JP6531979B2 - Fe-based alloy composition, soft magnetic powder, composite magnetic body, and method of producing soft magnetic powder - Google Patents

Description

  The present invention relates to a soft magnetic powder used for a composite magnetic material in which soft magnetic powder is oriented and dispersed, an Fe-based alloy composition therefor, the magnetic sheet, and a method of producing the soft magnetic powder.

  In order to reduce the size of the electronic device by mounting the electronic components at a high density, interference by electromagnetic waves generated from each electronic component is a problem. A sheet-like composite magnetic body is used for the purpose of reducing radio interference (EMI) inside such electronic devices. A magnetic sheet composed of such a composite magnetic body is a resin sheet in which flat soft magnetic powder is oriented and dispersed in a matrix material composed of resin, and the imaginary magnetic permeability μ ′ ′ in a desired frequency band is increased. The magnetic loss is used to convert unnecessary electromagnetic radiation into heat and absorb it.

  In addition, flat soft magnetic powder is dispersed in resin for communication assistance applications that are integrated with a wireless communication medium such as an RFID tag and attempt to extend the communication distance via radio waves as much as possible. Similar magnetic sheets are used. In such a magnetic sheet, the electromagnetic waves received by the antenna are guided to the surrounding metal members and the like before reaching them, so that transmission from the antenna can be performed as much as possible without loss. Here, it is designed to lower the imaginary permeability μ ′ while increasing the real permeability μ ′.

  By the way, the permeability characteristic consisting of the real permeability μ ′ and the imaginary permeability μ ′ ′ changes depending on the alloy composition of the soft magnetic powder and the shape of the powder. As the soft magnetic powder of the magnetic sheet, for example, Although a small amount of sendust (Fe-9.5Si-5.5Al) or the like may be used, such an alloy is hard and brittle, so it is difficult to form and process it into a flat powder.

  For example, Patent Document 1 describes that, in a relatively brittle Fe-Si-Al alloy, the addition of P improves the grindability during mechanical grinding. Specifically, in the Fe-based alloy powder containing 4 to 12% of Si and 3 to 8% of Al by weight, 0.001 to 0.5% of P is added. However, here, the crushability is evaluated by the time required to finely grind the powder with an attritor to a predetermined particle size, and it is not clear whether it becomes easy to process flat powder by the addition of P. .

  Generally, the Fe-Si-Al alloy increases the imaginary permeability μ "from around several MHz, but the Fe-Si-Cr alloy hardly increases the imaginary permeability μ" up to 10 MHz or more. Therefore, it is suitable for use in high frequency bands.

  For example, Patent Document 2 discloses the use of a soft magnetic powder made of an alloy obtained by adding P to an Fe-Si-Cr alloy as a magnetic sheet used for an antenna module of an RFID system used at 13.56 MHz. ing. By adding P to such an alloy, it is possible to facilitate flattening processing. In addition, it is stated that it is necessary to adjust the addition amount of P appropriately to secure the coercive force required to obtain a communication distance of 100 mm, and 0.2 to 0.5 wt% of P should be added. And

Japanese Patent Application Laid-Open No. 10-335126 JP, 2009-88087, A

  By increasing the aspect ratio by increasing and decreasing the particle size of the flat soft magnetic powder, the real magnetic permeability μ 'can be increased. Therefore, P is added to the Fe-Si-Cr alloy, but at this time, the crystal grains are easily refined, and the grain size becomes smaller in the flattening process, and as a result, the real permeability μ 'can not be increased. The

  The present invention has been made in view of such circumstances, and the object of the present invention is to provide a soft magnetic powder having high imaginary permeability and low imaginary permeability to a composite magnetic body by orientation dispersion. An object of the present invention is to provide an Fe-based alloy composition for this purpose, a composite magnetic body in which such soft magnetic powder is oriented and dispersed, and a method of producing the soft magnetic powder.

