JP2020023749A - Soft magnetic powder, green compact and magnetic component - Google Patents

Abstract

To provide a soft magnetic powder having excellent soft magnetic properties and high powder resistance.SOLUTION: A soft magnetic powder contains a main component of the compositional formula (FeX1X2)MBPSiCS, X1 is at least one selected from the group consisting of Co and Ni, X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, and rare earth elements, M is at least one selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti and V, with 0≤a≤0.140, 0.020<b≤0.200, 0<c≤0.150, 0≤d≤0.060, 0≤e≤0.030, 0≤f≤0.010, α≥0, β≥0, 0≤α+β≤0.50; an oxygen content in the soft magnetic powder being 300 ppm or more and 3000 ppm or less in mass ratio.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a soft magnetic powder, a green compact, and a magnetic component.

  2. Description of the Related Art In recent years, low power consumption and high efficiency have been demanded for electronic, information, and communication devices. Furthermore, the above-mentioned demands are becoming stronger toward a low-carbon society. Therefore, power supply circuits for electronic, information, and communication devices are also required to reduce energy loss and improve power supply efficiency. The magnetic core of the magnetic element used in the power supply circuit is required to have an improved saturation magnetic flux density and a reduced core loss (core loss).

  Patent Literature 1 discloses a soft magnetic amorphous alloy based on Fe-BM (M = Ti, Zr, Hf, V, Nb, Ta, Mo, W). This soft magnetic amorphous alloy has good soft magnetic properties, such as having a higher saturation magnetic flux density than commercially available Fe amorphous.

Patent No. 3342767

  However, at present, there is a demand for a soft magnetic powder having good soft magnetic properties and high powder resistance.

  An object of the present invention is to provide a soft magnetic powder having excellent soft magnetic properties and a high powder resistance.

In order to achieve the above object, the soft magnetic powder of the present invention comprises:
Composition formula _{(Fe (1- (α + β} )) X1 α X2 β) a soft magnetic powder comprising a main component composed of _{(1- (a + b + c} + d + e + f)) M a B b P c Si d C e S f,
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti and V;
0 ≦ a ≦ 0.140
0.020 <b ≦ 0.200
0 <c ≦ 0.150
0 ≦ d ≦ 0.060
0 ≦ e ≦ 0.030
0 ≦ f ≦ 0.010
α ≧ 0
β ≧ 0
0 ≦ α + β ≦ 0.50
And
The soft magnetic powder has an oxygen content of 300 ppm or more and 3000 ppm or less by mass ratio.

  The soft magnetic powder of the present invention, having the above-described configuration, has excellent soft magnetic properties and can further increase the powder resistance. And, by using the soft magnetic powder of the present invention, it becomes easy to produce a green compact having high resistivity.

  The soft magnetic powder of the present invention may be amorphous.

  The soft magnetic powder of the present invention may be composed of amorphous and microcrystals, and a nanoheterostructure in which the microcrystals exist in the amorphous phase may be observed.

  The soft magnetic powder of the present invention may have an average particle diameter of the microcrystal of 0.3 to 10 nm.

  In the soft magnetic powder of the present invention, a structure composed of Fe-based nanocrystals may be observed.

  In the soft magnetic powder of the present invention, the Fe-based nanocrystal may have an average particle size of 3 nm to 50 nm.

In the soft magnetic powder of the present invention, a Fe composition network phase may be observed in which a Fe content ratio is connected to a region higher than the Fe content ratio contained in the entire soft magnetic powder by a three-dimensional atom probe,
The Fe composition network phase may have the maximum point of the Fe content ratio at which the Fe content ratio is locally higher than the surroundings is 400,000 / μm ³ or more,
Among all the maximum points of the Fe content ratio, the ratio of the maximum point of the Fe content ratio having a coordination number of 1 to 5 may be 80% to 100%.

  In the soft magnetic powder of the present invention, a volume ratio of the Fe composition network phase in the entire soft magnetic powder may be 25 vol% or more and 50 vol% or less.

The soft magnetic powder of the present invention may have a volume resistivity of 0.5 kΩ · cm or more and 500 kΩ · cm or less when compacted at a pressure of 0.1 t / cm ² .

  The green compact of the present invention includes the above soft magnetic powder.

  The magnetic component of the present invention has the above compact.

It is a schematic diagram of the process of searching for a maximum point. It is a schematic diagram of the state where the line segment which connects all the maximum points was produced | generated. It is a schematic diagram of the state divided into the area | region where Fe content rate exceeds an average value, and the area | region below an average value. FIG. 7 is a schematic diagram of a state in which a line segment passing through a region where the Fe content ratio is equal to or less than an average value is deleted. FIG. 9 is a schematic diagram of a state in which the longest line segment among the line segments forming a triangle is deleted when there is no portion where the Fe content ratio is equal to or less than the average value inside the triangle.

