KR100406350B1 - Dielectric ceramic composition, ceramic capacitor using the composition and a process of producing same - Google Patents

Abstract

The present invention provides a dielectric ceramic composition, a magnetic capacitor using the same, and a method of manufacturing the same, which have a small size, a large capacity, a stable characteristic even in a high frequency region, and which can greatly reduce the manufacturing cost by realizing firing at a low temperature.

The dielectric ceramic composition of the present invention contains 20 to 80 mol% of TiO ₂ , and 0.5 to 20 wt% of CuO, 0.1 to 5 wt% of MnO ₂ , and Al ₂ O ₃ 0 in a main composition composed of residual ZnO and unavoidable impurities. ~ 5% by weight, Sb ₂ O ₃ 0.001-15% by weight, and 0.5 to 10% by weight of the glass composition is added.

Description

Dielectric ceramic composition, magnetic capacitor using same and method for manufacturing the same {Dielectric ceramic composition, ceramic capacitor using the composition and a process of producing same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric magnetic composition, a magnetic capacitor using the same, and a method of manufacturing the same. In particular, the present invention has excellent electrical characteristics such as high dielectric constant, low dielectric loss, and high insulation resistance in a high frequency region such as a microwave region. The present invention relates to a dielectric ceramic composition having excellent reliability and capable of significantly lowering the manufacturing cost by realizing firing at a low temperature, a magnetic capacitor using the same, and a method of manufacturing the same.

Conventionally, ceramic capacitors are well known as small and large capacity capacitors. The ceramic capacitor is a device using the dielectric properties of the ceramic, rutile (rutile) Type of TiO _2, the perovskite-type of _{BaTiO 3, MgTiO 3, CaTiO 3} , SrTiO 3 , such as a dielectric material to one or the other, or these in combination with the desired characteristics of the A capacitor with is obtained.

Ceramic capacitors are classified into single layer type and stacked type. Single-layer ceramic capacitors are press-molded the above-mentioned materials (powders) to form shaped articles such as pellets (plates), rods (cylindrical forms), chips (squares), and the like. After firing at a temperature of to form a sintered compact, it can be obtained by forming electrodes on both surfaces of the sintered compact.

In addition, the multilayer ceramic capacitor is a slurry obtained by kneading the above-described material (powder), an organic binder and an organic solvent. The slurry is formed into a sheet by a doctor blade method and degreased to form a green sheet. After printing an electrode made of a noble metal such as Pt or Pd on the green sheet, these sheets were stacked in the thickness direction and pressed to form a laminate, and the laminate was calcined at a temperature of 1200 to 1400 ° C to obtain a laminate. Can be.

By the way, in the above-described conventional ceramic capacitor, it is necessary to widen the application range in the high frequency region such as microwave, and to have higher characteristics and higher reliability with respect to characteristics such as relative dielectric constant, dielectric loss and insulation resistance. . Therefore, current dielectric materials do not reach their requirements sufficiently.

In particular, in the multilayer ceramic capacitor, it is necessary to bake at a temperature of 1200 to 1400 ° C. in order to obtain a compact laminate, and it is necessary to use precious metals such as Pt and Pd, which are stable even at a high temperature, to the internal electrode material. There was a difficult problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a small size, a large capacity, stable characteristics even in a high frequency range, and furthermore, a dielectric ceramic composition capable of significantly lowering the manufacturing cost by realizing firing at a low temperature, a magnetic capacitor using the same, and a method of manufacturing the same. The purpose is to provide.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the single-layer ceramic capacitor which is 1st Embodiment of this invention.

It is sectional drawing which shows the multilayer ceramic capacitor which is 2nd Embodiment of this invention.

* Description of the symbols for the main parts of the drawings *

Bulk dielectric 2 ..... Terminal electrode

3 ..... lead wire 4 ..... epoxy resin

11 ..... Dielectric layer 12 ..... Internal electrode

13, 14 ..... Terminal electrode

In order to solve the above problems, the present invention provides a dielectric magnetic composition, a magnetic capacitor using the same, and a method of manufacturing the same.

