Soft magnetic alloy powder, magnetic core, magnetic component, and electronic device

Abstract

To provide a soft magnetic alloy powder capable of obtaining a magnetic core excellent in all of magnetic current superposition characteristics, magnetic permeability, and withstand voltage SOLUTION: The soft magnetic powder is represented by a compositional formula (Fe1-pX1p) 100 - (a + b + c + d + e) BaPbSicCdX2e (atomic ratio). The X1 part is one or more kinds selected from Co and Ni, and the X2 part is one or more kinds selected from Ti, Zr, Hf, Nb, Ta, Mo, Cr, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Mn, Sn, As, Sb, Bi, N, Au, Cu, rare earth elements and platinum group elements. 0 ≤ p ≤ 0.5, 2.00 ≤ a ≤ 20.00, 0.00 ≤ b ≤ 14.00, 0.00 ≤ c ≤ 10.00, 0.00 ≤ d ≤ 5.00, 0.00 ≤ e ≤ 3.00, and 70.00 ≤ 100 - (a + b + c + d + e) ≤ 96.00.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a soft magnetic alloy powder, a magnetic core, a magnetic component, and an electronic device. [Background technology]

[0002] Patent Document 1 describes a soft magnetic material that ensures excellent fluidity while reducing material loss. The soft magnetic material is characterized by being made of powder particles with a particle size distribution that has multiple peaks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-36194 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a soft magnetic alloy powder that can provide a magnetic core having good DC bias characteristics, magnetic permeability, and voltage resistance. [Means for solving the problem]

[0005] In order to achieve the above object, the soft magnetic alloy powder of the present invention comprises: Composition formula (Fe 1-p X1 p ) 100-(a+b+c+d+e) B a P b Si c C d X2 e (atomic ratio) A soft magnetic alloy powder, X1 is at least one selected from Co and Ni, and X2 is at least one selected from Ti, Zr, Hf, Nb, Ta, Mo, Cr, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Mn, Sn, As, Sb, Bi, N, Au, Cu, rare earth elements, and platinum group elements; 0≦p≦0.5, 2.00≦a≦20.00, 0.00≦b≦14.00, 0.00≦c≦10.00, 0.00≦d≦5.00, 0.00≦e≦3.00, and 70.00≦100-(a+b+c+d+e)≦96.00 is.

[0006] The volume-based particle size distribution F(x) of the soft magnetic alloy powder is expressed by a plurality of probability density functions f i (x) (i=1, 2, . . . , n) (n≧2), may be expressed by the following formulas (1) to (4): The particle diameter when the volume-based cumulative relative frequency calculated from F(x) is 10% is defined as D10, and the particle diameter when the volume-based cumulative relative frequency is 90% is defined as D90. 0<|exp(μ1)-exp(μ2)| / (D90-D10)≦1.0, 0.1 ≤ σ1 ≤ 1.1, and The relationship 0.01≦σ2≦1.5 may be satisfied.

[0007]

number

[0008]

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[0009]

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[0010]

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[0011] The particle size D50 when the volume-based cumulative relative frequency of the soft magnetic alloy powder is 50% may be 1.0 μm or more and less than 45.0 μm.

[0012] The oxygen content may be 300 ppm or more and 10,000 ppm or less.

[0013] The soft magnetic alloy powder may contain an amorphous material.

[0014] The soft magnetic alloy powder may have a crystallization start temperature Tx and a glass transition temperature Tg, and may have a supercooled liquid region expressed by ΔTx=Tx−Tg.

[0015] The soft magnetic alloy powder may include nanocrystals.

[0016] The magnetic core of the present invention contains the soft magnetic alloy powder described above.

[0017] The magnetic core of the present invention may contain two or more types of powder including the soft magnetic alloy powder described above.

[0018] The magnetic core according to the present invention contains the soft magnetic alloy powder described above.

[0019] A magnetic component according to the present invention contains the soft magnetic alloy powder described above.

[0020] An electronic device according to the present invention includes the soft magnetic alloy powder described above. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a schematic diagram showing the arrangement of spray holes. [Figure 2] 10 is a graph showing the relationship between the water pressure of water sprayed from the spray hole and time. [Figure 3] 10 is a graph of f1(x) in Example 5. [Figure 4] 10 is a graph of f1(x) and f2(x) in Example 21. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described.

[0023] The soft magnetic alloy powder of this embodiment has the composition formula (Fe 1-p X1 p ) 100-(a+b+c+d+e) B a P b Si c C d X2 e A soft magnetic alloy powder represented by (atomic ratio), X1 is at least one selected from Co and Ni, and X2 is at least one selected from Ti, Zr, Hf, Nb, Ta, Mo, Cr, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Mn, Sn, As, Sb, Bi, N, Au, Cu, rare earth elements, and platinum group elements; 0≦p≦0.5, 2.00≦a≦20.00, 0.00≦b≦14.00, 0.00≦c≦10.00, 0.00≦d≦5.00, 0.00≦e≦3.00, and 70.00≦100-(a+b+c+d+e)≦96.00 is.

[0024] By using soft magnetic alloy powder having a composition within the above range, it is possible to obtain a magnetic core having good DC bias characteristics, magnetic permeability and voltage resistance.

[0025] There are no particular limitations on the method for analyzing the composition of the soft magnetic alloy powder. For example, it can be confirmed by ICP analysis. Alternatively, a cross section of a compact containing the soft magnetic alloy powder may be analyzed using SEM-EDS, EPMA, or the like.

