CN117263672A - Method for synthesizing nano barium titanate-based powder in water vapor - Google Patents
Method for synthesizing nano barium titanate-based powder in water vapor Download PDFInfo
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- 239000000843 powder Substances 0.000 title claims abstract description 107
- 229910002113 barium titanate Inorganic materials 0.000 title claims abstract description 106
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 91
- 238000000034 method Methods 0.000 title claims abstract description 49
- 230000002194 synthesizing effect Effects 0.000 title claims abstract description 17
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 title claims abstract 16
- 239000002245 particle Substances 0.000 claims abstract description 40
- -1 polytetrafluoroethylene Polymers 0.000 claims abstract description 34
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims abstract description 34
- 239000004810 polytetrafluoroethylene Substances 0.000 claims abstract description 34
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 30
- 229910001220 stainless steel Inorganic materials 0.000 claims abstract description 26
- 239000010935 stainless steel Substances 0.000 claims abstract description 26
- 230000001954 sterilising effect Effects 0.000 claims abstract description 26
- 238000004659 sterilization and disinfection Methods 0.000 claims abstract description 26
- 238000001035 drying Methods 0.000 claims abstract description 22
- 239000010936 titanium Substances 0.000 claims abstract description 18
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 16
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052788 barium Inorganic materials 0.000 claims abstract description 14
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 14
- 230000035484 reaction time Effects 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 12
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000012153 distilled water Substances 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- 238000003825 pressing Methods 0.000 claims abstract description 9
- 238000005406 washing Methods 0.000 claims abstract description 9
- 239000008367 deionised water Substances 0.000 claims abstract description 8
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 8
- 239000011812 mixed powder Substances 0.000 claims abstract description 8
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 18
- 239000002994 raw material Substances 0.000 claims description 11
- 238000007789 sealing Methods 0.000 claims description 9
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 claims description 2
- 239000000243 solution Substances 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 abstract description 42
- 238000002156 mixing Methods 0.000 abstract description 8
- WNKMTAQXMLAYHX-UHFFFAOYSA-N barium(2+);dioxido(oxo)titanium Chemical compound [Ba+2].[O-][Ti]([O-])=O WNKMTAQXMLAYHX-UHFFFAOYSA-N 0.000 description 93
- 239000004408 titanium dioxide Substances 0.000 description 17
- 238000002360 preparation method Methods 0.000 description 15
- 238000002441 X-ray diffraction Methods 0.000 description 14
- 238000000227 grinding Methods 0.000 description 14
- 238000000498 ball milling Methods 0.000 description 13
- 238000009826 distribution Methods 0.000 description 13
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 12
- 239000012071 phase Substances 0.000 description 12
- 230000008569 process Effects 0.000 description 12
- 238000010532 solid phase synthesis reaction Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 6
- 239000000919 ceramic Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000003837 high-temperature calcination Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 238000000975 co-precipitation Methods 0.000 description 4
- 125000005842 heteroatom Chemical group 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 238000001354 calcination Methods 0.000 description 3
- 238000001027 hydrothermal synthesis Methods 0.000 description 3
- 239000004570 mortar (masonry) Substances 0.000 description 3
- 238000007873 sieving Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000007790 solid phase Substances 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 229910003089 Ti–OH Inorganic materials 0.000 description 1
- 229910003088 Ti−O−Ti Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- XBYNNYGGLWJASC-UHFFFAOYSA-N barium titanium Chemical compound [Ti].[Ba] XBYNNYGGLWJASC-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- FSAJRXGMUISOIW-UHFFFAOYSA-N bismuth sodium Chemical compound [Na].[Bi] FSAJRXGMUISOIW-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005906 dihydroxylation reaction Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 229910002112 ferroelectric ceramic material Inorganic materials 0.000 description 1
- 230000005621 ferroelectricity Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 description 1
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- 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
- C04B35/468—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 barium titanates
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
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- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B2235/3215—Barium oxides or oxide-forming salts thereof
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Abstract
The invention discloses a method for synthesizing nano barium titanate-based powder in water vapor, which comprises the following steps of firstly, completely mixing powder with the molar ratio of barium to titanium of BaO and TiO2 of 0.99-1.06; secondly, placing the mixed powder into a polytetrafluoroethylene open container, and then placing the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device; thirdly, applying pressure to water and heating to generate a steam atmosphere, so that BaO and TiO2 react to synthesize barium titanate initial powder, wherein the temperature of steam in the reaction process is 110-200 ℃, and the reaction time is 1-24 hours; fourthly, firstly, washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water; fifthly, drying in a drying oven at 30-100 ℃; the tetragonal synthesized nano barium titanate-based powder with the particle size smaller than 100nm and uniform particle size can be prepared in large scale.
