Alloy

Abstract

This alloy contains Fe and B, is provided with an amorphous phase (10) and a plurality of alpha-Fe crystal phases (12) formed in the amorphous phase (10), and has an average Fe concentration of 79 at% or more in the entire alloy, and a crystallinity of 0.3-20% as measured by X-ray diffraction.

Description

Technical Field

[0001] The present invention relates to an alloy, for example, an alloy containing an Fe-based nanocrystalline soft magnetic material. Background Art

[0002] Nanocrystalline alloys have multiple nanoscale crystalline phases (nanocrystalline phases) formed within an amorphous phase. As soft magnetic materials, Fe-Si-B-Nb-Cu alloys and Fe-Cu-P-B-Si alloys are known (for example, Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2021 / 132272 Summary of the Invention

[0006] Although the Fe-Cu-P-B-Si alloy has a higher saturation magnetic flux density than the Fe-Si-B-Nb-Cu alloy, its iron loss is also greater than that of the Fe-Si-B-Nb-Cu alloy.

[0007] The present invention has been completed in view of the above problems, and an object thereof is to provide an alloy having a high saturation magnetic flux density and a small iron loss.

[0008] The present invention is an alloy containing Fe and B, having an amorphous phase and a plurality of α-Fe crystalline phases formed within the amorphous phase, the average Fe concentration in the entire alloy being 79 atomic% or more, and the crystallinity measured by X-ray diffraction being 0.3% to 20%.

[0009] It may be configured as follows: in the above configuration, the average Fe concentration in the entire alloy is 79.0 atomic% to 86.0 atomic%, the average B concentration in the entire alloy is 5.0 atomic% to 14.0 atomic%, the average Si concentration in the entire alloy is 0.0 atomic% to 8.0 atomic%, the average P concentration in the entire alloy is 0.0 atomic% to 8.0 atomic%, the average C concentration in the entire alloy is 0.0 atomic% to 5.0 atomic%, and the average Cu concentration in the entire alloy is 0.0 atomic% to 1.4 atomic%.

[0010] It may be configured as follows: in the above configuration, the average impurity concentration in the entire alloy of impurities other than Fe, Cu, P, B, Si, and C is 0 atomic% to 0.3 atomic%, and the sum of the average Fe concentration, the average Cu concentration, the average P concentration, the average B concentration, the average Si concentration, the average C concentration, and the average impurity concentration is 100.0 atomic%.

[0011] It may be configured as follows: in the above configuration, the average Fe concentration of the entire alloy is 79.0 atomic% to 86.0 atomic%, the average B concentration of the entire alloy is 5.0 atomic% to 14.0 atomic%, the average Si concentration of the entire alloy is 0.0 atomic% to 8.0 atomic%, the average P concentration of the entire alloy is 1.0 atomic% to 8.0 atomic%, the average C concentration of the entire alloy is 0.0 atomic% to 5.0 atomic%, and the average Cu concentration of the entire alloy is 0.4 atomic% to 1.4 atomic%.

[0012] It may be configured as follows: in the above configuration, the ratio of the above average Cu concentration to the above average P concentration is 0.08 to 0.8.

[0013] It may be configured as follows: in the above configuration, the average impurity concentration of the entire alloy in the impurities other than Fe, Cu, P, B, Si, and C is 0 atomic% to 0.3 atomic%, and the sum of the above average Fe concentration, the above average Cu concentration, the above average P concentration, the above average B concentration, the above average Si concentration, the above average C concentration, and the above average impurity concentration is 100.0 atomic%.

[0014] It may be configured as follows: in the above configuration, the resistivity of the above alloy is 0.65 times or more of the resistivity of the alloy with a crystallinity of 0%.

[0015] It may be configured as follows: in the above configuration, the crystallinity is 0.5% to 8%.

[0016] It may be configured as follows: in the above configuration, the above alloy is in powder form or strip form.

[0017] According to the present invention, an alloy with a high saturation magnetic flux density and low iron loss can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 (a) to (c) of are diagrams showing the powder, thin strip, and magnetic component of Embodiment 1.

[0019] Figure 2 is a diagram showing the temperature change during the transportation of samples PA02, PA03, and PA06.

[0020] Figure 3 is a diagram showing the correlation between the crystallinity evaluated by the X-ray diffraction (XRD) method and the crystallinity evaluated by the differential scanning calorimetry (DSC) method.

[0021] Figure 4Figures (a) and (b) are the transmission electron microscope (TEM) image and the selected area electron diffraction (SAED) image of samples PA01 and PA06, respectively.

[0022] Figure 5 Figures (a) and (b) are the transmission electron microscope image and the selected area electron diffraction image of samples PA03 and PA02, respectively.

[0023] Figure 6 Figure (a) is a graph showing the resistivity with respect to the XRD crystallinity. Figure 6 Figure (b) is a graph showing the iron loss W10 / 10k with respect to the XRD crystallinity at a maximum applied magnetic field Bm = 1T and a frequency f = 10kHz.

[0024] Figure 7 Figure (a) is a graph showing the saturation magnetic flux density Bs with respect to the XRD crystallinity. Figure 7 Figure (b) is a graph showing the coercive force Hc with respect to the XRD crystallinity.

[0025] Figure 8 is a graph showing the normalized resistivity with respect to the XRD crystallinity of samples G4, G12, FeB, and AMH1.

