TW201518342A - Insulator-coated powder for magnetic member - Google Patents

Abstract

Provided is an insulator-coated flat powder (2) that is for a magnetic member such as an electromagnetic wave absorber that is effective in blocking or absorbing electromagnetic waves in a frequency range of 1 MHz-50 GHz. The insulator-coated flat powder (2) is provided with flattened metal particles (4) and an insulating film (6) that is attached to the surface of the metal particles (4). The aspect ratio of the metal particles (4) is 10-300. The film (6) is a polymer that contains a titanium alkoxide. It is preferable that the ratio of the thickness of the film (6) to the thickness of the metal particles (4) in the powder (2) be 0.002-0.2. It is preferable that the titanium alkoxide in the powder (2) be an oligomer of a titanium alkoxide. It is preferable that the coverage rate of the metal particles (4) by the film (6) in the powder (2) be 20% or higher. It is preferable that the thickness of the film (6) in the powder (2) be 1 nm to 200 nm, and that the film (6) be an oxide of titanium.

Description

Insulating coating powder for magnetic members

The present invention relates to an insulating coated powder for a magnetic member. More specifically, it relates to an insulating coated flat powder for manufacturing a magnetic member for shielding or absorbing electromagnetic waves in a frequency region of 1 MHz to 50 GHz.

Portable electronic devices such as mobile phones, notebook computers, and tablets have become popular. Recently, with the miniaturization and high performance, the components in the circuit are easily affected by components such as semiconductor components that cause noise. In addition, it has been reported that electromagnetic waves emitted by portable electronic devices have an adverse effect on the body.

In order to block electromagnetic waves emitted from a semiconductor element or a portable electronic device in a circuit board and to prevent the influence of the electromagnetic wave, a source of electromagnetic waves embedded in a magnetic member that shields or absorbs electromagnetic waves is generated. As the magnetic member, it is advantageous to use a soft magnetic metal powder in an insulating material such as a resin or a rubber to form a sheet or a ring. The magnetic member also has a soft magnetic metal powder which is treated by an insulating coating. The magnetic members include an electromagnetic wave absorber, an electromagnetic wave absorbing sheet, and a magnetic sheet.

The frequency of electromagnetic waves emitted by portable electronic devices is high. Frequency tendencies. The actual condition of the magnetic component of the past type is that electromagnetic waves in a high frequency region cannot be sufficiently shielded or absorbed. Therefore, various reviews have been made for magnetic members that effectively shield and absorb electromagnetic waves.

For example, an electromagnetic wave absorber processed into a sheet shape is disclosed in Patent Document 1 (JP-A-2002-305395). The electromagnetic wave absorber comprises a powder obtained by treating a surface of a sheet-like soft magnetic metal powder with a phosphate.

Further, an electromagnetic wave absorber is disclosed in Patent Document 2 (JP-A-2006-203233). The electromagnetic wave absorption system is composed of a soft magnetic composite filled with metal soft magnetic particles, and the metal soft magnetic particles have an electrically insulating layer made of a molecule having an organic group.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-305395

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-203233

The electromagnetic wave absorption system described in Patent Document 1 is a soft magnetic metal flake powder and an aqueous solution or an aqueous dispersion containing A) phosphoric acid, B) one or more selected from the group consisting of MgO, CaO, and ZnO, and C) boric acid. After mixing, the powder is dehydrated and dried to form a phosphate film on the surface of the powder. In order to form a film by immersing the powder in an aqueous solution (or an aqueous dispersion) containing phosphoric acid, and using a sheet powder having a small thickness, Depending on the conditions, in the phosphate treatment, there is a tendency to dissolve the powder.

The radio wave absorber described in Patent Document 2 has been reviewed for use in a UHF band of 470 MHz to 770 MHz using metal soft magnetic particles having an electrically insulating layer made of a decane-based coupling agent. In the electromagnetic wave absorber, the insulation resistance in the frequency region of 770 MHz to 50 GHz is insufficient, and the magnetic permeability is lowered to deteriorate the absorption characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulating coated flat powder for a magnetic member such as an electromagnetic wave absorber which is effective for shielding or absorbing electromagnetic waves in a frequency region of 1 MHz to 50 GHz.

According to the same aspect of the present invention, there is provided an insulating coated flat powder for a magnetic member, comprising a flat-processed metal powder and an insulating film attached to a surface of the metal powder, wherein the metal powder has an aspect ratio of 10 or more Further, 300 or less, the film is made of a polymer containing a titanium alkoxide. Here, the ratio of the thickness of the film to the thickness of the metal powder is preferably 0.002 or more and 0.2 or less. Further, the above-mentioned alkoxytitanium oxide is preferably an oligomer of a titanium alkoxide. Further, the coverage of the metal powder coated with the above film is preferably 20% or more. Further, the film thickness is preferably 1 nm or more and 200 nm or less, and the film is preferably made of an oxide of titanium.

