Soft magnetic powder

Abstract

To provide a soft magnetic powder allowed to be nano-crystallized with stability.SOLUTION: A soft magnetic powder has a glass transition temperature Tg, a first crystallization-onset temperature Tx1 and a second crystallization-onset temperature Tx2. The first crystallization-onset temperature Tx1 is 400°C or higher and 475°C or lower. The first crystallization-onset temperature Tx1 and the glass transition temperature Tg has a difference, ΔTx=Tx1-Tg, of 50°C or lower. The second crystallization-onset temperature Tx2 and the first crystallization-onset temperature Tx1 has a difference, ΔT=Tx2-Tx1, of 65°C or higher and 135°C or lower.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to soft magnetic powder, and more particularly to soft magnetic powder used in magnetic components. [Background technology]

[0002] Magnetic cores constituting magnetic components require excellent magnetic properties (high saturation magnetic flux density and low core loss). Nanocrystalline materials are known as magnetic materials that can achieve such magnetic properties. Nanocrystalline materials can be obtained by heat-treating soft magnetic powder in a nanocrystallization process. Soft magnetic powders used in the production of nanocrystalline materials are disclosed, for example, in Patent Document 1 and Patent Document 2. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 5632608 [Patent Document 2] Patent No. 6741108 [Overview of the project] [Problems that the invention aims to solve]

[0004] The heat treatment in the nanocrystallization process causes self-heating of the soft magnetic powder. Therefore, it is difficult to control the temperature of the soft magnetic powder during the nanocrystallization process. As a result, the nanocrystalline material obtained by the nanocrystallization process has the problem of having easily variable properties. In other words, there is a problem in that it is difficult to stably perform nanocrystallization of soft magnetic powder.

[0005] Therefore, the present invention aims to provide a soft magnetic powder that can be stably subjected to nanocrystallization. [Means for solving the problem]

[0006] The present invention provides a first soft magnetic powder, which is a soft magnetic powder, The soft magnetic powder has a glass transition temperature Tg, a first crystallization start temperature Tx1, and a second crystallization start temperature Tx2, and The glass transition temperature Tg is between 360°C and 428°C. the first crystallization start temperature Tx1 is 400°C or higher and 475°C or lower can be, The aforementioned The difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 65°C or higher and 135°C or lower And, The aforementioned soft magnetic powder has the compositional formula Fe , either , , , y , We provide soft magnetic powder. ,

[0007] , Cu , , b , , , The difference ΔTx = Tx1 - Tg between the first crystallization start temperature Tx1 and the glass transition temperature Tg is 50°C or less. , 75.4at% ≤ a ≤ 80.4at% , z , , Cr , 0.3at% ≤ x ≤ 0.9at% , c , The core loss is 1250 kW / m³. , , Si , 4.5at% ≤ c ≤ 12at% , , The aforementioned soft magnetic powder has the compositional formula Fe , , , , , 3 , Furthermore, the present invention provides a third soft magnetic powder, which is the first or second soft magnetic powder. , 4 , Nb , , d , The following is , We provide soft magnetic powder. , P , , The aforementioned , , It is represented as, , 0at% ≤ y + z ≤ 5at% , x , , From the 3rd , B , 4at% ≤ d ≤ 12at% , a , Furthermore, the present invention provides a second soft magnetic powder, which is a first soft magnetic powder. , , 0at%≦b≦9at% , And, , Si b P c B d Cu x Cr y Nb z It is represented as, 75.4at% ≤ a ≤ 80.4at% 0at%≦b≦9at% 4.5at% ≤ c ≤ 12at% 4at% ≤ d ≤ 12at% 0.3at% ≤ x ≤ 0.9at% 0at% ≤ y + z ≤ 5at% is provided. A soft magnetic powder is provided. Furthermore, the present invention provides a second soft magnetic powder, which is a first soft magnetic powder. The core loss is 1250 kW / m³. 3 The following is We provide soft magnetic powder. Furthermore, the present invention provides a third soft magnetic powder, which is the first or second soft magnetic powder. The difference ΔTx = Tx1 - Tg between the first crystallization start temperature Tx1 and the glass transition temperature Tg is 50°C or less. We provide soft magnetic powder.

[0007] In addition, the present invention provides, as the soft magnetic powder of the 4 first From the 3rd soft magnetic powder either where the first crystallization start temperature Tx1 is 420°C or higher and 460°C or lower We provide soft magnetic powder.

[0008] Furthermore, the present invention relates to the first 5 As a soft magnetic powder, the first From the fourth soft magnetic powder either And, The difference ΔTx = Tx1 - Tg between the first crystallization start temperature Tx1 and the glass transition temperature Tg is between 20°C and 50°C. We provide soft magnetic powder.

[0009] Furthermore, the present invention relates to the first 6 As soft magnetic powders, the first to the 5 Any of the soft magnetic powders, The difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 75°C or greater. We provide soft magnetic powder.

[0011] Furthermore, the present invention relates to the first 7 As a soft magnetic powder, 1 to 6 soft magnetic powder either And, 77at% ≤ a ≤ 79at% That is We provide soft magnetic powder.

[0012] Furthermore, the present invention relates to the first 8 As a soft magnetic powder, 7 A soft magnetic powder, A portion of the aforementioned Fe, comprising 3 at% or less of the total composition, is substituted with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi, and rare earth elements. We provide soft magnetic powder.

[0013] Furthermore, the present invention relates to the first 9 As soft magnetic powders, the first to the 8 Any of the soft magnetic powders, The average particle size is between 1 μm and 20 μm. We provide soft magnetic powder.