Description
Technical Field
The invention relates to the technical field of barium titanate-based powder synthesis, in particular to a method for synthesizing small-particle-size high-tetragonality barium titanate-based powder in water vapor at a low temperature and a solid phase, which can be used for preparing tetragonal phase barium titanate nano particles with particle sizes smaller than 100nm and uniform in particle size in a large scale.
Background
The electronics industry is BaTiO 3 The main field of application is that the powder hard agglomeration is serious due to high temperature calcination in the manufacturing process, and the surface activity is poor, so that the high-density ceramic with high dielectric constant and low loss factor is expected to be produced at low calcination temperature. The electrical properties of ceramic materials are very sensitive to their microstructure, baTiO for ceramic manufacture 3 The powder is required to have high purity, uniformity and good dispersion, and has uniform spherical particle size of not more than 200nm, and compared with cubic phase BaTiO having no ferroelectricity 3 Tetragonal BaTiO 3 The spontaneous polarization phenomenon is present, the ferroelectric property and the piezoelectricity are more excellent, and the dielectric efficiency in the capacitor is higher, so that higher requirements are put on tetragonal phase, grain size and the like of the barium titanate powder. The barium titanate powder is required to have a small particle size and high tetragonality.
The traditional method for producing nano-scale barium titanate powder is a plurality of methods, and the solid phase method, the hydrothermal synthesis method and the coprecipitation method are widely applied and are popular in industry. The traditional method has a plurality of defects, the solid phase method is the powder preparation method with the largest industrial production at present, the reaction conditions are relatively simple, the complex experimental operation flow is not needed, and complex production equipment is not needed; the solid phase method uses barium carbonate (BaCO) 3 ) And titanium dioxide (TiO) 2 ) The equimolar mixture of (2) is generally ball-milled and calcined at 850-1400 ℃, and the prepared barium titanate powder has high reaction temperature, uneven reaction, high agglomeration degree, large particle size (2-5 um), high impurity content, poor electrical properties of sintered ceramics, insufficient control on the shape and size of the generated particles, and difficult preparation of high-tetragonal nano barium titanate particles with the particle size less than 100nm under the condition of no complex process and ball milling process. Related prior patents on the preparation of nano barium titanate powder using a solid phase synthesis method have been proposed in recent years as follows:
chinese patent CN108689429a discloses a novel low-temperature solid phase synthesis method of titanate powder, which comprises mixing metallic Ti powder and solid phase powder with oxidative metal salt, and briquetting; and (3) under a certain atmosphere, carrying out heat treatment on the pressed powder blocks for a certain time at a certain temperature, and then crushing and sieving the heat-treated powder blocks to obtain the titanate powder. The method not only needs to carry out the crushing process, but also carries out the reaction for 10 to 15 hours at the temperature of 500 to 600 ℃ and has longer reaction time.
Chinese patent CN111533553a discloses a nanocrystalline barium titanate ceramic and a preparation method thereof, the preparation method is that barium carbonate and titanium dioxide are mixed, ball-milled, sanded, dried, sieved and calcined to obtain the barium titanate ceramic. But the preparation process needs ball milling and high-temperature calcination, which increases the equipment requirement.
