Soft magnetic alloy particle, soft magnetic powder, powdered magnetic core and electronic component

Abstract

To provide a soft magnetic alloy particle which is included in soft magnetic powder and shows a small increase in coercive force even after applied with pressure and which enables reduction of core loss, etc., and to provide soft magnetic powder, a powdered magnetic core and an electronic component each including the soft magnetic alloy particle.SOLUTION: A soft magnetic alloy particle having Fe and Si is provided. In the cross section of the soft magnetic alloy particle, 1 to 20 nitride phases are observe, the area of each nitride phase is in the range of 0.0005 to 10 μm2, and the area ratio of the nitride phases observed in the cross section of the soft magnetic alloy particles is in the range of 0.1 to 2%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to soft magnetic alloy particles, soft magnetic alloy powder, dust cores, and electronic components. [Background technology]

[0002] In recent years, there has been a demand for lower power consumption and higher efficiency in electronic, information, and communication devices. Furthermore, these demands are becoming even stronger as we move toward a low-carbon society. Therefore, there is also a demand for reduced energy loss and improved power supply efficiency in the power supply circuits of electronic, information, and communication devices. When considering the use of crystalline soft magnetic powders with high saturation magnetic flux density (e.g., Patent Document 1) as materials for the magnetic cores of electronic components such as magnetic elements, reducing coercivity is an important issue. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-24289 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of the above circumstances, and its object is to provide soft magnetic alloy particles contained in a soft magnetic powder that exhibits a small increase in coercive force even after pressure is applied and that can reduce core loss, etc., as well as soft magnetic powders, powder cores, and electronic components that contain such particles. [Means for solving the problem]

[0005] In order to achieve the above object, soft magnetic alloy particles according to one aspect of the present invention comprise: Soft magnetic alloy particles having Fe and Si, 1 to 20 nitride phases are observed in the cross section of the soft magnetic alloy grain, The area of ​​each nitride phase is 0.0005 to 10 μm 2is within the range of The area ratio of the nitride phase observed in the cross section of the soft magnetic alloy grain is in the range of 0.1 to 2%.

[0006] When soft magnetic powder containing the above-mentioned soft magnetic alloy particles is pressed and molded into a predetermined shape, the rate of increase in coercivity after pressure molding can be reduced compared to the coercivity of the powder before pressure molding. This is thought to be because, in soft magnetic powder containing soft magnetic alloy particles containing a nitride phase, the presence of the nitride phase alleviates the stress caused by pressure molding, preventing an increase in coercivity. Furthermore, the presence of the nitride phase suppresses eddy currents, thereby reducing core loss, including eddy current loss. This is thought to be because the presence of the nitride phase improves powder resistance.

[0007] The particle size of the soft magnetic alloy grains may be preferably 4 μm or more, and the proportion of nitride phases present in the region within 2 μm from the surface or grain boundary of the soft magnetic alloy grain in the cross section of the soft magnetic alloy grain to the total nitride phases is preferably 45% to 95%, more preferably 50% to 95%, or even 80% to 90%. By configuring in this way, the rate of increase in coercivity after compaction can be further reduced.

[0008] The composition of the soft magnetic alloy particles is not particularly limited as long as they contain Fe and Si, but the soft magnetic alloy particles may further contain Co. By configuring them in this way, the rate of increase in coercivity after compaction can be further reduced.

[0009] The nitride phase preferably contains nitrogen in an amount of 20 atomic % or more, or 30 atomic % or more, and may contain silicon in addition to nitrogen.

[0010] The soft magnetic powder according to one embodiment of the present invention includes the soft magnetic alloy particles described above. The soft magnetic powder according to one embodiment of the present invention may also include soft magnetic particles other than the soft magnetic alloy particles described above. Preferably, the soft magnetic powder has a particle size of 0.0005 to 10 μm per particle, as an average of a predetermined number of particles sampled under predetermined conditions.2 The nitride phases having sizes within this range were observed in a range of 1 to 20 particles, and the area ratio of the nitride phases per particle was within a range of 0.1 to 2%.

[0011] The soft magnetic powder according to another aspect of the present invention is A soft magnetic powder comprising soft magnetic alloy particles having Fe and Si, An average of 1 to 20 nitride phases are observed in the cross section of the soft magnetic alloy grain, The area of ​​each nitride phase is 0.0005 to 10 μm on average. 2 is within the range of The average area ratio of the nitride phase observed in the cross section of the soft magnetic alloy grain is within the range of 0.1 to 2%.

