Magnetic material, dust core, inductor, and method for manufacturing dust core

Abstract

This magnetic material includes an Fe-Si-Al-based metal magnetic powder (12). The Fe-Si-Al-based metal magnetic powder (12) has a relationship in which when the Si content is A wt% and the Al content is B wt%, 7.2 wt%≤A≤8.1 wt%, 6.0 wt%≤B≤7.5 wt%, and 2A+B≤22.7 wt% are satisfied.

Description

[Technical field]

[0001] The present disclosure relates to a magnetic material, a powder magnetic core including the magnetic material, an inductor including the powder magnetic core, and a method for manufacturing the powder magnetic core. [Background technology]

[0002] Magnetic materials containing Fe-Si-Al metal powder are known as materials for forming the powder cores of inductors. Magnetic materials are required to reduce magnetic loss, which leads to energy loss.

[0003] Conventional magnetic materials containing Fe-Si-Al alloy powder (so-called Sendust alloy powder) can reduce hysteresis loss, which is one type of magnetic loss. In addition, the magnetic material containing Fe-Si-Al soft magnetic powder described in Patent Document 1 can reduce magnetic loss in the high temperature range where an inductor operates. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5374537 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while conventional magnetic materials containing sendust alloy powders can reduce hysteresis loss at room temperature, they have a problem of increasing hysteresis loss at high temperatures. Also, the magnetic material containing the soft magnetic powder described in Patent Document 1 can reduce magnetic loss at high temperatures, but has a problem of decreasing magnetic permeability under conditions where a large current flows, i.e., poor DC superposition characteristics.

[0006] In view of the above-mentioned problems, an object of the present disclosure is to provide a magnetic material or the like that suppresses an increase in magnetic loss in a high temperature range and has excellent DC bias characteristics. [Means for solving the problem]

[0007] A magnetic material according to one embodiment of the present disclosure is a magnetic material containing an Fe—Si—Al-based metal magnetic powder, the Fe—Si—Al-based metal magnetic powder satisfying the following relationship: Si content is A weight % and Al content is B weight %. <7.6 weight%, and, 6.0wt%≦B≦7.5wt% Noseki This position has a role.

[0008] A powder magnetic core according to one embodiment of the present disclosure includes the magnetic material.

[0009] An inductor according to one aspect of the present disclosure includes a magnetic core formed from the powder magnetic core described above, and a coil portion at least a portion of which is provided inside the magnetic core.

[0010] A method for producing a powder magnetic core according to one embodiment of the present disclosure is a method for producing the above-mentioned powder magnetic core, and includes a step of molding the powder magnetic core by pressure molding the magnetic material, and a step of heat treating the molded powder magnetic core at a temperature of 650°C or higher and 800°C or lower. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a magnetic material or the like that suppresses an increase in magnetic loss in a high temperature range and has excellent DC bias characteristics. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of an inductor using a magnetic material according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the inductor shown in FIG. [Diagram 3]FIG. 3 is a diagram illustrating a cross section of the magnetic material according to the embodiment. [Figure 4] FIG. 4 is a flowchart showing the manufacturing process of the magnetic material, the powder magnetic core, and the inductor according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing the composition ratio of the Fe—Si—Al based magnetic metal powder contained in the magnetic material. [Figure 6] FIG. 6 is a diagram showing the minimum value in the temperature characteristic of the magnetic loss of the powder magnetic core. [Figure 7] FIG. 7 is a diagram showing the minimum temperature in the temperature characteristics of magnetic loss in the powder magnetic core. [Figure 8] FIG. 8 is a diagram showing values ​​of the initial relative magnetic permeability of the powder magnetic core. [Figure 9] FIG. 9 is a diagram showing the relationship between the relative permeability of the powder magnetic core and a DC magnetic field. [Figure 10] FIG. 10 is a diagram showing the relationship between the oxygen content and the initial relative magnetic permeability of the Fe—Si—Al based magnetic metal powder contained in the magnetic material. [Figure 11] FIG. 11 is a diagram showing the relationship between the particle size distribution and the initial relative magnetic permeability of the Fe—Si—Al based magnetic metal powder contained in the magnetic material. [Figure 12] FIG. 12 is a diagram showing the relationship between the packing rate and the relative magnetic permeability of the Fe—Si—Al based magnetic metal powder in the dust core. [Figure 13] FIG. 13 is a diagram showing the relationship between the heat treatment temperature when the powder magnetic core is heat treated and the magnetic properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0014] Note that the embodiments described below each show a specific example of the present disclosure. The numerical values, shapes, materials, components, component arrangement positions, connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in an independent claim showing a top concept are described as optional components.

