JPS61111957A - Composition for ceramic dielectric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic dielectric composition and a ceramic dielectric obtained by firing the same.
Contains the following particles, and is made of a cubic perovskite compound sintered body by firing at a low temperature of 1100°C or less, has virtually no piezoelectricity, and has very little temperature change in capacitance. A composition that provides a ceramic dielectric material that is small in size and has excellent electrical properties such as insulation resistance and low dielectric loss tangent, a method for manufacturing a ceramic dielectric material using this composition, and a ceramic dielectric material obtained in this way. Regarding the body.

In general, a perovskite compound is a compound that has a crystal structure similar to that of calcium titanate (KC perovskite), and by molding and sintering such a compound, a dielectric material having dielectricity, piezoelectricity, and semiconductivity can be produced. In recent years, these ceramics have been used in large quantities in electronic devices such as communication devices and computers as capacitors, radio wave filters, ignition elements, thermistors, etc.

Conventionally, perovskite compounds contain Mg%Ca.

Carbonate or oxide such as 3rSBasPb and Ti%Zr
It is manufactured by mixing s Hrs with an oxide such as Sn, calcining it at a temperature of 1000° C. or higher, wet-pulverizing it, and filtering and drying it. However, according to this method, since the perovskite compound is aggregated by calcination, it is difficult to reduce the particle size to 1 μm or less even by wet grinding, and the shape after grinding is also similar to that of crushed particles. It is. Therefore, when forming and sintering perovskite compound particles by the calcination method to make a dielectric material, not only are the sintering properties poor, but also the crystal growth of the particles to a particle size of about 5 to 10 μm occurs due to sintering. ,
It is not possible to obtain a sintered body consisting of fine particles.

In particular, a multilayer ceramic capacitor is integrally formed by alternately laminating a ceramic dielectric made of a sintered body of a perovskite compound and an electrode metal, and the ceramic dielectric is typically made of barium metatitanate (BaT).
As mentioned above, conventional perovskite compound sintered bodies have large sintered particles and are said to be optimal as dielectric materials for capacitors. There is a large gap between particle diameters of about 0.5 to 1 μm.

Furthermore, conventional perovskite compounds such as barium metatitanate as described above have large particle sizes, so in order to increase the degree of sintering and obtain a dense sintered body, for example,
In the case of the above-mentioned multilayer ceramic capacitor, it is necessary to heat it together with the seed metal to a high temperature of about 1,300 to 1,400°C. There is no choice but to use a high melting point noble metal iai type.

Therefore, in order to use a relatively low melting point and inexpensive metal material such as silver as the internal electrode of a multilayer ceramic capacitor, we mixed a low melting point glass composition powder and perovskite compound particles and compared them. Although methods of sintering at relatively low temperatures have been proposed (for example, K, R, C
howdary at al.

Ferroelectrics, 1981. Vol.
, 37. pp, 689-692゜Unexamined Japanese Patent Publication No. 54-6
6450, etc.), the particle size of the perovskite sintered body is large, so the performance of the obtained multilayer ceramic capacitor is still not satisfactory.

As a result of intensive research to solve the above-mentioned problems in the production of perovskite compounds and the production of ceramic dielectrics by sintering the same, the inventors of the present invention have found that the particle size of perovskite-type compounds, which are substantially cubic crystals, is 1 μm. The following fine particles have excellent sintering properties, and by firing them at a low temperature of 1100°C or less using a low melting point substance as a liquid phase, they are essentially made of cubic perovskite compound sintered bodies and have excellent electrical properties. (Thus, for example, it is possible to use a metal with a low melting point as an internal electrode material, thereby reducing the cost of manufacturing the electrodes of a multilayer ceramic capacitor. The present invention has been made based on the discovery that a dielectric material is substantially free from piezoelectric phenomena, has very small temperature change in capacitance, and has excellent electrical properties such as insulation resistance and dielectric loss tangent. This is what we have come to.