[0012] When soft magnetic powder having such a structure is pressed and molded into a predetermined shape, the rate of increase in coercivity after pressure molding can be reduced compared to the coercivity of the powder before pressure molding. This is thought to be because, in soft magnetic powders containing soft magnetic alloy particles containing a nitride phase, the presence of the nitride phase alleviates the stress caused by pressure molding, preventing an increase in coercivity. Furthermore, the presence of the nitride phase suppresses eddy currents, thereby reducing eddy current loss. This is thought to be because the presence of the nitride phase improves powder resistance.

[0013] A powder magnetic core according to one aspect of the present invention includes the soft magnetic alloy particles described above.

[0014] An electronic component according to one aspect of the present invention includes the soft magnetic alloy particles described above. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an SEM image of a soft magnetic alloy particle according to one embodiment of the present invention. [Figure 2] FIG. 2 is an Fe mapping image of the soft magnetic alloy grain shown in FIG. [Figure 3] FIG. 3 is an N mapping image of the soft magnetic alloy grain shown in FIG. [Figure 4] FIG. 4 is a Si mapping image of the soft magnetic alloy grain shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] The following describes the embodiments.

[0017] The soft magnetic alloy powder according to this embodiment contains a large number of soft magnetic alloy particles 2, for example, as shown in FIG. 1. The particles 2 shown in FIG. 1 are composed of one or more crystallites. The average particle size of the particles 2 is not particularly limited, but may be, for example, 1 μm or more and 50 μm or less, or 4 μm or more. The average crystallite size of the crystallites is also not particularly limited, but may be, for example, 0.5 μm or more and 20 μm or less.

[0018] The presence of crystallites in the soft magnetic alloy particles 2 can be confirmed by observing a backscattered electron image with an SEM. There are no particular limitations on the magnification of the backscattered electron image, as long as the magnification and resolution are such that the above-mentioned microstructure of the soft magnetic alloy particles can be confirmed. The magnification may be, for example, 500 times or more and 10,000 times or less.

[0019] The soft magnetic alloy particles 2 contain at least Fe and Si, and may contain other elements such as Co, Al, Cr, C, S, Ti, V, Mn, Ni, and Cu. For example, the Si content may be 1 to 15 atomic %. Fe may be substituted with Co and Ni. The total of Fe, Co, and Ni may be 80 to 100 atomic %. Furthermore, Al may be 0 to 10 atomic %.

[0020] Furthermore, other additional elements may be contained within a range that does not significantly affect the properties of the soft magnetic powder containing the soft magnetic alloy particles 2. For example, the other additional elements may be contained in an amount of 5% by mass or less, or 1% by mass or less, respectively. Furthermore, the other additional elements may be contained in a total amount of 10% by mass or less, or 2% by mass or less.

[0021] Alternatively, the soft magnetic alloy particles 2 may contain only Fe, Si and unavoidable impurities. In this case, the content of the unavoidable impurities may be 2% by mass or less, or 1% by mass or less.

[0022] As shown in Fig. 1, preferably one or more nitride phases 4 are observed in the cross section of the particle 2. The area of ​​each nitride phase 4 is determined by randomly sampling 100 or more particles 2 contained in the powder, and is preferably 0.0005 to 10 µm on average. 2 Within the range of 0.0005 to 5 μm, more preferably 2 is within the range.

[0023] Similarly, particles 2 are randomly sampled, and an average of preferably 1 to 20, and more preferably 4 to 20, nitride phases are observed on the cross section of particle 2. Similarly, particles 2 are randomly sampled, and the average area ratio of nitride phases 4 observed on the cross section of particle 2 is preferably in the range of 0.1 to 2%, and more preferably in the range of 0.4 to 2%.

[0024] As shown in Figures 3 and 4, for example, from an SEM mapping image, the nitride phase 4 preferably contains at least silicon (Si) in addition to nitrogen (N), and preferably does not substantially contain Fe, as shown in Figure 2. The nitride phase may contain crystals having a diffraction pattern that can be indexed as Si3N4 in electron diffraction using a transmission electron microscope.

[0025] The ratio of N in the nitride phase 4 is preferably 20 atomic % or more, 30 atomic % or more, or 40 atomic % or more. The ratio of Si in the nitride phase 4 is preferably 10 atomic % or more, or 50 atomic % or more, where the total of elements other than nitrogen contained in the nitride phase 4 is taken as 100 atomic %. The content of Fe in the nitride phase 4 is preferably 20 atomic % or less.

