JP4825902B2 - Manufacturing method of dust core - Google Patents

Description

  The present invention relates generally to a method for manufacturing a powder magnetic core, and more specifically to a method for manufacturing a powder magnetic core including a plurality of metal particles covered with an insulating coating.

In recent years, with the tightening of global environmental regulations, automobile manufacturers have been actively developing developments for reducing emissions of exhaust gas and reducing fuel consumption. Therefore, the conventional mechanical control mechanism of the engine is shifting to an electronic control mechanism, and accordingly, there is a demand for higher performance and miniaturization of a magnetic material which is a central part of the control mechanism. In particular, development of materials having high magnetic properties in the middle and high frequency regions has been advanced so that more precise control can be performed with low power. In order to have high magnetic properties in the middle and high frequency region, the material needs to have both high saturation magnetic flux density, high magnetic permeability, and high electrical resistivity. In general, a metal magnetic material has a high saturation magnetic flux density and a magnetic permeability, but has a low electrical resistivity (10 ⁻⁶ to 10 ⁻⁴ Ωcm), and therefore has a large eddy current loss in a medium and high frequency region. For this reason, the magnetic properties are deteriorated and it is difficult to use the single substance. In addition, since the metal oxide magnetic material has a higher electrical resistivity (1 to 10 ⁸ Ωcm) than the metal magnetic material, the eddy current loss is small in the middle and high frequency regions, and the deterioration of the magnetic characteristics is small. However, since the saturation magnetic flux density is 1/3 to 1/2 of the metal magnetic material, there is a limit to the application. In view of this situation, by combining a metal magnetic material and a metal oxide magnetic material, composite magnetism having a high saturation magnetic flux density, a high magnetic permeability, and a high electrical resistivity so as to compensate for the disadvantages of both. Materials have been proposed.

  As a composite magnetic material as described above, for example, in Japanese Patent Application Laid-Open No. 10-503807 (Patent Document 1), a plurality of composite magnetic particles in which a film of iron phosphate is formed on the surface of iron powder are combined with polyphenylene ether or polyphenylene ether. A method of forming a composite magnetic material by bonding with organic substances such as etherimide and amide type oligomers is disclosed.

Japanese National Patent Publication No. 10-503807

  When a composite magnetic material is used in an automobile engine control mechanism, not only the above-described magnetic characteristics but also the engine is at a high temperature, and thus the composite magnetic material is required to have heat resistance. The soft magnetic material has a problem that the mechanical strength at high temperature is not sufficient.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a soft magnetic material and a powder magnetic core having excellent bending strength even at high temperatures.

  A soft magnetic material according to the present invention includes a plurality of composite magnetic particles including metal magnetic particles and an insulating coating, an aromatic polyetherketone resin, a fine metal soap having an average particle size of 2.0 μm or less, and / or An inorganic lubricant having a hexagonal crystal structure is provided. The insulating coating surrounds the surface of the metal magnetic particles and includes phosphate.

  When the soft magnetic material includes an aromatic polyetherketone resin and a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure, particularly at high temperatures. It was found that the deterioration of the bending strength in the steel was suppressed. In the heat treatment step performed at a temperature of 400 ° C. or higher and lower than the thermal decomposition temperature of the insulating coating, the aromatic polyether ketone is once melted and re-solidified (crystallized) upon cooling. In this case, it is considered that the inorganic lubricant acted as a nucleating agent and promoted crystallization. In the case of metal soap, the organic fatty chain portion is decomposed and desorbed in the heat treatment step, but remains as an inorganic zinc compound such as zinc or zinc oxide, so it is considered that it could be a nucleating agent. The aromatic polyetherketone resin has a dense structure due to crystallization, and exhibits improved heat resistance and mechanical properties due to increased intermolecular force. Thereby, it is considered that the heat resistance and mechanical strength of the powder magnetic core in which the aromatic polyetherketone resin functions as a binder are also improved.

