JP2003146748A - Dielectric ceramic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric ceramic composition which has excellent microwave characteristics and low loss. SOLUTION: In the composition, the main components are expressed by the general formula of xBaO.yTiO2 .(z-z1 -z2 )SmO3/2 .z1 CeO2 .z2 PrO11/6 (wherein, 7<=x<=17, 57<=y<=63, 23<=z<=33, 0<z1 <=12, and 0<z2 <=12, and the relation of x+y+z=1 is satisfied), and, to the main components, as sub components, Bi2 O3 , CuO, ZnO, and B2 O3 are contained by 5.0 to 25 wt.% in total.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material such as a dielectric resonator, and more particularly, it has a large relative permittivity ε _r , a large no-load Q value, stable temperature characteristics, and silver or copper. The present invention relates to a dielectric ceramic composition having low-temperature sinterability capable of being co-fired with the internal electrode material.

[0002]

2. Description of the Related Art In recent years, miniaturization of equipment has been demanded with the development of communication technology utilizing electromagnetic waves in the microwave range, such as car phones, mobile phones and satellite broadcasting. For this purpose, it is necessary to reduce the size of individual parts that make up the device.

Dielectric ceramic compositions are used as materials for resonators, filters, multilayer capacitors, etc. in these microwave devices. For example, when used in resonators, filters, etc., when the same resonance mode is used, its size is inversely proportional to the square root of the dielectric constant of the dielectric material. A dielectric material having is required. It is also necessary to have a low dielectric loss in order to obtain excellent electrical characteristics. As the evaluation of the dielectric loss, Q defined by Q = 1 / tan δ is used, and it is required for the dielectric material that this Q is large. Further, the temperature coefficient τ _f is required to be as close to zero as possible in order to suppress the temperature change of the resonance frequency of the resonator and the filter.

In order to reduce the size of these electronic components, it has been attempted to obtain a laminated electronic component obtained by simultaneously firing a laminated structure of ceramics and internal electrodes. Since such a multilayer electronic component uses an electrode material having a low melting point and a small resistance loss, such as silver or copper, and is fired at the same time as the dielectric material, 100% is used as the dielectric material.
It must be a material that can be sintered at a temperature of 0 ° C or lower.

Conventionally, an inductor having a dielectric constant of about 60 to 90 is used.
As an electric material, BaO-Sm_TwoO _Three-TiO_TwoBased on
A microwave dielectric material having the present composition (Japanese Patent Laid-Open No. 59-19).
No. 1204) or a product obtained by adding an additive thereto,
Ruiha is BaO- (Sm_TwoO_Three, RE_TwoO_Three) -TiO
_TwoIt is known that the basic composition is (RE: rare earth element)
(JP-A-63-297265, JP-A-64)
-21811). Besides, Nd (OH)_ThreeOut
Dielectric material used as starting material, BaO- (Nd, Sm, B
i)_TwoO_Three-TiO_TwoOf the basic composition (JP-A-6-2751
No. 26), a dielectric material and the like are known.

[0006]

However, the dielectric materials disclosed in Japanese Patent Laid-Open Nos. 63-297265 and 64-21811 have a dielectric constant ε _r of 75.
-88, Q is 1800 or more at a resonance frequency of 3 to 6 GHz, and the temperature coefficient τ _f of the resonance frequency is -15 to 30, which is excellent in material properties, but the firing temperature is 1200 to 1500 ° C.
And high. Therefore, there is a problem that simultaneous firing cannot be performed using an electrode material having a low melting point such as silver or copper.

According to the present invention, ε _r is large, Q is large, and τ
_An object of the present invention is to provide a dielectric ceramic composition having a small _f and capable of being fired at a low temperature of 1000 ° C. or lower.

[0008]

In the present invention, the main component is generally
Formula xBaO ・ yTiO_Two・ (Z−z₁−z_Two) SmO_3/2・
z₁CeO_Two・ Z_TwoPrO_11/6(However, 7 ≦ x ≦ 17,
57 ≦ y ≦ 63, 23 ≦ z ≦ 33, 0 <z₁≦ 12, 0 <z
_Two≦ 12, x + y + z = 100)
Bi as a sub-component with respect to the main component_TwoO_Three, C
uO, ZnO, B _TwoO_ThreeIn a total amount of 5.0 to 25% by weight
It is a dielectric ceramic composition.

In the present invention, A is used with respect to the main component.
You may contain g 1.0 wt% or less. And Bi_Two
O_Three, CuO, ZnO, B_TwoO_ThreeRespectively Bi_TwoO
_Three1.0 to 10% by weight, CuO 2.0 to 5.0% by weight,
ZnO 1.0-9.0 wt%, B _TwoO_ThreeTo 1.0 to 5.0
It is preferably in the range of% by weight.