  Hereinafter, embodiments of the present invention will be described.

Soft magnetic powder of the present embodiment includes a main component having the composition formula _{(Fe (1- (α + β} )) X1 α X2 β) (1- (a + b + c + d + e + f)) M a B b P c Si d C e S f Soft magnetic powder,
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti and V;
0 ≦ a ≦ 0.140
0.020 <b ≦ 0.200
0 <c ≦ 0.150
0 ≦ d ≦ 0.060
0 ≦ e ≦ 0.030
0 ≦ f ≦ 0.010
α ≧ 0
β ≧ 0
0 ≦ α + β ≦ 0.50
And
The soft magnetic powder has an oxygen content of 300 ppm or more and 3000 ppm or less by mass ratio.

  The soft magnetic powder according to the present embodiment has excellent soft magnetic properties. That is, the coercive force Hc is low and the saturation magnetization s is high. Furthermore, the powder resistance is high. The green compact including the soft magnetic powder according to the present embodiment can easily improve the volume resistivity. Specifically, a green compact having a volume resistivity of 0.5 kΩ · cm to 500 kΩ · cm is easily formed.

  Hereinafter, each component of the soft magnetic powder according to the present embodiment will be described in detail.

  M is at least one selected from Nb, Hf, Zr, Ta, Mo, W, Ti and V.

  The content (a) of M satisfies 0 ≦ a ≦ 0.140. That is, M may not be contained. The content (a) of M is preferably 0.040 ≦ a ≦ 0.140, and more preferably 0.040 ≦ a ≦ 0.100. When a is large, the saturation magnetization σs tends to decrease. Further, the case where M is not contained is preferable in that the saturation magnetic flux density becomes higher than the case where M is contained.

  The content (b) of B satisfies 0.020 <b ≦ 0.200. 0.025 ≦ b ≦ 0.200. Further, it is preferable that 0.060 ≦ b ≦ 0.200, and it is more preferable that 0.060 ≦ b ≦ 0.150. If b is small, a crystalline phase composed of crystals having a particle size larger than 30 nm is likely to be formed in the soft magnetic powder before the heat treatment. If a crystalline phase is formed, a suitable structure cannot be obtained by the heat treatment. Then, the coercive force tends to increase. When b is large, the saturation magnetization tends to decrease.

  The P content (c) satisfies 0 <c ≦ 0.150. It may be 0.001 ≦ c ≦ 0.150. Further, it is preferable that 0.010 ≦ c ≦ 0.150, and it is more preferable that 0.050 ≦ c ≦ 0.080. It is considered that, by containing P, the soft magnetic alloy according to the present embodiment combines P and oxygen (O) to increase the powder resistance. When c = 0, that is, when P is not included, the coercive force tends to increase. When c is large, the saturation magnetization tends to decrease.

  The content (d) of Si satisfies 0 ≦ d ≦ 0.060. That is, Si may not be contained. Further, it is preferable that 0 ≦ d ≦ 0.030. When d is large, the coercive force tends to increase, and the saturation magnetization tends to decrease.

  The content (e) of C satisfies 0 ≦ e ≦ 0.030. That is, C may not be contained. Further, it is preferable that 0 ≦ e ≦ 0.010. If e is large, the coercive force will increase.

  The S content (f) satisfies 0 ≦ f ≦ 0.010. That is, S may not be contained. Further, it is preferable that 0 ≦ f ≦ 0.005. If f is large, the coercive force will increase.

  Further, when S is not contained (when f = 0), the resistivity is more likely to decrease as the C content increases. However, by simultaneously containing C and S, it is easy to suppress a decrease in resistivity due to the inclusion of C.

The soft magnetic powder according to the present embodiment has an oxygen content of 300 ppm or more and 3000 ppm or less by mass ratio. Further, the content is preferably 800 ppm or more and 2000 ppm or less. By controlling the oxygen content within the above range, the saturation magnetization can be increased and the powder resistance can be further increased. Further, the volume resistivity of the green compact including the soft magnetic powder according to the present embodiment can be easily improved. Specifically, when the compact is pressed at a pressure of 0.1 t / cm ² , the volume resistivity is 0.5 kΩ · cm. It is possible to obtain a green compact of 500 kΩcm or less. By using a soft magnetic powder having a high powder resistance, the particles of the soft magnetic powder are sufficiently insulated from each other, so that a green compact or the like having high soft magnetic characteristics and low loss at the same time can be obtained. If the oxygen content is too low, the powder resistance tends to decrease. If the oxygen content is too high, the powder resistance tends to decrease, and the saturation magnetization tends to decrease.

  Further, in the soft magnetic powder of the present embodiment, a part of Fe may be replaced with X1 and / or X2.

