CN115304369A - Preparation method of high-dielectric high-breakdown strontium titanate ceramic - Google Patents
Preparation method of high-dielectric high-breakdown strontium titanate ceramic Download PDFInfo
- Publication number
- CN115304369A CN115304369A CN202210233072.5A CN202210233072A CN115304369A CN 115304369 A CN115304369 A CN 115304369A CN 202210233072 A CN202210233072 A CN 202210233072A CN 115304369 A CN115304369 A CN 115304369A
- Authority
- CN
- China
- Prior art keywords
- strontium titanate
- titanate ceramic
- breakdown
- dielectric
- preparing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
- C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
- C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
- C04B35/47—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on strontium titanates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6567—Treatment time
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/77—Density
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
- C04B2235/786—Micrometer sized grains, i.e. from 1 to 100 micron
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
Abstract
The invention discloses a preparation method of high-dielectric high-breakdown strontium titanate ceramic, belonging to the technical field of ceramic material preparation. The preparation method comprises the following steps: preparing a strontium titanate ceramic blank; heating the strontium titanate ceramic blank to 1000-1150 ℃, and preserving heat for 30min at the temperature of 1000-1150 ℃; applying a constant-voltage electric field with the strength of 250V/cm to two ends of the strontium titanate ceramic blank after heat preservation until flash burning occurs, and then controlling the current density to be increased to 10-30 mA/mm 2 And continuously carrying out flash firing for 30-120S, and then finishing the flash firing to obtain the high-dielectric high-breakdown strontium titanate ceramic. The preparation method provided by the invention obviously shortens the sintering time and reduces the sintering temperature by carrying out flash sintering of technological parameters such as control voltage, current density and the like after short-time high-temperature preheating, and inhibits the sintering temperature under the condition of keeping high densificationThe grain growth of the prepared ceramic is realized, and the dielectric and breakdown characteristics of the strontium titanate ceramic are improved.
Description
Technical Field
The invention belongs to the technical field of ceramic material preparation, and particularly relates to a preparation method of high-dielectric high-breakdown strontium titanate ceramic.
Background
The ceramic dielectric capacitor is used as a common energy storage element in a pulse power system, and can be widely applied to the fields of military weapons, aerospace, electric automobiles, medical equipment and the like due to the advantages of high power density, fast charging and discharging speed, long cycle life and the like. However, as electronic devices gradually enter the age of miniaturization and miniaturization, the energy storage density of dielectric materials is urgently required to be improved.
Strontium titanate ceramics, a typical linear dielectric material, not only exhibits a paraelectric phase at room temperature, but also exhibits excellent electrical properties such as extremely low dielectric loss (< 1%), relatively high breakdown strength (> 200 kV/cm), and medium dielectric constant (-300), and has attracted much attention in dielectric capacitor applications.
However, the existing preparation of strontium titanate ceramics generally needs to be carried out for a long time (more than 2 h) at high temperature (1350-1500 ℃), the abnormal growth of crystal grains can be caused by long-time high-temperature treatment, the breakdown performance of the ceramics is seriously deteriorated, the improvement of the energy storage density is further limited, and the whole preparation process consumes more energy and time, so that the problems of excessive energy consumption, aggravation of environmental pollution and the like are caused.
Disclosure of Invention
The invention aims to provide a preparation method of high-dielectric high-breakdown strontium titanate ceramic, which comprises the steps of heating a strontium titanate ceramic blank to 1000-1150 ℃, carrying out heat preservation treatment for 30min, applying a constant-voltage electric field of 250V/cm until flash-firing occurs, and then controlling the current density to be increased to 10-30 mA/mm 2 And the flash firing is continued, so that the technical problem that the energy consumption and the time consumption are consumed for preparing the strontium titanate ceramic at present are solved, and the technical problem of abnormal growth of ceramic grains is solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
the embodiment of the invention provides a preparation method of high-dielectric high-breakdown strontium titanate ceramic, which comprises the following steps:
preparing a strontium titanate ceramic blank;
heating the strontium titanate ceramic blank to 1000-1150 ℃, and preserving heat for 30min at the temperature of 1000-1150 ℃;
applying a constant-voltage electric field with the strength of 250V/cm to two ends of the strontium titanate ceramic blank after heat preservation until flash burning occurs, and then controlling the current density to be increased to 10-30 mA/mm 2 And continuously carrying out flash firing, and ending the flash firing after 30-120S to obtain the high-dielectric high-breakdown strontium titanate ceramic.
