Soft magnetic alloys and magnetic components

Abstract

This invention provides a soft magnetic alloy that simultaneously possesses high saturation magnetic flux density Bs and high corrosion resistance. This soft magnetic alloy contains a composition of the formula ((Fe...)... (1－(α+β)) Co α Ni β ) 1－γ X1 γ ) (1－(a+b+c+d+e)) B a P b Si c C d Cr e The composition (atomic ratio) includes Mn. X1 is selected from one or more of Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements. a~e and α~γ are within the specified range. When the Mn content is set as f (at%), 0.002 ≤ f < 3.0. The corrosion potential is between -630mV and -50mV, and the corrosion current density is 0.3μA / cm. 2 Above 45μA / cm 2 the following.

Description

Technical Field

[0001] This invention relates to soft magnetic alloys and magnetic components. Background Technology

[0002] Patent Document 1 discloses an invention of a highly corrosion-resistant amorphous alloy. Patent Document 2 discloses an invention of an amorphous soft magnetic alloy. Patent Document 3 discloses an invention of amorphous alloy powder.

[0003] Existing technical documents

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-293099

[0006] Patent Document 2: Japanese Patent Application Publication No. 2007-231415

[0007] Patent Document 3: Japanese Patent Application Publication No. 2014-167139 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] To obtain a high saturation magnetic flux density Bs, it is generally known to increase the Fe content. However, increasing the Fe content tends to reduce corrosion resistance.

[0010] The purpose of this invention is to provide soft magnetic alloys that simultaneously possess high saturation magnetic flux density Bs and high corrosion resistance.

[0011] Technical solutions for solving technical problems

[0012] To achieve the above objectives, the soft magnetic alloy of the present invention contains a composition of ((Fe) (1－(α+β)) Co α Ni β ) 1－γ X1 γ ) (1－(a+b+c+d+e)) B a P b Si c C d Cr e The composition of (atomic ratio) and Mn, where,

[0013] X1 is selected from one or more of the following elements: Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements.

[0014] 0.020≤a≤0.200,

[0015] 0≤b≤0.070,

[0016] 0≤c≤0.100,

[0017] 0≤d≤0.050,

[0018] 0≤e≤0.040,

[0019] 0.005≤α≤0.700,

[0020] 0≤β≤0.200,

[0021] 0 ≤ γ < 0.030,

[0022] 0.720≤1-(a+b+c+d+e)≤0.900,

[0023] When the Mn content is set as f (at%), 0.002 ≤ f < 3.0.

[0024] In a 0.5 mol / L NaCl aqueous solution, the spontaneous potential was set as the reference potential, the measurement potential range was set to -0.3 V to 0.3 V, and the potential scan rate was set to 0.833 mV / s. Based on the potential and current values ​​measured by the LSV method, the corrosion potential calculated by Tafel extrapolation was between -630 mV and -50 mV, and the corrosion current density was 0.3 μA / cm². 2 Above 45μA / cm 2 the following.

[0025] It can be 0.003≤f / α(1-γ){1-(a+b+c+d+e)}≤710.

[0026] It can be 0.050≤α≤0.600.

[0027] It can be 0.100≤α≤0.500 and 0.050≤f / α(1-γ){1-(a+b+c+d+e)}≤8.0.

[0028] It can be 0.001≤e≤0.020 and 1.00≤α(1-γ){1-(a+b+c+d+e)}×e×10000≤50.0.

[0029] It can be 0 ≤ b ≤ 0.050.

[0030] It can be 0.780≤1-(a+b+c+d+e)≤0.890.

[0031] It can be 0.001≤β≤0.050.

[0032] It can be 0 < γ < 0.030.

[0033] The amorphization rate X shown in (1) below can be 85% or higher.

[0034] X=100-(Ic / (Ic+Ia)×100)…(1)

[0035] Ic: Integral intensity of crystalline scattering

[0036] Ia: Integral intensity of amorphous scattering.

[0037] It can be in powder form.

[0038] The average Wadell roundness of particles contained in powder-form soft magnetic alloys can be above 0.80.

[0039] The magnetic component of the present invention includes the soft magnetic alloy described above. Attached Figure Description

[0040] Figure 1 This is an example of a chart obtained through X-ray crystal structure analysis.

[0041] Figure 2 Through the Figure 1 An example of a pattern obtained by contour fitting of a chart.

[0042] Figure 3 This is an example of a photograph taken after a 60-minute immersion test on a Co-free soft magnetic alloy strip.

[0043] Figure 4 This is an example of a photograph taken after a 60-minute immersion test on a soft magnetic alloy strip containing Co.

[0044] Figure 5 This is a chart showing the differences in roundness caused by the presence or absence of Mn and the varying content of Co. Detailed Implementation

[0045] The embodiments of the present invention will be described below.

[0046] The soft magnetic alloy of this embodiment contains a composition of ((Fe) (1－(α+β)) Co α Ni β ) 1－γ X1 γ ) (1－(a+b+c+d+e)) B a P b Si c C d Cr e The composition of (atomic ratio) and Mn, where,

[0047] X1 is selected from one or more of the following elements: Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements.

[0048] 0.020≤a≤0.200,

[0049] 0≤b≤0.070,

[0050] 0≤c≤0.100,

[0051] 0≤d≤0.050,

[0052] 0≤e≤0.040,

[0053] 0.005≤α≤0.700,

[0054] 0≤β≤0.200,

[0055] 0 ≤ γ < 0.030,

[0056] 0.720≤1-(a+b+c+d+e)≤0.900,

[0057] When the content of Mn is set as f(at%), 0.002≤f<3.0.

[0058] The above composition is characterized by the presence of Co and Mn, particularly within a specified range. Soft magnetic alloys with the above composition exhibit high saturation magnetic flux density (Bs) and corrosion resistance.

[0059] The saturation magnetic flux density Bs can be above 1.5T.

[0060] Regarding corrosion resistance, specifically, in a 0.5 mol / L NaCl aqueous solution, with the spontaneous potential set as the reference potential, the measured potential range set to -0.3V to 0.3V, and the potential scan rate set to 0.833 mV / s, the corrosion potential calculated using the Tafel extrapolation method based on the potential and current values ​​measured by the LSV method is above -630 mV and below -50 mV, with a corrosion current density of 0.3 μA / cm². 2 Above 45μA / cm 2 the following.

[0061] The methods for determining corrosion potential and corrosion current density are described below.

[0062] First, a soft magnetic alloy strip with a width of 4–6 mm and a thickness of 15–25 μm, prepared by the method described later, was used as the soft magnetic alloy for measurement. Next, the surface of the soft magnetic alloy was ultrasonically cleaned for 1 minute with 99% modified ethanol, followed by ultrasonic cleaning with acetone for 1 minute. Then, the surface of the soft magnetic alloy immersed in the NaCl aqueous solution described later was prepared to have a width of 4–6 mm and a length of 9–11 mm.

[0063] Next, the corrosion potential and corrosion current of the obtained soft magnetic alloy were measured. The corrosion potential and corrosion current were measured using an electrochemical measuring instrument that can be measured by the LSV method. For example, the measurements were performed using a Bio-Logic SP-150 potentiostat / galvanostat and Bio-Logic's "EC-Lab" software via Tafel extrapolation.

