Low dielectric loss giant dielectric ceramic and preparation method thereof

Abstract

The application relates to a low-dielectric-loss giant dielectric ceramic and a preparation method thereof, which comprises the following steps: ball milling: putting a perovskite giant dielectric ceramic powder, a dispersion medium and a ball milling medium into a ball milling tank for ball milling; granulation: adding polyvinyl alcohol aqueous solution to the slurry for granulation; aging: adding deionized water to uniformly mix and then aging to obtain a mixed powder; dry pressing: adopting a grinding tool and a press to press the mixed powder into a sheet-shaped ceramic with a certain thickness; cold isostatic pressing: performing cold isostatic pressing treatment on the sheet-shaped ceramic, placing the round sheet in air for standing, and then drying; sintering: moving the sheet-shaped ceramic into an oscillation sintering furnace, using a large-current oscillation pressure sintering process, applying oscillation pressure and a large current in different sintering stages, and obtaining the perovskite giant dielectric ceramic after cooling. The perovskite giant dielectric ceramic obtained by adopting the preparation method has the advantages of high dielectric constant and low dielectric loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of giant dielectric ceramics, in particular to a low dielectric loss giant dielectric ceramic and a preparation method thereof. BACKGROUND

[0002] Giant dielectric ceramic refers to a material with a relative dielectric constant of 10 4 The above dielectric ceramic material is an excellent new type of capacitor material. With the continuous popularization of new energy vehicles, new power grids and other aspects, the demand for giant dielectric ceramic materials will continue to increase. The most common ferroelectric giant dielectric ceramic is a perovskite material. The perovskite giant dielectric ceramic materials that were first put into industrial production are mainly Pb-based lead zirconate titanate (PbZr x Ti 1-x O3) and Ba x Sr 1-x TiO3) materials.

[0003] At present, several common perovskite giant dielectric ceramics such as BaTiO3, PbTiO3, SrTiO3, etc. can be prepared by solid phase sintering, hot pressing sintering (HP), hot isostatic pressing sintering (HIP), flash sintering (FS), and spark plasma sintering (SPS), each method has its advantages and disadvantages and applicability. The existing literature and patents related to the preparation technology of giant dielectric ceramics mainly include CN114262223A, CN115321976A and CN103214237B. The patent CN114262223A is about the preparation of TiO2-based giant dielectric ceramic by flash sintering. Compared with conventional sintering, the sintering time and temperature are significantly reduced, and giant dielectric ceramic with smaller grain size and more uniform structure can be obtained. Although this method improves the dielectric constant, it still has the problem of high dielectric loss; the patent CN115321976A uses a solid phase sintering process, i.e. adding Nd2O3 and Nb2O5 to the CCTO giant dielectric ceramic material, and through solid phase sintering, a ceramic material with giant dielectric constant and low dielectric loss is obtained, but the grain size cannot be guaranteed, which affects the mechanical properties of the product; the patent CN103214237B uses self-propagating high-temperature rapid pressing technology to sinter barium titanate ceramic, which improves the dielectric constant, but has high dielectric loss and large dielectric constant variation with temperature.

[0004] The giant dielectric ceramic samples prepared by the existing sintering technology have improved dielectric constant, but are accompanied by high dielectric loss, which greatly limits the development of the electronic material industry. SUMMARY

[0005] The main purpose of the present application is to provide a preparation method of giant dielectric ceramic with high dielectric constant and low dielectric loss.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of low dielectric loss giant dielectric ceramic, comprising the following steps:

[0008] (1) Ball milling: the perovskite giant dielectric ceramic powder, dispersion medium and ball milling medium are loaded into a ball milling tank, and the perovskite giant dielectric ceramic powder is ball milled by a ball mill at a first ball milling speed and a first ball milling time to obtain a slurry with uniform mixing;

[0009] (2) Granulation: polyvinyl alcohol aqueous solution is added to the slurry, and the slurry is ball milled for a second time at a second ball milling speed and a second ball milling time, then dried, ball milled for a third time, and sieved to obtain the crushed powder;

