JP2005075700A - Method for manufacturing composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a composition which is based on an improved hydrothermal synthesis method and can yield the composition containing an ABO<SB>3</SB>compound which consists of uniform fine spherical particles having an average diameter of ≤1 μm, preferably 0.01 to 0.5 μm, and excellent crystallinity and in which the A/B ratio can be arbitrarily controlled and only few nanometer size pores are included in each crystal particle. <P>SOLUTION: The composition containing an perovskite type compound is manufactured by the method including: a first process for dehydrating a hydrated oxide of at least one kind of group B elements selected from Ti, Zr, Hf and Sn at a temperature of 80 to 300°C in the presence of an aqueous medium; and a second process for heating the reaction product obtained in the first process and a hydroxide of at least one group A element selected from Ba, Sr, Ca, Mg and Pb at a temperature of 100 to 300°C in the presence of an aqueous medium. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention comprises uniform spherical particles having an average particle size of 1 μm or less, preferably 0.01 to 0.5 μm, high crystallinity, and the A / B ratio is arbitrarily controlled, In addition, the present invention relates to a method for producing a composition containing a perovskite type compound (hereinafter referred to as ABO ₃ compound) having few internal vacancies in such particles. Such an ABO ₃ compound obtained according to the present invention provides an unprecedented excellent sintered body of ABO ₃ compound, for example, a thin-layer sintered body free from layer defects of barium titanate.

The ABO ₃ compound is a general term for compounds having a crystal structure similar to that of calcium titanate ore (perovskite). Such a compound has excellent dielectric properties by being molded and then sintered. Ceramics having piezoelectricity and semiconductivity (hereinafter referred to as dielectric ceramics) are provided. Such sintered bodies are widely used today in electronic devices such as communication devices and computers as capacitors, filters, ignition elements, thermistors, and the like.

In recent years, electronic devices have become smaller and higher in performance, and electronic component parts are also manufactured in the same way, with the objective of reducing the size and performance, manufacturing processes such as dielectric ceramic compounding technology, molding technology, and sintering technology. Various improvements have been made. However, such improvements in the manufacturing process have almost reached its limit, and it is necessary to improve the material in order to obtain a dielectric ceramic superior to the present situation. That is, there is a demand for an ABO ₃ compound having an average particle size of 1 μm or less, preferably 0.5 μm or less and having a uniform spherical shape and good dispersibility.

The reason why an ABO ₃ compound having such characteristics is desired is that if the particle size is small, the surface energy is high, and if the shape is spherical and the particle size distribution is uniform, the packing property during molding is improved. Such an ABO ₃ compound has remarkably improved sinterability, and can provide a dense and strong dielectric ceramic by sintering at a lower temperature. Furthermore, in order to realize a multilayer ceramic capacitor having a thin layer and multiple layers, a ceramic green sheet having a thickness of 5 μm or less is required. In this case, the average particle size is 1 μm or less, There is a demand for an ABO ₃ compound having a uniform spherical shape of 0.5 μm and good dispersibility.

Conventionally, ABO ₃ compounds, typically barium titanate, are mixed with barium carbonate and titanium oxide, calcined at a temperature of 1000 ° C. or higher, then wet pulverized, filtered, dried, and classified. It is manufactured by a so-called solid phase method. According to such a solid phase method, in order to complete the solid phase reaction between barium carbonate and titanium oxide, the mixture needs to be calcined at a high temperature for a sufficient time. However, if calcination is performed at such a high temperature for a long time, particle growth during that time cannot be avoided, and as a result, it is difficult to control the particle size of the obtained barium titanate particles to 1 μm or less. In addition, when the obtained barium titanate is used for various purposes, it is pulverized after being made into a sintered body, so that the particle size distribution is not uniform and the shape is also suitable for dispersion. It is difficult (see Non-Patent Document 1).

  In order to solve such problems, it has been proposed to produce barium titanate by a wet method. Examples of the wet method include an alkoxide method, a coprecipitation method, an oxalic acid method, a hydrothermal synthesis method, and the like, but all methods still have important problems.

  For example, in the alkoxide method, barium alkoxide and titanium alkoxide are mixed and hydrolyzed, or titanium alkoxide and barium hydroxide are reacted to obtain barium titanate, but the alkoxide raw material used is only expensive. In addition, since it is necessary to recover the by-produced alcohol, there is a problem in industrial implementation (see Patent Document 1).

  According to the coprecipitation method, it is possible to obtain a barium titanate powder that is relatively inexpensive and has good sinterability. According to an example of this coprecipitation method, for example, if a water-soluble barium salt and a hydrolysis product of a titanium compound are heated in the presence of a strong alkali and reacted, barium titanate can be obtained. However, in the case of such a method, it is difficult to remove the alkali used in the above reaction even if the obtained reaction product is washed, and alkali is inevitable in the obtained barium titanate powder. (For example, refer to Patent Document 2).

  In the oxalic acid method, for example, titanium tetrachloride, barium chloride, and oxalic acid are reacted in water to form barium titanyl oxalate, which is thermally decomposed to obtain barium titanate. When this method is used, a high-purity product of titanium tetrachloride or barium chloride used as a raw material can be obtained relatively easily. Therefore, there is an advantage that high-purity barium titanate can be easily obtained. However, the barium titanyl oxalate obtained as a precipitate by this method is a considerably large aggregate, and the skeleton of the aggregate remains during calcination, so that coarse particles are easily generated. In addition, when the obtained barium titanate powder is sintered into a barium titanate ceramic, there is a problem that the dielectric loss is high (for example, see Patent Document 3).

  Further, as a method for producing barium titanate, a method of hydrothermally treating a hydroxide of barium hydroxide and titanium or a mixture of oxides is known as a hydrothermal synthesis method. According to this method, uniform and fine barium titanate having particularly good dispersibility can be obtained. Thus, barium titanate by hydrothermal synthesis is preferably used for thinning and multilayering of multilayer ceramic capacitors. It is said that it can be done.

