阅读说明：本技术 一种高储能高效率的NaNbO3掺杂BaTiO3基氧化物陶瓷材料、制备方法及应用 (High-energy-storage high-efficiency NaNbO3Doped BaTiO3Base oxide ceramic material, preparation method and application ) 是由 蒲永平 宁亚婷 张贤 张金波 上阳超 于 2021-08-12 设计创作，主要内容包括：一种高储能高效率的NaNbO-(3)掺杂BaTiO-(3)基氧化物陶瓷材料、制备方法及应用,其化学式为(1-x)(0.6BaTiO-(3)-0.4Bi-(0.5)Na-(0.5)TiO-(3))-xNaNbO-(3),其中0≤x≤0.2,x为摩尔百分比。该陶瓷材料根据化学式配料并进行预烧球磨制备。制备所得的陶瓷材料可制作陶瓷产品。本发明所制备的陶瓷材料,具有明显的弥散相变特征,制备工艺简单,制作成本低,通过选择适当的x值,可使放电储能密度达到2.2J/cm～(3),同时储能效率达到91.7％,提供了一种新的无铅储能材料基体。(High-energy-storage high-efficiency NaNbO 3 Doped BaTiO 3 A base oxide ceramic material with a chemical formula of (1-x) (0.6 BaTiO), its preparation method and application 3 ‑0.4Bi 0.5 Na 0.5 TiO 3 )‑xNaNbO 3 Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent. The ceramic material is prepared by burdening according to a chemical formula and performing presintering and ball milling. The prepared ceramic material can be used for manufacturing ceramic products. The ceramic material prepared by the invention has obvious dispersion phase change characteristic, simple preparation process and low preparation cost, and can ensure that the discharge energy storage density reaches 2.2J/cm by selecting proper x value 3 Meanwhile, the energy storage efficiency reaches 91.7 percent, and a novel lead-free energy storage material matrix is provided.)

1. High-energy-storage high-efficiency NaNbO₃Doped BaTiO₃A base oxide ceramic material characterized by having a chemical formula of (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent.

2. Ceramic material according to claim 1, characterized in that the components consist of Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅And (4) introducing.

3. Process for the preparation of a ceramic material according to any one of claims 1 to 2, characterized in that it comprises the following steps:

according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent; taking Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅And (3) burdening, presintering, ball-milling and drying to obtain ceramic material powder.

4. The method for preparing a ceramic material according to claim 3, wherein the pre-firing temperature is 850 ℃ to 1000 ℃.

5. The method for producing a ceramic material according to claim 4, wherein the pre-firing system is: heating to the presintering temperature at the speed of 5 ℃/min, preserving heat for 2 hours, then cooling to 500 ℃ at the speed of 5 ℃/min, and furnace-cooling to room temperature.

6. A method of preparing a ceramic material as claimed in claim 3, wherein the batch is ball milled and then pre-fired.

7. Use of the ceramic material according to any of claims 1 to 2 for the manufacture of ceramic products.

8. Use of the ceramic material according to claim 7 for the manufacture of a ceramic product, wherein the sintering temperature is 1150 ℃.

Technical Field

The invention relates to the technical field of relaxor ferroelectrics, in particular to (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃A high-power-density high-entropy perovskite oxide ceramic material, a preparation method and application thereof.

Background

In order to meet the needs of electric vehicles and impulse weapons, the research of advanced energy storage devices has received wide attention from countries throughout the world. Compared with energy storage systems such as batteries, the ferroelectric capacitor has the advantages of high charging and discharging speed, high power density, long service life and the like. Improvement of the energy storage characteristics of ferroelectric capacitors the dielectric properties of the materials cannot be separated. Although there have been many important work reports, efficient energy storage ferroelectric materials with temperature stability are still lacking. The relaxor ferroelectric has zero remanent polarization (P) in an ideal state_r) And high saturation polarization (P)_s) The application of energy storage is more and more emphasized. However, most of the relaxor ferroelectrics contain lead, which causes great damage to the environment during the preparation and use processes, and therefore, development of a lead-free relaxor ferroelectric system is required.

Disclosure of Invention

The invention aims to provide NaNbO with high energy storage and high efficiency₃Doped BaTiO₃The ceramic capacitor material prepared by the method has the advantages of simple preparation process, low material cost, higher dielectric constant, low dielectric loss and good temperature stability, and can possibly become an important candidate material which replaces a lead-based ceramic material and becomes a multilayer ceramic capacitor with excellent technical and economic aspects.

