JPH04114919A - Production of multiple perovskite-type dielectric porcelain powder and porcelain capacitor using same - Google Patents

Abstract

PURPOSE:To obtain the title powder of fine, homogeneous composition by bringing the powder of a Zr compound, one of starting materials to a specified particle size to complete the solid phase reaction at lower temperatures in a short time. CONSTITUTION:A mixture of (A) powder of a compound of an element selected from Ba, Ca, Sr and Pb, (B) Zr compound powder and (C) powder of a compound of an element selected from Ti, Hf and Th with a mean particle size of the powder B of <=0.2mum is calcined into the objective powder of the generic formula ABO3 (A is an element selected from Ba, Ca, Sr and Pb; B is an element selected from Zr, Ti, Hf and Th). The present powder is capable of forming a dielectric porcelain layer of high dielectric constant with a dielectric porcelain layer as the basic component and plural electrodes holding said component, thus obtaining the other objective small-sized, large-capacity porcelain capacitor.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing a composite perovskite dielectric ceramic powder using a solid phase reaction, and a ceramic capacitor using the powder as a basic component of a dielectric ceramic layer. It is related to.

[Prior Art] A method for producing composite perovskite dielectric ceramic powder using a solid-phase reaction involves starting with powders of various compounds such as Ba, Zr, and Ti, weighing them in predetermined amounts, and uniformly distributing them. The mixture obtained by this mixing is
A known method is to cause a solid phase reaction between compound powders by calcining at a temperature of about 0±100° C., thereby producing a composite perovskite dielectric ceramic powder.

[Problem to be solved by the invention] By the way, the composite perovskite dielectric ceramic powder has l
When manufacturing A-type capacitors, it is desirable to have fine particles from the viewpoint of lowering the sintering temperature, and from the viewpoint of improving the electrical properties such as dielectric constant and withstand voltage of ceramic capacitors, it is desirable that the composition be fine. It is desirable that it be homogeneous.

However, with the above conventional methods, it is difficult to obtain a composite perovskite dielectric ceramic powder that satisfies both fineness and homogeneity of composition at the same time.

This is because if the calcination temperature is increased in an attempt to make the composition of composite perovskite dielectric ceramic powder homogeneous, the particle size of the resulting powder becomes coarse. This is because if the firing temperature is lowered, the solid phase reaction will not proceed smoothly and the composition will become inhomogeneous.

This tendency is particularly noticeable when producing composite perovskite dielectric ceramic powder containing zirconate.

Furthermore, in recent years, as electronic devices have become smaller and more highly integrated, there has been a demand for smaller and larger capacity multilayer ceramic capacitors.

Recently, as a method for downsizing and increasing the capacity of multilayer ceramic capacitors, a method of increasing the number of dielectric layers by thinning dielectric green sheets has been attracting attention.

However, in order to make the dielectric green sheet thinner and increase the number of laminated dielectric layers, it is necessary to make the composite perovskite dielectric porcelain powder finer, and to make the composition of the composite perovskite dielectric porcelain powder homogeneous. Therefore, it is necessary to increase the insulation resistance of the dielectric layer.

However, as mentioned above, it is difficult to obtain fine composite perovskite dielectric ceramic powder with a homogeneous composition using the above conventional method. It has been difficult to miniaturize and increase the capacity of multilayer ceramic capacitors by increasing the number of capacitors.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a composite perovskite dielectric 6ri and a composite perovskite dielectric UR powder having a fine and homogeneous composition, and also to provide a method for manufacturing a composite perovskite dielectric 6ri and a ceramic powder having a small size and a large capacity. and high withstand voltage 6
The purpose of the present invention is to provide an R-type capacitor.

Means for Solving Problem U] The method for producing a composite perovskite dielectric ceramic powder according to the present invention includes a compound powder of one or more elements selected from Ba, Ca, Sr-, and Pb; -R
Formula 9 ABO3 (where A is Ba, Ca, Sr and Pb
(B is one or more elements selected from Zr and one or more elements selected from Ti, Hf, and Th)
The method for producing a pottery powder is characterized in that the average particle size of the Zr compound powder is 0.2 μm or less.

Here, as each compound of the starting material, an oxide, hydroxide, carbonate or other compound can be used.

Further, as the Zr compound, for example, Z r O2, Z r (OH) <, etc. can be used.

These compounds are mixed in a ball mill or the like to form a mixture, and this mixing may be carried out in a dry or concentrated manner.