  The inventor of the present invention adjusts the composition of the alloy and suppresses the alloy powder prior to the flattening processing so as to suppress the refinement of the crystal grains and the grain size in the flattening processing of the Fe-Si-Cr alloy to which P is added. The heat treatment of was considered. Here, it is required that the alloy composition does not impair the magnetic properties of the composite magnetic body, and that it can be heat-treated without causing aggregation of the powder.

  That is, the Fe-based alloy composition according to the present invention is an Fe-based alloy composition having soft magnetic properties, and is, by mass%, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 It is characterized in that it has an alloy composition consisting of ̃4%, P: 0.02 to 1%, balance Fe and unavoidable impurities.

  According to this invention, the desired particle size and aspect ratio can be imparted by flattening processing of the alloy powder, and a composite magnetic body having a high imaginary permeability and a high real permeability can be provided.

  The soft magnetic powder according to the present invention is, by mass%, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, balance It is a flat alloy powder having an alloy composition comprising Fe and unavoidable impurities, and is characterized in that the average value of the aspect ratio of the particle diameter to the thickness is 100 or more.

  According to this invention, it is possible to provide a composite magnetic body having high real permeability while having low imaginary permeability.

  Further, the composite magnetic body according to the present invention is a composite magnetic body obtained by aligning and dispersing the soft magnetic flat alloy powder in the flattening direction of the flat alloy powder in a matrix material, and the flat alloy powder is Si in mass%. Cr: 2 to 6%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, balance Fe and an alloy composition consisting of unavoidable impurities and with respect to thickness It is characterized in that the average value of the aspect ratio of the particle diameter is 100 or more.

  According to this invention, a high real permeability can be obtained while having a low imaginary permeability, and the invention is suitable for a communication assistance application in which the communication distance via radio waves is made as long as possible.

  In the method of producing soft magnetic powder according to the present invention, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1 in mass%. A step of atomizing a molten alloy consisting of an Fe-based alloy composition having an alloy composition consisting of an iron and an unavoidable impurity, to obtain an alloy powder, giving a grain size adjusting heat treatment, and then performing flattening processing It is characterized by including.

  According to this invention, it is possible to provide a composite magnetic body having high real permeability while having low imaginary permeability.

  In the above-described invention, the grain size adjusting heat treatment is a heat treatment in which the grain size of the alloy powder is grown and kept at a temperature at which the P concentration is increased at least at the grain boundaries. Good. According to this invention, flattening processing can be facilitated, desired particle size and aspect ratio can be imparted with high accuracy, and composite magnetic bodies having high real permeability while having low imaginary permeability can be provided. .

It is (a) perspective view and (b) sectional drawing of the magnetic sheet by the composite magnetic body which used soft magnetic powder. It is a flowchart which shows the manufacturing method of the soft-magnetic powder and composite magnetic body by this invention. It is a figure which shows the result of the characteristic evaluation test of soft-magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of soft-magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of soft-magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of soft-magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of soft-magnetic powder and a magnetic sheet.

  A soft magnetic powder as one embodiment according to the present invention, and a composite magnetic body in which the soft magnetic powder is oriented and dispersed will be described with reference to FIG.

  As shown in FIG. 1, the magnetic sheet 10, which is a composite magnetic body, is a thin film-like rubber sheet made of a rubber-based resin 2 such as chlorinated polyethylene, and the flat flaky soft magnetic powder 1 is on the main surface It is a sheet-like composite magnetic body in which the orientation is dispersed in the direction along it. That is, the soft magnetic powder 1 is oriented and dispersed in the rubber-based resin 2 which is the matrix material, with the flattening direction being aligned. The magnetic sheet 10 is provided integrally with a wireless communication medium such as an RFID tag, for example, and is suitable for the communication assistance. That is, the magnetic sheet 10 guides the electromagnetic waves received by the antenna to the inside of the magnetic sheet 10 before reaching the peripheral metal members or the like, and allows transmission from the antenna as much as possible without loss.

