JP6080094B2 - Winding core and magnetic component using the same - Google Patents

Description

  The present invention relates to a wound magnetic core suitable for a distribution transformer, a high-frequency transformer, a saturable reactor, a magnetic switch, and the like.

  Soft magnetic materials used for various reactors, choke coils, pulse power magnetic components, transformers, motor or generator magnetic cores, current sensors, magnetic sensors, antenna cores, electromagnetic wave absorbing sheets, etc. There are crystalline soft magnetic alloys, Fe-based amorphous soft magnetic alloys and Fe-based nanocrystalline soft magnetic alloys. Silicon steel is inexpensive and has a high magnetic flux density, but at high frequencies it has a large loss and is difficult to thin. Since ferrite has a low saturation magnetic flux density, magnetic saturation is likely to occur in high power applications where the operating magnetic flux density is large. Co-based amorphous alloys are expensive and have a low saturation magnetic flux density of 1 T or less, so the parts become large when used for high power, and the loss increases with time due to thermal instability. . The Fe-based amorphous soft magnetic alloy has a saturation magnetic flux density as low as about 1.5 T and cannot be said to have a sufficiently low coercive force. Therefore, the following Fe-based nanocrystalline soft magnetic alloy is promising.

Patent Document 1 _discloses a composition formula: Fe _100-xyz Cu _x B _y X _z (where X is at least one element selected from the group consisting of Si, S, C, P, Al, Ge, Ga, and Be). X, y, and z are each atomic% and are represented by the following conditions: 0.1 ≦ x ≦ 3.0, 10 ≦ y ≦ 20, 0 <z ≦ 10.0, and 10 <y + z ≦ 24. Fe-based nanocrystalline soft particles with a high saturation magnetic flux density of 1.7 T or more and a low coercive force, with at least a part of the structure having 30% by volume or more of crystal grains with a crystal grain size of 60 nm or less in the amorphous matrix. A magnetic alloy is disclosed. This Fe-based nanocrystalline soft magnetic alloy is an initial ultra-microcrystalline alloy in which fine crystal grains with an average particle size of 30 nm or less are dispersed in an amorphous material at a rate of less than 30% by quenching the molten Fe-based alloy. Is produced by subjecting this initial ultrafine crystal alloy to heat treatment at high temperature for a short time or at low temperature for a long time.

Patent Document 2 discloses a composition formula: Fe _100-xy A _x X _y (where A is Cu and / or Au, and X is composed of B, Si, S, C, P, Al, Ge, Ga, and Be). And at least one element selected from the group, wherein x and y are atomic%, each having a composition satisfying the conditions of 0 <x ≦ 5 and 10 ≦ y ≦ 24) And having a parent phase structure in which crystal grains having an average grain size of 60 nm or less are dispersed in an amorphous material at a depth of more than 120 nm from the surface of the ribbon, and 120% from the surface of the ribbon. An Fe-based nanocrystalline soft magnetic alloy ribbon having an amorphous layer at a depth of less than nm is disclosed. In this alloy ribbon, a nanocrystal layer is formed on the outermost surface of the ribbon, an amorphous layer is formed inside the nanocrystal layer, and coarse crystal grains are formed between the amorphous layer and the parent phase. It is described that a layer can be formed. The crystal grain size of the coarse crystal grain layer is desirably less than twice the average crystal grain size of the parent phase.

  These alloy ribbons are generally produced by jetting molten alloy heated to a temperature higher than the liquidus temperature from a nozzle onto a copper alloy cooling roll rotating at high speed, and rapidly cooling and solidifying. In this liquid quenching method, there is a twin roll method in which the cooling rolls are brought into close contact with both sides, but in general, it is manufactured using a single roll method in which only one side is brought into contact. An alloy ribbon manufactured by the one-roll method has a roll contact surface that rapidly solidifies in contact with a cooling roll and a free surface on the opposite side.

  The alloy ribbon has a very thin plate thickness (several tens to several hundreds of μm), and the wound magnetic core wound with it has a stress that remains after bending and exhibits magnetic properties different from those of a single plate sample. It has been known. For this reason, ingenuity has also been added to the method of winding the ribbon. For example, in the wound magnetic core of Patent Document 3, the amorphous alloy ribbon is wound with a highly smooth surface (roll contact surface) on the inside, and the free surface having irregularities is located on the outside, so that the compressive stress applied to the inside is reduced. Get smaller. As a result, the anisotropy associated with the stress is reduced and the iron loss can be reduced. However, due to the establishment of manufacturing equipment and manufacturing methods, the unevenness of the free surface seen in the past has almost disappeared, and there is almost no noticeable difference between the surface roughness (Ra) of the free surface and the roll surface. Absent.

  According to Patent Document 4, contrary to Patent Document 3, iron loss can be reduced by winding the roll contact surface outward. This is because the rapid cooling rate at the time of manufacturing the ribbon varies in the depth direction of the ribbon, resulting in a gradient in the density in the depth direction. This is because a compressive force is generated due to the difference and a 90 ° domain wall is generated, so that the magnetic domains are subdivided and eddy currents are reduced. However, almost no difference in the density gradient in the depth direction is observed in the amorphous alloy ribbon, and the difference in characteristics as described in this document cannot be confirmed.

International Publication WO2007 / 032531 International Publication WO2008 / 114605 Japanese Patent Publication No.58-41649 Japanese Patent No. 2817965

  Conventionally, there has been a study of a wound core using an amorphous alloy ribbon (Fe-based amorphous soft magnetic alloy) as in Patent Documents 3 and 4, but it has initial ultrafine crystal grains as in Patent Documents 1 and 2. A wound core using a thin ribbon has not been studied. For example, this Fe-based nanocrystalline soft magnetic alloy is promising as a magnetic component such as a transformer, a saturable reactor, and a magnetic switch because it exhibits a high saturation magnetic flux density and a low coercive force. Small iron loss and exciting power (apparent power) are desired.

  In view of the above, the object of the present invention is to improve the crystallization properties of the Fe-based nanocrystalline soft magnetic alloy ribbons of Patent Documents 1 and 2, and for winding cores using this alloy ribbon, The purpose is to provide a wound core having low iron loss and low excitation power by elucidating the influence of the difference on magnetic characteristics. Another object of the present invention is to provide a highly efficient and low noise magnetic component using the wound magnetic core.

The present invention is a general formula: Fe100-x-y-AzByXz (where A is Cu and / or Au, and X is at least one selected from Si, S, C, P, Al, Ge, Ga and Be) And x, y, and z are numbers in atomic% that satisfy the conditions of 0 <x ≦ 5, 4 ≦ y ≦ 22, 0 ≦ z ≦ 15, and x + y + z ≦ 25, respectively. It has a composition, a ribbon thickness of 16 to 25 μm, a structure in which fine crystal grains having an average grain size of 60 nm or less are dispersed in an amorphous matrix at a ratio of 30% by volume or more, and 2 from the surface of the roll contact surface. A wound magnetic core comprising a Fe-based nanocrystalline soft magnetic alloy ribbon in which a layer containing coarse crystal grains having an average grain size of at least twice the average grain size of the fine crystal grains is formed in a range of .9 μm or less; The roll contact surface of the Fe-based nanocrystalline soft magnetic alloy ribbon is wound outward It is a wound magnetic core characterized by being. Here, the layer containing coarse crystal grains can be formed on the free surface side, but the free surface side has a higher number density of fine crystal grains, and the depth of the coarse crystal grain layer is larger than that on the roll contact surface side. Also shallow. Therefore, it is specified that the surface formed deeper than the surface having the coarse crystal grain layer is the roll contact surface.

  Another aspect of the present invention is a magnetic component using the wound magnetic core. High-efficiency, low-noise magnetic parts can be realized.