[0026] Figure 9 Figures (a) and (b) are graphs showing the normalized W10 / 10k with respect to the XRD crystallinity. Detailed Description of the Invention

[0027] The Fe—Si—B—Nb—Cu alloy can achieve high magnetic permeability and low iron loss, and has good soft magnetic properties. However, the saturation magnetic flux density Bs is about 1.23T. Therefore, if this alloy is applied to electronic components, there is a disadvantage that the applied components and devices become large. On the other hand, although the Fe—Cu—P—B—Si alloy has a high saturation magnetic flux density, it has a large iron loss. Therefore, it is difficult to use the Fe—Cu—P—B—Si alloy in high-frequency electronic components. In particular, in recent years, with the development of power semiconductors, the miniaturization and high power density of power control devices have been promoted. As a result, in high-frequency applications such as several kHz to 10MHz, electronic components with smaller losses (especially small iron loss) are required. In the Fe—Cu—P—B—Si alloy, generally the crystallinity is 40% to 50%. At this crystallinity, although the saturation magnetic flux density of the alloy can be increased, the iron loss is large.

[0028] The iron loss Pe is generally regarded as the sum of the hysteresis loss and the eddy current loss. The eddy current loss is represented by Equation (1).

[0029] [Number 1]

[0030]

[0031] B is the magnetic flux density, f is the frequency, d is the thickness of the alloy, ρ is the resistivity, and C is a constant. According to Number 1, if the frequency becomes higher, the iron loss becomes larger. Therefore, in electronic components for high-frequency applications, it is necessary to further suppress the iron loss generated by eddy currents. If the resistivity becomes lower, the eddy current loss increases. Therefore, in order to suppress the iron loss, it is necessary to increase the resistivity. In the nanocrystalline alloy, the resistivity of the crystalline phase of iron (α-Fe) with a BCC (Body-Centered Cubic) structure is low. Therefore, it is considered that if the crystallinity in the alloy decreases, the resistivity increases and the iron loss is suppressed.

[0032] The manufacturing methods of the amorphous alloy and the nanocrystalline alloy will be described. First, a metal melt obtained by melting a mixture of materials is rapidly cooled to form an amorphous alloy (precursor alloy). The amorphous alloy is almost an amorphous phase and hardly contains a crystalline phase. The amorphous alloy may contain a trace amount of a crystalline phase depending on the conditions of rapid cooling of the metal melt. Hereinafter, the amorphous alloy is heat-treated. The amorphous alloy is heated to a temperature higher than the temperature at which the crystalline phase of α-Fe starts to form. Then, the alloy is cooled, whereby a part of the amorphous alloy becomes a crystalline phase.

[0033] [Embodiment 1]

[0034] The alloy of Embodiment 1 contains Fe (iron) and B (boron), and has an amorphous phase and a plurality of α-Fe crystalline phases formed in the amorphous phase. The crystallinity measured by the X-ray diffraction method is 0.3% to 20%. Thereby, the iron loss can be suppressed. In addition, the alloy preferably contains Fe (iron), Si (silicon), B (boron), P (phosphorus), and Cu (copper). Thereby, the saturation magnetic flux density can be increased and the iron loss can be suppressed.

[0035] [Crystallinity and Resistivity]

[0036] The crystallinity is measured by X-ray diffraction (XRD: X-Ray Diffraction). The XRD crystallinity can be measured as follows. As the X-ray source, for example, a Cu tube target or a Cr (chromium) tube target is used. When performing XRD measurement on an amorphous alloy (precursor alloy), a broad peak from the amorphous (non-crystalline) is observed around 2θ = 45° for a Cu tube target, and a broad peak from the amorphous (non-crystalline) is observed around 2θ = 69° for a Cr tube target. In the case of a crystallized sample, a (110) diffraction peak from BCC-Fe is observed around 2θ = 45° for a Cu tube target, and a (110) diffraction peak from BCC-Fe is observed around 2θ = 69° for a Cr tube target. The crystallinity can be obtained by finding the ratio of the broad diffraction intensity based on the amorphous to the sharp diffraction intensity based on the crystal. In the calculation of the integrated intensity based on diffraction, fitting using a peak shape function is performed. The peak shape function can be arbitrarily selected from a Gaussian function, a Lorentz function, a pseudo-Voigt function, a Pearson VII function, etc. The parameters of the peak shape function are refined using the least squares method to derive the integrated intensity of the peak. If the integrated intensity of the (110) diffraction peak is set as Ic and the integrated intensity of the broad peak from the amorphous is set as Ia, the crystallinity is derived in the form of Ic / (Ic + Ia).

[0037] The crystallinity can be measured by differential scanning calorimetry (DSC: Differential scanning calorimetry) and converted to the crystallinity measured by X-ray diffraction method. In the DSC method, when the temperature of the alloy is scanned from 200 °C to 600 °C at 40 °C per minute, two exothermic peaks are observed. The peak around 400 °C is an exothermic peak due to the precipitation of BCC-Fe, and the peak around 500 °C is an exothermic peak due to the precipitation of boron compounds such as iron boride. Here, the heat quantity based on BCC-Fe around 400 °C is set as ΔH1. When the crystallized sample is measured by DSC, ΔH1 decreases compared to ΔH1 of the amorphous alloy (precursor alloy). By obtaining the ratio of ΔH1 of the amorphous alloy (precursor alloy) to ΔH1 of the crystallized sample, the remaining amount of crystallizable BCC-Fe can be known. The crystallinity is derived in the form of 1 - ΔH1 (crystallized alloy) / ΔH1 (amorphous alloy). For example, when the crystallinity measured by differential scanning calorimetry is enlarged by 0.45 times, it can be converted to the crystallinity measured by X-ray diffraction method.

[0038] When the crystallinity is 0%, the vast majority of the alloy is in the amorphous phase, with relatively high iron loss and relatively low saturation magnetic flux density. If the crystallinity is greater than 20%, the iron loss is almost the same as that when the crystallinity is 0%. If the crystallinity is greater than 0%, the iron loss is suppressed. The iron loss of an alloy with a crystallinity of 0.3% or more is less than that of an alloy with a crystallinity of 0%. When the crystallinity is 0.5% or more, the iron loss further decreases. When the crystallinity is in the range of 0.5% to 6%, the iron loss is small and almost the same value. If the iron loss is 8%, the iron loss slightly increases. If the crystallinity is greater than 20%, the iron loss is almost the same as that when the crystallinity is 0%.

