KR20120110027A - Dielectric ceramic composition and electronic component - Google Patents

Abstract

PURPOSE: A dielectric magnetism ceramic composition and electronic component is provided to increase alternating current breakdown field and temperature characteristic of electrostatic capacity. CONSTITUTION: A dielectric magnetism ceramic composition has a main component marked as the composition expression of (BaxBiy)TiO3, a first minor component and a second minor component. In the composition expression, y is 0.001<=y<=0.010, and the total sum of y and x is 0.975<=x+y<=1.010. The first minor component is zinc oxide. The second minor component is one oxide selected from Y, La, Ce, Nd, Sm, Mn and Ni. The first minor component is contained 2-12 parts by weight based on 100 parts by weight of the main component. The second minor component is contained 0.008-0.08 part by weight based on 100 parts by weight of the main component. The dielectric ceramic composition is used in a dielectric layer of the electronic component. The electronic components manufactured by the composition include a ceramic condenser(2).

Description

Dielectric Ceramic Composition and Electronic Component {DIELECTRIC CERAMIC COMPOSITION AND ELECTRONIC COMPONENT}

TECHNICAL FIELD The present invention relates to dielectric ceramic compositions and electronic components.

Ceramic capacitors, which are examples of electronic components, are used in various electronic devices, and demand for higher performance is increasing.

Ceramic capacitors used as noise filters and Y capacitors in switching power supply circuits are constantly exposed to electrical stress, which may cause fire or electric shock. For this reason, the ceramic capacitor of safety standard approval is used in order to prevent this. As a ceramic capacitor with safety standards, it is most important that the ceramic capacitor is not destroyed, that is, the AC alternating electric field (ACVB) of the dielectric ceramic composition is high. Moreover, in these ceramic capacitors, it is also important to improve the temperature characteristics of the electrostatic capacitance, and it is preferable to make both the AC breakdown electric field and the temperature characteristics of the electrostatic capacitance compatible.

Patent Literatures 1 and 2 disclose dielectric ceramic compositions having a relatively high alternating current breaking field. However, the alternating current breakdown electric field of both is about 5 mA / mm. In addition, these documents do not disclose a dielectric ceramic composition in which the alternating current characteristics of the alternating electric field and the capacitance are compatible.

As the electrode of the ceramic capacitor, a baking electrode of Ag or Cu is used. Ag, however, can be baked in the atmosphere but is expensive. On the other hand, although Cu is inexpensive, it is necessary to make it a baking atmosphere, and since a capacitor | condenser element is exposed to reducing atmosphere, oxygen vacancies may increase and it may become semiconductor. For this reason, in order to prevent the semiconductorization of a capacitor | condenser element, patent document 3, for example, controls A / B composition of {Ba _(1-x) Ca _x } _A {Ti _(1-y) Zr _y } _B O ₃ . Is being done.

Patent Document 1: Japanese Patent Application Laid-Open No. 2006-096576 Patent Document 2: Japanese Patent Application Laid-Open No. 2003-104774 Patent Document 3: Japanese Patent Application Laid-Open No. 10-36170

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to provide a dielectric ceramic composition having a high alternating current breaking field, good temperature characteristics of capacitance, high dielectric constant and good reduction resistance. It is also an object of the present invention to provide an electronic component having a dielectric layer composed of such a dielectric ceramic composition.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, the present inventors discovered that the said objective can be achieved by making a composition of a dielectric ceramic composition into a specific component, and making these ratio into a predetermined range, and came to complete this invention.

That is, the dielectric ceramic composition according to the embodiment of the present invention for solving the above problems,

A dielectric ceramic composition having a main component represented by the composition formula of (Ba _x Bi _y ) TiO ₃ , a first sub component, and a second sub component,

Y in the composition formula is 0.001 ≦ y ≦ 0.010, and the sum of x and y in the composition formula is 0.975 ≦ x + y ≦ 1.010,

The first accessory ingredient is zinc oxide,

The second accessory ingredient is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn and Ni,

The first subcomponent is contained 2 parts by weight or more and 12 parts by weight or less based on 100 parts by weight of the main component,

The second accessory ingredient is a dielectric ceramic composition containing 0.008 parts by weight or more and 0.08 parts by weight or less in terms of oxide with respect to 100 parts by weight of the main component.

