JP2005330112A - Method for producing barium titanate powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high quality barium titanate using inexpensive starting materials under safe working environment. <P>SOLUTION: The barium titanate(BaTiO<SB>3</SB>) powder of a cubic structure is obtained by the steps of preparing titanium tetrachloride and barium hydroxide as starting materials, adding potassium hydroxide to these to adjust a reaction solution into strong alkalinity, then pouring nitrogen into the reactor under normal pressure, heating the solution to 80-102°C and thoroughly stirring the solution while maintaining the temperature to carry out a hydraulic circulating stream reaction, and finally treating with an ion-exchange resin and drying. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a method for producing a barium titanate powder, and in particular, a method for producing a barium titanate powder by utilizing a hydrothermal convection reaction at normal pressure.

  With the rapid change of the times, the design of electronic products is changing toward “light, thin and short”, and the speed is a thousand moments a day. Looking at these ever-changing electronics industries, high capacity, high speed and high reliability are now essential conditions for electronic products, and materials with high dielectric constants are the best solution to meet these requirements. I know that there is. Early researchers used steatite as the dielectric, but the dielectric constant was very low. In the 1925s, commercial titanium dioxide ceramic capacitors with a dielectric constant exceeding 10 appeared, and during the following World War II, the discovery of barium titanate caused the dielectric constant of ceramic capacitors to be several thousand. Rose to. Barium titanate has high dielectric constant and piezoelectric constant, low dielectric loss, high impedance, electromechanical coupling coefficient, and AC constant, and polarity, making it a high-tech electronic product of this century. Has become an indispensable electronic material. In addition to multilayer ceramic capacitors (MLCC), barium titanate can be used in a wide range of applications, from resistors, resonators, thermistors, tone transducers and semiconductor ceramics to electromagnetic wave absorbers. Has been. Existing methods for producing barium titanate materials include solid methods, precipitation methods, sol-gel methods, high-temperature and high-pressure hydrothermal methods, and these production methods will be described next. In the solid method, barium carbonate and a titanium dioxide raw material are mixed to produce a barium titanate material by a calcination reaction at a high temperature. The barium titanate material produced by this method is not very applicable to electronic products because of its low purity, large particle size and non-uniform distribution.

In the production method by the precipitation method, the reaction is accelerated by improving the diffusion distance of atoms generated during the reaction by the solid method. In this method, a cation required for the reaction is mixed in a solution according to a ratio and stirred uniformly, and a chemical reaction is induced by using a precipitant to form a precipitate. By using this method, the distance between cations is reduced from the micrometer level to the nanometer level, so that barium titanate powder can be obtained by a calcination reaction at a low temperature. Barium titanate produced by the precipitation method is further divided into an oxalate method and a citrate method depending on the precipitant used. Scholars such as Kim Et Hall and Park Et Hall produced barium titanate using the oxalate method. This uses titanium tetrachloride, barium chloride and oxalic acid or oxalic acid dimethyl ester as starting materials to produce oxalate precipitates [(BaTiO (C ₂ O ₄ ) ₂ 4H ₂ O)]. When placed in a high temperature furnace and calcined, the oxalate precipitate is decomposed to produce cubic barium titanate. Thereafter, further heat treatment is performed to obtain tetragonal form of barium titanate. Since this method is relatively simple in production process, it is generally emphasized and the production method has already been commercialized, but the product obtained by this method has a particle size in the micrometer level or less, and Since the particle size distribution is wide, the particle aggregation is extremely large, and the quality is inferior, it is unsuitable for electronic products that currently require high reliability (for example, see Non-Patent Document 1 and Non-Patent Document 2). ).

On the other hand, the citrate method is similar to the manufacturing process of the oxalate method, and its main procedure is to use tetrabutyltitanium / alkoxide [Ti (OC ₄ H ₉ ) ₄ ] and citric acid as raw materials. Citrate [BaTi (C ₆ H ₆ O ₇ ) ₃ 6H ₂ O] crystallized by adjusting the pH value by dissolving it in ethylene glycol and mixing with barium carbonate (BaCO ₃ ) in an aqueous formic acid solution. Finally, barium titanate is obtained by performing thermal treatment and gradually decomposing. The properties of the material obtained by this method are similar to the oxalate method, but this method uses expensive alkoxide titanium and organic solvent as the starting materials, so the cost performance is extremely low. Yes. Thereafter, the sol-gel method was developed, and the disadvantage that cations could not be precipitated simultaneously due to the excessive saturation difference of the precipitation method was improved (for example, see Non-Patent Document 3). In the sol-gel method, in order to sufficiently mix the cationic alcoholate necessary for the reaction, a sol is generated by a hydrolysis reaction caused by hydrolysis, a gel is generated by removing the solvent and generating polymerization, The dried calcination reaction is performed. Cationic alcoholate and water undergo a rapid hydrolysis reaction, and the substance M (OR) x-1 (OH) and alkoxide, or the substance itself undergo a polymerization reaction, so each cation can precipitate crystals simultaneously. Stoichiometric products can be obtained. To produce high-purity barium titanate by the sol-gel method using alkoxide using titanium or barium as a raw material, there are several methods described below.