[0026] Hereinafter, each component of the soft magnetic alloy powder according to this embodiment will be described in detail.

[0027] X1 is one or more selected from Co and Ni. By using a soft magnetic alloy powder in which 0≦p≦0.5, i.e., a soft magnetic alloy powder in which the Fe content is equal to or greater than the combined content of Co and Ni, a magnetic core with excellent properties can be obtained. Soft magnetic alloy powders in which p exceeds 0.5 have significantly reduced amorphous-forming ability compared to soft magnetic alloy powders in which p is 0.5 or less. As a result, the pressure resistance of magnetic cores using such soft magnetic alloy powders is reduced.

[0028] The B content (a) satisfies 2.00≦a≦20.00. It may also be 3.00≦a≦18.00, or 5.00≦a≦15.00. If the B content is high, the magnetic permeability and withstand voltage tend to decrease. If the B content is low, the magnetic permeability, DC bias characteristics, and withstand voltage tend to decrease. If the B content is too high or too low, the withstand voltage in particular decreases.

[0029] The P content (b) satisfies 0.00≦b≦14.00. In other words, P need not be contained. It may be 2.00≦b≦12.00, or 4.00≦b≦10.00. Whether the P content is high or low, the magnetic permeability and dielectric strength tend to decrease. If the P content is too high, the dielectric strength in particular decreases.

[0030] The Si content (c) satisfies 0.00≦c≦10.00. That is, Si need not be contained. It may be 0.00≦c≦8.00, or 0.00≦c≦6.00. As the Si content increases, the magnetic permeability and withstand voltage tend to decrease.

[0031] The numerical range of b+c, which represents the sum of the P content and the Si content, is not particularly limited. For example, it may be 4.00≦b+c≦20.00. The higher the total P and Si content, the more likely the DC bias characteristics are to deteriorate.

[0032] The C content (d) satisfies 0.00≦d≦5.00. That is, C need not be contained. It may be 0.00≦d≦3.00, or 0.00≦d≦1.00. As the C content increases, the magnetic permeability, DC bias characteristics, and withstand voltage tend to decrease.

[0033] The content (e) of X2 satisfies 0.00≦e≦3.00. That is, X2 need not be contained. It may be 0.00≦e≦1.00, or 0.01≦e≦1.00. As the content of X2 increases, the DC bias characteristics and withstand voltage tend to deteriorate. When e is 1.00 or less, high magnetic permeability can be maintained. When e exceeds 1.00, the magnetic permeability tends to decrease as e increases.

[0034] The soft magnetic alloy powder according to this embodiment satisfies 70.00≦100−(a+b+c+d+e)≦96.00. That is, the total content of Fe and X1 is 70.00 at% or more and 96.00 at% or less. 72.00≦100−(a+b+c+d+e)≦88.00 or 74.00≦100−(a+b+c+d+e)≦82.00 may be satisfied. The smaller the total content of Fe and X1, the more likely Bs is to decrease. Whether the total content of Fe and X1 is large or small, the magnetic permeability, DC bias characteristics, and withstand voltage are likely to decrease.

[0035] The soft magnetic alloy powder according to this embodiment may further contain oxygen. The oxygen content relative to 100 mass% of the soft magnetic alloy powder may be 0 ppm or more and 10,000 ppm or less, or may be 300 ppm or more and 10,000 ppm or less, by mass. The higher the oxygen content, the more likely it is that the withstand voltage will improve, and the more likely it is that the magnetic permeability and DC bias characteristics will deteriorate.

[0036] The soft magnetic alloy powder of this embodiment may contain elements other than Fe, X1, B, P, Si, C, and X2 as inevitable impurities to the extent that they do not significantly affect the properties. The oxygen content is as described above. Furthermore, the inevitable impurities may contain elements other than oxygen in an amount of 0.1% by mass or less relative to 100% by mass of the soft magnetic alloy powder.

[0037] The volumetric particle size distribution F(x) of soft magnetic alloy powder is expressed as a function of multiple probability density functions f i It may be expressed by the following formulas (1) to (4) using (x) (i=1, 2, . . . , n) (n≧2).

[0038]

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[0039]

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[0040]

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[0041]

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[0042] Then, the particle diameter when the volume-based cumulative relative frequency calculated from F(x) is 10% is defined as D10, and the particle diameter when the volume-based cumulative relative frequency is 90% is defined as D90, 0<|exp(μ1)-exp(μ2)| / (D90-D10)≦1.0, 0.1 ≤ σ1 ≤ 1.1, and The relationship 0.01≦σ2≦1.5 may be satisfied.

[0043] exp(A) is e A means.

[0044] In the following description, |exp(μ1)-exp(μ2)| / (D90-D10) may be simply referred to as Z.

[0045] Equation (4) represents the probability density function of a log-normal distribution. If the particle size distribution F(x) of the soft magnetic alloy powder can be expressed as the sum of multiple probability density functions as shown in equations (1) to (3), and μ1, μ2, σ1, and σ2 in f1(x) and f2(x) satisfy all three of the above equations, a magnetic core with improved permeability, DC bias characteristics, and voltage resistance can be obtained without changing the composition of the soft magnetic alloy powder.

[0046] The left side of equation (1) is the probability density function that represents the particle size distribution of the measured soft magnetic alloy powder. The right side of equation (1) is the probability density function obtained by combining the probability density functions of multiple log-normal distributions. The sum of the squared differences between the probabilities of both in all categories is 5 × 10 -4 If: i In this case, the particle size distribution F(x) of the soft magnetic alloy powder is calculated using multiple probability density functions f i Let it be expressed using (x) (i=1, 2,...,n) (n≧2).