[0010] (3) Aging: deionized water is added to the crushed powder for humidification, so that the water and the powder are uniformly mixed, and then aging is started to obtain the mixed powder;

[0011] (4) Dry pressing: the mixed powder is pressed into a sheet-shaped ceramic with a certain thickness by using a die and a press at a first pressure for a first holding time;

[0012] (5) Cold isostatic pressing: the sheet-shaped ceramic after pressing is subjected to cold isostatic pressing treatment at a second pressure for a second holding time, and then placed in air for a certain time and dried;

[0013] (6) Sintering: the sheet-shaped ceramic after cold isostatic pressing is moved into an oscillation sintering furnace, and a large current oscillation pressure sintering process is used to apply oscillation pressure and large current in different sintering stages, and a perovskite giant dielectric ceramic with high dielectric constant and low dielectric loss is obtained after cooling.

[0014] The perovskite giant dielectric ceramic powder includes BaTiO3 powder, PbTiO3 powder or SrTiO3; the purity of the perovskite giant dielectric ceramic powder is ≥ 99.9%.

[0015] The dispersion medium is deionized water, the ball milling medium is zirconium oxide grinding balls with an addition ratio of φ10:φ5=(8-4):1; the ball milling tank is made of nylon or zirconium oxide with a volume of 250ml-500ml; the ball mill is a vertical planetary ball mill, the first ball milling speed is 300rpm-400rpm, and the first ball milling time is 2-4h; the weight ratio of the perovskite giant dielectric ceramic powder to the ball milling medium is 1:(2-5); and the weight ratio of the perovskite giant dielectric ceramic powder to the deionized water is 1:(2-3).

[0016] The concentration of the polyvinyl alcohol aqueous solution is 3wt.%-5wt.%, the mass percentage of the polyvinyl alcohol aqueous solution added to the slurry is 5wt.%-8wt.%, the second ball milling speed is 200-250rpm, and the second ball milling time is 1-2h.

[0017] Further, the slurry after the second ball milling is passed through a 20-80 mesh screen, then moved into an oven, dried at 60-100℃ for 24-48h, and the dried powder is poured into a nylon tank, then ball milled again at a speed of 60-100rpm for 0.5-1h according to the zirconium oxide ball ratio of 500g = Φ20(75g) + Φ10(390g) + Φ5(35g), and then the crushed powder is passed through a 20-100 mesh screen and loaded into a self-sealing bag.

[0018] The aging includes spraying deionized water to the crushed and sieved powder at a ratio of 1-3wt.% of deionized water to the crushed and sieved powder, then repeatedly inverting the self-sealing bag after spraying, the inverting frequency is not less than 20 times, so that the water can be uniformly mixed with the powder, and then aged for not less than 24h.

[0019] The first pressure is 60-75MPa, the first holding time is 0-1min; the second pressure is 200-250MPa, the second holding time is 3-7min; the round piece is placed in air for 50-90min, and then placed in a 60-100℃ oven for drying.

[0020] The sintering stage includes:

[0021] heating at a rate of 1-5℃ / min to 200℃;

[0022] heating from 200℃ to 1200℃ at a rate of 0.5-3.5℃ / min;

[0023] heating from 1200℃ to T max at a rate of 0.2-1℃ / min; max and keeping at T

[0024] cooling from T max to 1100℃ at a rate of 0.5-3.5℃ / min.

[0025] The using large current oscillating pressure sintering process includes the following steps:

[0026] in the heating stage at a rate of 1-5℃ / min to 200℃, applying an oscillating pressure of 10-30MPa, and passing a current of (0.5-1)×10 3 A;

[0027] at a rate of 0.5-3.5℃ / min from 200℃ to 1200℃, applying oscillation pressure of 30-60MPa, passing current of (1-2)×10 3 A;

[0028] at a rate of 0.2-1℃ / min from 1200℃ to T max , and keeping at T max ℃ for 6-10h, applying oscillation pressure of 40-60MPa, passing current of (2-4)×10 3 A;

[0029] at a rate of 0.5-3.5℃ / min from T max to 1100℃, without applying oscillation pressure, without passing current;

[0030] T max is 1300℃-1500℃.

