KR102268103B1 - Fe BASED NANO-STRUCTURED SOFT MAGNETIC ALLOY RIBBON AND METHOD FOR PREPARING THE SAME - Google Patents

Abstract

The present invention relates to a Fe-based soft magnetic alloy ribbon having a higher saturation magnetic flux density than a conventional nanocrystalline soft magnetic alloy, and excellent permeability and core loss characteristics at high frequencies, and a method for manufacturing the same. Specifically, it relates to a Fe-based nanocrystalline soft magnetic alloy ribbon for a wireless charging module and a method for manufacturing the same. Preferably, the present invention is a nanocrystalline soft magnetic alloy ribbon having a composition in which calcium (Ca) is added to an iron (Fe)-based alloy, silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at% , Copper (Cu) 0.1 ~ 3 at%, calcium (Ca) 0.005 ~ 2.0 at% and iron (Fe) characterized in that the remaining amount, it provides a nanocrystalline soft magnetic alloy ribbon.

Description

Fe BASED NANO-STRUCTURED SOFT MAGNETIC ALLOY RIBBON AND METHOD FOR PREPARING THE SAME

The present invention relates to a Fe-based soft magnetic alloy ribbon having a higher saturation magnetic flux density than a conventional nanocrystalline soft magnetic alloy, and excellent permeability and core loss characteristics at high frequencies, and a method for manufacturing the same. Specifically, the present invention relates to a Fe-based nanocrystalline soft magnetic alloy ribbon for a wireless charging module and a method for manufacturing the same.

The electromagnetic induction type wireless power transmission reception module is generally manufactured by stacking a reception antenna of a flexible printed circuit board (FPCB) on a substrate on which ferrite and an amorphous sheet are laminated in the form of a coil. Recently, these materials are being replaced by thin sheets of nanocrystalline soft magnetic material (thickness of about 0.3 mm or less) with low magnetic permeability and low core loss. In this case, an induced current flows from the receiving antenna through the magnetic field generated by the transmitter, making it possible to charge the battery and receive data. At this time, the high-performance soft magnetic sheet plays a role of shielding and absorbing electromagnetic waves and receives the surrounding magnetic field due to its high magnetic permeability. It plays a role (Power Charger Enhancer) that increases the transmission efficiency by drawing it into the module and increasing the density of the magnetic flux.

Existing magnetic induction wireless charging modules cannot prevent excessive heat generation and shortening of the lifespan of the charging module due to a surge in eddy current loss, which causes a sharp decrease in the accuracy and transmission distance of NFC transmission data. The currently used nanocrystalline soft magnetic sheet is widely used as a soft magnetic sheet material for wireless charging modules due to its characteristics, but it is difficult to meet the global trend to further reduce the thickness of the module due to its low saturation magnetic flux density. A nanocrystalline soft magnetic sheet of at least 1.5 Tesla is at an essential stage. In addition, since it is necessary to minimize the heat generated during wireless charging, it is necessary to minimize the eddy current loss and develop a material with high saturation magnetic flux density and permeability.

Currently, among the materials with high saturation magnetic flux density, typical nanocrystalline materials are Fe-Si-BP-Cu alloys and Fe-BC-Cu alloys, etc., but they have very low thermal stability and abnormal grain growth (abnormal grain growth). ) has a disadvantage in that the characteristics are deteriorated.

Recently, with the development of high-tech industries and high functionalization of electronic devices, the demand for nanocrystalline soft magnetic alloys with excellent magnetization characteristics is rapidly increasing. In particular, in the fields of wireless charging and high-performance inductors, not only excellent magnetic permeability and excellent core loss, but also a shielding function and an increase in charging speed during wireless charging are emerging as essential required characteristics. The currently used shielding and highly magnetized thin plate materials for modules of inductive magnetization wireless chargers have an amorphous or nanocrystalline structure, but the amorphous material has the disadvantage of low magnetic permeability and uses the existing Finemet alloy (Hidachi's nanocrystalline soft magnetic alloy brand name) The nanocrystalline soft magnetic material has a saturation magnetic flux density of about 1.2 Tesla, so higher magnetization properties are required.

