Barium titaniumate particles and their manufacturing method, dispersion of barium titaniumate particles

Abstract

The present invention provides barium titanium dioxide particles with a high sintering delay effect and a method for manufacturing the same. The barium titanium dioxide particles of the perovskite structure according to the present invention have an atomic ratio of Ba to Ti, Ba / Ti, of 0.95 to 1.05, and a crystallite diameter of 5 to 25 nm.

Description

Technology Field

[0001] The present invention relates to barium titanium dioxide particles having a perovskite structure. Background Technology

[0002] Barium titaniumate particles are used as dielectric materials for electronic components or as optical materials with high refractive index and excellent transparency. Because barium titaniumate particles possess a high dielectric constant, they are utilized in multilayer ceramic capacitors (MLCCs). MLCCs have a structure in which electrode layers and dielectric layers are alternately stacked. The electrode layer contains Ni particles of 80 to 300 nm and barium titaniumate particles as a co-material. In the electrode layer, barium titaniumate particles are filled around the Ni particles. Consequently, the sintering temperature of the Ni particles increases. In other words, a sintering delay effect for the Ni particles is obtained. Consequently, the sintering temperature of the Ni particles becomes closer to the sintering temperature of the dielectric layer. As a result, the difference in shrinkage rates between the electrode layer and the dielectric layer during firing is reduced, and an MLCC with fewer cracks is obtained (see, for example, Patent Document 1).

[0003] On the other hand, it is known that in order to improve the dielectric constant of barium titaniumate particles, the barium titaniumate particles are made into a perovskite structure and the length of the c-axis of the crystal lattice is made longer than the length of the a-axis, that is, the barium titaniumate particles are made into a tetragonal system (see, for example, Patent Document 2). Prior art literature

[0004] Japanese Patent Publication No. 2005-63707 Japanese Patent Publication No. 2004-300027 The problem to be solved

[0005] In the barium titanium dioxide particles of Patent Document 2, the dielectric constant is high because the c-axis length of the perovskite structure is longer than the a-axis length. However, since the barium titanium dioxide particles are sintered after being powdered, the particle size or crystallite diameter tends to increase. Consequently, the density of the barium titanium dioxide particles filled around the Ni particles tends to decrease, making it difficult to obtain a sintering delay effect. As the difference between the sintering temperature of the dielectric layer and the sintering temperature of the Ni particles increases, cracks are more likely to occur in the MLCC.

[0006] The objective of the present invention is to provide barium titaniumate particles with a high sintering delay effect and a method for manufacturing the same. means of solving the problem

[0007] Therefore, in the present invention, for barium titaniumate particles with a perovskite structure, the atomic ratio of barium to titanium Ba / Ti is set to 0.9 to 1.1, and the crystallite diameter is set to 5 to 25 nm. The atomic ratio of barium to titanium Ba / Ti may be 0.95 to 1.05.

[0008] In addition, the ratio of the lengths of the c-axis and a-axis of the crystal lattice in the perovskite structure, c / a, is preferably 1.005 or less.

[0009] In a dispersion of barium titanium dioxide particles containing such barium titanium dioxide particles and an organic solvent, the water content is preferably less than 3 weight percent.

[0010] In addition, the method for manufacturing barium titaniumate particles includes a process of mixing barium hydroxide and alkyl cellosolve, a process of adding titanium alkoxide such that the atomic ratio of barium to titanium Ba / Ti is in the range of 0.9 to 1.1, a process of adding water, and a process of heating. Brief explanation of the drawing

[0011] Figure 1 is a structural diagram of a cyclic hydrocarbon group (R6). Specific details for implementing the invention

[0012] The barium titaniumate particles with a perovskite structure according to the present invention have an atomic ratio of barium to titanium, Ba / Ti, in the range of 0.9 to 1.1. As a result, it is difficult to generate impurities such as crystals other than the perovskite structure. In addition, the crystallite diameter of the barium titaniumate particles is 5 to 25 nm. Consequently, the crystallinity of the barium titaniumate particles is increased, and the particle size is reduced. Since these barium titaniumate particles enter the gaps between the Ni particles in the electrode layer, barium titaniumate particles exist at a high density around the Ni particles. Consequently, the sintering delay effect of Ni is enhanced. Furthermore, if the crystallite diameter is greater than 25 nm, the viscosity of the dispersion of the barium titaniumate particles described later increases. When the crystallite diameter is 5 to 25 nm, the particle size measured by a transmission electron microscope is 5 to 25 nm.