In the present invention, ε _r is as high as 60 or more and the absolute value of τ _f is 30 ppm due to the above specific composition.
/ ° C or less, Q is 500 or more, and 1000 ° C
It is possible to obtain a dielectric ceramic composition that can be sintered at the following temperatures. Therefore, the dielectric ceramic composition of the present invention can be integrally sintered by using a metal material having high conductivity such as silver or copper as an internal electrode. Therefore, it is possible to suppress the loss due to the high Q of the dielectric material and the electric resistance of the internal electrode, and to construct a microwave electronic component with extremely small loss. As a result, excellent microwave characteristics and low loss can be realized by applying to a dielectric resonator, a filter, a multilayer capacitor, or the like.

The above-mentioned dielectric properties such as ε _r , τ _f , and Q, and low-temperature sinterability are greatly influenced by the composition of the dielectric ceramic composition. If the main component composition of the dielectric ceramic composition of the present invention deviates from the above composition range of the present invention, the following problems will occur.

First, when the composition amount of BaO represented by x is less than 7 mol%, ε _r and Q are lowered and 10
Sintering below 00 ° C becomes difficult. On the other hand, if it is more than 17 mol%, ε _r becomes large and the low temperature sinterability is improved, but the Q is lowered. Therefore, x is 7 mol% to 17 mol%
Is desirable. Preferably 12 mol% to 15
It is mol%.

Further, the composition amount of TiO _{2 represented by} y is 57
When it is less than mol%, ε _r and Q decrease and τ _f
Becomes larger on the plus side. On the other hand, if it is more than 63 mol%, ε _r and Q are lowered and the low temperature sinterability becomes difficult. Therefore, y is preferably 57 mol% to 63 mol%. It is preferably from 59 mol% to 61 mol%.

Further, the composition amount of CeO _{2 represented} by z ₁ is 0.
When it is mol%, Q becomes less than 500 and low-temperature sinterability becomes difficult. If it is more than 12 mol%,
As ε _r decreases, τ _f increases toward the plus side. Therefore, z ₁ is preferably 12 mol% or less (excluding 0 mol%). Preferably 2 mol% to 10 mol%
Is.

When the composition amount of PrO 11/6 _represented by z ₂ is 0 mol%, Q becomes less than 500 and low temperature sinterability becomes difficult. On the other hand, _{if it} is more than 12 mol%, τ _f becomes large on the plus side. Therefore, z ₂ is preferably 12 mol% or less (excluding 0 mol%). It is preferably 2 mol% to 10 mol%.

The composition amount of SmO _3/2 is z-z ₁ -z.
Represented by _2, but when z is less than 23 mol%, Q is lowered, it becomes difficult to sinter at 1000 ° C. or less. Also,
When it is more than 33 mol%, ε _r and Q are lowered. Therefore, z is preferably 23 mol% to 33 mol%.
Preferably, it is 25 mol% to 28 mol%.

If the composition of the subcomponents in the dielectric ceramic composition of the present invention deviates from the above range, the following problems will occur.

First, when Bi ₂ O ₃ is less than 1.0% by weight with respect to the main component, ε _r is lowered and low temperature sinterability becomes difficult. If it is more than 10% by weight, ε _r
Is increased and the low temperature sinterability is improved, but Q is less than 500, which causes deterioration of dielectric properties, which is not preferable. Therefore, Bi ₂ O ₃ is 1.0% by weight to the main component.
It is preferably 10% by weight. Preferably, it is 5.0% by weight to 10% by weight.

Further, CuO is 2.0% by weight with respect to the main component.
If it is less than 1, the low temperature sinterability is difficult. Also, 5.0
When it is more than wt%, Q is less than 500, which causes deterioration of dielectric properties, which is not preferable. For this reason,
CuO is preferably 2.0 to 5.0% by weight with respect to the main component. Preferably, 3.0% by weight to 5.0% by weight
Is.

ZnO is 1.0% by weight based on the main component.
If it is less than Q, Q is lowered and low-temperature sinterability is difficult. On the other hand, if it is more than 9.0% by weight, ε _r decreases. Therefore, ZnO is 1.0 wt% to the main component.
It is preferably 9.0% by weight. Preferably 3.0
% By weight to 6.0% by weight.

B ₂ O ₃ is 1.0% by weight based on the main component.
If it is less than 1, the low temperature sinterability is difficult. Also, 5.0
When it is more than wt%, ε _r is less than 60 and Q is less than 500, which causes deterioration of dielectric properties, which is not preferable. Therefore, B ₂ O ₃ is 1.0 wt% to the main component.
It is preferably 5.0% by weight. Preferably 1.0
% By weight to 3.0% by weight.

