Soft magnetic alloys, magnetic cores and magnetic components

Abstract

The present invention provides a soft magnetic alloy that can achieve both low coercive force and high saturation magnetic flux density. (1‑α) A α ) (1‑m‑x‑y) M m X x Y y The soft magnetic alloy represented is characterized in that M is at least one selected from Zr and Hf, X is at least one selected from Ni, Mn, Cu, Co, Al and Ge, Y is at least one selected from B, P and Si, A is at least one selected from Ti, V, Cr, Zn, Mg, Sn, Bi, O, N, S and rare earth elements, m, x, y and α satisfy the relationship of 0.070≤m≤0.120, 0.001≤x≤0.030, 0≤y≤0.010, and 0≤α≤0.100, and the soft magnetic alloy has Fe-based nanocrystals with an average grain size of less than 30 nm.

Description

Technical Field

[0001] The invention relates to a soft magnetic alloy, a magnetic core and a magnetic component. Background Art

[0002] In recent years, there have been demands for miniaturization and low power consumption in electronic and information equipment, communication equipment, etc., and these demands for the realization of a low-carbon society in the future have further increased. Along with these demands, electronic components used in power circuits of electronic and information equipment, communication equipment, etc. are also required to be miniaturized and have low energy loss. Among magnetic components, which are a type of electronic component, it is known that by using a magnetic material having both high soft magnetic properties, i.e., low coercive force (Hc) and high saturation magnetic flux density (Bs), as its magnetic core, it is possible to achieve miniaturization of the magnetic component and suppress energy loss to achieve low power consumption.

[0003] To achieve miniaturization of magnetic components and reduce energy loss, development of soft magnetic alloy materials based on Fe is underway. For example, Patent Document 1 discloses an Fe-based soft magnetic alloy containing transition metals such as Zr and Hf and metalloid elements such as B. Even with a relatively high Fe concentration, the alloy exhibits specified soft magnetic properties and a relatively high saturation magnetic flux density.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 7-335419 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] As a soft magnetic alloy having both low coercivity and high saturation magnetic flux density, a soft magnetic alloy in which Fe-based nanocrystals are dispersed in an amorphous body is known. Such a soft magnetic alloy is obtained by heat treating an amorphous precursor (an amorphous alloy containing no crystals or an amorphous alloy containing microcrystals) obtained by rapidly cooling a molten metal.

[0009] In order to achieve low coercive force, the amorphous precursor before the preferred heat treatment is uniform and the precipitation of crystallization is suppressed, and by heat-treating the amorphous precursor, fine Fe-based nanocrystals are separated out in the amorphous phase. This is because, if the crystal grain size of the Fe-based nanocrystal is below about 100nm, the coercive force decreases in proportion to the sixth power of the crystal grain size.

[0010] However, when the precipitation of crystals is suppressed, there is a tendency that the transformation from amorphous to crystalline due to heat treatment is difficult to occur. The magnetization of the amorphous phase is smaller than that of the Fe-based nanocrystals. Therefore, if the amount of transformation to crystalline is small (the crystallization conversion rate is low), the saturation magnetic flux density of the soft magnetic alloy decreases.

[0011] The soft magnetic alloy disclosed in Patent Document 1 has a specific composition and structure, but cannot achieve low coercive force and high saturation magnetic flux density.

[0012] The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide a soft magnetic alloy capable of achieving both low coercive force and high saturation magnetic flux density.

[0013] Means for solving technical problems

[0014] The present inventors have found that the inclusion of "M" and "X" elements, described below, in a soft magnetic alloy having a relatively high Fe concentration promotes the crystallization and miniaturization of Fe-based nanocrystals and enables the formation of Fe-based nanocrystals at a high density.

[0015] That is, embodiments of the present invention are as follows.

[0016] [1] A soft magnetic alloy, wherein the soft magnetic alloy has a composition formula (Fe (1-α) A α ) (1-m-x-y) M m X x Y y express,

[0017] M is at least one selected from Zr and Hf,

[0018] X is at least one selected from Ni, Mn, Cu, Co, Al and Ge,

[0019] Y is at least one selected from B, P and Si,

[0020] A is at least one selected from Ti, V, Cr, Zn, Mg, Sn, Bi, O, N, S and rare earth elements,

[0021] m, x, y and α satisfy the following relationship:

[0022] 0.070≤m≤0.120,

[0023] 0.001≤x≤0.030,

[0024] 0≤y≤0.010,

[0025] 0≤α≤0.100,

[0026] The soft magnetic alloy has Fe-based nanocrystals having an average crystal grain size of 30 nm or less.

[0027] [2] The soft magnetic alloy according to [1], wherein y satisfies the relationship 0≤y≤0.005.

[0028] [3] The soft magnetic alloy according to [1] or [2], wherein X is at least one selected from Ni and Mn.

[0029] [4] A soft magnetic alloy according to any one of [1] to [3], wherein the Fe-based nanocrystals have a bcc structure, and the expansion value of the (110) plane spacing of the Fe-based nanocrystals relative to the (110) plane spacing of pure iron having a bcc structure is less than 0.020 angstroms.

[0030] [5] A magnetic core composed of the soft magnetic alloy described in any one of [1] to [4].

[0031] [6] A magnetic component comprising the soft magnetic alloy according to any one of [1] to [4], or the magnetic core according to [5].

[0032] Effects of the Invention

[0033] According to the present invention, a soft magnetic alloy capable of achieving both high saturation magnetic flux density and low coercive force can be provided. DETAILED DESCRIPTION

[0034] Hereinafter, the present invention will be described in detail based on specific embodiments in the following order.

[0035] 1. Soft magnetic alloy

[0036] 2. Manufacturing method of soft magnetic alloy

[0037] 3. Magnetic components

[0038] (1. Soft magnetic alloy)

[0039] The soft magnetic alloy involved in the present embodiment has a structure in which a plurality of Fe-based nanocrystals are dispersed in an amorphous substance. The Fe-based nanocrystals are crystals having a crystal grain size of nanometer order and a high Fe concentration. In the present embodiment, the average crystal grain size of the Fe-based nanocrystals exceeds 0 nm and is below 30 nm, preferably exceeds 0 nm and is below 15 nm. Because a plurality of fine Fe-based nanocrystals are dispersed in an amorphous substance, the soft magnetic alloy involved in the present embodiment can show high saturation magnetic flux density and low coercive force.