Chinese patent CN105967227a discloses a solid phase synthesis method of barium titanate assisted by a polymer crosslinked network, which is characterized in that a polymer is dissolved in a solvent to obtain a polymer sol, titanium dioxide, barium carbonate and the solvent are weighed according to a proportion, a small amount of the polymer sol is added as a dispersing agent, zirconia beads are used as a grinding medium to perform full grinding and dispersing, slurry is prepared, the polymer sol is added into the slurry obtained after full grinding and dispersing, the mixture is fully stirred uniformly, a crosslinking agent is added, the mixture is left stand, dried to obtain a dry material, and the dry material is calcined to obtain barium titanate powder. Although the process of preparing the dry material is carried out at low temperature, calcination is finally required, and the calcination temperature is as high as 1000-1200 ℃.
Chinese patent CN110642617A is a barium titanate-based relaxation ferroelectric ceramic material with high electric field resistance and high energy storage density, which is characterized in that SrCO 3 、Bi2O 3 And TiO 2 Ball milling to obtain mixture, stoving, grinding, sieving, pre-sintering at 950 deg.c, maintaining for 3 hr, cooling to room temperature, ball milling to obtain Sr0.7Bi0.2TiO 3 The method comprises the steps of carrying out a first treatment on the surface of the BaCO is carried out 3 With TiO 2 Ball milling after mixing to obtain a mixtureMixing materials, drying, grinding, sieving, presintering at 1000 ℃, preserving heat for 4 hours, cooling to room temperature, and ball milling again to obtain BaTiO 3 . The preparation process is carried out at a relatively high temperature, and the ball milling process is carried out, so that the particle size distribution becomes too wide, and the density may be reduced.
Chinese patent CN111393161A discloses a bismuth sodium titanate strontium titanate based energy storage ceramic material and a preparation method thereof, wherein the preparation process adopts Na 2 CO 3 Powder, bi 2 O 3 Powder, tiO 2 Powder, srCO 3 Powder body and BaCO 3 Powder and Nb 2 O 5 The powder is used as raw material, the ingredients are mixed according to the stoichiometric amount, the ball milling is carried out for one time, absolute ethyl alcohol with the same quantity as the mixture is added into the mixture, and the ball milling is carried out for 12 to 24 hours, so that the powder is uniformly mixed to form slurry. Baking the slurry in a constant temperature oven, removing absolute ethyl alcohol, grinding in a mortar to obtain powder, pre-pressing the powder in a grinding tool to form a block, presintering the block at 750-800 ℃, keeping the temperature for 2-4 hours, performing secondary ball milling on the presintered block in the mortar, grinding to obtain primary powder, adding absolute ethyl alcohol equivalent to the primary powder into the obtained primary powder, continuously ball milling for 12-24 hours, uniformly mixing the powder to form slurry, drying, and grinding in the mortar to obtain the powder. The preparation process involves multiple ball milling and high temperature calcination.
Compared with a solid phase method, the hydrothermal synthesis method and the coprecipitation method can generate superfine BT powder at a lower temperature, but the hydrothermal synthesis method has the advantages of complex process, long reaction time and low yield; the coprecipitation method is that precursor sediment is prepared firstly, then thermal decomposition is carried out at a higher temperature (more than 900 ℃) to generate barium titanate powder, hard aggregates are formed among particles in the thermal decomposition process, so that the particle size of the powder is increased, and strong grinding is needed to remove the hard aggregates, but the particle size distribution becomes too wide in the strong grinding process, the density is possibly reduced, and some dielectric properties are adversely affected; in addition, since a large amount of fine particles are generated in the process of intense grinding, powder is difficult to disperse during forming, and abnormal growth of crystal grains can be observed in the process of sintering, the coprecipitation method is difficult to prepare barium titanate powder with small particle size.
Disclosure of Invention
Aiming at the technical problems, the invention aims to provide a method for synthesizing nano barium titanate-based powder in tetragonal phase with particle size smaller than 100nm and uniform particle size in large scale.