[0031] The application also provides a low dielectric loss giant dielectric ceramic prepared according to the preparation method.

[0032] By the above technical solution, the application has at least the following advantages:

[0033] The application uses solid phase reaction method, and selects high-temperature and high-pressure oscillation sintering furnace as sintering furnace, so that the reaction is simple, easy to operate, the process is simple, and the cost is low. The application uses large-current oscillation pressure sintering process, and applies oscillation pressure and large current in different sintering stages. Due to the influence of oscillation pressure, the ceramic green body is continuously extruded in the process of grain growth, so that the grain becomes smaller and the domain wall increases. Under the action of large current, the electric domain presents orientation polarization phenomenon. After the large current is removed, the green body can still maintain high residual polarization. Finally, a perovskite giant dielectric ceramic with high dielectric constant and low dielectric loss can be obtained.

[0034] The above description is only a summary of the technical solution of the application. In order to more clearly understand the technical means of the application, and to implement the content of the description, the following will be described in detail with reference to the preferred embodiments of the application and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a comparison schematic diagram of high-temperature and high-pressure oscillation sintering curve and conventional sintering curve provided by the embodiments of the application. DETAILED DESCRIPTION

[0036] To further clarify the technical means and effects taken by the present application to achieve the intended purpose, the specific embodiments, structures, features and effects of the present application are described in detail below in conjunction with the drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0037] As Figure 1 shown, it is a comparison chart of conventional sintering curve and high temperature and high pressure oscillation sintering curve, the first curve 1 is the conventional sintering curve, the second curve 2 is the high temperature and high pressure oscillation sintering curve, and the third curve 3 is the oscillation pressure; from Figure 1 the comparison of the first curve 1 and the second curve 2+third curve 3 in the figure, it can be known that the dielectric loss of the giant dielectric ceramic obtained by the conventional sintering process of the first curve 1 is large; and in the high temperature and high pressure oscillation sintering process of the second curve 2+third curve 3, the oscillation pressure and the large current are applied at the same time in the heating process, that is, the ceramic green body grain growth process, the green body is constantly extruded, the grain size is small, and the domain wall is increased; under the action of the large current, the electric domain presents the oriented polarization phenomenon, and the green body can still maintain a high residual polarization after the large current is removed, so that the giant dielectric ceramic with small grain size and low dielectric loss can be obtained.

[0038] The present application will be further described below through specific embodiments:

[0039] The planetary ball mill is used in each embodiment of the present application, in order to bear the same weight at the symmetrical position and prevent the planetary ball mill from being eccentric and damaging the equipment, two ball milling tanks are arranged at the symmetrical position of the planetary ball mill, and the same amount of material is added to each ball milling tank.

[0040] Embodiment 1

[0041] (1) batching: 50g of BaTiO3 powder with a purity of 99.9%, 100g of deionized water, and 150g of zirconia grinding balls Φ10(100g)+Φ5(25g) are loaded into a φ250ml zirconia material ball milling tank of a planetary ball mill, and the same amount of BaTiO3 powder, deionized water and zirconia grinding balls are loaded into another φ250ml zirconia material ball milling tank at the symmetrical position of the planetary ball mill;

[0042] (2) ball milling: a planetary ball mill is used, the rotation speed is set to 300rpm, and the BaTiO3 powder is ball milled for 2h to obtain a ball milled slurry with uniform mixing;

[0043] (3) Granulation: The slurry was added with a 5 wt.% polyvinyl alcohol aqueous solution at a concentration of 5 wt.%, and the planetary ball mill was operated at 250 rpm for 1 h. The obtained slurry was filtered through a 20-mesh screen, and the filtered slurry was poured into a plastic basin, covered with a newspaper, and moved into an oven for drying at 60°C for 24 h. The dried powder was poured into a nylon jar with an outer size specification of Φ124x15, and zirconia grinding balls were added at a ratio of 500 g = Φ20 (75 g) + Φ10 (390 g) + Φ5 (35 g). The ball mill was operated at a speed of 60 rpm for 0.5 h to further crush the powder. The crushed powder was sieved through a 20-mesh screen and then loaded into a ziplock bag.