As a further improvement of the embodiment of the present invention, the preparing of the strontium titanate ceramic body comprises:
preparing strontium titanate ceramic powder by taking strontium carbonate and titanium dioxide as raw materials;
and sequentially carrying out secondary ball milling, secondary drying, sieving and pressing on the strontium titanate ceramic powder to obtain a strontium titanate ceramic green body.
As a further improvement of the embodiment of the present invention, the preparing the strontium titanate ceramic body further includes:
and carrying out cold isostatic pressing treatment on the strontium titanate ceramic blank, wherein the pressure of the cold isostatic pressing is controlled to be 200Mpa, and the pressure maintaining time is 3min.
As a further improvement of the embodiment of the present invention, the preparation of strontium titanate ceramic powder using strontium carbonate and titanium dioxide as raw materials comprises:
weighing raw materials of strontium carbonate and titanium dioxide according to the stoichiometric ratio of strontium titanate, and then mixing and ball-milling the raw materials of strontium carbonate and titanium dioxide, zirconia ball stone and deionized water according to the mass ratio of 1;
drying the mixed raw materials subjected to ball milling at the temperature of 80 ℃, and then calcining for 2 hours at the temperature of 1200 ℃ to obtain the strontium titanate ceramic powder.
As a further improvement of the embodiment of the invention, the time for carrying out secondary ball milling on the strontium titanate ceramic powder is 8-12 h; the temperature for the secondary drying was 80 ℃.
As a further improvement of the embodiment of the invention, the standard mesh number of the strontium titanate ceramic powder sieved is 120-200 meshes.
As a further improvement of the embodiment of the invention, the heating rate of the strontium titanate ceramic blank is 10 ℃/min.
As an embodiment of the inventionOne-step improvement, the control current density is increased to 10-30 mA/mm 2 Completed within a period of 1S.
As a further improvement of the embodiment of the invention, the breakdown strength of the high-dielectric high-breakdown strontium titanate ceramic is 370kV/cm; the energy storage density is 2.21J/cm 3 。
As a further improvement of the embodiment of the invention, the dielectric constant of the high-dielectric high-breakdown strontium titanate ceramic at 1kHz is 380, and the dielectric loss is 0.008.
One or more technical solutions provided in the embodiments of the present invention have the following technical effects or advantages:
the preparation method of the high-dielectric high-breakdown strontium titanate ceramic provided by the embodiment of the invention comprises the steps of heating a strontium titanate ceramic blank to 1000-1150 ℃ and carrying out heat preservation treatment for 30min, then applying a constant voltage electric field of 250V/cm until flash-firing occurs, and then controlling the current density to increase to 10-30 mA/mm 2 And continuously carrying out flash firing for 30-120S to prepare the high-dielectric high-breakdown strontium titanate ceramic. In view of this, the embodiment of the present invention performs the sintering treatment of the strontium titanate ceramic by using the high temperature preheating for a short time and the joule heat under the action of the electric field, so that the sintering time is significantly shortened, the energy and time saving in the preparation process is realized, the grain growth of the ceramic is suppressed while the high densification is maintained, and the dielectric and breakdown characteristics of the strontium titanate ceramic are improved. In addition, the preparation method provided by the embodiment of the invention has the advantages of simple equipment, high production efficiency, energy conservation and environmental protection, and can be widely applied to industrial production of ceramic materials.
The performance test of the strontium titanate ceramic prepared by the embodiment of the invention comprises the following steps: the material has a compact microstructure, no obvious air holes exist, the relative density reaches 97 percent, and the average grain size is 1.77 mu m; has good dielectric properties, a dielectric constant epsilon =380 at 1kHz, a dielectric loss tan delta =0.008, and the dielectric properties show excellent temperature and frequency stability; has more excellent breakdown strength and energy storage density, wherein the breakdown strength is 370kV/cm, and the energy storage density is 2.21J/cm 3 。
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below. It is obvious that the drawings in the following description are some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a graph of voltage intensity and current density over time for the preparation of strontium titanate ceramics in accordance with an embodiment of the present invention;
FIG. 2 is a graph of power loss over time for the preparation of strontium titanate ceramics in accordance with an embodiment of the present invention;
FIG. 3 is an SEM image of a strontium titanate ceramic made by an example of the present invention;
FIG. 4 is a graph of grain size distribution of a strontium titanate ceramic prepared in accordance with an embodiment of the present invention;
FIG. 5 is a graph of dielectric properties of strontium titanate ceramics prepared according to examples of the present invention as a function of frequency;
FIG. 6 is a graph of dielectric properties of strontium titanate ceramics prepared according to an embodiment of the present invention as a function of temperature;
FIG. 7 shows P-E lops of strontium titanate ceramics prepared by the example of the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all 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, in the following description of the embodiments of the present invention, the ball mill for performing ball milling is a QM-3SP2 planetary ball mill manufactured by nanda instruments ltd of Nanjing; the drying oven is a 101-AB electrothermal blowing drying oven produced by Tianjin Tester instruments Co.Ltd; the cold isostatic press is an LDJ100/320-300 type press produced by Chuanxi machine, inc.; the flash Power supply is a direct current Power supply which is produced by Magna-Power company of America and has the model number of SL1250-1.2/UI, the voltage is adjustable within the range of 0-1250V, and the current is adjustable within the range of 0-1.2A.
