JP2677405B2 - Method for improving magnetic properties of ultrafine crystal alloy ribbon core - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for improving magnetic characteristics of an ultrafine crystal alloy ribbon magnetic core used in various parts such as a transformer, a saturable reactor, and a choke coil.

[Prior Art] Fe-Cu with at least 50% of the structure consisting of fine crystal grains
A-(Si, B) -M system (M is an element such as Nb, W, Ta, etc.) Fe-based soft magnetic alloy is disclosed in EP-A-0271657.

This alloy, despite being Fe-based, has low magnetostriction,
Moreover, the soft magnetic characteristics were excellent.

It is also disclosed in the above-mentioned publication that the Fe-based soft magnetic alloy can obtain a structure composed of fine crystal grains by heat treatment after obtaining an amorphous alloy.

[Problems to be Solved by the Present Invention] Since the Fe-Cu- (Si, B) -M Fe-based soft magnetic alloy has a crystallized structure, it is brittle when processed into a magnetic core. It is manufactured by winding and processing in the state of the amorphous alloy before heat treatment which has not been transformed.

The effective magnetic permeability of the magnetic core thus obtained may be lower than that of a magnetic core that is simply laminated without winding.

In view of the above problems, the present invention is to provide a method for improving the magnetic characteristics of an ultrafine crystal alloy ribbon magnetic core that can obtain a wound magnetic core of the Fe-Cu-M system having a high effective magnetic permeability.

[Means for Solving the Problems] In the present invention, Fe, Cu and M (where M is Nb, W, Ta, Zr, H
At least one element selected from the group consisting of f, Ti and Mo) is contained as an essential element, and at least 50% of the structure is composed of ultrafine crystalline alloy ribbons composed of fine crystal grains with a grain size of 500Å or less. A method for improving magnetic properties of an ultrafine crystal alloy ribbon magnetic core, which is characterized by deforming the magnetic core once and then returning it to its original shape, or Fe, Cu and M (where M is Nb, W, Ta, Zr, H
At least one element selected from the group consisting of f, Ti and Mo) is contained as an essential element, and at least 50% of the structure is composed of ultrafine crystalline alloy ribbons composed of fine crystal grains with a grain size of 500Å or less. A method for improving magnetic characteristics of an ultrafine crystal alloy ribbon magnetic core, characterized by applying vibration to the magnetic core.

In the present invention, it is preferable to contain Si, B or the like as an amorphization promoting element in addition to the above elements.

Further, Cu and M are elements necessary for refining the structure of the alloy, and these elements can provide high effective magnetic permeability.

The present invention is based on the finding that the soft magnetic characteristics can be remarkably improved by returning the magnetic core formed of the ultrafine crystal alloy ribbon to its original shape after deformation or by vibrating it.

To deform, for example, crush the magnetic core,
There is a method of giving vibration.

[Examples] Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 Cu1%, Nb3%, Si14%, B8.5% in atomic% balance Fe substantially
The alloy melt consisting of is rapidly cooled by the single roll method to a thickness of 19μ
An amorphous alloy ribbon with m and width of 15 mm was prepared.

Next, the toroidal wound magnetic core having the shape shown in FIG. 1 (a) was produced by winding the thin ribbon so that the surface in contact with the roll was outside and the outer diameter (D1) was 20 mm and the inner diameter (D2) was 10 mm.

Next, this magnetic core was placed in a tubular furnace in which nitrogen gas was flown, heated from room temperature at a heating rate of 2.5 / min, held at 550 ° C. for 40 minutes, taken out of the furnace and air-cooled.

After the heat treatment, the magnetic core material was observed by a transmission electron microscope to observe the microstructure and X-ray diffraction.
It was confirmed to consist of ccFe solid solution grains.

Next, put this winding core in a phenol resin core case and wind the winding to remove the core loss at 100 KHz, 2KG Pc ₂ /
₁₀₀ k, was measured the effective μe ₁₀₀ k in 100KHz.

Pc _2/100 k is 610mW / cc, μe ₁₀₀ k was 5200.

Next, take out this winding core from the core case, crush it until the outer diameter (D1) becomes about 15 mm as shown in Fig. 1 (b), and then restore it to its original shape. The above characteristics were measured repeatedly.

Pc _2/100 k is 300mW / cc, μe ₁₀₀ k is 18000, was improved remarkably high frequency magnetic properties.

It is considered that the reason why the soft magnetic characteristics can be improved is that the electrical conduction between the layers of the magnetic core is reduced and the magnetic core loss due to the eddy current loss is reduced.

Example 2 Cu1%, Nb5%, Si13%, B8.5% balance atomically Fe
The alloy melt consisting of is rapidly cooled by the single roll method to a thickness of 18μ.
An amorphous alloy ribbon with m and width of 12.5 mm was prepared.