(a) Alkoxide derived powders: This method uses Ti (OR ₁ ) ₄ and Ba (OR ₂ ) ₂ to cause a hydrolysis reaction to produce ultrafine, high-purity barium titanate. It produces crystal powder, and the remaining carbonates by incineration with an inert gas (500 to 700 ° C.) are incinerated to avoid the production of BaCO ₃ . The reaction formula is as follows:
Ti (OR ₁ ) ₄ + Ba (OR ₂ ) ₂ + 3H ₂ O → BaTiO ₃ + 4R ₁ OH + 2R ₂ OH
The purity of the product obtained by this method is higher than that of oxalate and citrate, but the main disadvantage is that the cost of alkoxide raw material is high, and alkoxide is very sensitive to water. That is.

(b) Alkoxide-derived Gels method: This method is a modification of the above-described alkoxide-derived powder method. First, titanium alkoxide [Ti (OR) ₄ ] and barium alkoxide are used. Side [Ba (OR) ₂ ] is formed in an amorphous gel (Amorphous Gel) in a low temperature state, and then this gel compound is calcined at a high temperature (400 to 600 ° C. or higher) to form a barium titanate crystal. .

(c) Sol-Precipitation method: This method first produces a white precipitate of titanyl Acylate Precursor with titanium alkoxide [Ti (OR) ₄ ] and acetic acid. As such, this prepolymer can be a polymer and can be dissolved in large amounts of water to form Hydroxy Titanium Acylate compounds that hydrolyze titanium alkoxide. Can be difficult. In this method, barium acetate, which is inexpensive and not very sensitive to moisture, is used as a raw material, and it can be mixed with a titanyl acylate precursor to obtain a barium titanium sol. By adding, cubic barium titanate with high purity can be obtained.

   (d) Sol-Gel method: This method is somewhat similar to the sol-precipitation method described above, but without the addition of water after the formation of a white precipitate of titanyl acylate precursor, An amorphous barium titanate gel can be obtained by adding a barium acetate solution directly to cause a gelation reaction at 25 to 70 ° C., and finally calcining at 700 to 1000 ° C. to form tetrahedral titanate Barium is obtained.

As can be seen from the above, the sol-gel method uses relatively expensive titanium or barium alkoxide as a raw material, so the cost is high and the chemical properties are unstable, making it difficult to adjust in the manufacturing process. Therefore, difficulties arise in mass production. In order to carry out the reaction while keeping the cation at the atomic level, a highly reactive hydrothermal method can be used. This method usually involves the steps of placing the reactant solution in a closed reactor and increasing the temperature and pressure to promote cation chemical reaction and obtaining solids by solid-liquid separation techniques. Depending on the reaction, the reaction can be completed by calcination. The reaction by the hydrothermal method causes partial dissolution of the reactants in a high temperature and high pressure state, and further, in this environment, a thermal decomposition or oxidation reaction is generated to produce a necessary crystal powder. The synthesis of barium acid has been a major research theme for scholars in recent years. However, the method for producing barium titanate by hydrothermal reaction in a high temperature and high pressure state is expensive in production equipment and low in safety, and the powder is not a continuous process and can be produced only in lot units.
J. Marter Science [J. Mater. Sci. (Kim et al.) 31 (1996) 3643-3645] J. Am. Ceram. Soc. (Park et al.) 80 (1997) pp. 1599-1604 J. Am Seram Society (J. Am. Ceram. Soc. (Tsay and Fang), 79 (1996) pp. 1693-1696)

  In view of the above known technical problems, the problem to be solved by the present invention is to provide a method for producing high-quality barium titanate using a low-cost starting material under a safe working environment. is there.