  In the soft magnetic material, the aromatic polyether ketone resin preferably has a weight average molecular weight of 10,000 or more and 100,000 or less. By setting it to 100,000 or less, the melt viscosity of the aromatic polyetherketone resin can be lowered. As a result, when the aromatic polyetherketone resin is melted during the heat treatment process, the aromatic polyetherketone resin tends to spread between the composite magnetic particles, and the metal soap residue and / or hexagonal crystal as a nucleating agent It becomes easy to incorporate the inorganic lubricant having the structure into the aromatic polyether ketone resin. As a result, the mechanical properties of the soft magnetic material can be improved. Moreover, the intensity fall of aromatic polyether ketone resin itself can be suppressed by making a weight average molecular weight 10,000 or more.

  Preferably, in the soft magnetic material, the average particle diameter of the aromatic polyether ketone resin is 10 times or more than the average particle diameter of the metal soap and / or the inorganic lubricant having a hexagonal crystal structure, and the metal It is not more than twice the average particle size of the magnetic particles. By making the average particle size 10 times or more that of metal soap and / or an inorganic lubricant having a hexagonal crystal structure, it is possible to suppress a decrease in fluidity of the metal magnetic particles, and to reduce the metal soap and / or inorganic lubricant. It is possible to suppress the hindrance to the coating on the surface of the metal particles. By setting the average particle size of the metal magnetic particles to 2 times or less, the dispersion of the aromatic polyether ketone resin between the composite magnetic particles can be maintained.

  In the soft magnetic material, preferably, the metal soap and / or the inorganic lubricant having a hexagonal crystal structure is contained in an amount of 0.001% by mass to 0.1% by mass with respect to the plurality of composite magnetic particles. By setting the content to 0.001% by mass or more, it is possible to obtain more lubricity that suppresses damage to the insulating coating from a metal soap and / or an inorganic lubricant having a hexagonal crystal structure. On the other hand, by setting the content to 0.1% by mass or less, it is possible to further prevent a decrease in magnetic flux density and strength in the soft magnetic material.

  The dust core according to the present invention is produced using the soft magnetic material described above. According to the dust core configured as described above, it is possible to obtain a dust core having excellent bending strength even at high temperatures while realizing magnetic characteristics with small iron loss.

  As described above, according to the soft magnetic material of the present invention, it is possible to obtain a dust core having excellent bending strength even at high temperatures while realizing magnetic characteristics with small iron loss.

It is a figure which shows typically the soft-magnetic material in embodiment of this invention. It is an expanded sectional view of a dust core in an embodiment of the invention. It is a flowchart which shows the manufacturing method of the powder magnetic core in embodiment of this invention in order of a process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment)
FIG. 1 is a diagram schematically showing a soft magnetic material according to an embodiment of the present invention. As shown in FIG. 1, the soft magnetic material in the present embodiment includes metal magnetic particles 10, a plurality of composite magnetic particles 30 having an insulating coating 20 surrounding the surface of the metal magnetic particles 10, and aromatic polyether ketone. A resin 40 and fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant 50 having a hexagonal crystal structure are provided. The insulating coating 20 contains a phosphate.

  FIG. 2 is an enlarged cross-sectional view of the dust core in the embodiment of the present invention. 2 is produced by subjecting the soft magnetic material of FIG. 1 to pressure molding and heat treatment. As shown in FIG. 2, in the dust core of the present embodiment, each of the plurality of composite magnetic particles 30 is joined by an aromatic polyetherketone resin 40, or the uneven engagement of the composite magnetic particles 30 is engaged. It is joined by. The insulator 60 is obtained by changing the aromatic polyetherketone resin 40, the metal soap and / or the inorganic lubricant 50 contained in the soft magnetic material during the heat treatment.