[0013] In addition, the atomic ratio of barium to titanium Ba / Ti may be 0.95 to 1.05.

[0014] In addition, the ratio of the lengths of the c-axis and a-axis of the crystal lattice (axial ratio) c / a in the perovskite structure is preferably 1.005 or less. As a result, the barium titanate particles become closer to a cubic shape. Consequently, the sintering delay effect of Ni is enhanced.

[0015] The crystal structure and crystallite diameter can be measured using the Rigaku RINT-Ultima, an X-ray diffraction measuring device. The crystal structure can be identified using the analysis software PDXL. The crystallite diameter can be calculated by measuring the half-width at the mirror index (110) near 2θ=31.5° and using Scherrer’s equation “D=Kλ / βcosθ” from the half-width β (rad). Here, D represents the crystallite diameter (Å), K represents the Scherrer constant, λ represents the X-ray wavelength (1.7889 Å), and θ represents the reflection angle.

[0016] From the results of X-ray diffraction measurements using PDXL, the lengths of the a-axis and c-axis of the perovskite structure can be determined. An axial ratio c / a of 1.003 or less is preferred. 1.001 or less is more preferred. The smaller the axial ratio c / a, the greater the sintering delay effect of Ni.

[0017] It is preferable that the barium titanate particles contain at least one element selected from Group 2, Group 3, lanthanoids, actinoids, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, Group 13, and Group 14 (hereinafter referred to as the additive element). This increases the sintering delay effect. It is more preferable that the additive element be included in an amount of 0.1 to 10 mol% when the compositional formula of barium titanate BaTiO3 is 100 mol%. This makes it easier to obtain the sintering delay effect of Ni. Furthermore, even if the additive element is included within this range, peaks other than those of the perovskite structure are not observed.

[0018] A paste for printing an electrode layer can be prepared using a dispersion of barium titanate particles. The dispersion of barium titanate particles contains barium titanate particles and an organic solvent. The moisture content of the dispersion is preferably less than 3 weight percent. If the moisture content is low, it is difficult to increase the viscosity of the paste even if a binder such as ethylcellulose is added to the dispersion. If the viscosity of the paste is high, it is difficult to apply the paste uniformly, so cracks are likely to occur in the electrode layer during firing. In addition, if the moisture content of the dispersion is 3 weight percent or less, the dispersion becomes difficult to aggregate.

[0019] The amount of moisture adsorbed onto the solid of the dispersion (adsorbed moisture amount) is preferably 5 parts by mass or more per 100 parts by mass of the solid. When the adsorbed moisture amount is within this range, the barium titanate particles in the dispersion have many hydroxyl groups on their surface. The solid is obtained by drying the dispersion at 200°C for 3 hours. The adsorbed moisture amount is the amount of moisture adsorbed onto the solid when the solid is exposed to conditions of 90 RH% at 25°C for 1 hour.

[0020] It is preferable that the barium titanate particles are not surface-treated. This makes it easier for the viscosity of the paste to decrease. In particular, if the moisture content of the dispersion is 3% or less, the viscosity of the paste is even more likely to decrease. If the barium titanate is surface-treated with an organic acid-based surface treatment agent such as linoleic acid or oleic acid, the viscosity of the paste may increase. However, as long as the viscosity of the paste does not increase, it is acceptable for the barium titanate particles to be surface-treated with a surface treatment agent.

[0021] It is desirable for the organic solvent to have OH groups. That is, it is desirable for the organic solvent to have high hydrophilicity. As a result, the viscosity of the dispersion or paste tends to decrease. When the organic solvent has OH groups, if the amount of adsorbed water is 5 parts by mass or more per 100 parts by mass of solid content, the viscosity of the dispersion tends to decrease.

[0022] It is preferable for the organic solvent to have at least one of an ester bond, an ether bond, and a ketone group along with an OH group. By doing so, the hydrophilicity of the organic solvent is increased. In particular, high hydrophilicity is obtained by having an ether bond.