[0039] The resistivity of the alloy is measured by the four-probe method of JIS (Japanese Industrial Standards) K7194. The resistivity of the alloy decreases as the crystallinity increases. When the crystallinity is 0.3% compared to when the crystallinity is 0%, the resistivity is about 0.88 times that of the resistivity when the crystallinity is 0%. When the crystallinity is 5%, the resistivity is about 0.82 times that of the resistivity when the crystallinity is 0%. When the crystallinity is 18%, the resistivity is about 0.68 times that of the resistivity when the crystallinity is 0%. Thus, as the crystallinity increases, the resistivity decreases and the iron loss increases. In summary, the resistivity of the alloy is preferably 0.65 times or more, more preferably 0.7 times or more, and further preferably 0.8 times or more of the resistivity of the alloy with a crystallinity of 0%. When the resistivity is high, the crystallinity is almost 0%. Therefore, the resistivity of the alloy is preferably 0.95 times or less, more preferably 0.9 times or less of the resistivity of the alloy with a crystallinity of 0%.

[0040] In summary, the crystallinity is 0.3% or more, preferably 0.5% or more, more preferably 1% or more, and further preferably 2% or more. The crystallinity is 20% or less, preferably 18% or less, more preferably 10% or less, and further preferably 8% or less. The resistivity is preferably 0.65 times or more, more preferably 0.8 times or more, and further preferably 0.85 times or more of the resistivity of the alloy with the same composition and a crystallinity of 0%.

[0041] [Composition]

[0042] The alloy of Embodiment 1 contains Fe and B, and may contain Si, P, and Cu. Sometimes C (carbon) is contained intentionally or unintentionally. Sometimes impurity elements other than Fe, Si, B, P, Cu, and C are contained unintentionally. The impurities are, for example, at least one element among Ti (titanium), Al (aluminum), Zr (zirconium), Hf (hafnium), Nb (neodymium), Ta (tantalum), Mo (molybdenum), W (tungsten), Cr (chromium), V (vanadium), Co (cobalt), Ni (nickel), Mn (manganese), Ag (silver), Zn (zinc), Sn (tin), Pb (lead), As (arsenic), Sb (antimony), Bi (bismuth), S (sulfur), N (nitrogen), O (oxygen), and rare earth elements.

[0043] The average Fe concentration, Si concentration, B concentration, P concentration, Cu concentration, C concentration, and impurity concentration in the entire alloy are denoted as CFe, CSi, CB, CP, CCu, CC, and CI, respectively. The sum of CFe, CSi, CB, CP, CCu, CC, and CI is 100.0 atomic %. CFe, CSi, CB, CP, CCu, CC, and CI correspond to the chemical compositions of the amorphous alloy and the nanocrystalline alloy. That is, when the composition of the entire alloy is denoted as Fe a B b Si c P x C y Cu z CFe, CSi, CB, CP, CCu, and CC correspond to a, c, b, x, z, and y, respectively. The average concentration of each element in the entire alloy can be measured by using the following method over a range where the crystalline phase is large enough. CSi, CB, CP, and CCu are measured by emission spectrometry (ICP: Inductively Coupled Plasma). CC is measured by combustion method. CFe is calculated as the balance of CSi, CB, CP, CCu, and CC. When the presence of impurities can be confirmed by emission spectrometry, CI is measured using the method corresponding to the detected element.

[0044] From the viewpoint of increasing the saturation magnetic flux density, CFe is 79.0 atomic % or more, preferably 80.0 atomic % or more, and more preferably 81.0 atomic % or more. By increasing the concentration of metalloids (B, P, C, and Si), the amorphous phase can be more stably formed between the crystalline phases. Therefore, CFe is preferably 86.0 atomic % or less, and more preferably 85.0 atomic % or less. In addition, when an amorphous alloy ribbon is produced by quenching a molten metal obtained by melting a material mixture, if CFe is greater than 86.0 atomic %, a stable amorphous alloy cannot be obtained. From this viewpoint, CFe is also preferably 86.0 atomic % or less.

[0045] If CB is high, the amorphous phase can be stably formed. Therefore, CB is preferably 5.0 atomic % or more, more preferably 6.0 atomic % or more, and further preferably 7.0 atomic % or more. In order to increase CB and make CFe 79.0 atomic % or more, CP is reduced. If CP becomes too low, the coercive force becomes high. In addition, if CB becomes high, the formation temperature of an undesirable compound sometimes decreases, inhibiting the formation of a homogeneous nanocrystalline phase and deteriorating the magnetic properties. Therefore, CB is preferably 14.0 atomic % or less, more preferably 13.0 atomic % or less, further preferably 12.0 atomic % or less, and further preferably 11.0 atomic % or less.

[0046] The alloy may not contain Si (i.e., CSi only needs to be 0.0 atomic % or more). If CSi is increased, the ability to form an amorphous phase is enhanced, making the production of amorphous alloys by rapid cooling of the molten metal stable. In addition, the temperature at which the crystalline phase of the compound starts to form becomes higher, and the nanocrystalline phase can be stably formed. Therefore, in order to increase this temperature, CSi is preferably greater than 0.0 atomic %, more preferably 0.2 atomic % or more, and still more preferably 0.4 atomic % or more. In order to increase CSi and make CFe 79.0 atomic % or more, CP will decrease. If CP becomes too low, the coercive force becomes high. Therefore, CSi is preferably 8.0 atomic % or less, more preferably 7.0 atomic % or less, and still more preferably 6.0 atomic % or less.