  However, in the hydrothermal synthesis method, since the reaction between barium hydroxide and titanium hydroxide or oxide does not proceed 100%, unreacted titanium components are mixed in the barium titanate obtained by the reaction as a solid. On the other hand, unreacted barium hydroxide is dissolved in the resulting reaction mixture. Therefore, after the reaction, the obtained reaction mixture is filtered, washed with water, and the obtained barium titanate is separated from the reaction mixture as a solid content, so that the water-soluble barium component is removed from the obtained barium titanate. Therefore, the obtained barium titanate contains an excess of a titanium component. Therefore, even when such a barium titanate powder is sintered, only a sintered body having an excessive titanium component can be obtained. Moreover, in the production of barium titanate by hydrothermal synthesis, the reaction rate of the raw material varies slightly from reaction to reaction, so that it cannot be strictly controlled to a predetermined Ba / Ti ratio for use as an electronic material. Therefore, they are not suitable as raw materials for dielectric ceramics (see, for example, Patent Document 4 and Non-Patent Document 3).

Therefore, conventionally, in order to solve such a problem in the production of the ABO ₃ compound by the hydrothermal synthesis method, the A / B ratio is controlled by insolubilizing the A group element dissolved in the aqueous medium after the hydrothermal reaction. A method has been proposed and put to practical use as a method for producing a dielectric ceramic material (see Patent Document 5).

Thus, although the problem of controlling the A / B ratio has been solved in the production of the ABO ₃ compound by the hydrothermal synthesis method, the barium titanate produced by the hydrothermal synthesis method is further reduced by the oxygen of the particles. There is a new problem that the lattice contains a hydroxyl group. That is, it is known that when such barium titanate is heated to a temperature of 100 to 600 ° C., a dehydration reaction takes place, and nanometer (nm) size pores are formed in the particles. The voids formed in the barium titanate particles in this way cause cracks and delamination when barium titanate is used as a thin-layer sintered body, further thinning the multilayer ceramic capacitor Since multilayering is hindered, the solution is required (for example, see Non-Patent Document 4).
US Pat. No. 5,087,437 JP 59-39726 A US Pat. No. 2,758,911 U.S. Pat. No. 2,193,563 JP 61-31345 A Sasaki, Kyoichi, “Production and process of barium titanate and its composite particles”, Journal of Powder Engineering, Powder Engineering Society, 1997, Vol. 11, No. 11, pp. 862-874 Yoshiko Suwa et al., "Production of BaO-TiO2 compounds by alkoxide coprecipitation", powder and powder metallurgy, 1978, Vol. 25, No. 5, pp. 164-167 Teruichiro Kubo, “Wet synthesis method of barium titanate (BaTiO3),“ Industrial Chemical Journal ”, 1968, Vol. 71, No. 1, pp. 114-118 DFK Hennings et al., “Defect chemistry and microstructure of barium titanate by hydrothermal synthesis”, Journal of American Ceramic Society (J. Am. Ceram. Soc.), 2001 Year, Vol. 84, No. 1, pp. 179-182

As described above, conventionally, ABO ₃ compounds represented by barium titanate cannot adequately meet the demands for downsizing and high performance of electronic parts such as capacitors, filters, and thermistors. There is. Also, in the hydrothermal synthesis method, which is said to be an excellent production method in that uniform fine spherical particles with good dispersibility can be obtained, as described above, nanometer-sized particles are formed in the particles by dehydration during heating. There is a problem in that when voids are generated, and when barium titanate having voids in the particles is used for manufacturing a multilayer ceramic capacitor, cracks and delamination are caused.

The present invention has been made to solve the above-mentioned problems in the production of ABO ₃ compounds typified by barium titanate, and has an average particle size of 1 μm or less, preferably 0.01 to 0. A composition containing an ABO ₃ compound having a high crystallinity composed of uniform fine spherical particles of 5 μm, an arbitrarily controlled A / B ratio, and a small number of nanometer-sized vacancies in the crystal particles It is an object of the present invention to provide a method for producing the above composition by an improved hydrothermal synthesis method capable of producing a product. Thus, the ABO ₃ compound having few vacancies in the crystal grains can be advantageously used for the production of the multilayer ceramic capacitor.

According to the present invention,
A first step of dehydrating the hydrated oxide by heating a hydrated oxide of at least one group B element selected from Ti, Zr, Hf and Sn in the presence of an aqueous medium at a temperature in the range of 80 to 300 ° C .; ,
The reaction product obtained in the first step and a hydroxide of at least one group A element selected from Ba, Sr, Ca, Mg, and Pb in the presence of an aqueous medium, a temperature in the range of 100 to 300 ° C. And a second step of heating at a temperature, a method for producing a composition containing a perovskite type compound is provided.

In accordance with the present invention, the hydrous oxide of group B element is heated at a temperature in the range of 80 to 300 ° C. in the presence of an aqueous medium and dehydrated to obtain a reaction product. The composition containing the ABO ₃ compound obtained by hydrothermally treating with a hydroxide in the presence of an aqueous medium has an average particle size of 1 μm or less, preferably in the range of 0.01 to 0.5 μm. The ABO ₃ compound contained in this composition is a uniform spherical particle, has high crystallinity, has an arbitrarily controlled A / B ratio, and has nanometer-sized pores in the crystal particle. The number is usually 10 or less per 100 particles. Therefore, such a composition is excellent in sinterability, and when sintered, gives a very dense dielectric ceramic having excellent dielectric properties, piezoelectric properties, semiconductivity and the like.

  In the method for producing a composition containing a perovskite type compound according to the present invention, the first step is a step of using a water-containing oxide of at least one group B element selected from Ti, Zr, Hf and Sn as an aqueous medium, preferably water. In the presence, it is heated at a temperature in the range of 80 to 300 ° C. to dehydrate the hydrated oxide to obtain a reaction product having higher crystallinity as fine particles. The reaction product is mainly composed of an oxide of a corresponding group B element.

  In general, the hydrated oxide of the group B element is an amorphous solid, but by heating and dehydrating it, an oxide with higher crystallinity can be obtained as fine particles. That is, by heating and dehydrating the hydrous oxide of the group B element, the primary particle diameter is usually in the range of 0.005 to 0.4 μm, preferably 0.01 to 0.2 μm. A reaction product that is a product can be obtained.

  In the first step, the temperature at which the hydrous oxide of the group B element is heated in the presence of the aqueous medium ranges from 80 to 300 ° C. Under normal pressure, it can be heated to a temperature in the range of 80 ° C. to the boiling temperature of the aqueous medium (about 100 ° C.). According to the hydrothermal reaction, it is heated from about 100 ° C. to the critical temperature of the aqueous medium. be able to.