[0026] The nitride phase 4 may contain elements that constitute the soft magnetic particles, such as Co, Cr, Al, C, and S, in a total amount of 50 atomic % or less. These analyses and measurements can be performed using EPMA, SEM-EDX, STEM-EDX, or the like.

[0027] As shown in FIG. 1 , nitride phases 4 are often observed near the grain boundaries or surfaces of soft magnetic alloy particles 2. While there are no particular limitations on the particle size, the particle size of soft magnetic alloy particles 2 is preferably 1 μm or greater, or even 4 μm or greater. In the cross section of soft magnetic alloy particles 2, the percentage of nitride phases present within 2 μm from the surface or grain boundaries of soft magnetic alloy particles 2 relative to the total nitride phases is preferably 45% to 95%, more preferably 50% to 95%, or even 80% to 90%. This configuration further reduces the rate of increase in coercivity after compaction. The presence of nitride phases within 2 μm from the surface or grain boundaries of soft magnetic alloy particles 2 can be confirmed, for example, by the shortest distance from the surface or grain boundaries to the nitride phase being 2 μm or less, as indicated by the arrows in FIG. 1 .

[0028] The soft magnetic powder according to this embodiment may contain other soft magnetic powders. The other soft magnetic powders may be soft magnetic powders with different average particle sizes, or may be soft magnetic powders with different compositions from the soft magnetic powders described above. These other soft magnetic powders may be composed solely of soft magnetic particles that do not contain the nitride phase described above. The soft magnetic powder according to this embodiment preferably contains 20% by mass or more, more preferably 80% by mass or more, of soft magnetic alloy particles belonging to the soft magnetic powders having the above-described composition.

[0029] The soft magnetic alloy particles belonging to the soft magnetic powder having the above-described structure are particles in which 1 to 20 nitride phases 4 are observed in the cross section of the particle 2, and the area of ​​each nitride phase 4 is 0.0005 to 10 μm 2 The area ratio of the observed nitride phase 4 is in the range of 0.1 to 2%.

[0030] In a powder magnetic core constructed using the soft magnetic powder according to this embodiment, it is preferable that in a cross section where 200 or more magnetic particles are observed, soft magnetic alloy particles of the above-described configuration are contained in an amount of at least 10% by number.

[0031] An oxide film may be present on the surface of the soft magnetic alloy particles 2. For example, the thickness of the oxide film may be 5.0 nm or less, or 3.0 nm or less. The thinner the oxide film, the easier it is to improve the density of a dust core containing the soft magnetic alloy particles 2.

[0032] An example of a method for producing a soft magnetic powder containing soft magnetic alloy particles according to this embodiment will be described below, but the method for producing a soft magnetic powder according to this embodiment is not limited to the method described below. Note that in this embodiment, a powder is defined as a collection of substances containing a plurality of particles.

[0033] First, the raw material for the soft magnetic powder is prepared. The raw material may be a simple substance such as a metal, or an alloy. There are no particular restrictions on the form of the raw material. For example, it may be in the form of an ingot, chunk, or shot (particle).

[0034] Next, the prepared raw materials are weighed and mixed. At this time, the raw materials are weighed so as to obtain a soft magnetic powder of the desired composition. The mixed raw materials are then melted and mixed to obtain a melt. There are no particular restrictions on the equipment used for melting and mixing. For example, a crucible or the like may be used.

[0035] Then, soft magnetic powder is produced from the melt. There are no particular limitations on the method for producing soft magnetic powder from the melt, but for example, gas atomization, rotating disk method, and water atomization method can be used. Among these, gas atomization method involves supplying the melt as a continuous fluid through a nozzle or the like, and then causing high-pressure gas to collide with the supplied melt to rapidly cool it, thereby producing soft magnetic powder.

[0036] Next, the obtained soft magnetic powder is heat-treated under appropriate heat treatment conditions, whereby a soft magnetic powder containing the soft magnetic alloy particles according to this embodiment can be obtained.

[0037] Preferred heat treatment conditions vary depending on the composition of the target soft magnetic powder, but typically the holding temperature during heat treatment is preferably 800° C. to 1100° C., more preferably 800° C. to 1000° C. The holding time is preferably 10 minutes to 6 hours, more preferably 30 minutes to 5 hours.

