阅读说明：本技术 一种铋基棒状结构巨介电陶瓷材料及制备方法 (Bismuth-based rod-shaped structure giant dielectric ceramic material and preparation method thereof ) 是由 高攀 陈昕 张方晖 于 2021-10-22 设计创作，主要内容包括：本发明公开了一种铋基棒状结构巨介电陶瓷材料及制备方法,属于介电陶瓷材料及巨介电陶瓷介电电容器领域,该陶瓷材料的制备采用一定量的MgO和WO-(3)制备出混合物A再将得到的混合物A分别与锆球石和酒精按1:1:1比例混合,依次进行球磨、烘干、预烧后形成化学有序的MgWO-(4)粉体；将Bi-(2)O-(3)和该粉体混合依次进行球磨、烘干、造粒、过筛后压制成试样,在空气中800～1000℃保温2～4h随炉冷却至室温,最后对试样正反两面涂覆银浆即可,制备方法简单、成本低。本发明方法制得的无铅巨介电陶瓷材料呈棒状结构、致密性较好,且具有巨介电的特点,适合巨介电材料在高密度存储器件中的广泛应用。(The invention discloses a bismuth-based rodlike giant dielectric ceramic material and a preparation method thereof, belonging to the field of dielectric ceramic materials and giant dielectric ceramic dielectric capacitors 3 Preparing a mixture A, mixing the mixture A with zircon and alcohol according to a ratio of 1:1:1, ball-milling, drying and presintering in sequence to form chemically ordered MgWO 4 Powder; adding Bi 2 O 3 Mixing the powder, ball milling, drying, granulating, sieving and pressing into a sample, and keeping the temperature of 800-1000 ℃ in the air for 2-4 hAnd cooling to room temperature along with the furnace, and finally coating silver paste on the front and back surfaces of the sample, wherein the preparation method is simple and low in cost. The lead-free giant dielectric ceramic material prepared by the method has a rod-shaped structure, has good compactness and giant dielectric characteristic, and is suitable for wide application of the giant dielectric material in high-density memory devices.)

1. The bismuth-based rodlike structure giant dielectric ceramic material is characterized in that the bismuth-based rodlike structure giant dielectric ceramic material comprises Bi (Mg)_1/2W_1/2)O₃The bismuth-based rod-shaped giant dielectric ceramic material has a rod-shaped structure and a dielectric constant of 0-3.5 multiplied by 10⁶。

2. The preparation method of the bismuth-based rod-like structure giant dielectric ceramic material of claim 1, which is characterized by comprising the following steps:

the method comprises the following steps: mixing MgO with WO₃Mixing to obtain a mixture A;

step two: ball-milling, drying and heat-preserving the mixture A in sequence to form MgWO₄Powder;

step three: adding Bi₂O₃And MgWO₄Mixing the powder, and then sequentially performing ball milling, drying, granulation and sieving to form granules;

step four: pressing the granulated material into a sample, cooling to room temperature after sintering, and then polishing and cleaning to obtain a pretreated sample;

step five: and uniformly coating silver electrode slurry on the front surface and the back surface of the pretreated sample, and sintering to obtain the bismuth-based rod-like structure giant dielectric ceramic material.

3. The method for preparing bismuth-based rod-like structure giant dielectric ceramic material according to claim 2, wherein in the first step, MgO and WO are added₃The molar ratio is (1+ b): 1, wherein b is 0.02-0.04.

4. The preparation method of the bismuth-based rod-shaped giant dielectric ceramic material according to claim 2, wherein in the second step, the mixture A is respectively mixed with zircon and alcohol according to the mass ratio of 1:1: 1;

ball milling time is 12 hours, drying time is 2-3 hours, drying temperature is 80-100 ℃, heat preservation is carried out for 9-11 hours at 950-1050 ℃, and MgWO is formed₄And (3) powder.