[0064] Specifically, a soft magnetic alloy is used as the working electrode, immersed in a 0.5 mol / L NaCl aqueous solution (25°C). The NaCl aqueous solution is measured and added in 10 mL of a glass electrochemical test cell. The electrochemical test cell uses a cell with an outer diameter of 28 mm, a height of 45 mm, and an electrode spacing of 13 mm. For example, a Pyrex (registered trademark) glass electrochemical test cell VB2 (manufactured by EC FRONTIER CO.,LTD) is used. As the counter electrode, Pt with a sufficient surface area to avoid rate limiting of the reaction at the working electrode is used. There is no upper limit to the surface area of ​​the counter electrode; that is, even if the surface area is increased, the corrosion potential and corrosion current will not change. As the reference electrode, an Ag / AgCl electrode immersed in a supersaturated KCl aqueous solution is used.

[0065] The soft magnetic alloy was immersed in a NaCl aqueous solution and allowed to stand for 20 minutes. This was to eliminate convection in the NaCl aqueous solution. The spontaneous potential after standing was set as the reference potential, and the measurement potential range was set to -0.3V to 0.3V. The potential scan rate was set to 0.833mV / s from low potential to high potential, and the potential and current values ​​were measured by the LSV method. The corrosion potential and corrosion current were calculated using the Tafel extrapolation method based on the obtained potential and current values. The corrosion potential is the potential at which the absolute value of the current detected near the spontaneous potential reaches its minimum. The corrosion current is determined by the intersection of a straight line extending perpendicularly from the corrosion potential and the Tafel line (described later). The corrosion current density is calculated by calculating the corrosion current per unit area based on the corrosion current and the surface area of ​​the sample being measured. Furthermore, the surface area of ​​the sample is the sum of the surface areas of the entire portion immersed in the NaCl aqueous solution.

[0066] Furthermore, the Tafel line extrapolated using the Tafel extrapolation method is obtained using the cathodic reaction side. This is because when using the anodic reaction side, it is difficult to obtain a Tafel line due to the influence of corrosion-related products and other factors.

[0067] The following explains the relationship between the above-mentioned composition (especially the content of Co, Mn and Cr) and the corrosion resistance (corrosion potential and corrosion current density) of soft magnetic alloys.

[0068] First, when a soft magnetic alloy containing no Co, Mn, or Cr is immersed in water, rust forms almost simultaneously on all surfaces of the soft magnetic alloy within a short period of time. For example, in the example described later, sample number 1, the corrosion potential shows an excessively low value, while the corrosion current density shows an excessively high value.

[0069] When a soft magnetic alloy with added Cr (replacing a portion of Fe with Cr) is immersed in water, multiple rust spots appear on the soft magnetic alloy. That is, the corrosion becomes uneven. Furthermore, it is known that the higher the Cr content, the lower the Bs content. Specifically, it is known that the Bs content decreases by approximately 0.05 to 0.1T per 1 at% of Cr. Additionally, it is known that approximately 5 at% or more of Cr needs to be added to achieve the desired corrosion resistance. For example, Figure 3 The results are from a 60-minute immersion test on a soft magnetic alloy strip containing approximately 1 at% Cr but no Co. Figure 3 The soft magnetic alloy is the comparative example, sample number 167, described later. Significant reddish-brown rust formed on the entire surface of the soft magnetic alloy strip. Furthermore, the soft magnetic alloy immersion test was conducted by immersing the alloy, which had been ultrasonically cleaned for 1 minute with 99% modified ethanol and then ultrasonically cleaned for 1 minute with acetone, into distilled water.

[0070] Here, when a soft magnetic alloy with a composition that replaces Cr with Co (a composition where a portion of Fe is replaced with Co) is immersed in water, the time until rust spots appear is longer compared to the case where Cr is added but Co is not added. This can be attributed to the fact that by replacing a portion of Fe with Co, the corrosion potential of the soft magnetic alloy increases, and the corrosion current density decreases. A higher corrosion potential makes corrosion less likely to occur; a lower corrosion current density makes it easier to reduce the corrosion rate. For example, in samples 13 and 25 described later, when a portion of Fe in sample 1 is replaced with Co, the corrosion potential increases and the corrosion current density decreases compared to sample 1.

[0071] When a portion of the Fe is replaced with Co, and then a portion of the Fe is replaced with Cr, the rust spots are further reduced. This can be attributed to the fact that, for soft magnetic alloys containing Co, replacing a portion of the Fe with Cr slightly increases the corrosion potential and significantly reduces the corrosion current density. For example, Figure 4 The results are from a 60-minute immersion test on a soft magnetic alloy strip containing approximately 1 at% Cr after replacing a portion of the Fe with Co. Figure 4 The soft magnetic alloy described later, sample number 173. Figure 4 In the middle, only multiple rust spots were produced on the soft magnetic alloy thin strip. No rust spots were produced as... Figure 3 The image shows a large, reddish-brown rust covering the entire surface of the soft magnetic alloy strip, as seen when Co is not present.

[0072] Here, when 0.002 at% to less than 3.0 at% Mn is added to a soft magnetic alloy, the corrosion potential increases.

[0073] Without replacing a portion of the Fe with Co, the increase in corrosion potential and the decrease in corrosion current density resulting from the addition of Mn are small. Therefore, even with the addition of Mn, the corrosion resistance of soft magnetic alloys is almost unaffected.

[0074] However, by replacing a portion of Fe with Co within the aforementioned range, the increase in corrosion potential and the decrease in corrosion current density resulting from the addition of Mn become greater. Furthermore, the corrosion resistance of the soft magnetic alloy increases. Additionally, replacing a portion of Fe with Co also increases Bs, but with excessive replacement, Bs actually decreases.

[0075] The components of the soft magnetic alloy of this embodiment will be described in detail below.

[0076] The content (a) of B is 0.020 ≤ a ≤ 0.200. From the viewpoint of increasing Bs, it is preferable to be 0.020 ≤ a ≤ 0.150. From the viewpoint of improving corrosion resistance, it is preferable to be 0.050 ≤ a ≤ 0.200. That is, it is particularly preferable to be 0.050 ≤ a ≤ 0.150. When a is too large, Bs tends to decrease.

[0077] The phosphorus (P) content (b) is 0 ≤ b ≤ 0.070. That is, it can be P-free. Preferably, it is 0 ≤ b ≤ 0.050. In addition, from the viewpoint of improving corrosion resistance, b is preferably 0.001 or more; from the viewpoint of improving Bs, b is preferably 0.050 or less. There is a trend that the higher the B content, the better the corrosion resistance, but if b is too high, Bs tends to decrease.

[0078] The Si content (c) is 0 ≤ c ≤ 0.100. That is, Si can be absent. Preferably, 0 ≤ c ≤ 0.070. When c is too high, Bs tends to decrease. Therefore, within the above range, there is a trend that the larger c is, the better the corrosion resistance. However, when c is too high, the rate of increase in corrosion potential brought about by the presence of Co becomes smaller, making it difficult to achieve the reduction in corrosion current density brought about by the presence of Co. As a result, the effect of improving corrosion resistance by the presence of Co is smaller.

[0079] The C content (d) is 0 ≤ d ≤ 0.050. That is, C can be absent. Preferably, 0 ≤ d ≤ 0.030, and more preferably 0 ≤ d ≤ 0.020. When d is too large, Bs tends to decrease.