[0038] Furthermore, the cooling rate to 300°C after the heat treatment is set to 0.1°C / s or more and 10°C / s or less. The heat treatment is preferably carried out in an atmosphere containing nitrogen gas, and may also contain an inert gas such as argon. The atmospheric pressure of the soft magnetic powder during the heat treatment is preferably 0.08 to 0.45 kPa, more preferably 0.1 kPa to 0.45 kPa, in gauge pressure. The gauge pressure refers to the pressure obtained by subtracting atmospheric pressure from absolute pressure (pressure when an absolute vacuum is 0 Pa).

[0039] In particular, by maintaining the heat treatment at a high temperature as described above and increasing the atmospheric pressure (gauge pressure), it is possible to obtain soft magnetic alloy particles 2 having the nitride phase 4 of the above-described structure.

[0040] By the above method, a soft magnetic powder containing the soft magnetic alloy particles according to this embodiment can be obtained. In addition, a dust core can be obtained by a method normally used for the soft magnetic powder according to this embodiment. There are no particular limitations on the method for obtaining the dust core.

[0041] A soft magnetic powder obtained by mixing the soft magnetic powder according to this embodiment with another soft magnetic metal powder may be used to obtain a dust core. There are no particular restrictions on the type of other soft magnetic metal powder. For example, a soft magnetic metal powder having a smaller average particle size than the soft magnetic powder according to this embodiment may be used. The average particle size of the soft magnetic metal powder having a smaller average particle size may be 0.5 μm or more and 5 μm or less. There are no particular restrictions on the material of the soft magnetic metal powder having a smaller average particle size. For example, metals such as pure iron and alloys such as permalloy may be used.

[0042] When the soft magnetic powder according to this embodiment is mixed with the soft magnetic metal powder having a small average particle size, the ratio of the soft magnetic powder according to this embodiment is not particularly limited. For example, it may be 50 mass % or more.

[0043] The dust core according to this embodiment has a relatively small coercive force, and coil components such as inductors, reactors, and motors can be obtained by commonly used methods. In particular, this embodiment provides coil components with high saturation current, low coil resistance, and low loss at high frequencies. Furthermore, when the dust core according to this embodiment is used, it is easy to miniaturize the coil components. There are no particular limitations on the method for obtaining the coil components. [Example]

[0044] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0045] Sample numbers 1 to 9 [Preparation of soft magnetic powder] First, ingots, chunks, or shots of elemental Fe and elemental Si were prepared. Next, elemental Fe and elemental Si were mixed to obtain the Si content shown in Table 1, and placed in a crucible placed in a gas atomization device. Next, in an inert atmosphere, the crucible was heated to 1500°C or higher by high-frequency induction using a work coil installed outside the crucible, and the ingots, chunks, or shots in the crucible were melted and mixed to obtain a molten liquid.

[0046] Next, the melt in the crucible was supplied from a nozzle provided in the crucible, and simultaneously, a gas of 1 to 10 MPa was collided with the supplied melt to rapidly cool it, thereby producing Fe—Si-based soft magnetic alloy powders having the compositions shown in Tables 1 and 2. In all soft magnetic powders, the average particle size of the soft magnetic alloy particles was adjusted to 25 μm.

[0047] The obtained soft magnetic powder was then subjected to a heat treatment. The heat treatment conditions for each sample are shown in Table 1. The cooling rate from the holding temperature to 300°C during the heat treatment was 1°C / sec in all cases, and the pressure in Table 1 is a gauge pressure.

[0048] [Evaluation of soft magnetic powder] (Evaluation of magnetic properties) The coercive force Hc of the soft magnetic powder after heat treatment was measured. The coercive force was measured using an Hc meter, and the results are shown in Table 1. In the table, the coercive force of the powder in an unpressurized state is indicated as Hc1, and the coercive force of the powder in an unpressurized state is indicated as Hc2. 2 After pressing for one minute, the coercive force of the crushed powder was recorded as Hc2. The smaller Hc1 is, the more preferable, and in Tables 1 to 3, it is preferably less than 5.0 Oe. The smaller Hc2 is, the more preferable, and in Tables 1 to 3, it is preferably less than 10.0 Oe. Table 1 also shows the ratio Hc2 / Hc1 of the coercive force Hc2 after pressing to the coercive force Hc1 without pressing for each sample. The smaller the ratio Hc2 / Hc1, the more preferable, and it is preferably 2.1 or less.