[0044] (4) Aging: Deionized water was added to the sieved BaTiO3 powder for humidification. The amount of deionized water added was 2 wt.% of the sieved BaTiO3 powder. The humidification process used a spraying technique, and after spraying, the ziplock bag was repeatedly inverted and turned over 28 times to ensure uniform mixing of the water and powder. The aging process lasted for 25 h.

[0045] (5) Dry pressing: A Φ50 die was used, and the pressing machine was operated at a pressure of 75 MPa for 5 min. The mixed powder was pressed into a circular sheet with a thickness of 5 mm.

[0046] (6) Cold isostatic pressing: The pressed circular sheet was subjected to cold isostatic pressing at a pressure of 230 MPa for 5 min to further improve the density of the green body. The circular sheet was placed in air for 1 h and then dried in a 60°C oven to obtain a BaTiO3 green body.

[0047] (7) Sintering: The BaTiO3 green body was sintered in a high-temperature and high-pressure oscillation sintering furnace. The temperature was raised to 200°C at a rate of 1°C / min, an oscillation pressure of 10 MPa was applied, and a current of 0.5x10 3 A was passed through. The temperature was raised from 200°C to 1200°C at a rate of 0.5°C / min, an oscillation pressure of 40 MPa was applied, and a current of 1.5x10 3 A was passed through. The temperature was raised from 1200°C to 1500°C at a rate of 1°C / min, and the temperature was maintained at 1500°C for 8 h. A current of 3x10 3A current, during the holding period, the oscillating pressure is reduced from 40 MPa to 30 MPa within 1 h from 0-1 h, the oscillating pressure is kept at 30 MPa within 2 h from 1-3 h, the oscillating pressure is increased from 30 MPa to 40 MPa within 1 h from 3-4 h, the oscillating pressure is reduced from 40 MPa to 30 MPa within 1 h from 4-5 h, the oscillating pressure is kept at 30 MPa within 1 h from 5-6 h, the oscillating pressure is increased from 30 MPa to 40 MPa within 2 h from 6-8 h; finally, the temperature is decreased from 1500 ℃ to 1100 ℃ at a rate of 2 ℃ / min, no oscillating pressure is applied, and no current is passed. Finally, a BaTiO3 giant dielectric ceramic material with a room temperature dielectric constant of 26826@1 kHz and a dielectric loss of 0.017@1 kHz is obtained.

[0048] Example 2

[0049] (1) Ingredients: take 100 g of SrTiO3 powder with a purity of 99.9%, 240 g of deionized water, 252 g of zirconia grinding balls Φ10 (216 g) + Φ5 (36 g) each two parts, respectively, are loaded into the two φ500 ml nylon material ball milling tanks in the symmetrical position of the planetary ball mill;

[0050] (2) Ball milling: the rotation speed of the planetary ball mill is set to 300 rpm, and the SrTiO3 powder is ball milled for 3 h to obtain a uniformly mixed slurry;

[0051] (3) Granulation: add 3wt.% polyvinyl alcohol aqueous solution to the slurry, the addition amount is 8wt.% of the slurry, planetary ball mill at 200 rpm, after 2 h, the obtained slurry is passed through an 80 mesh screen, poured into a plastic drying pan, covered with newspaper, and moved into an oven, dried at 100 ℃ for 30 h, the dried powder is poured into a nylon tank with an outer size of Φ124×150, the zirconia grinding ball ratio is 500 g = Φ20 (75 g) + Φ10 (390 g) + Φ5 (35 g), the ball milling speed is 100 rpm, and the ball milling time is 1 h to further crush the powder, the crushed powder is passed through a 100 mesh screen and loaded into a self-sealing bag;

[0052] (4) Aging: add deionized water to the crushed and sieved SrTiO3 powder for humidification, the addition amount of deionized water is 1wt.% of the crushed and sieved SrTiO3 powder, the humidification process adopts a spraying process, after spraying, the self-sealing bag is repeatedly inverted and turned over 20 times to ensure that the water is uniformly mixed with the powder, and the aging process starts, the aging time is 30 h.