[0080] The Cr content (e) is 0 ≤ e ≤ 0.040. That is, it can be Cr-free. It can also be 0 ≤ e ≤ 0.020 or 0.001 ≤ e ≤ 0.020. There is a trend that the larger the e, the better the corrosion resistance, but if e is too large, Bs tends to decrease.

[0081] The Co content (α) relative to Fe is 0.005 ≤ α ≤ 0.700. It can be 0.010 ≤ α ≤ 0.600, 0.030 ≤ α ≤ 0.600, or 0.050 ≤ α ≤ 0.600. By keeping α within the above range, both Bs and corrosion resistance are improved. From the viewpoint of increasing Bs, 0.050 ≤ α ≤ 0.500 is preferred. There is a tendency for higher α to lead to better corrosion resistance, but if α is too high, Bs tends to decrease.

[0082] Furthermore, when α is below 0.500 or a is below 0.150, it is easy for Bs to reach above 1.50T.

[0083] The Ni content (β) relative to Fe is 0 ≤ β ≤ 0.200. That is, it can be Ni-free, or it can be 0.005 ≤ β ≤ 0.200. From the perspective of increasing Bs, it can be 0 ≤ β ≤ 0.050, 0.001 ≤ β ≤ 0.050, or 0.005 ≤ β ≤ 0.010. There is a trend that the larger the β, the better the corrosion resistance, but when β is too large, Bs decreases.

[0084] X1 is selected from one or more of Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements. X1 may also be selected from one or more of Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, rare earth elements, and platinum group elements. Additionally, rare earth elements include Sc, Y, and lanthanides. Platinum group elements include Ru, Rh, Pd, Os, Ir, and Pt. X1 may be present as an impurity or intentionally added. The content (γ) of X1 is 0 ≤ γ < 0.030. That is, X1 may also replace amounts less than 3.0% relative to the combined content of Fe, Co, and Ni.

[0085] It can also be 0 < γ < 0.030.

[0086] Especially when the soft magnetic alloy is in the form of a thin strip, it can also be 0 ≤ γ ≤ 0.028. Furthermore, especially when the soft magnetic alloy is in the form of a powder, it can also be 0.000 ≤ γ ≤ 0.028.

[0087] The total content of Fe, Co, Ni, and X1 (1-(a+b+c+d+e)) is 0.720≤1-(a+b+c+d+e)≤0.900. Alternatively, it can be 0.780≤1-(a+b+c+d+e)≤0.890. Under these conditions, Bs is easily increased.

[0088] Alternatively, the product of the Co content and the Cr content can be 0.001≤e≤0.020 and 1.00≤α(1-γ){1-(a+b+c+d+e)}×e×10000≤50.0. That is, the product of the Co content and the Cr content can also be within a specific range. Under the condition of satisfying the above formula, it is easy to obtain both high corrosion resistance and high Bs.

[0089] The soft magnetic alloy of this embodiment contains, in addition to being composed of ((Fe) (1－(α+β)) Co α Ni β ) 1－γ X1 γ ) (1－(a+b+c+d+e)) B a P b Si c C d Cr eIn addition to the components constituted by the atomic ratio, it also contains Mn. Furthermore, when the Mn content is set as f (at%), 0.002 ≤ f < 3.0. The base value for Mn content is the total content of Fe, Co, Ni, X1, B, P, Si, C, and Cr. By keeping the Mn content within the above range, Bs and corrosion resistance are improved. If the Mn content is too low, corrosion resistance decreases. If the Mn content is too high, the soft magnetic alloy is prone to containing coarse crystals, resulting in decreased corrosion resistance.

[0090] Furthermore, when the Mn content is set as f(at%), it can also satisfy 0.003≤f / α(1-γ){1-(a+b+c+d+e)}≤710. That is, when the Co content relative to the components composed of the above formula is set as the base, the Mn content ratio can also be within the above range.

[0091] Furthermore, when the soft magnetic alloy is in powder form, the sphericity of the particles (described later) tends to increase compared to the case containing Co but not Mn.

[0092] Generally, when producing soft magnetic alloy powders, the oxygen content in the molten metal is more susceptible to influence than when producing soft magnetic alloy strips. Furthermore, the presence of oxygen in the molten metal tends to decrease the sphericity of the particles. Specifically, when the soft magnetic alloy powder contains manganese (Mn), the oxygen content in the molten metal tends to decrease during powder production processes such as gas atomization due to Mn's deoxidizing effect. Moreover, the lower the oxygen content, the more likely the sphericity of the particles will improve.

[0093] Figure 5 The graphs shown in Tables 1A to 1M (described later) compare the results for the soft magnetic alloy powders with f = 0 (dashed line) and f = 0.040 (solid line). The graphs show that, in the absence of Mn, the sphericity of the particles is significantly reduced by the presence of Co. That is, it is difficult to improve the sphericity of the particles when only Co is present and no Mn is present. In contrast, even with the presence of Co, the sphericity is adequately maintained when Mn is present.

[0094] The soft magnetic alloy of this embodiment may also contain elements other than those described above as unavoidable impurities. For example, it may contain 0.1% or less of these elements relative to 100% by mass of the soft magnetic alloy.

[0095] Furthermore, the amorphization rate X of the soft magnetic alloy described in (1) of this embodiment is preferably 85% or higher. In the case of a structure with a high amorphization rate X, compared to a structure with a low amorphization rate X, the corrosion potential tends to be higher, and the corrosion current density tends to be lower. Moreover, the corrosion resistance of the soft magnetic alloy is easily improved.

[0096] X=100-(Ic / (Ic+Ia)×100)…(1)

[0097] Ic: Integral intensity of crystalline scattering

[0098] Ia: Integral intensity of amorphous scattering

[0099] Structures with a high amorphization rate (X) are those composed primarily of amorphous materials or of heteroamorphous materials. Structures composed of heteroamorphous materials are those where crystals exist within the amorphous material. Furthermore, there are no particular limitations on the average crystal grain size; it can be approximately 0.1 nm to 100 nm. Additionally, there are no particular limitations on the crystal grain size caused by the Ic (integral intensity of crystallization scattering) component in XRD measurements.

[0100] The amorphization rate X can be calculated as follows: X-ray crystal structure analysis of soft magnetic metal powder is performed by XRD to identify the phase, and the peak values ​​of crystallized Fe or compounds (Ic: integrated intensity of crystalline scattering, Ia: integrated intensity of amorphous scattering) are read. The crystallization rate is calculated based on the peak intensity, and the amorphization rate X is calculated by the above (1). The calculation method will be further explained below.

[0101] For the soft magnetic metal in this embodiment, X-ray crystal structure analysis was performed using XRD to obtain the following results: Figure 1 The graph shown is used. The contour is fitted using the Lorentz function described in (2) below, resulting in the following: Figure 2 The crystalline composition pattern α shown represents the integral intensity of crystalline scattering. c α represents the amorphous composition pattern representing the integral intensity of amorphous scattering. a and the pattern α that combines them c+a The amorphization rate X is determined by the crystalline and amorphous scattering integral intensities of the obtained pattern using (1) above. The measurement range is set to the range where the diffraction angle 2θ = 30° to 60° from the amorphous halo can be confirmed. Within this range, the error between the integral intensity measured by XRD and the integral intensity calculated using the Lorentz function is kept within 1%.

[0102]

[0103] h: Peak height

[0104] u: Peak position

[0105] w: Half-width

[0106] b: Background height

[0107] There are no particular restrictions on the shape of soft magnetic alloys; they can be in powder form.