[0023] Alternatively, it is preferable for the organic solvent to have a hydrophobic structure along with OH groups. Here, a hydrophobic structure refers to a cyclic structure or a chain structure in which two or more carbon atoms are continuously carbon-carbon bonded from the terminals. As a cyclic structure, a cyclic hydrocarbon group (R6) that is a monovalent substituent from which a hydrogen atom is removed from any carbon atom of a cycloalkane, cycloalkene (cycloolefin), aromatic ring, etc. R6 may be any of a 3-membered ring, a 4-membered ring, a 5-membered ring, a 6-membered ring, a 7-membered ring, etc. The structure of a 6-membered R6 is exemplified in FIG. 1. In FIG. 1, (a) is a 6-membered aromatic ring, (b) is a 6-membered cycloalkene, and (c) is a 6-membered cycloalkane. In the structure of R6, some of the carbon atoms may be substituted with heteroatoms such as oxygen, nitrogen, or sulfur atoms. At this time, depending on the number of bonds that can be formed by the heteroatom, it does not matter if the number of hydrogen atoms bonded to the heteroatom increases or decreases. Additionally, in the structure of R6, R1 to R5 can be selected from hydrophilic groups such as hydrogen, OH, or carboxyl groups, or hydrophobic groups such as methyl, ethyl, isopropyl, or t-butyl groups. R1 to R5 may be the same or different. It is preferable that R1 to R5 consist of four hydrogen groups and one methyl group. This increases the compatibility between the organic solvent and the binder. An organic solvent having a cyclic structure can be represented as R6-R7 (provided that R7 has a structure containing elements such as carbon, hydrogen, nitrogen, and oxygen). It is preferable that the OH group be included in R7. This increases the compatibility between the organic solvent and the binder and the barium titaniumate particles.

[0024] Examples of chain structures include straight-chain structures such as alkyl groups, or branched structures such as isopropyl groups and tert-butyl groups. Organic solvents having a chain structure can be represented by the structural formula R3-CR4R5-CH3. In this structural formula, the methyl group (-CH3) is the terminal. The carbon atom bonded to the terminal methyl group is the second carbon atom from the terminal. In other words, the carbon atom of the methyl group and the carbon atom bonded to the methyl group are continuously connected by carbon-carbon bonds from the terminal. Here, R3, R4, and R5 have structures containing elements such as carbon, hydrogen, nitrogen, and oxygen. R3, R4, and R5 may each be bonded to form a cyclic structure. It is believed that if the organic solvent has a hydrophobic structure, the compatibility between the organic solvent and the binder increases. If the organic solvent possesses a hydrophobic structure and OH groups, the organic solvent increases the compatibility between the binder and the barium titanate particles. Consequently, the paste becomes less likely to aggregate. It is preferable that the number of carbon atoms continuously bonded to carbon-carbon from the ends of the chain structure be five or fewer. This increases the hydrophilicity of the organic solvent. It is more preferable that the number of carbon atoms bonded to carbon-carbon is four or fewer. When the organic solvent has ether bonds, it is preferable that an alkyl group is bonded to the oxygen atom of the ether bond. It is preferable that the number of carbon atoms of this alkyl group be three to five.

[0025] The solubility parameter (SP value) of the organic solvent is preferably 8.5 or higher. If it is 8.5 or higher, the hydrophilicity of the organic solvent increases.

[0026] It is preferable that the boiling point of the organic solvent under atmospheric pressure be 300°C or lower. As a result, the carbon chains of the organic solvent become shorter than those of organic solvents with a boiling point higher than 300°C. Consequently, the viscosity of the dispersion is lowered. Additionally, since the viscosity of the printing paste is also lowered, it is easier for the printing paste to be uniformly coated during printing. It is preferable that the boiling point of the organic solvent under atmospheric pressure be 200 to 300°C. As a result, when coating and drying the paste, the Ni particles and barium titanate particles are dispersed, making it easier for the paste to dry uniformly. Consequently, the sintering delay effect of the Ni particles is enhanced. Furthermore, it becomes less likely for cracks to occur in the MLCC. If the organic solvent with a boiling point of 200 to 300°C has OH groups, it becomes easier to mix the dispersion and the Ni particles. Consequently, the paste becomes less likely to aggregate. Since the paste is less likely to aggregate, it becomes easier for the paste to dry uniformly, thereby improving printability. In terms of boiling point or hydrophobic structure, butylcarbitol is preferred as an organic solvent.

[0027] It is preferable that the viscosity of the organic solvent be 100 mPa·s or less at 25°C under atmospheric pressure. This lowers the viscosity of the dispersion and also lowers the viscosity of the printing paste.