To achieve the above object, the present invention provides a method for synthesizing nano barium titanate-based powder in water vapor, comprising the first step of mixing industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The powder with the molar ratio of barium to titanium of 0.99-1.06 is completely mixed;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate steam atmosphere to make BaO and TiO 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 110-200 ℃, the equilibrium pressure of the water vapor is 0.13-1.6 MPa, and the reaction time is 1-24 h;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at the temperature of 30-100 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 50-100 nm.
As a preference of the scheme, in the first step, the molar ratio of the raw materials BaO to TiO2 to barium and titanium is 0.99:1 or 1:1 or 1.02:1 or 1.04:1 or 1.06:1.
Further preferably, in the third step, the temperature of the water vapor in the reaction process is 110 ℃ or 130 ℃ or 150 ℃ or 200 ℃, and the water vapor equilibrium pressure corresponding to different water vapor temperatures is 143.24KPa, 270.02KPa, 475.72KPa, 1553.6KPa in sequence, and the reaction time is 1h or 2h or 3h or 6h or 24h.
Further preferably, in the fourth step, the washing is performed with an acetic acid solution 2 times and then with water or distilled water 3 times.
Further preferably, in the fifth step, the drying temperature is 70 ℃ and the drying time is 5 to 6 hours.
Further preferably, in the first step, the polytetrafluoroethylene open container is integrally arranged on a lining structure of the stainless steel sealed sterilization autoclave.
The preparation principle of the invention is as follows: water vapor in TiO 2 And BaO synthesis of BaTiO 3 Has great effect on water molecules and TiO 2 Contact will lead to H 2 The dissociation of O adsorbs and generates Ti-OH bonds and active protons; when protons are intercalated into TiO 2 In the structure, the Ti-O-Ti bond can be attacked to promote TiO 6 Migration of octahedra. With TiO 2 The dehydroxylation process occurs with an increase in the concentration of OH "groups in the volume. Under these conditions, ba 2+ Diffusion into the titania phase is facilitated by the significant increase in solid state mobility. Ba (Ba) 2+ In TiO 6 Bonding between octahedrons to finally form BaTiO 3 A phase; the combination of barium atoms and oxygen atoms results in the release of water molecules from the solid state to the gaseous state.
The invention has the beneficial effects that:
(1) The method is an improved and optimized low-temperature solid phase synthesis method, which adopts TiO 2 And BaO in steam, and the method is different from the traditional solid phase reaction method, and uses BaO and TiO 2 The mechanical mixing process of the barium titanate crystal is carried out through a solid state mechanism, and the interaction of the initial oxide and water vapor is beneficial to the migration of the structure, so that the high-temperature calcination and strong grinding are not needed in the preparation process, the agglomeration phenomenon is avoided, and the ball milling process and the high-temperature calcination are avoided.
(2) Compared with the prior art, the method solves the problems of excessively wide particle size distribution, reduced density and adverse influence on dielectric property caused by strong grinding in the prior traditional solid phase methodThe prepared powder has small average particle diameter (about 50-100 nm), high crystallinity and high tetragonality (c/a ratio) of 1.0089; baTiO 3 The powder had a dielectric constant of about 20 at 1kHz, a dielectric constant of about 13 at 1MHz, a dielectric constant of about 10 at 1-2 GHz, and a loss tangent ranging from 0.18 at 1MHz to 0.05 at 1-2 GHz.
(3) The method only needs simple devices and equipment, and has high quantitative production safety and strong operability.
Drawings
FIG. 1 shows that the raw materials of examples 1 to 5 of the present invention have barium-titanium ratios (Ba/Ti) of 0.99 (curve a), 1.00 (curve b), 1.02 (curve c), 1.04 (curve d) and 1.06 (curve e), respectively, and nano BaTiO is obtained in 24 hours under the condition of hot steam at 200 DEG C 3 X-ray diffraction (XRD) patterns of (a).
Fig. 2 is a Scanning Electron Microscope (SEM) photograph and particle size distribution of the nano barium titanate powder prepared in example 1.
