JP2005256104A - Fe-BASED AMORPHOUS ALLOY RIBBON HAVING SMALL OWN MAGNETOSTRICTION, AND IRON CORE MANUFACTURED WITH THE USE OF IT - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an Fe-based amorphous alloy ribbon which has own magnetostriction reduced to a low level of 6×10<SP>-6</SP>or lower by controlling the exciting power VA and magnetic flux density B1 of the ribbon to predetermined ranges, and as a result, reduces the noise of an electric power transformer, a high frequency transformer, a choke coil and an electric reactor. <P>SOLUTION: The Fe-based amorphous alloy ribbon having small own magnetostriction has the exciting power VA of 1.5 W/kg or less, and the magnetic flux density B1 of 1.3 T or higher when the magnetic field of 80 A/m is applied. The above Fe-based amorphous alloy ribbon having small own magnetostriction comprises, by atom%, 1% to 19% Si, 5% to 19% B, 0.02% to 4% C, 0.01% to 12% P and the balance Fe with unavoidable impurities. A stacked iron core having the small own magnetostriction by an alternating electric current is manufactured by winding the ribbon into a toroidal shape, or by stamping it into a predetermined shape and layering stamped ribbons. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an amorphous alloy ribbon used for iron cores such as a power transformer, a high-frequency transformer, a choke coil, and a reactor.

Centrifugal quenching methods, single roll methods, twin roll methods, and the like are known as methods for continuously producing ribbons and wires by rapidly cooling an alloy from a molten state.
In these methods, molten metal is ejected from an orifice or the like on the inner peripheral surface or outer peripheral surface of a metal drum that rotates at high speed, whereby the molten metal is rapidly solidified to produce a ribbon or wire.
Furthermore, by selecting an alloy composition appropriately, an amorphous alloy similar to a liquid metal can be obtained, and a material excellent in magnetic properties or mechanical properties can be produced.
This amorphous alloy is considered promising as an industrial material in many applications due to its excellent characteristics. Among them, as an application of iron core materials such as a power transformer and a high-frequency transformer, an Fe-based amorphous alloy ribbon, for example, Fe--, for example, has a low iron loss and a high saturation magnetic flux density and magnetic permeability. Si-B system is adopted.

However, the transformer using the Fe-Si-B amorphous alloy ribbon as the core material can lower the iron loss compared to the transformer using the silicon steel plate as the core material, so the energy loss can be reduced. It has been pointed out that will grow.
In spite of such indications, a technique relating to noise reduction of a transformer or a choke coil using an amorphous alloy ribbon as a core material is disclosed in, for example, the choke coil core described in Patent Document 1. In order to reduce noise due to magnetic flux leaking from the gap, there is almost no method to reduce noise by making gapless using a ribbon with a crystal layer in the ribbon, and there is almost no current situation is there.

Regarding the excitation power of the Fe—Si—B amorphous alloy ribbon, a ribbon having an iron loss not exceeding about 0.3 W / Kg and an excitation power not exceeding about 1 VA / Kg is disclosed ( Patent Document 2).
In addition, by defining the alloy composition within a specific range, an iron loss of about 0.35 W / Kg or less and an excitation power of about 1 VA / Kg or less in which saturation magnetization, Curie temperature, and crystallization temperature are practically balanced. The excellent thin ribbon which has is disclosed (patent document 3).
In Patent Document 4, the excitation power is about 0.4 to 0.5 W / Kg by setting the plate thickness variation to 10% or less, and the magnetic flux density when a magnetic field of 800 A / m is applied is 1.5. A ribbon having a characteristic of about ~ 1.6T is disclosed.
Noise greatly depends on the magnetostriction of the ribbon, but Patent Document 2, Patent Document 3 and Patent Document 4 have no description regarding noise or magnetostriction.
Patent Document 4 describes excitation power and magnetic flux density. The magnetic flux density described is the magnetic flux density when a magnetic field of 800 A / m is applied, and in the case of an amorphous alloy ribbon. Is approximately equal to the saturation magnetic flux density.
JP-A-4-320014 Japanese National Patent Publication No. 5-503962 JP-T 8-505188 JP-A-7-113151

As described above, it is obvious that there is no technique for reducing the noise of the transformer using the Fe-based amorphous alloy ribbon as the core.
Therefore, the present invention reduces the magnetostriction of the ribbon to a low level of 6 × 10 ⁻⁶ or less by controlling the ribbon excitation power VA and the magnetic flux density B1 within a predetermined range. As a result, the power transformer An object of the present invention is to provide a Fe-based amorphous alloy ribbon that enables noise reduction of a high-frequency transformer, a choke coil, and a reactor.

