KR20140014188A - Alloy, magnetic core and process for the production of a tape from an alloy - Google Patents

Abstract

Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z and 1 at% or less of impurities, M is one or more of the elements Mo, Ta or Zr, and T is the element V, Mn At least one of Cr, Co, or Ni, and Z is at least one of the elements C, P, or Ge, 0 at% ≦ a <1.5 at%, 0 at% ≦ b <2 at%, 0 at% ≦ (b + c) alloys with <2 at%, 0 at% ≤d <5 at%, 10 at% <x <18 at%, 5 at% <y <11 at% and 0 at% ≤z <2 at% Is provided. The alloy consists of a tape, in which at least 50 vol% of the particles have a nanocrystalline structure with an average particle size of less than 100 nm, a hysteresis loop with a central linear region, and a residual magnetic ratio of less than 0.1 (J _r / J _s ) And a ratio of anti-magnetic field strength (H _c ) to anisotropic magnetic field strength (H _a ) of less than 10%.

Description

ALLOY, MAGNETIC CORE AND PROCESS FOR THE PRODUCTION OF A TAPE FROM AN ALLOY

The present invention relates to alloys, and more particularly, to a soft magnetic alloy suitable for use with a magnetic core, a magnetic core and a method for producing a tape from the alloy.

Nanocrystalline alloys based on Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z compositions can be used magnetically in various applications. US 7,583,173 is used in current transformers among the applications and consists of (Fe _1-a Ni _a ) _100-xyzabc Cu _x Si _y B _z Nb _α M ' _β M'' _γ , where a≤0.3, 0.6≤x≤1.5, 10 ≤ y ≤ 17, 5 ≤ z ≤ 14, 2 ≤ α ≤ 6, β ≤ 7, γ ≤ 8, M 'is at least one of the elements V, Cr, Al and Zn, M''is the element C, Ge A wound magnetic core is disclosed that is at least one of P, Ga, Sb, In, and Be.

EP 0 271 657 A2 also discloses alloys based on similar compositions.

These alloys, which are also in the form of tapes, can be used as magnetic cores of various components such as transformers, current transformers and storage chokes.

In general, it is desirable for magnetic core applications to achieve the lowest possible manufacturing cost. However, these cost reductions should, if possible, have little or no impact on the function of the core.

In some magnetic applications it is desirable to further reduce the size and weight of the magnetic core in order to further reduce the size and weight of the component itself. At the same time, however, no increase in manufacturing cost is desirable.

It is therefore an object of the present invention to provide an alloy that can be manufactured more cost-effectively and that is suitable for use on its own. Another object of the present invention is to select the alloy to be used in such a way that the size and / or weight of the magnetic core can be reduced compared to conventional magnetic cores.

This object is achieved by the subject matter of the independent claim. Further improvements are described in detail in the dependent claims.

The present invention _discloses an alloy composed of Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z and impurities of 1 at% or less. M is at least one of the elements Mo, Ta, and Zr, T is at least one of the elements V, Mn, Cr, Co, and Ni, Z is at least one of the elements C, P, and Ge, 0 at% ≦ a ≦ 1.5 at%, 0 at% ≤b≤2 at%, 0 at% ≤ (b + c) ≤2 at%, 0 at% ≤d≤5 at%, 10 at% ≤x≤18 at%, 5 at% ≤ y ≤ 11 at%, 0 at% ≤ z ≤ 2 at%. In addition, the alloy is in the form of a tape and includes nanocrystalline structures in which at least 50 vol% of the particles have an average particle size of less than 100 nm. The alloy also includes a hysteresis loop with a central linear region, a residual magnetic ratio (J _r / J _s ) of less than 0.1, and a ratio of antimagnetic strength (H _c ) to anisotropic magnetic strength (H _a ) of less than 10%. do.

The alloy has a composition with a niobium content of less than 2 at%. Since niobium is a relatively expensive element, it has the advantage of lower raw material costs than compositions with higher niobium content. In addition, the lower limit silicon content and the upper limit boron content of the alloy can be produced in the form of a tape under the tensile stress in the continuous furnace (continuous furnace), thereby setting to realize the above-described magnetic properties. It is therefore possible to use this manufacturing method to ensure that the alloy has the soft magnetic properties desirable for magnetic core applications despite the low niobium content.

The tape form not only allows the alloy to be produced under tensile stress in a continuous furnace, but also allows the magnetic core to be produced at any number of turns. Therefore, the size and magnetic properties of the magnetic core can be adjusted to the application by appropriately selecting the number of turns. Nanocrystalline structures with particle sizes less than 100 nm at least 50 vol% in the alloy result in low saturation magnetostriction at high saturation polarization. By selecting the appropriate alloy, a hysteresis loop having a central linear region, a residual magnetic ratio of less than 0.1, and an antimagnetic strength of less than 10% of the anisotropic magnetic field are obtained by heat treatment under tensile stress. It also has low hysteresis losses and permeability values that are largely independent of the applied magnetic field and / or premagnetization in the linear central region of the hysteresis loop, which is desirable for applications such as current transformers, transformers and storage chokes.

For the purposes of the present invention, the central region of the hysteresis loop is defined as the region of the hysteresis loop located between the points of the anisotropic magnetic field strength that characterize the transition to saturation. Similarly, the linear region of the central region of this hysteresis loop is defined by less than 3% nonlinearity factor (NL), which is calculated by the following equation.

NL (%) = 100 (δJ _up + δJ _down ) / (2J _s ) (1)

Where δJ _up and δJ _down are the norm of magnetization from the optimal line passing through the up or down branch of the hysteresis loop located between ± 75% of the magnetization values of the saturation polarization (J _s ) Deviation.

The alloy is therefore particularly suitable for magnetic cores, which are smaller and lighter, have lower raw material costs and have soft magnetic properties which are desirable for use with magnetic cores.

In one embodiment, the residual magnetic ratio of the alloy is less than 0.05. The hysteresis loop of the alloy is thus much more linear or monotonous. In another embodiment, the ratio of magnetic field strength to anisotropic magnetic field strength is less than 5%. Even in this embodiment, the hysteresis loop is much more linear, and thus the hysteresis loss is much lower.

In one embodiment, the alloy has a magnetic permeability (μ) of 40 to 3000 or 80 to 1500. In another embodiment, the alloy has a permeability between approximately 200 and 900. In these and other examples, the permeability is mainly determined by setting the tensile stress during the heat treatment. In this case, the tensile stress may be about 800 MPa or less without breaking the taper. Thus, it is possible to coat a tape having a permeability within the total permeability range of μ = 40 to approximately μ = 10000 with the desired composition. This results in a loop that is particularly linear in the region of low permeability, ie approximately μ = 40 to 3000.