[0049] (Observation of nitride phase) The soft magnetic powder was mixed with resin, hardened to form a compound, and the resulting cross section was polished and observed. Specifically, the soft magnetic powder was mixed with thermosetting epoxy resin, cut into a sheet approximately 300 μm thick, and hardened at 120°C. The cross section was polished using an Ar ion milling device (Hitachi High-Tech IM-4000) and observed using an SEM (Hitachi High-Tech SU5000) at an accelerating voltage of 5 kV.

[0050] For example, as shown in Figure 1, the nitride phase 4 is observed with a dark contrast in the backscattered electron image. Furthermore, the composition of the segregated phase (nitride phase) can be identified by analyzing it with an EDX (HORIBA E-max) attached to the SEM. The EDX analysis was performed at an accelerating voltage of 10 kV. Furthermore, the backscattered electron image obtained by observing the compound at a magnification of 2000x using a backscattered electron detector attached to the SEM confirmed that the soft magnetic alloy particles contained in the soft magnetic powder have crystallites.

[0051] Similarly, the powder magnetic core was also subjected to cross-sectional polishing using an Ar ion milling device, and the nitride phase was identified by observing the cross-sectional surface with a backscattered electron image using an SEM and analyzing the surface with EDX.

[0052] In addition, 100 or more particles were randomly sampled from the cross-sectional photograph of the soft magnetic alloy particles in the soft magnetic powder, and the average cross-sectional area of ​​the nitride phase 4 (average cross-sectional area), the average number of nitride phases per particle, and the average area ratio per particle were measured. The results are shown in Table 1. Note that for particles with a cross-sectional area of ​​0.0005 μm 2 The number of nitride phases described below was not counted, and they were not included in the measurement of cross-sectional area or area ratio.

[0053] [Table 1]

[0054] Rating 1 From the results shown in Table 1, no nitride phase was observed in Sample 1, for which the atmospheric pressure during heat treatment was 0 kPa. 2 The above nitride phases were observed, and it was found that the coercive force Hc2 of the powder after pressure application was smaller than that of Sample 1, and that Hc2 / Hc1 was also smaller. In Sample 2, which was heat-treated at an atmospheric pressure of 0.05 kPa, the cross-sectional area of ​​the nitride phase was 0.0005 μm 2 Since only nitride phases below 0.0005 μm were observed, the number of particles was not counted. 2In sample 2, in which only the following nitride phases were observed, Hc2 / Hc1 was not reduced.

[0055] Furthermore, from the results in Table 1, it was confirmed that it is possible to control the number of nitride phases by changing the atmospheric pressure (gauge pressure) during heat treatment. It was confirmed that Hc2 / Hc1 can be reduced by having an average number of nitride phases per particle, preferably 1 to 20, in the cross section of particle 2. When the average number of nitride phases is less than 1 or 20 or more, the effect of reducing Hc2 / Hc1 was not observed.

[0056] Sample numbers 10 to 14 Soft magnetic metal powder was prepared in the same manner as sample No. 5, except that the holding time during heat treatment was changed to the value shown in Table 2, and evaluations were performed in the same manner as sample No. 5. The results are shown in Table 2.

[0057] [Table 2]

[0058] Rating 2 From the results shown in Table 2, it was confirmed that it is possible to control the area ratio of the nitride phase by changing the holding time during heat treatment. It was also confirmed that Hc2 / Hc1 can be reduced when the area ratio of the nitride phase is preferably in the range of 0.1 to 2%. It was further confirmed that Hc2 / Hc1 can be reduced when the area ratio is in the range of 0.5 to 2%.

[0059] Sample numbers 15 to 18 Soft magnetic metal powders were prepared in the same manner as sample No. 5, except that the holding temperature during heat treatment was changed to the value shown in Table 3, and evaluations were carried out in the same manner as sample No. 5. The results are shown in Table 3.

[0060] [Table 3]

[0061] Rating 3 From the results shown in Table 3, it was confirmed that the cross-sectional area of ​​the nitride phase can be controlled by changing the holding temperature during heat treatment.

[0062] Sample numbers 19 to 21 Soft magnetic metal powders were prepared and evaluated in the same manner as in Sample Nos. 1, 5, and 8, except that Fe—Si alloy powders with an average particle size of 1 μm were used as raw materials. The results are shown in Table 4.

[0063] Sample numbers 22 to 24 Soft magnetic metal powders were prepared and evaluated in the same manner as in Sample Nos. 1, 5, and 8, except that Fe—Si alloy powder with an average particle size of 4 μm was used as the raw material. The results are shown in Table 4.