According to the present invention, it is possible to provide a dielectric ceramic composition having a high alternating current breakdown field, good electrostatic capacitance temperature characteristics, high relative dielectric constant and good reduction resistance.

The electronic component which concerns on embodiment of this invention has a dielectric layer comprised from the dielectric ceramic composition obtained by the said dielectric ceramic composition or the said manufacturing method.

Although it does not specifically limit as an electronic component which concerns on embodiment of this invention, A single plate type ceramic capacitor and a multilayer ceramic capacitor are illustrated.

1: (A) is a front view of the ceramic capacitor which concerns on one Embodiment of this invention, (B) is a side sectional view of the ceramic capacitor which concerns on one Embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on embodiment shown in drawing.

Ceramic Capacitors (2)

As shown in Figs. 1A and 1B, the ceramic capacitor 2 according to the embodiment of the present invention includes a dielectric layer 10, a pair of terminal electrodes 12 and 14 formed on the opposite surface thereof, And lead terminals 6 and 8 connected to the terminal electrodes 12 and 14, respectively, which are covered with the protective resin 4.

Although the shape of the ceramic capacitor | condenser 2 may be suitably determined according to an objective and a use, it is preferable that the dielectric layer 10 is a disk-shaped capacitor of disk shape. Moreover, what is necessary is just to determine size suitably according to an objective and a use, Usually, about 5-20 mm in diameter, Preferably it is about 5-15 mm.

Dielectric layer (10)

The dielectric layer 10 is comprised by the dielectric ceramic composition which concerns on embodiment of this invention.

The dielectric ceramic composition according to the embodiment of the present invention has a main component represented by the composition formula of (Ba _x Bi _y ) TiO ₃ , a first subcomponent, and a second subcomponent, and y in the composition formula is 0.001 ≦ y ≦ 0.010. In addition, the sum of x and y in the said composition formula is 0.975 <x + y <= 1.010.

In the above composition formula, x represents a ratio of Ba, and x is 0.965 ≦ x ≦ 1.009, preferably 0.976 ≦ x ≦ 0.996. By containing Ba in this range, the temperature characteristic of the electrostatic capacity becomes good, the dielectric constant improves and the sinterability tends to be good.

Y in the said composition formula represents the ratio of Bi, and is 0.001 <= y <= 0.010, Preferably it is 0.003 <= y <= 0.009. By containing Bi in this range, the temperature characteristic of the electrostatic capacity becomes good, and the dielectric constant tends to improve.

The sum of x and y in the above composition formula, that is, the sum of Ba and Bi ratios is preferably O.975 ≦ x + y ≦ 1.010, more preferably 0.976 ≦ x + y ≦ 1.005. By setting the total amount of x and y in this range, the sintering property and relative dielectric constant tend to be improved.

The first subcomponent is zinc oxide.

In the dielectric ceramic composition according to the embodiment of the present invention, the first subcomponent may be 2 parts by weight or more and 12 parts by weight or less, more preferably 2.5 parts by weight or more and 10 parts by weight or less, more preferably 100 parts by weight of the main component. 3 parts by weight or more and 10 parts by weight or less are contained. By containing a 1st subcomponent in this range, an alternating current breakdown electric field will improve and the temperature characteristic of an electrostatic capacitance will become favorable.

The second subcomponent is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn and Ni, preferably at least one oxide selected from Ce, Mn, and more preferably Mn Oxide.

In the dielectric ceramic composition according to the embodiment of the present invention, the second main component is 0.008 parts by weight or more and 0.08 parts by weight or less, more preferably 0.01 to 0.08 parts by weight, and even more preferably, in terms of oxide based on 100 parts by weight of the main ingredient. Contains 0.02 to 0.08 parts by weight. By containing a 2nd subcomponent in this range, an alternating current breakdown electric field improves and it becomes the tendency for the temperature characteristic of an electrostatic capacitance to become favorable, and reduction resistance will become favorable.

The dielectric ceramic composition according to the embodiment of the present invention preferably contains less than 1.0 part by weight of zirconium oxide with respect to 100 parts by weight of the main component, more preferably 0 parts by weight or more and 0.5 parts by weight or less, and even more preferably. Is 0 parts by weight. When zirconium oxide contains more than this range, there exists a tendency for an alternating current breakdown electric field to fall.