[0047] The alloy may not contain P (i.e., CP only needs to be 0.0 atomic % or more). If CP is relatively high, the crystalline phase becomes smaller and the coercive force decreases. Therefore, CP is preferably 1.0 atomic % or more, more preferably 2.0 atomic % or more, and still more preferably 3.0 atomic % or more. In order to increase CP and make CFe 79.0 atomic % or more, CB and CSi will decrease. If CB and CSi become too low, it becomes difficult to stably form an amorphous phase. Therefore, CP is preferably 8.0 atomic % or less, more preferably 7.0 atomic % or less, and still more preferably 6.0 atomic % or less.

[0048] The alloy may not contain Cu (i.e., CCu only needs to be 0.0 atomic % or more). By adding Cu to the alloy, Cu clusters become nucleation sites at the initial stage of the formation of the crystalline phase to form the crystalline phase. Therefore, CCu is preferably 0.4 atomic % or more, more preferably 0.5 atomic % or more, and still more preferably 0.6 atomic % or more. If Cu clusters exist in the crystalline phase and the amorphous phase, they will become obstacles to the movement of magnetic walls. In addition, if Cu is dissolved in the crystalline phase and the amorphous phase, the quantum mechanical interaction between Fe atoms and Cu atoms becomes larger. As a result, the saturation magnetic flux density decreases. From these viewpoints, CCu is preferably 1.4 atomic % or less, more preferably 1.3 atomic % or less, and still more preferably 1.2 atomic % or less.

[0049] If a trace amount of C is added, it is beneficial to the formation of the amorphous alloy. If an excessive amount is added, it will cause embrittlement of the alloy and deterioration of properties. Therefore, CC is 0 atomic % or more, and preferably 5.0 atomic % or less, more preferably 4.0 atomic % or less, and still more preferably 3.0 atomic % or less. It is preferred not to intentionally add impurities. Therefore, CI is 0 atomic % or more, and preferably 0.3 atomic % or less, more preferably 0.2 atomic % or less, and still more preferably 0.1 atomic % or less. The impurity elements are also preferably 0 atomic % to 0.10 atomic %, more preferably 0 atomic % to 0.02 atomic %.

[0050] There is an attractive force between Cu atoms and P atoms. If the alloy composition contains specific ratios of Cu element and P element, a homogeneous Fe crystal can be obtained during the formation of the nanocrystalline phase, and excellent magnetic properties can be achieved. The ratio of CCu to CP (CCu / CP ratio) is preferably 0.8 or less, more preferably 0.7 or less, and further preferably 0.6 or less when considering the oxidation and embrittlement of the composition. The CCu / CP ratio is preferably 0.08 or more, more preferably 0.1 or more.

[0051] The size (particle diameter) of the crystalline phase in the nanocrystalline alloy affects soft magnetic properties such as coercivity. If the size of the crystalline phase is small, the coercivity decreases and the soft magnetic properties improve. Therefore, the average value of the spherical equivalent diameter of the crystalline phase is preferably 50 nm or less, more preferably 30 nm or less, and further preferably 20 nm or less, for example. The average value of the spherical equivalent diameter of the crystalline phase 12 is 5 nm or more, for example.

[0052] [Manufacturing method]

[0053] Hereinafter, the manufacturing method of the nanocrystalline alloy will be described. The manufacturing method of the alloy of the embodiment is not limited to the following method.

[0054] [Manufacturing method of amorphous alloy]

[0055] In the manufacturing of the amorphous alloy, for example, the single-roll method is used. The conditions of the roll diameter and rotation speed of the single-roll method are arbitrary. Since the single-roll method is easy to rapidly cool, it is suitable for manufacturing amorphous alloys. In the manufacturing of the amorphous alloy, methods other than the single-roll method can also be used for the cooling rate of the alloy melted for manufacturing the amorphous alloy. For example, the water atomization method or the atomization method described in Japanese Patent No. 6533352 can be used in the manufacturing of the amorphous alloy.

[0056] [Manufacturing method of nanocrystalline alloy]

[0057] The nanocrystalline alloy is obtained by heat treatment of the amorphous alloy. In the manufacture of the nanocrystalline alloy, the temperature profile during heat treatment affects the nanostructure of the nanocrystalline alloy. For example, during heat treatment, mainly the heating rate, holding temperature, holding time, and cooling rate affect the crystallinity. In particular, the holding temperature most affects the crystallinity. The maximum holding temperature is set to the desired crystallinity. The holding temperature is, for example, 200°C to 450°C. The heating rate from room temperature to the holding temperature is preferably 10°C / minute or more, more preferably 20°C / minute or more. The length of the holding period is preferably a time at which it can be judged that crystallization has been sufficiently carried out. For example, the length of the holding period is preferably 1 second or more, more preferably 5 seconds or more. From the viewpoint of shortening the manufacturing time, the length of the holding period is preferably 1 hour or less. The cooling rate from the maximum holding temperature to room temperature is preferably 0.2°C / second or more. The heating rate, holding temperature, holding time, and cooling rate of the heat treatment can be appropriately selected according to the size of the applied component, etc., to achieve crystallization conditions.

[0058] [Embodiment 2]

[0059] Figure 1 (a) to (c) of FIG. are diagrams showing the powder, ribbon, and magnetic component of Embodiment 1. As Figure 1 shown in (a) of FIG., the powder 20 may contain the alloy of Embodiment 1. The particle size of the powder 20 is evaluated by the median particle size according to the particle size distribution obtained by the laser diffraction / scattering method. The D90 of the powder 20 is, for example, 3 μm to 100 μm, the D50 of the powder 20 is, for example, 2 to 50 μm, and the D10 of the powder 20 is, for example, 0.5 to 20 μm. As Figure 1 shown in (b) of FIG., the ribbon 22 may contain the alloy of the embodiment. The width of the ribbon 22 is, for example, 1 to 500 mm, and the thickness is, for example, 8 to 60 μm. As Figure 1 shown in (a) and (b) of FIG., the alloy may be in powder form or ribbon form. As Figure 1 shown in (c) of FIG., the soft magnetic core 24 may contain the alloy of Embodiment 1. The soft magnetic core 24 is, for example, a molded body obtained by molding a mixture of the powder of Figure 1 (a) of FIG. and a binder material. The binder material is preferably composed of a resin. The molded body may be a magnetic component other than the soft magnetic core 24.