[0014] Furthermore, the present invention relates to the first 10 As soft magnetic powders, the first to the 9 Any of the soft magnetic powders, The degree of crystallinity after rapid cooling is 10% or less. We provide soft magnetic powder. [Effects of the Invention]

[0015] The soft magnetic powder of the present invention has a glass transition temperature Tg, so endothermic heat is generated during the nanocrystallization process due to the glass transition, suppressing self-heating during nanocrystallization. In addition, the soft magnetic powder of the present invention has a first crystallization start temperature Tx1 and a second crystallization start temperature Tx2 that satisfy predetermined temperature conditions. Therefore, the soft magnetic powder of the present invention can undergo stable nanocrystallization and sufficiently precipitate fine nanocrystals. [Brief explanation of the drawing]

[0016] [Figure 1] This graph shows the results of differential scanning calorimetry (DSC) of soft magnetic powder according to an embodiment of the present invention. [Modes for carrying out the invention]

[0017] The soft magnetic powder according to one embodiment of the present invention is an Fe-based soft magnetic alloy powder in which Fe is the main element and the amorphous phase is the main phase. Its composition will be described later. The soft magnetic powder of this embodiment is used, for example, in the fabrication of magnetic cores for magnetic components. In the process of fabricating the magnetic core, the soft magnetic powder is heat-treated to undergo nanocrystallization.

[0018] The soft magnetic powder according to this embodiment can be produced by various manufacturing methods. For example, the soft magnetic powder may be produced by atomization methods such as water atomization or gas atomization. In the powder production process by atomization, first, raw materials are prepared. Next, the raw materials are weighed to a predetermined composition (listed in Table 1-8) and melted to produce a molten alloy. Next, the molten alloy is discharged from a nozzle and separated into molten alloy droplets using high-pressure gas or water, thereby producing fine soft magnetic powder.

[0019] In the powder preparation process described above, the gas used for fragmentation may be an inert gas such as argon or nitrogen. Furthermore, to improve the cooling rate, the alloy droplets may be rapidly cooled by contacting them with a cooling liquid or solid immediately after fragmentation, or the alloy droplets may be further fragmented to create a finer powder. When using a liquid for cooling, for example, water or oil may be used. When using a solid for cooling, for example, a rotating copper roll or a rotating aluminum plate may be used. However, the cooling liquid or solid is not limited to these, and various materials can be used.

[0020] Furthermore, in the powder manufacturing process described above, the powder shape and particle size of the soft magnetic powder can be adjusted by changing the manufacturing conditions.

[0021] The soft magnetic powder according to this embodiment has the properties shown in Figure 1. More specifically, the soft magnetic powder according to this embodiment has a glass transition temperature Tg, a first crystallization initiation temperature Tx1, and a second crystallization temperature Tx2. Here, the first crystallization initiation temperature Tx1 is a temperature that depends on the bcc-Fe(-Si) precipitation reaction (first crystallization reaction), and the second crystallization temperature Tx2 is a temperature that depends on the compound precipitation reaction (second crystallization reaction).

[0022] In this embodiment, the first crystallization initiation temperature Tx1 is within a predetermined range. Furthermore, in this embodiment, the first crystallization initiation temperature Tx1 and the glass transition temperature Tg have a predetermined relationship. Moreover, in this embodiment, the first crystallization initiation temperature Tx1 and the second crystallization temperature Tx2 have a predetermined relationship. By satisfying these requirements, when the soft magnetic powder of this embodiment undergoes heat treatment for nanocrystallization, self-heating due to endothermic reactions associated with the glass transition is suppressed, and fine nanocrystals can be sufficiently precipitated. The soft magnetic powder of this embodiment will now be described in detail.

[0023] In this embodiment, the first crystallization start temperature Tx1 is 400°C or higher and 475°C or lower. This is because, in soft magnetic powders produced by the atomization method, soft magnetic powders with Tx1 < 400°C have poor amorphous properties after rapid cooling, and good magnetic properties cannot be obtained. Furthermore, soft magnetic powders with Tx1 > 475°C tend to raise the temperature of the surrounding atmosphere due to the heat generated during nanocrystallization (heat treatment), which easily leads to grain coarsening and a decrease in soft magnetic properties.

[0024] In this embodiment, the first crystallization start temperature Tx1 is preferably 420°C or higher and 460°C or lower. This is because soft magnetic powder having a first crystallization start temperature Tx1 in this range exhibits good amorphous properties after rapid cooling, and the rise in ambient temperature due to heat generation during heat treatment is suppressed, resulting in good soft magnetic properties after heat treatment.

[0025] Furthermore, in this embodiment, the difference ΔTx = Tx1 - Tg between the first crystallization start temperature Tx1 and the glass transition temperature Tg is 50°C or less. This is because a supercooled liquid region is necessary to utilize the endothermic reaction associated with the glass transition during crystallization. Also, if ΔTx is too large, the endothermic reaction and the nanocrystallization (exothermic) reaction will not occur simultaneously, leading to crystal coarsening and a decrease in magnetic properties.

[0026] The difference ΔTx is preferably 20°C or higher. If ΔTx is 20°C or higher, the heat absorption amount due to the glass transition is sufficiently large, so that the temperature rise due to the nanocrystallization (exothermic) reaction can be effectively suppressed, and the soft magnetic properties are improved.

[0027] Furthermore, in the present embodiment, the difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 65°C or higher and 135°C or lower. This is because if ΔT is less than 65°C, the second crystallization (compound precipitation) reaction is promoted by the temperature rise due to the first crystallization reaction. Also, soft magnetic powder with ΔT exceeding 135°C has poor amorphousness and good soft magnetic properties cannot be obtained.

[0028] In the present embodiment, the difference ΔT is preferably 75°C or higher and 120°C or lower. For soft magnetic powder having a difference ΔT within this range, heat treatment is possible without causing the second crystallization (compound precipitation) reaction, the amorphousness is good, and the soft magnetic properties are good.