According to a preferred embodiment of the present invention, the film is formed from a polymer containing alkoxides and alkoxides. That is, according to the preferred aspect, there is provided an insulating coated flat powder for a magnetic member, which is provided with a flat processed metal powder and attached to a surface of the metal powder. In the insulating film, the aspect ratio of the metal powder is 10 or more and 300 or less, and the film is made of a polymer containing alkoxides and alkoxides. Here, the ratio of the mass of titanium contained in the film to the mass of ruthenium is preferably 2 or more and 6 or less. Further, the above-mentioned alkoxytitanium oxide is preferably an oligomer of a titanium alkoxide. Further, the metal powder coating ratio coated by the film is preferably 20% or more. Further, the film thickness is preferably 1 nm or more and 200 nm or less, and the film is preferably made of an oxide of titanium or lanthanum.

According to another aspect of the present invention, there is provided a magnetic member formed by using the above-described insulating coated flat powder of the present invention.

In the magnetic member of the present invention, the flat powder is coated with an insulating film to cover the flat-processed metal powder. This film is made of a polymer containing alkoxides and, if necessary, alkoxylated oximes. Since the mixture of the titanium alkoxides, or the alkoxytitaniums and the alkoxylated oximes is polymerized at an appropriate reaction rate, an insulating film having a small number of cracks and a small thickness can be formed.

The index indicating the performance of the magnetic member is the permeability μ, the real permeability μ′, and the imaginary permeability μ′. The real permeability μ′ indicates the characteristics of the electromagnetic shielding characteristics. The imaginary permeability μ′ indicates the electromagnetic absorption characteristic. Good or bad. Further, the magnetic permeability μ is expressed by the following equation using the real magnetic permeability μ′ and the imaginary magnetic permeability μ′. In the formula, “j” is an imaginary number ((j) ² =−1). μ = μ' + jμ", and in the present application, each of the magnetic permeability μ, the real magnetic permeability μ', and the imaginary magnetic permeability μ" is expressed as a specific permeability with respect to the ratio of vacuum permeability.

The metal-based magnetic material has a characteristic that the skin depth (a scale at which the eddy current can flow) is shallow, and the magnetic permeability does not decrease in the high-frequency region exceeding the limit of Snoek, and can be exhibited in a higher frequency region. The characteristics of the middle. It is further characterized by flat processing. In addition, the metal powder is more likely to exhibit a high saturation magnetic flux density than the ferrite iron. However, since the metal powder is electrically conductive, the apparent thickness of the flat powder is increased when it is brought into contact with each other (in a portion corresponding to the total thickness of the flat powder to be contacted). When the apparent thickness of the flat powder is increased, the loss of the eddy current is increased to decrease the real permeability μ'. Moreover, the imaginary part permeability μ′ seen in the high-frequency region is also lower than the real part permeability μ′. The powder of the present invention is formed by mixing the powder with the resin or the rubber because the insulating film is formed on the surface of the metal powder. The magnetic member is obtained by the like, and the film can prevent the metal powder from coming into contact with each other. Accordingly, the decrease in the real magnetic permeability μ' due to the occurrence of the eddy current is suppressed. According to the powder of the present invention, the phase Compared with the conventional powder, the real magnetic permeability μ' of the magnetic member can be improved. Further, the reduction of the imaginary magnetic permeability μ" seen in the high-frequency region is also suppressed. Therefore, the magnetic member including the powder of the present invention is also excellent in electromagnetic wave absorption characteristics in a high frequency region. According to the powder of the present invention, a magnetic member excellent in both electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics is obtained.

2‧‧‧Insulated coated flat powder

4‧‧‧Metal powder

6‧‧ ‧ film

Fig. 1 is a cross-sectional view showing an insulating coated flat powder for a magnetic member according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings.

Fig. 1 is a cross-sectional view showing the insulating coated flat powder 2 of the present invention. The magnetic member such as an electromagnetic wave absorber, an electromagnetic wave absorbing sheet, and a magnetic sheet is formed using the powder 2. In the production of the magnetic member, a base material powder composed of a myriad of powders 2 is prepared. The substrate powder is mixed in a resin or a rubber to obtain a composition. Using this composition, a magnetic member was formed. The shape of the formed magnetic member is not particularly limited. The shape is exemplified by a sheet shape, a ring shape, a cubic shape, a rectangular parallelepiped shape, and a cylindrical shape. Further, the method of mixing the base material powder with the resin or the rubber is not limited. This mixing method employs a conventional method. The method for forming the composition into a magnetic member is also not limited. The forming method is also a method known in the past. From the viewpoint of easy processing, a processing aid such as a lubricating material or a binder may be blended in the composition.

The powder 2 is provided with a metal powder 4 and a film 6. This powder 2 is composed of the metal powder 4 and the film 6. The film 6 is attached to the surface of the metal powder 4. The powder 2 may also be provided with a film different from the film 6 on the surface of the film 6. A film different from the film 6 may be provided between the metal powder 4 and the film 6.