  X1 is at least one selected from the group consisting of Co and Ni. Regarding the content of X1, α = 0 may be satisfied. That is, X1 may not be contained. Further, the number of atoms of X1 is preferably 40 at% or less, with the total number of atoms of the composition being 100 at%. That is, it is preferable to satisfy 0 ≦ α {1- (a + b + c + d + e + f)} ≦ 0.400.

  X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N and rare earth elements. Regarding the content of X2, β = 0 may be satisfied. That is, X2 may not be contained. Further, the number of atoms of X2 is preferably 3.0 at% or less, where the total number of atoms of the composition is 100 at%. That is, it is preferable to satisfy 0 ≦ β {1- (a + b + c + d + e + f)} ≦ 0.030.

  The range of the substitution amount for substituting Fe with X1 and / or X2 is not more than half of Fe on the atomic number basis. That is, 0 ≦ α + β ≦ 0.500. If α + β> 0.500, it becomes difficult to obtain the soft magnetic powder of the present embodiment by heat treatment.

  The content of (Fe + X1 + X2) (1- (a + b + c + d + e + f)) is arbitrary, but preferably 0.690 ≦ (1- (a + b + c + d + e + f)) ≦ 0.900. By setting (1− (a + b + c + d + e + f)) in the above range, a crystal phase composed of a crystal having a particle size larger than 30 nm is less likely to be generated during the production of the soft magnetic powder of the present embodiment.

  Note that the soft magnetic powder according to the present embodiment may include elements other than the above as inevitable impurities. For example, it may contain 0.1 mass% or less with respect to 100 mass% of the soft magnetic powder.

  Further, the soft magnetic powder according to the present embodiment may include an amorphous material, and may have a nanoheterostructure in which microcrystals exist in the amorphous material. The inclusion of an amorphous material, the inclusion of a microcrystal, and the presence of a nanoheterostructure can be achieved by a method using X-ray structural diffraction, a method for confirming the presence or absence of a lattice by high-resolution image analysis using a transmission electron microscope, It can be observed by a method based on an electron diffraction pattern by a scanning electron microscope. The average diameter of the microcrystals is preferably 0.2 nm or more and 10 nm or less.

  In the soft magnetic powder according to the present embodiment, it is preferable that a structure composed of Fe-based nanocrystals is observed by X-ray structural diffraction.

  The Fe-based nanocrystal is a crystal having a nano-order particle size and a Fe crystal structure of bcc (body-centered cubic lattice structure). In the present embodiment, the average particle diameter of the Fe-based nanocrystal is preferably 3 nm or more and 50 nm or less. Soft magnetic powder having a structure composed of such Fe-based nanocrystals tends to have low coercive force Hc and high saturation magnetization σs. In addition, when Fe-based nanocrystals are observed by X-ray structural diffraction, it is normal that no amorphous state is observed. However, an amorphous state may be observed.

  Further, the soft magnetic powder according to the present embodiment preferably has an Fe composition network phase. Hereinafter, the Fe composition network phase will be described.

  The Fe composition network phase is a phase having a higher Fe content than the average composition of the soft magnetic powder. When the Fe concentration distribution of the soft magnetic powder according to the present embodiment is observed using a three-dimensional atom probe (hereinafter sometimes referred to as 3DAP), a state in which a portion having a high Fe content is distributed in a network is observed. it can.

  The aspect of the Fe composition network phase can be quantified by measuring the number of maximum points and the coordination number of the maximum points of the Fe composition network phase.

  The maximum point of the Fe composition network phase is a point where the Fe content ratio locally becomes higher than the surroundings. Also, the coordination number of the maximum point is the number of other maximum points where one maximum point is connected through the Fe composition network phase.

  Hereinafter, the analysis procedure of the Fe composition network phase in the present embodiment will be described with reference to the drawings, and the local maximum point, the coordination number of the local maximum point, and a method for calculating them will be described.

  First, a cube having a side length of 40 nm is set as a measurement range, and the cube is divided into cubic grids each having a side length of 1 nm. That is, 40 × 40 × 40 = 64000 grids exist in one measurement range.

  Next, the Fe content ratio contained in each grid is evaluated. Then, an average value (hereinafter, sometimes referred to as a threshold) of the Fe content ratio in all grids is calculated. The average value of the Fe content ratio is substantially equal to the value calculated from the average composition of the soft magnetic powder.

  Next, a grid having an Fe content ratio exceeding the threshold value and having a higher Fe content ratio than all adjacent grids is defined as a maximum point. FIG. 1 shows a model showing a process of searching for a local maximum point. The number described inside each grid 10 represents the Fe content ratio included in each grid. A grid having an Fe content ratio equal to or higher than the Fe content ratio of all adjacent grids 10b is defined as a maximum point 10a.

  Also, in FIG. 1, eight adjacent grids 10b are described for one local maximum point 10a. There exists one by one. That is, there are 26 adjacent grids 10b for one maximum point 10a.