[0053] (5) Dry pressing: a 50×50 mm die is used, the pressure of the press is 60 MPa, and the holding time is 1 min, the mixed powder is pressed into a square piece with a thickness of 5 mm;

[0054] (6) Cold isostatic pressing: the circular piece which has been pressed is treated by cold isostatic pressing with a pressure of 250 MPa for 3 min to further improve the density of the blank, and the circular piece is placed in air for 50 min and then dried in an oven at 80°C to obtain the SrTiO3 blank;

[0055] (7) Sintering: the SrTiO3 blank is sintered in a high-temperature and high-pressure oscillation sintering furnace, and the temperature is raised to 200°C at a rate of 5°C / min, an oscillation pressure of 30 MPa is applied, and a current of 0.5x10 3 A; the temperature is raised to 1200°C at a rate of 3.5°C / min, an oscillation pressure of 40 MPa is applied, and a current of 1x10 3 A; the temperature is raised to 1400°C at a rate of 1°C / min, and the temperature is maintained at 1400°C for 6 h, a current of 2x10 3 A is passed, and during the holding period, the oscillation pressure is reduced from 60 MPa to 40 MPa in the first 1 h, then maintained at 40 MPa in the second 1 h, increased from 40 MPa to 60 MPa in the third 1 h, reduced from 60 MPa to 40 MPa in the fourth 1 h, maintained at 40 MPa in the fifth 1 h, and increased from 40 MPa to 60 MPa in the sixth 1 h; and then the temperature is lowered to 1100°C at a rate of 1°C / min, no oscillation pressure is applied, and no current is passed. Finally, a SrTiO3 giant dielectric ceramic material with a room temperature dielectric constant of 25578@1 kHz and a dielectric loss of 0.023@1 kHz is obtained.

[0056] Example 3

[0057] (1) Blending: 50 g of PbTiO3 powder with a purity of 99.9% and 150 g of deionized water are taken, and 180 g of zirconia grinding balls, i.e. two Φ10 (160 g) and two Φ5 (20 g), are respectively placed in two φ250 ml zirconia ball mills in the symmetrical position of the planetary ball mill;

[0058] (2) Ball milling: the planetary ball mill is used, and the rotation speed is set to 300 rpm. The PbTiO3 powder is ball milled for 4 h to obtain a uniformly mixed slurry;

[0059] (3) Granulation: the slurry was added to a 4 wt.% polyvinyl alcohol aqueous solution at a concentration of 6 wt.%, and planetary ball milling was performed at 230 rpm for 1.5 h. The obtained slurry was passed through a 60-mesh screen, and then poured into a plastic drying pan, covered with newspaper, and moved into an oven for drying at 80°C for 48 h. The dried powder was poured into a nylon jar with a Φ124x15 size, and zirconia grinding balls were added in a ratio of 500 g = Φ20 (75 g) + Φ10 (390 g) + Φ5 (35 g). The ball milling speed was 80 rpm, and the ball milling time was 0.8 h. The ground powder was passed through a 40-mesh screen and then loaded into a self-sealing bag.

[0060] (4) Aging: deionized water was added to the ground and sieved PbTiO3 powder for humidification. The amount of deionized water added was 3 wt.% of the ground and sieved PbTiO3 powder. The humidification process used a spraying process, and after spraying, the self-sealing bag was repeatedly inverted and turned over 25 times to ensure that the water was uniformly mixed with the powder. The aging time was 24 h.

[0061] (5) Dry pressing: a Φ50 die was used, and the pressure of the press was 65 MPa. The holding time was 0 min, and the mixed powder was pressed into a circular sheet with a thickness of 5 mm.