The present inventors have disclosed a nanocrystalline soft magnetic alloy powder core in which calcium is added to an iron (Fe)-based alloy in Korean Patent Publication No. 10-2013-0073343. In the above patent, an amorphous alloy ribbon is prepared by adding calcium (Ca) to Fe-Si-B-Nb-Cu (at%) in an amount of 0.01 to 2 at%, and an amorphous alloy powder is formed by pulverizing the amorphous alloy ribbon, The classified powder and the binder are mixed, pressed to form a powder core, and a method for manufacturing the powder core is further heat-treated at 500 to 550° C. is disclosed. However, the soft magnetic alloy powder core has a saturation magnetic flux density of only about 1.2 Tesla, so that when used in a wireless charging module, the thickness of the module is thick and the performance is not good, so it is difficult to use it in a wireless charging module.

In addition, Japanese Patent No. 4623400 discloses a soft magnetic alloy thin band with a small air pocket size manufactured by a single roll method, and discloses Fe _{100 -xay- z} A _x M _a Si _y B _z (at%), have. However, although the alloy thin band has improved corrosion resistance and improved magnetic properties, it is difficult to achieve the saturation magnetic flux density required for a wireless charging module.

An object of the present invention is to provide an iron-based nanocrystalline soft magnetic alloy ribbon in which eddy current loss is minimized, saturation magnetic flux density and magnetic permeability are high, and nanocrystal growth is suppressed.

The above problem is a nanocrystalline soft magnetic alloy ribbon having a composition in which calcium (Ca) is added to an iron (Fe)-based alloy, silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium (Ca) 0.005 to 2.0 at%, and iron (Fe) characterized in that the remaining amount is achieved by a nanocrystalline soft magnetic alloy ribbon.

Preferably, the soft magnetic alloy ribbon may be for a wireless charging module.

Also preferably, the composition in which calcium (Ca) is added to the iron (Fe)-based alloy may further include 0.1 to 3.0 at% of zirconium (Zr).

Also preferably, the nanocrystalline soft magnetic alloy ribbon may have a saturation magnetic flux density of 1.5 Tesla or more.

In addition, the above tasks are silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium (Ca) 0.005 to 2.0 at%, and iron (Fe) Achieving by a method of manufacturing a nanocrystalline soft magnetic alloy ribbon for a wireless charging module, comprising the steps of manufacturing an alloy ribbon comprising a remaining amount, and heat-treating the alloy ribbon at a temperature of 440 to 480° C. for 5 to 60 minutes do.

In addition, the above tasks are silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium (Ca) 0.005 to 2.0 at%, and iron (Fe) Achieved by a method of manufacturing a nanocrystalline soft magnetic alloy ribbon for a wireless charging module, comprising the steps of manufacturing an alloy ribbon comprising a remaining amount, and heat-treating the alloy ribbon at a temperature of 500 to 550° C. for 5 to 60 minutes do.

The iron-based nanocrystalline soft magnetic alloy ribbon prepared according to the present invention has an amorphous structure and has fine nanocrystalline grains through crystallization heat treatment. Due to this, the soft magnetic alloy ribbon of the present invention has a high saturation magnetic flux density of 1.5 Tesla or more, so it is possible to reduce the thickness of the wireless charging module as well as to further reduce eddy current loss by the insulating effect of fine nanocrystal grains. It can also be used in the 10 MHz band. In addition, it is expected to greatly promote the widespread use and practical use of electromagnetic wave absorption and wireless efficiency enhancer sheets, and can be widely used in fields where soft magnetic ribbon cores are used, such as inductors of electronic devices and small transformers.

