阅读说明：本技术 复合磁性材料和使用该复合磁性材料的电子部件 (Composite magnetic material and electronic component using the same ) 是由 杉井一星 加藤贤一 于 2019-05-30 设计创作，主要内容包括：本发明提供一种复合磁性材料和使用该复合磁性材料的电子部件,该复合磁性材料可实现元件体的电阻率高的电子部件。该复合磁性材料含有铁氧体组合物和硅酸锌,其中,铁氧体组合物由尖晶石系铁氧体和存在于尖晶石系铁氧体中的氧化铋构成,相对于复合磁性材料整体的重量的氧化铋的重量的比例为0.025重量％～0.231重量％,相对于硅酸锌的重量和尖晶石系铁氧体的重量的合计的硅酸锌的重量的比例为8重量％～76重量％。(the invention provides a composite magnetic material and an electronic component using the same, wherein the composite magnetic material can realize an electronic component with a high electrical resistivity of an element body. The composite magnetic material comprises a ferrite composition and zinc silicate, wherein the ferrite composition comprises a spinel ferrite and bismuth oxide present in the spinel ferrite, the proportion by weight of the bismuth oxide relative to the weight of the entire composite magnetic material is 0.025 to 0.231% by weight, and the proportion by weight of the zinc silicate relative to the total weight of the zinc silicate and the weight of the spinel ferrite is 8 to 76% by weight.)

1. A composite magnetic material comprises a ferrite composition and zinc silicate,

The ferrite composition is composed of a spinel ferrite and bismuth oxide present in the spinel ferrite, and the proportion of the bismuth oxide by weight relative to the weight of the entire composite magnetic material is 0.025 to 0.231% by weight,

The ratio of the weight of the zinc silicate to the total weight of the zinc silicate and the weight of the spinel ferrite is 8 to 76 wt%.

2. The composite magnetic material according to claim 1, wherein the proportion of the weight of the zinc silicate to the total of the weight of the zinc silicate and the weight of the spinel ferrite is 8 to 25 wt%.

3. An electronic component includes: a device body formed by laminating a plurality of magnetic layers, an external electrode provided on an outer surface of the device body, a coil conductor provided inside the device body, and a lead conductor electrically connecting the external electrode and the coil conductor,

Wherein the element body is composed of the composite magnetic material according to claim 1 or 2.

Technical Field

The present invention relates to a composite magnetic material and an electronic component using the same.

background

As a material for an element body of a laminated coil component for removing high-frequency noise of an electronic device, a composite magnetic material containing a magnetic material and a non-magnetic material has been used.

Patent document 1 describes a composite ferrite composition containing a magnetic material and a nonmagnetic material, wherein the magnetic material is a Ni — Cu — Zn ferrite, the nonmagnetic material contains a low dielectric constant nonmagnetic material represented by a general formula a (bZnO — cuo) · SiO ₂, in which a, b, and c satisfy a condition of a being 1.5 to 2.4, b being 0.85 to 0.98, and c being 0.02 to 0.15 (where b + c is 1.00), and bismuth oxide, and the mixing ratio of the magnetic material and the low dielectric constant nonmagnetic material is 80 wt%: 20 wt%: 10 wt%: 90 wt%.

Disclosure of Invention

According to the studies of the present inventors, it has been found that when a composite magnetic material contains a large amount of bismuth oxide as a sintered material, in an electronic component produced using the composite magnetic material, defects such as a decrease in the resistivity of the element body and an elongation of the plating layer tend to occur, and there is a problem that the reliability of the electronic component is lowered.

The invention provides a composite magnetic material capable of realizing an electronic component with a high element resistivity, and an electronic component using the composite magnetic material.

The present inventors have found that a composite magnetic material capable of realizing an electronic component having a high element resistivity can be obtained by controlling the bismuth oxide content to a predetermined range in a composite magnetic material obtained by using a ferrite composition containing bismuth oxide as a magnetic material and zinc silicate as a nonmagnetic material, and have completed the present invention.

