CN113816418A - Defect-free barium titanate powder and preparation method thereof - Google Patents
Defect-free barium titanate powder and preparation method thereof Download PDFInfo
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- 239000000843 powder Substances 0.000 title claims abstract description 71
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 229910002113 barium titanate Inorganic materials 0.000 title claims abstract description 68
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 239000000243 solution Substances 0.000 claims abstract description 119
- 229910052788 barium Inorganic materials 0.000 claims abstract description 35
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims abstract description 35
- 238000006243 chemical reaction Methods 0.000 claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 32
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000001816 cooling Methods 0.000 claims abstract description 26
- XBYNNYGGLWJASC-UHFFFAOYSA-N barium titanium Chemical compound [Ti].[Ba] XBYNNYGGLWJASC-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000012670 alkaline solution Substances 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 19
- 238000001035 drying Methods 0.000 claims abstract description 18
- 239000012535 impurity Substances 0.000 claims abstract description 15
- 238000002156 mixing Methods 0.000 claims abstract description 13
- 239000011261 inert gas Substances 0.000 claims abstract description 10
- 238000005245 sintering Methods 0.000 claims abstract description 9
- 230000001502 supplementing effect Effects 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 24
- 239000010936 titanium Substances 0.000 claims description 18
- 239000012295 chemical reaction liquid Substances 0.000 claims description 17
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 238000009826 distribution Methods 0.000 claims description 15
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 15
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 12
- 230000007062 hydrolysis Effects 0.000 claims description 12
- 238000006460 hydrolysis reaction Methods 0.000 claims description 12
- 239000000047 product Substances 0.000 claims description 12
- 229910052719 titanium Inorganic materials 0.000 claims description 12
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 11
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 9
- 238000001914 filtration Methods 0.000 claims description 8
- 239000002585 base Substances 0.000 claims description 7
- 239000013078 crystal Substances 0.000 claims description 6
- 239000011164 primary particle Substances 0.000 claims description 6
- 229910010270 TiOCl2 Inorganic materials 0.000 claims description 5
- 239000000084 colloidal system Substances 0.000 claims description 5
- 239000003960 organic solvent Substances 0.000 claims description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 4
- 238000001556 precipitation Methods 0.000 claims description 4
- 238000004321 preservation Methods 0.000 claims description 4
- 125000001453 quaternary ammonium group Chemical group 0.000 claims description 4
- 239000006228 supernatant Substances 0.000 claims description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 3
- OEYIOHPDSNJKLS-UHFFFAOYSA-N choline Chemical compound C[N+](C)(C)CCO OEYIOHPDSNJKLS-UHFFFAOYSA-N 0.000 claims description 3
- 229960001231 choline Drugs 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims 1
- 239000002994 raw material Substances 0.000 abstract description 7
- 239000000919 ceramic Substances 0.000 abstract description 2
- 238000009827 uniform distribution Methods 0.000 abstract 1
- 238000003917 TEM image Methods 0.000 description 17
- 239000012528 membrane Substances 0.000 description 10
- 238000003756 stirring Methods 0.000 description 8
- 239000011347 resin Substances 0.000 description 7
- 125000000129 anionic group Chemical group 0.000 description 6
- 230000007547 defect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 238000003786 synthesis reaction Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000001027 hydrothermal synthesis Methods 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000004408 titanium dioxide Substances 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 229910003074 TiCl4 Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- ZUDYPQRUOYEARG-UHFFFAOYSA-L barium(2+);dihydroxide;octahydrate Chemical compound O.O.O.O.O.O.O.O.[OH-].[OH-].[Ba+2] ZUDYPQRUOYEARG-UHFFFAOYSA-L 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012510 hollow fiber Substances 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 2
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 2
- OBMBUODDCOAJQP-UHFFFAOYSA-N 2-chloro-4-phenylquinoline Chemical compound C=12C=CC=CC2=NC(Cl)=CC=1C1=CC=CC=C1 OBMBUODDCOAJQP-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 1
- 229910001863 barium hydroxide Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006298 dechlorination reaction Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000007530 organic bases Chemical class 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- 238000004627 transmission electron microscopy Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/003—Titanates
- C01G23/006—Alkaline earth titanates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/30—Three-dimensional structures
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
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- Life Sciences & Earth Sciences (AREA)
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- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention relates to the technical field of dielectric ceramic raw materials, in particular to defect-free barium titanate powder and a preparation method thereof, wherein the preparation method comprises the following steps: A) TiCl with a concentration of 0.1-1.0 mol/L4Hydrolyzing the solution to obtain TiO2A colloidal solution; B) removing impurities and concentrating to obtain a colloidal solution with the mass content of 8-28%; C) heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, adding a barium source to dissolve, mixing with the colloidal solution obtained in the step B), reacting at 100-110 ℃, detecting the barium-titanium molar ratio in a reaction solution during the reaction, supplementing raw materials to ensure that the barium-titanium molar ratio does not exceed 0.0010, and drying a product after the reaction; D) sintering at 400-1100 ℃, and crushing to obtain defect-free barium titanate powder with small particle size and uniform distribution.
