JP7240011B2 - ELECTRODE-FORMING MATERIAL, ELECTRODE MANUFACTURING METHOD, AND ELECTRODE - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrode-forming material, an electrode manufacturing method, and an electrode.

2. Description of the Related Art Conventionally, as methods for forming electrodes of electronic components, a baking method using a conductive paste (thick film method), an electroplating method, a thin film method using physical vapor deposition, and the like are known. Among these methods, the baking method is widely used because it is a simple method and provides a thick electrode with excellent conductivity. In the baking method, a conductive paste containing conductive metal powder such as silver powder is applied onto a substrate, dried, and then sintered to form an electrode.

In the baking method, a method using a printing screen, a method of etching an electrode, or a method using a photosensitive conductive paste is used to obtain a patterned electrode (patterned electrode) such as a fine line electrode. Among these methods, in the method using a printing screen, a printing screen having a predetermined pattern is used to pattern-print a conductive paste on a substrate. In the method of etching the electrode, the sintered electrode is coated with a photoresist, exposed, developed and etched to form a patterned electrode. In the method using a photosensitive conductive paste, a photosensitive resin is added to the conductive paste, and the photosensitive conductive paste coated on the substrate is exposed and developed using a mask.

A method of forming electrodes by such a baking method (thick film method) is disclosed in Japanese Unexamined Patent Application Publication Nos. 2003-100001 and 2003-100000. For example, in Patent Document 1, a dispersed conductive paste is patterned on a substrate such as a metal plate, a resin plate, a glass plate, or a ceramic plate, and a powder having electrical conductivity and a resin powder as a binder are formed. It is described that screen-printing a dispersed conductive paste on a substrate is applied to a method of forming an electrode, which is characterized by applying pressure molding to the surface of a material mixed with and simultaneously transferring an electrode pattern (Patent Claim 1 and the constitution of the invention column of Document 1).

Further, Patent Document 2 discloses an electrode paste composition comprising a photopolymerizable monomer, a photopolymerizable initiator, and a metal powder such as silver powder, and a substrate on which the electrode is applied. applying a paste composition for a plasma display panel, arranging a mask, exposing, developing, and baking the paste composition for electrodes patterned on a substrate. A manufacturing method is disclosed (claims 1 and 10 of Patent Document 2).

Japanese Patent Laid-Open No. 1-136306 Japanese Patent Application Laid-Open No. 2008-66268

However, the electrode formation by the conventional baking method (thick film method) has various problems. In other words, the conductive paste used in the baking method often contains organic solvents such as methyl ethyl ketone (MEK), and when the paste is applied and dried, it may cause environmental air pollution and worker health problems. Measures should be taken to prevent failures. Moreover, when forming the pattern electrodes, in many cases, the paste and the electrodes provided in the regions other than the pattern are discarded. Therefore, material loss occurs, leading to an increase in manufacturing costs. In addition, the method using etching or a photosensitive conductive paste requires many complicated steps such as an exposure step and a development step, resulting in a problem of a long cycle time.

The inventors of the present invention have found that a ferrite composite powder composed of specific metal-coated ferrite particles can be used as an electrode-forming material, and that an electrode can be produced by a simple method by using this electrode-forming material. .

The present invention has been completed based on such findings, and aims to provide an electrode-forming material, an electrode manufacturing method, and an electrode that enable electrodes to be formed by a simple technique.

The present invention includes aspects <1> to <9> below.
<1>
An electrode-forming material comprising a ferrite composite powder,
The ferrite composite powder is composed of a plurality of metal-coated ferrite particles,
The ferrite composite powder has a shape factor SF-1 of 100 to 130,
A material, wherein the metal-coated ferrite particles comprise ferrite particles and a coating layer containing a conductive metal provided on the surfaces of the ferrite particles.
<2>
The material according to <1>, wherein the conductive metal contains one or more metals selected from the group consisting of silver (Ag), copper (Cu) and nickel (Ni).
<3>
The material according to <1> or <2>, wherein the coating layer has a thickness of 10 to 1000 nm.
<4>
The material according to any one of <1> to <3>, wherein the ferrite composite powder has a volume average particle size (D50) of 1 to 50 μm.
<5>
The ferrite particles include manganese (Mn)-based ferrite, manganese-zinc (Mn--Zn)-based ferrite, nickel (Ni)-based ferrite, nickel-zinc (Ni--Zn)-based ferrite, nickel-zinc-copper (Ni--Zn -Cu) ferrite, magnesium (Mg) ferrite, magnesium-zinc (Mg-Zn) ferrite, strontium (Sr) ferrite, barium (Ba) ferrite, _manganese -magnesium (Mn-Mg) ferrite, manganese - The material according to any one of <1> to <4>, comprising one or more selected from the group consisting of magnesium-strontium (Mn-Mg-Sr) ferrites.
<6>
A deposition step of depositing the electrode-forming material according to any one of <1> to <5> on a substrate to form a deposit, and sintering the deposit to impart conductivity to the deposit. and a sintering step.
<7>
The method according to <6>, wherein during the deposition step, a magnetic field is applied to the electrode-forming material, and the applied magnetic field aligns the metal-coated ferrite particles in the electrode-forming material to pattern the deposit.
<8>
The method according to <7>, wherein the substrate is a non-magnetic thin plate, and the metal-coated ferrite particles are aligned by an applied magnetic field generated by a magnet provided under the non-magnetic thin plate during the deposition step.
<9>
An electrode comprising a sintered body of the material according to any one of <1> to <5>,
An electrode comprising a matrix made of a conductive metal and ferrite particles dispersed in the matrix.
The present invention includes aspects <1> to <9> above, but hereinafter, other matters (for example, aspects (1) to (10) below ) will also be described . In this specification, the expression "-" includes both numerical values. That is, "X to Y" is synonymous with "X or more and Y or less".

(1) An electrode-forming material containing a ferrite composite powder,
The ferrite composite powder is composed of a plurality of metal-coated ferrite particles,
A material, wherein the metal-coated ferrite particles comprise ferrite particles and a coating layer containing a conductive metal provided on the surfaces of the ferrite particles.

(2) The material according to (1) above, wherein the conductive metal contains one or more metals selected from the group consisting of silver (Ag), copper (Cu) and nickel (Ni).

(3) The material according to (1) or (2) above, wherein the coating layer has a thickness of 10 to 1000 nm.

(4) The material according to any one of (1) to (3) above, wherein the ferrite composite powder has a volume average particle size (D50) of 1 to 50 μm.

(5) The material according to any one of (1) to (4) above, wherein the ferrite composite powder has a shape factor SF-1 of 100 to 130.