Although the thickness of the dielectric layer 10 is not specifically limited, What is necessary is just to determine suitably according to a use etc., Preferably it is 0.3-2 mm. By setting the thickness of the dielectric layer 10 to such a range, it can be used suitably for a high pressure application.

Terminal electrodes 12, 14

The terminal electrodes 12 and 14 are made of a conductive material. Examples of the conductive material used for the terminal electrodes 12 and 14 include Cu, Cu alloys, Ag, Ag alloys, In-Ga alloys, and the like. On the other hand, when Cu or a Cu alloy is used for the electrically conductive material of a terminal electrode conventionally, since baking of a terminal electrode needs to be performed in a reducing atmosphere, there exists a possibility that a dielectric ceramic composition may semiconductor. However, because the dielectric ceramic composition according to the embodiment of the present invention has good reduction resistance, even when Cu or a Cu alloy is used for the terminal electrode, the dielectric ceramic composition can be prevented from burning.

Manufacturing method of ceramic capacitor

Next, the manufacturing method of a ceramic capacitor is demonstrated.

First, the dielectric ceramic composition powder which forms the dielectric layer 10 shown in FIG. 1 after baking is manufactured.

The raw material of a main component and the raw material of a 1st subcomponent and a 2nd subcomponent are prepared. Examples of the raw material of the main component include Ba, Bi and Ti oxides and / or raw materials which become oxides by firing, composite oxides thereof, and the like, and examples thereof include BaCO ₃ , Bi ₂ O ₃ , and TiO ₂ . It is available. In addition, for example, various compounds such as hydroxides, which become oxides or titanium compounds after firing, may be used. In this case, what is necessary is just to change content suitably so that the number of elements of a metal element may match.

In addition, although the raw material of a main component may be manufactured by the solid-phase method, and may be manufactured by liquid phase methods, such as a hydrothermal synthesis method and an oxalate method, by the solid-phase method from a manufacturing cost point of view, It is preferable to prepare.

It does not specifically limit as a raw material of a 1st subcomponent and a 2nd subcomponent, The various compounds which become these oxides or complex oxides by the above-mentioned oxide and complex oxide of each subcomponent, or baking, for example, carbonate, nitrate, hydroxide, organic It can select from a metal compound suitably, and can use.

In the method for producing a dielectric ceramic composition according to an embodiment of the present invention, first, a raw material of a main component or a raw material of a main component and a raw material of a subcomponent are blended and wet-mixed using a ball mill made of zirconia balls or the like.

A plastic powder can be obtained by granulating the obtained mixture and plasticizing the obtained molded product in an air atmosphere. As plasticity conditions, plasticity temperature becomes like this. Preferably it is 1100-1300 degreeC, More preferably, 1150-1250 degreeC, Plasticity time should just be 0.5 to 4 hours.

Subsequently, the obtained plastic powder is wet-pulverized by a ball mill or the like, mixed and dried again to obtain a dielectric ceramic composition powder. As described above, by producing the dielectric ceramic composition powder by the solid phase method, the manufacturing cost can be reduced while realizing desired characteristics.

Subsequently, an appropriate amount of binder is added to the obtained dielectric ceramic composition powder and granulated, and the obtained granulated product is molded into a disk having a predetermined size to obtain a green molded body. Then, by firing the obtained green molded body, a sintered body of the dielectric ceramic composition is obtained. On the other hand, although it does not specifically limit as baking conditions, Preferably a holding temperature is 1200-1400 degreeC, More preferably, it is 1250-1350 degreeC, and it is preferable to make baking atmosphere into air.

The terminal electrodes are printed on the main surface of the obtained sintered body of the dielectric ceramic composition and baked as necessary to form the terminal electrodes 12 and 14. Thereafter, the lead terminals 6 and 8 are joined to the terminal electrodes 12 and 14 by soldering or the like, and finally, the element body is covered with the protective resin 4 to thereby be connected to FIGS. 1A and 1B. The single plate ceramic capacitor as shown is obtained.

The ceramic capacitor of the present invention thus produced is mounted on a printed board or the like via the lead terminals 6 and 8 and used for various electronic devices.