Description
Technical Field
The invention relates to the technical field of dielectric ceramic raw materials, in particular to defect-free barium titanate powder and a preparation method thereof.
Background
With the rapid development of science and technology, the electronic science and technology age has come, and information products gradually enter the lives of everyone and occupy a great deal of time of the everyone. The MLCC multilayer capacitor is an indispensable element in the existing electronic products, and barium titanate powder is used as a raw material of MLCC, and has come to be an important development opportunity along with the reasons of increasing demand of electronic products, miniaturization of products and the like.
At present, the preparation process of the high-end barium titanate powder is mainly a hydrothermal method, and the hydrothermal method is to use TiCl4Or TiOCl2As a titanium source, hydrated titanium dioxide (or called titanium hydroxide emulsion) is formed by adjusting the pH with alkali or the like, and then barium titanate powder is synthesized with barium hydroxide in a high-temperature and high-pressure environment. For example, in chinese patent CN105849049B, titanium tetrachloride is reacted with alkali to prepare hydrated titanium dioxide, and then hydrothermal synthesis is performed in a high-temperature high-pressure reaction kettle to prepare barium titanate. Although the process can be used for preparing barium titanate powder with high crystallinity, the hydrated titanium dioxide contains a certain content of hydroxyl in the synthesis process, the hydroxyl falls off to form pits in the drying process after synthesis, and excessive barium needs to be cleaned by an acid detergent in the later period after hydrothermal synthesis, so that the pits are also generated, and the performance of components is influenced.
Although the method of synthesizing barium titanate powder by normal pressure and high temperature method is used in CN1935635B, TiOCl is used2The titanium sol is prepared by ammonia water and tetraisopropyl titanate, and the generation of powder surface pits is still difficult to avoid.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a defect-free barium titanate powder and a preparation method thereof.
The invention provides a preparation method of defect-free barium titanate powder, which comprises the following steps:
A) TiCl with a concentration of 0.1-1.0 mol/L4Solutions or TiOCl2Hydrolyzing the solution to obtain TiO2A colloidal solution;
B) subjecting the TiO to a reaction2Removing impurities from the colloidal solution and concentrating to obtain a colloidal solution with the mass content of 8-28%;
C) heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, putting a barium source into the alkaline solution for dissolving, mixing the barium source with the colloidal solution obtained in the step B), and reacting at 100-110 ℃, wherein in the reaction process, the barium-titanium molar ratio in the reaction liquid is detected, and after the barium-titanium molar ratio changes and exceeds 0.0010, the colloidal solution or the barium source obtained in the step B) is supplemented, so that the barium-titanium molar ratio in the reaction liquid does not change and exceeds 0.0010, and after the reaction is finished, the obtained product is dried;
D) sintering at 400-1100 ℃, and crushing to obtain the defect-free barium titanate powder.
Preferably, in the step A), the hydrolysis temperature is 90-105 ℃, and the hydrolysis is carried out under normal pressure.
Preferably, in step A), the TiO is2The specific surface area of the colloidal particles in the colloidal solution is 50-200 m2(ii)/g, the primary particle size is 8-30 nm;
the TiO is2The crystal form distribution of the colloidal particles in the colloidal solution comprises:
more than or equal to 50 wt% of brookite, less than or equal to 10 wt% of rutile and the balance of anatase.