The metal powder 4 is, for example, a medium agitating type pulverizer (attritor) A metal particle obtained by a gas atomization method or a water atomization method and pulverized by a flat processor. Metal particles obtained by a mechanical process such as pulverization may be subjected to flat processing and used as the metal powder 4. The metal particles obtained by a chemical process such as reduction of an oxide may be subjected to flat processing and used as the metal powder 4. Further, as the metal powder 4, a powder which is subjected to pulverization and flat processing and then subjected to deformation and burntness may be used.

The metal powder 4 as described above is subjected to flat processing. The flatness of the metal powder 4 is expressed in terms of aspect ratio. In the present application, the aspect ratio is expressed by the ratio of the length of the long axis of the metal powder 4 to the thickness of the metal powder 4. When the aspect ratio is large, the influence of the demagnetizing factor is suppressed. A large aspect ratio affects the real permeability μ'.

In the powder 2, the aspect ratio of the metal powder 4 is 10 or more and 300 or less. Thereby, the real magnetic permeability μ' in the high frequency region can be greatly improved. When the aspect ratio is less than 10, the real magnetic permeability μ' in the high-frequency region is lowered, and the electromagnetic wave shielding characteristics are deteriorated. Based on this viewpoint, the length and width are preferably 50 or more, more preferably 60 or more, and still more preferably 80 or more. Further, when the aspect ratio exceeds 300, when the powder 2 is mixed with a resin or a rubber or the like, the powder 2 is broken. When the powder 2 is broken, the aspect ratio is lowered, and it is difficult to process it while maintaining the characteristics. Based on this viewpoint, the length and width are preferably 200 or less, more preferably 150 or less, and still more preferably 100 or less.

In the present application, the aspect ratio of the metal powder 4 is obtained as follows. The metal powder 4 was observed using a scanning electron microscope (SEM), and the position where the length was the largest in plan view was specified. Using this position as the long axis, the length L of the long axis is measured. For 50 metal powders 4, measuring For the length L, the sum average value Lav of these is calculated. This average value Lav is used as the length of the long axis of the metal powder 4 for calculating the aspect ratio. This metal powder 4 was embedded in a resin and polished, and the polished surface was observed with an optical microscope. The thickness direction of the metal powder 4 is specified, and the maximum thickness tm and the minimum thickness tn are measured, and the average value of the maximum thickness tm and the minimum thickness tn ((tm+tn)/2) is calculated. For 50 metal powders 4, an average value ((tm+tn)/2) was obtained, and the sum average value tav of these was calculated. The average value tav is used as the thickness of the metal powder 4 for calculating the aspect ratio. The aspect ratio (Lav/tav) of the metal powder 4 is obtained by dividing the length Lav of the long axis by the thickness tav.

In the metal powder 2, the metal powder 4 is a soft magnetic material. As the metal powder 4, a pure metal containing no other component, an alloy powder made of an alloy steel obtained by adding an alloy component in advance, and a partially diffused and adhered alloy component to a surface of a pure metal or alloy powder can be used. Pure metals are exemplified by iron (Fe), nickel (Ni), cobalt (Co), and cadmium (Gd). The alloy powder is exemplified by adding boron (B), aluminum (Al), bismuth (Si), bismuth (Ge), titanium to those in which the above pure metals are alloyed with each other, or in which the above-mentioned pure metal or pure metal is alloyed with each other. (Ti), vanadium (V), chromium (Cr), manganese (Mn), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo) and tungsten (W) At least one of the group selected.

The metal powder 4 is specifically exemplified as pure iron powder containing no other components, Fe-3mass% Si powder, Fe-6.5 mass% Si powder, Fe-3mass%Si-2mass%Cr powder, Fe-5mass%Al powder, Fe. - 9.5 mass% Si-5.5 mass% Al (sendust) powder, Fe-50 mass% Co (permendur) and Fe-50 mass% Ni (permalloy). Also, "mass%" is synonymous with mass%.

The film 6 is insulative. This powder 2 is formed on the surface of the metal powder 4 to form an insulating film 6. In the magnetic member obtained by mixing the powder 2 with an insulator such as a resin or a rubber, the film 6 can prevent the metal powders 4 from coming into contact with each other. Thereby, the decrease in the real magnetic permeability μ' due to the occurrence of the eddy current is suppressed. According to the powder 2, the real magnetic permeability μ' of the magnetic member can be improved as compared with the conventional powder. Since the powder 2 contributes to the magnetic flux concentration effect of the magnetic member, the magnetic member using the powder 2 is excellent in electromagnetic wave shielding characteristics. Further, the magnetic permeability of the imaginary part can be suppressed. Therefore, the magnetic member including the powder 2 of the present invention is excellent in electromagnetic wave absorption characteristics in a high frequency region. According to the powder 2 of the present invention, electromagnetic wave shielding characteristics and electromagnetic waves can be obtained. A magnetic member excellent in absorption characteristics.

