JPH08229642A - 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: [(Co _1-x Fe _x ) _{1- y My} ]
_100-z Y _z (where M is Cr, Mo, W, Cr + Mo, Cr + W, C
One is selected from r + Mo + W, Y is one or more selected from Si, B, P and C, and x, y and z are 0.02 ≦ x ≦ 0.
1, 0.005 ≤ y ≤ 0.1, 18 ≤ z ≤ 30), and is an ultrathin amorphous alloy with a high magnetic permeability and low iron loss, having a plate thickness of 10 µm or less.

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 the general formula: [(Co _1-x Fe _x ) _1-y M _y ] _100-z Y _z (where M is Cr, Mo , W, Cr + Mo, Cr + W, Cr + Mo + W, Y represents one or more selected from Si, B, P, and C, and x, y, and z are 0.02 ≦ x. ≤0.1, 0.005
≤ y ≤ 0.1, 18 ≤ z ≤ 30), and is an ultrathin amorphous alloy with high magnetic permeability and low iron loss characterized by 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. Fe is an element that controls magnetostriction, and x that regulates the Fe content is in the range of 0.02 to 0.1. Preferably 0.
It is 03 to 0.08, and more preferably 0.04 to 0.07.

[0013] M is an element effective in reducing the viscosity during melting of the alloy, improving the wettability with the roll, and improving the surface properties of the alloy, but if the amount is too small, the effect of addition cannot be obtained, and It is difficult to obtain an ultrathin ribbon, and on the contrary, if it is too much, the Curie temperature becomes low, and the improvement effect due to addition cannot be seen. Therefore, the range of y that defines M is 0.005 to 0.1. It is preferably 0.01 to 0.08, and more preferably
It is 0.01 to 0.06.

Y is an element necessary for amorphization, but if it is too small, it is difficult to amorphize, and if it is too large, the Curie temperature becomes too low. Therefore, the range of z that defines the Y amount is 18 to 30. Set to atomic%. Preferably
20 to 28 atom%.

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 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.

The roll material is Co alloy of the present invention.
Since it is a base material, the use of Fe-based alloys gives 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, 2
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. The cooling rate is 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.

[0022]

Embodiments of the present invention will be described below.

Example 1 [(Co _0.94 Fe _0.06 ) _0.95 M _0.05 ] ₇₄ (Si _0.5 B _0.5 ).
_An alloy composition of ₂₆ (where M is selected from Cr, Mo, and W) was prepared and melted to obtain a mother alloy for producing an amorphous alloy. The nozzle shape used has a slit of 5 mm × 0.15 mm, Fe is used as the roll material, this single roll device is put in the chamber and pre-evacuated to 5 × 10 ^-5 torr, then He gas is filled up to 30 torr did. Roll speed of 57m / s
and ec, the injection gas pressure of 0.02 kg / cm ^2, was rapid quenching of molten metal, the surface of good thickness 4.8 to 5.2 .mu.m
A long ultrathin amorphous alloy ribbon with a width of 4.8 mm 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.

The ultrathin amorphous alloy containing Cr (thickness: 4.9 μm) of the present invention was wound and then subjected to strain relief heat treatment to measure the frequency characteristic of initial permeability and high frequency iron loss. FIG. 4 shows frequency characteristics of magnetic permeability with an excitation magnetic field of 2 mOe. For comparison, the results of an amorphous alloy thin film having the same composition and a plate thickness of 15 μm are also shown in FIG. As is clear from the figure, the effect of the plate thickness is remarkable when the magnetic permeability is 100 kHz or more, and the 4.9 μm amorphous alloy of the present invention is about 4 times at 1 MHz and about 5 times at 10 MHz compared to the comparative example. There is. Also,
About the ultra-thin amorphous alloy with Cr added, 0.1MH
When the iron loss was measured under the conditions of z and 0.1T, it was 1.4W / cc
Met. Similar values were obtained for alloys containing Mo and W instead of Cr. On the other hand, the amorphous alloy of 15 μm in the comparative example had 3.6 W / cc.

For comparison, an alloy composition of Fe ₇₇ Si ₁₀ B ₁₃ was attempted to be extremely thin under the same manufacturing conditions as in this example, but the molten metal could not be ejected and the slit dimensions were changed. The minimum value was about 12 μm.