Preferably, in the step B), the chloride ion concentration of the colloid solution after impurity removal is 100-10000 ppm;
the pH value of the colloid solution after impurity removal is 1.5-4.5.
Preferably, step C) comprises:
heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, adding a barium source to dissolve, mixing with the colloidal solution obtained in the step B), reacting at 100-110 ℃ for more than or equal to 60min, detecting the barium-titanium molar ratio in the reaction liquid, supplementing the colloidal solution or barium source obtained in the step B) to ensure that the barium-titanium molar ratio in the reaction liquid does not change more than 0.0010, continuing to react for 30-60 min, and drying the obtained product.
Preferably, the alkaline solution comprises a sodium hydroxide solution, a lithium hydroxide solution, a potassium hydroxide solution, a quaternary ammonium base solution or a choline base solution;
the heat preservation time is more than or equal to 10 min.
Preferably, the molar ratio of barium in the barium source to titanium in the colloidal solution obtained in step B) is 0.9-1.1: 1.
preferably, the method further comprises the following steps before the reaction at 100-110 ℃:
heating to 100-110 ℃ at a speed of more than or equal to 2 ℃/min.
Preferably, after the continuous reaction is finished, the method further comprises:
cooling to room temperature at a speed of more than or equal to 2 ℃/min;
after the cooling, the method further comprises the following steps:
standing for precipitation, pouring out supernatant, washing with alcohol solution or other organic solvent, and filtering;
the drying temperature is 150-300 ℃.
The invention also provides defect-free barium titanate powder prepared by the preparation method.
The invention provides a preparation method of defect-free barium titanate powder, which comprises the following steps: A) TiCl with a concentration of 0.1-1.0 mol/L4Hydrolyzing the solution to obtain TiO2A colloidal solution; B) subjecting the TiO to a reaction2Removing impurities from the colloidal solution and concentrating to obtain a colloidal solution with the mass content of 8-28%; C) heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, putting a barium source into the alkaline solution for dissolving, mixing the barium source with the colloidal solution obtained in the step B), and reacting at 100-110 ℃, wherein in the reaction process, the barium-titanium molar ratio in the reaction liquid is detected, and after the barium-titanium molar ratio changes and exceeds 0.0010, the colloidal solution or the barium source obtained in the step B) is supplemented, so that the barium-titanium molar ratio in the reaction liquid does not change and exceeds 0.0010, and after the reaction is finished, the obtained product is dried; D) sintering at 400-1100 ℃, and crushing to obtain the defect-free barium titanate powder. The defect-free barium titanate powder prepared by the method has the advantages of square-like shape, good dispersibility, small particle size and uniform particle distribution.
Drawings
FIG. 1 is an SEM photograph of barium titanate powder of example 1 of the present invention;
FIG. 2 is a particle size distribution diagram of barium titanate powder in example 1 of the present invention;
FIG. 3 is a TEM image of barium titanate powder of example 1 of the present invention;
FIG. 4 is an XRD pattern of barium titanate powder of example 1 of the present invention;
FIG. 5 is a TEM image of barium titanate powder of example 2 of the present invention;
FIG. 6 is a TEM image of barium titanate powder of example 3 of the present invention;
FIG. 7 is a TEM image of barium titanate powder of example 4 of the present invention;
FIG. 8 is a TEM image of barium titanate powder of example 5 of the present invention;
FIG. 9 is a TEM image of barium titanate powder of example 6 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood 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.
The invention provides a preparation method of defect-free barium titanate powder, which comprises the following steps:
A) TiCl with a concentration of 0.1-1.0 mol/L4Hydrolyzing the solution to obtain TiO2A colloidal solution;
B) subjecting the TiO to a reaction2Removing impurities from the colloidal solution and concentrating to obtain a colloidal solution with the mass content of 8-28%;
C) heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, putting a barium source into the alkaline solution for dissolving, mixing the barium source with the colloidal solution obtained in the step B), and reacting at 100-110 ℃, wherein in the reaction process, the barium-titanium molar ratio in the reaction liquid is detected, and after the barium-titanium molar ratio changes and exceeds 0.0010, the colloidal solution or the barium source obtained in the step B) is supplemented, so that the barium-titanium molar ratio in the reaction liquid does not change and exceeds 0.0010, and after the reaction is finished, the obtained product is dried;
D) sintering at 400-1100 ℃, and crushing to obtain the defect-free barium titanate powder.