That is, the dielectric ceramic composition according to the present invention contains 20 to 80 mol% of TiO ₂ , and 0.5 to 20 wt% of CuO, 0.1 to 5 wt% of MnO ₂ , and Al ₂ to a cast product containing residual ZnO and unavoidable impurities. O ₃ 0 ~ 5 is the% by weight of Sb ₂ O ₃ 0.001 ~ 15% by weight, and the glass composition characterized by yirueojim by adding 0.5 to 10% by weight.

The dielectric magnetic composition contains 20 to 80 mol% of TiO ₂ , and 0.5 to 20 wt% of CuO, 0.1 to 5 wt% of MnO ₂ , and Al ₂ O ₃ 0 to 5 to a cast product containing residual ZnO and unavoidable impurities. By adding the weight%, 0.001 to 15% by weight of Sb ₂ O ₃ and 0.5 to 10% by weight of the glass composition, it is possible to realize electrical properties such as high dielectric constant, low dielectric loss, high insulation resistance, and the like. Electrical characteristics are stable in the high frequency range. This improves the reliability of the product in the high frequency region.

Here, the reason that the content of TiO ₂ is 20 to 80 mol% is that the dielectric loss increases at less than 20 mol%, so that the electrical properties are deteriorated in the high frequency region, and when it exceeds 80 mol%, the sinterability is lowered. Because it cannot be obtained.

In addition, the reason why the content of ZnO is remainder except TiO ₂ , that is, 20 to 80 mol%, is because a sinterability is lowered at less than 20 mol%, a dense sintered body cannot be obtained, and if it exceeds 80 mol%, the dielectric loss increases. This is because the electrical characteristics are deteriorated in the high frequency region.

CuO is added to improve dielectric loss, and the amount thereof is preferably 0.5 to 20% by weight. The reason is that the dielectric loss is not improved at less than 0.5% by weight, and if it exceeds 20% by weight, the dielectric loss is increased.

MnO ₂ is added to improve the dielectric loss, and the amount thereof is preferably 0.1 to 5% by weight. The reason is that the dielectric loss is not improved at less than 0.1% by weight, and if it exceeds 5% by weight, the dielectric loss is increased.

Al ₂ O ₃ is added to improve the dielectric loss, and the amount thereof is preferably 0 to 5% by weight. This is because the dielectric loss increases when it exceeds 5% by weight.

Sb ₂ O ₃ is added to improve the dielectric loss, and the amount thereof is preferably 0.001 to 15% by weight. The reason for this is that the dielectric loss can not be improved at less than 0.001% by weight, and if it exceeds 15% by weight, the dielectric loss is increased. In addition, the improvement effect of the dielectric loss mentioned above can be confirmed by measuring a tan (loss coefficient).

The glass composition is added as a sintering aid in order to improve the wettability in the grain boundary layer at the time of low temperature baking and to increase the sintering property, and the amount thereof is preferably 0.5 to 10% by weight. The reason for this is that a dense sintered body cannot be obtained because the effect as a sintering aid does not appear at less than 0.5% by weight, and if it exceeds 10% by weight, the dielectric loss increases.

Without adversely affecting the addition of the characteristic as the glass composition, the components of TiO _3, and ZnO and wetting of the primary composition well and, in addition, is more than 500 ℃ temperature glass to soften and / or melt are preferred.

In the dielectric magnetic composition according to the present invention, the glass composition is characterized in that the glass composition is any one of borate glass, borosilicate glass, zinc borate glass, zinc borosilicate glass, soft borate glass.

The magnetic capacitor is characterized in that the electrode is formed on both sides of the device consisting of the dielectric magnetic composition.

The magnetic capacitor is formed by alternately stacking a sheet-like dielectric layer and an electrode layer made of the dielectric magnetic composition.

The method for producing the dielectric ceramic composition includes 20 to 80 mol% of TiO ₂ , 0.5 to 20 wt% of CuO, 0.1 to 5 wt% of MnO ₂ , and Al ₂ O ₃ to a cast product containing residual ZnO and unavoidable impurities. 0 to 5% by weight, 0.001 to 15% by weight of Sb ₂ O ₃ , and 0.5 to 10% by weight of the glass composition were molded to form a bulk or sheet molded product, and the molded product was baked at a temperature of 800 ° C. or higher. It features.