[0060] Example 1

[0061] Samples were prepared as follows.

[0062] [Manufacture of Amorphous Alloy]

[0063] As starting materials for the alloy, reagents such as iron (impurities of 0.01 wt% or less), boron (impurities of less than 0.5 wt%), iron phosphide (impurities of less than 1 wt%), copper (impurities of less than 0.01 wt%), and metallic silicon (impurities of less than 0.00001 wt%) are prepared. During the process of manufacturing the nanocrystalline alloy from the mixture of these reagents, it is confirmed in advance that there is no loss or mixing of elements.

[0064] Prepare 200 g of the mixture so as to achieve the desired chemical composition. Heat the mixture in a crucible under an argon atmosphere to form a homogeneous molten metal. Solidify the molten metal in a copper mold to manufacture an ingot.

[0065] Manufacture an amorphous alloy from the ingot using the single-roll method. Melt 20 g of the ingot in a BN (boron nitride) crucible and discharge it through a quartz nozzle with an opening of 10 mm × 0.3 mm onto a pure copper rotating roll. An amorphous thin strip with a width of 10 mm and a thickness of 25 μm is formed on the rotating roll as the amorphous alloy. The amorphous thin strip is peeled off from the rotating roll by argon gas injection. Using an X-ray diffraction device and the above method, confirm that the amorphous thin strip is an amorphous alloy consisting only of amorphous.

[0066] [Manufacturing device]

[0067] Perform heat treatment on the amorphous alloy. As the heat treatment for forming the nanocrystalline alloy, use the following two devices

[0068] Device A: Roll-to-roll heat treatment furnace

[0069] Device B: Tube furnace

[0070] [Method for measuring crystallinity (XRD crystallinity) based on the XRD method]

[0071] Measuring device: MiniFlex600 manufactured by Rigaku Corporation

[0072] X-ray source: Cu

[0073] 2θ range: 20° to 110°

[0074] 2θ scan step: 0.01°

[0075] Sample size: 10 mm × 70 mm

[0076] Measuring plane: Roll surface

[0077] [Method for measuring crystallinity (DSC crystallinity) based on the DSC method]

[0078] Measuring device: DSC8500 manufactured by PerkinElmer

[0079] Purge gas: Ar

[0080] Sample tray: Pt

[0081] Temperature scanning conditions: After maintaining at 200 °C for 1 minute, heat from 200 °C to 600 °C at a rate of +40 °C / minute

[0082] Sample mass: Approximately 10 mg

[0083] [Method for measuring iron loss]

[0084] Measuring device: Iwasaki Electric Co., Ltd. SY-8219, SY-956

[0085] Primary winding: 40 T

[0086] Secondary winding: 200 T

[0087] Frequency: 10 kHz

[0088] Magnetic flux density: 1.0 T

[0089] Sample size: 10 mm × 70 mm

[0090] [Method for measuring saturation magnetic flux density]

[0091] Measuring device: VSM-P7-15 manufactured by Toei Industry Co., Ltd.

[0092] Applied magnetic field: 955 kA / m

[0093] Sample size: 8 mm × 8 mm

[0094] [Method for measuring coercive force]

[0095] Measuring device: BHS-40 manufactured by Riken Denshi Co., Ltd.

[0096] Applied magnetic field: 2000 A / m

[0097] Sample size: 10 mm × 70 mm

[0098] [Method for measuring resistivity]

[0099] Measuring device: Loresta AX MCP-T370 manufactured by Nitto Seiko Analysis Technology

[0100] Device A is used to fabricate the sample. Table 1 shows the composition of the fabricated alloy in atomic % and mass %.

[0101] [Table 1]

[0102] Fe Si B P Cu C [atomic %] 84.8 0.5 9.4 3.4 0.8 1.2 [mass %] 94.4 0.3 2.0 2.1 1.0 0.3

[0103] As shown in Table 1, the concentrations CFe, CSi, CB, CP, CCu, and CC of Fe, Si, B, P, Cu, and C are 84.8 atomic %, 0.5 atomic %, 9.4 atomic %, 3.4 atomic %, 0.8 atomic %, and 1.2 atomic %, respectively.

[0104] Table 2 is a table showing the production conditions, crystallinity, resistivity, W10 / 10k, coercive force Hc, and saturation magnetic flux density Bs of the produced samples. The "-" in Table 2 indicates that the measurement was not performed. Samples PA01 and AsQ are in the amorphous alloy state and were not heat-treated.

[0105] [Table 2]

[0106]

[0107] In the roll-to-roll heat treatment furnace, a temperature distribution is formed along the direction of transporting the sample in the furnace, and the heat treatment conditions are determined by the heating temperature and the transport speed of the sample. As shown in Table 2, the heating temperatures of samples PA02, PA03, and PA06 are 485 °C, 435 °C, and 425 °C, respectively, and the transport speeds are 1.0 m / minute, 1.5 m / minute, and 2.5 m / minute, respectively. In samples PA06a - PA06l and PA01a - PA01d, the transport speed is 2.5 m / minute, and the heating temperature is not changed.

[0108] Figure 2 is a graph showing the temperature change during the transport of samples PA02, PA03, and PA06. The temperature is the temperature measured by the thermocouple when a thermocouple with a diameter of 0.5 mm is clamped between stainless steel foils and transported in apparatus A. As Figure 2 shown, if the transport speed is fast, the holding period is short, and the heating speed and the cooling speed are fast.