In order to reduce the noise of the transformer using the Fe-based amorphous alloy ribbon, the present invention measures the magnetostriction of the ribbon, which is considered to be the main factor of the noise, and further obtains the obtained data. It was discovered as a result of detailed analysis.
The gist of the present invention is as follows.

(1) The excitation power VA measured at a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T is 1.5 W / Kg or less, and the magnetic flux density B1 when a magnetic field of 50 Hz and 80 A / m is applied is 1. A Fe-based amorphous alloy ribbon having a small operating magnetostriction, characterized by being 3T or more.

(2) Si of 1% to 19% in atomic%, B of more than 19% to 19% or less, C of 0.02% to 4%, P of 0.01% to 12%, the balance being Fe and 2. The Fe-based amorphous alloy ribbon having a small operating magnetostriction according to claim 1, wherein the ribbon is made of inevitable impurities.

(3) A wound iron core having a small operating magnetostriction in alternating current, wherein the Fe-based amorphous alloy ribbon described in (1) or (2) is wound around a toroid.

(4) An iron core having a small operating magnetostriction in alternating current, wherein the Fe-based amorphous alloy ribbon according to (1) or (2) is punched into a predetermined shape and laminated.

According to the present invention, the maximum magnetic flux density of 1.3 T is controlled by controlling the magnetic flux density B1 when the excitation power VA is 1.5 W / Kg or less and a magnetic field of 80 A / m 2 is applied to a range of 1.3 T or more. A Fe-based amorphous alloy ribbon having a small operating magnetostriction with a magnetostriction of 6 × 10 ⁻⁶ or less when alternating-current excitation is performed in the above can be obtained.
Furthermore, by controlling the excitation power VA to 1.0 W / Kg or less and the magnetic flux density B1 to 1.4 T or more, the magnetostriction when AC excitation is performed at the maximum magnetic flux density of 1.3 T is 5 × 10 ⁻⁶ or less. It is possible to obtain a Fe-based amorphous alloy ribbon having a small operating magnetostriction.
Furthermore, by controlling the excitation power VA to 0.5 W / Kg or less and the magnetic flux density B1 to 1.5 T or more, the magnetostriction when AC excitation is performed at the maximum magnetic flux density of 1.3 T is 3 × 10 ⁻⁶ or less. It is possible to obtain a Fe-based amorphous alloy ribbon having a small operating magnetostriction.
When these Fe-based amorphous alloy ribbons with reduced operating magnetostriction are used as iron cores for power transformers, high-frequency transformers, choke coils, reactors, etc., the magnetostriction vibration of the ribbons, which is the main cause of noise, is reduced. Therefore, not only the noise itself when assembled in a transformer or the like is reduced, but also the parts used as noise countermeasures can be reduced, so that the transformer and the like can be reduced in size and cost.

A feature of the present invention is that when an Fe-based amorphous alloy ribbon is excited at a predetermined AC frequency and a predetermined operating magnetic flux density, the excitation power VA at that time and a magnetic field of 80 A / m are applied. By controlling the magnetic flux density B1 within a specific range, the magnetostriction (operating magnetostriction) generated in the ribbon itself can be reduced.
The operating magnetostriction here refers to the amount of strain (maximum amplitude value of strain) generated in a predetermined direction in the plane of the ribbon when a magnetic field having a predetermined magnetic flux density is applied to the ribbon at a predetermined AC frequency. That is. It is preferably defined by the maximum amplitude value of strain in the longitudinal direction of the ribbon.

Even if the excitation power VA or the magnetic flux density B1 is individually within the range of the present invention, the low magnetostriction of the present invention cannot be obtained. A low magnetostriction is obtained only when the excitation power VA and the magnetic flux density B1 are simultaneously within the scope of the present invention.
The excitation power VA and the magnetic flux density B1 can be controlled by the composition of the ribbon and the annealing conditions of the ribbon.
The excitation power VA is a power required when exciting up to a predetermined magnetic flux density, and is a parameter of a completely different dimension because it differs from the magnetic flux density B1 in terms of both units. The inventor has succeeded in obtaining a ribbon having a controlled operating magnetostriction by combining these parameters of different dimensions.

