Nanocrystalline alloy soft magnetic powder, powder magnetic core, magnetic element, and electronic device

Abstract

Provided are: a nanocrystal alloy soft magnetic powder which optimizes the particle shape and particle size distribution and exhibits good filling properties and magnetic properties; a dust core which contains the powder and has high magnetic permeability and low iron loss; a magnetic element; and an electronic device. The nanocrystal alloy soft magnetic powder is represented by the composition formula FeaCubNbc (Si1-x (B1-yCry) x) 100-a-b-c-dSd [a, b, c, d, x, and y satisfy 75.5 < = a < = 79.5, 0.3 < = b < = 2.0, 2.0 < = c < = 4.0, 0.001 < = d < = 0.080, 0.55 < = x < = 0.91, and 0 < = y < = 0.185, expressed in atomic ratio. [1, 2, 3], and an impurity composition, and contains crystal grains of 1.0 nm to 30.0 nm, a particle size D10 of 7.0 [mu] m to 15.0 [mu] m, and a particle size D50 of 22.0 [mu] m to 32.0 [mu] m.

Description

Technical Field

[0001] This invention relates to nanocrystalline alloy soft magnetic powder, pressed magnetic core, magnetic components, and electronic devices. Background Technology

[0002] Patent Document 1 discloses an amorphous soft magnetic powder, characterized in that the amorphous soft magnetic powder contains 0.01% to 0.2% by mass of sulfur (S), and the composition other than S is given by the formula: (Fe 1-a TM a ) 100-w-x-y-z P w B x L y Si z (wherein, unavoidable impurities are included, TM is one or more elements selected from Co and Ni, L is one or more elements selected from Al, V, Cr, Y, Zr, Mo, Nb, Ta, and W, 0≤a≤0.98, 2≤w≤16 atomic%, 2≤x≤16 atomic%, 0<y≤10 atomic%, 0≤z≤8 atomic%). Furthermore, a powder with a particle size D50 of approximately 10 μm is obtained via water atomization. Based on this configuration, an amorphous soft magnetic powder with good magnetic properties and capable of high-density forming under low pressure can be provided.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2011-023673.

[0006] However, in the amorphous soft magnetic powder described in Patent Document 1, the particle size distribution is located on the small diameter side, resulting in poor filling performance. Therefore, from the viewpoint of improving the filling performance, there is still room for improvement in the amorphous soft magnetic powder described in Patent Document 1.

[0007] Therefore, there is a need for nanocrystalline alloy soft magnetic powders that optimize particle shape and size distribution and exhibit good filling properties and magnetic properties. Summary of the Invention

[0008] The nanocrystalline alloy soft magnetic powder involved in the application examples of this invention is composed of Fe, expressed in atomic ratios. a Cu b Nb c (Si 1-x (B 1-y Cr y ) x ) 100-a-b-c-d S d

[0009] [a, b, c, d, x, y satisfy]

[0010] 75.5≤a≤79.5,

[0011] 0.3≤b≤2.0,

[0012] 2.0≤c≤4.0,

[0013] 0.001≤d≤0.080,

[0014] 0.55≤x≤0.91,

[0015] 0 ≤ y ≤ 0.185.

[0016] The composition and impurities,

[0017] The nanocrystalline alloy soft magnetic powder contains crystallites with a diameter of 1.0 nm or more and 30.0 nm or less, as determined by X-ray diffraction.

[0018] In the cumulative particle size distribution under volume reference obtained using a laser diffraction particle size distribution measuring device, when the particle size at which the cumulative frequency reaches 10% from the small diameter side is defined as D10, and the particle size at which the cumulative frequency reaches 50% from the small diameter side is defined as D50,

[0019] The particle size D10 is greater than 7.0 μm and less than 15.0 μm.

[0020] The particle size D50 is greater than 22.0 μm and less than 32.0 μm.

[0021] The pressed powder magnetic core involved in the application examples of the present invention includes the nanocrystalline alloy soft magnetic powder involved in the application examples of the present invention.

[0022] The magnetic element involved in the application example of the present invention has the powder core involved in the application example of the present invention.

[0023] The electronic device described in the application examples of the present invention includes the magnetic element described in the application examples of the present invention. Attached Figure Description

[0024] Figure 1 This is a schematic top view showing a ring-shaped coil component.

[0025] Figure 2 It is a schematic perspective view of a coil component with a closed magnetic circuit.

[0026] Figure 3 This is a perspective view of a mobile personal computer, which is an electronic device according to an embodiment.

[0027] Figure 4 This is a top view showing a smartphone, which is an electronic device involved in the implementation.

[0028] Figure 5 This is a perspective view showing a digital still camera as an electronic device according to an embodiment.

[0029] Figure 6 Table 1 shows the composition of the nanocrystalline alloy soft magnetic powders of samples No.1 to 15.

[0030] Figure 7 Table 2 shows the composition of the nanocrystalline alloy soft magnetic powders of samples No. 16-30.

[0031] Figure 8 Table 3 shows the evaluation results of the nanocrystalline alloy soft magnetic powders of samples No.1 to No.15.

[0032] Figure 9 Table 4 shows the evaluation results of the nanocrystalline alloy soft magnetic powders of samples No. 16 to 30.

[0033] Explanation of reference numerals in the attached figures

[0034] 10: Coil component; 11: Powder core; 12: Wire; 20: Coil component; 21: Powder core; 22: Wire; 100: Display unit; 1000: Magnetic element; 1100: Personal computer; 1102: Keyboard; 1104: Main body; 1106: Display unit; 1200: Smartphone; 1202: Operation button; 1204: Earpiece; 1206: Microphone; 1300: Digital still camera; 1302: Housing; 1304: Light receiving unit; 1306: Shutter button; 1308: Memory. Detailed Implementation

[0035] Below, based on the preferred embodiments shown in the accompanying drawings, the nanocrystalline alloy soft magnetic powder, pressed magnetic core, magnetic element, and electronic device involved in the present invention will be described in detail.

[0036] 1. Nanocrystalline alloy soft magnetic powder

[0037] The nanocrystalline alloy soft magnetic powder involved in the embodiments is a metal powder exhibiting soft magnetism. The aforementioned nanocrystalline alloy soft magnetic powder can also be applied to any purpose, for example, the particles can be bonded together with an adhesive to manufacture various pressed powder materials such as pressed magnetic cores and electromagnetic wave absorbing materials.

[0038] The nanocrystalline alloy soft magnetic powder involved in the embodiments is composed of Fe, expressed in atomic ratios. a Cu b Nb c(Si 1-x (B 1-y Cr y ) x ) 100-a-b-c-d S d

[0039] [a, b, c, d, x, y satisfy]

[0040] 75.5≤a≤79.5,

[0041] 0.3≤b≤2.0,

[0042] 2.0≤c≤4.0,

[0043] 0.001≤d≤0.080,

[0044] 0.55≤x≤0.91,

[0045] 0 ≤ y ≤ 0.185.

[0046] The composition and impurities.

[0047] Furthermore, the nanocrystalline alloy soft magnetic powder involved in the embodiments has a crystallite diameter (meaning a tiny single crystal) of 1.0 nm or more and 30.0 nm or less as determined by X-ray diffraction, including crystallites with so-called nanoscale crystallite diameters.