[0015] (Embodiment) [Magnetic materials and inductor configuration] The configurations of the magnetic material and inductor according to the embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0016] Fig. 1 is a perspective view of an inductor 1 using a magnetic material according to an embodiment. Fig. 2 is an exploded perspective view of the inductor 1 shown in Fig. 1. Fig. 3 is a schematic diagram showing a cross section of the magnetic material.

[0017] As shown in FIGS. 1 and 2, the inductor 1 includes a magnetic core 10 and a coil portion 20 provided inside the magnetic core 10.

[0018] The coil portion 20 is composed of a coil conductor 21 and two coil supports 22. A part of the coil portion 20 is provided inside the magnetic core 10, and the remaining part protrudes to the outside of the magnetic core 10. The magnetic core 10 is a dust core composed of two powder cores 11. The powder cores 11 are formed by pressure-molding a magnetic material into a predetermined shape. The magnetic core 10 is assembled to the coil conductor 21 via the coil supports 22.

[0019] The magnetic material constituting the dust core 11 is a material containing Fe—Si—Al based metal magnetic powder 12 (see FIG. 3). Hereinafter, the Fe—Si—Al based metal magnetic powder 12 may be referred to as metal magnetic powder 12.

[0020] The dust core 11 is formed by pressure molding a plurality of metal magnetic powders 12 and insulating material 13. As shown in Fig. 3, insulating material 13 is provided between each of the metal magnetic powders 12, and each of the metal magnetic powders 12 is insulated from each other.

[0021] The metal magnetic powder 12 of the present embodiment is a magnetic powder containing Fe as a main component. The composition ratio of the metal magnetic powder 12 is as follows, where the Si content is A% by weight and the Al content is B% by weight: (a) 7.2% by weight≦A≦8.1% by weight, (b) 6.0% by weight≦B≦7.5% by weight, (c)2A+B≦22.7% by weight, The remaining weight percent is made up of Fe. Metal magnetic powder 12 may contain unavoidable impurities other than Fe, Si, and Al.

[0022] By having the composition ratio of the metal magnetic powder 12 satisfy the above relationship (a) to (c), it is possible to provide a magnetic material, etc., that suppresses an increase in magnetic loss in a high temperature range and has excellent DC bias characteristics. The reason for setting the composition ratio of the metal magnetic powder 12 in the above range will be explained later.

[0023] [Methods of manufacturing magnetic materials, powder magnetic cores, and inductors] Methods for producing the magnetic material, the powder magnetic core, and the inductor described above will now be described.

[0024] FIG. 4 is a flowchart showing the manufacturing process of the magnetic material, the powder magnetic core 11, and the inductor 1 according to the embodiment.

[0025] The manufacturing process of the inductor 1 is made up of a granulated powder manufacturing process S10 for producing a magnetic material, a core manufacturing process S20 for forming a powder core 11, and a coil assembly process S30 for assembling the powder core 11, a coil conductor 21, and a coil support 22 to manufacture the inductor 1. Each process will be described below.

[0026] In the granulated powder manufacturing process S10, first, raw materials for producing the magnetic material are prepared (step S11). The raw materials for producing the magnetic material are metal magnetic powder 12, an insulating resin material, a binding resin material, and an organic solvent. The particle size distribution of the metal magnetic powder 12 is, for example, (D90-D10) / D50≧1.0. The metal magnetic powder 12 contains a small amount of oxygen. The oxygen content of the metal magnetic powder 12 is, for example, 500 ppm or less. The particle size distribution and oxygen content will be described later.

[0027] Next, the metal magnetic powder 12, the insulating resin material, the binding resin material, and the organic solvent are kneaded and dispersed (step S12). This produces a mixture containing the metal magnetic powder 12, the insulating resin material, the binding resin material, and the organic solvent. The kneading and dispersion are performed, for example, by placing the weighed metal magnetic powder 12, the insulating resin material, the binding resin material, and the organic solvent in a container and mixing and dispersing them in a rotating ball mill.