As mentioned above, although embodiment of this invention was described, this invention is not limited at all to this embodiment, Of course, it can be implemented in various other form within the range which does not deviate from the summary of this invention.

For example, in the above embodiment, as the electronic component according to the present invention, a single-layer ceramic capacitor having a single dielectric layer is exemplified, but the electronic component according to the present invention is not limited to a single-plate ceramic capacitor. A multilayer ceramic capacitor may be produced by a conventional printing method or sheet method using a dielectric paste and an electrode paste containing.

<Examples>

Hereinafter, the present invention will be described based on more detailed examples. However, the present invention is not limited to these examples.

Samples 1-40

BaCO ₃ , Bi ₂ O ₃ Ti0 ₂ and the second subcomponent were prepared as raw materials of the main component, respectively. And these prepared raw materials were each weighed so that it might become the composition shown to the sample 1-40 of Table 1, and it wet-mixed by the ball mill by the zirconia ball which used pure water as a solvent.

Subsequently, the obtained mixture was dried, then granulated and molded by adding 5% by weight of water. And the obtained molding was plasticized on condition of 1150 degreeC and 2 hours in air. The powder after plasticity was coarsely pulverized with a mixer and passed through a mesh pass. Then, the first sub ingredient (ZnO) was weighed and added so as to have the composition shown in Table 1, and wet grinding was performed. By drying this, the dielectric ceramic composition powder which has each composition shown in Table 1 (each composition of samples 1-40) was obtained.

10 parts by weight of an aqueous polyvinyl alcohol solution was added to 100 parts by weight of the obtained dielectric ceramic composition powder, and then granulated and passed through a mesh path. The resulting granulated powder was molded at a pressure of 396 MPa, having a diameter of 16.5 mm and a thickness of about 1.2 mm. The disk-shaped green molded object was obtained.

The obtained green molded body was baked in the air at 1250-1350 degreeC on the conditions of 2 hours, and the disc shaped sintered compact was obtained.

And the Ag electrode was apply | coated to both surfaces of the main surface of the obtained sintered compact, and it baked again in air for 20 minutes at 650 degreeC, and obtained the disk shaped ceramic capacitor sample as shown in FIG. The thickness of the dielectric layer 10 of the obtained capacitor sample was about 1 mm, and the diameter of the baking electrode was 12 mm.

In addition, in some of the obtained sintered compacts, in order to measure the absolute value of the dielectric loss change amount, Cu electrode is apply | coated to both surfaces of a main surface, and baking process is performed for 10 minutes at 800 degreeC in reducing atmosphere, as shown in FIG. A sample of a disk-shaped ceramic capacitor was obtained. The thickness of the dielectric layer 10 of the obtained capacitor sample was about 1 mm, and the diameter of the baking electrode was 12 mm.

And about each obtained capacitor | condenser sample, the temperature characteristic of the alternating current breakdown electric field, relative dielectric constant, and electrostatic capacitance was evaluated by the following method, respectively. The evaluation results are shown in Table 1.

(ACVB)

AC breakdown electric field (ACVB) measured the electric field value at the time when a 100 mA leakage current flowed by gradually applying an alternating electric field to 100 V / s with respect to the sample of a capacitor | condenser, and measured it as an alternating current breaking electric field. It is preferable that the alternating current breakdown electric field is higher, and in this embodiment, 6.0 mA / mm or more is considered to be good.

(Dielectric constant (ε))

The relative dielectric constant ε was calculated from the capacitance measured under a condition of a frequency of 1 Hz and an input signal level (measured voltage) of 1.0 Vrms with a digital LCR meter (4274A manufactured by Agilent Technologies) at a reference temperature of 20 ° C for a capacitor sample. none). It is preferable that the dielectric constant is higher, and 1500 or more is considered to be good in the present embodiment.

(% Of change in dielectric loss)

The dielectric loss of the capacitor sample with the Ag electrode and the dielectric loss of the capacitor sample with the Cu electrode are measured at a frequency of 1 Hz with a digital LCR meter (4274A manufactured by Agilent Technologies Inc.) at a reference temperature of 20 ° C., respectively, and the input signal level (measured voltage) 1.0. Measurement was made under the condition of Vrms.