[0048] Furthermore, in the cumulative particle size distribution of the nanocrystalline alloy soft magnetic powder involved in the embodiment, based on volume, obtained using a laser diffraction particle size distribution measuring device, when the particle size at 10% of the cumulative frequency from the small diameter side is defined as D10 and the particle size at 50% of the cumulative frequency from the small diameter side is defined as D50, the particle size D10 is 7.0 μm or more and 15.0 μm or less, and the particle size D50 is 22.0 μm or more and 32.0 μm or less.

[0049] In such nanocrystalline alloy soft magnetic powder, the optimal amount of sulfur (S) allows for the optimization of particle shape and size distribution. This results in a nanocrystalline alloy soft magnetic powder exhibiting excellent filling properties. Furthermore, the optimized content of each element, crystallite diameter, particle size D10, and particle size D50 in the aforementioned nanocrystalline alloy soft magnetic powder ensure good magnetic properties such as low coercivity and high permeability. Therefore, by incorporating such nanocrystalline alloy soft magnetic powder, a powder-pressed magnetic core capable of achieving high permeability and low iron loss in magnetic components can be obtained.

[0050] The following is a detailed description of the nanocrystalline alloy soft magnetic powder involved in the embodiments.

[0051] 1.1. Composition

[0052] Fe (iron) has a significant impact on the basic magnetic and mechanical properties of the nanocrystalline alloy soft magnetic powder involved in the implementation method.

[0053] The Fe content 'a' is 75.5 atomic% or more and 79.5 atomic% or less, preferably 76.0 atomic% or more and 79.0 atomic% or less, and more preferably 76.5 atomic% or more and 78.5 atomic% or less. Furthermore, if the Fe content 'a' is below the lower limit, the saturation magnetic flux density and permeability of the nanocrystalline alloy soft magnetic powder decrease. On the other hand, if the Fe content 'a' exceeds the upper limit, the nanocrystalline alloy soft magnetic powder cannot stably form an amorphous structure during manufacturing, resulting in excessively large crystallite diameters and increased coercivity.

[0054] When copper (Cu) is used to manufacture the nanocrystalline alloy soft magnetic powder described in this embodiment, it tends to separate from Fe. Therefore, due to the presence of Cu, compositional fluctuations occur, creating regions within the particles that are prone to partial crystallization. As a result, the precipitation of the Fe phase, which has a relatively easy-to-crystallize body-centered cubic lattice, is promoted, easily forming grains with the aforementioned crystallite diameter.

[0055] The Cu content b is 0.3 atomic% or more and 2.0 atomic% or less, preferably 0.5 atomic% or more and 1.5 atomic% or less, and more preferably 0.7 atomic% or more and 1.3 atomic% or less. It should be noted that if the Cu content b is below the lower limit, grain refinement is impaired, and grains with a microcrystal diameter within the aforementioned range cannot be formed. On the other hand, if the Cu content b exceeds the upper limit, the mechanical properties of the nanocrystalline alloy soft magnetic powder decrease, and it becomes brittle.

[0056] When Nb (niobium) is supplied from a state containing a large amount of amorphous structure to heat treatment, it, together with Cu, contributes to grain refinement. Therefore, it is easy to form grains with the microcrystal diameters described above.

[0057] The Nb content c is 2.0 atomic% or more and 4.0 atomic% or less, preferably 2.5 atomic% or more and 3.5 atomic% or less, and more preferably 2.7 atomic% or more and 3.3 atomic% or less. Furthermore, if the Nb content c is below the lower limit, grain refinement is impaired, and grains with crystallite diameters within the aforementioned range cannot be formed. On the other hand, if the Nb content c exceeds the upper limit, the mechanical properties of the nanocrystalline alloy soft magnetic powder decrease, and it becomes brittle. In addition, the magnetic permeability of the nanocrystalline alloy soft magnetic powder decreases.

[0058] When silicon (Si) is used to manufacture the nanocrystalline alloy soft magnetic powder according to the embodiments, it promotes amorphization. Therefore, once a homogeneous amorphous structure is formed during the manufacture of the nanocrystalline alloy soft magnetic powder according to the embodiments, it is easy to form grains with more uniform crystallite diameters by crystallization thereafter. The uniform crystallite diameter helps to average the crystalline magnetic anisotropy in each grain, thus reducing coercivity and increasing permeability, which contributes to the improvement of soft magnetism.

[0059] Boron (B) promotes amorphization when used to manufacture the nanocrystalline alloy soft magnetic powder according to the embodiments. Therefore, once a homogeneous amorphous structure is formed during the manufacture of the nanocrystalline alloy soft magnetic powder according to the embodiments, it is easy to form grains with more uniform crystallite diameters by crystallization. As a result, coercivity can be reduced and permeability increased, thereby improving soft magnetic properties. Furthermore, by using Si and B together, amorphization can be synergistically promoted based on the difference in their atomic radii.

[0060] Chromium (Cr) improves the oxidation resistance of nanocrystalline alloy soft magnetic powder. Therefore, during the pressing of the nanocrystalline alloy soft magnetic powder, the decrease in powder density due to oxides can be suppressed. Consequently, the influence of oxides on magnetic properties can be suppressed. Furthermore, by optimizing the Cr content, the crystallite diameter in the nanocrystalline alloy soft magnetic powder can be controlled to prevent it from becoming too small or too large. As a result, the increase in coercivity of the nanocrystalline alloy soft magnetic powder can be suppressed.

[0061] In addition, the total content of Si, B and Cr (Si+B+Cr) is set to 1, and the ratio of the total content of B and Cr (B+Cr) to the total content (Si+B+Cr) is set to x.

[0062] x satisfies 0.55≤x≤0.91, but preferably 0.60≤x≤0.90, and more preferably 0.65≤x≤0.80. This achieves a balance between the amounts of Si, B, and Cr. Consequently, it is possible to achieve a good balance between improving the oxidation resistance and magnetic permeability of the nanocrystalline alloy soft magnetic powder.

[0063] Furthermore, if x is below the lower limit, oxidation resistance decreases, and the crystallite diameter becomes too small, resulting in decreased magnetic permeability. On the other hand, if x exceeds the upper limit, the crystallite diameter becomes too large, leading to increased coercivity.

[0064] In addition, the ratio of Cr content to the total content (B+Cr) is set as y.

[0065] Y satisfies 0 ≤ y ≤ 0.185, but preferably satisfies 0.020 ≤ y ≤ 0.150, and more preferably satisfies 0.045 ≤ y ≤ 0.120. This achieves a balance between the amounts of B and Cr. Consequently, both the oxidation resistance and magnetic permeability of the nanocrystalline alloy soft magnetic powder can be effectively improved.

[0066] Alternatively, y can be lower than the lower limit, but depending on the overall composition, oxidation resistance may decrease. On the other hand, if y exceeds the upper limit, the crystallite diameter becomes too large and coercivity increases.

[0067] The Si content is preferably 1.5 atomic% or more and 14.0 atomic% or less, more preferably 3.0 atomic% or more and 10.0 atomic% or less, and even more preferably 4.0 atomic% or more and 8.0 atomic% or less. This yields a nanocrystalline alloy soft magnetic powder capable of producing pressed powder with lower coercivity and better DC superposition characteristics.