According to the 1 st aspect of the present invention, there is provided a composite magnetic material comprising a ferrite composition and zinc silicate,

The ferrite composition comprises a spinel ferrite and bismuth oxide present in the spinel ferrite, wherein the proportion of bismuth oxide by weight relative to the weight of the entire composite magnetic material is 0.025 to 0.231% by weight,

the ratio of the weight of zinc silicate to the total weight of the weight of zinc silicate and the weight of spinel ferrite is 8 to 76 wt%.

According to the 2 nd gist of the present invention, there is provided an electronic component including: a component body formed by laminating a plurality of magnetic layers, an external electrode provided on an outer surface of the component body, a coil conductor provided inside the component body, and a lead conductor electrically connecting the external electrode and the coil conductor,

Wherein the element body is made of the composite magnetic material.

The composite magnetic material of the present invention has the above-described features, and thus can realize an electronic component having a high element resistivity.

Drawings

Fig. 1 is an internal perspective view of an electronic component according to an embodiment of the present invention.

Fig. 2 is an internal perspective view of an electronic component of another embodiment of the present invention.

Description of the symbols

1 electronic component

2 element body

3 coil conductor

4 lead-out conductor

5 external electrode

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are for illustrative purposes, and the present invention is not limited to the embodiments described below.

(composite magnetic Material)

The composite magnetic material of the present embodiment is a composite material containing a ferrite composition and zinc silicate (willemite). The zinc silicate can be represented by a (bZn. cMO) SiO ₂, wherein a is in the range of 1.5 to 2.4, b is in the range of 0.85 to 1, and c is in the range of 0.00 to 0.15.

The ferrite composition is composed of a spinel-based ferrite and bismuth oxide (Bi ₂ O ₃) present in the spinel-based ferrite, and as the spinel-based ferrite, for example, Ni-Cu-Zn-based ferrite, Mn-Cu-Zn-based ferrite, Ni-Mn-Cu-Zn-based ferrite, and the like can be used, and a composite magnetic material excellent in high-frequency characteristics can be obtained by using the above spinel-mentioned spinel-based ferrite, the composition of the spinel-based ferrite is not particularly limited, and can be appropriately selected according to the purpose, the spinel-based ferrite can contain one or more selected from Co, Mn, and Sn, for example, the Ni-Cu-Zn-based ferrite can contain Co in the range of 1ppm to 200ppm, Mn in the range of 1ppm to 3000ppm, Sn. in the range of 1ppm to 1000ppm, and the Mn-Cu-Zn-based ferrite and the Ni-Mn-Cu-Zn-based ferrite can contain Co in the range of 1ppm to 200ppm and Sn in the range of 1ppm to 1000ppm, respectively.

Bismuth oxide functions as a sintering material for improving the sinterability of the composite magnetic material. In the composite magnetic material of the present embodiment, bismuth oxide is present inside the spinel ferrite. The bismuth oxide present in the interior of the ferrite is bismuth oxide present at grain boundaries of ferrite grains. By making bismuth oxide exist inside the spinel ferrite, the amount of bismuth oxide added can be reduced, and the sinterability of the composite magnetic material can be improved. The composite magnetic material may contain a small amount of bismuth oxide present on the surface and outside of the spinel ferrite in addition to the bismuth oxide present inside the spinel ferrite. In this case, the proportion of the weight of bismuth oxide present in the spinel ferrite to the weight of the entire bismuth oxide contained in the composite magnetic material is preferably greater than 50 wt%.

The proportion by weight of bismuth oxide relative to the weight of the entire composite magnetic material is 0.025 to 0.231 wt%, preferably 0.036 to 0.21 wt%. When the weight ratio of bismuth oxide is 0.025 wt% or more, preferably 0.036 wt% or more, the sinterability of the composite magnetic material can be improved, and the water absorption of the composite magnetic material can be reduced. If the weight ratio of bismuth oxide is 0.231 wt% or less, preferably 0.21 wt% or less, a high resistivity of 9log Ω · cm or more can be ensured.