[0040] Next, the composition of the soft magnetic alloy according to this embodiment will be described in detail.

[0041] The composition of the soft magnetic alloy according to this embodiment is represented by the composition formula (Fe (1-α) A α ) (1-m-x-y) M m X x Y y express.

[0042] In the present embodiment, the soft magnetic alloy contains Fe (iron), an "M" element, and an "X" element as essential components.

[0043] The "M" element is at least one element selected from Zr (zirconium) and Hf (hafnium).

[0044] The "X" element is at least one element selected from Ni (nickel), Mn (manganese), Cu (copper), Co (cobalt), Al (aluminum), and Ge (germanium). The "X" element is preferably at least one element selected from Ni and Mn.

[0045] The soft magnetic alloy according to the present embodiment is obtained by heat-treating an amorphous precursor obtained by rapidly cooling a molten alloy containing the above-mentioned components.

[0046] In this embodiment, since the molten alloy contains the "M" element, even if the molten alloy is rapidly cooled, an amorphous precursor in which Fe crystallization is suppressed can be obtained. In addition, even if such an amorphous precursor is heat-treated, Fe-based nanocrystals are precipitated in the amorphous phase, and their grain growth is suppressed, thereby easily making the average crystal grain size of the Fe-based nanocrystals within the above-mentioned range.

[0047] As the reason for suppressing the crystallization of Fe, it is believed that there are the following reasons. The atomic radius and atomic weight of the "M" element are larger than those of Fe. Therefore, when Fe atoms gather as crystals and precipitate in the alloy, the "M" element acts as an obstacle that hinders the movement of Fe atoms. Therefore, the growth of the crystallization caused by the aggregation of Fe atoms is hindered. As a result, a homogeneous amorphous precursor can be formed even in a composition with a high Fe concentration. And then, when the amorphous precursor is heat-treated, the miniaturization of Fe-based nanocrystallization is promoted, so that a soft magnetic alloy with high saturation flux density and low coercive force can be obtained.

[0048] The "X" element has the following characteristics: within the temperature range of heat treatment, the mixing enthalpy (ΔHmix) between the "X" element and Fe is greater than the mixing enthalpy (ΔHmix) between the "X" element and the "M" element. Therefore, when the amorphous precursor is heat treated, the "X" element tends to move away from the Fe and toward the "M" element. As a result, the "X" element is located between the Fe and "M" elements that form the stable amorphous phase, tending to separate the Fe and "M" elements. This promotes the aggregation of Fe atoms and the accompanying crystallization.

[0049] By such mechanism, even the amorphous alloy that contains Fe, " M " element and " X " element is carried out heat treatment at relatively low temperature and can obtain high crystallization conversion.In addition, by heat treating at low temperatures, compare with the grain growth process of Fe-based nano-crystalline, the nucleation process of Fe-based nano-crystalline occupies a dominant position, therefore, forms fine Fe-based nano-crystalline at high density.In addition, owing to can heat treating at low temperatures, therefore, be difficult to side reaction, also can avoid the formation of heterogeneous phase.

[0050] Furthermore, as described above, Fe and the “M” element are separated in the stage of crystallization of the Fe-based nanocrystals, and thus supersaturated solid solution of the “M” element in the Fe-based nanocrystals is also suppressed.

[0051] In this way, by including the "X" element in addition to the "M" element, the advantage of obtaining a homogeneous amorphous precursor even at a high Fe concentration can be achieved, and the problems encountered when heat treating the amorphous precursor can be solved. As a result, a soft magnetic alloy can be obtained that achieves both high saturation magnetic flux density and low coercive force.

[0052] From the viewpoint of obtaining the above-mentioned effects, the content ratios of the "M" element and the "X" element satisfy the following ranges.

[0053] In the above composition formula, "m" represents the content ratio of the "M" element. In this embodiment, "m" satisfies the relationship 0.070 ≤ m ≤ 0.120. "m" is preferably 0.080 or greater, more preferably 0.090 or greater. Furthermore, "m" is preferably 0.110 or less.

[0054] No matter " m " is too little or too large, when the molten alloy is quenched, crystallization is separated out easily, and there is the tendency that can not obtain homogeneous amorphous precursor.As a result, there is the tendency that is difficult to obtain fine Fe-based nano-crystallization when the thermal treatment of amorphous precursor.Therefore, there is the tendency that the coercive force of the soft magnetic alloy after the thermal treatment becomes higher.In addition, when " m " is too large, owing to can not form Fe-based nano-crystallization at high density, therefore, the saturation magnetic flux density of the soft magnetic alloy after the thermal treatment has the tendency to reduce.

[0055] In the above composition formula, "x" represents the content ratio of the element "X". In this embodiment, "x" satisfies the relationship 0.001≤x≤0.030. "x" is preferably greater than or equal to 0.005, more preferably greater than or equal to 0.010. Furthermore, "x" is preferably less than or equal to 0.020.

[0056] When "x" is too small, there is a tendency to not sufficiently obtain fine Fe-based nanocrystals, and further, the density of the Fe-based nanocrystals that bear magnetization tends to decrease. As a result, the coercivity of the soft magnetic alloy after heat treatment increases, and there is a tendency for the saturation magnetic flux density to decrease. On the other hand, when "x" is too large, since Fe-based nanocrystals cannot be formed at a high density, the saturation magnetic flux density of the soft magnetic alloy after heat treatment tends to decrease.

[0057] The soft magnetic alloy according to the present embodiment may contain a "Y" element as an optional component. The "Y" element is at least one element selected from the group consisting of B (boron), P (phosphorus), and Si (silicon).