The production method of the present invention has researched and developed a method for synthesizing barium titanate by using a low-cost inorganic salt as a starting material and subjecting it to hydrothermal recirculation reaction at normal pressure, thereby producing high-quality titanium at low cost. Barium acid powder can be produced in large quantities.
In the method for producing a barium titanate powder material in the present invention, first, titanium tetrachloride diluted with aqueous ammonia is hydrolyzed, then a barium hydroxide solution is added, and the reaction solution is adjusted to a strong alkali range with potassium hydroxide. By adding nitrogen to the reaction vessel at normal pressure, the solution is heated to 80 to 102 ° C. and stirred sufficiently while maintaining this, so that hydrothermal circulation Cause a reaction. As a final step, high quality barium titanate powder can be obtained by drying with treatment with an anion / cation exchange resin. More specifically, (1) In the method for producing barium titanate powder,
(A) preparing a titanium tetrachloride solution;
(B) adding a large amount of aqueous ammonia to the titanium tetrachloride solution for hydrolysis;
(C) adding a barium hydroxide solution to the titanium tetrachloride solution;
(D) adding potassium hydroxide to the titanium tetrachloride solution to make the solution strongly alkaline; and (e) heating the titanium tetrachloride solution to the reaction temperature at normal pressure and in a state where nitrogen is injected. And maintaining the stability of the reaction temperature, performing a hydrothermal circulation reaction to generate a substance,
(F) upon completion of the hydrothermal recirculation reaction, a step of obtaining the barium titanate powder by treating the substance with an ion exchange resin to a substantially neutral state and further performing a drying treatment. A method for producing barium titanate powder.
(2) The method for producing a barium titanate powder as described in (1) above, wherein, in the step (a), the concentration of the titanium tetrachloride is 5 to 20 w%.
(3) In the step (b), the concentration of the ammonia water is 20 to 28% by weight, The method for producing barium titanate powder according to item 1 or 2,
(4) The barium titanate powder according to any one of (1) to (3) above, wherein in the step (b), the molar ratio of the ammonia water to the titanium tetrachloride is 4 to 8. Body manufacturing method.
(5) In the step (c), the molar ratio of the barium hydroxide to the titanium tetrachloride is 1.0 to 1.4. Production method of barium titanate powder.
(6) In the step (d), potassium hydroxide is in a solid state, and the addition amount thereof makes the pH value of the titanium tetrachloride solution at least 12 or more. 6. The method for producing a barium titanate powder according to any one of items 5 to 6.
(7) In the step (e), the reaction temperature of the hydrothermal circulation reaction is 80 to 102 ° C. The barium titanate powder according to any one of items 1 to 6 above, Production method.
(8) In the step (e), the reaction time of the hydrothermal circulation is about 1 to 5 hours, wherein the barium titanate powder according to any one of the first to seventh items is used. Production method.
(9) In the step (f), the temperature of the drying treatment is 100 to 120 ° C. The method for producing a barium titanate powder according to any one of items 1 to 8 above, .

  The feature of the production method of the present invention is that it is possible to effectively reduce the production cost because it uses a relatively low-priced inorganic salt as a starting material, and it is not a toxic organic solvent used in the conventional method. Since water is used as a solvent, safety in the manufacturing process is maintained. Furthermore, the low-temperature reaction at normal pressure is highly safe and the production process can be controlled continuously. Therefore, it is possible to improve the usage rate of equipment and substantially reduce the cost. Another feature of the production method of the present invention is that it has developed a barium titanate powder having a single distribution type particle size, a high surface area ratio and high crystallinity, and excellent dispersibility. Among the techniques, the defects such as non-uniform particle size distribution of the barium titanate powder by the high temperature solid method, large particle size and many aggregations are improved.