  The soft magnetic powder 1 is made of an alloy obtained by adding P and Al in a predetermined amount to an Fe-Si-Cr alloy, and by mass%, 1.5 to 14% of Si, 2 to 6% of Cr, and 0 for Al 1 to 4%, containing 0.02 to 1% of P, and having an alloy composition consisting of the balance Fe and unavoidable impurities. Furthermore, as unavoidable impurities, C is 0.04% or less, Mn is 0.3% or less, S is 0.01% or less, N is 0.06% or less, Cu is 0.05% or less, Mo It is preferable to suppress Ni to 0.05% or less and 0.1% or less.

  In particular, the addition of P facilitates the flattening processing described later, but in the Fe-Si-Cr alloy to which P is added, the crystal grains are refined in the alloy powder before the flattening processing. It turned out that it was in the tendency. As a result, it is considered that the particle diameter of the soft magnetic powder obtained by the flattening processing becomes small, and a sufficient rolling effect can not be obtained, and the aspect ratio becomes small. In the present embodiment, as described above, while adding Al to the alloy, the grain size adjusting heat treatment is performed to appropriately coarsen the crystal grains before flattening processing. Even if the heat treatment temperature is relatively raised by the addition of Al, the alloy powder can not be agglomerated and the crystal grain size can be increased, and the other magnetic properties are not adversely affected. As a result, the soft magnetic powder 1 having a predetermined particle diameter and aspect ratio can be obtained, and the magnetic permeability characteristics required as the magnetic sheet for communication assistance to the magnetic sheet 10 as the composite magnetic body, that is, the low imaginary number It is possible to give high real permeability while maintaining permeability.

  Next, a method of manufacturing soft magnetic powder as one embodiment according to the present invention and a method of manufacturing a magnetic sheet using the soft magnetic powder will be described in detail with reference to FIG.

  As shown in FIG. 2, first, a molten alloy of a Fe-Si-Cr alloy of a predetermined alloy composition to which P and Al described above are added is atomized to obtain an alloy powder (powdering; S1). Here, a gas atomizing method in which molten metal is gas-sprayed is used. That is, an inert gas is blown while causing the molten alloy to flow down with a gas atomizing apparatus, and the molten alloy is divided into a large number of fine droplets, dropped and rapidly cooled and solidified to obtain an alloy powder. In particular, by adjusting the gas pressure or the like so that the average particle diameter D50 is 100 μm or more, a desired shape can be relatively easily given to the soft magnetic powder obtained in the flattening processing described later. . In addition, alloy powder can also be obtained by other atomizing methods, such as a water atomizing method.

Next, particle size adjustment heat treatment is performed on the obtained alloy powder (S2). In the grain size adjustment heat treatment, heating and holding at 900 to 1000 ° C. in an inert gas atmosphere of Ar or N _2, and appropriately coarsening crystal grains of the alloy powder after atomization refined by the addition of P .

  Further, the alloy powder is flattened and processed (S3). That is, the alloy powder is introduced into the container of the attritor apparatus together with an organic solvent, a grinding aid and the like, and a grinding medium such as steel balls is further loaded. And the stirring rod provided with the rotary blade in the surrounding surface is rotated, and the inside of a container is stirred. Then, the grinding medium collides with the alloy powder and gives an impact, and the alloy powder is flatly deformed and flattened while being crushed. The soft magnetic powder 1 is obtained by flattening it to a predetermined particle size. As the shape of the soft magnetic powder 1 obtained here, the average particle diameter D50 is set to less than 120 μm so as not to interfere with kneading and coating in compounding described later, and the magnetic sheet 10 is further provided with desired magnetic permeability characteristics. Preferably, the average aspect ratio is greater than 100 so that Moreover, it is preferable to make a particle size width (D90-D10) into 150 micrometers or less.