  Regarding the grid 10 located at the end of the measurement range, it is considered that a grid having an Fe content ratio of 0 exists outside the measurement range.

  Next, as shown in FIG. 2, a line segment connecting all the maximum points 10a included in the measurement range is generated. When connecting the line segments, the centers of the grids are connected. In FIGS. 2 to 5, the maximum point 10a is indicated by a circle for convenience of explanation. The number described inside the circle is the Fe content ratio.

  Next, as shown in FIG. 3, a region (Fe composition network phase) 20a having an Fe content ratio higher than the threshold value and a region 20b having an Fe content ratio less than the threshold value are divided. Then, as shown in FIG. 4, the line segment passing through the area 20b is deleted.

  Next, as shown in FIG. 5, when the line segment is a portion forming a triangle and there is no region 20b inside the triangle, the longest line among the three line segments forming the triangle is used. Delete one minute. Lastly, when the local maximum points are on the adjacent grid, the line segment connecting the local maximum points is deleted.

  Then, the number of line segments extending from each local maximum point 10a is defined as the coordination number of each local maximum point 10a. For example, in the case of FIG. 5, the maximum point 10a1 having an Fe content ratio of 50 has a coordination number of 4, and the maximum point 10a2 having an Fe content ratio of 41 has a coordination number of 2.

  Further, when the grit present on the outermost surface in the measurement range of 40 nm × 40 nm × 40 nm indicates a local maximum point, the local maximum point is excluded from the calculation of the ratio of the local maximum point whose coordination number is within a specific range described later. I do.

  It is assumed that the Fe composition network phase also includes a local maximum point having a coordination number of 0 and a region having a Fe content higher than a threshold value present around the local maximum point having a coordination number of 0.

  By performing the measurement described above several times in different measurement ranges, the accuracy of the calculated result can be made sufficiently high. Preferably, the measurement is performed three or more times in different measurement ranges.

The Fe composition network phase of the soft magnetic powder according to the present embodiment has a maximum of 400,000 μm / μm ³ or more at the maximum of the Fe content where the Fe content is locally higher than the surroundings. The percentage of the maximum points where the coordination number is 1 or more and 5 or less in the entire maximum points is 80% or more and 100% or less. The denominator of the number of the maximum points is the volume of the entire measurement range, and is the sum of the volume of the region 20a having the Fe content higher than the threshold and the volume of the region 20b having the Fe content lower than the threshold.

  The soft magnetic powder according to the present embodiment has excellent soft magnetic properties by having the Fe composition network phase in which the number of local maximum points and the ratio of local maximum points where the coordination number is 1 or more and 5 or less are within the above ranges. Soft magnetic powder. Specifically, the soft magnetic powder has a low coercive force and a high saturation magnetization.

  Preferably, the ratio of the maximum point where the coordination number occupies 2 or more and 4 or less in the entire maximum point of the Fe content ratio is 70% or more and 90% or less.

  Further, the volume ratio of the Fe composition network phase in the entire soft magnetic powder (the Fe content higher than the threshold in the total of the region 20a having the Fe content higher than the threshold and the region 20b having the Fe content lower than the threshold). The volume ratio of the region 20a) is preferably 25 vol% or more and 50 vol% or less, and more preferably 30 vol% or more and 40 vol% or less.

  Hereinafter, a method for producing the soft magnetic powder according to the present embodiment will be described.

  As a method for obtaining the soft magnetic powder of the present embodiment, for example, there is a method by a water atomizing method or a gas atomizing method. Hereinafter, the gas atomizing method will be described.

  In the gas atomizing method, first, a pure metal of each metal element contained in the finally obtained soft magnetic powder is prepared and weighed so as to have the same composition as the finally obtained soft magnetic powder. Then, a pure metal of each metal element is dissolved and mixed to prepare a mother alloy. The method of melting the pure metal is not particularly limited. For example, there is a method in which the metal is evacuated in a chamber and then melted by high-frequency heating. The mother alloy and the finally obtained soft magnetic powder usually have the same composition except for the oxygen content.

  Next, the produced mother alloy is heated and melted to obtain a molten metal (molten metal). The temperature of the molten metal is arbitrary, but may be, for example, 1200 to 1500 ° C. Thereafter, the molten alloy is sprayed in a chamber to produce a soft magnetic powder. The lower the temperature of the molten metal, the smaller the particle size of microcrystals described later tends to be, and the more difficult it is to generate microcrystals.

  At this time, by setting the gas injection temperature to 50 to 200 ° C. and the vapor pressure in the chamber to 4 hPa or less, the soft magnetic powder can easily have a nanoheterostructure. The nanoheterostructure is a structure in which microcrystals exist in an amorphous state. In addition, the nanoheterostructure does not include a crystal having a particle size larger than 30 nm. The presence or absence of crystals having a particle size larger than 30 nm can be confirmed by, for example, ordinary X-ray diffraction measurement.