Therefore, an object of the present invention is to provide a composition for a ceramic dielectric material and a ceramic dielectric material obtained by firing the composition, and in particular, it is an object of the present invention to provide a composition for a ceramic dielectric material and a ceramic dielectric material obtained by firing the same. It is composed of particles and a low melting point glass substance, and by firing at a low temperature of 1100 degrees Celsius or less, it has excellent dielectric properties, in particular, very little temperature change in capacitance, and has substantially piezoelectric properties. It is an object of the present invention to provide a composition for a ceramic dielectric which provides a ceramic dielectric having a high insulation resistance and a low dielectric loss tangent, a ceramic dielectric obtained from such a composition, and a method for manufacturing the same.

The ceramic dielectric composition according to the present invention is composed of ('')Mg
s At least one element selected from Group A consisting of Ca, Sr, Ba and Pb, and Ti, Z r s H
and (b) particles having a particle size of 1 μm or less and consisting of a substantially cubic perovskite compound containing at least one element selected from Group B consisting of It is characterized by consisting of a certain low melting point substance powder.

Further, the method for manufacturing a ceramic dielectric according to the present invention includes: (a) at least one element selected from Group A consisting of Mgs Ca%Sr, Ba, and Pb;
, Hf and Sn.
and (b) a compound of at least one element selected from the group consisting of Bi, B5Pb, and W. It is characterized in that it is mixed with a powder of a low melting point substance containing powder and fired at a temperature of 1100°C or less.

The perovskite compound particles used in the ceramic dielectric composition of the present invention contain at least one element selected from the above group A and at least one element selected from the above group B.
These are fine particles having a particle size of 1 μm or less, which are made of a perovskite compound having a substantially cubic crystal structure and containing seed elements.

As is already known, particles of a fine perovskite compound having a substantially cubic crystal structure are hydroxides of at least one element selected from Group A (hereinafter referred to as A hydroxide). , ) and a hydroxide of at least one element selected from Group B (hereinafter referred to as B hydroxide), and then hydrothermally treated. It is known that by mixing hydroxide A and hydroxide B, a part of a perovskite compound is formed. Alternatively, the mixture may be a mixture of perovskite compounds having a low degree of crystallinity as a whole.

The above-mentioned hydroxide mixture can be prepared, for example, by using A as a simple method.
It can be prepared by mixing hydroxide and B hydroxide. As another method, for example, a mixture of a salt of a group A element and a salt of a group B element may be reacted with an alkali (or a hydroxide (or salt) of a group A element and a salt of a group B element). (or hydroxide) may be reacted with an alkali.

Furthermore, as another method, a hydroxide (or alkoxide) of a group A element and an alkoxide (or hydroxide) of a group B element
(Alternatively, a mixture of an alkoxide of a group A element and an alkoxide of a group B element may be hydrolyzed.

Next, by hydrothermally treating the hydroxide mixture as described above, particles of a substantially cubic perovskite compound that can be suitably used in the present invention with a diameter of 1 μm are obtained.
It is possible to obtain fine particles with a force C of less than m. As is already known, hydrothermal treatment refers to heat treatment in an alkaline aqueous medium, and in the present invention, hydrothermal treatment is performed at a reaction temperature of 100°C to the critical temperature of the aqueous medium as necessary. Accordingly, after adding an alkali, the hydroxide mixture, which is alkaline in nature, may be heated.

When the hydrothermal treatment temperature is lower than 100°C, the reaction between hydroxide A and hydroxide B does not proceed sufficiently, and the desired perovskite compound cannot be obtained in high yield.On the other hand, the reaction temperature The higher the value of
The temperature is preferably 120 to 300°C, usually 120 to 300°C. After this hydrothermal treatment, by filtering the slurry-like reaction mixture and drying the solid content, fine perovskite compound particles with a particle size of 1 μm or less can be obtained.

