KR0140788B1 - Ultrathin fe based nanocrystalline alloys and method for preparing ultrathin ribbons - Google Patents

Abstract

The present invention relates to a method for producing an iron-based ultra-thin ultrafine crystal alloy having low magnetic loss and excellent high-frequency characteristics, and a method for producing the ultra-thin thin ribbon, which is represented by the following compositional formula and has an average particle diameter of 5 to 20 nm.

Fe _100-xyzw B _w Nb _y Cu _z M _w

Wherein M is at least one element selected from Al, Si, Ti, V, Cr, Mn, Co, Ni, Y, Zr, Mo, Hf and Ta, and x, y, z and w are each 5% as atoms X? 15, 5? Y? 15, 0? Z? 5, 0? W? 5 and 10? X + y + z + w?

Description

Manufacturing method of ultra-thin iron-based ultrafine crystalline alloy and ultra-thin thin ribbon

1 is a graph showing the thickness change of the thin ribbon according to the injection pressure (0.16kg / cm ² ) of the iron-based ultrafine crystal alloy according to the present invention.

2 is a graph showing the thickness change of the thin ribbon according to the linear velocity of the molten metal cooling roll of the iron-based ultra-fine crystal alloy according to the present invention.

3 is a graph showing the change in core loss (measured at 100 kHz, 0.2T condition) according to the thickness of the iron-based ultrafine crystal alloy ribbon prepared by the single roll type liquid quenching method according to the present invention.

4 is a graph showing the change in the effective permeability according to the frequency of the iron-based ultrafine crystalline alloy ribbon prepared by a single roll liquid quenching method according to the present invention.

5 is a graph showing the change of magnetic core loss (measured at 1 MHz, 0.2T condition) according to the thickness of the iron-based ultrafine crystal alloy ribbon prepared by the single roll type liquid quenching method according to the present invention.

6 is a graph showing the thickness change of the thin ribbon according to the injection pressure (0.16kg / cm ₂ or more) of the iron-based ultrafine crystal alloy according to the present invention.

The present invention relates to an ultra-thin iron-based ultrafine crystal alloy exhibiting low core loss and excellent high frequency characteristics and a method for producing the ultra-thin thin ribbon. More specifically, the present invention is a method for producing an iron-based ultra-fine crystalline alloy ultra-thin ribbon having a thickness of 3 to 12㎛ by appropriately controlling various manufacturing parameters in the production of amorphous ribbon by the liquid quenching method using an iron-based alloy. It is about.

Amorphous magnetic alloy thin ribbons prepared by the liquid quenching method were developed in the 1970s and have been actively studied as new soft magnetic materials. These amorphous materials can be broadly classified into iron-based and Co-based materials. Iron-based amorphous alloys with high saturation magnetic flux densities have been studied for practical application as commercial core transformer core materials. System amorphous alloys are widely used in the field of magnetic components for switching power supplies operating in the several 100 kHz band.

Recently, the demand for miniaturization and high frequency for the power supply for electronic devices is increasing more and more according to the light and small size miniaturization of various electronic devices. Accordingly, in the case of high frequency magnetic cores using Co-based amorphous alloy thin ribbons Much research has been done to bring the operating frequency up to the 1 kHz band.

As a result of these studies, ultra-thin Co-based amorphous alloy ribbons having a thickness of 10 µm or less, which is much thinner than the thickness of conventional quenching ribbons, have recently been produced. It has been reported to have been improved (Japanese Patent Laid-Open No. 3-90547). The background of this study is that in the case of metal magnetic core, the eddy current loss accounts for most of the magnetic losses generated at the high frequency. Therefore, it is necessary to reduce the eddy current loss to improve the high frequency characteristics. According to the classical theory, the eddy current loss (We) can be expressed as

We = (πtfBm) ² 6ρ

Where t is thickness, f is operating frequency, Bm is maximum induced magnetic flux, and p is electrical resistance. Therefore, this equation suggests that it is possible to reduce the magnetic core loss by reducing the thickness of the ribbon.