[0047] f i When fitting F(x) with (x), n should be as small as possible. Therefore, if F(x) can be fitted with only f1(x), that is, if F(x) can be fitted with only one log-normal distribution probability density function, n should not be set to 2 or more.

[0048] The volumetric particle size distribution of the soft magnetic alloy powder, i.e., measurement of F(x), may be evaluated using a laser diffraction particle size distribution analyzer. The particle diameter D50 at which the volumetric cumulative relative frequency calculated from F(x) is 50% may be 1.0 μm or more and 100 μm or less, 1.0 μm or more and less than 45.0 μm, or 1.5 μm or more and 44.7 μm or less. In particular, when D50 is less than 45.0 μm, the DC bias characteristics and withstand voltage are likely to be improved.

[0049] The volumetric particle size distribution of the soft magnetic alloy powder containing the soft magnetic alloy particles may be evaluated using an image obtained by observing the cross section of a magnetic core containing the soft magnetic alloy particles. Specifically, first, the cross section obtained by cutting the magnetic core is observed using a device such as SEM-EDS or EPMA.

[0050] The number of soft magnetic alloy grains to be observed should be as large as possible, at least 20,000. The observation magnification should be a magnification suitable for measuring the cross-sectional area of ​​each soft magnetic alloy grain. The observation magnification may be increased as appropriate to observe particularly small soft magnetic alloy grains.

[0051] The cross-sectional area of ​​each soft magnetic alloy particle included in the observation range is calculated. If various particles other than the soft magnetic alloy particle in question are included in the observation range, only the soft magnetic alloy particle in question is selected and the cross-sectional area is calculated. Next, the Heywood diameter of each particle is calculated from the cross-sectional area of ​​each soft magnetic alloy particle. Assuming that the shape of each particle is a sphere with a diameter equal to the above-mentioned Heywood diameter, the volume of the soft magnetic alloy particle included in the cross section of the magnetic core is calculated. The volume-based particle size distribution F(x) of the soft magnetic alloy powder is calculated from the Heywood diameter and volume of each soft magnetic alloy particle.

[0052] As described above, the value of Z may be greater than 0 and equal to or less than 1.0, and may be 0.1≦Z≦1.0. μ i There are no particular restrictions on the values ​​of (i=1, 2). For example, they may be 0.4 or greater and 4.3 or less. As mentioned above, the value of σ1 may be 0.1 or greater and 1.1 or less, and the value of σ2 may be 0.01 or greater and 1.5 or less.

[0053] The soft magnetic alloy powder according to the present embodiment may contain an amorphous phase. Furthermore, the soft magnetic alloy powder containing an amorphous phase may have a crystallization onset temperature Tx and a glass transition temperature Tg, and may have a supercooled liquid region expressed by ΔTx = Tx - Tg.

[0054] When the temperature of soft magnetic alloy powder containing amorphous material is increased, a glass transition reaction (endothermic reaction) may occur at a specific temperature. This temperature is the glass transition point Tg. At higher temperatures, a crystallization reaction (exothermic reaction) may occur at a certain temperature. This temperature is the crystallization onset point Tx. In this case, the supercooled liquid region ΔT is expressed as Tx - Tg.

[0055] The supercooled liquid region is related to the stabilization of amorphous phases, and the wider the supercooled liquid region and the larger ΔT, the higher the amorphous phase-forming ability. In contrast, if the supercooled liquid region is narrow, the amorphous phase-forming ability is low. The presence or absence of Tx, the presence or absence of Tg, and ΔT can be confirmed using a differential scanning calorimeter (DSC).

[0056] The soft magnetic alloy powder according to this embodiment may contain nanocrystals, i.e., crystals having a grain size of 50 nm or less. The soft magnetic alloy powder containing nanocrystals may be obtained by heat treating the soft magnetic alloy powder containing amorphous material.

[0057] There are no particular limitations on the method for determining whether the soft magnetic alloy powder contains amorphous matter and nanocrystals, and for example, it can be determined using XRD.

[0058] Hereinafter, a method for confirming whether the soft magnetic alloy powder of this embodiment has an amorphous structure (a structure consisting only of amorphous or a nanoheterostructure) will be described. In this embodiment, soft magnetic alloy powders having an amorphous ratio X shown in the following formula (A) of 85% or more have an amorphous structure, and soft magnetic alloy powders having an amorphous ratio X of less than 85% have a crystalline or nanocrystalline structure.

[0059] X=100-(Ic / (Ic+Ia)×100)…(A) Ic: Crystalline scattering integrated intensity Ia: Amorphous scattering integrated intensity

[0060] To calculate the amorphization rate X of the soft magnetic alloy powder, first, the soft magnetic alloy powder is subjected to crystal structure analysis by X-ray diffraction (XRD). Next, the phase is identified, and the peaks of the crystallized Fe or compound (Ic: crystalline scattering integrated intensity, Ia: amorphous scattering integrated intensity) are read. The crystallization rate is calculated from the read peak intensity, and the amorphization rate X is calculated using the above formula (A). The calculation method will be explained in more detail below.