In the above hydrothermal treatment, the degree of alkalinity of the aqueous medium, that is, the excess degree and concentration of the alkali, may be adjusted as appropriate, but in general, the higher the excess degree of the alkali, the better the perovskite compound particles obtained. The particle size of the particles becomes smaller. Furthermore, the higher the concentration of A hydroxide and qB hydroxide in the aqueous medium, the smaller the particle size of the obtained perovskite compound. Therefore, the degree of excess of alkali and the concentration of each hydroxide in the hydrothermal treatment may be selected depending on the required particle size.

As described above, perovskite compound particles obtained by hydrothermal synthesis are different from perovskite compound particles obtained by conventional calcination methods, and are composed of perovskite compounds whose crystal structure is substantially cubic, and have a particle size of 1 μm. Hereinafter, since they are usually spherical fine particles in the range of 0.01 to 1 μm, they have a large surface energy and a uniform particle size distribution.

Particles of a fine perovskite compound having a substantially cubic crystal structure can be produced by, in addition to the hydrothermal synthesis described above, a metal alkoxide method, which is generally called a solution method, or a metal alkoxide method, which is generally called a solution method. It can also be obtained by coprecipitation method etc.
~8 pages).

In the metal alkoxide method, water is added to a mixture of an alkoxide of at least one element selected from Group A and an alkoxide of at least one element selected from Group B, and the alkoxide is hydrolyzed to form a perovskite compound. This is what you get. In addition, the alkoxide of a group A element may be hydrolyzed with a hydroxide of a group B element. In addition, generally known coprecipitation methods include the hydroxide coprecipitation method and the organic acid salt method. It is being In the hydroxide coprecipitation method, a mixed solution of salts of group A elements and salts or hydroxides of group B elements is reacted with an alkali to form hydroxides of group A elements and group B elements. obtain a mixture with hydroxide and, if necessary, add 50
A perovskite compound is obtained by firing at a temperature of about 0 to 900°C. For example, a cubic perovskite compound can be obtained by adding a titanium tetrachloride solution to 78 barium hydroxide solutions containing excess sodium hydroxide. Obtainable. The organic acid salt method uses salts of group A elements and B
A water-insoluble composite salt of an organic acid containing a group A element and a group B element is obtained by reacting an organic acid with a mixture of a salt of a group element, and the mixture is heated at a temperature of about 50° to 90°C. This is a method of obtaining a perovskite compound by thermal decomposition with .For example, a method using oxalic acid or citric acid as an organic acid is known.

As described above, particles with a particle size of 1 μm or less consisting of a substantially cubic perovskite compound can be obtained by any of the hydrothermal synthesis method, metal alkosite method, and coprecipitation method, and in the present invention, particles with a particle size of 1 μm or less can be obtained. All such perovskite compound particles can be used. In particular, since the particles obtained by the conventional hydrothermal synthesis method as described above are spherical, the filling property is excellent and a dense sintered body can be obtained. Furthermore, as will be described later, when making a sintered dielectric material using a low melting point substance as a matrix, the sintered particles of the perovskite compound have the advantage of being uniformly dispersed in the matrix. According to a method of hydrothermally synthesizing a mixture of titanium oxide to obtain fine and spherical cubic barium titanate (Kubo Teruichi et al., Industrial Chemistry Magazine, Vol. 71, No. 1, pp. 114-118 (196
8)), it is generally difficult to complete the reaction, and unreacted Ba salt is eluted when the reaction mixture is washed with water and filtered after the hydrothermal reaction, so the barium titanate obtained is calcined. However, it may not be easy to obtain a sintered body having the required B a /T i ratio.

On the other hand, according to the metal alkoxide method and the coprecipitation method described above, it is possible to obtain particles having a particle size of 1 μm or less and consisting of a substantially cubic perovskite compound, and
Since it is possible to obtain a perovskite compound having a predetermined ratio of group A elements to group B elements (hereinafter sometimes simply referred to as A/B ratio), An excellent ceramic dielectric material can be obtained. However, since the perovskite compound particles obtained by this method tend to aggregate, when a sintered dielectric material having a low melting point substance is used as a matrix, the perovskite compound particles may not be uniformly dispersed in the matrix.