[0028] After the metal magnetic powder 12, the insulating resin material, the binding resin material, and the organic solvent are mixed and dispersed, they are granulated and dried (step S13). Specifically, the mixture produced in step S12 is heat-treated at a predetermined temperature. This heat treatment removes the organic solvent from the mixture, and a granulated powder composed of the metal magnetic powder 12, the insulating resin material, and the binding resin material is obtained.

[0029] Next, the granulated powder granulated in step S13 is further pulverized to form a powder, and the granulated powder is classified into predetermined particle sizes (step S14). As a result, a magnetic material made of the granulated powder is obtained.

[0030] Next, the core manufacturing step S20 will be described. In the core manufacturing step S20, first, a magnetic material is pressure-molded into a predetermined shape (step S21). Specifically, the magnetic material is placed in a molding die and compressed to produce the powder magnetic core 11. At this time, for example, 8 ton / cm 2 More than 12ton / cm 2The uniaxial compaction is performed at the following compaction pressure: The filling rate of the metal magnetic powder 12 in the dust core 11 is, for example, 81% or more and 85% or less.

[0031] Next, the powder core 11 is heated at a temperature of 200° C. to 450° C. in an atmosphere of an inert gas such as N2 gas or in the air, and degreased (step S22).

[0032] Next, the degreased powder core 11 is annealed (heat treated) (step S23). The annealing is performed at a predetermined oxygen partial pressure, for example, at a temperature range of 650° C. to 800° C. For example, an atmosphere-controlled electric furnace is used for the annealing.

[0033] Next, the annealed powder core 11 is impregnated with a resin material (step S24). Through the above steps, the powder core 11 composed of the metal magnetic powder 12 and the insulating material 13 is formed.

[0034] Next, the coil assembly process S30 will be described. In the coil assembly process S30, the magnetic core 10 is assembled to the coil portion 20 (step S31). Then, the assembled magnetic core 10 and the coil portion 20 are molded with a resin material (step S32). By this assembly process S30, the inductor 1 is completed.

[0035] [Composition ratio of metal magnetic powder] The composition ratio of the metal magnetic powder 12 shown above will be explained with reference to FIGS.

[0036] Fig. 5 is a diagram showing the composition ratio of Fe-Si-Al-based metal magnetic powder 12 contained in a magnetic material. Fig. 5(a) shows the composition ratio, magnetic loss, relative permeability, etc. of the metal magnetic powder 12, and also shows samples No. 1 to No. 18 in which the composition ratio of the metal magnetic powder 12 is changed. Fig. 5(b) shows a graph of the range of the composition ratio of the metal magnetic powder 12. The numbers in Fig. 5(b) indicate the sample numbers.

[0037] In addition to Fe, which is the main component, the metal magnetic powder 12 also contains Si and Al. The weight percentages of Si and Al are determined to be within desirable ranges that meet the conditions for suppressing an increase in magnetic loss in the high temperature range and the conditions for obtaining excellent DC bias characteristics.

[0038] First, the conditions for suppressing an increase in magnetic loss in the high temperature range will be described.

[0039] Fig. 6 is a diagram showing the minimum value in the temperature characteristic of the magnetic loss of the powder magnetic core, and Fig. 7 is a diagram showing the minimum temperature in the temperature characteristic of the magnetic loss of the powder magnetic core.

[0040] As shown in Figures 6 and 7, the magnetic loss of the powder magnetic core changes with temperature. For example, if the magnetic loss at a given temperature is too large, the powder magnetic core made of a magnetic material may generate abnormal heat, causing a malfunction in the inductor. Therefore, in this embodiment, the composition ratio of the metal magnetic powder 12 is determined so that the magnetic loss is equal to or less than a given threshold value at a given temperature when the inductor is operated.

[0041] Figure 6 shows the magnetic loss threshold of 600 kW / m 3 FIG. 7 shows an example where the predetermined temperature is set to 100°C (where the frequency is 100 kHz and the magnetic flux density is 100 mT). FIG. 7 also shows an example where the predetermined temperature is set to 100°C. The predetermined temperature of 100°C is a value set based on the heat resistance temperature of the inductor. The predetermined threshold value of the magnetic loss is 600 kW / m 3is a value set to maintain the inductor at or below its heat-resistant temperature during operation. For example, sample A in FIG. 6 has a minimum magnetic loss value greater than a predetermined threshold, so the powder core is prone to abnormal heating. In contrast, sample B in FIG. 6 has a minimum magnetic loss value less than a predetermined threshold, so the powder core is less prone to abnormal heating. For example, sample C in FIG. 7 has a minimum magnetic loss at a temperature less than 100°C, so it does not meet the heat-resistant temperature limit of the inductor. In contrast, sample D in FIG. 7 has a minimum magnetic loss at a temperature greater than 100°C, so it meets the heat-resistant temperature limit of the inductor.