Fig. 3 is a Scanning Electron Microscope (SEM) photograph and particle size distribution of the nano barium titanate powder prepared in example 2.
Fig. 4 is a Scanning Electron Microscope (SEM) photograph and particle size distribution of the nano barium titanate powder prepared in example 3.
Fig. 5 is a Scanning Electron Microscope (SEM) photograph and particle size distribution of the nano barium titanate powder prepared in example 4.
Fig. 6 is a Scanning Electron Microscope (SEM) photograph and a particle size distribution of the nano barium titanate powder prepared in example 5.
FIG. 7 shows the X-ray diffraction (XRD) patterns of nano-barium titanate obtained in examples 6 to 9 of the present invention, in which the reaction temperatures are 200 ℃ (curve a), 150 ℃ (curve b), 130 ℃ (curve c) and 110 ℃ (curve d), respectively.
Detailed Description
Example 1:
a method for synthesizing nano barium titanate-based powder in water vapor, comprising the following steps:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The molar ratio of barium to titanium is 0.99:1, completely mixing the powder;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate 100% water vapor atmosphere, so that BaO and TiO are formed 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 200 ℃, the equilibrium pressure of the water vapor is 1553.6Kpa, and the reaction time is 24 hours;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at 70 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 74nm.
The XRD pattern of the nano barium titanate prepared in this example is shown in the curve (a) of fig. 1, and it can be seen that there are significant hetero peaks at diffraction angles 2θ=29°, 35 °, 41 ℃ and the like. As shown in fig. 2, a Scanning Electron Microscope (SEM) photograph and a particle size distribution diagram of the nano barium titanate prepared in this example show that the average particle size of the nano barium titanate prepared in this example is 74nm. The tetragonality (c/a) of the nano barium titanate prepared in this example was 1.0069.
Example 2:
a method for synthesizing nano barium titanate-based powder in water vapor, comprising the following steps:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 Completely mixing the powder with the molar ratio of barium to titanium of 1:1;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
preferably, the polytetrafluoroethylene open container is integrally arranged on the lining structure of the stainless steel sealing sterilization high-pressure device.
Third, applying pressure to water and heating to generate 100% water vapor atmosphere, so that BaO and TiO are formed 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 200 ℃, the equilibrium pressure of the water vapor is 0.13-1.6 MPa, and the reaction time is 24h;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at 70 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 58nm.
The XRD pattern of the nano barium titanate prepared in this example is shown in the curve (b) of fig. 1, and it can be seen that the impurity peak is obviously disappeared, indicating the improvement of purity. As shown in fig. 3, a Scanning Electron Microscope (SEM) photograph and a particle size distribution diagram of the nano barium titanate prepared in this example show that the average particle size of the nano barium titanate prepared in this example is 58nm. The tetragonality (c/a) of the nano barium titanate prepared in this example was 1.00896.
Example 3:
a method for synthesizing nano barium titanate-based powder in water vapor, comprising the following steps:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The powder with the molar ratio of barium to titanium of 1.02:1 is completely mixed;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate 100% water vapor atmosphere, so that BaO and TiO are formed 2 Reacting to synthesize barium titanate initial powderThe temperature of the water vapor in the reaction process is 200 ℃, the equilibrium pressure of the water vapor is 0.13 MPa-1.6 MPa, and the reaction time is 24 hours;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at 70 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 62nm.
The XRD pattern of the nano-barium titanate prepared in this example is shown in curve (c) of fig. 1, and it can be seen that a hetero peak occurs at diffraction angle 2θ=29° compared to Ba/Ti molar ratio=1.000. As shown in fig. 4, a Scanning Electron Microscope (SEM) photograph and a particle size distribution diagram of the nano barium titanate prepared in this example show that the average particle size of the nano barium titanate prepared in this example is 62nm. The tetragonality (c/a) of the nano barium titanate prepared in this example was 1.00753.