Therefore, in the present invention, when obtaining perovskite compound particles by a hydrothermal synthesis method, an insolubilizer is added as an additive to insolubilize group A elements such as Ba after the hydrothermal treatment of the hydroxide mixture. As a result, it consists of a substantially cubic perovskite compound, and the particle size is 1.
It is preferable to use perovskite compound particles that are micrometer or smaller, fine and spherical, and have a predetermined ratio of group A elements to group B elements.

Generally, when a perovskite compound is obtained by hydrothermal synthesis, when the reaction is not completed, group B elements, such as Ti, exist as solid compounds in the aqueous medium after the reaction, and group A elements, such as Ti, are present as solid compounds in the aqueous medium after the reaction. Since Ba exists as a water-soluble compound, B is removed at the stage of filtering and washing the reaction product with water.
a compound elutes, resulting in the required B a /T
It is not possible to obtain a perovskite compound having a ratio of By immobilizing them as water-insoluble compounds, Group A elements can remain in the reaction product even when the reaction product is filtered or washed with water.Thus, by drying and calcining the reaction product, the required amount can be obtained. A perovskite compound sintered body having a high element ratio can be obtained.

As such an insolubilizing agent, it is preferable to use compounds or resins in which the insolubilized product of group A elements has low solubility in an aqueous medium, and which thermally decomposes during firing and does not remain in the sintered body. . Specifically, examples include carbon dioxide gas, carbonic acid compounds such as sodium carbonate and ammonium carbonate, alkali metal salts of fatty acids such as lauric acid, myristic acid, valmitic acid, and stearic acid, oxalic acid, malonic acid, ketomalonic acid, and stone liquor. Examples include acids, polybasic acids such as succinic acid or alkali metal salts thereof, and cation exchange resins such as Amberlite IRC-50.

Further, as the insolubilizing agent, it is also possible to use an agent that remains in the sintered body but does not have any residual influence on the properties of the sintered body. Examples of such an insolubilizer include silica such as zeolite, an aluminum-based inorganic ion exchanger, and the like.

Thus, according to the present invention, after insolubilizing the A group elements in the aqueous medium after hydrothermal treatment, the reaction product is filtered, washed with water, and dried in accordance with a conventional method to obtain the required A.
/B ratio can be obtained.

As mentioned above, the cubic perovskite compound particles obtained by insolubilizing group A elements after hydrothermal treatment have a fine spherical shape with a particle size of 1 μm or less and have a predetermined A/B ratio. It has excellent properties and dispersibility, and has high sinterability.
By sintering at low temperature.

It forms dense and strong sintered particles, and compared to conventional ceramic dielectrics, even if the film is made thinner, stable performance can be obtained.

Therefore, in the ceramic dielectric composition according to the present invention, when a perovskite compound is obtained by hydrothermal synthesis, the above-mentioned insolubilizing agent, the group A element compound insolubilized by the insolubilizing agent, and the unreacted group B element are combined. It is permissible to include small amounts of oxides, etc.

Furthermore, in -a, it is known that when sintering perovskite compound particles, the particle growth and electrical properties of the sintered body can be controlled by the action of additives. Various known additives can be used. Examples of such additives include B and Bi.
In addition, alkali metals such as L11Na% K, Y%Dy
%Ce.

Rare earth elements such as Sm, F e , M n s Co %
Examples include compounds of transition metals such as N t sNb, and further elements such as Si%AI. Such additives may be added at any stage of the preparation of the perovskite compound and its calcination, and therefore the compositions of the invention may contain such additives.

The composition for a ceramic dielectric according to the present invention consists of particles substantially consisting of a perovskite compound as described above and a powder of a low melting point substance having a melting point of 1100° C. or less. It is particularly preferred that this low melting point material has a melting point in the range 400-1000°C, and therefore typically Bt
, B SP b, and W.