[0068] The content of B is preferably 5.0 atomic% or more and 17.0 atomic% or less, more preferably 7.0 atomic% or more and 16.0 atomic% or less, and even more preferably 9.0 atomic% or more and 14.0 atomic% or less. This yields a nanocrystalline alloy soft magnetic powder capable of producing pressed powder with lower coercivity and better DC superposition characteristics.

[0069] The Cr content is preferably 0 atomic% or more and 2.7 atomic% or less, more preferably 0.5 atomic% or more and 2.2 atomic% or less, and even more preferably 0.8 atomic% or more and 1.8 atomic% or less. This further improves the oxidation resistance of the nanocrystalline alloy soft magnetic powder and reduces the formation of oxides. As a result, the crystallite diameter of each particle can be appropriately controlled.

[0070] The nanocrystalline alloy soft magnetic powder involved in the implementation method, in addition to being composed of the above-mentioned Fe... a Cu b Nb c (Si 1-x (B 1-y Cr y ) x ) 100-a-b-c-d S d In addition to the indicated composition, impurities may also be included. All elements other than those mentioned above can be considered as impurities, but it is preferable that the total content of impurities is 0.50 atomic percent or less. If this range is within, even if impurities are introduced, it is difficult to hinder the aforementioned effects, and therefore their presence is permissible.

[0071] Furthermore, the content of each element contained in the impurities is preferably 0.05 atomic% or less. If it is within this range, the impurities are unlikely to hinder the above-mentioned effects, and therefore their presence is permissible.

[0072] Furthermore, the oxygen content in the impurities, particularly the nanocrystalline alloy soft magnetic powder, is preferably 800 ppm or more and 3000 ppm or less, more preferably 900 ppm or more and 2000 ppm or less, and even more preferably 1000 ppm or more and 1500 ppm or less. If the oxygen content is within the aforementioned range, the formation of oxides, which can cause a decrease in the density of the molded article, can be suppressed to a particularly small extent, and the interparticle insulation accompanying the oxides can be ensured to a certain extent.

[0073] Furthermore, if the oxygen content of the nanocrystalline alloy soft magnetic powder is lower than the lower limit, the insulation between particles decreases, making it easier to generate eddy currents between particles, which may increase the iron loss of the pressed magnetic core. On the other hand, if the oxygen content of the nanocrystalline alloy soft magnetic powder exceeds the upper limit, the density of the pressed powder decreases, and the magnetic properties of the pressed magnetic core may decrease.

[0074] The above describes the nanocrystalline alloy soft magnetic powder involved in the embodiments. The above composition and impurities were determined by the following analytical methods.

[0075] Examples of analytical methods include the atomic absorption spectrophotometry of iron and steel as specified in JIS G1257:2000, the ICP emission spectrophotometry of iron and steel as specified in JIS G1258:2007, the spark discharge emission spectrophotometry of iron and steel as specified in JIS G1253:2002, the fluorescence X-ray analysis of iron and steel as specified in JIS G1256:1997, and the gravimetric / titration / absorbance spectrophotometry as specified in JIS G1211 to G1237.

[0076] Specifically, examples include solid-state emission spectrometers manufactured by SPECTRO Corporation, and in particular spark discharge emission spectrometers (model: SPECTROLAB, type: LAMVB08A, and ICP device CIROS120 manufactured by Rigaku Corporation).

[0077] Furthermore, the oxygen flow combustion (high-frequency induction furnace combustion)-infrared absorption method specified in JIS G1211:2011 is used, especially in determining C (carbon) and S (sulfur). Specifically, the LECO CS-200 carbon / sulfur analyzer can be cited as an example.

[0078] Furthermore, especially in determining N (nitrogen) and O (oxygen), the quantitative methods for nitrogen determination in iron and steel as specified in JIS G1228:1997 and the general rules for quantitative methods for oxygen determination in metallic materials as specified in JIS Z2613:2006 are also used. Specifically, examples include the LECO TC-300 / EF-300 oxygen / nitrogen analyzer and the LECO ONH836 oxygen / nitrogen / hydrogen analyzer.

[0079] 1.2. Particle size

[0080] The particle size D10 of the nanocrystalline alloy soft magnetic powder involved in the embodiments is 7.0 μm or more and 15.0 μm or less, preferably 8.0 μm or more and 14.0 μm or less, and more preferably 9.0 μm or more and 13.0 μm or less.

[0081] If the particle size D10 of the nanocrystalline alloy soft magnetic powder is within the specified range, the particle size distribution can be optimized, thus obtaining a nanocrystalline alloy soft magnetic powder with high flowability and filling properties. This facilitates the improvement of the permeability and saturation flux density of the pressed magnetic core.

[0082] If the particle size D10 of the nanocrystalline alloy soft magnetic powder is lower than the lower limit, the nanocrystalline alloy soft magnetic powder becomes too fine, thus its filling capacity tends to decrease. Consequently, due to the reduced forming density of the pressed magnetic core, the permeability and saturation flux density of the pressed magnetic core may decrease depending on the composition and mechanical properties of the nanocrystalline alloy soft magnetic powder. On the other hand, if the average particle size of the nanocrystalline alloy soft magnetic powder exceeds the upper limit, fewer particles fill the gaps between the particles, and the forming density of the pressed magnetic core may also decrease.

[0083] The particle size D50 of the nanocrystalline alloy soft magnetic powder involved in the embodiments is 22.0 μm or more and 32.0 μm or less, preferably 23.0 μm or more and 31.0 μm or less, and more preferably 25.0 μm or more and 30.0 μm or less.

[0084] If the particle size D50 of the nanocrystalline alloy soft magnetic powder is within the specified range, the particle size distribution can be optimized, resulting in nanocrystalline alloy soft magnetic powder with high flowability and filling properties. This facilitates the improvement of the permeability and saturation flux density of the pressed magnetic core. Furthermore, suppressing eddy current losses generated within the particles allows for lower iron losses in the magnetic components.

[0085] If the particle size D50 of the nanocrystalline alloy soft magnetic powder is lower than the lower limit, the powder becomes too fine, thus reducing its filling capacity. Consequently, due to the reduced forming density of the pressed magnetic core, the permeability and saturation flux density of the core may decrease depending on the composition and mechanical properties of the nanocrystalline alloy soft magnetic powder. On the other hand, if the average particle size of the nanocrystalline alloy soft magnetic powder exceeds the upper limit, eddy current losses generated within the particles cannot be sufficiently suppressed, potentially increasing the iron loss of the magnetic element.

[0086] Furthermore, for the nanocrystalline alloy soft magnetic powder involved in the embodiments, in the cumulative particle size distribution under the volume reference obtained using a laser diffraction particle size distribution measuring device, the particle size at which the cumulative frequency from the small diameter side is 90% is set as D90.

[0087] The ratio of the particle size D10 to the particle size D90 of the nanocrystalline alloy soft magnetic powder involved in the embodiment is defined as the particle size ratio D10 / D90. The particle size ratio D10 / D90 is preferably 0.180 or more and 0.220 or less, more preferably 0.190 or more and 0.210 or less. If the particle size ratio D10 / D90 is within this range, the particle size distribution can be optimized, resulting in a nanocrystalline alloy soft magnetic powder with high flowability and filling properties. This facilitates the improvement of the permeability and saturation flux density of the pressed magnetic core.