This manufacturing method contains 20 to 80 mol% of TiO ₂ , 0.5 to 20% by weight of CuO, 0.1 to 5% by weight of MnO ₂ , and 0 to 5% by weight of Al ₂ O ₃ to a cast product containing residual ZnO and unavoidable impurities. , 0.001 to 15% by weight of Sb ₂ O ₃ , and 0.5 to 10% by weight of the glass composition were molded to form a bulk or sheet-shaped molded product, and the molded product was fired at a temperature of 800 ° C. or higher to form a glass composition as a sintering aid. In this firing process, the wettability of the grain boundary layer is improved, thereby adhering the powder particles in the molded body and simultaneously reducing the voids between the powder particles, thereby sintering. Thereby, it can bake at the temperature of 800 degreeC or more, and a compact high strength sintered compact can be obtained.

In the method for producing a dielectric ceramic composition according to the present invention, in the method for producing a dielectric ceramic composition, an electrode is formed on one main surface of the sheet-shaped molded body, and then the molded bodies are stacked and pressed in a plurality of thickness directions. To obtain a laminate, and the laminate is calcined at the above temperature.

In this manufacturing method, an electrode is formed on one main surface of a sheet-like molded article, and then the molded articles are stacked and pressed in a plurality of thickness directions to form a laminate, and the laminate is fired at the above temperature, whereby Pt or Pd is used as an internal electrode. Compared with noble metals, metals such as Ag and the like which are inexpensive can be used, and there is no need to use conventionally used noble metals such as Pt and Pd as electrode materials. As a result, lower cost can be achieved without lowering electrical characteristics such as high frequency characteristics.

Embodiments of the dielectric magnetic composition of the present invention, a magnetic capacitor using the same, and a method of manufacturing the same will be described with reference to the drawings.

[First Embodiment]

1 is a cross-sectional view showing a ceramic capacitor (magnetic capacitor) according to a first embodiment of the present invention, in which 1 is a bulk dielectric, 2 is a terminal electrode formed on both sides of the dielectric 1, and 3 is a terminal electrode ( Lead wire 4 connected to 2) is an epoxy resin for sealing them.

Dielectric (1) contains 20 to% 80 mol of TiO _2, and a week composition with the balance ZnO and unavoidable impurities, CuO 0.5 ~ 20 wt%, MnO ₂ 0.1 - 5 wt%, Al ₂ O ₃ 0 - 5 wt. %, Sb ₂ O ₃ 0.001 to 15 wt%, and a ceramic composition composed of a material composition to which 0.5 to 10 wt% of the glass composition is added.

The terminal electrode 2 is made of a metal mainly composed of Ag or Ag alloy. As the Ag alloy, for example, 90Ag-10Pd is preferably used.

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

First, the powdery TiO ₂ , ZnO, CuO, MnO ₂ , Al ₂ O ₃ , Sb ₂ O ₃ , and the glass compositions were weighed in predetermined amounts, respectively. Here, the basis weight was as shown in the material composition shown in Table 1.

Next, these powders are put into a ball mill together with a predetermined amount of a dispersion medium such as water (or an organic solvent such as ethanol or acetone), mixed and ground for a predetermined period of time, for example, 24 hours, and then dehydrated (or deethanol). And deorganic solvents such as acetone) were dried. Composition samples other than the material composition of this invention were also made into the comparative example (it shows with "*" in Table 1).

Subsequently, the dried powder was calcined at a temperature of 550 to 750 ° C for 0.5 to 5.0 hours, and then pulverized for 1 to 24 hours using Leicaigi (or automatic induction) to obtain a calcined powder having a predetermined particle size.