5. The preparation method of the bismuth-based rod-shaped giant dielectric ceramic material according to claim 2, wherein MgWO is added in the third step₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a), wherein a is 0.01-0.03; b is 0.02-0.04;

the ball milling time is 12 h; the drying time is 2-3 h, and the drying temperature is 80-100 ℃.

6. The bismuth-based rod-shaped giant dielectric ceramic material and the preparation method thereof as claimed in claim 2, wherein in the third step, the granulation and the sieving are carried out by adding adhesive with mass concentration of 4-6% into the material, and sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain the intermediate material.

7. The method for preparing the bismuth-based rod-structured giant dielectric ceramic material according to claim 6, wherein the binder is an aqueous solution of polyvinyl alcohol.

8. The preparation method of the bismuth-based rod-shaped giant dielectric ceramic material according to claim 2, wherein in the fourth step, the granulated material obtained in the third step is pressed into a sample under the pressure of 6-8 MPa.

9. The preparation method of the bismuth-based rod-shaped giant dielectric ceramic material as claimed in claim 2, wherein in the fourth step, when the sample is sintered, the temperature is raised to 550-600 ℃ at a rate of 3-5 ℃/min from room temperature, then the temperature is preserved for 100-120 min, the temperature is raised to 800-1000 ℃ continuously, then the temperature is preserved for 2-4 h, then the temperature is lowered to 300-400 ℃ at a rate of 3-5 ℃/min, and then the sample is cooled to room temperature along with the furnace.

10. The preparation method of the bismuth-based rod-shaped giant dielectric ceramic material according to claim 2, wherein in the fifth step, the sintering temperature is 550-650 ℃, and the sintering time is 30-40 min.

Technical Field

The invention belongs to the field of dielectric ceramic materials and giant dielectric ceramic dielectric capacitors, and relates to a bismuth-based rod-like giant dielectric ceramic material and a preparation method thereof.

Background

With the continuous development of the microelectronic industry, higher requirements are put forward on miniaturization, integration and lightness and thinness of electronic equipment, and dielectric materials are important components of microelectronic devices. The development of dielectric ceramics having high dielectric constants, low dielectric losses, good frequency and temperature stability is a great trend. Accordingly, giant dielectric materials are receiving increasing attention from researchers.

The dielectric materials frequently used at present are Ba-based, Pb-based relaxor ferroelectrics. At room temperature, these ceramic materials have a relatively high dielectric constant of about 10²～10³The dielectric loss is less than 0.1 and relatively small. But also has the disadvantage that the dielectric constant of these materials changes too strongly with temperature. For example, BaTiO₃At T_cThe dielectric constant is 6000-10000 at 120 ℃, and the change is severe compared with 1400 at room temperature. The Pb-based relaxor ferroelectric ceramic contains Pb element, heavy metal element Pb has great harm to the environment and even human body, so that a lead-free material is always searched for to replace the Pb-free ferroelectric ceramic, Bi and Pb are close to each other in many aspects of performance and are green metal harmless to the human body, and therefore Bi can be used as a preferred material for replacing Pb.

Researchers expect that giant dielectric materials will develop towards high dielectric constant and low dielectric loss, but in practice, the giant dielectric materials cannot be obtained at the same time, and the higher the dielectric constant, the higher the dielectric loss is. Therefore, researchers try to achieve the effect that dielectric loss can be further reduced while ultrahigh dielectric constant is obtained by means of doping modification and the like. By changing the combination of the doped ions, the performance, the structure and the like of the ceramic can be effectively improved. Cheng et al successfully prepared (A) by conventional solid phase method_0.5Nb_0.5)_xTi_1-xO₂The result of (A ═ Bi, Pr, Dy, Sm, Gd, Yb and Sc) ceramic shows that the ceramic has giant dielectric property, wherein (Bi, Nb) is codoped with TiO₂The dielectric properties of the ceramic are optimal. Zhao et Al found (Al, Sm, Bi, Fe, In, Dy, Ga, Gd, Yb, Sc) + (Ta, Sb) codoped TiO₂Also has macro mediumAn electrical constant. No Bi (Mg) prepared by the invention is seen at present_1/2W_1/2)O₃Ceramic materials and methods for their preparation are reported.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a bismuth-based rod-shaped giant dielectric ceramic material and a preparation method thereof, and aims to solve the technical problems that the ceramic material in the prior art has high preparation cost, lead-containing materials pollute the environment, and the giant dielectric ceramic material is not suitable for being applied to a large range of high-density memory devices.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the invention provides a bismuth-based rod-shaped structure giant dielectric ceramic material, which comprises the following components of Bi (Mg)_1/2W_1/2)O₃The bismuth-based rod-shaped giant dielectric ceramic material has a rod-shaped structure and a dielectric constant of 0-3.5 multiplied by 10⁶。