Moreover, the calcination temperature of the mixture is preferably in the range of 900 to 1100'C. This is because, if calcined within this range, the obtained composite perovskite dielectric ceramic powder will be fine and homogeneous, but below 900'C, the in-phase reaction will not proceed sufficiently, resulting in insufficient synthesis. This is because a dense sintered body cannot be obtained, and if the temperature exceeds 1000°C, the particles become coarse and a dense sintered body cannot be obtained.

There is no need to limit the range of the calcination time (,1
~2 hours is sufficient.

In addition, the average particle size of the Zr compound powder is set to 0.2 LLm or less;
If the diameter is 2 μm or less, the solid phase reaction will proceed smoothly and the composition of the obtained composite perovskite dielectric ceramic powder will be homogeneous, but if it is larger than 0.2 μm, the in-phase reaction will not proceed sufficiently and the resulting composite This is because the composition of the perovskite dielectric ceramic powder becomes non-uniform.

In addition, the particle size of element A and element B other than Zr is 1.0L.
Lm or less is preferable. If the particle size of element A and element B other than Zr is 1.0 μm or less, the in-phase reaction will proceed sufficiently and the composition of the resulting composite perovskite dielectric ceramic powder will be homogeneous, but if the particle size is 1.0 μm. If it is larger, the solid phase reaction will not proceed sufficiently and the composition of the obtained composite perovskite dielectric ceramic powder will become non-uniform.

Furthermore, the ceramic capacitor according to the present invention includes one or more dielectric ceramic layers having the composite perovskite dielectric ceramic powder as a basic component, and one or more dielectric ceramic layers sandwiching the dielectric ceramic layer. The device is characterized by comprising an electrode.

Here, the dielectric ceramic layer contains 10 wt% of the basic component.
It can be formed by adding less than one additional component.

Examples of this additional component include Nb and Si.

Oxides, hydroxides, carbonates or other compounds such as Mn, Al, Li, Ca or Bi can be used.

In addition, a trace amount of mineralizer may be added to these additive components to improve the sinterability within a range that does not impede the purpose of the present invention, and other substances may be added as necessary. You may.

Note that the present invention is of course applicable to other single-layer ceramic capacitors other than multilayer ceramic capacitors.

[Example 1] First, the composite perovskite dielectric ceramic powder was made of barium zirconate titanate B a (T i, o, esZ ro, +5) 03
An example of the case will be described using Example 1 and Comparative Example 1.

Example 1 First, the case of sample number 1 in Table 1 will be explained.

The compounds shown in Formulation 1 were each weighed out, and these compounds were placed in a ball mill with about 2.5 g of water and stirred for about 20 hours to obtain a mixture of these compounds.

Here, each compound in Formulation 1 had a purity of 99.0% or more. In addition, the weight of each compound in Formulation 1 (
g) The general formula ABO3 of the above-mentioned composite perovskite dielectric ceramic powder is Ba (T i-a, geZro, +
s) o3 ・ill.

Next, the mixture was placed in a stainless steel pot and dried at 150° C. for 4 hours using a hot air dryer to obtain a dry mixture.

Next, this dry mixture was pulverized and calcined in the atmosphere at about 1100°C for 2 hours using a tunnel furnace.
A powder of barium zirconate titanate represented by the above compositional formula Fl) was obtained.

Next, the particle size of this barium zirconate titanate powder was measured by an air permeation method and was found to be 1.2 μm.

In addition, when the powder of barium zirconate titanate was subjected to an X-ray diffraction device, its X-ray diffraction pattern was determined.
As shown in FIG. 1, the composition was homogeneous with no variation observed.

Next, add 2 to this barium zirconate titanate powder.
After adding the compound and uniformly dispersing it by wet mixing,
It was dried to obtain a mixed powder.

Next, a binder is added to this mixed powder, granulated, and molded at a pressure of 1000 kg/cm2 to give a diameter of 10 mm.
A disk with a thickness of 1 mm was prepared and fired at 1150''C for 2 hours to obtain a disk-shaped dielectric porcelain.

Next, silver paste was applied to both sides of the fired disc-shaped dielectric ceramic and fired at 800'C for 30 minutes to convert the silver paste into electrodes, thereby obtaining a ceramic capacitor.

Next, the electrical characteristics of this ceramic capacitor were measured.

As shown in Table 1, the electrical characteristics of this ceramic capacitor include a dielectric constant (ε) of 16280 and a dielectric loss (tan δ).
is 1.9%, and the capacitance change rate (Tc) is -78 to -56.
%, and the insulation resistance was 1', 5XIO5MΩ.

The electrical characteristics of this ceramic capacitor were measured in the following manner.

