JP3055344B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition having a high dielectric constant, a small temperature change, and a small dielectric loss.

[0002]

2. Description of the Related Art Hitherto, as a material for a high dielectric constant ceramic capacitor, a dielectric ceramic composition containing barium titanate as a main component has been widely used. Among them, as the material having a small change in the dielectric constant with temperature, many compositions are known, including barium titanate-bismuth system, barium titanate-niobium pentoxide-manganese dioxide system (JP-A-51-76597). Have been.

Further, in order to meet the recent demand for a multilayer ceramic capacitor having a small size and a large capacity, the dielectric constant of a dielectric material and the thickness of a dielectric layer are rapidly progressing. Therefore, with a high dielectric constant, the temperature change of the dielectric constant is small,
The demand for a dielectric material having a small dielectric loss has become extremely large.

[0004]

However, most of the above-mentioned conventional dielectric porcelain compositions use barium titanate obtained by a solid-phase reaction from barium carbonate and titanium oxide as a raw material. The dielectric constant is 3000 or less.

In general, in a ferroelectric material such as barium titanate, as the applied electric field intensity increases, the change in the dielectric constant increases and the dielectric loss also increases. Since the characteristics of the capacitor are evaluated at a signal voltage of 1 Vrms, a high signal electric field is applied as the dielectric layer becomes thinner, and the signal voltage characteristics of the conventional dielectric ceramic composition are poor. However, there has been a problem that the dielectric loss rapidly increases with an increase in the signal voltage, and the standard cannot be satisfied.

The present invention solves the above-mentioned conventional problems, and provides a dielectric ceramic composition having a high dielectric constant, a small temperature change, a small dielectric loss, and a good signal voltage characteristic. Aim.

[0007]

In order to achieve this object, a dielectric porcelain composition of the present invention is produced by a hydrothermal synthesis method,
Total I Ri specific surface area in the heat treatment on 0.8~2.4m ² / g 100 parts by weight of barium titanate adjusted to, 0.8 to 1.5 parts by weight of niobium pentoxide, the nickel oxide manganese oxide 0.1 parts by weight or more, and niobium pentoxide,
The weight ratio of nickel oxide and manganese oxide is 3 ≦ niobium pentoxide / (nickel oxide + manganese oxide) (however,
Excluding nickel oxide 0 parts by weight and manganese oxide 0 parts by weight)
Lanthanum oxide, cerium oxide
, Neodymium oxide, samarium oxide, dysprosium oxide
Of uranium, ytterbium oxide and praseosium oxide
Formed by adding 0.05 to 0.50 parts by weight of at least one kind of
It was done.

[0008]

According to the dielectric porcelain composition of the present invention, it is produced by a hydrothermal synthesis method and has a specific surface area of 0.8 to 2.
By using barium titanate of very high purity and good crystallinity adjusted to 4 m ² / g, a specific amount of niobium pentoxide, nickel oxide, and manganese oxide are added to the barium titanate. It is possible to obtain excellent characteristics with a high dielectric constant, a small temperature change in the dielectric constant, and a small dielectric loss of 2.5% or less when a signal voltage of 50 Vrms / mm is applied. Then, by adding a specific amount of lanthanum oxide, cerium oxide, neodymium oxide, samarium oxide, dysprosium oxide, ytterbium oxide or praseosium oxide to the above composition, the sinterability is improved without impairing the above-described properties. That is, the effect of being able to do so is obtained.

[0009]

(Example 1) This example corresponds to the first aspect of the present invention, and a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment. The problem has been solved by adding nickel oxide and manganese oxide and further adding lanthanum oxide .

First, a particle size of 0.1 produced by hydrothermal synthesis is used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted into Nb ₂ O ₅ , nickel oxide is converted into NiO, manganese oxide is converted into MnO ₂ , and lanthanum oxide is converted into La ₂ O _3.
In conversion, the amounts shown in the following (Table 1) were weighed.
In Table 1, niobium pentoxide, nickel oxide, manganese oxide, and lanthanum oxide are simply referred to as Nb, Ni, Mn , and L , respectively.
a .