[0058] By containing " Y " element, the homogeneous amorphous formation during liquid phase quenching or gas phase quenching becomes easy.In addition, the miniaturization of crystallization when also promoting thermal treatment.Particularly under the situation that contains Si in soft magnetic alloy, except above-mentioned effect, also can obtain the effect of the crystallographic magnetic anisotropy that reduces Fe-based nano-crystalline.As a result, there is the tendency that the soft magnetic characteristics of soft magnetic alloy improves.

[0059] In the above composition formula, "y" represents the content ratio of the "Y" element. In the present embodiment, "y" satisfies the relationship of 0≤y≤0.010. When the soft magnetic alloy contains the "Y" element, "y" satisfies 0<y≤0.010. If "y" is too large, the saturation magnetic flux density of the soft magnetic alloy tends to decrease, which is not preferred.

[0060] "y" is preferably not less than 0.002. In addition, "y" is preferably not more than 0.005, and more preferably not more than 0.004.

[0061] The soft magnetic alloy according to this embodiment may also contain an "A" element as an optional component. The "A" element is at least one element selected from the group consisting of Ti (titanium), V (vanadium), Cr (chromium), Zn (zinc), Mg (magnesium), Sn (tin), Bi (bismuth), O (oxygen), N (nitrogen), S (sulfur), and rare earth elements. In this embodiment, the rare earth elements are Sc (scandium), Y (yttrium), and elements with atomic numbers 57 to 71 (lanthanides).

[0062] In the above composition formula, "α" represents the content ratio of the "A" element. In the present embodiment, "α" satisfies 0.000 ≤ α ≤ 0.100. When the soft magnetic alloy contains the "A" element, "α" satisfies 0.000 < α ≤ 0.100. "α" is preferably 0.050 or less, and more preferably 0.030 or less.

[0063] The soft magnetic alloy according to the present embodiment can obtain the above-mentioned effects even if it contains the element "A" within the above-mentioned range.

[0064] In the above composition formula, "(1-α) × (1-mxy)" represents the Fe (iron) content in the soft magnetic alloy. As long as m, x, y, and α are within the above ranges, the Fe content is not particularly limited. In this embodiment, the Fe content "(1-α) × (1-mxy)" is preferably 0.85 or greater, and more preferably 0.88 or greater. By keeping the Fe content within the above range, a high saturation magnetic flux density can be easily obtained.

[0065] It should be noted that the soft magnetic alloy according to this embodiment may contain elements other than the above as inevitable impurities. For example, the soft magnetic alloy may contain 0.1% by mass or less of the above elements in total relative to 100% by mass of the soft magnetic alloy.

[0066] In addition, in the present embodiment, the lattice spacing of Fe-based nanocrystals is focused on. In the present embodiment, Fe-based nanocrystals have a bcc structure, so the lattice spacing of the bcc structure is focused on. The soft magnetic alloy involved in the present embodiment contains an "M" element with high amorphous forming ability as an element other than Fe. Therefore, in the amorphous precursor before heat treatment, the "M" element and Fe are almost uniformly dispersed. Since the diffusion rate of such an "M" element is slow, when Fe atoms crystallize during the heat treatment of the amorphous precursor, the "M" element is absorbed into the crystallization, and the crystallization formed as a result becomes a crystallization with a bcc structure having a supersaturated solid solution of "M".

[0067] Because the atomic radius of the "M" element is larger than that of Fe, when the "M" element enters a crystal with a bcc structure (hereinafter referred to as a bcc crystal), the bcc crystal deforms. This lattice deformation reduces the magnetization of the crystal. Therefore, the magnetization of the bcc crystal deformed by the "M" element's solid solution is reduced compared to that of pure iron bcc crystals. As a result, the saturation magnetic flux density of the soft magnetic alloy tends to decrease.

[0068] Therefore, in the present embodiment, the expansion of the lattice spacing of the crystals caused by the deformation of the bcc crystals accompanying the solid solution of the "M" element is controlled.

[0069] In this embodiment, the spacing of the (110) planes of the bcc crystals is used as the lattice spacing of the bcc crystals. Since pure iron does not contain the "M" element, the "M" element is not dissolved in the bcc crystals of pure iron. In other words, the expansion of the plane spacing due to the solid solution of the "M" element in the bcc crystals does not occur. Therefore, the closer the spacing of the (110) planes of the soft magnetic alloy is to the spacing of the (110) planes of pure iron, the lower the proportion of the "M" element dissolved in the bcc crystals.

[0070] In this embodiment, the value obtained by subtracting the spacing between (110) planes of pure iron from the spacing between (110) planes of the soft magnetic alloy is defined as the expansion value of the (110) plane spacing. The expansion value of the (110) plane spacing is preferably 0.020 angstroms or less, and more preferably 0.010 angstroms or less.

[0071] As described above, by including an "X" element in addition to the "M" element in the soft magnetic alloy, Fe and the "M" element are separated, which can suppress the solid solution of the "M" element in the bcc crystal. Furthermore, by controlling the heat treatment conditions of the amorphous precursor with the same composition, it is also easy to adjust the expansion value of the (110) plane spacing of the bcc crystal to the above range.

[0072] Specifically, it is preferable to perform a relatively long heat treatment at an appropriate temperature. This is because, during the heat treatment process, while crystals are precipitating, the supersaturated solid solution components are also being expelled from the precipitated crystals. Therefore, extending the heat treatment time can promote the expulsion of the supersaturated solid solution components. As a result, the expansion value of the interplanar spacing becomes smaller, and as mentioned above, the saturation magnetic flux density increases.

[0073] In addition, also can carry out heat treatment in multiple stages.For example, carry out short time heating at appropriate temperature and make fine Fe-based nano-crystallization high density separate out, then at relatively low temperature long time heat treatment and supersaturated solid solution component is discharged from Fe-based nano-crystallization.Thus, can well-balancedly realize the reduction of high crystallization conversion, fine Fe-based nano-crystallization separation and plane spacing expansion.