In step A):
in certain embodiments of the invention, step a) comprises:
TiCl with a concentration of 0.1-1.0 mol/L4Solutions or TiOCl2Heating the solution to hydrolysis temperature for hydrolysis to obtain TiO2A colloidal solution.
In certain embodiments of the invention, the TiCl is4The concentration of the solution was 0.4 mol/L. In certain embodiments of the invention, the TiCl is4The solvent of the solution is water.
In certain embodiments of the invention, the rate of temperature increase is greater than or equal to 2 deg.C/min. In certain embodiments, the rate of temperature increase is 2 ℃/min.
In some embodiments of the invention, the temperature of the hydrolysis is 90-105 ℃, and the hydrolysis is carried out under normal pressure. In certain embodiments, the temperature of the hydrolysis is 104 ℃. In some embodiments of the present invention, the hydrolysis time is 60 to 240 min. In certain embodiments, the time for hydrolysis is 60 min.
In certain embodiments of the present invention, after the hydrolysis is completed, the method further comprises: and (6) cooling. In certain embodiments of the invention, the rate of cooling is ≧ 2 ℃/min. In certain embodiments, the rate of cooling is 2 ℃/min. In certain embodiments, the cooled temperature is room temperature.
In certain embodiments of the invention, the TiO is2The specific surface area of the colloidal particles in the colloidal solution is 50-200 m2(ii)/g, the primary particle diameter is 8 to 30 nm.
In certain embodiments of the invention, the TiO is2The crystal form distribution of the colloidal particles in the colloidal solution comprises:
more than or equal to 50 wt% of brookite, less than or equal to 10 wt% of rutile and the balance of anatase.
In certain embodiments, the TiO2The crystal form distribution of the colloidal particles in the colloidal solution comprises:
65.42 wt% brookite, 4.34 wt% rutile and 30.24 wt% anatase.
The invention passes through low-concentration TiCl4Solutions or low concentrations of TiOCl2The solution forced hydrolysis method can obtain superfine TiO with good dispersity and excellent grain size distribution2A colloidal solution.
In step B):
the invention does not particularly limit the sequence of the impurity removal and concentration.
In certain embodiments of the invention, the TiO is paired with an anionic resin2Removing impurities from the colloidal solution.
In certain embodiments of the invention, the anionic resin comprises a PA316 anionic resin.
In certain embodiments of the invention, the anionic resin and the TiO2The dosage ratio of the colloidal solution is 1196-1674 g: 1L of the compound. In certain embodiments, the anionic resin and the TiO are2The dosage ratio of the colloidal solution is 1395 g: 1L of the compound.
In some embodiments of the invention, the concentration of chloride ions in the decontaminated colloidal solution is 100 to 10000 ppm.
In some embodiments of the invention, the pH of the colloid solution after impurity removal is 1.5-4.5. In certain embodiments, the pH of the decontaminated colloidal solution is 4.
In some embodiments of the present invention, the concentration is a membrane concentration, and the concentration membrane used in the membrane concentration may be selected from membrane modules such as tubular membrane, plate membrane or roll membrane. In certain embodiments, the concentration membrane used for the concentration is a hollow fiber membrane.
In certain embodiments of the invention, the mass content of the concentrated colloidal solution is 15.3%.
Concentrated superfine TiO2The colloidal solution is stable and does not precipitate even after being placed for a long time.
In step C):
in certain embodiments of the invention, step C) comprises:
heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, adding a barium source to dissolve, mixing with the colloidal solution obtained in the step B), reacting at 100-110 ℃ for more than or equal to 60min, detecting the barium-titanium molar ratio in the reaction liquid, supplementing the colloidal solution or barium source obtained in the step B) to ensure that the barium-titanium molar ratio in the reaction liquid does not change more than 0.0010, continuing to react for 30-60 min, and drying the obtained product.
