step 3: The sieved material is first pressed at 180MPa for 3 minutes, then at 170MPa for 5 minutes, and finally depressurized at 40MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1100℃ in 210 minutes and held for 2.5 hours, then lowered to 500℃ in 125 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0044] The sintered sample obtained in step 3, after grinding and cleaning, was uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with zirconium oxide as a backing plate. Then, the alumina crucible was placed in a box furnace and sintered at 650°C for 24 min to obtain 0.9[0.80Na]. 0.5 Bi 0.5 TiO3-0.20K 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0045] Example 5 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.22.

[0046] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.22, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out Na₂CO₃, Bi₂O₃, and TiO₂ according to a molar ratio of 1:1:4.5. 2， Mixture A is formed by mixing, and then mixing the mixture A, zircon and deionized water in a mass ratio of 1:5:1.2. The mixture is then ball-milled, dried and calcined at 855°C for 3.5 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:5:1.2, and then ball-milled, dried, and calcined at 855°C for 3.5 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0047] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Weigh out K2CO3, Bi2O3 and TiO2 according to a molar ratio of 1:1:4.5. 2， Mixtures are combined to form mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:5:1.2 and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:5:1.2, and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder; The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 1:1.2 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:5:1.2 and then ball-milled, dried, and calcined at 955°C for 3.5 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:5:1.2, and then ball-milled, dried, and calcined at 955°C for 3.5 hours to obtain LiTaO3 powder.

[0048] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:5:1.2, then ball mill and dry. Grind the dried material through a 150-mesh sieve. The ball milling time described in steps 1 and 2 above is 16 hours, followed by drying at 90°C for 24 hours; Step 3: The sieved material is first pressed at 200MPa for 2.5 minutes, then at 180MPa for 5 minutes, and finally depressurized at 50MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1125℃ in 220 minutes and held for 3 hours, then lowered to 520℃ in 125 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0049] The sintered sample obtained in step 3, after grinding and cleaning, was uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with zirconium oxide as a backing plate. Then, the alumina crucible was placed in a box furnace and sintered at 650°C for 24 min to obtain 0.9[0.78Na]. 0.5 Bi 0.5 TiO3-0.22K 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0050] Example 6 A wide-temperature stable, low-loss, high-dielectric ceramic material with a stoichiometric formula of 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.24.

[0051] A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material includes the following steps: Step 1: Preparation of Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder, according to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, x =0.24, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Among them, Na 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: Na₂CO₃, Bi₂O₃, and TiO₂ were weighed according to a molar ratio of 1:1:4. 2， Mixture A is formed by mixing. Mixture A, zircon and deionized water are mixed in a mass ratio of 1:5.2:1 and then ball-milled, dried and calcined at 860°C for 4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:5.2:1, and then ball-milled, dried, and calcined at 860°C for 4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

[0052] Among them, K 0.5 Bi 0.5 The preparation of TiO3 powder is as follows: K₂CO₃, Bi₂O₃, and TiO₂ were weighed according to a molar ratio of 1:1:4. 2， Mixtures are combined to form mixture C. Mixture C, zircon, and deionized water are mixed in a mass ratio of 1:5.2:1 and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:5.2:1, and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

[0053] The preparation of LiTaO3 powder specifically involves: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of 1.2:1 to form mixture E. Mixture E, zircon, and deionized water were mixed in a mass ratio of 1:5.2:1 and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:5.2:1, and then ball-milled, dried, and calcined at 960°C for 4 hours to obtain LiTaO3 powder.

[0054] Step 2: Mix the prepared ingredients with zircon and deionized water at a mass ratio of 1:5.2:1, then ball mill and dry. Grind the dried material through a 160-mesh sieve. The ball milling time described in steps 1 and 2 above is 24 hours, followed by drying at 100℃ for 24 hours; Step 3: The sieved material is first pressed at 220MPa for 2 minutes, then at 200MPa for 6 minutes, and finally depressurized at 50MPa / min to form a green body by cold isostatic pressing; in a box furnace, the temperature is first raised to 1150℃ in 225 minutes and held for 3.5 hours, then lowered to 520℃ in 130 minutes and finally cooled to room temperature with the furnace to obtain ceramics.

