Barium titanate ceramic powder, method for preparing the same, and use thereof

Abstract

The application provides a barium titanate ceramic powder and a preparation method and application thereof, and belongs to the technical field of material preparation. The method comprises the following steps: mixing a barium chloride aqueous solution and a titanium chloride-containing solution, mixing the mixed solution with an organic acid solution, mixing the mixed sol solution with a surfactant solution, stirring and reacting, and sequentially performing centrifugation, drying, calcination and crushing on the stirring reaction product to obtain the barium titanate ceramic powder. Compared with the prior art, the application has the advantages that the simple co-precipitation preparation process is easy to operate and realize, the cost is low, no additional complex conditions and complex equipment are needed, the co-precipitation reaction can occur under stirring at normal temperature and pressure, the raw materials used are cheap and easy to obtain, the material preparation cost is relatively low, the particles are pure tetragonal phase crystal structures, the particle size is small, the prepared barium titanate is easy to process and sinter, and therefore the barium titanate can be used for manufacturing electronic ceramic devices, filter ceramic devices and various purposes.

Description

Technical Field

[0001] This invention relates to the field of materials preparation, and in particular to a barium titanate ceramic powder, its preparation method, and its application. Background Technology

[0002] Barium titanate ceramics are a common and widely used dielectric ceramic material in daily life. They possess relatively high dielectric constants and good dielectric stability, and have been widely applied in many fields such as electronics, consumer goods, and biomedicine. With the expansion of application areas and the improvement of performance indicators, higher requirements are being placed on the performance of barium titanate-based ceramic materials. The performance of barium titanate ceramic powder is a crucial factor determining the dielectric ceramic products (capacitors, inductors) obtained from future processing. Therefore, the preparation of barium titanate-based ceramic powder materials with excellent performance has become a research hotspot in the field of electronic information materials.

[0003] Achieving precise control over the crystal structure, size, and morphology of barium titanate ceramics can improve their mechanical, dielectric, and thermal sintering properties. For example, in the fabrication of ceramic capacitors, the purity, particle size, crystal phase, surface structure, and morphology of barium titanate ceramic powder directly determine the yield rate and subsequent performance of the ceramic devices. The efficient preparation of high-performance barium titanate ceramic powder is currently a research hotspot and a key technical challenge.

[0004] However, existing common preparation methods often yield barium titanate ceramic powders with relatively large solid particle sizes. Even when the particle size can reach the nanoscale in liquid phase dispersion, severe agglomeration or impure crystalline phases always occur after drying, greatly limiting the development and application of barium titanate ceramic materials. The preparation and structural control of high-quality nanoscale barium titanate-based ceramic powders are key technical challenges determining the application of barium titanate-based ceramics. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a barium titanate ceramic powder, its preparation method, and its application. The barium titanate ceramic powder prepared using the method of this invention has a pure tetragonal crystal structure and a small particle size.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing barium titanate ceramic powder, comprising the following steps:

[0008] 1) Mix the barium chloride aqueous solution with the titanium chloride-containing solution to obtain a mixed solution;

[0009] 2) Mix the mixed solution obtained in step 1) with an organic acid solution to obtain a mixed sol solution;

[0010] 3) The mixed sol solution obtained in step 2) is mixed with the surfactant solution and stirred to react, resulting in a stirred reactant;

[0011] 4) The stirred reaction mixture obtained in step 3) is centrifuged, dried, calcined and pulverized in sequence to obtain barium titanate ceramic powder.

[0012] Preferably, in step 1), the volume ratio of barium chloride aqueous solution to titanium chloride solution is 500:100-200;

[0013] The mass ratio of barium chloride in the barium chloride aqueous solution to titanium chloride in the titanium chloride solution is 10:35-50.

[0014] Preferably, in step 1), the barium chloride aqueous solution and the titanium chloride solution are mixed dropwise at a rate of 20–1000 ml / min, and then stirred for 30 min after mixing.

[0015] The titanium-containing chloride includes one or more of titanium tetrachloride, titanium oxychloride, and titanium trichloride.

[0016] Preferably, the volume ratio of the organic acid solution in step 2) to the barium chloride aqueous solution in step 1) is 400:500.

[0017] The mass ratio of the organic acid in the organic acid solution to the barium chloride in the barium chloride aqueous solution is 10:10.