As shown, the film 6 is coated with the metal powder 4. The film 2 of the powder 2 is laminated on the metal powder 4. The film 6 is joined to the metal powder 4. The film 6 is coated with the entire metal powder 4 or a part of the metal powder 4. From the viewpoint of electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics, it is preferred that the entire metal powder 4 is covered with the film 6. The film 6 may be composed of two or more layers.

The film 6 is made of a polymer containing a titanium alkoxide. In detail, the film 6 is made of a polymer of an alkoxide type. this In the invention, the titanium alkoxide is a compound in which at least one alkoxide group is bonded to a titanium atom in one molecule. Further, in the present invention, a compound in which an alkoxide-based organic group is bonded to a negatively charged oxygen. The organic group is based on an organic compound. The concept of the titanium alkoxide includes a monomer of a titanium alkoxide, an oligomer formed by polymerizing the monomer, and a compound (hereinafter also referred to as a precursor) before the formation of the titanium alkoxide. Further, the film 6 may be composed of a polymer further containing a component other than the alkoxide.

The ratio of the thickness of the film 6 made of the titanium alkoxide to the thickness of the flat-processed metal powder 4 is preferably 0.002 or more and 0.2 or less, from the viewpoint of obtaining a magnetic member having excellent electromagnetic shielding properties and electromagnetic wave absorption characteristics. More preferably, it is 0.005 or more and 0.15 or less, More preferably, it is 0.01 or more and 0.1 or less. When the ratio is 0.002 or more, the insulation resistance and the magnetic permeability are improved, or the apparent thickness of the metal powder 4 is increased (the operation of the metal powder 4 in an apparent contact with each other), so that the influence of the demagnetization coefficient is suppressed and the effect is increased. Permeability. Moreover, when the ratio is 0.2 or less, the film 6 is thinned, the filling amount of the powder 2 is increased, and the magnetic permeability is improved. Further, the thickness of the film 6 is a thickness T of a thick thickness, and the thickness of the metal powder 4 is the aforementioned thickness tav.

The film 6 may also be formed of a polymer containing alkoxides and alkoxides. In other words, the film 6 may be a polymer of a mixture of alkoxides and alkoxides. In the present invention, the alkoxylated oxime is a compound in which at least one alkoxide group is bonded to a ruthenium atom in one molecule. The concept of alkoxylated oxime contains alkylene oxide monomer, complex A plurality of oligomers formed by polymerization of the monomer and a compound (hereinafter also referred to as a precursor) at a stage before the formation of alkoxide. Further, the film 6 may be composed of a polymer containing a mixture of alkoxides and alkoxides and further containing a mixture of other components.

Specific examples of the titanium alkoxide are tetramethyltitanium oxide, titanium tetraethoxide, titanium tetraisopropoxide, titanium tetrabutoxide, tetra-2-ethylhexyltitanium oxide, and isopropyltri-dodecylbenzenesulfonate. Mercapto titanate.

Specific examples of the alkoxylated hafnium are tetraethoxydecane, tetramethoxydecane, methyltriethoxydecane, tetraisopropoxydecane, vinyltrimethoxydecane, γ-aminopropyltriethyl Oxydecane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxydecane.

The powder 2 described above can be produced by various coating methods. The coating method is exemplified by a mixing method, a sol-gel method, a spray drying method, and a rotating fluidized bed method.

The titanium alkoxides and alkylene oxides used in the present invention can be used in a solvent dilution. The solvent is not particularly limited as long as it can dissolve or disperse the titanium alkoxide or the alkoxylated molybdenum. The solvent is exemplified by, for example, acetone, methyl ethyl ketone, acetonitrile, methanol, ethanol, isopropanol, n-butanol, benzene, toluene, hexane, heptane, cyclohexane, chloroform, chlorobenzene, dichlorobenzene, Ethyl acetate, ethyl propionate and tetrahydrofuran.

In the powder 2, the film 6 is formed by using a mixture of an alkoxide or a titanium alkoxide and an alkoxide. The alkoxide oxide can be polymerized on the surface of the metal powder 4 at an appropriate reaction rate as compared with an alkoxide monomer such as an alkagnelate or an alkoxide. In addition, alkoxides The mixture of the alkoxylated oximes can be polymerized on the surface of the metal powder 4 at an appropriate reaction rate as compared with the alkoxide monomers such as alkoxides, alkoxides, alkoxides or zirconium oxides. When the film 6 is made of a polymer of an alkoxide type, the film 6 is made of an oxide of titanium. When the film 6 is made of a polymer of a mixture of an alkoxide and an alkoxylated cerium, the film 6 is made of an oxide of titanium and cerium. The film 6 formed of a titanium alkoxide or a mixture containing a titanium alkoxide and an alkoxide is less cracked. Moreover, the film 6 is thin. This film 6 contributes to an improvement in electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics of the magnetic member formed of the powder 2. According to the present invention, a magnetic member excellent in electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics is obtained.

