KR20200132738A - Fe BASED NANO-STRUCTURED SOFT MAGNETIC ALLOY RIBBON AND METHOD FOR PREPARING THE SAME - Google Patents

Abstract

The present invention relates to an iron (Fe)-based soft-magnetic alloy ribbon with higher saturation magnetic flux density than a conventional nano-grain soft-magnetic alloy and excellent magnetic permeability and core loss properties at a high frequency and a manufacturing method thereof and, more specifically, to a Fe-based nano-grain soft-magnetic alloy ribbon for a wireless charging module and a manufacturing method thereof. Preferably, the nano-grain soft-magnetic alloy ribbon has a composition in which calcium (Ca) is added to an iron (Fe)-based alloy and specifically comprises 1-15 atom% of silicon (Si), 5-15 atom% of boron (B), 0.1-3 atom% of copper (Cu), 0.005-2 atom% of calcium (Ca), and the remainder consisting of iron (Fe).

Description

Iron-based nanocrystal grain soft magnetic alloy ribbon and its manufacturing method {Fe BASED NANO-STRUCTURED SOFT MAGNETIC ALLOY RIBBON AND METHOD FOR PREPARING THE SAME}

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

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

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

Fe-Si-BP-Cu-based alloys and Fe-BC-Cu-based alloys are the most widely known materials among materials with high saturation magnetic flux density, but their thermal stability is very low and Abnormal Grain Growth There is a disadvantage of deteriorating the properties by ).

Recently, the demand for nanocrystalline soft magnetic alloys with excellent magnetization characteristics is increasing rapidly with the development of high-tech industries and high functionalization of electronic devices. In particular, in the fields of wireless charging and high-performance inductors, not only has 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 characteristics required. The shielding and high-magnetization thin plate for modules of inductively magnetized wireless chargers currently in use have amorphous or nanocrystalline structure, but amorphous materials have a low permeability and use the existing Finemet alloy (a brand name of Hitachi's nanocrystalline soft magnetic alloy). The nanocrystalline soft magnetic material has a saturation magnetic flux density of about 1.2 Tesla, and higher magnetization characteristics 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) in an amount of 0.01 to 2 at% to Fe-Si-B-Nb-Cu (at%), and the amorphous alloy ribbon is pulverized to form an amorphous alloy powder, A method of preparing a powder core by classifying it, mixing the classified powder and a binder, forming a powder core by pressing, and heat-treating the powder core 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 when used in a wireless charging module, the thickness of the module becomes thick and its performance is poor, making it difficult to use it in a wireless charging module.

In addition, Japanese Patent No. 4623400 discloses a soft magnetic alloy thin strip having a small air pocket size manufactured by the single roll method, and discloses Fe _{100 -xay- z} A _x M _a Si _y B _z (at%). have. However, the alloy thin strip has improved corrosion resistance and improved magnetic properties, but it is difficult to achieve the saturation magnetic flux density required in 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 permeability are high, and growth of nanocrystals is suppressed in order to solve the problems of the prior art.

The above-described task 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%, characterized by containing iron (Fe) in the balance, 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-described 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 step of preparing an alloy ribbon containing the 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-described 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 step of preparing an alloy ribbon containing the 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. For this reason, the soft magnetic alloy ribbon of the present invention has a high saturation magnetic flux density of 1.5 Tesla or more, so that not only can the thickness of the wireless charging module be reduced, but also the eddy current loss can be further reduced by the insulating effect of the fine nanocrystal grains. It can also be used in the 10 MHz band. In addition, it is expected to greatly promote 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 and small transformers of electronic devices.