The technical problem to be solved by the invention is to pass NaNbO₃(NN for short) 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃(BT-NBT for short) base material is modified to obtain (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃As relaxor ferroelectric materialsAnd has a lower remanent polarization compared to a general ferroelectric material. NaNbO₃The addition of the N can effectively enhance the relaxation property of the sample and improve the energy storage efficiency of the sample, because the doping of the NN can weaken the polar rhombohedral phase of the BT-NBT ceramic and reduce the residual polarization, thereby obtaining good energy storage performance. Furthermore, NN itself has a high Curie temperature (370 ℃) and a very complex phase transition sequence. Considering these inherent characteristics of NN, the addition of NN may interfere with the coupling of PNRs, thereby affecting the response time of PNRs, and ultimately increasing 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃High temperature stability of the ceramic. Thus, NaNbO₃The doping modification can enhance the breakdown field strength and the energy storage efficiency.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

high-energy-storage high-efficiency NaNbO₃Doped BaTiO₃A base oxide ceramic material with a chemical formula of (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent.

Preferably, the components consist of Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅And (4) introducing.

The invention also provides a preparation method of the ceramic material powder, which is characterized by comprising the following steps:

according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent; taking Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅And (3) burdening, presintering, ball-milling and drying to obtain ceramic material powder.

Preferably, the prefiring temperature is 850 ℃.

Preferably, the burn-in regime is: heating to 850 deg.C at 5 deg.C/min, holding for 2 hr, cooling to 500 deg.C at 5 deg.C/min, and furnace cooling to room temperature.

Preferably, the batch materials are ball milled and then pre-fired. High-energy-storage high-efficiency NaNbO₃Doped BaTiO₃A base oxide ceramic material having a chemical formula of (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is NaNbO₃The doping amount of (A) is more than or equal to 0 and less than or equal to 0.2, wherein x represents mole percent.

The invention also provides an application of the ceramic material in the preparation of ceramic products. The ceramic material powder is used for manufacturing ceramic products by processes of forming, sintering and the like of the electrodes, and the sintering temperature of the ceramic products is 1150 ℃.

Compared with the prior art, the invention has the following beneficial results: the invention uses NaNbO₃Doped with 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃In the matrix material, through the formula design, the quinquevalent Nb ion is verified to be 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The B position of (A) is substituted by tetravalent Ti ions. NaNbO₃The addition of the N can effectively enhance the relaxation property of the sample and improve the energy storage efficiency of the sample, because the doping of the NN can weaken the polar rhombohedral phase of the BT-NBT ceramic and reduce the residual polarization, thereby obtaining good energy storage performance. Furthermore, NN itself has a high Curie temperature (370 ℃) and a very complex phase transition sequence. Considering these inherent characteristics of NN, the addition of NN may interfere with the coupling of PNRs, thereby affecting the response time of PNRs, and ultimately increasing 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃High temperature stability of the ceramic. Therefore, the NN doping modification can enhance breakdown strength and energy storage density. Further, by the B-site Nb⁵⁺The relaxation degree can be further increased by doping, so that the electric hysteresis loop is refined, and the energy storage efficiency of the ceramic material is improved. Compared with the materials modified by the previous similar method, the material prepared by the invention has more excellent energy storage performance.

In the preparation process of the sample, a more advanced cold isostatic pressing technology is adopted, the waste of the sample and the addition of the binder are avoided, the manufacturing cost is saved, the production period is accelerated, the possibility of sample pollution caused by the binder is avoided, the step of removing the binder is reduced in the subsequent steps, the waste of resources and the waste of manufacturing time are reduced, in addition, the cold isostatic pressing technology utilizes liquid to transmit pressure, compared with the traditional single-item pressing, the cold isostatic pressing can enable the sample to be stressed from all directions, the pressure is higher, the prepared green body is more compact, and the foundation is laid for the next excellent experimental result.

In addition, with the enhancement of environmental awareness of people, the production of materials avoids the influence on the environment, and the raw materials adopted by the invention are environment-friendly because the raw materials do not contain heavy metal elements such as lead and the like, so the preparation process cannot damage the environment. The material prepared by the method has good compactness, no obvious air holes and uniform grain size, so the method can ensure that the NaNbO is in a uniform state₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃Has excellent energy storage and charge-discharge performance.