The ceramic dielectric according to the present invention is produced by forming a mixture of fine particles substantially consisting of a perovskite compound and a powder of a low melting point substance as described above into, for example, granules in order to improve sinterability. By firing at a temperature of 1100° C. or lower, a dense and strong sintered body can be obtained.

Thus, in general, when a perovskite compound is sintered in the presence of a low melting point substance, the higher the ratio of the low melting point substance to the perovskite compound, the higher the degree of sintering of the sintered body, while the relative dielectric constant known to decrease.

Therefore, the proportion of the low melting point substance to the perovskite compound is appropriately selected in consideration of the degree of sintering and relative dielectric constant of the sintered particles, but usually the low melting point substance is 1 to 30% by weight based on the perovskite compound. It is recommended that 3~
The content is preferably 15% by weight.

As described above, according to the ceramic dielectric composition according to the present invention, since the perovskite compound particles are fine particles having a substantially cubic crystal grain size of 1 μm or less, a low melting point substance is used as a liquid phase. By firing at a low temperature of 1100° C. or lower, a dense and strong sintered body can be quickly obtained. Furthermore, the ceramic dielectric material thus obtained from the composition of the present invention has substantially no piezoelectricity (and , temperature change in capacitance is very small, and furthermore, it has high insulation resistance and low dielectric loss tangent.

Moreover, when obtaining this ceramic dielectric, according to the composition of the present invention, a ceramic sintered body that is dense and strong and has the above characteristics can be obtained by firing at a low temperature of 1 too°C or less. A metal material with a low melting point such as can be used as a pole inside, and
Since thermal energy can also be saved, the cost of manufacturing the electrodes of multilayer ceramic capacitors can be significantly reduced.

Furthermore, in the composition of the present invention, when a perovskite compound obtained by hydrothermal synthesis is used, the particles are spherical and have excellent dispersibility and filling properties, so that the perovskite compound particles have particularly excellent sinterability. You can get a body. On the other hand, when a perovskite compound is obtained by a metal alkoxide or a coprecipitation method, the ratio of group A elements/group B elements can be set to a predetermined ratio. You can get a body.

In particular, perovskite compound particles obtained by insolubilizing group A elements after hydrothermal treatment have the ratio of group A elements/group B elements regulated to a predetermined value, and have excellent sinterability and dielectric properties. , since the sintered particles of perovskite compound are finely and uniformly dispersed in the matrix of low melting point material,
The film can be made much thinner than conventional ceramic dielectrics, and for example, ceramic capacitors can be further downsized and stable performance can be ensured.

The present invention will be specifically explained below with reference to Examples.

Example 1 Partially hydrated titanium chloride (partially hydrated titanium tetrachloride)
TiC1g, sh (OH) t, &4, Ti16
．． 5 and 28.8% by weight of chlorine) aqueous solution (manufactured by Osaka Titanium ■, hereinafter referred to as titanium chloride aqueous solution) 13
Add 1250 ml of water to 9 g (0.48 mol as Ti), and add 483 s+ of 5.0 wt% ammonia water to this aqueous solution.
1 was added over a period of 30 minutes to obtain titanium hydroxide. After washing this titanium hydroxide with water, it was separated by filtration, and barium hydroxide octahydrate salt (Ba (OH) z・8
HzO) 151.4 g (0.48 as Ba
mol) and added water to bring the concentration to 0 as BaTi0*.
．． A slurry adjusted to 8 mol/l was obtained.

600 ml of this slurry was charged into a Hastelloy CAIZ capacity autoclave, heated to 200° C. after 90 minutes while stirring at 700 to 900 rpm, and heated at 200° C. for 5 hours for hydrothermal treatment. After this, the slurry was washed with water and filtered to obtain BaTiO3.

As a result of observation with an electron microscope, this BaTiOs was found to be spherical with an average particle size of 0.1 μm, and X-ray diffraction showed a peak unique to cubic BaTiOs. Figure 1 shows an electron micrograph of BaTioz particles obtained in this example (2000
0 times).