Further, when Ag is added to the above subcomponent composition, ε _r becomes large and the low temperature sinterability is improved.
If it is more than 1.0% by weight with respect to the main component, Q will decrease. Therefore, Ag is preferably 1.0% by weight or less with respect to the main component.

[0023]

EXAMPLES Examples will be described in detail below.

Example 1 Starting materials are BaCO ₃ , TiO ₂ , Sm ₂ O ₃ , CeO ₂ and Pr ₆ having a purity of 99.9% or more.
O ₁₁ was used to weigh the compositional amount shown in Table 1, pure was added so that the slurry concentration was 40%, and the amount was 20 with a ball mill.
Wet mixed for hours and then dried. The dried powder was calcined at a temperature of 1000 to 1200 ° C. for 2 hours. The powder thus obtained is called a base material powder.

[0025]

[Table 1]

The asterisks * shown in Table 1 are comparative examples outside the scope of the present invention, and all other examples are examples within the scope of the present invention. Next, with respect to the base material powder obtained as described above, Bi ₂ O ₃ , CuO, ZnO, and B ₂ as auxiliary components were added.
O ₃ was weighed so as to be in the proportion shown in the sub-component composition column in Table 1, pure was added so as to have a slurry concentration of 40%, wet mixed in a ball mill for 20 hours, and then dried. 650-85 for this dried powder
Calcination was performed by holding at a temperature of 0 ° C. for 2 hours.

The calcined powder thus obtained was added with pure water to a slurry concentration of 40%, wet-milled for 16 to 24 hours in a ball mill, and then dried to obtain a dielectric ceramic composition (Sample 1). ~ 15) was obtained. The average particle size of the powder obtained as described above was adjusted to 0.5 to 2.0 μm.

Next, the granulated powder obtained by adding and kneading an aqueous binder solution to the dielectric ceramic composition obtained as described above was pressed at a pressure of ² ton / cm ² to obtain a molded body. This was fired in air at a temperature of 850 to 1050 ° C. for 2 hours to obtain a sintered body.

Next, a dielectric cylinder resonator was produced using the obtained sintered body, and the permittivity ε _r , Q and the temperature coefficient τ _f of the resonance frequency were measured by the Hacky-Coleman method.
The results are shown in Table 2.

[0030]

[Table 2]

The asterisks * shown in Table 2 are comparative examples outside the scope of the present invention, and all other examples are examples within the scope of the present invention. As shown in Table 2, the sample No. 10, 11
However, since it is out of the range of 7 ≦ x ≦ 17 and 23 ≦ z ≦ 33, a dense sintered body cannot be obtained at a firing temperature of 1000 ° C. or less, and Q cannot be 500 or more. In addition, the sample No. In Nos. 12 and 13, since it is out of the range of 57 ≦ y ≦ 63, a dense sintered body cannot be obtained at a firing temperature of 1000 ° C. or less, and Q cannot be 500 or more. In addition, the sample No. For 14 and 15, 0 <z ₁ ≤ 1
1000 ° C for out of the range of _2, 0 <z ₂ ≦ 12
A dense sintered body cannot be obtained at the following firing temperatures.
In the examples within the scope of the present invention, it is possible to obtain a dense sintered body at a firing temperature of 1000 ° C. or less, a high dielectric constant ε _r of 60 or more, and an absolute value of τ _f of 30 ppm.
/ ° C or less and a value of Q of 500 or more can be obtained.

Example 2 Starting materials are BaCO ₃ , TiO ₂ , Sm ₂ O ₃ , CeO ₂ and Pr ₆ having a purity of 99.9% or more.
A predetermined amount of O ₁₁ in Table 3 was weighed, pure was added so as to have a slurry concentration of 40%, wet mixed in a ball mill for 20 hours, and then dried. 1 for this dried powder
Calcination was performed by holding at a temperature of 000 to 1200 ° C. for 2 hours.

Next, with respect to the base material powder obtained as described above, Bi ₂ O ₃ , CuO, ZnO and B as auxiliary components are added.
₂ O ₃ and Ag were weighed so that the proportions shown in the column of sub-component composition in Table 3 were respectively obtained, pure was added so as to have a slurry concentration of 40%, wet-mixed in a ball mill for 20 hours, and then, Dried. 65 for this dried powder
Calcination was performed by holding at a temperature of 0 to 850 ° C. for 2 hours. Note that when Bi ₂ O _{3 as} an accessory component is mixed in advance with the main component composition and contained in the base material powder, Q increases (pre-addition). The effect of increasing Q by the pre-addition of Bi ₂ O ₃ is exhibited even when a part of the total amount to be added is pre-added and the rest is added (post-added) to the base material powder together with other subcomponents.