  In the present invention, when the heating temperature in the presence of the aqueous medium of the hydrous oxide of the group B element is lower than 80 ° C., it is difficult for the dehydration reaction to proceed. On the other hand, the higher the heating temperature, the easier the dehydration reaction proceeds. In addition, the particle size of the reaction product obtained tends to increase. However, when the heating temperature exceeds 300 ° C., there are practical problems from the viewpoint of the apparatus, such as the need to use silver or the like as the material of the reactor. In particular, according to the present invention, the heating temperature in the presence of the aqueous medium of the hydrous oxide of the group B element is preferably in the range of 100 to 300 ° C.

  Furthermore, according to the present invention, in the first step, when the hydrous oxide of the group B element is heated in the presence of the aqueous medium, the dehydration reaction of the group B element and the refinement of the reaction product are promoted. In addition, the hydrous oxide of the group B element may be heated in the presence of an acid or a base. Here, an inorganic acid or an organic acid can be used as the acid, and hydrochloric acid or nitric acid is preferably used as the inorganic acid. On the other hand, as the organic acid, an organic polyvalent carboxylic acid or an organic oxypolyvalent carboxylic acid is preferably used. Among them, an organic polyvalent carboxylic acid having 2 to 6 carbon atoms or an organic oxypolyvalent carboxylic acid is preferably used. It is done. Specific examples include oxalic acid, tartaric acid, and citric acid. In addition, alkali metal salts and alkaline earth metal salts of these organic polyvalent carboxylic acids and organic oxypolyvalent carboxylic acids are also preferably used.

  On the other hand, examples of the base include inorganic bases such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and particularly organic bases such as alkali metal hydroxides and amines.

  In the first step, the hydrated oxide of the group B element used as a raw material may be a commercially available product as it is, or may be appropriately prepared. For example, a method in which a base such as an alkali is allowed to act on a salt of the group B element, a method in which the salt of the group B element is heated and hydrolyzed, and an ammonia generating source such as urea is added to the salt of the group B element, followed by heating. In the present invention, the hydrous oxide of the B group element is particularly limited in its preparation method. Is not to be done.

  Next, according to the present invention, as the second step, the reaction product of the group B element obtained as described above and the hydroxide of the group A element are heated in the presence of an aqueous medium, preferably water. And hydrothermal reaction. The reaction temperature of this hydrothermal reaction is from 100 ° C. to the critical temperature of the aqueous medium, but when the reaction temperature is lower than 100 ° C., the reaction between the group A element and the group B element is insufficient, When the temperature exceeds ° C., there is a problem that it is necessary to use a special apparatus as described above, and therefore, the temperature is preferably in the range of 100 to 300 ° C.

  As the hydroxide of the group A element used in the second step, a commercially available product may be used as it is, or may be appropriately prepared. For example, a method in which a base such as an alkali is allowed to act on a salt of a group A element, a method in which an oxide of a group A element is reacted with water to hydrolyze, or a method in which water is reacted with an alkoxide of a group A element. However, in the present invention, the hydroxide of the group A element is not limited at all in the preparation method.

According to the present invention, in order to promote the refinement and crystallization of the ABO ₃ compound obtained in the second step, as in the first step, the hydrothermal reaction is performed in the presence of the acid or base as described above. You may go.

In the second step, the produced ABO ₃ compound and the unreacted group B element compound are present as solids in the reaction mixture after the hydrothermal reaction, while the unreacted group A element hydroxide is Part or all is dissolved in the aqueous medium, and thus the obtained ABO ₃ compound does not have an A / B ratio as it is in the charged composition. Therefore, in the present invention, after the completion of the hydrothermal reaction in the second step, if necessary, the A / B ratio is adjusted so that the composition containing the finally obtained ABO ₃ compound has a desired A / B ratio. It is preferable to control the B ratio. Thus, if the composition containing the ABO ₃ compound having a desired A / B ratio is sintered, a sintered body of the ABO ₃ compound having the desired A / B ratio is finally obtained. Can do.

Such control of the A / B ratio can be performed by a conventionally known method. For example, after the hydrothermal reaction, the resulting reaction mixture is filtered and washed with water to remove the compound of group A element dissolved in the aqueous medium from the reaction mixture, and then the reaction product (solid) obtained A / B ratio is analyzed. Then, an ABO having a desired A / B ratio can be obtained by adding a compound of a group A element as an additive for controlling the A / B ratio to the reaction product so as to obtain a desired A / B ratio. A composition containing _three compounds can be obtained, and if such a composition is sintered, a sintered body having a desired A / B ratio can be obtained.

Here, as the compound of the group A element added as an additive to the obtained reaction product, the solubility in an aqueous medium is low, and a composition containing the ABO ₃ compound added with the additive as described above is baked. When the additive is thermally decomposed, no additives other than the group A element remain in the sintered body, such as carbonates, organic acid salts, oxides, and so on. When a composition containing an ABO ₃ compound to which an additive has been added is sintered, the additive is thermally decomposed, and even if a substance other than the group A element remains in the sintered body, the obtained sintering The thing which does not impair the characteristic of a body, for example, a silicate etc. can be mentioned.

  However, a water-soluble group A element compound can also be used as an additive for controlling the A / B ratio described above. When such a water-soluble group A element compound is used as an additive for controlling the A / B ratio, the required amount is added to the reaction mixture obtained by the hydrothermal reaction, and then the reaction mixture is evaporated to dryness. Just harden.

  In addition, as an additive for controlling the A / B ratio other than the above, an insolubilizing agent for insolubilizing an unreacted group A element compound dissolved in the obtained reaction mixture may be used. Examples of such insolubilizing agents include carbon dioxide, carbonate compounds such as sodium carbonate and ammonium carbonate, alkali metal salts of carboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, silicates, silica -Aluminum-based inorganic ion exchange resins can be listed.

Such an insolubilizing agent is added to the reaction mixture in an amount necessary to insolubilize the group A element dissolved in the obtained reaction mixture after the hydrothermal reaction, and after insolubilizing the group A element, filtration is performed. If washed with water, a composition containing an ABO ₃ compound having a required A / B ratio can be obtained. If such a composition is sintered, a sintered body having a desired A / B ratio can be obtained. Can be obtained.

According to the present invention, after the completion of the hydrothermal reaction in the second step, the A / B ratio of the composition containing the finally obtained ABO ₃ compound is accurately set to 1. The A / B ratio can be an arbitrary value as well as 00.