[0074] Need to prove, when carrying out heat treatment at high temperature, can carry out the discharge of supersaturated solid solution composition at short notice, on the other hand, also promote the grain growth of Fe-based nano-crystalline, there is the tendency of Fe-based nano-crystalline coarsening, soft magnetic properties deterioration, thereby not preferably.On the other hand, under the too low situation of heat treatment temperature, even prolong the heat treatment time, the crystallization conversion rate also can not fully rise, and has the tendency that can not fully discharge supersaturated solid solution composition.As a result, there is the tendency that saturation magnetic flux density reduces.Therefore, heat treatment temperature is preferably too high situation or too low situation, preferably separates out at fine crystal grain and supersaturated solid solution composition and carries out heat treatment under the optimum temperature that discharges fully.

[0075] The spacing between the (110) planes of soft magnetic alloys and pure iron can be calculated using XRD (X-ray Diffraction) measurements. Specifically, the spacing between the (110) planes can be calculated based on the angle at which the diffraction peak of the (110) planes is observed and the wavelength of the X-rays. Based on the calculated spacing, the expansion value of the (110) plane spacing can be calculated.

[0076] It should be noted that in order to reduce the influence of the inherent error of the XRD measurement device, the spacing between the (110) planes of the soft magnetic alloy and the spacing between the (110) planes of pure iron are preferably measured using the same device and the same measurement conditions.

[0077] The shape of the soft magnetic alloy involved in this embodiment is not particularly limited. For example, a film shape, a thin ribbon shape, or a powder shape can be exemplified. The difference in these shapes mainly arises from the difference in the manufacturing method of the soft magnetic alloy described later.

[0078] (2. Method for producing soft magnetic alloy)

[0079] Next, the method for manufacturing the soft magnetic alloy is described. The soft magnetic alloy involved in this embodiment is manufactured, for example, by precipitating Fe-based nanocrystals in an amorphous precursor having the above-mentioned composition. As a method for obtaining an amorphous precursor, for example, a method for forming an amorphous precursor using a known thin film forming method, a method for obtaining an amorphous precursor by rapidly cooling a molten metal can be exemplified.

[0080] In this embodiment, a method of manufacturing a soft magnetic alloy in the shape of a thin film by heat-treating an amorphous precursor obtained by a known thin film forming method; a method of manufacturing a soft magnetic alloy in the shape of a thin strip by heat-treating an amorphous precursor obtained by a roller method; and a method of manufacturing a soft magnetic alloy in the shape of a powder by heat-treating an amorphous precursor obtained by an atomization method.

[0081] First, a method for manufacturing a soft magnetic alloy by a known thin film forming method is described. As a known thin film forming method, there is no particular limitation, and examples thereof include PVD (physical vapor deposition) such as evaporation, sputtering, PLD (pulsed laser evaporation), and CVD (chemical vapor deposition). Therefore, the thin film formed by these thin film forming methods is a deposited film formed by temporarily decomposing the raw materials into atomic or molecular levels and then depositing them on a substrate. Below, a method for manufacturing a soft magnetic alloy using a sputtering method is described.

[0082] When sputtering is used, a target of the desired composition is used to form an amorphous precursor in the form of a thin film on a substrate. As the target, a target composed of a single substance of each element contained in a plurality of soft magnetic alloys can be used, or an alloy target containing some or all of each element can be used. Furthermore, a target composed of a single substance of each element and an alloy target can be used in combination.

[0083] The substrate is not particularly limited as long as it is made of a material capable of supporting the thin film during the heat treatment described below. Examples thereof include silicon substrates, silicon substrates with thermal oxide films, ferrite substrates, non-magnetic ferrite substrates, sapphire substrates, glass substrates, and glass epoxy substrates. Furthermore, to ensure adhesion between the substrate and the thin film, a base layer may be formed on the substrate.

[0084] From the viewpoint of obtaining an amorphous precursor, the film formation conditions are preferably a substrate temperature of 300° C. or lower, a pressure of 0.1 to 1.0 Pa, and an Ar atmosphere.

[0085] The thickness of the formed thin film is preferably 10 to 2000 nm.

[0086] Next, a method for manufacturing a soft magnetic alloy using a roller method is described. In this embodiment, a single roller method is used as the roller method. In the single roller method, first, raw materials (pure metals, etc.) of each metal element contained in the soft magnetic alloy are prepared, weighed in such a manner as to become the composition of the final soft magnetic alloy, and the raw materials are melted to obtain molten metal. It should be noted that there is no particular limitation on the method for melting the raw materials of the metal elements. For example, a method of melting by high-frequency heating under a specified atmosphere can be exemplified. The temperature of the molten metal can be determined by considering the melting point of each metal element, for example, it can be set to 1200-1500°C.

[0087] Next, for example, within a chamber filled with an inert gas, molten metal is sprayed from a nozzle onto a cooled rotating roller and supplied in the direction of rotation of the rotating roller, thereby producing a thin ribbon-shaped amorphous precursor. Examples of materials for the rotating roller include copper. The temperature of the rotating roller, the rotational speed of the rotating roller, the atmosphere within the chamber, and the like can be determined based on conditions that facilitate the precipitation of Fe-based nanocrystals within the amorphous material during the heat treatment described below.

[0088] Next, the method for producing a soft magnetic alloy using an atomization method is described. In this embodiment, a gas atomization method is used as the atomization method. In the gas atomization method, as in the single-roll method, a molten metal is first obtained by melting the raw materials of the soft magnetic alloy. As in the single-roll method, the temperature of the molten metal can be determined by considering the melting points of the various metal elements, for example, 1200-1500°C.

[0089] The obtained molten metal is supplied to the chamber as a linear continuous fluid by the nozzle arranged at the crucible bottom, the supplied molten metal is blown with high pressure gas, the molten metal is dropletized, and quenched to obtain a powdered amorphous precursor. About the pressure in the gas injection temperature, the chamber etc. according to the thermal treatment described later, the condition of easily separating out Fe-based nano-crystallization in amorphous is determined. In addition, for particle diameter, granularity can be adjusted by screening classification or air flow classification etc.