This relatively low permeability is advantageous for applications such as current transformers, transformers, choking coils, etc., where the ferromagnetic saturation of the magnetic core needs to be prevented to prevent induction losses when high currents pass through the coil around the magnetic core.

Appropriate permeability ranges vary depending on the specific requirements of the various applications. Suitable ranges are 1500 to 3000, 200 to 1500 and 50 to 200. For example, a magnetic permeability μ of approximately 1500 to approximately 3000 is advantageous for DC current transformers, a magnetic permeability range of approximately 200 to 1500 is particularly suitable for transformers, and a magnetic permeability range of approximately 50 to 200 is particularly suitable for storage chokes.

The lower the permeability, the higher the current through the winding of the core can be without saturating the material. Similarly, at the same permeability, the higher the saturation polarization (J _s ) of the material, the higher the corresponding current. In contrast, magnetic induction increases proportionally with permeability and magnitude. Therefore, in order to construct a magnetic core having high inductance and high current tolerance, it is advantageous to use an alloy having a higher saturation polarization level. In one embodiment, the saturation polarization increases by reducing the niobium content, for example from J _s = 1.21 T to J _s = 1.34 T, ie more than 10%. This can be used to reduce the size and weight of the magnetic core without loss.

The alloy may have a saturation magnetostriction in terms of amount less than 5 ppm. Alloys with a saturation magnetostriction below this limit have particularly good soft magnetic properties, even when internal stresses are present, especially when the permeability is not significantly higher than 500. At higher permeability, it is advantageous to choose an alloy with lower saturation magnetostriction.

The alloy may also have a quantitative saturation magnetostriction of less than 2 ppm, preferably less than 1 ppm. Alloys with a saturation magnetostriction below this limit have particularly good soft magnetic properties, even when internal stresses are present, especially when the permeability (μ) is higher than 500 or higher than 1000.

In one embodiment, the alloy does not contain niobium. That is, b = 0. This embodiment has the advantage that the raw material cost is further reduced because niobium is completely excluded.

In further embodiments, the alloy does not contain copper. That is, a = 0. In a further embodiment, the alloy does not contain niobium and copper. That is, a = 0 and b = 0.

In a further embodiment, the alloy comprises niobium and / or copper, where 0 <a ≦ 0.5 and 0 <b ≦ 0.5.

In a further embodiment, the silicon and / or boron content is also determined, the alloy comprising 14 at% <x <17 at% and / or 5.5 at% <y <8 at%.

As already mentioned above, the alloy takes the form of a tape. The tape may have a thickness of 10 μm to 50 μm. This thickness allows the magnetic core to be wound with a high number of windings and to have a small outer diameter.

In further examples, at least 70 vol% of the particles have an average particle size of less than 50 nm. This may further improve the magnetic properties.

The alloy is heat treated in tape form under tensile stress to produce the desired magnetic properties. Therefore, the alloy, i.e., the finished tape after heat treatment, is also characterized by the structure produced by this manufacturing method. In one embodiment, the crystals have an average size of approximately 20 nm to 25 nm and have a residual elongation between approximately 0.02% and 0.5% proportional to the applied tensile stress during heat treatment along the tape. For example, an elongation of approximately 0.1% is obtained due to heat treatment under a tensile stress of 100 MPa.

The grains may have an elongation of at least 0.02% in the preferred direction.

Magnetic cores made of an alloy as disclosed in one of the above embodiments are also provided. The magnetic core may take the form of a wound tape, in which case the tape may be wound on one side or wound as a cylindrical coil about an axis to form a magnetic core according to the application.

The tape of the magnetic core may be coated with an insulating film to electrically insulate the windings of the magnetic core from each other. The film may be, for example, a polymer film or a ceramic film. The tape may be coated with an insulating layer before and / or after winding up to form a magnetic core.

As already mentioned, the magnetic cores disclosed in one of the above embodiments can be used for various components. Magnetic core transformers, current transformers and storage chokes as disclosed in one of these embodiments are also provided.

The method of making the tape consists of Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z and impurities up to 1 at%, M is one or more of the elements Mo, Ta and Zr, and T Is at least one of the elements V, Mn, Cr, Co, and Ni, Z is at least one of the elements C, P, and Ge, 0 at% ≤a <1.5 at%, 0 at% ≤b <2 at%, 0 at% ≦ (b + c) <2 at%, 0 at% ≦ d <5 at%, 10 at% <x <18 at%, 5 at% <y <11 at% and 0 at% ≦ z < Producing a tape made of an amorphous alloy having a composition of 2 at%. The tape is heat treated under tensile stress in a continuous furnace at _a predetermined temperature (T _a ) of 450 ° C. ≦ T _a ≦ 750 ° C.

The composition can be prepared to have magnetic properties suitable for magnetic use by heat treatment between 450 ° C. and 750 ° C. under tensile stress. The heat treatment results in nanocrystalline structures having an average particle size of at least 50 vol% of the particles below 100 nm. In particular, the method includes a hysteresis loop with a central linear region, a residual magnetic ratio (J _r / J _s ) of less than 0.1, and a ratio of anti-magnetic field strength (H _c ) to anisotropic magnetic field strength (H _a ) of less than 10%. It can be used to prepare the present compositions comprising less than 2 at% niobium to obtain.

The tape is continuously heat treated. As a result, the tape passes through the continuous furnace at a predetermined speed s. (S) the speed may be set so that the tape between the temperature (T _a) 5% to successive temperature zones having a temperature of less than (temperature zone) in a time length of 2 seconds to send a half of the. The length of time required for heating the tape up to the temperature T _a in this method is approximately the length of the heat treatment itself. The same applies to the length of the subsequent cooling period. The heat treatment for this length of time in this annealing temperature range achieves the desired structure and desirable magnetic properties.

In one embodiment, the tape passes through the furnace under tensile stress between 5 MPa and 160 MPa. In a further embodiment, the tape passes through the furnace under a tensile stress of 20 MPa to 500 MPa. It is also possible to pass the tape through the oven at high tensile stresses of approximately 800 MPa or less without breaking the tape. This tensile stress range is suitable for realizing desirable magnetic properties having the aforementioned components.