In certain embodiments of the invention, the dissolving is stirred dissolving and the mixing is stirred mixing.
In the present invention, the alkaline solution is a catalyst. In certain embodiments of the present invention, the alkaline solution may be an organic alkaline solution or an inorganic alkaline solution. The inorganic alkali solution includes a metal hydroxide solution, and specifically, may be a sodium hydroxide solution, a lithium hydroxide solution, or a potassium hydroxide solution. The organic base solution includes a quaternary ammonium base solution or a choline base solution. In certain embodiments, the quaternary ammonium base solution is a tetramethylammonium hydroxide solution.
In certain embodiments of the invention, the alkaline solution has a pH of 14.
In certain embodiments of the invention, the treatment of the alkaline solution at a pH ≧ 12 is carried out in a reaction vessel.
According to the invention, the alkaline solution with the pH value of more than or equal to 12 is heated to the temperature of more than or equal to 80 ℃, and carbonate in the solution can be effectively removed after heat preservation. In some embodiments of the present invention, the temperature after heating is 80-90 ℃. In certain embodiments, the temperature after heating is 90 ℃. In certain embodiments of the invention, the incubation time is 10min or more.
In certain embodiments of the invention, the inert gas is nitrogen or helium.
The present invention is not particularly limited to the cooling rate ratio, and natural cooling may be used. The temperature after cooling is not particularly limited, and the cooling may be performed to room temperature.
In the invention, the alkaline solution is heated to the temperature of more than or equal to 80 ℃, and the purpose of inert gas protection cooling is to ensure that only a very small amount of CO is stored in the solution2Avoidance of CO2By reaction with barium saltsBa2CO3Impurities.
In some embodiments of the present invention, the molar ratio of barium in the barium source to titanium in the colloidal solution obtained in step B) is 0.9 to 1.1: 1. in certain embodiments, the molar ratio of barium in the barium source to titanium in the colloidal solution obtained in step B) is 1.0050: 1. 0.9905: 1. 0.9980: 1. 1.0030: 1. 1.0080: 1 or 1.0120: 1.
in some embodiments of the present invention, the method further comprises, after mixing with the colloidal solution obtained in step B): heating to 100-110 ℃ at the speed of more than or equal to 2 ℃/min, and reacting at 100-110 ℃ for more than or equal to 60 min.
In some embodiments of the invention, the temperature is raised to 104 ℃ at a rate of 2 ℃/min and then reacted for 60min at 104 ℃.
In certain embodiments of the invention, the time for continuing the reaction is 30 min.
In certain embodiments of the invention, the reaction is carried out under stirring. The stirring method and the rotation speed are not particularly limited in the present invention, and the stirring method and the rotation speed known to those skilled in the art may be used.
In some embodiments of the present invention, after the reaction is finished, the method further comprises:
cooling to room temperature at a speed of more than or equal to 2 ℃/min.
In certain embodiments, the rate of cooling is 2 ℃/min.
In some embodiments of the present invention, after the cooling, further comprising:
standing for precipitation, pouring out supernatant, washing with alcohol solution or other organic solvent, and filtering.
In certain embodiments of the invention, the alcohol solution comprises an ethanol solution or a glycol solution. In certain embodiments, the alcohol solution has a mass concentration of 95%.
The invention further uses alcohol solution to clean, and removes alkaline substances, impurities and the like after reaction, thereby obtaining barium titanate powder with higher purity.
In certain embodiments of the present invention, the mass ratio of the alcohol solution or other organic solvent to the precipitate is 1.5-6: 1. in certain embodiments, the mass ratio of the alcoholic solution or other organic solvent to the precipitate is 5: 1.
in some embodiments of the present invention, the temperature of the drying is 150 to 300 ℃. In certain embodiments, the temperature of the drying is 150 ℃.
The filtering and drying method is not particularly limited, and the filtering and drying method can adopt plate-and-frame filter pressing + drying, centrifugal filtering + drying, flash drying, spraying, cleaning, filtering and drying three-in-one equipment and the like, and in some embodiments, the drying method can be drying.
In step D):
in certain embodiments of the present invention, the temperature of the sintering is 900 ℃.