[0088] If the particle size ratio D10 / D90 of the nanocrystalline alloy soft magnetic powder is lower than the lower limit, tiny particles are generated, which may reduce the flowability and filling properties of the nanocrystalline alloy soft magnetic powder. On the other hand, if the particle size ratio D10 / D90 of the nanocrystalline alloy soft magnetic powder exceeds the upper limit, fewer particles fill the gaps between the particles, and the forming density of the pressed magnetic core may decrease.

[0089] 1.3. Crystalline diameter

[0090] The nanocrystalline alloy soft magnetic powder involved in the embodiment has a crystallite diameter of 1.0 nm or more and 30.0 nm or less, as determined by X-ray diffraction. If the crystallite diameter is within this range, the crystallite diameter of the nanocrystalline alloy soft magnetic powder is optimized, thus the crystalline magnetic anisotropy in each crystallite is easily averaged, resulting in a nanocrystalline alloy soft magnetic powder that combines low coercivity and ease of manufacture. Furthermore, it is possible to achieve a nanocrystalline alloy soft magnetic powder with stable permeability over a wide frequency range. Therefore, since magnetic saturation is difficult to occur, a nanocrystalline alloy soft magnetic powder capable of realizing magnetic elements with good DC superposition characteristics and excellent operational stability is obtained.

[0091] In addition, the crystallite diameter in the nanocrystalline alloy soft magnetic powder is preferably 3.0 nm or more and 20.0 nm or less, more preferably 6.0 nm or more and 15.0 nm or less.

[0092] The determination of crystallite diameter based on X-ray diffraction was performed as follows: X-ray diffraction patterns were obtained for both the nanocrystalline alloy soft magnetic powder and a standard sample. After estimating the diffraction line width from Fe, the crystallite diameter was calculated using the Scherrer method. The X-ray diffraction pattern obtained from the standard sample was used to estimate the diffraction line width from the apparatus. The crystallite diameter calculated from the nanocrystalline alloy soft magnetic powder was corrected using the diffraction line width obtained from the standard sample.

[0093] Each particle constituting the nanocrystalline alloy soft magnetic powder according to the embodiment contains grains that satisfy the above-mentioned crystallite diameter, but may further contain amorphous structures. The coexistence of grains and amorphous structures further reduces the magnetostriction of the nanocrystalline alloy soft magnetic powder. As a result, a nanocrystalline alloy soft magnetic powder with low permeability is obtained.

[0094] Furthermore, if the crystallite diameter of the nanocrystalline alloy soft magnetic powder is lower than the lower limit, the manufacturing difficulty of the nanocrystalline alloy soft magnetic powder may increase. On the other hand, if the crystallite diameter of the nanocrystalline alloy soft magnetic powder exceeds the upper limit, the coercivity decreases, and the magnetic properties may decrease.

[0095] 1.4. Mass ratio

[0096] When the nanocrystalline alloy soft magnetic powder involved in the embodiments is graded according to the following steps, the mass ratio of the graded products preferably meets the predetermined conditions.

[0097] First, the nanocrystalline alloy soft magnetic powder was classified using a first sieve with a pore size of 53 μm. The fraction that passed through the first sieve was designated as -53 particles. Next, the -53 particles were classified using a second sieve with a pore size of 25 μm. The fraction that passed through the second sieve was designated as -25 particles.

[0098] In the nanocrystalline alloy soft magnetic powder, the mass ratio of -25 particles to -53 particles is preferably 40% or more and 65% or less, more preferably 45% or more and 63% or less, and even more preferably 50% or more and 61% or less. This optimizes the mass ratio of particles on both sides of the 25 μm particle size, further optimizing the particle size distribution. As a result, a nanocrystalline alloy soft magnetic powder with exceptionally high flowability and filling properties is obtained.

[0099] 1.5. Average roundness

[0100] The average sphericity of the nanocrystalline alloy soft magnetic powder involved in the embodiment is preferably 0.85 or more and less than 1.00, more preferably 0.87 or more and less than 0.97, and even more preferably 0.89 or more and less than 0.95. This achieves particle sphericity, thus enabling a near-dense filling state and improving manufacturing ease.

[0101] It should be noted that if the average sphericity is below the lower limit, the particle flowability and filling properties of the nanocrystalline alloy soft magnetic powder may decrease. On the other hand, if the average sphericity exceeds the upper limit, the manufacturing difficulty increases, and the manufacturing efficiency of the nanocrystalline alloy soft magnetic powder may decrease.

[0102] The average sphericity of the nanocrystalline alloy soft magnetic powder was determined as follows.

[0103] First, images of the nanocrystalline alloy soft magnetic powder (secondary electron images) were captured using a scanning electron microscope (SEM). Next, the obtained images were imported into image processing software. For example, image processing software such as "Mac-View," an image resolution particle size distribution measurement software manufactured by Mounttech Co., Ltd., was used. It should be noted that the magnification was adjusted so that 50 to 100 particles were reflected in a single image. Then, multiple images were acquired to obtain a total of more than 300 particle images.

[0104] Next, using software, the roundness of more than 300 particle images was calculated, and the average value was obtained. The obtained average value is the average roundness of the nanocrystalline alloy soft magnetic powder. In addition, when the roundness is set as e, the area of ​​the particle image is set as S, and the circumference of the particle image is set as L, the roundness e is calculated by the following formula.

[0105]

[0106] 1.6. Tapped density

[0107] The tap density of the nanocrystalline alloy soft magnetic powder involved in the embodiment is preferably 4.90 g / cm³. 3 Above 5.20 g / cm³ 3 Below, more preferably 4.90 g / cm³ 3 Above and 5.10 g / cm³ 3 Below. Within the stated tap density range, a nanocrystalline alloy soft magnetic powder with exceptionally high flowability and filling properties is obtained.

[0108] Furthermore, if the tap density is lower than the lower limit, the filling properties of the nanocrystalline alloy soft magnetic powder may decrease when it is pressed into a powder core. On the other hand, if the tap density exceeds the upper limit, the manufacturing difficulty of the nanocrystalline alloy soft magnetic powder increases, and the manufacturing yield may decrease.

[0109] The tap density of the nanocrystalline alloy soft magnetic powder was determined according to the metal powder tap density determination method specified in JIS Z2512:2012.

[0110] 1.7. Magnetic permeability

[0111] When the permeability of the nanocrystalline alloy soft magnetic powder involved in the embodiment is measured at a frequency of 1 MHz after the test subject is prepared, the measured permeability is preferably 22 or more, more preferably 24 or more and 40 or less.

[0112] Based on this composition, a nanocrystalline alloy soft magnetic powder capable of manufacturing magnetic components with high permeability is obtained.

[0113] In addition, the methods for preparing the test specimen and measuring the magnetic permeability are described below.

