JP5490556B2 - Fe-based soft magnetic alloy powder, method for producing the same, and magnetic sheet using the Fe-based soft magnetic alloy powder - Google Patents

Description

  The present invention relates to an Fe-based soft magnetic alloy powder and a magnetic sheet having both a high performance coefficient Q and a real part μ ′ of complex relative permeability.

  A magnetic sheet for an antenna (for example, a magnetic sheet for RFID) is required to be thin and have a real part μ ′ having a high complex relative permeability and a performance coefficient Q.

  Conventionally, magnetic sheets using ferrite or Sendust (registered trademark), Fe-Si based sheets, and the like have been used as magnetic sheets.

  However, in both cases, it is difficult to combine both the real part μ ′ having a high complex relative permeability and the performance coefficient Q.

Pamphlet of International Publication No. 2007/013436 JP 2007-266031 A JP 2005-40759 A JP-A-3-211259 JP-A-2-125801 JP-A-2005-57444 JP 2008-251735 A JP 2006-157540 A JP 2007-281074 A JP 2003-45708 A JP 2002-289414 A JP 2009-59752 A JP-A-11-269509

  Therefore, the present invention is for solving the above-described conventional problems, and in particular, even when an alloy powder is prepared by a method with a low cooling rate such as an atomizing method, the real part of the performance coefficient Q and the complex relative permeability after heat treatment. It is an object of the present invention to provide an Fe-based soft magnetic alloy powder having a high μ ′, a method for producing the same, and a magnetic sheet using the Fe-based soft magnetic alloy powder.

The Fe-based soft magnetic alloy powder in the present invention is composed of a structure having at least a bcc phase by heat-treating an alloy having an amorphous phase as a main phase, and Tx1 / Tm ( end) is a Fe-based soft magnetic alloy powder having a composition of 0.5 or more in terms of K. Here, Tx1 indicates the crystallization start temperature of the bcc phase in the DSC curve, and Tm (end) is the temperature at the end of the endothermic curve (temperature when the heat flow returns from the endothermic peak indicating the melting point Tm to the baseline). ) it is intended to show the,
Composition formula is represented by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is B, P, at least any one of a C, Y is, Nb, at least one of Mo 1 The seed, Q, is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at%, 1 at% ≦ c ≦ 6 at%, 0 at% ≦ d. ≦ 5 at%, 0 at% ≦ e ≦ 5 at%, and the structure is composed of a multiphase structure having the bcc phase and a second crystal phase having an X-ray diffraction peak different from the bcc phase, and the bcc phase wherein the the peak intensity (I _1), the peak intensity of the second crystalline phase (I ₂₎ the peak intensity of the ratio (I ₂ / I ₁₎ is 0.02 to 0.15.

  Tx1 / Tm is an important factor in forming a uniform fine crystal structure. The Fe-based soft magnetic alloy powder of the present invention is, for example, manufactured by an atomizing method and then subjected to heat treatment to precipitate a bcc phase and a crystalline phase, and Tx1 / Tm (end) is adjusted as described above. By doing so, the amorphous phase can be mainly formed in the state before the heat treatment. Thus, when the state before the heat treatment is mainly amorphous, a uniform fine crystal structure can be formed by the heat treatment. In addition, the atomization method can obtain a uniform spherical alloy powder compared to the liquid quenching method in which an alloy is obtained as a metal ribbon, but it is difficult to become amorphous due to the low cooling rate of the molten alloy, but Tx1 / Tm (end) By adjusting the above as described above, it becomes easy to obtain a spherical alloy powder mainly composed of amorphous even by the atomizing method.

The composition ratio of S i a is more preferably not less than 3at%.

The Fe-based soft magnetic alloy powder of the present invention has a second crystal phase having an X-ray diffraction peak different from the bcc phase in addition to the bcc phase. The second crystal phase is a compound phase or an elemental phase containing an element other than Fe, and in particular, the precipitated phase is considered to be a (FeSi) ₃ B phase, an Fe ₂ Nb phase, or the like. In the present invention, with the bcc phase of the peak intensity (I _1), the peak intensity of the second crystalline phase (I ₂₎ the peak intensity of the ratio (I ₂ / I ₁₎ as a 0.02 to 0.15 Yes. In the state where only the bcc phase is precipitated, the real part μ ′ of the complex relative permeability can be made relatively high, but the performance coefficient Q is low. When the second crystal phase precipitates, the performance coefficient Q increases, while the real part μ ′ of the complex relative permeability starts to decrease. Therefore, in the present invention, the peak intensity ratio (I ₂ / I ₁ ) is adjusted as described above, the crystal phase is slightly precipitated, and the performance coefficient is reduced without greatly reducing the real part μ ′ of the complex relative permeability. Q is increased, thereby increasing both the real part μ ′ of the complex relative permeability and the performance coefficient Q.

In the present invention, the peak intensity ratio (I ₂ / I ₁ ) is preferably 0.02 or more and 0.08 or less.

  In the present invention, the average crystal grain size of the bcc phase is preferably 50 nm or less. By making the crystal structure fine in this way, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be effectively increased.

  Further, in the present invention, it is possible to obtain a uniform spherical alloy powder mainly composed of an amorphous material by the atomizing method, so that a fine and uniform structure can be formed by subsequent heat treatment. At this time, the average crystal grain size of the bcc phase can be reduced to 50 nm or less, and by making such a fine crystal structure, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be effectively increased. .

In the present invention, the average particle size of the alloy powder is preferably in the range of 30 .mu.m to 100 .mu.m. In the present invention, the average particle diameter of the alloy powder is more preferably 60 μm or more.

  The magnetic sheet according to the present invention includes a matrix material and a flat powder formed of the Fe-based soft magnetic alloy powder described above. According to the magnetic sheet of the present invention, the performance coefficient Q at 13.56 MHz can be made 10 or more and the real part μ ′ of the complex relative permeability can be made 30 or more. Further, in the present invention, by adjusting the average particle size of the flat Fe-based soft magnetic alloy powder as described above, both the real part μ ′ of the complex relative permeability at 13.56 MHz and the performance coefficient Q are The real number part μ ′ of the complex relative permeability at 13.56 MHz can be adjusted to 50 or more, more preferably 60 or more, and the performance factor Q can be adjusted to 20 or more. It becomes possible.

In addition, the manufacturing method of the Fe-based soft magnetic alloy powder in the present invention is mainly composed of an amorphous single phase or an amorphous phase by an atomizing method from an alloy having a Tx1 / Tm (end) of 0.5 or more in terms of K. Produced an Fe-based soft magnetic alloy powder,
Tx1 indicates the crystallization start temperature of the bcc phase in the DSC curve, and Tm (end) is the temperature at the end of the endothermic curve (temperature when the heat flow returns from the endothermic peak indicating the melting point Tm to the baseline). are shown the composition formula is represented by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is B, P, at least any one of a C, Y is, Nb, at least one of Mo Any one of them, Q is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at%, 1 at% ≦ c ≦ 6 at%, 0 at % ≦ d ≦ 5 at%, 0 at% ≦ e ≦ 5 at%,
Further heat treatment is performed to precipitate a bcc phase and a second crystal phase having an X-ray diffraction peak different from the bcc phase ,
The heat treatment temperature is set to be higher than the crystallization start temperature (Tx1) of the bcc phase and lower than 100 ° C. than the crystallization start temperature (Tx2) of the second crystal phase. .

As a result, both the bcc phase and the second crystal phase are appropriately precipitated to form a uniform fine crystal structure, and the bcc phase X-ray diffraction peak intensity (I ₁ ) and the second crystal phase X-ray diffraction The peak intensity ratio (I ₂ / I ₁ ) with respect to the peak intensity (I ₂ ) can be adjusted easily and appropriately so that it falls within the range of 0.02 to 0.15.

In the present invention, the pre-Symbol heat treatment temperature, the second than the crystallization starting temperature of the crystalline phase (Tx2), it is preferable to set the lower temperature within the range of 55 ° C. to 70 ° C..

  In the above, the Fe-based soft magnetic alloy powder is preferably flattened, and at this time, the average particle size of the alloy powder is preferably in the range of 30 μm to 100 μm, followed by the heat treatment. This makes it possible to manufacture a magnetic sheet having a real part μ ′ having a complex relative permeability of 50 or more, preferably 60 or more, and a performance coefficient Q of 20 or more with a thin sheet thickness of several hundreds of μm.

  According to the present invention, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be effectively increased.

