JPH08238543A - Ultra-thin amorphous alloy with high permeability and low iron loss - Google Patents

Abstract

(57) [Abstract] [Problem] In a good condition without pinholes, the plate thickness is 10
Ultra-thin amorphous alloys of less than μm are required. SOLUTION: General formula: (Fe _1-x M _x ) _100-z Y _z (In the formula, M is one selected from Cr, Mo, W, Cr + Mo, Cr + W, Cr + Mo + W. , Y is at least one selected from Si, B, P and C, and x and z are 0.01 ≦ x ≦ 0.1 and 15 ≦ z ≦ 30), and the plate thickness is 10 μm. Is less than
It is an ultrathin amorphous alloy with high magnetic permeability and low iron loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires high permeability and low iron loss at high frequencies such as transformers, noise filters, saturable reactors, microminiature inductance elements for reducing spike noise, zero-phase current transformers, and magnetic heads. Ultra-thin amorphous alloy suitable for the intended use.

[0002]

2. Description of the Related Art As electronic devices have become more sophisticated, magnetic components used as important functional parts are also required to have higher performance. Therefore, excellent magnetic properties are required for the magnetic materials used for these magnetic parts, and particularly for many magnetic parts such as current sensors such as zero-phase current transformers and noise filters, the magnetic permeability is high. The material is effective.
First, the noise filter will be described. A switching power supply is widely used as a stabilized power supply for peripheral devices of electronic computers and general communication devices. In a switching power supply, when a power supply voltage is input to a device from a power supply line, a noise voltage other than a predetermined power supply voltage may enter the device and be input. Further, high frequency noise having a switching frequency as a basic frequency or load, for example, noise in the MHz range generated from a logic circuit of a personal computer becomes a problem.

In order to reduce these conduction noises, for example, a common mode choke coil as shown in FIG. 1 is used as a noise filter. In FIG. 1, a choke coil 1 is a magnetic core 2 provided with a pair of windings 3a and 3b so as to cancel out magnetic flux due to a reciprocating current, and capacitors 4a, 4b and 4c are connected between the windings 3a and 3b. The connection points of the capacitors 4b and 4c are grounded.
When this filter is inserted in the power supply line, the magnitude of the noise output voltage with respect to the noise input voltage is related to the magnetic permeability of the magnetic core, and the larger the magnetic permeability, the smaller the noise output voltage. Further, it is necessary to effectively function not only in the low frequency region but also in the high frequency region of 1 MHz or higher, and for this reason, it is necessary that the frequency characteristic of magnetic permeability is also good.

Conventionally, ferrite has been used as a material for forming the magnetic core of the common mode choke coil. However, recently, relatively low frequency range (10-450kHz)
In contrast to stricter noise regulations, ferrite has a drawback that it cannot sufficiently reduce noise because of its low magnetic permeability in the low frequency range. Therefore, there has been a demand for a magnetic core having a large magnetic permeability particularly in a low frequency range and excellent frequency characteristics.

In recent years, switching power supplies incorporating a magnetic amplifier have been widely used. The main part of this magnetic amplifier is a saturable reactor, and a magnetic core material having excellent rectangular magnetization characteristics is required. Conventionally, as such a magnetic core material, Senda (trade name) made of Fe-Ni crystalline alloy has been used.

However, although the senda-delta is excellent in the rectangular magnetizing property, it has a large coercive force at a high frequency of 20 kHz or more, and an eddy current loss increases to generate heat, which makes it unusable. For this reason, the switching frequency of the switching power supply incorporating the magnetic amplifier was limited to 20 kHz or less.

On the other hand, in recent years, there has been a demand for a higher switching frequency in combination with a demand for smaller and lighter switching power supplies. At present, however, amorphous alloys are practically used. The maximum frequency is limited to 200-500kHz, and there is a demand for materials that support higher frequencies. Also, D built into the power supply
For magnetic parts used in C-DC converters,
Similarly, low loss is an important issue.

On the other hand, it is generally known that a metal material can suppress eddy current loss and improve high frequency characteristics by reducing the plate thickness. Among metal materials, an amorphous alloy having good high-frequency characteristics is usually produced by a liquid quenching method, and the single roll method (FIG. 2) is usually used as the means. If there is no width to some extent, there is a problem in practical use.Under the conventional conditions, the strip thickness of 2 mm or more is a limit of about 11 to 12 μm, and such strips have relatively many pinholes. However, there was a problem in practicality including high frequency.

[0009]

As described above, high magnetic permeability and low iron loss are required up to high frequencies (up to MHz range) for various magnetic cores. These are highly efficient equipment, compact and lightweight, and compact magnetic core. , Leading to higher performance.

It is an object of the present invention to provide an ultrathin amorphous alloy having a plate thickness of 10 μm or less in a good state without pinholes or the like so as to satisfy the above magnetic characteristics.

[0011]

The ultrathin amorphous alloy of the present invention has a general formula: (Fe _1-x M _x ) _100-z Y _z (wherein M is Cr, Mo, W, Cr + Mo, One of Cr + W and Cr + Mo + W is selected, Y is one or more selected from Si, B, P, and C, and x and z are 0.01 ≦ x ≦ 0.1, 15 ≦ z ≦ 30.
Is an alloy represented by the formula (1), and is an ultrathin amorphous alloy with high magnetic permeability and low iron loss, which is characterized by having a plate thickness of 10 μm or less.