1 is Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at% ((Fe ₉₁ Si ₇ B ₂ wt%)) (FIG. 1a) and the nanocrystalline soft magnetic alloy of the present invention (Metglas 2605-S2 + 1 wt%) Cu, 0.03 wt% Ca) (FIG. 1b) is a photograph observed with a transmission electron microscope (TEM) of grain size after heat treatment at 540° C. for 1 hour.
2 is a transmission electron microscope (transmission electron microscope) of the nanocrystalline soft magnetic alloy ribbon (Metglas 2605-S2 + 1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) of the present invention after heat treatment at 540 ° C. for 1 hour. TEM) was observed.
Figure 3 is Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at% ((Fe ₉₁ Si ₇ B ₂ wt%)) (a) and the nanocrystalline soft magnetic alloy of the present invention (Metglas 2605-S2 + 1 wt% Cu) , 2.48 wt% Zr, 0.19 wt% Ca)(b) is a photograph of a specimen subjected to heat treatment at 540°C for 30 minutes, observed with a transmission electron microscope (TEM).
FIG. 4 is a photograph of the transmission electron microscope (TEM) microstructure of FIG. 3(b) taken again as a dark field image.
5 is a Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at% ((Fe ₉₁ Si ₇ B ₂ wt%)) alloy ribbon (a) and the alloy ribbon of the present invention Metglas 2605-S2 + 1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) (b) is a TEM diffraction pattern (Selected Area Diffration Pattern: SADP) was taken.
6 is a photograph (a) observing the microstructure of a separately prepared alloy ribbon (Metglas 2605-S2 + 0.9 wt% Cu, 0.03 wt% Ca) by TEM, and EELS mapping to understand the distribution of Ca elements. ) is a picture (b).
7 is a photograph (a) observing the microstructure of the alloy ribbon (Metglas 2605-S2 + 1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) alloy ribbon of the present invention by TEM (a) and the distribution of Zr element It is a picture (b) of EELS mapping to understand.

All technical terms used in the present invention, unless otherwise defined, have the following definitions and are consistent with the meanings commonly understood by one of ordinary skill in the art of the present invention. In addition, although preferred methods and samples are described herein, similar or equivalent ones are also included in the scope of the present invention.

The term "about" refers to 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, means an amount, level, value, number, frequency, percentage, dimension, size, amount, weight or length varying by 4, 3, 2 or 1%.

Throughout this specification, unless the context requires otherwise, the terms "comprises" and "comprising" include the steps or elements presented, or groups of steps or elements, but any other step or element, or It is to be understood that a step or group of elements is not excluded.

The present invention provides a nanocrystalline soft magnetic alloy ribbon (ribbon: Thin Strip) for a wireless charging module having a composition in which calcium (Ca) is added to an iron (Fe)-based alloy and a method for manufacturing the same. Specifically, the composition in which calcium (Ca) is added to the iron (Fe)-based alloy is 1 to 15 at% of silicon (Si), 5 to 15 at% of boron (B), 0.1 to 3 at% of copper (Cu), and calcium (Ca) 0.005-2.0 at% and iron (Fe) are included as the balance.

In order to solve the problems of the Fe-Si-BP-Cu-based alloy and the Fe-BC-Cu-based alloy, which are typical nanocrystal materials having high saturation magnetic flux density, the present invention has no solid solubility with Fe and does not form a compound. It is characterized in that Ca and Cu elements (Immiscible Elements) are added. Cu atoms gather to form a cluster, which serves as a uniform nucleation site for α-Fe crystals, and Ca atoms are distributed at grain boundaries to suppress grain growth and significantly increase resistivity.

According to the present invention, by adding a small amount of zirconium (Zr), it is possible to significantly reduce the size of the crystal grains. Preferably, Zr is preferably contained in an amount of 0.1 to 3.0 at%. When Zr is added together with Ca, the saturation magnetic flux density is improved to exhibit better magnetization properties.

According to an embodiment of the present invention, the manufacturing method of the nanocrystalline soft magnetic alloy ribbon is silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium (Ca) 0.005 to 2.0 at% and preparing an alloy ribbon containing iron (Fe) as the remaining amount (S11), and the alloy ribbon at a temperature of 440 to 480 ° C. for 5 to 60 minutes, more preferably 10 It includes a step (S12) of heat treatment for ~20 minutes.