[0090] The film, ribbon and powder obtained by the above method are composed of an amorphous precursor. The amorphous precursor can be an amorphous alloy in which microcrystals are dispersed in an amorphous substance, or it can be an amorphous alloy that does not contain crystals, but is more preferably an amorphous alloy that does not contain crystals. Whether the film, ribbon and powder are composed of an amorphous precursor can be determined by whether crystals are not precipitated in the amorphous substance or whether microcrystals of a specified size or less are formed in the amorphous substance. In the present embodiment, it can be determined, for example, by X-ray diffraction measurement.

[0091] Next, the obtained thin film, ribbon, and powder are subjected to heat treatment. By performing the heat treatment, a soft magnetic alloy in which Fe-based nanocrystals are precipitated can be obtained.

[0092] In the present embodiment, the heat treatment conditions are not particularly limited as long as they are conditions under which Fe-based nanocrystallization is precipitated and its average crystal grain size is within the above-mentioned range. For example, if it is normal pressure, then N2 atmosphere or Ar atmosphere can be used; if it is vacuum, then the pressure can be set to below 1 Pa, the heat treatment temperature can be set to 350-700°C, and the holding time can be set to 0-5 hours.

[0093] From the viewpoint of promoting the discharge of elements other than Fe dissolved in Fe-based nanocrystals and reducing the (110) plane spacing expansion value, it is preferred to set the heat treatment temperature to 450-600°C and the holding time to 0.5-4 hours.

[0094] In addition, in order to promote the discharge of elements other than Fe dissolved in the Fe-based nanocrystal, heat treatment can also be carried out in multiple stages. For example, as the initial heat treatment (first temperature holding stage), it is preferred that the heat treatment temperature is set to 450 to 600° C. and the holding time is set to 0.25 to 0.75 hour.

[0095] Next, in the next heat treatment (second temperature holding stage), the heat treatment temperature is preferably set to 350 to 450° C., and the holding time is preferably set to 0.5 to 2 hours.

[0096] After heat treatment, a soft magnetic alloy in the form of a film in which Fe-based nanocrystals are precipitated, a soft magnetic alloy in the form of a ribbon in which Fe-based nanocrystals are precipitated, or a soft magnetic alloy in the form of a powder in which Fe-based nanocrystals are precipitated can be obtained.

[0097] In this embodiment, the following method is used as a method for calculating the average crystal grain size of Fe-based nanocrystals contained in the soft magnetic alloy obtained by heat treatment. First, a transmission electron microscope is used to measure the average grain size of the Fe-based nanocrystals at a magnification of 1×10 5 Times ~ 1×10 6 Times, to obtaining bright field image by the sample of ion milling thinning.In the bright field image obtained, by measuring the diameter of more than 100 grain images and find out mean value, thereby can calculate the average crystal grain size of Fe-based nano-crystalline.The diameter of each grain image can be by finding out the area of ​​grain image according to the number of pixels that forms grain image, find out according to the area calculation circle equivalent diameter, but when grain image is circular, also can use straight-line distance measurement diameter.In addition, confirm that crystalline structure is the method for Fe-based nano-crystalline with bcc (body centered cubic lattice) structure and is not particularly limited.For example, can confirm by carrying out X-ray diffraction measurement.

[0098] (3. Magnetic components)

[0099] The magnetic component according to the present embodiment may include the soft magnetic alloy as a magnetic body, or may include a magnetic core made of the soft magnetic alloy.

[0100] Examples of methods for producing magnetic cores from thin-film soft magnetic alloys include laminating thin-film soft magnetic alloys. Examples of methods for producing magnetic cores from ribbon-shaped soft magnetic alloys include winding ribbon-shaped soft magnetic alloys and laminating ribbon-shaped soft magnetic alloys. Laminating thin-film or ribbon-shaped soft magnetic alloys through an insulator allows for the production of magnetic cores with superior properties.

[0101] Methods for producing magnetic cores from soft magnetic alloy powders include, for example, mixing the powdered soft magnetic alloy with a binder and then molding the mixture using a mold. Furthermore, prior to mixing with the binder, the powder surface can be oxidized or treated with an insulating coating to increase the resistivity of the core, resulting in a core more suitable for high-frequency bands.

[0102] The magnetic component according to this embodiment is suitable for a power inductor used in a power supply circuit. In addition, examples of magnetic components include transformers, motors, and the like in addition to inductors.

[0103] As mentioned above, although embodiment of this invention was demonstrated, this invention is not limited to the said embodiment, It can also be changed in various aspects within the scope of this invention.

[0104] Example

[0105] Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[0106] (Experiment 1)

[0107] First, raw metals of a soft magnetic alloy were prepared. The prepared raw metals were weighed to give the composition shown in Table 1 and melted by high-frequency heating to prepare a mother alloy.

[0108] The master alloy is then heated to melt, yielding a molten metal with a melting temperature of 1250°C. Using a single-roll method, the molten metal is ejected from a slit nozzle onto a rotating roller and rapidly cooled, thereby producing a thin ribbon (amorphous precursor). The slit width of the slit nozzle is set to 180 mm, the distance from the slit opening to the roller is set to 0.2 mm, the rotating roller is made of Cu, and the rotation speed is set to 25 m / sec. This results in a thin ribbon with a thickness of 20 to 30 μm and a length of several tens of meters.

[0109] Each of the obtained ribbons was subjected to X-ray diffraction measurement to confirm whether the amorphous precursor consisted of an amorphous phase or a crystalline phase. The results are shown in Table 1.

[0110] Then, for each ribbon, the pressure was 2×10 -4 Heat treatment was performed in a vacuum of 1 Pa or less at a temperature of 475°C and a holding time of 1 hour. The heat-treated ribbon was observed using a transmission electron microscope to observe the Fe-based nanocrystals, and the average grain size of the Fe-based nanocrystals was calculated. The results are shown in Table 1. In addition, ICP analysis confirmed that the alloy composition did not change before and after the heat treatment.