By controlling the excitation power VA to 1.5 W / Kg or less and the magnetic flux density B1 to 1.3 T or more, the operating magnetostriction can be set to a low value of 6 × 10 ⁻⁶ or less.
Further, by controlling the excitation power VA to 1.0 W / Kg or less and the magnetic flux density B1 to 1.4 T or more, the operating magnetostriction can be set to a lower value of 5 × 10 ⁻⁶ or less.
When used in a more severe environment, lower operating magnetostriction of 3 × 10 ⁻⁶ or less is obtained by controlling the excitation power VA to 0.5 W / Kg or less and the magnetic flux density B1 to 1.5 T or more. It becomes possible.
That is, preferably in order to obtain the operation magnetostrictive 5 × ^{10 -6} or less exciting power VA to 1.0 W / Kg or less, it is desirable that the magnetic flux density B1 above 1.4 T, further, 3 × 10 ^{- In} order to obtain a lower operating magnetostriction of ⁶ or less, it is preferable that the excitation power VA is 0.5 W / Kg or less and the magnetic flux density B1 is 1.5 T or more.
Here, the prescribed excitation power VA is the excitation power measured at a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T, and the magnetic flux density B1 is the maximum magnetic flux density when excited at a frequency of 50 Hz and a maximum magnetic field of 80 A / m. . However, although the magnetic flux density B1 is completely different from the saturation magnetic flux density, it does not become larger than the saturation magnetic flux density.

The low magnetostrictive ribbon according to the present invention can be composed of elements composed of main elements of Fe, Si, B, C, and P and inevitable impurities.
Fe is preferably in the range of 78 atomic% to 86 atomic%. This is because when Fe is less than 78 atomic%, a sufficient magnetic flux density cannot be obtained, and when it exceeds 86 atomic%, amorphous formation becomes difficult and good magnetic properties cannot be obtained. . More preferably, when Fe is made more than 80 atomic% and 82 atomic% or less, stable amorphization can be achieved while maintaining a sufficient magnetic flux density.

  Si is preferably in the range of 1 atomic% to 19 atomic%. This is because when Si is less than 1 atomic%, amorphous is hardly formed stably, and when Si exceeds 19 atomic%, the magnetic flux density decreases. A Si content of 2 atomic% or more and less than 5 atomic% is more preferable because amorphization is stable and a decrease in magnetic flux density is suppressed.

B is preferably in the range of more than 5 atomic% and 19 atomic% or less. If B is 5 atomic% or less, it is difficult to stably form amorphous, and even if it exceeds 19 atomic%, further improvement in the ability to form amorphous is not recognized, and the magnetic flux density also decreases.
B of more than 5 atomic% and 16 atomic% or less is more preferable because the amorphization is stable and the decrease in magnetic flux density is suppressed. By setting the content of B in the range of 14 atomic% to 16 atomic%, the amorphous can be further stabilized.

C is an element having an effect on the castability of the ribbon. By containing C, the wettability between the molten metal and the cooling substrate is improved, and a good ribbon can be formed.
If C is less than 0.02 atomic%, this effect cannot be obtained. Further, even if C is contained more than 4 atomic%, no further improvement of this effect is recognized. Therefore, the range of 0.02 atomic% or more and 4 atomic% or less is preferable.

The present inventor has already found that in Patent Document 5, 0.008 mass% or more and 0.1 mass% (0.16 atomic%) or less of P increases the allowable content of Mn and S and is inexpensive iron. It has been found that it has the effect of enabling the use of sources.
Further, in Patent Document 6, it has been found that P of 0.2 atomic% or more and 12 atomic% or less has an effect of reducing variation in magnetic flux density.
In the present invention, the effect of P can be obtained by containing P in the range of 0.01 atomic% or more and 12 atomic% or less.
Furthermore, the inclusion of a predetermined range of P has an effect of facilitating the control of the excitation power VA and the magnetic flux density B1.
More preferably, the range of P is 0.05 atomic% or more and 12 atomic% or less. In order to make the effect of P more prominent, it may be in the range of about 1 atomic% to 6 atomic%.
JP-A-9-202946 JP 2002-220646 A

  By using such an Fe-based amorphous alloy ribbon of the present invention as a material for an iron core such as a power transformer, a high-frequency transformer, a choke coil, or a reactor, noise can be reduced.