[0061] The soft magnetic alloy powder according to this embodiment is subjected to crystal structure analysis by XRD, and profile fitting is performed using a Lorentz function to obtain a crystalline component pattern showing the crystalline scattering integrated intensity, an amorphous component pattern showing the amorphous scattering integrated intensity, and a combined pattern of these. The amorphous fraction X is calculated from the crystalline scattering integrated intensity and the amorphous scattering integrated intensity of the obtained pattern using the above formula (A). The measurement range is a diffraction angle 2θ of 30° to 60°, in which an amorphous-derived halo can be confirmed. Within this range, the error between the integrated intensity actually measured by XRD and the integrated intensity calculated using the Lorentz function is set to within 1%.

[0062] There are no particular limitations on the method for determining whether a soft magnetic alloy powder has a structure consisting of crystals with a crystal grain size of more than 50 nm or a structure consisting of nanocrystals with a crystal grain size of 50 nm or less. For example, there is a method for calculating the crystal grain size by analyzing the half-value width and evaluating the size of the crystallites, or a method for calculating the crystal grain size by observation using a TEM.

[0063] The soft magnetic alloy powder may be subjected to a coating treatment, or a coating film may be formed on the surface of the soft magnetic alloy powder. There are no particular restrictions on the material of the coating film. Coating films commonly used in this technical field, such as phosphate-based coating films and silica-based coating films, can be formed. There are no particular restrictions on the thickness of the coating film. For example, it may be greater than 0 nm and less than 50 nm, or may be 5 nm or more and less than 50 nm. The thicker the coating film, the more likely it is that the magnetic permeability will decrease, but the DC bias characteristics and voltage resistance will be improved.

[0064] The method for producing the soft magnetic alloy powder of this embodiment will be described below.

[0065] There are no particular limitations on the method for producing the soft magnetic alloy powder of this embodiment, but the following will describe the case where water atomization is used.

[0066] A method for producing soft magnetic alloy powder by water atomization will be described below.

[0067] The water atomizer used in this embodiment may be a conventional water atomizer. However, by using the special water atomizer described below, the volume-based particle size distribution F(x) can be expressed as a plurality of probability density functions f i A soft magnetic alloy powder represented by (x) (i=1, 2, . . . , n) (n≧2) is obtained.

[0068] The special water atomizer is similar to a conventional water atomizer except for the nozzle (hereinafter sometimes referred to as a spray hole) that sprays water onto the dripping molten metal being discharged.

[0069] The oxygen content of the soft magnetic alloy powder varies depending on the drying conditions when drying the soft magnetic alloy powder recovered from the water atomizer. There are no particular restrictions on the drying conditions, but the atmosphere during drying may be an atmosphere with an oxygen concentration of 5% or less, or an atmosphere with an oxygen concentration of 0.1% or less. Furthermore, in a vacuum atmosphere, i.e., an atmospheric pressure of 1×10-4 Pa~1×10 -2 It is desirable to use an atmosphere where the oxygen concentration is 0.1 Pa. In a vacuum atmosphere, the oxygen concentration will inevitably be 0.1% or less. The drying temperature may be controlled within the range of 30°C to 100°C, and the drying time may be controlled within the range of 1 hour to 48 hours. The higher the oxygen concentration during drying, the more likely the oxygen content will be. The higher the drying temperature and the longer the drying time, the more likely the oxygen content will be. The smaller the particle size of the soft magnetic alloy powder, the more likely the oxygen content will be.

[0070] In conventional water atomizers, spray holes of the same type are arranged at roughly equal intervals, and water is continuously sprayed onto the dripping molten metal from each spray hole.

[0071] In contrast, in special water atomization devices, some of the normal spray holes 11 are replaced with intermittent spray holes 13, as shown in Figure 1. As shown in Figure 1, the intermittent spray holes 13 are arranged at roughly equal intervals. There are no particular restrictions on the diameter of each spray hole. For example, it may be 0.3 mm or more and 1.5 mm or less.

[0072] Water is sprayed continuously onto the dripping molten metal from the continuous spray holes 11. In contrast, water is sprayed periodically at regular time intervals from the intermittent spray holes 13.

[0073] An example of the water pressure of water sprayed from the spray holes is shown in Figure 2. The total water pressure of water sprayed from the multiple intermittent spray holes 13 periodically alternates between 0 MPa and 5 MPa at regular time intervals. As a result, the total water pressure of water sprayed from all the spray holes also periodically alternates between 10 MPa and 15 MPa at regular time intervals.

[0074] By periodically changing the total water pressure of the water sprayed from the nozzle, the volumetric particle size distribution F(x) is calculated based on the probability density function f i A soft magnetic alloy powder represented by (x) (i=1, 2, . . . , n) (n≧2) is obtained.

[0075] At this stage, the soft magnetic alloy powder is preferably amorphous and does not contain crystals (nanocrystals).

[0076] It is preferable to heat-treat the amorphous soft magnetic alloy powder obtained by the water atomization method. For example, by performing heat treatment at 450 to 650°C for 1 to 120 minutes, the powder particles can be prevented from sintering together and becoming coarse, while diffusing the elements, allowing the powder to reach a thermodynamic equilibrium state in a short time, and eliminating strain and stress. Note that nanocrystals may precipitate at this point.

[0077] The soft magnetic alloy powder may be subjected to a coating treatment at any stage. There are no particular limitations on the coating treatment method. Any coating treatment method commonly used in this technical field may be used.

[0078] There are no particular limitations on the applications of the soft magnetic alloy powder according to this embodiment. In particular, when used in a composite material, a composite material with high magnetic permeability can be obtained.