When an oligomer of a titanium alkoxide is used as the titanium alkoxide in the formation of the film 6, the alkoxide is used as the alkoxide, as compared with the case of using a titanium alkoxide in the formation of the film 6. It can be polymerized at a more appropriate reaction rate. Therefore, not only the occurrence of cracking of the film 6 but also a thinner film 6 can be obtained more effectively. This film 6 contributes to an improvement in electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics of the magnetic member. Therefore, in the present invention, an alkoxytitanium oxide is preferably an oligomer of a titanium alkoxide, from the viewpoint of an appropriate reaction rate and improvement in characteristics.

The oligomer of titanium alkoxide is obtained by polymerizing a monomer of a plurality of titanium alkoxides. In other words, the oligomer of the titanium alkoxide is formed from a monomer of the titanium alkoxide. The amount of the oligomer-forming monomer affects the reaction rate of the alkoxytitanium when the film 6 is formed. From the viewpoint of an appropriate reaction rate, the number of monomers forming the alkoxytitanium oxide oligomer is preferably 4 It is preferably 50 or less.

In the powder 2, the coverage C of the metal powder 4 coated by the film 6 is preferably 20% or more. As described above, the film 6 contributes to electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics of the magnetic member formed using the powder 2. From the viewpoint of improving the characteristics, the coverage C of the metal powder 4 coated by the film 6 is more preferably 30% or more. More preferably, the coverage C is 50% or more. It is preferable that the entire metal powder 4 is coated with the film 6, so that the coverage C is preferably 100%. In the powder 2 shown in Fig. 1, the coverage of the metal powder 4 coated with the film 6 was 100%. This film 6 is coated with the entire metal powder 4.

In the present application, the coverage C of the metal powder 4 coated by the film 6 is calculated by using a cross-sectional image of the powder 2 taken by a transmission electron microscope (TEM). In detail, in the countless powder 2 observed by TEM, 10 fields of view were taken in a state where the boundary between the metal powder 4 and the film 6 was confirmed. In the photograph taken, the length of the metal powder 4 covered by the film 6 (hereinafter also referred to as the length of the coating) and the length of the surface of the metal powder 4 were measured. In the present specification, the value indicated by the percentage of the coating length divided by the surface length of the metal powder 4 is expressed as the coverage ratio C.

In Fig. 1, two arrows T indicate the thickness of the film 6. In the present application, the thickness T is obtained by taking a cross section of the powder 2 of 10 fields of view by a transmission electron microscope (TEM), and expressing the average value of the measured values obtained from the photographed cross-sectional image. Further, at the time of photographing, the powder 2 as a sample was adjusted so that the cross section of the powder 2 was observed by a focused ion beam (FIB, Focesd Ion Beam) processing.

The thickness T of the film 6 affects the electromagnetic wave absorption characteristics and the electromagnetic wave shielding characteristics of the magnetic member formed using the powder 2. When the thickness T is 1 nm or more, the insulation resistance of the formed magnetic member is increased. In this case, the real magnetic permeability μ' is further increased, and the reduction of the imaginary magnetic permeability μ" seen on the high frequency side can be suppressed more than the real magnetic permeability μ'. From this viewpoint, the thickness T is preferably 1 nm. The above is more preferably 10 nm or more, more preferably 20 nm or more. When the thickness T is 200 nm or less, the filling ratio of the powder 2 contained in the magnetic member can be improved (the volume of the substrate powder formed by the innumerable powder 2) The ratio of the volume of the resin or the rubber in which the powder 2 is dispersed. In this case, the real magnetic permeability μ' is further increased, and the decrease in the imaginary magnetic permeability μ" is further suppressed. From this viewpoint, the thickness T is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 70 nm or less.

As described above, in the powder 2, the film 6 may be a polymer of a mixture of an alkoxide and a cerium alkoxide. Therefore, the film 6 may be made of oxides of titanium and tantalum. Since not only the alkoxide-containing titanium oxide but also the alkoxylated hafnium, it is possible to polymerize at a more appropriate reaction rate.矽 contributes to electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics. The adhesion between the metal powder 4 and the film 6 is improved by adding ruthenium. Thereby, when the powder 2 is mixed with a resin or a rubber to produce a composition, or when the magnetic member is molded from the composition, the peeling of the coating 6 from the metal powder 4 can be prevented. According to this aspect, a magnetic member excellent in electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics is obtained.

When the film 6 contains ruthenium, the ratio A of the mass of titanium contained in the film 6 to the mass of the yttrium is preferably 2 or more and 6 based on the viewpoint of obtaining a magnetic member excellent in electromagnetic shielding properties and electromagnetic wave absorption characteristics. Next, it is preferably 3.5 or more and 5.5 or less. When the ratio is 6 or less, the adhesion of the film 6 is improved. When the adhesion of the film 6 is improved, when the powder 2 is filled or mixed with the resin or the rubber, since the film 6 is prevented from being peeled off from the metal powder 4, the insulation resistance can be improved and the electromagnetic wave shielding characteristics and electromagnetic wave absorption characteristics can be further improved. From the viewpoint of forming the stable film 6, the ratio A is more preferably 5.5 or less. When the ratio A is 2 or more, the Si component contained in the film 6 is an appropriate amount, and the adhesion of the film 6 is improved. In this case, the ratio A is more preferably 3.5 or more from the viewpoint of forming the film 6 in a stable manner.