In some embodiments of the present invention, the sintering time is 1.5 to 2.5 hours. In certain embodiments of the present invention, the sintering time is 2 hours.
In some embodiments of the present invention, after the crushing, further comprising: and (6) sieving. In some embodiments, the particles are sieved through a 100-120 mesh sieve.
The source of the above-mentioned raw materials is not particularly limited, and the raw materials may be generally commercially available.
The invention also provides defect-free barium titanate powder prepared by the preparation method.
The defect-free barium titanate powder provided by the invention is square-like in shape, good in dispersity, small in particle size and narrow in distribution.
In some embodiments of the invention, the defect-free barium titanate powder has a primary particle size of 140 to 160 nm. In the invention, in order to ensure the uniformity of Ba/Ti and particle size between different particles before and after synthesis, the synthesis process is designed as follows: the method comprises the steps of uniformly mixing a titanium source and a barium source at a low temperature, then rapidly heating to 100-110 ℃, and carrying out heat preservation synthesis, so that the problems that the titanium source and the barium source which are firstly added are preferentially nucleated and the Ba/Ti segregation or poor particle size distribution of the materials which are then added due to different solution concentrations in a synthetic solution are solved.
In order to further illustrate the present invention, the defect-free barium titanate powder and the preparation method thereof provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
Example 1
1) 0.4mol/L TiCl is used4Pouring 5L of the solution into a four-mouth flat-bottom flask, heating to 104 ℃ at a heating rate of 2 ℃/min, hydrolyzing at 104 ℃ for 60min, and cooling to room temperature at a rate of 2 ℃/min to obtain TiO2A colloidal solution;
2) pairing the TiO with Mitsubishi chemical PA316 anion resin2Removing impurities from the colloidal solution, the anionic resin and the TiO2The dosage ratio of the colloidal solution is 1395 g: 1L, stopping dechlorination when the pH value of the colloidal solution is 4, wherein the chloride ion concentration of the colloidal solution is 402ppm, and concentrating by using an Asahi chemical conversion hollow fiber membrane to obtain a colloidal solution with the mass content of 15.3%;
3) preparing 2mol/L sodium hydroxide solution (pH value is 14), placing 1.5L sodium hydroxide solution in a reaction kettle, heating to 90 ℃ by an electric heating jacket, preserving heat for 10min, naturally cooling to room temperature under the protection of nitrogen, adding 350g barium hydroxide octahydrate powder, stirring for dissolving, then adding 564.8g colloidal solution prepared in the step 2), stirring and mixing, wherein the molar ratio of barium to titanium in reaction solution is 1.0050: 1, heating to 104 ℃ at the speed of 2 ℃/min, stirring for reacting for 60min, detecting the molar ratio of barium to titanium in the reaction solution to be 1.0064, supplementing 0.7856g of the colloidal solution prepared in the step 2), enabling the molar ratio of barium to titanium in the reaction solution to be 1.0050, continuing stirring for reacting for 30min, cooling to room temperature at the speed of 2 ℃/min, standing for precipitation, pouring out supernatant, cleaning by using 5 times of ethanol solution with the mass concentration of 95%, filtering into powder cakes, and drying at 150 ℃;
4) sintering at 900 deg.C for 2h, crushing, and sieving with 120 mesh sieve to obtain barium titanate powder with primary particle diameter of 156nm and Ba/Ti of 1.0052.
For the TiO obtained in the step 1)2The specific surface area and the crystal form distribution of the colloidal particles in the colloidal solution were measured, and the results are shown in table 1:
TABLE 1TiO2Specific surface area and crystal form distribution of colloidal particles in colloidal solution
The barium titanate powder obtained in example 1 was analyzed by scanning electron microscopy, and the results are shown in fig. 1. FIG. 1 is an SEM photograph of barium titanate powder of example 1 of the present invention. As can be seen from fig. 1, the barium titanate powder prepared in this example has a square-like sample morphology, good dispersibility, and uniform particle distribution.