[0111] The saturation magnetic flux density and coercive force of the heat-treated ribbon were measured using the following methods. The saturation magnetic flux density (Bs) was measured using a vibrating sample magnetometer (VSM) at a magnetic field of 1000 (Oe). The coercive force (Hc) was measured using an Hc meter.

[0112] Regarding the saturation magnetic flux density of the ribbon, samples with a saturation magnetic flux density of 1.51 T or higher were considered good. More preferably, samples with a saturation magnetic flux density of 1.60 T or higher were considered good, and even more preferably, samples with a saturation magnetic flux density of 1.70 T or higher were considered good. Regarding the coercive force of the ribbon, samples with a coercive force of less than 15.0 A / m were considered good. More preferably, samples with a coercive force of less than 7.0 A / m were considered good, and even more preferably, samples with a coercive force of less than 5.0 A / m were considered good. The results are shown in Table 1.

[0113] Next, the heat-treated ribbon was used to create a magnetic core. First, the ribbon was cut into 310mm long ribbon slices in the casting direction. The cut ribbon slices were then punched into 120 ring-shaped pieces with an outer diameter of 18mm and an inner diameter of 10mm. The punched ribbon slices were stacked to create a stacked toroidal magnetic core approximately 3mm high.

[0114] For the laminated toroidal core, the saturation magnetic flux density (Bs) and coercive force (Hc) were measured using a DC BH analyzer.

[0115] Regarding the saturation magnetic flux density of the magnetic core, samples with a saturation magnetic flux density of 1.26 T or higher were considered good. More preferred were samples with a saturation magnetic flux density of 1.36 T or higher, and even more preferred were samples with a saturation magnetic flux density of 1.45 T or higher. Regarding the coercive force of the magnetic core, samples with a coercive force of less than 18.0 A / m were considered good. More preferred were samples with a coercive force of less than 9.0 A / m, and even more preferred were samples with a coercive force of less than 6.5 A / m. The results are shown in Table 1.

[0116] The effects of the present invention are achieved by achieving both high saturation flux density and low coercive force. Therefore, in Table 1 and Tables 2 to 5 described below, each sample is assigned a score corresponding to the measured characteristic values, and the product of these scores is used to comprehensively evaluate the quality of the sample. The results are shown in the "Comprehensive Evaluation" column.

[0117] For each thin strip sample, 0 points were assigned when the saturation magnetic flux density was 1.50 T or less, 1 point was assigned when the saturation magnetic flux density was 1.51 T or more and less than 1.60 T, 2 points were assigned when the saturation magnetic flux density was 1.60 T or more and less than 1.70 T, and 3 points were assigned when the saturation magnetic flux density was 1.70 T or more.

[0118] In addition, for each thin strip sample, 0 points were assigned when the coercive force was greater than 15.0 A / m, 1 point was assigned when the coercive force was greater than 7.0 A / m and less than 15.0 A / m, 2 points were assigned when the coercive force was greater than 5.0 A / m and less than 7.0 A / m, and 3 points were assigned when the coercive force was less than 5.0 A / m.

[0119] Then, the product of the assigned values ​​is calculated, and samples with a product value of 1 or greater are judged as good. In other words, when the product value is 1 or greater, the ribbon-shaped soft magnetic alloy is judged to have both low coercive force and high saturation magnetic flux density.

[0120] For each sample of the magnetic core, 0 points were assigned when the saturation magnetic flux density was 1.25 T or less, 1 point was assigned when the saturation magnetic flux density was 1.26 T or more and 1.35 T or less, 2 points were assigned when the saturation magnetic flux density was 1.36 T or more and 1.44 T or less, and 3 points were assigned when the saturation magnetic flux density was 1.45 T or more.

[0121] In addition, for each sample of the magnetic core, 0 points were assigned when the coercive force was greater than 18.0 A / m, 1 point was assigned when the coercive force was greater than 9.0 A / m and less than 18.0 A / m, 2 points were assigned when the coercive force was greater than 6.5 A / m and less than 9.0 A / m, and 3 points were assigned when the coercive force was less than 6.5 A / m.

[0122] Then, the product of the assigned values ​​is calculated, and samples with a product value of 1 or greater are judged as good. In other words, when the product value is 1 or greater, the core comprising the soft magnetic alloy is judged to have both low coercive force and high saturation magnetic flux density.

[0123]

[0124] From Table 1, it can be confirmed that even when the content ratio of the "M" element is changed within the above range, the value of the product is 4 or more.

[0125] In contrast, it was confirmed that when the "M" element content was too low (Comparative Examples 1 and 3), low coercivity could not be achieved. It was confirmed that when the "M" element content was too high (Comparative Examples 2 and 4), high saturation magnetic flux density and low coercivity could not be achieved. Furthermore, it was confirmed that when the "M" element was not one of the above elements (Comparative Example 5), high saturation magnetic flux density and low coercivity could not be achieved.

[0126] (Experiment 2)

[0127] Except that the "X" element and its content ratio in the samples of Examples 3 and 6 were changed to the elements and content ratios shown in Table 2, thin ribbon-shaped soft magnetic alloys and magnetic cores obtained by laminating the thin ribbons were prepared by the same method as Experiment 1, and the same evaluation as Experiment 1 was performed. The results are shown in Table 2.

[0128]

[0129] Table 2 shows that good properties can be obtained even when the "X" element and its content ratio are changed. In particular, it can be confirmed that even better properties can be obtained when Ni and Mn are contained as the "X" element.

[0130] On the other hand, it was confirmed that high saturation magnetic flux density and low coercive force could not be obtained if the "X" element was not contained. In addition, it was confirmed that high saturation magnetic flux density and low coercive force could not be obtained even if the "X" element content was too high.

[0131] (Experiment 3)

[0132] Except that the samples of Examples 3 and 17 contained the "Y" element shown in Table 3 and its content ratio was the same as that in Table 3, a soft magnetic alloy in the form of a thin ribbon and a magnetic core obtained by laminating the thin ribbons were produced by the same method as Experiment 1, and the same evaluation as Experiment 1 was performed. The results are shown in Table 3.