Next, this ribbon was wound around an outer diameter (D1) of 25 mm and an inner diameter (D2) of 15 mm with the roll contact surface on the inside, and after forming a winding magnetic core, this magnetic core was formed into a tubular furnace with a solenoid coil flowed with Ar gas. About 4000 in the direction perpendicular to the magnetic path of the insert core (width direction of the ribbon)
While applying a magnetic field of Oe, the temperature was raised from room temperature at a heating rate of 2 ° C / min, held at 590 ° C for 1 hour, and then cooled at a cooling rate of 2 ° C / min.
It was cooled to 00 ° C., the magnetic field was cut off, taken out of the furnace and air-cooled to room temperature. The microstructure was the same as that of Example 1 as a result of the structure observation by a transmission electron microscope.

100 KHz, core loss Pc _2/100 k in 2KG is 560 mW / cc, 100
The effective permeability μe ₁₀₀ k at KHz was 6200.

Next, this wound magnetic core has an outer diameter (D1) of about 15 as in the first embodiment.
After crushing to mm, the step of returning to the original shape was repeated by shifting the crushing position by 90 degrees, and the above characteristics were measured.

Pc _2/100 k is 290mW / cc, μe ₁₀₀ k is the 19600 has been significantly improved.

Example 3 Cu 1.5%, Mo 3%, Cr 0.5%, Si 14%, B 7.8% in atomic% The remaining molten alloy consisting essentially of Fe was rapidly cooled by a single roll method to obtain a thickness of 22 μm and a width of 25 mm. An amorphous alloy ribbon was produced.

Next, this ribbon was wound with the roll contact surface inside and a wound magnetic core with an outer diameter (D1) of 100 mm and an inner diameter (D2) of 80 mm was produced.

Next, a heat-resistant wire was used to wind a current around this winding core, and a current was passed through the winding core. After warming and holding for 1 hour, it was cooled to room temperature at an average cooling rate of about 2.5 ° C./min.

The core loss of heat treated core is 150mW / c at 20KHz, 2KG
c. The microstructure was the same as in Example 1.

Next, fix a part of the outer peripheral surface of this magnetic core on the diaphragm, and
The diameter direction (D1 direction) of the magnetic core in Fig. 1 at 0 cpm and an amplitude of 10 mm
I gave a vibration to. After oscillating for 10 minutes, the value of the core loss was reduced to 80 mW / cc when measured again. The magnetic characteristics can be improved by vibrating in this manner.

Example 4 A molten alloy having the composition shown in Table 1 was rapidly cooled with a single roll to produce an amorphous alloy ribbon having a thickness of 18 μm and a width of 12.5 mm.

Next, with this ribbon, with the roll contact surface facing outside, the outer diameter (D1) 25
mm, the inner diameter (D2) was 15 mm, and a wound magnetic core was produced.

Next, while putting this wound magnetic core in a furnace kept at 450 ° C in which nitrogen gas was flown, while applying a magnetic field of about 3500 Oe in the direction perpendicular to the magnetic furnace,
After cooling to 450 ° C at a cooling rate of 2.5 ° C / min, the magnetic field was removed from the furnace and forced air cooling to room temperature. After this heat treatment, the deformation step of crushing the outer diameter (D1) to about 15 mm and returning it to the original state was repeated by shifting by 90 degrees in the same manner as in Example 1. Effective magnetic permeability immediately after heat treatment, After the deformation process, the effective magnetic permeability μe ₁₀₀ k at ₁₀₀ KHz was measured. Table 1 shows the results. The microstructure was composed of crystal grains having a grain size of 500Å or less as in Example 1.

It can be seen that by providing the deformation step, the effective magnetic permeability is remarkably improved and it is a very effective method for improving the high frequency magnetic characteristics.

[Advantages of the Invention] According to the present invention, the high-frequency magnetic characteristics of the ultrafine crystal alloy ribbon magnetic core can be easily improved, so that the effect is remarkable.

[Brief description of the drawings]

FIG. 1 (a) is a schematic view showing an example of the shape of the magnetic core made in the present invention, and FIG. 1 (b) is a schematic view for explaining the method of the present invention for deforming the magnetic core. D1: outer diameter, D2: inner diameter

Front Page Continuation (72) Inventor Noriyoshi Hirao 5200 Mikashiri, Kumagaya City, Saitama, Hitachi Metals Co., Ltd. Magnetic Materials Research Laboratory (56) Reference JP-A-63-302504 (JP, A) JP-A-60-250605 ( JP, A) JP 63-239906 (JP, A) JP 62-56203 (JP, B2)

Claims (2)

(57) [Claims] 1. Fe, Cu and M (where M is Nb, W, Ta, Zr, H
At least one element selected from the group consisting of f, Ti and Mo) is contained as an essential element, and at least 50% of the structure is composed of ultrafine crystalline alloy ribbons composed of fine crystal grains with a grain size of 500Å or less. A method for improving magnetic characteristics of an ultrafine crystal alloy ribbon magnetic core, which comprises deforming the magnetic core once and then returning it to the original shape. 2. Fe, Cu and M (where M is Nb, W, Ta, Zr, H
At least one element selected from the group consisting of f, Ti and Mo) is contained as an essential element, and at least 50% of the structure is composed of ultrafine crystalline alloy ribbons composed of fine crystal grains with a grain size of 500Å or less. A method for improving magnetic properties of an ultrafine crystal alloy ribbon magnetic core, characterized by applying vibration to a magnetic core.