[Examples]

Hereinafter, the effects of the present invention will be described by way of examples, but the present invention should not be construed restrictively based on the description of the examples.

Examples A1 to A36 and Comparative Examples A1 to A10

Using a flat powder for a magnetic member made of a polymer containing a titanium alkoxide, the magnetic member was produced and evaluated as follows.

[Production of Magnetic Sheet (Magnetic Member)]

Prior to the production of the magnetic sheets, the powders of the respective examples shown in the following Tables 1 and 2 were prepared. In the production of the powder, a powder (10 kg) made of a myriad of metal powder was prepared. The powder was treated with a pulverizer, and each metal powder was subjected to flat processing. Further, as the metal powder, Fe-3mass% Si powder and Fe-9.5 mass% Si-5.5 mass% Al powder were used.

Use a treatment solution containing alkoxytitanium, apply flat A film was formed on the processed metal powder to prepare an insulating coated flat powder as shown in Fig. 1. The types of the titanium alkoxides used in the production are shown in Tables 1 and 2 below. The oligomer of the titanium alkoxide used for the formation of the film is prepared by adding an appropriate amount of a solvent to the monomer of the titanium alkoxide. Further, Table 1 shows the case where Fe-3mass%Si powder is used as the metal powder, and Table 2 shows the case where Fe-9.5 mass% Si-5.5 mass% Al powder is used as the metal powder.

Using a small kneader, the substrate powder and the epoxy resin obtained by insulating the coated flat powder obtained as described above were kneaded at a temperature of 100 ° C to obtain a resin composition in which the powder was uniformly dispersed. The volume ratio of the epoxy resin to the substrate powder is 5 to 2. The resin composition was heat-treated at 4 MPa and 200 ° C for 5 minutes to obtain a magnetic sheet having a thickness of 0.1 mm.

[Evaluation of Magnetic Sheets]

For the produced magnetic sheet, the real magnetic permeability μ' and the specific resistance at a temperature of 25 ° C and a frequency of 20 MHz were measured. The results are shown in Tables 1 and 2 below. Further, the measurement of the real magnetic permeability μ' was carried out by the name "Vector Network Analyzer N5245A" manufactured by Agilent Technologies. For the measurement of the specific resistance, the product name "DSM-8104" manufactured by Hioki Electric Co., Ltd. was used.

[Description of powder in each case]

Hereinafter, the powder of each example will be described in detail.

Examples A1 to A6, A11, A12, A15, A16, A19 to A24, A29, A30, A33 and A34 used metal powders having an aspect ratio falling within the range of 10 to 300. The film system is formed of a monomer of titanium alkoxide. The ratio (T/tav) of the film thickness T and the thickness T to the thickness of the metal powder tav and the coating ratio C of the metal powder coated by the film are shown in Tables 1 and 2, respectively.

Examples A7 to A10, A13, A14, A17, A18, A25 to A28, A31, A32, A35 and A36 used metal powders having an aspect ratio falling within the range of 10 to 300. The film system is formed of an oligomer of titanium alkoxide. The ratio (T/tav) of the film thickness T and the thickness T to the thickness of the metal powder tav and the coating ratio C of the metal powder coated by the film are shown in Tables 1 and 2, respectively.

Comparative Examples A1, A2, A6 and A7 used metal powders having an aspect ratio of less than 10 or more than 300. The film thickness T of each example and the metal powder coverage rate C coated by the film are shown in Tables 1 and 2.

The coating films of Comparative Examples A3 to A5 and A8 to A10 were formed of metal alkoxides other than titanium alkoxide. The film thickness T of each example and the metal powder coverage rate C coated by the film are shown in Tables 1 and 2.

[Comprehensive evaluation 1 (using magnetic sheets of Fe-3mass%Si powder)]

Based on the real magnetic permeability μ' and the value of the specific resistance, the following evaluations were made.

A: The real part permeability μ′ is 12 or more, and the specific resistance is 1.0×10 ⁵ Ω··m or more.

B: The real part permeability μ′ is 10 or more and less than 12, and the specific resistance is 1.0×10 ⁵ Ω··m or more.

C: The real part permeability μ′ is 9 or more and less than 10, or the real magnetic permeability μ′ is 10 or more but the specific resistance is less than 1.0×10 ⁵ Ω·m

D: The real part permeability μ' is less than 9

The results are shown in Table 1. The order of good is in the order of A, B, C, and D.

[Comprehensive evaluation 2 (magnetic sheet using Fe-9.5mass%Si-5.5mass%Al powder)]

Based on the real magnetic permeability μ' and the value of the specific resistance, the following evaluations were made.