Next, after adding a predetermined amount of organic binders to this calcined powder, it was mixed and granulated uniformly using a Leica group or the like to obtain granulated powder (single granule) having a predetermined particle size. The organic binder was PVA (polyvinyl alcohol) aqueous solution. As the organic binder, an aqueous solution of ethyl cellulose, an acrylic resin solution (acrylic binder) and the like are preferably used in addition to the PVA aqueous solution.

Next, the granulated powder was molded into pellets having a diameter of 20 mm and a thickness of 2 mm using a molding machine, and then baked at a temperature of 800 ° C. or higher in the air for 0.5 to 10.0 hours to obtain a disc-shaped dielectric material 1 of the present embodiment. . In addition, the sample of the material composition of this invention was baked at the temperature other than the baking temperature range of this invention, and it was set as the comparative example (the comparative example is shown by "*" in Table 1).

Table 2 shows the electrical properties in each sample. In addition, in Table 2, the comparative example is shown by "*".

Here, the relative dielectric constant (ε) and tan δ (loss coefficient) were measured under conditions of 1 MHz and 1 Vrms at 25 ° C. Insulation resistance IR was measured after 1000 V (DC) was applied for 1 minute.

As shown in these Table 2, according to the sample of this embodiment, it turns out that all the dielectric constant (epsilon), tan (delta), and insulation resistance IR are stable also in high frequency ranges, such as a microwave.

On the other hand, in the sample of a comparative example, compared with the sample of this embodiment, it turns out that any of dielectric constant (epsilon), tan (delta), and insulation resistance IR fell.

Moreover, when the surface state of the sample of this embodiment was observed using the metal microscope, it was confirmed that it is a compact sintered compact, without recognizing a space | gap etc. in a grain boundary.

As described above, according to the ceramic capacitor of this embodiment, the dielectric (1) and containing TiO ₂ 20 ~ 80% by mole, the balance ZnO and incidental a week composition to impurities, CuO 0.5 ~ 20% by weight, MnO ₂ High relative dielectric constant, low tanδ, high, because the composition of the material is added 0.1 to 5% by weight, 0 to 5% by weight of Al ₂ O ₃ , 0.001 to 15% by weight of Sb ₂ O ₃ , and 0.5 to 10% by weight of the glass composition. Insulation resistance can be realized, and electrical characteristics can be stabilized in a high frequency region such as microwaves. Therefore, the reliability can be improved in the high frequency region.

According to the production process of the ceramic capacitor of this embodiment, containing 20 to 80% by mole of TiO _2, and a week composition with the balance ZnO and unavoidable impurities, CuO 0.5 ~ 20% by weight, MnO ₂ 0.1 ~ 5% by weight, Al ₂ O ₃ 0 - 5 wt.%, Sb of ₂ O ₃ 0.001 ~ 15% by weight, and the glass composition 0.5 to 10 mixed minutes to basis weight, mixing each of the powder such that the% add-in material composition by weight, and the mixture minutes The molded product is formed into a bulk molded product, and the molded product is calcined at a temperature of 800 ° C. or higher, whereby a high-strength sintered compact can be made by low temperature baking.

Second Embodiment

FIG. 2 is a diagram showing a multilayer ceramic capacitor according to a second embodiment of the present invention, wherein reference numeral 11 is a sheet-like dielectric layer, 12 is a thin internal electrode, 13 and 14 is a terminal electrode, and a dielectric layer 11 is shown. 8 layers and internal electrodes 12 are laminated | stacked alternately.

Dielectric layer 11 contains 20 to% 80 mol of TiO _2, and a week composition with the balance ZnO and unavoidable impurities, CuO 0.5 ~ 20 wt%, MnO ₂ 0.1 - 5 wt%, Al ₂ O ₃ 0 - 5 wt. %, Sb ₂ O ₃ 0.001 to 15% by weight, and 0.5-10% by weight of the glass composition.

The internal electrodes 12 and the terminal electrodes 13 and 14 are made of a highly reliable electrode material, for example, a metal mainly composed of Ag or Ag alloy, as a conductor. Examples of the Ag alloys include 90 Ag-10Pd.

This multilayer ceramic capacitor has stable characteristics even in the high frequency region.