Schematic diagram of RFID device and reader / writer DSC curve diagram showing the definition of Tx1, Tx2, Tm (start), Tm (end), A graph showing the relationship between Tx1 / Tm (end) and the structure before heat treatment (immediately after quenching); A graph showing the relationship between processing time and D50 when flattening Fe-based soft magnetic alloy powder; SEM photograph of flattened Fe-based soft magnetic alloy powder, SEM photograph showing the cross-sectional state of the magnetic sheet, X-ray diffraction diagram with respect to the heat treatment temperature of each example shown in Table 1, X-ray diffractogram with respect to heat treatment temperature in Fe _71.5at% Si _13.5at% Nb ₃ Cu ₁ B ₉ Cr ₂ and enlarged X-ray diffractogram partially enlarged An Fe-based soft magnetic alloy powder having the same composition as in Example 9, an X-ray diffraction diagram for a sample whose processing conditions are different from Example 9, and an enlarged X-ray diffraction diagram in which a part thereof is enlarged, X-ray diffraction diagram of Example 9, A graph showing the relationship between the heat treatment temperature of each example and the average crystal grain size Gs of the bcc phase and the average crystal grain size Gs of the second crystal phase; A graph showing the relationship between the heat treatment temperature of each example and the peak intensity ratio (I ₂ / I ₁ ); A graph showing the relationship between the peak intensity ratio (I ₂ / I ₁ ) of each example (magnetic sheet), the real part μ ′ ^{(13.56 MHz) of the} complex relative permeability, and the performance coefficient Q; A graph showing the relationship between the heat treatment temperature of each example (magnetic sheet) and the real part μ ′ ^{(13.56 MHz)} and imaginary part μ ″ ^{(13.56 MHz)} of the complex relative permeability, and the real part of the complex relative permeability a graph showing the relationship between μ ′ ^{(13.56 MHz)} and the performance factor Q; A graph showing the frequency dependence of the real part μ ′ and the imaginary part μ of the complex relative permeability in the magnetic sheet of this example, A graph showing the frequency dependence of the real part μ ′ and the imaginary part μ of the complex relative permeability in the magnetic sheet of Sendust (registered trademark) (comparative example); A graph showing the frequency dependence of the real part μ ′ and the imaginary part μ of the complex relative permeability in the Fe—Si based magnetic sheet (comparative example); It is a SEM photograph of the flat powder used for the experiment of Table 2, (a) SEM photograph of the flat powder classified at 38 μm or less, (b) SEM photograph of the flat powder without classification, (c) is 38 μm or more SEM photograph of classified flat powder, The magnetic sheet of each sample shown in Table 2, the magnetic sheet using the Fe-Si alloy powder, the magnetic sheet using the Fe-based amorphous alloy powder, and the Fe-Si-Al alloy powder (Sendust (registered trademark)) are used. A graph showing the relationship between the real part μ ′ ^{(13.56 MHz)} of the complex relative permeability and the performance coefficient Q in the magnetic sheet, FIG. 17 shows the relationship between the average particle diameter (D50) of the flat powder and the real part μ ′ ^{(13.56 MHz)} of the complex relative permeability of the magnetic sheet when the performance coefficient Q is about 20. Graph.

FIG. 1 is a schematic diagram of an RFID device and a reader / writer.
As shown in FIG. 1, an RFID (Radio Frequency ID) device 1 includes an antenna circuit 2 having an antenna and an IC chip, a metal member 3, and a magnetic sheet inserted between the antenna circuit 2 and the metal member 3. 4. Normally, communication is possible only with the antenna circuit 2, but it is indispensable that the antenna circuit 2 is disposed on the metal member 3 (conductor) because of the structure of the product. Communication is possible by arranging the magnetic sheet 4 between the metal member 3.

The antenna circuit 2 has a form in which an antenna and an IC chip are formed on a substrate.
The metal member 3 forms a part of the housing, for example. The magnetic sheet 4 of this embodiment inserted between the antenna circuit 2 and the metal member 3 will be described later.

  As shown in FIG. 1, by inserting the magnetic sheet 4 between the antenna circuit 2 and the metal member 3, the magnetic flux H from the reader / writer 10 passes through the magnetic sheet 4, and the RFID device 1, the reader / writer 10, A reflux magnetic flux can be formed between the two. Normally, a frequency of 13.56 MHz is used in RFID communication. As a result, it is possible to effectively improve RFID characteristics at 13.56 MHz.

  The magnetic sheet 4 in the present embodiment includes, for example, flattened Fe-based soft magnetic alloy powder and a matrix material. As the matrix material, silicone resin, polypropylene, chlorinated polyethylene, polyethylene, acrylic resin, ethylene / propylene / diene / terpolymer (EPDM), chloroprene, polyurethane, vinyl chloride, saturated polyester, nitrile resin, and the like can be selected. Further, phosphoric acid esters, red phosphorus, antimony trioxide, carbon black, magnesium hydroxide, aluminum hydroxide, hexabromobenzene, melamine derivatives, bromine-based, chlorine-based, platinum-based flame retardants may be added.

  The content of the Fe-based soft magnetic alloy powder is preferably in the range of 30 to 70% by volume. Thereby, desired sheet characteristics can be obtained.

  In order to manufacture the magnetic sheet 4, first, an alloy powder is prepared by a water atomization method in which a molten Fe-based soft magnetic alloy is jetted into water and rapidly cooled. The method for producing the Fe-based soft magnetic alloy powder is not limited to the water atomizing method, and a gas atomizing method may be used. Moreover, about the process conditions of the water atomization method and the gas atomization method, the conditions normally performed according to the kind of raw material can be used. On the other hand, the quenched ribbon manufactured by the liquid quenching method is easy to obtain an amorphous alloy, but it is difficult to pulverize the ribbon into a uniform fine flat powder. It is preferable to manufacture in the form.

  Then, after classifying the obtained spherical Fe-based soft magnetic alloy powder to make the particle size uniform, the alloy powder is flattened. Various mills such as an attritor, a bead mill, a ball mill, and a pin mill can be used as the mill used for flattening, but it is particularly preferable to use a bead mill. Thereafter, heat treatment is performed under predetermined conditions. The heat treatment conditions will be described later.

  Next, after mixing said flat powder with the liquid material of the matrix material which comprises the magnetic sheet 4, and producing a liquid mixture, the magnetic sheet 4 is produced by forming a liquid mixture into a sheet. The sheet molding method is preferably a doctor blade method or extrusion molding. The heat treatment described above may be performed after being formed into a magnetic sheet, or may be performed on both after being formed into a magnetic sheet together with the production stage of the Fe-based soft magnetic alloy powder. .

  Although the thickness of the magnetic sheet 4 of the present embodiment is not particularly limited, sheet characteristics suitable for a device using the magnetic sheet can be obtained even if the thickness of the magnetic sheet 4 is reduced, specifically, less than 1 mm. Can be obtained. In this embodiment, even if the thickness of the magnetic sheet is set to 0.5 mm or less, and further 0.2 mm or less, good sheet characteristics can be obtained. Moreover, in the Example mentioned later, the thickness of the magnetic sheet 4 is thinly formed to about 100 micrometers.

  In the Fe-based soft magnetic alloy powder in this embodiment, Tx1 / Tm (end) is 0.5 or more in K conversion. Tx1 / Tm (end) is preferably 0.55 or more.

  FIG. 2 shows a DSC curve (an example) of the Fe-based soft magnetic alloy powder of Example 2 described later in the present embodiment. As shown in FIG. 2, at least two exothermic peaks appear in the DSC curve. The exothermic peak on the low temperature side indicates the precipitation of the bcc phase, and the temperature at the beginning of the exothermic curve (the temperature at which the heat flow starts to rise from the baseline toward the exothermic peak) is the crystallization start temperature Tx1 of the bcc phase. . The exothermic peak on the high temperature side indicates the precipitation of the second crystal phase, and the temperature at the beginning of the exothermic curve is the crystallization start temperature Tx2 of the crystal phase. Here, the second crystal phase is a crystal phase that appears at the next highest temperature after the first crystal phase (bcc phase), and does not prevent the third crystal phase from appearing. In addition, values such as Tx1, Tx2, and Tm are values measured under conditions of a heating rate of 20 ° C./min.

  As shown in FIG. 2, an endothermic peak exhibiting a melting point Tm appears on the higher temperature side than the exothermic peak. The temperature at the beginning of this endothermic curve (the temperature at which the heat flow begins to fall from the baseline toward the endothermic peak) is Tm (start), and the temperature at the end (the heat flow rises from the endothermic peak at which the melting point Tm is indicated) Tm (end) is the temperature when the temperature returns to.

  Tx1 / Tm (end) is an important factor in forming a uniform fine crystal structure. The Fe-based soft magnetic alloy powder of the present embodiment is prepared by, for example, producing an alloy powder mainly composed of an amorphous single phase or an amorphous phase by an atomizing method, and then performing heat treatment to precipitate the bcc phase and the second crystal phase. However, by adjusting Tx1 / Tm (end) as described above, the amorphous phase can be mainly formed in the state before the heat treatment (the state immediately after the rapid cooling). Here, “amorphous main body” means that the entire structure may be an amorphous phase, or there may be a slight amount of crystalline (about 50% or less, more preferably 30% or less) other than the amorphous phase. Point to. Thus, when the state before the heat treatment (the state immediately after the rapid cooling) is mainly amorphous, a uniform fine crystal structure can be formed by the subsequent heat treatment.