를 만족하는 인장 응력(σ_a)이 열처리 중에 요구된다. 일 실시예에서, α는

MPa의 값을 가진다. 다른 실시예에서, α는 예컨대

MPa의 값을 가진다. 따라서

MPa 내지

MPa 범위의 값이 본 발명에 개시된 합금과 대응하는 열처리 공정에 사용될 수 있다. α의 정확한 값은 각각의 경우 조성물, 어닐링 온도 및 어느 정도는 어닐링 시간에 따라 달라진다.The value of the permeability μ realized is inversely proportional to the tensile stress σ _a applied during the heat treatment. Therefore, in order to realize a predetermined relative permeability value (μ)

Tensile stress σ _a that satisfies is required during the heat treatment. In one embodiment, α is

It has a value of MPa. In other embodiments, α is for example

It has a value of MPa. therefore

MPa to

Values in the MPa range can be used in the corresponding heat treatment processes with the alloys disclosed herein. The exact value of α depends in each case on the composition, the annealing temperature and to some extent the annealing time.

에 따른 인장 응력(σ_Test) 하에서의 시험 어닐링 공정의 투자율(μ_Test)로부터 선택된다.The tensile stresses that result in the desired magnetic properties can therefore depend on the composition and the annealing temperature of the alloy as well as the annealing time. In one embodiment, the tensile stress σ _a required for a given permeability μ is calculated by

Tensile stress is selected from the magnetic permeability (μ _Test) in the annealing process under test _(Test σ) according to the.

Preferred magnetic properties can vary depending on the annealing temperature T _a and can therefore be set by selecting the annealing temperature. In one embodiment, the temperature T _a is selected according to the niobium content (b) according to the formula (T _x1 + 50 ° C.) ≦ T _a ≦ (T _x2 + 30 ° C.). Where T _x1 and T _x2 correspond to the crystallization temperature determined by the maximum transformation heat and are determined by standard thermal analysis methods such as differential scanning calorimetry (DSC) at a heating rate of 10 K / min.

In further embodiments, the desired permeability or anisotropic magnetic field strength value and the allowable deviation range are predetermined. To achieve this value along the length of the tape, the magnetic properties of the tape are continuously measured as the tape leaves the furnace. If deviation from the allowable deviation range is observed, the tensile stress of the tape is adjusted to return the measurement of the magnetic properties to within the allowable deviation range.

This embodiment reduces the variation in magnetic properties along the length of the tape, thereby making the magnetic properties within the magnetic core more homogeneous and / or reducing the variation in the magnetic properties of the plurality of magnetic cores made from the tape. It is therefore possible to improve the regularity of the soft magnetic properties of magnetic cores, especially in commercial production.

)으로 열처리 후 합금 Fe₇₆Cu_{0 .5}Nb_{1 .5}Si_{15 .5}B_6.5의 자기 특성을 도시한다.
표 5는 제조 상태에서 측정된 포화 분극 레벨(J_s)과, 상이한 합금 조성물의 열처리 후 상이한 어닐링 온도(T_a)에서 측정된 비선형성(NL), 잔류자기 비(J_r/J_s), 항자계 강도(H_c), 이방성 자계 강도(H_a) 및 상대 투자율(μ) 값을 도시한다.
표 6은 제조 상태에서 측정된 포화 분극 레벨(J_s)과, 상이한 합금 조성물의 열처리 후 측정된 비선형성(NL), 잔류자기 비(J_r/J_s), 항자계 강도(H_c), 이방성 자계 강도(H_a) 및 상대 투자율(μ) 값을 도시한다.
표 7은 제조 상태에서 측정된 상이한 합금 조성물의 포화 자왜(

)와, 지정된 어닐링 온도(T_a)에서 응력 하의 열처리 후 측정된 상이한 합금 조성물의 포화 자왜(

)를 도시한다.Hereinafter, the embodiments will be described in more detail with reference to the following examples, tables and drawings.
1 is a chart showing the hysteresis loop of a comparative example of nanocrystalline Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 having different niobium contents after heat treatment in a magnetic field perpendicular to the length of the tape.
FIG. 2 is a diagram showing the hysteresis loop of nanocrystalline Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 after heat treatment under tensile stress applied along the length of the tape for different niobium contents.
3 is a graph showing the residual magnetic ratio of nanocrystalline Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _{6.5 with} Nb content after heat treatment in a magnetic field and after heat treatment under tensile stress.
4 is a graph showing the saturation polarization of Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 according to the Nb content.
5 shows the saturation magnetostriction (λ _s ), anisotropic magnetic field (H _a ), antimagnetic field strength (H _c ), residual magnetic ratio (J) of Fe _75.5 Cu ₁ Nb _1.5 Si _15.5 B _6.5 after heat treatment under tensile stress at different annealing temperatures. _r / J _s ) and nonlinear factor (NL).
6 is a graph showing the residual magnetic ratio (J _t / J _s ) and the magnetic field strength (H _c ) of the alloy Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 after heat treatment under tensile stress.
7 shows the definition of crystalline behavior and crystallization temperatures (Tx1, Tx2) of alloy Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 measured using differential scanning calorimetry (DSC) at a heating rate of 10 K / min. .
Figure 8 is an alloy Fe ₇₇ Cu ₁ Si ₁₅ in the amorphous state from _0.5 B _6.5, and a different crystallization different annealing temperatures and stresses alloy Fe ₇₇ Cu ₁ Si ₁₅ B _6.5 after heat treatment under _0.5 shows the X-ray diffraction chart of the stages do.
Figure 9 after heat treatment under certain tensile stress (σ _a) Nanocrystalline _{Fe 75 .5 Cu 1 Nb 1 .5} Si 15 .5 B 6.5 of the permeability (μ), the anisotropic magnetic field (H _a), wherein the magnetic field strength (H _c ), Residual magnetic ratio (J _r / J _s ) and nonlinearity factor (NL).
FIG. 10 shows the lower and upper optimum annealing temperatures T _a1 , T _a2 according to the crystallization temperatures T _x1 , T _x2 for different alloy compositions.
11 is a chart showing the anti-magnetic strength (H _c ) and residual magnetic ratio (J _r / J _s ) of the alloy Fe ₈₀ Si ₁₁ B ₉ and the comparative composition Fe _78.5 Si ₁₀ B _11.5 after heat treatment under tensile stress.
12 is a plot showing the hysteresis loop of alloy Fe ₈₀ Si ₁₁ B ₉ and comparative composition Fe _78.5 Si ₁₀ B _11.5 after heat treatment under different tensile stresses.
13 is a schematic view of a continuous furnace.
Table 1 shows the nonlinearity factors of the alloys Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 for different Nb contents after heat treatment in the magnetic field (comparative example) and after heat treatment under mechanical stress (method according to the invention) _. Illustrated.
Table 2 shows the measured annealing temperature and the appropriate annealing temperature (T _a ) for annealing times of approximately 2 to 10 seconds for different Nb contents of alloy Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 .
Table 3 is substantially under a tensile stress of 120 MPa in a 610 ℃ of continuous heat treatment after the alloy Fe ₇₆ Cu ₁ Nb ₁ in accordance with the annealing time (T _{a) .5} Si _{13 .5} shows the magnetic properties of the B _8.
Table 4 shows the specific tensile stresses (