The reasons for limiting the composition of the alloy of the present invention will be described below. M is an element that lowers the viscosity when the alloy melts, improves the wettability with the roll, and is effective for improving the surface properties of the alloy.However, if it is too small, the effect cannot be obtained, and if too large, the Curie temperature increases. Lower M, thus defining M x
The range is 0.01 to 0.1. It is preferably 0.015 to 0.07, and more preferably 0.02 to 0.055. Especially M
Cr alone, a combination of Cr + Mo, Cr + W is preferable, and further Fe
It is possible to replace up to 50 atomic% with Ni.

Y is an element necessary for amorphization, but if it is less than 15 atom% or exceeds 30 atom%, it becomes difficult to amorphize, so the amount is made to be 15 to 30 atom%. It is preferably 17 to 27 atomic%, and more preferably
It is 17 to 25 atom%. Especially when the amount of Si and C is less than 5 atom% or exceeds 20 atom%, or the amount of B and P is 10 atom%.
If less than 20% or more than 20 atomic%, the surface property of the obtained alloy deteriorates and it is not preferable for ultrathinning of 10 μm or less. , P) ≦
25 atom% is preferred. More preferably, 7 ≦ (Si, C) ≦ 15 atomic%, and 10 ≦ (B, P) ≦ 20 atomic%.

The ultrathin amorphous alloy of the present invention is manufactured by the following manufacturing method. That is, when producing an amorphous alloy ribbon by jetting the molten alloy having the alloy composition of the present invention from the nozzle onto the surface of the rotary cooling body, the molten alloy jetted from the nozzle comes into contact with the rotary cooling body. It is manufactured in an inert gas atmosphere of less than 60 torr or a reduced pressure atmosphere of 0.01 torr or less.

Here, it is particularly preferable that the reduced pressure or the inert gas atmosphere is set to 0.01 torr or less and 60 torr or less, respectively.
This is because when making a wide ribbon of 1.5 mm or more, it is thin and has excellent surface properties, and it is possible to obtain a pinhole-free product. Outside this range, there are waviness (unevenness) in the width direction and many pinholes. Or, a ribbon of 10 μm or less cannot be obtained. The inert gas is preferably He or Ar, more preferably He.

Further, the roll material is Fe alloy having the alloy composition of the present invention.
Since it is a base, an Fe-based alloy or a Cu-based alloy (brass or the like) is preferable, and this makes it possible to obtain an alloy having excellent surface properties and an extremely thin plate thickness.

Further, in the slit shape at the tip of the nozzle, a in FIG. 3 determines the width of the obtained ribbon, and can be set to an appropriate value of 2 mm or more. Further, b is an important value that determines the thickness of the thin strip and is preferably 0.2 mm or less,
Furthermore, 0.15 mm or less is preferable for producing an ultrathin ribbon.

The roll peripheral speed may be 10 m / s or more,
It is preferably 0 m / s or more. Injection pressure is used to make ultra-thin ribbon
It should be 0.05 kg / cm ² or more, preferably 0.025 kg / cm
^{It is 2} or less, more preferably 0.020 kg / cm ² or less, but if it is less than 0.001 kg / cm ^2, it is difficult to inject the molten metal.

The amorphous alloy ribbon obtained as described above is wound or laminated to form a magnetic core shape, subjected to strain relief heat treatment, and then cooled at a cooling rate of 0.5.
It may be in the range of deg / min to underwater quenching, preferably 1
~ 50deg / min.

After this, as heat treatment, heat treatment in a non-magnetic field or in a magnetic field (thin ribbon axis direction, width direction, plate thickness direction, rotating magnetic field heat treatment) may be further added. The atmosphere in these heat treatments is not particularly limited, and may be an inert gas such as N ₂ or Ar, a vacuum, a reducing atmosphere such as H _2, or the atmosphere.

[0021]

Embodiments of the present invention will be described below.

Example 1 An alloy composition of (Fe _0.96 Cr _0.02 Mo _0.02 ) ₇₇ Si ₁₀ B ₁₃ was prepared and melted to obtain a master alloy for producing an amorphous alloy. The nozzle shape used had a slit of 5 mm × 0.15 mm, and Fe was used as the roll material in the production of the amorphous alloy.
Using the, put the single roll device in the chamber and 5 × 10 ^-5 to
After pre-evacuating to rr, He gas was filled up to 30 torr.
Roll peripheral speed is 57m / sec, injection gas pressure is 0.02kg / cm ²
As a result, when the molten metal was rapidly quenched, a long ultrathin amorphous alloy ribbon having a plate thickness of 4.8 to 5.2 μm and a width of 4.8 mm with good surface property was obtained.

In the vacuum exhaust state by the same means (5 × 10 ^-5
The same ultra-thin ribbon without pinholes was obtained even when an amorphous alloy was produced by the torr) method.