[0028] Next, a method for manufacturing barium titaniumate particles and their dispersion is described.

[0029] First, a mixture A is prepared by mixing a barium hydroxide with an alkyl cellosolve as a solvent (first process). By using a barium hydroxide, counterions do not diffuse into the dielectric layer when the electrode layer is fired. Therefore, the performance of the MLCC is likely to be improved. Since the solvent is an alkyl cellosolve, the viscosity of the dispersion is lowered. In addition, it is difficult for the viscosity of the paste to increase. The water content of the mixture A is preferably 5 mass% or less. As a result, when the titanium alkoxide described later is added, the titanium alkoxide is less likely to undergo hydrolysis. Therefore, the particle size is likely to become smaller. Before the second process described later, the mixture A may be reduced in pressure or heated to reduce the water content of the mixture A to 5 mass% or less.

[0030] Next, titanium alkoxide is added to mixture A to prepare mixture B (second process). It is preferable that the atomic ratio of barium to titanium in mixture B, Ba / Ti, be 0.95 to 1.05. Within this range, it becomes difficult to form crystals other than perovskite structures. The atomic ratio of barium to titanium may be 0.9 to 1.1. It is preferable that the titanium alkoxide be added under a nitrogen atmosphere. This lowers the reaction rate of the titanium alkoxide. Consequently, it is easy to obtain barium titanate particles with small particle size or crystallite diameter.

[0031] The structure of the titanium alkoxide is preferably "Ti(OR)4". Here, R is a hydrocarbon group having 1 to 4 carbon atoms, or a substituted hydrocarbon group in which one or more hydrogen atoms are substituted with a halogen atom. Additionally, R may be the same or different. With such a structure, the crystallinity of the barium titaniumate particles is likely to increase. Specifically, examples include titanium tetramethoxide, titanium tetraethoxide, titanium tetran-propoxide, titanium tetraisopropoxide, titanium tetran-butoxide, titanium tetraisobutoxide, etc.

[0032] Next, water is added to mixture B to prepare mixture C (third process). It is preferable that the amount of water added be an equivalent amount or more in moles relative to the titanium alkoxide. As a result, the amount of titanium alkoxide remaining in mixture C without hydrolysis is reduced. Consequently, the crystallinity of the barium titanate particles is increased.

[0033] Next, mixture C is heated (Process 4). It is preferable to heat at 40°C or higher for 2 to 200 hours. Through this process, aging proceeds, and barium titanate particles are formed in the aged product. If the heating temperature is 40°C or higher, the particle size distribution tends to become uniform, although this varies depending on the gel concentration. Additionally, crystallinity improves. Furthermore, a heating temperature of 120°C or lower is easier to handle industrially. If heated for 2 hours or more, the particle size distribution tends to become uniform. Additionally, crystallinity tends to improve. If the heating time is 200 hours or less, the particle size or crystallite diameter tends to decrease. A heating time of 5 hours or more and 100 hours or less is more preferable.

[0034] The aged product obtained in the fourth process is ultrafiltered or distilled (fifth process). When ultrafiltering or distilling, the water content of the dispersion is adjusted to less than 3% by weight. An organic solvent may be added before ultrafiltering or distilling. If the boiling point of the organic solvent is lower than that of alkyl cellosolve, ultrafiltering is preferred. If it is higher than that of alkyl cellosolve, distillation is preferred. The organic solvent preferably has the characteristics of the organic solvent described in the description of the dispersion above.

[0035] The dispersion prepared by this manufacturing method has a low water content. Consequently, it is difficult for the viscosity of the paste to increase. Furthermore, the particle size and crystallite diameter of the barium titanate particles in the dispersion are small, and the crystallinity is high. Additionally, since the crystal system of the barium titanate particles is close to the cubic system, the sintering delay effect of Ni is enhanced when used in the electrode layer.

[0036] In addition, prior to the fourth process, it is preferable to add a metal salt comprising at least one selected from Group 2, Group 3, lanthanoids, actinoids, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, Group 13, and Group 14. By adding such a metal salt, the sintering delay effect is enhanced. Furthermore, as it is a metal salt, it becomes difficult for crystals other than the perovskite structure to form. Additionally, by adding the metal salt prior to the fourth process, the metal salt is dispersed in the barium titanate gel. Consequently, the sintering delay effect is likely to be enhanced.