The invention provides a preparation method of a bismuth-based rodlike structure giant dielectric ceramic material, which comprises the following steps:

the method comprises the following steps: mixing MgO with WO₃Mixing to obtain a mixture A;

step two: ball-milling, drying and heat-preserving the mixture A in sequence to form MgWO₄Powder;

step three: adding Bi₂O₃And MgWO₄Mixing the powder, and then sequentially performing ball milling, drying, granulation and sieving to form granules;

step four: pressing the granulated material into a sample, cooling to room temperature after sintering, and then polishing and cleaning to obtain a pretreated sample;

step five: and uniformly coating silver electrode slurry on the front surface and the back surface of the pretreated sample, and sintering to obtain the bismuth-based rod-like structure giant dielectric ceramic material.

Preferably, in step one, MgO and WO₃The molar ratio is (1+ b): 1, wherein b is 0.02-0.04.

Preferably, in the second step, the mixture A is respectively mixed with zircon and alcohol according to the mass ratio of 1:1: 1;

ball milling time is 12 hours, drying time is 2-3 hours, drying temperature is 80-100 ℃, heat preservation is carried out for 9-11 hours at 950-1050 ℃, and MgWO is formed₄And (3) powder.

Preferably, in step three, MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a), wherein a is 0.01-0.03; b is 0.02-0.04;

the ball milling time is 12 h; the drying time is 2-3 h, and the drying temperature is 80-100 ℃.

Preferably, in the third step, the granulation and the sieving are performed by adding a binder with the mass concentration of 4-6% into the mixture for granulation, and sieving the mixture with a 60-mesh sieve and a 80-mesh sieve respectively to obtain the intermediate material.

Preferably, the binder is an aqueous solution of polyvinyl alcohol.

Preferably, in the fourth step, the granulated material obtained in the third step is pressed into a sample under the pressure of 6-8 MPa.

Preferably, in the fourth step, when the sample is sintered, the temperature is raised to 550-600 ℃ at a rate of 3-5 ℃/min from room temperature, the temperature is kept for 100-120 min, the temperature is continuously raised to 800-1000 ℃, the temperature is kept for 2-4 h, the temperature is reduced to 300-400 ℃ at a rate of 3-5 ℃/min, and then the sample is cooled to room temperature along with the furnace.

Preferably, in the fifth step, the sintering temperature is 550-650 ℃, and the sintering time is 30-40 min.

Compared with the prior art, the invention has the following beneficial effects:

the bismuth-based rod-shaped structure giant dielectric ceramic material provided by the invention is of a rod-shaped structure, and the crystal grains of a bismuth-based rod-shaped structure giant dielectric ceramic material sample are tightly combined, and almost no gap appears, so that the bismuth-based rod-shaped structure giant dielectric ceramic material has good compactness and giant dielectric characteristics, and can realize the application of the giant dielectric material in a high-density memory.