[0109] According to Table 1, the crystallinity mainly depends on the heating temperature. If the heating temperature is high, the crystallinity becomes large. For example, as compared with PA03 and PA06 - e, at the same heating temperature, the crystallinity is almost the same, but the crystallinity of sample PA06 - e with a fast transport speed is slightly larger than that of sample PA03.

[0110] Figure 3 is a graph showing the correlation between the XRD crystallinity and the DSC crystallinity. As Figure 3 shown, the XRD crystallinity and the DSC crystallinity show a good correlation. By expanding the DSC crystallinity by 0.45 times, it can be converted into the XRD crystallinity.

[0111] Figure 4 of (a) - Figure 5(b) are the TEM (Transmission Electron Microscope) images and SAED (Selected Area Electron Diffraction) images in samples PA01, PA06, PA03, and PA02, respectively. The upper right figure in each image is the SAED image. As Figure 4 shown in (a), in the non-heat-treated sample PA01, the TEM image is a generally uniform gray, and no spots caused by crystals can be observed in the SAED image. The gray area in the TEM image is the amorphous phase 10.

[0112] As Figure 4 shown in (b), in sample PA06, black or white crystalline phases 12 can be observed in the gray amorphous phase 10 in the TEM image. Faint spots can be observed in the SAED image. As Figure 5 shown in (a), in sample PA03, compared with sample PA06, more crystalline phases 12 can be observed in the amorphous phase 10 in the TEM image. In the SAED image, stronger spots can be observed compared with sample PA06. As Figure 5 shown in (b), in sample PA02, compared with sample PA02, more crystalline phases 12 can be observed in the amorphous phase 10 in the TEM image. In the SAED image, stronger spots can be observed compared with Figure 5 (a). Thus, the crystallinity of the alloy can be changed according to the heat treatment temperature.

[0113] Figure 6 (a) is a graph showing the resistivity versus the XRD crystallinity, Figure 6 (b) is a graph showing W10 / 10k versus the XRD crystallinity. W10 / 10k on the vertical axis corresponds to the iron loss at a maximum applied magnetic field Bm = 1 T and a frequency f = 10 kHz. The crystallinity on the horizontal axis is represented logarithmically, and the sample with a crystallinity of 0% is plotted as a crystallinity of 0.1%.

[0114] As Figure 6As shown in (a), when the crystallinity is 0.1% or less, the resistivity is approximately 170 μΩ·cm. The value obtained by normalizing the resistivity using the resistivity of almost 0% crystallinity is defined as the normalized resistivity. When the crystallinity is 0.3% to 4%, the resistivity is approximately 150 μΩ·cm, and the normalized resistivity is 150 / 170 = 0.88, which is almost constant. If the crystallinity is 5% and 8%, the resistivity is approximately 140 μΩ·cm, and the normalized resistivity is 140 / 170 = 0.82, which is slightly reduced. If the crystallinity is 18%, the resistivity is approximately 115 μΩ·cm, and the normalized resistivity is 115 / 170 = 0.68, which is lower. The assumed value of the resistivity at 20% crystallinity is approximately 110 μΩ·cm, and the normalized resistivity is 110 / 170 = 0.65. Then, if the crystallinity increases, the resistivity decreases.

[0115] As Figure 6 shown in (b), when the crystallinity is 0.1% or less, W10 / 10k is approximately 170 to 190 W / kg. The value obtained by normalizing W10 / 10k using W10 / 10k = 170 W / kg of almost 0% crystallinity is defined as the normalized W10 / 10k. When the crystallinity is 0.3% and 0.4%, W10 / 10k is 120 to 130 W / kg, and the normalized W10 / 10k is 120 to 130 / 170 = 0.70 to 0.76. When the crystallinity is 0.5% to 5%, W10 / 10k is 80 to 90 W / kg, and the normalized W10 / 10k is 80 to 90 / 170 = 0.47 to 0.53, which is almost constant. If the crystallinity is 8%, W10 / 10k is approximately 110 W / kg, and the normalized W10 / 10k is 110 / 170 = approximately 0.65. If the crystallinity is 18%, W10 / 10k is approximately 145 W / kg, and after normalization, the normalized W10 / 10k is 145 / 170 = approximately 0.85. When the crystallinity is 26% to 28%, W10 / 10k is approximately 170 W / kg, and the normalized W10 / 10k is 170 / 170 = approximately 1, which is almost the same as the alloy with 0% crystallinity. If the crystallinity is 30% or more, W10 / 10k decreases again.

[0116] In summary, near a crystallinity of 0%, almost no crystalline phase is formed, so the iron loss is relatively large. If the crystallinity is 0.3% or more, a crystalline phase is formed, so the iron loss becomes smaller. When the crystallinity is 0.3% - 5%, the resistivity hardly changes and the iron loss hardly changes. If the crystallinity is greater than 5%, the resistivity begins to decrease, so the iron loss begins to increase. If the crystallinity is greater than 10%, the resistivity further decreases and the iron loss increases. If the crystallinity is greater than 20%, the resistivity further decreases and the iron loss is at the same level as that of the amorphous alloy with a crystallinity of 0%. Thus, it is considered that the change in iron loss caused by crystallinity is due to the change in resistivity. It is considered that the sudden decrease in resistivity when the crystallinity is 10% - 20% is affected by the percolation effects. If the crystallinity is greater than 30%, the resistivity further decreases. However, the iron loss is suppressed. It is considered that this is because the saturation magnetic flux density increases as the crystallinity increases.

[0117] Figure 7 (a) of Figure 7 is a graph showing the saturation magnetic flux density Bs with respect to the XRD crystallinity. Figure 7 (b) of Figure 7 is a graph showing the coercive force Hc with respect to the XRD crystallinity. As Figure 7 shown in (a) of Figure 7 , if the crystallinity decreases, the saturation magnetic flux density Bs decreases. However, even when the crystallinity is 0%, the saturation magnetic flux density Bs is 1.6 T, which is also larger than that of the Fe - Si - B - Nb - Cu alloy. As Figure 7 shown in (b) of Figure 7 , the coercive force Hc has a deviation of 1.6 A / m - 5.6 A / m, and the correlation between the crystallinity and the coercive force Hc is small.