[0029] The soft magnetic powder according to the present embodiment has a composition formula Fe a Si b P c B d Cu x Cr y Nb z and has components represented by. Here, a, b, c, d, x, y, and z are numerical values that satisfy the conditions of 75.4 at% ≤ a ≤ 80.4 at%, 0 at% ≤ b ≤ 9 at%, 4.5 at% ≤ c ≤ 12 at%, 4 at% ≤ d ≤ 12 at%, 0.3 at% ≤ x ≤ 0.9 at%, and 0 at% ≤ y + z ≤ 5 at%.

[0030] In the soft magnetic powder according to the present embodiment, the Fe element is the main element and is an essential element responsible for magnetism. The higher the proportion of Fe, the more the magnetic flux density Bs can be improved and the raw material cost can be reduced. Also, if the proportion of Fe is less than 75.4 at%, Tx1 becomes high and ΔT becomes small. Therefore, heat treatment of the soft magnetic powder is difficult and the magnetic properties after heat treatment deteriorate. Also, if the proportion of Fe exceeds 80.4 at%, the amorphousness deteriorates and the soft magnetic properties deteriorate.

[0031] In this embodiment, the proportion of Fe element is preferably 77at% ≤ a ≤ 79at%. This is because soft magnetic powders with a Fe element proportion in this range have good amorphous properties (crystallinity less than 3%), a wide ΔT (75°C or higher), and good soft magnetic properties after heat treatment.

[0032] In the soft magnetic powder according to this embodiment, the Si element is responsible for amorphous phase formation. When the Si element is included in the soft magnetic powder, ΔT increases, allowing for stable heat treatment. However, if the Si content exceeds 9 at%, the amorphous phase formation ability decreases, and it becomes impossible to obtain a soft magnetic powder with amorphous as the main phase.

[0033] In the soft magnetic powder according to this embodiment, element P is an essential element responsible for amorphous phase formation. Element P facilitates the formation of a fine and uniform nanocrystalline structure after heat treatment, resulting in good magnetic properties. When the proportion of P falls below 4.5 at%, the amorphous phase formation ability decreases. In addition, it becomes more difficult to form a fine and uniform nanocrystalline structure after heat treatment, thus reducing the soft magnetic properties. On the other hand, as the proportion of P increases, Tx1 decreases. Furthermore, when the proportion of P exceeds 12 at%, the balance with other metalloid elements deteriorates, reducing the amorphous phase formation ability. Also, when the proportion of P exceeds 12 at%, the saturation magnetic flux density Bs decreases significantly.

[0034] In the soft magnetic powder according to this embodiment, element B is an essential element responsible for amorphous phase formation. If the proportion of B falls below 4 at%, it becomes difficult to form the amorphous phase by rapid cooling, and good magnetic properties cannot be obtained. Also, if the proportion of B increases, Tx1 increases. If the proportion of B exceeds 12 at%, the melting point becomes high, which is undesirable from a manufacturing standpoint, and the amorphous phase formation ability also decreases.

[0035] In the soft magnetic powder according to this embodiment, Cu is an essential element that contributes to the formation of the nanocrystalline phase. If the proportion of Cu is less than 0.3 at%, cluster deposition during heat treatment is small, making uniform nanocrystallization difficult. Conversely, if the proportion of Cu exceeds 0.9 at%, the ability to form amorphous regions decreases, making it difficult to obtain soft magnetic powder with high amorphous properties. In the soft magnetic powder according to this embodiment, the proportion of Cu is preferably less than 0.7 at%. This is because soft magnetic powders within this range have good amorphous properties, enable uniform nanocrystallization, and result in good soft magnetic properties after heat treatment.

[0036] In the soft magnetic powder according to this embodiment, Cr and Nb are not essential. However, the addition of Cr leads to the formation of an oxide film on the powder surface, improving corrosion resistance. The addition of Nb suppresses bcc grain growth during nanocrystallization, making it easier to form a fine nanocrystalline structure. However, the addition of Cr and Nb relatively reduces the proportion of Fe, lowering the saturation magnetic flux density Bs. It also reduces the amorphous formation ability. Therefore, it is preferable that the combined addition of Cr and Nb is 5 at% or less.

[0037] In the soft magnetic powder according to this embodiment, a portion of Fe may be substituted with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi, and rare earth elements. The inclusion of such elements facilitates uniform nanocrystallization after heat treatment. However, in order to keep the adverse effects of these elements on magnetic properties within an acceptable range, the proportion of these elements is preferably 3 at% or less of Fe.

[0038] In the soft magnetic powder according to this embodiment, the average particle size is preferably 1 μm or more and 20 μm or less. Furthermore, the degree of crystallinity of the soft magnetic powder after rapid cooling according to this embodiment is preferably 10% or less. These values ​​are chosen to obtain good magnetic properties after heat treatment.

[0039] Here, the rapid cooling rate by atomization is 10 3 The temperature should be K / s or higher. Preferably, 10 4 The cooling rate is 10 K / s or higher. 3 This is because if the temperature is less than K / s, the amount of initial crystals (mainly bcc-Fe) that precipitate increases, and the amount of amorphous phase decreases. Also, the composition of the amorphous phase in the soft magnetic powder deviates from the desired composition, and the glass transition temperature Tg does not appear. Furthermore, the first crystallization start temperature Tx1 shifts to the higher temperature side, and the temperature peak due to the first crystallization decreases.

[0040] Tables 1-8 show the results of evaluating the properties of several soft magnetic powders (hereinafter referred to as "samples") prepared as examples and comparative examples. The evaluation was performed as follows.