As described above, according to the present invention, in the reaction mixture obtained by the hydrothermal reaction, in addition to the produced ABO ₃ compound, an unreacted group B element compound is present as a solid, while the unreacted compound is present. Part or all of the hydroxide of the group A element is dissolved in the aqueous medium. Further, as described above, when the A / B ratio is adjusted, various kinds of additives based on the additives and insolubilizing agents are used. These compounds coexist with the produced ABO ₃ compound. Accordingly, what is obtained by the method of the present invention is a composition containing an ABO ₃ compound.

According to the present invention, the composition containing the ABO ₃ compound obtained in the second step, if necessary, further, as a third step, may be heat-treated at a temperature in the range of 100 to 1200 ° C.. Thus, by heat-treating the above composition, the reaction between the unreacted group A element and group B element in the obtained composition can be advanced, and the crystallinity of the resulting ABO ₃ compound can be increased. . Further, if necessary, the particle size of the obtained ABO ₃ compound can be further increased. If the heat-treated composition is pulverized and then sintered, a denser sintered body can be obtained.

In general, when producing a sintered body of a composition containing an ABO ₃ compound, for example, to adjust the sinterability of the composition and the electrical characteristics of the obtained sintered body, for example, B, Bi, alkali metal (For example, Li, K, Na, etc.), rare earth elements (eg, Y, Dy, Er, Ho, etc.), transition metals (eg, Mn, Fe, Co, Nb, etc.), compounds such as Si, Al, etc. are additives. It is used as. Also in the present invention, such an additive may be contained in the composition, and the obtained composition may be sintered. Such an additive may be added either after the first step, the second step, or after the end of the second step.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the following, among the particles of the obtained composition, the number of particles having pores is 5-100,000 times, a transmission electron micrograph of the particles is taken, 300 particles are visually observed, The number of particles having pores was counted and converted per 100 particles.

Example 1
While maintaining 94.9 g of titanium tetrachloride (0.5 mol as titanium) at 50 ° C., this was added to 1300 mL of ion-exchanged water with stirring to prepare an aqueous solution of titanium tetrachloride. To this titanium tetrachloride aqueous solution, 800 g of a 10.0 wt% sodium hydroxide aqueous solution was added over 30 minutes to obtain a titanium hydroxide slurry. The obtained titanium hydroxide was washed with water, filtered, adjusted to a 2.0 mol / L concentration slurry, and then reacted at 80 ° C. for 10 hours with stirring (first step).

  A portion of the titanium oxide slurry thus obtained was sampled and examined by X-ray diffraction. As a result, it was a mixture of anatase and brookite crystalline titanium oxide. Moreover, when measured with the electron microscope, the average particle diameter of the obtained titanium oxide was 0.02 micrometer.

The total amount of the obtained titanium oxide slurry was collected by filtration, put into a polytetrafluoroethylene beaker, and further 157.7 g of barium hydroxide octahydrate (Ba (OH) ₂ .8H ₂ O) under a nitrogen atmosphere ( 0.5 mol) as Ba was added and the mixture was hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTiO ₃ ). The slurry was charged into a 1 L autoclave together with the polytetrafluoroethylene beaker, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours.

After the reaction, carbon dioxide gas was blown into the resulting slurry until the pH became 6.5, then washed with water until no chlorine was detected, filtered, dried at 110 ° C., and a composition containing an ABO ₃ compound. A product (hereinafter referred to as a composition) was obtained (second step).

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure. As a result of observation with an electron microscope, the average particle diameter was 0.05 μm, and the ratio of particles having nanometer-sized vacancies was 7 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 21 m ² / g.

Example 2
In the same manner as in Example 1, a titanium tetrachloride aqueous solution was prepared, and a titanium hydroxide slurry was obtained therefrom. The obtained titanium hydroxide was filtered and washed with water to prepare a slurry having a concentration of 1.5 mol / L. Then, the whole amount was put into a polytetrafluoroethylene beaker and charged into a 1 L-volume autoclave. The hydrothermal reaction was performed at 150 ° C. for 5 hours (first step).

  When a part of the obtained titanium oxide slurry was sampled and examined by X-ray diffraction, it was a mixture of anatase and brookite crystalline titanium oxide. Moreover, when measured with the electron microscope, the average primary particle diameter of the obtained titanium oxide was 0.02 micrometer.

Under a nitrogen atmosphere, 315.4 g of barium hydroxide octahydrate was added to the obtained titanium oxide slurry and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTiO ₃ ). This was again charged into a 1 L autoclave, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours.

  After the reaction, acetic acid was added to the obtained reaction mixture to adjust the pH of the reaction mixture to 5, and the slurry was washed with water and collected by filtration. When barium in the obtained total filtrate was analyzed by ICP (inductively coupled radio frequency plasma) method, the reaction rate was 0.985. Here, reaction rate = (number of moles of charged barium−number of moles of barium in filtrate) / number of moles of charged barium).

Pure water is added to the reaction product thus filtered, and the slurry is again slurried and washed with water until chlorine is no longer detected. Then, 1.48 g of fine barium carbonate manufactured by Sakai Chemical Industry Co., Ltd. is added, and the homogenizer is added. To fully disperse. Thereafter, the solid content was collected by filtration and dried at 110 ° C. to obtain a composition containing the ABO ₃ compound (hereinafter referred to as “composition”) (second step).

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure, like the composition according to Example 1. As a result of observation by an electron microscope, the average particle diameter was 0.06 μm, and the ratio of particles having nanometer-sized vacancies was 8 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 19 m ² / g.

Example 3
In the same manner as in Example 1, a titanium tetrachloride aqueous solution was prepared, and a titanium hydroxide slurry was obtained therefrom. The obtained titanium hydroxide was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.0 mol / L. Then, the whole amount was put into a polytetrafluoroethylene beaker, and lithium hydroxide (LiOH) 1 was added thereto. .19 g was added. This was charged in a 1 L autoclave and subjected to a hydrothermal reaction at 150 ° C. for 5 hours with stirring (first step).

  When a part of the obtained titanium oxide slurry was sampled and examined by X-ray diffraction, as shown in FIG. 1, it was a mixture of anatase and brookite crystalline titanium oxide. Moreover, when it measured with the electron microscope, as shown in FIG. 2, the average particle diameter of the obtained titanium oxide was 0.03 micrometer.

Under a nitrogen atmosphere, 315.4 g of barium hydroxide octahydrate was added to the obtained titanium oxide slurry and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTiO ₃ ). This was again charged into a 1 L autoclave, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours. After the reaction, the resulting slurry was washed with water and collected by filtration. When barium in the obtained total filtrate was analyzed by ICP method, the reaction rate was 0.980.