  In particular, as described above, since the crystal grains of the alloy powder refined by the addition of P are appropriately coarsened by the grain size adjustment heat treatment, it is possible to homogenize the variation of the grain size as a whole. Furthermore, the alloy powder may be ground preferentially at grain boundaries, and the grain size of the alloy powder ground during the flattening process may be made relatively large and homogenized. And while the particle size of the soft-magnetic powder 1 obtained is enlarged and an aspect-ratio is enlarged, a particle size width | variety can be made comparatively small. However, although the average particle diameter is made to be a predetermined value or less for compounding described later, this can be adjusted by the holding temperature of the particle diameter adjustment heat treatment or the like.

The obtained soft magnetic powder 1 is subjected to annealing heat treatment as required (S4). For example, the annealing heat treatment by heating to 300 to 400 ° C. under _{N 2,} held.

  Further, the soft magnetic powder 1 is composited (S5). In the compounding, in this example, the soft magnetic powder 1 is kneaded with a thermoplastic resin such as chlorinated polyethylene as a matrix material and other rubber resins, a dilution solvent and a crosslinking agent until it becomes a paste, and a paste is obtained. Get The obtained paste body is coated on a base material to a predetermined thickness by a doctor blade method to form a sheet while orientating the soft magnetic powder dispersed. Here, the filling amount of the soft magnetic powder 1 in the paste was 43% by volume, and the paste was applied to a thickness of 0.1 mm. Then, the sheet body is dried and crosslinked at a predetermined temperature to obtain the magnetic sheet 10.

  The soft magnetic powder 1 can be obtained as described above, and the magnetic sheet 10 can be obtained as a composite magnetic body using such soft magnetic powder. As described above, since the soft magnetic powder 1 can be provided with a predetermined particle size and aspect ratio, the magnetic sheet 10 using this can obtain the permeability characteristic required as a composite magnetic body for communication assistance. Can. The soft magnetic powder 1 can be similarly compounded to obtain a composite magnetic body having a shape other than a sheet shape.

[Characteristics evaluation test 1]
In the above-described manufacturing method, after obtaining the soft magnetic powder having the alloy composition shown in each of the examples and the comparative examples shown in FIGS. 3 to 6, a magnetic sheet was produced. The processing time required for the flattening processing during the preparation of each example and comparative example was recorded. In addition, the grain size of the alloy powder is measured after powderization (S1), and the grain size of the alloy powder and the presence or absence of aggregation are measured and evaluated after the grain size adjustment heat treatment (S2), and flattening is performed. After treatment (S3), the average particle diameter D50 and particle size width (D90-D10) of the soft magnetic powder are measured to calculate the aspect ratio, and after complexing (S5), the real permeability μ 'and imaginary number of the magnetic sheet The permeability μ ′ ′ and the loss coefficient tan δ (= μ ′ ′ / μ ′) were measured and calculated, and the corrosion resistance was evaluated.

  The heating and holding temperature of the grain size adjustment heat treatment (S2) was set to 1000 ° C., which is a typical temperature which can prevent aggregation of the alloy powder and relatively easily grow crystal grains. Further, for example, as shown in FIG. 6, the processing time of the flattening process (S3), that is, the operation time of the attritor, was adjusted so that the average particle diameter (D50) becomes maximum in each example and comparative example. .

  With regard to the crystal grain size of the alloy powder after powderization (S1) and particle size adjustment heat treatment (S2), the cut surface obtained by embedding and cutting out the obtained alloy powder in a resin is polished and a metallographic microscope is used. The polished surface was observed and determined by the line segment method.

  With or without aggregation of the alloy powder after particle size adjustment heat treatment (S2), 1 kg of the alloy powder is allowed to stand in a stainless steel vat and subjected to particle size adjustment heat treatment, and the alloy powder after cooling is observed. It evaluated by the presence or absence of the above aggregate.