(6) The ferrite particles include manganese (Mn)-based ferrite, manganese-zinc (Mn--Zn)-based ferrite, nickel (Ni)-based ferrite, nickel-zinc (Ni--Zn)-based ferrite, nickel-zinc-copper ( Ni-Zn-Cu) based ferrite, magnesium (Mg) based ferrite, magnesium-zinc (Mg-Zn) based ferrite, strontium (Sr) based ferrite, barium (Ba) based ferrite, manganese-magnesium (Mn-Mg) based The material according to any one of (1) to (5) above, comprising one or more selected from the group consisting of ferrite and manganese-magnesium-strontium (Mn--Mg--Sr) ferrite.

(7) depositing the electrode-forming material according to any one of the above (1) to (6) on a substrate to form a deposit; and sintering the deposit to make the deposit conductive. and a sintering step to impart properties.

(8) The method according to (7) above, wherein a magnetic field is applied to the electrode-forming material during the deposition step, and the metal-coated ferrite particles in the electrode-forming material are aligned by the applied magnetic field to pattern the deposit.

(9) The substrate according to (8) above, wherein the substrate is a non-magnetic thin plate, and the metal-coated ferrite particles are aligned by an applied magnetic field generated by a magnet provided under the non-magnetic thin plate during the deposition step. Method.

(10) An electrode comprising a matrix made of a conductive metal and ferrite particles dispersed in the matrix.

ADVANTAGE OF THE INVENTION According to this invention, the electrode formation material which can form an electrode by a simple method, the manufacturing method of an electrode, and an electrode are provided.

An example of means for applying a magnetic field using a magnet is shown. 2 shows an SEM image of a cross section of the electrode of Example 2. FIG.

Electrode Forming Material The electrode forming material of the present invention contains a ferrite composite powder. Ferrite composite powder is composed of a plurality of metal-coated ferrite particles (also referred to as “ferrite composite particles”). That is, the ferrite composite powder is an aggregate of multiple metal-coated ferrite particles. Also, the metal-coated ferrite particles comprise ferrite particles and a coating layer.

In the electrode-forming material of the present invention, the coating layer of the metal-coated ferrite particles contains a conductive metal. This conductive metal functions as a conductive component of the electrode obtained by sintering the electrode-forming material. Therefore, by using the electrode-forming material of the present invention, a highly conductive electrode can be obtained by a simple method.

The electrode-forming material also contains metal-coated ferrite particles. Therefore, by applying a magnetic field at the time of electrode formation, it is possible to pattern the electrode, which is the electrode forming material and its sintered body. That is, the metal-coated ferrite particles contain ferrite particles that are ferromagnetic. Therefore, when a magnetic field is applied, they align (arrange) along the lines of magnetic force. At this time, by adjusting the direction and strength of the magnetic lines of force, the alignment pattern of the ferrite particles can be controlled, and as a result, various patterns can be imparted to the electrode-forming materials and electrodes.

The conductive metal is not particularly limited, but known electrode materials such as silver (Ag), copper (Cu), nickel (Ni), palladium (Pd), and alloys made of combinations thereof can be used. However, the conductive metal preferably comprises one or more metals selected from the group consisting of silver (Ag), copper (Cu) and nickel (Ni). This is because these metals and alloys are inexpensive and have excellent electrical conductivity.

In addition, in this specification, a metal is a concept including an alloy or an intermetallic compound. Therefore, the coating layer may consist only of silver (Ag), copper (Cu) or nickel (Ni), or may be an alloy or intermetallic compound of these metals. Alternatively, it may be an alloy or intermetallic compound containing metals other than silver (Ag), copper (Cu) and nickel (Ni). However, the content of silver (Ag), copper (Cu) and nickel (Ni) in the coating layer (the total amount when multiple types are included) is preferably 50% by mass or more, more preferably 70% by mass or more, 90% by mass or more is more preferable.

When the coating layer consists of only silver (Ag) and copper (Cu), the mass ratio of the content of silver (Ag) to the content of copper (Cu) in the coating layer (content of silver (Ag): The copper (Cu) content) is preferably 5:95 to 95:5, more preferably 15:85 to 85:15.
When the coating layer consists only of silver (Ag) and nickel (Ni), the mass ratio of the content of silver (Ag) to the content of nickel (Ni) in the coating layer (content of silver (Ag): The nickel (Ni) content) is preferably 5:95 to 95:5, more preferably 15:85 to 85:15.
When the coating layer consists only of copper (Cu) and nickel (Ni), the mass ratio of the copper (Cu) content and the nickel (Ni) content in the coating layer (copper (Cu) content: The nickel (Ni) content) is preferably 5:95 to 95:5, more preferably 15:85 to 85:15.

Further, when the coating layer is composed only of silver (Ag), copper (Cu), and nickel (Ni), the following (mode 1) to (mode 4) are preferable.

(Aspect 1)
The content of silver (Ag) in the coating layer is 60 to 80% by mass,
The content of copper (Cu) in the coating layer is 5 to 20% by mass,
The content of nickel (Ni) in the coating layer is 5 to 20% by mass,
The total amount of the silver (Ag) content, the copper (Cu) content, and the nickel (Ni) content is 100% by mass.

(Aspect 2)
The content of silver (Ag) in the coating layer is 5 to 20% by mass,
The content of copper (Cu) in the coating layer is 60 to 80% by mass,
The content of nickel (Ni) in the coating layer is 5 to 20% by mass,
The total amount of the silver (Ag) content, the copper (Cu) content, and the nickel (Ni) content is 100% by mass.

(Aspect 3)
The content of silver (Ag) in the coating layer is 5 to 20% by mass,
The content of copper (Cu) in the coating layer is 5 to 20% by mass,
The content of nickel (Ni) in the coating layer is 60 to 80% by mass,
The total amount of the silver (Ag) content, the copper (Cu) content, and the nickel (Ni) content is 100% by mass.

(Aspect 4)
The content of silver (Ag) in the coating layer is 20 to 50% by mass,
The content of copper (Cu) in the coating layer is 20 to 50% by mass,
The content of nickel (Ni) in the coating layer is 20 to 50% by mass,
The total amount of the silver (Ag) content, the copper (Cu) content, and the nickel (Ni) content is 100% by mass.

The thickness of the coating layer is preferably 10-1000 nm. The thicker the coating layer, the higher the proportion of the conductive component in the ferrite composite powder, and the higher the conductivity of the electrode. On the other hand, if the coating layer is too thick, the proportion of ferrite grains will decrease. The thickness of the coating layer is more preferably 50-500 nm, still more preferably 100-200 nm.
The thickness of the coating layer (also referred to as the metal coating layer) can be measured by observing the cross section of the ferrite composite particles. Specifically, it is as follows.
The thickness of the coating layer can be measured by observing the cross section of the ferrite composite particles with a scanning electron microscope (SEM). Specifically, 9 g of the powder to be measured and 1 g of powdered resin were placed in a 50 cc glass bottle and mixed for 30 minutes in a ball mill. After that, the molded body was embedded in resin while standing vertically so that the cross section of the molded body could be seen, and polished with a polishing machine to obtain a sample for thickness measurement. Next, 20 particles of the prepared sample for thickness measurement are photographed with an SEM at a magnification of 500 to 5000 times (magnification in which about one particle fits in one field of view). After that, the entire cross section of the particle was subjected to elemental analysis by EDX, and the presence of the coating layer was determined. The average thickness was taken as the thickness of the coating layer.
For SEM, SU-8020 manufactured by Hitachi High-Technologies Corporation was used, and an acceleration voltage of 1 KV was taken in LA mode. EDX was used by X-MAX manufactured by Horiba, Ltd., and image information was obtained from the SEM in an acceleration voltage of 15 KV and LA mode. Particle analysis was performed while obtaining.
Kynar301F manufactured by Arkema was used as the powder resin.