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 of observing the grain size after heat treatment at 540°C for 1 hour with a transmission electron microscope (TEM).
2 is a transmission electron microscope showing the grain size 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).
3 is a 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 observed with a transmission electron microscope (TEM) of a specimen heat-treated at 540° C. for 30 minutes.
4 is a photograph of a transmission electron microscope (TEM) microstructure of FIG. 3(b) taken again as a dark field image.
Figure 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 A diffraction pattern (Selected Area Diffration Pattern: SADP) was photographed using wt% Zr, 0.19 wt% Ca)(b) by TEM.
6 is a photograph (a) of a microstructure of a separately manufactured alloy ribbon (Metglas 2605-S2 + 0.9 wt% Cu, 0.03 wt% Ca) by TEM, and EELS mapping in order to understand the distribution of Ca elements. ) This is a picture (b).
7 is a photograph (a) of observing the microstructure of the alloy ribbon of the present invention (Metglas 2605-S2 + 1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) by TEM, and the distribution of Zr elements. This is the EELS-mapped picture (b) to understand.

All technical terms used in the present invention, unless otherwise defined, have the following definitions and correspond to the meanings as commonly understood by one of ordinary skill in the relevant fields of the present invention. In addition, although preferred methods or samples are described in the present specification, those similar or equivalent are included in the scope of the present invention.

The term “about” refers to 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, or 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, or relative to a reference amount, level, value, number, frequency, percentage, dimension, size, amount, weight or length. It 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 otherwise required by the context, the terms “comprise” and “comprising” include the steps or components presented, or groups of steps or components, but any other step or component, or It is to be understood that a step or group of components 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 of manufacturing the same. Specifically, the composition in which calcium (Ca) is added to the iron (Fe)-based alloy is silicon (Si) 1 to 15 at%, boron (B) 5 to 15 at%, copper (Cu) 0.1 to 3 at%, calcium. (Ca) 0.005~2.0 at% and iron (Fe) are included in the balance.

In order to solve the problems of the conventional Fe-Si-BP-Cu-based alloy and Fe-BC-Cu-based alloy, which are typical nanocrystalline 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 clusters, which act as a homogeneous nucleation site of α-Fe crystals, and Ca atoms are distributed in grain boundaries to inhibit grain growth and increase specific resistance.

According to the present invention, by adding a small amount of zirconium (Zr), the size of crystal grains can be significantly reduced. 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 show more excellent magnetization characteristics.

According to an embodiment of the present invention, a method of manufacturing a 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) manufacturing an alloy ribbon containing 0.005 to 2.0 at% and iron (Fe) in the balance (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 an Fe-Si-B-based amorphous alloy, and preparing an amorphous alloy ribbon by a melt spinning process, which is a kind 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, the Fe-Si-B-based amorphous alloy is characterized by adding 0.1 to 3 at% of Cu and 0.005 to 2.0 at% of Ca. Through this, Ca located at the grain boundary acts as an insulator, and it plays the role of a Power Charger Enhancer that significantly increases the wireless charging speed while suppressing heat generation much more than that of a segmented amorphous sheet. That is, by distributing Ca to grain boundaries to suppress grain growth, the Fe-Si-B-based alloy can be made of fine nanocrystals of 10 nm or less. In addition, even with the addition of a trace amount of Ca of 0.005 to 2.0 at%, the permeability is maintained and the resistivity measurement increases 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 it does not contain niobium (Nb) and has an increased iron content. Niobium (Nb) is an expensive metal, and it is generally necessary to add about 3 at% to suppress grain growth. However, when Nb is added, the content of Fe is relatively decreased, making it difficult to increase the saturation magnetic flux density. In the present invention, by adding Ca, it is possible to obtain fine nanocrystals by suppressing the growth of nanocrystal grains without using Nb.

In addition, in the present invention, by manufacturing a soft magnetic alloy with an alloy ribbon (Thin Strip) instead of a powder, the superpermeability is superior to that of the powder core, and the shielding/absorption and charging efficiency of the wireless charging module are improved (enhancer). In addition, the thickness of the soft magnetic sheet of the module can be further reduced by increasing the saturation magnetic flux density. Thereby, it is possible to commercialize and replace existing materials.

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. To Fe ₇₈ Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by a melt spinning process 1 wt% or 0.4 wt% of Cu, 0.03 wt% or 0.04 wt% of Ca were each 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 saturation magnetic flux density (Tesla) was measured (Measurement condition-Fequency: 50Hz, Hm: 800A/m). The results are shown in Table 1.