In order to make the objectives, structural features and functions of the present invention more comprehensible, the following detailed description is made together with the accompanying drawings. FIG. 1 is a flowchart showing a method for producing a barium titanate powder according to the present invention. Next, the contents will be described. First, a diluted titanium tetrachloride solution is prepared (step 10). The present invention uses titanium tetrachloride (TiCl ₄ ) as a raw material for the titanium source of the substance (barium titanate), and when producing a titanium tetrachloride aqueous solution, first, a reaction in which a small amount of water is injected with nitrogen. After putting in the vessel, add a suitable amount of titanium tetrachloride dropwise. After the addition of titanium tetrachloride is completed, dilute to the required concentration with water. The solution at this time is in a clear state. In the present invention, the concentration range of titanium tetrachloride after dilution is 5 to 20 w%, and a preferable concentration range is 6 to 8 w%. Subsequently, a large amount of aqueous ammonia is added to the titanium tetrachloride solution to be hydrolyzed (step 20). Immediately after the dilution of titanium tetrachloride in (Step 10), aqueous ammonia is added to this solution to cause hydrolysis. The concentration range of ammonia water is 20-28 w%, and titanium tetrachloride is completely hydrolyzed into titanium dioxide (TiO ₂ xH ₂ O) with crystal water. The molar ratio of the amount of ammonia water added to titanium tetrachloride needs to be 4-8, but the preferred range of the molar ratio is 6-7.

In the hydrolysis step, as ammonia water is added to the titanium tetrachloride solution, the pH value gradually becomes neutral, and gelation occurs at this time. Subsequently, after adding a large amount of aqueous ammonia to reach a pH value of 8 or more, the gel is decomposed to form a sol by sufficiently stirring. The chemical reaction formula of the aqueous solution of titanium tetrachloride hydrolyzed with aqueous ammonia (TiOCl ₂ + 2HCl) is as follows.
(1 + x) H ₂ O + TiOCl ₂ + 2HCl + 4NH ₃ → TiO ₂ xH ₂ O + 4NH ₄ Cl
Thereafter, an aqueous barium hydroxide solution is added to this solution (step 30). In this step, the barium hydroxide to be added is used as a barium source of the substance (barium titanate). Although barium hydroxide can be used at the industrial or reagent level, this type of chemical usually contains trace amounts of impurities such as barium carbonate. Thus, impurities contained therein must be removed. As a method for purifying barium hydroxide, steps such as dissolution, filtration and recrystallization of existing techniques can be employed. After the purified barium hydroxide is dissolved in an appropriate amount of water, it is added to the above-mentioned hydrolyzed sol material, but the molar ratio of the barium hydroxide to be added and titanium tetrachloride is in the range of 1.0 to 1.4. The range of molar ratio is 1.15 to 1.2. Next, potassium hydroxide is added to the solution to make the solution strongly alkaline (step 40). This step is to increase the reactivity of the substance (barium titanate) formation. Potassium hydroxide is suitable for addition in the form of a solid granule, thereby avoiding an excessively low solid substance content of the substance and improving the use efficiency of the reactor. The addition amount of potassium hydroxide is required to make the pH value of the reaction solution at least 12 or more, and the preferable pH value range is 13-14. Thereafter, nitrogen is injected into the reaction vessel at normal pressure, and the solution is heated until the solution reaches the reaction temperature and stirred sufficiently while maintaining the temperature, thereby causing a hydrothermal circulation reaction (step 50). . The purpose of injecting nitrogen into the reaction tank is to prevent carbon dioxide in the air and barium ions in the solution from reacting to produce barium carbonate, which hinders the production of the substance (barium titanate).

The reaction temperature range of this hydrothermal recirculation reaction is about 80 to 102 ° C., and the preferred temperature range is 95 to 102 ° C.
It is. The reaction time of this hydrothermal circulation is about 1 to 5 hours, and a suitable time is 1 to 3 hours. The chemical formula of the formation reaction of barium titanate in this step is as follows.
Ba (OH) ₂ + TiO ₂ xH ₂ O → BaTiO ₃ + (1 + x) H ₂ O
As a final step, upon completion of the hydrothermal recirculation reaction, the substance (barium titanate) is treated with an ion exchange resin to make it almost neutral, and further dried to obtain a barium titanate powder ( Step 60). After the hydrothermal circulation reaction is completed in (Step 50), it is cooled to room temperature and then separated into a solid and a liquid. The solid is dispersed again in water, treated with an anion-cation exchange resin, the granular material dispersed in water is neutralized, and then dried by the spraying method of existing technology. Barium powder is obtained.
Next, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to these examples.