[0133]

[0134] Table 3 shows that good properties can be obtained if the "Y" element is contained and its content is within the above range. In particular, it can be confirmed that even better properties can be obtained if the "Y" element content is 0.005 or less.

[0135] On the other hand, it was confirmed that when the content ratio of the "Y" element exceeds the above range, the saturation magnetic flux density is particularly reduced.

[0136] (Experiment 4)

[0137] Except that the "A" element and its content ratio in the samples of Examples 3 and 17 were changed to the elements and content ratios shown in Table 4, a soft magnetic alloy in the form of a ribbon and a magnetic core obtained by laminating the ribbons were prepared by the same method as in Experiment 1, and the same evaluation as in Experiment 1 was performed. The results are shown in Table 4.

[0138]

[0139] From Table 4, it can be confirmed that even if the "A" element is contained, good characteristics can be obtained as long as the content ratio is within the above-mentioned range.

[0140] (Experiment 5)

[0141] Except that in the samples of Example 3 and Comparative Example 6, the heat treatment conditions were set to the conditions shown in Table 5, the soft magnetic alloy in the shape of a thin strip and the magnetic core obtained by stacking the thin strips were made by the same method as Experiment 1. In addition to the same evaluation as Experiment 1, the spacing of the (110) planes of the soft magnetic alloy was also calculated.

[0142] The spacing of the (110) planes is calculated from the 2θ of the peak of the (110) plane belonging to the bcc structure in the diffraction peak obtained by XRD measurement and the wavelength of the measured X-ray. In addition, for the sample of pure iron, the spacing of the (110) planes is calculated under the conditions of the above-mentioned XRD measurement using the same apparatus as the apparatus for performing the above-mentioned XRD measurement. The plane spacing value of the (110) planes of the obtained pure iron is subtracted from the plane spacing value of the (110) planes of the obtained soft magnetic alloy to obtain the (110) plane spacing expansion value in the samples of Examples 3, 70 to 86 and Comparative Examples 6, 16 to 19. The results are shown in Table 5.

[0143]

[0144] According to Table 5, it can be confirmed that when the holding temperature is too high, the (110) plane spacing expansion value becomes smaller and the saturation magnetic flux density increases, but there is a tendency for the grain size to become larger and the coercive force to become larger. It can be confirmed that when the holding temperature is too low, the grain size is small and the coercive force is small, but the plane spacing expansion is large, and even if the holding time is extended, sufficient saturation magnetic flux density cannot be obtained. On the other hand, it can be confirmed that if the holding time is extended at an appropriate temperature, the plane spacing expansion becomes smaller, the saturation magnetic flux density increases, and the increase in the grain size and the accompanying increase in coercive force are extremely small. Furthermore, it can be confirmed that by performing a first-stage heat treatment at an appropriate temperature and then a second-stage long-term heat treatment at a relatively low temperature, it is possible to obtain fine Fe-based nanocrystals with small plane spacing expansion, and it is possible to obtain a soft magnetic alloy with small coercive force and high saturation magnetic flux density.

[0145] (Experiment 6)

[0146] In Experiment 6, unlike Experiments 1 to 5 in which a soft magnetic alloy in a strip shape was produced, a soft magnetic alloy in a thin film shape was produced as follows.

[0147] First, targets of each metal element or alloy contained in the soft magnetic alloy and chips were prepared as targets. Using the prepared targets and, if necessary, targets equipped with chips, thin films having the compositions shown in Table 6 were formed to a thickness of 150 nm on a Si wafer with a thermal oxide film. A magnetron sputtering apparatus (SPF430H manufactured by Canon Anelva Corporation) was used as the sputtering apparatus.

[0148] The film formation conditions were as follows: substrate temperature was 80 to 100° C., pressure during film formation was 0.3 Pa, and atmosphere during film formation was Ar atmosphere.

[0149] The thin film immediately after film formation was subjected to X-ray diffraction measurement by the same method as in Experiment 1 to confirm whether the amorphous precursor consisted of an amorphous phase or a crystalline phase.

[0150] For the obtained film, the same conditions as those in Experiment 1, i.e., the pressure was 2×10 -4 Heat treatment was performed in a vacuum of 1.5 Pa or less at a temperature of 475°C for 1 hour. The post-heat-treatment film was observed using a transmission electron microscope to observe the Fe-based nanocrystals, and the average grain size of the Fe-based nanocrystals was calculated. The results are shown in Table 6. In addition, ICP analysis confirmed that the alloy composition did not change before and after the heat treatment.

[0151] The saturation magnetic flux density and coercive force of the thin film after the heat treatment were measured by the same method as in Experiment 1.

[0152] Regarding the saturation magnetic flux density of the film, samples with a saturation magnetic flux density of 1.47T or more are judged to be good. More preferably, the sample is 1.55T or more, and even more preferably, the sample is 1.65T or more. Regarding the coercive force of the film, samples with a coercive force of less than 18.0 (Oe) are judged to be good. More preferably, the sample is less than 8.5 (Oe), and even more preferably, the sample is less than 6.0 (Oe). The coercive force of the film is different from the coercive force of the thin strip, and the unit of the measured value is Oersted. Even with the same composition, the characteristic value varies depending on the shape.

[0153] As in Experiments 1 to 5, each sample was assigned a score corresponding to the measured characteristic value, and the quality of the sample was comprehensively evaluated based on the numerical value of the product of these scores. The results are shown in the "Comprehensive Evaluation" column.

[0154] For each sample of the thin film, 0 points were assigned when the saturation magnetic flux density was less than 1.47 T, 1 point was assigned when the saturation magnetic flux density was greater than 1.47 T and less than 1.55 T, 2 points were assigned when the saturation magnetic flux density was greater than 1.55 T and less than 1.65 T, and 3 points were assigned when the saturation magnetic flux density was greater than 1.65 T.