[0064] Sample numbers 25 to 27 Soft magnetic metal powders were prepared and evaluated in the same manner as in Sample Nos. 1, 5, and 8, except that Fe—Si alloy powders with an average particle size of 10 μm were used as raw materials. The results are shown in Table 4.

[0065] Sample numbers 28 to 30

[0066] Soft magnetic metal powders were prepared and evaluated in the same manner as in Sample Nos. 1, 5, and 8, except that Fe—Si alloy powders with an average particle size of 50 μm were used as raw materials. The results are shown in Table 4.

[0067] [Table 4]

[0068] Rating 4 From the results shown in Table 4, it was confirmed that even when the average particle size of the soft magnetic powder is different, the soft magnetic metal powder of the example satisfying the predetermined constitution can maintain a low coercive force of the powder after pressure is applied, compared to each comparative example having the same particle size. Furthermore, from the results of Tables 3 and 4, it can be seen that the cross-sectional area of ​​the nitride phase is preferably 0.0005 μm 2 More than 10μm 2 It was confirmed that Hc2 / Hc1 could be reduced within the following range.

[0069] In addition, the cross-sections of the compounds of the soft magnetic powders of sample numbers 4 to 8, 11 to 13, and 16 to 18 were photographed using an SEM, and EDX mapping images of each element were taken.It was confirmed that in cross-sections where 50 or more magnetic particles were observed, soft magnetic alloy particles of the specific composition shown below were contained in a number ratio of at least 50% or more.

[0070] The soft magnetic alloy particles having a specific structure are particles in which an average number of nitride phases 4 per particle is observed to be 1 to 20 in a cross section of the particle 2, and the area of ​​each nitride phase 4 is 0.0005 to 10 μm 2 The area ratio of the observed nitride phase 4 is in the range of 0.1 to 2%.

[0071] Sample numbers 31 to 34 Soft magnetic metal powder was prepared and evaluated in the same manner as in sample number 5, except that the temperature rise rate during heat treatment was changed to the value shown in Table 5. The results are shown in Table 5.

[0072] For the examples of sample numbers 1, 5, and 31 to 34, the average proportion of the nitride phase present in the region within 2 μm from the surface or grain boundary of each of 50 or more soft magnetic alloy particles in which the nitride phase was observed was measured. The results are shown in Table 5.

[0073] [Table 5]

[0074] Rating 5 From the results shown in Table 5, it was confirmed that the area ratio of the nitride phase present near the grain boundaries or particle surfaces of the particles can be controlled by changing the heating rate during heat treatment. It was also confirmed that Hc2 / Hc1 can be further reduced by having the nitride phases present in the surface of the soft magnetic alloy particles 2 or within 2 μm from the grain boundaries, with the number ratio of the nitride phases to the total nitride phases being preferably 45% to 95%, more preferably 50% to 95%, or even 80% to 90%.

[0075] Sample numbers 35 and 36 The soft magnetic powder has a composition of (Fe 90 Co 10 ) 91.4 Si 8.6 Soft magnetic metal powders were prepared in the same manner as in Sample Nos. 1 and 5, except that Fe, Co, and Si were mixed and used as raw materials so that the composition satisfies the following criteria: soft magnetic metal powders were prepared in the same manner as in Sample Nos. 1 and 5, and evaluations were performed in the same manner. The results are shown in Table 6.

[0076] Sample Nos. 37 and 38 The soft magnetic powder has a composition of (Fe 80 Co 20 ) 91.4 Si 8.6 Soft magnetic metal powders were prepared and evaluated in the same manner as in Sample Nos. 1 and 5, except that Fe, Co, and Si were mixed together and used as raw materials so that the composition satisfies the following criteria: The results are shown in Table 6.

[0077] Sample Nos. 39 and 40 The soft magnetic powder has a composition of (Fe 70 Co 30 ) 91.4 Si 8.6 Soft magnetic metal powders were prepared in the same manner as in Sample Nos. 1 and 5, except that Fe, Co, and Si were mixed together and used as raw materials so that the composition satisfies the following criteria: 1. Fe, Co, and Si were mixed together and evaluated in the same manner as in Sample Nos. 1 and 5. The results are shown in Table 6.