[0018] The organic acid includes one or more of tartaric acid, citric acid, and malic acid.

[0019] Preferably, in step 2), the mixed solution and the organic acid solution are mixed by dropwise addition at a rate of 20–1000 ml / min, and then stirred for 1 hour.

[0020] Preferably, the volume ratio of the surfactant solution in step 3) to the barium chloride aqueous solution in step 1) is 500-600:500;

[0021] The mass ratio of the surfactant in the surfactant solution to the barium chloride in the barium chloride aqueous solution is 1-2:10;

[0022] The surfactants include PEG-10000 and / or F127;

[0023] The solvent of the surfactant solution is one or more of the following: water and organic alcohols: ethanol, propanol, isopropanol, n-butanol, ethylene glycol, glycerol, and benzyl alcohol.

[0024] Preferably, in step 3), the sol solution and the surfactant solution are mixed by dropwise addition at a rate of 20–1000 ml / min.

[0025] The stirring reaction was carried out over a period of 12 hours.

[0026] Preferably, the centrifugation conditions in step 4) include: a rotation speed of 10,000 rpm and a time of 5 min;

[0027] The drying conditions include: a temperature of 70–90°C and a time of 8 hours;

[0028] The calcination conditions include: a temperature of 900℃ and a time of 4 hours;

[0029] The pulverization is a gaseous pulverization at a pressure of 10 MPa.

[0030] The present invention also provides a barium titanate ceramic powder prepared by the preparation method described in the above technical solution.

[0031] The present invention also provides the application of the barium titanate ceramic powder described in the above technical solution in the preparation of ceramic devices.

[0032] The beneficial effects of this invention are as follows:

[0033] Compared with existing technologies, this invention first reacts with titanium chloride in a mixed solvent of water and organic alcohol to produce titanate species through vigorous hydrolysis of a barium compound precursor. Subsequently, it reacts with small molecule organic acids added to the reaction system. These small molecule organic acids have a certain coordination ability, resulting in a complex precipitation-dissolution-precipitation process. In this reaction system, the small molecule organic acids, organic alcohols, and surfactants play crucial roles. Their presence not only weakens the interaction between sol particles but also changes the surface state of the resulting precipitate, thereby preventing the agglomeration of precipitate particles. In addition, the crystal phase structure of barium titanate is effectively regulated. Subsequent gas-state pulverization technology can effectively remove particle agglomeration in the product and effectively control the particle size distribution. Compared with traditional methods for synthesizing barium titanate ceramic powder, this invention has strong controllability, a simple process, convenient operation, and low cost. Moreover, the entire preparation reaction process is carried out under static conditions at room temperature, which is energy-saving and environmentally friendly. The pure crystalline phase nano-sized barium titanate ceramic powder obtained has an irregular particle morphology, an uneven surface, good particle dispersion, uniform particle size, and small particle size, which has broad application prospects, especially in the field of ceramic device processing in the electronic information industry. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0035] Figure 1The image shows a characteristic transmission electron microscope (TEM) image of barium titanate ceramic powder material with pure crystalline phase and particle size (D90) less than 200 nm obtained by this preparation method, which was prepared in Example 1.

[0036] Figure 2 The large-angle X-ray spectrum of barium titanate ceramic powder material, which is a monodisperse pure crystalline phase with a particle size (D90) of less than 200 nm, was obtained from Example 1. Detailed Implementation

[0037] This invention provides a method for preparing barium titanate ceramic powder, comprising the following steps:

[0038] 1) Mix barium chloride aqueous solution with titanium chloride aqueous solution to obtain a mixed solution;

[0039] 2) Mix the mixed solution obtained in step 1) with an organic acid solution to obtain a mixed sol solution;

[0040] 3) The mixed sol solution obtained in step 2) is mixed with the surfactant solution and stirred to react, resulting in a stirred reactant;

[0041] 4) The stirred reaction mixture obtained in step 3) is centrifuged, dried, calcined and pulverized in sequence to obtain barium titanate ceramic powder.

[0042] This invention involves mixing an aqueous solution of barium chloride with a solution containing titanium chloride to obtain a mixed solution.