  By making the soft magnetic powder have a nanoheterostructure at this point, the soft magnetic powder can be easily made into a structure made of Fe-based nanocrystals by a heat treatment described later. Further, the structure having the above-described Fe composition network phase is easily obtained. Preferably, the microcrystal has an average particle size of 0.3 to 10 nm. The presence or absence and the average particle size of the microcrystals can be changed, for example, by controlling the temperature of the molten metal.

  However, when the finally obtained soft magnetic powder may contain an amorphous material, the soft magnetic powder before the heat treatment does not have to have a nanohetero structure, and may have a structure containing only an amorphous material. When the finally obtained soft magnetic powder has a nanoheterostructure, the soft magnetic powder before heat treatment may have a structure containing only amorphous, or the soft magnetic powder before heat treatment may have a nanoheterostructure.

The method of observing the presence or absence of the above-mentioned microcrystals and the average particle size is not particularly limited.For example, using a transmission electron microscope, a selected area diffraction image, a nanobeam diffraction image, a bright field image, or a high-resolution image is obtained. It can be confirmed by obtaining. When a selected area diffraction image or a nanobeam diffraction image is used, ring-shaped diffraction is formed when the diffraction pattern is amorphous, whereas diffraction spots due to the crystal structure are formed when the diffraction pattern is not amorphous. It is formed. When a bright-field image or a high-resolution image is used, the presence or absence of microcrystals and the average particle diameter can be observed by visually observing at a magnification of 1.00 × 10 ^{5 to} 3.00 × 10 ⁵ times.

  By performing a heat treatment after preparing a soft magnetic powder having a nanoheterostructure by a gas atomizing method, the soft magnetic powder can be easily made to have a suitable structure. Further, the structure having the above-described Fe composition network phase is easily obtained.

  Heat treatment conditions are optional. Preferred heat treatment conditions vary depending on the composition of the soft magnetic powder. In the case where the finally obtained soft magnetic powder has a structure composed of Fe-based nanocrystals and a structure having an Fe composition network phase, the preferable heat treatment temperature is generally about 450 to 650 ° C., and the preferable heat treatment time is generally about 0.5 to 10 hours. However, depending on the composition, a preferable heat treatment temperature and heat treatment time may exist outside the above range.

  When the finally obtained soft magnetic powder has a structure containing only an amorphous material or a nanohetero structure, the heat treatment temperature is set lower than the above temperature, or the soft magnetic powder before the heat treatment is made only of the amorphous material. Is preferable. When reducing the heat treatment temperature, specifically, it is preferable to set the temperature to approximately 300 to 350 ° C.

  The atmosphere at the time of the heat treatment is arbitrary. For example, it is preferable to use an inert atmosphere such as Ar gas. Further, by controlling the oxygen partial pressure in the atmosphere during the heat treatment, the oxygen content in the finally obtained soft magnetic powder can be controlled to a mass ratio of 300 ppm or more and 3000 ppm or less. The oxygen content of the soft magnetic powder before the heat treatment is about 150 ppm, which is outside the above range.

  The method for controlling the oxygen content in the finally obtained soft magnetic powder is arbitrary. In addition to the method of controlling the oxygen partial pressure in the atmosphere at the time of the heat treatment, for example, a method of controlling by changing the oxygen partial pressure in the atmosphere at the time of manufacturing the mother alloy may be used.

  There is no particular limitation on the atmosphere during the heat treatment. It may be performed in an active atmosphere such as the air, or may be performed in an inert atmosphere such as Ar gas.

  Further, there is no particular limitation on the method of calculating the average particle size of the microcrystals or Fe-based nanocrystals contained in the soft magnetic powder obtained by the heat treatment. For example, it can be calculated by observing using a transmission electron microscope. In addition, there is no particular limitation on a method for confirming that the crystal structure of the Fe-based nanocrystal is bcc (body-centered cubic lattice structure). For example, it can be confirmed using X-ray diffraction measurement.

The powder resistance of the soft magnetic powder according to the present embodiment can be evaluated by the volume resistivity of the green compact formed at 0.1 t / cm ² . 0.1 t / cm ² is a low pressure as a molding pressure. That is, the change of the shape and the like of the soft magnetic powder before and after the molding is very small. On the other hand, if the molding pressure is still lower, the density of the green compact may be too low to measure the volume resistivity of the green compact correctly. Therefore, the powder resistance of the soft magnetic powder can be evaluated by evaluating the volume resistivity of the green compact formed from the soft magnetic powder at 0.1 t / cm ² . By controlling the oxygen content of the soft magnetic powder to 300 ppm or more and 3000 ppm or less, it becomes easy to obtain a soft magnetic powder having powder resistance such that the volume resistivity of the green compact becomes 0.5 kΩ · cm or more and 500 kΩ · cm or less. .