[0042] In this manner, in the present embodiment, the condition for suppressing the increase in magnetic loss in the high temperature region is "minimum magnetic loss value ≦ 600 kW / m 3 " and "The temperature at which the magnetic loss is minimum ≧100° C." In the following, it will be explained whether or not Samples No. 1 to No. 18 shown in FIG. 5 satisfy the above conditions.

[0043] As shown in FIG. 5, samples No. 1 to No. 5 and No. 10 to No. 18 have a minimum magnetic loss value of ≦600 kW / m 3 " However, samples No. 6 to No. 9 meet the condition "minimum magnetic loss value ≦ 600 kW / m 3 " Moreover, samples No. 1 to No. 13 satisfy the condition "temperature at which magnetic loss is minimum ≧ 100°C", but samples No. 14 to No. 18 do not satisfy the condition "temperature at which magnetic loss is minimum ≧ 100°C".

[0044] Next, conditions for obtaining excellent DC bias characteristics will be described.

[0045] Fig. 8 is a diagram showing the initial relative permeability of a powder magnetic core. Fig. 9 is a diagram showing the relationship between the relative permeability of a powder magnetic core and a DC magnetic field. Note that the initial relative permeability is the relative permeability when the magnetic field is near 0 (A / m).

[0046] As shown in Figs. 8 and 9, the relative permeability of the powder magnetic core changes with a DC magnetic field. For example, if the decrease in relative permeability when a DC magnetic field is applied is too large, that is, if the DC superposition characteristics are poor, magnetic saturation is likely to occur, making it difficult to function as an inductor. Also, if the initial relative permeability of the powder magnetic core is too low, the inductance value will be low and the basic performance as an inductor will not be achieved. Therefore, in this embodiment, the composition ratio of the metal magnetic powder 12 is determined so that the initial relative permeability is a predetermined threshold value or more, and so that the DC magnetic field when the initial relative permeability is halved (half-life value) is a predetermined threshold value or more.

[0047] FIG. 8 shows an example in which the predetermined threshold value of the initial relative permeability is set to 80 (however, the frequency is 100 kHz). The predetermined threshold value of 80 is a value set based on the heat resistance temperature of the inductor. For example, if the initial relative permeability is low, it is necessary to increase the number of turns of the coil to obtain the required inductance value, which leads to heat generation in the powder magnetic core. Therefore, a predetermined threshold value is set for the initial relative permeability so as not to exceed the heat resistance temperature of the inductor.

[0048] FIG. 9 shows an example where the predetermined threshold value of the DC magnetic field is set to 2.8 kA / m (however, the frequency is 100 kHz). The predetermined threshold value of 2.8 kA / m is also a value set based on the heat resistance temperature of the inductor. For example, if the DC magnetic field (half value) when the initial relative permeability is halved is small, it is necessary to increase the number of turns of the coil to obtain the required inductance value, which leads to heat generation in the powder magnetic core. Therefore, in order to prevent the heat resistance temperature of the inductor from being exceeded, a predetermined threshold value is set for the DC magnetic field (half value) when the initial relative permeability is halved.

[0049] For example, sample E in FIG. 8 has an initial relative permeability smaller than a predetermined threshold, so it may not be able to withstand the heat-resistant temperature of an inductor. In contrast, sample F in FIG. 8 has an initial relative permeability equal to or greater than a predetermined threshold, so it may be able to withstand the heat-resistant temperature of an inductor. For example, sample G in FIG. 9 has a DC magnetic field (half value) smaller than a predetermined threshold, so it may not be able to withstand the heat-resistant temperature of an inductor. In contrast, sample H in FIG. 9 has a DC magnetic field (half value) equal to or greater than a predetermined threshold, so it may be able to withstand the heat-resistant temperature of an inductor.

[0050] In this embodiment, the conditions for obtaining excellent DC bias characteristics are set as "initial relative permeability ≧80" and "DC magnetic field when initial relative permeability is reduced by half ≧2.8 kA / m." In the following, it will be explained whether or not Samples No. 1 to No. 18 shown in FIG. 5 satisfy the above conditions.