[0043] In this invention, the volume ratio of the barium chloride aqueous solution to the titanium chloride-containing solution is preferably 500:100-200. In this invention, the mass ratio of barium chloride in the barium chloride aqueous solution to titanium chloride in the titanium chloride-containing solution is preferably 10:35-50. In this invention, the barium chloride aqueous solution and the titanium chloride-containing solution are preferably mixed dropwise at a rate of 20-1000 ml / min, followed by stirring for 30 min. In this invention, the titanium chloride preferably includes one or more of titanium tetrachloride, titanium oxychloride, and titanium trichloride.

[0044] In this invention, the water used is preferably water that has undergone water purification and ion removal treatment, wherein the heavy metal ions, iron, cobalt and nickel ions are below 100 ppm.

[0045] The present invention mixes the obtained mixed solution with an organic acid solution to obtain a mixed sol solution.

[0046] In this invention, the volume ratio of the organic acid solution to the barium chloride aqueous solution is preferably 400:500. In this invention, the mass ratio of the organic acid in the organic acid solution to the barium chloride in the barium chloride aqueous solution is preferably 10:10. In this invention, the organic acid preferably includes one or more of tartaric acid, citric acid, and malic acid. In this invention, the mixed solution and the organic acid solution are preferably mixed dropwise at a rate of 20–1000 ml / min, and then stirred for 1 hour.

[0047] In this invention, the obtained mixed sol solution is mixed with a surfactant solution and stirred to react, resulting in a stirred reaction product.

[0048] In this invention, the volume ratio of the surfactant solution to the barium chloride aqueous solution is preferably 500-600:500. In this invention, the mass ratio of the surfactant in the surfactant solution to the barium chloride in the barium chloride aqueous solution is preferably 1-2:10. In this invention, the surfactant preferably includes PEG-10000 and / or F127. In this invention, the mixed sol solution and the surfactant solution are preferably mixed dropwise at a rate of 20-1000 ml / min. In this invention, the stirring reaction time is preferably 12 h. In this invention, the solvent for the surfactant is preferably water and an organic alcohol, wherein the organic alcohol includes one or more of ethanol, propanol, isopropanol, n-butanol, ethylene glycol, glycerol, and benzyl alcohol.

[0049] The present invention involves centrifuging, drying, calcining and pulverizing the stirred reaction mixture in sequence to obtain barium titanate ceramic powder.

[0050] In this invention, the centrifugation conditions preferably include: a rotation speed of 10,000 rpm and a time of 5 min.

[0051] In this invention, the drying conditions preferably include a temperature of 70–90°C and a time of 8 hours. In this invention, the calcination conditions preferably include a temperature of 900°C and a time of 4 hours. In this invention, the pulverization is preferably gaseous pulverization, and the pressure is preferably 10 MPa.

[0052] In this invention, the containers used for mixing or reaction are preferably glass containers, organic plastic containers, or ceramic-enamel containers, including one or more of the following: glass flasks, glass beakers, watch glasses, conical flasks, wide-mouth bottles, weighing bottles, test tubes, measuring cups, plastic beakers, ceramic reaction vessels, enamel reaction vessels, and centrifuge tubes. Preferably, after centrifugation, the precipitate is washed, and the solvent used for washing is preferably one or more of water, methanol, ethanol, and isopropanol. In this invention, the calcination is preferably performed in an air atmosphere, requiring a continuous air compressor to blow air in. In this invention, the pulverization is preferably gaseous pulverization, and the equipment selected for gaseous grinding is an air jet mill with a power of 5KW. The powder product is collected by a cyclone separator, and the air compressor has a power of 100KW to provide 10.0Mpa compressed air for pulverization.

[0053] This invention also provides barium titanate ceramic powder prepared by the preparation method described in the above technical solution. In this invention, the barium titanate ceramic powder has a particle size of 30–200 nm (observed under an electron microscope), and after drying and gas-state pulverization, the particle size D90 is less than 200 nm, and the specific surface area is 3–30 m². 2 / g, apparent density is 3.5-4.5g / cm³ 3 .

[0054] The present invention also provides the application of the barium titanate ceramic powder described in the above technical solution in the preparation of ceramic devices.