  After the soft magnetic powder according to the present embodiment is appropriately mixed with a binder and then compacted using a mold, a compact having high volume resistivity can be obtained. That is, when a soft magnetic powder having a high powder resistance is used, the compacting pressure during compacting is arbitrary, but a compact having a high volume resistivity can be obtained even if the filling rate increases. The type and content of the binder are arbitrary, and the volume resistivity of the green compact changes depending on the type and content of the binder. Furthermore, before mixing with the binder, the surface resistivity of the soft magnetic powder is subjected to an oxidation treatment, an insulating coating, or the like, so that the volume resistivity of the green compact can be further increased.

  Furthermore, by heat-treating the green compact after molding as a strain-relieving heat treatment, the coercive force can be reduced and the core loss can be reduced.

  Moreover, an inductance component can be obtained by winding the green compact. There is no particular limitation on the method of winding and the method of manufacturing the inductance component. For example, there is a method in which a winding is wound at least one or more turns around the green compact manufactured by the above method.

  Furthermore, by performing pressure molding and integrating in a state where the winding coil is contained in the soft magnetic powder according to the present embodiment, an inductance component having the winding coil incorporated in the green compact according to the present embodiment is obtained. It is also possible to manufacture.

  Here, when an inductance component is manufactured using soft magnetic powder, it is preferable to use a soft magnetic powder having a maximum particle size of 45 μm or less as a sieve diameter and a central particle size (D50) of 30 μm or less for excellent Q characteristics. It is preferable to obtain In order to make the maximum particle diameter 45 μm or less in sieve diameter, a sieve having an opening of 45 μm may be used, and only the soft magnetic powder passing through the sieve may be used.

  The Q value in the high frequency region tends to decrease as the soft magnetic powder having the largest particle size is used. Particularly, when the soft magnetic powder having the maximum particle size exceeding 45 μm in the sieve diameter is used, the Q value in the high frequency region is used. May be greatly reduced. However, when the Q value in the high frequency region is not emphasized, a soft magnetic powder having a large variation can be used. Since a soft magnetic powder having a large variation can be manufactured at a relatively low cost, the cost can be reduced when a soft magnetic powder having a large variation is used.

  The use of the green compact according to the present embodiment is arbitrary. It can be used for a magnetic component, for example, a magnetic core, an inductance component, a transformer, a motor, and the like.

  The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

  Hereinafter, the present invention will be specifically described based on examples.

(Experimental example 1)
The raw material metals were weighed so as to have the alloy compositions of the respective examples and comparative examples shown in the following table, and were melted by high-frequency heating to prepare mother alloys. The composition of Sample No. 1 (Comparative Example) is a composition of a generally well-known amorphous alloy.

  Thereafter, the produced mother alloy was pulverized by an atomizing method to obtain a soft magnetic powder. At this time, the temperature of the molten metal flowing down from the crucible was 1250 ° C., the flow rate was 1 kg / min, the inner diameter of the crucible flow port was 1 mm, and the gas jet flux was 900 m / s. Thereafter, classification was performed by a classifier to obtain a soft magnetic powder having an average particle size D50 of 15 μm or more and 30 μm or less.

  X-ray diffraction measurement was performed on the obtained soft magnetic powder, and the presence or absence of crystals having a particle size larger than 30 nm was confirmed. When no crystal having a particle size larger than 30 nm was present, an amorphous phase was observed, and when a crystal having a particle size larger than 30 nm was present, it was determined to be composed of a crystal phase. In all Examples except for Sample No. 181 described below, a nanoheterostructure in which microcrystals having an average particle size of 0.1 nm or more and 15 nm or less exist in the amorphous state was observed.

  Thereafter, the soft magnetic powder of each sample was heat-treated at 600 ° C. for 1 hour. The heat treatment was performed in a nitrogen atmosphere. The oxygen content of the soft magnetic powder after the heat treatment was controlled by controlling the oxygen concentration in the nitrogen atmosphere at the time of the heat treatment within the range of 10 ppm to 10,000 ppm. For each soft magnetic powder after the heat treatment, the saturation magnetization s and the coercive force Hc were measured. The saturation magnetization s was measured using a vibration sample magnetometer (VSM) at a magnetic field of 1000 kA / m. The coercive force Hc was measured at a magnetic field of 5 kA / m using a DC BH tracer.

Thereafter, each soft magnetic powder after the heat treatment was pressed at a pressure of 0.1 t / cm ² , and the (volume) resistivity ρ was measured using a powder resistance device.