These are placed in a polyethylene container with a diameter of 5 m.
The mixture was mixed with pure water for 20 hours by a ball mill containing zirconia balls of m. After mixing, the slurry was granulated by adding 9% by weight of a 5% PVA (polyvinyl alcohol) aqueous solution to the dried powder. Then, the granulated powder was put into a mold, and 1 to 15 mm-diameter and 0.5 mm-thick discs were formed.
It was molded at a pressure of n / cm ³ . The molded body thus obtained was fired at 1300 to 1400 ° C. for 2 hours, and silver electrodes were baked and applied to both surfaces of the fired body to obtain a sample for measurement . Then, at room temperature, the capacitance and dielectric loss of the sample are reduced by 1 Vr.
ms, 1 KHz, and the dielectric constant was determined from the capacitance. On the other hand, the signal voltage characteristic of the dielectric loss was measured by applying a 1 KHz signal at 50 Vrms / mm . The following (Table 2)
Sintering density at 1300 ° C and 1330 ° C,
Dielectric constant at room temperature at 330 ° C. firing, dielectric loss, the signal voltage characteristic of the dielectric loss shown. In Tables 1 and 2, samples marked with # are out of the scope of the present invention and are comparative examples.

[0012]

[Table 1]

[0013]

[Table 2]

[0014] (Table 1), a lanthanum oxide with respect to As is apparent, 100 parts by weight of barium titanate from (Table 2)
Improved sinterability by adding 0.05 parts by weight or more
Is done. However, the added amount exceeds 0.50 parts by weight
And the dielectric constant is significantly reduced, while less than 0.05 parts by weight.
Is not included in the scope of claims because it does not have the effect of improving sinterability
did.

In this embodiment, the manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 2 This example also corresponds to the first aspect of the present invention, and a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment are added. Nickel oxide,
The problem has been solved by adding manganese oxide and further adding cerium oxide .

First, a particle size of 0.1 produced by the hydrothermal synthesis method is used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. With respect to 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted into Nb ₂ O ₅ , nickel oxide is converted into NiO, manganese oxide is converted into MnO ₂ , and cerium oxide is converted into CeO _2. The amount shown in (Table 3) was weighed.
Also in Table 3, niobium pentoxide, nickel oxide, manganese oxide, and cerium oxide are simply referred to as Nb, Ni, Mn , and C , respectively.
e . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

At 1300 ° C. and 1330 ° C.
5 shows the sintering density at ℃ firing, the dielectric constant at room temperature at 1330 ° firing, the dielectric loss, and the signal voltage characteristics of the dielectric loss. In Tables 3 and 4, samples marked with # are out of the scope of the present invention and are comparative examples.

[0019]

[Table 3]

[0020]

[Table 4]

As apparent from Tables 3 and 4, sinterability is improved by adding cerium oxide in an amount of 0.05 part by weight or more to 100 parts by weight of barium titanate. However, when the addition amount exceeds 0.50 parts by weight, the dielectric constant is remarkably reduced, and when the addition amount is less than 0.05 parts by weight, the effect of improving the sinterability is not obtained, and therefore, it is excluded from the claims.

In this embodiment, the manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 3 This example also corresponds to the first aspect of the present invention, and a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment. Nickel oxide,
The problem has been solved by adding manganese oxide and further adding neodymium oxide .

First, a particle diameter of 0.1 produced by the hydrothermal synthesis method is used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted into Nb ₂ O ₅ , nickel oxide is converted into NiO, manganese oxide is converted into MnO ₂ , and neodymium oxide is converted into Nd ₂ O.
_The amounts shown in the following (Table 5) were weighed in _three conversions. In Table 5, niobium pentoxide, nickel oxide, manganese oxide, and neodymium oxide are simply referred to as Nb, Ni, and M, respectively.
n and Nd . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

The following (Table 6) shows 1300 ° C. and 1330 ° C.
5 shows the sintering density at ℃ firing, the dielectric constant at room temperature at 1330 ° firing, the dielectric loss, and the signal voltage characteristics of the dielectric loss. In Tables 5 and 6, samples marked with # are out of the scope of the present invention and are comparative examples.

[0026]

[Table 5]

[0027]

[Table 6]

As is clear from Tables 5 and 6, sinterability is improved by adding 0.05 parts by weight or more of neodymium oxide to 100 parts by weight of barium titanate. However, when the addition amount exceeds 0.50 parts by weight, the dielectric constant is remarkably reduced, and when the addition amount is less than 0.05 parts by weight, the effect of improving the sinterability is not obtained, and therefore, it is excluded from the claims.