[0041] Thermal analysis was performed on each sample using differential scanning calorimetry (DSC). Specifically, the samples were thermally analyzed from 40°C to 730°C at a heating rate of 10°C / min. From this thermal analysis, the glass transition temperature (Tg), the first crystallization onset temperature (Tx1: bcc-Fe(-Si) precipitation), and the second crystallization onset temperature (Tx2: compound phase precipitation such as Fe-B and Fe-P) were determined for each sample.

[0042] Furthermore, each sample was introduced into an electric furnace and subjected to heat treatment in an inert atmosphere. The heat treatment was carried out by heating each sample to a predetermined temperature (listed in Table 1-8) and holding it for 30 minutes. For each sample, the precipitated phase was evaluated by X-ray diffraction (XRD) before and after heat treatment, and the proportion of the crystalline phase (crystallinity) was calculated by the whole-powder-pattern decomposition method (WPPD). In addition, the saturation magnetization of each sample was measured using a vibrating sample magnetometer (VSM), and the saturation magnetic flux density Bs of each sample was calculated from the measured saturation magnetization and the density of each sample. The density of each sample was determined using the Archimedes method. Furthermore, the particle size of the soft magnetic powder was evaluated using a laser particle size analyzer, and the average particle size was calculated from the evaluated particle size.

[0043] Furthermore, compacted magnetic cores were fabricated using each sample. The compacted magnetic cores were fabricated by hot press forming or cold press forming, as described later. For each fabricated compacted magnetic core, the core loss Pcv was measured using a BH analyzer to evaluate its magnetic properties. The measurement conditions were determined based on the particle size of each sample and the method of fabricating the compacted magnetic core (see Table 1-8). Based on the measured core loss Pcv, the samples were classified into examples and comparative examples. For details, in each of the examples in Table 1-6, the Pcv was 1250 kW / m². 3 The following samples were used as examples. Furthermore, in each of the items in Table 7-8, the Pcv was 300 kW / m². 3 The following samples were used as examples.

[0044] Cold press forming was performed as follows. First, a binder was added to the soft magnetic powder sample in a weight ratio of 3%, and the mixture was stirred to obtain granulated powder. Here, phenolic resin was used as the binder. Next, the particle size of the granulated powder was adjusted using a mesh with a mesh opening of 500 μm to obtain particle-size-adjusted granulated powder. Next, a compact was prepared using the particle-size-adjusted granulated powder. Specifically, 2.0 g of the particle-size-adjusted granulated powder was weighed, placed in a mold, and molded at a pressure of 490 MPa using a hydraulic automatic press. The shape of the compact was cylindrical with an outer diameter of 13 mm and an inner diameter of 8 mm. Next, the compact was heated in an inert atmosphere using an infrared heating device. Heating was carried out at a heating rate of 300 °C per minute until the predetermined heat treatment temperature (listed in Tables 1-5 and 7-8) was reached, and the heat treatment temperature was maintained for 20 minutes. This heat treatment hardened the binder and caused nanocrystallization of the soft magnetic powder, transforming the compact into a compacted magnetic core. Afterward, the compacted magnetic core was air-cooled and removed from the mold.

[0045] Hot press forming was carried out as follows. First, an insulating coating was formed on the surface of the soft magnetic powder sample to obtain insulating coated powder. The insulating coating was formed by immersing the soft magnetic powder in a solution of silicone resin diluted with methanol, and then volatilizing the methanol. The amount of silicone resin coating (solid content) was 1% by weight relative to the soft magnetic powder. Next, a binder was added to the insulating coated powder in an amount of 1% by weight and stirred to obtain granulated powder. Next, pre-forming was performed on the granulated powder to obtain a pre-molded body. Specifically, 2.0 g of granulated powder was weighed, placed in a mold, and pre-molded at a pressure of 150 MPa using a hydraulic automatic press. Next, main molding was performed on the pre-molded body. Specifically, a cylindrical mold with an outer diameter of 13 mm and an inner diameter of 8 mm was used, which had been preheated to a predetermined heat treatment temperature (listed in Table 6) using an electric heater. With the lower punch inserted into the mold, the pre-molded body was filled into the mold, and then the upper punch was inserted into the mold and a pressure of 1 GPa was applied. The pressurized state was maintained for 30 seconds to transform the pre-molded body into a compacted magnetic core. Afterward, the compacted magnetic core was removed from the mold.

[0046] In addition to phenolic resins and silicone resins, various organic and inorganic binders such as epoxy resins, polyamide resins, polyimide resins, melamine resins, polyurethane resins, and water glass can be used as binders in cold and hot press forming. The amount of binder should be appropriately determined considering the powder particle size, applicable frequency, and intended use.

[0047] (Examples 1-6 and Comparative Examples 1 and 2) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 1-6 and Comparative Examples 1 and 2, as described in Table 1 below. The raw materials were weighed to obtain the alloy compositions of Examples 1-6 and Comparative Examples 1 and 2 as described in Table 1, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by water atomization to produce soft magnetic powder with an average particle size of 8-14 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 1, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 1.

[0048] [Table 1]

[0049] Referring to Table 1, each of Examples 1-6 has a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In each of Examples 1-6, the first crystallization onset temperature Tx1 is in the range of 400°C to 475°C. Also, in each of Examples 1-6, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Also, in each of Examples 1-6, ΔTx is 20°C or more. Furthermore, in each of Examples 1-6, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is in the range of 65°C to 135°C. In addition, in each of Examples 1-6, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in each of Examples 1-6, the average particle size was 8-14 μm, and the average particle size was within the range of 1 μm to 20 μm. In addition, in each of Examples 1-6, the crystalline phase was the bcc-Fe phase.

