TW201637035A - Ferrite composition and electronic component - Google Patents

Abstract

Provided is a ferrite composition composed of: a main component including 23.0 to 47.0 mole % of Fe compound in terms of Fe2O3, 3.0 to 16.0 mole % of Cu compound in terms of CuO, 4.0 to 39.0 mole % of Zn compound in terms of ZnO, 1.5 to 13.0 mole % of Si compound in terms of SiO2, and a residue of Ni compound; and a subcomponent including, with respect to 100 parts by weight of the main component, 0.1 to 8.0 parts by weight of Co compound in terms of Co3O4 and 0.25 to 5.00 parts by weight of Bi compound in terms of Bi2O3.

Description

Magnetic oxide composition and electronic component

The present invention relates to a magnetic oxide composition suitable for use in the manufacture of a laminated inductor or the like and an electronic component having the magnetic oxide composition.

Significant progress has been made in the high performance of portable devices such as smart phones. Recently, progress has been made to the use of near field communication (NFC), contactless power supply, etc., and circuits with high alternating current flow have increased as compared with the prior art.

In addition, due to the high density of electronic components, the demand for miniaturization of components is still strong. In general, when the AC current is increased, the size is reduced, and the like, the Q value of the inductance element is lowered. Due to such a situation, there is a demand for a magnetic core material having a high Q value and an inductance element using the magnetic core material even if an alternating current value is increased, miniaturization, or the like.

In particular, in a laminated inductor, it is required that the coil conductor and the magnetic oxide layer are integrally fired. Therefore, in the magnetic oxide composition for a laminated inductor, it is required to set the sintering temperature below the melting point of the coil conductor.

Patent Document 1 discloses a magnetic material in which SiO ₂ and CoO are added to a NiCuZn-based magnetic oxide to have stress resistance characteristics. However, the magnetic material of Patent Document 1 is a material sintered at 1050 ° C or higher. Furthermore, the Q value for the high amplitude current is not shown.

Patent Document 2 discloses a magnetic oxide material having excellent DC superposition characteristics using a NiCuZn-based magnetic oxide composed of a spinel magnetic oxide and zinc antimonate. However, the magnetic oxide material disclosed in Patent Document 2 does not show the Q value for the high amplitude current.

Patent Document 3 discloses a magnetic oxide material in which cobalt oxide is added to a NiCuZn-based magnetic oxide, and magnetic loss is small even at a high amplitude current. However, the temperature change rate of the inductance of the magnetic oxide material disclosed in Patent Document 3 is too large, and there are cases where the temperature characteristics of recent years cannot be satisfied.

The techniques of Patent Documents 1 to 3 have a certain effect on the characteristics of the respective techniques, but many of them are sacrificed for other purposes. In addition, the use is limited only when one characteristic is excellent. Therefore, a higher performance magnetic oxide composition is required.

[Patent Document 1] Japanese Patent Publication No. 02-137301

[Patent Document 2] Patent 5582279

[Patent Document 3] JP-A-2013-060332

In view of the above, an object of the present invention is to provide a low-temperature sintering, a small change in Q value for a change in an external magnetic field in a high external magnetic field (tens to hundreds of A/m), and a deterioration in Q value for a high amplitude current. A magnetic oxide composition having a small DC/DC superposition characteristic and excellent temperature characteristics, and an electronic component that can be miniaturized.

In order to achieve the above object, a magnetic oxide composition according to the present invention is characterized in that a main component is a compound of iron in an amount of 23.0 to 47.0 mol% in terms of Fe ₂ O ₃ , and 3.0 to 16.0 mol in terms of CuO. a compound having a percentage of copper, a compound having a zinc content of 4.0 to 39.0 mole percent in terms of ZnO, a compound having a cerium percentage of 1.5 to 13.0 mole percent in terms of SiO ₂ , and a balance of nickel compound; and relative to 100 weight The above-mentioned main component contains a compound of cobalt in an amount of 0.1 to 8.0 parts by weight in terms of Co ₃ O _{4 and} a compound of 0.25 to 5.00 parts by weight in terms of Bi ₂ O ₃ as a subcomponent.