In addition, the Fe-based soft magnetic alloy powder subjected to the predetermined heat treatment in the present embodiment is composed of a multiphase structure having a bcc phase and a second crystal phase having an X-ray diffraction peak different from the bcc phase. Is preferred. Further, the bcc phase of the peak intensity (I _1), the peak intensity of the second crystalline phase (I ₂₎ the peak intensity of the ratio (I ₂ / I ₁₎ is in the 0.02 to 0.15. The peak intensity ratio (I ₂ / I ₁ ) is preferably 0.02 or more and 0.08 or less.

Thus, the Fe-based soft magnetic alloy powder of the present embodiment has a second crystal phase having an X-ray diffraction peak different from the bcc phase in addition to the bcc phase. The bcc phase is an α-Fe single phase or Fe solid solution. The second crystal phase is a compound phase or a single phase containing an element other than Fe. The compound phase is considered to be (FeSi) ₃ B phase, Fe ₂ Nb phase, or the like. The second crystal phase may exist in a plurality of phases having different X-ray diffraction peaks.

In this embodiment, the bcc phase of the peak intensity (I _1), setting the peak intensity of the second crystalline phase (I ₂₎ the peak intensity of the ratio (I ₂ / I ₁₎ to 0.02 to 0.15 However, the second crystal phase is slightly precipitated. Here, as the peak intensity of the bcc phase and the peak of the second crystal phase, the maximum peak recognized from the X-ray diffraction result was used. The peak intensity (I ₁ ) of the bcc phase is a diffraction peak near d = 2.015 ＝ (2θ = 52.7 ° in X-ray diffraction using a wavelength of λ = 1.903), and the diffraction peak of the compound phase is It is a relatively easy-to-understand peak near d = 2.089Å (2θ = 50.7 ° by X-ray diffraction using a wavelength of λ = 1.903Å). Thereby, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be increased.

  In this embodiment, the average crystal grain size of the bcc phase can be finely crystallized to 50 nm or less. The above average crystal grain size is a numerical range of the original powder that does not flatten the Fe-based soft magnetic alloy. Even in the alloy powder after flattening, the average crystal grain size of the bcc phase is reduced to 50 nm or less. Can be By making the crystal structure fine in this way, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be effectively increased.

Fe-based soft magnetic alloy powder in the present embodiment, for example, the composition formula is indicated by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is B, P, at least one of C 1 Species, Y is at least one of Nb and Mo, Q is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at %, 1 at% ≦ c ≦ 6 at%, 0 at% ≦ d ≦ 5 at%, and 0 at% ≦ e ≦ 5 at%. In particular, the composition ratio a of Si is preferably 3 at% or more. Thereby, the state before the heat treatment (the state immediately after the rapid cooling) can be easily formed mainly by the amorphous body, and Tx1, Tx2, Tm (end), etc. can be easily adjusted to be within a predetermined range.

  And according to the magnetic sheet 4 having the above-described flat Fe-based soft magnetic alloy powder (flat powder), the performance coefficient Q particularly at 13.56 MHz is 10 or more, and the real part μ ′ of the complex relative permeability is Can be increased to 30 or more.

In this embodiment, a flat powder Fe-based soft magnetic alloy powder is given above of _{Fe 100-abcde Si a X b} Y c Cr d Q e, the average particle diameter of the alloy powder is in the range of 30μm~100μm It is preferable to be within. The average particle size of the alloy powder is a 50% cumulative particle size (D50), measured with a particle size distribution meter (Microtrac MT3000 from Nikkiso).

  The average particle diameter (D50) of the alloy powder is preferably 60 μm or more, more preferably 63 μm or more, and further preferably 70 μm or more.

  The aspect ratio (aspect ratio) of the flat powder is in the range of 10 to 800, and the thickness is about 0.1 μm to 100 μm, preferably 0.1 μm to 10 μm.

  In this embodiment, in the magnetic sheet 4 containing the flat powder having the above composition having an average particle diameter (D50) of 30 μm to 100 μm, both the performance coefficient Q at 13.56 MHz and the real part μ ′ of the complex relative permeability are Easy to adjust to be larger. Specifically, the performance coefficient Q at 13.56 MHz can be adjusted to 20 or more, and the real part μ ′ of the complex relative permeability can be adjusted to 50 or more. Furthermore, by making the average particle diameter (D50) of the flat powder 60 μm or more, more preferably 63 μm or more, the performance coefficient Q at 13.56 MHz is 20 or more, and the real part μ ′ of the complex relative permeability is 60. It becomes possible to adjust above.

  As shown in the experiment described later, in order to increase both the real part μ ′ of the complex relative permeability and the performance coefficient Q, it is effective that the average particle diameter (D50) of the flat powder is large. The average particle size of the spherical Fe-based soft magnetic alloy powder (original powder) itself formed by the atomization method or the like must be large. However, there is a limit to producing a base powder having a large particle size, and even if the average particle size of the base powder can be formed to be quite large, cracking and the like are likely to occur when the base powder is flattened. It was difficult to form an average particle size (D50) of the flat powder larger than 100 μm. Therefore, in this embodiment, the upper limit of the average particle diameter (D50) of the flat powder is set to 100 μm.

  In the present embodiment, in the above composition formula, the Si composition ratio a is preferably in the range of 3.2 at% to 20.5 at%, 12.5 at% to 20.5 at%, and further 13.5 at%. More preferably, it is within the range of ˜15.5 at%.

  In this embodiment, the element X contains at least B, and the composition ratio of B is preferably in the range of 6 at% to 10.5 at%, more preferably in the range of 6.2 at% to 10.5 at%. . Furthermore, the composition ratio of B is more preferably in the range of 6.5 at% to 9 at%.

  The element Y contains at least Nb, and the composition ratio of Nb is preferably in the range of 2 at% to 5.5 at%, 3 at% to 4 at%.

  The Cr composition ratio d is preferably 1 at% to 4 at%, 1 at% to 3 at% or less. The element Q contains at least Cu, and the composition ratio of Cu is preferably greater than 0 at% and 2 at% or less, and 0.5 at% to 1 at%.

  In the present embodiment, the Fe-based soft magnetic alloy powder is Fe—Si—Nb—Cu—B—Cr, Fe—Si—Nb—Cu—B, Fe—Nb—Si—P—C—B—Cu, Fe -Nb-Si-B-Cu-Al, Fe-Mo-Nb-P-B, and the like are preferable.

  In this embodiment, the Fe-based soft magnetic alloy powder is adjusted within the more limited composition range described above, and the average particle size (D50) of the flat powder is within a range of 30 μm to 100 μm, preferably 60 μm or more. Thus, the performance coefficient Q at 13.56 MHz of the magnetic sheet 4 containing the flat powder is more effectively 20 and the real part μ ′ of the complex relative permeability is 50 or more (preferably 60 or more). It is possible to adjust so that.

  In the present embodiment, both the performance coefficient Q at 13.56 MHz and the real part μ ′ of the complex relative permeability can be appropriately and easily increased as described above. Therefore, the maximum communication distance L1 between the reader / writer 10 and the RFID device 1 shown in FIG. 1 can be increased. In particular, in the present embodiment, both the real part μ ′ of the complex relative permeability and the performance coefficient Q can be effectively increased with a thin sheet thickness of about several hundred μm, and the RFID device 1 can be made thin and excellent. Communication characteristics can be obtained.

  In the method for producing the Fe-based soft magnetic alloy powder of this embodiment, a predetermined heat treatment is performed to precipitate both the bcc phase and the second crystal phase from the amorphous main state as shown in the DSC curve of FIG. At this time, the heat treatment temperature is set higher than the crystallization start temperature (Tx1) of the bcc phase and lower than 100 ° C. than the crystallization start temperature (Tx2) of the second crystal phase. Here, Tx2 is the crystallization start temperature that appears next to the crystallization start temperature Tx1 of the bcc phase in the DSC curve when measured at a temperature increase rate of 20 ° C./min. Further, the heat treatment time is set to 5 min or more and 240 min or less.

As a result, both the bcc phase and the second crystal phase can be appropriately precipitated to form a uniform fine crystal structure, and the bcc phase X-ray diffraction peak intensity (I ₁ ) and the second crystal phase X-ray diffraction can be formed. The peak intensity ratio (I ₂ / I ₁ ) to the peak intensity (I ₂ ) can be adjusted easily and appropriately so that it falls within the range of 0.02 to 0.15. In the present invention, even if the heat treatment is performed at a temperature lower than 100 ° C. below the crystallization start temperature (Tx2) of the second crystal phase, the second crystal phase precipitates if the heat treatment is performed for a certain time. Is.

