JP2017008376A - Fe-BASED ALLOY COMPOSITION, SOFT MAGNETIC POWDER, COMPOSITE MAGNETIC BODY AND MANUFACTURING METHOD OF SOFT MAGNETIC POWDER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soft magnetic powder providing high real number magnetic permeability as well as low imaginary number magnetic permeability to a composite magnetic body by oriented dispersion, an Fe-based alloy composition therefor, a composite magnetic body by oriented dispersing the soft magnetic powder and a manufacturing method of the soft magnetic powder.SOLUTION: An Fe-based alloy composition contains, by mass%, Si:1.5 to 14%, Cr:2 to 6%, Al:0.1 to 4%, P:0.02 to 1% and the balance Fe with inevitable impurities. A soft magnetic powder is a flat alloy powder having an alloy composition of the Fe-based alloy composition and has average of aspect ratio of particle diameter to thickness of 100 or more. A manufacturing method of the soft magnetic powder includes a process of flattening process after obtaining an alloy powder by atomizing alloy molten metal consisting of the Fe-based alloy composition and applying a particle diameter adjusting heat treatment on the same. A composite magnetic body is by oriented dispersion in a matrix material with fixing a flattening direction of the flat alloy powder.SELECTED DRAWING: None

Description

  The present invention relates to the soft magnetic powder used in 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 for producing the soft magnetic powder.

  In order to mount electronic components at a high density and reduce the size of electronic devices, interference due to electromagnetic waves generated from each electronic component becomes a problem. A sheet-like composite magnetic material is used for the purpose of reducing electromagnetic interference (EMI) inside such an electronic device. A magnetic sheet made of such a composite magnetic material is a resin sheet in which flat soft magnetic powder is oriented and dispersed in a matrix material made of resin, and this imaginary permeability μ ″ in a desired frequency band is increased, It uses magnetic loss to convert unwanted electromagnetic radiation into heat and absorb it.

  Also, flat soft magnetic powder is dispersed in the resin, which is provided integrally with a wireless communication medium such as an RFID tag, and is used for communication assistance in which the communication distance via radio waves is as long as possible. Similar magnetic sheets are used. In such a magnetic sheet, the electromagnetic wave received by the antenna is guided to the surrounding metal member before reaching the surrounding metal member and the like so that the transmission from the antenna can be performed with as little loss as possible. Here, the real number permeability μ ′ is increased while the imaginary permeability μ ″ is decreased.

  By the way, the magnetic permeability characteristic consisting of the real permeability μ ′ and the imaginary permeability μ ″ varies depending on the alloy composition of the soft magnetic powder and its powder shape. Examples of the soft magnetic powder of the magnetic sheet include magnetic properties. Sendust (Fe-9.5Si-5.5Al) or the like having a low isotropic property can be used, but such an alloy is hard and brittle, so that it is difficult to form 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 pulverizability during mechanical pulverization. Specifically, it is supposed that 0.001 to 0.5% of P is added to Fe-based alloy powder containing Si: 4 to 12% and Al: 3 to 8% by weight. However, here, the grindability is evaluated by the time required to finely pulverize the powder to a predetermined particle size with an attritor, and it is not certain whether it becomes easy to process into a flat powder by adding P. .

  In general, the Fe-Si-Al alloy increases the imaginary permeability μ ″ from around several MHz, while the Fe—Si—Cr alloy hardly increases the imaginary permeability μ ″ up to 10 MHz or more. Therefore, it is suitable for use in a high frequency band.

  For example, Patent Document 2 discloses the use of 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. Even in such an alloy, flattening processing can be easily performed by adding P. In addition, it is stated that it is necessary to appropriately adjust the addition amount of P in order to secure the coercive force necessary for obtaining a communication distance of 100 mm, and 0.2 to 0.5 wt% of P should be added. It is said.

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

  By the way, the real magnetic permeability μ ′ can be increased by increasing the aspect ratio by increasing the particle diameter of the flat soft magnetic powder. Therefore, P is added to the Fe—Si—Cr alloy. At this time, the crystal grains are easily refined, and the grain size is reduced in the flattening process. As a result, the real permeability μ ′ may not be increased. It was.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a soft magnetic powder that provides a high real number permeability while being low in imaginary permeability to a composite magnetic body by orientation dispersion. The present invention provides an Fe-based alloy composition, a composite magnetic material in which such soft magnetic powder is oriented and dispersed, and a method for producing the soft magnetic powder.