A: The real part permeability μ′ is 8 or more, and the specific resistance is 1.0×10 ⁷ Ω··m or more.

B: The real part permeability μ′ is 7 or more and less than 8, and the specific resistance is 1.0×10 ⁷ Ω··m or more.

C: The real part permeability μ′ is 6 or more and less than 7, or the real magnetic permeability μ′ is 7 or more but the specific resistance is less than 1.0×10 ⁷ Ω·m

D: The real part permeability μ' is less than 6

The results are shown in Table 2. The order of good is in the order of A, B, C, and D.

As shown in Table 1, when Fe-3mass%Si powder was used as the metal powder, the real magnetic permeability μ' of 9 or more was achieved using the magnetic sheet of the powder of the example at a frequency of 20 MHz. Further, when an oligomer of a titanium alkoxide is used for forming a film, a real magnetic permeability μ' of 12 or more and a specific resistance of 1.0 × 10 ⁵ Ω··m or more are realized. As shown in Table 2, when Fe-9.5 mass% Si-5.5 mass% Al powder was used as the metal powder, the real magnetic permeability μ' of 6 or more was achieved using the magnetic sheet of the powder of the example at a frequency of 20 MHz. Further, when an oligomer of a titanium alkoxide is used for the formation of a film, a real magnetic permeability μ' of 8 or more and a specific resistance of 1.0 × 10 ⁷ Ω ‧ m or more are achieved.

Examples B1 to B32 and Comparative Examples B1 to B4

A flat powder for a magnetic member made of a polymer containing a titanium alkoxide and an alkoxylated molybdenum was used, and the magnetic member was produced and evaluated as follows.

[Production of Magnetic Sheet (Magnetic Member)]

Prior to the production of the magnetic sheets, the powders of the respective examples shown in Tables 3 and 4 below were prepared. In the production of the powder, a myriad of powder (10 kg) made of a metal powder was prepared. The powder was treated with a pulverizer, and each metal powder was subjected to flat processing. Further, as the metal powder, Fe-3mass% Si powder and Fe-9.5 mass% Si-5.5 mass% Al powder were used.

A film containing a titanium alkoxide and an alkoxylated alkoxide was used to form a film on the flattened metal powder to prepare an insulating coated flat powder as shown in Fig. 1 . The types of the titanium alkoxides and alkoxylated oximes used in the production are shown in Tables 3 and 4 below. Alkane used in the formation of a film The oligomer of titanium oxide is produced by adding an appropriate amount of a solvent to the monomer of the titanium alkoxide. Further, Table 3 shows the case where Fe-3mass%Si powder is used as the metal powder, and Table 4 shows the case where Fe-9.5 mass% Si-5.5 mass% Al powder is used as the metal powder.

Using a small kneader, the substrate powder and the epoxy resin obtained by insulating the coated flat powder obtained as described above were kneaded at a temperature of 100 ° C to obtain a resin composition in which the powder was uniformly dispersed. The volume ratio of the epoxy resin to the substrate powder is 5 to 2. The resin composition was heat-treated at 4 MPa and 200 ° C for 5 minutes to obtain a magnetic sheet having a thickness of 0.1 mm.

[Evaluation of Magnetic Sheets]

With respect to the produced magnetic sheet, the real magnetic permeability μ' and the specific resistance at a temperature of 25 ° C and a frequency of 20 MHz were measured. The results are shown in Tables 3 and 4 below. Further, the measurement of the real magnetic permeability μ' was carried out by the name "Vector Network Analyzer N5245A" manufactured by Agilent Technologies. For the measurement of the specific resistance, the product name "DSM-8104" manufactured by Hioki Electric Co., Ltd. was used.

[Description of powder for each case]

Hereinafter, the powder in each example will be described in detail.

Examples B1 to B4, B6, B8, B13, B15, B17 to B20, B22, B24, B29 and B31 used metal powders having an aspect ratio falling within the range of 10 to 300. The film system is formed of a monomer of a titanium alkoxide and a lanthanum alkoxide. The film thickness T of each example and the metal powder coverage rate C coated by the film are shown in Tables 3 and 4.

Examples B5, B7, B9 to B12, B14, B16, B21, B23, B25 to B28, B30 and B32 used metal powders having an aspect ratio falling within the range of 10 to 300. The film system is formed of an oligomer of titanium alkoxide and an alkoxylated hafnium. The film thickness T of each example and the metal powder coverage rate C coated by the film are shown in Tables 3 and 4.

Comparative Examples B1 to B4 used metal powders having an aspect ratio of less than 10 or more than 300. The film thickness T of each example and the metal powder coverage rate C coated by the film are shown in Tables 3 and 4.

[Comprehensive evaluation 1 (using magnetic sheets of Fe-3mass%Si powder)]

Based on the real magnetic permeability μ' and the value of the specific resistance, the following evaluations were made.

S: the real part permeability μ′ is 13 or more, and the specific resistance is 1.0×10 ⁶ Ω··m or more.