(A + dielectric constant (ε) is temperature 20 'C1 frequency 1 k
The capacitance of this ceramic capacitor was measured under the conditions of Hz, voltage 1, and OVr-ms, and calculated from this capacitance, the opposing area of the electrodes, and the thickness of the dielectric ceramic.

(B) Dielectric loss (tan δ) was determined under the same conditions as for dielectric constant (ε).

(C) Capacitance change rate (Tc) was determined by measuring in a temperature range of -25°C to +85°C with +20°C as a reference.

fD) Insulation resistance was measured after applying DClooV to this ceramic capacitor for 20 seconds at a temperature of 20'C.

The case of sample number 1 has been explained above, but also for sample numbers 2 and 3, except that the particle size of the starting material zirconium oxide was 0.20 LLm in sample number 2 and 0.05 LLm in sample number 3. Powder of barium zirconate titanate was obtained in the same manner as in the case of sample number 1.

Then, using this barium zirconate titanate powder, a ceramic capacitor was prepared in the same manner as in the case of sample number 1, and its electrical characteristics were determined as shown in Table 1.

Comparative Example 1 Next, samples numbers 4 to 6 will be described as comparative examples.

In the case of sample number 4, barium zirconate titanate powder was obtained in the same manner as sample number 1, except that zirconium oxide having a particle size of 0.5 μm was used as the starting material.

The particle size of this barium zirconate titanate powder was measured by an air permeation method and was found to be 1.4 μm.

In addition, this barium zirconate titanate powder was
When the X-ray diffraction pattern was obtained using a 3-diffractometer,
As shown in Figure 2, it was heterogeneous with variations in composition.

Next, using this barium zirconate titanate powder,
A ceramic capacitor was made in the same manner as in the case of sample number 1, and the electrical characteristics of this ceramic capacitor were measured.
The results are as shown in Table 1.

In addition, in the case of sample number 5.6, as the starting material zirconium oxide, sample number 5 used a particle size of 0.3LLm, and sample number 6 used a particle size of 1, OLLm. Powder of barium zirconate titanate was obtained in the same manner as in the above case.

Using this barium zirconate titanate powder, a ceramic capacitor was prepared in the same manner as in Sample No. 1, and the electrical characteristics of this ceramic capacitor were measured, and the results were as shown in Table 1.

Next, composite perovskite dielectric ceramic powder (B a
o, soCa o, +oS r o, to) =
(T io, s5Z r O, +6) The case of 03 will be explained using Example 2 and Comparative Example 2.

Example 2 First, the case of sample number 7 in Table 1 will be explained.

The compounds shown in Formulation 3 were each weighed, placed in a ball mill together with about 2.5 f2 of water, and stirred and mixed for about 20 hours to obtain a mixture.

Each compound of Formulation 1 used here has a purity of 99.0% or more. In addition, the weight i (g) of each compound in Formulation 1 is determined by the general formula ABO, (B a o, soc
a o, +oS r o, to) (T 1 o,
aiZ r o, +s) 03...This is a value calculated to be (2).

Next, the mixture was placed in a stainless steel pot and dried at 150° C. for 4 hours using a hot air dryer, and the dried mixture was pulverized to obtain a pulverized product.

Next, this pulverized material was calcined in the atmosphere at 950°C for 2 hours using a tunnel furnace to cause a solid phase reaction, thereby obtaining a composite perovskite dielectric ceramic powder represented by the above compositional formula (2). Ta.

Next, the particle size of this composite perovskite type dielectric ceramic powder was measured by an air permeation method and was found to be 1.1 μm.

In addition, this composite perovskite dielectric ceramic powder was
When the X-ray diffraction pattern was determined using a ray diffraction device, it was found to be homogeneous with no fluctuation in composition.

Next, the compound of formulation 4 was added to this composite perovskite type dielectric ceramic powder, wet-mixed, and then dried to obtain a mixed powder.

Next, a ceramic capacitor was prepared using the mixed powder in the same manner as in Sample No. 1, and its electrical characteristics were measured, and the results were as shown in Table 2.

The case of sample number 7 has been described above, but sample number 8
, 9, except that sample number 8 used zirconium oxide with a particle size of 0.20 μm and sample number 9 used particle size of 0.05 u, m.
Composite perovskite dielectric ceramic powder was obtained in the same manner as above.

Then, using this composite perovskite dielectric ceramic powder, a ceramic capacitor was created in the same manner as in the case of sample number 1, and the electrical characteristics of this ceramic capacitor were measured, and the results were as shown in Table 1. .

Comparative Example 2 Next, as Comparative Example 2, the cases of sample numbers 10 to 12 will be described.

In the case of sample number 10, sample number 7
Composite perovskite dielectric ceramic powder was obtained in the same manner as in the case of .