The coating layer may be formed uniformly or may be formed non-uniformly. The coverage of the particles should be 50% or more of the surface area of the particles, preferably 70% or more. Here, the coverage rate is obtained by taking a cross-sectional SEM photograph of the particle, and the coverage rate = the portion where the metal coating layer exists (length) / the peripheral length of the composite particle × 100 (%), and a plurality of particles of at least 100 particles Calculated by averaging the calculated coverage ratios. Specifically, image analysis is performed on the cross-sectional SEM photograph obtained, the area of the metal coating layer present on the particle surface is calculated, and the portion (length) where the metal coating layer is present = area of the metal coating layer / The portion (length) where the metal coating layer exists is obtained by setting it as the thickness of the metal coating layer. The thickness of the metal coating layer is determined by the method described above. The perimeter of the particle is also determined by image analysis. In addition, when the thickness of the metal coating layer is extremely thin, the coverage may exceed 100% by calculation, but in such a case, it shall be 100%.

The coating layer may contain components other than the conductive metal. Examples of such components include components derived from the underlying layer provided during the formation of the coating layer. However, from the viewpoint of obtaining a highly conductive electrode, the content of the conductive metal is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 99% by mass or more. .

The metal-coated ferrite particles may have layers other than the coating layer. Therefore, an intermediate layer may be provided between the ferrite particles and the coating layer, and a surface layer may be provided on the coating layer. Examples of such an intermediate layer include an underlayer provided when forming the coating layer and an adhesion layer for improving adhesion between the ferrite particles and the coating layer. Examples of the underlying layer include a palladium (Pd)-containing layer. Further, the surface layer includes a surface treatment layer for improving properties such as fluidity of the ferrite composite powder.

The volume average particle diameter (D50) of the ferrite composite powder is preferably 1 to 50 μm. By setting the volume average particle size to 1 μm or more, the fluidity of the particles can be enhanced. This is because particles with an excessively small volume-average particle size tend to agglomerate. The volume average particle size is more preferably 10 µm or more, and even more preferably 15 µm or more. On the other hand, by setting the volume average particle size to 50 μm or less, a dense electrode can be obtained. This is because particles with an excessively large particle diameter tend to generate large voids when deposited. The volume average particle size is more preferably 40 μm or less, and even more preferably 30 μm or less.

The volume average particle size (D50), volume average particle size (D10), and volume average particle size (D90) of the ferrite composite powder were measured as follows. First, 10 g of a sample and 80 ml of water were placed in a 100 ml beaker, and two drops of sodium hexametaphosphate were added as a dispersant. Then, dispersion was carried out using an ultrasonic homogenizer (Model UH-150, SMT Co., Ltd.). At this time, the output level of the ultrasonic homogenizer was set to 4, and dispersion was performed for 20 seconds. Thereafter, bubbles formed on the surface of the peaker were removed, and measurement was performed by introducing it into a laser diffraction particle size distribution analyzer (Shimadzu Corporation, SALD-7500nano). From this measurement, the 10% diameter (volume average particle diameter (D10)), 50% diameter (volume average particle diameter (D50)) and 90% diameter (volume average particle diameter (D90)) in volume particle size distribution were determined. Here, the measurement conditions were a pump speed of 7, a built-in ultrasonic wave irradiation time of 30, and a refractive index of 1.70-050i.

The volume average particle size (D10) of the ferrite composite powder is preferably 0.1 to 30 μm, more preferably 1 to 20 μm, even more preferably 3 to 10 μm.
The volume average particle size (D90) of the ferrite composite powder is preferably 15 to 80 μm, more preferably 15 to 60 μm, even more preferably 15 to 45 μm.

The shape of the particles in the ferrite composite powder is not limited and may be any shape. However, the shape is preferably spherical or polyhedral. By using spherical or polyhedral particles, the fluidity of the particles is enhanced, and a dense electrode can be obtained.

The shape factor SF-1 of the ferrite composite powder is preferably 100-130. SF-1 is an index of particle sphericity. SF-1 is 100 for a perfect sphere, and increases with distance from the sphere. By setting SF-1 to 130 or less, the fluidity of the particles is enhanced. SF-1 is more preferably 120 or less, even more preferably 110 or less.

The shape factor SF-2 of the ferrite composite powder is preferably 100-120. SF-2 is an index showing the degree of unevenness of the particle surface. SF-2 is 100 if there is no unevenness on the surface, and increases as the unevenness becomes deeper. By setting SF-2 to 120 or less, it means that a metal coating layer is formed uniformly with little unevenness on the surface. An effect of hastening the formation of a network of metal elements can be expected. On the other hand, if the unevenness is excessively deep, the fluidity of the particles is hindered. Therefore, by setting the SF-2 to 120 or less, the fluidity of the particles for forming the electrode is improved, and it becomes possible to achieve a higher density of the electrode. The shape factor SF-2 is more preferably 100-118, even more preferably 100-115.

The shape factors SF-1 and SF-2 can be obtained, for example, as follows. That is, the ferrite composite particles are observed with a scanning electron microscope (SEM), and the maximum particle length (horizontal Feret diameter) R (unit: μm), projected perimeter L (unit: μm) and projected area S (unit: μm ² ). After that, SF-1 and SF-2 of the particles are calculated according to the following formulas (1) and (2). The SF-1 and SF-2 of the particles are obtained by performing the same operation for a plurality of particles, and the average value is calculated to obtain the SF-1 and SF-2 of the ferrite composite powder.
Formula (1): SF-1 = (R ² /S) x (π/4) x 100,
Formula (2): SF-2=(L ² /S/4π)×100

The true density of the ferrite composite powder is preferably 5 g/cm ³ or more and 8 g/cm ³ or less, more preferably 5.2 g/cm ³ or more and 7.5 g/cm ³ or less.
The true density of the ferrite composite powder was measured according to JIS Z 8807:2012 using a fully automatic true density measuring device Macpycno manufactured by Mountech.

The tap density of the ferrite composite powder is preferably 3.0 g/cm ³ or more and 5.5 g/cm ³ or less, more preferably 3.2 g/cm ³ or more and 5.0 g/cm ³ or less.