[0108] In powdered soft magnetic alloys (soft magnetic alloy powder), the corrosion potential and corrosion current density cannot be determined by the methods described above. In this embodiment, the corrosion potential and corrosion current density of the soft magnetic alloy powder satisfying 0 ≤ γ < 0.030 are the same as those of the soft magnetic alloy thin strip, which has the same composition and amorphization rate except that the oxygen content is converted to γ ​​and set to 0.003 or less. Hereinafter, the soft magnetic alloy thin strip, which has the same composition and amorphization rate except that the oxygen content is converted to γ ​​and satisfies 0 ≤ γ ≤ 0.003, will be referred to as the soft magnetic alloy thin strip for measurement.

[0109] Furthermore, within the range where oxygen content is converted to γ ​​and 0 ≤ γ < 0.030, various properties do not change significantly even with variations in oxygen content. In particular, Bs remains the same regardless of whether the soft magnetic alloy is in strip or powder form. Therefore, oxygen content can usually be converted to γ ​​and assumed to be γ = 0.

[0110] The following describes the manufacturing method of the soft magnetic alloy thin strip used for measurement.

[0111] The soft magnetic alloy strip for measurement is manufactured using the single-roll method.

[0112] First, pure substances of each element are prepared and weighed in a manner consistent with the method used to obtain a soft magnetic alloy ribbon for determining the target composition. Then, the pure substances of each element are melted to prepare a master alloy. Furthermore, there are no particular limitations on the method of melting the pure substances; for example, a method can be used where the pure substances are melted by high-frequency heating after evacuating a chamber. Additionally, the master alloy and the final soft magnetic alloy ribbon obtained for determination typically have the same composition.

[0113] Next, the prepared master alloy is heated to melt it, resulting in molten metal (liquid). The temperature of the molten metal is set at 1000–1500°C.

[0114] In the single-roller method, the thickness of the obtained soft magnetic alloy strip for measurement can be adjusted mainly by changing the rotational speed of the roll. However, the thickness of the obtained soft magnetic alloy strip for measurement can also be adjusted by, for example, by adjusting the distance between the nozzle and the roll, and the temperature of the molten metal. The thickness of the strip can be made to be 15–30 μm.

[0115] The roller temperature is maintained at 20–30°C, the roller rotation speed is 20–30 m / sec, and the atmosphere inside the chamber is atmospheric. Furthermore, the roller material is Cu.

[0116] Furthermore, by heat-treating the obtained soft magnetic alloy strip for measurement, nanocrystals can be precipitated, thus reducing the amorphization rate. By appropriately controlling the heat treatment temperature, heat treatment time, and atmosphere during heat treatment, the amorphization rate can be made to reach the target value.

[0117] The soft magnetic alloy strips used for the test were stored in an inactive atmosphere, such as Ar, at 20°C to 25°C. Furthermore, the corrosion potential and corrosion current density were measured within 24 hours of fabrication.

[0118] When the soft magnetic alloy strip used for testing is placed in an active atmosphere, or even if it is placed in an inactive atmosphere for a long time, its surface may oxidize. If the surface of the soft magnetic alloy strip used for testing oxidizes, a passivation film may sometimes form on the surface of the strip. Moreover, due to the formation of a passivation film on the surface, the corrosion potential and corrosion current density of the soft magnetic alloy strip used for testing may sometimes change. Therefore, the soft magnetic alloy strip used for testing needs to be stored in an inactive atmosphere, and its corrosion potential and corrosion current density should be measured while avoiding prolonged placement after fabrication.

[0119] Regarding soft magnetic alloy powders, the average value of the Waudelian sphericity of the particles can be 0.80 or higher. The closer the average Waudelian sphericity is to 1, the closer the shape of the particles in the soft magnetic alloy powder is to a spherical shape. Furthermore, soft magnetic alloy powders with a high average Waudelian sphericity are easier to fill when manufacturing magnetic cores, for example. Moreover, the permeability of the resulting magnetic core is easier to increase.

[0120] There are no particular limitations on the average particle size of the soft magnetic alloy powder. For example, it can be between 1 μm and 150 μm.

[0121] The average Waudelian roundness and average particle size of particles in soft magnetic alloy powders were evaluated using a Morphologi G3 (Malvern Panalytical). The Morphologi G3 is a device capable of dispersing powder in air, projecting and evaluating the shape of individual particles. Particle shapes ranging from approximately 0.5 μm to several millimeters in diameter can be evaluated using an optical microscope or laser microscope. Furthermore, with the Morphologi G3, multiple particle shapes can be projected and evaluated simultaneously.

[0122] Morphologi G3 can generate and evaluate projection maps of multiple particles simultaneously, thus enabling the evaluation of the shape of multiple particles in a shorter time compared to existing evaluation methods such as SEM observation. For example, in the experimental example described later, projection maps were generated for 20,000 particles, and the particle size and Waudelaire roundness were automatically calculated for each particle, along with the average of the average particle size and roundness. In contrast, it is difficult to evaluate the shape of multiple particles in a short time using existing SEM observation methods.

[0123] Waudel roundness is defined as the ratio of the diameter of the circle with the same projected area as the particle cross-section in the projection diagram (equivalent circle diameter) to the diameter of the circle circumscribed around the particle cross-section (equivalent circle diameter / circumscribed circle diameter).

[0124] Furthermore, the usual method for calculating particle size (particle size distribution) is based on volume. In contrast, when using Morphologi G3 to evaluate particle size (particle size distribution), both volume and number-based methods can be used to evaluate particle size (particle size distribution).

[0125] Alternatively, the average particle size of the soft magnetic alloy powder can also be determined using a particle size analyzer employing laser diffraction. In this embodiment, the particle size distribution based on volume, measured using a particle size analyzer employing laser diffraction, is defined as the average particle size.

[0126] Next, the method for making a magnetic core from magnetic powder will be explained.

[0127] Magnetic cores can be obtained by molding magnetic powder. There are no particular limitations on the molding method. As an example, a method for obtaining a magnetic core by pressure molding will be explained.

[0128] First, the magnetic powder and resin are mixed. By mixing the resin, a high-strength molded part can be easily obtained by pressure molding. There are no particular restrictions on the type of resin. Examples include phenolic resin and epoxy resin. There are also no particular restrictions on the amount of resin added. When adding resin, it can be added at a rate of 1% to 5% by mass relative to the magnetic powder.

[0129] The mixture of magnetic powder and resin is granulated to obtain granulated powder. There are no particular limitations on the granulation method. For example, a mixer can be used for granulation. There are no particular limitations on the particle size of the granulated powder.

[0130] The obtained granulated powder is pressed into a molded body. There are no particular limitations on the molding pressure. For example, a surface pressure of 1 ton / cm² can be used. 2 Above 10 tons / cm 2 The higher the molding pressure, the easier it is to increase the relative permeability of the resulting magnetic core. However, when the particle size distribution of the magnetic powder is wide, even if the molding pressure is lower than that in typical pressure molding, the relative permeability of the resulting magnetic core can still be increased. This is because the resulting magnetic core is easier to densify.

[0131] Furthermore, the resin contained in the molded body can be cured to obtain a magnetic core. There are no particular restrictions on the curing method. Heat treatment can be performed under conditions where the resin used can cure.