However, Co-based amorphous alloys, which have been the subject of ultra-thin thin ribbons, have excellent qualities, but not only low saturation density, but also high price of Co and local ubiquitous resources may cause supply instability. I think. The inventors have selected a composition of an iron-based ultrafine crystal alloy that has high magnetic flux density and excellent magnetic properties of low coercivity for overcoming these shortcomings and for a wider range of applications. In spite of the physical properties of the present invention, a new ultra-thin iron-based ultrafine crystal alloy was attempted by appropriately controlling the production conditions of the ribbon.

In view of the above-mentioned matters, the inventors of the present invention have prepared a molten iron-based ultrafine crystalline alloy composition into an ultra-thin amorphous thin ribbon by a single-roll liquid quenching method, and then heat-treats it under appropriate conditions to obtain a high-frequency magnetic property. We have developed a new ultra-thin alloy manufacturing method which is significantly improved compared to the ultrafine crystalline alloy with excitation.

It is an object of the present invention to provide an ultra-thin iron-based ultrafine crystalline alloy exhibiting low core loss and excellent high frequency characteristics and a method for producing the ultra-thin thin ribbon.

The object of the present invention is achieved by providing an ultra-thin iron-based alloy, which is represented by the following compositional formula and is characterized by crystal grains having an average particle diameter of 5 to 20 nm.

Fe _100-xyzw B _w Nb _y Cu _z M _w

Where M is at least one element selected from Al, Si, Ti, V, Cr, Mn, Co, Ni, Y, Zr, Mo, Hf and Ta, and x, y, z and w are each 5% as atoms X? 15, 5? Y? 15, 0? Z? 5, 0? W? 5 and 10? X + y + z + w?

If x is 5 or less, amorphous cannot be obtained in the quench state, and if it is 15 or more, there is a risk of Fe-B compound formation. If y is less than 5, it is difficult to obtain amorphous in the quench state, and if 15 or more, Fe-Nb compound is precipitated. easy. And when z is 5 or more, it crystallizes and an amorphous phase is not obtained in a quenched state. In addition, when the w deviates from the proper composition region indicated for the purpose, the magnetic properties are drastically lowered.

Preferably the present invention preferably comprises M selected from Al, Mo and Cr, 8 ≦ x ≦ 10, 6 ≦ y ≦ 8, 0.5 ≦ z ≦ 2.0, 0.5 ≦ w ≦ 1.5, in particular x = 9, y = 7, z = 1 and 0.5 ≦ w ≦ 1.5.

In addition, the thickness of the alloy of the present invention is present in the range of 3 to 12 μm by controlling the appropriate liquid quenching conditions.

In addition, the present invention

1) dissolving the master alloy of the above formula in a known vacuum arc furnace to obtain a molten metal,

2) When the molten metal reaches 1,000 ~ 1,500 ° C, the molten metal spraying pressure is 0.01-0.3kg / cm ² , the linear velocity of the cooling roll is 30-65m / s according to the known single roll type liquid quenching method, Preparing a thin ribbon with a vacuum degree of 5 × 10 ⁻² Torr or less, and

3) The present invention relates to a method for producing an iron-based ultra-thin ultra-fine crystal alloy ribbon, comprising the step of heat-treating the ribbon in vacuum.

In the production method of the present invention, the rectangular nozzle width of the quartz tube is 0.1 to 0.25 mm. In single roll liquid quenching, the degree of vacuum in the molten metal spray chamber of the quenching device is preferably ⁵ x 10 ^-5 Torr or less. And the quartz tube nozzle injection pressure becomes like this. Preferably it is 0.02-0.16 kg / cm <^2> , and the linear velocity of a molten metal cooling roll becomes like this. Preferably it is 35-60 m / s. After the ultra-thin thin ribbon is manufactured, heat treatment is generally performed at about 500 to 650 ° C. for about 20 to 120 minutes, and preferably at 520 to 580 ° C. for 60 minutes.

According to the present invention, in order to manufacture an ultra-thin ribbon having a thickness of 3 to 12 μm, the shape and dimensions of the spray nozzle, the temperature of the molten metal, the degree of vacuum in the molten metal spray chamber, the spray pressure of the molten metal, the linear velocity of the cooling roll, etc. Will be affected.