The particle size of this composite perovskite dielectric ceramic powder was measured by an air permeation method and was found to be 1.1 μm.

In addition, this composite perovskite dielectric ceramic powder was
When the X-ray diffraction pattern was obtained using a ray diffraction device,
It was heterogeneous with fluctuations in composition.

Next, a ceramic capacitor was made using this composite perovskite dielectric ceramic powder in the same manner as in the case of sample number 1, and the electrical characteristics of this ceramic capacitor were measured, as shown in Table 1. Ta.

In addition, in the case of sample number 11.12, the starting material zirconium oxide is different from the case of sample number 7, except that sample number 11 uses a particle size of 0.3 μm and sample number 12 uses a particle size of 1.0 μm. Composite perovskite dielectric ceramic powder was obtained in the same manner.

Then, using this composite perovskite dielectric ceramic powder, a ceramic capacitor was created in the same manner as in the case of sample number 1, and the electrical characteristics of this ceramic capacitor were measured, and the results were as shown in Table 1. .

As explained above, the samples marked with 2Ω in Table 1 are comparative examples, and when a particle size of 0.2 μm or less is used as the starting material zirconium oxide, the sample is a composite perovskite that is fine and homogeneous in composition. It can be seen that type dielectric porcelain powder can be obtained.

Furthermore, as shown in Table 1, it can be seen that dielectric ceramics containing this powder as a basic component have significantly improved electrical properties such as dielectric constant and insulation resistance.

On the other hand, it can be seen that when a starting material of zirconium oxide having a particle size larger than 0.2 μm is used, the composition of the obtained composite herovskite dielectric ceramic powder becomes non-uniform.

Furthermore, as shown in Table 1, it can be seen that dielectric ceramics containing this powder as a basic component have poor electrical properties such as dielectric constant and insulation resistance.

[Effects of the Invention] According to the present invention, since the average particle size of the zirconium oxide powder, which is one of the starting materials, is set to 0.2 μm or less, the in-phase reaction can be completed at a relatively low temperature and in a short time. Therefore, the particle size of the obtained powder does not become coarse, and a composite perovskite dielectric ceramic powder having a fine particle size distribution can be obtained.

According to the present invention, the solid phase reaction can be completed at a relatively low temperature and in a short time, so that a composite perovskite dielectric ceramic powder can be manufactured at low cost.

Further, according to the present invention, since the average particle size of the zirconium oxide powder, which is one of the starting materials, is 0.2 μm or less,
The in-phase reaction proceeds smoothly, and it is possible to obtain a composite perovskite dielectric ceramic powder with a homogeneous composition, that is, a composite perovskite dielectric ceramic powder with a high dielectric constant and high insulation resistance.

Furthermore, according to the present invention, it is possible to obtain a composite perovskite type dielectric ceramic powder with a high dielectric constant, so it is possible to form a dielectric ceramic layer with a high dielectric constant. can be manufactured.

Furthermore, according to the present invention, it is possible to obtain a composite perovskite dielectric ceramic powder with high insulation resistance, so it is possible to form a dielectric ceramic layer with high insulation resistance, and therefore, the lamination density of the dielectric ceramic layer is It is possible to manufacture small, large-capacity porcelain capacitors by increasing the

Furthermore, according to the present invention, it is possible to obtain a composite perovskite dielectric ceramic powder having a fine particle size distribution.
The dielectric ceramic layer can be sintered at a lower temperature than before,
Therefore, a ceramic capacitor can be manufactured at low cost.

[Brief explanation of the drawing]

Figure 1 shows the X-ray diffraction pattern of the composite perovskite dielectric porcelain powder according to sample number 1 (Example 1), and Figure 2 shows the composite perovskite dielectric porcelain powder according to sample number 4 (comparative example 1). It is a figure which shows the X-ray diffraction pattern of powder. Agent Patent Attorney Kubo 1) Akira Hou

Claims (2)

[Claims] 1. Compound powder of one or more elements selected from Ba, Ca, Sr and Pb, compound powder of Zr, and Ti
, Hf, and a compound powder of one or more elements selected from Th.
_3 (However, A is one or more elements selected from Ba, Ca, Sr and Pb, B is Zr, Ti, Hf
and Th) A method for producing a composite perovskite dielectric ceramic powder represented by A method for producing a composite perovskite dielectric ceramic powder. 2. It is characterized by comprising one or more dielectric ceramic layers whose basic component is the composite perovskite dielectric ceramic powder according to claim 1, and at least two or more electrodes sandwiching the dielectric ceramic layers. porcelain capacitor.