) After the heat treatment of an alloy _{Fe 76 Cu 0 .5 Nb 1 .5} Si 15 .5 B 6.5 of the magnetic The characteristic is shown.
Table 5 shows the saturation polarization level (J _s ) measured in the manufacturing state, nonlinearity (NL), residual magnetic ratio (J _r / J _s ), measured at different annealing temperatures (T _a ) after heat treatment of different alloy compositions, The magnetic field strength (H _c ), anisotropic magnetic field strength (H _a ), and relative magnetic permeability (μ) values are shown.
Table 6 shows the saturation polarization level (J _s ) measured in the manufacturing state, nonlinearity (NL), residual magnetic ratio (J _r / J _s ), antimagnetic field strength (H _c ), measured after heat treatment of different alloy compositions, Anisotropic magnetic field strength (H _a ) and relative permeability (μ) values are shown.
Table 7 shows the saturation magnetostriction of the different alloy compositions measured

) And the saturation magnetostriction of different alloy compositions measured after heat treatment under stress at the specified annealing temperature (T _a )

).

1 is a diagram showing a hysteresis curve of a tape-shaped nanocrystalline alloy.

The test was carried out, for example, on metal tapes having a width of 6 mm and 10 mm and usually of 17 μm to 25 μm thickness. However, the spirit of the present invention is not limited to these dimensions.

The tape has a composition of Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 . The hysteresis loop is measured after the heat treatment in the magnetic field, which is performed for 0.5 hours at 540 ° C. in a magnetic field of H = 200 kA / m perpendicular to the length of the tape. 1 shows that the hysteresis loop becomes more and more nonlinear as the Nb content decreases. This nonlinear hysteresis loop is undesirable for some magnetic core applications because of the increased losses due to hysteresis.

Table 1 shows the nonlinearity factor (NL) of the hysteresis loop shown in FIGS. 1 and 2 for different heat treatments and different Nb contents. In particular, Table 1 shows nanocrystalline Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B according to different Nb content after heat treatment in magnetic field at 540 ° C. for 0.5 hour and heat treatment under tensile stress of 100 MPa for 4 seconds at 600 ° C. The nonlinearity factor of _6.5 is shown.

3 is a graph showing the residual magnetic ratio (J _r / J _s ) of the heat-treated sample according to the Nb content. In particular, FIG. 3 shows nanocrystalline Fe _{77 - x} Cu ₁ Nb according to the Nb content after heat treatment in a magnetic field for 0.5 hours at a temperature of 480 ° C. to 540 ° C. and after heat treatment under a tensile stress of 4 seconds at a temperature between 520 ° C. and 700 ° C. The residual magnetic ratio of _x Si _{15 .5} B _6.5 is shown.

In the case of heat treatment in the magnetic field as indicated by the white circle in Fig. 3, a particularly linear loop having a residual magnetic ratio of less than 0.1 and a nonlinearity factor of less than 3% is reliably obtained only when the Nb content is higher than 2 at%. do. In contrast, in the case of heat treatment under tensile stress, linear loops having a residual magnetic ratio of less than 0.1 and a nonlinearity of less than 3% can be reliably obtained even when the Nb content is less than 2 at% and the composition does not contain niobium. Can be.

The results shown in FIGS. 1 and 3 show that if the heat treatment is carried out in a magnetic field, a minimum Nb content, preferably above 2 at%, is required to produce a tape having magnetic properties suitable for use with magnetic core.

Tables 1-6 and FIGS. 2-12 show that a linear loop with a small residual magnetic ratio can be obtained in a composition with a niobium content of less than 2 at% if the heat treatment is done under mechanical tensile stress along the tape. Since niobium is a relatively expensive element, this composition has the advantage that the raw material cost is reduced.

2 is a diagram showing the hysteresis loop after heat treatment in a continuous furnace for an effective annealing time of 4 seconds under a temperature of 600 ° C. and a tensile stress of approximately 100 MPa.

Annealing time in a continuous furnace is defined as the period of time that the tape passes through a temperature zone whose temperature is within 5% of the annealing temperature specified herein. The length of time needed to heat the tape up to the annealing temperature is approximately the length of the heat treatment itself.

2 shows that it is possible to obtain a hysteresis loop with a central linear region and a small residual magnetic ratio when the Nb content is less than 2 at%. A composition comprising 3 at% Nb is a comparative example and a composition with Nb <2 at% is an example according to the invention. The arrow shows the definition of the anisotropy field strength (H _a) as an example.

3 is a chart comparing the residual magnetic ratio according to the Nb content of a tempered sample under tensile stress as indicated by the black diamond of FIG. 3 with the Nb content of the tempered sample in a magnetic field as indicated by white color. . Alloys with an Nb content of less than 2 at% have a small residual magnetic ratio of less than 0.05 only when tempered under tensile stress. However, when these compositions are tempered in a magnetic field, the residual magnetic ratio is markedly high, so such alloys are undesirable for some magnetic core applications. Alloy Fe ₇₇ Cu ₁ Si and results in a _{5 .5} B _6.6, i.e. remanence ratio of less than 0.05 substantially linear loop when heat-treated under a tensile stress, even alloys which do not contain an addition of Nb.

4 is a diagram showing the saturation polarization according to the Nb content of the alloy having a composition of Fe _{77 - x} Cu ₁ Nb _x Si _{15 .5} B _6.5 . Alloys with reduced Nb content have significantly higher saturation polarization. This can advantageously be used to reduce both weight and material costs. In addition to the reduction of the raw material cost, it provides an additional advantage that the apparatus including the magnetic core can be miniaturized.

FIG. 5 shows the saturation magnetostriction (λ _s ), anisotropic magnetic field (H _a ), and anti-magnetic field strength ( _A ) according to the annealing temperature of the composition Fe _75.5 Cu ₁ Nb _1.5 Sil _15.5 B _6.5 after heat treatment for approximately 4 seconds under a tensile stress of approximately 50 MPa. H _c ), residual magnetic ratio (J _r / J _s ) and nonlinearity factor (NL). 2, the anisotropic magnetic field (H _a) corresponds to the magnetic field is a linear region of the hysteresis loop is saturated.

As shown by the hatched in the diagram, the range of annealing temperatures at which the desired properties can be realized is approximately 535 ° C to 670 ° C.

Hatched regions show regions of the linear loop with low saturation magnetostriction, high anisotropic magnetic field and low residual magnetic ratio. This is also the area where the alloy has a particularly linear loop. Thus the most suitable annealing temperature in the embodiment disclosed in FIG. 5 is between 535 ° C and 670 ° C.