In this embodiment, the composition formula is represented by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is, B, P, at least any one of a C, Y is, Nb, the Mo At least one of them, Q is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at%, 1 at% ≦ c ≦ 6 at% , 0 at% ≦ d ≦ 5 at%, and 0 at% ≦ e ≦ 5 at%, an Fe-based soft magnetic alloy powder is produced by an atomizing method or the like.

  Then, after classifying the obtained spherical Fe-based soft magnetic alloy powder (original powder) to uniform the particle size, the original powder is flattened. At this time, the average particle size of the flat Fe-based soft magnetic alloy powder (flat powder) is in the range of 30 μm to 100 μm, and then the heat treatment is performed. The average particle size of the alloy powder is a 50% cumulative particle size (D50), measured with a particle size distribution meter (Microtrac MT3000 from Nikkiso).

  The average particle size (D50) of the flat powder described above can be obtained by adjusting the size of the average particle size of the base powder and the size of the sieves in the classifier.

  In this embodiment, it is more preferable to set the heat treatment temperature to a temperature lower than the crystallization start temperature (Tx2) of the second crystal phase within a range of 55 ° C to 70 ° C.

  In the magnetic sheet 4 having the flat powder and the matrix material obtained as described above, both the real part μ ′ of the complex relative permeability at 13.56 MHz and the performance coefficient Q can be increased more effectively. Specifically, the real part μ ′ of the complex relative permeability can be increased to 50 or more (preferably 60 or more) and the performance coefficient Q can be increased to 20 or more.

  Fe-based soft magnetic alloy powder having the composition shown in Table 1 below was produced by the water atomization method.

  As shown in the “AS-Q structure” column of Table 1, it was found that the entire structures of Comparative Examples 1 and 2 were almost crystalline before the heat treatment (immediately after quenching). It was found that all the examples were mainly composed of an amorphous phase.

  Each sample was subjected to differential scanning calorimetry (temperature increase rate of 20 ° C./min) to obtain a DSC curve shown in FIG. 2, and Tx1, Tx2, Tx3, and Tm (end) were measured. Here, both Tx2 and Tx3 indicate the crystallization temperature of the second crystal phase. The crystallization start temperature is in the order of Tx1 <Tx2 <Tx3.

Further, as shown in Table 1, Tx1 / Tm (end) of each sample was obtained in K conversion.
FIG. 3 shows the relationship between Tx1 / Tm (end) (K conversion) and the structure before heat treatment (immediately after rapid cooling).

  As shown in FIG. 3, it was found that by setting Tx1 / Tm (end) to 0.5 or more, it can be mainly amorphous. Here, the “amorphous main body” refers to a state in which an amorphous single phase or an amorphous body is a main body and a slight amount of crystal is precipitated.

  It was also found that the entire structure can be made into an amorphous single phase by setting Tx1 / Tm (end) to 0.55 or more.

  Subsequently, the Fe-based soft magnetic alloy powder was flattened. Flattening was performed using a bead mill. The change in the average particle size (D50: histogram average particle size) of the alloy powder at that time is shown in FIG. The average particle size (D50) of the alloy powder was measured with a particle size distribution meter (Microtrac MT3000 from Nikkiso). FIG. 4 is a graph showing the relationship between the processing time and the average particle diameter (D50) of the alloy powder when flattening a plurality of samples having the composition of Example 9. In the initial stage, the Fe-based soft magnetic alloy powder is crushed by the mill medium, becomes flattened, and the average particle diameter (D50) of the alloy powder increases, but by further processing, the powder is broken, The average particle diameter (D50) of the alloy powder gradually decreases. In this experiment, the average particle diameter (D50) of the alloy powder can be finally set to about 40 to 60 μm.

  In addition, the bead mill processing time in Example 9 was 21 hours. The bead mill processing time was also 21 hours for the other samples shown in Table 1.

  FIG. 5 is an SEM photograph of the flat Fe-based soft magnetic alloy powder. As shown in FIG. 5, it was found that a thin flat powder having a substantially uniform thickness was obtained. In this embodiment, it is preferable to obtain a flat powder having a thickness of about 0.1 μm to 100 μm, preferably about 10 μm or less and a D50 of about 20 to 80 μm.

Subsequently, the flat powder was heat-treated in N ₂ or in an inert gas. The heat treatment temperature was 550 to 800 ° C., and the heat treatment time was 30 minutes. And it knead | mixed with chlorinated polyethylene and shape | molded the sheet | seat. The sheet thickness was 100 μm. The content of the Fe-based soft magnetic alloy powder with respect to the matrix material (chlorinated polyethylene) was 32.5 to 50% by volume.

  The cross-sectional state of the magnetic sheet obtained by the above is shown in the SEM photograph of FIG. As shown in FIG. 6, it was found that the flat powder was oriented in a substantially planar direction and laminated in the height direction via a matrix material (chlorinated polyethylene).

  Subsequently, each of the samples of Examples 4 to 7 and 9 shown in Table 1 was subjected to a heat treatment temperature of 600 ° C. to 800 ° C. (600 ° C. to 640 ° C. for Example 9) for 30 minutes. The X-ray diffraction result of a sample is shown.

  In addition, in experiment, it performed with respect to both the original powder which has not been flattened, and flat powder. 7 (a) and 7 (b) are experimental results for Example 7, (a) is the original powder, and (b) is the flat powder (average particle size (D50) = 64 μm). . 7 (c) and 7 (d) are experimental results for Example 6, (c) is the original powder, and (d) is the flat powder (average particle size (D50) = 42 μm). . The X-ray diffraction of FIG.7 (e) (f) is an experimental result with respect to Example 5, (e) is a base powder, (f) is a flat powder (average particle diameter (D50) = 54 micrometer). . The X-ray diffraction of FIGS. 7 (g) and 7 (h) is the experimental result for Example 4, (g) is the original powder, and (h) is the flat powder (average particle size (D50) = 62 μm). . The X-ray diffraction of FIG. 7 (i) is an experimental result with respect to the flat powder of Example 9 (average particle diameter (D50) = 62 μm).

FIGS. _{7J and 7K} are an X-ray diffraction diagram with respect to the heat treatment temperature in Fe _{71.5 at%} Si _{13.5 at%} Nb ₃ Cu ₁ B ₉ Cr ₂ and an enlarged X-ray diffraction diagram in which a part thereof is enlarged. The sample was processed with a bead mill for 5.5 hours.

  FIGS. 7 (l) and 7 (m) are Fe-based soft magnetic alloy powders having the same composition as in Example 9, and an X-ray diffraction pattern for a sample whose processing conditions are different from those in Example 9 and an enlarged view of a part thereof. It is an X-ray diffraction diagram. The sample was processed with a bead mill for 6 hours.

Analysis by X-ray diffraction was carried out by the following method.
X-ray diffraction was performed by a diffractometer method using a Co target with an output of 40 kV, 200 mA, a scanning angle 2θ = 30 to 110 °. As a result, the measurement was further performed at a scanning angle 2θ = 45 to 60 ° centering on 2θ = 52 ° where a relatively strong intensity was observed. The measurement at 2θ = 45 to 60 ° was performed by the step scan method (FT method) with a step angle of 0.02 ° and a measurement time of 1 second.

  The intensity analysis was performed using the Co-Kα1 wavelength (1.789 mm) after the background treatment. After the heat treatment, the product of the present invention has an intensity peak around 2θ = 52 °, which is a peak corresponding to the bcc phase. In addition, in the heat treatment at a certain temperature or more, a plurality of precipitation peaks that appear to be compound phases are observed, and in particular, the peak observed at 2θ = 50 to 51 ° is relatively large and is seen after the low-temperature heat treatment. For example, in the X-ray diffraction pattern (enlarged view) of the samples shown in FIGS. 7 (j) to (m), the peak starts to appear after annealing at 605 to 610 ° C.

As shown in each figure of FIG. 7 (note that the samples of FIGS. 7 (j) to (m) will be described in detail later), as the heat treatment temperature is raised, the bcc phase precipitates and the heat treatment is further performed. It was found that as the temperature was raised, a second crystal phase showing a diffraction peak different from the diffraction peak of the bcc phase began to precipitate. This second crystal phase is considered to be a compound phase or a single phase containing elements other than Fe, such as (FeSi) ₃ B phase, Fe ₂ Nb phase, and the like.

  As described above, all the samples of this example were mainly amorphous before the heat treatment (immediately after the rapid cooling), but by performing the heat treatment, the amorphous phase was crystallized, and the bcc phase and further the second crystal phase (Fe It was found that other compound phases and simple substance phases) were precipitated.