In this embodiment, the manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 4 This example also corresponds to the first aspect of the present invention, in which a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment are added to barium titanate. Nickel oxide,
The problem was solved by adding manganese oxide and further adding samarium oxide .

First, a particle size of 0.1 produced by the hydrothermal synthesis method is used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted into Nb ₂ O ₅ , nickel oxide is converted into NiO, manganese oxide is converted into MnO ₂ , and samarium oxide is converted into Sm ₂ O.
_The amounts shown in the following (Table 7) were weighed in _three conversions. Also in Table 7, niobium pentoxide, nickel oxide, manganese oxide, and samarium oxide were simply referred to as Nb, Ni, and M, respectively.
n and Sm . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

The following (Table 8) shows 1300 ° C. and 1330 ° C.
5 shows the sintering density at ℃ firing, the dielectric constant at room temperature at 1330 ° firing, the dielectric loss, and the signal voltage characteristics of the dielectric loss. In Tables 7 and 8, samples marked with # are out of the scope of the present invention and are comparative examples.

[0033]

[Table 7]

[0034]

[Table 8]

As is clear from Tables 7 and 8, the sinterability is improved by adding 0.05 parts by weight or more of samarium oxide to 100 parts by weight of barium titanate. However, when the addition amount exceeds 0.50 parts by weight, the dielectric constant is remarkably reduced, and when the addition amount is less than 0.05 parts by weight, the effect of improving the sinterability is not obtained, and therefore, it is excluded from the claims.

In this embodiment, manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 5 This example also corresponds to the first aspect of the present invention, in which a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment are added. Nickel oxide,
The problem was solved by adding manganese oxide and further adding dysprosium oxide .

First, a particle size of 0.1 produced by the hydrothermal synthesis method is used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted to Nb ₂ O ₅ , nickel oxide is converted to NiO, manganese oxide is converted to MnO ₂ , and dysprosium oxide is converted to D.
The amount shown in the following (Table 9) in terms of y ₂ O ₃ was weighed. Also in Table 9, niobium pentoxide, nickel oxide, manganese oxide, and dysprosium oxide were simply referred to as Nb and N, respectively.
i, Mn, and Dy . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

The following (Table 10) shows that at 1300 ° C. and 133 ° C.
The sintering density at 0 ° C. firing, the dielectric constant at room temperature at 1330 ° C. firing, dielectric loss, and signal voltage characteristics of dielectric loss are shown. In Tables 9 and 10, the samples marked with # are out of the scope of the present invention and are comparative examples.

[0040]

[Table 9]

[0041]

[Table 10]

As apparent from (Table 9) and (Table 10),
Dysprosium oxide to 100 parts by weight of barium titanate
By further addition of um or 0.05 parts by weight,
Sinterability is improved. However, when the addition amount exceeds 0.50 parts by weight, the dielectric constant is remarkably reduced, and when the addition amount is less than 0.05 parts by weight, the effect of improving the sinterability is not obtained, and therefore, it is excluded from the claims.

In this embodiment, the manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 6 This example also corresponds to the first aspect of the present invention, in which a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment are added. Nickel oxide,
The problem has been solved by adding manganese oxide and further adding yttrium oxide .

First, a particle size of 0.1 produced by the hydrothermal synthesis method was used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of the above barium titanate, niobium pentoxide is converted to Nb ₂ O ₅ , nickel oxide is converted to NiO, manganese oxide is converted to MnO ₂ , and yttrium oxide is converted to Y.
The amounts shown in Table 11 below were weighed in terms of b ₂ O ₃ . (Table 11) also shows niobium pentoxide, nickel oxide,
Manganese oxide and ytterbium oxide are simply N
b, Ni, Mn, and Yb . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

The following (Table 12) shows that at 1300 ° C. and 133
The sintering density at 0 ° C. firing, the dielectric constant at room temperature at 1330 ° C. firing, dielectric loss, and signal voltage characteristics of dielectric loss are shown. In Tables 11 and 12, samples marked with # are out of the scope of the present invention and are comparative examples.

[0047]

[Table 11]

[0048]

[Table 12]

As is clear from Table 11 and Table 12, it was oxidized with respect to 100 parts by weight of barium titanate.
The sinterability is improved by further adding 0.05 % by weight or more of rivium . However, when the amount added is 0.5
When the amount exceeds 0 parts by weight, the dielectric constant is remarkably reduced.
If the amount is less than 5 parts by weight, the effect of improving the sinterability is not obtained, so that it is excluded from the claims.