The preparation method of the high-dielectric high-breakdown strontium titanate ceramic provided by the embodiment of the invention comprises the steps of S101 to S103.
S101: preparing a strontium titanate ceramic blank;
s102: heating the strontium titanate ceramic blank to 1000-1150 ℃, and preserving heat for 30min at the temperature of 1000-1150 ℃;
s103: applying a constant-voltage electric field with the strength of 250V/cm to two ends of the strontium titanate ceramic blank after heat preservation until flash burning occurs, and then controlling the current density to be increased to 10-30 mA/mm 2 And continuously carrying out flash firing, and ending the flash firing after 30-120S to obtain the high-dielectric high-breakdown strontium titanate ceramic.
The preparation method of the high-dielectric high-breakdown strontium titanate ceramic provided by the embodiment of the invention comprises the steps of heating a strontium titanate ceramic blank to 1000-1150 ℃, carrying out heat preservation treatment for 30min, carrying out flash firing by applying a constant voltage electric field of 250V/cm, and controlling the current density to be increased to 10-30 mA/mm after the flash firing occurs 2 And continuously carrying out flash firing for 30-120S to prepare the high-dielectric high-breakdown strontium titanate ceramic. In view of this, the embodiment of the invention carries out flash sintering by controlling the process parameters such as voltage, current density and the like after short-time high-temperature preheating, so that on the first hand, the sintering temperature for preparing the strontium titanate ceramic is reduced to 1000-1150 ℃ from 1350-1500 ℃, and the whole sintering time is less than or equal to 2min, thereby obviously shortening the sintering time while reducing the sintering temperature. Simultaneously, the flash sintering is a sintering mode of 'from inside to outside' with the help of joule heat under the action of an electric field, and can avoid excessive loss of heat compared with the traditional 'from outside to inside' heat radiation sintering mode, so that the heating efficiency is higher. According to the second aspect, flash sintering is carried out after short-time high-temperature preheating, and process parameters such as voltage, current density and the like are effectively controlled in the flash sintering, so that the grain growth of the strontium titanate ceramic can be inhibited, the microstructure of the strontium titanate ceramic can be improved, the dielectric ceramic with high densification degree and fine grains is prepared, and the dielectric property and the impact of the strontium titanate ceramic are realizedFurther improvement in the puncture strength. In the third aspect, the preparation method provided by the embodiment of the invention only needs to use a traditional tube furnace or muffle furnace for flash firing sintering, does not need large or complex professional equipment, has the advantage of simple process equipment, saves energy and time in the whole preparation process, has the advantages of high production efficiency, energy saving and environmental protection, and can be widely applied to industrial production of ceramic materials.
It should be noted that the strontium titanate ceramic body prepared in the embodiment of the present invention is preferably dog-bone shaped, and in the embodiment of the present invention, holes are preferably drilled at two ends of the prepared dog-bone shaped strontium titanate ceramic body, the dog-bone shaped strontium titanate ceramic body is respectively suspended on the parallel platinum wires through the holes at the two ends, and after the other end of the platinum wire is connected with a power supply, the dog-bone shaped strontium titanate ceramic body and the platinum wire are integrally placed in a conventional tube furnace or muffle furnace for flash sintering.
In the present invention, the results of examining the change of voltage intensity and current density with time in the firing and sintering of the dog-bone type strontium titanate ceramic green body are shown in fig. 1 to 2. Wherein, FIG. 1 is a graph of voltage intensity and current density with time in the preparation of strontium titanate ceramics according to an embodiment of the present invention; FIG. 2 is a graph of power loss over time for the preparation of strontium titanate ceramics according to an embodiment of the present invention.