  In the soft magnetic material and the dust core of the present invention, the metal magnetic particles 10 are, for example, iron (Fe), iron (Fe) -aluminum (Al) alloy, iron (Fe) -silicon (Si) alloy, iron (Fe) -nitrogen (N) alloy, iron (Fe) -nickel (Ni) alloy, iron (Fe) -carbon (C) alloy, iron (Fe) -boron (B) alloy, iron (Fe ) -Cobalt (Co) alloy, iron (Fe) -phosphorus (P) alloy, iron (Fe) -nickel (Ni) -cobalt (Co) alloy and iron (Fe) -aluminum (Al) -silicon ( Si) based alloy or the like. The metal magnetic particles 10 may be a single metal or an alloy.

  The average particle diameter of the metal magnetic particles 10 is preferably 30 μm or more and 500 μm or less. The coercive force can be reduced by setting the average particle size of the metal magnetic particles 10 to 30 μm or more. By setting the average particle size to 500 μm or less, eddy current loss can be reduced. Moreover, it can suppress that the compressibility of mixed powder falls at the time of pressure molding. Thereby, it can prevent that the density of the molded object obtained by pressure molding does not fall, and handling becomes difficult.

  In addition, the average particle diameter of the metal magnetic particle 10 means the particle diameter of the particle in which the sum of the masses from the smaller particle diameter reaches 50% of the total mass in the particle diameter histogram, that is, 50% particle diameter.

  The insulating coating 20 functions as an insulating layer between the metal magnetic particles 10. By covering the metal magnetic particles 10 with the insulating coating 20, it is possible to increase the electrical resistivity ρ of the dust core obtained by pressure-molding this soft magnetic material. Thereby, it can suppress that an eddy current flows between the metal magnetic particles 10, and can reduce the eddy current loss of a powder magnetic core.

  The insulating coating 20 is made of phosphate. By using a metal oxide containing phosphate for the insulating coating 20, the coating layer covering the surface of the metal magnetic particles can be made thinner. This is because the magnetic flux density of the composite magnetic particle 30 can be increased and the magnetic characteristics are improved.

  As the phosphate, in addition to iron phosphate which is an iron phosphate, for example, manganese phosphate, zinc phosphate, calcium phosphate and aluminum phosphate can be used. The phosphate may be a complex metal salt of phosphoric acid such as iron phosphate doped with a small amount of aluminum. Examples of oxides that can be used include silicon oxide, titanium oxide, aluminum oxide, and zirconium oxide.

  The insulating coating 20 may be an alloy of these metals. The insulating coating 20 may be formed in one layer as shown in the figure, or may be formed in multiple layers.

  The average film thickness of the insulating coating 20 is preferably 0.005 μm or more and 20 μm or less. More preferably, the average film thickness of the insulating coating 20 is 0.05 μm or more and 0.1 μm or less. By setting the average film thickness of the insulating coating 20 to 0.005 μm or more, energization due to the tunnel effect can be suppressed. By setting the thickness to 0.05 μm or more, energization due to the tunnel effect can be effectively suppressed. On the other hand, by setting the average film thickness of the insulating coating 20 to 20 μm or less, it is possible to prevent the insulating coating 20 from being sheared during pressure molding. In addition, since the ratio of the insulating coating 20 to the soft magnetic material does not become too large, it is possible to prevent the magnetic flux density of the dust core obtained by pressing the soft magnetic material from being significantly reduced. By setting the average film thickness of the insulating coating 20 to 0.1 μm or less, it is possible to further prevent a decrease in magnetic flux density.

  As the aromatic polyetherketone resin 40, polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneketone, or the like can be used.

  In addition, it is preferable that the aromatic polyether ketone resin 40 is included in an amount of 0.01% by mass or more and 0.1% by mass or less with respect to the plurality of composite magnetic particles 30. By including 0.01% by mass or more, the bending strength of the soft magnetic material and the dust core can be improved. On the other hand, the content of 0.1% by mass or less limits the proportion of the nonmagnetic layer in the soft magnetic material and the powder magnetic core, thereby further preventing a decrease in the magnetic flux density.