[0079] When a composite material is produced using conventional soft magnetic alloy powder, it is necessary to increase the filling rate of the soft magnetic alloy powder in order to obtain a composite material with high magnetic permeability. However, increasing the filling rate increases the likelihood of powder particles coming into contact with each other, reducing the withstand voltage and increasing the dielectric loss. By using the soft magnetic alloy powder according to this embodiment, a composite material with high magnetic permeability can be obtained without increasing the filling rate, improving the withstand voltage.

[0080] Furthermore, when manufacturing a magnetic core containing the soft magnetic alloy powder according to this embodiment, only the soft magnetic alloy powder according to this embodiment may be used, or two or more types of powders including the soft magnetic alloy powder according to this embodiment may be mixed and used. There are no particular restrictions on the powders other than the soft magnetic alloy powder according to this embodiment. Examples include Fe powder, FeNi alloy powder, and FeCo alloy powder. In particular, if the other powders have a smaller particle size than the soft magnetic alloy powder according to this embodiment, the powder filling rate in the final magnetic component can be increased. There are no particular restrictions on the proportion of the soft magnetic alloy powder according to this embodiment in the powders after mixing. For example, it may be 20.0% or more, 50.0% or more, 75.0% or more, or 87.5% or more by mass.

[0081] The composite material containing the soft magnetic alloy powder according to this embodiment can be used, for example, as a magnetic core. In particular, it can be suitably used as a magnetic core for a power inductor. The soft magnetic alloy powder according to this embodiment can also be suitably used for magnetic components, such as thin film inductors and magnetic heads. Furthermore, magnetic cores and magnetic components using this soft magnetic alloy powder can be suitably used in electronic devices. [Example]

[0082] The present invention will be specifically described below based on examples.

[0083] (Experimental Example 1) Ingots of various materials were prepared and weighed so as to obtain master alloys with the compositions shown in Tables 1A and 1B. They were then placed in crucibles placed in a water atomization apparatus. In this example, all samples for which the oxygen content was not specifically stated had an oxygen content of approximately 1500 ppm.

[0084] Next, the master alloy was placed in a heat-resistant container placed in a water atomizer. After the cylinder was evacuated, the heat-resistant container was heated by high-frequency induction using a heating coil installed outside the heat-resistant container, and the raw metals in the heat-resistant container were melted and mixed to obtain molten metal (molten metal).

[0085] For each sample listed in Table 1A, water was continuously sprayed from a continuous spray hole at the water pressure shown in Table 1A onto the 1500°C molten metal, causing the molten metal to form numerous droplets. The diameter of the continuous spray hole was 0.8 mm. The droplets were cooled with cooling water to form fine soft magnetic alloy powder, which was then collected. The collected soft magnetic alloy powder was then dried. The drying atmosphere was a vacuum atmosphere, with a drying temperature of 50°C and a drying time of 12 hours. An oil rotary pump was used to create the vacuum atmosphere.

[0086] For each sample listed in Table 1B, water was sprayed continuously from a continuous spray hole at the water pressure shown in Table 1B, and intermittently from intermittent spray holes with the hole diameter shown in Table 1B at the water pressure, spray interval, and spray time shown in Table 1B, causing the molten metal to form multiple droplets. The diameter of the continuous spray hole was 0.8 mm. The droplets were cooled with cooling water to form fine soft magnetic alloy powder, which was then collected.

[0087] It was confirmed by ICP analysis that the composition of the master alloy and the composition of the soft magnetic alloy powder were roughly the same.

[0088] It was confirmed whether each soft magnetic alloy powder obtained contained amorphous or nanocrystals. The presence or absence of peaks due to nanocrystals was confirmed using XRD. Unless otherwise specified below, no peaks due to nanocrystals were observed.

[0089] The particle size distribution F(x) of each soft magnetic alloy powder obtained was measured using a laser diffraction particle size distribution measuring device (HELOS&RODOS (Sympatec)). D10, D50, and D90 were determined from the obtained particle size distribution F(x).

[0090] Furthermore, the particle size distribution F(x) of each soft magnetic alloy powder is expressed by the formulas (1) to (4). Specifically, one or more probability density functions f i (x) can be used to fit F(x) i(x) is specified. At that time, n and μ i , σ i When n ≥ 2, Z = |exp(μ1)-exp(μ2)| / (D90-D10) was calculated. The results are shown in each table.

[0091] DSC measurement was performed on each of the obtained soft magnetic alloy powders using STA449F3 (NETZSCH). In Experimental Example 1, it was confirmed that the soft magnetic alloy powders of all the examples had a crystallization onset temperature Tx, a glass transition temperature Tg, and a supercooled liquid region ΔTx.

[0092] A toroidal core was produced from each soft magnetic alloy powder. Specifically, a phenolic resin was mixed with each soft magnetic alloy powder to obtain a mixture of soft magnetic alloy powder and phenolic resin. The amount of phenolic resin was set to 3 mass% of the total mixture. Next, the mixture was stirred and granulated to obtain granulated powder. Specifically, a general planetary mixer was used as the mixer to granulate the powder to a size of about 500 μm. Next, the obtained granulated powder was subjected to a surface pressure of 4 ton / cm. 2 (392 MPa) to produce a toroidal-shaped compact with an outer diameter of 13 mm, an inner diameter of 8 mm, and a height of 6 mm. The resulting compact was cured at 150°C to produce a toroidal core. Additionally, a cylindrical compact with a diameter of 8 mm and a height of 5 mm was produced for pressure resistance measurements. The resulting compact was cured at 150°C to produce a cylindrical core.