For comparison, an alloy composition of Fe ₇₇ Si ₁₀ B ₁₃ was tried to be ultrathin under the same production conditions, but the molten metal could not be ejected and the slit size was changed to about 12 μm.
m was the minimum value.

The ultrathin amorphous alloy ribbon obtained in the example was formed into a toroidal shape and then subjected to strain relief heat treatment,
The magnetic properties were evaluated. The iron loss under the measurement condition of 1MHz, 0.1T is
1.7W / cc, which is about 1/4 of the comparative example 6.2W / cc. Also, the same value was obtained when W was used instead of Mo.

When the frequency characteristic of magnetic permeability was measured using an impedance analyzer, it was 800 at 10 MHz, which was about 5 times that of 150 of the comparative example.

Transformer, noise filter, saturable reactor, small inductor element for reducing spike noise, zero-phase current transformer, reactor for semiconductor circuit, magnetic core for magnetic head,
In the sensor, when the ultrathin amorphous alloy of the present invention is used, a transformer having excellent characteristics, a noise filter, a saturable reactor, a small inductor element for reducing spike noise, a zero-phase current transformer, a semiconductor circuit reactor,
A magnetic core for a magnetic head and a sensor were obtained.

Examples 2, 3 (Fe _0.97 Nb _0.03 ) ₈₃ (Si _0.3 B _0.3 ) ₁₇ and (Fe _0.70
A long ultrathin amorphous alloy ribbon having a composition of Ni _0.30 ) ₇₈ (Si _0.4 B _0.6 ) ₂₂ was produced under the same conditions as in Example 1. The obtained ribbons have a thickness of 7.2 μm and a width, respectively.
The thickness was 4.8 mm, the plate thickness was 7.4 μm, and the width was 4.8 mm.

Next, these thin strips were cut to an outer diameter of 12 mm and an inner diameter of 8 mm.
After being wound into a toroidal shape, heat treatment was performed. The former is
After heat treatment at 440 ° C. for 30 minutes, it was gradually cooled. After heat treatment at 400 ° C. for 40 minutes, the latter was heat treated at 250 ° C. for 1 hour by applying a magnetic field of 1 kOe in the width direction of the ribbon.

The high frequency loss of the core thus obtained was measured under the conditions of 1 MHz and 0.1T. As a result, in the former
Low loss of 1.5 (W / CC) and 1.4 (W / cc) were obtained in the latter.
These cores were incorporated as the main transformer of a switching power supply operating at 1MHz, and the operating characteristics were evaluated. For comparison, MnZn ferrite with the same cross-sectional area was used. as a result,
Compared to the comparative example, the power supply efficiency is improved by 1.8% and 2.0% respectively, and the core temperature rise during operation is 28%.
Decrease of ℃, 35 ℃ was seen. In addition, these cores 1MHz
Even when used as a choke coil for a switching power supply that operates, the temperature symptoms are 12 ° C,
It could be reduced by 15 ℃.

[0031]

As described above, according to the present invention, an amorphous alloy having an extremely thin plate can be directly obtained from a molten state, and by using this amorphous alloy, a magnetic core having excellent high frequency magnetic characteristics can be obtained. , Saturable reactors, various reactors such as semiconductor circuit reactors, noise filters (common mode, normal mode, high voltage pulse), main transformers, magnetic cores used at high frequencies such as magnetic heads, or sensors (current direction, Suitable for pressure).

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a noise filter.

FIG. 2 is a schematic view of an apparatus for producing an amorphous alloy by a single roll method.

FIG. 3 is a plan view of a slit used in an apparatus for producing an amorphous alloy.

Claims (9)

[Claims] 1. A general formula: (Fe _1-x M _x ) _100-z Y _z (wherein M is selected from Cr, Mo, W, Cr + Mo, Cr + W, Cr + Mo + W 1 , Y is at least one selected from Si, B, P, and C, and x and z are 0.01 ≦ x ≦ 0.1, 15 ≦ z ≦ 30.
An ultrathin amorphous alloy with high magnetic permeability and low iron loss, which is characterized by having a plate thickness of 10 μm or less. 2. The ultrathin amorphous alloy with high magnetic permeability and low iron loss according to claim 1, which is used for a transformer. 3. The ultrathin amorphous alloy having a high magnetic permeability and a low iron loss according to claim 1, which is used for a noise filter. 4. The ultrathin amorphous alloy with high magnetic permeability and low iron loss according to claim 1, which is used for a saturable reactor. 5. The high magnetic permeability according to claim 1, which is used for a small inductor element for reducing spike noise.
Ultra-thin amorphous alloy with low iron loss. 6. The ultrathin amorphous alloy with high magnetic permeability and low iron loss according to claim 1, which is used for a zero-phase current transformer. 7. The ultrathin amorphous alloy with high magnetic permeability and low iron loss according to claim 1, which is used for a reactor for semiconductor circuits. 8. The ultra-thin amorphous alloy having a high magnetic permeability and a low iron loss according to claim 1, which is used for a magnetic core for a magnetic head. 9. The ultrathin amorphous alloy with high magnetic permeability and low iron loss according to claim 1, which is used for a sensor.