Therefore, pure water was added to the filtered reaction product, and the slurry was again slurried and washed with water until chlorine was no longer detected. Then, 1.97 g of fine barium carbonate manufactured by Sakai Chemical Industry Co., Ltd. was added, and the mixture was homogenized. Sufficiently dispersed. Thereafter, the solid content was collected by filtration and dried at 110 ° C. to obtain a composition containing the ABO ₃ compound (hereinafter referred to as “composition”) (second step).

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure as shown in FIG. As a result of observation by an electron microscope, the average particle diameter was 0.04 μm, and the ratio of particles having nanometer-sized vacancies was 5 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 25 m ² / g.

Example 4
In the same manner as in Example 1, a titanium tetrachloride aqueous solution was prepared, and a titanium hydroxide slurry was obtained therefrom. The obtained titanium hydroxide was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.0 mol / L. Then, the whole amount was put into a polytetrafluoroethylene beaker, and 9.60 g of citric acid was added thereto. It was. This was charged in a 1 L autoclave and subjected to a hydrothermal reaction at 150 ° C. for 5 hours with stirring (first step).

  When a part of the obtained titanium oxide slurry was sampled and examined by X-ray diffraction, it was a mixture of anatase and brookite crystalline titanium oxide. Moreover, when measured with the electron microscope, the average primary particle diameter of the obtained titanium oxide was 0.02 micrometer.

Under a nitrogen atmosphere, 315.5 g of barium hydroxide octahydrate was added to the obtained titanium oxide slurry and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTiO ₃ ). This was again charged into a 1 L autoclave, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours. After the reaction, the resulting slurry was washed with water and collected by filtration. When barium in the total filtrate obtained was analyzed by the ICP method, the reaction rate was 0.997.

Therefore, ion-exchanged water was added to the reaction product collected by filtration, and the slurry was again slurried and washed with water until chlorine was not detected. Then, 2.27 g of fine barium carbonate manufactured by Sakai Chemical Industry Co., Ltd. was added, and the homogenizer was added. To fully disperse. Thereafter, the solid content was collected by filtration and dried at 110 ° C. to obtain a composition containing the ABO ₃ compound (hereinafter referred to as “composition”) (second step).

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure, like the composition according to Example 1. As a result of observation with an electron microscope, the average particle diameter was 0.06 μm, and the ratio of particles having nanometer-sized pores was 4 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.02. The BET specific surface area was 21 m ² / g.

Example 5
In a nitrogen atmosphere, 142.17 g of titanium isopropoxide (0.5 mol as titanium) was dissolved in 300 mL of isopropyl alcohol, and 70 mL of ion-exchanged water was added to the resulting solution over 60 minutes with stirring. A slurry was obtained. The obtained titanium hydroxide was washed with water, filtered, added water, adjusted to a 2.0 mol / L concentration slurry, and then heated at 80 ° C. for 10 hours with stirring (first step).

  When a part of the obtained titanium oxide slurry was sampled and examined by X-ray diffraction, it was anatase crystalline titanium oxide. Moreover, when measured with the electron microscope, the average particle diameter of the obtained titanium oxide was 0.01 micrometer.

The total amount of the obtained titanium oxide slurry is collected by filtration and placed in a polytetrafluoroethylene beaker. Further, 111.8 g of barium isopropoxide is added to the beaker under a nitrogen atmosphere, and the slurry is added to a slurry concentration of 1.0. adjusted to moles / L (BaTiO ₃ conversion). This was charged into a 1 L autoclave, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours. After the reaction, carbon dioxide gas was blown into the obtained slurry until pH 5.6, and then water was washed until chlorine was not detected, followed by filtration and drying at 110 ° C. (second step).

In this way, after the heat treatment of the composition obtained in the second step at about 1000 ° C. in an electric furnace, and wet pulverized in a nylon pot mill using zirconia balls, a composition containing ABO ₃ compound ( Hereinafter referred to as a composition). As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a tetragonal perovskite structure. As a result of observation with an electron microscope, the average particle diameter was 0.4 μm, and the ratio of particles having nanometer-sized pores was 6 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 2.8 m ² / g.

Example 6
While maintaining 94.9 g of titanium tetrachloride (0.5 mol as titanium) at 50 ° C., 1300 mL of ion-exchanged water was added with stirring to prepare a titanium tetrachloride aqueous solution. To this titanium tetrachloride aqueous solution, 0.061 g of manganese nitrate (Mn (NO ₃ ) ₂ .6H ₂ O) was added, and further 800 g of 10.0 wt% sodium hydroxide aqueous solution was added over 30 minutes. A titanium hydroxide slurry was obtained. The titanium hydroxide slurry containing manganese was washed with water, filtered, and hydrated to obtain a slurry having a concentration of 2.0 mol / L, and then heated to 80 ° C. with stirring and reacted for 10 hours (No. 1). One step). The titanium oxide containing manganese thus obtained was measured with an electron microscope and found to have an average particle size of 0.02 μm. Hereinafter, in the same manner as in Example 1, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure. Further, as a result of observation with an electron microscope, the ratio of particles having an average particle diameter of 0.05 μm and having nanometer-sized pores was 7 out of 100 particles. The manganese content by ICP analysis was 0.01% by weight. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 21 m ² / g.

Example 7
The composition obtained in Example 1 was calcined at 900 ° C. in an electric furnace, then wet-pulverized with a planetary ball mill using ion-exchanged water and zirconia beads, and a composition containing an ABO ₃ compound (hereinafter referred to as “the ABO ₃ compound”). A composition).

  As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a tetragonal perovskite structure as shown in FIG. As a result of observation by an electron microscope, the average particle diameter was 0.2 μm, and the ratio of particles having nanometer-sized pores was 7 out of 100 particles.

Example 8
A titanium tetrachloride aqueous solution was prepared in the same manner as in Example 1, and 503 mL of a 5.0 wt% aqueous ammonia solution was added to the titanium tetrachloride aqueous solution over 30 minutes to obtain a titanium hydroxide slurry. The obtained titanium hydroxide was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.5 mol / L. Then, the entire amount was put into a polytetrafluoroethylene beaker, and this was charged into a 1 L capacity autoclave. Then, a hydrothermal reaction was carried out at 150 ° C. for 5 hours under stirring (first step).

  When a part of the obtained titanium oxide slurry was sampled and examined by X-ray diffraction, it was anatase crystalline titanium oxide. Moreover, when measured with the electron microscope, the average particle diameter of the obtained titanium oxide was 0.02 micrometer.