[0114] First, epoxy resin, in an amount equivalent to 2.0% by mass of the nanocrystalline alloy soft magnetic powder, was mixed with the nanocrystalline alloy soft magnetic powder. The resulting mixture was then subjected to a pressure of 294.2 MPa (3 t / cm). 2 The sample is pressed and shaped under pressure. This yields a ring-shaped specimen with an outer diameter of 14 mm, an inner diameter of 8 mm, a thickness of 3 mm, and a relative density of 66%. Relative density is the relative value obtained by dividing the mass of the specimen by its volume and then dividing that density by the true density of the nanocrystalline alloy soft magnetic powder. Next, a 0.6 mm diameter wire is wound seven turns around the resulting specimen. Then, the permeability of the specimen is measured at a frequency of 1 MHz. For example, an impedance analyzer such as the Agilent Technologies 4194A is used for the permeability measurement.

[0115] 1.8 Iron Loss

[0116] After the nanocrystalline alloy soft magnetic powder involved in the embodiment is used to prepare the test object described later, the iron loss measured when measuring the iron loss is preferably 1500 kW / m. 3 The following is more preferably 1000kW / m 3 The following is an example. This enables the production of nanocrystalline alloy soft magnetic powders that can be applied to power-saving electronic devices and the like.

[0117] In addition, the methods for preparing the test specimen and measuring iron loss are described below.

[0118] First, epoxy resin, in an amount equivalent to 2.0% by mass of the nanocrystalline alloy soft magnetic powder, was mixed with the nanocrystalline alloy soft magnetic powder. The resulting mixture was then subjected to a pressure of 49.0 MPa (0.5 t / cm). 2 The powder is pressed into shape under pressure. This yields a ring-shaped powder body with an outer diameter of 14 mm, an inner diameter of 8 mm, and a thickness of 3 mm. Next, a 0.16 mm diameter wire is wound onto the powder body with 18 turns on the primary side and 18 turns on the secondary side to obtain the test object. The wire is made of Cu. Then, the iron loss of the test object is measured. The iron loss measurement is performed using a BH analyzer SY-8218 manufactured by Iwasaki Telecommunications Equipment Co., Ltd., with the measurement frequency set to 1 MHz and the maximum magnetic flux density set to 20 mT.

[0119] Furthermore, the ratio of particle size D10 to iron loss Pi, D10 / Pi, is preferably 0.0011 [(μm·kW) / m]. 3 Above and 0.0020 [(μm·kW) / m 3 Below that, 0.0012 [(μm·kW) / m] is more preferred. 3 Above and 0.0019 [(μm·kW) / m 3 Below that, 0.0013 [(μm·kW) / m] is further preferred. 3 Above and 0.0018 [(μm·kW) / m 3 ]the following.

[0120] Based on this configuration, the ratio of particle size D10 to iron loss Pi, D10 / Pi, is optimized, thus obtaining a nanocrystalline alloy soft magnetic powder with high forming density for pressed magnetic cores and capable of achieving low iron loss in magnetic components.

[0121] 2. Method for manufacturing nanocrystalline alloy soft magnetic powder

[0122] Next, an example of a method for manufacturing the nanocrystalline alloy soft magnetic powder involved in the above embodiments will be described.

[0123] Nanocrystalline alloy soft magnetic powders are manufactured, for example, by performing a crystallization process (heat treatment) after the production of metal powders.

[0124] Methods for manufacturing metal powders include various atomization methods such as water atomization, rotating water atomization, and gas atomization, as well as pulverization. Among these, atomization is preferred.

[0125] The atomization method is as follows: by colliding molten metal with a high-speed jet of liquid or gas, the molten metal is pulverized and cooled at the same time, thereby producing metal powder.

[0126] The water atomization method is as follows: using water or other liquids as coolants, spraying them into an inverted cone shape that converges to a single point, and causing molten metal to flow down and collide with this converged point, thereby producing metal powder from the molten metal.

[0127] The rotating water jet atomization method is as follows: coolant is supplied along the inner circumferential surface of the cooling cylinder, causing it to swirl along the inner circumferential surface; on the other hand, a jet of liquid or gas is blown onto the molten metal, collecting the scattered molten metal into the coolant, thereby producing metal powder.

[0128] Gas atomization is a method that uses gas as a cooling medium, sprays it into an inverted cone shape that is concentrated at a single point, and causes molten metal to flow down and collide with this concentrated point, thereby producing metal powder from the molten metal.

[0129] The manufactured metal powder may also be classified as needed. Examples of classification methods include dry classification such as sieving, inertial classification, centrifugal classification, and air classification, and wet classification such as sedimentation classification.

[0130] The resulting metal powder consists of particles with an amorphous structure. By subjecting such metal powder to the crystallization treatment (heat treatment) described later, nanocrystalline alloy soft magnetic powder is obtained.

[0131] The heat treatment temperature is preferably 420°C or higher and 620°C or lower, more preferably 470°C or higher and 610°C or lower, and even more preferably 500°C or higher and 600°C or lower. If the heat treatment temperature is within the specified range, stress and strain can be adequately relieved while properly crystallizing the amorphous structure.

[0132] In heat treatment, the time for maintaining the above temperature (the heat treatment time) is preferably 5 minutes or more and 60 minutes or less, more preferably 7 minutes or more and 45 minutes or less, and even more preferably 10 minutes or more and 30 minutes or less. If the heat treatment time is within the above range, the amorphous structure can be properly crystallized, and stress and strain can be adequately relieved.

[0133] Heat treatment is performed, for example, using a heat treatment furnace. The pressure inside the heat treatment furnace can be atmospheric pressure, negative pressure, or positive pressure. Positive pressure is preferred. By performing heat treatment under positive pressure inside the heat treatment furnace, the thermal conductivity around the metal powder can be increased. This allows for uniform heating of the metal powder throughout the furnace, and as a whole, it suppresses deviations in the crystallite diameter of the manufactured nanocrystalline alloy soft magnetic powder, further reducing coercivity.

[0134] The pressure inside the heat treatment furnace is preferably a positive pressure of 5 Pa or more and 1000 Pa or less, more preferably a positive pressure of 10 Pa or more and 700 Pa or less, and even more preferably a positive pressure of 30 Pa or more and 500 Pa or less.

[0135] Furthermore, if the pressure inside the heat treatment furnace is lower than the lower limit, the temperature of each particle during heat treatment may deviate, potentially resulting in insufficient or excessive heat treatment in some areas. On the other hand, if the pressure inside the heat treatment furnace exceeds the upper limit, the aforementioned effects cannot be predicted, and the energy efficiency of the heat treatment may decrease.

[0136] Additionally, a positive pressure of 10 Pa refers to a pressure 10 Pa higher than atmospheric pressure; for example, when atmospheric pressure is 101.3 kPa, it means 101.31 kPa.

[0137] The atmosphere inside the heat treatment furnace is not particularly limited and can be an acidic atmosphere, a reducing atmosphere, etc., but is preferably an inert atmosphere, more preferably an inert atmosphere with an oxygen volume concentration of 1500 ppm or less, further preferably an inert atmosphere with an oxygen volume concentration of 200 ppm or more and 1000 ppm or less, and particularly preferably an inert atmosphere with an oxygen volume concentration of 300 ppm or more and 700 ppm or less. If the oxygen volume concentration of the inert atmosphere is within the above range, the oxidation of the metal powder can be suppressed more reliably. Furthermore, if an oxide film forms, stress and strain may become difficult to alleviate. In view of this, if the oxygen volume concentration is within the above range, the coercivity of the nanocrystalline alloy soft magnetic powder can be effectively reduced by heat treatment.