As can be seen from FIGS. 1 and 2, after a constant voltage electric field of 250V/cm is applied, the dog-bone type strontium titanate ceramic body of the embodiment of the invention is subjected to flash-firing phenomenon quickly, and then the current density is controlled to be increased rapidly to 10-30 mA/mm 2 And meanwhile, the resistance of the sample is changed to a certain steady state range, and an obvious power loss peak is generated at the flash burning occurrence point.
In an embodiment of the present invention, the step of preparing the strontium titanate ceramic body preferably includes:
preparing strontium titanate ceramic powder by taking strontium carbonate and titanium dioxide as raw materials;
and sequentially carrying out secondary ball milling, secondary drying, sieving and pressing on the strontium titanate ceramic powder to obtain a strontium titanate ceramic green body.
It should be noted that the specific sources of the strontium carbonate and titanium dioxide are not specifically described in the embodiments of the present invention, so as to obtain strontium titanate meeting the chemical composition requirements.
In the embodiment of the present invention, the preparing a strontium titanate ceramic body preferably further comprises:
and carrying out cold isostatic pressing treatment on the strontium titanate ceramic blank, wherein the pressure of the cold isostatic pressing is controlled to be 200Mpa, and the pressure maintaining time is 3min.
In the embodiment of the present invention, the preparation of the strontium titanate ceramic powder using strontium carbonate and titanium dioxide as raw materials preferably includes:
weighing strontium carbonate and titanium dioxide raw materials according to the stoichiometric ratio of strontium titanate, and then mixing and ball-milling the strontium carbonate and titanium dioxide raw materials, zirconia ball stone and deionized water according to the mass ratio of 1;
drying the mixed raw materials subjected to ball milling at the temperature of 80 ℃, and then calcining for 2 hours at the temperature of 1200 ℃ to obtain the strontium titanate ceramic powder.
It should be noted that in the embodiment of the present invention, when raw materials of strontium carbonate and titanium dioxide are weighed, strontium carbonate and titanium dioxide in equal amounts are specifically taken, and a proper amount of ball milling aid is further added to mix after the raw materials of strontium carbonate and titanium dioxide are weighed, wherein specific components, sources, and amounts of the ball milling aid are not particularly limited, so as to improve ball milling quality and ball milling efficiency of strontium carbonate and titanium dioxide.
In the embodiment of the invention, the time for performing secondary ball milling on the strontium titanate ceramic powder is preferably 8-12 h; the temperature of the secondary drying is preferably 80 ℃.
In the embodiment of the present invention, the standard mesh number of the strontium titanate ceramic powder sieved is preferably 120 to 200 meshes.
In the embodiment of the invention, the heating rate of the strontium titanate ceramic body is preferably 10 ℃/min.
In the embodiment of the invention, the control current density is increased to 10-30 mA/mm 2 Preferably within 1S, to generate electricityThe compressive strength is converted into a certain stable state range along with the resistance of the strontium titanate ceramic powder, and a relatively obvious power loss peak is generated at a flash burning generation point.
In the embodiment of the invention, the breakdown strength of the high-dielectric high-breakdown strontium titanate ceramic is preferably 370kV/cm; the energy storage density is preferably 2.21J/cm 3 。
In the embodiment of the invention, the dielectric constant of the high-dielectric high-breakdown strontium titanate ceramic at 1kHz is preferably 380, and the dielectric loss is preferably 0.008.
Based on the above description, the preparation method of the high-dielectric high-breakdown strontium titanate ceramic provided by the embodiment of the present invention preferably includes the following steps:
s101: weighing strontium carbonate and titanium dioxide as raw materials according to the stoichiometric ratio of strontium titanate, then mixing and ball-milling the raw materials, zirconia ball stone and deionized water according to the mass ratio of 1.
S102: performing secondary ball milling on the strontium titanate ceramic powder obtained by calcining in the step S101, zirconia ball stone and deionized water according to a mass ratio of 1; sieving the dry powder by a 120-200 sample sieve to obtain fine and uniform strontium titanate ceramic powder; weighing a proper amount of strontium titanate ceramic powder, adding the strontium titanate ceramic powder into a mold, and pressing to obtain a dog-bone strontium titanate ceramic blank; and carrying out cold isostatic pressing treatment on the dog-bone type strontium titanate ceramic blank under the condition that the pressure is 200Mpa, and keeping the pressure for 3min.