[0055] The sintered sample obtained in step 3, after grinding and cleaning, was uniformly coated with silver electrode paste on both sides. The sample coated with silver electrodes was placed in an alumina crucible with zirconium oxide as a backing plate. Then, the alumina crucible was placed in a box furnace and sintered at 650°C for 24 min to obtain 0.9[0.76Na]. 0.5 Bi 0.5 TiO3-0.24K 0.5 Bi 0.5 TiO3-0.1LiTaO3 ceramic.

[0056] XRD tests were performed on the samples prepared in Examples 1-6 to obtain... Figure 1 result, Figure 1 It is 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 XRD patterns of ceramics in the TiO3-0.1LiTaO3 system. From... Figure 1 It can be seen that the synthesized ceramic sample exhibits a typical perovskite phase structure, with sharp and symmetrical diffraction peaks. This indicates that the introduction of LiTaO3 did not disrupt the main crystal phase structure of the NBT-based ceramic, and its dissociated Li + With NBT lattice A-site Na + Bi 3+ Formation of radius-matched substitution solid solutions, Ta 5+ Then Ti occupies position B 4+ Lattice sites, Li + / Ta 5+ The dual-site doping did not induce lattice distortion and also improved the lattice compatibility of the NKBT binary system, making KBT's K + The LiTaO3 phase successfully diffused into the NBT-LiTaO3 matrix lattice to form a continuous solid solution. The modification of LiTaO3 enabled the construction of a high-purity perovskite phase in NBT-based ceramics, avoiding the negative impact of impurities on ceramic densification and electrical properties, and laying a stable crystal structure foundation for improving the dielectric properties of the material.

[0057] Figure 2 It is 0.9[(1- x Na 0.5 Bi0.5 TiO3- x K 0.5 Bi 0.5 The dielectric constant of the TiO3-0.1LiTaO3 ceramic samples varies with temperature. The results show that the introduction of LiTaO3 and the quasi-isomorphic phase boundary (MPB) modulation by KBT have a synergistic effect, achieving a high dielectric constant and a low temperature-sensitive characteristic. LiTaO3 doping disrupts the intrinsic ferroelectric long-range ordered structure of NBT, forming a large number of polar nanoregions (PNRs), which significantly enhance the rapid polarization response under an electric field. Simultaneously, LiTaO3 compensates for oxygen vacancies generated by Bi volatilization, blocking polarization relaxation losses caused by oxygen vacancy migration and effectively improving the effective polarization intensity of the material. Combined with the MPB effect regulated by KBT, the coexistence of crystal phases at the phase boundary further enhances the polarization freedom, enabling all samples to maintain a high dielectric constant level in the range of 50–500 °C.

[0058] Figure 3 It is 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 The dielectric loss tangent (tanδ) of the TiO3-0.1LiTaO3 ceramic samples varies with temperature. The results show that the samples with x=0.16 and 0.24 exhibit tanδ as low as 0.006~0.044 at 50℃, and show no significant increase in tanδ within the 50~500℃ range, maintaining a consistently low loss level. This indicates that the introduction of LiTaO3 reduces the dielectric loss tangent (tanδ) of the LiTaO3 ceramic sample. + / Ta 5+ By incorporating the lattice according to stoichiometry, oxygen vacancy charge defects are compensated through valence balance, reducing the number of mobile oxygen vacancies, thereby blocking leakage conduction channels and suppressing high-temperature leakage conduction losses.

[0059] Figure 4 It is 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 Temperature stability (T) of TiO3-0.1LiTaO3 ceramic samples cc ).from Figure 4 It can be seen that all ceramic samples exhibit excellent dielectric temperature stability. x Ceramic samples with a coefficient of 0.00-0.24 have a wide operating temperature range (50–500℃) and meet the requirements of T. ccThe variation requirement is ≤±15%. This indicates that the PNRs formed after the introduction of LiTaO3 have excellent thermal stability, and oxygen vacancy compensation effectively suppresses performance degradation at high temperatures, preventing abrupt decay of the material's dielectric properties; the evaluation standard is raised to T... cc Even with stringent requirements of ≤±10%, samples with x=0.16 and 0.24 can still fully meet the requirements, and the rate of change of dielectric constant remains relatively flat with increasing temperature.