According to the present invention, since the formation depth of the layer containing coarse crystal grains of the Fe-based nanocrystalline soft magnetic alloy ribbon is suppressed, stable high saturation magnetic flux density and low coercive force can be expressed. And it rolls by making the roll contact surface which has this coarse crystal grain layer outside, and it becomes a wound core which reduced iron loss and reduced exciting power (apparent power).
Therefore, by using this wound magnetic core, it is possible to provide a magnetic component with high efficiency because it has a high saturation magnetic flux density and low iron loss and low noise due to low excitation power.

(A) Schematic showing a cross section near the roll contact surface of an initial ultrafine crystal alloy manufactured using a cooling roll with a low cooling capacity, (b) Initial ultrafine manufactured using a cooling roll with a high cooling capacity It is the schematic which shows the cross section of the roll contact surface vicinity of a crystal alloy. It is a graph which shows the DSC curve which has the 1st exothermic peak by nanocrystallization of an amorphous mother phase, and the 3rd exothermic peak by compound precipitation. It is a graph which shows the DSC curve which has the 2nd exothermic peak by the production | generation of a coarse crystal grain. (A) The graph which shows a BH curve when a coarse crystal grain layer is thin, (b) The graph which shows a BH curve when a coarse crystal grain layer is thick. (A) Schematic showing a method for obtaining the total calorific value of the first exothermic peak and the second exothermic peak in the DSC curve, (b) Schematic showing a method for obtaining the calorific value of the second exothermic peak in the DSC curve It is. It is a graph which shows the cooling rate distribution of the thickness direction of a ribbon in the case where the inlet temperature of cooling water is low and high. It is the schematic diagram which showed the change of the initial ultrafine crystal grain before and behind heat processing for demonstrating this invention. It is a schematic diagram which shows the relationship of each residual stress and magnetostriction of the example of this invention which wound the roll contact surface outside (b) and the comparative example which wound the roll contact surface inside. (A) TEM photograph showing the cross section near the roll contact surface of the nanocrystalline soft magnetic alloy ribbon in sample 1-8, (b) Cross section near the roll contact surface of the nanocrystalline soft magnetic alloy ribbon in sample 1-7 It is a TEM photograph shown. 6 is a graph showing the heat treatment temperature dependence of the core loss (P), hysteresis loss (Ph), eddy current loss (Pe), and excitation power (S) of the wound core of the present invention in which the roll contact surface is wound outward. 6 is a graph showing the heat treatment temperature dependence of iron loss (P), hysteresis loss (Ph), eddy current loss (Pe), and excitation power (S) of a wound core of a comparative example in which the roll contact surface is wound inward. 6 is a graph showing the heat treatment temperature dependence of the coercive force (Hc), residual magnetic flux density (Br), and magnetic flux density (B ₈₀ ) of the wound core of the present invention example in which the roll contact surface is wound outward. 6 is a graph showing the heat treatment temperature dependence of the coercive force (Hc), residual magnetic flux density (Br), and magnetic flux density (B ₈₀ ) of a wound core of a comparative example in which the roll contact surface is wound inward. It is a graph which shows the heat treatment temperature dependence of the iron loss (P) and excitation electric power (S) in 1.55T and 50Hz of the winding core B. It is a graph which shows the heat treatment temperature dependence of the iron loss (P) and excitation electric power (S) in 1.55T and 50Hz of the winding core C. 4 is a graph showing a relationship between a winding inner diameter and an iron loss (P) when the roll contact surface is wound outward and when wound inside. 6 is a graph showing a relationship between a winding inner diameter and excitation power (S) when the roll contact surface is wound outward and when wound inside.

  First, the Fe-based nanocrystalline soft magnetic alloy ribbon (hereinafter sometimes referred to as nanocrystalline soft magnetic alloy ribbon or simply alloy ribbon) used in the wound core of the present invention will be described in detail below. As used herein, the term “initial ultrafine crystal grains” means crystal nuclei that have precipitated in an amorphous alloy formed by rapidly cooling a molten alloy and grow into fine crystal grains by heat treatment. “Microcrystalline grains” mean microcrystalline grains grown from the initial ultrafine crystalline grains by heat treatment. The amorphous alloy is referred to as an “initial ultrafine crystal alloy” because initial ultrafine crystal grains that become the nuclei of fine crystal grains are precipitated.

[1] Crystallization and exothermic peak of initial microcrystalline alloy Fig. 1 (a) shows the microstructure of the contact surface of the initial microcrystalline alloy near the cooling roll when a cooling roll with low cooling capacity (low cooling efficiency) is used. FIG. 1 (b) shows the structure in the vicinity of the cooling roll contact surface of the initial microcrystalline alloy when a cooling roll having a high cooling capacity (high cooling efficiency) is used. At a position distant from the roll surface, Cu clusters are diffused by the diffusion of Cu atoms in the cooling process to form Cu clusters (regular lattices of several nm), and the initial ultrafine crystal grains are precipitated with the Cu clusters as nuclei. In the case of a chill roll with low laboratory-level cooling capacity, the initial ultrafine crystal grains are also deposited in the area near the roll contact surface and are present in a relatively high density without being biased in the cross-sectional direction of the alloy, thereby suppressing coarsening. In addition, since the Fe content of the remaining amorphous phase is greatly reduced, the compound precipitation temperature T _X3 is high. On the other hand, in the case of a mass production cooling roll having a high cooling capacity, the number density of the initial ultrafine crystal grains is extremely low because Cu diffusion is suppressed near the roll contact surface and Cu clusters are not easily formed. Although this tendency is also on the free surface side, it appears more remarkably on the roll contact surface side.

When the initial ultrafine crystal alloy is heat-treated, the growth rate from the initial ultrafine crystal grains to the fine crystal grains (nanocrystallization) is slow, so that the temperature of 100 ° C or higher from the nanocrystallization start temperature T _X1 to the compound precipitation temperature T _X3 Over a range, nanocrystallization proceeds slowly. As a result, as shown in FIG. 2, the DSC curve shows a broad first value indicating the exotherm due to nanocrystallization between the nanocrystallization initiation temperature T _X1 and the compound precipitation temperature T _X3 between 300 ° C. and 500 ° C. One exothermic peak P1 appears.

  In the nanocrystallization process, it was thought that the residual amorphous phase was stabilized because Fe was deprived and the boron concentration was increased, thereby suppressing the growth of crystal grains. However, when the initial microcrystalline alloy is continuously produced, a second exothermic peak P2 having a narrow temperature range of about 400 to 460 ° C., for example, appears in the middle of the first exothermic peak P1 as shown in FIG. is there. This second exothermic peak P2 was found to be generated by heat generation accompanying crystallization of the amorphous phase in the region in the vicinity of the roll contact surface where there are few initial ultrafine crystal grains (initial ultrafine crystal grain deficient region). In the initial ultrafine crystal grain-deficient region, crystallization of the amorphous phase occurs rapidly by heat treatment, so that not only does the crystal grain grow coarser than the microcrystal grains of the parent phase, but the initial ultrafine crystal grain-deficient region is deep. Thus, it was found that a deep coarse crystal grain layer was formed, the effective magnetocrystalline anisotropy was increased, and the magnetic saturation was deteriorated.

[2] Influence of Coarse Grain Layer on Soft Magnetic Properties This nanocrystalline soft magnetic alloy has a composite structure having a nanocrystalline layer, an amorphous layer, and a nanocrystalline layer in order from the surface. Organization is not essential. Note that the coarse crystal grain layer can be said to have coarse crystal grains precipitated in the amorphous layer, so the presence of the amorphous layer may be unclear. As used herein, the term “layer” is not divided by a clear boundary, but means a range in the thickness direction that satisfies a predetermined condition. For example, the nanocrystal layer is a very thin range where fine crystal grains of about 20 nm are deposited, and the coarse crystal grain layer is a coarse crystal having an average grain size that is at least twice the average grain size of the microcrystal grains in the parent phase. It is a range in the thickness direction including grains. Specifically, the depth from the surface of the coarse crystal grain layer is 2.9 μm or less, preferably 2.7 μm or less, more preferably 2.5 μm or less (including 0). Incidentally, the coarse crystal grain layer on the free surface side is smaller than the roll contact surface side, and the depth is within 0.5 μm at most.