S103: after drilling holes at two ends of the dog-bone type strontium titanate ceramic blank, hanging the dog-bone type strontium titanate ceramic blank on a parallel platinum wire through the holes at the two ends, connecting the other end of the parallel platinum wire with a power supply, and finally placing the whole body in a tubular furnace;
s104: quickly heating the tube furnace to 1000-1150 ℃ at the speed of 10 ℃/min, preserving the heat for 30min at the temperature of 1000-1150 ℃, and then applying a constant electric field with the voltage intensity of 250V/cm until flash burning occursLike, the control current is rapidly increased to 10-30 mA/mm 2 And after maintaining the flash burning state for 30-120S, cutting off the power supply, and finishing the flash burning to obtain the high-breakdown high-dielectric strontium titanate ceramic.
The technical solution of the present invention will be further elaborated with reference to the following specific examples.
Example 1
The preparation method of the high dielectric high breakdown strontium titanate ceramic provided in embodiment 1 includes the following steps:
s101: weighing strontium carbonate and titanium dioxide as raw materials according to the stoichiometric ratio of strontium titanate, and then sending the raw materials, zirconia ball stone and deionized water into a ball mill according to the mass ratio of 1; and (3) placing the mixed raw material obtained by ball milling in an oven, drying at the temperature of 80 ℃, and then placing in a muffle furnace at the temperature of 1200 ℃ for calcining for 2h to obtain the strontium titanate ceramic powder.
S102: feeding the strontium titanate ceramic powder obtained by calcining in the step S101, zirconia ball stone and deionized water into a ball mill according to a mass ratio of 1; sieving the dry powder by a sample separation sieve of 200 to obtain fine and uniform strontium titanate ceramic powder; weighing a proper amount of strontium titanate ceramic powder, adding the strontium titanate ceramic powder into a mold, and pressing to obtain a dog-bone strontium titanate ceramic blank; and carrying out cold isostatic pressing treatment on the dog-bone type strontium titanate ceramic blank under the condition that the pressure is 200Mpa, and keeping the pressure for 3min, wherein the size of the measurement part of the dog-bone type strontium titanate ceramic blank is 20mm multiplied by 3mm multiplied by 2.26mm.
S103: after drilling holes at two ends of the dog-bone type strontium titanate ceramic blank, hanging the dog-bone type strontium titanate ceramic blank on parallel platinum wires through the holes at the two ends, connecting the other ends of the parallel platinum wires with a power supply, and finally placing the whole body in a tubular furnace;
s104: rapidly heating the tube furnace to 1150 deg.C at 10 deg.C/min, maintaining the temperature at 1150 deg.C for 30min, applying a constant electric field with a voltage of 250V/cm until flash-off occurs, and controlling the current to rapidly increase to 10mA/mm 2 Maintaining the flash-burning state 120S after-cuttingAnd (5) cutting off a power supply, and finishing flash firing to obtain the high-breakdown high-dielectric strontium titanate ceramic.
Example 2
The preparation method of the high dielectric high breakdown strontium titanate ceramic provided in embodiment 2 includes the following steps:
s101: weighing strontium carbonate and titanium dioxide as raw materials according to the stoichiometric ratio of strontium titanate, and then sending the raw materials, zirconia ball stone and deionized water into a ball mill according to the mass ratio of 1; and (3) placing the mixed raw material obtained by ball milling in an oven, drying at the temperature of 80 ℃, and then placing in a muffle furnace at the temperature of 1200 ℃ for calcining for 2 hours to obtain the strontium titanate ceramic powder.
S102: feeding the strontium titanate ceramic powder obtained by calcining in the step S101, zirconia ball stone and deionized water into a ball mill according to the mass ratio of 1; sieving the dry powder by a 120-mesh sample sieve to obtain fine and uniform strontium titanate ceramic powder; weighing a proper amount of strontium titanate ceramic powder, adding the strontium titanate ceramic powder into a mold, and pressing to obtain a dog-bone strontium titanate ceramic blank; and carrying out cold isostatic pressing treatment on the dog-bone-shaped strontium titanate ceramic blank under the condition that the pressure is 200Mpa, and keeping the pressure for 3min, wherein the size of the measurement part of the dog-bone-shaped strontium titanate ceramic blank is 20mm multiplied by 3mm multiplied by 2.26mm.