[0093] Then, UEW wire was wound around the toroidal core, and the relative permeability was measured at 100 kHz using a 4284A PRECISION LCR METER (Hewlett-Packard). The results are shown in Table 1. A relative permeability of 10.0 or more was rated as good, and a relative permeability of 15.0 or more was rated as even better.

[0094] For DC bias characteristics, inductance was measured while applying a DC current starting from 0 to the above toroidal core. The value of the applied DC current (Isat) was measured when the inductance dropped to 10% (one digit drop) of the inductance when the DC current was 0. Inductance measurements were performed using a 4284A PRECISION LCR METER (Hewlett-Packard) at a frequency of 100 kHz and a measurement current of 0.3 mA. The results are shown in the tables. DC bias characteristics were considered to be good when Isat was 5.5 A or higher.

[0095] To measure the breakdown voltage, first, an In-Ga electrode was formed on each end face of the cylindrical core. Next, a voltage was applied to the cylindrical core using a voltage resistance tester (THK-2011ADMPT manufactured by Tama Densoku Co., Ltd.), and the voltage value when a current of 1 mA flowed was measured. The measured voltage value was then divided by the height of the cylindrical core (the distance between the end faces of the cylindrical core) to calculate the breakdown voltage of the cylindrical core.

[0096] [Table 1A]

[0097] [Table 1B]

[0098] Table 1A shows samples in which the water pressure during water atomization was always constant, while Table 1B shows samples with the same composition as the samples shown in Table 1A, but in which the water pressure during water atomization changed periodically.

[0099] When the composition was within the predetermined range, Bs, relative permeability, DC bias characteristics, and breakdown voltage were all good. In contrast, Comparative Examples 1 and 17, which contained too much B, showed poor Bs, DC bias characteristics, and breakdown voltage. Comparative Examples 16 and 32, which contained too much Fe and Co, showed poor DC bias characteristics and breakdown voltage.

[0100] When comparing cases where the conditions were the same except for the water spray state, the soft magnetic alloy powders of the examples listed in Table 1B all had superior DC bias characteristics and pressure resistance, and had approximately the same relative permeability, compared to the soft magnetic alloy powders of the examples listed in Table 1A.

[0101] All of the soft magnetic alloy powders listed in Table 1A had n = 1. That is, they were soft magnetic alloy powders whose particle size distribution could be expressed by only one probability density function. In contrast, all of the soft magnetic alloy powders listed in Table 1B had n = 3. That is, they were soft magnetic alloy powders whose particle size distribution could be expressed by combining multiple probability density functions. All of the soft magnetic alloy powders of the examples listed in Table 1B had Z, σ1, and σ2 within the specified ranges. It is believed that this is due to the fact that the soft magnetic alloy powders of the examples listed in Table 1B have improved DC bias characteristics and voltage resistance compared to the soft magnetic alloy powders of the examples listed in Table 1A.

[0102] Figure 3 shows a graph of f1(x) in Example 5. Figure 4 shows graphs of f1(x) and f2(x) in Example 21. f3(x) is omitted in Figure 4. In both graphs, the horizontal axis represents particle diameter (unit: μm) and the vertical axis represents probability density.

[0103] (Experimental Example 2) Experimental Example 2 was carried out under the same conditions as Example 21 of Experimental Example 1, except that the composition of the soft magnetic alloy powder was changed. The results are shown in Tables 2A and 2B.

[0104] [Table 2A]

[0105] [Table 2B]

[0106] Each example having a composition within the predetermined range exhibited good characteristics. In contrast, Comparative Example 33, which contained too much B, Comparative Example 42, which contained too little B, Comparative Example 52, which contained too much P, Comparative Example 58, which contained too much Si, and Comparative Example 67, which contained too much C, all exhibited significantly reduced breakdown voltage.

[0107] (Experimental Example 3) In Experimental Example 3, except that the composition of the soft magnetic alloy powder was changed, the experiments were carried out under the same conditions as in Examples 19 to 24 of Experimental Example 1. The results are shown in Tables 3A and 3B.

[0108] [Table 3A]

[0109] [Table 3B]

[0110] Each of the examples in which the composition was within the predetermined range exhibited good characteristics, whereas Comparative Examples 74, 81, 88, 95, 102, and 109 in which the Co content was too high all exhibited a significant decrease in breakdown voltage.

[0111] (Experimental Example 4) In Experimental Example 4, X1 was changed to Ni, and the experiment was carried out in the same manner as in Experimental Example 3. The results are shown in Tables 4A and 4B.

[0112] [Table 4A]

[0113] [Table 4B]

[0114] Each example having a composition within the predetermined range exhibited good characteristics. In contrast, Comparative Examples 116, 123, 130, 137, 144, and 151, which contained too much Ni, exhibited a significant decrease in breakdown voltage. Comparative Example 116 also exhibited a decrease in Bs.

[0115] (Experimental Example 5) In Experimental Example 5, X1 was changed to Co and Ni, and the same procedure as in Experimental Example 3 was carried out. The results are shown in Table 5.

[0116] [Table 5]

[0117] Each of the Examples, in which the composition was within the prescribed range, exhibited good characteristics. In contrast, Comparative Examples 157, 163, 168, 172, 175, and 176, in which the total content of Co and Ni was too high, all exhibited a significant decrease in breakdown voltage.