In the magnetic oxide composition according to the present invention, the content of the oxide constituting the main component is in the above range, and further, cerium oxide and cobalt oxide as the subcomponents are contained in the above range, and low-temperature sintering is possible. For example, it is possible to sinter at a temperature of about 900 ° C (950 ° C or lower) which is lower than the melting point of silver which can be used as an internal electrode. Further, the magnetic oxide composition according to the present invention relating to the present invention, after sintering, has an external magnetic field raised to a high external magnetic field (tens to hundreds of A) compared to the previous external magnetic field (1 to 2 A/m). Under /m), the rate of decrease of the Q value is still small, and the deterioration of the Q value for the high amplitude current is still small. Further, the magnetic oxide composition according to the present invention is also excellent in temperature characteristics and DC superposition characteristics, and has a large electrical resistivity.

In the magnetic oxide sintered body comprising the magnetic oxide composition according to the present invention, since the characteristics are not deteriorated under a signal of a large amplitude as described above, it is possible to reduce the size of the electronic component.

Magnetic oxygen composed of the magnetic oxide composition related to the present invention In the sintered body of the chemical compound, since the direct current superposition characteristics are excellent as described above, it is possible to obtain a stable inductance value with little change in the magnetic permeability of the applied magnetic field. Thereby, even if the electronic component is miniaturized, the characteristics that can be obtained are not significantly different from those of the large electronic component using the prior magnetic oxide.

The magnetic oxide composition according to the present invention has good temperature characteristics as described above. Therefore, an electronic component using a magnetic core, a laminated inductor or the like of the magnetic oxide composition according to the present invention can be applied to a wide temperature environment.

Also, silver may be used as an internal electrode of an electronic member using the magnetic oxide composition of the present invention. Silver is cheaper than other metals and has a lower DC resistance.

The magnetic oxide composition according to the present invention preferably has a Zn ₂ SiO ₄ phase.

The electronic component according to the present invention is an electronic component having a sintered body of a magnetic oxide composed of the above-described magnetic oxide composition.

For example, an electronic component in which a coil conductor and a ceramic layer are laminated, the coil conductor contains silver, and the ceramic layer is composed of the above-described magnetic oxide composition.

In the electronic component according to the present invention, the characteristics of the electronic component having the large-amplitude signal are not deteriorated as compared with the electronic component having the magnetic oxide sintered body composed of the conventional magnetic oxide composition. Therefore, the size of the electronic component can be reduced.

The reason why such an effect can be obtained is considered to be a composite effect obtained by setting the main component to a predetermined range and further setting the content of each component to a specific range.

Further, the magnetic oxide composition of the present invention is composed of The magnetic oxide sintered body is suitable for a laminated inductor, an LC filter, a laminated common mode filter, a composite electronic component using another lamination method, and the like. For example, it is also applicable to LC composite electronic components, NFC coils, laminated impedance elements, and laminated transformers.

1‧‧‧Layered inductors

2‧‧‧ components

3‧‧‧Terminal electrode

4‧‧‧Magnetic oxide layer

5‧‧‧ coil conductor

5a, 5b‧‧‧ lead electrodes

10‧‧‧LC composite electronic components

12‧‧‧Inductor Department

14‧‧‧Capacitor Department

[Fig. 1] Fig. 1 is a cross-sectional view showing a laminated inductor according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing an LC composite electronic component according to an embodiment of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.

As shown in Fig. 1, a laminated inductor 1 according to an embodiment of the present invention includes an element 2 and a terminal electrode 3. The element 2 is a laminate in which the coil conductor 5 is formed into a three-dimensional and spiral-shaped green body through the magnetic oxide layer 4, and the laminate of the green embryo is obtained by firing. The magnetic oxide layer 4 is composed of a magnetic oxide composition according to an embodiment of the present invention. The terminal electrode 3 is formed at both ends of the element 2, and is connected to the terminal electrode 3 via the extraction electrodes 5a and 5b to obtain a laminated inductor 1. The shape of the element 2 is not particularly limited, but is usually a rectangular parallelepiped shape. Further, the size of the element 2 is not particularly limited, and an appropriate size may be set according to the use.

The material of the coil conductor 5 and the extraction electrodes 5a and 5b is not particularly limited, and silver, copper, gold, aluminum, palladium, palladium/silver alloy or the like can be used. Further, a titanium compound, a zirconium compound, a ruthenium compound or the like may be added.