In this specification, the tap density refers to the density determined by measurement in compliance with JIS R1628.
As a tapping device, a USP tap density measuring device (Powder Tester PT-X, manufactured by Hosokawa Micron Corporation) can be used.

Ferrite particles mainly contain a ferrite component. Here, "mainly containing" means that the content of the ferrite component is 50% by mass or more. By increasing the content of the ferrite component, it is possible to sufficiently exhibit the effects based on ferrite.

The composition of the ferrite particles is not particularly limited as long as it exhibits ferromagnetism. However, ferrite particles are manganese (Mn)-based ferrite, manganese-zinc (Mn--Zn)-based ferrite, nickel (Ni)-based ferrite, nickel-zinc (Ni--Zn)-based ferrite, nickel-zinc-copper (Ni-- Zn—Cu) based ferrite, magnesium (Mg) based ferrite, magnesium-zinc (Mg—Zn) based ferrite, strontium (Sr) based ferrite, barium (Ba) based ferrite, manganese-magnesium (Mn—Mg) based ferrite, It is preferably composed of one or more selected from the group consisting of manganese-magnesium-strontium (Mn--Mg--Sr) ferrites. Among them, strontium (Sr)-based ferrite and barium (Ba)-based ferrite are mainly hard ferrites, and the others are soft ferrites. Ferrite particles having such a composition have a high magnetization. Therefore, when the pattern electrodes are applied, they are sufficiently aligned without applying an extremely strong magnetic field.

More specifically, as the Mn-based ferrite, for example, one containing 48% by mass or more and 69% by mass or less of Fe and 1.5% by mass or more and 24% by mass or less of Mn can be used.
The Mn—Zn ferrite contains, for example, 47% by mass to 61% by mass of Fe, 7.5% by mass to 23% by mass of Mn, and 1% by mass to 14% by mass of Zn. can be used.

The Ni—Zn ferrite contains, for example, 45% by mass to 50% by mass of Fe, 2% by mass to 25% by mass of Ni, and 2.5% by mass to 23% by mass of Zn. can be used.
The Ni—Zn—Cu ferrite contains, for example, 45% by mass to 50% by mass of Fe, 4% by mass to 10% by mass of Ni, 10% by mass to 20% by mass of Zn, and 0.5% by mass of Cu. It is possible to use one containing at a content rate of 7% by mass or less.

As the Sr-based ferrite, for example, one containing 61% by mass or more and 65% by mass or less of Fe and 7% by mass or more and 10% by mass or less of Sr can be used.

The Mn—Mg ferrite contains, for example, 45% by mass to 55% by mass of Fe, 4% by mass to 24% by mass of Mn, and 0.1% by mass to 12% by mass of Mg. can be used.

As the Mn-Mg-Sr ferrite, for example, Fe is 45% by mass or more and 55% by mass or less, Mn is 4% by mass or more and 24% by mass or less, Mg is 0.1% by mass or more and 12% by mass or less, and Sr is 0%. It is possible to use one containing at a content rate of more than 3% by mass or less.

The electrode-forming material may contain components other than the ferrite composite powder. For example, conductive metal powders such as silver (Ag) powder, copper (Cu) powder and nickel (Ni) powder may be included to enhance the conductivity of the electrode. Further, a flux consisting of glass powder and other additives may be included. However, from the viewpoint of enhancing the effect of patterning by applying a magnetic field, the ratio of the ferrite composite powder in the electrode forming material is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The electrode-forming material may consist of only the ferrite composite powder.

Moreover, the electrode-forming material may be in any form of dry powder, slurry containing a solvent, and paste containing a solvent and an organic binder. However, the slurry or paste requires a drying treatment to remove the solvent and a binder removal treatment to remove the organic binder. Therefore, from the viewpoint of process simplification, the electrode-forming material is preferably dry powder containing no solvent or organic binder.

Manufacture of Electrode-Forming Material Next, a method of manufacturing the electrode-forming material will be described. To produce the electrode-forming material, first, a ferrite composite powder is produced. A method for producing a ferrite composite powder includes a step of producing a ferrite powder composed of ferrite particles, and a step of forming a coating layer on the ferrite particles. Each step will be described below.

<Production of ferrite powder>
Ferrite powder may be produced by a known method. For example, raw materials are mixed, the mixture is calcined, the calcined material is pulverized, the pulverized material is granulated, and the granulated material is thermally sprayed or fired. As raw materials, known ferrite raw materials such as oxides, carbonates, hydroxides and chlorides can be used. In addition, the raw materials are mixed using a known mixer such as a Henschel mixer, and may be performed by either one or both of a dry method and a wet method.

Next, the obtained raw material mixture is calcined to obtain a calcined product. Temporary baking is performed by a well-known method. For example, a furnace such as a rotary kiln, a continuous furnace, or a batch furnace may be used. The calcination conditions may also be known conditions. For example, it may be carried out at a temperature of 700 to 1300° C. in an air atmosphere.

Thereafter, the obtained calcined material is pulverized and granulated to obtain granules. A pulverization method is not particularly limited. For example, using a pulverizer such as a vibrating mill, a ball mill, or a bead mill, either one or both of a dry method and a wet method are used. The granulation method may also be a known method. For example, to the calcined product after pulverization, water, if necessary, a binder such as polyvinyl alcohol, and additives such as a dispersant and / or an antifoaming agent are added to adjust the viscosity. Use a granulator. Further, if necessary, the obtained granules may be subjected to binder removal treatment to remove organic components such as binders. The conditions for the binder removal treatment may be determined depending on the type of the organic component such as the binder.

Next, the obtained granules are thermally sprayed or sintered to produce a thermally sprayed material or a sintered material.

When producing a thermal spray by thermal spraying, a mixed gas of combustion gas and oxygen can be used as the combustible gas combustion flame. The volume ratio of combustion gas to oxygen is preferably 1:3.5 to 1:6.0. Formation of particles with a small particle size by condensation of the volatilized material can be favorably promoted. Moreover, the shape of the obtained ferrite particles can be suitably adjusted. Furthermore, it is possible to omit or simplify the treatment such as classification in the subsequent steps, and to further improve the productivity of the ferrite particles. For example, it can be used at a ratio of 35 Nm ^{3 /} hr to 60 Nm ³ /hr of oxygen to 10 Nm 3 /hr of combustion gas.

Propane gas, propylene gas, acetylene gas, etc. are mentioned as combustion gas used for thermal spraying. Among them, propane gas can be preferably used. Nitrogen, oxygen, air, or the like can be used as a carrier gas in order to carry the granules into the combustible gas. The flow velocity of the conveyed granules is preferably 20-60 m/sec. Further, thermal spraying is preferably carried out at a temperature of 1000-3500°C, more preferably 2000-3500°C.