[0034]

[Table 3]

The asterisks * shown in Table 3 are comparative examples outside the scope of the present invention, and all other examples are examples within the scope of the present invention. The calcined powder obtained in this manner was added with pure water so that the slurry concentration would be 40%, and the mixture was mixed with a ball mill 16
It was wet pulverized for -24 hours and then dried to obtain a dielectric ceramic composition (Samples 16 to 37). The average particle size of the powder obtained as described above was adjusted to 0.5 to 2.0 μm.

Next, the granulated powder obtained by adding and kneading an aqueous binder solution to the dielectric ceramic composition obtained as described above was pressed at a pressure of ² ton / cm ² to obtain a molded body. This was fired in air at a temperature of 850 to 1050 ° C. for 2 hours to obtain a sintered body.

Next, a dielectric cylinder resonator was produced using the obtained sintered body, and the dielectric constants ε _r and Q and the temperature coefficient τ _f of the resonance frequency were measured by the Hacky-Coleman method.
The results are shown in Table 4.

[0038]

[Table 4]

The mark * shown in Table 4 indicates a ratio outside the scope of the present invention.
Comparative examples, all other examples within the scope of the present invention
Is. As shown in Table 4, the sample No. 16 is a by-product
Minutes CuO, ZnO, B_TwoO_Three, Does not contain Ag
Therefore, the firing temperature becomes 1300 ° C and firing at 1000 ° C or less
A dense sintered body cannot be obtained at the forming temperature. Also try
Fee No. 17, 22, and 26 are Bi respectively_TwoO_ThreeBut
Less than 1.0 wt%, ZnO less than 1.0 wt%, CuO
Since it is less than 2.0% by weight, the firing temperature is 1000 ° C or less.
No dense sintered body could be obtained in the sample No. At 22
Causes Q to be less than 500, causing deterioration of dielectric properties.
You In addition, the sample No. 30, 36 and 37 are B_TwoO_ThreeBut
Since it is less than 1.0% by weight and Ag is more than 1.0% by weight, Q
Is less than 500, causing deterioration of dielectric properties,
Fee No. No. 30 is dense firing at a firing temperature of 1000 ° C or less.
I can't get a union. Examples within the scope of the invention
For both, dense sintering at a firing temperature of 1000 ° C or less
The body can be obtained and the permittivity ε _rIs higher than 60
Τ_fAbsolute value of 30ppm / ℃ or less, Q is 5
Values over 00 can be obtained.

[0040]

According to the present invention, as a dielectric ceramic composition for microwaves, a material that can be sintered at 1000 ° C. or lower, has a high dielectric constant ε _r of 60 or more, and has an absolute value of τ _f. Three
A dielectric material having a content of 0 ppm / ° C. or less and a Q of 500 or more can be obtained. This makes it possible to obtain excellent microwave characteristics and low loss as a microwave component such as a dielectric resonator for microwaves, a filter, and a multilayer capacitor. In particular, it is an excellent material for a laminated microwave component in which an internal circuit is formed by co-firing with an electrode material such as silver or copper.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4G031 AA06 AA07 AA11 AA25 AA26                       AA28 AA35 BA09                 5G303 AA01 AA02 AB05 AB15 CA01                       CB03 CB08 CB26 CB35 CB41                 5J006 HC07

Claims (3)

[Claims] 1. The main component is a general formula xBaO.yTiO._Two・
(Z−z₁−z_Two) SmO _3/2・ Z₁CeO_Two・ Z_TwoPrO
_11/6(However, 7 ≦ x ≦ 17, 57 ≦ y ≦ 63, 23 ≦
z ≦ 33, 0 <z₁≦ 12, 0 <z_Two≤12, x + y + z = 1
00)), and with respect to the main component,
Bi as an accessory ingredient_TwoO_Three, CuO, ZnO, B_TwoO_ThreeTo
Dielectrics characterized by containing 5.0 to 25% by weight in total
Body porcelain composition. 2. The dielectric ceramic composition according to claim 1, which contains 1.0 wt% or less of Ag with respect to the main component. 3. The dielectric ceramic composition according to claim 1 or 2, wherein Bi ₂ O ₃ is 1.0 to 10 wt%, CuO is 2.0 to 5.0 wt%, and ZnO is 1.0. ~ 9.0 wt%, B ₂
A dielectric ceramic composition containing O ₃ in a range of 1.0 to 5.0% by weight.