These temperature limits are largely independent of the level of tensile stress. However, these temperature limits depend on the length of the heat treatment and the Nb content. Thus, as shown in FIG. 6 and Table 2, these temperature limits decrease as the Nb content decreases or the length of the heat treatment increases.

FIG. 6 illustrates annealing behavior of a niobium alloy variant where the optimum annealing temperature is in the range of approximately 500 ° C. to 570 ° C., ie, significantly lower than the optimum annealing temperature of the composition shown in FIG. 5. In particular, FIG. 6 shows the residual magnetic ratio (J _t / J _s ) and the magnetic field strength of the alloy Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 after heat treatment for 4 seconds at T _a = 613 ° C. under a tensile stress of approximately 50 MPa _. (H _c ) is a chart. The optimum annealing temperature disclosed herein is in the range of approximately 500 ° C to 570 ° C. As schematically shown in the inset, this provides a monotonous linear hysteresis loop with a residual magnetic ratio of less than 0.1.

FIG. 7 shows the crystallization behavior measured by differential scanning calorimetry (DSC) at an heating rate of 10 K / min using an example Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 of the alloy. 7 shows two crystallization steps characterized by crystallization temperatures T _x1 , T _x2 . The temperature range defined by T _x1 and T _x2 in the DSC measurement corresponds to the optimum annealing temperature range present between 500 ° C. and 570 ° C. for the alloy as shown in FIG. 6.

8 shows an X-ray diffraction diagram of alloy Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 in an amorphous initial state and alloy Fe after stress heat treatment at different annealing temperatures corresponding to different crystallization stages defined by T _x1 and T _x2 . X-ray diffractogram of ₇₇ Cu ₁ Si _{15 .5} B _6.5 is shown. In particular, FIG. 8 illustrates an annealing range of 515 ° C., i.e., an annealing range in which the magnetic properties disclosed herein are realized, and an undesirable annealing range, in which no linear hysteresis loop with 680 ° C., i. X-ray diffractograms are shown after heat treatment under stress at temperature for 4 seconds.

Maximum diffraction analysis shows that the only crystals formed into the crystalline phase at the annealing temperature resulting in linear hysteresis loops with low residual magnetic ratios are substantially cubic Fe-Si crystals embedded in an amorphous minority matrix. For alloy Fe ₇₇ Cu ₁ Si _{15 .5} B _6.5 , the average particle size of these crystals is in the range of approximately 38 nm to 44 nm. When the same analysis is carried out on the alloy composition Fe _{75. 5} Cu ₁ Nb ₁ Si _{15 .5} B _6.5 , the average crystal grain size realized by the corresponding optimum annealing temperature is in the range of 20 nm to 25 nm.

In the second crystallization stage, the boride phase crystallizes from the amorphous residual matrix, which has an undesirable effect on the magnetic properties and results in a nonlinear loop having a high residual magnetic ratio and high magnetic field strength.

Table 2 shows additional examples and additional data in the form of crystallization temperatures (T _x1 , T _x2 ) measured at 10 K / min by differential scanning calorimetry (DSC) corresponding to the crystallization of bcc-FeSi and boride, respectively. do. Appropriate annealing temperatures exist between approximately T _x1 and T _x2 , thereby obtaining a structure consisting of nanocrystalline particles with an average particle size of less than 50 nm embedded in an amorphous matrix and desirable magnetic properties.

However, T _x1 and T _{x2 ,} and The annealing temperature T _a depends on the heating rate and the length of the heat treatment. For this reason the optimum annealing temperature for heat treatments of less than 10 seconds is higher than the crystallization temperatures (T _x1 and T _x2 ) of Table 2 measured using differential scanning calorimetry (DSC) at 10 K / min. Thus the optimum annealing temperature (T _a ) for longer annealing times of 10 to 60 minutes is, for example, usually by 50 ° C. to 100 ° C. below the T _a value for the heat treatment of several seconds listed in Table 2.

Thus, the annealing temperature (T _a ) can be adapted to the length of the composition and the heat treatment as needed, as shown in FIG. 5, and using the crystallization temperatures according to Table 2 measured using differential scanning calorimetry. have.

Table 3 using the example of an alloy consisting of a composition _{Fe 76 Cu 1 Nb 1 .5 Si} 13 .5 B 8 shows the effect of annealing time. Annealing times in the range of seconds to minutes do not have a significant effect on the magnetic properties thus obtained. This is true as long as the annealing temperature (T _a ) is between the limit temperatures discussed in Table 2. In this example, the limit temperatures are T _x1 = 489 ° C and T _x2 = 630 ° C measured using differential scanning calorimetry at 10 K / min or T _a1 = 540 ° C and T _a2 for heat treatment lasting 4 seconds. = 640 ° C.

In this embodiment, the annealing temperature is T _a = 610 ° C., and thus falls between the upper and lower limits of the defined limit temperature. The crystallization temperature measured at a heating rate of 10 K / min generally corresponds to the optimum annealing range during the isothermal heat treatment lasting several minutes.

9 shows the correlation of permeability, anisotropic magnetic field, anti-magnetic field strength, residual magnetic ratio and nonlinearity factor to tensile stress applied during heat treatment. In particular, Figure 9 is a specific tensile stress (σ _a) and at a temperature of 613 ℃ after heat treatment for 4 seconds nanocrystalline _{Fe 75 .5 Cu 1 Nb 1 .5} Si 15 .5 B 6.5 permeability of an anisotropic magnetic field, wherein the magnetic field strength , Residual magnetic ratio and nonlinearity factor. In all cases, this typically resulted in residual magnetic ratios (J _r / J _s ) of less than 0.04 and nonlinearity factors of less than 2%.

Table 4 shows further examples of the correlation of magnetic permeability, anisotropic magnetic field, anti-magnetic field strength, residual magnetic ratio and nonlinear factor to tensile stress applied during heat treatment. In particular, the table shows the magnetic permeability, anisotropic magnetic field, antimagnetic strength, residual magnetic ratio and nonlinearity of nanocrystalline Fe ₇₆ Cu _0.5 Nb _1.5 Si _15.5 B _6.5 after heat treatment for 4 seconds at _a specific tensile stress (σ _a ) and at a temperature of 605 ° C. Table showing the arguments. In all cases, this usually resulted in residual magnetic ratios (J _r / J _s ) of less than 0.1 and nonlinearity factors of less than 3%.