The magnetic oxide composition according to the present embodiment contains iron oxide, copper oxide, zinc oxide, nickel oxide, and cerium oxide as main components.

In the percentage of 100 parts by mole of the main component, the content of iron oxide is 23.0 to 47.0 mol% in terms of Fe ₂ O ₃ , preferably 28.0 to 44.0 mol%, more preferably 33.0 to 37.0 mol%. When the content of iron oxide is too large or too small, the sinterability is deteriorated. In particular, the sintered density at the time of low-temperature sintering tends to decrease. In addition, the resistivity is remarkably lowered due to deterioration of sinterability.

In the percentage of 100% of the main component, the content of copper oxide is 3.0 to 16.0 mol% in terms of CuO, preferably 5.0 to 14.0 mol%, more preferably 5.5 to 14.0 mol%, and even more preferably 7.0 to 8.0 mol. Percentage of ears. When the content of the copper oxide is too small, the sinterability is deteriorated, and in particular, the sintered density at the time of low-temperature sintering tends to decrease. In addition, the resistivity is remarkably lowered due to deterioration of sinterability. If the content of the copper oxide is too large, the rate of decrease in the Q value for the DC superposition characteristic and the external magnetic field tends to deteriorate.

In the percentage of 100 parts by mole of the main component, the content of zinc oxide is 4.0 to 39.0 mole percent in terms of ZnO, preferably 5.0 to 39.0 mole percent, and more preferably 21.0 to 32.0 mole percent. If the content of zinc oxide is too low, the initial permeability μ _i tends to be too low. If the content of zinc oxide is too large, the rate of decrease in the Q value of the DC superposition characteristic and the external magnetic field tends to deteriorate. Also, the temperature of the courtesy has a tendency to decline.

In the percentage of 100 parts by mole of the main component, the content of cerium oxide is 1.5 to 13.0 mole percent in terms of SiO ₂ , preferably 3.0 to 11.0 mole percent, and more preferably 7.0 to 9.5 mole percent. When the content of cerium oxide is too small, the rate of decrease in the Q value of the DC superimposition characteristic and the external magnetic field tends to be deteriorated. If the content is too large, the rate of decrease in the Q value of the DC superimposition characteristic and the external magnetic field tends to deteriorate.

The balance of the main component is composed of nickel oxide.

The magnetic oxide composition according to the present embodiment contains cerium oxide and cobalt oxide as an auxiliary component in addition to the above main components.

The content of bismuth oxide with respect to 100 parts by weight of the main component in terms of Bi ₂ O ₃ is 0.25 to 5.00 parts by weight, preferably 0.50 to 3.00 parts by weight, more preferably 0.50 to 1.00 parts by weight. When the content of cerium oxide is too small, the sinterability is deteriorated, and in particular, the sintering density at the time of low-temperature sintering tends to decrease. In addition, the resistivity is remarkably lowered due to deterioration of sinterability. If the content of cerium oxide is too large, the electrical resistivity tends to decrease. Further, the rate of decrease in the Q value for the DC superimposition characteristic and the external magnetic field tends to deteriorate.

The content of the cobalt oxide is 0.1 to 8.0 parts by weight, preferably 0.1 to 3.0 parts by weight, more preferably 0.4 to 0.8 parts by weight, based on 100 parts by weight of the main component in terms of Co ₃ O ₄ . If the content of cobalt oxide is too small, the electrical resistivity tends to decrease. If the content of cobalt oxide is too large, the electrical resistivity tends to decrease. Further, there is a tendency that the temperature characteristics of the initial permeability are deteriorated.

Further, the content of each of the main components and the respective subcomponents hardly changes from the raw material powder stage to the subsequent steps after the firing of the dielectric body magnet composition.