[0132] Next, the evaluation method for the Woddell roundness of the magnetic core will be explained.

[0133] The particle size distribution and Waudelaire roundness of the magnetic powder particles contained in the magnetic core can be determined by SEM observation. Specifically, the Heywood diameter and Waudelaire roundness of each magnetic powder particle contained in any cross-section of the magnetic core can be calculated based on the SEM image. There is no particular limitation on the magnification of the SEM observation, as long as the particle size of the magnetic powder particles can be determined. In addition, there is no particular limitation on the size of the SEM observation range, which is set to include at least 10, preferably more than 100, and more preferably more than 500 magnetic powder particles. The number of magnetic powder particles contained in the observation range should be at least 100 if possible. By setting multiple observation ranges from multiple cross-sections, the total number of magnetic powder particles contained in the observation range can be at least 100.

[0134] Regarding the Waudelian roundness of the magnetic powder particles contained in the magnetic core, let S be the area of ​​the magnetic powder particle on the cross section, and let L be the length around the magnetic powder particle, with 2×(π×S). 1 / 2 / L is used to represent it.

[0135] Composition maps based on EDS (Energy Dispersive X-ray Analysis) were obtained when magnetic powder particles of various compositions were mixed in the magnetic core. The composition of the magnetic powder particles was determined using the composition maps. Then, only the magnetic powder particles with compositions that yielded the average value for calculating the Wardell roundness were extracted, and the Wardell roundness was determined.

[0136] The average value of the Woddell roundness of soft magnetic alloy powders measured using Morphologi G3 is approximately consistent with the average value of the Woddell roundness of magnetic powder particles extracted from arbitrary sections of the magnetic core.

[0137] The Bs of the soft magnetic alloy powder contained in a magnetic core, where soft magnetic alloy powder is mixed with resin components, is sometimes difficult to determine. However, even in such cases, it is possible to determine the Bs of the soft magnetic alloy powder contained in the magnetic core by fabricating a thin strip of soft magnetic alloy for measurement and measuring the Bs.

[0138] The corrosion potential and corrosion current density of the soft magnetic alloy powder in a magnetic core, which is a mixture of soft magnetic alloy powder and resin components, can be determined by fabricating a soft magnetic alloy thin strip for measurement.

[0139] There are no particular limitations on the methods used to determine the composition of soft magnetic alloys. For example, ICP (Inductively Coupled Plasma) can be used. Additionally, if it is difficult to determine the oxygen content using ICP, a pulsed heating melting extraction method can be used. If it is difficult to determine the carbon and sulfur content using ICP, an infrared absorption method can be used.

[0140] For magnetic cores containing a mixture of soft magnetic alloy powder and resin components, it is sometimes difficult to confirm the composition of the soft magnetic alloy using methods such as ICP as described above. In such cases, the composition can sometimes be confirmed using EDS (Energy Dispersive X-ray) analysis or EPMA (Electron Probe Microanalysis) analysis. However, detailed composition is sometimes difficult to confirm using EDS or EPMA analysis. For example, the resin components in the magnetic core may affect the measurement. Additionally, in cases where the magnetic core requires processing, the processing itself may affect the measurement.

[0141] In cases where detailed composition cannot be determined using methods such as ICP, pulsed heating melt extraction, and EDS, 3DAP (three-dimensional atomic probe microanalysis) can be used to confirm the composition. When using 3DAP, the influence of resin components or surface oxidation can be eliminated in the area being analyzed, allowing for the determination of the composition of soft magnetic alloys, i.e., soft magnetic alloy powders. This is because a small region, such as Φ20nm×100nm, can be established within the soft magnetic alloy powder, and the average composition can be measured. Furthermore, if 3DAP determination is feasible, a soft magnetic thin strip can be fabricated using only the composition determined by 3DAP, allowing for the measurement of Bs, corrosion potential, and corrosion current density.

[0142] There are no particular limitations on the methods for confirming the degree of amorphization of soft magnetic alloys. Typically, as mentioned above, X-ray crystal structure analysis is performed using XRD. However, XRD is difficult to perform in magnetic cores where soft magnetic alloy powder is mixed with resin components. In cases where XRD is difficult to perform, EBSD (Empirical Orientation Determination) can be used to determine the degree of amorphization. Alternatively, the degree of amorphization can be calculated by analyzing the intensity of diffraction points using a selected area electron diffraction pattern obtained with a wide field of view from Φ100 nm to Φ several μm using transmission electron microscopy (TEM).

[0143] The manufacturing method of the soft magnetic alloy of this embodiment will be described below.

[0144] The manufacturing method of the soft magnetic alloy in this embodiment is not particularly limited. For example, there is a method for manufacturing a thin strip of the soft magnetic alloy of this embodiment using a single-roll method. In addition, the thin strip may also be a continuous thin strip.

[0145] In the single-roller process, firstly, pure substances containing each element of the final soft magnetic alloy are prepared and weighed to achieve the same composition as the final soft magnetic alloy. Then, the pure substances of each element are melted to create a master alloy. Furthermore, there are no particular limitations on the melting method of the pure metals; for example, a method involving high-frequency heating after evacuating a chamber can be used to melt them. Additionally, the master alloy and the final soft magnetic alloy typically have the same composition.

[0146] Next, the prepared master alloy is heated and melted to obtain molten metal (liquid). There are no particular restrictions on the temperature of the molten metal; for example, it can be set to 1000–1500°C.

[0147] In the single-roll method, the thickness of the resulting strip can be adjusted primarily by changing the rotational speed of the roll. However, the thickness can also be adjusted by factors such as the distance between the nozzle and the roll, and the temperature of the molten metal. There are no particular limitations on the thickness of the strip; for example, it can be set to 15–30 μm.

[0148] There are no particular limitations on the temperature, rotational speed, and atmosphere inside the chamber of the roller. Setting the roller temperature to 20–30°C facilitates the fabrication of an amorphous structure, and is therefore preferred. There is a tendency for the average initial crystallite size to decrease as the roller rotational speed increases. Furthermore, by setting the speed to 20–30 m / sec, it is easy to obtain a soft magnetic alloy strip with an amorphous structure. Considering cost, it is preferable to maintain an atmospheric atmosphere inside the chamber.

[0149] Furthermore, by heat-treating soft magnetic alloys with an amorphous structure, nanocrystals can be generated, reducing the amorphization rate X. There are no particular restrictions on the atmosphere during heat treatment. It can also be carried out in a vacuum or in an inactive atmosphere such as Ar gas.

[0150] In addition to the single-roller method described above, other methods for obtaining the soft magnetic alloy powder of this embodiment include, for example, water atomization or gas atomization. The gas atomization method will be described below.

[0151] In the gas atomization method, similar to the single-roller method described above, a molten alloy at 1000–1500°C is obtained. This molten alloy is then sprayed into a chamber to produce powder. Specifically, when the molten master alloy is sprayed from the nozzle towards the cooling section inside the cylinder, high-pressure gas is sprayed towards the sprayed molten droplets. The droplets solidify by colliding with the cooling section (cooling water), becoming a soft magnetic alloy powder. By varying the amount of molten droplets during powder production, the amorphization rate X can be changed. There is a tendency that the more molten droplets are produced, the lower the amorphization rate X becomes.