[0155] In addition, for each sample of the thin film, 0 points were assigned when the coercive force was 18.0 (Oe) or more, 1 point was assigned when the coercive force was 8.5 (Oe) or more and less than 18.0 (Oe), 2 points were assigned when the coercive force was 6.0 (Oe) or more and less than 8.5 (Oe), and 3 points were assigned when the coercive force was less than 6.0 (Oe).

[0156] Then, the product of the assigned values ​​is calculated, and samples with a product value of 1 or greater are judged to be good. In other words, when the product value is 1 or greater, the soft magnetic alloy in the thin film shape is judged to have both low coercive force and high saturation magnetic flux density.

[0157] [Table 6]

[0158]

[0159] From Table 6, it can be confirmed that even when the content ratio of the "M" element is changed within the above-mentioned range, the numerical value of the product is 4 or more.

[0160] In contrast, it was confirmed that when the "M" element content was too low (Comparative Examples 20 and 22), low coercivity could not be achieved. It was confirmed that when the "M" element content was too high (Comparative Examples 21 and 23), high saturation magnetic flux density and low coercivity could not be achieved. Furthermore, it was confirmed that when the "M" element was not one of the above elements (Comparative Example 24), high saturation magnetic flux density and low coercivity could not be achieved.

[0161] (Experiment 7)

[0162] Soft magnetic alloy films were prepared by the same method as in Experiment 6, except that the "X" element and its content ratio in the samples of Examples 89 and 92 were changed to the elements and content ratios shown in Table 7. The same evaluation as in Experiment 6 was performed. The results are shown in Table 7.

[0163] [Table 7]

[0164]

[0165] Table 7 shows that good properties can be obtained even when the "X" element and its content ratio are changed. In particular, it can be confirmed that even better properties can be obtained when Ni and Mn are contained as the "X" element.

[0166] On the other hand, it was confirmed that high saturation magnetic flux density and low coercive force could not be obtained if the "X" element was not contained. In addition, it was confirmed that high saturation magnetic flux density and low coercive force could not be obtained even if the "X" element content was too high.

[0167] (Experiment 8)

[0168] Soft magnetic alloy films were prepared by the same method as in Experiment 6, except that the "Y" element shown in Table 8 was contained in the samples of Examples 89 and 103 at the content ratios shown in Table 8. The same evaluation as in Experiment 6 was performed. The results are shown in Table 8.

[0169] [Table 8]

[0170]

[0171] Table 8 shows that good properties can be obtained when the "Y" element is contained and its content is within the above range. In particular, it can be confirmed that even better properties can be obtained when the "Y" element content is 0.005 or less.

[0172] On the other hand, it was confirmed that when the content ratio of the "Y" element exceeds the above range, the saturation magnetic flux density is particularly reduced.

[0173] (Experiment 9)

[0174] Soft magnetic alloy films were prepared by the same method as in Experiment 6, except that the "A" element and its content ratio in the samples of Examples 89 and 103 were changed to the elements and content ratios shown in Table 9. The same evaluation as in Experiment 6 was performed. The results are shown in Table 9.

[0175] [Table 9]

[0176]

[0177] From Table 9, it can be confirmed that even if the "A" element is contained, good characteristics can be obtained as long as the content ratio is within the above-mentioned range.

[0178] (Experiment 10)

[0179] A soft magnetic alloy film was prepared by the same method as in Experiment 6, except that the heat treatment conditions in the samples of Example 89 and Comparative Example 25 were set to the conditions shown in Table 10. The spacing between (110) planes of the soft magnetic alloy was calculated in the same manner as in Experiment 5, except that the evaluation was the same as in Experiment 6. The results are shown in Table 10.

[0180]

[0181] According to Table 10, it can be confirmed that when the holding temperature is too high, the (110) plane spacing expansion value becomes smaller and the saturation magnetic flux density increases, but there is a tendency for the grain size to become larger and the coercive force to become larger. It can be confirmed that when the holding temperature is too low, the grain size is small and the coercive force is small, but the plane spacing expansion is large, and even if the holding time is extended, sufficient saturation magnetic flux density cannot be obtained. On the other hand, it can be confirmed that if the holding time is extended at an appropriate temperature, the plane spacing expansion becomes smaller, the saturation magnetic flux density increases, and the increase in the grain size and the accompanying increase in coercive force are extremely small. Furthermore, by performing a first-stage heat treatment at an appropriate temperature and then a second-stage long-term heat treatment at a relatively low temperature, it is possible to obtain fine Fe-based nanocrystals with small plane spacing expansion, and it is possible to obtain a soft magnetic alloy with small coercive force and high saturation magnetic flux density.

Claims

1. A soft magnetic alloy, wherein The soft magnetic alloy has a composition formula (Fe (1-α) A α ) (1-m-x-y) M m X x Y y express, M is at least one selected from Zr and Hf, X is at least one selected from Ni, Mn, Cu, Co, Al and Ge, Y is at least one selected from B, P and Si, A is at least one selected from Ti, V, Cr, Zn, Mg, Sn, Bi, O, N, S and rare earth elements, m, x, y and α satisfy the following relationship: 0.070≤m≤0.120、 0.001≤x≤0.030、 0≤y≤0.010、 0≤α≤0.100， The soft magnetic alloy has Fe-based nanocrystals having an average crystal grain size of 30 nm or less.

2. The soft magnetic alloy according to claim 1, wherein y satisfies the relationship 0≤y≤0.

005.

3. The soft magnetic alloy according to claim 1 or 2, wherein X is at least one selected from Ni and Mn.

4. The soft magnetic alloy according to claim 1 or 2, wherein The Fe-based nanocrystals have a bcc structure, and the expansion value of the (110) plane spacing of the Fe-based nanocrystals relative to the (110) plane spacing of pure iron having a bcc structure is 0.020 angstroms or less.

5. A magnetic core, wherein: The invention is composed of the soft magnetic alloy according to any one of claims 1 to 4.

6. A magnetic component, wherein: A soft magnetic alloy according to any one of claims 1 to 4 or a magnetic core according to claim 5.

Images