Then, the dielectric loss of the capacitor sample having the Ag electrode is 'tan δ (Ag)' and the dielectric loss of the capacitor sample having the Cu electrode is 'tan δ (Cu)', and the amount of change in the dielectric loss represented by the following formula (1) The absolute value (%) was calculated.

| tanδ (Cu) -tanδ (Ag) | ... (One)

The absolute value of the change in dielectric loss is an index of reduction resistance, and a smaller value means better reduction resistance. In this example, 0.7 or less was considered good.

(Temperature Characteristics of Electrostatic Capacity)

For the capacitor samples, the capacitance was measured in the temperature range of -25 ° C to 85 ° C, and the rate of change of the capacitance at -25 ° C and 85 ° C (unit:%) relative to the capacitance at 20 ° C was calculated. In the present embodiment, it was assumed that the rate of change in capacitance was between -15% and 15%.

From Table 1, the following items were confirmed.

From Samples 2 to 4, 6 to 16, 18, and 19, the second subcomponent is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn, and Ni, and the second subcomponent is 100 wt% of the main component. In the case of 0.008 parts by weight or more and 0.08 parts by weight or less (parts 2 to 4, 6 to 7, 11 to 16, 19) in terms of oxide, the second accessory ingredient is Gd (sample 8) and Dy (sample 9). ), The reduction in dielectric loss is lower than in the case of Fe (sample 10) and Co (sample 18), so that the reduction resistance is good, and in particular, the AC breakdown as compared with the case of Fe (sample 10) It was confirmed that the electric field increased.

From Samples 1 to 4, 6 to 7, 11 to 16, 19, the second subcomponent is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn, and Ni, and the second subcomponent is the main component. When 0.008 weight part or more and 0.08 weight part or less are contained (samples 2-4, 6, 11-16, 19) with respect to 100 weight part, content of the said 2nd subcomponent is 100 weight part of said main components It was confirmed that the reduction resistance was good because the absolute value of the change in dielectric loss was lower than that in the case of O parts by weight (sample 1) in terms of oxide.

From Samples 2 to 7, 11 to 17, 19, the second accessory ingredient is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn, and Ni, and the second accessory ingredient is contained in 100 parts by weight of the main ingredient. When 0.008 parts by weight or more and 0.08 parts by weight or less are contained (samples 2 to 4, 6, 11 to 16, 19), the content of the second subcomponent is 0.10 in terms of oxide relative to 100 parts by weight of the main component. Compared with the weight part (samples 5 and 17), it was confirmed that an alternating current breakdown electric field was high, and especially, compared with the sample 5, the absolute value of the dielectric loss change amount and the temperature characteristic of the electrostatic capacitance became favorable.

When the content of zinc oxide is 2 parts by weight or more and 12 parts by weight or less (samples 31 to 36, 38 to 40) from the samples 30 to 40, the alternating current breakdown electric field is higher than that in this range (samples 30 and 37). I could confirm that.

When the sum of x and y in a composition formula is 0.975 <= x + y <= 1.010 from the samples 21-24, 26-29 (samples 21-24, 26, 29), when the sum of x and y is out of this range Compared with (Samples 27 and 28), it was confirmed that it was possible to sinter densely and that the temperature characteristics of the electrostatic capacitance were good.

From samples 20 to 25, when y in the composition formula is 0.001 ≦ y ≦ 0.008 (samples 21 to 24), the temperature characteristics of the electrostatic capacitance are better than when the y is out of this range (samples 20 and 25), and It was confirmed that the relative dielectric constant is high.

Claims (2)

A dielectric ceramic composition having a main component represented by the composition formula of (Ba _x Bi _y ) TiO ₃ , a first sub component, and a second sub component,
Y in the composition formula is 0.001 ≦ y ≦ 0.010, and the sum of x and y in the composition formula is 0.975 ≦ x + y ≦ 1.010,
The first accessory ingredient is zinc oxide,
The second accessory ingredient is at least one oxide selected from Y, La, Ce, Nd, Sm, Mn and Ni,
The first subcomponent is contained 2 parts by weight or more and 12 parts by weight or less based on 100 parts by weight of the main component,
The second accessory ingredient is 0.008 parts by weight or more and 0.08 parts by weight or less in terms of oxide based on 100 parts by weight of the main component. An electronic component having a dielectric layer composed of the dielectric ceramic composition according to claim 1.

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