By satisfying these conditions, the formation of relatively small particles by condensation of the volatilized material can proceed more favorably. Moreover, the shape of the ferrite particles to be obtained can be more preferably adjusted. Furthermore, it is possible to omit or simplify the treatment such as classification in the subsequent steps, and to further improve the productivity of the ferrite particles. In addition, it is possible to reduce the proportion of particles to be removed by classification in the subsequent step, and to further improve the yield of ferrite particles.

The particles thus thermally sprayed and ferritized are quenched and solidified in water or in an air atmosphere and collected by a cyclone and/or filter. After that, the ferrite particles collected by the cyclone and/or the repair filter are classified as necessary. As a classification method, existing air classification, mesh filtration method, sedimentation, etc. are used to adjust the particle size to a desired particle size. In addition, it is also possible to separate and collect|recover the particle|grains with a large particle size with a cyclone etc.

On the other hand, when producing a fired product by main firing, the granulated product is placed in an existing furnace such as a batch furnace or a continuous furnace, and the main firing is performed. The firing conditions are not generally limited, and may be determined according to the composition of the ferrite particles. One example is a condition of holding at a temperature of 800 to 1500° C. for 1 to 24 hours in an air atmosphere. In addition, the oxygen concentration in the furnace may be adjusted during main firing. Furthermore, if necessary, the fired product obtained may be pulverized using a known pulverizer such as a hammer mill.

If necessary, the obtained sprayed material or fired material may be pulverized and then classified to remove coarse particles and fine particles. For crushing, a known crusher such as a hammer mill may be used. Classification may also be performed by a known method. For example, there is a method of classifying using a sieve and then classifying with an air stream. Thus, a ferrite powder composed of ferrite particles is produced.

<Formation of coating layer>
The coating layer is formed by subjecting the obtained ferrite powder (ferrite particles) to electroless plating with a conductive metal. Electroless plating may be performed by a known method. Also, prior to the formation of the coating layer, an underlayer may be formed on the ferrite particles. Thus, a ferrite composite powder composed of metal-coated ferrite particles is produced.

If necessary, other conductive metal powder, flux and/or additives are added to the ferrite composite powder to obtain an electrode forming material.

Method for Producing Electrode The method for producing an electrode according to the present invention includes a deposition step of depositing an electrode-forming material on a substrate to form a deposit, and a sintering step of sintering the deposit to impart conductivity to the deposit. and Each step will be described below.

<Deposition process>
In the deposition step, the electrode-forming material is deposited on the substrate to form a deposit. The deposition method is not particularly limited. For example, a method of supplying the electrode-forming material from a nozzle and naturally depositing it on the substrate can be mentioned. Alternatively, a method of spraying the electrode-forming material onto the substrate in an air stream can be used.

Preferably, a magnetic field is applied to the electrode-forming material during the deposition step, and the applied magnetic field aligns the metal-coated ferrite particles in the electrode-forming material. Thus, the deposit (electrode forming material) is patterned. The magnetic field may be applied to the electrode-forming material during deposition or may be applied to the electrode-forming material after deposition (deposit). In either case, the metal-coated ferrite particles in the electrode-forming material are aligned.

The means for generating the applied magnetic field is not limited as long as the desired pattern can be obtained. However, from the viewpoint of simplicity, it is preferable to use permanent magnets. Known magnets such as ferrite magnets and rare earth magnets can be used as permanent magnets. Also, it may be a sintered magnet or a bonded magnet. A developing method such as magnetography may also be used.

FIG. 1 shows an example of means for applying a magnetic field using a magnet. In FIG. 1, a magnet (2) is provided directly below a substrate (1). Here, the substrate (1) consists of a non-magnetic thin plate, and the magnet (2) is a thin plate magnet. The substrate (non-magnetic thin plate) (1) is arranged so that its thickness faces the vertical direction, and the magnet (thin plate magnet) (2) is arranged so that its thickness faces the horizontal direction. The magnet (thin plate magnet) (2) is magnetized so that the first surface (3) is N pole and the second surface (4) facing the first surface (3) is S pole. Therefore, the magnetic lines of force (5) extend outside the magnet (2) along the direction from the N pole to the S pole. In FIG. 1, only the lines of magnetic force (5) passing over the magnet (2) are indicated by arrows, and other lines of magnetic force are omitted.

Since the substrate (1) is made of a non-magnetic thin plate, the lines of magnetic force (5) pass through the substrate (non-magnetic thin plate) (1). Therefore, when the electrode-forming material is deposited on the substrate (1), the metal-coated ferrite particles (6) therein are aligned under the influence of the magnetic lines of force (5). In the example shown in FIG. 1, the metal-coated ferrite particles (6) are aligned along one side of the magnet (2) directly below the substrate (1). Therefore, the electrode-forming material (deposit) containing the metal-coated ferrite particles (6) is patterned into fine lines.

The shape of the magnet (2) may be square plate-like, disk-like, or arbitrary polygonal plate-like. For example, by making the magnet (2) disk-shaped, it is possible to supply the electrode-forming material onto the substrate (1) while rotating the magnet. On the other hand, it is preferable that the magnet (2) has a large ratio of the length (width, length, diameter, etc.) in other directions to its thickness, that is, the plate-like ratio. This is because if the plate ratio is too small, the influence of magnetic lines of force directed in undesired directions cannot be ignored. Such undesired magnetic lines of force cause misalignment of the metal-coated ferrite grains. Therefore, the plate-like ratio (ratio of length in other directions to thickness) of the magnet (2) is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more.

The material of the substrate (1) is not limited as long as it is non-magnetic. Examples thereof include resin films such as polyamideimide, epoxy resin, polyethylene terephthalate (PET), ceramic thin plates, and non-magnetic metal thin plates. On the other hand, it is preferable that the thickness of the substrate (1) is thin. This is because if the substrate (1) is too thick, a magnetic field sufficient to align the metal-coated ferrite particles will not be applied to the electrode-forming material. The upper limit of the thickness of the substrate (1) is not generally limited by the strength of the magnetic field generated by the magnet used. However, the thickness is preferably 10 mm or less, more preferably 5 mm or less, even more preferably 1 mm or less.

Another example of means for applying a magnetic field using a magnet is a method using the magnet itself as a substrate. In this technique, an electrode-forming material is supplied onto a magnet, which is a substrate. Electrode-forming materials containing metal-coated ferrite particles are attracted and deposited on the magnetic poles of the magnet. A patterned deposit can be obtained by transferring the deposited electrode-forming material to another substrate.

Thus, it is preferable to apply a magnetic field to the electrode-forming material during the deposition process, thereby patterning the deposit (electrode-forming material), and as a result, through the subsequent sintering process, a patterned electrode is obtained. be able to. However, the electrode manufacturing method of the present invention is not limited to a mode in which a magnetic field is applied in the deposition process. A highly conductive electrode can be obtained through the sintering process without applying a magnetic field.