Drawings

FIG. 1 shows (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃When x is 0,0.03,0.06,0.10,0.15 and 0.20 in the ceramic material components, the XRD pattern of the ceramic material powder body;

FIG. 2 shows (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0,0.03,0.06,0.10,0.15,0.20) the polarization versus electric field profile of the ceramic material;

FIG. 3 shows (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃The energy storage density, the breakdown field strength and the energy storage efficiency of the ceramic are along with the change curve of the doping amount;

FIG. 4 shows (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃The temperature coefficient of the ceramic capacitor changes with the temperature.

Detailed Description

The present invention will be described in detail below with reference to the drawings and examples, but the present invention is not limited to the following examples.

In the invention, NaNbO is prepared₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃A ceramic material. Its chemical formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x is more than or equal to 0 and less than or equal to 0.2, and x is mole percent. For each element, Na is analytically pure₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅And (4) introducing.

Example one

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) when x is 0, the chemical formula is 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃According to the chemical formula, taking Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 1000 ℃ for 2 hours, wherein the presintering system comprises the following steps: heating to 1000 ℃ at a speed of 5 ℃/min, preserving heat for 2 hours, then cooling to 500 ℃ at a speed of 5 ℃/min, and cooling to room temperature along with the furnace to obtain a massive solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. Sieving the product with a 120-mesh sieve to obtain 0.6BaTiO with uniform size₃-0.4Bi_0.5Na_0.5TiO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃Weighing 0.35g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) taking the obtained sample out of the rubber sleeve, sintering the sample in a box type furnace at 1150 ℃ for 2 hours to form porcelain, and obtaining 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃A ceramic material.

Example two

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.03.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0.03) analytically pure Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 850 ℃ for 2 hours, wherein the presintering system comprises the following steps: heating to 850 deg.C at 5 deg.C/min, holding for 2 hr, cooling to 500 deg.C at 5 deg.C/min, and furnace coolingTo room temperature. Obtaining a blocky solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. Sieving the product with 120 mesh sieve to obtain 0.97(0.6 BaTiO) with uniform size₃-0.4Bi_0.5Na_0.5TiO₃)-0.03NaNbO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained 0.97(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.03NaNbO₃Weighing 0.38g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) the obtained sample was taken out of the rubber sleeve and sintered at 1150 ℃ for 2 hours in a box furnace to obtain 0.97(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.03NaNbO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.97(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.03NaNbO₃A ceramic material.

EXAMPLE III

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.06.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0.06) analytically pure Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 850 ℃ for 2 hours, wherein the presintering system comprises the following steps: heating to 850 deg.C at 5 deg.C/min, holding for 2 hr, cooling to 500 deg.C at 5 deg.C/min, and furnace cooling to room temperature. Obtaining a blocky solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. The product was sieved through a 120 mesh sieve to obtain 0.94(0.6 BaTiO) of uniform size₃-0.4Bi_0.5Na_0.5TiO₃)-0.06NaNbO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained 0.94(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.06NaNbO₃Weighing 0.36g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) the obtained sample was taken out of the rubber sleeve and sintered at 1150 ℃ for 2 hours in a box furnace to obtain 0.94(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.06NaNbO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.94(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.06NaNbO₃A ceramic material.

Example four

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.1.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0.1) analytically pure Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 850 ℃ for 2 hours, wherein the presintering system comprises the following steps: heating to 850 deg.C at 5 deg.C/min, holding for 2 hr, cooling to 500 deg.C at 5 deg.C/min, and furnace cooling to room temperature. Obtaining a blocky solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. Sieving the product with 120 mesh sieve to obtain 0.9(0.6 BaTiO) with uniform size₃-0.4Bi_0.5Na_0.5TiO₃)-0.1NaNbO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained 0.9(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.1NaNbO₃Weighing 0.38g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) taking out the obtained sample from the rubber sleeve and placing the sample in a boxSintering in a furnace at 1150 ℃ for 2 hours to obtain 0.9(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.1NaNbO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.9(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.1NaNbO₃A ceramic material.