[0118] Samples were made using apparatus B. Six 10 mm × 70 mm samples were stacked and placed in a tubular furnace at room temperature. The temperature was raised to the target temperature at a rate of 20 °C per minute. After holding for the holding time at the target temperature, the samples were taken out of the tubular furnace and air-cooled.

[0119] Table 3 is a table showing the composition of the alloys produced in atomic percentages.

[0120] [Table 3]

[0121]

[0122] As shown in Table 3, the composition of Composition A is almost the same as that of Table 1. In Composition B, compared with Composition A, 1.5 atomic% of B is increased, and Fe, P, and C are each reduced by 0.5 atomic%, 0.5 atomic%, and 0.4 atomic% respectively. In Composition C, compared with Composition B, 2.2 atomic% of Si is increased, and Fe, B, and C are each reduced by 1.1 atomic%, 0.7 atomic%, and 0.5 atomic% respectively.

[0123] Tables 4 and 5 are tables showing the composition, production conditions of the produced samples, and the crystallinity and W10 / 10k, coercive force Hc, and saturation magnetic flux density Bs. The samples with an arrival temperature of 25 °C in Tables 4 and 5 were heat-treated.

[0124] [Table 4]

[0125]

[0126] [Table 5]

[0127]

[0128] As shown in Table 4, in the samples of Composition A, if the holding time is set to 60 minutes and the arrival temperature is increased, the crystallinity becomes larger. Compared with the samples with a crystallinity of 0% and 27.7% or more, in the samples with a crystallinity of 1.7% - 2.5%, W10 / 10k is smaller, about 100 W / kg. The saturation magnetic flux density Bs decreases as the crystallinity decreases, and even when the crystallinity is 0%, it is 1.6 T. The coercive force Hc is larger when the crystallinity is 27.7% or more. As above, the trends of W10 / 10k and saturation magnetic flux density Bs with respect to the crystallinity in Samples of Composition A are the same in Tables 2 and 4 with different heat treatment methods.

[0129] When comparing the sample with an arrival temperature of 265 °C and a holding time of 60 minutes with the sample of 12 hours, the crystallinity increases from 2.1% to 3.7% by extending the holding time. The saturation magnetic flux density Bs and W10 / 10k hardly change in the samples with a holding time of 60 minutes and 12 hours.

[0130] As shown in Table 5, in Compositions B and C, when the crystallinity is 2.1 - 2.5%, W10 / 10k is about 100 W / kg. The saturation magnetic flux density Bs decreases as the crystallinity decreases, and even when the crystallinity is 0%, it is 1.53 T. The coercive force Hc is larger when the crystallinity is 23.6% or more. As described above, the trends of W10 / 10k and saturation magnetic flux density Bs with respect to the crystallinity are the same in Compositions A - C with different compositions.

[0131] In summary, if the crystallinity is 0.3% - 20%, the saturation magnetic flux density can be increased and the iron loss can be suppressed regardless of the manufacturing method and composition.

[0132] Example 2

[0133] Samples without Si, P, and Cu were produced as Example 2. The manufacturing method of the amorphous alloy is the same as that of Example 1.

[0134] [Manufacturing Conditions]

[0135] Manufacturing apparatus: Tube furnace

[0136] Holding time: 30 minutes

[0137] Heating rate: 40 °C / second to 70 °C / second

[0138] Vacuum degree: 10 －3 MPa or less

[0139] In the tube furnace set to the target temperature, the sample is sealed and a quartz tube in a vacuum state is inserted. After the holding time, the quartz tube in the tube furnace is taken out.

[0140] [Method for measuring crystallinity (XRD crystallinity) based on XRD method]

[0141] Measuring apparatus: MiniFlex600 manufactured by Rigaku Corporation

[0142] X-ray source: Cr

[0143] 2θ range: 40° to 140°

[0144] 2θ scanning step size: 0.01°

[0145] Sample size: 10 mm × 70 mm

[0146] Measuring surface: Roll surface

[0147] [Method for measuring iron loss]

[0148] Measuring apparatus: SY-8219, SY-956 manufactured by Iwasaki Electric Co., Ltd.

[0149] Primary winding: 40T

[0150] Secondary winding: 35T

[0151] Frequency: 10 kHz

[0152] Magnetic flux density: 1.0T

[0153] Sample size: 10 mm × 70 mm

[0154] [Method for measuring saturation magnetic flux density]

[0155] Measuring apparatus: VSM-P7-15 manufactured by Toei Industry Co., Ltd.

[0156] Applied magnetic field: 955 kA / m

[0157] Sample size: 8 mm × 8 mm

[0158] [Method for measuring coercive force]

[0159] Measuring apparatus: BHS-40 manufactured by Riken Denshi Co., Ltd.

[0160] Applied magnetic field: 2000 A / m

[0161] Sample size: 10 mm × 70 mm

[0162] [Method for measuring resistivity]

[0163] Measuring device: RM3545 manufactured by Hioki Electric Co., Ltd.

[0164] 4-terminal detector: RM9010-2

[0165] Detector interval: 1.5 mm

[0166] Samples were fabricated for 5 compositions. Table 6 is a table showing the compositions and thicknesses of the fabricated alloys.

[0167] [Table 6]

[0168]

[0169] As shown in Table 6, sample G4 contains Fe, Si, B, P, and Cu, corresponding to Example 1. Sample G12 contains Fe, B, P, and Cu and does not contain Si. Sample FeB contains Fe and B and does not contain Si, P, and Cu. Sample AMH1 contains Fe, Si, and B and does not contain P and Cu. Although sample FT contains Nb in addition to Fe, Si, B, P, and Cu, the composition of Fe is 73.5 atomic %, which is low.