<Sintering process>
In the sintering step, the deposit (electrode-forming material) is sintered (fired) to impart electrical conductivity to the deposit to form an electrode. Sintering bonds and integrates the coating layer (conductive metal) of the metal-coated ferrite particles. Therefore, in the electrode after sintering, a three-dimensionally continuous metal matrix made of a conductive metal is formed, and the conductivity of the deposit (electrode) is developed.

The method of sintering is not limited as long as an electrode having desired conductivity can be obtained. When the substrate is made of a heat-resistant material such as a ceramic thin plate or a non-magnetic metal thin plate, it is possible to sinter the deposit together with the substrate in a sintering furnace. On the other hand, when the substrate is made of a non-heat-resistant material such as a resin film, it is preferable to use the photobaking method in order to minimize damage to the substrate.

The lower limit of the sintering temperature is determined by the material of the conductive metal, the composition of the electrode-forming material, etc., and is not generally limited. However, from the viewpoint of promoting bonding of the coating layer (conductive metal), an excessively low sintering temperature is not preferred. The sintering temperature is preferably 600° C. or higher, more preferably 700° C. or higher, and even more preferably 800° C. or higher. Moreover, the upper limit of the sintering temperature is determined by the composition of the ferrite particles, the components of the electrode-forming material, and the like, and is not generally limited. However, if the sintering temperature is excessively high, the conductive metal in the coating layer may diffuse into the ferrite particles, or only the coated metal may agglomerate, resulting in failure to obtain the conductivity of the electrode. The sintering temperature is preferably 1350° C. or lower, more preferably 1320° C. or lower, and even more preferably 1300° C. or lower. Moreover, the sintering holding time is preferably 1 minute to 2 hours.

Sintering is preferably performed in an atmosphere in which the conductive metal forming the coating layer is not oxidized. This is because the conductivity of the electrode deteriorates when the conductive metal is oxidized. Such an atmosphere includes a weakly reducing atmosphere (for example, a mixed gas of hydrogen gas and an inert gas), a low-oxygen atmosphere, an oxygen-free atmosphere, a vacuum atmosphere, and an inert gas atmosphere. The oxygen concentration in the atmosphere is preferably 10% by volume or less, more preferably 5% by volume or less, and even more preferably 1% by volume or less.

Thus, electrodes are formed from the electrode-forming material. The resulting electrode comprises a matrix of conductive metal and ferrite particles dispersed therein. A metal matrix made of a conductive metal has a three-dimensional continuous structure. Therefore, the electrodes exhibit high conductivity. Also, a patterned electrode can be obtained by applying a magnetic field to the electrode-forming material in the deposition process.

Electrodes The present invention also relates to electrodes. The electrode of the present invention includes a matrix made of a conductive metal and ferrite particles dispersed in the matrix. Although the method for producing the electrode of the present invention is not particularly limited, for example, the electrode may be produced by the method for producing the electrode described above.
After the electrode is formed, the matrix and the ferrite particles dispersed in the matrix can be confirmed by using a scanning electron microscope (SEM) in the cross section of the electrode.

The invention is further illustrated by the following examples.

Example 1 (Nickel (Ni) coating layer)
(1) Production of ferrite composite powder (ferrite composite particles) <Raw material mixing>
Iron oxide (Fe ₂ O ₃ ) and manganese tetroxide (Mn ₃ O ₄ ) were used as raw materials, weighed at a ratio of 80 mol of Fe ₂ O ₃ and 6.67 mol of Mn ₃ O ₄ , and a Henschel mixer was used. mixed.

<Temporary firing and pulverization>
The resulting mixture was calcined in air at 950° C. for 4 hours using a rotary kiln. The obtained calcined product is coarsely pulverized using a dry bead mill (5/8 inch steel ball beads), then water is added and finely pulverized using a wet bead mill (3/8 inch zirconia beads). to obtain a slurry. The resulting slurry had a solid content concentration of 55% by mass, and the particle size of pulverized powder in the slurry (slurry particle size) was 2.42 μm.

<Granulation>
To the obtained slurry, polyvinyl alcohol (PVA) was added as a binder in an amount of 0.3% by weight in terms of solid content, and further 0.25% by weight of a dispersant (polycarboxylic acid compound) and an antifoaming agent (polyhydric alcohol compound) were added. 0.2 wt% was added. Thereafter, the slurry to which the dispersant and antifoaming agent were added was granulated using a spray dryer to obtain granules.

<Thermal spraying>
The granules obtained were sprayed and quenched in a combustible gas combustion flame. Thermal spraying was performed under the conditions of a propane gas flow rate of 7 m ³ /hour and an oxygen flow rate of 35 m ³ /hour. At this time, since the granules were thermally sprayed while continuously flowing, the particles after thermal spraying and quenching were independent of each other without sticking together. Subsequently, the cooled particles were recovered by a cyclone provided downstream of the air stream to obtain a thermal spray. A sieve was used to remove fine powder from the obtained thermal sprayed material, and air stream classification was performed to obtain a ferrite powder composed of manganese (Mn) ferrite particles.

<Formation of coating layer>
By subjecting the ferrite powder (ferrite particles) to electroless plating, a ferrite composite powder composed of metal-coated ferrite particles having a nickel (Ni) coating layer on the surface was obtained. The resulting ferrite composite powder had a nickel (Ni) coating layer with a thickness of 200 nm. This ferrite composite powder was used as an electrode forming material.

(2) Formation of electrodes <Deposition process>
10% by mass of the obtained electrode-forming material was dispersed and mixed in 90% by mass of a PVA aqueous solution, and the mixture was coated on a substrate using a bar coater to form a deposit. At this time, a magnetic field was applied to the deposit using the magnetic field application means shown in FIG. An alumina plate having a thickness of 0.635 m was used as a substrate. A bonded magnet having a thickness of 0.5 mm, a width of 50 mm, and a height of 50 mm was used as the magnet. By applying a magnetic field, the electrode-forming material was aligned, and a fine-line-patterned deposit was obtained.
The concentration of PVA in the PVA aqueous solution was 10% by mass.
Dispersion mixing was carried out using a rotation/revolution type stirring and mixing device for a mixing time of 1 minute.

<Sintering process>
After the moisture content of the obtained deposit was dried, it was sintered together with the substrate using an electric furnace to obtain an electrode. Sintering was performed at 1300° C. in an atmosphere with an oxygen concentration of 0% by volume. The electrodes had a fine line pattern.

Example 2 (copper (Cu) coating layer)
(1) Production of Ferrite Composite Powder (Ferrite Composite Particles) Ferrite composite powder was produced in the same manner as in Example 1, except that a copper (Cu) coating layer was formed instead of the nickel (Ni) coating layer. The obtained ferrite composite powder had a copper (Cu) coating layer with a thickness of 200 nm. This ferrite composite powder was used as an electrode forming material.

(2) Formation of Electrodes Using the obtained electrode-forming material, electrodes were formed in the same manner as in Example 1, except that the firing conditions were 850° C. for 2 hours. The electrodes had a fine line pattern.