[0055] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] 10g of barium chloride was dissolved and dispersed in 500ml of water under stirring for 30 minutes. Then, 100ml of an aqueous solution containing 40g of titanium tetrachloride was added to the solution via a peristaltic pump, and stirring continued for 1 hour. Next, 10g of tartaric acid was dissolved in 400ml of water under stirring and added to the mixture via a peristaltic pump, and the reaction was continued for 1 hour. Then, 1.0g of PEG-10000 was dissolved in 300ml of water and 200ml of ethanol under stirring and added to the reaction system via a peristaltic pump, and the reaction was continued for 12 hours. The resulting gel solution was centrifuged at 10000rpm for 5 minutes to obtain the gel. The gel was then washed twice with water and ethanol, dried in air at 70℃ for 8 hours, calcined at 900℃ for 4 hours, and then processed using a gas pulverizer at 10.0MPa. The powder sample collected by a cyclone separator yielded nano-sized barium titanate ceramic powder (e.g., ...). Figure 1 As shown), through XRD ( Figure 2Characterization revealed that the material is a pure tetragonal barium titanate dielectric ceramic powder. Laser particle size distribution testing showed that the powder's D90 was approximately 180 nm, exhibiting a smaller particle size compared to commercially available barium titanate powders. Subsequent cooling, pressing, debinding, and sintering yielded ceramic sample sheets. Testing of the dielectric properties of these ceramic sample sheets showed a quality factor exceeding 5000, higher than currently available commercially available barium titanate-based dielectric ceramic powder samples. Its morphology and properties are shown below. Figures 1-2 As shown.

[0058] Example 2

[0059] 10g of barium chloride was dissolved and dispersed in 500ml of water under stirring for 30 minutes. Then, 100ml of an aqueous solution containing 50g of titanium trichloride was added to the solution using a peristaltic pump, and stirring was continued for 1 hour. Next, 10g of oxalic acid was dissolved in 400ml of water under stirring, and then added to the mixture using a peristaltic pump. The reaction system was stirred for another 1 hour. Finally, 1.0g of… PEG-40000 was dissolved in 300 ml of water and 200 ml of ethanol under stirring conditions, and added to the above reaction system using a peristaltic pump. After stirring and reacting for 12 hours, the resulting gel solution was centrifuged at 10000 rpm for 5 minutes to separate the gel. The gel was then washed twice with water and twice with ethanol, dried in air at 90°C for 8 hours, calcined at 900°C for 4 hours, and then processed using a gas pulverizer at a gas pressure of 10.0 MPa. The powder sample collected by a cyclone separator yielded nano-sized barium titanate ceramic powder. XRD characterization revealed that the material was pure tetragonal barium titanate dielectric ceramic powder. Laser particle size distribution testing showed that the D90 of the powder was approximately 190 nm, exhibiting a smaller particle size compared to commercially available barium titanate powder. Subsequent cooling, pressing, debinding, and sintering yielded ceramic sample sheets. Testing of the dielectric properties of the ceramic sample sheets showed a quality factor exceeding 6000, higher than currently available commercially available barium titanate-based dielectric ceramic powder samples.

[0060] Example 3

[0061] 10g of barium chloride was dissolved and dispersed in 500ml of water under stirring. After stirring for 30 minutes, 200ml of an aqueous solution containing 35g of titanium trichloride was added to the above solution via a peristaltic pump, and stirring was continued for 1 hour. Then, 10g of citric acid was dissolved in 400ml of water under stirring, and then added to the above mixed solution via a peristaltic pump. The reaction system was stirred for 1 hour, and then 1.0g of... PEG-10000 was dissolved in 300 ml of water and 300 ml of ethanol under stirring conditions, and added to the above reaction system using a peristaltic pump. After stirring and reacting for 12 hours, the resulting gel solution was centrifuged at 10000 rpm for 5 minutes to separate the gel. The gel was then washed twice with water and twice with ethanol, dried in air at 70°C for 8 hours, calcined at 900°C for 4 hours, and then processed by a gas pulverizer at a gas pressure of 10.0 MPa. The powder sample collected by a cyclone separator yielded nano-sized barium titanate ceramic powder. XRD characterization revealed that the material was pure tetragonal barium titanate dielectric ceramic powder. Laser particle size distribution testing showed that the D90 of the powder was approximately 190 nm, exhibiting a smaller particle size compared to commercially available barium titanate powder. Subsequent cooling, pressing, debinding, and sintering yielded ceramic sample sheets. Testing the dielectric properties of the ceramic sample sheets showed a quality factor exceeding 8000, higher than currently available commercially available barium titanate-based dielectric ceramic powder samples.