  In the flattening process of the Fe-Si-Cr alloy to which P is added, the inventor adjusts the alloy composition so as to suppress the refinement of the crystal grains and the particle diameter, and the alloy powder before the flattening process. The heat treatment was considered. Here, it is necessary to have an alloy composition that does not impair the magnetic properties of the composite magnetic body, and to be able to perform heat treatment without agglomerating the powder.

  That is, the Fe-based alloy composition according to the present invention is an Fe-based alloy composition having soft magnetism, and in terms of mass%, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 It has the alloy composition which consists of -4%, P: 0.02-1%, remainder Fe and an unavoidable impurity.

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

  Moreover, the soft magnetic powder according to the present invention is, in mass%, Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, the balance It is a flat alloy powder having an alloy composition composed of Fe and inevitable 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, a composite magnetic body having a high real number permeability while having a low imaginary number permeability can be provided.

  Further, the composite magnetic body according to the present invention is a composite magnetic body in which the flattening direction of the flat alloy powder having soft magnetism is aligned and dispersed in the matrix material, and the flat alloy powder is Si in mass%. : 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, the alloy composition consisting of the balance Fe and inevitable impurities, and with respect to the thickness The average value of the aspect ratio of the particle size is 100 or more.

  According to this invention, it is possible to obtain a high real magnetic permeability while having a low imaginary magnetic permeability, and it is suitable for a communication assisting application in which a communication distance via radio waves is to be made as long as possible.

  Moreover, the manufacturing method of the soft-magnetic powder by this invention is the mass%, Si: 1.5-14%, Cr: 2-6%, Al: 0.1-4%, P: 0.02-1 %, A molten alloy comprising an Fe-based alloy composition having an alloy composition comprising the balance Fe and inevitable impurities is atomized to obtain an alloy powder, followed by a grain size adjusting heat treatment followed by a flattening process. It is characterized by including.

  According to this invention, a composite magnetic body having a high real number permeability while having a low imaginary number permeability can be provided.

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

It is the (a) perspective view and (b) sectional view 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 a soft magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of a soft magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of a soft magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of a soft magnetic powder and a magnetic sheet. It is a figure which shows the result of the characteristic evaluation test of a soft magnetic powder and a magnetic sheet.

  A soft magnetic powder according to one embodiment of the present invention and a composite magnetic material obtained by orientation-dispersing the same will be described with reference to FIG.

  As shown in FIG. 1, a magnetic sheet 10 that is a composite magnetic material is a thin-film rubber sheet made of a rubber-based resin 2 such as chlorinated polyethylene, and has a flat thin piece of soft magnetic powder 1 on its main surface. It is a sheet-like composite magnetic material that is oriented and dispersed in a direction along the direction. That is, the soft magnetic powder 1 is oriented and dispersed in the rubber-based resin 2 that is a matrix material with the flattening direction aligned. The magnetic sheet 10 is provided integrally with a wireless communication medium such as an RFID tag, and is suitable for communication assistance. That is, the magnetic sheet 10 guides the electromagnetic wave received by the antenna into the magnetic sheet 10 before reaching the surrounding metal member and the like, and can perform transmission from the antenna with as little loss as possible.

  The soft magnetic powder 1 is made of an alloy obtained by adding a predetermined amount of P and Al to an Fe—Si—Cr alloy, and is 1.5% to 14% of Si, 2 to 6% of Cr, and 0 of Al in mass%. .1 to 4%, P is contained in an amount of 0.02 to 1%, and the alloy composition is composed of the remaining Fe and inevitable impurities. Further, 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 is contained. It is preferable to suppress 0.05% or less and Ni to 0.1% or less.

  In particular, the addition of P makes it possible to facilitate the flattening process 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 process. It turned out that there was a tendency. Thereby, it is considered that the particle diameter of the soft magnetic powder obtained by the flattening process is reduced, and a sufficient rolling effect cannot be obtained and the aspect ratio is reduced. In the present embodiment, as described above, while further adding Al to the alloy, the grain size adjusting heat treatment for appropriately coarsening the crystal grains is performed before the flattening process. Even if the heat treatment temperature is relatively increased by the addition of Al, the alloy powder is not aggregated and the crystal grain size can be increased, and other magnetic characteristics are not adversely affected. Thereby, the soft magnetic powder 1 having a predetermined particle diameter and aspect ratio can be obtained, and the magnetic permeability required for the magnetic sheet for assisting communication in the magnetic sheet 10 as a composite magnetic material, that is, a low imaginary number. Although the magnetic permeability is high, a high real number magnetic permeability can be provided.