In the magnetic oxide composition according to the present invention, the composition range of the main component is controlled outside the above range, and cerium oxide and cobalt oxide are contained as an auxiliary component in the above range. As a result, both high characteristics and low temperature sintering are considered. Specifically, the magnetic oxide composition of the present invention is due to an external magnetic field The decrease rate of the increased Q value is low, and the decrease in the Q value of the rise of the amplitude current is also small. Further, in the magnetic oxide composition according to the present invention, the DC superposition characteristics and the initial magnetic permeability are also excellent in temperature characteristics. Further, the magnetic oxide composition according to the present invention can be sintered at a temperature of 900 ° C or less below the melting point of silver used as the internal electrode. Therefore, it has become applicable to various uses. Further, in the magnetic oxide composition according to the present invention, since the characteristics are not deteriorated under a signal of a large amplitude, the size of the electronic component can be reduced.

In addition, the magnetic oxide composition according to the present embodiment may contain a manganese oxide such as Mn ₃ O ₄ , zirconia or tin oxide, in addition to the above-mentioned subcomponent, and may not contain the effect of the present invention. An additional component such as magnesium oxide or a glass compound. The content of these additional components is not particularly limited, and is, for example, about 0.05 to 1.0 part by weight.

In particular, the content of magnesium oxide is preferably 0.5 parts by weight or less. When the content of the magnesium oxide is 0.5 parts by weight or less, the reflection of MgO and SiO ₂ is suppressed, and the Zn ₂ SiO ₄ phase to be described later is easily formed.

Further, the magnetic oxide composition according to the present embodiment may contain an oxide of an unavoidable impurity element.

Specifically, examples of unavoidable impurities include C, S, Cl, As, Se, Br, Te, and I; Li, Na, Mg, Al, Ca, Ga, Ge, Sr, Cd, In, and Sb. Typical metal elements such as Ba, Pb, etc.; transition metal elements such as Sc, Ti, V, Cr, Y, Nb, Mo, Pd, Ag, Hf, Ta, and the like. Further, the oxide of the unavoidable element may be contained in an amount of 0.05 parts by weight or less in the magnetic oxide composition.

In particular, when the content of aluminum is 0.05 parts by weight or less in terms of Al ₂ O ₃ , the sinterability and the electrical resistivity are easily improved.

The average particle diameter of crystal grains in the magnetic oxide composition according to the present embodiment is preferably 0.2 to 1.5 μm.

Next, an example of a method for producing a magnetic oxide composition according to the present embodiment will be described. First, the starting materials (the raw materials of the main component and the raw materials of the subcomponents) are weighed and mixed for a predetermined composition ratio to obtain a raw material mixture. Examples of the method of mixing include wet mixing using a ball mill, dry mixing using a dry mixer, and the like. Further, it is preferred to use a starting material having an average particle diameter of 0.05 to 1.0 μm.

As a raw material of the main component, iron oxide (α-Fe ₂ O ₃ ), copper oxide (CuO), nickel oxide (NiO), zinc oxide (ZnO), cerium oxide (SiO ₂ ) or a composite oxide can be used. The composite oxide may, for example, be zinc ruthenate (Zn ₂ SiO ₄ ). In addition, various compounds which become the above-mentioned oxides, composite oxides, etc. by baking can be used. Examples of the substance which becomes the above-mentioned oxide by baking include a metal monomer, a carbonate, an oxalate, a nitrate, a hydroxide, a halide, an organometallic compound, and the like.

As a raw material of the subcomponent, cerium oxide and cobalt oxide can be used. The oxide of the raw material to be an accessory component is not particularly limited, and a composite oxide or the like can be used. In addition, various compounds which become the above-mentioned oxides, composite oxides, etc. by baking can be used. Examples of the substance which becomes the above-mentioned oxide by baking include a metal monomer, a carbonate, an oxalate, a nitrate, a hydroxide, a halide, an organometallic compound, and the like.

Further, Co ₃ O ₄ in one form of cobalt oxide is easy to store, handle, etc., and even if the valence is stable in air, it is preferable to use it as a raw material of cobalt oxide.

Next, calcination of the raw material mixture is carried out to obtain a calcined material. Calcination is caused by thermal decomposition of raw materials, homogenization of components, formation of magnetic oxides, disappearance of ultrafine powders due to sintering, and grain growth to a moderate grain size, for the purpose of converting the raw material mixture into a suitable step. . The calcination time and the calcination temperature are not particularly limited. The calcination is usually carried out in the atmosphere (air), but it can also be carried out in an atmosphere in which the partial pressure of oxygen is lower than that in the atmosphere.