[0060] In summary, this invention modulates Na 0.5 Bi 0.5 TiO3 and K 0.5 Bi 0.5 The high proportion of TiO3 positions the main crystalline phase within the quasi-isomorphic phase boundary (MPB) region, leveraging the enhanced polarization activity at the phase boundary to establish a high dielectric constant. Furthermore, LiTaO3 is innovatively introduced as a modifier. The incorporation of LiTaO3 compensates for oxygen vacancies, blocking leakage channels, while simultaneously disrupting the intrinsic long-range ordered structure of NBTs to form polar nanoregions. This synergistic effect significantly suppresses dielectric loss and enhances dielectric temperature stability. This invention features a simple process and produces ceramic materials with excellent overall performance, showing promising application prospects in the field of dielectric energy storage.

Claims

1. A wide-temperature stable, low-loss, high-dielectric ceramic material, characterized in that, The stoichiometric formula is: 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, where 0.00≤ x ≤0.

24.

2. A method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material, characterized in that, Includes the following steps: Step 1: According to the stoichiometric formula 0.9[(1- x Na 0.5 Bi 0.5 TiO3- x K 0.5 Bi 0.5 TiO3]-0.1LiTaO3, 0.00≤ x ≤0.24, weigh Na 0.5 Bi 0.5 TiO3 powder, K 0.5 Bi 0.5 TiO3 powder and LiTaO3 powder are mixed evenly to form the complete formula; Step 2: The complete batch of ingredients is ball-milled, dried, and sieved to form sieved material; Step 3: Press the sieved material into a green body, and sinter the green body to obtain a wide-temperature stable, low-loss, high-dielectric ceramic.

3. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, Na in step 1 0.5 Bi 0.5 TiO3 powder is obtained through the following steps: Weigh Na2CO3, Bi2O3 and TiO2 in a molar ratio of 1:1:(3.5-4.5) and mix them to form mixture A. Take mixture A, zircon and deionized water and mix them in a mass ratio of 1:(4.8-5.2):(0.8-1.2). Then, ball mill, dry and calcine at 850-860℃ for 3-4 hours to obtain powder B. Powder B was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 850-860℃ for 3-4 hours to obtain Na. 0.5 Bi 0.5 TiO3 powder.

4. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, In step 1, K 0.5 Bi 0.5 TiO3 powder is obtained through the following steps: Weigh K2CO3, Bi2O3 and TiO2 in a molar ratio of 1:1:(3.5-4.5) and mix them to form mixture C. Take mixture C, zircon and deionized water and mix them in a mass ratio of 1:(4.8-5.2):(0.8-1.2). Then, ball mill, dry and calcine at 950-960℃ for 3-4 hours to obtain powder D. The powder D was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain K. 0.5 Bi 0.5 TiO3 powder.

5. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, The LiTaO3 powder in step 1 is obtained through the following steps: Li2CO3 and Ta2O5 were weighed and mixed in a molar ratio of (0.8-1.2):(0.8-1.2) to form mixture E. The mixture, zircon, and deionized water were mixed in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain powder F. The powder F was mixed with zircon and deionized water in a mass ratio of 1:(4.8-5.2):(0.8-1.2), and then ball-milled, dried, and calcined at 950-960℃ for 3-4 hours to obtain LiTaO3 powder.

6. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, In step 2, the whole batch of ingredients is mixed with zircon and deionized water at a mass ratio of 1:(4.8-5.2):(0.8-1.2), then ball-milled and dried.

7. A wide-temperature stable, low-loss, high-dielectric ceramic material according to any one of claims 3, 4, 5, or 6 Preparation method, characterized in that, The ball milling time is 12-24 hours, followed by drying at 85-100℃ for 24 hours.

8. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, The sieve used in step 2 has a mesh size of 140-160.

9. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, The pressing process in step 3 specifically involves holding the pressure at 180-220 MPa for 2-4 minutes, then holding the pressure at 170-200 MPa for 4-6 minutes, and finally releasing the pressure at 30-50 MPa / min to form a blank through cold isostatic pressing.

10. The method for preparing a wide-temperature stable, low-loss, high-dielectric ceramic material according to claim 2, characterized in that, The sintering in step 3 specifically involves first heating the furnace to 1100-1150°C for 210-230 minutes, holding the temperature for 2.5-3.5 hours, then cooling the furnace to 480-520°C for 110-130 minutes, and finally cooling the furnace to room temperature.

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