[0062] Example 4

[0063] 10g of barium chloride was dissolved and dispersed in 500ml of water under stirring. After stirring for 30 minutes, 100ml of an aqueous solution containing 40g of titanium tetrachloride was added to the above solution via a peristaltic pump, and stirring was continued for 1 hour. Then, 10g of malic acid was dissolved in 400ml of water under stirring, and then added to the above mixed solution via a peristaltic pump. The reaction system was stirred for 1 hour, and then 2.0g of... F127 was dissolved in 300 ml of water and 200 ml of n-butanol under stirring conditions, and added to the above reaction system using a peristaltic pump. After stirring and reacting for 12 hours, the resulting gel solution product was centrifuged at 10,000 rpm for 5 minutes to separate the gel. The gel was then washed twice with water and twice with ethanol, dried in air at 70°C for 8 hours, calcined at 900°C for 4 hours, and then processed by a gas pulverizer at a gas pressure of 10.0 MPa. The powder sample collected by the cyclone separator yielded nano-sized barium titanate ceramic powder. XRD characterization revealed that the material was pure tetragonal barium titanate dielectric ceramic powder. Laser particle size distribution testing showed that the D90 of the powder was approximately 170 nm, which is smaller than that of commercially available barium titanate powder. Subsequent cooling, pressing, degreasing, and sintering were used to obtain ceramic sample sheets. The dielectric properties of the ceramic sample sheets were tested, and the quality factor reached over 9000, which is higher than that of currently available commercially available barium titanate-based dielectric ceramic powder samples.

[0064] Comparative Example 1

[0065] 15g of barium chloride was dissolved and dispersed in 500ml of water under stirring for 30 minutes. Then, 120ml of an aqueous solution containing 60g of titanium tetrachloride was added to the solution via a peristaltic pump, and stirring continued for 1 hour. Next, 10g of oxalic acid was dissolved in 400ml of water under stirring and added to the mixture via a peristaltic pump. The reaction was continued for 12 hours. The resulting gel solution was centrifuged at 10000rpm for 5 minutes to obtain the gel. The gel was then washed twice with water, dried in air at 70℃ for 8 hours, calcined at 800℃ for 4 hours, and then processed using a gas pulverizer at a gas pressure of 10.0MPa. The powder sample collected by a cyclone separator yielded barium titanate ceramic powder with a D50 of 350nm. Characterization revealed that the material, in addition to the tetragonal barium titanate phase, also contained impurity phases such as BaTi2O5. Subsequent cooling, pressing, degreasing, and sintering yielded ceramic sample sheets. Testing the dielectric properties of the ceramic sample sheets showed a quality factor of only 1000.

[0066] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing barium titanate ceramic powder, characterized in that, Includes the following steps: 1) Dissolve and disperse 10g of barium chloride in 500ml of water under stirring. After stirring for 30min, add 100ml of aqueous solution containing 40g of titanium tetrachloride dropwise at a rate of 20-1000ml / min. Continue stirring for 1h to obtain a mixed solution. 2) Dissolve 10g of malic acid in 400ml of water by stirring, and add it dropwise to the mixed solution in step 1) at a rate of 20-1000ml / min. Continue stirring for 1 hour to obtain a mixed sol solution. 3) Dissolve 2.0g of F127 in 300ml of water and 200ml of n-butanol by stirring. Add the solution dropwise to the mixed sol solution in step 2) at a rate of 20-1000ml / min. Then continue stirring the reaction at room temperature for 12h to obtain the stirred reaction product. 4) The stirred reaction mixture obtained in step 3) was centrifuged at 10,000 rpm for 5 min to separate the gel. After washing twice with water and ethanol, it was dried at 70°C for 8 h, then calcined at 900°C in air for 4 h. Finally, it was gas-phase pulverized using an air jet mill at a gas pressure of 10.0 MPa and collected by a cyclone separator to obtain the barium titanate ceramic powder. The barium titanate ceramic powder has a pure tetragonal phase crystal structure, and the quality factor of the ceramic sample obtained by the barium titanate ceramic powder after subsequent cold isostatic pressing, degreasing and sintering is ≥9000.

2. A barium titanate ceramic powder prepared by the preparation method according to claim 1.

3. The application of the barium titanate ceramic powder as described in claim 2 in the preparation of ceramic devices.

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