Next, pulverization of the calcined material is carried out to obtain a pulverized material. The pulverization is carried out in order to break the aggregation of the calcined material and to form a powder having moderate sinterability. When the calcined material is formed into a large block, it is coarsely pulverized, and then wet pulverized using a ball mill, an attritor or the like. The wet pulverization is carried out until the average particle diameter of the pulverized material is preferably about 0.1 to 1.0 μm.

Further, in the above method for producing a pulverized material, the powder of the main component and the powder of the subcomponent are all mixed and calcined. However, the method of producing the pulverized material is not limited to the above method.

A part of the raw material powder which has been mixed before the calcination may be mixed while pulverizing the calcined material after calcination, instead of being mixed with other raw material powders before calcination.

Preferably, cerium oxide, cerium oxide and cobalt oxide are mixed while pulverizing the calcined raw material. It is preferable to mix cerium oxide at the time of pulverizing the calcined raw material so that a part or all of the zinc oxide is mixed with cerium oxide. This is because the Zn ₂ SiO ₄ phase described later is easily formed during the sintering process.

Further, when zinc oxide is mixed with cerium oxide at the time of pulverizing the calcined raw material, the amount of zinc oxide mixed at the time of pulverizing the calcined raw material is mixed at the time of pulverizing the calcined raw material on a mass basis. The amount of cerium oxide is preferably 1.0 to 3.0 times. This is because the Zn ₂ SiO ₄ phase described later is easily formed during the sintering process.

A laminated inductor according to the present embodiment was produced using the obtained pulverized material. The method for manufacturing the laminated inductor is not particularly limited, and the following is a method of forming a sheet.

First, the obtained pulverized material is slurried together with an additive such as a solvent or a binder to prepare a pulverized product. This paste is then used to form a green sheet. Next, the formed green sheets are processed into a predetermined shape, and the laminated inductors according to the present embodiment are obtained through a debonding step and a firing step. The firing is performed at a temperature equal to or lower than the melting point of the coil conductor 5 and the extraction electrodes 5a and 5b. For example, when the coil conductor 5 and the extraction electrodes 5a and 5b are silver (melting point 962 ° C), it is preferably carried out at a temperature of 850 to 920 °C. The firing time is usually about 1 to 5 hours. Further, the firing may be carried out in the atmosphere (air), but may be carried out in an atmosphere having a partial pressure of oxygen lower than that in the atmosphere. The laminated inductor obtained in this manner is composed of the magnetic oxide composition according to the present embodiment.

The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit and scope of the invention. For example, the magnetic oxide composition of the present invention can also be used as the magnetic oxide layer 4 in the LC composite electronic component 10 shown in Fig. 2 . In addition, in the second drawing, the portion indicated by the reference numeral 12 is an inductor portion, and the portion indicated by the reference numeral 14 is a capacitor portion.

When the magnetic oxide composition according to the present invention is subjected to X-ray diffraction, elemental analysis by EPMA or STEM, or the like, the presence of the magnetic oxide phase can be confirmed. In a preferred embodiment of the magnetic oxide composition of the present invention, there is a Zn ₂ SiO ₄ phase different from the above magnetic oxide phase. The presence of the above Zn ₂ SiO ₄ phase can be confirmed by X-ray diffraction, elemental analysis by EPMA or STEM, and the like. In the case of confirmation by any method, it is preferable to observe at a magnification of 5,000 to 50,000 times in the observation field.

Further, the content of the Zn ₂ SiO ₄ phase can be confirmed by an X-ray diffraction device. Hereinafter, the definition and measurement method of the content of the Zn ₂ SiO ₄ phase in the present application will be described.

The X-ray diffraction intensity of the magnetic oxide composition was measured by an X-ray diffraction device, and the peak intensity I _A and Zn ₂ SiO ₄ of the (311) plane of the spinel-type magnetic oxide phase in the magnetic oxide composition were measured. The peak intensity of the (113) plane is I _B . The content of the Zn ₂ SiO ₄ phase in the present application is the above I _B divided by the value of I _A (I _B /I _A ). Further, the X-ray diffraction intensity is obtained by subtracting the background value from the intensity indicated by the X-ray diffraction device.