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

  As shown in FIG. 2, first, the molten alloy of Fe—Si—Cr alloy having a predetermined alloy composition to which P and Al are added is atomized to obtain an alloy powder (powdering; S1). Here, a gas atomizing method of spraying molten metal was used. That is, an inert gas is blown while flowing molten alloy with a gas atomizer, and the molten alloy is divided into fine droplets, dropped, rapidly cooled and solidified to obtain 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 imparted 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, a particle size adjusting heat treatment is performed on the obtained alloy powder (S2). In the particle size adjustment heat treatment, the crystal grains of the alloy powder after spraying, which is heated and held at 900 to 1000 ° C. in an inert gas atmosphere with Ar or N ₂ and refined by addition of P, are appropriately coarsened. .

  Further, the alloy powder is flattened (S3). That is, the alloy powder is put into the container of an attritor apparatus together with an organic solvent and a grinding aid, and a grinding medium such as a steel ball is further loaded. And the inside of a container is stirred by rotating the stirring rod provided with the rotary blade in the surrounding surface. Then, the grinding medium collides with the alloy powder and gives an impact, and the alloy powder is flattened and flattened while being ground. The soft magnetic powder 1 is obtained by flattening 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 hinder kneading and coating in the later-described compounding, and the magnetic sheet 10 is given desired permeability characteristics. Therefore, it is preferable that the average value of the aspect ratio is larger than 100. Moreover, it is preferable that a particle size width (D90-D10) shall be 150 micrometers or less.

  In particular, since the crystal grains of the alloy powder refined by the addition of P as described above are appropriately coarsened by the grain size adjusting heat treatment, variations in crystal grain size can be homogenized as a whole. Furthermore, the alloy powder is pulverized preferentially at the crystal grain boundaries, and the alloy powder pulverized during the flattening process can have a relatively large particle size and can be homogenized. The obtained soft magnetic powder 1 can have a large particle size, a large aspect ratio, and a relatively small particle size range. However, although the average particle size is set to a predetermined value or less for compositing described later, this can be adjusted by the holding temperature of the particle size adjusting 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 compounded (S5). In this embodiment, in this example, the soft magnetic powder 1 is kneaded until it becomes a paste together with a thermoplastic resin such as chlorinated polyethylene as a matrix material, other rubber-based resin, a diluting solvent and a cross-linking material. Get. The obtained paste body is coated on a base material by a doctor blade method to form a sheet body while orienting the dispersed soft magnetic powder. 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 subjected to cross-linking press at a predetermined temperature to obtain the magnetic sheet 10.

  As described above, the soft magnetic powder 1 is obtained, and the magnetic sheet 10 can be obtained as a composite magnetic body using the soft magnetic powder. As described above, since the soft magnetic powder 1 can have a predetermined particle size and aspect ratio, the magnetic sheet 10 using the soft magnetic powder 1 can obtain permeability characteristics required as a composite magnetic body for communication assistance. Can do. Similarly, the soft magnetic powder 1 can be composited to obtain a composite magnetic body having a shape other than the sheet shape.

[Characteristic evaluation test 1]
In the manufacturing method described above, after obtaining a soft magnetic powder having the alloy composition shown in each of Examples and Comparative Examples shown in FIGS. The processing time required for the flattening processing during the production of each example and comparative example was recorded. Further, the crystal grain size of the alloy powder is measured after pulverization (S1), and the crystal grain size and the presence / absence of aggregation of the alloy powder are measured and evaluated after the grain size adjustment heat treatment (S2). After the processing (S3), the average particle diameter D50 and the particle size width (D90-D10) of the soft magnetic powder are measured to calculate the aspect ratio. The permeability μ ″ and the loss coefficient tan δ (= μ ″ / μ ′) were measured and calculated, and the corrosion resistance was evaluated.

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

  Regarding the crystal grain size of the alloy powder after pulverization (S1) and after the grain size adjustment heat treatment (S2), the cut surface obtained by embedding and cutting out the obtained alloy powder in a resin was polished, and a metal microscope was used. This polished surface was observed and determined by a line segment method.

  The presence or absence of agglomeration of the alloy powder after the particle size adjustment heat treatment (S2) was determined by placing 1 kg of the alloy powder on a stainless steel vat and subjecting it to a particle size adjustment heat treatment. Evaluation was made based on the presence or absence of the above aggregates.

  The average particle diameter D50 and the particle size width (D90-D10) of the soft magnetic powder after the flattening treatment (S3) were measured using a laser diffraction particle size distribution analyzer. The average particle size D50 is a particle size in which the volume obtained by accumulating the particle size distribution from the small diameter side is 50% of the whole, and the particle size width (D90-D10) is the average particle size D90 and D10 (accumulated from the small diameter side, respectively). The difference in particle size is 90% and 10% in volume. Here, the target value of the average particle diameter D50 was less than 120 μm, and the target value of the particle size width was less than 150 μm.