[0138] In addition, inert gases that constitute an inert atmosphere can be exemplified by nitrogen and argon.

[0139] Furthermore, depending on the requirements, an insulating film can also be formed on the surface of each particle of the obtained nanocrystalline alloy soft magnetic powder. Examples of materials constituting this insulating film include inorganic materials such as phosphates (e.g., magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, cadmium phosphate), silicates (e.g., sodium silicate), ceramic materials such as silicon dioxide, alumina, magnesium oxide, zirconium oxide, titanium dioxide, and glass materials such as borosilicate glass and silica glass.

[0140] 3. Powder-pressed magnetic cores and magnetic components

[0141] Next, the pressed powder core and magnetic elements involved in the embodiments will be described.

[0142] The magnetic components described in the embodiments can be applied to various magnetic components with magnetic cores, such as chokes, inductors, noise filters, reactors, transformers, motors, actuators, solenoid valves, and generators. Furthermore, the powder-pressed magnetic cores described in the embodiments can be applied to the magnetic cores of these magnetic components.

[0143] The following description uses two types of coil components as examples of magnetic elements.

[0144] 3.1. Ring type

[0145] First, the ring-shaped coil component, which is the magnetic element involved in the embodiment, will be described.

[0146] Figure 1 This is a schematic top view of a ring-shaped coil component 10. Figure 1 The coil component 10 shown has an annular pressed powder core 11 and a wire 12 wound around the pressed powder core 11.

[0147] The pressed powder core 11 is obtained by mixing the nanocrystalline alloy soft magnetic powder according to the embodiment with a binder and molding the resulting mixture. The pressed powder core 11 is a pressed powder body containing the nanocrystalline alloy soft magnetic powder according to the embodiment. Therefore, a coil component 10 with high magnetic permeability and low iron loss is obtained. Moreover, when the above-mentioned coil component 10 is mounted in electronic devices, it is possible to achieve high performance, miniaturization, and power saving in electronic devices, etc.

[0148] The constituent materials of the adhesive used in the fabrication of the pressed powder magnetic core 11 include, for example, organic materials such as silicone resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, and polyphenylene sulfide resins, as well as inorganic materials such as phosphates such as magnesium phosphate, calcium phosphate, zinc phosphate, manganese phosphate, and cadmium phosphate, and silicates such as sodium silicate.

[0149] Materials with high conductivity can be used as the constituent material of the conductor 12, such as metallic materials containing Cu, Al, Ag, Au, Ni, etc. Furthermore, an insulating film may be provided on the surface of the conductor 12 as needed.

[0150] Furthermore, the shape of the pressed powder core 11 is not limited to Figure 1 The ring shape shown can be, for example, a shape with a missing part of the ring, or a shape where the long side is a straight line.

[0151] In addition, as needed, the pressed powder core 11 may also contain soft magnetic powder or non-magnetic powder other than the nanocrystalline alloy soft magnetic powder involved in the above embodiments.

[0152] 3.2. Closed magnetic circuit type

[0153] Next, a closed magnetic circuit type coil component, which is a magnetic element according to the embodiment, will be described.

[0154] Figure 2This is a schematic perspective view of a coil component 20 with a closed magnetic circuit.

[0155] The following description focuses on the closed magnetic circuit type coil component 20, but the description will focus on the differences from the toroidal type coil component 10, and the same items will be omitted.

[0156] Figure 2 The coil component 20 shown is formed by embedding a coil-shaped wire 22 inside a pressed powder core 21. The pressed powder core 21 is a pressed powder body containing the nanocrystalline alloy soft magnetic powder involved in the embodiment. Therefore, a coil component 20 with high magnetic permeability and low iron loss is obtained. Moreover, when the above-mentioned coil component 20 is mounted in electronic devices, it is possible to achieve high performance, miniaturization, and power saving in electronic devices.

[0157] In addition, as needed, the pressed powder core 21 may also contain soft magnetic powder or non-magnetic powder other than the nanocrystalline alloy soft magnetic powder involved in the above embodiments.

[0158] 4. Electronic devices

[0159] Next, based on Figures 3-5 An electronic device having the magnetic element described in the embodiments will be described.

[0160] Figure 3 This is a perspective view showing the structure of a mobile personal computer 1100, which is an electronic device according to an embodiment. Figure 3 The personal computer 1100 shown includes: a main body 1104 with a keyboard 1102; and a display unit 1106 with a display section 100. The display unit 1106 is supported by a hinge structure and is rotatable relative to the main body 1104. Such a personal computer 1100 may include, for example, magnetic components 1000 such as a choke for a switching power supply, an inductor, and a motor.

[0161] Figure 4 This is a top view showing the structure of a smartphone 1200, which is an electronic device according to an embodiment. Figure 4 The smartphone 1200 shown includes multiple operation buttons 1202, an earpiece 1204, and a microphone 1206. Furthermore, a display unit 100 is disposed between the operation buttons 1202 and the earpiece 1204. Such a smartphone 1200 may incorporate, for example, magnetic components 1000 such as inductors, noise filters, and motors.

[0162] Figure 5This is a perspective view showing the structure of a digital still camera 1300, which is an electronic device according to an embodiment. The digital still camera 1300 generates an image signal by photoelectric conversion of the optical image of the subject using an imaging element such as a CCD (Charge Coupled Device).

[0163] Figure 5 The digital still camera 1300 shown includes a display unit 100 located on the back of the housing 1302. The display unit 100 functions as a viewfinder that displays the subject as an electronic image. In addition, a light-receiving unit 1304, including an optical lens and a CCD, is provided on the front side of the housing 1302, i.e., the back side shown in the figure.

[0164] If the photographer confirms the image of the subject displayed on the display unit 100 and presses the shutter button 1306, the CCD image signal at that moment is transmitted / stored in the memory 1308. Such a digital still camera 1300 also incorporates, for example, magnetic components 1000 such as inductors and noise filters.

[0165] As an electronic device involved in the implementation method, besides Figure 3 Personal computer 1100 Figure 4 Smartphone 1200 Figure 5 Besides digital still cameras (1300), other examples include: mobile phones, tablets, watches, inkjet printers and other inkjet printing devices, laptops, televisions, video cameras, video recorders, car navigation systems, pagers, electronic notebooks, electronic dictionaries, calculators, video game consoles, word processors, workstations, videophones, anti-theft television monitors, electronic binoculars, POS terminals, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, electronic endoscopes and other medical equipment, fish detectors, various measuring instruments, instruments for vehicles, aircraft, and ships, mobile control devices such as automotive control devices, aircraft control devices, railway vehicle control devices, and ship control devices, flight simulators, etc.

[0166] Such an electronic device incorporates the magnetic element involved in the implementation method. Therefore, by utilizing the effects of the magnetic element, it is possible to achieve high performance, miniaturization, and power saving in the electronic device.

[0167] 5. Effects of the implementation method

[0168] As described above, the nanocrystalline alloy soft magnetic powder involved in the embodiments is composed of Fe, expressed in atomic ratio. a Cu b Nb c (Si 1-x(B 1-y Cr y ) x ) 100-a-b-c-d S d

[0169] [a, b, c, d, x, y satisfy]

[0170] 75.5≤a≤79.5,

[0171] 0.3≤b≤2.0,

[0172] 2.0≤c≤4.0,

[0173] 0.001≤d≤0.080,

[0174] 0.55≤x≤0.91,

[0175] 0≤y≤0.185]

[0176] The composition and impurities,

[0177] The nanocrystalline alloy soft magnetic powder contains crystallites with a diameter of 1.0 nm or more and 30.0 nm or less, as determined by X-ray diffraction.