If other manufacturing conditions are constant, the thickness of amorphous quenching strip can be controlled by changing the injection pressure of the molten metal and the linear speed of the cooling roll, but the reduction of the excessive injection pressure to reduce the thickness of the ribbon is excessively small or The clogging of the injection nozzle is concerned, and the increase in the linear velocity increases the vibration, which in turn causes adverse effects. Therefore, in the molten metal spray chamber maintained at 5x10 ^-5 Torr or less, the molten metal is applied 35 to 60 m / through the nozzle by applying an inert gas at an injection pressure of 0.02 to 0.16 kg / cm ² when the temperature is 1,000 to 1,500 ° C. When molten metal is sprayed on a steel cooling roll rotating at a linear speed of s, an ultrathin thin ribbon having the best thin surface roughness and thickness can be obtained.

As described above, the iron-based ultrafine crystalline alloy was controlled by controlling the linear velocity, vacuum degree, cooling roll and nozzle spacing, and melt temperature, etc. of a single roll to prepare a quench solidified thin ribbon. Excellent ultra-thin ribbons can be obtained.

Hereinafter, the present invention will be described in detail in the Examples.

Example 1

Using a vacuum arc furnace, a master alloy consisting of Fe 83 atom%, B 9 atom%, Nb 7 atom%, Cu 1 atom% and other unavoidable elements was prepared in a vacuum arc furnace. The prepared master alloy was placed in a quartz tube having a longitudinal nozzle, and an amorphous ultrathin ribbon having a thickness of 12 μm or less was prepared using a single roll liquid quenching apparatus capable of maintaining a vacuum and an inert atmosphere.

Specifically, after maintaining the inside of the quenching apparatus at 5x10 ^-5 Torr, when the molten metal temperature reaches 1000 ~ 1500 ℃, 40 ~ 55m / through the nozzle by applying an inert gas at a spray pressure of 0.02 ~ 0.16kg / cm ² The molten metal was sprayed on the iron roll rotating at a linear speed of s. The thickness change of the amorphous ribbon according to the injection pressure is shown in FIG.

Example 2

To prepare an amorphous ultrathin ribbon having a thickness of 12 μm or less, the injection pressure of the molten metal through the nozzle was made constant and the linear speed of the cooling roll was changed to 35 to 65 m / s. The thickness change of the amorphous thin ribbon according to the linear velocity of the cooling roll at the injection pressure of a constant molten metal is shown in FIG.

Example 3

An ultra-thin ribbon of 12 µm or less was prepared in the same manner as in Example 1 except that the amorphous ribbon was heat-treated. Heat treatment was performed for 1 hour at 560 ° C. in a vacuum of 10 ⁻³ torr after winding a thin ribbon of an appropriate length in a copper bobbin having an outer diameter of 21 mm in a toroid shape. As a result of X-ray diffraction test and transmission electron microscopy, it was confirmed that the Bcc-Fe crystal phase composed of crystal grains of about 10 nm or less was transformed. The magnetic core loss of the sample was measured at 100kHz and 0.2T with BH analyzer (BH Analyzer, Iwatsu, SY820), and the change of magnetic core loss according to the thickness of the ribbon was shown in FIG.

Example 4

A thin ribbon having a thickness of 7 μm or less was produced in the same manner as in Example 1, and then heat-treated as in Example 3.

The effective permeability of the samples thus prepared was measured using an impedance analyzer, and the effective permeability according to the frequency change is shown in FIG.

Example 5

A thin ribbon having a thickness of 12 μm or less was prepared in the same manner as in Example 1, except that the heat treatment was performed as in Example 3.

The change of magnetic core loss of the sample thus prepared was measured under dynamic magnetization conditions of 1 MHz and 0.2T, and the magnetic core loss according to the thickness of the ribbon was shown in FIG. 5.

Example 6

Example 1 except that a mother alloy composed of Fe 81.5-82.5%, B9 atomic%, Nb7 atomic%, Cu1 atomic%, Al, Mo or Cr0.5-1.5 atomic%, and other unavoidable elements In the same manner, a thin ribbon having a thickness of 12 µm or less was prepared, and then heat-treated as in Example 3.

The magnetic core loss of the sample thus obtained was measured, and the results are shown in Table 1 below.