[0152] Furthermore, the amorphization rate X can be reduced by heat-treating soft magnetic alloy powder with an amorphous structure to generate nanocrystals. There are no particular restrictions on the atmosphere during heat treatment. It can also be carried out in a vacuum or in an inactive atmosphere such as Ar gas.

[0153] In gas atomization, manganese (Mn) can also be added after the molten metal is obtained. Adding Mn after obtaining the molten metal facilitates the full utilization of its deoxidizing effect. Furthermore, it easily reduces the viscosity of the molten metal. The lower the viscosity of the molten metal, the easier it is to increase the average value of the Waudel roundness.

[0154] By changing the oxygen concentration in the injected gas, the oxygen content of the resulting soft magnetic alloy powder can be altered. Furthermore, there are no particular limitations on the type of injected gas; examples include N2 gas and Ar gas.

[0155] Furthermore, even if the soft magnetic alloy strip is crushed into soft magnetic alloy powder, it is difficult to achieve an average Wodel roundness of 0.80 or higher.

[0156] The above describes one embodiment of the present invention, but the present invention is not limited to the above embodiment.

[0157] The shape of the soft magnetic alloy in this embodiment is not particularly limited. As described above, strip shapes and powder shapes are examples, but in addition to these, block shapes and the like can also be considered.

[0158] The application of the soft magnetic alloy in this embodiment is not particularly limited. For example, magnetic components can be used, among which, in particular, magnetic cores and inductors can be listed.

[0159] In particular, when using soft magnetic alloy powder with an amorphization rate of 85% or higher to make the magnetic core, it is possible to obtain a magnetic core with relatively high permeability and low iron loss.

[0160] Example

[0161] The present invention will now be described in detail based on embodiments.

[0162] (Experimental Example 1)

[0163] Raw material metals were weighed in such a way that they became the alloy compositions of the various embodiments and comparative examples shown in Tables 1 to 12, and melted by high-frequency heating to produce a master alloy.

[0164] The prepared master alloy is then heated and melted to a molten state at 1300°C. This molten metal is then sprayed onto a roller at 25 m / sec using a 30°C roller in the atmosphere to produce a thin strip. The strip has a thickness of 20–25 μm, a width of approximately 5 mm, and a length of approximately 10 m. The single roller is made of Cu.

[0165] Samples 625, 627, and 629 in Table 10 were heat-treated to precipitate nanocrystals with a grain size of less than 30 nm, thereby reducing the amorphization rate X to 10%. Specifically, the heat treatment was carried out at 400–650 °C for 10–60 minutes.

[0166] X-ray diffraction was performed on each obtained thin band to determine the amorphization rate (X). When the amorphization rate (X) was above 85%, the material was considered amorphous. When the amorphization rate (X) was below 85% and the average crystal grain size was less than 30 nm, the material was considered nanocrystalline. When the amorphization rate (X) was below 85% and the average crystal grain size was greater than 30 nm, the material was considered crystalline. The results are recorded in the respective tables.

[0167] ICP analysis confirmed that the composition of the master alloy was roughly the same as that of the thin strip.

[0168] <Saturation magnetic flux density Bs>

[0169] Bs was measured for each thin strip. A vibrating sample magnetometer (VSM) was used to measure Bs at a magnetic field of 1000 kA / m. A Bs value of 1.50 T or higher was considered good.

[0170] <Corrosion potential Ecorr and corrosion current density icorr>

[0171] After processing each thin strip, it was immersed in an aqueous NaCl solution and measured using the method described above. Furthermore, for each thin strip, a strip with a thickness of 20–25 μm and a width of approximately 5 mm was used. The length was appropriately processed such that the portion immersed in the NaCl aqueous solution had a thickness of 20–25 μm, a width of approximately 5 mm, and a length of approximately 10 mm. The thickness of the strip was measured using a micrometer, and the width and length were measured using a digital microscope. The surface area of ​​the portion immersed in the NaCl aqueous solution was calculated. A corrosion potential above -630 mV was considered good, and a corrosion current density of 45 μA / cm² was used. 2 The following conditions are set as good.

[0172] [Table 1A]

[0173]

[0174] [Table 1B]

[0175]

[0176] [Table 1C]

[0177]

[0178] [Table 1D]

[0179]

[0180] [Table 1E]

[0181]

[0182] [Table 1F]

[0183]

[0184] [Table 1G]

[0185]

[0186] [Table 1H]

[0187]

[0188] [Table 1I]

[0189]

[0190] [Table 1J]

[0191]

[0192] [Table 1K]

[0193]

[0194] [Table 1L]

[0195]

[0196] [Table 1M]

[0197]

[0198] Tables 1A to 1M were performed under the same conditions, except that the Co content (α) and Mn content (f) relative to Fe were varied. When α and f were within the specified ranges, Bs and corrosion resistance were good. Conversely, when α was too small and the Mn content was outside the specified range, corrosion resistance decreased. Furthermore, when α was too large, Bs decreased. Moreover, when the Mn content was too large, crystallization occurred in the soft magnetic alloy ribbon, and the amorphization rate X was less than 85%.

[0199] [Table 2A]

[0200]

[0201] [Table 2B]

[0202]

[0203] [Table 3A]

[0204]

[0205] [Table 3B]

[0206]

[0207] [Table 4A]

[0208]

[0209] [Table 4B]

[0210]

[0211] [Table 5A]

[0212]

[0213] [Table 5B]

[0214]

[0215] [Table 6A]

[0216]

[0217] [Table 6B]

[0218]

[0219] [Table 6C]

[0220]

[0221] Tables 2A and 2B record experimental examples of varying Cr content (e); Tables 3A and 3B record experimental examples of varying P content (b); Tables 4A and 4B record experimental examples of varying C content (d); Tables 5A and 5B record experimental examples of varying Si content (c); and Tables 6A, 6B, and 6C record experimental examples of varying B content (a). When the content of each component is within the specified range, Bs exhibits good corrosion resistance.

[0222] In Tables 2A and 2B, particularly when 0.001 ≤ e ≤ 0.020 and 1.00 ≤ α(1-γ){1-(a+b+c+d+e)}×e×10000 ≤ 50.0, good corrosion resistance is maintained, and a high Bs is obtained. Conversely, when α is too small, corrosion resistance decreases; when α is too large, Bs decreases. Furthermore, when e is too large, Bs also decreases.

[0223] In Tables 3A and 3B, good corrosion resistance is maintained, and a high Bs is obtained, especially when 0 ≤ b ≤ 0.050. Furthermore, when b is above 0.001, corrosion resistance is higher compared to when b is 0.000; and when b is below 0.050, a higher Bs is obtained compared to when b exceeds 0.050. Conversely, when b is too large, Bs decreases.

[0224] In Tables 4A and 4B, Bs decreases when d is too large.

[0225] In Tables 5A and 5B, Bs decreases when c is too large.

[0226] In Tables 6A, 6B, and 6C, when 'a' is too small, crystallization occurs in the soft magnetic alloy strip, the amorphization rate X is less than 85%, and the corrosion resistance decreases. When 'a' is too large, Bs decreases.