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

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

  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% relative humidity at 85 ° C., and was visually observed after 250 hours to evaluate whether or not there was discoloration.

  As shown in FIG. 3, in this characteristic evaluation test, first, the influence of the Si content was evaluated. That is, in Examples 1-9 and Comparative Examples 1 and 2, the Si content was distributed between 0 and 16% by mass. In each Example and Comparative Example, Cr is contained by 2% by mass, Al is contained by 0.5% by mass, and P is contained by 0.5% by mass. As a result, in Comparative Example 1 in which the Si content was 0 mass%, the real magnetic permeability μ ′ was 28, which was significantly lower than the target value. Further, as the Si content is increased, both the average particle diameter D50 and the aspect ratio of the soft magnetic powder after the flattening treatment tend to decrease. In Comparative Example 2 in which the Si content is 16% by mass, The aspect ratio has fallen below the target value. As the Si content increases, the alloy powder is considered to decrease ductility, that is, become brittle. Examples 1 to 9 in which the Si content was 1.5 to 14% by mass satisfied all target values. That is, the Si content has an optimum range, and 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 Cr content was distributed between 0 and 8 mass%. In each Example and Comparative Example, Si is contained by 8% by mass, Al by 0.5% by mass, and P by 0.5% by mass. As the Cr content was increased, both the average particle diameter D50 and the aspect ratio of the soft magnetic powder after the flattening treatment tended to increase. It is thought that the toughness of the alloy powder was increased by the addition of Cr. In Comparative Example 3 in which the Cr content was 0% by mass and Comparative Example 4 in which the Cr content was 8% by mass, the real permeability μ ′ was lower than the target value and the loss coefficient tan δ exceeded the target value. It was. Examples 6, 10 and 11 in which the Cr content was 2 to 6% by mass satisfied all target values. That is, the Cr content has an optimum range, and is in the range of 2 to 6% by mass.

  As shown in FIG. 5, the influence of the Al content 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 to 5% by mass. In each of Examples and Comparative Examples, Si is contained by 8% by mass, Cr is contained by 2% by mass, and P is contained by 0.5% by mass. As a result, in Comparative Example 5 in which Al was not added, the alloy powder agglomerated after the particle size adjusting heat treatment. In other examples and comparative examples, the reason why aggregation was suppressed by the inclusion of Al is considered to be because an Al oxide film was formed on the surface of the alloy powder. In addition, the evaluation of the corrosion resistance of Comparative Example 5 was also poor (x), and in other examples and comparative examples containing Al, it was good (◯), so the inclusion of Al improved 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 Al content was 5% by mass, the average particle diameter D50 and the aspect ratio of the soft magnetic powder were small compared to the other examples, which was lower than the target value of the aspect ratio. If the Al content exceeds 4% by mass, it is considered that the ductility of the alloy powder is lowered. Examples 6 and 12 to 18 in which the Al content was 0.1 to 4% by mass satisfied all target values. That is, there is an optimal range for the Al content, which is in the range of 0.1 to 4% by mass.

  As shown in FIG. 6, the influence by the P content was further evaluated. That is, in Examples 6, 19 to 26, and Comparative Examples 7 to 9, the P content was distributed between 0 to 1.5 mass%. In each Example and Comparative Example, Si is contained by 8% by mass, Cr by 2% by mass, and Al by 0.5% by mass. As a result, the crystal grain size of the alloy powder after pulverization (after spraying) and after the grain size adjusting heat treatment (after HT) tended to decrease as the P content increased. In addition, as the P content is increased, that is, as the crystal grain size of the alloy powder after the grain size adjusting heat treatment is reduced, the average grain size D50 of the soft magnetic powder after the flattening process tends to be reduced. there were. The processing time for the flattening processing is adjusted so as to maximize the average particle diameter (D50) of the soft magnetic powder. In Comparative Example 7 in which P was not added, the crystal grain size after spraying was relatively large, and both the particle size and the particle size width of the soft magnetic powder exceeded the target values. Also in Comparative Example 8 in which the P content was 0.01% by mass, the crystal grain size after spraying was relatively large, and the particle size of the soft magnetic powder exceeded the target value. In Comparative Examples 7 and 8, since it was difficult to perform coating, a magnetic sheet was not produced. Further, in Comparative Example 9 in which the P content was 1.5 mass%, the real permeability μ ′ was lower than the target value. Examples 6 and 19 to 26 in which the P content was 0.02 to 1% by mass satisfied all target values. That is, there is an optimum range for the content of P, which is in the range of 0.02 to 1% by mass.