Examples 2 to 6 Co-based amorphous alloy ribbons of each composition shown in Table 1 were changed in the roll peripheral speed in the range of 30 m / sec to 50 m / sec, and other conditions were fixed as follows. It was made. That is, the nozzle shape is 5 mm × 0.15 mm, the roll material is Fe, and the quenching atmosphere is 10
^The pressure was reduced to ^-4 torr, the injection pressure was 0.01 kg / cm ² , and the gap between the nozzle and the roll was 0.15 mm. The thickness of each Co-based amorphous alloy ribbon thus obtained is shown in Table 1.
It was as shown in. Also, each of these Co-based amorphous alloy ribbons is wound around an outer diameter of 12 mm x an inner diameter of 10 mm to form a magnetic core,
After subjecting these to strain-relieving heat treatment, a heat treatment was carried out for 1 hour at a temperature below the Curie temperature while applying a magnetic field of 500 Oe in the width direction of the ribbon. In Examples 3 and 4, the heat treatment for strain relief was not performed, and the heat treatment was performed at 250 ° C. for 1 hour while applying a magnetic field of 500 Oe in the width direction of the ribbon.
Then, the iron loss of 1 MHz and 0.1 T was measured. In addition, we incorporated it as a main transformer of a switching power supply operating at 1MHz and evaluated the power supply efficiency and the temperature rise of the magnetic core during operation.
The results are also shown in Table 1.

[0028]

[Table 1] As is clear from Table 1, each of the main transformers according to Examples 2 to 6 is effective in increasing the efficiency of the power supply.
As a comparative example, the same evaluation was performed on a main transformer using ferrite, but a decrease in efficiency was observed.

In addition to the above-mentioned transformer, 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 head magnetic core, a sensor, and the ultrathin amorphous alloy of the present invention. By using, the noise filter, the saturable reactor, the small inductor element for reducing spike noise, the zero-phase current transformer, the semiconductor circuit reactor, the magnetic core for the magnetic head, and the sensor having excellent characteristics were obtained.

Example 7 A long ultrathin amorphous alloy ribbon having a composition of (Co _0.90 Fe _0.05 Cr _0.03 Nb _0.02 ) ₇₅ (Si _0.5 B _0.5 ) ₂₅ was prepared under the same conditions as in Example 1. The obtained ribbon has a plate thickness of 7.0 μm,
The width was 4.8 mm.

Next, the thin ribbon was wound into a toroidal shape having an outer diameter of 10 mm, an inner diameter of 6 mm, an outer diameter of 4 mm and an inner diameter of 2 mm, respectively, and then heat-treated at 440 ° C. for 30 minutes and then gradually cooled.

The high frequency loss of the core thus obtained was measured under the condition of 1 MHz and 0.1T. As a result, 1.0 (W / CC)
It was confirmed that a low loss was obtained.

This core is incorporated as a saturable core of a switching power supply operating at 1 MHz and the effect as an output control element and the effect as an ultra-small inductor element for spike noise reduction in series with a switching element Was evaluated. For comparison, the former uses a 5 μm permalloy core with the same cross-sectional area and the latter uses MnZn.
Ferrite was used. In addition, these cores are 2.5 W / cc and 2.8 W / cc, respectively, when measured under the same conditions.

As a result, the efficiency of the saturable core is 1.
It was confirmed that the temperature rise during operation was reduced by 16 ° C while being improved by 2%. On the other hand, regarding the effect of the ultra-small inductor element for spike noise reduction, the noise level at the output is reduced by 25 mVp-p compared to the comparative example, which is effective in suppressing noise and increases the core temperature during operation. It was reduced by 18 ℃, and the effect of low loss was seen.

[0035]

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.

FIG. 4 is a diagram showing frequency characteristics of magnetic permeability of an ultrathin amorphous alloy according to an example of the present invention.

Claims (9)

[Claims] 1. A general formula: [(Co _1-x Fe _x ) _{1- y My} ]
_100-z Y _z (wherein M is one selected from Cr, Mo, W, Cr + Mo, Cr + W, Cr + Mo + W, Y is selected from Si, B, P, C 1 X, y, and z are 0.02 ≤ x ≤ 0.1, 0.005 ≤ y ≤ 0.1, and 18 ≤ z ≤ 30), and the plate thickness is 10 μm or less. Ultra-thin amorphous alloy with high magnetic permeability and low iron loss. 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.