Content of Zn ₂ SiO ₄ phase, peak intensity is the peak intensity (311) plane of the Zn ₂ SiO ₄ peak intensity of the (113) plane is I _B in contrast to magnetic spinel oxide phase ratio I _B I _A It is preferable that /I _A is 0.006 or more. Further, the upper limit of the content of the Zn ₂ SiO ₄ phase is not particularly limited, and the above I _B /I _A is preferably 0.190 or less.

It is recognized that the elastic modulus and thermal expansion coefficient of the Zn ₂ SiO ₄ phase are smaller than those of the magnetic oxide phase. It is recognized that the Zn ₂ SiO ₄ phase imparts a better inductive property to the stress based on the difference in thermal expansion coefficient below the magnetic oxide phase. The inventors inferred case, by the above reasons, Zn ₂ SiO ₄ formed with Zn ₂ SiO ₄ phase characteristics of magnetic oxide composition is not formed than Zn ₂ SiO ₄ phase composition having excellent magnetic oxide.

Further, the Zn ₂ SiO ₄ phase may be present in the sintered magnetic oxide composition, and may not necessarily be present in the magnetic oxide composition before sintering. Further, when the pulverization of the calcined material so that a portion of the silicon oxide and zinc oxide mixed together, the addition of silicon or zinc (Zn ₂ SiO ₄₎ during pulverization of the calcined material, Zn ₂ SiO ₄ easily formed phase. In the case where a part of zinc oxide is mixed with cerium oxide at the time of pulverizing the calcined material, zinc oxide (ZnO) and cerium oxide (SiO ₂ ) are combined to form a Zn ₂ SiO ₄ phase during the sintering process. However, the method of forming the Zn ₂ SiO ₄ phase is not limited to the above method.

Further, bismuth oxide (Bi ₂ O ₃ ) has an effect of lowering the sintering temperature. It also has the effect of promoting the formation of the Zn ₂ SiO ₄ phase during the sintering process. And in the case of bismuth oxide added during pulverization of the calcined material, in particular by promoting generation Zn ₂ SiO ₄ phase effect increases, and it becomes possible to generate be Zn ₂ SiO ₄ phase stably.

Further, cobalt oxide (Co ₃ O ₄ ) increases the resistivity and suppresses a decrease in the Q value of the high-amplitude current, but tends to deteriorate the temperature characteristics of the initial permeability. However, by the presence of the Zn ₂ SiO ₄ phase, there is an effect of suppressing the deterioration of the temperature characteristics of the initial permeability. At the same time, there is an effect of maximizing the effect of suppressing the decrease in the Q value of the high amplitude current.

[Examples]

Hereinafter, the present invention will be further described based on the detailed examples, but the present invention is not limited to the examples.

First, Fe ₂ O ₃ , NiO, CuO, ZnO, and SiO _{2 are} prepared as raw materials for the main component. Raw materials of Bi ₂ O ₃ and Co ₃ O ₄ as auxiliary components were prepared. Further, the average particle diameter of the starting material is preferably from 0.05 to 1.00 μm.

Next, the composition described in Table 1 is used as a sintered body. For the purpose, the powder of the main component raw material prepared and the powder of the auxiliary component raw material are weighed.

After weighing, among the prepared main component materials, Fe ₂ O ₃ , NiO, CuO, and a part of ZnO, which are prepared as a main component, are wet-mixed in a ball mill for 16 hours to obtain a raw material mixture. .

Next, the obtained raw material mixture was dried, and then calcined in the air to obtain a calcined product. The calcination temperature is appropriately selected in the range of 500 to 900 ° C in accordance with the composition of the raw material mixture. Thereafter, the raw material of the above-mentioned subcomponent, SiO ₂ and the remaining portion of ZnO which were not mixed in the wet mixing step were pulverized in a ball mill to obtain pulverized powder.

The amount of the remaining portion of the ZnO added to the calcined product is 1.0 to 3.0 times the amount of SiO ₂ added in terms of moles.