The ribbon of the present invention melts a predetermined alloy component and ejects the molten metal through a slot nozzle onto a moving cooling substrate to rapidly solidify the alloy, for example, by a single roll method or a twin roll method. Can be manufactured.
Single roll equipment includes centrifugal quenching equipment that uses the inner wall of the drum, equipment that uses an endless type belt, and an auxiliary roll that is an improved version of these equipment, under reduced pressure or in vacuum, or in an inert gas A casting device is also included.

In the present invention, the thickness, width, etc. of the ribbon are not particularly specified, but the ribbon thickness is preferably 10 μm or more and 100 μm or less, for example. The plate width is preferably 20 mm or more.
As a raw material of the present invention, for example, some steel types produced in an iron making process using iron ore as a raw material can be used as an iron source.
Examples of the alloy composition include Fe ₇₉ Si ₃ B ₁₅ C ₁ P ₂ , Fe ₈₁ Si _2.5 B ₁₅ C ₁ P _0.5 , Fe ₈₂ Si _2.2 B ₁₅ C _0.5 P _0.3 , Fe ₈₄ Si _2.7 B ₁₀ C _0.3 P ₃ , Fe _84.8 Si _2.5 B ₇ C _0.7 P ₅ , Fe ₈₁ Si ₃ B ₁₅ C _0.96 P _{0.04, and the} like.

The excitation power VA and the magnetic flux density B1 can be controlled by the composition of the ribbon or the magnitude of the magnetic field, the heat treatment temperature, and the time in the heat treatment in the magnetic field of the ribbon.
The ribbon composition is in the above range, the magnetic field strength in the heat treatment in the magnetic field is in the range of 100 A / m to 10000 A / m, the heat treatment temperature is in the range of 250 ° C. to the crystallization temperature, and the time is in the range of 0.1 to 20 hours. Can be controlled.
When it is desired to lower the excitation power VA, the heat treatment temperature may be increased and the time may be set longer. In order to increase the magnetic flux density B1, the Fe content may be increased, the magnetic field strength may be increased, or the heat treatment temperature may be increased.

  An iron core having a small operating magnetostriction in alternating current is obtained by subjecting the above-described inventive ribbon to a toroidal wound core, or by punching the inventive ribbon into a predetermined shape and subjecting the laminated core to the heat treatment in the magnetic field described above. be able to.

By the way, in a power transformer, a high frequency transformer, a choke coil, and a reactor, it is preferable that not only magnetostriction but also iron loss is low. In particular, in the high frequency region, heat generation may be a problem when the iron loss is large.
It is preferable if the iron loss by single plate measurement at a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T is 0.15 W / Kg or less. More preferably, if the iron loss is 0.12 W / Kg, a transformer having excellent energy loss can be manufactured.

Hereinafter, the present invention will be described in detail based on examples.
A _master alloy having a composition containing Fe _bal Si _2.6 B ₁₅ C ₁ P _{0.1 in} atomic percent and impurities of 0.2 atomic percent such as Mn and S was manufactured.
The mother alloy was melted at high frequency in a quartz crucible, and the molten metal was jetted onto a Cu alloy cooling roll through a rectangular slot nozzle having an opening shape of 0.4 mm × 25 mm attached to the tip of the crucible. The diameter of the cooling roll is 580 mm, and the rotation speed is 800 rpm. By this casting, an amorphous ribbon having a thickness of about 27 μm and a width of 25 mm was obtained.
In order to control the excitation power VA of the ribbon and the magnetic flux density B1 to various values, the ribbon was cut into a length of 120 mm and annealed in a magnetic field.
That is, in the example of the present invention, the annealing temperature was 300 to 380 ° C., the time was 0.5 to 3 hours, and the magnetic field strength was 400 to 4000 A / m.
On the other hand, in the comparative example, at least one condition in which the annealing temperature is less than 250 ° C., the time is 0.1 hour or less, or the strength of the magnetic field is less than 100 A / m is selected, and the other conditions are the same as those in the present invention example. The magnetic field direction was the longitudinal direction of the ribbon.
Excitation power VA and magnetic flux density B1 were controlled by these temperature, time, and magnetic field strength.
The sample after annealing in a magnetic field was excited using a SST (single plate magnetometer) at an excitation power of VA when excited at a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T, and at a frequency of 50 Hz and a maximum magnetic field of 80 A / m. The iron loss was measured under the same measurement conditions as the maximum magnetic flux density B1 and the excitation power VA.
The operating magnetostriction λp-p is fixed at one side of a 120 mm long ribbon, with a reflector on the opposite side, and with a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T. Measurements were made using the Doppler method.
The results are shown in Table 1.