[0037] Below, embodiments of the present invention will be described in detail. The preparation conditions for each embodiment and comparative example are listed in Table 1.

[0038] [Example 1]

[0039] <Preparation of Dispersion>

[0040] 50 g of barium hydroxide octahydrate (manufactured by Fujifilm Wako Junyaku Co., Ltd.) and 315 g of 2-methoxyethanol (methylcellosolve) were placed in a beaker and dissolved at 30°C for 20 minutes. The Ba concentration of this solution was 6.0 wt%, and the water content was 6.2 wt%. This solution was placed in a 1 d m³ branch-type flask and distilled using a rotary evaporator to obtain mixture A. The distillation conditions were set at a temperature of 70°C and a reduced pressure of 0.015 MPa for 1 hour. The Ba concentration of mixture A was 16.0 wt%, and the water content was 0.5 wt%.

[0041] In a glove box under a nitrogen gas atmosphere, 56.18 g of tetraisopropoxytitanium (manufactured by Matsumoto Fine Chemical Co., Ltd.: Orgatics (registered trademark) TA-10, Ti concentration 16.88 wt%) was mixed with 170 g of mixture A to prepare mixture B.

[0042] In addition, a mixture of 57.1 g of water and 171.2 g of methanol was added over a period of 1 minute. During addition, the mixture was stirred while maintaining the temperature at 25°C. The resulting hydrate gel was heated to 80°C and aged for 96 hours. The aged product was ultrafiltered to obtain a dispersion containing 40 mass% of barium titanate.

[0043] The dispersion was measured as follows. The measurement results of each example and comparative example are listed in Table 2.

[0044] ≪Measurement of Moisture Content≫

[0045] Measurements were taken using a desktop total moisture meter CA-200 type (manufactured by Mitsubishi Chemical Analytech).

[0046] ≪Measurement of Adsorbed Moisture Content≫

[0047] 30g of the dispersion was dried at 200°C for 3 hours and cooled in a desiccator to obtain a dry powder. The dry powder was left to stand for 1 hour in a constant temperature and humidity chamber (Espect PL-3J) adjusted to 25°C and 90 RH%. The amount of adsorbed moisture was calculated from the weight change before and after this.

[0048] ≪X-ray Diffraction Measurement≫

[0049] The dispersion was dried at 400°C to obtain a powder of barium titaniumate particles. X-ray diffraction measurements were performed on this powder using a RINT-Ultima manufactured by Rigaku. X-ray diffraction measurements were performed in the same manner for the examples and comparative examples described below. In the X-ray diffraction measurements, no X-ray diffraction peaks other than the perovskite structure were observed except for Comparative Example 1.

[0050] ≪Measurement of Viscosity≫

[0051] A binder solution was prepared by dispersing 3 g of ethylcellulose powder in 74 g of terpineol (manufactured by Yasuhara Chemical Co., Ltd.). 4.5 g of this binder solution and 3 g of the dispersion were mixed to obtain a paste for viscosity measurement. Using a rheometer RS3000 (HAAKE), dγ / dt = 0.1 to 1000s -1 Dynamic viscosity measurements were performed in the range of , and dγ / dt=40s -1 The value at that time was defined as the viscosity.

[0052] Evaluation of Printability

[0053] A paste for viscosity measurement was applied to a glass plate and dried at 200°C. The aggregates and smoothness of the dried film were visually inspected, and printability was evaluated.

[0054] ◎: No aggregates, excellent smoothness

[0055] ○: Almost no aggregates, and excellent smoothness

[0056] △: Almost no aggregates, and slight difficulty with smoothness

[0057] ×: Many aggregates are visible or there is difficulty with smoothing

[0058] Preparation of Electrode Paste

[0059] 50 g of dispersion (the amount of barium titanate in the dispersion was 10 g), 40 g of Ni nanoparticles with a particle size of 200 nm (JFE Mineral Co., Ltd.: NFP301SD), and 10 g of ethylcellulose powder were mixed and first dispersed using a Shinki Awatori Rentaro (registered trademark) AR-250. Additionally, an electrode paste was prepared by secondarily dispersing using a 3-axis roller (Inoue Seisakusho: HHC type). The concentration of the electrode paste was 60 wt%. For the examples and comparative examples described below, electrode pastes were prepared in the same manner and measured and evaluated.