  Further, the X-ray diffraction of Example 9 in FIG. 7 (i) will be described in detail. First, the bcc phase starts to precipitate at a heat treatment temperature of about 600 ° C., and the second crystal phase other than the bcc phase is obtained at the heat treatment temperature of about 625 ° C. Was found to begin to precipitate.

FIG. 8 is an X-ray diffraction pattern of Example 9. In the experiment, heat treatment at 650 ° C. was performed on Example 9, and X-ray diffraction was measured with a heat treatment time of 30 minutes. Here, the measurement conditions of X-ray diffraction were measured using a Co target having a wavelength of 1.789 (Kα ₁ ).

As shown in FIG. 8, in addition to the diffraction peak showing the bcc phase at 2θ = 52 to 53 °, a diffraction peak showing the second crystal phase was observed. As shown in FIG. 8, diffraction peaks (1) and (2) appear at an interplanar spacing of d = 2.06 (2θ = 51.6 °) and d = 2.09 (2θ = 50.7 °). As shown in FIG. 8, the peak of the compound phases (1) and (2) is the largest diffraction peak among the diffraction peaks other than the bcc phase, but has a very small intensity compared to the diffraction peak showing the bcc phase. . Note that I ₂ of the peak intensity ratio (I ₂ / I ₁₎ to be described below are not intended peak of the compound phase (1) of a second crystalline phase that is not necessarily detected. In that case, the peak intensity ratio (I ₂ / I ₁ ) is specified at the peak corresponding to the compound phase (2).

  Subsequently, the relationship between the heat treatment temperature and the average crystal grain size Gs of the bcc phase and the second crystal phase was measured using the samples of Examples 4 to 7 and 9 in Table 1. The heat treatment time was 30 minutes. The average crystal grain size Gs was determined from the X-ray diffraction diagram using the Scherrer equation.

  FIGS. 9A to 9C show the experimental results of Example 7. FIG. 9A shows the average crystal grain size Gs of the bcc phase in the base powder and the flat powder, and FIG. The average crystal grain size Gs of the second crystal phase in the flat powder is shown, and FIG. 9C shows the average crystal grain size Gs of the second crystal phase in the base powder. 9B and 9C show the average crystal grain sizes of the plurality of second crystal phases (1) and (2) that exist as shown in FIG. The same applies to FIGS. 9 (e), (f), (h), (i), (k), and (l).

  9 (d) to (f) show the experimental results of Example 6. FIG. 9 (d) shows the average crystal grain size Gs of the bcc phase in the base powder and the flat powder, and FIG. The average crystal grain size Gs of the second crystal phase in the flat powder is shown, and FIG. 9F shows the average crystal grain size Gs of the second crystal phase in the base powder.

  9 (g) to (i) show the experimental results of Example 5. FIG. 9 (g) shows the average crystal grain size Gs of the bcc phase in the base powder and the flat powder, and FIG. 9 (h) The average crystal grain size Gs of the second crystal phase in the flat powder is shown, and FIG. 9 (i) shows the average crystal grain size Gs of the second crystal phase in the base powder.

  9 (j) to (l) are the experimental results of Example 4, FIG. 9 (j) shows the average crystal grain size Gs of the bcc phase in the base powder and the flat powder, and FIG. 9 (k) The average crystal grain size Gs of the second crystal phase in the flat powder is shown, and FIG. 9 (l) shows the average crystal grain size Gs of the second crystal phase in the base powder.

  9 (m) to (n) show the experimental results of Example 9. FIG. 9 (m) shows the average crystal grain size Gs of the bcc phase in the flat powder, and FIG. 9 (n) shows the flat powder. 2 shows the average crystal grain size Gs of the second crystal phase in FIG. In FIG. 9 (n), the average crystal grain size Gs of the second crystal phase (2) showing the diffraction peak (2) in FIG. 8 was determined.

  As shown in FIGS. 9 (a) (d) (g) (j) (m), the average crystal grain size of the bcc phase in each sample is 50 nm or less and is refined to about 10 to 40 nm. Also in the case of powder, the average crystal grain size was found to be about 10 to 35 nm. It was also found that when the heat treatment temperature was set to about 600 ° C. to 650 ° C., the average crystal grain size of the bcc phase could be made 30 nm or less, or 20 nm or less.

  As shown in FIGS. 9 (b), (e), (h), (k), and (n), in each sample (flat powder), the average crystal grain size of the second crystal phase was refined to about 10 to 40 nm. I found out. Moreover, as shown to FIG.9 (c) (f) (i) (l), also in each sample (original powder), the average crystal grain diameter of the 2nd crystal phase is refined | miniaturized to about 10-70 nm. I understood it.

Subsequently, the heat treatment temperature and the peak intensity ratio (I ₂ / I ₁ ) were determined using the samples of Examples 4 to 7 and 9 in Table 1. The heat treatment time was 30 minutes. In the experiment, X-ray diffraction with respect to the heat treatment temperature of each sample was measured, and with respect to the X-ray diffraction shown in FIG. 8, the diffraction peak intensities (I ₂ ) of the second crystal phases (1) and ( ₂ ) and bcc The diffraction peak intensity (I ₁ ) of the phase was determined, and the peak intensity ratio (I ₂ / I ₁ ) of each second crystal phase to the bcc phase was determined. The experimental results are shown in FIG.

10 (a) and 10 (b) show the experimental results of Example 7. FIG. 10 (a) shows the peak intensity ratio (I ₂ / I ₁ ) in the flat powder, and FIG. The peak intensity ratio (I ₂ / I ₁ ) in the powder is shown.

10 (c) and (d) show the experimental results of Example 6. FIG. 10 (c) shows the peak intensity ratio (I ₂ / I ₁ ) in the flat powder, and FIG. The peak intensity ratio (I ₂ / I ₁ ) in the powder is shown.

10 (e) and (f) are the experimental results of Example 5, FIG. 10 (e) shows the peak intensity ratio (I ₂ / I ₁ ) in the flat powder, and FIG. The peak intensity ratio (I ₂ / I ₁ ) in the powder is shown.

10 (g) and (h) are the experimental results of Example 4, FIG. 10 (g) shows the peak intensity ratio (I ₂ / I ₁ ) in the flat powder, and FIG. The peak intensity ratio (I ₂ / I ₁ ) in the powder is shown.

FIG. 10 (i) shows the experimental results of Example 9, and FIG. 10 (i) shows the peak intensity ratio (I ₂ / I ₁ ) in the flat powder.

As shown in FIG. 10, it was found that the peak intensity ratio (I ₂ / I ₁ ) tends to increase as the heat treatment temperature increases. This is presumably because the precipitation of the second crystal phase is promoted.

Next, by using the magnetic sheet having the flattened Fe-based soft magnetic alloy powder of Examples 4 to 7 and 9 in Table 1, the peak intensity ratio (I ₂ / I ₁ ) and the real part μ of the complex relative permeability μ The relationship between ´ ^{(13.56 MHz)} and the performance factor Q was investigated. The experimental results are shown in FIG.

11A and 11B show the experimental results of the magnetic sheet of Example 7. FIG. 11A shows the peak intensity ratio (I ₂ / I ₁ ) and the real part μ ′ ⁽ complex relative permeability). ^{13.56 MHz)} and FIG. 11B shows the relationship between the peak intensity ratio (I ₂ / I ₁ ) and the performance coefficient Q. The real part μ ′ and the imaginary part μ ″ of the complex relative permeability at a frequency of 13.56 MHz were obtained by an impedance analyzer. The reciprocal of the loss tan θ was defined as the performance coefficient Q.

11C and 11D show the experimental results of the magnetic sheet of Example 6. FIG. 11C shows the real part μ ′ ⁽ peak intensity ratio (I ₂ / I ₁ ) and complex relative permeability. shows the relationship between the ^{13.56 MHz),} FIG. 11 (d) shows the relationship between peak intensity ratio (I ₂ / I ₁₎ and the performance factor Q.

FIGS. 11E and 11F show the experimental results of the magnetic sheet of Example 5. FIG. 11E shows the peak intensity ratio (I ₂ / I ₁ ) and the real part μ ′ ⁽ complex relative permeability). shows the relationship between the ^{13.56 MHz),} FIG. 11 (f) shows the relationship between peak intensity ratio (I ₂ / I ₁₎ and the performance factor Q.

FIGS. 11 (g) and 11 (h) show experimental results of the magnetic sheet of Example 4. FIG. 11 (g) shows the peak intensity ratio (I ₂ / I ₁ ) and the real part μ ′ ⁽ complex relative permeability). shows the relationship between the ^{13.56 MHz),} FIG. 11 (h) shows the relationship between peak intensity ratio (I ₂ / I ₁₎ and the performance factor Q.

11 (i) and (j) show the experimental results of the magnetic sheet of Example 9, and FIG. 11 (i) shows the peak intensity ratio (I ₂ / I ₁ ) and the real part μ ′ ⁽ complex relative permeability). shows the relationship between the ^{13.56 MHz),} FIG. 11 (j) shows the relationship between peak intensity ratio (I ₂ / I ₁₎ and the performance factor Q.