More specifically, the step S11 includes adding Ca and Cu to the Fe-Si-B-based amorphous alloy and manufacturing an amorphous alloy ribbon by a melt spinning process, which is a type of rapid solidification method. Preferably, the Fe-Si-B-based amorphous alloy may be Fe ₇₈ Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2).

In the present invention, it is characterized in that 0.1 to 3 at% of Cu and 0.005 to 2.0 at% of Ca are added to the Fe-Si-B-based amorphous alloy. Through this, Ca located at the grain boundary acts as an insulator and plays the role of a power charger enhancer that significantly increases the wireless charging speed while suppressing heat generation much more than the segment-shaped amorphous sheet. That is, the Fe-Si-B-based alloy can be made of fine nanocrystals of 10 nm or less by distributing Ca at the grain boundary to suppress grain growth. In addition, with the addition of a small amount of Ca of 0.005 to 2.0 at%, the magnetic permeability is maintained and the resistivity measurement is increased by about 4 times, and CaO is formed on the surface to increase the insulation effect between the ribbons, and the core loss can be greatly reduced. It can be used as an excellent electromagnetic wave absorption and enhancer for wireless charging.

The alloy ribbon of the present invention is characterized in that the content of iron is increased without including niobium (Nb). Niobium (Nb) is an expensive metal, and in general, about 3 at% must be added to suppress grain growth. However, when Nb is added, it is difficult to increase the saturation magnetic flux density because the Fe content is relatively decreased. In the present invention, by adding Ca, it is possible to obtain fine nanocrystals by suppressing the growth of nanocrystals without using Nb.

In addition, the present invention is made of an alloy ribbon (ribbon: Thin Strip) rather than powder, so that it has superior initial permeability than a powder core and serves to enhance the shielding/absorption and charging efficiency of the wireless charging module. It is possible to further reduce the thickness of the soft magnetic sheet of the module by increasing the saturation magnetic flux density. Thereby, practical use and replacement of existing materials are possible.

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited by these Examples.

Experimental example One

The change in the saturation magnetic flux density of the alloy ribbon according to the heat treatment temperature and time was measured. _{Fe 78} Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by the melt spinning process An amorphous alloy ribbon was prepared by adding 1 wt% or 0.4 wt% of Cu, 0.03 wt% or 0.04 wt% of Ca, respectively. The alloy ribbon was heated at 440°C, 460°C, and 480°C for 10 minutes and 20 minutes, respectively, and the saturation magnetic flux density (Tesla) was measured (measurement conditions - Fequency: 50Hz, Hm: 800A/m). The results are shown in Table 1.

Example (wt%) at the heat treatment temperature (℃)
Saturated magnetic flux density according to
(Tesla) heat treatment time
(min.) control
[ Fe ₇₈ Si ₉ B ₁₃ ] 440 460 480 Fe- Si -B- 1Cu - 0.03Ca 1.56 1.53 1.59 10 Heat treatment conditions 430°C, 37 minutes Fe- Si -B- 0.4Cu - 0.04Ca 1.57 1.60 1.58 1.61 Fe- Si -B- 1Cu - 0.03Ca 1.56 1.58 1.58 20 Fe- Si -B- 0.4Cu - 0.04Ca 1.58 1.58 1.58

Referring to Table 1, as the content of Ca and Cu increased, the saturation magnetic flux density was almost the same or decreased slightly.

Experimental example 2

The change of coercive force of alloy ribbon according to heat treatment temperature and time was measured. _{Fe 78} Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by the melt spinning process Cu 1 wt%, 0.4 wt%, Ca 0.03 wt%, and 0.04 wt% were respectively added to prepare an amorphous alloy ribbon. The alloy ribbon was heated at 440° C., 460° C., and 480° C. for 10 minutes and 20 minutes, respectively, and the coercive force (A/m) was measured (measurement conditions - Fequency: 50 Hz, Hm: 800 A/m). The results are shown in Table 2.