[0060] Preparation of Paste for Genome Layers

[0061] 90 g of barium titaniumate (manufactured by Sakai Chemical Co., Ltd.: BT-01, average particle size = 300 nm) and 10 g of ethylcellulose-based powder were added to 56.5 g of terpineol-based solvent and dispersed using an Awatori lentaro. Additionally, a paste for a dielectric layer was prepared by dispersing it secondarily using a triaxial roll.

[0062] Preparation of Multilayer Ceramic Capacitors (MLCC)

[0063] An electrode paste was screen printed onto a barium titanium oxide ceramic sheet (thickness = 4.0 μm). This was dried at 600°C for 1 hour. A dielectric layer paste was screen printed onto this. This was dried at 600°C for 1 hour. These processes were repeated to stack a total of 20 layers. This laminate was reduced at 1200°C for 2 hours under a nitrogen gas atmosphere containing 3% H2. Afterward, it was heated at 1000°C for 3 hours under a nitrogen gas atmosphere.

[0064] ≪Crack Number≫

[0065] The MLCC was vertically cut into a square with sides of 100 µm, and cross-sectional images were taken at 100,000x magnification using a scanning electron microscope (SEM). In the square MLCC with sides of 100 µm, cracks present in each layer were identified and counted using cross-sectional images.

[0066] ≪Assessment of Cohesion≫

[0067] The electrode paste was dropped onto a glass plate, and the presence or absence of aggregates was determined by visual inspection.

[0068] In the following examples and comparative examples, each sample was prepared, measured, and evaluated in the same manner as in Example 1.

[0069] [Example 2]

[0070] A dispersion was obtained in the same manner as in Example 1, except that the mixture of Example 1 was changed to a mixture of 71.3 g of water and 214.0 g of methanol.

[0071] [Example 3]

[0072] A dispersion was obtained in the same manner as in Example 1, except that the mixture of Example 1 was changed to a mixture of 2.46 g of nickel acetate tetrahydrate (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 57.1 g of water, and 171.3 g of methanol.

[0073] [Example 4]

[0074] A dispersion was obtained in the same manner as in Example 1, except that the mixture of Example 1 was changed to a mixture of 0.85 g of magnesium acetate tetrahydrate (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 57.1 g of water, and 171.3 g of methanol.

[0075] [Example 5]

[0076] When dissolving the barium hydroxide octahydrate of Example 1 in 2-methoxyethanol, 1.79 g of tin methoxide (manufactured by Alfa Aesar) was added. Otherwise, the dispersion was prepared in the same manner as in Example 1.

[0077] [Example 6]

[0078] When dissolving the barium hydroxide octahydrate of Example 1 in 2-methoxyethanol, 2.02 g of calcium methoxide (manufactured by Strem Chemicals) was added. A dispersion was obtained in the same manner as in Example 1, except that 178 g of this solution was used.

[0079] [Example 7]

[0080] When dissolving the barium hydroxide octahydrate of Example 1 in 2-methoxyethanol, 0.67 g of tantalum methoxide (manufactured by Strem Chemicals) was added. Otherwise, a dispersion was obtained in the same manner as in Example 1.

[0081] [Example 8]

[0082] A dispersion was obtained in the same manner as in Example 1, except that the mixture of Example 1 was changed to a mixture of 0.92 g of nickel hydroxide hydrate (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 57.1 g of water, and 171.2 g of methanol.

[0083] [Example 9]

[0084] When dissolving the barium hydroxide octahydrate of Example 1 in 2-methoxyethanol, 0.67 g of dysprosium isopropoxide (manufactured by Fujifilm Wako Chemical Co., Ltd.) was added. Otherwise, a dispersion was obtained in the same manner as in Example 1.

[0085] [Example 10]

[0086] To mixture B obtained in Example 1, a hydrolysis solution prepared by mixing 57.1 g of water and 171.3 g of methanol was added over a period of 1 minute while maintaining the temperature at 25°C under stirring. A hydrate gel was obtained. The hydrate gel was heated to 80°C and aged for 96 hours. Ethanol was mixed with the aged product, and ultrafiltration was performed to obtain a dispersion containing 40 mass% of barium titanate.