As shown in FIG. 11, it was found that as the peak intensity ratio (I ₂ / I ₁ ) increases, the real part μ ′ of the complex relative permeability tends to decrease, while the performance coefficient Q tends to increase.

FIG. 12 shows the real part μ ′ ^{(13.56 MHz)} and the imaginary part μ ″ ^{(13.56 MHz)} of the complex relative permeability with respect to the heat treatment temperature of each sample (magnetic sheet) of Examples 4 to 7 and 9 in Table 1, and the performance coefficient. 4 is a graph showing the relationship between Q and the relationship between the real part μ ′ ^{(13.56 MHz)} of the complex relative permeability and the performance coefficient Q.

12A to 12C show the experimental results of the magnetic sheet of Example 7. FIG. 12A shows the heat treatment temperature, the real part μ ′ ^{(13.56 MHz)} and the imaginary part of the complex relative permeability. mu "graph showing the relationship between the ^{(13.56 MHz),} FIG. 12 (b), a graph showing the relationship between the heat treatment temperature and the performance coefficient Q, FIG. 12 (c), the real part of the complex relative permeability Myu' ^{( 13} is a graph showing the relationship between ^{13.56 MHz)} and performance coefficient Q.

12D to 12F show the experimental results of the magnetic sheet of Example 6, and FIG. 12D shows the heat treatment temperature, the real part μ ′ ^{(13.56 MHz)} and the imaginary part of the complex relative permeability. mu "graph showing the relationship between the ^{(13.56 MHz),} FIG. 12 (e) graph showing the relationship between the heat treatment temperature and the performance coefficient Q, FIG. 12 (f), the real part of the complex relative permeability Myu' ^{( 13} is a graph showing the relationship between ^{13.56 MHz)} and performance coefficient Q.

12 (g) to (i) are experimental results of the magnetic sheet of Example 5. FIG. 12 (g) shows the heat treatment temperature, the real part μ ′ ^{(13.56 MHz)} and the imaginary part of the complex relative permeability. mu "graph showing the relationship between the ^{(13.56 MHz),} FIG. 12 (h) is a graph showing the relationship between the heat treatment temperature and the performance coefficient Q, FIG. 12 (i), the real part of the complex relative permeability Myu' ^{( 13} is a graph showing the relationship between ^{13.56 MHz)} and performance coefficient Q.

12 (j) to (l) show the experimental results of the magnetic sheet of Example 4. FIG. 12 (j) shows the heat treatment temperature, the real part μ ′ ^{(13.56 MHz)} and the imaginary part of the complex relative permeability. mu "graph showing the relationship between the ^{(13.56 MHz),} FIG. 12 (k) is a graph showing the relationship between the heat treatment temperature and the performance coefficient Q, FIG. 12 (l) is the real part of the complex relative permeability Myu' ^{( 13} is a graph showing the relationship between ^{13.56 MHz)} and performance coefficient Q.

12 (m) and (n) show the experimental results of the magnetic sheet of Example 9. FIG. 12 (m) shows the heat treatment temperature, the real part μ ′ ^{(13.56 MHz)} and the imaginary part μ of the complex relative permeability. ″ ^{(13.56 MHz)} is a graph showing the relationship between ^{(13.56 MHz)} , FIG. 12 (n) is a graph showing the relationship between the heat treatment temperature and the performance coefficient Q.

Table 2 summarizes the experimental results shown in FIGS.
First, considering Example 7 (the average particle diameter (D50) of alloy powder (D50) = 64 μm) with reference to FIGS. 9 to 12 and Table 2, the real number of the complex relative permeability gradually increases by performing heat treatment at 585 ° C. or higher. It was found that the part μ ′ decreased and the performance coefficient Q gradually increased. For example, when a heat treatment temperature of about 625 ° C. (a temperature higher than Tx1 and lower than 100 ° C. than Tx2) is applied, the real part μ ′ of the complex relative permeability is about 40 and the performance coefficient Q is about 100. It turns out that it is obtained. At this time, the average crystal grain size Gs of the bcc phase (Fe-based soft magnetic alloy powder is flat powder) is about 14 nm, and the average crystal grain size Gs of the second crystal phase (Fe-based soft magnetic alloy powder is flat powder) is The crystal structure was 40 nm or less, and the peak intensity ratio (I ₂ / I ₁ ) was about 0.03 to 0.07 (3% to 7%).

Next, considering Example 6 (average particle diameter of alloy powder (D50) = 42 μm), when the heat treatment temperature is 625 ° C. or higher, the real part μ ′ of the complex relative permeability gradually decreases and the performance coefficient Q was found to be high. For example, when a heat treatment temperature of about 675 ° C. (a temperature higher than Tx1 and lower than 100 ° C. than Tx2) is applied, the real part μ ′ of the complex relative permeability is about 40 and the performance coefficient Q is about 10, both being high. It turns out that a numerical value is obtained. At this time, the average crystal grain size Gs of the bcc phase (Fe-based soft magnetic alloy powder is a flat powder) is about 22 nm, and the average crystal grain of the second crystal phase (Fe-based soft magnetic alloy powder is a flat powder). The diameter Gs was a fine crystal structure of 30 nm or less, and the peak intensity ratio (I ₂ / I ₁ ) was about 0.03 to 0.12 (3% to 12%).

Next, considering Example 5 (average particle diameter of alloy powder (D50) = 54 μm), when the heat treatment temperature is 600 ° C. or higher, the real part μ ′ of the complex relative permeability gradually decreases, and the performance coefficient Q was found to be high. For example, when a heat treatment temperature of about 650 ° C. (a temperature higher than Tx1 and lower than 100 ° C. than Tx2) is applied, the real part μ ′ of the complex relative permeability is about 60 and the performance coefficient Q is about 10, both being high. It turns out that a numerical value is obtained. At this time, the average crystal grain size Gs of the bcc phase (Fe-based soft magnetic alloy powder is a flat powder) is about 15 nm, and the average crystal grain of the second crystal phase (Fe-based soft magnetic alloy powder is a flat powder). The diameter Gs was a fine crystal structure of 40 nm or less, and the peak intensity ratio (I ₂ / I ₁ ) was about 0.01 to 0.04 (1% to 4%).

Next, considering Example 4 (average particle diameter of alloy powder (D50) = 62 μm), when the heat treatment temperature is 600 ° C. or higher, the real part μ ′ of the complex relative permeability gradually decreases, and the performance coefficient Q was found to be high. For example, when a heat treatment temperature of about 650 ° C. (a temperature higher than Tx1 and lower than 100 ° C. than Tx2) is applied, the real part μ ′ of the complex relative permeability is about 40 and the performance coefficient Q is about 10, both being high. It turns out that a numerical value is obtained. At this time, the average crystal grain size Gs of the bcc phase (Fe-based soft magnetic alloy powder is a flat powder) is about 14 nm, and the average crystal grain of the second crystal phase (Fe-based soft magnetic alloy powder is a flat powder). The diameter Gs was a fine crystal structure of 30 nm or less, and the peak intensity ratio (I ₂ / I ₁ ) was about 0.06 to 0.10 (6% to 10%).

Next, considering Example 9 (average particle diameter of alloy powder (D50) = 62 μm), when the heat treatment temperature is 600 ° C. or higher, the real part μ ′ of the complex relative permeability gradually decreases and the coefficient of performance Q was found to be high. For example, when a heat treatment temperature of about 625 ° C. (a temperature higher than Tx1 and lower than 100 ° C. than Tx2) is applied, the real part μ ′ of the complex relative permeability is about 80, and the performance coefficient Q is about 10, both being high. It turns out that a numerical value is obtained. At this time, the average crystal grain size Gs of the bcc phase (flat powder) is about 14 nm, the average crystal grain size Gs of the second crystal phase (flat powder) is a fine crystal structure of 40 nm or less, and the peak intensity ratio ( I ₂ / I ₁ ) was about 0.04 to 0.10 (4% to 10%).

13 is a graph showing the frequency dependence of the real part μ ′ and the imaginary part μ ″ of the complex relative permeability of the magnetic sheet using the Fe-based soft magnetic alloy (flat powder) of Example 9. The content of the Fe-based soft magnetic alloy was 50% by volume, the average particle size (D50) of the alloy powder was 50.60 μm, and the density was 3.1 g / cm ³ . The heat treatment time was 620 ° C. and 90 minutes.

  14 is a graph showing the frequency dependence of the real part μ ′ and the imaginary part μ ″ of the complex relative permeability of a magnetic sheet using Sendust (registered trademark). FIG. 15 is a graph showing the frequency dependence of the Fe—Si based magnetic sheet. It is a graph which shows the frequency dependence of the real part μ 'and the imaginary part μ "of the complex relative permeability.