Separately, 3.95 g of boron oxide (Btus) and 94.20 g of bismuth oxide (Bi*Os) were thoroughly mixed in a mortar, and then heated to a temperature of 700° C. in a platinum crucible to melt them. This melt was poured into water, rapidly solidified, and then ground in a mortar and ball mill to obtain BzOz
- A powder of Biz02 low melting point substance was obtained.

Next, based on the previously obtained BaTiOi, the above-mentioned low melting point substances were added in proportions of 5% by weight, 10% by weight and 15% by weight, respectively, and after thorough mixing in a mortar, 8% by weight of polyvinyl An aqueous alcohol solution was added to the mixture to form granules, which were then pressure-molded at a pressure of 1000 kg/lj to obtain green pellets with a diameter of 20 tablets.

The green pellets were heated at a temperature of 400° C. for 3 hours to thermally decompose and volatilize the polyvinyl alcohol, and then fired at a predetermined temperature for 1 hour to obtain a sintered ceramic body, and the sintered density was measured.

Next, both sides of this sintered ceramic body were polished to a thickness of about 1 mm, both sides were coated with silver using an ion coater, and the electrical properties were measured. The relative dielectric constant and dielectric loss were measured using an LF impedance analyzer manufactured by Yokogawa Hewlett-Packard, and the insulation resistance was measured using a PA meter manufactured by Yokogawa Hewlett-Packard.

The table shows the sintered density, dielectric constant, dielectric loss tangent, and resistivity of the sintered body obtained above. From these results, it is clear that the dielectric ceramic composition according to the present invention has excellent sinterability and electrical properties. It is clear that this provides an excellent ceramic dielectric. Further, the X-ray diffraction diagram of the sintered ceramic body of Experiment No. 4 in the table thus obtained is shown in FIG.

In addition, the temperature changes in relative permittivity of typical ceramic dielectrics according to the present invention in experiment numbers 1.4 and 7 in the table are shown in Figure 3, respectively. was applied for 30 minutes to cause polarization, and the electromechanical coupling coefficient kp value was measured. Both are k
The p value was almost O, and piezoelectricity was not exhibited.

Comparative Example 1 High purity barium carbonate and titanium oxide (both Sakai Chemical Industry a)
(manufactured by L.L.) in an equimolar ratio, calcined at 1200°C for 2 hours, and then wet-pulverized in a ball mill to obtain an average particle size of 1.6 μm.
m of BaTiOs was obtained. FIG. 4 shows an electron micrograph of this perovskite compound particle.

5% by weight of the low melting point substance powder obtained in Example 1 was added to this and thoroughly mixed in a mortar. A sintered body was produced in the same manner as in Example 1, and its physical properties and electrical properties were evaluated. The results are shown in the table.

Comparative Example 2 5% by weight of the low melting point substance powder obtained in Example 1 was added to commercially available pure BaTiOs having an average particle size of 1.3 μm. After thorough mixing in a mortar, a sintered body was produced in the same manner as in Example 1, and its physical properties were measured. The results are shown in the table.

Example 2 BaTi0! obtained by hydrothermal treatment in the same manner as in Example 1!
The slurry was washed with water and filtered, and Ba in the entire filtrate was analyzed by atomic absorption spectrophotometry, and the reaction rate was 98.3%.

However, the reaction rate is [(number of moles of Ba charged - Ba in the filtrate)
It is defined as (number of moles)/number of moles of Ba charged) xloo.

After the above filtration, the solids were dispersed in the filtrate again at a temperature of 110°C, and carbon dioxide gas was blown into the solution until the pH reached 6.5, followed by washing with water, filtration, and drying until no chlorine was detected. Obtained. Analysis of the Ba/Ti ratio using fluorescent X-rays revealed that it was 1.00, and the particle size was 0.1 μm.