  As for the metal soap having an average particle size of 2.0 μm or less and / or the inorganic lubricant 50 having a hexagonal crystal structure, the metal soap includes zinc stearate, lithium stearate, calcium stearate, lithium palmitate, Calcium palmitate, lithium oleate, calcium oleate, or the like can be used. As the inorganic lubricant having a hexagonal crystal structure, boron nitride, molybdenum disulfide, tungsten disulfide, graphite, or the like can be used.

  In addition, the fine metal soap having an average particle size of 2.0 μm or less and / or the inorganic lubricant 50 having a hexagonal crystal structure is 0.001% by mass or more and 0.1% by mass with respect to a plurality of composite magnetic particles. It is preferable that it is contained in a proportion of mass% or less. By setting the content to 0.001% by mass or more, good lubricity for suppressing damage to the insulating film can be obtained from an inorganic lubricant having a metal soap and / or a hexagonal crystal structure. By setting the content to 0.1% by mass or less, it is possible to further prevent a decrease in magnetic flux density and strength in the soft magnetic material. The average particle size of the inorganic lubricant 50 having a metal soap and / or a hexagonal crystal structure is preferably 0.8 μm or less. By setting the thickness to 0.8 μm or less, damage to the insulating coating 20 at the time of consolidation can be further reduced, so that core loss can be further reduced.

  The average particle diameter of the metal lubricant and / or the inorganic lubricant 50 having a hexagonal crystal structure is the sum of masses from the smaller particle diameter in the particle diameter histogram measured by the laser scattering diffraction method. The particle diameter of the particles reaching 50% of the total mass, that is, 50% particle diameter D.

  The average particle diameter of the soft magnetic material is preferably 5 μm or more and 200 μm or less. This is because by setting the particle size to 5 μm or more, the powder compressibility is lowered and the magnetic flux density is lowered. On the other hand, by setting the particle size to 200 μm or less, eddy current loss in the particles can be suppressed particularly when used in the range of 1 kHz to 10 kHz.

  Next, a method for manufacturing the soft magnetic material shown in FIG. 1 and the dust core shown in FIG. 2 will be described with reference to FIGS. FIG. 3 is a flowchart showing a method of manufacturing a dust core according to the embodiment of the present invention in the order of steps.

  As shown in FIG. 3, first, a step (S10) for producing the composite magnetic particle 30 is performed. Specifically, in this step (S10), the following is performed. Metal magnetic particles 10 are prepared. And the metal magnetic particle 10 is heat-processed at the temperature of 400 degreeC or more and less than 900 degreeC, for example. Then, an insulating coating 20 is formed on each surface of the metal magnetic particles 10. The insulating coating 20 can be formed, for example, by subjecting the metal magnetic particles 10 to a phosphate chemical conversion treatment. Thereby, a plurality of composite magnetic particles 30 are obtained.

  The insulating coating 20 can be formed, for example, by subjecting the metal magnetic particles 10 to a phosphate chemical conversion treatment. By the phosphate chemical conversion treatment, for example, in addition to iron phosphate containing phosphorus and iron, an insulating coating 20 made of aluminum phosphate, silicon phosphate, magnesium phosphate, calcium phosphate, yttrium phosphate, zirconium phosphate, or the like is formed. The For forming these phosphate insulating coatings, solvent spraying or sol-gel treatment using a precursor can be used. Moreover, you may form the insulating film 20 which consists of a silicon type organic compound. For the formation of this insulating film, a wet coating process using an organic solvent, a direct coating process using a mixer, or the like can be used.

  Next, the process (S20) which mixes aromatic polyetherketone resin with the some composite magnetic particle 30 is implemented. In this step (S20), the mixing method is not particularly limited. For example, mechanical alloying method, vibration ball mill, planetary ball mill, mechanofusion, coprecipitation method, chemical vapor deposition method (CVD method), physical vapor deposition method ( PVD method), plating method, sputtering method, vapor deposition method or sol-gel method can be used.