In this embodiment, 3 to 5 regions of the same sample are photographed, the photographed SEM picture is subjected to particle size dotting, the sizes of the particles obtained by drawing are analyzed in a summary manner, and finally, a particle size distribution diagram is prepared according to the analysis result, as shown in fig. 2. FIG. 2 is a particle size distribution diagram of barium titanate powder in example 1 of the present invention. As can be seen from fig. 2, the particle size of the barium titanate powder prepared in this example is normally distributed, and analysis shows that the standard deviation σ of the plotted particle size is 41.812, the plotted average particle size is 169nm, and the CV value σ/the plotted average particle size is 23.42%, which indicates that the particle size distribution is uniform.
The CV value is obtained by summarizing the particle diameters obtained by plotting each particle in the SEM electron micrograph, and calculating the standard deviation δ of the particle diameter and the average value D of the particle diameter according to the formula CV ═ δ/D × 100%.
The specific surface area of the barium titanate powder obtained in example 1 was measured, and the specific surface area BET of the barium titanate powder prepared in example 1 was 6.7432m2(BET) 147.9 nm. Wherein D (BET) is a primary particle size value converted by using a specific surface area-BET measurement value, and c/a is 1.0099, and the crystallinity is good.
The barium titanate powder obtained in example 1 was analyzed by transmission electron microscopy, and the results are shown in fig. 3. FIG. 3 is a TEM image of barium titanate powder of example 1 of the present invention. As can be seen from fig. 3, the barium titanate powder prepared in this example has no defects on the surface.
XRD analysis was performed on the barium titanate powder obtained in example 1, and the result is shown in fig. 4. FIG. 4 shows an embodiment of the present invention1 XRD pattern of barium titanate powder. As can be seen from FIG. 4, each peak position of the barium titanate powder of example 1 was in accordance with BaTiO No. 83 to 18803The PDF cards are consistent.
Examples 2 to 6
By changing the adding amount of the barium hydroxide octahydrate powder, the barium-titanium molar ratio (target Ba/Ti) in the reaction liquid in the step 3) of the embodiment 1 is changed, the stirring reaction is carried out for 60min, the barium-titanium molar ratio in the reaction liquid is detected to be the process sample Ba/Ti, after the raw materials are supplemented, the barium-titanium molar ratio in the reaction liquid is the finished product Ba/Ti, and the rest steps are carried out according to the steps of the embodiment 1 of the invention, so that the barium titanate powder is prepared. The corresponding parameters and properties are shown in table 2.
TABLE 2 molar ratio of barium to titanium and Properties of barium titanate powders obtained in examples 2 to 6
A TEM image of the barium titanate powder of example 2 is shown in fig. 5. FIG. 5 is a TEM image of barium titanate powder of example 2 of the present invention. As can be seen from fig. 5, the barium titanate powder prepared in this example has no defects on the surface.
A TEM image of the barium titanate powder of example 3 is shown in fig. 6. FIG. 6 is a TEM image of barium titanate powder of example 3 of the present invention. As can be seen from fig. 6, the barium titanate powder prepared in this example has no defects on the surface.
A TEM image of the barium titanate powder of example 4 is shown in fig. 7. FIG. 7 is a TEM image of barium titanate powder of example 4 of the present invention. As can be seen from fig. 7, the barium titanate powder prepared in this example has no defects on the surface.
A TEM image of the barium titanate powder of example 5 is shown in fig. 8. FIG. 8 is a TEM image of barium titanate powder of example 5 of the present invention. As can be seen from fig. 8, the barium titanate powder prepared in this example has no defects on the surface.
A TEM image of the barium titanate powder of example 6 is shown in fig. 9. FIG. 9 is a TEM image of barium titanate powder of example 6 of the present invention. As can be seen from fig. 9, the barium titanate powder prepared in this example has no defects on the surface.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for preparing defect-free barium titanate powder comprises the following steps:
A) TiCl with a concentration of 0.1-1.0 mol/L4Solutions or TiOCl2Hydrolyzing the solution to obtain TiO2A colloidal solution;
B) subjecting the TiO to a reaction2Removing impurities from the colloidal solution and concentrating to obtain a colloidal solution with the mass content of 8-28%;
C) heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, putting a barium source into the alkaline solution for dissolving, mixing the barium source with the colloidal solution obtained in the step B), and reacting at 100-110 ℃, wherein in the reaction process, the barium-titanium molar ratio in the reaction liquid is detected, and after the barium-titanium molar ratio changes and exceeds 0.0010, the colloidal solution or the barium source obtained in the step B) is supplemented, so that the barium-titanium molar ratio in the reaction liquid does not change and exceeds 0.0010, and after the reaction is finished, the obtained product is dried;
D) sintering at 400-1100 ℃, and crushing to obtain the defect-free barium titanate powder.