When the coarse grain layer is thin, the magnetic flux density B ₈₀ at a low magnetic field (80 A / m) and the magnetic flux density B at a high magnetic field (8000 A / m) as shown in the BH curve in Fig. 4 (a). The ratio B ₈₀ / B ₈₀₀₀ to ₈₀₀₀ (approximately the same as the saturation magnetic flux density B _s ) is large, and the soft magnetic characteristics are good. On the other hand, when the coarse crystal grain layer is thick, B ₈₀ / B ₈₀₀₀ is small as shown in the BH curve shown in FIG. 4 (b). In general, the larger B ₈₀ / B ₈₀₀₀ is, the better the saturation magnetization characteristic is. B ₈₀ / B ₈₀₀₀ is preferably 0.85 or more, and more preferably 0.88 or more.

The coercive force H _c depends not only on the average crystal grain size of the matrix structure but also on the ratio of the second exothermic peak. As described above, in the initial microcrystalline alloy produced using a cooling roll having a high cooling capacity, the rapid cooling effect reaches a deeper part of the alloy, so that the initial microcrystalline grain deficient region is wide and the coercive force H _c is increased. .

In order to satisfy both the high B ₈₀ / B ₈₀₀₀ and the low coercive force H _c , it is necessary to obtain an initial ultrafine crystal alloy in which the formation of a coarse grain layer is suppressed. In the DSC curve obtained by heat-treating such an initial microcrystalline alloy, the ratio of the second exothermic peak with respect to the total heat generation amount of nanocrystallization is small. The total calorific value of the nanocrystallization is the total calorific value of the first exothermic peak and the second exothermic peak.The DSC curve shown in Fig. 5 (a) is a straight line that passes through the curve from T _X1 to T _X3. This corresponds to the area S of the enclosed region. The calorific value of the second exothermic peak P2, as shown in FIG. 5 (b), is a region surrounded by a curve from the start temperature T _X2S to the end temperature T _X2E of the second exothermic peak P2 and a straight line passing through both points. It corresponds to the area S _2. The calorific value of the first exothermic peak P1 corresponds to the area S ₁ (= S−S ₂ ). Therefore, the ratio of the second exothermic peak with respect to the total heat generation amount of nanocrystallization is obtained by S ₂ / S.

Specifically, when the ratio of the calorific value of the second exothermic peak P2 to the total calorific value of nanocrystallization is 3% or less, B ₈₀ / B ₈₀₀₀ is 0.85 or more, and the ratio of the second exothermic peak decreases. As you do, B ₈₀ / B ₈₀₀₀ increases. When the ratio of the second exothermic peak is 1.5% or less, the coercive force _Hc is sufficiently small. For this reason, the ratio of the second exothermic peak is preferably 0 to 3%, more preferably 0 to 1.5%, and particularly preferably 0 to 1.3%.

  One of the factors that influence the size of the second exothermic peak generated with the formation of coarse crystal grains is the cooling capacity of the cooling roll. The cooling capacity is determined by the surface temperature and peripheral speed of the cooling roll, the peeling temperature from the cooling roll, and the like. In general, if the cooling capacity is too high, the region where the initial ultrafine crystal grains are insufficient increases, and coarse crystal grains increase due to heat treatment. In addition, since the second exothermic peak is expressed by continuous operation for a long time, it is estimated that the surface temperature of the cooling roll changes during the continuous operation for a long time. Therefore, in addition to the peripheral speed and peeling temperature of the cooling roll, it is necessary to adjust the temperature of the cooling water that determines the surface temperature of the cooling roll.

[3] magnetic alloys
(1) Composition The nanocrystalline magnetic alloy of the present invention has a general formula: Fe _100-xyz A _x B _y X _z (where A is Cu and / or Au, and X is Si, S, C, P, Al , Ge, Ga, and Be, and x, y, and z are atomic percentages of 0 <x ≦ 5, 4 ≦ y ≦ 22, 0 ≦ z ≦ 15, and x + y + z ≦ 25, respectively. It is a number that satisfies the condition).

  In order to achieve both good soft magnetic properties and high saturation magnetic flux density Bs, this alloy is based on the following Fe-B-Si system, which can stably produce an amorphous phase even with high Fe content. Contains nucleation element A. Specifically, Cu and / or Au, which is insoluble in Fe, is Fe-B-Si alloy with Fe content of 88 atomic% or less, which can stably obtain a ribbon with the amorphous phase as the main phase. Add (nucleating element A). A is Cu and / or Au, and has the effect of precipitating initial ultrafine crystal grains and growing them uniformly into fine crystal grains by subsequent heat treatment.

  If the amount x of element A exceeds 5 atomic%, a ribbon having an amorphous phase as a main phase obtained by rapid cooling of the molten metal becomes extremely brittle, which is not preferable. The amount x of element A is 0.3 to 2 atomic%, preferably 0.5 to 1.6 atomic%, more preferably 1 to 1.6 atomic%, and particularly preferably 1.2 to 1.6 atomic%. As element A, Cu is preferable in terms of cost.

  B (boron) is an element that promotes the formation of an amorphous phase. If B is less than 4 atomic%, it is difficult to obtain a ribbon having an amorphous phase as a main phase, and if it exceeds 22 atomic%, the saturation magnetic flux density is remarkably lowered. The B amount y is preferably 10 to 20 atomic%, more preferably 12 to 18 atomic%, and particularly preferably 12 to 16 atomic%.

  The X element is at least one element selected from Si, S, C, P, Al, Ge, Ga, and Be, and has an effect of stabilizing the amorphous phase and improving magnetic properties. In particular, when X is Si, the temperature at which the Fe-B compound or Fe-P compound with large crystal magnetic anisotropy precipitates increases, so that the heat treatment temperature can be increased and high temperature heat treatment can be performed. The ratio is increased, Bs is increased, the squareness of the BH curve is improved, and alteration or discoloration of the ribbon surface can be suppressed, which is preferable. The lower limit of the amount z of X element may be 0 atomic%, but if it is 1 atomic% or more, an oxide layer of X element is formed on the surface of the ribbon and the internal oxidation can be sufficiently suppressed. Further, when the X element amount z exceeds 15 atomic%, Bs is remarkably lowered, which is not preferable. The X element amount z is preferably 2 to 13 atomic%, more preferably 3 to 10 atomic%, and particularly preferably 4 to 7 atomic%. Si is preferable as the X element.

  Of the X elements, P is an element that improves the ability to form an amorphous phase, and suppresses the growth of microcrystalline grains and suppresses segregation of B into the oxide film. Therefore, P is preferable for realizing high toughness, high Bs, and good soft magnetic properties. By containing P, for example, even when a soft magnetic alloy ribbon is wound around a round bar having a radius of 1 mm, cracks do not occur. This effect can be obtained regardless of the heating rate of the nanocrystallization heat treatment. Other elements C, Ge, Ga and Be can also be used as the X element. Magnetostriction and magnetic properties can be adjusted by the inclusion of these elements. X element is also easily segregated on the surface and is effective in forming a strong oxide film.

  The B amount y needs to be at least 4 atomic% in order to form Cu clusters in the amorphous phase, but if it is less than 10 atomic%, the total amount y + z of B and X elements (Si, P) is 15 ≦ y + z ≦ 25. Within this range, the same ribbon and soft magnetic characteristics as in the case of 10 atomic% or more can be obtained. At this time, when y + z is less than 15 atomic%, it is difficult to produce an amorphous ribbon of an amorphous main phase.

  A part of Fe may be substituted with at least one element selected from Ni, Mn, Co, V, Cr, Ti, Zr, Nb, Mo, Hf, Ta and W. These element substitution amounts are preferably 0.01 to 10 atomic%, more preferably 0.01 to 3 atomic%, and particularly preferably 0.01 to 1.5 atomic%. Among these elements, Ni, Mn, Co, V and Cr have the effect of moving the region with a high B concentration to the surface side, and the microstructure is similar to the structure close to the internal matrix from the region close to the surface. It becomes a structure and improves the soft magnetic properties (permeability, coercive force, etc.) of the soft magnetic alloy ribbon.

In particular, when a part of Fe is replaced with Co or Ni that is dissolved in Fe together with A element, the amount of A element that can be added can be increased, the refinement of crystal structure is promoted, and soft magnetic properties are improved. The The Ni substitution amount is preferably 0.1 to 2 atom%, more preferably 0.5 to 1 atom%. When the Ni substitution amount is less than 0.1 atomic%, the effect of improving the handling property is insufficient, and when it exceeds 2 atomic%, B _s , B ₈₀ and H _c decrease.

Similarly, Ti, Zr, Nb, Mo, Hf, Ta, and W, together with the A element and metalloid element, preferentially enter the amorphous phase remaining after the heat treatment, contributing to the improvement of the soft magnetic properties. On the other hand, if there are too many of these elements having a large atomic weight, the Fe content per unit weight is lowered, leading to a decrease in magnetic flux density, which is not preferable. The total amount of these elements is preferably 3 atomic% or less. Particularly in the case of Nb and Zr, the total content is preferably 2.5 atomic percent or less, and more preferably 1.5 atomic percent or less. In the case of Ta and Hf, the total content is preferably 1.5 atomic percent or less, and more preferably 0.8 atomic percent or less.
The alloy of the present invention may contain inevitable impurities such as O and N.

(2) Matrix structure After heat treatment, the matrix is a structure in which microcrystal grains with a body-centered cubic (bcc) structure with an average grain size of 60 nm or less are dispersed in the amorphous phase at a volume fraction of 30% or more. Have If the average grain size of the fine crystal grains exceeds 60 nm, the soft magnetic properties are undesirably lowered. A volume fraction of fine crystal grains of less than 30% is not preferable because the amorphous ratio is too high, the saturation magnetic flux density is low, and the magnetostriction is increased. The average grain size of the fine crystal grains after the heat treatment is more preferably 40 nm or less, and particularly preferably 30 nm or less. Further, the volume fraction of the fine crystal grains after the heat treatment is preferably 40% or more, more preferably 50% or more. With an average particle size of 60 nm or less and a volume fraction of 30% or more, an alloy ribbon having lower magnetostriction and superior soft magnetism than an Fe-based amorphous alloy can be obtained. The Fe-based amorphous alloy ribbon with the same composition has a relatively large magnetostriction due to the magnetovolume effect, but the Fe-based nanocrystalline soft magnetic alloy of the present invention in which fine crystal grains mainly composed of bcc-Fe are dispersed is magnetic volume. The magnetostriction caused by the effect is much smaller and the noise reduction effect is great.

[4] Manufacturing method
(1) Alloy melt The alloy melt has the general formula: Fe _100-xyz A _x B _y X _z (where A is Cu and / or Au, and X is Si, S, C, P, Al, Ge, Ga) And at least one element selected from Be, and x, y, and z are atomic percentages that satisfy the conditions of 0 <x ≦ 5, 4 ≦ y ≦ 22, 0 ≦ z ≦ 15, and x + y + z ≦ 25, respectively. It has a composition represented by. Taking the case of using Cu as the element A as an example, the manufacturing method will be described.

(2) Quenching of molten metal Quenching of molten alloy can be performed by a single roll method. The molten metal temperature is preferably 50 to 300 ° C. higher than the melting point of the alloy. For example, when manufacturing a ribbon having a thickness of several tens of μm on which initial ultrafine crystal grains are precipitated, a molten roll of 1200 to 1350 ° C. is cooled from the nozzle It is preferable to eject it upward. The atmosphere in the single roll method is air or an inert gas (Ar, nitrogen, etc.) when the alloy does not contain an active metal, and an inert gas (Ar, He, nitrogen, etc.) It is a vacuum. In order to form an oxide film on the surface, it is preferable to quench the molten metal in an oxygen-containing atmosphere (for example, air).

The formation of initial ultrafine grains is closely related to the cooling rate and time of the alloy ribbon. During the cooling process, Cu agglomerates by thermal diffusion to form clusters, forming initial ultrafine crystal grains. Therefore, in the surface region where the cooling rate is high, thermal diffusion hardly occurs, and initial ultrafine crystal grains serving as nuclei are hardly generated, so that the crystal grains formed after the heat treatment become coarse. For this reason, it is important to control the volume fraction (number density, the same applies hereinafter) of the initial ultrafine crystal grains for miniaturization. One of the means for controlling the volume fraction of the initial ultrafine crystal grains is the control of the peripheral speed of the cooling roll. When the peripheral speed of the cooling roll increases, the volume fraction of the initial ultrafine crystal grains decreases, and increases when it decreases. The peripheral speed of the cooling roll is preferably 15 to 50 m / s, more preferably 20 to 40 m / s, and 25 to 35.
m / s is most preferred. As the material of the cooling roll, pure copper having high thermal conductivity or a copper alloy such as Cu—Be, Cu—Cr, Cu—Zr, Cu—Zr—Cr, Cu—Ni—Si is suitable.

  In the case of mass production, or when producing a thick and / or wide ribbon, the cooling roll is preferably water-cooled. Water cooling of the cooling roll has a great influence on the volume fraction of the initial ultrafine crystal grains. In order to control the volume fraction and soft magnetism of ultrafine crystal grains, it is effective to maintain the cooling capacity of the cooling roll (which may be referred to as a cooling rate). In a mass production line, the cooling capacity of the cooling roll has a correlation with the temperature of the cooling water, and it is effective to keep the cooling water at a predetermined temperature or higher.

  FIG. 6 shows the cooling rate distribution in the thickness direction of the ribbon. The cooling rate of the ribbon is fastest at the part in contact with the surface of the cooling roll, decreases as it goes inward, and is slightly higher due to air cooling again on the free (free) surface. As shown in curve B, since the cooling rate is high when the cooling water inlet temperature is low, there is a deep initial ultrafine crystal grain-deficient region (the number density of the initial ultrafine crystal grains is low and the volume fraction is insufficient). As a result, the soft magnetic properties of the nanocrystalline soft magnetic alloy deteriorate. On the other hand, since the cooling rate is low when the inlet temperature of the cooling water is high as shown by the curve A, a shallow initial ultrafine crystal grain deficient region is formed, and the nanocrystalline soft magnetic alloy has excellent soft magnetic properties. By adjusting the cooling water inlet temperature in this way, the cooling rate of the ribbon can be controlled, the initial ultrafine crystal grain deficiency region is reduced, and the soft magnetic properties of the resulting nanocrystalline soft magnetic alloy are improved. be able to. Although depending on the alloy composition and production line conditions, the inlet temperature of the cooling water is preferably 30 to 70 ° C, more preferably 40 to 70 ° C, and particularly preferably 50 to 70 ° C. The outlet temperature of the cooling water is preferably 40 to 80 ° C, more preferably 50 to 80 ° C.

(3) Peeling temperature The alloy ribbon is peeled from the cooling roll by blowing an inert gas (nitrogen, etc.) from the nozzle between the rapidly cooled alloy ribbon and the cooling roll. It is thought that the peeling temperature of the alloy ribbon at this time also affects the volume fraction of the initial ultrafine crystal grains. The stripping temperature of the ribbon can be adjusted by changing the position (peeling position) of the nozzle that sprays the inert gas. The peeling temperature is 170 to 350 ° C, preferably 200 to 340 ° C, and more preferably 250 to 330 ° C. When the peeling temperature is less than 170 ° C., rapid cooling progresses and the alloy structure becomes almost amorphous, Cu aggregation, Cu cluster formation, and precipitation of initial ultrafine crystal grains do not occur, and the crystal grains after heat treatment are coarse. This is not preferable. When the cooling rate of the above-described cooling roll is appropriate, the surface area of the ribbon is reduced in Cu content due to rapid cooling and the initial ultrafine crystal grains are not generated, but the cooling rate is relatively slow internally, and the heterogeneous nucleation site As the number density of Cu clusters behaving as is high, the initial ultrafine crystal grains are distributed more than the surface area, and the initial ultrafine crystal grains are generated homogeneously. As a result, a layer having a higher B concentration (a higher ratio of B to Fe) than the inner matrix is formed in the surface region (depth 30 to 130 nm). Due to the high B concentration amorphous layer in the vicinity of the surface, the initial ultracrystalline alloy ribbon exhibits relatively good toughness. When the peeling temperature is higher than 350 ° C., crystallization proceeds excessively, and a high B concentration amorphous layer is not formed in the vicinity of the surface, so that it is difficult to obtain sufficient toughness.

  Since the inside of the peeled initial microcrystalline alloy ribbon is still relatively hot, the initial ultracrystalline alloy ribbon is sufficiently cooled before winding to prevent further crystallization. For example, an inert gas (nitrogen or the like) is sprayed on the peeled initial ultrafine crystal alloy ribbon, and after cooling to substantially room temperature, winding is performed.

(4) The ribbon of the initial ultrafine crystal alloy The ribbon of the initial ultrafine crystal alloy consists of 5-30% by volume of initial ultrafine crystal grains with an average grain size of 30 nm or less in the amorphous matrix. Has a distributed organization. When the average grain size of the initial ultrafine crystal grains exceeds 30 nm, the heat treatment described below is not preferable because the crystal grains become too coarse and the soft magnetic properties deteriorate. In order to obtain excellent soft magnetic properties, the average grain size of the initial ultrafine crystal grains is preferably 25 nm or less, more preferably 20 nm or less, most preferably 10 nm or less, and particularly preferably 5 nm or less. The average grain size of the initial ultrafine crystal grains is preferably 1 nm or more, and more preferably 2 nm or more. The volume fraction of the initial ultrafine crystal grains in the initial ultracrystalline alloy ribbon is greater than 0, preferably in the range of 5 to 30%. If the volume fraction of the initial ultrafine crystal grains exceeds 30%, the average grain size of the initial ultrafine crystal grains tends to exceed 30 nm, and the alloy ribbon does not have sufficient toughness. Handling becomes difficult. On the other hand, if the initial ultrafine crystal grains do not exist (if they are completely amorphous), the crystal grains become coarse due to heat treatment, which is not preferable. The volume fraction of the initial ultrafine crystal grains is preferably 10 to 30%, more preferably 15 to 30%.

  It is preferable that the average distance between the initial ultrafine crystal grains is 50 nm or less because the magnetic anisotropy of the fine crystal grains is averaged and the effective crystal magnetic anisotropy is reduced. When the average distance exceeds 50 nm, the effect of averaging the magnetic anisotropy decreases, the effective crystal magnetic anisotropy increases, and the soft magnetic properties deteriorate.

(5) Heat treatment In order to make the initial ultrafine crystal alloy a soft magnetic alloy having a high magnetic flux density, a more preferable result can be obtained by performing a heat treatment at a temperature higher than the crystallization temperature for a short time. In the region where there are few initial ultrafine crystal grains, the initial ultrafine crystal grains are likely to be coarse because the inter-crystal distance is large, but in the heat treatment at high temperature and short time, the heat treatment is completed during the initial ultrafine crystal grain growth process. Microcrystal grains are difficult to coarsen. The heat treatment for a short time at high temperature can be performed by adjusting the rate of temperature rise, the maximum temperature reached, and the heat treatment time.

The heat treatment temperature needs to be not less than the crystallization start temperature T _{X1 and not} more than the compound precipitation temperature T _X3 . In this invention, it heats up to the said temperature and it cools after holding | maintaining the said time. With relatively short and between the heat treatment time 5-30 minutes including heating time can improve magnetic flux density B ₈₀ in the 80 A / m. A particularly preferable heat treatment temperature is 430 to 470 ° C. The heat treatment time including the temperature raising time is more preferably 10 to 25 minutes. In this range, particularly low coercive force characteristics can be obtained.

(a) Heat treatment atmosphere Although the heat treatment atmosphere may be in the air, the oxygen concentration in the heat treatment atmosphere is preferably 6 to 18%, in order to form an oxide film having a desired layer configuration and ensure insulation between layers, 15% is more preferable, and 9 to 13% is particularly preferable. The heat treatment atmosphere is preferably a mixed gas of an inert gas such as nitrogen, Ar, or helium and oxygen. The dew point of the heat treatment atmosphere is preferably −30 ° C. or lower, more preferably −60 ° C. or lower.

(b) Heat treatment in a magnetic field When imparting good induced magnetic anisotropy to a soft magnetic alloy ribbon by heat treatment in a magnetic field, while the heat treatment temperature is 200 ° C. or higher (preferably 20 minutes or more), It is preferable to apply a magnetic field having a strength sufficient to saturate the soft magnetic alloy ribbon and the magnetic core during at least a part of the period of holding the maximum temperature and cooling. The strength of the magnetic field applied in the width direction of the ribbon (in the case of an annular magnetic core, the height direction) and in the longitudinal direction (in the case of an annular magnetic core, the circumferential direction) vary depending on the shape of the soft magnetic alloy ribbon and magnetic core. It is preferable to apply at least 8000 A / m when applied in the width direction of the ribbon (in the case of an annular magnetic core, the height direction) and at least 400 A / m when applied in the longitudinal direction (circumferential direction in the case of an annular magnetic core) . The magnetic field may be a direct magnetic field, an alternating magnetic field, or a pulsed magnetic field. A soft magnetic alloy ribbon having a DC hysteresis loop with a high squareness ratio or a low squareness ratio can be obtained by heat treatment in a magnetic field. In the case of heat treatment without applying a magnetic field, the soft magnetic alloy ribbon usually has a DC hysteresis loop with a medium squareness ratio.

(6) Surface treatment An oxide film such as SiO ₂ , MgO, and Al ₂ O ₃ may be formed on the nanocrystalline soft magnetic alloy as necessary. When the surface treatment is performed during the heat treatment step, the bond strength of the oxide increases. If necessary, a magnetic core made of a soft magnetic alloy ribbon may be impregnated with resin.

[5] Winding core
(1) Difference in winding method between roll contact surface and free surface First, when a wound core is made of a ribbon, the ribbon is curved. At this time, inside the ribbon, tensile (tensile stress) is generated on the outside and compressive stress is generated on the inside. This stress remains to some extent even after heat treatment and affects the iron loss and excitation power. The alloy ribbon used in the present invention has a roll contact surface side where an initial ultrafine crystal grain-deficient region is likely to be formed and a free surface side where initial fine crystal grains are dispersed at a high density. Therefore, the depth of the coarse crystal grain layer generated after the heat treatment was reduced to stabilize the magnetic properties of the ribbon itself, such as saturation magnetic flux density and coercive force. However, since there is a difference in the amount of initial ultrafine crystal grains generated on the roll contact surface side and the free surface side, in the case of this alloy ribbon, there is a difference in iron loss and excitation power due to the difference in winding method. Conceivable.

FIG. 7 is a schematic diagram showing changes in crystal grains on the roll contact surface side and the free surface side before and after heat treatment in the amorphous matrix. FIG. 8 is a schematic diagram showing the relationship between the residual stress and magnetostriction when (a) the roll contact surface is wound outward and (b) the free surface is wound outward.
As shown in FIG. 7, many initial ultrafine crystal grains are precipitated on the free surface side, and the precipitation on the roll contact surface side tends to be small. When this is heat-treated, since the ultrafine crystal grains are dense on the free surface side, the fine crystal grains exist while the grain growth is suppressed. On the other hand, since the roll contact surface side is dense, the grain growth proceeds and the crystal grains tend to be large, and the amount thereof is also small. If this is replaced with the ratio of the amorphous phase, the remaining ratio of the amorphous (amorphous) phase is reduced due to the generation of a large number of fine crystal grains in the amorphous matrix on the free surface side. On the one side of the roll contact surface, although the depth of the coarse crystal grain layer is suppressed, the number density of the initial ultrafine crystal grains is basically small, so that the fine crystal grains exist coarsely and the amorphous phase remains. The proportion increases. In general, the magnetostriction of the amorphous phase is positive and large, and the magnetostriction of the crystal phase is negative and small. Therefore, the magnetostriction is positive and large on the roll contact surface side with a large amount of residual amorphous phase, and the magnetostriction is small on the free surface side with a small amount of residual amorphous phase.
When such a thin ribbon is wound outward on the roll contact surface side as shown in FIG. 8 (a), tension acts on the roll contact surface side where the magnetostriction is positive and large. The magnetization tends to align in the direction (winding direction). Here, in particular, when heat treatment in a magnetic field is performed so that the magnetization is aligned in the longitudinal direction of the wound magnetic core, the magnetic domains are likely to exist by alternately changing the magnetization direction in a stripe shape in the longitudinal direction across the 180 ° wall. Therefore, magnetic saturation is likely to occur, the iron loss is reduced, and the applied magnetic field required for excitation is reduced, so that the excitation power is also reduced.

  On the other hand, when the roll contact surface is wound inward as shown in FIG. 8B, since the compressive stress remains on the roll contact surface side where the magnetostriction is positive and large, the magnetization is opposite to the case of tension. It becomes difficult to face the longitudinal direction. For this reason, it becomes difficult to saturate, and an improvement in iron loss and excitation power cannot be expected, which is inferior to the case of winding outside. Thus, it has been found that in the alloy ribbon having the difference in the proportion of the fine crystal grains between the roll contact surface side and the free surface side, a difference in magnetic properties appears due to the difference in winding method. As a result, the depth of the coarse crystal grain layer is deeper than that of the other surface, but the iron loss and excitation power are reduced by winding the roll contact surface with the depth suppressed to 2.9 μm or less on the outside.

  Hereinafter, examples of the nanocrystalline soft magnetic alloy ribbon used in the present invention will be described, and then examples of the wound magnetic core will be described. In each example and comparative example of the nanocrystalline soft magnetic alloy ribbon, the peeling temperature of the initial ultracrystalline alloy ribbon, the ratio of the second exothermic peak, and the average grain size and volume fraction of the microcrystalline grains are as follows: Determined by the method.

(1) Measurement of peeling temperature The temperature of the initial ultrafine crystal alloy ribbon when peeling from the cooling roll by nitrogen gas blown from the nozzle is measured with a radiation thermometer (Apiste, model: FSV-7000E), and the peeling temperature is measured. It was.

(2) Measurement of the ratio of the second exothermic peak In the DSC curve shown in Fig. 5 (a) obtained using a differential scanning calorimeter (DSC-8230, manufactured by Rigaku Corporation), the temperatures T _X1 , T _X3 , T _X2S And T _X2E were determined. The heating rate during the measurement was 10 ° C./min. Each temperature was a temperature at the intersection of tangent lines extending from the inflection points of the preceding and following curves. The calorific value of the second exothermic peak relative to the total calorific value (area S shown in Fig. 5 (a)) of the first exothermic peak P1 and the second exothermic peak P2 accompanying nanocrystallization (in Fig. 5 (b) The ratio of the indicated area S ₂ ) was determined by the formula of S ₂ / S.

(3) Measurement of average grain size and volume fraction of microcrystal grains The average grain size of microcrystal grains (the same applies to the initial ultrafine crystal grains) was arbitrarily selected from TEM photographs of each sample (30 or more) ) Were measured by measuring the major axis D _L and minor axis D _S of the fine crystal grains and averaging them according to the formula of Σ (D _L + D _S ) / 2n. In addition, an arbitrary straight line of length Lt is drawn on the TEM photograph of each sample to obtain the total length Lc of the portion where each straight line intersects the fine crystal grains, and the ratio of crystal grains along each straight line L _L = Lc / Lt was calculated. This operation was repeated 5 times, and the volume fraction of fine crystal grains was determined by averaging L _L. Here, the volume fraction V _L = Vc / Vt (Vc is the sum of the volume of the fine crystal grains and Vt is the volume of the sample) is approximated as V _L ≒ Lc ³ / Lt ³ = L _L ³ Treated.

(4) Evaluation of handling properties Handling properties were evaluated according to the following criteria based on the presence or absence of fracture when fixing both ends in the longitudinal direction of a 25 mm wide and 125 mm long strip specimen and twisting it while applying tension. . In actual handling, even if it is twisted 180 °, it does not have to be destroyed.
(Double-circle): Even if it twisted 180 degrees, it did not destroy.
○: It did not break even when twisted by 90 °, but it broke when twisted by 180 °.

Reference example 1
Using a copper alloy cooling roll (peripheral speed: 27 to 32 m / s, cooling water inlet temperature: 25 to 60 ° C., outlet temperature: 33 to 72 ° C.), the composition (atomic%) shown in Table 1 is provided. The molten alloy was rapidly cooled in the air and peeled off from the cooling roll at a ribbon temperature of 250 ° C. to produce an initial ultrafine alloy ribbon having a width of 25 mm and a thickness of 16 to 25 μm. Table 1 shows the alloy composition of each of the initial ultrafine crystal alloy ribbons, the inlet and outlet temperatures of the cooling water, the average particle diameter and volume fraction of the initial ultrafine crystal grains, and the ratio of the second exothermic peak. In the amorphous matrix of these initial ultrafine crystal alloys, initial ultrafine crystal grains having an average grain size of 1 to 5 nm were dispersed at a volume fraction of 3 to 30%. The ratio of the second exothermic peak to the total amount of heat generated by nanocrystallization was determined.

The nanocrystalline soft magnetic alloy ribbon is subjected to a nanocrystallization heat treatment for 15 to 30 minutes at a temperature in the range of 400 to 460 ° C. so as to obtain the maximum B ₈₀ for each initial microcrystalline alloy ribbon. Produced. Average crystal grain size and volume fraction of each nanocrystalline soft magnetic alloy, coarse crystal grain layer [average grain size more than twice the average grain size of microcrystal grains in the parent phase (about 50-100 nm) The depth of the layer containing coarse crystal grains], the coercive force, the magnetic flux density B _{80 at 80} A / m and the magnetic flux density B _{8000 at 8000} A / m, and handling properties (workability such as winding) were measured. The measurement results are shown in Table 2. Each soft magnetic alloy ribbon had a structure in which fine crystal grains having an average particle diameter of 15 to 30 nm were dispersed at a volume fraction of 30 to 50%. In Tables 1 and 2, parentheses are given to samples whose ratio of the second exothermic peak exceeds 3%.

In mass production, it is very important to achieve both soft magnetic properties and handling properties. For example, if the soft magnetic properties (B ₈₀ / B ₈₀₀₀ ) are poor even if twisted to 180 °, the product is inaccurate. Moreover, even if the soft magnetic property is good, if it cannot be twisted to 90 °, handling is difficult and productivity is low. In this example, both soft magnetic characteristics and handling properties were achieved.

From Table 1 and Table 2, when the ratio of the calorific value of the second exothermic peak to the total calorific value of nanocrystallization decreases, the coarse crystal grain layer becomes shallow (the coarse crystal grain decreases), and the second exothermic peak It can be seen that as the ratio increases, B ₈₀ / B ₈₀₀₀ decreases and the magnetic saturation characteristics deteriorate. As shown in Table 1, the ratio of the second exothermic peak corresponds to the depth of the coarse crystal grain layer, and as the coarse crystal grain layer becomes deeper, the ratio of components that are hard to be magnetically saturated increases to 80 A / m. Magnetic flux density at low magnetic field is reduced. When the ratio of the second exothermic peak is 3% or less, the coarse crystal grain layer is less than 3 μm, and the B ₈₀ / B ₈₀₀₀ ratio is almost 85% or more. Since the coercive force H _c reflects the properties of the parent phase having good soft magnetic properties, the value depends on the average crystal grain size of the parent phase. As a general tendency, when the cooling capacity of the roll is increased, the depth of the coarse crystal grain layer is increased and the average crystal grain size of the parent phase is increased. In other words, B ₈₀ tends to decrease and H _c tends to increase, but if the amount of Cu is increased, the initial ultra fine crystal grains of the parent ultra fine crystal alloy can be increased, and H _c can be reduced. I understood that. On the other hand, the second exothermic peak appeared in any sample, but the handling property was not a problem. Even if the ratio of the second exothermic peak is relatively large, the handling characteristics are good.

FIG. 9 shows a cross section in the vicinity of the surface on the roll contact surface side of Sample 1-8 and Sample 1-7 after the heat treatment. The average crystal grain size of the parent phase is about 15 nm, and the depth from the alloy surface of the layer containing coarse crystal grains having an average grain size more than twice this is indicated by double arrows. The white layer on the surface is a carbon-based surface protective film provided for taking a TEM photograph. FIG. 9 (a) shows Sample 1-8. When the ratio of the second exothermic peak was 0.7%, the depth of the coarse crystal grain layer was about 0.7 μm. On the other hand, Fig. 9 (b)
In Sample 1-7, the coarse crystal grain layer was 3.0 μm when the ratio of the second exothermic peak was 3.1%.

  The structure in the vicinity of the surface on the free surface side is a composite structure having a nanocrystal layer, an amorphous layer (a layer containing coarse crystal grains), and a nanocrystal grain layer in order from the surface in the same manner as the roll surface. The composite structure was clearly formed more than the roll contact surface side. The depth of the coarse crystal grain layer on the free surface side is shallow, and the coarse crystal grain layer on the free surface side was observed for samples with a coarse crystal grain layer of less than 3.0 μm as shown in Tables 1 and 2, and the depth of 0 to less than 0.5 μm was observed. That was it.

Reference example 2
The inlet temperature of the cooling water of the roll is set to 35 to 70 ° C, the outlet temperature is controlled to 44 to 82 ° C, and the molten alloy having the composition of Fe _bal. Ni ₁ Cu _1.5 Si ₄ B ₁₄ is cooled at 28 m / s. Was rapidly cooled in the atmosphere at a peripheral speed of, and peeled off from the cooling roll at a ribbon temperature of 250 ° C. to produce an initial ultracrystalline alloy ribbon having a width of 25 mm and a thickness of 20 μm. Table 3 shows the alloy composition of each of the initial ultrafine crystal alloy ribbons, the cooling water inlet temperature and outlet temperature, the average ultrafine crystal grain size and volume fraction, and the ratio of the second exothermic peak. The initial ultrafine crystal grains having an average particle diameter of 2 to 5 nm were dispersed in the amorphous matrix of the initial ultrafine crystal alloy at a volume fraction of 18 to 26%.

Each initial microcrystalline alloy was heated to 430 ° C. in about 15 minutes and then heat-treated for 15 minutes to obtain a nanocrystalline soft magnetic alloy. The average grain size and volume fraction of the fine crystal grains of each nanocrystalline soft magnetic alloy, the depth of the coarse crystal grain layer, the coercive force, B ₈₀ and B ₈₀₀₀ , and handling properties were measured. Table 4 shows the measurement results.

Compared with the reference example 1 alloy containing no Ni shown in Table 1, not deep coarse crystal grain layer even when the ratio of the second exothermic peak is high, the increase in the coercive force H _c is suppressed. It can be seen that the inclusion of Ni suppresses the expansion of the coarse crystal grain layer, making it easy to achieve both handling characteristics and soft magnetic characteristics. From the above, it can be seen that inclusion of an appropriate amount of Ni can reduce the dependence of soft magnetic properties on manufacturing conditions and improve production efficiency.

Reference example 3
A molten alloy having the composition shown in Table 5 in which a part of Fe was replaced with various elements was set in the atmosphere with a cooling water inlet temperature of 50 ° C. at a peripheral speed of a cooling roll of 28 m / s as in Reference Example 1. It was quenched (exit temperature: 59 to 63 ° C.) and peeled from the cooling roll at a ribbon temperature of 250 ° C. to produce an initial ultracrystalline alloy ribbon having a width of 25 mm and a thickness of 20 μm. The initial ultrafine crystal grains having an average grain size of 1 to 10 nm were dispersed at a volume fraction of 5 to 30% in the amorphous matrix of the initial ultrafine crystal alloy. The ratio of the second exothermic peak of each initial microcrystalline alloy was measured while changing the cooling water temperature of the roll. Table 5 shows the alloy composition, the cooling water inlet temperature and outlet temperature, the average grain size and volume fraction of the initial ultrafine crystal grains, and the ratio of the second exothermic peak.

Each initial microcrystalline alloy was subjected to a heat treatment in which the temperature was raised to 430 ° C. in about 15 minutes and then held for 15 minutes to obtain a nanocrystalline soft magnetic alloy. The average grain size and volume fraction of the fine crystal grains of each nanocrystalline soft magnetic alloy, the depth of the coarse crystal grain layer, the coercive force, B ₈₀ and B ₈₀₀₀ , and handling properties were measured. Table 6 shows the measurement results.

  Next, an example of a wound core using the nanocrystalline soft magnetic alloy ribbon described above will be described. In each of the examples and comparative examples, the production of the wound magnetic core and the measurement of the magnetic properties were obtained by the following methods.

(1) Fabrication of wound core The following three types of wound cores were fabricated from a 25 mm wide alloy ribbon using a core winding machine (manufactured by Tobu Seisakusho). Winding core A: outer diameter 19 mm—inner diameter 15 mm, winding core B: outer diameter 26.2 mm—inner diameter 22.2 mm, winding core C: outer diameter 74 mm—inner diameter 70 mm. The winding core A has 20 turns on the primary side, 20 turns on the secondary side, the winding core B has 30 turns on the primary side, 30 turns on the secondary side, and the winding core C has 70 turns on the primary side and 30 turns on the secondary side. It was.

(2) after heat treatment winding of the winding core, the heat treatment furnace (Espec Corp., Model: SSPH-101) by, while a magnetic field of 1500A / m in an N ₂ gas atmosphere the entire period applied to the magnetic path direction, heating The temperature was raised to 400 ° C. at a rate of 8 ° C./min, held for 1 hour, and lowered to 100 ° C. at a rate of temperature drop of 10 ° C./min.

(3) DC magnetic characteristics measurement
A 120 mm single plate sample was measured with a DC magnetization automatic recording device (Metron Giken Co., Ltd.).