Example (wt%) At the heat treatment temperature (℃)
Saturation 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℃, 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

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

Experimental example 2

The change of the coercive force of the alloy ribbon according to the heat treatment temperature and time was measured. To Fe ₇₈ Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by a melt spinning process 1 wt% of Cu, 0.4 wt%, 0.03 wt% of Ca, and 0.04 wt% of Ca were each 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: 50Hz, Hm: 800A/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℃, 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 coercivity of the ribbon decreased by about 50% or more. Fe-Si-B amorphous ribbon alloy has a coercive force of 9.96 A/m, but when the alloy ribbon added with Ca was heat treated at 440°C for 10 minutes, the ribbon core containing 0.03 wt% Ca was 5.3 A/m, 0.04 The alloy ribbon containing wt% showed a coercive force of 5.01 A/m. It can be seen that the Fe-Si-B-based alloy decreases coercivity by the addition of Ca and effectively inhibits grain growth 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 heterogeneous nucleation site. However, in this case, since the crystallization effect is small, it seems that the addition amount of Ca or Cu should be further increased.

Experimental example 3

The change in core loss of the alloy ribbon according to the heat treatment temperature and time was measured. To Fe ₇₈ Si ₉ B ₁₃ (at%) (Fe ₉₁ Si ₇ B ₂ wt%, Metglas 2605-S2) by a melt spinning process 1 wt% of Cu, 0.4 wt%, 0.03 wt% of Ca, and 0.04 wt% of Ca were each added to prepare an amorphous alloy ribbon. The alloy ribbon was heated to 440°C, 460°C, and 480°C for 10 minutes and 20 minutes, respectively, and the core loss (mW/cm) was measured (measurement condition-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℃, 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 reacts with Ca when the amount of Ca added is increased. The core loss was 175.05 mW/cm for the amorphous ribbon. However, when the Fe-Si-B-0.4Cu-0.04Ca nanocrystalline 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 the growth of nanocrystals in the soft magnetic alloy ribbon of the present invention according to the addition of Ca, a heat treatment experiment was conducted. 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.

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

Referring to Figure 1a, when the Metglas 2605-S2 (Fe ₇₈ Si ₉ B ₁₃ at% (Fe ₉₁ Si ₇ B ₂ wt%)) alloy is heat-treated at 540° C. for 1 hour, it is formed of crystal grains having a size of about 100 nm or more. It can be confirmed, and it is understood that the number of nucleated crystals in the amorphous base is very limited. Partly because of abnormal grian growth, 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 to the amorphous region and distributed around the crystal grains. Due to this behavior of Ca, it is possible to confirm the effect of suppressing the growth of crystals and minimizing each crystal.

Experimental Example 5

In order to confirm the effect of inhibiting the growth of nanocrystals in the soft magnetic alloy ribbon according to the addition of Ca and Zr, a heat treatment experiment was performed. The 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) The crystal grain size after it was prepared with an alloy ribbon and heat-treated at 540° C. for 1 hour was photographed with a transmission electron microscope (TEM), and is shown in FIG. 2.

In order to facilitate the addition of Ca, the pressure in the furnace chamber is lowered to 1x10 ^-4 Torr, and Ar is injected again to atmospheric pressure to prepare an ingot, and then melt-spinning is used. An Fe-based ribbon was produced. During casting, the molten metal was maintained at a temperature of about 1,250℃, and the spacing 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. I did.

2, when Zr was added, the crystal grain size was 46 nm, indicating that the size of the crystal was significantly reduced. Through this, it can be seen that the addition of a small amount of Zr has a great effect in inhibiting grain growth.