  Next, a step (S30) of adding fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant 50 having a hexagonal crystal structure is performed. In this step (S30), metal soap and / or inorganic lubricant 50 is added to composite magnetic particles 30 at a predetermined ratio and mixed using a V-type mixer, so that the soft magnetic material in the present embodiment is obtained. Finalize. The mixing method is not particularly limited.

  Through the above steps (S10 to S30), the soft magnetic material of the present embodiment shown in FIG. 1 is obtained. In addition, when manufacturing the powder magnetic core shown by FIG. 2, the following processes are further performed.

  A step (S40) of pressure-molding the obtained soft magnetic material is performed. In this step (S40), the obtained soft magnetic material is put into a mold and, for example, press-molded at a pressure of 700 MPa to 1500 MPa. Thereby, a soft magnetic material is compressed and a molded object is obtained. The atmosphere for pressure molding is preferably an inert gas atmosphere or a reduced pressure atmosphere. In this case, it can suppress that the composite magnetic particle 30 is oxidized by oxygen in air | atmosphere.

  At the time of the pressure molding, the composite magnetic particles 30 are interposed between the adjacent composite magnetic particles 30 by interposing a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant 50 having a hexagonal crystal structure. The particles 30 are prevented from strongly rubbing with each other. At this time, since the metal soap and / or the inorganic lubricant 50 exhibits excellent lubricity, the insulating coating 20 provided on the outer surface of the composite magnetic particle 30 is not destroyed. Thereby, the form in which the insulating coating 20 covers the surface of the metal magnetic particles 10 can be maintained, and the insulating coating 20 can function reliably as an insulating layer between the metal magnetic particles 10.

  Next, a heat treatment step (S50) is performed. In this step (S50), the molded body obtained by pressure molding is subjected to heat treatment at a temperature of 400 ° C. or higher and lower than the thermal decomposition temperature of the insulating coating 20. Thereby, the distortion and dislocation existing in the molded body are removed. At this time, since the heat treatment is performed at a temperature lower than the thermal decomposition temperature of the insulating coating 20, the insulating coating 20 is not deteriorated by this heat treatment. In addition, by the heat treatment, the aromatic polyetherketone resin 40 and the fine metal soap having an average particle size of 2.0 μm or less and / or the inorganic lubricant 50 having a hexagonal crystal structure become the insulator 60.

  After the heat treatment, the powder compact shown in FIG. 2 is completed by subjecting the molded body to appropriate processing such as extrusion and cutting.

  The dust core shown in FIG. 2 produced by the above steps (S10 to S50) preferably has a filling rate of 95% or more. The filling rate of the powder magnetic core is as follows: insulating coating 20, aromatic polyetherketone resin 40, fine metal soap having an average particle size of 2.0 μm or less and / or inorganic lubricant 50 having a hexagonal crystal structure, and The measured density of the dust core measured including the voids between the composite magnetic particles 30 is obtained by dividing the measured density by the theoretical density of the metal magnetic particles 10. The theoretical density of the metal magnetic particles 10 includes an insulating coating 20, an aromatic polyetherketone resin 40, fine metal soap having an average particle size of 2.0 μm or less, and / or an inorganic lubricant having a hexagonal crystal structure. Although 50 is not taken into consideration, since the ratio of these to the whole is very small, a value approximating the actual filling rate can be obtained by the above-described method. When the metal magnetic particles 10 are made of an alloy, for example, assuming that the metal magnetic particles 10 are made of an iron-cobalt alloy, the theoretical density of the metal magnetic particles 10 is (theoretical density of iron × metal magnetism). The volume ratio of iron in the particles 10) + (theoretical density of cobalt × the volume ratio of cobalt in the metal magnetic particles 10).