[0050] As shown in Table 1, each of Examples 1-6 satisfies the compositional requirements of the present invention. On the other hand, Comparative Example 1 has an Fe content of 81.4 at%, which does not satisfy the compositional requirements of the present invention. Similarly, Comparative Example 2 has an Fe content of 74.9 at%, which also does not satisfy the compositional requirements of the present invention.

[0051] As shown in Table 1, the saturation magnetic flux density Bs for each of Examples 1-6 was 1.30 T or higher, and the core loss Pcv was 1250 kW / m 3 The following applies. In other words, each of Examples 1-6 has good magnetic properties.

[0052] In particular, the core loss Pcv for each of Examples 2-5 was 1000 kW / m², as shown in Table 1. 3 The following applies. In Examples 2-5, the first crystallization onset temperature Tx1 is within the range of 420°C to 460°C. Therefore, it is preferable that the first crystallization onset temperature Tx1 in the soft magnetic powder of the present invention is within the range of 420°C to 460°C.

[0053] Furthermore, the core loss Pcv for each of Examples 3-4 was 750 kW / m², as shown in Table 1. 3 The following applies. In addition, the crystallinity of Examples 3-4 is 1.3% and 0.5%, respectively, and Examples 3-4 exhibit excellent amorphous properties. In Examples 3-4, the proportion of Fe is within the range of 77 at% to 79 at%. Therefore, it is preferable that the proportion of Fe in the soft magnetic powder of the present invention is 77 at% or more and 79 at% or less.

[0054] On the other hand, Comparative Example 1, as shown in Table 1, does not have a glass transition temperature Tg. Also, in Comparative Example 1, the degree of crystallinity is 23.0%, which is well above 10%. Furthermore, in Comparative Example 2, the first crystallization onset temperature Tx1 is 480°C, which is above 475°C. Also, in Comparative Example 2, the difference ΔTx between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 53°C, which is above 50°C. Moreover, in Comparative Example 2, the crystalline phase includes not only the bcc-Fe phase but also the compound phase (Com.).

[0055] As shown in Table 1, in Comparative Example 1, although the saturation magnetic flux density Bs is 1.30 T or higher, the core loss Pcv is 1880 kW / m 3 and 1250kW / m 3 This significantly exceeds the previous result. Furthermore, in Comparative Example 2, although the saturation magnetic flux density Bs is 1.30T or higher, the core loss Pcv is 1350kW / m 3 and 1250kW / m 3 It surpasses that.

[0056] (Examples 7-12 and Comparative Example 3) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 7-12 and Comparative Example 3, as described in Table 2 below. The raw materials were weighed to obtain the alloy compositions of Examples 7-12 and Comparative Example 3 as described in Table 2, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by water atomization to produce soft magnetic powder with an average particle size of 8-14 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 2, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 2.

[0057] [Table 2]

[0058] Referring to Table 2, each of Examples 7-12 has a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In each of Examples 7-12, the first crystallization onset temperature Tx1 is within the range of 400°C to 475°C. Also, in each of Examples 7-12, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in each of Examples 7-12, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is within the range of 65°C to 135°C. In addition, in each of Examples 7-12, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in each of Examples 7-12, the average particle size was 8-14 μm, within the range of 1 μm to 20 μm. In addition, in each of Examples 7-12, the crystalline phase was the bcc-Fe phase.

[0059] As shown in Table 2, each of Examples 7-12 satisfies the compositional requirements of the present invention. On the other hand, Comparative Example 3 has a Si content of 9.5 at%, which does not satisfy the compositional requirements of the present invention (0 at% ≤ b ≤ 9 at%).

[0060] As shown in Table 2, the saturation magnetic flux density Bs for each of Examples 7-12 was 1.30 T or higher, and the core loss Pcv was 1250 kW / m 3 The following applies. In other words, each of Examples 7-12 has good magnetic properties.

[0061] In particular, the core loss Pcv for Examples 8-11 was 1000 kW / m², as shown in Table 2. 3 The following applies. In these Examples 8-11, ΔT is between 75°C and 120°C. Therefore, it is preferable that ΔT in the soft magnetic powder of the present invention is between 75°C and 120°C.

[0062] On the other hand, Comparative Example 3, as shown in Table 2, does not have a glass transition temperature Tg. Furthermore, in Comparative Example 3, the difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 140°C, which is greater than 135°C. In addition, in Comparative Example 3, the degree of crystallinity is 15.6%, which is greater than 15%.

[0063] As shown in Table 2, in Comparative Example 3, although the saturation magnetic flux density Bs is 1.30 T or higher, the core loss Pcv is 1500 kW / m 3 and 1250kW / m 3 It far exceeds that.

[0064] (Examples 13-17 and Comparative Examples 4 and 5) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 13-17 and Comparative Examples 4 and 5, as described in Table 3 below. The raw materials were weighed to obtain the alloy compositions of Examples 13-17 and Comparative Examples 4 and 5 as described in Table 3, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was gas atomized and then rapidly cooled with cooling water to produce soft magnetic powder with an average particle size of 8 to 14 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 3, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 3.

[0065] [Table 3]

[0066] Referring to Table 3, each of Examples 13-17 has a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In each of Examples 13-17, the first crystallization onset temperature Tx1 is in the range of 400°C to 475°C. Also, in each of Examples 13-17, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in each of Examples 13-17, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is in the range of 65°C to 135°C. In addition, in each of Examples 13-17, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in each of Examples 13-17, the average particle size was 8-14 μm, within the range of 1 μm to 20 μm. In addition, in each of Examples 13-17, the crystalline phase was the bcc-Fe phase.