  The average particle diameter D50 and the particle size width (D90-D10) of the soft magnetic powder after the flattening processing (S3) were each measured using a laser diffraction type particle size distribution measuring apparatus. The average particle diameter D50 is a particle diameter that makes the volume of the particle diameter distribution accumulated from the small diameter side 50% of the whole, and the particle diameter width (D90-D10) is the average particle diameter D90 and D10 (each accumulated from the small diameter side) The difference in particle size is 90% and 10%). Here, the target value of the average particle diameter D50 is less than 120 μm, and the target value of the particle size width is less than 150 μm.

Moreover, the average value of the aspect ratio was calculated as follows. That is, soft magnetic powder 1 is embedded in resin and polished, and the polished surface is observed with an optical microscope, and the average of the maximum thickness t _max and the minimum thickness t _min is obtained for any 100 particles of soft magnetic powder. , and particle thickness _{t a.} Furthermore, the average particle diameter D50 was divided by the average value t _ave of the particle thicknesses t _a for 100 particles to obtain an aspect ratio (average value). That is, the aspect ratio is calculated by the average value t _ave of average particle diameter D50 / particle thickness. Here, it is assumed that the target value of the aspect ratio is greater than 100.

  The real magnetic permeability μ ′ and the imaginary magnetic permeability μ ′ ′ of the magnetic sheet after compounding (S5) were measured as follows: The manufactured magnetic sheet was punched into a ring shape of outer diameter 10 mm × inner diameter 6 mm, The impedance characteristics were measured using a commercially available network analyzer with a measurement frequency of 13.56 MHz, and the real permeability μ ′ and the imaginary permeability μ ′ ′ were calculated. The loss coefficient tan δ was calculated by μ ′ ′ / μ ′. Here, the target value of the real permeability μ ′ is 60 or more. From the practical viewpoint, the target value of the loss coefficient tan δ is 0.10 It is assumed that

  The corrosion resistance of the magnetic sheet was evaluated by a high temperature and high humidity test. That is, it was exposed to an atmosphere of 85 ° C. and a relative humidity of 85%, and after 250 hours, it was visually observed and evaluated for the presence or absence of discoloration.

  As shown in FIG. 3, in this characterization test, first, the influence of the Si content was evaluated. That is, in Examples 1 to 9 and Comparative Examples 1 and 2, the content of Si was distributed between 0 and 16% by mass. In each example and comparative example, 2 mass% of Cr, 0.5 mass% of Al, and 0.5 mass% of P are contained. As a result, in Comparative Example 1 in which the content of Si was 0% by mass, the real magnetic permeability μ ′ was 28, which is much lower than the target value. Further, the average particle diameter D50 and the aspect ratio of the soft magnetic powder after flattening processing both tend to decrease as the content of Si increases, and in Comparative Example 2 in which the content of Si is 16 mass%. The aspect ratio is below the target value. It is considered that the alloy powder decreases in ductility, that is, becomes brittle as the content of Si increases. Examples 1 to 9 in which the content of Si was 1.5 to 14% by mass satisfied all target values. That is, the content of Si has an optimum range, which is in the range of 1.5 to 14% by mass.

  As shown in FIG. 4, the influence of the Cr content was further evaluated. That is, in Examples 6, 10 and 11 and Comparative Examples 3 and 4, the content of Cr was distributed between 0 and 8% by mass. In each example and comparative example, 8% by mass of Si, 0.5% by mass of Al, and 0.5% by mass of P are contained. Both the average particle diameter D50 and the aspect ratio of the soft magnetic powder after flattening processing tended to increase as the content of Cr is increased. It is considered that the toughness of the alloy powder is increased by the addition of Cr. In both of Comparative Example 3 in which the content of Cr is 0 mass% and Comparative Example 4 in which the content of Cr is 8 mass%, the real magnetic permeability μ ′ falls below the target value and the loss coefficient tan δ exceeds the target value. The Examples 6, 10 and 11 in which the content of Cr was 2 to 6% by mass satisfied all target values. That is, there is an optimal range in content of Cr, and it exists in the range of 2-6 mass%.