Example 4:
a method for synthesizing nano barium titanate-based powder in water vapor, comprising the following steps:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The powder with the molar ratio of barium to titanium of 1.04:1 is completely mixed;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate 100% water vapor atmosphere, so that BaO and TiO are formed 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 200 ℃, the equilibrium pressure of the water vapor is 0.13-1.6 MPa, and the reaction time is 24h;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at 70 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 83nm.
The XRD pattern of the nano-barium titanate prepared in this example is shown in the curve (d) of fig. 1, and it can be seen that hetero peaks appear at various diffraction angles compared with Ba/Ti molar ratio=1.000. As shown in fig. 5, a Scanning Electron Microscope (SEM) photograph and a particle size distribution diagram of the nano barium titanate prepared in this example show that the average particle size of the nano barium titanate prepared in this example is 83nm. The tetragonality (c/a) of the nano barium titanate prepared in this example was 1.0068.
Example 5:
a method for synthesizing nano barium titanate-based powder in water vapor, comprising the following steps:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The powder with the molar ratio of barium to titanium of 1.06:1 is completely mixed;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate 100% water vapor atmosphere, so that BaO and TiO are formed 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 200 ℃, the equilibrium pressure of the water vapor is 0.13-1.6 MPa, and the reaction time is 24h;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at 70 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 65nm.
The XRD pattern of the nano barium titanate prepared in this example is shown in the curve (e) of fig. 1, and it can be seen that the diffraction peak appears at a plurality of diffraction angles compared with the molar ratio of Ba/ti=1.000, and the powder hetero peak diffraction peak is more sharp compared with the molar ratio of Ba/ti=1.004. As shown in fig. 6, a Scanning Electron Microscope (SEM) photograph and a particle size distribution diagram of the nano barium titanate prepared in this example, it can be seen that the average particle size of the nano barium titanate prepared in this example is 65nm. The tetragonality (c/a) of the nano barium titanate prepared in this example was 1.0069.
FIG. 7 (a) shows the XRD pattern of the synthesized nano barium titanate-based powder, in which the molar ratio of barium to titanium is example 2, the temperature of water vapor is 200℃and the equilibrium pressure of water vapor is 1553.6KPa during the reaction, and the purity of the nano barium titanate-based powder prepared at 200℃is highest.
FIG. 7 (b) shows the XRD pattern of the synthesized nano barium titanate-based powder when the molar ratio of barium to titanium in the preparation method is example 2 and the temperature of water vapor is 150℃and the equilibrium pressure of water vapor is 475.72KPa, and the purity of the nano barium titanate-based powder prepared under the reaction condition of 150℃is lower than that of the nano barium titanate-based powder prepared under the condition of 200℃as compared with the many peaks occurring in the diffraction image of the nano barium titanate-based powder prepared under the temperature of 200 ℃.
FIG. 7 (c) shows the XRD pattern of the synthesized nano barium titanate-based powder when the molar ratio of barium to titanium in the preparation method is example 2 and the temperature of water vapor is 130℃and the equilibrium pressure of water vapor is 270.02KPa, and the purity of the nano barium titanate-based powder prepared at 130℃is lower than that of the nano barium titanate-based powder prepared at 200℃compared with the XRD pattern of the nano barium titanate-based powder prepared at 200 ℃.
FIG. 7 (d) shows the XRD pattern of the synthesized nano barium titanate-based powder when the molar ratio of barium to titanium in the preparation method is example 2 and the temperature of water vapor is 110℃and the equilibrium pressure of water vapor is 143.24KPa, compared with the XRD pattern of the nano barium titanate-based powder prepared at 200℃in which many peaks appear, the purity of the nano barium titanate-based powder prepared at 110℃is lower than that of the nano barium titanate-based powder prepared at 200 ℃.
By combining the above examples and XRD patterns, it can be seen that the purity of the synthesized nano barium titanate-based powder is highest when the temperature of water vapor in the reaction process is 200 ℃, the equilibrium pressure of water vapor is 1553.6KPa, and the reaction time is 24 hours.