Experimental Example 6

Fe-Si-B (Fe ₉₁ Si ₇ B ₂ wt%) added Cu, Zr, and Ca simultaneously to the amorphous alloy ribbon (1 wt% Cu, 2.48 wt% Zr, 0.19 wt% Ca) and heat treated at 540°C for 30 minutes One specimen was observed by TEM and 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. 3(b) in which Zr and Ca are added at the same time is about 13 ~ 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 ) The grain size of the alloy ribbon decreased significantly

4 is a photograph of the TEM microstructure of FIG. 3(b) again as a dark field image, as an example of measuring the exact size of crystals diffracted in the same direction, and the measurement result was a crystal of 13.85 mn. In other words, if analyzed based on these results, grain growth was greatly suppressed by the addition of 0.19% Ca and 2.48% Zr, thereby realizing a uniform distribution of nanocrystals with a size of 10 to 15 nm, which is essential for advanced soft magnetic materials. Appeared to be. Accordingly, it is expected that the Fe-Si-B-Cu-Zr-Ca-based alloy ribbon will have a large increase in permeability, and the iron loss and coercivity will increase significantly 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) Alloy ribbon (b) was photographed with a TEM (Selected Area Diffration Pattern: SADP). 5(a) is an alloy ribbon obtained by heat treatment of Fe-Si-B amorphous for 30 minutes, and it can be seen that many α-Fe crystals are distributed in an amorphous matrix of grain boundaries. 5(b) is a diffraction pattern of an Fe-Si-B-Cu-Zr-Ca alloy ribbon, in which α-Fe crystals Fe(Si) crystals were finely formed by 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 inverse lattice, and when compared with the reciprocal of the interplanar distance of the α-Fe crystal by using Rd=λL (camers constant of TEM), which is an analytical equation that is a common definition of the TEM diffraction pattern, 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 finest 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 elements was identified. In order to do so, it is shown in FIG. 6 by EELS mapping. FIG. 6(a) is a microstructure picture of an alloy ribbon in which crystal grains are grown at a high temperature of 560° C. for 1 hour, and FIG. 6(b) is a picture of a Ca element at that location mapped to EELS. It is analyzed that Ca is mainly distributed at grain boundaries and very effectively inhibits grain growth.

Meanwhile, FIG. 7 is a photograph of EELS mapping in order to observe the microstructure of the Fe-Si-B-1.0Cu-2,48Zr-0.19Ca (wt%) alloy ribbon by TEM and to determine the distribution of Zr elements. When the Zr element is additionally added, the Zr element is mainly distributed in the grain boundaries, but it is also distributed in the grains, but Ca and Zr distributed in the grain boundaries do not mix at all and do not form a solid solution or compound, so the distribution positions are different. Is judged. Zr was found to play a role in stabilizing the grain boundaries of the amorphous structure surrounding the crystal, thus greatly suppressing crystal growth and at the same time playing an insulating role to reduce eddy current loss. Accordingly, it is interpreted that in the Fe-based soft magnetic alloy, not only can the size of the nanocrystal can be easily controlled by adding a small amount of Cu, Zr and Ca elements, but also an effect of greatly reducing eddy current loss can be expected.

Claims (6)

As a nanocrystalline soft magnetic alloy ribbon with a composition in which calcium (Ca) is added to an iron (Fe) 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 a balance, nanocrystalline soft magnetic alloy ribbon. The nanocrystalline grain 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 according to claim 1, wherein the composition in which calcium (Ca) is added to the iron (Fe)-based alloy further comprises 0.1 to 3.0 at% of zirconium (Zr). The nanocrystalline soft magnetic alloy ribbon according to any one of claims 1 to 3, wherein the nanocrystalline soft magnetic alloy ribbon has a saturation magnetic flux density of 1.5 Tesla or more. Alloy containing silicon (Si) 1~15 at%, boron (B) 5~15 at%, copper (Cu) 0.1~3 at%, calcium (Ca) 0.005~2.0 at%, and iron (Fe) in balance A method of manufacturing a nanocrystalline soft magnetic alloy ribbon for a wireless charging module comprising the step of preparing a ribbon, and heat-treating the alloy ribbon at a temperature of 440 to 480°C for 5 to 60 minutes. Alloy containing silicon (Si) 1~15 at%, boron (B) 5~15 at%, copper (Cu) 0.1~3 at%, calcium (Ca) 0.005~2.0 at%, and iron (Fe) in balance A method of manufacturing a nanocrystalline soft magnetic alloy ribbon for a wireless charging module comprising the step of preparing a ribbon, and heat-treating the alloy ribbon at a temperature of 500 to 550°C for 5 to 60 minutes.

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