Saturation magnetization σs in this example was as good or 150A ^· m 2 / kg. The coercive force Hc was determined to be 4.0 Oe or less. The resistivity ρ was 0.5 kΩ · cm or more and 500 kΩ · cm or less, and the resistivity ρ was 3 kΩ · cm or more and 500 kΩ · cm or less. In the table below, ◎ indicates that the resistivity ρ was 3 kΩ · cm or more, ○ indicates that the resistivity was 0.5 kΩ · cm or more and less than 3 kΩ · cm, and x indicates that the resistivity ρ was less than 0.5 kΩ · cm or more than 500 kΩ · cm. Note that there was no sample having a resistivity ρ exceeding 500 kΩ · cm.

  In Examples of Experimental Example 1 shown below, unless otherwise specified, all of the soft magnetic powders after the heat treatment had Fe-based nanocrystals having an average particle size of 3 nm to 30 nm and a crystal structure of bcc. Was confirmed by X-ray diffraction measurement and observation using a transmission electron microscope. Further, it was confirmed by ICP analysis that there was no change in the alloy composition before and after the heat treatment.

  Table 1 describes a comparative example having a generally well-known composition of an amorphous alloy, and an example and a comparative example having a specific composition and varying the oxygen content.

  As shown in Table 1, the soft magnetic powder having the conventional composition has insufficient saturation magnetization s. Further, in Examples having a composition within a specific range and controlling the oxygen content to be 300 ppm or more and 3000 ppm or less by mass ratio, favorable results were obtained in the coercive force Hc, the saturation magnetization σs, and the resistivity ρ. Further, in the example in which the oxygen content was controlled to be not less than 800 ppm and not more than 2000 ppm, the resistivity ρ had more preferable results. On the other hand, the comparative example in which the oxygen content was less than 300 ppm even though it had a specific composition, the resistivity ρ decreased. In the comparative example having an oxygen content of more than 3000 ppm, the saturation magnetization s and the resistivity ρ were reduced.

  Table 2 mainly describes Examples and Comparative Examples in which the content (a) of M (Nb) was changed. In the example where 0 ≦ a ≦ 0.140, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ were favorable. Further, in the example where 0.040 ≦ a ≦ 0.140, the resistivity ρ was more preferable. On the other hand, in the comparative example in which a was too large, the saturation magnetization s decreased.

  Table 3 mainly describes Examples and Comparative Examples in which the B content (b) was changed. In the example where 0.020 <b ≦ 0.200, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ were favorable. Further, in the example in which 0.060 ≦ b ≦ 0.200, the resistivity ρ was more preferable. On the other hand, in the comparative example where b was too small, the soft magnetic powder before the heat treatment was composed of a crystalline phase, and the coercive force Hc after the heat treatment was significantly increased. In the comparative example where b was too large, the saturation magnetization s was reduced.

  Table 4 mainly describes Examples and Comparative Examples in which the content (c) of P was changed. In the example where 0 <c ≦ 0.150, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ gave favorable results. Further, in the example in which 0.010 ≦ c ≦ 0.150, the resistivity ρ was more preferable. On the other hand, in the comparative example where c = 0, the coercive force Hc was large. In the comparative example in which c was too large, the saturation magnetization s was reduced.

  Table 5 shows examples in which the content (a) of M (Nb), the content (b) of B, and the content (c) of P were simultaneously changed. Examples in which the content of M (Nb) (a), the content of B (b) and the content of P (c) were simultaneously changed within a specific range were all used in the examples. ρ gave favorable results.

  Table 6 mainly describes Examples and Comparative Examples in which the content (d) of Si was changed. In the example where 0 ≦ d ≦ 0.060, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ were favorable. On the other hand, in the comparative example in which d was too large, the coercive force Hc increased and the saturation magnetization s decreased.

  Table 7 mainly describes Examples and Comparative Examples in which the content (e) of C was changed. In the example where 0 ≦ e ≦ 0.030, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ showed favorable results. Further, in the example in which 0 ≦ e ≦ 0.010, the resistivity ρ was more preferable. On the other hand, in the comparative example in which e was too large, the coercive force Hc increased.

  Table 8 mainly describes Examples and Comparative Examples in which the S content (f) was changed. In the example where 0 ≦ f ≦ 0.010, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ showed favorable results. On the other hand, in the comparative example where f was too large, the coercive force Hc increased.

  Table 9 describes Examples in which Si, C, and S were simultaneously contained in Sample Nos. 34, 35, and 5, which did not contain all of Si, C, and S. In the examples in which Si, C, and S were simultaneously contained within a specific range, the coercive force Hc, the saturation magnetization s, and the resistivity ρ were all favorable.

  Table 10 shows an example in which the type of M is changed. In all the examples in which the composition was within a specific range even when the type of M was changed, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ had favorable results.

  Table 11 describes Examples in which a part of Fe was substituted with X1 and / or X2. In all the examples in which the composition was within a specific range even when a part of Fe was replaced with X1 and / or X2, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ had favorable results.