Claims (6)
1. The method for synthesizing the nano barium titanate-based powder in the water vapor is characterized by comprising the following steps of:
in a first step, industrial BaO and TiO 2 Taking BaO and TiO as raw materials 2 The powder with the molar ratio of barium to titanium of 0.99-1.06 is completely mixed;
secondly, putting the completely dried mixed powder into a polytetrafluoroethylene open container, and then putting the polytetrafluoroethylene open container into a stainless steel sealed sterilization high-pressure device; meanwhile, 1/3-2/3 of water is filled between the polytetrafluoroethylene open container and the stainless steel sealed sterilization high-pressure device;
third, applying pressure to water and heating to generate steam atmosphere to make BaO and TiO 2 Reacting to synthesize barium titanate initial powder, wherein the temperature of water vapor is 110-200 ℃, the equilibrium pressure of the water vapor is 0.13-1.6 MPa, and the reaction time is 1-24 h;
step four, opening a stainless steel sealing sterilization high-pressure device, taking out the prepared barium titanate initial powder from the polytetrafluoroethylene open container, and washing the barium titanate initial powder with acetic acid solution and then with deionized water or distilled water;
and fifthly, drying the washed barium titanate in a drying oven at the temperature of 30-100 ℃ to obtain tetragonal phase synthesized nano barium titanate-based powder with the particle size of 50-100 nm.
2. The method for synthesizing nano barium titanate-based powder in water vapor according to claim 1, wherein: in the first step, the raw materials BaO and TiO 2 The molar ratio of barium to titanium is 0.99:1 or 1:1 or 1.02:1 or 1.04:1 or 1.06:1.
3. The method for synthesizing nano barium titanate-based powder in water vapor according to claim 2, wherein: in the third step, the temperature of the water vapor in the reaction process is 110 ℃ or 130 ℃ or 150 ℃ or 200 ℃, and the water vapor equilibrium pressure corresponding to different water vapor temperatures is 143.24KPa, 270.02KPa, 475.72KPa and 1553.6KPa in sequence, and the reaction time is 1h or 2h or 3h or 6h or 24h.
4. The method for synthesizing nano barium titanate-based powder in water vapor according to claim 3, wherein: in the fourth step, the aqueous solution is washed with acetic acid 2 times and then with water or distilled water 3 times.
5. The method for synthesizing nano barium titanate-based powder in water vapor according to claim 1, wherein: in the fifth step, the drying temperature is 70 ℃ and the drying time is 5-6 h.
6. The method for synthesizing nano barium titanate-based powder in water vapor according to claim 1, wherein: in the first step, the polytetrafluoroethylene open container is integrally arranged on a lining structure of a stainless steel sealing sterilization high-pressure device.
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| CN103570060A (en) * | 2013-11-08 | 2014-02-12 | 蚌埠玻璃工业设计研究院 | Preparation process of nano barium titanate |
| CN105439196A (en) * | 2015-12-24 | 2016-03-30 | 广东工业大学 | Low-temperature preparation method of high-tetragonal-phase-content nano barium titanate powder |
| RU2637907C1 (en) * | 2016-11-30 | 2017-12-07 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский государственный университет имени М.В. Ломоносова" (МГУ) | Method of producing fine-grained barium titanate |
| CN107954469A (en) * | 2017-12-15 | 2018-04-24 | 河北工业大学 | A kind of method for preparing tetragonal phase nano barium titanate |
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| CN103570060A (en) * | 2013-11-08 | 2014-02-12 | 蚌埠玻璃工业设计研究院 | Preparation process of nano barium titanate |
| CN105439196A (en) * | 2015-12-24 | 2016-03-30 | 广东工业大学 | Low-temperature preparation method of high-tetragonal-phase-content nano barium titanate powder |
| RU2637907C1 (en) * | 2016-11-30 | 2017-12-07 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский государственный университет имени М.В. Ломоносова" (МГУ) | Method of producing fine-grained barium titanate |
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