  As described above, according to the soft magnetic material in the embodiment of the present invention, a plurality of composite magnets including the metal magnetic particle 10 and the insulating coating 20 that surrounds the surface of the metal magnetic particle 10 and contains phosphate. Particles 30, an aromatic polyetherketone resin 40, and an inorganic lubricant 50 having a fine particle metal soap having an average particle diameter of 2.0 μm or less and / or a hexagonal crystal structure. By providing the aromatic polyetherketone resin 40 as the binding resin, the soft magnetic material can improve the mechanical properties when heat treatment is performed.

  In addition, since the inorganic lubricant 50 having a fine particle metal soap having an average particle diameter of 2.0 μm or less and / or a hexagonal crystal structure having excellent lubricity is provided, the inorganic lubricant is deteriorated by heat treatment. Or softening can be prevented. Therefore, eddy current loss is sufficiently reduced, so that deterioration of core loss can be prevented.

According to the dust core in the embodiment of the present invention, it is pressure-molded using a soft magnetic material. Therefore, when a magnetic field of 12000 A / m or more is applied, the magnetic flux density is 16 kG or more, the electrical resistivity is 10 ⁻³ Ωcm or more and 10 ² Ωcm or less, the excitation magnetic flux density is 2.5 kG, and the measurement frequency is 5 kHz. It is possible to realize a powder magnetic core having excellent characteristics, in which a core loss value when a full loop (BH curve) is drawn is 1500 kW / m ³ or less and a bending strength at 200 ° C. is 100 MPa or more. . In addition, bending strength (bending strength) is a value measured based on the metal material common test method of JIS (Japanese Industrial Standards) Z2238.

  In this example, the effects of the soft magnetic material and the dust core according to the present invention were examined. First, with reference to Table 1 and Table 2 below, each of the dust cores of Invention Examples 1 to 12 and Comparative Examples 1 to 5 was produced by the following method.

(Preparation of dust core in Example 1 of the present invention)
Pure iron powder (trade name “ABC100.30” manufactured by Höganäs Japan Ltd., average particle diameter of 100 μm) as metal magnetic particles was prepared. And the bonder process was implemented about the surface of the said powder, and the insulating film which consists of an iron phosphate with an average film thickness of 100 nm was formed. Then, 0.05% by mass of PEEK (manufactured by Victrex MC Ltd., average particle size of 100 μm, weight average molecular weight of 43,000) was added as an aromatic polyether ketone resin. And, as an inorganic lubricant having a fine particle metal soap having an average particle size of 2.0 μm or less and / or a hexagonal crystal structure, zinc stearate having an average particle size of 0.8 μm (manufactured by NOF Corporation, 0.005% by mass of an average particle size of 0.8 μm) was added. And these were mixed for 1 hour using the V-type mixer, and the soft-magnetic material in this invention example 1 was prepared. Thereafter, a pressure of 1275 MPa was applied to the soft magnetic material to produce a molded body. And the molded object was heat-processed at 420 degreeC in nitrogen stream atmosphere for 1 hour. Thus, a dust core was produced.

(Preparation of a dust core in Invention Example 2)
Basically the same as Example 1 of the present invention, but Example 2 of the present invention is a hexagonal metal soap and / or an inorganic lubricant having a hexagonal crystal structure with an average particle size of 2.0 μm or less. It differs only in the point which used the crystal system boron nitride (hBN, the product made from a Mizushima alloy iron company, average particle diameter of 2 micrometers).

(Preparation of a dust core in Invention Example 3)
Basically the same as Example 1 of the present invention, but Example 3 of the present invention is a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in that molybdenum sulfide (MoS ₂ , manufactured by Sumiko Lubricant Co., Ltd., average particle size 1 μm) was used.

(Preparation of dust core in Invention Example 4)
Basically the same as Example 1 of the present invention, but Example 4 of the present invention is a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in the point using (graphite).

(Preparation of a dust core in Invention Example 5)
Basically the same as Example 1 of the present invention, but Example 5 of the present invention is a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in the point which added 001 mass%.

(Preparation of dust core in Invention Example 6)
Basically the same as Example 1 of the present invention, but Example 6 of the present invention is a fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in the point which added 050 mass%.