[0087] [Example 11]

[0088] Mixture B was prepared in the same manner as in Example 1, except that the weight of Mixture A was changed to 178 g. 70 g of butyl carbitol (manufactured by Kanto Chemical Co., Ltd.) was mixed into the aged product, and a dispersion was obtained in the same manner as in Example 1, except that solvent exchange was performed using a rotary evaporator instead of ultrafiltration. The solvent exchange was carried out under conditions of a temperature of 70°C, a reduced pressure of 0.015 MPa, and for 1 hour.

[0089] [Example 12]

[0090] A dispersion was obtained in the same manner as in Example 11, except that the weight of mixture A was changed to 170g.

[0091] [Example 13]

[0092] A dispersion was obtained in the same manner as in Example 12, except that the solution for hydrolysis was changed to a solution of 2.46 g of nickel acetate tetrahydrate (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 57.1 g of water, and 171.3 g of methanol.

[0093] [Example 14]

[0094] A dispersion was obtained in the same manner as in Example 12, except that the weight of mixture A was changed to 168g and 70g of terpineol and 3.5g of linoleic acid (manufactured by Fujifilm Wako Junyaku Co., Ltd.) were mixed into the aged product instead of butylcarbitol.

[0095] [Example 15]

[0096] 3.5 g of linoleic acid was added to the aged product obtained in Example 11 and stirred at 50°C for 15 hours. 70 g of butyl carbitol was added to this and distilled using a rotary evaporator to obtain a dispersion. The distillation conditions were a temperature of 70°C, a reduced pressure of 0.015 MPa, and 1 hour.

[0097] [Example 16]

[0098] 70g of terpineol was added to the aged product obtained in Example 10. Distillation was performed using a rotary evaporator under conditions of a temperature of 70℃, a reduced pressure of 0.015MPa, and for 1 hour.

[0099] [Example 17]

[0100] 70g of triethanolamine was added to the aged product obtained in Example 10. Distillation was performed using a rotary evaporator under conditions of a temperature of 70℃, a reduced pressure of 0.015MPa, and for 1 hour.

[0101] [Comparative Example 1]

[0102] A dispersion was obtained in the same manner as in Example 1, except that the weight of the barium hydroxide solution was changed to 204g.

[0103] [Comparative Example 2]

[0104] Barium carbonate (manufactured by Fujifilm Wako Junyaku Co., Ltd.) and titanium oxide powder (manufactured by Ishihara Sangyo Co., Ltd.) were weighed to achieve a Ba / Ti atomic ratio of 1.01 and mixed using a ball mill. The mixed powder was calcined in air at 900°C, and the calcined powder was further crushed using a mortar and pestle. The crushed calcined powder was mixed with 2-methoxyethanol and dispersed to achieve a solid content of 40%.

[0105]

[0106]

Claims

Claim 1 A dispersion comprising barium titaniumate particles having a perovskite structure and an organic solvent having a boiling point of 200 to 300°C, wherein the atomic ratio of barium to titanium Ba / Ti of the barium titaniumate particles is 0.9 to 1.1, the crystallite diameter of the barium titaniumate particles is 5 to 25 nm, and the water content of the dispersion is less than 3 weight%. Claim 2 A dispersion according to claim 1, characterized in that the organic solvent has OH groups, and when the solid obtained by drying the dispersion at 200°C for 3 hours is exposed to conditions of 25°C and 90 RH% for 1 hour, the amount of water adsorbed to the solid is 5 parts by mass or more per 100 parts by mass of the solid. Claim 3 A dispersion according to claim 2, characterized in that the organic solvent has a cyclic structure or a chain structure in which two or more carbon atoms are continuously carbon-carbon bonded from the ends. Claim 4 A dispersion according to paragraph 3, characterized in that the organic solvent has ether bonds. Claim 5 A method for preparing a dispersion of barium titanate particles, characterized by sequentially comprising: a first step of mixing barium hydroxide and alkyl cellosolve to prepare a mixture; a second step of adding titanium alkoxide to the mixture such that the atomic ratio of barium to titanium Ba / Ti is in the range of 0.9 to 1.1; a third step of adding water to the mixture; a fourth step of heating the mixture; and a fifth step of adding an organic solvent having a boiling point of 200 to 300°C to the mixture and then adjusting the water content to less than 3 weight%. Claim 6 A method for manufacturing a multilayer ceramic capacitor characterized by including a process of preparing an electrode paste using a dispersion of barium titaniumate particles described in claim 1. Claim 7 delete Claim 8 delete

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