Example 3 (silver (Ag) coating layer)
(1) Production of ferrite composite powder (ferrite composite particles) <Raw material mixing>
Iron oxide (Fe ₂ O ₃ ), manganese tetroxide (Mn ₃ O ₄ ), magnesium hydroxide (Mg(OH) ₂ ) and strontium carbonate (SrCO ₃ ) were used as raw materials, Fe ₂ O ₃ : 50 mol, Mn ₃ O ₄ : 13.30 mol, Mg(OH) ₂ : 10 mol and SrCO ₃ : 0.2 mol were weighed and mixed using a Henschel mixer.

<Temporary firing and pulverization>
The resulting mixture was calcined in air at 950° C. for 4 hours using a rotary kiln. The obtained calcined product was coarsely pulverized using a dry bead mill, and then water was added and finely pulverized using a wet bead mill. The obtained slurry had a solid content concentration of 55% by mass, and the particle size of pulverized powder in the slurry (slurry particle size) was 1.85 μm.

<Granulation>
Polyvinyl alcohol (PVA) was added as a binder in an amount of 0.3% by mass in terms of solid content, and a dispersant and an antifoaming agent were added to the resulting slurry. After that, the slurry to which the dispersant and antifoaming agent were added was granulated using a spray dryer.

<Thermal spraying>
The granules obtained were sprayed and quenched in a combustible gas combustion flame. Thermal spraying was performed under the conditions of a propane gas flow rate of 7 m ³ /hour and an oxygen flow rate of 35 m ³ /hour. At this time, since the granules were thermally sprayed while continuously flowing, the particles after thermal spraying and quenching were independent of each other without sticking together. Subsequently, the cooled particles were recovered by a cyclone provided downstream of the air stream to obtain a thermal spray. Fine powder is removed from the obtained sprayed material using a sieve, and further air classified to manganese (Mn)-magnesium (Mg)-strontium (Sr)-based ferrite particles containing magnesium (Mg) and strontium (Sr). A structured ferrite powder was obtained.

<Formation of coating layer>
By subjecting the ferrite powder (ferrite particles) to electroless plating, a ferrite composite powder composed of metal-coated ferrite particles having a silver (Ag) coating layer on the surface was obtained. The resulting ferrite composite powder had a silver (Ag) coating layer with a thickness of 200 nm. This ferrite composite powder was used as an electrode forming material.

(2) Formation of Electrodes Using the obtained electrode-forming material, electrodes were formed in the same manner as in Example 1, except that the firing conditions were 850° C. for 2 hours. The electrodes had a fine line pattern.

Example 4 (ferrite powder without coating layer)
(1) Production of ferrite composite powder (ferrite composite particles) <Raw material mixing>
Iron oxide (Fe ₂ O ₃ ) and manganese tetroxide (Mn ₃ O ₄ ) were used as raw materials, weighed at a ratio of 80 mol of Fe ₂ O ₃ and 6.67 mol of Mn ₃ O ₄ , and a Henschel mixer was used. mixed.

<Temporary firing and pulverization>
The resulting mixture was calcined in air at 950° C. for 4 hours using a rotary kiln. The obtained calcined product is coarsely pulverized using a dry bead mill (5/8 inch steel ball beads), then water is added and finely pulverized using a wet bead mill (3/8 inch zirconia beads). to obtain a slurry. The resulting slurry had a solid content concentration of 55% by mass, and the particle size of pulverized powder in the slurry (slurry particle size) was 2.42 μm.

<Granulation>
To the obtained slurry, polyvinyl alcohol (PVA) was added as a binder in an amount of 0.3% by weight in terms of solid content, and further 0.25% by weight of a dispersant (polycarboxylic acid compound) and an antifoaming agent (polyhydric alcohol compound) were added. 0.2 wt% was added. Thereafter, the slurry to which the dispersant and antifoaming agent were added was granulated using a spray dryer to obtain granules.

<Thermal spraying>
The granules obtained were sprayed and quenched in a combustible gas combustion flame. Thermal spraying was performed under the conditions of a propane gas flow rate of 7 m ³ /hour and an oxygen flow rate of 35 m ³ /hour. At this time, since the granules were thermally sprayed while continuously flowing, the particles after thermal spraying and quenching were independent of each other without sticking together. Subsequently, the cooled particles were recovered by a cyclone provided downstream of the air stream to obtain a thermal spray. A sieve was used to remove fine powder from the obtained thermal sprayed material, and air stream classification was performed to obtain a ferrite powder composed of manganese (Mn) ferrite particles.

(2) Formation of Electrodes Using the obtained electrode-forming material, electrodes were formed in the same manner as in Example 1, but since there was no metal coating, the thin line pattern formed on the substrate after sintering could not be maintained.

[Evaluation of electrode forming material]
Various properties of the electrode-forming materials (ferrite composite powders) obtained in Examples 1 to 4 were evaluated as follows.

<Magnetic properties>
The magnetic properties (saturation magnetization (σs), residual magnetization (σr) and coercive force (Hc)) of the ferrite composite powder were measured as follows. First, a sample was packed in a cell having an inner diameter of 5 mm and a height of 2 mm, and set in a vibrating sample magnetometer (VSM-C7-10A, manufactured by Toei Kogyo Co., Ltd.). Next, an applied magnetic field was applied and swept up to 5 kOe, and then the applied magnetic field was decreased to draw a hysteresis curve. After that, the saturation magnetization σs, remanent magnetization σr and coercive force Hc of the sample were obtained from the data of this curve. Hc was also measured in the same manner. Table 1 shows the saturation magnetization σs, residual magnetization σr and coercive force Hc of the ferrite powder (ferrite particles).

<Elemental analysis (metal content)>
The metal component content of the ferrite composite powder was measured as follows. First, 0.2 g of a sample was weighed, and after adding 20 ml of 1N hydrochloric acid and 20 ml of 1N nitric acid to 60 ml of pure water, the mixture was heated to prepare an aqueous solution in which the sample was completely dissolved. The resulting aqueous solution was set in an ICP analyzer (ICPS-10001V, manufactured by Shimadzu Corporation) to measure the content of metal components.
Similarly, the metal component content of the ferrite powder (ferrite particles) included in the ferrite composite powder was also measured. Table 1 shows the metal component content of the ferrite powder (ferrite particles).

<True Density>
The true density of the ferrite composite powder was measured according to JIS Z 8807:2012 using a fully automatic true density measuring device Macpycno manufactured by Mountech.

<Tap density>
The tap density of ferrite composite powder refers to the density obtained by measurement according to JIS R1628.
As a tapping device, a USP tap density measuring device (Powder Tester PT-X, manufactured by Hosokawa Micron Corporation) was used.