Under a nitrogen atmosphere, 265.8 g of strontium hydroxide octahydrate (Sr (OH) ₂ .8H ₂ O) was added to the obtained titanium oxide slurry, and the mixture was hydrated to give a slurry concentration of 1.0 mol / L (SrTiO ₃ Adjusted). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be strontium titanate having a cubic perovskite structure as shown in FIG. As a result of observation with an electron microscope, the average particle diameter was 0.05 μm, and the ratio of particles having nanometer-sized pores was 5 out of 100 particles. As a result of analysis by fluorescent X-ray, the Sr / Ti ratio was 1.00. The BET specific surface area was 22 m ² / g.

Example 9
In the same manner as in Example 1, a titanium tetrachloride aqueous solution was prepared, and 197 mL of ion-exchanged water was added to the titanium tetrachloride aqueous solution, and then 30 wt% urea kept at 80 ° C. in the titanium tetrachloride aqueous solution. 283 g of aqueous solution was added over 100 minutes. Next, the temperature is raised, boiled and refluxed for 10 hours, and then an aqueous ammonia solution having a concentration of 5% by weight is added to adjust the pH to 10, followed by washing with water until chlorine is not detected to obtain a titanium hydroxide slurry. It was. Thereafter, a titanium oxide slurry was obtained from the titanium hydroxide slurry in the same manner as in Example 8 (first step). The titanium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.03 μm.

Separately, 240 g of a 30 wt% aqueous urea solution maintained at 80 ° C. was added to 1104 g of a 30 wt% lead nitrate (Pb (NO ₃ ) ₂ ) aqueous solution (0.5 mol as lead) over 200 minutes. Next, the temperature is raised, boiled and refluxed for 10 hours, and then an aqueous ammonia solution having a concentration of 5% by weight is added to adjust the pH to 10, followed by washing with water until chlorine and nitrate ions are no longer detected. A slurry was obtained.

This lead hydroxide slurry was added to the above titanium oxide slurry, 50 g of a 20% strength by weight sodium hydroxide aqueous solution was further added, and the slurry was hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of PbTiO ₃ ). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be lead titanate having a perovskite structure. Further, as a result of observation by an electron microscope, the ratio of particles having an average particle diameter of 0.05 μm and having nanometer-sized pores was 9 out of 100 particles. As a result of analysis by fluorescent X-ray, the Pb / Ti ratio was 1.00. The BET specific surface area was 17 m ² / g.

Example 10
In a nitrogen atmosphere, 163.78 g of zirconium isopropoxide (0.5 mol as zirconium) was dissolved in 300 mL of isopropyl alcohol, and 70 mL of ion-exchanged water was added to the resulting solution over 60 minutes with stirring. A slurry was obtained. The obtained zirconium hydroxide was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.5 mol / L, and the whole amount was put into a polytetrafluoroethylene beaker, and this was charged into a 1 L capacity autoclave. The mixture was hydrothermally treated at 150 ° C. for 5 hours with stirring (first step). The zirconium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.04 μm.

To the obtained zirconium oxide slurry, 315.4 g of barium hydroxide octahydrate was added in a nitrogen atmosphere and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaZrO ₃ ). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium zirconate having a cubic perovskite structure as shown in FIG. Further, as a result of observation with an electron microscope, the ratio of particles having spherical particles having an average particle diameter of 0.08 μm and having nanometer-sized pores was 6 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / Zr ratio was 1.00. The BET specific surface area was 15 m ² / g.

Example 11
In the same manner as in Example 1, a titanium hydroxide slurry was obtained, and the resulting titanium hydroxide was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.5 mol / L. This was placed in an ethylene beaker, charged into a 1 L autoclave, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours with stirring (first step). The titanium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.02 μm.

Under a nitrogen atmosphere, 56.1 g of calcium oxide (CaO) was added to the obtained titanium oxide slurry and hydrated to adjust the slurry concentration to 1.0 mol / L (CaTiO ₃ equivalent). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be calcium titanate having an orthorhombic perovskite structure as shown in FIG. As a result of observation by an electron microscope, the average particle diameter was 0.06 μm, and the ratio of particles having nanometer-sized vacancies was 8 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ca / Ti ratio was 1.00. The BET specific surface area was 21 m ² / g.

Example 12
In the same manner as in Example 10, a zirconium oxide slurry was obtained from zirconium isopropoxide (first step). To the obtained zirconium oxide slurry, 265.8 g of strontium hydroxide octahydrate (Sr (OH) ₂ .8H ₂ O) was added under a nitrogen atmosphere and hydrated, so that the slurry concentration was 1.0 mol / L (SrZrO ₃ Adjusted). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be strontium zirconate having a perovskite structure. Further, as a result of observation with an electron microscope, the ratio of particles having spherical particles having an average particle diameter of 0.07 μm and having nanometer-sized pores was 8 out of 100 particles. As a result of analysis by fluorescent X-ray, the Sr / Zr ratio was 1.00. The BET specific surface area was 16 m ² / g.

Example 13
While maintaining 55.9 g of titanium tetrachloride (0.4 mol as titanium) at 50 ° C., this was added to 1300 mL of ion-exchanged water with stirring, and further 100 mL of zirconium oxychloride aqueous solution having a concentration of 178 g / L (0.003 as zirconium). 1 mol) was mixed to prepare a titanium tetrachloride-zirconium oxychloride mixed aqueous solution. To this titanium tetrachloride-zirconium oxychloride mixed aqueous solution, 10.0 g of a sodium hydroxide aqueous solution having a concentration of 10.0% by weight was added over 30 minutes to obtain a titanium zirconium zirconium coprecipitate slurry.

  The titanium-zirconium hydroxide coprecipitate was washed with water, filtered, and hydrated to prepare a 1.5 mol / L slurry, and the whole amount was put into a polytetrafluoroethylene beaker, which was then added to a 1 L autoclave. And a hydrothermal reaction was carried out at 150 ° C. for 5 hours with stirring (first step). The titanium zirconium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.03 μm.

To the obtained titanium-zirconium slurry, 315.4 g of barium hydroxide octahydrate was added in a nitrogen atmosphere and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTi _0.8 Zr _0.2 O ₃ ). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium zirconate titanate having a cubic perovskite structure as shown in FIG. As a result of observation by an electron microscope, the ratio of particles having an average particle diameter of 0.06 μm and having nanometer-sized pores was 3 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / (Ti + Zr) ratio was 1.00. The BET specific surface area was 18 m ² / g.