Example (wt%) at the heat treatment temperature (℃)
coercive force value (A/m) heat treatment time
(min.) control
[ Fe ₇₈ Si ₉ B ₁₃ ] 440 460 480 Fe- Si -B- 1Cu - 0.03Ca 5.3 15.68 75.8 10 Heat treatment conditions 430°C, 37 minutes Fe- Si -B- 0.4Cu - 0.04Ca 5.01 8.74 205.8 9.96 [A/m] Fe- Si -B- 1Cu - 0.03Ca 15.83 75.49 72.14 20 Fe- Si -B- 0.4Cu - 0.04Ca 7.16 119 186.7

Referring to Table 2, as the Ca content of the prepared alloy ribbon increased, the coercive force of the ribbon was greatly reduced by about 50% or more. The Fe-Si-B amorphous ribbon alloy has a coercive force of 9.96 A/m, but when the Ca-added alloy ribbon was heat treated at 440°C for 10 minutes, the ribbon core containing 0.03 wt% Ca had a coercive force of 5.3 A/m and 0.04. The alloy ribbon containing wt% showed a coercive force of 5.01 A/m. In the Fe-Si-B-based alloy, it can be seen that the coercive force is reduced by the addition of Ca and the grain growth is effectively suppressed to form nanocrystals. In addition, even when the amount of Cu added is lowered from 1 wt% to 0.4 wt%, it can be expected that Ca will play a role as a heteronuclear site. However, in this case, since the crystal refinement effect is small, it seems that the addition amount of Ca or Cu should be further increased.

Experimental example 3

The change in the core loss of the alloy ribbon according to the heat treatment temperature and time was measured. _{Fe 78} Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by the melt spinning process Cu 1 wt%, 0.4 wt%, Ca 0.03 wt%, and 0.04 wt% were respectively added to prepare an amorphous alloy ribbon. The alloy ribbon was heated at 440° C., 460° C., and 480° C. for 10 minutes and 20 minutes, respectively, and the core loss (mW/cm) was measured (measurement conditions - 0.1 Tesla, 50 kHz). The results are shown in Table 3.

Example (wt%) Core loss according to heat treatment temperature (℃)
(mW/cm) heat treatment
time (min) control
[ Fe ₇₈ Si ₉ B ₁₃ ] 440 460
Fe- Si -B- 1Cu - 0.03Ca
151.67 - 10 Heat treatment conditions 430°C, 37 minutes
Fe- Si -B- 0.4Cu - 0.04Ca 119.98 44.41 175.05

Referring to Table 3, as the Ca content of the Fe-Si-B-Cu-Ca alloy ribbon increased, the core loss significantly decreased by more than 80%. This can be interpreted as a decrease in the amount of Cu as Cu interacts with Ca when the amount of Ca is increased. The core loss was 175.05 mW/cm for the amorphous ribbon. However, when the Fe-Si-B-0.4Cu-0.04Ca nanocrystal alloy ribbon was heat treated at 460° C. for 10 minutes, the ribbon core loss was 44.41 mW/cm.

Experimental example 4

In order to confirm the effect of inhibiting nanocrystal growth in the soft magnetic alloy ribbon of the present invention according to the addition of Ca, a heat treatment experiment was performed. Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at%) (Fe ₉₁ Si ₇ B ₂ wt%) (FIG. 1a) and the nanocrystalline soft magnetic alloy of the present invention (Metglas 2605-S2 + 1 wt% Cu, 0.03 wt. % Ca) (FIG. 1b) was prepared as an alloy ribbon, and the grain size after heat treatment at 540° C. for 1 hour was photographed with a transmission electron microscope (TEM), and is shown in FIG. 1 .

When the heat treatment temperature is low, crystals are only partially dispersed in the amorphous substrate. Therefore, in order to more accurately confirm the crystallization fraction according to the addition of Ca, the heat treatment temperature was set to 540°C.