[0227] [Table 7A]

[0228]

[0229] [Table 7B]

[0230]

[0231] [Table 7C]

[0232]

[0233] [Table 7D]

[0234]

[0235] [Table 7E]

[0236]

[0237] [Table 7F]

[0238]

[0239] [Table 7G]

[0240]

[0241] [Table 7H]

[0242]

[0243] [Table 7I]

[0244]

[0245] [Table 7J]

[0246]

[0247] [Table 7K]

[0248]

[0249] [Table 7L]

[0250]

[0251] [Table 7M]

[0252]

[0253] Tables 7A to 7M differ from Tables 1A to 1M in that they vary the content of Co (α) and Mn (f) relative to Fe in compositions that do not contain P and Cr. When α and f are within specified ranges, Bs and corrosion resistance are good. Conversely, when α is too small and the Mn content is outside the specified range, corrosion resistance decreases. Furthermore, when α is too large, Bs decreases. Moreover, when the Mn content is too large, crystallization occurs in the soft magnetic alloy ribbon, and the amorphization rate X is less than 85%.

[0254] [Table 8]

[0255]

[0256] Table 8 records the results for sample 173, where a portion of the Fe was replaced with Ni. With the addition of a small amount of Ni, there is a trend towards increased Bs compared to the case without Ni. Furthermore, a larger β indicates improved corrosion resistance, but with excessively large β, Bs decreases.

[0257] [Table 9A]

[0258]

[0259] [Table 9B]

[0260]

[0261] [Table 9C]

[0262]

[0263] [Table 9D]

[0264]

[0265] Tables 9A to 9D describe the specimens for which a portion of Fe was replaced with X1 for specimen number 173. When X1 is present within a specified range, i.e., when γ is within a specific range, high corrosion resistance and high Bs are observed.

[0266] [Table 10]

[0267]

[0268] Table 10 records the results of two samples with and without heat treatment for γ = 0, 0.037, and 0.085. Reducing the amorphization rate X increases Bs, but decreases corrosion resistance. Furthermore, when γ is too large, Bs and / or corrosion resistance decrease.

[0269] (Experimental Example 2)

[0270] Raw material metals were weighed in such a manner that they would form the alloy compositions of the various embodiments and comparative examples shown in Tables 1 to 10, and melted by high-frequency heating to prepare a master alloy. In this case, raw materials other than Mn were first melted to obtain a molten alloy, and then Mn was added to melt it.

[0271] The prepared master alloy is heated and melted to form a molten metal at 1500°C. Then, soft magnetic alloy powders with the alloy composition of each sample are produced by gas atomization. Specifically, when the molten master alloy is ejected from the nozzle towards the cooling section inside the cylinder, a high-pressure gas is injected towards the ejected molten metal. The high-pressure gas is N2 gas. The molten metal is cooled and solidified by colliding with the cooling section (cooling water) to form soft magnetic alloy powder. Furthermore, the gas atomization conditions are appropriately controlled to obtain soft magnetic alloy powders with the average particle size and Waudel roundness values ​​listed in Tables 1 to 10. Specifically, the ejection rate of molten metal is varied within the range of 0.5–4 kg / min, the gas injection pressure is 2–10 MPa, and the cooling water pressure is 7–19 MPa.

[0272] ICP analysis confirmed that the composition of the master alloy was roughly consistent with that of the powder.

[0273] X-ray diffraction was performed on each obtained powder to determine the amorphization rate X. When the amorphization rate X was 85% or higher, it was considered to be composed of amorphous material; when the amorphization rate X was less than 85% and the average crystal grain size was less than 30 nm, it was considered to be composed of nanocrystals; when the amorphization rate X was less than 85% and the average crystal grain size was greater than 30 nm, it was considered to be composed of crystals. Furthermore, the crystal structure was completely identical in both Experimental Example 1 (thin ribbon) and Experimental Example 2 (powder).

[0274] The average particle size and average Wardell roundness of the obtained soft magnetic alloy powder were determined using the methods described above. Furthermore, ICP analysis confirmed that the composition of the master alloy was consistent with that of the powder.

[0275] Tables 1A to 1M were performed under the same conditions, except that the Co content (α) and Mn content (f) relative to Fe were varied. Including the examples described in Tables 2 to 12, when α and f were within specified ranges, Bs and corrosion resistance were good. Furthermore, the average value of the Wardell roundness was 0.80 or higher. Conversely, when α was too small and the Mn content was outside the specified range, corrosion resistance decreased. Additionally, when α was too large, Bs decreased. Furthermore, when the Co content was within the specified range and the Mn content was too small, the average value of the Wardell roundness decreased. When the Mn content was too large, crystallization occurred in the soft magnetic alloy powder, and the amorphization rate X was less than 85%.

[0276] (Experimental Example 3)

[0277] In Experimental Example 3, a toroidal magnetic core was fabricated using soft magnetic alloy powder with the compositions shown in Tables 11 and 12. Table 11 lists samples in which the value of α and / or average particle size varied with the presence of P and Cr, and samples in which the value of α and / or average particle size varied without P and Cr. Table 12 lists samples in which the amorphization rate X varied by changing the amount of molten metal dropped. Furthermore, the examples in Table 11 and the examples in Table 12 with 100% amorphization rate were all examples using the soft magnetic alloy powder prepared in Experimental Example 2. The sample numbers used were the same as those in Experimental Example 2.

[0278] The Bs of the soft magnetic alloy powders in the examples of Tables 11 and 12 were confirmed to be good. Furthermore, the soft magnetic alloy powders of the examples in Tables 11 and 12 were visually confirmed to be a gray metallic color. This also confirms that the soft magnetic alloy powders of the examples in Tables 11 and 12 have good corrosion resistance. In contrast, the soft magnetic alloy powders of the comparative examples in Tables 11 and 12 were visually confirmed to be reddish-brown. This also confirms that the soft magnetic alloy powders of the comparative examples have poor corrosion resistance.

[0279] The following describes the method for fabricating the toroidal magnetic core in this experimental example. First, soft magnetic alloy powder and resin (phenolic resin) are mixed. The resin is mixed such that its mass percentage relative to the soft magnetic alloy powder reaches 2%. Next, using a standard planetary mixer as a stirrer, the mixture is granulated into powder with a particle size of approximately 500 μm. Then, the resulting granulated powder is press-molded to create its shape. inner diameter A ring-shaped molded body with a height of 6.0 mm. (2 tons / cm) 2 (192MPa)~10ton / cm 2 The surface pressure was adjusted within the range of 980 MPa to achieve a filling rate of approximately 72-73%. The resulting molded body was cured at 150°C to fabricate a toroidal magnetic core. Only the required number of toroidal magnetic cores were fabricated for the experiments described later.

[0280] <Fill Rate>

[0281] The density of each toroidal core is calculated based on its size and mass. Then, the fill power (relative density) is calculated by dividing the calculated density of the toroidal core by the true density, which is the density calculated based on the mass ratio of the soft magnetic alloy powder.

[0282] <Relative permeability>

[0283] For each toroidal core, the measurement was performed using a winding wire with 12 turns and an LCR meter (HP LCR428A) at a measurement frequency of 100 kHz.

[0284] <Iron Loss>

[0285] For each toroidal core, 20 primary windings and 14 secondary windings were wound. Then, the iron loss was measured at 300 kHz, 50 mT, and 20–25 °C using a B-H analyzer (SY-8232 manufactured by Iwasaki Telecommunications Co., Ltd.).

[0286] [Table 11]

[0287]

[0288] [Table 12]

[0289]

[0290] As shown in Table 11, when using soft magnetic alloy powder with α and other compositions within the specified range to fabricate toroidal cores, a higher relative permeability is observed compared to comparative examples with excessively small α. Furthermore, there is a trend towards larger average particle size leading to greater iron loss.