Example 14
200 mL of ion-exchanged water was added to 94.5 g of titanium tetrachloride (0.5 mol as titanium) to prepare an aqueous titanium tetrachloride solution. The titanium tetrachloride aqueous solution was added to 283 g of a 30 wt% aqueous urea solution maintained at 80 ° C. over 1 hour. Next, the temperature was raised, the mixture was boiled and refluxed for 10 hours, and then a 5 wt% aqueous ammonia solution was added to adjust the pH to 10 to obtain a titanium hydroxide slurry. The titanium hydroxide was washed with water, filtered, added with water, adjusted to a 2.0 mol / L slurry, and then heated at 80 ° C. with stirring for 10 hours (first step). The titanium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.02 μm.

The total amount of the titanium oxide slurry thus obtained was collected by filtration and placed in a polytetrafluoroethylene beaker. Under a nitrogen atmosphere, 126.2 g of barium hydroxide octahydrate and 26.6 g of strontium hydroxide octahydrate were added. And added to adjust the slurry concentration to 1.0 mol / L (Ba _0.8 Sr _0.2 TiO ₃ equivalent). Hereinafter, in the same manner as in Example 1, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium strontium titanate having a cubic perovskite structure. Further, as a result of observation by an electron microscope, the ratio of particles having an average particle diameter of 0.04 μm and having nanometer-sized pores was 4 out of 100 particles. As a result of analysis by fluorescent X-ray, the (Ba + Sr) / Ti ratio was 1.00. The BET specific surface area was 22 m ² / g.

Example 15
While maintaining 55.4 g of titanium tetrachloride (0.45 mol as titanium) at 50 ° C., this was added to 1300 mL of ion-exchanged water with stirring, and further 40 wt% aqueous tin tetrachloride (SnCl ₄ ) solution. Was added to prepare a titanium tetrachloride-tin tetrachloride mixed aqueous solution. To this titanium tetrachloride-tin tetrachloride mixed aqueous solution was added 800 g of 10.0 wt% sodium hydroxide aqueous solution over 30 minutes to obtain a titanium hydroxide tin coprecipitate slurry.

  This titanium tin hydroxide coprecipitate was washed with water, filtered, and hydrated to prepare a 1.5 mol / L slurry, and the whole amount was put into a polytetrafluoroethylene beaker, and this was put into a 1 L capacity autoclave. Then, hydrothermal reaction was performed at 150 ° C. for 5 hours under stirring (first step). The titanium tin oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.04 μm.

To the obtained titanium tin oxide slurry, 315.4 g of barium hydroxide octahydrate was added in a nitrogen atmosphere and hydrated to adjust the slurry concentration to 1.0 mol / L (in terms of BaTi _0.9 Sn _0.1 O ₃ ). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure. Further, as a result of observation with an electron microscope, the ratio of particles having spherical particles having an average particle diameter of 0.06 μm and having nanometer-size pores was 7 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / (Ti + Sn) ratio was 1.00. The BET specific surface area was 17 m ² / g.

Example 16
In the same manner as in Example 14, a titanium oxide slurry was obtained from titanium tetrachloride (first step). The total amount of the resulting titanium oxide slurry was collected by filtration and placed in a polytetrafluoroethylene beaker. Further, under a nitrogen atmosphere, 149.8 g of barium hydroxide octahydrate and magnesium hydroxide (Mg (OH) ₂ ) 5 g was added, and water was added to adjust the slurry concentration to 1.0 mol / L (in terms of Ba _0.95 Mg _0.05 TiO ₃ ). Thereafter, the second step was performed in the same manner as in Example 1.

The composition obtained in the second step is heat-treated at 800 ° C. in an electric furnace, and then wet pulverized in a nylon pot mill using zirconia balls to be referred to as a composition containing an ABO ₃ compound (hereinafter referred to as a composition). )

As a result of X-ray diffraction, this composition was confirmed to be barium magnesium titanate having a perovskite structure. As a result of observation with an electron microscope, the average particle diameter was 0.1 μm, and the ratio of particles having nanometer-sized vacancies was 8 out of 100 particles. As a result of analysis by fluorescent X-ray, the (Ba + Mg) / Ti ratio was 1.00. The BET specific surface area was 14 m ² / g.

Example 17
In a nitrogen atmosphere, 127.98 g of titanium isopropoxide (0.45 mol as titanium) and 20.74 g of hafnium isopropoxide (0.05 mol as hafnium) were dissolved in 500 mL of isopropyl alcohol and heated to reflux for 2 hours. To the resulting solution, 70 mL of ion exchanged water was added over 60 minutes with stirring to obtain a titanium hydroxide hafnium coprecipitate slurry. The obtained titanium hydroxide hafnium coprecipitate was washed with water, filtered, and hydrated to prepare a slurry having a concentration of 1.5 mol / L, and the entire amount was put into a polytetrafluoroethylene beaker, Were hydrothermally treated at 200 ° C. for 5 hours with stirring (first step). The titanium hafnium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.03 μm.

To the titanium oxide hafnium slurry thus obtained, 315.4 g of barium hydroxide octahydrate was added in a nitrogen atmosphere and hydrated to a slurry concentration of 1.0 mol / L (BaTi _0.9 Hf _0,1 O ₃ Adjusted). Hereinafter, in the same manner as in Example 2, a composition containing an ABO ₃ compound (hereinafter referred to as a composition) was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a perovskite structure. Further, as a result of observation by an electron microscope, the ratio of the particles having a spherical particle having an average particle diameter of 0.05 μm and having nanometer-size pores was 4 out of 100 particles. As a result of analysis by fluorescent X-ray, the Ba / (Ti + Hf) ratio was 1.00. The BET specific surface area was 19 m ² / g.

Example 18
While maintaining 75.9 g of titanium tetrachloride (0.4 mol as titanium) at 50 ° C., this was added to 1300 mL of ion-exchanged water with stirring, and 100 mL of 178 g / L zirconium oxychloride aqueous solution was further added. A titanium chloride-zirconium oxychloride mixed aqueous solution was prepared. To this titanium tetrachloride-zirconium oxychloride mixed aqueous solution, 10.0 g of a sodium hydroxide aqueous solution having a concentration of 10.0% by weight was added over 30 minutes to obtain a titanium zirconium zirconium coprecipitate slurry.