The content of bismuth oxide contained in the composite magnetic material can be represented by the ratio of the weight of bismuth oxide to the weight of spinel-based ferrite. In this case, the proportion of the weight of bismuth oxide relative to the weight of the ferrite composition is 0.1 to 0.25 wt%, preferably 0.15 to 0.25 wt%. When the weight ratio of bismuth oxide is within the above range, the sinterability of the composite magnetic material can be improved, and a high resistivity of 9log Ω · cm or more can be secured.

When the composition ratio of zinc silicate and spinel ferrite is expressed by weight ratio, the ratio of the weight of zinc silicate to the total weight of the weight of zinc silicate and the weight of spinel ferrite is 8 to 76% by weight. If the weight ratio of zinc silicate as the nonmagnetic material is too large, the magnetic permeability of the composite magnetic material becomes low and the water absorption of the composite magnetic material becomes high. On the other hand, if the weight ratio of zinc silicate is too small, the direct current superposition characteristic becomes low. When the weight ratio of the zinc silicate to the spinel ferrite is within the above range, the composite magnetic material can achieve both high magnetic permeability and good direct current superposition characteristics, and can reduce the water absorption rate.

The composition ratio of the zinc silicate and the spinel-based ferrite can also be expressed by a volume ratio. In this case, the ratio of the volume of the zinc silicate to the total volume of the zinc silicate and the volume of the spinel ferrite is 10 to 80 vol%. When the volume ratio of the zinc silicate to the spinel ferrite is within the above range, high magnetic permeability and good direct current superposition characteristics can be achieved, and the water absorption of the composite magnetic material can be reduced.

When the composition ratio of the zinc silicate and the spinel ferrite is expressed by a weight ratio, the ratio of the weight of the zinc silicate to the total weight of the zinc silicate and the weight of the spinel ferrite is preferably 8 to 25% by weight. When the composition ratio of the zinc silicate and the spinel-based ferrite is expressed by a volume ratio, the ratio of the volume of the zinc silicate to the total volume of the zinc silicate and the volume of the spinel-based ferrite is preferably 10 to 30 vol%. When the composition ratio of the zinc silicate and the spinel ferrite is within the above range, a higher permeability of 10H/m or more can be secured.

The composite magnetic material preferably does not contain borosilicate glass. At this time, the composite magnetic material may be composed of only the ferrite composition and the zinc silicate. However, the composite magnetic material may further contain a small amount of unavoidable impurities such as impurities contained in the raw materials and impurities derived from a dispersant, a binder, a plasticizer, and the like used in the production. As described later, in the case of manufacturing an electronic component including an element body made of the composite magnetic material according to the present embodiment, the layered molded body may be barrel-polished in water before the layered molded body is fired to obtain the element body. When the composite magnetic material contains borosilicate glass, there is a possibility that the glass component is eluted from the laminated molded body during barrel polishing in the water, and therefore, there is a possibility that the sinterability of the element body varies. When the composite magnetic material does not contain borosilicate glass, since the glass component is not eluted during barrel polishing in water, the sintering property of the element body can be prevented from being deteriorated.

further, when the composite magnetic material does not contain borosilicate glass, the strength (bending strength) of the element body made of the composite magnetic material can be improved. As a result, cracks are less likely to occur when the electronic component is mounted, and the reliability of the electronic component can be improved.

The reason why the strength of the element body is improved when the composite magnetic material does not contain borosilicate glass is not bound by a particular theory, but is presumed to be due to the following mechanism: when the composite magnetic material contains a glass component, glass exists in the grain boundary. If glass exists in the grain boundaries, cracks are likely to occur along the grain boundaries (i.e., the grain boundaries are likely to crack), and as a result, the strength of the element body is reduced. On the other hand, when the composite magnetic material does not contain a glass component, since there is no glass as a grain boundary component, the strength is not lowered by the presence of the glass. In addition, when the composite magnetic material does not contain a glass component, grain growth is not easily performed during firing, and therefore the amount of large particles present in the obtained element body is reduced, and the element body becomes an aggregate of fine particles. Therefore, the number of necks of the particles increases, and the strength of the element body is improved. Further, since the amount of large particles present is small, even if cracks are generated, the distance over which the cracks extend linearly tends to be difficult to lengthen, and as a result, the strength is improved.