[0291] As shown in Table 12, when the amorphization rate X is above 85%, compared with the case where X is below 85%, the result is a relatively high magnetic permeability and low iron loss.

[0292] In Tables 1 to 12, the oxygen content was converted to γ ​​and the composition was recorded as γ = 0. In fact, converting the oxygen content to γ ​​also satisfies 0 ≤ γ < 0.030. The Bs values ​​are identical between the soft magnetic alloy strips recorded in Tables 1 to 12 and the soft magnetic alloy powders with the same composition. Therefore, all the soft magnetic alloy strips recorded in Tables 1 to 12 are considered as soft magnetic alloy strips for measuring soft magnetic alloy powders with the same composition. When the corrosion potential and corrosion current density of the soft magnetic alloy strips for measurement are good, the soft magnetic alloy powder of the examples with the same composition is confirmed to be a gray metallic color by visual inspection. Conversely, when the corrosion potential and corrosion current density of the soft magnetic alloy strips for measurement are poor, the soft magnetic alloy powder of the comparative examples with the same composition is confirmed to be reddish-brown by visual inspection. This also confirms that the corrosion resistance of the soft magnetic alloy powder of the comparative examples is poor.

[0293] (Experimental Example 4)

[0294] In Experiment 4, a soft magnetic alloy powder with the composition described in Table 13 was prepared. At this time, the oxygen content of the obtained soft magnetic alloy powder was varied by changing the oxygen concentration in the injected gas to the values ​​shown in Table 13, thus changing γ. Furthermore, as in Experiment 3, a toroidal magnetic core was prepared. The results are shown in Table 13.

[0295] [Table 13]

[0296]

[0297] The Bs values ​​of both the examples and comparative examples in Table 13 are good. Furthermore, the soft magnetic alloy powder of the examples in Table 13 is visually confirmed to be a gray metallic color. This also confirms the good corrosion resistance of the soft magnetic alloy powder of the examples in Table 13. In contrast, the soft magnetic alloy powder of the comparative examples with excessively high γ is visually confirmed to be reddish-brown.

[0298] Furthermore, when using the soft magnetic alloy powder of each embodiment that satisfies 0≤γ<0.030 to form a toroidal core, it has a higher relative permeability and lower iron loss compared to the case of using the soft magnetic alloy powder of each embodiment that satisfies γ≥0.030 to form a toroidal core with the same fill rate.

[0299] (Experimental Example 5)

[0300] In Experimental Example 5, the composition of the soft magnetic alloy powder contained in the toroidal core of the embodiment in Table 13 was confirmed by 3DAP, and a soft magnetic alloy thin strip was fabricated. The Bs, corrosion potential, and corrosion current density of the fabricated soft magnetic alloy thin strip were measured. The results are shown in Table 14.

[0301] [Table 14]

[0302]

[0303] As can be seen from Table 14, the soft magnetic alloy strips of each embodiment have good Bs, corrosion potential and corrosion current density.

[0304] As shown in Table 14, for soft magnetic alloy powders prepared by converting the oxygen content to γ ​​and varying it within the range of 0 ≤ γ < 0.030, when the composition was confirmed by 3DAP and soft magnetic alloy ribbons with the same composition were prepared, the corrosion potential and corrosion current density of the prepared soft magnetic alloy ribbons did not change significantly. Furthermore, when the oxygen content of the soft magnetic alloy powder was converted to γ ​​and varied within the range of 0 ≤ γ ≤ 0.003 to prepare soft magnetic alloy ribbons for testing, the corrosion potential and corrosion current density of the prepared soft magnetic alloy ribbons did not change at all.

[0305] The above confirms that the soft magnetic alloy strips used for determining the corrosion potential and corrosion current density of soft magnetic alloy powders with oxygen content converted to γ ​​and satisfying 0 ≤ γ < 0.030 can be considered as having the same composition, except that the oxygen content is converted to γ ​​and satisfies 0 ≤ γ ≤ 0.003. Further, within the oxygen content range of 0 ≤ γ ≤ 0.003, the corrosion potential and corrosion current density of the soft magnetic alloy strips do not change. Therefore, it is confirmed that the corrosion potential and corrosion current density of soft magnetic alloy powders, which are difficult to measure directly, can be determined using soft magnetic alloy strips with an oxygen content of 0 ≤ γ ≤ 0.003. It is also confirmed that, as with the samples recorded in Tables 1 to 12, even if considered as oxygen-free when the oxygen content is converted to γ ​​and satisfies 0 ≤ γ < 0.030, there is generally no problem.

Claims

1. A soft magnetic alloy containing a composition of the formula ((Fe) (1－(α+β)) Co α Ni β ) 1－γ X1 γ ) (1－(a+b+c+d+e)) B a P b Si c C d Cr e The composition of the components (atomic ratio) and Mn is characterized by: X1 is selected from one or more of the following elements: Ti, Zr, Hf, Nb, Ta, Mo, W, Al, Ga, Ag, Zn, S, Ca, Mg, V, Sn, As, Sb, Bi, N, O, Au, Cu, rare earth elements, and platinum group elements. 0.020≤a≤0.200， 0≤b≤0.070， 0≤c≤0.100， 0≤d≤0.050， 0≤e≤0.040， 0.005≤α≤0.700， 0≤β≤0.200， 0 ≤ γ < 0.030, 0.720≤1-(a+b+c+d+e)≤0.900, When the Mn content is set as f (at%), 0.002 ≤ f < 3.

0. In a 0.5 mol / L NaCl aqueous solution, the spontaneous potential was set as the reference potential, the measurement potential range was set to -0.3 V to 0.3 V, and the potential scan rate was set to 0.833 mV / s. Based on the potential and current values ​​measured by the LSV method, the corrosion potential calculated by Tafel extrapolation was between -630 mV and -50 mV, and the corrosion current density was 0.3 μA / cm². 2 Above 45μA / cm 2 the following.

2. The soft magnetic alloy as described in claim 1, characterized in that: 0.003≤f / α(1-γ){1-(a+b+c+d+e)}≤710.

3. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0.050≤α≤0.600。 4. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0.100≤α≤0.500 and 0.050≤f / α(1-γ){1-(a+b+c+d+e)}≤8.

0.

5. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0.001≤e≤0.020 and 1.00≤α(1-γ){1-(a+b+c+d+e)}×e×10000≤50.

0.

6. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0≤b≤0.050。 7. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0.780≤1-(a+b+c+d+e)≤0.

890.

8. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0.001≤β≤0.050。 9. The soft magnetic alloy as described in claim 1 or 2, characterized in that: 0 < γ < 0.

030.

10. The soft magnetic alloy as described in claim 1 or 2, characterized in that: The amorphization rate X shown in (1) below is 85% or higher. X=100-(Ic / (Ic+Ia)×100)…(1) Ic: Integral intensity of crystalline scattering Ia: Integral intensity of amorphous scattering.

11. The soft magnetic alloy as described in claim 1 or 2, characterized in that: It is in powder form.

12. The soft magnetic alloy as described in claim 11, characterized in that: The average Wodell roundness of the powder particles contained in the powder-shaped soft magnetic alloy is greater than 0.

80.

13. A magnetic component, characterized in that: Includes the soft magnetic alloy according to any one of claims 1 to 12.

Images