또는

를 필요로 하는데, 여기서 μ₀=(4π 10^-7 Vs/(Am))는 자계 상수이다. α는 주로 합금의 조성에 따라 달라지지만 어닐링 온도와 어닐링 시간에 따라서도 달라지는 재료 파라미터를 가리킨다. 통상의 값은

MPa 내지

MPa의 범위 내에 존재한다. 특히 도 9에 도시된 예는

MPa의 값을 초래하고, 표 3에 도시된 예는

MPa의 값을 초래한다.9 and Table 4 show that the anisotropic magnetic field strength (H _a ) and the permeability (μ) can be accurately set by adjusting the tensile stress (σ _a ). The predetermined anisotropic magnetic field strength (H _a ) or permeability (μ) value is a tensile stress during heat treatment.

or

Where μ ₀ = (4π 10 ^-7 Vs / (Am)) is the magnetic field constant. α refers to a material parameter which mainly depends on the composition of the alloy but also depends on the annealing temperature and the annealing time. The usual value is

MPa to

It is in the range of MPa. In particular, the example shown in FIG.

Resulting in the value of MPa, the example shown in Table 3

Results in a value of MPa.

9 and Table 3 also show that the lower the permeability set, the greater the linearity of the loop. Thus, a permeability of less than approximately μ = 3000 results in a particularly linear loop with less than 2% nonlinearity and less than 0.05 residual magnetic ratio (J _r / J _s ).

The tape of the above embodiment includes an alloy having the following composition.

Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z ,

Cu 0≤a <1.5

Nb 0≤b <2

M is at least one of the elements Mo, Ta or Zr, 0 ≦ b + c <2,

T is at least one of the elements V, Cr, Co or Ni, 0≤d <2,

Si 10 <x <18

B 5 <y <11

Z is at least one of the elements C, P or Ge, 0 ≦ z <2,

The alloy contains up to 1 at% impurities. Typical impurities are C, P, S, Ti, Mn, Cr, Mo, Ni and Ta.

Under certain heat treatments, the composition can affect the magnetic properties. It is possible to control the heat treatment, in particular the tensile stress, in order to realize the desired magnetic properties of the given composition.

Table 5 shows an example of an alloy heat treated for approximately 4 seconds under an optimum annealing temperature (T _a ) and a tensile stress of 50 MPa for the corresponding composition and a comparative example having a composition in which the niobium content is above 2 at%. Another example numbered from 1 to 10 represents a composition disclosed herein having an Nb content of less than 2 at%. 10 also shows the optimum annealing temperature and crystallization temperature of the alloy examples (1 to 10). In particular, FIG. 10 shows the upper and lower optimum annealing temperatures T _a1 , T _a2 for a 4 second annealing time according to the crystallization temperatures T _x1 , T _x2 measured using DSC at 10 K / min.

These examples demonstrate that the composition of the alloys disclosed herein can vary within certain limits. Within the limits specified above, (1) elements such as Mo, Ta and / or Zr can be added to the alloy instead of Nb and (2) transition metals such as V, Mn, Cr, Co and / or Ni replace Fe May be added to the alloy and / or (3) elements such as C, P and / or Ge may be added to the alloy without significantly changing its properties. To further confirm this finding, in further embodiments, an alloy composition

_{Fe 71 .5 Co 2 .5 Ni 0} .5 Cr 0 .5 V 0 .5 Mn 0 .2 Cu 0 .7 Nb 0 .5 Mo 0 .5 Ta 0 .4 Si 15 .5 B 6.5 C 0. ₂ was made from a tape having a thickness of 20 μm and a width of 10 mm. The alloy has a saturation polarization of J _s = 1.25 T and reacts to the heat treatment under tensile stress, for example in a manner similar to the exemplary alloys of Table 3 (2-5). Thus, a nonlinearity factor of 0.4%, residual magnetic ratio of J _r / J _s = 0.01, term of H _c = 6 A / m, with a thermal stress of 50 MPa and a heat treatment lasting approximately 4 seconds at a temperature of 600 ° C. Magnetic field strength, anisotropic magnetic field of H _a = 855 A / m and permeability value of μ = 1160 are obtained.

Table 5 shows that the desired magnetic properties can be realized without adding Cu.

Thus, Table 6 shows additional exemplary alloys in which the Cu content is systematically altered and the heat treatment is performed for approximately 7 seconds at a tensile stress of approximately 15 MPa and a temperature of 600 ° C. In particular, in Table 6 Fe was phased out by Cu without changing other alloying components.

Table 6 shows that the Cu content does not significantly affect the magnetic properties when the Cu content is less than 1.5 at%. However, the addition of Cu promotes brittleness during the manufacture of the tape. In particular, alloys having a Cu content higher than 1.5 at% (such as alloy 15 in Table 6) show high brittleness in the prepared state. For example, the alloy _{Fe 74 .5 Cu 2 Nb 1 .5} Si 15 .5 20 ㎛ thickness of tape consisting of a _6.5 B may be cracking at the bending diameter of approximately 1 mm.

Due to the high tape speeds (25 m / s to 30 m / s) reached during manufacture, it is impossible or very difficult to capture the brittle tape during the casting process or wind the tape as soon as the tape leaves the cooling roller. This makes manufacturing tapes uneconomical. In addition, many of these tapes, which are brittle from the beginning, are cracked during heat treatment, especially before reaching higher temperature zones. If this crack occurs, the heat treatment process stops and the tape must pass through the oven again.

In contrast, alloys having a Cu content of less than 1.5 at% can be bent up to a bending diameter that is twice as large as the tape thickness without breaking, i.e. typically up to less than 0.06 mm. This allows the tape to be wound up immediately during casting. Also, the heat treatment of these tapes, which are soft from the beginning, is significantly simpler. Alloys with a Cu content of less than 1.5 at% are embrittled during heat treatment but only after cooling off the oven. Therefore, the possibility of cracking the tape during heat treatment is significantly lower. Also, in most cases the transport of the tape through the oven can continue despite cracking. Overall, tapes that are soft from the beginning can be manufactured and heat treated with little trouble and thus more economically.

The compositions shown in Tables 5 and 6 represent nominal compositions in units of at% corresponding to the concentrations of the individual elements found in chemical analysis, typically with an accuracy of ± 0.5 at%.

When manufactured under tensile stress, the silicon and boron contents also affect the magnetic properties of this type of nanocrystalline alloy with a niobium content of less than 2 at%.

The examples set forth in Tables 3 to 6 show a combination of the following preferred properties, namely a linear central region, a residual magnetic ratio (J _r / J _{s ) of} less than 0.1 and typically only the number of anisotropic magnetic field strengths (H _a ). It has a magnetization loop with low coercive field strength (H _c ) corresponding to a percentage.