EXAMPLE five

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.15.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0.15) analytically pure Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 850 ℃ for 2 hours, wherein the presintering system comprises the following steps: heating to 850 ℃ at the speed of 5 ℃/min, preserving heat for 2 hours, then cooling to 500 ℃ at the speed of 5 ℃/min, and cooling to room temperature along with the furnace to obtain a massive solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. Sieving the product with 120 mesh sieve to obtain 0.85(0.6 BaTiO) with uniform size₃-0.4Bi_0.5Na_0.5TiO₃)-0.15NaNbO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained product was 0.85 (0.6B)aTiO₃-0.4Bi_0.5Na_0.5TiO₃)-0.15NaNbO₃Weighing 0.35g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) the obtained sample was taken out of the rubber sleeve and sintered at 1150 ℃ for 2 hours in a box furnace to obtain 0.85(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.15NaNbO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.85(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.15NaNbO₃A ceramic material.

EXAMPLE six

1. Preparation of ceramic materials

The chemical formula of the ceramic material is as follows: (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃Wherein x represents a mole percentage, and x is 0.2.

The NaNbO mentioned above₃Doped 0.6BaTiO₃-0.4Bi_0.5Na_0.5TiO₃The preparation method of the ceramic material comprises the following steps:

(1) according to the formula (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x ═ 0.2) analytically pure Na₂CO₃、Bi₂O₃、BaCO₃、TiO₂And Nb₂O₅After preparation, the zirconium ball stone and deionized water are mixed according to the mass ratio of 1:5:1 and then ball-milled for 8 hours. Drying the mixture at 80 ℃ for 36 hours, grinding the mixture, placing the mixture in a muffle furnace for presintering at 850 ℃ for 2 hours, wherein the presintering system comprises the following steps: at 5 ℃/min literHeating to 850 ℃, preserving heat for 2 hours, then cooling to 500 ℃ at the speed of 5 ℃/min, and cooling to room temperature along with the furnace to obtain a blocky solid;

(2) and crushing the blocky solid, mixing the blocky solid with zircon and deionized water according to the mass ratio of 1:5:1, and then ball-milling for 8 hours. Sieving the product with 120 mesh sieve to obtain 0.8(0.6 BaTiO) with uniform size₃-0.4Bi_0.5Na_0.5TiO₃)-0.2NaNbO₃Powder;

2. preparation of ceramic test specimens for testing

(3) The obtained 0.8(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.2NaNbO₃Weighing 0.36g of powder per part by mass, pouring the powder into a mold, applying 600N force, and demolding the molded wafer to obtain a sample with a perfect shape;

(4) placing the wafer in a rubber sleeve, discharging air in the rubber sleeve by using a vacuumizing device, sealing a rubber sleeve opening, placing the rubber sleeve opening into a cold isostatic pressing mold, and maintaining the pressure at 200Mpa for 300 s;

(5) the obtained sample was taken out of the rubber sleeve and sintered at 1150 ℃ for 2 hours in a box furnace to obtain 0.8(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.2NaNbO₃A sample of dielectric ceramic material;

(6) polishing and cleaning the ceramic sample sintered once in the step (5), uniformly coating silver electrode slurry on the front surface and the back surface of the ceramic sample, and performing heat treatment at 550 ℃ for 25min to obtain 0.8(0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-0.2NaNbO₃A ceramic material.

The test specimens of examples 1 to 6 were tested.

Referring to FIG. 1, FIG. 1 is an XRD curve of a sample prepared by the above six examples, and from FIG. 1, it can be seen that the ceramic material (1-x) (0.6 BaTiO)₃-0.4Bi_0.5Na_0.5TiO₃)-xNaNbO₃(x is 0,0.03,0.06,0.10,0.15,0.20) under different doping amounts, pure phase ceramic materials are synthesized.

Referring to FIGS. 2 and 3, the above six embodiments are illustrated in FIG. 2The values of the hysteresis loop of the test sample are shown in FIG. 3, which are calculated from FIG. 2. As can be seen from fig. 2, as the NN doping amount increases, the hysteresis loop gradually "refines" and the remanent polarization significantly decreases. As can be seen from fig. 3, compared with the composition x ═ 0, the breakdown field intensity Eb is increased after the NN is doped, the hysteresis loop is refined, and the energy storage efficiency of the ceramic material is obviously increased. When x is 0.15, the energy storage density Wrec is 2.2J/cm³The energy storage efficiency η is 91.7%.

Referring to fig. 4, fig. 4 is a temperature coefficient versus temperature curve of the samples prepared in the above six examples. It can be seen from fig. 4 that the curve with X ═ 0.15 components shows good stability in the temperature range from-55 ℃ to 125 ℃, very close to the X7R standard.