Add 5% of the low melting point substance powder obtained in Example 1 to this BaTiOs.
After adding % by weight and thoroughly mixing in a mortar, a sintered body was prepared in the same manner as in Example 1, and its physical properties and electrical properties were evaluated. The results are shown in the table.

Example 3 76°7 g of barium isopropoxide (
0.30 mol as Ba) and 85.3 g of titanium isopropoxide (0.30 mol as Ti) were dissolved in isopropyl alcohol 320 #11 and heated under reflux for 2 hours. To this solution, 65 ml of decarbonated ion-exchanged water was gradually added over 30 minutes to hydrolyze the alcoholade, and after cooling to room temperature, water was further added to make the slurry concentration 0.5 in terms of BaTiOs. It was adjusted to mol/e.

Thereafter, a sintered body was obtained in the same manner as in Example 1, and its sintering properties and electrical properties were evaluated. The results are shown in the table.

Example 4 30% strontium chloride (SrCh) under nitrogen atmosphere
31.7 g of aqueous solution (0.06 mol as Sr), 255.5 g of 26% by weight barium chloride pentahydrate (BaC11.2HzO) aqueous solution (0.24 mol as Ba), and 87.1 g of titanium chloride aqueous solution (as Ti). 0.30 mol) was mixed, and this mixed aqueous solution was maintained at 60°C.
It took 1 hour to add to 184 g of aqueous sodium hydroxide solution, and then water was added to adjust the slurry concentration to Baa, 1Sro,
It was adjusted to 0.5 mol/l as zTiO*.

Thereafter, a sintered body was obtained in the same manner as in Example 1, and its sintering properties and electrical properties were measured. The results are shown in the table.

Example 5 12 g of germanium oxide (GeOx) and lead oxide (
After thoroughly mixing 42.7 g of PbO) in a mortar, the mixture was heated to 800° C. using a platinum crucible to melt. This melt was poured into water, rapidly cooled and solidified, and then ground in a mortar and ball mill to obtain a Pb5Ge30++ low melting point substance.

Thereafter, 10% by weight of the low melting point substance powder obtained above was added to the BaTiOs obtained in Example 1, and after thoroughly mixing in a mortar, green pellets were obtained in the same manner as in Example 1.

The obtained green pellets were heated at 400° C. for 3 hours to decompose and volatilize the polyvinyl alcohol, and then baked at a predetermined temperature for 30 minutes. Thereafter, a sintered body was obtained in the same manner as in Example 1, and the sintering properties were measured. The results are shown in the table.

Comparative Examples 3 and 4 The Pb%Ge, O, low melting point substance powder obtained in Example 4 was mixed with BaTi0. After adding tOW amount % to each and thoroughly mixing in a mortar, green pellets were obtained in the same manner as in Example 1.

The obtained green pellets were fired in exactly the same manner as in Example 4, and then a sintered body was obtained in the same manner as in Example 1, and the sintering properties and electrical properties were measured.

The results are shown in the table.

[Brief Description of the Drawings] Figure 1 shows BaT obtained by hydrothermal treatment according to the present invention.
Electron micrograph showing iOs particle structure (20,000x magnification)
, FIG. 2 is an X-ray diffraction diagram of a sintered ceramic body according to the present invention, and FIG. 3 is a dielectric diagram of experiment numbers 1, 4, and 7, which are representative ceramic dielectric bodies obtained from a composition according to the present invention. Figure 4 is an electron micrograph (20,000x magnification) showing the BaTioz particle structure obtained by the conventional calcination method. Patent Applicant Sakai Chemical Industry Co., Ltd. Agent Patent Attorney Ittsu Makino Department Figure 3 51! Figure 4

Claims (1)

[Claims] (1) (a) At least one element selected from Group A consisting of Mg, Ca, Sr, Ba and Pb and at least one element selected from Group B consisting of Ti, Zr, Hf and Sn. and (b) a low melting point substance powder having a melting point of 1100° C. or less. thing.