Next, after the pulverized powder was dried, 10.0 parts by weight of a 6 wt% aqueous polyvinyl alcohol solution as a binder was added to 100 parts by weight of the pulverized powder, and granulated to obtain granules. The pellet was press-formed to obtain a molded body of a ring A (size = outer diameter 13 mm × inner diameter 6 mm × height 3 mm), and a molded body of a ring B (size = outer diameter 8 mm × inner diameter 4 mm × height 2.5 mm) and a disk A molded body of a shape (size = outer diameter 12 mm × height 2 mm).

Next, these formed bodies were fired at 860 to 900 ° C in the air at a melting point (962 ° C) or less of silver for 2 hours to obtain a ring-shaped sample A, a ring-shaped sample B, and a disk-shaped sample as a sintered body. Further, the following characteristics were evaluated for each of the obtained samples. In addition, it was confirmed by the fluorescent X-ray analyzer that the composition of the raw material powder to be weighed and the molded body after firing hardly changed.

Resistivity ρ

An In-Ga electrode was applied to both surfaces of the disk sample, and the DC resistance value was measured to obtain a specific resistance (unit: Ω‧ m). The measurement was performed using an infrared meter (4329A manufactured by HEWLETT PACKARD Co., Ltd.). In the present embodiment, the specific resistance ρ is 10 ⁶ Ω ‧ m or more. In the case of a sample having a specific resistance ρ of less than 10 ⁵ Ω ‧ m, it is judged that it is not worthwhile to perform other characteristic evaluation, and the following characteristic evaluation is omitted.

Initial permeability μ _i

The copper wire was wound 10 times in the ring sample A, and the initial permeability μ _{i was} measured using an LCR meter (4991A manufactured by Agilent Technologies, Inc.). The measurement conditions were as follows: measurement frequency 1 MHz, measurement temperature 25 °C.

DC overlap characteristic

The copper wire was wound 10 turns in the ring sample A, and the magnetic permeability μ when a direct current was applied was measured. The magnetic permeability μ was measured while changing the applied current from 0 to 8 A, and the direct current was taken as the horizontal axis and the magnetic permeability was taken as the vertical axis, and the graph was graphed. The magnetic permeability at a direct current of 0 A is the initial permeability μ _i . Then, the current value Idc30%down when the magnetic permeability decreased by 30% from μ _i was obtained.

When the applied current is 8 A or less, the magnetic permeability is decreased by 30%, and when the magnetic permeability is decreased by 30%, the direct current is Idc 30% down. In the case where the magnetic permeability has not decreased by 30% at the time point when the applied direct current is 8 A, Idc 30%down is calculated from the degree of inclination of the curve of the direct current 8A. When the applied DC current is between 0 and 8 A, the magnetic permeability μ does not change, and Idc 30%down is set to be unsaturated.

In this embodiment, Idc 30%down is unsaturated or 10.0A. In the above case, it is assumed that the DC superimposition characteristic is good.

Q rate of decline

In the ring sample B, the copper wire was wound 6 times on the primary side and the copper wire was wound 3 times on the secondary side, using a BH analyzer (SY-8218 manufactured by Rockwell Meter) and an amplifier (NF circuit design) 4101-IW manufactured by the company, the Q value in the case of applying an external magnetic field of 100 A/m and the Q value in the case of applying 500 A/m. The measurement conditions other than the external magnetic field were measured at a measurement frequency of 3 MHz and a measurement temperature of 25 °C. From the measured Q value, the rate of decrease in the Q value when the external magnetic field was increased from 100 A/m to 500 A/m was calculated.

In the present embodiment, the case where the rate of decrease of Q in the case where the external magnetic field is increased from 100 A/m to 500 A/m is 45.0% or less is considered to be good. Further, when the rate of decrease of Q is small, the deterioration of the Q value of the high amplitude current is also small.

Temperature characteristics of initial permeability μ _i

Using a room temperature of 25 ° C as a standard, the rate of change of the initial permeability μ _i at 25 ° C to 125 ° C was determined. In the present embodiment, the case where the rate of change of μ _i is within ±30% is considered to be good.

The presence and content of Zn ₂ SiO ₄ phase

With respect to the above-described sintered magnetic oxide composition, the presence or absence of the Zn ₂ SiO ₄ phase was examined by STEM. The magnification of the observed field of view is 20,000 times. Further, the content of the Zn ₂ SiO ₄ phase was examined by an X-ray diffraction apparatus (X'Pert PRO MPD CuKα line manufactured by Panalytical Co., Ltd.).