(Preparation of dust core in Invention Example 7)
Basically the same as Example 1 of the present invention, but Example 7 of the present invention is only in that PEEK (manufactured by Victrex MC Ltd.) having a weight average molecular weight of 109000 was used as the aromatic polyether ketone resin. Different.

(Preparation of dust core in Invention Example 8)
Although it is basically the same as Example 1 of the present invention, Example 8 of the present invention is based on the use of PEEK (manufactured by Victorex MC Corporation) having an average particle size of 300 μm as the aromatic polyetherketone resin. Only different.

(Preparation of dust core in Invention Example 9)
This is basically the same as Example 1 of the present invention, but Example 9 of the present invention is different only in that PEEK having a weight average molecular weight of 10,000 is used.

(Preparation of dust core in Invention Example 10)
This is basically the same as Example 1 of the present invention, but Example 10 of the present invention differs only in that PEEK having a weight average molecular weight of 100,000 is used.

(Preparation of dust core in Invention Example 11)
Basically the same as Example 1 of the present invention, but Example 11 of the present invention is PEEK which is 10 times or more the average particle size of the inorganic lubricant and twice the average particle size of the metal magnetic particles. It differs only in the point using.

(Production of dust core in Invention Example 12)
This is basically the same as Example 1 of the present invention, but Example 12 of the present invention is different only in that an inorganic lubricant contained in an amount of 0.1% by mass is used for a plurality of composite magnetic particles.

(Preparation of a dust core in Comparative Example 1)
Basically the same as Example 1 of the present invention, but Comparative Example 1 is different only in that polyphenylene sulfide (PPS, manufactured by Idemitsu Petrochemical Co., Ltd.) is used instead of the aromatic polyether ketone resin.

(Preparation of dust core in Comparative Example 2)
Basically the same as Example 1 of the present invention, but Comparative Example 2 used polyetherimide (PEI, manufactured by GE Plastics), which is an amorphous resin, instead of the aromatic polyetherketone resin. It differs only in respect.

(Preparation of a dust core in Comparative Example 3)
Basically the same as Example 1 of the present invention, but in Comparative Example 3, the average particle size is 2.0 μm or less in the form of fine metal soap and / or an inorganic lubricant having a hexagonal crystal structure. The only difference is that zinc stearate having a particle size of 7.5 μm (Nippon Yushi Co., Ltd.) was used.

(Preparation of dust core in Comparative Example 4)
Basically, it is the same as Example 1 of the present invention, but Comparative Example 4 uses ethylene instead of fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in the point which used bis stearic acid amide (Nippon Yushi Co., Ltd. product).

(Preparation of dust core in Comparative Example 5)
Basically the same as Example 1 of the present invention, but Comparative Example 5 does not add fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. It differs only in the point.

(Measurement of core loss)
About each of said powder magnetic core, about the ring-shaped molded object (heat-treated) with an outer diameter of 34 mm, an inner diameter of 20 mm, and a thickness of 5 mm, the winding of primary 300 volume and secondary 20 volume was given, and it was set as the sample for a magnetic characteristic measurement. . In these samples, iron loss was measured using a BH curve tracer (trade name “BHS-40S10K” manufactured by Riken Denshi Co., Ltd.). Specifically, first, the magnetic flux density when a 12000 A / m magnetic field was applied was measured. Then, the core loss was measured when a full loop (BH curve) was drawn at an excitation magnetic flux density of 2.5 kG (= 0.25 T (tesla)) and a measurement frequency of 5 kHz. The measurement result is a core loss value (W / m ³ ) per unit volume, and Table 2 shows the measurement result.

(Measurement of bending strength)
A test piece for a three-point bending strength test having a size of 10 mm × 10 mm × 55 mm was manufactured. Using a test piece for a three-point bending strength test, a three-point bending strength test was performed with a universal material testing machine Autograph (trade name “TG-25” manufactured by Shimadzu Corporation). The point bending strength test was performed by supporting a test piece with a span of 40 mm under normal temperature and 200 ° C. Table 3 shows the measurement results.