[0062] (6) Cold isostatic pressing: the pressure was 200 MPa, and the holding time was 7 min. The already pressed circular sheet was subjected to cold isostatic pressing for further improvement of the density of the green body. The circular sheet was placed in air for 90 min and then placed in a 100°C oven for drying to obtain a PbTiO3 green body.

[0063] (7) Sintering: a high-temperature and high-pressure oscillation sintering furnace was used to sinter the PbTiO3 green body. The temperature was raised to 200°C at a rate of 3°C / min, an oscillation pressure of 20 MPa was applied, and a current of 1x10 3 A; the temperature was raised from 200°C to 1200°C at a rate of 2.5°C / min, an oscillation pressure of 60 MPa was applied, and a current of 1.5x10 3 A; the temperature was raised from 1200°C to 1300°C at a rate of 1°C / min, and held at 1300°C for 10 h, and a current of 3x10 3A current, during the holding period, the oscillating pressure is reduced from 60 MPa to 50 MPa in 1h of 0-1h, the oscillating pressure is kept at 50 MPa in 1h of 1-2h, the oscillating pressure is increased from 50 MPa to 60 MPa in 2h of 2-4h, the oscillating pressure is reduced from 60 MPa to 40 MPa in 1h of 4-5h, the oscillating pressure is kept at 40 MPa in 3h of 5-8h, the oscillating pressure is increased from 40 MPa to 60 MPa in 2h of 8-10h, then the temperature is decreased from 1300℃ to 1100℃ at a rate of 2℃ / min, no oscillating pressure is applied, and no current is passed. Finally, PbTiO3 giant dielectric ceramic material with a dielectric constant of 28965@1kHz and a dielectric loss of 0.017@1kHz at room temperature is obtained.

[0064] Comparative Example

[0065] Steps (1) to (6) are the same as those in Example 1, except that:

[0066] (7) Sintering: the ceramic green body after cold isostatic pressing is sintered in a conventional silicon molybdenum rod sintering furnace, the temperature is increased to 1500℃ at a rate of 3℃ / min, and the temperature is kept at 1500℃ for 8h; the temperature is decreased from 1500℃ to 1100℃ at a rate of 2℃ / min. Finally, BaTiO3 giant dielectric ceramic material with a dielectric constant of 18644@1kHz and a dielectric loss of 0.7@1kHz at room temperature is obtained.

[0067] The difference between the comparative example and Example 1 is that the comparative example does not use the large current oscillating pressure sintering process, while Example 1 applies oscillating pressure and large current in different sintering stages. Due to the influence of oscillating pressure, the ceramic green body is constantly extruded during the grain growth process, the grain size becomes smaller, and the domain wall increases. Under the action of large current, the electric domain presents oriented polarization phenomenon. After the large current is removed, the green body can still maintain a high residual polarization. By comparing the room temperature dielectric constant and dielectric loss of the two, the BaTiO3 giant dielectric ceramic material finally obtained in Example 1 of the present application has high dielectric constant and low dielectric loss.

[0068] The above description is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and equivalent embodiments with equivalent changes are equivalent. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still belong to the scope of the technical solution of the present application.

Claims

1. A method for preparing a low dielectric loss giant dielectric ceramic, characterized by: The method comprises the following steps: (1) Ball milling: put the perovskite giant dielectric ceramic powder, dispersion medium and ball milling medium into a ball milling tank, use a ball mill to ball mill the perovskite giant dielectric ceramic powder at a first ball milling speed and for a first ball milling time, and obtain a slurry with uniformly mixed ball milling; (2) Granulation: add polyvinyl alcohol aqueous solution to the slurry, ball mill the slurry for a second time at a second ball milling speed and for a second ball milling time, then dry, ball mill for a third time, and sieve to obtain the crushed powder; (3) Aging: add deionized water to the crushed powder to humidify, mix the water and the powder uniformly, and then start aging to obtain the mixed powder; (4) Dry pressing: use a die and a press to press the mixed powder into a sheet ceramic with a certain thickness at a first pressure for a first holding time; (5) Cold isostatic pressing: use a second pressure to cold isostatic press the sheet ceramic that has been pressed, place the round sheet in air for a second holding time, and then dry; (6) Sintering: move the cold isostatic pressed sheet ceramic into a vibration sintering furnace, use a large current vibration pressure sintering process to apply vibration pressure and a large current in different sintering stages, and obtain a perovskite giant dielectric ceramic with high dielectric constant and low dielectric loss after cooling. The perovskite giant dielectric ceramic powder comprises BaTiO3 powder, PbTiO3 powder or SrTiO3 powder; and the purity of the perovskite giant dielectric ceramic powder is greater than or equal to 99.9%.