[0051] As shown in Fig. 5, all of Samples No. 1 to No. 18 satisfy the condition "initial relative permeability ≧ 80". Also, Samples No. 1 to No. 9 satisfy the condition "DC magnetic field when initial relative permeability is reduced by half ≧ 2.8 kA / m", but Samples No. 10 to No. 15 do not satisfy the condition "DC magnetic field when initial relative permeability is reduced by half ≧ 2.8 kA / m".

[0052] These results indicate that the minimum magnetic loss value is ≦600kW / m 3 Samples No. 1 to No. 5 satisfy all of the following conditions: "Temperature at which magnetic loss is minimum ≧100° C.," "Initial relative permeability ≧80," and "DC magnetic field at which initial relative permeability is reduced by half ≧2.8 kA / m."

[0053] Figure 5(b) shows data plotting the Si weight percentage and Al weight percentage for samples No. 1 to No. 18. The region enclosed by the solid line in the figure is the region that includes the data for samples No. 1 to No. 5, but does not include the data for samples No. 6 to No. 18. The region enclosed by the solid line in the figure is expressed by the following relationship, where the Si content is A weight percentage and the Al content is B weight percentage: (a) 7.2 weight%≦A≦8.1 weight%, (b) 6.0 weight%≦B≦7.5 weight%, (c) 2A+B≦22.7 weight%.

[0054] By ensuring that the composition ratio of the metal magnetic powder 12 satisfies the above relationship (a) to (c), it is possible to provide a magnetic material, etc., that is suppressed from increasing in magnetic loss in the high temperature range and has excellent DC bias characteristics.

[0055] (More desirable example of embodiment) Next, a more preferable example of the embodiment will be described.

[0056] [Oxygen content of metal magnetic powder] FIG. 10 is a diagram showing the relationship between the oxygen content and the initial relative permeability of the Fe—Si—Al based magnetic metal powder 12 contained in the dust core.

[0057] The oxygen contained in the metal magnetic powder 12 is contained, for example, when the metal magnetic powder 12 is produced. As shown in Fig. 10, the lower the oxygen content of the metal magnetic powder 12, the higher the initial relative permeability tends to be. Here, when the predetermined threshold value of the initial relative permeability is set to 80 (see the explanation in Fig. 8), the initial relative permeability becomes equal to or higher than the predetermined threshold value when the oxygen content is 500 ppm or less. Therefore, it is desirable that the oxygen content of the metal magnetic powder 12 is 500 ppm or less.

[0058] In this way, by setting the oxygen content of the metal magnetic powder 12 to 500 ppm or less, it is possible to increase the initial relative permeability of the powder magnetic core formed from the magnetic material, thereby providing a magnetic material capable of increasing the inductance value.

[0059] [Particle size distribution of metal magnetic powder] Fig. 11 is a diagram showing the relationship between the particle size distribution and the initial relative magnetic permeability of the Fe-Si-Al-based metal magnetic powder 12 contained in the magnetic material. Fig. 11(a) shows samples No. 21 to No. 31 in which the particle size distribution of the metal magnetic powder 12 is changed. Fig. 11(b) shows a graph of the relationship between the particle size distribution and the initial relative magnetic permeability. The numbers in Fig. 11(b) indicate the sample numbers.

[0060] The particle size distribution is given by the formula "(D90-D10) / D50". Note that D10, D50, and D90 are the particle sizes at which the cumulative frequency is 10%, 50%, and 90%, respectively. The particle size can be determined, for example, by a laser diffraction particle size distribution measurement method.

[0061] As shown in Fig. 11, the larger the particle size distribution, the higher the initial relative permeability tends to be. Here, when the predetermined threshold value of the initial relative permeability is set to 80 (see the explanation in Fig. 8), the initial relative permeability is equal to or greater than the predetermined threshold value in samples No. 21 to No. 29, but is smaller than the predetermined threshold value in samples No. 30 and 31. Therefore, it is desirable that the particle size distribution of metal magnetic powder 12 is (D90-D10) / D50≧1.0.

[0062] In this way, by making the particle size distribution of the metal magnetic powder 12 such that (D90-D10) / D50≧1.0, it is possible to increase the initial relative permeability of the powder magnetic core formed from the magnetic material, thereby providing a magnetic material capable of increasing the inductance value.