The preparation method of the bismuth-based rodlike structure giant dielectric ceramic material provided by the invention adopts the traditional solid phase method to prepare the material by mixing MgO and WO₃Mixing to form a mixture A, and then ball-milling, drying and presintering the obtained mixture A in sequence to form a chemically ordered mixtureMgWO₄Powder; adding Bi₂O₃Mixing the bismuth-based rod-like structure giant dielectric ceramic powder with the powder, sequentially performing ball milling, drying, granulating, sieving and pressing to form a sample, sintering the sample, cooling to room temperature, and coating silver paste on the front surface and the back surface of the sample to obtain the bismuth-based rod-like structure giant dielectric ceramic material. The invention adopts a two-step solid-phase sintering method to prepare the ceramic material, and MgWO is prepared firstly₄The powder realizes the chemical order of the ceramic material, and excessive Bi is added₂O₃And the template induces the grain to grow directionally, so that the grains are basically consistent in orientation. MgO and WO adopted in the preparation method of the giant dielectric ceramic material₃And Bi₂O₃The material cost is low, and the method is suitable for mass production; in addition, ball milling, drying, granulating and sieving are carried out on the prepared product, the traditional sintering process is adopted, the preparation method is simple, the time consumption is short, and the method is suitable for large-scale application of the giant dielectric material in a high-density storage device.

Furthermore, the product prepared by granulation can be more abundant and solid, and the structure is more delicate; the polyvinyl alcohol aqueous solution can increase the viscosity of the product and ensure good formability of the product.

Drawings

FIG. 1 is a graph showing the dielectric constant at 10KHz as a function of sintering temperature for examples 7 to 9 of the present invention;

FIG. 2 is an SEM spectrum of examples 7 to 9 of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

the invention relates to a preparation method of a bismuth-based rodlike structure giant dielectric ceramic material, which comprises the following steps:

example 1:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.01, and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 2:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.01, and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 3:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.03.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.03.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.01, and b is 0.03;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 4:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.03.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing the mixture to form a mixture A,wherein b is 0.03.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in turn, and then preserving heat at 1050 ℃ for 11h to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.01, and b is 0.03;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 8MPa, then placing the sample into a high-temperature box type furnace for sintering, raising the temperature to 600 ℃ at the speed of 5 ℃/min, then preserving the heat for 120min, continuing raising the temperature to 900 ℃, preserving the heat for 4h, then reducing the temperature to 400 ℃ at the speed of 5 ℃/min, and then cooling the sample to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 6% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 650 ℃ for 40min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 5:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball milling, drying and manufacturing in sequenceGranulating and sieving to form granules, wherein a is 0.01, and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 6:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.01 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.01, and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 7:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.02 and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 8:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.02 and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 9:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in turn, and then preserving heat at 1050 ℃ for 11h to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.02 and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 8MPa, then placing the sample into a high-temperature box type furnace for sintering, raising the temperature to 600 ℃ at the speed of 5 ℃/min, then preserving the heat for 120min, continuing raising the temperature to 900 ℃, preserving the heat for 4h, then reducing the temperature to 400 ℃ at the speed of 5 ℃/min, and then cooling the sample to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 6% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 650 ℃ for 40min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 10:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.03.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.03.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in turn, and then preserving heat at 1050 ℃ for 11h to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving in sequence to form the finished productPellets, wherein a is 0.02 and b is 0.03;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 8MPa, then placing the sample into a high-temperature box type furnace for sintering, raising the temperature to 600 ℃ at the speed of 5 ℃/min, then preserving the heat for 120min, continuing raising the temperature to 900 ℃, preserving the heat for 4h, then reducing the temperature to 400 ℃ at the speed of 5 ℃/min, and then cooling the sample to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 6% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 650 ℃ for 40min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 11:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.02 and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 12:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.02 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.02 and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 13:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.03, and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 14:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.02.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.02.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.03, and b is 0.02;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 15:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.03.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.03.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a ═0.03，b＝0.03；