2. The method according to claim 1, wherein the hydrolysis in step A) is carried out at a temperature of 90 to 105 ℃ under normal pressure.
3. The method according to claim 1, wherein in step A), the TiO is2The specific surface area of the colloidal particles in the colloidal solution is 50-200 m2(ii)/g, the primary particle size is 8-30 nm;
the TiO is2The crystal form distribution of the colloidal particles in the colloidal solution comprises:
more than or equal to 50 wt% of brookite, less than or equal to 10 wt% of rutile and the balance of anatase.
4. The preparation method according to claim 1, wherein in the step B), the concentration of chloride ions in the colloid solution after impurity removal is 100-10000 ppm;
the pH value of the colloid solution after impurity removal is 1.5-4.5.
5. The method of claim 1, wherein step C) comprises:
heating an alkaline solution with the pH value of more than or equal to 12 to the temperature of more than or equal to 80 ℃, preserving heat, cooling under the protection of inert gas, adding a barium source to dissolve, mixing with the colloidal solution obtained in the step B), reacting at 100-110 ℃ for more than or equal to 60min, detecting the barium-titanium molar ratio in the reaction liquid, supplementing the colloidal solution or barium source obtained in the step B) to ensure that the barium-titanium molar ratio in the reaction liquid does not change more than 0.0010, continuing to react for 30-60 min, and drying the obtained product.
6. The production method according to claim 5, wherein the alkali solution includes a sodium hydroxide solution, a lithium hydroxide solution, a potassium hydroxide solution, a quaternary ammonium base solution, or a choline base solution;
the heat preservation time is more than or equal to 10 min.
7. The preparation method according to claim 5, wherein the molar ratio of barium in the barium source to titanium in the colloidal solution obtained in step B) is 0.9-1.1: 1.
8. the preparation method according to claim 5, further comprising, before the reaction at 100-110 ℃:
heating to 100-110 ℃ at a speed of more than or equal to 2 ℃/min.
9. The method according to claim 5, further comprising, after the end of the further reaction:
cooling to room temperature at a speed of more than or equal to 2 ℃/min;
after the cooling, the method further comprises the following steps:
standing for precipitation, pouring out supernatant, washing with alcohol solution or other organic solvent, and filtering;
the drying temperature is 150-300 ℃.
10. The defect-free barium titanate powder prepared by the preparation method of any one of claims 1 to 9.
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| US20050281733A1 (en) * | 2004-06-18 | 2005-12-22 | Ming-Tseh Tsay | Methods of fabricating barium titanate powders |
| CN104446445A (en) * | 2014-11-25 | 2015-03-25 | 江门市科恒实业股份有限公司 | Preparation method of monodisperse nano-powdery barium titanate |
| CN105836794A (en) * | 2016-04-22 | 2016-08-10 | 广东风华高新科技股份有限公司 | Preparation method of barium titanate powder |
| CN113292097A (en) * | 2021-05-26 | 2021-08-24 | 深圳先进电子材料国际创新研究院 | Method for preparing high-tetragonality barium titanate powder |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20050281733A1 (en) * | 2004-06-18 | 2005-12-22 | Ming-Tseh Tsay | Methods of fabricating barium titanate powders |
| CN104446445A (en) * | 2014-11-25 | 2015-03-25 | 江门市科恒实业股份有限公司 | Preparation method of monodisperse nano-powdery barium titanate |
| CN105836794A (en) * | 2016-04-22 | 2016-08-10 | 广东风华高新科技股份有限公司 | Preparation method of barium titanate powder |
| CN113292097A (en) * | 2021-05-26 | 2021-08-24 | 深圳先进电子材料国际创新研究院 | Method for preparing high-tetragonality barium titanate powder |
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