  As described above, the alloy powder after pulverization reduces the crystal grains by the inclusion of P, but the crystal grain size can be adjusted by a grain size adjusting heat treatment. In particular, by containing a predetermined amount of Al, it is possible to perform the grain size adjusting heat treatment while preventing aggregation of the alloy powder even at a typical temperature of 1000 ° C. at which the above-described crystal grains are easily grown. Note that P is concentrated at the crystal grain boundary by the grain size adjusting heat treatment, and the alloy powder is easily broken at the crystal grain boundary in the flattening process. Further, the particle size of the soft magnetic powder by the flattening processing depends on the size of the crystal grains after the particle size adjusting heat treatment that can be homogenized by the thermal history. Therefore, the particle diameter of the soft magnetic powder can be homogenized, and the magnetic permeability characteristics of the magnetic sheet can be homogenized.

  As described above, an alloy composition required as an Fe-based alloy composition for giving a soft magnetic powder was shown. As for the unavoidable impurities, the mass percentage, C is 0.04% or less, Mn is 0.3% or less, and S is 0.01, as long as the magnetic properties and corrosion resistance of the soft magnetic powder are not impaired. %, 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.

[Characteristic evaluation test 2]
Among the manufacturing methods for obtaining a soft magnetic powder and a magnetic sheet from an Fe-based alloy composition having the above-described alloy composition, in particular, in order to evaluate the influence of the heating / holding temperature of the particle size adjustment heat treatment (S2), A characteristic evaluation test for each temperature shown in FIG. 7 was performed.

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

  As described above, the influence of the holding temperature of the particle size adjusting heat treatment was evaluated. That is, as shown in FIG. 7, in Examples 6, 27 and 28 and Comparative Examples 11 to 16, the heating / holding temperature of the particle size adjusting heat treatment (S2) is 0 ° C. (no particle size adjusting heat treatment is performed). Sorted between ~ 1000 ° C. As a result, there was no significant change in the crystal grain size after the grain size adjustment heat treatment (after HT) with respect to the crystal grain size after pulverization (after spraying) up to Comparative Examples 11 to 16 at 0 to 850 ° C. The aspect ratio of the soft magnetic powder was also below the target value. If Examples 27, 28 and 6 were 900 ° C., 950 ° C., and 1000 ° C., the crystal grain size after HT could be made relatively large, and the aspect ratio of the soft magnetic powder also met the target value. In particular, it was found that these could be maximized in the examples at 1000 ° C. That is, the preferable range of the holding temperature of the particle size adjusting heat treatment is 900 to 1000 ° C.

  Here, in Comparative Example 10, the alloy composition does not contain Al and P, the crystal grain size after spraying becomes larger than that of the other Examples and Comparative Examples, and the holding temperature of the grain size adjusting heat treatment is 1000 ° C. Aggregation then occurred. This result agrees with the results (Comparative Example 7 and Comparative Example 5) when P or Al described in the characteristic evaluation test 1 is not added.

  So far, representative examples and modifications based thereon have been described, but the present invention is not necessarily limited thereto. Those skilled in the art will recognize a variety of alternative embodiments and modifications without departing from the spirit of the invention or the scope of the appended claims.

1 Soft magnetic powder 10 Magnetic sheet

Claims (5)

  Fe-based alloy composition having soft magnetism, in mass%, Si: 1.5-14%, Cr: 2-6%, Al: 0.1-4%, P: 0.02-1% And an Fe-based alloy composition comprising an alloy composition comprising the balance Fe and inevitable impurities.   It has an alloy composition consisting of Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, the balance Fe and inevitable impurities. A soft magnetic powder which is a flat alloy powder and has an average aspect ratio of particle diameter to thickness of 100 or more. A composite magnetic material in which the flattening direction of a flat alloy powder having soft magnetism is aligned and dispersed in a matrix material,
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%, the balance Fe and inevitable impurities A composite magnetic body characterized in that the average value of the aspect ratio of the particle diameter to the thickness is 100 or more.   It has an alloy composition consisting of Si: 1.5 to 14%, Cr: 2 to 6%, Al: 0.1 to 4%, P: 0.02 to 1%, the balance Fe and inevitable impurities. A method for producing a soft magnetic powder, comprising the steps of: obtaining an alloy powder by atomizing a molten alloy comprising an Fe-based alloy composition;   The grain size adjusting heat treatment is a heat treatment in which the crystal grains of the alloy powder are grown and heated and held at a temperature at which the P concentration is increased at least at the grain boundaries in the grains. Method for producing soft magnetic powder.

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