S103: after drilling holes at two ends of the dog-bone type strontium titanate ceramic blank, hanging the dog-bone type strontium titanate ceramic blank on a parallel platinum wire through the holes at the two ends, connecting the other end of the parallel platinum wire with a power supply, and finally placing the whole body in a tubular furnace;
s104: rapidly heating the tube furnace to 1050 deg.C at 10 deg.C/min, maintaining at 1050 deg.C for 30min, applying a constant electric field with a voltage of 250V/cm until flash-off occurs, and controlling the current to rapidly increase to 20mA/mm 2 And after maintaining the flash burning state for 60 seconds, cutting off a power supply, and finishing the flash burning to obtain the high-breakdown high-dielectric strontium titanate ceramic.
Example 3
The preparation method of the high dielectric high breakdown strontium titanate ceramic provided in this embodiment 2 includes the following steps:
s101: weighing strontium carbonate and titanium dioxide as raw materials according to the stoichiometric ratio of strontium titanate, and then sending the raw materials, zirconia ball stone and deionized water into a ball mill for mixing and ball milling for 12 hours according to the mass ratio of 1; and (3) placing the mixed raw material obtained by ball milling in an oven, drying at the temperature of 80 ℃, and then placing in a muffle furnace at the temperature of 1200 ℃ for calcining for 2 hours to obtain the strontium titanate ceramic powder.
S102: feeding the strontium titanate ceramic powder obtained by calcining in the step S101, zirconia ball stone and deionized water into a ball mill according to the mass ratio of 1; sieving the dry powder by adopting a 120 sample sieve to obtain fine and uniform strontium titanate ceramic powder; weighing a proper amount of strontium titanate ceramic powder, adding the strontium titanate ceramic powder into a mold, and pressing to obtain a dog-bone strontium titanate ceramic blank; and carrying out cold isostatic pressing treatment on the dog-bone type strontium titanate ceramic blank under the condition that the pressure is 200Mpa, and keeping the pressure for 3min, wherein the size of the measurement part of the dog-bone type strontium titanate ceramic blank is 20mm multiplied by 3mm multiplied by 2.26mm.
S103: after drilling holes at two ends of the dog-bone type strontium titanate ceramic blank, hanging the dog-bone type strontium titanate ceramic blank on a parallel platinum wire through the holes at the two ends, connecting the other end of the parallel platinum wire with a power supply, and finally placing the whole body in a tubular furnace;
s104: rapidly heating to 1100 deg.C at 10 deg.C/min, maintaining at 1100 deg.C for 30min, applying a constant electric field with a voltage of 250V/cm until flash-off occurs, and controlling current to rapidly increase to 30mA/mm 2 And after the flash burning state is maintained for 30S, the power supply is cut off, and the high-breakdown high-dielectric strontium titanate ceramic is obtained after the flash burning is finished.
The high-breakdown high-dielectric strontium titanate ceramic prepared in example 3 was subjected to performance characterization, and the results thereof are shown in fig. 3 to 7. Wherein, fig. 3 is an SEM image of the strontium titanate ceramic prepared in example 3; FIG. 4 is a grain size distribution diagram of a strontium titanate ceramic prepared in example 3; FIG. 5 is a graph of dielectric properties of strontium titanate ceramics prepared in example 3 as a function of frequency; FIG. 6 is a graph of dielectric properties of strontium titanate ceramics prepared in example 3 as a function of temperature; FIG. 7 is a P-E lops of strontium titanate ceramic prepared in example 3.
As can be seen from fig. 3 to 4, the strontium titanate ceramic prepared in example 3 has a dense microstructure without significant pores, a relative density of 97%, and an average grain size of 1.77 μm, and the grain growth is suppressed compared to the conventional sintering method.
As can be seen from fig. 5 to 6, the strontium titanate ceramic prepared in example 3 has good dielectric properties, a dielectric constant ∈ =380 at 1kHz, a dielectric loss tan δ =0.008, and excellent temperature and frequency stability of the dielectric properties.
As can be seen from FIG. 7, the P-Eloops of the strontium titanate ceramics prepared in example 3 shows a linear increasing trend along with the increasing of the electric field, the breakdown strength and the polarization strength are increased continuously, and the breakdown strength and the energy storage density of the strontium titanate ceramics prepared in the examples of the present invention are as high as 370kV/cm and 2.21J/cm respectively 3 While the breakdown and energy storage densities reported in the literature are 210kV/cm and 0.7J/cm 3 . Therefore, the preparation method provided by the embodiment of the invention can obviously improve the breakdown strength and the energy storage density of the strontium titanate ceramic, wherein the breakdown strength of the strontium titanate ceramic is improved by 76.19% on the same scale, and the energy storage density is improved by 215.71% on the same scale.
Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations. The embodiments in the present specification are described in a progressive manner, and the same or similar parts among the embodiments may be referred to each other, and each embodiment is described with emphasis on the difference from the other embodiments.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure.
Claims (10)
1. A preparation method of high dielectric high breakdown strontium titanate ceramics is characterized by comprising the following steps:
preparing a strontium titanate ceramic blank;
heating the strontium titanate ceramic blank to 1000-1150 ℃, and preserving heat for 30min at the temperature of 1000-1150 ℃;
applying a constant-voltage electric field with the strength of 250V/cm to two ends of the strontium titanate ceramic blank after heat preservation until flash burning occurs, and then controlling the current density to be increased to 10-30 mA/mm 2 And continuously carrying out flash firing, and ending the flash firing after 30-120S to obtain the high-dielectric high-breakdown strontium titanate ceramic.
2. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic of claim 1, wherein the preparing the strontium titanate ceramic body comprises:
strontium carbonate and titanium dioxide are used as raw materials to prepare strontium titanate ceramic powder;
and sequentially carrying out secondary ball milling, secondary drying, sieving and pressing on the strontium titanate ceramic powder to obtain a strontium titanate ceramic green body.
3. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic of claim 2, wherein the preparing the strontium titanate ceramic body further comprises:
and carrying out cold isostatic pressing treatment on the strontium titanate ceramic blank, wherein the pressure of the cold isostatic pressing is controlled to be 200Mpa, and the pressure maintaining time is 3min.
4. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic according to claim 3, wherein the step of preparing the strontium titanate ceramic powder by using strontium carbonate and titanium dioxide as raw materials comprises the following steps:
weighing raw materials of strontium carbonate and titanium dioxide according to the stoichiometric ratio of strontium titanate, and then mixing and ball-milling the raw materials of strontium carbonate and titanium dioxide, zirconia ball stone and deionized water according to the mass ratio of 1;
drying the mixed raw materials subjected to ball milling at the temperature of 80 ℃, and then calcining for 2 hours at the temperature of 1200 ℃ to obtain the strontium titanate ceramic powder.
5. The preparation method of the high-dielectric high-breakdown strontium titanate ceramic according to claim 4, wherein the time for performing secondary ball milling on the strontium titanate ceramic powder is 8-12 h; the temperature for the secondary drying was 80 ℃.
6. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic of claim 5, wherein the standard mesh number for sieving the strontium titanate ceramic powder is 120-200 meshes.
7. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic of claim 1, wherein the heating rate of the strontium titanate ceramic body is 10 ℃/min.
8. The method for preparing high dielectric high breakdown strontium titanate ceramic of claim 7, wherein the control current density is increased to 10-30 mA/mm 2 This was completed in 1S.
9. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic according to any one of claims 1 to 8, wherein the breakdown strength of the high-dielectric high-breakdown strontium titanate ceramic is 370kV/cm; the energy storage density is 2.21J/cm 3 。
10. The method for preparing the high-dielectric high-breakdown strontium titanate ceramic according to any one of claims 1 to 8, wherein the high-dielectric high-breakdown strontium titanate ceramic has a dielectric constant of 380 at 1kHz and a dielectric loss of 0.008.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210233072.5A CN115304369B (en) | 2022-03-09 | 2022-03-09 | Preparation method of high-dielectric high-breakdown strontium titanate ceramic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210233072.5A CN115304369B (en) | 2022-03-09 | 2022-03-09 | Preparation method of high-dielectric high-breakdown strontium titanate ceramic |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115304369A true CN115304369A (en) | 2022-11-08 |
| CN115304369B CN115304369B (en) | 2023-08-22 |
Family
ID=83854607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210233072.5A Active CN115304369B (en) | 2022-03-09 | 2022-03-09 | Preparation method of high-dielectric high-breakdown strontium titanate ceramic |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115304369B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103708817A (en) * | 2013-12-19 | 2014-04-09 | 桂林电子科技大学 | High pressure-resistance leadless high-temperature ferroelectric ceramic and preparation method thereof |