[0118] (Experimental Example 6) Example 21, which did not contain C, and Example 63, which did contain C, were run under the same conditions except that part of the Fe and part of the Co were replaced with X2. The results are shown in the tables. Tables 6A and 7A to 7D show the results of Example 21 run under the same conditions except that part of the Fe and part of the Co were replaced with X2. Tables 6B and 8A to 8B show the results of Example 63 run under the same conditions except that part of the Fe and part of the Co were replaced with X2.

[0119] [Table 6A]

[0120] [Table 6B]

[0121] [Table 7A]

[0122] [Table 7B]

[0123] [Table 7C]

[0124] [Table 7D]

[0125] [Table 8A]

[0126] [Table 8B]

[0127] Each example having a composition within the specified range exhibited excellent characteristics. In contrast, Comparative Examples 183, 190, 197, 204, 211, and 218, which contained too much X2, all exhibited reduced breakdown voltage. Furthermore, some of the comparative examples also exhibited reduced Bs, relative permeability, and / or DC bias characteristics.

[0128] (Experimental Example 7) The same conditions were used as in Example 21, except that the spray conditions for the water intermittently sprayed from the intermittent spray holes were changed as appropriate. The results are shown in Table 9. In Table 9, the results of Example 5 are shown for reference.

[0129] [Table 9]

[0130] In each example whose composition was within the specified range, good properties were obtained even when the water spray conditions were changed. Furthermore, the value of n tended to increase as the water pressure and spray time were increased. In other words, the higher the water pressure and the longer the spray time, the more easily the powder could be expressed as a particle size distribution by synthesizing multiple probability density functions.

[0131] (Experimental Example 7) Examples 5 and 21 were carried out under the same conditions except that the water spraying conditions were changed as appropriate. The results are shown in Table 10. Furthermore, the oxygen content of each soft magnetic alloy powder shown in Table 10 varied greatly depending on the D50 value, with the examples having smaller D50 values ​​tending to have larger oxygen contents. However, the oxygen content in all examples was 300 ppm or more and 10,000 ppm or less.

[0132] [Table 10]

[0133] When the particle size of the soft magnetic alloy particles was changed by changing the atomization conditions, the larger the particle size, the higher the relative permeability and the lower the DC bias characteristics. Furthermore, when other conditions were substantially the same, the soft magnetic alloy powder with n=3 had superior relative permeability, DC bias characteristics, and pressure resistance compared to the soft magnetic alloy powder with n=1.

[0134] (Experimental Example 8) The same conditions were used for Comparative Example 17 and Examples 18 to 25, except that the soft magnetic alloy powder obtained after water atomization was subjected to heat treatment. The heat treatment temperature was (Tx-100)°C, and the heat treatment time was 60 min. The results are shown in Table 11.

[0135] [Table 11]

[0136] From Table 11, when the content of FeCo was 78.00 at% or less, the soft magnetic alloy powder after the heat treatment also had a glass transition temperature Tg. On the other hand, when the content of FeCo was 80.00 at% or more, the soft magnetic alloy powder after the heat treatment did not have a glass transition temperature Tg.

[0137] (Experimental Example 9) Example 188 was carried out under the same conditions, except that the soft magnetic alloy powder obtained after water atomization was subjected to heat treatment. The heating rate during heat treatment is shown in Table 12. Specifically, in Example 350, the heating rate was 10°C / min. In Example 351, the heating rate was 40°C / min. In Example 352, the heating rate was 100°C / min. The heat treatment conditions for each Example were selected so that the relative permeability was maximized in each Example. Specifically, in each Example, the heat treatment temperature was selected from 400 to 500°C, and the heat treatment time was selected from 1 to 30 minutes.

[0138] [Table 12]

[0139] It was confirmed whether each soft magnetic alloy powder obtained for Examples 350 to 352 contained amorphous or nanocrystals. The presence or absence of peaks due to nanocrystals was confirmed using XRD. Peaks due to nanocrystals were observed in Examples 350 to 352. In other words, it was confirmed that nanocrystals were contained. The average particle size of the nanocrystallites in Examples 350 to 352 is also shown in Table 12. There was a tendency that the particle size of the nanocrystallites became smaller and the relative permeability became higher as the heating rate increased.

[0140] (Experimental Example 10) Experimental Example 10 was carried out under the same conditions as Example 21, except that the soft magnetic alloy powder of Example 21 was coated with a phosphate-based coating or a silica-based coating. The phosphate-based coating was performed by spraying a solution containing phosphate onto the soft magnetic alloy powder. The silica-based coating was performed by spraying a solution containing SiO2 onto the soft magnetic alloy powder. The average thickness of the phosphate-based coating and the average thickness of the silica-based coating were controlled to the values ​​listed in Table 13. The results are shown in Table 13. Parameters not listed in Table 13 were equivalent to those of Example 21 in all examples listed in Table 13.

[0141] [Table 13]

[0142] Examples 353 to 360 had various excellent properties comparable to those of Example 21. In addition, the relative permeability tended to increase as the coating became thinner. The DC bias characteristics and withstand voltage tended to increase as the coating became thicker.

[0143] (Experimental Example 10) The soft magnetic alloy powder of Example 21 was designated Powder A (powder with a D50 of 24.7 μm). The powders shown in Table 14 (soft magnetic alloy powder of Example 334, Fe powder, FeNi alloy powder, and FeCo alloy powder) were designated Powder B (powder with a D50 of 3.2 μm). The powders shown in Table 14 (soft magnetic alloy powder of Example 333, Fe powder, FeNi alloy powder, and FeCo alloy powder) were designated Powder C (powder with a D50 of 1.5 μm). The FeNi alloy powder is a powder with an atomic ratio of Fe:Ni=30:70. The FeCo alloy powder is a powder with an atomic ratio of Fe:Co=50:50. Furthermore, Examples 21, 333, and 334 have the same composition.