  The titanium-zirconium hydroxide coprecipitate was washed with water, filtered, and hydrated to prepare a 1.5 mol / L slurry, and the whole amount was put into a polytetrafluoroethylene beaker, which was then added to a 1 L autoclave. And a hydrothermal reaction was carried out at 150 ° C. for 5 hours with stirring (first step). The titanium zirconium oxide thus obtained was measured with an electron microscope and found to have an average particle size of 0.03 μm.

Under a nitrogen atmosphere, 149.8 g of barium hydroxide octahydrate and 1.9 g of calcium hydroxide (Ca (OH) ₂ ) were added to the obtained titanium zirconium oxide slurry, and the mixture was hydrated to adjust the slurry concentration to 1.0 mol / L (Ba _0.95 Ca _0.05 Ti _0.8 Zr _0.2 O ₃ equivalent) was adjusted. Thereafter, the second step was performed in the same manner as in Example 1.

The composition obtained in the second step was heat-treated at 900 ° C. in an electric furnace, and then wet pulverized in a nylon pot mill using zirconia balls, and a composition containing an ABO ₃ compound (hereinafter referred to as composition) It was called a thing.)

As a result of X-ray diffraction, this composition was confirmed to be barium calcium zirconate titanate having a cubic perovskite structure as shown in FIG. Further, as a result of observation by an electron microscope, the ratio of particles having an average particle diameter of 0.2 μm and having nanometer-sized pores was 7 out of 100 particles. As a result of analysis by fluorescent X-ray, the (Ba + Ca) / (Ti + Zr) ratio was 1.00. The BET specific surface area was 7 m ² / g.

Comparative Example 1
High purity barium carbonate and high purity titanium oxide were mixed at an equimolar ratio, sufficiently dried, and then calcined at 1200 ° C. for 2 hours. The obtained calcined product was wet pulverized in a polyethylene pot mill using zirconia balls to obtain a composition containing an ABO ₃ compound (hereinafter referred to as a composition).

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a tetragonal perovskite structure. The crystallite value calculated by applying the half-value width of the (111) plane of X-ray diffraction to the Scherrer equation was 1200 Å. As a result of observation with an electron microscope, the barium titanate particles were irregular crushed materials having an average particle diameter of 1.6 μm. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 1.2 m ² / g.

Comparative Example 2
While maintaining 94.9 g of titanium tetrachloride (0.5 mol as titanium) at 50 ° C., this was added to 1300 mL of ion-exchanged water with stirring to prepare an aqueous solution of titanium tetrachloride. To this titanium tetrachloride aqueous solution, 800 g of a 10.0 wt% sodium hydroxide aqueous solution was added over 30 minutes to obtain a titanium hydroxide slurry.

The titanium hydroxide was washed with water and collected by filtration. This was heated without heat treatment (ie, without the first step) and adjusted to a 2.0 mol / L slurry, and then the whole amount was put into a polytetrafluoroethylene beaker. Was added with 157.7 g of barium hydroxide octahydrate, and the slurry was adjusted to 1.0 mol / L (in terms of BaTiO ₃ ).

This was charged into an autoclave having a capacity of 1 L, heated to 150 ° C. in 90 minutes while stirring at 550 to 600 rpm, and subjected to a hydrothermal reaction at 150 ° C. for 5 hours. After this hydrothermal reaction, carbon dioxide gas was blown into the resulting slurry until the pH became 6.5, then water was washed until chlorine was no longer detected, filtered, dried at 110 ° C., and ABO ₃ compound. The composition (henceforth a composition) containing this was obtained.

As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a cubic perovskite structure. As a result of analysis by fluorescent X-ray, the Ba / Ti ratio was 1.00. The BET specific surface area was 13 m ² / g. However, as a result of observation with an electron microscope, the obtained composition was spherical particles having an average particle diameter of 0.1 μm, but the proportion of particles having nanometer-sized pores was 32 out of 100 particles. there were.

Comparative Example 3
The composition obtained in Comparative Example 2 was calcined in the same manner as in Example 7, and then wet pulverized to obtain a composition containing an ABO ₃ compound (hereinafter referred to as a composition). As a result of X-ray diffraction, this composition was confirmed to be barium titanate having a tetragonal perovskite structure. As a result of observation with an electron microscope, the average particle diameter of the barium titanate particles was 0.2 μm. The ratio of particles having nanometer-sized vacancies was 37 out of 100 particles.

In Example 3, it is an X-ray-diffraction figure of the titanium oxide obtained at the 1st process. In Example 3, it is a transmission electron micrograph of the titanium oxide obtained at the 1st process. In Example 3, it is an X-ray-diffraction figure of the composition obtained at the 2nd process. In Example 7, it is an X-ray-diffraction figure of the composition obtained at the 3rd process. In Example 8, it is an X-ray-diffraction figure of the composition obtained at the 2nd process. In Example 10, it is an X-ray-diffraction figure of the composition obtained at the 2nd process. In Example 11, it is an X-ray-diffraction figure of the composition obtained at the 2nd process. In Example 13, it is an X-ray-diffraction figure of the composition obtained at the 2nd process. In Example 18, it is an X-ray diffraction pattern of the composition obtained at the 2nd process.

Claims (7)

A first step of dehydrating the hydrated oxide by heating a hydrated oxide of at least one group B element selected from Ti, Zr, Hf and Sn in the presence of an aqueous medium at a temperature in the range of 80 to 300 ° C. When,
The reaction product obtained in the first step and a hydroxide of at least one group A element selected from Ba, Sr, Ca, Mg, and Pb in the presence of an aqueous medium, a temperature in the range of 100 to 300 ° C. And a second step of heating with a method for producing a composition containing a perovskite type compound.   The method according to claim 1, further comprising a third step of heat-treating the composition obtained in the second step at 100 to 1200 ° C.   The method according to claim 1, wherein, in the first step, the hydrous oxide of the group B element is heated in the presence of an inorganic acid.   The method according to claim 3, wherein the inorganic acid is nitric acid or hydrochloric acid.   In the first step, the hydrous oxide of the group B element is heated in the presence of an organic polyvalent carboxylic acid, an organic oxypolyvalent carboxylic acid, an alkali metal salt or an alkaline earth metal salt thereof. The method according to 1.   The method according to claim 1, wherein in the first step, the hydrous oxide of the group B element is heated in the presence of a base. The process according to claim 6, wherein the base is an alkali metal hydroxide or an amine.