1a, when Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at% (Fe ₉₁ Si ₇ B ₂ wt%)) alloy was heat treated at 540° C. for 1 hour, the crystal grains having a size of about 100 nm or more were formed. It is confirmed that the number of crystals nucleated in the amorphous matrix is very limited. Partially, abnormal grain growth occurs and many very coarse crystals are observed. However, referring to FIG. 1B , it was confirmed that when Ca was added, Ca was not dissolved in the crystal during crystal growth but was pushed into the amorphous region and distributed around the crystal grains. Due to this behavior of Ca, the effect of inhibiting the growth of crystals and refining each crystal can be confirmed.

Experimental Example 5

In order to confirm the effect of inhibiting nanocrystal growth in the soft magnetic alloy ribbon according to the addition of Ca and Zr, a heat treatment experiment was performed. Nanocrystalline soft magnetic alloy of the present invention (Metglas 2605-S2 (Fe ₉₁ Si ₇ B ₂ wt% (Fe ₇₈ Si ₉ B ₁₃ at%)) + 1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) It was prepared with an alloy ribbon, and the grain size after heat treatment at 540° C. for 1 hour was photographed with a transmission electron microscope (TEM), and is shown in FIG. 2 .

For the preparation of rapid solidification ribbon, in order to facilitate the addition of Ca, the atmospheric pressure in the melting furnace chamber is ^{lowered to 1x10 -4} Torr, and Ar is injected back to atmospheric pressure to prepare an ingot, and then melt-spinning is used. Fe-based ribbons were prepared. During casting, the molten metal was maintained at a temperature of about 1,250°C, the distance between the spray nozzle and the wheel was 150 μm, and the wheel rotation speed was adjusted between 3000 rpm to produce a soft magnetic alloy ribbon with a thickness of 4 mm and a width of about 20 μm. did.

Referring to FIG. 2 , when Zr was added, the grain size was 46 nm, indicating that the size of the crystal was significantly reduced. From this, it can be seen that the small addition of Zr has a great effect in suppressing grain growth.

Experimental Example 6

Fe-Si-B (Fe ₉₁ Si ₇ B ₂ wt%) Cu, Zr, and Ca were simultaneously added (1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) to an amorphous alloy ribbon and heat treated at 540°C for 30 minutes One specimen was observed by TEM, and is shown in FIG. 3 . The average grain size of the Fe-Si-B-Cu-Zr-Ca (1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) alloy ribbon of FIG. As about 15 nm, Fe-Si-B, Fe-Si-B-Cu-Zr (0.98 wt % Cu, 0.12 wt % Zr), Fe-Si-B-Cu-Ca (0.4 wt % Cu, 0.04 wt % Ca ) was significantly reduced than the grain size of the alloy ribbon.

FIG. 4 is a dark field image of the TEM microstructure of FIG. 3(b) again, and as an example of measuring the exact size of crystals diffracted in the same direction, the measurement result showed a crystal of 13.85 mn. That is, based on the analysis based on these results, grain growth is greatly suppressed by the addition of 0.19% Ca and 2.48% Zr, so that uniform distribution of nanocrystals with a size of 10 to 15 nm, which is essential in advanced soft magnetic materials, can be realized appeared to be Accordingly, it is expected that the Fe-Si-B-Cu-Zr-Ca-based alloy ribbon has a significantly increased magnetic permeability and significantly increased iron loss and coercive force compared to conventional materials.

On the other hand, Figure 5 is a Fe-Si-B (Fe ₉₁ Si ₇ B ₂ wt%) alloy ribbon (a) and Fe-Si-B-Cu-Zr-Ca (1 wt% Cu, 2.48 wt% Zr, 0.19 wt% % Ca) A diffraction pattern (Selected Area Diffration Pattern: SADP) of the alloy ribbon (b) was taken by TEM. 5(a) is an alloy ribbon in which Fe-Si-B amorphous is heat treated for 30 minutes, and it can be seen that many α-Fe crystals are distributed in the amorphous matrix of grain boundaries. 5 (b) is a diffraction pattern of the Fe-Si-B-Cu-Zr-Ca alloy ribbon, in which α-Fe crystals Fe(Si) crystals were finely formed by the cluster formation of Cu and addition of Cu and Zr, It can be seen that the fraction of the amorphous phase is greatly reduced. Here, the unit of 10 1/nm represents the length of the reciprocal lattice, and when compared with the reciprocal of the interplanar distance of the α-Fe crystal using Rd = λL (camers constant of TEM), which is a common analytic formula of TEM diffraction patterns, it is accurate will match That is, since the lattice constant of Fe is 0.286 nm (2.86 Å), the unit of the value obtained by taking the reciprocal of the interplanar distance is 1/nm.