[0144] The same conditions as in Example 21 were used for powders obtained by mixing two or more powders selected from Powder A, Powder B, and Powder C in the mass ratios shown in Tables 14A to 14C. The results are shown in Tables 14A to 14C. It was confirmed that the mixed powders of each example shown in Tables 14A to 14C had compositions within the above ranges and satisfied the following conditions: 0<|exp(μ1)-exp(μ2)| / (D90-D10)≦1.0, 0.1≦σ1≦1.1, and 0.01≦σ2≦1.5.

[0145] [Table 14A]

[0146] [Table 14B]

[0147] [Table 14C]

[0148] The soft magnetic alloy powders shown in Examples 361 to 372 in Table 14A and Examples 1001 to 1012 in Table 14B had various excellent properties comparable to those of each Example such as Example 21. Moreover, the soft magnetic alloy powders shown in Examples 1013 to 1024 in Table 14C had lower relative permeability and higher DC bias characteristics than the soft magnetic alloy powders of the other Examples of Experimental Example 10. This is because the D50 of the soft magnetic alloy powders was smaller.

[0149] (Experimental Example 11) The same procedures as in Example 21 or Example 334 were carried out except that the oxygen content was changed. The results are shown in Table 15. The oxygen content was changed by controlling the drying conditions. Specifically, the atmosphere during drying was set at an atmospheric pressure of 1×10 -4 Pa~1×10 -2 The drying temperature was set to 50°C and the drying time was set to 12 hours.

[0150] [Table 15]

[0151] Each example shown in Table 15, in which the oxygen content was 10,000 ppm or less, exhibited good characteristics. The smaller the particle size of the soft magnetic alloy powder, the higher the oxygen content. However, for samples in which the oxygen content was reduced below that of Example 21 by lowering the atmospheric pressure and / or oxygen concentration, the characteristics were almost the same as those of Example 21. The same tendency as above was observed even when Example 21 was replaced with Example 334. Furthermore, the higher the oxygen content, the better the withstand voltage, but the lower the DC bias characteristics and magnetic permeability. This is thought to be because the soft magnetic alloy powder contains more oxides as the oxygen content increases.

[0152] (Experimental Example 12) The same conditions were used for Example 21, except that various test conditions were appropriately changed so that n = 5. Furthermore, σ2 was mainly changed by controlling the spray time, and σ1 was mainly changed by changing the water pressure from the continuous spray hole and the intermittent spray hole. The results are shown in Table 16.

[0153] [Table 16]

[0154] The soft magnetic alloy powders of the examples shown in Table 16 had various excellent properties similar to those of the other examples. [Explanation of symbols]

[0155] 11...Continuous spray hole 13...Intermittent spray hole

Claims

1. Composition formula (Fe 1-p X1 p ) 100-(a+b+c+d+e) B a P b Si c C d X2 e (atomic ratio), X1 is at least one selected from Co and Ni, and X2 is at least one selected from Ti, Zr, Hf, Nb, Ta, Mo, Cr, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Mn, Sn, As, Sb, Bi, N, Au, Cu, rare earth elements, and platinum group elements; 0≦p≦0.5, 2.00≦a≦20.00, 0.00≦b≦14.00, 0.00≦c≦10.00, 0.00≦d≦5.00, 0.00≦e≦3.00, and 70.00≦100-(a+b+c+d+e)≦96.00 Soft magnetic alloy powder.

2. The volume-based particle size distribution F(x) of the soft magnetic alloy powder is expressed by a plurality of probability density functions f i (x) (i=1, 2, ..., n) (n≧2) and are expressed by the following formulas (1) to (4): The particle diameter when the volume-based cumulative relative frequency calculated from F(x) is 10% is defined as D10, and the particle diameter when the volume-based cumulative relative frequency is 90% is defined as D90. 0<|exp(μ 1 )-exp(μ 2 )| / (D90-D10)≦1.0、 0.1≦σ 1 ≦1.1, and 0.01≦σ 2 2. The soft magnetic alloy powder according to claim 1, wherein the ρ is ≦1.

5. [Equation 1] [Equation 2] [Equation 3] [Equation 4]

3. 3. The soft magnetic alloy powder according to claim 1, wherein D50 is the particle diameter at which the volume-based cumulative relative frequency is 50%, and D50 is 1.0 μm or more and less than 45.0 μm.

4. 3. The soft magnetic alloy powder according to claim 1, wherein the oxygen content is 300 ppm or more and 10,000 ppm or less.

5. The soft magnetic alloy powder according to claim 1 or 2, which contains an amorphous phase.

6. 6. The soft magnetic alloy powder according to claim 5, wherein the soft magnetic alloy powder has a crystallization onset temperature Tx and a glass transition temperature Tg, and has a supercooled liquid region expressed by ΔTx=Tx−Tg.

7. 3. The soft magnetic alloy powder according to claim 1, which contains nanocrystals.

8. A magnetic core comprising the soft magnetic alloy powder according to claim 1 or 2.

9. 9. The magnetic core of claim 8, comprising two or more types of powder.

10. A magnetic part comprising the soft magnetic alloy powder according to claim 1 or 2.

11. An electronic device comprising the soft magnetic alloy powder according to claim 1 or 2.

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