Next, a method for manufacturing the composite magnetic material of the present embodiment will be described. However, the method described below is merely an example, and the method for manufacturing the composite magnetic material according to the present embodiment is not limited to the method described below.

The spinel ferrite powder and bismuth oxide are weighed and mixed so that the ratio of the weight of bismuth oxide to the total weight of the spinel ferrite powder and the bismuth oxide is 0.1 to 0.25 wt%, and the resulting mixture is presintered at a temperature of 600 to 800 ℃ to obtain a ferrite composition powder. The ferrite composition powder and the zinc silicate powder are weighed so that the ratio of the weight of the zinc silicate to the total weight of the zinc silicate and the weight of the spinel ferrite is 8 to 76 wt%. Pure water, a dispersant, a binder and/or a plasticizer are added thereto, and dispersion and pulverization are performed by a ball mill or the like to obtain a slurry. The slurry is molded by a doctor blade method or the like, and the obtained molded body is calcined at a temperature of 880 to 930 ℃. It is considered that the composition ratio of the spinel-based ferrite powder, the bismuth oxide powder and the zinc silicate powder used as the raw materials of the composite magnetic material is substantially the same as the composition ratio in the obtained composite magnetic material.

(electronic parts)

Next, an electronic component according to an embodiment of the present invention will be described. Fig. 1 shows an example of an electronic component according to the present embodiment. The electronic component 1 shown in fig. 1 is a laminated coil component. The electronic component 1 of the present embodiment includes: the element body 2 is formed by laminating a plurality of magnetic layers, an external electrode 5 provided on an outer surface of the element body 2, a coil conductor 3 provided inside the element body 2, and a lead conductor 4 electrically connecting the external electrode 5 and the coil conductor 3, and the element body 2 is formed of the composite magnetic material of the present invention. The electronic component of the present embodiment may have a so-called longitudinal winding structure as shown in fig. 1 or a so-called transverse winding structure as shown in fig. 2. The electronic component of the present embodiment has a high resistivity of the element body.

The laminated coil component as the electronic component of the present embodiment can be manufactured, for example, by the method described below. First, spinel ferrite powder and bismuth oxide are weighed and mixed so that the ratio of the weight of bismuth oxide to the total weight of the spinel ferrite powder and the bismuth oxide is 0.1 to 0.25% by weight, and the resulting mixture is presintered at a temperature of 600 to 800 ℃ to obtain ferrite composition powder. The ferrite composition powder and the zinc silicate powder are weighed so that the ratio of the weight of the zinc silicate to the total weight of the zinc silicate and the weight of the spinel ferrite is 8 to 76 wt%. Pure water, a dispersant, a binder and/or a plasticizer and the like are added thereto, and dispersion and pulverization are performed with a ball mill or the like to obtain a slurry. The slurry is formed into a sheet having a predetermined thickness by doctor blade method or the like. The obtained sheet was irradiated with laser light at a predetermined position to form a via hole, and the via hole was filled with a conductive paste. Next, a conductive paste is screen-printed on the sheet, thereby forming a coil conductor pattern and a lead-out conductor pattern.

The sheet having the conductor pattern formed thereon is laminated in a predetermined order, and after further laminating sheets having no conductor pattern formed thereon and thereafter, the laminated sheets are heated and pressed, and cut by a dicing saw or the like to be singulated, thereby producing a laminated molded body. By barrel-polishing the laminated molded body in water, the corner of the laminated molded body can be rounded. The laminated molded body is fired at a temperature of 880 to 930 ℃ to obtain an element body having a coil conductor provided therein. An external electrode is formed by applying a conductive paste for external electrodes to the outer surface of the element body and baking the element body at a temperature of about 900 ℃. Plating treatment may be performed on the external electrode. This makes it possible to obtain the electronic component of the present embodiment.

The electronic component according to the present embodiment may be an electronic component other than the laminated coil component shown in fig. 1 or 2, or may be a composite electronic component in which a coil and another element such as a capacitor are combined, for example, an LC composite component.