First, 10.1 g of titanium tetrachloride is diluted to a concentration of 6.5 w%, and this is put into a reaction vessel. Thereafter, 16.5 g of 25 w% aqueous ammonia is added and hydrolyzed to obtain titanium dioxide (TiO ₂ .xH ₂ O) having crystal water, which is vigorously stirred. Next, 21.9 g of purified barium hydroxide (the barium / titanium ratio of the input material is about 1.3) is sufficiently dissolved in 50.0 g of water, and then added to the reaction vessel and mixed. Immediately thereafter, 17 g of solid potassium hydroxide is added. At this time, the pH value of the reaction solution should be 12 or more. Subsequently, nitrogen is injected into this solution at normal pressure, and after sufficient stirring, heated to 102 ° C. and kept at this temperature for 3 hours. As a final step, after completion of the reaction, the mixture is cooled to room temperature and then the solid and the liquid are separated. The solid granular material is first dispersed by adding water, treated with an anion-cation exchange resin tower, the material dispersed in water is neutralized, and then directly spray dried to evaporate the water, Barium titanate powder is obtained. FIG. 2 is an electron micrograph of the barium titanate powder obtained in Example 1. The primary particle size is about 90 nanometers and has a single distribution. The appearance is spherical, and the surface area ratio is 14.38 m ² / g. FIG. 3 is a powder diffraction graph by X-ray of the barium titanate powder of Example 1. From the graph of FIG. 3, the cubic crystal structure obtained by the production method of the present invention has a crystallinity. It can be seen that no other impurities are present.

First, 10.1 g of titanium tetrachloride is diluted to a concentration of 6.6 w%, and this is put into a reaction vessel. Thereafter, 16.2 g of 25 w% ammonia water is added to obtain titanium dioxide (TiO ₂ .xH ₂ O) having crystal water by hydrolysis, and this is vigorously stirred. Next, 21.9 g of purified barium hydroxide (the barium / titanium ratio of the input material is about 1.3) is sufficiently dissolved in 50.0 g of water, and then added to the reaction vessel and mixed. Thereafter, 29 g of solid potassium hydroxide is immediately added to increase the alkalinity of the reaction solution. Subsequently, nitrogen is injected into this solution at normal pressure, and after sufficient stirring, heated to 102 ° C. and kept at this temperature for 3 hours. As a final step, after completion of the reaction, the mixture is cooled to room temperature and then separated into a solid and a liquid. The solid granular material is first dispersed by adding water, treated with an anion-cation exchange resin tower, the material dispersed in water is neutralized, and then directly spray dried to evaporate the water, Barium titanate powder is obtained. FIG. 4 is an electron micrograph of the barium titanate powder obtained in Example 2. The material obtained in Example 2 has a primary particle size of about 73 nanometers and a single distribution. The appearance is spherical, and the surface area ratio is 25.928 m ² / g. As a result of comparing Example 2 with Example 1, it was found that the higher the alkalinity of the reaction solution, the smaller the particle size of the synthesized material and the higher the surface area ratio.

First, 10.14 g of titanium tetrachloride is diluted to a concentration of 6.5 w%, and this is put into a reaction vessel. Thereafter, 16.6 g of 25 w% aqueous ammonia is added to form titanium dioxide (TiO ₂ .xH ₂ O) having water of crystallization by hydrolysis, and this is vigorously stirred. Next, 18.41 g of purified barium hydroxide (the barium / titanium ratio of the input material is about 1.1) is sufficiently dissolved in 50.0 g of water, and then added to the reaction vessel and mixed. Thereafter, 29 g of solid potassium hydroxide is immediately added to increase the alkalinity of the reaction solution. Subsequently, nitrogen is injected into this solution at normal pressure, and after sufficient stirring, heated to 102 ° C. and kept at this temperature for 3 hours. As a final step, after completion of the reaction, the mixture is cooled to room temperature and then separated into a solid and a liquid. The solid granular material is first dispersed by adding water, treated with an anion-cation exchange resin tower, the material dispersed in water is neutralized, and then directly spray dried to evaporate the water, Barium titanate powder is obtained. FIG. 5 is an electron microscope image of the barium titanate powder obtained in Example 3. The primary particle size is about 95 nanometers, the surface area ratio is 26.16 m ² / g, it has a single distribution, and the appearance is spherical. As a result of comparing this example with three examples, it was found that the particle size of the synthesized substance increases as the barium / titanium ratio of the input material of the reaction solution decreases.