Next, the manufacturing method of this multilayer ceramic capacitor is demonstrated.

First, the powdery TiO ₂ , ZnO, CuO, MnO ₂ , Al ₂ O ₃ , Sb ₂ O ₃ , and the glass composition are respectively weighed in a predetermined amount so as to obtain the material composition of the present embodiment, and these powders are filled in a predetermined amount of water ( Or it was put into a ball mill with a dispersion medium such as ethanol and acetone), and mixed and pulverized for a predetermined time, for example, for 24 hours, and then dehydrated (or an organic solvent such as deethanol and deacetone) was dried.

Next, after adding a predetermined amount of an organic binder and an organic solvent to this dried powder, it knead | mixed using a Leicaigi, a kneading machine, etc., and made it the slurry which has a predetermined viscosity. Here, PVA (polyvinyl alcohol) aqueous solution was used as an organic binder. In addition, as the organic binder, an aqueous solution of ethyl cellulose, an acrylic resin solution (acrylic binder), or the like may be preferably used in addition to the PVA aqueous solution.

Next, the slurry is formed into a sheet and degreased by a doctor blade method to form a green sheet, and a conductive paste containing Ag or Ag alloy such as 90Ag-10Pd as a main component on the green sheet in a predetermined pattern. The printed internal electrode layer was used.

Then, these green sheets were stacked in the thickness direction by the desired number of sheets, and then pressed in the thickness direction to form a laminate.

Next, this laminated body was baked at the temperature of 800 degreeC or more, and the terminal electrodes 13 and 14 were formed in the both sides after that.

As described above, a multilayer ceramic capacitor in which the dielectric layers 11 and the internal electrodes 12 were alternately stacked could be made.

As described above, according to the multilayer ceramic capacitor of the present embodiment, the dielectric layer 11 containing TiO ₂ 20 ~% 80 mol, per week composition with the balance ZnO and unavoidable impurities, CuO 0.5 ~ 20% by weight, MnO ₂ 0.1-5% by weight, 0-5% by weight of Al ₂ O ₃ , 0.001-15% by weight of Sb ₂ O ₃ , and 0.5-10% by weight of glass composition. Low dielectric loss, high insulation resistance can be realized, and electrical characteristics can be stabilized in a high frequency region such as microwave. Therefore, the reliability can be improved in the high frequency region.

According to the manufacturing method of the multilayer ceramic capacitor of the present embodiment, 0.5 to 20% by weight of CuO, 0.1 to 5% by weight of MnO ₂ , to a cast product containing 20 to 80 mol% of TiO ₂ and containing residual ZnO and unavoidable impurities, Using a mixture of Al ₂ O ₃ 0 to 5% by weight, Sb ₂ O ₃ 0.001 to 15% by weight, and a glass composition added 0.5 to 10% by weight, the green sheets were stacked in the thickness direction to form a laminate. Since the laminate is calcined at a temperature of 800 ° C. or higher, a metal such as Ag, which is cheaper than that of Pt or Pd, can be used as the material of the internal electrode 12, and precious metal such as Pt or Pd is used as an electrode material. No need to use Therefore, the cost reduction can be achieved without degrading a characteristic.

As mentioned above, although each embodiment of the dielectric magnetic composition of the present invention, the magnetic capacitor using the same, and the manufacturing method thereof has been described with reference to the drawings, the specific configuration is not limited to each of the above-described embodiments, and the scope of the present invention is avoided. It is possible to change the design within the range.

For example, in the multilayer ceramic capacitor according to the second embodiment, eight dielectric layers 11 and seven internal electrodes 12 are alternately stacked, but each of the dielectric layers 11 and 12 is formed. The size and the number of layers can be appropriately changed depending on the required capacity and characteristics.

As described above, according to the dielectric ceramic composition of the present invention, 0.5 to 20% by weight of CuO and 0.1 to 5% by weight of MnO _{2 are} contained in the main composition containing 20 to 80 mol% of TiO ₂ and the balance of ZnO and unavoidable impurities. , 0 to 5% by weight of Al ₂ O ₃ , 0.001 to 15% by weight of Sb ₂ O ₃ , and 0.5 to 10% by weight of glass composition can realize high dielectric constant, low dielectric loss, high insulation resistance, microwave, etc. The electrical characteristics can be stabilized in the high frequency region of. Therefore, the reliability can be improved in the high frequency region.