  Table 12 describes examples that do not include M (examples where a = 0). In all the examples in which the composition was within the specified range even if M was not included, the coercive force Hc, the saturation magnetization σs, and the resistivity ρ had favorable results.

(Experimental example 2)
In Experimental Example 2, an example was performed in which the temperature of the molten metal and the heat treatment conditions were changed from Sample No. 5. The results are shown in the table below. Note that Sample No. 181 had a structure in which no crystal was formed before and after the heat treatment and only an amorphous structure was formed. Sample No. 181a had a structure having only amorphous before heat treatment, and had a structure having Fe-based nanocrystals after heat treatment. Sample numbers 182 and 182a had a nanoheterostructure both before and after heat treatment. Sample numbers 182b and 183 to 189 all had a nanoheterostructure before heat treatment, and had a structure having Fe-based nanocrystals after heat treatment.

表１３より、上記の通りに構造を変化させても組成が特定の範囲内である実施例は全て保磁力Ｈｃ、飽和磁化σｓおよび抵抗率ρが好適な結果となった。

From Table 13, it can be seen that the coercive force Hc, the saturation magnetization s, and the resistivity ρ were all favorable in the examples in which the composition was within the specific range even when the structure was changed as described above.

(Experimental example 3)
In Experimental Example 3, the number of the maximum points of the Fe content ratio, the ratio of the maximum points where the coordination number is 1 or more and 5 or less, and the coordination number is 2 or more and 4 using a 3DAP (three-dimensional atom probe) for each sample. The following ratio of the maximum point and the content ratio of the Fe composition network phase to the whole sample were measured. Table 14 shows the results. In each of the examples described in Table 14, the composition was the same as that of Sample No. 5 of Experimental Example 1. The number of the maximum points and the volume ratio of the Fe composition network phase were controlled by controlling the atomizing conditions and the heat treatment temperature. Is an embodiment in which is mainly changed.

  From Table 14, when the composition of the soft magnetic powder is within a specific range, the soft magnetic powder is composed of an Fe composition network phase, and the volume ratio of the Fe composition network phase is 25 vol% or more and 50 vol% or less, the coercive force Hc, saturation magnetization s, and resistivity ρ were favorable results.

10 Grid 10a Maximum point 10b Adjacent grid 20a Area 20b with Fe content higher than threshold 20b Area with Fe content below threshold

Claims (10)

Composition formula _{(Fe (1- (α + β} )) X1 α X2 β) a soft magnetic powder comprising a main component composed of _{(1- (a + b + c} + d + e + f)) M a B b P c Si d C e S f,
X1 is one or more selected from the group consisting of Co and Ni;
X2 is at least one selected from the group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, and a rare earth element;
M is one or more selected from the group consisting of Nb, Hf, Zr, Ta, Mo, W, Ti and V;
0.040 ≦ a ≦ 0.140
0.020 <b ≦ 0.200
0 <c ≦ 0.150
0 ≦ d ≦ 0.060
0 ≦ e ≦ 0.030
0 ≦ f ≦ 0.010
α ≧ 0
β ≧ 0
0 ≦ α + β ≦ 0.50
And
A soft magnetic powder having an oxygen content of 300 ppm or more and 3000 ppm or less by mass in the soft magnetic powder.   The soft magnetic powder according to claim 1, which is amorphous.   2. The soft magnetic powder according to claim 1, wherein a nanoheterostructure comprising amorphous and microcrystals, wherein the microcrystals are present in the amorphous phase, is observed.   The soft magnetic powder according to claim 3, wherein the average diameter of the microcrystals is 0.3 to 10 nm.   The soft magnetic powder according to claim 1, wherein a structure composed of Fe-based nanocrystals is observed.   The soft magnetic powder according to claim 5, wherein the average particle diameter of the Fe-based nanocrystal is 3 nm or more and 50 nm or less. An Fe composition network phase in which a region where the Fe content is higher than the Fe content included in the entire soft magnetic powder is connected with a three-dimensional atom probe is observed,
The Fe composition network phase has a maximum point of the Fe content ratio where the Fe content ratio is locally higher than the surroundings is 400,000 / μm ³ or more,
Among all the maximum points of the Fe content ratio, the ratio of the maximum points of the Fe content ratio whose coordination number is 1 or more and 5 or less is 80% or more and 100% or less,
2. The soft magnetic powder according to claim 1, wherein a volume ratio of the Fe composition network phase in the entire soft magnetic powder is 25 vol% or more and 50 vol% or less. The soft magnetic powder according to any one of claims 1 to 7, wherein a volume resistivity in a state of being compacted at a pressure of 0.1 t / cm ² is 0.5 kΩ · cm or more and 500 kΩ · cm or less. Powder.   A green compact comprising the soft magnetic powder according to claim 1.   A magnetic component comprising the green compact according to claim 9.

Images