In this example, the influence of the length of the reaction time on the particle size of the barium titanate powder was examined by adjusting the length of the reaction time by hydrothermal circulation. First, 10.0 g of titanium tetrachloride is diluted to a concentration of 6.5 w%, and this is put into a reaction vessel. Thereafter, 16.5 g of 25 w% aqueous ammonia is added to form titanium dioxide (TiO ₂ .xH ₂ O) having crystal water by hydrolysis, and this is vigorously stirred. Next, 21.5 g of purified barium hydroxide (the barium / titanium ratio of the input material is about 1.29) is sufficiently dissolved in 50.0 g of water, and then added to the reaction vessel and mixed. Thereafter, 28.5 g of solid potassium hydroxide is immediately added to increase the alkalinity of the reaction solution. Subsequently, nitrogen is injected into the solution at normal pressure, and after sufficient stirring, the solution is heated to 102 ° C. to cause a circulation reaction while maintaining the temperature. In Example 4, a total of 4 experiments were performed, and the reaction times were 1 hour, 2 hours, 2.5 hours, and 4 hours, respectively. As a final step, after completion of the reaction, the mixture is cooled to room temperature and then separated into a solid and a liquid. The solid granular material is first dispersed by adding water, treated with an anion-cation exchange resin tower, the material dispersed in water is neutralized, and then directly spray dried to evaporate the water, Barium titanate powder is obtained. Table 1 shows the surface area ratio and particle size of the barium titanate powder according to the difference in reaction time (1 hour, 2 hours, 2.5 hours, 4 hours). FIG. 6 is an electron micrograph of the barium titanate powder according to the difference in reaction time (1 hour, 2 hours, 2.5 hours, 4 hours).

From Table 1 and FIG. 6, it can be seen that the influence of the difference in reaction time on the surface area ratio and particle size of the substance is not so great. Therefore, it can be said that it is possible to produce barium titanate powder having a single particle size distribution regardless of the reaction time. The contents described above are merely preferred examples of the present invention, and the scope of the present invention is not limited thereby. Accordingly, all modifications and additions made based on the scope of the present invention shall be included in the scope of the present invention.

It is a flowchart of the barium titanate powder manufacturing method in this invention. 2 is an electron micrograph of the barium titanate powder obtained in Example 1. 3 is a powder diffraction graph of X-ray of the barium titanate powder of Example 1. 3 is an electron micrograph of barium titanate powder obtained in Example 2. FIG. 4 is an electron micrograph of barium titanate powder obtained in Example 3. FIG. It is an electron micrograph of the barium titanate powder by the difference in reaction time (1 hour, 2 hours, 2.5 hours, 4 hours).

Claims (9)

In the method for producing barium titanate powder,
(A) preparing a titanium tetrachloride solution;
(B) adding a large amount of aqueous ammonia to the titanium tetrachloride solution for hydrolysis;
(C) adding a barium hydroxide solution to the titanium tetrachloride solution;
(D) adding potassium hydroxide to the titanium tetrachloride solution to make the solution strongly alkaline; and (e) heating the titanium tetrachloride solution to the reaction temperature at normal pressure and in a state where nitrogen is injected. And maintaining the stability of the reaction temperature, performing a hydrothermal circulation reaction to generate a substance,
(F) upon completion of the hydrothermal recirculation reaction, a step of obtaining the barium titanate powder by treating the substance with an ion exchange resin to a substantially neutral state and further performing a drying treatment. A method for producing barium titanate powder. 2. The method for producing barium titanate powder according to claim 1, wherein in the step (a), the concentration of the titanium tetrachloride is 5 to 20% by weight. The method for producing a barium titanate powder according to claim 1 or 2, wherein in the step (b), the concentration of the ammonia water is 20 to 28 w%. The method for producing barium titanate powder according to any one of claims 1 to 3, wherein in the step (b), the molar ratio of the ammonia water to the titanium tetrachloride is 4 to 8. . The barium titanate according to any one of claims 1 to 4, wherein in the step (c), a molar ratio of the barium hydroxide to the titanium tetrachloride is 1.0 to 1.4. Powder manufacturing method. In the step (d), potassium hydroxide is in a solid state, and the addition amount thereof makes the pH value of the titanium tetrachloride solution at least 12 or more. A method for producing the barium titanate powder according to claim 1. The method for producing a barium titanate powder according to any one of claims 1 to 6, wherein in the step (e), the reaction temperature of the hydrothermal circulation reaction is 80 to 102 ° C. The method for producing a barium titanate powder according to any one of claims 1 to 7, wherein in the step (e), the reaction time of the hydrothermal circulation is about 1 to 5 hours. The method for producing a barium titanate powder according to any one of claims 1 to 8, wherein in the step (f), the temperature of the drying treatment is 100 to 120 ° C.