  As shown in FIG. 5, the influence by the content of Al was further evaluated. That is, in Examples 6, 12 to 18 and Comparative Examples 5 and 6, the content of Al was distributed between 0 and 5% by mass. In each example and comparative example, 8% by mass of Si, 2% by mass of Cr, and 0.5% by mass of P are contained. As a result, in Comparative Example 5 in which Al was not added, the alloy powder caused aggregation after the particle size adjustment heat treatment. In the other examples and comparative examples, the fact that aggregation can be suppressed by containing Al is considered to be due to the formation of an oxide film of Al on the surface of the alloy powder. Further, the evaluation of the corrosion resistance of Comparative Example 5 is also not good (x), and since it was good (o) in other Examples and Comparative Examples containing Al, the Al content improves the corrosion resistance of the magnetic sheet. It can be said that it contributes to On the other hand, in Comparative Example 6 in which the content of Al was 5% by mass, the average particle diameter D50 and the aspect ratio of the soft magnetic powder were smaller than those of the other examples, and were below the target value of the aspect ratio. If the content of Al exceeds 4% by mass, the ductility of the alloy powder is considered to be reduced. Examples 6 and 12 to 18 in which the content of Al was 0.1 to 4% by mass satisfied all target values. That is, there is an optimal range in content of Al, and it exists in the range of 0.1-4 mass%.

  As shown in FIG. 6, the influence of the P content was further evaluated. That is, in Examples 6 to 19 and Comparative Examples 7 to 9, the content of P was distributed between 0 and 1.5% by mass. In each example and comparative example, 8% by mass of Si, 2% by mass of Cr and 0.5% by mass of Al are contained. As a result, as the content of P is increased, the crystal grain size of the alloy powder after powdering (after spraying) and after the particle size adjustment heat treatment (after HT) tends to be smaller. In addition, as the content of P is increased, that is, as the grain size of the alloy powder after the grain size adjustment heat treatment is decreased, the average grain size D50 of the soft magnetic powder after the flattening process also tends to decrease. there were. In addition, about the processing time of the flattening process, it adjusted so that the average particle diameter (D50) of soft-magnetic powder could be made the largest. In Comparative Example 7 where P was not added, the grain size after spraying was relatively large, and the grain size and grain size range of the soft magnetic powder both exceeded the target values. Also in Comparative Example 8 in which the content of P is 0.01% by mass, the crystal grain size after spraying is relatively large, and the grain size of the soft magnetic powder has exceeded the target value. In Comparative Examples 7 and 8, no magnetic sheet was produced because it was difficult to apply both. Moreover, in Comparative Example 9 in which the content of P was 1.5% by mass, the real magnetic permeability μ ′ fell below the target value. Examples 6 and 19 to 26 in which the content of P was 0.02 to 1% by mass satisfied all target values. That is, the content of P has an optimum range, which is in the range of 0.02 to 1% by mass.

  As described above, the alloy powder after pulverization reduces its crystal grains by the inclusion of P, but the crystal grain size can be adjusted by the grain size adjustment heat treatment. In particular, by containing a predetermined amount of Al, aggregation of the alloy powder can be prevented and the grain size adjustment heat treatment can be performed even at 1000 ° C. which is a typical temperature at which the above-described crystal grains are easily grown. Incidentally, P is concentrated in the grain boundaries by the grain size adjustment heat treatment, and the alloy powder is easily broken at the grain boundaries in the flattening processing. In addition, the particle size of the soft magnetic powder by the flattening process depends on the size of the crystal grain after the particle size adjustment heat treatment which can be homogenized by the heat history. Therefore, the particle size of the soft magnetic powder can be homogenized, and the permeability of the magnetic sheet can be homogenized.

  As mentioned above, the alloy composition required as a Fe-based alloy composition for giving soft magnetic powder was shown. As for unavoidable impurities, C is 0.04% or less, Mn is 0.3% or less, and S is 0.01% or less by mass%, as a range that does not impair the magnetic properties and corrosion resistance of the soft magnetic powder described above. % Or less, N is 0.06% or less, Cu is 0.05% or less, Mo is 0.05% or less, and Ni is preferably 0.1% or less.