  In the magnetic sheet using Sendust (registered trademark) shown in FIG. 14, the real part μ ′ of the complex relative permeability at 13.56 MHz is high, but at the same time, the imaginary part μ ″ is also high and the performance coefficient Q is greatly reduced.

  Further, in the Fe—Si based magnetic sheet shown in FIG. 15, the imaginary part μ ″ of the complex relative permeability at 13.56 MHz is low, but the real part μ ′ is also low.

On the other hand, according to the magnetic sheet of this example shown in FIG. 13, it was found that both the real part μ ′ of the complex relative permeability at 13.56 MHz and the performance coefficient Q can be increased. In this example, it was found that the real part μ ′ ^{(13.56 MHz)} of the complex relative permeability can be about 60 and the performance coefficient Q can be about 12.

  Next, a plurality of Fe-based soft magnetic alloy powders shown in Table 3 below are manufactured by a water atomization method, and each Fe-based soft magnetic powder is flattened, and then the flat powder is converted into a matrix material (chlorinated polyethylene). And kneaded to form a magnetic sheet.

The composition of the Fe-based soft magnetic alloy powder of each sample shown in Table 3 was Fe _{70.5 at%} Si _{13.5 at%} Nb _{3 at%} Cu 1 _at% B _{9 at%} Cr _{3 at%} . Sample No. 1-3, flat processed powder (flat Fe-based soft magnetic alloy powder) was classified at 38 μm or less. 10-15, the flat processed powder is classified by 38 μm or more. About 4-9, the flat processing powder was not classified. In addition, the processing time was 20 hours for flat processing of the original powder. Flattening was performed using a ball mill. The average particle size (D50) of the flat powder of each sample is shown in Table 3 . The average particle size of the alloy powder is a 50% cumulative particle size (D50), measured with a particle size distribution meter (Microtrac MT3000 from Nikkiso).

  16A is an SEM photograph of flat powder classified at 38 μm or less, FIG. 16B is an SEM photograph of flat powder without classification, and FIG. 16C is an image of flat powder classified at 38 μm or more. It is a SEM photograph.

Subsequently, the flat powder content was adjusted to about 50% by volume to form a sheet, and the heat treatment shown in Table 3 was performed. The crystallization start temperature (Tx1) of the bcc phase of the flat powder used in this experiment was 538 ° C., and the crystallization start temperature (Tx2) of the second crystal phase was 699 ° C. (Example 9 in Table 1). See). Therefore, the heat treatment temperatures shown in Table 3 were all higher than Tx1 and lower than Tx2.

The magnetic tote was molded by the doctor blade method, and was pressed under the conditions of 250 kg / cm ² , 100 ° C. and 10 min.

Table 3 shows the average density (g / cm ³ ) of each magnetic sheet.
The sheet thickness of each magnetic sheet was generally in the range of 90 μm to 100 μm.

Then, the real part μ ′, the imaginary part μ ″ and the performance coefficient Q of the complex relative permeability of the flat powder in each magnetic sheet were determined. The real part μ ′ (13.56 MHz) and the imaginary part μ ″ ( 13.56 MHz) was measured using an impedance analyzer. The performance factor Q (13.56 MHz) can be obtained by μ ′ (13.56 MHz) / μ ″ (13.56 MHz). The result is shown in the “Measured Value” column of Table 3 .

Further, as shown in Table 3 , since the average density of the flat powder in each magnetic sheet varies among the samples, the average density is unified to 3.0 (g / cm ³ ), and the complex relative permeability is determined from the actually measured value. The real part μ ′ and the imaginary part μ ″ were calculated. In the column “Density d = 3.0” in Table 3 , the real part of the complex relative permeability calculated with an average density of 3.0 (g / cm ³ ). μ ′ and imaginary part μ ″ are shown. The performance coefficient Q when the average density was 3.0 (g / cm ³ ) was the same as the actually measured value.

  The real part μ ′ and the performance coefficient Q of the complex relative permeability shown in FIGS. 17 and 18 are both calculated by unifying the average density to 3.0 (g / cm 3).

  FIG. 17 shows the relationship between the real part μ ′ of the complex relative permeability and the performance coefficient Q in each sample. As shown in FIG. 17, it was found that the larger the average particle diameter (D50) of the flat powder of each sample, the easier it is to adjust so that both the real part μ ′ of the complex relative permeability and the performance coefficient Q increase. .

  Then, when the performance coefficient Q is about 20 from the experimental results of FIG. 17, when the average particle diameter (D50) of the alloy powder is about 30 μm or more as shown in FIG. 18, the real part μ ′ of the complex relative permeability is It was found that when the average particle size (D50) of the alloy powder was about 60 μm or more, the real part μ ′ of the complex relative permeability could be adjusted to 60 or more. Further, it was found that setting the average particle size (D50) of the alloy powder to about 63 μm or more is preferable because the average particle size (D50) of the alloy powder can be easily adjusted to about 60 μm or more.

  In this embodiment, the characteristic range in which the real part μ ′ of the complex relative permeability is 50 or more and the performance coefficient Q is 20 or more is set to a preferable range, and the real part μ ′ of the complex relative permeability is 60 or more. In addition, the characteristic range in which the performance coefficient Q is 20 or more is set to a more preferable range (FIGS. 17 and 18 are lightly colored in a more preferable range).

  Further, FIG. 17 shows a magnetic sheet using an Fe—Si alloy powder, a magnetic sheet using an Fe-based amorphous alloy powder, and a magnetic sheet using an Fe—Si—Al alloy powder (Sendust (registered trademark)). The relationship between the real part μ ′ of the complex relative permeability and the performance coefficient Q is shown (both are comparative examples). The content of the Fe—Si alloy powder, Fe-based amorphous alloy powder, and Fe—Si—Al alloy powder was about 50% by volume, and chlorinated polyethylene was used as the matrix material. Moreover, the sheet thickness of each comparative example was about 90-110 micrometers.

  As shown in FIG. 17, in the magnetic sheet using the Fe—Si alloy powder and the magnetic sheet using the Fe-based amorphous alloy powder, the performance coefficient Q can be increased, but the real part of the complex relative permeability is increased. μ´ became smaller. In addition, in the magnetic sheet using Fe—Si—Al alloy powder (Sendust; registered trademark), the real part μ ′ of the complex relative permeability can be increased, but the performance coefficient Q is decreased.

  On the other hand, according to the present embodiment, as shown in FIGS. 17 and 18, it is possible to adjust both the real part μ ′ of the complex relative permeability and the performance coefficient Q to be large. In particular, by setting the average particle size (D50) of the flat powder to 30 μm or more, preferably 60 μm or more, more preferably 63 μm or more, the real part μ ′ of the complex relative permeability of 50 or more, preferably 60 or more, and It has been found that a performance factor Q of 20 or more is easily obtained.

  There is a limit to increasing the average particle size (D50) of the flat powder, and the upper limit of the average particle size (D50) of the alloy powder is set to 100 μm.

Next, the heat treatment temperature for each sample in Table 3 will be considered. In Table 3, a sample in which the real part μ ′ (density d = 3.0) of the complex relative permeability is 50 or more and the performance coefficient Q (actual measurement value) is 20 or more is No. 7, 8, 12-15. As shown in Table 3, the heat treatment temperature of these samples was 633 ° C to 642 ° C. Since the flat powder used in each sample _{(Fe 70.5at% Si 13.5at% Nb} 3at% Cu 1at% B 9at% Cr 3at%) crystallization start temperature of the second crystal phase of (Tx2) is a 699 ° C., The heat treatment temperature is set to a lower temperature in the range of about 55 ° C. to 70 ° C. than Tx2, preferably in the range of 57 ° C. to 70 ° C., more preferably in the range of 60 ° C. to 66 ° C. It has been found that the real part μ ′ of the complex relative permeability can be set to 50 or more, preferably 60 or more, and the performance coefficient Q can be set to 20 or more by setting the temperature to a low temperature.
Next, the magnetic sheet was produced using the sample used for experiment of FIG.7 (j)-(m).

In the experiment, sample Nos. ₅ and 7 consisting of Fe _{71.5 at%} Si _{13.5 at%} Nb ₃ Cu ₁ B ₉ Cr ₂ shown in Table 4 were used. 16 to 22 and sample Nos. Having the same composition as in Example 9. 23-30 respectively, the processing time shown in Table 4 in machine bead mill, flattened working was further subjected to heat treatment for 90 minutes at a predetermined temperature shown in Table 4.

  Subsequently, a coupling agent was coated on each sample. In addition, Eraslene 402NA (Showa Denko) (chlorinated polyethylene) was used as a matrix material (resin) for each sample. Here, in each sample, the filling rate of the magnetic powder was adjusted to be about 50% by volume.