A: The real part permeability μ′ is 12 or more and less than 13, and the specific resistance is 1.0×10 ⁵ Ω··m or more.

B: The real part permeability μ′ is 10 or more and less than 12, and the specific resistance is 1.0×10 ⁵ Ω··m or more.

C: the real part permeability μ′ is 8 or more and less than 10, or the real magnetic permeability μ′ is 10 or more but the specific resistance is less than 1.0×10 ⁵ Ω·m

D: The real part permeability μ' is less than 8

The results are shown in Table 3. The good order is in the order of S, A, B, C, and D.

[Comprehensive evaluation 2 (magnetic sheet using Fe-9.5mass%Si-5.5mass%Al powder)]

Based on the real magnetic permeability μ' and the value of the specific resistance, the following evaluations were made.

S: The real part permeability μ′ is 10 or more, and the specific resistance is 1.0×10 ⁷ Ω··m or more.

A: The real part permeability μ′ is 8 or more and less than 10, and the specific resistance is 1.0×10 ⁷ Ω··m or more.

B: The real part permeability μ′ is 7 or more and less than 8, and the specific resistance is 1.0×10 ⁷ Ω··m or more.

C: The real part permeability μ′ is 6 or more and less than 7, or the real magnetic permeability μ′ is 7 or more but the specific resistance is less than 1.0×10 ⁷ Ω·m

D: The real part permeability μ' is less than 6

The results are shown in Table 4. The good order is in the order of S, A, B, C, and D.

As shown in Table 3, when Fe-3mass%Si powder was used as the metal powder, the real magnetic permeability μ' of 8 or more was achieved using the magnetic sheet of the powder of the example at a frequency of 20 MHz. Further, by setting the coating ratio C of the metal powder coated with the film to 20% or more and the film thickness T to be 1 nm or more and 200 nm or less, real magnetic permeability μ' of 10 or more and 1.0 × 10 ⁵ Ω can be realized. Specific resistance above m. Further, in the formation of the film, a real-time magnetic permeability μ of 13 or more is achieved by using a titanium alkoxide and a lanthanum alkoxide so that the ratio A of the titanium mass to the yttrium mass in the film is 2 or more and 6 or less. 'And a specific resistance of 1.0 × 10 ⁶ Ω ‧ m or more. As shown in Table 4, when Fe-9.5 mass% Si-5.5 mass% Al powder was used as the metal powder, the real magnetic permeability μ' of 6 or more was achieved using the magnetic sheet of the powder of the example at a frequency of 20 MHz. Further, by setting the coating ratio C of the metal powder coated with the film to 20% or more and the film thickness T to 1 nm or more and 200 nm or less, real magnetic permeability μ' of 7 or more and 1.0 × 10 ⁷ Ω·m are realized. The above specific resistance. In addition, in the formation of the film, a real-time magnetic permeability μ of 10 or more is achieved by using a titanium alkoxide and an alkoxide oxide so that the ratio A of the mass of titanium contained in the film to the mass of the yttrium is 2 or more and 6 or less. 'And a specific resistance of 1.0 × 10 ⁷ Ω ‧ m or more.

2‧‧‧Insulated coated flat powder

4‧‧‧Metal powder

6‧‧ ‧ film

Claims (11)

A magnetic member is an insulating coated flat powder comprising a flat metal powder and an insulating film adhered to the surface of the metal powder, wherein the metal powder has an aspect ratio of 10 or more and 300 or less, and the film is composed of Made of a polymer of alkoxides. The magnetic member according to claim 1 is coated with a flat powder by insulation, wherein a ratio of the thickness of the film to the thickness of the metal powder is 0.002 or more and 0.2 or less. The magnetic member according to claim 1 is coated with a flat powder in which the alkoxytitanium oxide is an oligomer of a titanium alkoxide. The magnetic member of claim 1 is coated with a flat powder by insulation, wherein a coverage of the metal powder adhered to the film is 20% or more. The magnetic member according to claim 1 is coated with a flat powder in which the thickness of the film is 1 nm or more and 200 nm or less, and the film is made of an oxide of titanium. The magnetic member according to claim 1 is coated with a flat powder of an insulating film, wherein the film is made of a polymer containing alkoxides and alkoxides. The magnetic member of claim 6 is coated with a flat powder by insulation, wherein the ratio of the mass of titanium contained in the film to the mass of ruthenium is 2 or more and 6 or less. The magnetic member according to claim 6 is coated with a flat powder of an insulating material, wherein the above-mentioned titanium alkoxide is an oligomer of a titanium alkoxide. The magnetic member according to claim 6 is coated with a flat powder by insulation, wherein a coverage of the metal powder adhered to the film is 20% or more. The magnetic member according to claim 6 is coated with a flat powder of an insulating film having a thickness of 1 nm or more and 200 nm or less, and the film is made of an oxide of titanium and lanthanum. A magnetic member formed by using an insulating member coated with a flat powder of the magnetic member according to any one of claims 1 to 10.