Comparative Example 1

Samples were prepared in the same manner as in Example 1, except that the injection pressure of the molten metal through the rectangular nozzle was 0.16 to 1.5 kg / cm ² in order to manufacture an amorphous thin ribbon having a thickness of 12 μm or more.

The thickness change according to the molten metal injection pressure of the thin ribbon thus produced is shown in FIG.

Comparative Example 2

Samples were prepared in the same manner as in Example 1 except for maintaining the linear velocity of the rotating cooling roll at 30 m / s or less in order to prepare an amorphous thin ribbon having a thickness of 12 μm or more.

The thickness change of the amorphous ribbon according to the linear velocity of the cooling roll of the ribbon thus produced is shown in FIG.

Comparative Example 3

Samples were prepared and heat-treated in the same manner as in Example 3 except that the injection pressure of the molten metal through the rectangular nozzle was 0.16 to 1.5 kg / cm ² to prepare a thin ribbon having a thickness of 12 μm or more.

The magnetic core loss of the sample thus prepared was measured at 100 MHz and 0.2T dynamic magnetization conditions, and the change of magnetic core loss according to the thickness of the ribbon was shown in FIG.

[Comparative Example 4]

Samples were prepared and heat-treated in the same manner as in Example 3 except that the injection pressure of the molten metal was 0.8 kg / cm ² or more in order to prepare a thin ribbon having a thickness of 20 μm.

The change in the effective permeability according to the frequency change of the sample thus prepared is shown in FIG.

[Comparative Example 5]

Samples were prepared and heat-treated in the same manner as in Example 3 except that the injection pressure of the molten metal through the rectangular nozzle was 0.16 to 1.5 kg / cm ² to prepare a thin ribbon having a thickness of 12 μm or more.

The magnetic core loss of the sample thus prepared was measured at 1 MHz and 0.2T dynamic magnetization conditions, and the change of magnetic core loss according to the thickness of the ribbon was shown in FIG. 5.

Although the present invention has been specifically described in accordance with the above embodiments, it should not be construed that the present invention is limited by these examples. Those skilled in the art should recognize that various changes and modifications can be made without departing from the scope and spirit of the invention as set forth in the claims of the invention.

Claims (5)

An iron-based ultra-thin ultrafine crystal alloy having low magnetic loss and excellent high frequency characteristics, which is represented by the following compositional formula and has an average particle diameter of 5 to 20 nm. Fe _100-Xyzw B _x Nb _y Cu _z M _w Wherein M is at least one element selected from Al, Si, Ti, V, Cr, Mn, Co, Ni, Y, Zr, Mo, Hf and Ta, and x, y, z and w are each 5% as atoms X? 15, 5? Y? 15, 0? Z? 5, 0? W? 5 and 10? X + y + z + w? The alloy of claim 1, wherein M is selected from Al, Mo, and Cr, and x = 9, y = 7, z = 1, and 0.5 ≦ w ≦ 1.5. 1) dissolving an alloy represented by the following composition formula in a known vacuum arc furnace to obtain a molten metal Fe _100-Xyzw B _x Nb _y Cu _z M _w (Wherein, M is at least one element selected from Al, Si, Ti, V, Cr, Mn, Co, Ni, Y, Zr, Mo, Hf and Ta, x, y, z and w are each atom% 5≤x≤15, 5≤y≤15,0≤z≤5, 0≤w≤5 and 10≤x + y + z + w≤40), 2) When the molten metal reaches 1,000 to 1,500 ° C, the molten metal spray pressure is 0.01 to 0.16 kg / cm ² , the linear velocity of the cooling roll is 30 to 65 m / s, and the molten metal is sprayed according to a known single-roll liquid quenching method. Preparing a thin ribbon using a vacuum degree of the room at 5x10 ^-2 Torr or less, and 3) A method of manufacturing an iron-based ultra-thin ultrafine crystalline alloy ribbon having low magnetic loss and excellent high frequency characteristics, comprising: heat treating the ribbon for 20 to 120 minutes at about 500 to 650 ° C. in a vacuum. The method according to claim 3, wherein the melt injection pressure is set to 0.02 to 0.16 kg / cm ² . The method according to claim 3, wherein the linear speed of the cooling roll is set to 35 to 60 m / s.