[0178] In the cumulative particle size distribution under volume reference obtained using a laser diffraction particle size distribution measuring device, when the particle size at which the cumulative frequency reaches 10% from the small diameter side is defined as D10, and the particle size at which the cumulative frequency reaches 50% from the small diameter side is defined as D50,

[0179] The particle size D10 is greater than 7.0 μm and less than 15.0 μm.

[0180] The particle size D50 is above 22.0 μm and below 32.0 μm.

[0181] Based on this composition, the particle shape and particle size distribution were optimized to obtain a nanocrystalline alloy soft magnetic powder exhibiting good filling properties and magnetic properties.

[0182] In the nanocrystalline alloy soft magnetic powder involved in the above embodiment, it is preferable that when the -53 particles are classified using a first sieve with a pore size of 53 μm and the classified particles that pass through the first sieve are used as -53 particles, and the -53 particles are classified using a second sieve with a pore size of 25 μm and the classified particles that pass through the second sieve are used as -25 particles, the mass ratio of -25 particles to -53 particles is 40% or more and 65% or less.

[0183] Based on this composition, the mass ratio of particles on both sides of the 25μm particle size can be optimized, thus obtaining a nanocrystalline alloy soft magnetic powder with particularly high fluidity and filling properties.

[0184] In the nanocrystalline alloy soft magnetic powder involved in the above embodiment, it is preferable that, in the cumulative particle size distribution, when the particle size at which the cumulative frequency from the small diameter side is 90% is set as D90, and the ratio of particle size D10 to particle size D90 is set as particle size ratio D10 / D90, the particle size ratio D10 / D90 is 0.180 or more and 0.220 or less.

[0185] This composition allows for the optimization of particle size distribution, resulting in a nanocrystalline alloy soft magnetic powder with high flowability and filling capacity.

[0186] In the nanocrystalline alloy soft magnetic powder involved in the above embodiments, it is preferred that the tap density is 4.90 g / cm³. 3 Above 5.20 g / cm³ 3 ]the following.

[0187] Based on this composition, a nanocrystalline alloy soft magnetic powder with particularly high fluidity and filling properties is obtained.

[0188] Preferably, the nanocrystalline alloy soft magnetic powder involved in the above embodiment is mixed with epoxy resin at a mass ratio of 2.0%, and the resulting mixture is subjected to a pressure of 294.2 MPa (3 t / cm). 2 After being pressed and shaped under pressure to form a ring-shaped body with an outer diameter of 14 mm, an inner diameter of 8 mm, and a thickness of 3 mm, a 0.6 mm diameter wire is wound 7 turns around the ring-shaped body to form the test object. For the test object, the iron loss Pi is measured at a maximum magnetic flux density of 50 mT and a measurement frequency of 900 kHz. The ratio of the particle size D10 to the iron loss Pi, D10 / Pi, is 0.0011 [(μm·kW) / m]. 3 Above and 0.0020 [(μm·kW) / m 3 ]the following.

[0189] Based on this composition, a nanocrystalline alloy soft magnetic powder with high forming density and low iron loss is obtained for magnetic components with pressed powder cores.

[0190] In the nanocrystalline alloy soft magnetic powder involved in the above embodiments, it is preferred that the oxygen content is 800 ppm or more and 3000 ppm or less by mass.

[0191] With this configuration, the formation of oxides that could cause a decrease in the density of the molded body is suppressed to a very low extent, and the insulation between the particles accompanying the oxides can be ensured to some extent.

[0192] In the nanocrystalline alloy soft magnetic powder involved in the above embodiments, it is preferred that the average sphericity is 0.85 or more and less than 1.00.

[0193] Based on this composition, the particles of the nanocrystalline alloy soft magnetic powder are spherical, thus enabling the filling state to approach the densest filling and improving manufacturing ease.

[0194] The pressed powder magnetic core involved in the embodiments includes the nanocrystalline alloy soft magnetic powder involved in the embodiments.

[0195] Based on this configuration, a powder core is obtained that enables magnetic elements to achieve high permeability and low iron loss.

[0196] The magnetic element involved in the embodiment includes the pressed powder magnetic core involved in the embodiment.

[0197] Based on this configuration, magnetic components with high permeability and low iron loss are obtained.

[0198] The electronic device described in the embodiments includes the magnetic elements described in the embodiments.

[0199] Based on this configuration, high-performance, miniaturized, and power-saving electronic devices were obtained.

[0200] The above describes the nanocrystalline alloy soft magnetic powder, pressed magnetic core, magnetic element, and electronic device of the present invention based on preferred embodiments, but the present invention is not limited thereto.

[0201] For example, in the described embodiment, pressed powder cores and other pressed powder bodies are cited as examples of applications of the nanocrystalline alloy soft magnetic powder of the present invention. However, the applications are not limited to these examples; for instance, they can also be magnetic fluids, magnetic heads, and other magnetic devices. Furthermore, the shape of the pressed powder core and magnetic element is not limited to the shape shown in the figure and can be any shape.

[0202] Example

[0203] Next, specific embodiments of the present invention will be described.

[0204] 6. Preparation of Nanocrystalline Alloy Soft Magnetic Powder

[0205] Figure 6 Table 1 shows the composition of the nanocrystalline alloy soft magnetic powders of samples No.1 to 15. Figure 7 Table 2 shows the composition of the nanocrystalline alloy soft magnetic powders of samples No. 16-30. Figure 8 Table 3 shows the evaluation results of the nanocrystalline alloy soft magnetic powders of samples No.1 to No.15. Figure 9 Table 4 shows the evaluation results of the nanocrystalline alloy soft magnetic powders of samples No. 16 to 30.

[0206] 6.1. Sample No. 1

[0207] First, the raw materials are melted in a high-frequency induction furnace and then pulverized using a rotating water jet atomization method to obtain metal powder. The obtained metal powder is then classified using a sieve with a pore size of 53 μm.

[0208] Next, the obtained metal powder was subjected to heat treatment in a nitrogen atmosphere. The heat treatment conditions were: heat treatment temperature 570℃, heat treatment time 10 minutes, positive pressure 100 Pa, and oxygen volume concentration in the furnace 550 ppm.

[0209] As mentioned above, nanocrystalline alloy soft magnetic powder of sample No. 1 was obtained. The composition of the obtained nanocrystalline alloy soft magnetic powder and the microstructure of the metal powder before heat treatment are shown in Table 1. Figure 6 ).

[0210] 6.2. Samples No. 2 to 30

[0211] In addition to Table 1 ( Figure 6 ) or Table 2 ( Figure 7 Except for changing the manufacturing conditions of the nanocrystalline alloy soft magnetic powder, the nanocrystalline alloy soft magnetic powder was obtained in the same way as sample No.1.

[0212] Additionally, in Table 1 ( Figure 6 Table 4 Figure 9 In the present invention, the nanocrystalline alloy soft magnetic powder of each sample No. that is equivalent to the present invention is used as "Example", and the nanocrystalline alloy soft magnetic powder that is not equivalent to the present invention is used as "Comparative Example".