In addition, it can be observed that the spacing of the ring pattern is the smallest and the number of diffraction spots is the largest. These results prove that the addition of Cu, Zr, and Ca greatly contributed to the formation of nanocrystals. give.

Experimental Example 7

An alloy ribbon with 0.9 wt% Cu and 0.03 wt% Ca added to Fe ₉₁ Si ₇ B ₂ wt% (Fe ₇₈ Si ₉ B ₁₃ at%) was separately prepared, and the microstructure was observed by TEM and the distribution of Ca element was identified. In order to do this, EELS mapping was performed and shown in FIG. 6 . 6(a) is a microstructure photograph of an alloy ribbon in which crystal grains are grown large at a high temperature of 560° C. for 1 hour, and FIG. 6(b) is a photograph of a Ca element at that location mapped with EELS. It is analyzed that Ca is mainly distributed at grain boundaries and very effectively inhibits grain growth.

On the other hand, Figure 7 is a photograph of EELS mapping to observe the microstructure of the Fe-Si-B-1.0Cu-2,48Zr-0.19Ca (wt%) alloy ribbon by TEM and to understand the distribution of Zr element. When the Zr element is additionally added, the Zr element is mainly distributed at the grain boundary, but it is also distributed within the grain. Since Ca and Zr distributed at the grain boundary do not mix at all and do not form a solid solution or compound, the distribution positions are different. is judged Zr has been shown to play a role in stabilizing the grain boundaries of the amorphous structure surrounding the crystal, thereby greatly inhibiting crystal growth and reducing eddy current loss. Accordingly, it is interpreted that the size of the nanocrystals can be easily controlled with only a small amount of Cu, Zr and Ca elements in the Fe-based soft magnetic alloy, and the effect of greatly reducing the eddy current loss is expected.

Claims (6)

A nanocrystalline soft magnetic alloy ribbon having a composition in which calcium (Ca) is added to an iron (Fe)-based alloy, silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium (Ca) 0.005 to 2.0 at% and iron (Fe) characterized in that it contains the remaining amount, the nanocrystalline soft magnetic alloy ribbon. The nanocrystalline soft magnetic alloy ribbon according to claim 1, wherein the soft magnetic alloy ribbon is for a wireless charging module. The nanocrystalline soft magnetic alloy ribbon of claim 1, wherein the iron (Fe)-based alloy has a composition in which calcium (Ca) is added further comprises 0.1 to 3.0 at% of zirconium (Zr). delete An alloy containing 1 to 15 at% of silicon (Si), 5 to 15 at% of boron (B), 0.1 to 3 at% of copper (Cu), 0.005 to 2.0 at% of calcium (Ca) and iron (Fe) in the balance. Manufacturing method of a nanocrystalline soft magnetic alloy ribbon for a wireless charging module comprising the step of manufacturing a ribbon, and heat-treating the alloy ribbon for 5 to 60 minutes at a temperature of 440 to 480 ℃. An alloy containing 1 to 15 at% of silicon (Si), 5 to 15 at% of boron (B), 0.1 to 3 at% of copper (Cu), 0.005 to 2.0 at% of calcium (Ca) and iron (Fe) in the balance. Manufacturing method of a nanocrystalline soft magnetic alloy ribbon for a wireless charging module comprising the step of manufacturing a ribbon, and heat-treating the alloy ribbon for 5 to 60 minutes at a temperature of 500 to 550 ℃.

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