Step four: pressing the granulated material obtained in the third step into a sample under the pressure of 8MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 5 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 5 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 6% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 16:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.03.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.03.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in turn, and then preserving heat at 1050 ℃ for 11h to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.03, and b is 0.03;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 8MPa, then placing the sample into a high-temperature box type furnace for sintering, raising the temperature to 600 ℃ at the speed of 5 ℃/min, then preserving the heat for 120min, continuing raising the temperature to 900 ℃, preserving the heat for 4h, then reducing the temperature to 400 ℃ at the speed of 5 ℃/min, and then cooling the sample to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 3h, and the drying temperature is 100 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 6% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 650 ℃ for 40min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 17:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, ball-milling, drying, and keeping the temperature at 950 ℃ for 9 hours to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.03, and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 6MPa, then placing the sample into a high-temperature box type furnace for sintering, heating to 550 ℃ at the speed of 3 ℃/min, then preserving heat for 100min, continuing heating to 800 ℃, preserving heat for 2h, cooling to 300 ℃ at the speed of 3 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2h, and the drying temperature is 80 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 4% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 550 ℃ for 30min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

Example 18:

the bismuth-based rodlike structure giant dielectric ceramic material of the invention and the formula MgWO thereof₄And Bi₂O₃The powder molar ratio is (1+ b): (1+ a), wherein a is 0.03 and b is 0.04.

The method comprises the following steps: according to the molar ratio of (1+ b): 1 weighing MgO and WO₃Mixing to form a mixture a, wherein b is 0.04.

Step two: taking the mixture A, respectively mixing with zircon and alcohol according to the mass ratio of 1:1:1, then carrying out ball milling and drying in sequence, and then preserving heat for 10 hours at 1000 ℃ to form MgWO₄Powder for later use;

step three: MgWO₄Powder and Bi₂O₃According to the molar ratio of (1+ b): (1+ a) mixing, ball-milling, drying, granulating and sieving to form granules, wherein a is 0.03, and b is 0.04;

step four: pressing the granulated material obtained in the third step into a sample under the pressure of 7MPa, then placing the sample in a high-temperature box type furnace for sintering, heating to 580 ℃ at the speed of 4 ℃/min, then preserving heat for 110min, continuing heating to 850 ℃, preserving heat for 3h, cooling to 350 ℃ at the speed of 4 ℃/min, and then cooling to room temperature along with the high-temperature box type furnace;

in the third step and the fourth step, the ball milling time is 12 hours; the drying time is 2.5h, and the drying temperature is 90 ℃; sieving with 60 mesh sieve and 80 mesh sieve respectively to obtain intermediate material; granulating and sieving, namely adding a binding agent with the mass concentration of 5% into the mixture for granulation;

step five: and (4) polishing and cleaning the sample sintered in the fourth step, uniformly coating silver electrode slurry on the front surface and the back surface of the sample, and sintering at 600 ℃ for 35min to obtain the bismuth-based rod-shaped structure giant dielectric ceramic material sample.

FIG. 1 is a graph showing the dielectric constant of the samples of examples 7 to 9 at 10KHz as a function of different sintering temperatures. It can be observed from the figure that the dielectric constant is increased with the increasing sintering temperature, and the dielectric coefficient value is 0-3.5 multiplied by 10⁶The peak value is reached between 700 and 800 ℃, and the dielectric constant value reaches 10⁶The material is described as a giant dielectric material which has not been found before.

FIG. 2 is a schematic view of(a) And (b) SEM spectra of samples of examples 7-9, it is seen from FIG. 2 that the sample surface is very dense, the grains are rod-like structures, and the growth orientation is substantially consistent, mainly due to the addition of excessive Bi₂O₃So that the crystal grains grow directionally.

The invention discloses a bismuth-based rodlike structure giant dielectric ceramic material and a preparation method thereof. Bi (Mg) used as component of bismuth-based rod-shaped giant dielectric ceramic material_1/2W_1/2)O₃And (4) showing. The invention adopts a two-step solid-phase sintering method to prepare the ceramic material, and MgWO is prepared firstly₄The powder realizes the chemical order of the ceramic material, and excessive Bi is added₂O₃The ceramic material prepared by the invention has the dielectric constant of 10⁶And the giant dielectric material has a rod-shaped structure, can be applied to a high-density memory, and has the advantages of simple preparation process, low cost and good application prospect.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.