[0063] [Filling rate of metal magnetic powder in dust core] 12 is a diagram showing the relationship between the packing rate and relative magnetic permeability of the Fe-Si-Al based metal magnetic powder 12 in the dust core 11. In this example, the composition ratio of the metal magnetic powder 12 was Fe-7.6 wt % Si-6.6 wt % Al.

[0064] Fig. 12(a) shows samples No. 41 to No. 49 in which the filling rate of the metal magnetic powder 12 was changed. The filling rate was changed by changing the molding pressure when the magnetic material was pressure-molded (step S21). Fig. 12(b) shows a graph of the relationship between the initial relative permeability and the half value, which changes depending on the filling rate. The numbers in Fig. 12(b) indicate the sample numbers.

[0065] As shown in Fig. 12, the higher the filling rate of the metal magnetic powder 12, the higher the initial relative permeability of the powder magnetic core tends to be. Here, when the predetermined threshold value of the initial relative permeability is set to 80 (see the explanation in Fig. 8), the initial relative permeability of samples Nos. 43 to 49 is equal to or greater than the predetermined threshold value, but the initial relative permeability of samples Nos. 41 and 42 is smaller than the predetermined threshold value. In other words, when the filling rate is low, the initial relative permeability decreases.

[0066] Furthermore, when the predetermined threshold value of the DC magnetic field (half-value) at which the initial relative permeability is halved is set to 2.8 kA / m (see the explanation in FIG. 9), the half-value values ​​of samples Nos. 41 to 47 are equal to or greater than the predetermined threshold value, but the half-values ​​of samples Nos. 48 and 49 are smaller than the predetermined threshold value. In other words, if the filling rate is too high, the half-value value becomes small. From these results, it is desirable that the filling rate of metal magnetic powder 12 in dust core 11 is 81% or more and 85% or less.

[0067] In this way, by setting the filling rate of the metal magnetic powder 12 to 81% or more and 85% or less, the initial relative permeability of the powder magnetic core can be increased, and the DC magnetic field when the initial relative permeability is reduced by half (half-value) can be increased. This makes it possible to provide a magnetic material or the like having excellent DC superposition characteristics.

[0068] [Heat treatment temperature for powder magnetic cores] FIG. 13 is a diagram showing the heat treatment temperature when the powder magnetic core 11 is heat treated.

[0069] As shown in Fig. 13, the higher the heat treatment temperature and the higher the filling rate, the higher the initial relative permeability of the powder magnetic core tends to be. Here, when the predetermined threshold value of the initial relative permeability is set to 80 (see the explanation in Fig. 8), the initial relative permeability of samples No. 51 to No. 57 is equal to or higher than the predetermined threshold value.

[0070] In addition, the specified threshold for magnetic loss is set at 600 kW / m 3 When the heat treatment temperature is set at 650° C. (see the explanation in FIG. 6), the magnetic loss is equal to or less than the predetermined threshold in samples No. 52 to No. 55, but is greater than the predetermined threshold in samples No. 51, 56, and 57. The reason why the magnetic loss increases when the heat treatment temperature is low is believed to be that if the heat treatment temperature is too low, the effect of removing distortion decreases and hysteresis loss increases. The reason why the magnetic loss increases when the heat treatment temperature is high is believed to be that if the heat treatment temperature is too high, the insulation between powder particles is destroyed, and eddy current loss, which is one type of magnetic loss, increases. Based on these results, it is desirable for the heat treatment temperature of the powder core 11 to be 650° C. or more and 800° C. or less.

[0071] In this way, by setting the heat treatment temperature of powder core 11 to be 650° C. or more and 800° C. or less, it is possible to increase the initial relative permeability of powder core 11 and also to reduce magnetic loss, thereby making it possible to provide powder core 11 that suppresses an increase in magnetic loss in the high temperature range.

[0072] (summary) The magnetic material of this embodiment is a magnetic material containing Fe-Si-Al metal magnetic powder 12, and when the Si content is A weight % and the Al content is B weight %, the Fe-Si-Al metal magnetic powder 12 has the relationships 7.2 weight %≦A≦8.1 weight %, 6.0 weight %≦B≦7.5 weight %, and 2A+B≦22.7 weight %.

[0073] When the Si and Al contained in the Fe-Si-Al-based metal magnetic powder 12 have the above-mentioned relationship, it is possible to suppress an increase in magnetic loss in the high temperature range and provide a magnetic material having excellent DC bias characteristics.

[0074] The oxygen content of the Fe-Si-Al based magnetic metal powder 12 may be 500 ppm or less.