[0067] As shown in Table 3, each of Examples 13-17 satisfies the compositional requirements of the present invention. On the other hand, Comparative Example 4 has a P content of 4 at%, which does not satisfy the compositional requirements of the present invention (4.5 at% ≤ c ≤ 12 at%). Also, Comparative Example 5 has a P content of 12.5 at%, which does not satisfy the compositional requirements of the present invention (4.5 at% ≤ c ≤ 12 at%).

[0068] As shown in Table 3, the saturation magnetic flux density Bs for each of Examples 13-17 was 1.30 T or higher, and the core loss Pcv was 1250 kW / m 3 The following applies. In other words, each of Examples 13-17 has good magnetic properties.

[0069] On the other hand, Comparative Example 4 does not have a glass transition temperature Tg, as shown in Table 3. Furthermore, in Comparative Example 5, the difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 60°C, which is below 65°C. Also, in Comparative Example 5, the degree of crystallinity after rapid cooling (as Q.) is 12.1%, which is above 10%. Moreover, in Comparative Example 5, the crystalline phase includes not only the bcc-Fe phase but also the compound phase (Com.).

[0070] As shown in Table 3, in Comparative Example 4, although the saturation magnetic flux density Bs is 1.30 T or higher, the core loss Pcv is 1430 kW / m 3 and 1250kW / m 3 It exceeds [the specified value]. In addition, in Comparative Example 5, although the saturation magnetic flux density Bs is 1.30T or higher, the core loss Pcv is 1550kW / m 3 and 1250kW / m 3 It far exceeds that.

[0071] (Examples 3, 18-21 and Comparative Examples 6, 7) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 3, 18-21, and Comparative Examples 6 and 7, as described in Table 4 below. The raw materials were weighed to obtain the alloy compositions of Examples 3, 18-21, and Comparative Examples 6 and 7 as described in Table 4, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by water atomization to produce soft magnetic powder with an average particle size of 8 to 14 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 4, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 4.

[0072] [Table 4]

[0073] Referring to Table 4, Examples 3 and 18-21 each have a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In both Examples 3 and 18-21, the first crystallization onset temperature Tx1 is within the range of 400°C to 475°C. Also, in both Examples 3 and 18-21, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in both Examples 3 and 18-21, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is within the range of 65°C to 135°C. In addition, in both Examples 3 and 18-21, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in both Example 3 and Examples 18-21, the average particle size was 8-14 μm, within the range of 1 μm to 20 μm. In addition, in both Example 3 and Examples 18-21, the crystalline phase was the bcc-Fe phase.

[0074] As shown in Table 4, in addition to Example 3, Examples 18-21 each satisfy the compositional requirements of the present invention. On the other hand, Comparative Example 6 has a proportion of B of 3.5 at%, which does not satisfy the compositional requirements of the present invention (4 at% ≤ d ≤ 12 at%). Also, Comparative Example 7 has a proportion of B of 12.5 at%, which does not satisfy the compositional requirements of the present invention (4 at% ≤ d ≤ 12 at%).

[0075] As shown in Table 4, the saturation magnetic flux density Bs for Example 3 and Examples 18-21 were 1.30 T or higher, and the core loss Pcv was 1250 kW / m². 3 In other words, both Example 3 and Examples 18-21 have good magnetic properties.

[0076] On the other hand, Comparative Examples 6 and 7, as shown in Table 4, do not have a glass transition temperature (Tg). Furthermore, the crystallinity of Comparative Examples 6 and 7 is 11.5% and 13.8%, respectively, both exceeding 10%.

[0077] As shown in Table 4, in Comparative Example 6, although the saturation magnetic flux density Bs is 1.30 T or higher, the core loss Pcv is 1260 kW / m 3 and 1250kW / m 3 It exceeds [the specified value]. Similarly, in Comparative Example 7, although the saturation magnetic flux density Bs is 1.30T or higher, the core loss Pcv is 1390kW / m 3 and 1250kW / m 3 It surpasses that.

[0078] (Examples 19, 22-27 and Comparative Examples 8, 9) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 19, 22-27, and Comparative Examples 8 and 9, as described in Table 5 below. The raw materials were weighed to obtain the alloy compositions of Examples 19, 22-27, and Comparative Examples 8 and 9 as described in Table 5, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by water atomization to produce soft magnetic powder with an average particle size of 8 to 14 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 5, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 5.

[0079] [Table 5]

[0080] Referring to Table 5, Examples 19 and 22-27 each have a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In both Examples 19 and 22-27, the first crystallization onset temperature Tx1 is within the range of 400°C to 475°C. Also, in both Examples 19 and 22-27, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in both Examples 19 and 22-27, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is within the range of 65°C to 135°C. In addition, in both Examples 19 and 22-27, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in both Example 19 and Examples 22-27, the average particle size was 8-14 μm, within the range of 1 μm to 20 μm. In addition, in both Example 19 and Examples 22-27, the crystalline phase was the bcc-Fe phase.

[0081] As shown in Table 5, in addition to Example 19, Examples 22-27 each satisfy the compositional requirements of the present invention. On the other hand, Comparative Example 8 has a Cu content of 1.0 at%, which does not satisfy the compositional requirements of the present invention (0.3 at% ≤ x ≤ 0.9 at%). Also, Comparative Example 9 has a Cu content of 0.2 at%, which does not satisfy the compositional requirements of the present invention (0.3 at% ≤ x ≤ 0.9 at%).

[0082] As shown in Table 5, the saturation magnetic flux density Bs for Examples 19 and 22-27 were 1.30 T or higher, and the core loss Pcv was 1250 kW / m². 3 In other words, both Example 19 and Examples 22-27 have good magnetic properties.