Figure 11 and 12 compares the magnetic properties of the composition _0.5 Fe ₈₀ Si ₁₁ B ₉ and Fe _{78 .5} Si ₁₀ B _11. FIG. 11 is a chart showing the anti-magnetic strength (H _c ) and residual magnetic ratio (J _r / J _s ) curves according to the annealing temperature (T _a ) of the two alloys after heat treatment under a tensile stress of approximately 50 MPa. The magnetic field strength (H _c ) and the residual magnetic ratio (J _r / J) of the alloy Fe ₈₀ Si ₁₁ B ₉ disclosed in the present invention and indicated by the black circle and the comparative composition Fe _{78 .5} Si ₁₀ B _{11 .5 s} ) is shown after heat treatment for 4 seconds at _a predetermined annealing temperature (T _a ) under a tensile stress of approximately 50 MPa.

FIG. 12 is a chart showing the hysteresis loop of the two alloys after heat treatment for 4 seconds at a temperature of approximately 565 ° C. under tensile stress of 50 MPa (dashed line) and 220 MPa (solid line). The hysteresis loop of the alloy Fe ₈₀ Si ₁₁ B ₉ disclosed in the present invention is shown on the left, and the hysteresis loop of the comparative composition Fe _{78 .5} Si ₁₀ B _{11 .5} is shown on the right.

The alloys shown in FIGS. 11 and 12 differ only slightly in their chemical composition, but there are significant differences in the magnetic properties of the two alloys.

For example, after heat treatment at a temperature between approximately 530 ° C. and 570 ° C., the composition Fe ₈₀ Si ₁₁ B ₉ has a low residual magnetic ratio (J _r / J _{s ) of} less than 0.1 and significantly lower than 100 A / m and anisotropic magnetic field strength (H _a). It has a linear magnetization loop with low coercive field strength, which corresponds to only a few percent.

(도 11 참조)이다. 또한, 이 최저 J_r/J_s 값에서는 대략

의 불리하게 높은 항자계 강도가 존재한다. 따라서, 자화 루프의 중앙 영역은 선형성을 상실하며 이력 루프의 현저한 발산도로 인해 불리하게 높은 이력 손실이 초래된다(도 12 참조).In contrast, the composition Fe _{78 .5} Si ₁₀ B _{11 .5} has a high residual magnetic ratio over the entire heat treatment range. Even the lowest residual magnetic ratio realized at annealing temperatures between 540 ° C and 570 ° C

(See FIG. 11). Also, this lowest J _r / J _s The value is approximately

There is an unfavorable high magnetic field strength of. Thus, the central region of the magnetization loop loses linearity and results in an adversely high hysteresis loss due to the significant divergence of the hysteresis loop (see FIG. 12).

These examples show that alloy compositions having a Si content of more than 10 at% and a B content of less than 11 at% after heat treatment under tensile stress are significantly less than 0.1 and a residual magnetic ratio (J _r / J _s ) of less than 100 A / m. It is shown that this results in a monotonous, generally linear hysteresis loop with low coercive field strength, which is less than 10% of the low anisotropic magnetic field. If the silicon content is lower and the boron content is higher than these limits, the desired magnetic properties are not realized after this heat treatment under tensile stress.

The upper limit Si content and the lower limit B content are also investigated. (See Alloy 5 in Table 5), the alloy composition _{Fe 75 Cu 0.5 Nb 1.5 Si 17.5} B 5.5 was able to be prepared as an amorphous flexible tape Despite that the desired properties after heat treatment, an alloy composition Fe ₇₅ Cu _{0 .5} Nb _{1 .5} Si ₁₈ B ₅ is is showed a magnetic characteristic on the boundary line after the heat treated alloy composition _{Fe 75 Cu 0 .5 Nb 1 .5} Si 18 .5 B 4.5 could be made of a more ductile amorphous tape.

This example shows that an alloy composition having a Si content of less than 18 at% and a B content of more than 5 at% after heat treatment under tensile stress is significantly higher than a residual magnetic ratio (J _r / J _s ) of less than 0.1 and 100 A / m. It is shown that this results in a monotonous, generally linear hysteresis loop with low coercive field strength, which is less than 10% of the low anisotropic magnetic field. If the silicon content is higher than 18 at% and the boron content is less than 5 at%, heat treatment under such tensile stress does not realize the desired magnetic properties or an amorphous flexible tape can no longer be produced.

Table 7 given the saturation magnetostriction constant (λ _s) of a different alloy composition is determined in a manufacturing state annealing temperature (T _a) in the saturation magnetostrictive constant of a different alloy composition, measured after heat treatment for 4 under the 50 MPa stress early (λ _s ). In particular, in order to obtain particularly small magnetostrictive values for a given composition (see Table 5), the selected annealing temperature was less than 50 ° C. from the maximum possible annealing temperature (T _a2 ), which is ultimately determined by the composition of the alloy. do. The effect of the Si content is shown.

As a supplement to Table 7, Figure 5 demonstrates that the saturation magnetostriction is clearly reduced through heat treatment under tensile stress, thereby making the magnetic properties reproducible. In particular, due to low magnetostriction, mechanical stress has little or no effect on the hysteresis loop. This mechanical stress can occur when the heat-treated tape is wound around the core or when the core is embedded in a trough or plastic mass for protection or further wire coils are provided on the core during further processing. It can be used to devise particularly advantageous compositions, ie compositions with low magnetostriction.

As evidenced by the examples given in Table 7, particularly advantageous quantitative magnetostriction values below 5 ppm are more than 13 at% Si and the heat treatment temperature is less than 50 ° C. below the upper limit (T _a2 ) of the optimum annealing range. Can be realized. A much smaller quantitative saturation magnetostriction of less than 2 ppm can be realized when the Si content is greater than 14 at% and less than 18 at% and the heat treatment temperature is lower than 50 ° C. below the upper limit T _a2 of the optimum annealing range. A much lower quantitative saturation magnetostriction of less than 1 ppm can be realized if the Si content is greater than 15 at% and the heat treatment temperature is below 50 ° C. below the upper limit T _a2 of the optimum annealing range.

The higher the permeability, the more important the small quantitative magnetostriction. For example, alloys with permeability values greater than 500 or greater than 1000 have a significantly lower correlation to mechanical stress when the quantitative saturation magnetostriction is less than 2 ppm or less than 1 ppm.

The alloy may have a quantitative saturation magnetostriction of less than 5 ppm. If the permeability is less than 500, alloys with saturation magnetostriction lower than this lower limit continue to have good soft magnetic properties even in the presence of internal stresses.

MPa에서

ppm,

MPa에서

및

MPa에서

ppm와 같은, 610℃에서 4초 동안 열처리 후 어닐링 응력에 따른 포화 자왜값이 합금 Fe_{75 .5}Cu₁Nb_{1 .5}Si_{15 .5}B_6.5에 대해 측정된다.