  As shown in Table 3, Invention Example 1 comprising an aromatic polyether ketone resin, at least one of fine metal soap having an average particle diameter of 2.0 μm or less and an inorganic lubricant having a hexagonal crystal structure The dust cores at ˜12 maintained a low core loss and exhibited a high bending strength. In particular, the weight average molecular weight of the aromatic polyether ketone resin is 10,000 or more and 100,000 or less, and the average particle diameter of the aromatic polyether ketone resin is a metal soap and / or a hexagonal crystal structure. And an inorganic lubricant having a metal soap and / or hexagonal crystal structure is more than 10 times the average particle size of the metal magnetic particles and less than twice the average particle size of the metal magnetic particles. Of Invention Examples 1 to 6 and 9 to 12 included in 0.001% by mass to 0.1% by mass with respect to the particles, Invention Examples 1 to 6 and 9 to 11 are 200 ° C. A very good bending strength was exhibited at a high temperature, and Example 12 of the present invention showed a very low core loss.

  On the other hand, the dust cores in Comparative Example 1 using PPS instead of aromatic polyetherketone resin and Comparative Example 2 using PEI were able to prevent deterioration of core loss, but the bending strength at room temperature and 200 ° C. Was low.

  In addition, a metal soap having an average particle size of 7.5 μm (manufactured by Nippon Oil & Fats Co., Ltd.) is used instead of fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure. In the dust core in Comparative Example 3 using the core core, the core loss deteriorated and the bending strength at room temperature and 200 ° C. was low.

  In addition, the dust core in Comparative Example 4 using ethylenebisstearic acid amide instead of the fine metal soap having an average particle size of 2.0 μm or less and / or an inorganic lubricant having a hexagonal crystal structure, The bending strength at room temperature and 200 ° C. was remarkably low.

  Further, the core loss of the dust core in Comparative Example 5 in which the fine metal soap having an average particle size of 2.0 μm or less and / or the inorganic lubricant having a hexagonal crystal structure was not added was significantly deteriorated.

  As described above, according to Example 1, at least one of the aromatic polyetherketone resin, the fine metal soap having an average particle size of 2.0 μm or less, and the inorganic lubricant having a hexagonal crystal structure is used. It was found that the bending strength was improved without increasing the core loss.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  The soft magnetic material and the dust core of the present invention are generally used in, for example, automobile engine peripheral devices, motor cores, electromagnetic valves, reactors, or electromagnetic components.

  DESCRIPTION OF SYMBOLS 10 Metal magnetic particle, 20 Insulating film, 30 Composite magnetic particle, 40 Aromatic polyether ketone resin, 50 Fine metal soap with an average particle diameter of 2.0 micrometers or less, and / or an inorganic lubricant which has a hexagonal crystal structure , 60 insulator.

Claims (1)

Preparing a plurality of composite magnetic particles including metal magnetic particles made of pure iron, surrounding the surface of the metal magnetic particles, and an insulating coating containing a phosphate;
Inorganic having an average particle size of 2.0 μm or less and fine metal soap and / or hexagonal crystal structure of 0.001% by mass to 0.005% by mass with respect to the composite magnetic particles Preparing a lubricant;
The weight average molecular weight is 10,000 or more and 100,000 or less, the average particle diameter of the metal soap and / or the inorganic lubricant having a hexagonal crystal structure is 10 times or more, and the average of the metal magnetic particles Preparing an aromatic polyetherketone resin having an average particle size that is no more than twice the particle size;
A step of obtaining a soft magnetic material by mixing the plurality of composite magnetic particles and the aromatic polyetherketone resin, and further adding the metal soap and / or an inorganic lubricant having a hexagonal crystal structure;
Pressure-molding the soft magnetic material to obtain a molded body;
A method for producing a powder magnetic core, comprising a step of heat-treating the molded body.

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