2. The production method according to claim 1, characterized by, The dispersion medium is deionized water, the ball milling medium is zirconium oxide grinding balls with an addition ratio of Φ10:Φ5=(8-4):1, the ball milling tank is made of nylon or zirconium oxide with a capacity of 250ml-500ml, the ball mill is a vertical planetary ball mill, the first ball milling speed is 300rpm-400rpm, the first ball milling time is 2-4h, the weight ratio of the perovskite giant dielectric ceramic powder to the ball milling medium is 1:(2-5), and the weight ratio of the perovskite giant dielectric ceramic powder to the deionized water is 1:(2-3).

3. The preparation method according to claim 1, characterized in that, The concentration of the polyvinyl alcohol aqueous solution is 3wt.%-5wt.%, the mass percentage of the polyvinyl alcohol aqueous solution added to the slurry is 5wt.%-8wt.%, the second ball milling speed is 200-250rpm, and the second ball milling time is 1-2h.

4. The production method according to claim 1, characterized by, Sieve the slurry after the second ball milling through a 20-mesh-80-mesh screen, move the slurry into an oven, dry the slurry at 60℃-100℃ for 24h-48h, pour the dried powder into a nylon tank, according to the zirconium oxide grinding ball ratio 500g=Φ20(75g)+Φ10(390g)+Φ5(35g), ball mill the powder for a third time at a ball milling speed of 60rpm-100rpm for 0.5h-1h, sieve the crushed powder through a 20-100-mesh screen, and then pack the powder into a self-sealing bag.

5. The method of any one of claims 1-4, wherein, ​ 6. The preparation method according to claim 5, characterized in that, The aging includes spraying deionized water to the sieved powder at a ratio of 1-3wt.% of the deionized water to the sieved powder, and then repeatedly inverting the self-sealing bag for not less than 20 times, so that the water can be uniformly mixed with the powder, and then aging for not less than 24 hours.

7. The production method according to claim 6, wherein The first pressure is 60-75MPa, the first holding time is 0-1min; the second pressure is 200-250MPa, the second holding time is 3-7min; the time for the disc to be placed in air is 50-90min, and then the disc is placed in an oven at 60-100℃ for drying.

8. The preparation method according to claim 7, characterized in that, The sintering stage includes: heating at a heating rate of 1-5℃ / min to 200℃; heating at a rate of 0.5-3.5℃ / min from 200℃ to 1200℃; Ramp from 1200°C to T at 0.2-1 °C / min max and hold for 6-10 h at T max °C. T max Cooling to 1100°C.

9. The production method according to claim 8, characterized by, The sintering process using large current oscillating pressure includes the following steps: Rise at a rate of 1-5 °C / min to 200 °C, apply oscillating pressure 10-30 MPa, pass a current (0.5-1) x 10 3 A; The temperature is raised from 200°C to 1200°C at a rate of 0.5-3.5°C / min, an oscillating pressure of 30-60 MPa is applied, and a current of (1-2) x 10 3 A; The temperature is raised from 1200°C to T at a rate of 0.2-1°C / min max and held at T for 6-10 h, with an oscillating pressure of 40-60 MPa, a current of (2-4) x 10 max A applied. 3 A; Said from T max Cooling to 1100 °C, no oscillating pressure applied, no current passed; The T max is 1300°C - 1500°C.

10. A low dielectric loss giant dielectric ceramic, characterized by, Prepared by the preparation method according to any one of claims 1-9.

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