이라는 점에서 이는 약간의 자왜 감소에 대응한다. 다른 합금 조성물은 비슷한 거동을 보인다.The saturation magnetostriction may still vary to some extent depending on the tensile stress σ _a applied during the heat treatment. for example

In MPa

ppm,

In MPa

And

In MPa

such as ppm, and then heat-treated at 610 ℃ for 4 seconds, the saturation magnetization waegap according to the annealing stress is measured for the alloy _{Fe 75 .5 Cu 1 Nb 1 .5} Si 15 .5 B 6.5.

In this respect it corresponds to a slight magnetostriction reduction. Other alloy compositions show similar behavior.

FIG. 13 shows a schematic view of an apparatus 1 suitable for producing an alloy having a composition according to one of the above embodiments in the form of a tape. The apparatus 1 comprises a continuous furnace 2 with a temperature zone 3, which is set such that the oven temperature of the temperature zone is within 5 ° C. of the annealing temperature T _a . The device 1 also comprises a coil 4 on which the amorphous alloy 5 is wound and a winding coil 6 on which the heat treated tape 7 is wound. The tape is transferred from the coil 4 to the receiving coil 6 via the continuous line 2 at a predetermined speed s. In this method the tape 7 is subjected to a tensile stress σ _a which is applied in the direction of movement from the device 9 to the device 10.

The apparatus 1 also includes an apparatus 8 for continuously measuring the magnetic properties of the tape 6 after the tape has been heat treated and removed in the continuous furnace 2. The tape 7 is no longer subjected to tensile stress in the region of the device 8. The measured magnetic properties can be used to control the tensile stress σ _a received when the tape 7 passes through the furnace 2 continuously. This is shown schematically in FIG. 13 by arrows 9, 10. The measurement of the magnetic properties and the continuous adjustment of the tensile stress can improve the normality of the magnetic properties along the length of the tape.

Claims (24)

Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z and impurities up to 1 at%,
M is at least one of the elements Mo, Ta, or Zr, T is at least one of the elements V, Mn, Cr, Co, or Ni, Z is at least one of the elements C, P, or Ge, 0 at% ≦ a <1.5 at%, 0 at% ≤b <2 at%, 0 at% ≤ (b + c) <2 at%, 0 at% ≤d <5 at%, 10 at% <x <18 at%, 5 at% <y <11 at% and 0 at% ≤z <2 at%
Consists of tapes,
At least 50 vol% of the particles have a nanocrystalline structure with an average particle size of less than 100 nm, a hysteresis loop with a central linear portion, a residual magnetic ratio of less than 0.1 (J _r / J _s ), and an antimagnetic field of less than 10% Alloy having a ratio of strength (H _c ) to anisotropic magnetic field strength (H _a ). The alloy of claim 1, wherein the residual magnetic ratio (J _r / J _s ) is less than 0.05. 3. The alloy of claim 1 or 2, wherein the ratio of the magnetic field strength to the anisotropic magnetic field strength is less than 5%. The alloy of claim 1, further having a permeability μ between 40 and 3000. 5. The alloy according to any one of claims 1 to 4, further having a saturation magnetostriction of less than 2 ppm, preferably less than 1 ppm. 6. The alloy of claim 1 having a magnetic permeability of less than 500 and a saturation magnetostriction of less than 5 ppm. 7. The alloy of claim 1, wherein b <0.5. The alloy of any one of claims 1 to 7, wherein a <0.5. The alloy of claim 1, wherein 14 at% <x <17 at% and 5.5 at% <y <8 at%. The alloy of claim 1, wherein the tape has a thickness of 10 μm to 50 μm. The alloy of any one of the preceding claims, wherein at least 70% of the particles have an average particle size of less than 50 nm. The alloy according to claim 1, wherein the crystalline particles have an elongation of at least 0.02% in a preferred direction. Magnetic core made of the alloy according to any one of claims 1 to 12. The magnetic core according to claim 13, which has the form of a wound tape. 15. The magnetic core according to claim 13 or 14, wherein the tape is coated with an insulating layer. A DC-tolerant current transformer comprising a magnetic core according to any one of claims 13 to 15 having a permeability between 1500 and 3000. A transformer comprising the magnetic core according to any one of claims 13 to 15 having a permeability between 200 and 1500. Storage choke comprising the magnetic core according to claim 13 having permeability between 50 and 200. Fe _{100 -abcdxy- z} Cu _a Nb _b M _c T _d Si _x B _y Z _z and 1 at% or less of impurities, M is one or more of the elements Mo, Ta or Zr, and T is the element V, Mn At least one of Cr, Co, or Ni, and Z is at least one of the elements C, P, or Ge, 0 at% ≦ a <1.5 at%, 0 at% ≦ b <2 at%, 0 at% ≦ (b + c) Amorphous alloys with <2 at%, 0 at% ≤d <5 at%, 10 at% <x <18 at%, 5 at% <y <11 at% and 0 at% ≤z <2 at% Preparing a tape manufactured by
Heat-treating the tape while applying a tensile stress in a continuous furnace at _a predetermined temperature (T _a ) of 450 ° C. ≦ T _a ≦ 750 ° C. 20. The method of claim 19, wherein the tape passes through the continuous furnace at a predetermined speed s such that the time period the tape spends in the continuous zone temperature range of _a predetermined temperature Ta is between 2 seconds and 2 minutes. Tape manufacturing method. 21. The method of claim 19 or 20, wherein the tape passes through the continuous furnace under a tensile stress of 5 MPa to 800 MPa. 22. The method according to any of claims 19 to 21, wherein the tensile stress σ _a is a ratio.

Tape is selected according to the composition, where μ is the desired permeability and μ _Test is the permeability realized at the test stress (σ _Test ). 23. The method according to any of claims 19 to 22, wherein the temperature (T _a ) is selected according to the niobium content (b) according to the ratio (T _x1 +50 ° C) ≤T _a ≤ (T _x2 +30 ° C). Tape manufacturing method. 24. A desired magnetic permeability or anisotropic magnetic field value, a maximum residual magnetic ratio (J _r / J _s ) of less than 0.1, a maximum magnetic field strength to anisotropic magnetic field strength of less than 10%. The ratio of H _c / H _a and the allowable deviation range for each of these values are predetermined,
As the tape leaves the furnace, the magnetic properties of the tape continue to be measured,
And when the deviation from the allowable magnetic characteristic deviation range is observed, the tensile stress of the tape is adjusted so that the measured magnetic characteristic value returns to within the allowable deviation range.

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