[Characteristics evaluation test 2]
In order to evaluate the influence of the heating and holding temperature of the particle size adjustment heat treatment (S2) among the manufacturing methods for obtaining the soft magnetic powder and the magnetic sheet from the Fe-based alloy composition of the above-mentioned alloy composition, The characteristic evaluation test about each temperature shown in FIG. 7 was done.

  In Comparative Example 10, 90% by mass of Fe, 8% by mass of Si, 2% by mass of Cr and Al and P are not added, and in the other examples and comparative examples, the same alloy as Example 6 described above Soft magnetic powder was obtained as a composition (see FIGS. 3 to 6). Similar to the above-mentioned characteristic evaluation test 1, the crystal grain size of the alloy powder is measured after the powderization (S1), and the grain size of the alloy powder and the presence or absence of aggregation after the grain size adjustment heat treatment (S2) The average particle diameter D50 of the soft magnetic powder was measured after the flattening processing (S3) to calculate the aspect ratio.

  As described above, the influence of the holding temperature of the particle size adjustment heat treatment was evaluated. That is, as shown in FIG. 7, the heating and holding temperature of the particle size adjustment heat treatment (S2) is 0 ° C. in Example 6, 27 and 28 and Comparative Examples 11 to 16 (the particle size adjustment heat treatment is not performed). It distributed between 1000 ° C. As a result, there was no significant change in crystal grain size after grain size adjustment heat treatment (after HT) with respect to crystal grain size after powdering (after spraying) to Comparative Examples 11 to 16 at 0 to 850 ° C., and thus obtained. The aspect ratio of the soft magnetic powder also fell below the target value. The crystal grain sizes after HT can be made relatively large at 900 ° C., 950 ° C. and 1000 ° C. in Examples 27, 28, and 6, and the aspect ratio of the soft magnetic powder also satisfies the target value. In particular, at 1000 ° C., it was found that these can be maximized in the examples. That is, a preferable range of the holding temperature of the particle size adjustment heat treatment is 900 to 1000 ° C.

  Here, in Comparative Example 10, the alloy composition does not contain Al and P, and the crystal grain size after spraying is larger than those of the other examples and comparative examples, and the holding temperature of the grain size adjusting heat treatment is 1000 ° C. Then, aggregation occurred. This result is consistent with the result (Comparative Example 7, Comparative Example 5) in the case where P or Al described in the property evaluation test 1 was not added.

  Although the representative embodiments according to the present invention and the modifications based thereon are described above, the present invention is not necessarily limited thereto. Various alternatives and modifications can be found by one skilled in the art without departing from the spirit of the invention or the scope of the appended claims.

1 Soft magnetic powder 10 Magnetic sheet

Claims (4)

Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, with an alloy composition consisting of the balance Fe and unavoidable impurities A soft magnetic powder, which is a flat alloy powder, and the average value of the aspect ratio of particle diameter to thickness is larger than 100. A composite magnetic body obtained by aligning and dispersing in a matrix material the flatting direction of a flat alloy powder having soft magnetism,
The flat alloy powder is, by mass%, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, balance Fe and unavoidable impurities What is claimed is: 1. A composite magnetic body having an alloy composition comprising: and having an average aspect ratio of grain size to thickness greater than 100. Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, with an alloy composition consisting of the balance Fe and unavoidable impurities Flattening processing is performed to atomize a molten alloy composed of an Fe-based alloy composition to obtain an alloy powder, and to give a grain size adjusting heat treatment, and then to make the average value of the aspect ratio of grain size to thickness larger than 100. A method of producing a soft magnetic powder comprising the step of applying. 4. The grain size adjusting heat treatment according to claim 3, wherein the grain size of the alloy powder is grown and maintained at a temperature at which the P concentration is increased at least at the grain boundaries while growing crystal grains of the alloy powder. Method of producing soft magnetic powder.

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