[0078] Sample Nos. 41 and 42 The soft magnetic powder has a composition of (Fe 60 Co40 ) 91.4 Si 8.6 Soft magnetic metal powders were prepared in the same manner as in Sample Nos. 1 and 5, except that Fe, Co, and Si were mixed together and used as raw materials so that the composition satisfies the following criteria: 1. Fe, Co, and Si were mixed together and evaluated in the same manner as in Sample Nos. 1 and 5. The results are shown in Table 6.

[0079] Sample Nos. 43 and 44 The soft magnetic powder has a composition of (Fe 40 Co 60 ) 91.4 Si 8.6 Soft magnetic metal powders were prepared in the same manner as in Sample Nos. 1 and 5, except that Fe, Co, and Si were mixed together and used as raw materials so that the composition satisfies the following criteria: 1. Fe, Co, and Si were mixed together and evaluated in the same manner as in Sample Nos. 1 and 5. The results are shown in Table 6.

[0080] [Table 6]

[0081] Rating 6 From the results shown in Table 6, it was confirmed that when the soft magnetic powder contains Co, the soft magnetic metal powder of the example that satisfies the specified configuration can further reduce Hc2 / Hc1 compared to each comparative example that has the same composition.

[0082] Sample numbers 45 to 48 Soft magnetic metal powder was prepared and evaluated in the same manner as in Sample No. 5, except that the heat treatment atmosphere was changed as shown in Table 7. The results are shown in Table 7.

[0083] [Table 7]

[0084] Rating 7 From the results shown in Table 7, it was confirmed that even when the nitrogen concentration in the nitride phase is different, the soft magnetic metal powder of the example that satisfies the specified configuration can maintain a low coercive force after pressure is applied. It was also confirmed that the Hc2 / Hc1 can be particularly reduced when the nitrogen ratio in the nitride phase 4 is preferably 20 atomic % or more, or 30 atomic % or more.

[0085] Sample numbers 49 to 156 Soft magnetic powders were prepared in the same manner as sample number 1 or 5, and evaluated in the same manner, except that Fe, Si, Cr, Co, C, Al, S, Ti, V, Mn, Ni, and Cu were mixed and used as raw materials so that the soft magnetic powders had compositions shown in Tables 8 to 11. The results are shown in Tables 8 to 11.

[0086] [Table 8]

[0087] [Table 9]

[0088] [Table 10]

[0089] [Table 11]

[0090] Rating 8 From the results shown in Tables 8 to 11, it was confirmed that even when the composition of the soft magnetic powder is different, the soft magnetic metal powder of the example that satisfies the specified configuration can reduce Hc2 / Hc1 compared to the comparative example with the same composition.

[0091] Sample numbers 157 and 158 For the soft magnetic alloy powders of Sample Nos. 1 and 5, dust cores were produced and evaluated according to the procedure described below.

[0092] [Machining of dust cores] Epoxy resin was added as a binder to the heat-treated soft magnetic powder to produce granulated powder. The type and amount of epoxy resin added were determined appropriately depending on the average particle size of each soft magnetic powder. This granulated powder was then molded under a molding pressure of 8 ton / cm to form a toroidal shape with an outer diameter of 18 mm, an inner diameter of 10 mm, and a height of 5 mm. 2 Next, the compact was held at 180°C for 3 hours in an air atmosphere to harden the resin, thereby obtaining a toroidal dust core.

[0093] [Evaluation of dust cores] (Measurement of magnetic permeability) The relative permeability μ' at a frequency of 1 MHz was measured for the dust cores produced using the soft magnetic powders of sample number 1 and sample number 5. The relative permeability μ' was measured using an RF impedance material analyzer (4991A manufactured by Agilent Technologies). The results are shown in Table 12.

[0094] (Core loss (power loss) Pcv measurement) For the dust cores produced using the soft magnetic powders of Sample No. 1 and Sample No. 5, the primary winding was wound 30 times and the secondary winding was wound 10 times. Then, the core loss Pcv was measured at a measurement frequency of 3 MHz and a magnetic flux density of 10 mT. The Pcv measurement was performed using a BH analyzer (SY-8218 manufactured by Iwasaki Electric Co., Ltd.). The results are shown in Table 12.

[0095] Sample numbers 159, 161, 163, 165, and 167 Powder cores were prepared in the same manner as sample number 157, and evaluated in the same manner, except that soft magnetic powder of sample number 1 was coated with a coating film of the material and thickness shown in Table 12. The results are shown in Table 12. The coercive forces Hc1 and Hc2 of the coated powder for each sample were also measured. The coercive forces were measured using an Hc meter. The results are shown in Table 12.