The excitation power VA is 1.5 W / Kg or less and the magnetic flux density B1 is 1.3T or more in the scope of the present invention. 1-No. 18, the values of the operating magnetostriction λp-p are all low values of 6 × 10 ⁻⁶ or less.
In particular, no. 1-No. When the excitation power VA 13 is 1.0 W / Kg or less and the magnetic flux density B1 is 1.4 T or more, λp-p is further reduced to 5 × 10 ⁻⁶ or less.
No. 1-No. When the excitation power VA of No. 7 is 0.5 W / Kg or less and the magnetic flux density B1 is 1.5 T or more and the excitation power VA is further reduced and the magnetic flux density B1 is increased, λp-p is further lowered to 3 × 10 ⁻⁶ or less. It turns out that it becomes a value.
The iron loss is no. 1-No. In all 18, it was as low as 1.50 W / Kg or less.

Comparative Example No. 19, no. The excitation power VA of 20 is 1.5 W / Kg or less, which is within the scope of the present invention, but the magnetic flux density B1 is lower than 1.3 T and outside the scope of the present invention.
No. 21, no. Although the magnetic flux density B1 of 22 is within the range of the present invention as 1.3T or more, the excitation power VA is larger than 1.5 W / Kg and is outside the range of the present invention.
Thus, no. 19-No. 22, one of the excitation power VA and the magnetic flux density B1 is outside the range of the present invention, and in such a case, λp-p becomes a large value of 6 × 10 ⁻⁶ or more.
No. 23-No. 29, both the excitation power VA and the magnetic flux density B1 are outside the scope of the present invention, and in this case, λp-p is a large value of 6 × 10 ⁻⁶ or more.

A _master alloy having a composition containing Fe _bal Si _2.7 B _10.2 C _0.9 P _{5.3 at} atomic percent and impurities such as 0.2 atomic percent of Mn, S and the like was manufactured. Cast into amorphous ribbon by the method. The obtained ribbon had a thickness of 26 μm and a width of 25 mm.
In the same manner as in Example 1, heat treatment was performed under various annealing conditions in a magnetic field to obtain a ribbon with controlled excitation power VA and magnetic flux density B1, and excitation power VA, magnetic flux density B1, λp− p, Iron loss was evaluated.
The results are shown in Table 2.

Excitation power VA is 1.5 W / Kg or less, and magnetic flux density B1 is 1.3T or more of the present invention range No. 30-No. In 45, the values of the operating magnetostriction λp-p are all low values of 6 × 10 ⁻⁶ or less.
In particular, no. 30-No. When the excitation power VA of 36 is 1.0 W / Kg or less and the magnetic flux density B1 is 1.4 T or more, λp-p is further reduced to 5 × 10 ⁻⁶ or less.
No. As shown in FIG. 30, when the excitation power VA is 0.5 W / Kg or less and the magnetic flux density B1 is 1.5 T or more and the excitation power VA further decreases and the magnetic flux density B1 increases, λp-p is 3 × 10 ⁻⁶ or less. It can be seen that the value is even lower.
The iron loss is no. 30-No. In all 45, it was a low thing of 1.50 W / Kg or less.
Comparative Example No. 46-No. The excitation power VA of 48 is 1.5 W / Kg or less, which is within the scope of the present invention, but the magnetic flux density B1 is lower than 1.3 T and outside the scope of the present invention.
No. 49-No. The magnetic flux density B1 of 51 is within the range of the present invention as 1.3T or more, but the excitation power VA is larger than 1.5 W / Kg and is outside the range of the present invention.
Thus, no. 46-No. 51, one of the excitation power VA and the magnetic flux density B1 is outside the scope of the present invention, and it can be seen that λp-p in such a case is a large value of 6 × 10 ⁻⁶ or more.

A _master alloy having a composition containing Fe _bal Si _2.4 B ₁₃ C _0.8 P _0.9 and 0.2 atomic% of impurities such as Mn and S in atomic% is manufactured. Cast into an amorphous ribbon. The obtained ribbon had a thickness of 27 μm and a width of 25 mm.
In the same manner as in Example 1, heat treatment was performed under various annealing conditions in a magnetic field to obtain a ribbon with controlled excitation power VA and magnetic flux density B1, and excitation power VA, magnetic flux density B1, λp− p, Iron loss was evaluated.
The results are shown in Table 3.