[0083] In particular, the core loss Pcv for Examples 19 and 24-27 was 1000 kW / m², as shown in Table 5. 3The following applies. In Examples 19 and 24-27, the proportion of Cu is less than 0.7 at%. Therefore, it is preferable that the proportion of Cu in the soft magnetic powder of the present invention is 0.3 at% or more and less than 0.7 at%.

[0084] On the other hand, Comparative Example 8, as shown in Table 5, does not have a glass transition temperature Tg. Also, in Comparative Example 8, the degree of crystallinity is 13.5%, which is above 10%. Furthermore, in Comparative Example 9, the difference between the first crystallization onset temperature Tx1 and the glass transition temperature Tg, ΔTx = Tx1 - Tg, is 62°C, which is below 65°C. Moreover, in Comparative Example 9, the crystalline phase includes not only the bcc-Fe phase but also the compound phase (Com.).

[0085] As shown in Table 5, in Comparative Example 8, although the saturation magnetic flux density Bs is 1.30 T or higher, the core loss Pcv is 1470 kW / m 3 and 1250kW / m 3 It exceeds [the specified value]. Similarly, in Comparative Example 9, although the saturation magnetic flux density Bs is 1.30T or higher, the core loss Pcv is 1520kW / m 3 and 1250kW / m 3 It surpasses that.

[0086] (Examples 19, 28-31 and Comparative Example 10) Industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, niobium, and electrolytic copper were prepared as raw materials for the soft magnetic powders of Examples 28-31 and Comparative Example 10, as described in Table 6 below. The raw materials were weighed to obtain the alloy compositions of Examples 28-31 and Comparative Example 10 as described in Table 6, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by high-pressure water atomization to produce soft magnetic powder with an average particle size of 3-8 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by hot press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 6, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 6.

[0087] [Table 6]

[0088] Referring to Table 6, Examples 19 and 28-31 each have a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In each of Examples 19 and 28-31, the first crystallization onset temperature Tx1 is within the range of 400°C to 475°C. Also, in each of Examples 19 and 28-31, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in each of Examples 19 and 28-31, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is within the range of 65°C to 135°C. In addition, in each of Examples 19 and 28-31, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in both Example 19 and Examples 28-31, the average particle size was 3-8 μm, within the range of 1 μm to 20 μm. In addition, in both Example 19 and Examples 28-31, the crystalline phase was the bcc-Fe phase.

[0089] As shown in Table 6, in addition to Example 19, Examples 28-31 each satisfy the compositional requirements of the present invention. On the other hand, Comparative Example 10 has a combined proportion of Cr and Nb of 5.5 at%, which does not satisfy the compositional requirements of the present invention (0 at% ≤ y + z ≤ 5 at%).

[0090] As shown in Table 6, the saturation magnetic flux density Bs for Examples 19 and 28-31 were 1.30 T or higher, and the core loss Pcv was 1250 kW / m². 3 In other words, both Example 19 and Examples 28-31 have good magnetic properties.

[0091] On the other hand, as shown in Table 6, Comparative Example 10 has a saturation magnetic flux density Bs that is below 1.25T and 1.30T, and a core loss Pcv of 1300kW / m 3 and 1250kW / m 3 It surpasses that.

[0092] (Examples 32-42) As raw materials for the soft magnetic powders of Examples 32-42 described in Table 7 below, industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, electrolytic copper, ferrocarbon, Co, zinc, Sn, Ni, Mn, Al, and Ti were prepared. The raw materials were weighed to obtain the alloy compositions of Examples 32-42 as described in Table 7, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was gas atomized and then rapidly cooled with cooling water to produce soft magnetic powder with an average particle size of 14-20 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, compacted magnetic cores were prepared by cold press molding using the prepared soft magnetic powder and their magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 7, and the saturation magnetic flux density Bs was measured by VSM for the heat-treated soft magnetic powder. Table 7 shows the results of the measurement and evaluation of the prepared soft magnetic powder.

[0093] [Table 7]

[0094] Referring to Table 7, each of Examples 32-42 has a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In each of Examples 32-42, the first crystallization onset temperature Tx1 is within the range of 400°C to 475°C. Also, in each of Examples 32-42, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in each of Examples 32-42, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is within the range of 65°C to 135°C. In addition, in each of Examples 32-42, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Furthermore, in each of Examples 32-42, the average particle size was 14-20 μm, within the range of 1 μm to 20 μm. In addition, in each of Examples 32-42, the crystalline phase was the bcc-Fe phase.

[0095] As shown in Table 7, in each of Examples 32-42, a portion of Fe (3 at% or less) is substituted with a predetermined element. Specifically, Examples 32 and 33 each contain C. Example 34 contains Co. Example 35 contains Zn. Examples 36 and 37 each contain Sn. Example 38 contains Ni. Example 39 contains Mn. Example 40 contains Al. Example 41 contains Ti. Example 42 contains O.

[0096] As shown in Table 7, in each of Examples 32-42, the saturation magnetic flux density Bs was 1.30 T or higher, and the core loss Pcv was 300 kW / m 3 The following applies. In other words, each of Examples 32-42 has good magnetic properties. Note that the measurement conditions for core loss Pcv in Table 7 are different from the measurement conditions for core loss Pcv in Tables 1-6.

[0097] (Example 43) As raw materials for the soft magnetic powder of Example 43 described in Table 8 below, industrial pure iron, ferrosilicon, ferroline, ferroboron, ferrochrome, and electrolytic copper were prepared. The raw materials were weighed to obtain the alloy composition of Example 43 described in Table 8, and the alloy molten metal was prepared by high-frequency induction melting in an argon atmosphere. Next, the prepared alloy molten metal was rapidly cooled by gas atomization to produce soft magnetic powder with an average particle size of 14-20 μm. The prepared soft magnetic powder was subjected to thermal analysis by DSC and evaluation of the crystalline phase by XRD. Furthermore, a compacted magnetic core was prepared by cold press molding using the prepared soft magnetic powder and its magnetic properties were evaluated. In addition, the prepared soft magnetic powder was heat-treated in an electric furnace in an argon atmosphere at the heat treatment temperatures shown in Table 8, and the saturation magnetic flux density Bs was measured by VSM on the heat-treated soft magnetic powder. The results of the measurement and evaluation of the prepared soft magnetic powder are shown in Table 8.