  Then, the magnetic powder and the matrix material were kneaded. The magnetic powder and the matrix material were kneaded using Mazerustar (KK-V, Kurabo Industries Co., Ltd.) for 24 minutes to form a mixed material.

A magnetic sheet was formed from the mixed materials of these samples at the plate thicknesses shown in Table 4 using the doctor blade method. During the forming process, press working was performed under the conditions of 100 ° C., 15 minutes, 250 kg / cm ² .

  The density was obtained by punching a sheet sample into a circle having an outer diameter of 10 mm, obtaining the volume from the shape dimension, and dividing the mass by the volume.

Table 4 shows the bcc phase (2θ = 52.72-52.76 °), compound phase (1), (2) (compound phase (1) is 2θ = 51.51-51.64 °, compound in each sample. phase (2) is the value of 2 [Theta] of 2θ = 50.68-50.76 °), the peak of the peak intensity of each compound phase (1) (2) to the peak intensity of the bcc-phase (I ₁₎ (I ₂₎ The intensity ratio ((I ₂ / I ₁ ) × 100) (%) is shown.

  As shown in Table 4, when looking at the characteristics of the magnetic sheet at 13.56 MHz, the Q value is 10 or less at 595 ° C., but 15 or more in the heat treatment at 605 ° C. or more where precipitation of the compound phase is observed. It was found to show a Q value of. It can also be seen that if the annealing temperature is too high, the peak around 2θ = 51.5 ° becomes clear and the precipitation of the compound phase increases. Thus, when the precipitation of the compound phase becomes too large, μ ′ decreases, which is not preferable. For example, in annealing at 635 ° C. or higher, μ ′ tends to be 15 or less.

Next, Fe _{68.5 at%} Si _{13.5 at%} Nb ₃ B _{9 at%} Cu 1 _at% Cr _{3 at%} Ni _{2 at%} magnetic powder (Table 5 No. 31-39), Fe _{73.5 at%} Si _{13.5 at%} Nb _{3 at%} B _{8 at} Magnetic powder (No. 40 to 45 in Table 5) of _% P _1at% Cu 1at _% was produced.

  Each sample shown in Table 5 was flattened with a processing machine bead mill for the processing time shown in Table 5 and further subjected to heat treatment at a predetermined temperature and time shown in Table 5.

  Subsequently, a coupling agent was coated on each sample. In addition, Eraslene 402NA (Showa Denko) (chlorinated polyethylene) was used as a matrix material (resin) for each sample. Here, the filling rate of the magnetic powder in each sample is shown in Table 5.

  Then, the magnetic powder and the matrix material were kneaded. The magnetic powder and the matrix material were kneaded using Mazerustar (KK-V, Kurabo Industries Co., Ltd.) for 24 minutes to form a mixed material.

  A magnetic sheet was formed from the mixed materials of these samples with the plate thicknesses shown in Table 5 using a doctor blade method. The press working at the time of molding is shown in the “HP” column of Table 5.

  The density was obtained by punching a sheet sample into a circle having an outer diameter of 10 mm, obtaining the volume from the shape dimension, and dividing the mass by the volume.

Table 5 shows the bcc phase (2θ = 52.72-52.76 °), compound phase (1), (2) (compound phase (1) is 2θ = 51.51-51.64 °, compound in each sample. phase (2) is the value of 2 [Theta] of 2θ = 50.68-50.76 °), the peak of the peak intensity of each compound phase (1) (2) to the peak intensity of the bcc-phase (I ₁₎ (I ₂₎ The intensity ratio ((I ₂ / I ₁ ) × 100) (%) is shown.

  As shown in Table 5, when looking at the characteristics of the magnetic sheet at 13.56 MHz, the Q value tends to be 10 or less at 600 ° C., but a high Q value is exhibited in heat treatment at 625 ° C. or more. It was. On the other hand, if the annealing temperature is too high, the precipitation of the compound phase increases and μ ′ decreases, which is not preferable.

As shown in the above experimental results, in order to realize good characteristics, it is necessary to appropriately adjust the peak intensity ratio (I ₂ / I ₁ ) between the second crystal phase (compound phase) and the bcc phase. The peak intensity ratio (I ₂ / I ₁ ) is at least 0.02 and 0.15 (2% to 15%), preferably 0.02 to 0.08 (2 to 8%). I found that it was good. Even if the peak intensity ratio (I ₂ / I ₁ ) is too large, the decrease in μ ′ becomes severe, so 0.08 (8%) or less is preferable. Here, the precipitation peak intensity I ₂ of the compound phase (second crystal phase) is about 2θ = 50.6 °, the presence of which can be confirmed after heat treatment at a relatively low temperature, and the precipitation peak of the bcc phase is the strongest. Calculation was performed using a peak around 2θ = 52.7 ° that appears.

DESCRIPTION OF SYMBOLS 1 RFID device 2 Antenna circuit 3 Metal member 4 Magnetic sheet 10 Lead dryer

Claims (11)

Fe-based soft magnetic alloy powder composed of a structure having at least a bcc phase and having a composition in which Tx1 / Tm (end) is 0.5 or more in terms of K ,
The Tx1 is at DSC curve shows the crystallization starting temperature of the bcc-phase, Tm (end The), the temperature of the end of the endothermic curve (the temperature at which the heat flow returns from an endothermic peak showing the melting point Tm to baseline) It is intended to indicate the,
Composition formula is represented by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is B, P, at least any one of a C, Y is, Nb, at least one of Mo 1 The seed, Q, is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at%, 1 at% ≦ c ≦ 6 at%, 0 at% ≦ d. ≦ 5 at%, 0 at% ≦ e ≦ 5 at%,
The structure is composed of a multiphase structure having the bcc phase and a second crystal phase having an X-ray diffraction peak different from the bcc phase;
Wherein the bcc phase of the peak intensity (I _1), the peak intensity of the second crystalline phase (I ₂₎ the peak intensity of the ratio (I ₂ / I ₁₎ is 0.02 to 0.15 Fe-based soft magnetic alloy powder. The composition ratio of Si a is, Fe-based soft magnetic alloy powder according to claim 1, wherein at least 3at%. The Fe-based soft magnetic alloy powder according to claim 1 or 2, wherein the peak intensity ratio (I ₂ / I ₁ ) is 0.02 or more and 0.08 or less. The Fe-based soft magnetic alloy powder according to any one of claims 1 to 3 , wherein an average crystal grain size of the bcc phase is 50 nm or less. The Fe-based soft magnetic alloy powder according to any one of claims 1 to 4 , wherein the Fe-based soft magnetic alloy powder is flattened. The average particle size of F e based soft magnetic alloy powder, Fe-based soft magnetic alloy powder according to claim 5, wherein in the range of 30 .mu.m to 100 .mu.m. The Fe-based soft magnetic alloy powder according to claim 6 , wherein the alloy powder has an average particle size of 60 μm or more. A magnetic sheet comprising a matrix material and a flat powder formed of the Fe-based soft magnetic alloy powder according to any one of claims 5 to 7 . An Fe-based soft magnetic alloy powder mainly composed of an amorphous single phase or an amorphous phase is prepared by an atomizing method from an alloy having a composition in which Tx1 / Tm (end) is 0.5 or more in terms of K,
Tx1 indicates the crystallization start temperature of the bcc phase in the DSC curve, and Tm (end) is the temperature at the end of the endothermic curve (temperature when the heat flow returns from the endothermic peak indicating the melting point Tm to the baseline). are shown the composition formula is represented by _{Fe 100-abcde Si a X b} Y c Cr d Q e, X is B, P, at least any one of a C, Y is, Nb, at least one of Mo Any one of them, Q is at least one of Co, Ni, Cu, and Al, and 0 at% ≦ a ≦ 21 at%, 3 at% ≦ b ≦ 15 at%, 1 at% ≦ c ≦ 6 at%, 0 at % ≦ d ≦ 5 at%, 0 at% ≦ e ≦ 5 at%,
Further heat treatment is performed to precipitate a bcc phase and a second crystal phase having an X-ray diffraction peak different from the bcc phase ,
The heat treatment temperature is set to a temperature higher than the crystallization start temperature (Tx1) of the bcc phase and lower than 100 ° C. than the crystallization start temperature (Tx2) of the second crystal phase. Method for producing magnetic alloy powder. The pre-Symbol heat treatment temperature, the second than the crystalline phase of the crystallization starting temperature (Tx2), the method of producing Fe-base soft magnetic alloy powder according to claim 9 wherein the set to a low temperature within the range of 55 ° C. to 70 ° C. . 11. The Fe-based soft magnetic alloy powder according to claim 10, wherein the Fe-based soft magnetic alloy powder is flattened, and at this time, an average particle diameter of the alloy powder is in a range of 30 μm to 100 μm, and subsequently the heat treatment is performed. Production method.

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