[0075] In this way, by setting the oxygen content of the Fe-Si-Al-based metal magnetic powder 12 to 500 ppm or less, it is possible to increase the initial relative permeability of the powder magnetic core formed from the magnetic material, thereby providing a magnetic material capable of increasing the inductance value.

[0076] The particle size distribution of the Fe-Si-Al based magnetic metal powder 12 may be (D90-D10) / D50≧1.0.

[0077] In this way, by making the particle size distribution of the metal magnetic powder 12 such that (D90-D10) / D50≧1.0, it is possible to increase the initial relative permeability of the powder magnetic core formed from the magnetic material, thereby providing a magnetic material capable of increasing the inductance value.

[0078] The powder magnetic core 11 according to the present embodiment contains the above-mentioned magnetic material.

[0079] This makes it possible to provide a powder magnetic core 11 that is formed from a magnetic material that suppresses an increase in magnetic loss in a high temperature range and has excellent DC bias characteristics.

[0080] The filling rate of the Fe—Si—Al based magnetic metal powder 12 in the dust core 11 may be 81% or more and 85% or less.

[0081] In this way, by setting the filling rate of the metal magnetic powder 12 to 81% or more and 85% or less, it is possible to increase the initial relative permeability and to increase the DC magnetic field when the initial relative permeability is halved, thereby providing the dust core 11 formed of a magnetic material having excellent DC bias characteristics.

[0082] The inductor 1 according to this embodiment includes a magnetic core 10 formed of a powder magnetic core 11, and a coil portion 20 at least a portion of which is provided inside the magnetic core 10.

[0083] According to this configuration, it is possible to provide an inductor 1 formed of a powder magnetic core 11 that suppresses an increase in magnetic loss in a high temperature range and has excellent DC bias characteristics.

[0084] The method for manufacturing a powder magnetic core according to this embodiment includes a step of compacting the above-mentioned magnetic material to form powder magnetic core 11, and a step of heat treating compacted powder magnetic core 11 at a temperature of 650°C or higher and 800°C or lower.

[0085] In this way, the initial relative permeability can be increased and the magnetic loss can be reduced by setting the heat treatment temperature of powder core 11 to 650° C. or more and 800° C. or less, thereby making it possible to manufacture powder core 11 in which the increase in magnetic loss in the high temperature range is suppressed.

[0086] (Other embodiments, etc.) Although the magnetic materials and the like according to the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments.

[0087] For example, examples of inductors using the above-mentioned magnetic material include inductance components such as high-frequency reactors, inductors, and transformers. In addition, a power supply device including the above-mentioned inductor is also included in the present disclosure.

[0088] Furthermore, the present disclosure is not limited to the embodiment. As long as it does not deviate from the spirit of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiment and forms constructed by combining components in different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0089] The magnetic material of the present disclosure can be used as a material for high-frequency inductors, magnetic cores of transformers, and the like. [Explanation of symbols]

[0090] 1 Inductor 10 Magnetic core 11 Powder magnetic core 12 Metal magnetic powder 13 Insulation materials 20 Coil section 21 Coil conductor 22 Coil support

Claims

1. A magnetic material containing an Fe-Si-Al-based metal magnetic powder, The Fe-Si-Al based magnetic metal powder is When the Si content is A% by weight and the Al content is B% by weight, The relationship is 7.2% by weight≦A<7.6% by weight, and 6.0% by weight≦B≦7.5% by weight. magnetic material.

2. The oxygen content of the Fe-Si-Al based magnetic metal powder is 500 ppm or less. The magnetic material according to claim 1 .

3. The particle size distribution of the Fe-Si-Al based magnetic metal powder is (D90-D10) / D50≧1.

0. The magnetic material according to claim 1 .

4. A powder magnetic core comprising the magnetic material according to any one of claims 1 to 3.

5. The filling rate of the Fe-Si-Al-based metal magnetic powder in the powder magnetic core is 81% or more and 85% or less. The dust core according to claim 4 .

6. A magnetic core constituted by the powder magnetic core according to claim 4 or 5; A coil portion at least a part of which is provided inside the magnetic core; An inductor comprising:

7. A method for producing the powder magnetic core according to claim 4 or 5, A step of compacting the magnetic material according to any one of claims 1 to 3 to form the powder magnetic core; A step of heat treating the compacted powder core at 650° C. or more and 800° C. or less; A method for producing a powder magnetic core comprising the steps of:

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