[0098] [Table 8]

[0099] Referring to Table 8, Example 43 has a glass transition temperature Tg, a first crystallization onset temperature Tx1, and a second crystallization temperature Tx2. In Example 43, the first crystallization onset temperature Tx1 is in the range of 400°C to 475°C. Also in Example 43, the difference ΔTx = Tx1 - Tg between the first crystallization onset temperature Tx1 and the glass transition temperature Tg is 50°C or less. Furthermore, in Example 43, the difference ΔT = Tx2 - Tx1 between the second crystallization onset temperature Tx2 and the first crystallization onset temperature Tx1 is in the range of 65°C to 135°C. In addition, in Example 43, the degree of crystallinity after rapid cooling (as Q.) is 10% or less. Also in Example 43, the average particle size is 14 to 20 μm, and is in the range of 1 μm to 20 μm.

[0100] As shown in Table 8, the first crystallization onset temperature Tx1 for Example 43 is 442°C. Example 43 was heat-treated at various temperatures between 400°C and 500°C. At all treatment temperatures, a saturation magnetic flux density Bs of 1.30T or higher and 300kW / m³ were achieved. 3The following core loss Pcv was obtained. From this, it can be seen that the soft magnetic powder of the present invention can obtain good magnetic properties even when heat treatment is performed at a temperature lower or higher than the first crystallization onset temperature Tx1. However, referring to Table 7 in addition to Table 8, when the heat treatment temperature is close to the first crystallization onset temperature Tx1, the core loss Pcv is 200 kW / m 3 The following applies. Therefore, it is preferable that the heat treatment temperature be close to the first crystallization onset temperature Tx1.

[0101] As described above, the compacted magnetic cores of Examples 1-43 have excellent magnetic properties. From this, it can be said that the soft magnetic powder of Examples 1-43 can undergo stable nanocrystallization and sufficiently precipitate fine nanocrystals.

[0102] Although several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes are possible without departing from the spirit of the present invention.

[0103] For example, the soft magnetic powder of the present invention may be one in which initial crystals have precipitated. In this case, low-grade, inexpensive materials can be used as raw materials. Furthermore, the amount of heat generated during heating can be suppressed. In addition, a high saturation magnetic flux density Bs can be expected.

[0104] Furthermore, although atomization was used to produce the soft magnetic powder in the above embodiment, other methods may be used. For example, a thin strip may be prepared from the molten alloy, and the strip may be pulverized to obtain the soft magnetic powder. In this case, a high saturation magnetic flux density Bs and a high permeability μ can be expected.

[0105] Furthermore, the soft magnetic powder of the present invention may have its surface coated with glass or the like. This is expected to improve electrical resistance and fluidity during the production of magnetic cores.

Claims

1. Soft magnetic powder, The soft magnetic powder has a glass transition temperature Tg, a first crystallization start temperature Tx1, and a second crystallization start temperature Tx2. The glass transition temperature Tg is 360°C or higher and 428°C or lower. The first crystallization start temperature Tx1 is 400°C or higher and 475°C or lower. The difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 65°C or more and 135°C or less. The soft magnetic powder is represented by the compositional formula Fe a Si b P c B d Cu x Cr y Nb z, 75.4at%≦a≦80.4at% 0at%≦b≦9at% 4.5at%≦c≦12at% 4at%≦d≦12at% 0.3at%≦x≦0.9at% 0at%≦y+z≦5at% That is Soft magnetic powder.

2. The soft magnetic powder according to Claim 1, The core loss is 1250 kW / m³ or less. Soft magnetic powder.

3. A soft magnetic powder according to claim 1 or claim 2, The difference between the first crystallization start temperature Tx1 and the glass transition temperature Tg, ΔTx = Tx1 - Tg, is 50°C or less. Soft magnetic powder.

4. A soft magnetic powder according to any one of claims 1 to 3, The first crystallization start temperature Tx1 is 420°C or higher and 460°C or lower. Soft magnetic powder.

5. A soft magnetic powder according to any one of claims 1 to 4, The difference ΔTx = Tx1 - Tg between the first crystallization start temperature Tx1 and the glass transition temperature Tg is between 20°C and 50°C. Soft magnetic powder.

6. A soft magnetic powder according to any one of claims 1 to 5, The difference ΔT = Tx2 - Tx1 between the second crystallization start temperature Tx2 and the first crystallization start temperature Tx1 is 75°C or higher. Soft magnetic powder.

7. A soft magnetic powder according to any one of claims 1 to 6, 77at%≦a≦79at% That is Soft magnetic powder.

8. The soft magnetic powder according to claim 7, A portion of the Fe, comprising 3 at% or less of the total composition, is substituted with one or more elements selected from Co, Ni, Zn, Zr, Hf, Mo, Ta, W, Ag, Au, Pd, K, Ca, Mg, Sn, Ti, V, Mn, Al, S, C, O, N, Bi, and rare earth elements. Soft magnetic powder.

9. A soft magnetic powder according to any one of claims 1 to 8, The average particle size is between 1 μm and 20 μm. Soft magnetic powder.

10. A soft magnetic powder according to any one of claims 1 to 9, The degree of crystallinity after rapid cooling is 10% or less. Soft magnetic powder.

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