In this embodiment, the manganese oxide is MnO ₂
However, it may be added in other forms such as MnCO _3, and the same effect can be obtained as long as the amount of metal manganese is the same.

Example 7 This example also corresponds to the first aspect of the present invention, and a specific amount of niobium pentoxide and barium titanate produced by a hydrothermal synthesis method and having a specific surface area adjusted by heat treatment are added to the barium titanate. Nickel oxide,
The problem has been solved by adding manganese oxide and further adding praseosium oxide .

First, a particle size of 0.1 produced by the hydrothermal synthesis method was used.
A barium titanate fine powder having a purity of 99.99% or more is calcined at 1050 ° C. to have a specific surface area of 1.2 m ^2.
/ G of barium titanate was used. For 100 g (parts by weight) of barium titanate, niobium pentoxide is converted to Nb ₂ O ₅ , nickel oxide is converted to NiO, manganese oxide is converted to MnO ₂ , and praseosium is converted to P.
The amount shown in the following (Table 13) in terms of r ₂ O ₃ was weighed. (Table 13) also shows niobium pentoxide, nickel oxide,
Manganese oxide and praseosium oxide are simply N
b, Ni, Mn, and Pr . Or less (Example 1) and work-made samples by the same procedure, was evaluated.

The following (Table 14) shows that at 1300 ° C. and 133
The sintering density at 0 ° C. firing, the dielectric constant at room temperature at 1330 ° C. firing, dielectric loss, and signal voltage characteristics of dielectric loss are shown. In Tables 13 and 14, samples marked with # are out of the scope of the present invention and are comparative examples.

[0054]

[Table 13]

[0055]

[Table 14]

As is apparent from Tables 13 and 14, 100 parts by weight of barium titanate was used to produce oxide placebo.
By further adding 0.05 part by weight or more of osmium, sinterability is improved. However, when the amount added is 0.5
When the amount exceeds 0 parts by weight, the dielectric constant is remarkably reduced.
If the amount is less than 5 parts by weight, the effect of improving the sinterability is not obtained, so that it is excluded from the claims.

In each of the above embodiments, the additive was
Lanthanum oxide, cerium oxide, neodymium oxide, samarium oxide, dysprosium oxide, yttrium oxide,
Although the case where one kind of praseosium oxide is added in an amount of 0.05 to 0.50 parts by weight based on 100 parts by weight of barium titanate is described, even if two or more of these additives are added simultaneously, The total amount of addition is 0.05-
Within the range of 0.50 parts by weight, the same effects as in the above embodiments can be obtained.

In each of the above embodiments, the manganese oxide is M
Although added as nO _2, it may be added in other forms such as MnCO _3, and the same effect can be obtained if the amount of metal manganese is the same.

[0059]

As described above, the dielectric porcelain composition of the present invention is 2800.
It has excellent characteristics such as a high dielectric constant up to about 4000, a small change in the dielectric constant with temperature, and a dielectric loss of 2.5% or less when a signal voltage of 50 Vrms / mm is applied. Therefore, it can be put to practical use as a dielectric material for a ceramic capacitor. In particular, in the case of a multilayer ceramic capacitor, the dielectric layer can be made thinner, so that miniaturization and large capacity can be easily realized.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-258610 (JP, A) JP-A-1-315904 (JP, A) JP-A-2-258671 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01B 3/12 303 C04B 35/46 H01G 4/12 358

Claims (1)

(57) [Claims] 1. A generated by the hydrothermal synthesis method, the I Ri specific surface area in the heat treatment on 0.8~2.4m ² / g 100 parts by weight of barium titanate adjusted to, niobium pentoxide 0.8 1.
5 parts by weight of nickel oxide and manganese oxide in a total amount of 0.
At least 1 part by weight and the weight ratio of niobium pentoxide, nickel oxide and manganese oxide is 3 ≦ niobium pentoxide / (nickel oxide + manganese oxide) (however, nickel oxide 0 parts by weight and manganese oxide 0 parts by weight are so that as the exception)
Lanthanum oxide, cerium oxide, neo oxide
Indium, samarium oxide, dysprosium oxide,
One or more of tritium and praseosium oxide
Is a dielectric porcelain composition obtained by adding 0.05 to 0.50 parts by weight .