In No. 52 to No. 57 in which the excitation power VA is 1.5 W / Kg or less and the magnetic flux density B1 is 1.3 T or more, the values of the operating magnetostriction λp-p are all 6 × 10 ⁻⁶ or less. Is a low value.
In particular, no. 52-No. It can be seen that when the excitation power VA of 54 is 1.0 W / Kg or less and the magnetic flux density B1 is 1.4 T or more, λp-p further decreases to 5 × 10 ⁻⁶ or less.
The iron loss is no. 52-No. In all 57, it was as low as 1.50 W / Kg or less.
Comparative Example No. 58, no. 59, the magnetic flux density B1 is 1.3 T or more and falls within the scope of the present invention, but the excitation power VA is larger than 1.5 W / Kg and is outside the scope of the present invention. Thus, no. 58, no. 59, one of the excitation power VA and the magnetic flux density B1 is outside the scope of the present invention, and it can be seen that λp-p in such a case is a large value of 6 × 10 ⁻⁶ or more.

The ribbons of sample 5 (invention example) and sample 28 (comparative example) of Example 1 were each cut to a length of 3 m and wound on a quartz bobbin having an outer diameter of 60 mm to produce a toroidal iron core.
After winding an exciting coil around the iron core, annealing was performed in a magnetic field at a temperature of 360 ° C. and a holding time of 2.5 hours with a magnetic field of 4000 A / m applied in the circumferential direction of the iron core.
After annealing, a strain gauge was attached to the outermost periphery of the iron core, and the operating magnetostriction of the iron core was measured under the conditions of a frequency of 50 Hz and a maximum magnetic flux density of 1.3T. As a result, the operating magnetostriction of the iron core of the present invention example is 3.85 × 10 ⁻⁶ , and the iron core of the comparative example is 9.62 × 10 ⁻⁶ , and the operating magnetostriction is reduced by using the ribbon of the present invention example. A small wound core can be manufactured.

Similarly, the ribbons of Sample 5 (Example of the present invention) and Sample 28 (Comparative Example) of Example 1 were cut and then laminated to produce a rectangular core having a long side of 100 mm and a short side of 50 mm. .
After winding an exciting coil around the iron core, annealing was performed in a magnetic field at a temperature of 360 ° C. and a holding time of 2.5 hours with a magnetic field of 4000 A / m applied in the circumferential direction of the core.
After annealing, a strain gauge was attached to the upper end surface of the iron core, and the operating magnetostriction of the iron core was measured under the conditions of a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T. As a result, the operating magnetostriction of the iron core of the present invention example is 2.92 × 10 ⁻⁶ , and the iron core of the comparative example is 8.89 × 10 ⁻⁶ , and the operating magnetostriction is reduced by using the ribbon of the present invention example. A small wound core can be manufactured.

  When these Fe-based amorphous alloy ribbons with reduced operating magnetostriction are used as iron cores for power transformers, high-frequency transformers, choke coils, reactors, etc., the magnetostriction vibration of the ribbons, which is the main cause of noise, is reduced. For this reason, not only the noise itself when assembled in a transformer or the like is reduced, but also the parts used as noise countermeasures can be reduced, so that the transformer and the like can be reduced in size and cost.

Claims (4)

  The excitation power VA measured at a frequency of 50 Hz and a maximum magnetic flux density of 1.3 T is 1.5 W / Kg or less, and the magnetic flux density B1 when a magnetic field of 50 Hz and 80 A / m is applied is 1.3 T or more. A Fe-based amorphous alloy ribbon having a small operating magnetostriction, characterized in that:   At least 1% to 19% Si, 5% to 19% B, 0.02% to 4% C, 0.01% to 12% P, the balance being Fe and inevitable impurities The Fe-based amorphous alloy ribbon having a small operating magnetostriction according to claim 1, characterized by comprising:   A wound iron core with a small operating magnetostriction in alternating current, wherein the Fe-based amorphous alloy ribbon according to claim 1 or 2 is wound around a toroid.   An iron core having a small operating magnetostriction in alternating current, wherein the Fe-based amorphous alloy ribbon according to claim 1 or 2 is punched into a predetermined shape and laminated.