| US20140306381A1 (en) * | 2011-07-29 | 2014-10-16 | Rishi Raj | Methods of flash sintering |
| CN109081691A (en) * | 2018-09-13 | 2018-12-25 | 长安大学 | A kind of tubular ceramic preparation method |
| CN111981847A (en) * | 2020-07-24 | 2020-11-24 | 北京科技大学 | Pressure-assisted induction heating vacuum atmosphere flash sintering device |
| CN112279639A (en) * | 2020-11-04 | 2021-01-29 | 西南科技大学 | Preparation method of strontium titanate energy storage dielectric ceramic material with high breakdown and high energy storage density |
-
2022
- 2022-03-09 CN CN202210233072.5A patent/CN115304369B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140306381A1 (en) * | 2011-07-29 | 2014-10-16 | Rishi Raj | Methods of flash sintering |
| CN103708817A (en) * | 2013-12-19 | 2014-04-09 | 桂林电子科技大学 | High pressure-resistance leadless high-temperature ferroelectric ceramic and preparation method thereof |
| CN109081691A (en) * | 2018-09-13 | 2018-12-25 | 长安大学 | A kind of tubular ceramic preparation method |
| CN111981847A (en) * | 2020-07-24 | 2020-11-24 | 北京科技大学 | Pressure-assisted induction heating vacuum atmosphere flash sintering device |
| CN112279639A (en) * | 2020-11-04 | 2021-01-29 | 西南科技大学 | Preparation method of strontium titanate energy storage dielectric ceramic material with high breakdown and high energy storage density |
Non-Patent Citations (1)
| Title |
|---|
| TAO OUYANG ET AL.: "Influence of current density on microstructure and dielectric properties during the flash sintering of strontium titanate ceramics" * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115304369B (en) | 2023-08-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106927804B (en) | A kind of microwave-medium ceramics temperature frequency characteristic adjusting control agent and its LTCC material | |
| CN106587987B (en) | The preparation method of C0G microwave dielectric material and preparation method and ceramic material | |
| CN102260044B (en) | Energy storage niobate microcrystalline glass dielectric material and preparation method thereof | |
| CN110204335B (en) | Ceramic material with high energy storage density and efficiency and preparation method thereof | |
| CN109133915A (en) | A kind of high energy storage barium phthalate base dielectric material and preparation method thereof | |
| CA1193835A (en) | Method of manufacturing a dielectric | |
| CN108863348A (en) | A kind of dielectric ceramic material and preparation method thereof of ultra-wide temperature stability | |
| CN111704463B (en) | Dielectric ceramic material and preparation method thereof | |
| CN111470863A (en) | Strontium-doped zirconium titanium lead stannate lanthanum-lead relaxivity antiferroelectric thick film ceramic and preparation method and application thereof | |
| CN114163231B (en) | Lead-free pulse dielectric medium energy storage composite ceramic material and preparation method and application thereof | |
| CN115304369B (en) | Preparation method of high-dielectric high-breakdown strontium titanate ceramic | |
| CN112521145B (en) | Barium strontium titanate-based ceramic with high energy storage density and power density and preparation method thereof | |
| CN110240409A (en) | Lead bariun niobate sodium base glass ceramic material of high energy storage density and preparation method thereof | |
| Fang et al. | An investigation demonstrating the feasibility of microwave sintering of base-metal-electrode multilayer capacitors | |
| CN112919902A (en) | Preparation method of electric field assisted low-temperature rapid sintering fine-grain barium titanate capacitor ceramic | |
| CN109320236B (en) | Composite material with high energy storage density and charge-discharge performance and preparation method thereof | |
| CN101357848A (en) | Electronic ceramic composite preparation method by laser sintering | |
| CN109456055A (en) | A kind of high breakdown high polarization bismuth-sodium titanate ceramic material, preparation method and application | |
| CN105198409A (en) | Preparation method of barium-strontium-titanate-based glass composite ceramic with high energy storage density | |
| CN114907102A (en) | Ceramic material and room-temperature ultrafast reactive sintering method thereof | |
| CN105742056A (en) | High-energy borophosphate microcrystalline glass dielectric material and preparation method thereof | |
| CN105622084A (en) | Preparation method of zinc oxide pressure-sensitive resistor | |
| CN114478006A (en) | KNNS-BNZ + CuO piezoceramic material and preparation method and application thereof | |
| CN108892506A (en) | A kind of method preparing potassium sodium niobate piezoelectric ceramics and potassium sodium niobate piezoelectric ceramics | |
| JP2022529859A (en) | Dope perovskite-type barium titanate material, its manufacturing method, and its uses |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |