EP0299498A1 - Magnetkern und Verfahren zur Herstellung - Google Patents

Magnetkern und Verfahren zur Herstellung Download PDF

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EP0299498A1
EP0299498A1 EP88111364A EP88111364A EP0299498A1 EP 0299498 A1 EP0299498 A1 EP 0299498A1 EP 88111364 A EP88111364 A EP 88111364A EP 88111364 A EP88111364 A EP 88111364A EP 0299498 A1 EP0299498 A1 EP 0299498A1
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magnetic
alloy
core
magnetic core
reactor
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French (fr)
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EP0299498B1 (de
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Yoshihito Yoshizawa
Kiyotaka Yamauchi
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Proterial Ltd
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Hitachi Metals Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C45/00—Amorphous alloys
    • C22C45/02—Amorphous alloys with iron as the major constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/153—Amorphous metallic alloys, e.g. glassy metals
    • H01F1/15308—Amorphous metallic alloys, e.g. glassy metals based on Fe/Ni
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
    • H01F41/0226—Manufacturing of magnetic circuits made from strip(s) or ribbon(s) from amorphous ribbons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
    • H01F29/14—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias
    • H01F2029/143—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias with control winding for generating magnetic bias

Definitions

  • the present invention relates to a magnetic core having good magnetic characteristics which are less changeable with time, and more particularly to a magnetic core for semiconductor circuit reactors, common mode chokes transformers, motors, etc.
  • Magnetic cores for the above applications are generally required to have small magnetostriction, high effective permeability and a high saturation magnetic flux density, and also it is required that these magnetic properties are less changeable with time, meaning that they have good durability.
  • the magnetic cores are required to have a low core loss and good control magnetization characteristics (a low uncontrollable magnetic flux density).
  • a semiconductor circuit reactor is used to prevent electric current larger than a rated value from flowing through a semiconductor circuit due to current spike or electric linking generated by on and off of the semiconductor circuit, thereby avoiding the breakage of the semiconductor circuit, and also to prevent errors due to noises.
  • a reactor is particularly required to have high effective permeability and a high squareness ratio to suppress the above abnormal current.
  • a magnetic core For a common mode choke, a magnetic core should have a large operable effective magnetic flux range to prevent a monopolar noise, and it should have a small squareness ratio of a DC B-H curve.
  • a magnetic core For a transformer, a magnetic core should have a small squareness ratio of a DC B-H curve to prevent a monopolar noise as in a common mode choke, and it is required to have excellent high-frequency characteristics, particularly a small core loss at high frequency, because recent switching power supplies have been getting operated at higher frequency.
  • Fe-base and Co-base amorphous alloys have been getting much attention.
  • Co-base amorphous alloys have a small magnetostriction and high effective permeability.
  • Their use for saturable reactors were proposed by Japanese Patent Laid-Open Nos. 57-210612 and 57-21512.
  • Fe-base amorphous alloys have higher saturation magnetic flux density than Co-base amorphous alloys and also Fe-base amorphous alloys can have high squareness ratio when heat-treated in a non-oxidizing atmosphere as described in Japanese Patent Publication No. 58-1183.
  • the Fe-base amorphous alloys have higher saturation magnetic flux density than the Co-­base amorphous alloys, the former alloys are inferior to the latter alloys in a core loss and control magnetization characteristics, particularly when they are used for a saturable reactor in a magnetic amplification circuit of a switching power supply operated at a high frequency of 20 kHz or more.
  • the Fe-base amorphous alloys have large total control magnetization force, large control magnetization current is required to control output voltage, leading to temperature increase of the magnetic core, and also increasing a load of the control circuit, decreasing its efficiency, and making other parts nearby less durable.
  • a semiconductor circuit reactor is formed from an Fe-base amorphous alloy, it shows extremely high magnetostriction and low effective permeability, so that spike current, etc. cannot effectively be prevented.
  • a transformer of a switching power supply is conventionally made of Mn-Zn ferrite, but it was proposed by Denkitsushin Gakkai Technical Report PE 84-­3812 to use an Fe-base amorphous alloy for a transformer of a switching power supply operable at high frequency.
  • the core shows large magnetostriction, which leads to deterioration of magnetic properties by mechanical stress, and also the deterioration of high-frequency magnetic characteristics takes place when the core is cut or impregnated with a resin.
  • Japanese Patent Laid-Open No. 62-101008 discloses a pseudo-crystalline material having fine crystalline particles of 0.1 ⁇ m or less uniformly dispersed in an amorphous matrix phase in a volume larger than that of the matrix phase, which may be used as a magnetic core with magnetic characteristics little changeable with time in a magnetic circuit.
  • This pseudo-crystalline material has improved heat resistance, but its magnetic properties are not so improved.
  • an object of the present invention is to provide a magnetic core having high saturation magnetic flux density and effective permeability and a low core loss.
  • a magnetic core can be produced from an Fe-base soft magnetic alloy consisting essentially of Fe, Cu and M, wherein M is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, at least 50% of the alloy structure being occupied by fine crystalline particles, the magnetic core having a change ratio of effective permeability with time (X) of 0.3 or less.
  • the magnetic core of the present invention having a change ratio of effective permeability with time (X) of 0.3 or less is generally produced from an Fe-base soft magnetic alloy consisting essentially of Fe, Cu and M, wherein M is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, at least 50% of the alloy structure being occupied by fine crystalline particles.
  • the Fe-base soft magnetic alloy used for the magnetic core according to the present invention may generally have the composition represented by the general formula: (Fe 1-a M a ) 100-x-y-z- ⁇ Cu x Si y B z M′ ⁇ wherein M is Co and/or Ni, M′ is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and a, x, y, z and ⁇ respectively satisfy 0 ⁇ a ⁇ 0.5, 0.1 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 30, 0 ⁇ z ⁇ 25, 5 ⁇ y+z ⁇ 30 and 0.1 ⁇ ⁇ ⁇ 30, at least 50% of the alloy structure being occupied by fine crystalline particles.
  • Fe-base soft magnetic alloy suitable for the present invention has the composition represented by the general formula: (Fe 1-a M a ) 100-x-y-z- ⁇ - ⁇ - ⁇ Cu x Si y B z M′ ⁇ M ⁇ ⁇ X ⁇ wherein M is Co and/or Ni, M′ is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M ⁇ is at least one element selected from the group consisting of V, Cr, Mn, Al , elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z , ⁇ , ⁇ and ⁇ respectively satisfy 0 ⁇ a ⁇ 0.5, 0.1 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 30, 0 ⁇ z ⁇ 25, 5 ⁇ y+z ⁇ 30, 0.1
  • Fe may be substituted by Co and/or Ni in the range of up to 0.3.
  • M Co and/or Ni
  • the content of Co and/or Ni which is represented by "a” is preferably 0-0.1.
  • the range of "a” is preferably 0-0.05.
  • Cu is an indispensable element, and its content "x" is 0.1-3 atomic %. When it is less than 0.1 atomic %, substantially no effect on the reduction of core loss and on the increase in permeability can be obtained by the addition of Cu. On ther other hand, when it exceeds 3 atomic %, the resulting magnetic core's control magnetization properties become lower than those containing no Cu.
  • the preferred content of Cu in the present invention is 0.5-2 atomic %, in which range the magnetic core can have control magnetization properties comparable to those of Co-base amorphous alloy magnetic cores.
  • Cu and Fe have a positive interaction parameter so that their sulubility is low. Accordingly, when the alloy is heated while it is amorphous, iron atoms or copper atoms tend to gather to form clusters, thereby producing compositional fluctuation. This produces a lot of domains likely to be crystallized to provide nuclei for generating fine crystalline particles. These crystalline particles are based on Fe, and since Cu is substantially not soluble in Fe, Cu is ejected from the fine crystalline particles, whereby the Cu content in the vicinity of the crystalline particles becomes high. This presumably suppresses the growth of crystalline particles.
  • the crystalline particles are made fine, and this phenomenon is accelerated by the inclusion of Nb, Ta, W, Mo, Zr, Hf, Ti, etc.
  • the crystalline particles are not fully made fine and thus the soft magnetic properties of the resulting alloy are poor.
  • Nb and Mo are effective, and particularly Nb acts to keep the crystalline particles fine, thereby providing excellent soft magnetic properties.
  • the Fe-base soft magnetic alloy has smaller magnetostriction than Fe-­base amorphous alloys, which means that the Fe-base soft magnetic alloy has smaller magnetic anisotropy due to internal stress-strain, resulting in improved soft magnetic properties.
  • the crystalline particles are unlikely to be made fine. Instead, a compound phase is likely to be formed and crystallized, thereby deteriorating the magnetic properties.
  • Si and B are elements particularly for making fine the alloy structure.
  • the Fe-base soft magnetic alloy is desirably produced by once forming an amorphous alloy with the addition of Si and B, and then forming fine crystalline particles by heat treatment.
  • the content of Si ("y”) and that of B ("z") are 0 ⁇ y ⁇ 30 atomic %, 0 ⁇ z ⁇ 25 atomic %, and 5 ⁇ y+z ⁇ 30 atomic %, because the alloy would have an extremely reduced saturation magnetic flux density if otherwise.
  • the preferred range of y is 6-25 atomic %, and the preferred range of z is 2-25 atomic %, and the preferred range of y+z is 14-30 atomic %.
  • the resulting alloy has a relatively large magnetostriction under the condition of providing good soft magnetic properties, and when y is less than 6 atomic %, sufficient soft magnetic properties are not necessarily obtained.
  • the reasons for limiting the content of B ("z") is that when z is less than 2 atomic %, uniform crystalline particle structure cannot easily be obtained, somewhat deteriorating the soft magnetic properties, and when z exceeds 25 atomic %, the resulting alloy would have a relatively large magnetostriction under the heat treatment condition of providing good soft magnetic properties.
  • the contents of Si and B are 10 ⁇ y ⁇ 25, 3 ⁇ z ⁇ 18 and 18 ⁇ y+z ⁇ 28, and this range provides the alloy with excellent soft magnetic properties, particularly a saturation magnetostriction in the range of -5 ⁇ 10 ⁇ 6 ⁇ +5 ⁇ 10 ⁇ 6.
  • Particularly preferred ranges are 11 ⁇ y ⁇ 24, 3 ⁇ z ⁇ 9 and 18 ⁇ y+z ⁇ 27, and this range provides the alloy with a saturation magnetrostriction in the range of -1.5 ⁇ 10 ⁇ 6 ⁇ +1.5 ⁇ 10 ⁇ 8.
  • M′ when added together with Cu, acts to make the precipitated crystalline particles fine.
  • M′ is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo. These elements have a function of elevating the crystallization temperature of the alloy. Synergistically with Cu having a function of forming clusters and thus lowering the crystallization temperature, Nb, etc. suppress the growth of the precipitated crystalline particles, thereby making them fine.
  • the content of M′ ( ⁇ ) is 0.1-30 atomic %. When it is less than 0.1 atomic %, sufficient effect of making crystalline particles fine cannot be obtained, and when it exceeds 30 atomic % an extreme decrease in saturation magnetic flux density ensues.
  • the preferred content of M′ is 0.1-10 atomic %, and more preferably ⁇ is 2-8 atomic %, in which range particularly excellent soft magnetic properties are obtained.
  • most preferable as M′ is Nb and/or Mo, and particularly Nb in terms of magnetic properties.
  • the addition of M′ provides the Fe-base soft magnetic alloy with as high permeability as that of the Co-­base, high-permeability materials.
  • M ⁇ which is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, may be added for the purposes of improving corrosion resistance or magnetic properties and of adjusting magnetostriction, but its content is at most 10 atomic %. When the content of M ⁇ exceeds 10 atomic %, an extreme decrease in a saturation magnetic flux density ensues. A particularly preferred amount of M ⁇ is 5 atomic % or less.
  • At least one element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Au, Cr and V is capable of providing the alloy with particularly excellent corrosion resistance and wear resistance, thereby making it suitable for magnetic heads, etc.
  • the Fe-base soft magnetic alloy may contain 10 atomic % or less of at least one element X selected from the group consisting of C, Ge, P, Ga, Sb, In, Be, As. These elements are effective for making the alloy amorphous, and when added with Si and B, they help make the alloy amorphous and also are effective for adjusting the magnetostriction and Curie temperature of the alloy.
  • the general ranges of a, x, y, z and ⁇ are 0 ⁇ a ⁇ 0.5 0.1 ⁇ x ⁇ 3 0 ⁇ y ⁇ 30 0 ⁇ z ⁇ 25 5 ⁇ y+z ⁇ 30 0.1 ⁇ ⁇ ⁇ 30, and the preferred ranges thereof are 0 ⁇ a ⁇ 0.3 0.1 ⁇ x ⁇ 3 0 ⁇ y ⁇ 25 2 ⁇ z ⁇ 25 14 ⁇ y+z ⁇ 30 0.1 ⁇ ⁇ ⁇ 10, and the more preferable ranges are 0 ⁇ a ⁇ 0.1 0.5 ⁇ x ⁇ 2 10 ⁇ y ⁇ 25 3 ⁇ z ⁇ 18 18 ⁇ y+z ⁇ 28 2 ⁇ ⁇ ⁇ 8, and the most preferable ranges are 0 ⁇ a ⁇ 0.05 0.5 ⁇ x ⁇ 2 11 ⁇ y ⁇ 24 3 ⁇ z ⁇ 9 18 ⁇ y+z
  • the general ranges of a, x, y, z, ⁇ , ⁇ and ⁇ are 0 ⁇ a ⁇ 0.5 0 ⁇ x ⁇ 3 0.1 ⁇ y ⁇ 30 0 ⁇ z ⁇ 25 5 ⁇ y+z ⁇ 30 0.1 ⁇ ⁇ ⁇ 30 ⁇ ⁇ 10 ⁇ ⁇ 10, and the preferred ranges are 0 ⁇ a ⁇ 0.3 0.1 ⁇ x ⁇ 3 6 ⁇ y ⁇ 25 2 ⁇ z ⁇ 25 14 ⁇ y+z ⁇ 30 0.1 ⁇ ⁇ ⁇ 10 ⁇ ⁇ 5 ⁇ ⁇ 5, and the more preferable ranges are 0 ⁇ a ⁇ 0.1 0.5 ⁇ x ⁇ 2 10 ⁇ y ⁇ 25 3 ⁇ z ⁇ 18 18 ⁇ y+z ⁇ 28 2 ⁇ ⁇ ⁇ 8 ⁇ ⁇
  • the Fe-base soft magnetic alloy having the above composition has an alloy structure, at least 50% of which consists of fine crystalline particles. These crystalline particles are based on ⁇ -Fe having a bcc structure, in which Si and B, etc. are dissolved. These crystalline particles have an extremely small average particle size of 1000 ⁇ or less, and are uniformly distributed in the alloy structure. Incidentally, the average particle size of the crystalline particles is determined by measuring the maximum size of each particle and averaging them. When the average particle size exceeds 1000 ⁇ , good soft magnetic properties are not obtained. It is preferably 500 ⁇ or less, more preferably 200 ⁇ or less and particularly 50-200 ⁇ . The remaining portion of the alloy structure other than the fine crystalline particles may be mainly amorphous. Even with fine crystalline particles occupying substantially 100% of the alloy structure, the Fe-base soft magnetic alloy has sufficiently good magnetic properties.
  • an alloy melt of the above composition is rapidly quenched by known liquid quenching methods such as a single roll method, a double roll method, etc. to form amorphous alloy ribbons.
  • amorphous alloy ribbons produced by the single roll method, etc. have a thickness of 5-100 ⁇ m or so, and those having a thickness of 25 ⁇ m or less are particularly suitable as magnetic core materials for use at high frequency.
  • amorphous alloys may contain crystal phases, but the alloy structure is preferably amorphous to make sure the formation of uniform fine crystalline particles by a subsequent heat treatment.
  • the Fe-base soft magnetic alloy containing fine crystalline particles can be produced directly by the liquid quenching method without resorting to heat treatment, as long as proper conditions are selected.
  • the amorphous ribbons are wound, punched, etched or subjected to any other working to desired shapes before heat treatment, for the reasons that the ribbons have good workability in an amorphous state, but that once crystallized they lose such workability.
  • the heat treatment is carried out by heating the amorphous alloy ribbon worked to have the desired shape in vacuum or in an inert gas atmosphere such as hydrogen, nitrogen, argon, etc.
  • the temperature and time of the heat treatment vary depending upon the composition of the amorphous alloy ribbon and the shape and size of a magnetic core made from the amorphous alloy ribbon, etc., but in general it is preferably 450-700°C for 5 minutes to 24 hours.
  • the heat treatment temperature is lower than 450 °C, crystallization is unlikely to take place with ease, requiring too much time for the heat treatment.
  • it exceeds 700°C coarse crystalline particles tend to be formed, making it difficult to obtain fine crystalline particles.
  • the preferred heat treatment conditions are, taking into consideration practicality and uniform temperature control, etc., 500-650°C for 5 minutes to 6 hours.
  • the heat treatment atmosphere is preferably an inert gas atmosphere, but it may be an oxidizing atmosphere such as the air. Cooling may be carried out properly in the air or in a furnace. And the heat treatment may be conducted by a plurality of steps.
  • the heat treatment can be carried out in a magnetic field to provide the alloy with magnetic anisotropy.
  • a magnetic field is applied in parallel to the magnetic path of the magnetic core of the present invention in the heat treatment step, the resulting heat-­treated magnetic core has a good squareness ratio in a B-H curve thereof, so that it is particularly suitable for saturable reactors, magnetic switches, pulse compression cores, reactors for preventing spike voltage, etc.
  • the heat treatment is conducted while applying a magnetic field in perpendicular to the magnetic path of a magnetic core, the B-H curve inclines, providing it with a small squareness ratio and a constant permeability. Thus, it has a wider operational range and thus is suitable for transformers, noise filters, choke coils, etc.
  • the magnetic field need not be applied always during the heat treatment, and it is necessary only when the alloy is at a temperature lower than the Curie temperature Tc thereof.
  • the alloy has an elevated Curie temperature because of crystallization than the amorphous counterpart, and so the heat treatment in a magnetic field can be carried out at temperature higher than the Curie temperature of the corresponding amorphous alloy.
  • the heat treatment in a magnetic field it may be carried out by two or more steps.
  • a rotational magnetic field can be applied during the heat treatment.
  • the magnetic core of the present invention preferably has a saturation magnetic flux density B s of 10kG or more and effective permeability ⁇ elkHz of 5 x 103 or more.
  • the heating test can be conducted in a constant-temperature furnace.
  • This change ratio X should be 0.3 or less, and is preferably 0.1 or less and more preferably 0.05 or less.
  • the magnetic core has saturation magnetostriction ⁇ s of +5 ⁇ 10 ⁇ 6 ⁇ -5 ⁇ 10 ⁇ 6, and more particularly +1.5 ⁇ 10 ⁇ 6 ⁇ -1.5 ⁇ 10 ⁇ 6.
  • a saturable reactor By using the Fe-base soft magnetic alloy having the above composition and characteristics, a saturable reactor, a semiconductor circuit reactor, a common mode choke, a normal mode choke, a high-frequency transformer, a motor core, etc. can be provided.
  • the magnetic core for both reactors should have a squareness ratio B r /B10 of a DC B-H curve which is desirably 70% or more and particularly 80% or more.
  • B r means a residual magnetic flux density
  • B10 means a magnetic flux density at 10 Oe which is almost equal to a saturation magnetic flux density.
  • the magnetic core has an uncontrollable magnetic flux density ⁇ B b of 3kG or less at 50kHz to prevent voltage from changing when load current increases.
  • the magnetic core of the present invention When used for a reactor for a semiconductor circuit, it shows an excellent function of preventing spike voltage from flowing through the semiconductor circuit.
  • DC B-H curve desirably has a squareness ratio B r /B10 of 30% or less.
  • This insulating layer can be formed by various method. For instance, it can be formed by attaching insulating powder such as SiO2, MgO, Al2O3, etc. to the ribbon surface by immersion, spraying, electrophoresis, etc. A thin layer of SiO2, etc. may be formed by sputtering or vapor deposition. Alternatively, a mixture of a solution of modified alkylsilicate in alcohol with an acid may be applied to the ribbon. Further, a forsterite (MgSiO4) layer may be formed by heat treatment.
  • insulating powder such as SiO2, MgO, Al2O3, etc.
  • a thin layer of SiO2, etc. may be formed by sputtering or vapor deposition.
  • a mixture of a solution of modified alkylsilicate in alcohol with an acid may be applied to the ribbon.
  • a forsterite (MgSiO4) layer may be formed by heat treatment.
  • a sol obtained by partially hydrolyzing SiO2-TiO2 metal alkoxide may be mixed with various ceramic powder, and the resulting mixture may be applied to the ribbon. Further, a solution mainly containing a polytitanocarbo­silane may be applied to the ribbon and then heated. Further, a phosphate solution may be applied and heated. In addition, the insulating layer may be formed by applying an oxidizing agent to the ribbon and heating it.
  • the wound core may consist of the alloy ribbon and an insulating tape interposed between the adjacent ribbon layers.
  • This wound core can be formed by laying the insulating tape on the ribbon and winding them.
  • This insulating tape may be a polyimide tape, a ceramic fiber insulating tape, a polyester tape, an aramide tape, a glass fiber tape, etc.
  • the wound core containing such tape may be subjected to heat treatment.
  • an insulating thin film is inserted between the adjacent layers to achieve insulating between the alloy sheet layers.
  • materials having no flexibility such as ceramics, glass, mica, etc. may be used for the insulating thin film. When these materials are used, heat treatment can be conducted after lamination.
  • an inner end and an outer end of the ribbon should be fixed to the wound core body to prevent loosening of the wound core.
  • the fixing of the ribbon ends can be conducted by applying a laser beam or electric energy to a spot for fixing, or by using an adhesive or an adhesive tape.
  • the Fe-base soft magnetic alloy ribbon is desirably plated or coated to prevent corrosion.
  • the wound core may be contained in an insulating case, and such a material as grease can be used to fill a space between the wound core and the case to ensure the insulation and anti-corrosion of the wound core. Because the magnetic core of the present invention is made of an Fe-­base alloy, its isolation from the air is particularly important.
  • a melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 7.2% B, 2.5% Nb and balance substantially Fe was formed into a ribbon of 4.5 mm in width and 18 ⁇ m in thickness by a single roll method.
  • the X-ray diffraction of this ribbon showed a halo pattern peculiar to an amorphous alloy in Fig. 2.
  • a transmission electron photomicrograph of this ribbon also showed no crystal particles in the alloy structure. As is clear from the X-­ray diffraction and the transmission electron photomicrograph, the resulting ribbon was almost completely amorphous.
  • this amorphous ribbon was formed into a toroidal wound core of 10 mm in inner diameter and 13 mm in outer diameter as shown in Fig. 5, and then heat-treated in a nitrogen gas atmosphere at 550 °C for one hour.
  • This toroidal wound core was contained in a core case made of a phenol resin, and 10 turns of wires were wound around it on both primary and secondary sides.
  • This magnetic core was placed in a constant-temperature furnace at 100 °C to measure the change of its effective permeability with time.
  • Fig. 1 denotes the magnetic core of this Example.
  • A denotes the magnetic core of this Example.
  • an amorphous alloy having the composition (by atomic %) of 0.4% Fe, 5.9% Mn, 15% Si, 9% B and balance substantially Co and an Fe-base amorphous alloy having the same composition as A1 (this Example) without heat treatment was formed into magnetic cores in the same manner as above, and their effective permeability was measured with the lapse of time.
  • Fig. 1 denotes the magnetic core of this Example.
  • B1 denotes the magnetic core made of the Co-­base amorphous alloy
  • C1 the magnetic core made of the Fe-base amorphous alloy (Fe bat Cu1Nb 2.5 Si 13.5 B 7.2 ) which was not heat-treated.
  • the magnetic core of the present invention was decomposed to analyze the metal structure of its ribbon by X-ray diffraction and transmission electron microscopy.
  • Fig. 3(a) shows the X-ray diffraction pattern of the Fe-base alloy of this Example
  • Fig. 3(b) schematically shows the transmission electron photomicrograph of the same Fe-base alloy in which 1 denotes fine crystalline particles or grains and 2 a matrix phase. It is presumed that this matrix phase is amorphous, but when the heat treatment temperature is high, it may be converted to a fine crystal phase.
  • the Fe-base alloy of this Example contains extremely fine crystalline particles made of a bcc Fe solid solution having a particle size of 50-200 ⁇ .
  • This Example shows the measurement of control magnetization properties of a magnetic core.
  • Fig. 6 shows a circuit for measuring the control magnetization properties, which is equivalent to that for evaluating a saturable reactor.
  • Fig. 7 is a schematic view showing the characteristics of a saturable reactor when DC control current Ic flows through the control circuit.
  • sample S is a saturable reactor constituted by a magnetic core and 3 windings N L , N c and N v .
  • N L which corresponds to an output winding of the saturable reactor used in the magnetic amplifier, is connected to an AC power source Eg having a frequency f (period: Tp) via resistor R L and rectifier D.
  • Eg is set such that the magnetic core becomes saturated at a phase angle within 90° of applied sinusoidal voltage in a half-period Tg of a gate.
  • N c is a control winding, and it is connected to DC power source Ec via inductor L c having sufficiently large inductance as compared to the inductance of the magnetic core to give DC magnetization to the magnetic core.
  • N v is a winding for measuring reset magnetic flux ⁇ ⁇ cm corresponding to control input, and it is connected to an AC voltmeter of a mean value rectification type.
  • Fig. 7 schematically shows a control magnetization curve measured by this circuit.
  • G0 ⁇ 0 ⁇ ⁇ 0
  • H Lm - ⁇ B b B m - B r (4) and E vd ⁇ f ⁇ N v ⁇ A ⁇ ⁇ B b (5)
  • ⁇ B ⁇ B cm - ⁇ B b (6)
  • a melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 9% B, 3% Nb and balance substantially Fe was formed into a ribbon of 4.5 mm in width and 18 ⁇ m in thickness by a single roll method. This ribbon was almost completely amorphous. This ribbon was formed into a toroidal wound core of 10 mm in inner diameter and 13 mm in outer diameter. This alloy had a crystallization temperature of 508°C when measured at a heating rate of 10 °C /min and a Curie temperature of about 310°C.
  • Each wound core was contained in a phenol resin core case, and 10 turns of wires were wound around each magnetic core on both primary and secondary sides to provide a saturable reactor as in Example 1.
  • the characteristics of each magnetic core were measured. The results are shown in Table 1.
  • Table 1 Heat Treatment Condition B10 (kG) B r /B10 (%) H c (Oe) W 2/100k (mW/cc) (a) 12.4 70 0.008 340 (b) 12.4 90 0.005 790 (c) 12.4 82 0.007 610 (d) 12.4 87 0.005 820 (e) 12.4 83 0.005 680 (f) 12.4 83 0.006 680 (g) 12.4 91 0.007 810 (h) 12.4 88 0.008 780
  • the alloy heat-treated by the pattern (b) in Fig. 4 had a Curie temperature Tc of 570°C and saturation magnetostriction ⁇ s of 3.8 ⁇ 10 ⁇ 6.
  • a melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 9% B, 5% Nb and balance substantially Fe was formed into a ribbon of 5 mm in width and 18 ⁇ m in thickness by a single roll method.
  • This alloy had a crystallization temperature of 533°C when measured at a heating rate of 10°C/min. And its Curie temperature was 260 °C.
  • this ribbon was coated with MgO powder by electrophoresis, and formed into a wound core of 19 mm in outer diameter and 15 mm in inner diameter.
  • This wound core was heated at 610°C for 1 hour in an N2 gas atmosphere, and cooled to 250 °C at a cooling rate of 5°C/min in a magnetic field of 5 Oe in parallel with the magnetic path of the magnetic core. After keeping it at 250°C for 4 hours, it was cooled to room temperature at a cooling rate of about 60°C/min.
  • Another wound core of the same composition and the same structure was heated at 610°C for 1 hour, and then cooled to room temperature at a cooling rate of 100°C/min in a magnetic field of 5 Oe in parallel with the magnetic path of the magnetic core.
  • each of these cores was contained in a phenol resin core case, and 10 turns of wires were wound around each magnetic core on both primary and secondary sides to provide a saturable reactor. The characteristics of each saturable reactor were tested. The results are shown in Table 2.
  • these magnetic cores have high squareness ratio suitable for a saturable reactor.
  • the alloy heat-treated by the pattern (b) had a main phase having a Curie temperature of 550°C and saturation magnetostriction ⁇ s of 1 ⁇ 10 ⁇ 6.
  • Saturable reactors were produced by using an Fe 73. 5Cu1Nb3Si 13.5 B9 alloy A2, an Fe 71.5 Cu1Nb5Si 13.5 B3 alloy A3, an Fe 71.5 Cu1Nb5Si 13.5 B9 alloy A4, a high-squareness ratio Fe-base amorphous alloy C2 (Fe 69.3 Ni 7.7 Si13B10) and two high-squareness ratio Co-base amorphous alloys B2, B3 (Co 69. 7Fe 0.4 Mn 5.9 Si15B9, Co67Fe4Mo 1.5 Si 16.5 B11), respectively.
  • the alloy A2 was heat-treated by heating it at 550°C for 1 hour, cooling down to 280 °C and keeping it at that temperature for 1 hour while applying a magnetic field of 2 Oe in the direction of the magnetic path
  • the alloy A3 was heat-treated by heating it at 610°C for 1 hour, cooling it down to 250°C and then keeping it at that temperature for 2 hours while applying a magnetic field of 15 Oe in the direction of the magnetic path
  • the alloy A4 was heat-­treated by heating it at 610 °C for 1 hour and then air-­cooling it while applying a magnetic field of 2 Oe in the direction of the magnetic path.
  • B r /B10 of each alloy was as follows: B r /B10(%) ALLOY A2 93 ALLOY A3 89 ALLOY A4 87 ALLOY C2 90 ALLOY B2 95 ALLOY B3 85
  • the alloys A2, A3, A4, B2 and B3 shown in Fig. 9 were used to provide saturable reactors, and their control magnetization characteristics were evaluated by the circuit shown in Fig. 6.
  • the primary winding (N v ) and the secondary winding (N L ) were respectively 17 turns and the control winding (N c ) was 5 turns.
  • the results are shown in Fig. 10.
  • the saturable reactor of the present invention had a control magnetization force comparable to that of high-squareness ratio Co-base amorphous alloy for the same ⁇ B, but the former had a total controllable magnetic density ⁇ B m 1.5 ⁇ 2 times as large as that of the Co-base amorphous alloy saturable reactor. Accordingly, the saturable reactor of the present invention can be miniaturized under the conditions that temperature increase of the core does not pose serious problems.
  • a saturable reactor produced from a finely crystallized alloy consisting essentially of 1% Cu, 13.5% Si, 9% B, 3% Nb and substantially balance Fe (by atomic %), and the temperature characteristics of its magnetic properties were measured. The results are shown in Fig. 11.
  • Alloy melts having compositions shown in Table 3 were formed into amorphous ribbons each having a width of 5 mm and a thickness of 18 ⁇ m by a single roll method. Each ribbon was formed into a wound core of 19mm in outer diameter and 15 mm in inner diameter. Each wound core was heat-treated to form extremely fine crystalline particles in the alloy structure. The heat treatment conditions were according to the heat treatment pattern (b) in Fig. 4.
  • Each wound core was contained in a phenol resin core case and 10 turns of wires were wound around each wound core on both primary and secondary sides to provide a saturable reactor as in Example 1.
  • a DC B-H curve, an AC B-H curve, a core loss W 2/100k at 100 kHz and 2 kG, and control magnetization curve at 50 kHz were measured.
  • the control magnetization curve was measured for a saturable reactor of the same structure as in Example 6 by a method shown in Example 2.
  • the saturable reactors of the present invention had higher B10 than those of the Co-base amorphous alloys and 80 wt% Ni Permalloy, and the former had high squareness ratio.
  • the saturable reactors of the present invention had excellent characteristics comparable to those of the Co-base amorphous alloys in Hc, a core loss, Hr and ⁇ B b .
  • the saturable reactors of the present invention showed a low core loss compared to those produced from the 50 wt% Ni Permalloy and the Fe-base amorphous alloy, which means that the saturable reactor of the present invention has excellent control magnetization characteristics.
  • the saturable reactor of the present invention can be operated by small control current, increasing the effenciency of a circuit.
  • ⁇ B b is small, it enjoys a wide control range.
  • Alloy melts having compositions shown in Table 4 were used to produce wound cores having extremely fine crystalline particles as in Example 8, and each wound core was formed into a saturable reactor.
  • a magnetic flux density B10 at 10 Oe a magnetic flux density B10 at 10 Oe
  • a core loss W 2/100k at 100 kHz and 2 kG a magnetic flux density B10 at 10 Oe
  • a core loss W 2/100k at 100 kHz and 2 kG For each saturable reactor, a magnetic flux density B10 at 10 Oe
  • a core loss W 2/100k at 100 kHz and 2 kG an uncontrollable magnetic flux density ⁇ B b and saturation magnetostriction ⁇ s were measured.
  • the results are shown in Table 4.
  • the saturable reactor of the present invention has a high squareness ratio, low Hc, a low core loss, a low uncontrollable magnetic flux density ⁇ B b than those of the Fe-base amorphous alloy. Further, since it has low ⁇ s, the deterioration of magnetic characteristics by coating, etc. can be avoided.
  • An amorphous alloy ribbon having a composition (by atomic %) of 1% Cu, 13.5% Si, 9% B, 3% Nb and balance substantially Fe, and an amorphous alloy ribbon having a composition (by atomic %) of 13.5% Si, 9% B, 3% Nb and balance substantially Fe were produced.
  • the former amorphous alloy containing both Cu and Nb had a crystallization temperature of 508 °C when measured at a heating rate of 10°C /min, while the latter amorphous alloy (containing no Cu) had a crystallization temperature of 583 °C when measured under the same condition.
  • Each amorphous alloy ribbon was formed into a wound core of 19 mm in outer diameter and 15 mm in inner diameter.
  • the wound core containing Cu-Nb according to the present invention was heated at 550 °C for 1 hour while applying a magnetic field of 10 Oe in the direction of its magnetic path and then cooled down to room temperature at a cooling rate of 20°C /min in order that extremely fine crystalline particles occupy a majority of the alloy structure.
  • the magnetic alloy of the comparative example was heated at 500°C for 1 hour and then cooled down to 280°C at a cooling rate of 5°C /min while applying a magnetic field of 10 Oe in the direction of its magnetic path, and after keeping it at 280 °C for 4 hours, it was cooled down to room temperature at a cooling rate of 20°C /min.
  • the wound core of the comparative example had an amorphous structure. Each of these wound cores was contained in a phenol resin core case, and formed into a saturable reactor by winding a primary wire and a second wire by 20 turns and a control wire by 5 turns.
  • Each saturable reactor was mounted in a magnetic control-type switching power supply having a driving frequency of 100 kHz.
  • This switching power supply had two outputs; an output of 12 V (magnetic amplification control), and an output of 5 V (PWM control).
  • the output characteristics of the saturable reactor were measured.
  • input voltage was AC 100V
  • load current of the 5 V output was changed.
  • 12 V output terminal voltage, power supply effeciency ⁇ and core case surface temperature increase ⁇ T were measured and compared between the two saturable reactors. The results are shown in Fig.
  • a melt having a composition (by atomic %) of 0.8% Cu, 13.6% Si, 9% B, 3% Nb and balance Fe, and a melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 9% B, 5% Nb, and balance Fe were formed into amorphous ribbons by a single roll method.
  • Each of the amorphous ribbons was heat-­treated in an N2 gas atmosphere in a magnetic field of 10 Oe in the direction of the magnetic path thereof.
  • the heat treatment conditions were heating at 550 °C for 1 hour, cooling to 280°C , and keeping at 280°C for 1 hour for the former alloy, and heating at 610°C for 1 hour, cooling to 250°C , and keeping at 250°C for 4 hours for the latter alloy.
  • the magnetic field was applied during the period of heat treatment. By this heat treatment, extremely fine crystalline particles were formed in the alloy structure.
  • Each wound core was contained in the Bakelite core case and 10 turns of wire were wound around each magnetic core on both primary and secondary sides to provide a saturable reactor. The characteristics of each saturable reactor were tested.
  • an amorphous alloy consisting essentially of 15% Si, 9% B, 5.9% Mn and balance substantially Co (by atomic %) was produced and formed into a saturable reactor.
  • Fig. 13 (c) shows its DC B-H curve. It is clear from Fig. 13 that the saturable reactors of the present invention (a) and (b) show higher B10 than that of the Co-base amorphous alloy (c) and they are almost equivalent in a coercive force Hc and a squareness ratio B r /B10. Further, the maximum permeability ⁇ max was 1450k for the Fe 73.6 Cu 0.8 Si 13.6 B9Nb3 alloy and 1000k for the Fe 71. 5 Cu1Si 13.5 B9Nb5 alloy.
  • An alloy melt of Fe 72.5-x Cu x Si 13.5 B9Nb5 (Alloy A6) and an alloy melt of Fe 77.5-x Cu x Si 13.5 B9 (Alloy A7, comparative example) were formed into amorphous ribbons by a single roll method.
  • each ribbon was formed into a wound core of 19 mm in outer diameter and 15 mm in inner diameter, and the resulting wound core was heat-treated under the same conditions as in the heat treatment pattern in Fig. 4 while applying a magnetic field of 20 Oe in the direction of its magnetic path in an N2 gas atmosphere.
  • the heat-treated wound core was then contained in a phenol resin core case and 10 turns of wires were wound on primary and secondary sides to provide a saturable reactor.
  • the saturable reactor was measured with respect to control magnetization characteristic in the circuit shown in Example 2.
  • Fig. 14 shows specific core gains G0 measured at 50 kHz.
  • G0 increases extremely, but when x exceeds 3 G0 undesirably decreases.
  • a melt consisting of 1% Cu, 13.5% Si, 9% B, 3% Nb and balance substantially Fe by atomic % was formed into a ribbon of 3 mm in width and 18 ⁇ m in thickness by a single roll method.
  • This ribbon was subjected to a heat treatment shown by Fig. 4 (b) in Example 3.
  • this ribbon was formed into a wound core and then introduced into a phenol resin case. 20 turns of wires of 0.4 mm in diameter were wound around it to provide a reactor for semiconductor circuit shown in Fig. 16.
  • This reactor was measured with respect to inductance at 1kHz.
  • a ratio of the maximum inductance to the initial inductance was 3.03, and a ratio of the maximum inductance to a residual inductance was 300.
  • the residual inductance is an inductance measured when DC current is applied.
  • the reactor Since the maximum inductance-residual inductance ratio is large, the reactor is excellent in improving the recovery characteristics of a diode.
  • Fig. 17 shows a basic circuit of a switching power supply using the above reactor.
  • 10 denotes a main transformer, 11, 12, 13 each diode, 14 a smoothing choke, 15 the reactor of the present invention, and 16 a load. Input and output were both DC voltage.
  • Fig. 18 shows the wave forms of load current.
  • A denotes a case where no reactor was used, and B denotes a case where the reactor was inserted into a half-wave rectifier circuit operated at a pulse width of 10 ⁇ sec and input voltage of 100V DC.
  • a melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 7% B, 2.5% Nb and substantially balance Fe was formed into an amorphous ribbon of 3 mm in width and 18 ⁇ m in thickness by a single roll method.
  • the ribbon was coated with MgO powder on the side of contact with the single roll. to form an insulating layer. It was then wound to provide a toroidal wound core of 4 mm in outer diameter and 2 mm in inner diameter.
  • This wound core was heat-treated at 550 °C for 1 hour, and its outer surface was coated with an epoxy resin and connected to diode terminals to provide a semiconductor circuit reactor combined with a diode as shown in Fig. 19, in which 20 denotes a diode and 21, 22 denote the reactors of the present invention.
  • this reactor was used in a smoothing circuit on the output side of a switching power supply to measure diode voltage and output noise.
  • the diode voltage was 61.0 V and the output noise was 123 mVp-p, but when it was used the diode voltage was 33.5 V and the output noise was 47.3 mVp-p. Thus it was confirmed that the reactor of the present invention has excellent smoothing and noise reduction effects.
  • Reactors were produced from alloy ribbons having compositions shown in Table 5 in the same manner as in Example 14, and their initial inductance L0 and maximum inductance L m were measured. After heat treatment at 120°C for 1000 hours, their initial inductance L01000 and maximum inductance L m 1000 were also measured to determine ratios of L01000/L0 and L m 1000/L m . The results are shown in Table 5.
  • a melt having a composition (by atomic %) of 1% Cu, 14% Si, 8% B, 5% Nb and balance substantially Fe was formed into an amorphous alloy ribbon of 5 mm in width and 20 ⁇ m in maximum thickness and 17 ⁇ m in average thickness by a single roll method.
  • the ribbon was formed into a toroidal wound core of 6 mm in inner diameter by winding it 20 times and then heat-treated at 600°C for 1 hour in an argon gas atmosphere and then air-cooled.
  • the magnetic core having the same alloy structure as in Example 1 was formed.
  • Alloy melts having compositions shown in Table 6 were rapidly quenched by a single roll method to produce amorphous alloy ribbons, and each of these amorphous ribbons was formed into a toroidal core of 35 mm in outer diameter and 25 mm in inner diameter.
  • Each wound core was heat-­treated at a temperature equal to or higher than its crystallization temperature in a magnetic field of 5000 Oe in perpendicular to its magnetic path to generate extremely fine crystalline particles in the alloy structure. 10 turns of 2 wires were wound around this wound core as shown in Fig. 20 to produce a common mode choke.
  • This common mode choke was measured with respect to DC magnetaic characteristics, a core loss W 2/100k at 2kG, an absolute value of complex permeability at 100 kHz
  • An alloy melt having a composition (by atomic %) of 1% Cu, 16.5% Si, 6% B, 3% Nb and balance substantially Fe was formed into an amorphous ribbon of 7.5 mm in width and 18 ⁇ m in thickness by a single roll method.
  • This amorphous alloy ribbon was wound to form a toroidal core of 19.5 mm in outer diameter and 9.6 mm in inner diameter.
  • This wound core was heat-treated in an N2 atmosphere in a magnetic field of 3000 Oe in perpendicular to the magnetic path. In this heat treatment, it was heated at a heating rate of 10 °C/min, kept at 510°C for 1 hour, cooled down to room temperature at a cooling rate of 2.5°C/min.
  • this common mode choke was used as a line filter in an AC 100V input line for a switching power supply operable at 50kHz.
  • Common mode noise reading from input terminals of the power supply was measured. The results are shown in Fig. 21. It is clear from Fig. 21 that the line filter (denoted by A9) using the common mode choke of the present invention shows larger noise level reduction effects at a lower frequency than that using a Mn-Zn ferrite core (denoted by D).
  • An alloy melt (Alloy A10) having a composition (by atomic %) of 1% Cu, 13.5% Si, 9% B, 3% Nb and balance substantially Fe was formed into an amorphous ribbon by a single roll method.
  • This amorphous ribbon was wound to form a toroidal core of 31 mm in outer diameter and 18 mm in inner diameter.
  • This wound core was heat-treated in an N2 atmosphere by applying a magnetic field of 5000 Oe in perpendicular to its magnetic path, to generate extremely fine crystalline particles in its alloy structure.
  • This wound core was introduced into a Bakelite core case, and 10 turns of wires were wound around it on both primary and secondary sides to measure its magnetic characteristics; DC B-H curve and pulse permeability ⁇ p .
  • the magnetic core of the present invention shows high saturation magnetic flux density and permeability with no variation with time and low squareness ratio and core loss, and that accordingly it is superior to those of comparative examples in the dependency of effective pulse permeability on magnetic flux density variation ⁇ B. Therefore, when used as common mode choke, it is less likely to be saturated by high-voltage noises, keeping high inductance. Thus, it can provide a line filter having excellent high-voltage pulse attenuation characteristics.
  • of this magnetic core was measured. The results are shown in Fig. 24. In Fig.
  • A11 denotes the Fe 73.5 Cu1Nb3Si 13.5 B9 alloy of the present invention
  • B5 denotes the Co 70.7 Fe 0.3 Mn5Si15B 9 amorphous alloy (comparative example)
  • C5 denotes the Fe 77. 5 Si9B 13.5 amorphous alloy (comparative example)
  • D denotes Mn-Zn ferrite.
  • means that it has large attenuation effects to usual noises.
  • the magnetic core of the present invention has
  • An alloy melt having a composition (by atomic %) of 1% Cu, 13.5% Si, 7.2% B, 2.5% Nb and balance substantially Fe was formed into an amorphous ribbon of 6.5 mm in width by a single roll method.
  • This amorphous ribbon was wound to form a toroidal core of 20 mm in outer diameter and 10 mm in inner diameter.
  • This wound core was heat-treated under the following conditions:
  • Fig. 27 (a) A measuring circuit used is shown in Fig. 27 (a), in which 28 denotes a standard signal generator, 29 a selective level meter, 30 a sample, and 31 a power divider. Input signal level was 0 dbm. The results are shown in Fig. 27 (b) together with those of Mn-Zn ferrite D. It has been verified that the common mode choke of the present invention shows better attenuation effects than that of the Mn-Zn ferrite D in all frequency area.
  • each common mode choke comprises a wound core of 12.5 mm in width, 25 mm in outer diameter and 15 mm in inner diameter and 22 turns of 2 wires.
  • a magnetic field if necessary, was applied at 3000 Oe in perpendicular to the magnetic path during heat treatment.
  • the common mode chokes of the present invention show higher absolute values of
  • Table 8 shows magnetic characteristics and high-­voltage pulse characteristics of the common mode chokes of thepresent invention having the structure of Example 23. Incidentally, a magnetic field of 3000 Oe was applied in perpendicular to the magnetic path during heat treatment. In addition, as in Example 23, an absolute value of complex permeability
  • An amorphous alloy ribbon having the same composition as in Example 19 and having a width of 7.5 mm and a thickness of 20 ⁇ m was formed into a toroidal core as shown in Fig. 22 (a), and the toroidal core was heat-­treated while applying a magnetic field of 5000 Oe in perpendicular to its magnetic path during the overall period of heat treatment, to generate fine crystalline particles in the alloy structure.
  • the heat treatment was conducted by heating to 500°C at a heating rate of 20°C­/min, keeping at 500°C for 1 hour, cooling to 280°C at a cooling rate of 5°C/min, keeping at 280°C for 2 hours, and then cooling to room temperature at a cooling rate of 2°C­/min.
  • an amorphous alloy ribbon consisting essentially of 13.5% Si, 9% B, 3% Nb and balance substantially Fe by atomic % was formed into a toroidal core, and a Capton tape was wound around it to produce a transformer core (Comparative Example 1), and the above toroidal core was impregnated with an epoxy resin and then a Capton tape was wound around it to provide a transformer core (Comparative Example 2).
  • the transformer core of the present invention shows much smaller core loss even though it is impregnated with a resin.
  • the finely crystallized alloy having the composition as in Example 20 was formed into an E core shown in Fig. 25 (a), and heat-treated at 550 °C for 1 hour in an Ar atmosphere to generate extremely fine crystalline particles in its alloy structure. And then an E-type transformer core was formed as shown in Fig. 25 (b). A measurement of the magnetic characteristics of this core shows that its saturation magnetic flux density was 12.6kG, more than double that of Mn-Zn ferrite and its core loss W 2/­100k was 280 mW/cc.
  • the core of the present invention suffers from less temperature increase than that of Mn-Zn ferrite, exerting less influence to other elements.
  • An alloy melt of Fe 73.5 Cu1Si 16.5 B6Nb3 (by atomic %) was formed into an amorphous alloy ribbon, and the amorphous alloy ribbon was coated with an MgO layer by an electrophoresis method. It was then wound in the form shown in Fig. 28 (a), and heat-treated at 530 °C for 1 hour and then cooled. After heat treatment, this core was impregnated with varnish and cut at center by a peripheral slicer. The cut portions were ground and lapped to produce a cut core shown in Fig. 28 (b). Its core loss at 100 kHz and 2kG was as low as 500 mW/cc.
  • Such cut core can be formed into a transformer by inserting the bobbin provided with wires into the cut core. Accordingly, it is advantageous in that its winding operation is easy. Also, by providing a gap, the core's effective permeability can be controlled.
  • Fig. 29 shows dependency of a core loss on frequency of the magnetic core of Fe 73.5 Cu1Si 13.5 B9Nb3 (Alloy A16, present invention) as shown in Example 14, together with those of the conventional materials.
  • B6 denotes a Co 69.7 Fe 0.4 Mn 5.8 Si15B9 amorphous alloy
  • C7 denotes an Fe 76.5 Cr1Si 13.5 B9 amorphous alloy
  • D denotes Mn-Zn ferrite.
  • the magnetic core of the present invention showed a core loss which was equal to or smaller than that of the Co-base amorphous alloy (B6) up to a high-frequency region and much smaller than those of the Fe-base amorphous alloy (C7) and the Mn-Zn ferrite (D).
  • the magnetic core of the present invention is excellent as a transformer operable at high frequency.
  • the magnetic core of the present invention is much higher than those of the Mn-Zn ferrite and the Co-base amorphous alloy, meaning that the magnetic core of the present invention can be used for miniaturized transformers.

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WO2005114682A1 (de) * 2004-05-17 2005-12-01 Vacuumschmelze Gmbh & Co. Kg Stromwandlerkern sowie herstellverfahren für einen stromwandlerkern
DE19844132B4 (de) * 1997-09-26 2006-04-27 Hitachi Metals, Ltd. Magnetkern für eine sättigbare Drossel, Schaltregler mit mehreren Ausgängen vom Typ mit magnetischer Verstärkung sowie Computer mit einem derartigen Schaltregler
EP1188235B1 (de) * 1999-06-11 2006-05-10 Vacuumschmelze GmbH Hochpasszweig einer frequenzweiche für adsl-systeme
WO2007042649A1 (fr) * 2005-10-13 2007-04-19 Centre National De La Recherche Scientifique - Cnrs Procede de fabrication d'un capteur a magneto-impedance
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US7541909B2 (en) * 2002-02-08 2009-06-02 Metglas, Inc. Filter circuit having an Fe-based core
US8287664B2 (en) 2006-07-12 2012-10-16 Vacuumschmelze Gmbh & Co. Kg Method for the production of magnet cores, magnet core and inductive component with a magnet core
EP3050977A1 (de) * 2013-09-27 2016-08-03 Hitachi Metals, Ltd. Verfahren zur herstellung einer eisenbasierten nanokristallinen legierung und verfahren zur herstellung eines magnetischen kerns für die eisenbasierte nanokristalline legierung
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DE3911480A1 (de) * 1989-04-08 1990-10-11 Vacuumschmelze Gmbh Verwendung einer feinkristallinen eisen-basislegierung als magnetwerkstoff fuer fehlerstrom-schutzschalter
DE4108802A1 (de) * 1991-03-18 1992-09-24 Vacuumschmelze Gmbh Messwandler fuer elektronische anordnungen zur schnellen erkennung von kurzschluessen
JP2922844B2 (ja) * 1996-04-19 1999-07-26 日立金属株式会社 インバータを用いた装置
US6420813B1 (en) * 1998-11-06 2002-07-16 Alliedsignal Inc. Bulk amorphous metal magnetic components for electric motors
DE19908374B4 (de) * 1999-02-26 2004-11-18 Magnequench Gmbh Teilchenverbundwerkstoff aus einer thermoplastischen Kunststoffmatrix mit eingelagertem weichmagnetischen Material, Verfahren zur Herstellung eines solchen Verbundkörpers, sowie dessen Verwendung
KR100370061B1 (ko) * 2000-03-22 2003-01-29 엘지전자 주식회사 인덕터 및 그 제조방법
DE10045705A1 (de) * 2000-09-15 2002-04-04 Vacuumschmelze Gmbh & Co Kg Magnetkern für einen Transduktorregler und Verwendung von Transduktorreglern sowie Verfahren zur Herstellung von Magnetkernen für Transduktorregler
JP2002134329A (ja) * 2000-10-24 2002-05-10 Hitachi Metals Ltd 信号回線のコモンモード雷サージ電流抑制用磁性部品
DE102005034486A1 (de) 2005-07-20 2007-02-01 Vacuumschmelze Gmbh & Co. Kg Verfahren zur Herstellung eines weichmagnetischen Kerns für Generatoren sowie Generator mit einem derartigen Kern
JP2007027790A (ja) * 2006-09-29 2007-02-01 Toshiba Corp 磁心の製造方法および磁性部品の製造方法
US7909945B2 (en) 2006-10-30 2011-03-22 Vacuumschmelze Gmbh & Co. Kg Soft magnetic iron-cobalt-based alloy and method for its production
US9057115B2 (en) 2007-07-27 2015-06-16 Vacuumschmelze Gmbh & Co. Kg Soft magnetic iron-cobalt-based alloy and process for manufacturing it
US8012270B2 (en) 2007-07-27 2011-09-06 Vacuumschmelze Gmbh & Co. Kg Soft magnetic iron/cobalt/chromium-based alloy and process for manufacturing it
JP5267201B2 (ja) * 2009-02-23 2013-08-21 日産自動車株式会社 スイッチング回路
JP7195445B2 (ja) * 2019-08-22 2022-12-23 三菱電機株式会社 コアの冷却構造およびそれを備えた電力変換装置

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EP0392202A3 (de) * 1989-04-08 1991-04-03 Vacuumschmelze GmbH Verwendung einer feinkristallinen Eisen-Basis-Legierung als Magnetkernmaterial für einen Schnittstellen-Übertrager
US5074932A (en) * 1989-04-08 1991-12-24 Vacuumschmelze Gmbh Fine-crystalline iron-based alloy core for an interface transformer
EP0392202A2 (de) * 1989-04-08 1990-10-17 Vacuumschmelze GmbH Verwendung einer feinkristallinen Eisen-Basis-Legierung als Magnetkernmaterial für einen Schnittstellen-Übertrager
WO1994014080A3 (fr) * 1992-12-17 1994-10-13 Commissariat Energie Atomique Procede de determination de la permeabilite magnetique intrinseque d'elements ferromagnetiques allonges et des proprietes electromagnetiques de composites utilisant de tels elements
EP0687134A3 (de) * 1994-06-10 1996-03-13 Hitachi Metals Ltd Miniaturizierte Wandler- und Umrichterschaltung und Schaltung für eine Entladungslampe mit solch einem Transformator
EP0801443A1 (de) * 1996-04-12 1997-10-15 Vacuumschmelze GmbH Dämpfungseinrichtung gegen Störströme elektronischer Komponenten
DE19844132B4 (de) * 1997-09-26 2006-04-27 Hitachi Metals, Ltd. Magnetkern für eine sättigbare Drossel, Schaltregler mit mehreren Ausgängen vom Typ mit magnetischer Verstärkung sowie Computer mit einem derartigen Schaltregler
EP0921541A1 (de) * 1997-12-04 1999-06-09 Mecagis Herstellungsverfahren für einen nanokristallinen weichmagnetischen Kern für Anwendung in einem Differentialschützschalter
FR2772181A1 (fr) * 1997-12-04 1999-06-11 Mecagis Procede de fabrication d'un noyau magnetique en alliage magnetique doux nanocristallin utilisable dans un disjoncteur differentiel de la classe a et noyau magnetique obtenu
FR2772182A1 (fr) * 1997-12-04 1999-06-11 Mecagis Procede de fabrication d'un noyau magnetique en alliage magnetique doux nanocristallin et utilisation dans un disjoncteur differentiel de la classe ac
EP0921540A1 (de) * 1997-12-04 1999-06-09 Mecagis Herstellungsverfahren für einen Magnetkern aus einer weichmagnetischen nanokristallinen Legierung und Anwendung in einem Differentialschutzschalter
EP1188235B1 (de) * 1999-06-11 2006-05-10 Vacuumschmelze GmbH Hochpasszweig einer frequenzweiche für adsl-systeme
WO2003007316A3 (de) * 2001-07-13 2003-06-05 Vaccumschmelze Gmbh & Co Kg Verfahren zur herstellung von nanokristallinen magnetkernen sowie vorrichtung zur durchführung des verfahrens
US7563331B2 (en) 2001-07-13 2009-07-21 Vacuumschmelze Gmbh & Co. Kg Method for producing nanocrystalline magnet cores, and device for carrying out said method
US7541909B2 (en) * 2002-02-08 2009-06-02 Metglas, Inc. Filter circuit having an Fe-based core
US7358844B2 (en) 2004-05-17 2008-04-15 Vacuumschmelze Gmbh & Co. Kg Current transformer core and method for producing a current transformer core
WO2005114682A1 (de) * 2004-05-17 2005-12-01 Vacuumschmelze Gmbh & Co. Kg Stromwandlerkern sowie herstellverfahren für einen stromwandlerkern
US7861403B2 (en) 2004-05-17 2011-01-04 Vacuumschmelze Gmbh & Co. Kg Current transformer cores formed from magnetic iron-based alloy including final crystalline particles and method for producing same
WO2007042649A1 (fr) * 2005-10-13 2007-04-19 Centre National De La Recherche Scientifique - Cnrs Procede de fabrication d'un capteur a magneto-impedance
WO2007106024A1 (en) * 2006-03-10 2007-09-20 Abb Ab A measuring device including a layer of a magnetoelastic alloy and a method for production thereof
CN101416036B (zh) * 2006-03-10 2010-12-01 Abb公司 包含磁弹性合金层的测量装置及其制造方法
US8316724B2 (en) 2006-03-10 2012-11-27 Abb, Ab Measuring device including a layer of a magnetoelastic alloy and a method for production thereof
US8287664B2 (en) 2006-07-12 2012-10-16 Vacuumschmelze Gmbh & Co. Kg Method for the production of magnet cores, magnet core and inductive component with a magnet core
EP3050977A1 (de) * 2013-09-27 2016-08-03 Hitachi Metals, Ltd. Verfahren zur herstellung einer eisenbasierten nanokristallinen legierung und verfahren zur herstellung eines magnetischen kerns für die eisenbasierte nanokristalline legierung
EP3050977A4 (de) * 2013-09-27 2017-05-31 Hitachi Metals, Ltd. Verfahren zur herstellung einer eisenbasierten nanokristallinen legierung und verfahren zur herstellung eines magnetischen kerns für die eisenbasierte nanokristalline legierung
CN108559906A (zh) * 2017-12-11 2018-09-21 安徽宝辰机电设备科技有限公司 一种逆变焊机主变压器用铁芯材料
CN114649127A (zh) * 2018-04-27 2022-06-21 精工爱普生株式会社 软磁粉、压粉磁芯、磁性元件以及电子设备

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KR910002375B1 (ko) 1991-04-20
DE3884491D1 (de) 1993-11-04
EP0299498B1 (de) 1993-09-29
KR890002910A (ko) 1989-04-11
JPH0277105A (ja) 1990-03-16
DE3884491T2 (de) 1994-02-17
JPH0777167B2 (ja) 1995-08-16
CA1341105C (en) 2000-10-03

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