[0096] Sample numbers 160, 162, 164, 166, and 168 Powder cores were produced and evaluated in the same manner as for sample number 158, except that soft magnetic powder of sample number 5 was coated with a coating film made of the material and with the thickness shown in Table 12. The results are shown in Table 12. Table 12 also shows the results of measuring the coercive forces Hc1 and Hc2 of the coated powder for each sample.

[0097] [Table 12]

[0098] Rating 9 From the results shown in Table 12, it was confirmed that although Hc1 increased slightly after coating compared to before coating, the coated powder maintained the same Hc2 / Hc1 relationship as sample numbers 157 and 158 before coating. The smaller the ratio Hc2 / Hc1, the better, and it was preferably less than 2.0. It was also confirmed that the magnetic permeability was improved and core loss could be reduced in dust cores using the soft magnetic metal powder of the example satisfying the specified configuration. Furthermore, even when a coating film was formed on the surface of the soft magnetic alloy particles, it was confirmed that the magnetic permeability was improved and core loss could be reduced in dust cores using the soft magnetic metal powder of the example satisfying the specified configuration, and that it was possible to reduce core loss.

[0099] Sample numbers 169, 171, 173, and 175 A powder magnetic core was prepared in the same manner as sample number 157, and evaluated in the same manner, except that a powder was used in which the soft magnetic powder of sample number 1 and iron powder having an average particle size of 1 μm were mixed in a mass ratio shown in Table 13. The results are shown in Table 13.

[0100] Sample numbers 170, 172, 174, and 176 A powder magnetic core was prepared in the same manner as sample number 158, and evaluated in the same manner, except that a powder was used in which the soft magnetic powder of sample number 5 and iron powder having an average particle size of 1 μm were mixed in a mass ratio shown in Table 13. The results are shown in Table 13.

[0101] [Table 13]

[0102] Sample numbers 177, 179, and 181 A powder magnetic core was prepared in the same manner as sample number 157, and evaluated in the same manner, except that a powder was used that was a mixture of the soft magnetic powder of sample number 1, a powder made of Fe—Si—B having an average particle size of 3 μm, and an iron powder having an average particle size of 1 μm, in a mass ratio shown in Table 14. The results are shown in Table 14.

[0103] Sample numbers 178, 180, and 182 A powder magnetic core was prepared in the same manner as sample number 158, and evaluated in the same manner, except that a powder was used that was a mixture of the soft magnetic powder of sample number 5, a powder made of Fe—Si—B having an average particle size of 3 μm, and a pure iron powder having an average particle size of 1 μm, in a mass ratio shown in Table 14. The results are shown in Table 14.

[0104] [Table 14]

[0105] Rating 11 From the results shown in Tables 13 and 14, it was confirmed that even when a powder core was produced by mixing the soft magnetic powder of the example with another soft magnetic powder, the magnetic permeability was improved and there was an effect in reducing core loss that corresponded to the compounding ratio of the powder of the example. [Explanation of symbols]

[0106] 2… Soft magnetic alloy particles 4... Nitride phase

Claims

1. Soft magnetic alloy particles having Fe and Si, 1 to 20 nitride phases are observed in the cross section of the soft magnetic alloy grain, The area of ​​each nitride phase is 0.0005 to 10 μm 2 is within the range of A soft magnetic alloy grain in which the area ratio of the nitride phase observed in the cross section of the soft magnetic alloy grain is within the range of 0.1 to 2%.

2. The soft magnetic alloy particles according to claim 1 , further comprising Co.

3. The soft magnetic alloy particles of claim 1 , wherein the nitride phase comprises silicon.

4. 2. The soft magnetic alloy particles according to claim 1, wherein the nitride phase contains 30 atomic % or more of nitrogen.

5. A soft magnetic powder comprising the soft magnetic alloy particles according to any one of claims 1 to 4.

6. A soft magnetic powder comprising soft magnetic alloy particles having Fe and Si, an average of 1 to 20 nitride phases are observed in the cross section of the soft magnetic alloy grain; The area of ​​each nitride phase is 0.0005 to 10 μm on average. 2 is within the range of A soft magnetic powder in which the average area ratio of the nitride phase observed in the cross section of the soft magnetic alloy particle is within the range of 0.1 to 2%.

7. A powder magnetic core comprising the soft magnetic alloy particles according to any one of claims 1 to 4.

8. An electronic component comprising the soft magnetic alloy particles according to any one of claims 1 to 4.

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