[0213] 7. Acquisition of the project constituting the nanocrystalline alloy soft magnetic powder

[0214] 7.1. Crystallite diameter of nanocrystalline alloy soft magnetic powder

[0215] For the nanocrystalline alloy soft magnetic powders of each embodiment and each comparative example, the crystallite diameter was determined by X-ray diffraction. The measurement results are shown in Table 3. Figure 8 ) and Table 4 ( Figure 9 ).

[0216] 7.2. Particle size of nanocrystalline alloy soft magnetic powder

[0217] The particle size D10, D50, and D90 of the nanocrystalline alloy soft magnetic powders from each embodiment and comparative example were measured. Furthermore, the particle size ratio D10 / D90 was calculated. The measurement and calculation results are shown in Tables 3 and 4.

[0218] 7.3. Oxygen content of nanocrystalline alloy soft magnetic powder

[0219] The oxygen content of the nanocrystalline alloy soft magnetic powders of each embodiment and comparative example was determined. An Oxygen / Nitrogen / Hydrogen Analyzer ONH836 from LECO was used for the oxygen content determination. The results are shown in Tables 3 and 4.

[0220] 7.4. Average sphericity of nanocrystalline alloy soft magnetic powder

[0221] The average sphericity of the nanocrystalline alloy soft magnetic powders for each embodiment and comparative example was calculated. The calculation results are shown in Tables 3 and 4.

[0222] 7.5. Mass ratio of nanocrystalline alloy soft magnetic powder

[0223] The mass ratio of -25 particles to -53 particles was calculated for the nanocrystalline alloy soft magnetic powders of each embodiment and comparative example. The calculation results are shown in Tables 3 and 4.

[0224] 8. Evaluation results of nanocrystalline alloy soft magnetic powder

[0225] 8.1. Tap density of nanocrystalline alloy soft magnetic powder

[0226] The tap density of the nanocrystalline alloy soft magnetic powders for each embodiment and comparative example was measured. The results are shown in Tables 3 and 4.

[0227] 8.2. Magnetic permeability of nanocrystalline alloy soft magnetic powder

[0228] The permeability of the nanocrystalline alloy soft magnetic powders for each embodiment and comparative example was measured. The obtained permeability was then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 3 and 4.

[0229] A: Permeability is 24 or higher

[0230] B: Permeability greater than 22 and less than 24

[0231] C: Permeability less than 22

[0232] 8.3. Iron loss of nanocrystalline alloy soft magnetic powder

[0233] The iron loss Pi was measured for the nanocrystalline alloy soft magnetic powders of each embodiment and comparative example. The results are shown in Tables 3 and 4.

[0234] In addition, the ratio of particle size D10 to iron loss Pi, D10 / Pi, was calculated. The calculation results are shown in Tables 3 and 4.

[0235] As shown in Tables 3 and 4, high tap density and high magnetic permeability were confirmed in the nanocrystalline alloy soft magnetic powders of each embodiment. These evaluation results can be attributed to the optimization of particle shape and size distribution of the nanocrystalline alloy soft magnetic powders in each embodiment, resulting in good flowability and filling properties.

[0236] Furthermore, in specimens prepared using the nanocrystalline alloy soft magnetic powders of each embodiment, a reduction in iron loss Pi was confirmed. This evaluation result can be attributed to the achievement of low coercivity and suppression of inter-particle and intra-particle eddy currents in the nanocrystalline alloy soft magnetic powders of each embodiment.

Claims

1. A nanocrystalline alloy soft magnetic powder, characterized in that, The nanocrystalline alloy soft magnetic powder is composed of Fe, expressed in atomic ratios. a Cu b Nb c (Si 1-x (B 1-y Cr y ) x ) 100-a-b-c-d S d The composition and impurities, a, b, c, d, x, and y satisfy: 75.5 ≤ a ≤ 79.5, 0.3 ≤ b ≤ 2.0, 2.0 ≤ c ≤ 4.0, 0.001 ≤ d ≤ 0.080, 0.55 ≤ x ≤ 0.91, and 0 ≤ y ≤ 0.

185. The nanocrystalline alloy soft magnetic powder contains crystallites with a diameter of 1.0 nm or more and 30.0 nm or less, as determined by X-ray diffraction. In the cumulative particle size distribution under volume reference obtained using a laser diffraction particle size distribution measuring device, when the particle size at which the cumulative frequency reaches 10% from the small diameter side is defined as D10, and the particle size at which the cumulative frequency reaches 50% from the small diameter side is defined as D50, The particle size D10 is greater than 7.0 μm and less than 15.0 μm. The particle size D50 is above 22.0 μm and below 32.0 μm.

2. The nanocrystalline alloy soft magnetic powder according to claim 1, wherein, When the -53 particles are classified using a first sieve with a pore size of 53 μm and the fraction passing through the first sieve is taken as -53 particles, and the -53 particles are classified using a second sieve with a pore size of 25 μm and the fraction passing through the second sieve is taken as -25 particles, the mass ratio of the -25 particles to the -53 particles is 40% or more and 65% or less.

3. The nanocrystalline alloy soft magnetic powder according to claim 1 or 2, wherein, In the cumulative particle size distribution, when the particle size at which the cumulative frequency reaches 90% from the smallest diameter side is defined as D90, and the ratio of the particle size D10 to the particle size D90 is defined as the particle size ratio D10 / D90, The particle size ratio D10 / D90 is greater than 0.180 and less than 0.

220.

4. The nanocrystalline alloy soft magnetic powder according to claim 1 or 2, wherein, The tap density is 4.90 g / cm³. 3 Above and 5.20 g / cm 3 the following.

5. The nanocrystalline alloy soft magnetic powder according to claim 1 or 2, wherein, The nanocrystalline alloy soft magnetic powder is mixed with epoxy resin at a mass ratio of 2.0%, and the resulting mixture is subjected to a pressure of 294.2 MPa, or 3 t / cm. 2 Under pressure, the material is pressed into shape. After forming a ring-shaped body with an outer diameter of 14 mm, an inner diameter of 8 mm, and a thickness of 3 mm, a 0.6 mm diameter wire is wound around the formed body 7 times to create the test object. For the test object, the iron loss Pi is measured at a maximum magnetic flux density of 50 mT and a measurement frequency of 900 kHz. The ratio of the particle size D10 to the iron loss Pi, D10 / Pi, is 0.0011 (μm·kW) / m. 3 Above and 0.0020 (μm·kW) / m 3 the following.

6. The nanocrystalline alloy soft magnetic powder according to claim 1 or 2, wherein, The oxygen content, by mass, is above 800 ppm and below 3000 ppm.

7. The nanocrystalline alloy soft magnetic powder according to claim 1 or 2, wherein, The average roundness is above 0.85 and less than 1.

00.

8. A pressed powder magnetic core, characterized in that, The pressed powder core comprises the nanocrystalline alloy soft magnetic powder as described in claim 1 or 2.

9. A magnetic element, characterized in that, The magnetic element comprises the pressed powder magnetic core as described in claim 8.

10. An electronic device, characterized in that, The electronic device includes the magnetic element as described in claim 9.

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