According to the magnetic capacitor of the present invention, since the electrodes are formed on both surfaces of the element made of the dielectric magnetic composition of the present invention, the dielectric loss can be reduced in the high frequency region. As a result, electrical characteristics can be stabilized in a high frequency region such as a microwave and reliability can be improved in a high frequency band.

In addition, since a metal such as Ag, which is relatively inexpensive compared to noble metals such as Pt and Pd, can be used as the electrode, the manufacturing cost can be reduced without deteriorating the characteristics.

According to the other magnetic capacitor of the present invention, since the sheet-like dielectric composed of the dielectric magnetic composition of the present invention and the laminate formed by alternately laminating the electrodes, the dielectric loss can be reduced in the high frequency region. As a result, electrical characteristics can be stabilized in a high frequency region such as microwaves, and reliability can be improved in the high frequency region.

In addition, since a metal such as Ag, which is relatively inexpensive compared to noble metals such as Pt and Pd, can be used as the electrode, the manufacturing cost can be reduced without deteriorating the characteristics.

According to the method for producing a dielectric ceramic composition of the present invention, 0.5 to 20% by weight of CuO, 0.1 to 5% by weight of MnO ₂ , and Al in a cast product containing 20 to 80 mol% of TiO ₂ and the balance of ZnO and unavoidable impurities ₂ O ₃ 0 ~ 5 _{wt%, Sb 2 O 3 0.001 ~} 15 % by weight, and the glass composition of 0.5 to 10% forming the added powder by weight, a bulk or a shaped body on the sheet, and the shaped article in at least 800 ℃ temperature Since it bakes, the sintered compact of high intensity | strength can be produced, being compact by low temperature baking.

According to another method for producing a dielectric ceramic composition of the present invention, an electrode is formed on one main surface of a sheet-shaped molded article, and then the molded articles are stacked and pressed in a plurality of thickness directions to form a laminate. Since it fires, metals, such as Ag, which are cheaper than noble metals, such as Pt and Pd, can be used as an internal electrode material, and it is not necessary to use precious metals, such as Pt and Pd, as an electrode material. Therefore, the cost reduction can be achieved without degrading the characteristic of a product.

Claims (6)

A TiO ₂ per week composition, the balance of ZnO and containing from 20 to% to 80 mol, CuO 0.5 - 20% by weight, MnO ₂ 0.1 - 5 wt%, Al ₂ O ₃ 0 - 5% by weight, Sb ₂ O ₃ 0.001 ~ A dielectric magnetic composition comprising 15% by weight and 0.5-10% by weight of the glass composition. The dielectric ceramic composition according to claim 1, wherein the glass composition is one of borosilicate glass, borosilicate glass, zinc borate glass, zinc borosilicate glass, and lead borate glass. The magnetic capacitor formed by forming electrodes on both surfaces of the element which consists of a dielectric composition of Claim 1 or 2. A magnetic capacitor comprising alternately stacking a sheet-like dielectric layer and an electrode layer made of the dielectric composition according to claim 1. 0.5 to 20 wt% of CuO, 0.1 to 5 wt% of MnO ₂ , 0 to 5 wt% of Al ₂ O ₃ , and Sb ₂ O _{3 to} 0.001 to 20 wt% of TiO ₂ and the cast product containing the balance ZnO. 10 wt% and 0.5-10 wt% of the glass composition are added to form a bulk or sheet-shaped molded product, and the molded product is fired at a temperature of 800 ° C. or higher. 6. The electrode according to claim 5, wherein an electrode is formed on one main surface of the sheet-shaped molded body, and then a plurality of the molded bodies are stacked and pressed in a thickness direction to form a laminated body, and the laminated body is fired at the above-mentioned temperature. Method for producing a dielectric magnetic composition.