(4) Measurement of AC magnetic characteristics AC magnetic characteristics such as iron loss, excitation power, and AC hysteresis loop were measured with an AC magnetometer (manufactured by Toei Industry Co., Ltd., model: TWM-18SR) by sine wave excitation. The eddy current loss (Pe) was obtained by obtaining the hysteresis loss (Ph) from the area surrounded by the DC hysteresis loop and subtracting the hysteresis loss (Ph) from the iron loss (P).
P = Ph + Pe = Ph + (Pae + Pce)
However, Pe is an overcurrent loss, Pae is an abnormal eddy current loss, and Pce is a classic eddy current loss. In this kind of alloy ribbon, the classic eddy current loss Pce is negligibly small.

Example 1
Rolled contact of the wound core A (outer diameter 19 mm-inner diameter 15 mm) using a 25 mm wide and 20 μm thick alloy ribbon with the composition of Fe _bal. Ni ₁ Cu _1.5 Si ₄ B ₁₄ prepared in Sample 2-1 above _. Two types were prepared: an outer winding (invention example) with the surface wound outward, and an inner winding (comparative example) with the roll contact surface wound inward.
For these wound cores, changes in iron loss (P), hysteresis loss (Ph), eddy current loss (Pe), and excitation power (S) at 1.55 T and 50 Hz when the heat treatment temperature was changed were measured. The excitation power S is related to the external magnetic field H required to excite the alloy ribbon to a certain magnetic flux density, and is preferably closely related to the magnitude of noise.

FIG. 10 shows the result of the present invention in which the roll contact surface is wound outward, and FIG. 11 shows the result of a comparative example in which the roll contact surface is wound inward. The eddy current loss (Pe) is both 440 ° C or less and shows an almost constant trend and value regardless of the heat treatment temperature, but the iron loss (P), hysteresis loss (Ph), and excitation power (S) The present invention can be reduced more than the comparative example, and all show the lowest value at 430 ° C. In the case of the comparative example, all of the iron loss (P), hysteresis loss (Ph), and excitation power (S) rise gradually after reaching 440 ° C., and then rise rapidly, and the heat treatment temperature dependence is hardly seen. In addition, it is thought that soft magnetic characteristics are lost due to precipitation of the Fe ₃ B compound at 450 ° C. or higher.

Next, DC magnetic characteristics were measured with the same alloy ribbon as in Example 1 above, and the heat treatment of the coercive force (Hc), the residual magnetic flux density (Br), and the magnetic flux density (B ₈₀ ) when the external magnetic field was 80 A / m. Dependency was examined. FIG. 12 shows an example of the present invention in which the roll contact surface is wound outward, and FIG. 13 shows the result of a comparative example in which the roll contact surface is wound inward.
From the figure, it can be seen that the DC magnetic characteristics are also different depending on the winding method. If the residual magnetic flux density Br and the magnetic flux density B ₈₀ is the present invention, but gradually rises has changed to decline at 430 ° C.. On the other hand, in the case of a comparative example, when it exceeds 430 degreeC, an upward tendency is shown. In the comparative example, the coercive force Hc gradually increases and rapidly increases when the temperature exceeds 430 ° C., but in the present invention, the coercive force Hc gradually decreases and reaches a minimum value at 430 ° C., and then increases. The values of the residual magnetic flux density Br, the magnetic flux density B ₈₀ and the coercive force Hc are all better than those of the comparative example, and it can be seen that a high magnetic flux density and a low coercive force are obtained around 430 ° C.

Example 2
Using an alloy ribbon having a composition of Fe _bal. Ni ₁ Cu _1.5 Si ₄ B ₁₄ and a width of 25 mm and a thickness of 20 μm, a wound core B (outer diameter 26.2 mm-inner diameter 22.2 mm) and a wound core C (outer diameter 74 mm- For the inner diameter of 70 mm, two types were prepared: an outer winding with the roll contact surface wound outward (invention example) and an inner winding with the roll contact surface wound inward (comparative example).
These cores were measured for changes in iron loss (P) and excitation power (S) at 1.55T and 50Hz when the heat treatment temperature was changed. FIG. 14 shows the result of the wound core B, and FIG. 15 shows the result of the wound core C. The solid line is the outer winding. The dotted line is the inner volume.
14 and 15, it can be seen that, along with the iron loss P and the excitation power S, the direction where the roll contact surface is externally wound is smaller than that of the internal volume. However, the effect as much as the wound core A is not seen, and it is considered that the reduction effect becomes dull as the diameter of the wound core increases.

Example 3
Next, FIG. 16 and FIG. 17 show the dependence of the iron loss P and the excitation power S on the magnetic core diameter depending on the winding diameter of the wound magnetic core.
From the figure, it can be seen that both the iron loss and the excitation power can be reduced in the number of the outer winding regardless of the winding diameter, and the effect can be expected more when the roll contact surface is the outer winding than when the inner winding is performed. Although it is considered that this tendency does not change even when the winding diameter increases, a smaller winding diameter is more effective, and a remarkable difference appears particularly at 20 mm.

Next, Fe _bal .Cu _1.4 Si ₄ B ₁₄ prepared in Sample 1-1, Fe _bal .Cu _1.7 Si ₄ B ₂₀ prepared in Sample 1-22, and Fe _bal .Cu _1.4 prepared in Sample 1-28. with B _19, it was measured to produce the same winding core as in example 1. As a result, the result of the same tendency was obtained.

Example 4
An alloy ribbon having a composition of Fe _bal Cu _1.5 Si ₆ B ₉ P ₂ with a width of 25 mm and a thickness of 22 μm was prepared, and the outer surface of the roll contact surface was wound outward (invention example) and the roll contact surface was inward. Two types of wound cores with an outer diameter of 19 mm and an inner diameter of 15 mm were prepared. These wound cores were heated from room temperature, held at 430 ° C. for 1 hour, then cooled in a furnace and subjected to heat treatment in a magnetic field. During the heat treatment in a magnetic field, a 1500 A / m magnetic field was applied in the magnetic path direction during the entire heat treatment. The wound core after heat treatment was placed in a phenolic resin core case, wound, and measured for iron loss (P) and excitation power (S) at 1.55 T and 50 Hz. P of the presently wound core of the present invention wound outside the roll contact surface is 0.38 W / kg, S is 0.48 VA / kg, and P is 0.43 W / kg for the inner wound core wound inside the roll contact surface. kg and S were 1.01 VA / kg, and the wound core of the present invention was superior in both P and S. As a result of microstructural observation, a crystal grain layer with an average grain size of 55 nm exists in the region of 2.9 μm or less from the roll contact surface of the heat-treated alloy, and the interior exceeding 2.9 μm from the roll contact surface is an amorphous matrix It was confirmed that the crystal grains having an average grain size of 23 nm were dispersed therein.

The wound magnetic core of the present invention is suitable for magnetic parts such as a distribution transformer, a high-frequency transformer, various reactors, and a magnetic switch. In addition, a plurality of soft magnetic alloy ribbons are laminated to form a laminated body, and these laminated bodies are further laminated to form a laminated structure, which is also suitable for a wound core for a transformer wound in a step wrap or overlap shape. It is.

Claims (2)

General formula: Fe100-xy-zAxByXz (where A is Cu and / or Au, and X is at least one element selected from Si, S, C, P, Al, Ge, Ga and Be) , X, y, and z are each a number that satisfies the following conditions: 0 <x ≦ 5, 4 ≦ y ≦ 22, 0 ≦ z ≦ 15, and x + y + z ≦ 25. , Having a structure in which fine crystal grains having an average grain size of 60 nm or less are dispersed in an amorphous matrix at a ratio of 30% by volume or more, a ribbon thickness of 16 to 25 μm, and 2.9 μm or less from the roll contact surface. A wound magnetic core comprising a Fe-based nanocrystalline soft magnetic alloy ribbon in which a layer containing coarse crystal grains having an average grain size that is at least twice the average grain size of the fine crystal grains is formed. Make sure that the roll contact surface of the nanocrystalline soft magnetic alloy ribbon is wound outward. Characteristic wound magnetic core. A magnetic component comprising the wound magnetic core according to claim 1.