The above test results are summarized in Table 1.

From Table 1, it was confirmed that the content of the main component and the subcomponent was within the range of the present invention, and all of the properties were good.

When the composition of the main component is within the range of the present invention and Co ₃ O ₄ is not contained (sample Nos. ₄ , 11, and 47), the specific resistance ρ is less than 10 ⁶ . When the amount of addition of Co ₃ O ₄ exceeds 8.0 parts by weight (sample Nos. 5a and 5d), the temperature characteristics of the initial permeability or the specific resistance ρ deteriorate.

When the composition of the main component is within the range of the present invention and Bi ₂ O ₃ is not contained (sample Nos. 21, 25, 47), the specific resistance ρ is remarkably lowered to be less than 10 ⁵ . When the amount of Bi ₂ O ₃ added exceeds 5.00 parts by weight (sample No. 13), the specific resistance ρ is less than 10 ⁶ , and the DC superposition characteristics and the rate of decrease of Q are deteriorated.

In the case where the content of Fe ₂ O ₃ was less than 23.0 mol% (sample No. 27), the electrical resistivity decreased remarkably to be less than 10 ⁵ .

When the content of ZnO exceeds 43.0 mol% (sample No. 48), the DC superposition characteristics and the rate of decrease of Q deteriorate. Further, since the Curie temperature was lowered to 100 ° C or lower, the temperature characteristics of the initial permeability could not be measured.

In the case where the content of CuO is less than 3.0 mol% (sample No. 49), the electrical resistivity is remarkably lowered to be less than 10 ⁵ .

In the case where the content of SiO ₂ was less than 1.5 mol% (sample Nos. 12, 40, and 44), the DC superposition characteristics were deteriorated. At sample numbers 12 and 44, the rate of decrease of Q also deteriorated. When the content of SiO ₂ exceeds 13.0 mol% (sample No. 48), the DC superposition characteristics and the rate of decrease of Q deteriorate.

In the sintered magnetic oxide composition in all the examples, it was confirmed that the Zn ₂ SiO ₄ phase was present. Further, it was confirmed that the content (I _B /I _A ) of the above Zn ₂ SiO ₄ phase was 0.006 or more.

Then, in addition to the powder of the main component raw material prepared and the powder of the subcomponent raw material prepared for the purpose of the composition described in Tables 2 to 8 as the sintered body, the same as the examples described in Table 1 were carried out. . Further, a predetermined amount of magnesium oxide or aluminum oxide was added to sample No. 121 and sample No. 122 of Table 8, respectively.

From Tables 2 to 7, it can be confirmed that even if the content of each component is Within the predetermined range, when the contents of the main component and the subcomponent are all within the range of the present invention, all the characteristics are good. From Table 8, it was confirmed that even when magnesium oxide and aluminum oxide were added, when the contents of the main component and the subcomponent were all within the range of the present invention, all the characteristics were good.

1‧‧‧Layered inductors

2‧‧‧ components

3‧‧‧Terminal electrode

4‧‧‧Magnetic oxide layer

5‧‧‧ coil conductor

5a, 5b‧‧‧ lead electrodes

Claims (3)

A magnetic oxide composition characterized by having a main component of a compound having an iron content of 23.0 to 47.0 mol% in terms of Fe ₂ O ₃ , a compound having a copper content of 3.0 to 16.0 mol% in terms of CuO, and ZnO a compound having a zinc content of 4.0 to 39.0 mol%, a compound having a cerium percentage of 1.5 to 13.0 mol% in terms of SiO ₂ , and a balance of nickel compound; and containing 100 parts by weight of the above main component A compound in which Co ₃ O _{4 is} converted into a cobalt of 0.1 to 8.0 parts by weight, and a compound having a ruthenium of 0.25 to 5.00 parts by weight in terms of Bi ₂ O ₃ is used as an accessory component. The magnetic oxide composition according to claim 1, which contains a Zn ₂ SiO ₄ phase. An electronic component comprising a magnetic oxide sintered body comprising the magnetic oxide composition according to claim 1 or 2.