<Particle size distribution>
The particle size distribution of the ferrite composite powder was measured as follows. First, 10 g of a sample and 80 ml of water were placed in a 100 ml beaker, and two drops of sodium hexametaphosphate were added as a dispersant. Then, dispersion was carried out using an ultrasonic homogenizer (Model UH-150, SMT Co., Ltd.). At this time, the output level of the ultrasonic homogenizer was set to 4, and dispersion was performed for 20 seconds. Thereafter, bubbles formed on the surface of the peaker were removed, and measurement was performed by introducing it into a laser diffraction particle size distribution analyzer (Shimadzu Corporation, SALD-7500nano). From this measurement, the 10% diameter (volume average particle diameter (D10)), 50% diameter (volume average particle diameter (D50)) and 90% diameter (volume average particle diameter (D90)) in volume particle size distribution were determined. Here, the measurement conditions were a pump speed of 7, a built-in ultrasonic wave irradiation time of 30, and a refractive index of 1.70-050i.

<Shape factor>
The shape factors (SF-1 and SF-2) of the ferrite composite powder were measured as follows. First, samples were observed using a scanning electron microscope (SU-8020, Hitachi High-Technologies Corporation) and an energy dispersive X-ray spectrometer (EDX; E-MAX, Horiba, Ltd.). The magnification was set to 1000 times during observation. After that, using the particle analysis function attached to EDX, the maximum length (horizontal Feret diameter) R (unit: μm), projected perimeter L (unit: μm) and projected area S (unit: μm ² ) of 100 particles in the sample was automatically measured.

Next, for each particle, SF-1 and SF-2 are calculated according to the following formulas (1) and (2), and the average value for 100 particles is the powder SF-1 and SF-2, respectively. and
Formula (1): SF-1 = (R ² /S) x (π/4) x 100
Formula (2): SF-2=(L ² /S/4π)×100

<Thickness of coating layer>
The thickness of the coating layer was determined as follows.
The thickness of the coating layer was measured by observing the cross section of the ferrite composite particles with a scanning electron microscope (SEM). Specifically, 9 g of the powder to be measured and 1 g of powdered resin were placed in a 50 cc glass bottle and mixed for 30 minutes in a ball mill. After that, the molded body was embedded in resin while standing vertically so that the cross section of the molded body could be seen, and polished with a polishing machine to obtain a sample for thickness measurement. Next, 20 particles of the prepared sample for thickness measurement are photographed with an SEM at a magnification of 500 to 5000 times (magnification in which about one particle fits in one field of view). After that, the entire cross section of the particle was subjected to elemental analysis by EDX, and the presence of the coating layer was determined. The average thickness was taken as the thickness of the coating layer.
For SEM, SU-8020 manufactured by Hitachi High-Technologies Corporation was used, and an acceleration voltage of 1 KV was taken in LA mode. EDX was used by X-MAX manufactured by Horiba, Ltd., and image information was obtained from the SEM in an acceleration voltage of 15 KV and LA mode. Particle analysis was performed while obtaining.
Kynar301F manufactured by Arkema was used as the powder resin.

[result]
In Examples 1 to 4, the evaluation results of the ferrite composite powder (electrode-forming material) were as shown in Table 2. It was confirmed that the ferrite composite powders of Examples 1 to 3 had a high saturation magnetization (σs) even after metal coating and were sufficiently usable. Further, as a result of elemental analysis, nickel (Ni), copper (Cu), or silver (Ag), which is a component of the coating layer, was detected, confirming the formation of the coating layer. It was also found that the ferrite composite powder has small shape factors SF-1 and SF-2 (close to 100) and consists of spherical particles with little surface unevenness. Furthermore, it was found that the ferrite composite powder has a relatively high tap density and is excellent in fluidity and fillability.

A continuity test was conducted on the thin line patterns on the substrates of the electrodes obtained in Examples 1-3.
Conductivity test was conducted using a Keithely 2000 type digital multimeter in the resistance measurement mode.
When the electrodes obtained in Examples 1 to 3 were measured, the measured value was 0.1 Ω or less, and the electrodes were conductive. Therefore, the electrodes obtained in Examples 1 to 3 can function as electrodes. Recognize.

In Example 2, electrode cross sections were observed using a scanning electron microscope (SEM). The SEM image obtained is shown in FIG. In FIG. 2, the gray-colored round portions are ferrite particles, and the white portions (light gray) are copper (Cu). As shown in FIG. 2, the conductive metal copper (Cu) constituted a continuous metal matrix in the electrode. This confirms that the electrode has high conductivity. Also, the ferrite particles were dispersed in the matrix.

ADVANTAGE OF THE INVENTION According to this invention, the electrode formation material which can form an electrode by a simple method, the manufacturing method of an electrode, and an electrode can be provided.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Japanese Patent Application No. 2019-013667) filed on January 29, 2019, the contents of which are incorporated herein by reference.

REFERENCE SIGNS LIST 1 substrate 2 magnet 3 first surface 4 second surface 5 magnetic lines of force 6 metal-coated ferrite particles

Claims (9)

An electrode-forming material comprising a ferrite composite powder,
The ferrite composite powder is composed of a plurality of metal-coated ferrite particles,
The ferrite composite powder has a shape factor SF-1 of 100 to 130,
A material, wherein the metal-coated ferrite particles comprise ferrite particles and a coating layer containing a conductive metal provided on the surfaces of the ferrite particles. 2. The material of claim 1, wherein the conductive metal comprises one or more metals selected from the group consisting of silver (Ag), copper (Cu) and nickel (Ni). A material according to claim 1 or 2, wherein the coating layer has a thickness of 10-1000 nm. The material according to any one of claims 1 to 3, wherein the ferrite composite powder has a volume average particle size (D50) of 1 to 50 µm. The ferrite particles include manganese (Mn)-based ferrite, manganese-zinc (Mn--Zn)-based ferrite, nickel (Ni)-based ferrite, nickel-zinc (Ni--Zn)-based ferrite, nickel-zinc-copper (Ni--Zn -Cu) ferrite, magnesium (Mg) ferrite, magnesium-zinc (Mg-Zn) ferrite, strontium (Sr) ferrite _, barium (Ba) ferrite, manganese-magnesium (Mn-Mg) ferrite, manganese -Magnesium- Strontium (Mn-Mg-Sr) based ferrites. A deposition step of depositing the electrode forming material according to any one of claims 1 to 5 on a substrate to form a deposit, and sintering the deposit to impart conductivity to the deposit. A method of manufacturing an electrode, comprising: 7. The method of claim 6 , wherein a magnetic field is applied to the electrode-forming material during the deposition step, and the applied magnetic field aligns the metal-coated ferrite particles in the electrode-forming material to pattern the deposit. 8. The method of claim 7 , wherein the substrate is a non-magnetic sheet and the metal-coated ferrite particles are aligned during the deposition step by an applied magnetic field generated by a magnet placed under the non-magnetic sheet. An electrode comprising a sintered body of the material according to any one of claims 1 to 5,
An electrode comprising a matrix made of a conductive metal and ferrite particles dispersed in the matrix.

Images