[0170] Tables 7 to 11 are tables showing the arrival temperatures, crystallinities, resistivities, W10 / 10k, coercive forces Hc, and saturation magnetic flux densities Bs of the separately fabricated samples G4, G12, FeB, AMH1, and FT. Sample AsQ is in the amorphous alloy state and has not been heat-treated.

[0171] [Table 7]

[0172]

[0173] [Table 8]

[0174]

[0175] [Table 9]

[0176]

[0177] [Table 10]

[0178]

[0179] [Table 11]

[0180]

[0181] According to Tables 8 to 11, the coercive force Hc is 100 A / m or less and is good within the range of XRD crystallinity of 0.3% to 20% in samples G4, G12, FeB, AMH1, and FT. In particular, within the range of XRD crystallinity of 0.3% to 8%, the coercive force Hc is 40 A / m or less and is good.

[0182] In samples G4, G12, FeB, and AMH1, the saturation magnetic flux density Bs is 1.5 T or more and is good. In sample FT, the saturation magnetic flux density is 1.3 T or less, which is low. This is because the Fe composition of sample FT is 73.5 atomic%, which is low.

[0183] Figure 8 It is a graph of the normalized resistivity of samples G4, G12, FeB, and AMH1 with respect to the XRD crystallinity. Figure 9 (a) and (b) of are graphs showing the normalized W10 / 10k with respect to the XRD crystallinity. Figure 9 (b) of is Figure 9 a graph obtained by magnifying the vertical axis of (a) of. The normalized resistivity and the normalized W10 / 10k are normalized with respect to AsQ in each of the samples G4, G12, FeB, and AMH1. The points are the measurement points.

[0184] As Figure 8 shown, in samples G4, G12, FeB, and AMH1, the normalized resistivity is almost 1 when the XRD crystallization rate is 0.1% to 10%. When the XRD crystallization rate is about 30%, the normalized resistivity decreases to about 0.8. Thus, within the range of XRD crystallization rate of 0.3% to 20%, the normalized resistivity is 0.65 or more.

[0185] As Figure 9 (a) and (b) of shown, in samples G4, G12, FeB, and AMH1, when the XRD crystallization rate is 0.1% to 10%, the normalized W10 / 10k is 1 or less. When the XRD crystallization rate is about 30%, the normalized 10 / 10k is greater than 1, and if the XRD crystallization rate becomes larger, the normalized 10 / 10k becomes very large.

[0186] According to Example 2, in sample G12 that does not contain Si, FeB that does not contain Si, P, and Cu, and AMH1 that does not contain P and Cu, the iron loss can be suppressed in the same way as in sample G4 that contains Fe, Si, B, P, and Cu when the XRD crystallinity is 0.3% to 20%. In addition, the saturation magnetic flux density Bs can be increased.

[0187] As described above, the preferred embodiments of the invention have been described in detail. However, the present invention is not limited to the above specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the scope of patent claims.

[0188] Symbol Explanation

[0189] 10 Amorphous Phase

[0190] 12 Crystalline Phase

Claims

1. An alloy containing Fe and B, having an amorphous phase and a plurality of α-Fe crystal phases formed within the amorphous phase, the average Fe concentration of the whole alloy being 79 atomic % or more, and the crystallinity measured by X-ray diffraction method being 0.3% to 20%.

2. The alloy according to claim 1, wherein, The average Fe concentration of the whole alloy is 79.0 atomic % to 86.0 atomic %, the average B concentration of the whole alloy is 5.0 atomic % to 14.0 atomic %, the average Si concentration of the whole alloy is 0.0 atomic % to 8.0 atomic %, the average P concentration of the whole alloy is 0.0 atomic % to 8.0 atomic %, the average C concentration of the whole alloy is 0.0 atomic % to 5.0 atomic %, the average Cu concentration of the whole alloy is 0.0 atomic % to 1.4 atomic %.

3. The alloy according to claim 2, wherein, The average impurity concentration of the whole alloy of impurities other than Fe, Cu, P, B, Si and C is 0 atomic % to 0.3 atomic %, and the sum of the average Fe concentration, the average Cu concentration, the average P concentration, the average B concentration, the average Si concentration, the average C concentration and the average impurity concentration is 100.0 atomic %.

4. The alloy according to claim 1, wherein, The average Fe concentration of the whole alloy is 79.0 atomic % to 86.0 atomic %, the average B concentration of the whole alloy is 5.0 atomic % to 14.0 atomic %, the average Si concentration of the whole alloy is 0.0 atomic % to 8.0 atomic %, the average P concentration of the whole alloy is 1.0 atomic % to 8.0 atomic %, the average C concentration of the whole alloy is 0.0 atomic % to 5.0 atomic %, the average Cu concentration of the whole alloy is 0.4 atomic % to 1.4 atomic %.

5. The alloy according to claim 4, wherein The ratio of the average Cu concentration to the average P concentration is 0.08 to 0.

8.

6. The alloy according to claim 4, wherein, The average impurity concentration of the whole alloy of impurities other than Fe, Cu, P, B, Si and C is 0 atomic % to 0.3 atomic %, and the sum of the average Fe concentration, the average Cu concentration, the average P concentration, the average B concentration, the average Si concentration, the average C concentration and the average impurity concentration is 100.0 atomic %.

7. The alloy according to claim 6, wherein, The resistivity of the alloy is 0.65 times or more of the resistivity of the alloy with a crystallinity of 0%.

8. The alloy according to claim 6, wherein The crystallinity is 0.5% to 8%.

9. The alloy according to any one of claims 1 to 8, wherein The alloy is in powder form or strip form.

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