A Fe-Co-Al soft magnetic material, its preparation method and application

Abstract

This invention relates to the field of soft magnetic materials technology, and in particular to a Fe-Co-Al soft magnetic material, its preparation method, and its applications. The material is prepared from Fe, Co, and Al as raw materials, weighed according to an atomic ratio of Fe:Co:Al = 3:1:1, and then processed through melting, rapid cooling, and heat treatment to obtain a soft magnetic material with the chemical formula Fe₃CoAl. The resulting material has a fully ordered cubic crystal structure of type DO₃. At room temperature, it exhibits a saturation magnetization of 162 emu / g, a coercivity of approximately 28.5 Oe, and a steep initial magnetization curve, demonstrating excellent magnetization sensitivity and rapid response even under weak magnetic fields. The Fe₃CoAl soft magnetic material of this invention significantly improves permeability and reduces coercivity through the introduction of Co, and its preparation process is simple, has a short cycle time, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic materials technology, and in particular to an Fe-Co-Al soft magnetic material, its preparation method, and its applications. Background Technology

[0002] Soft magnetic materials, as the "heart" of power electronic equipment, are widely used in key components such as transformers, inductors, filters, and sensors. Their performance directly determines the energy efficiency, power density, and operational stability of the equipment. With the rapid development of new energy vehicles, 5G communications, and smart grids, the industry has put forward the core requirements of "three highs and two lows" for soft magnetic materials: high saturation magnetization (Bs), high permeability (μ), high Curie temperature (Tc), and low coercivity (Hc) and low high-frequency loss. At the same time, the materials are required to have the characteristics of low cost and easy large-scale preparation to adapt to the development trend of equipment miniaturization and high frequency (above 20kHz).

[0003] Among numerous soft magnetic materials, Fe-Al alloys have attracted significant attention due to their unique resource and performance advantages. Aluminum (8.23% of the Earth's crust) and iron (5.63% of the Earth's crust) are both abundant, low-cost elements. Compared to expensive soft magnetic materials such as permalloy (approximately US$30,000 / ton) and nickel (approximately US$20,000 / ton) and cobalt-based amorphous materials, Fe-Al materials can reduce raw material costs by more than 60%, and have no heavy metal pollution risk, exhibiting excellent environmental compatibility. Furthermore, the intermetallic compounds formed by Al and Fe possess good mechanical properties and thermal stability. Through compositional control and process optimization, a balance between soft magnetic properties and cost can be achieved, making them a potential alternative to traditional high-cost materials.

[0004] Fe3Al, as an intermetallic compound with a high Fe content (Fe:Al=3:1) in the Fe-Al system, has been proven to possess typical soft magnetic properties in recent years, becoming a research hotspot in this field. Existing research shows that Fe3Al compounds have a DO3-type cubic crystal structure, in which Fe atoms form a densely packed magnetic sublattice, generating spontaneous magnetization through 3d electron spin coupling. The saturation magnetization of as-cast Fe3Al is 144 emu / g, and the coercivity is 52.1 Oe. A rapid cooling process (30 m / s) can reduce the coercivity to 35.5 Oe and increase the saturation magnetization to 149 emu / g; further annealing at 450℃ for 1 h can achieve a saturation magnetization of 171 emu / g, but the coercivity recovers to 39.4 Oe. It is evident that although Fe3Al possesses certain potential for soft magnetic properties, its coercivity remains consistently high (above 35 Oe) and its magnetic field sensitivity is also low, limiting its application in high-frequency, low-loss scenarios.

[0005] Traditional processes, centered on argon-arc melting, require melting raw materials into ingots at high temperatures, followed by a lengthy annealing process (typically 24-48 hours) to eliminate component segregation and promote the precipitation of ordered phases. This entire process takes several days, making it difficult to meet the demands of industrial-scale mass production. As-cast materials are prone to coarse grains (micrometer-scale), numerous grain boundary defects, and localized component segregation, leading to significant performance fluctuations between batches and compromising device performance stability. Furthermore, traditional processes often produce block or thick sheet products that require secondary processing such as cutting and stamping before use in devices, increasing costs and causing magnetic performance degradation due to mechanical stress. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a Fe-Co-Al soft magnetic material, its preparation method, and its applications. By introducing Co into Fe3Al, Fe3CoAl alloy soft magnetic material is prepared according to an atomic ratio of Fe:Co:Al = 3:1:1. A short-time annealing process, combining 30 m / s strip spinning with rapid cooling and 450°C for only 0.5 hours, is employed. This process significantly reduces the coercivity to 28.5 Oe while maintaining a high saturation magnetization, a 27.7% reduction compared to Fe3Al prepared using the same process. This process shortens the preparation cycle by more than 80%, and the thin strip morphology can be directly adapted to high-frequency devices, providing a new technical path for the industrial application of low-cost, low-loss soft magnetic materials.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing Fe-Co-Al soft magnetic materials, comprising the following steps:

[0009] 1) Fe:Co:Al was melted according to the atomic ratio Fe:Co:Al=3:1:1 to obtain Fe3CoAl alloy liquid;

[0010] 2) Spin the Fe3CoAl alloy liquid obtained in step 1) into a thin strip;

[0011] 3) Anneal the thin strip described in step 2), then immerse it in an ice-water mixture at a constant temperature to obtain Fe-Co-Al soft magnetic material.

[0012] Preferably, the smelting in step 1) is carried out using argon arc smelting at 1500~2500℃.

[0013] Preferably, the conditions for the strip spinning in step 2) include: the Fe3CoAl alloy liquid is rapidly cooled into a thin strip at a roller speed of 30 m / s in an induction melting strip spinning device in an argon atmosphere.

[0014] Preferably, the thickness of the thin strip in step 2) is 20~100μm.

[0015] Preferably, the annealing conditions in step 3) include: a temperature of 450°C and a time of 0.5 hours.

[0016] Preferably, the soaking time in step 3) is 0.5 hours.

[0017] The present invention also provides a Fe-Co-Al soft magnetic material prepared by the preparation method described above, wherein the coercivity of the Fe-Co-Al soft magnetic material is 28.5 Oe.

[0018] The present invention also provides the application of the Fe-Co-Al soft magnetic material described in the above technical solution in reducing the coercivity of soft magnetic materials.

[0019] The beneficial effects of this invention are:

[0020] 1. Fe3CoAl compounds exhibit superior intrinsic soft magnetic properties compared to Fe3Al even in the as-cast state, with a saturation magnetization of 158.44 emu / g and a coercivity of 35.6 Oe. When Co is introduced and a 30 m / s rapid cooling process is used, the grains are refined and the compositional uniformity is improved, further reducing the coercivity to 31.4 Oe. After a short annealing treatment at 450℃ for only 0.5 h, the internal stress is eliminated, the atomic order is improved, and the coercivity is reduced to 28.5 Oe, which is 27.7% lower than Fe3Al (39.4 Oe) produced by the same process, and the magnetic field sensitivity is significantly enhanced.

[0021] 2. The Fe3CoAl soft magnetic material prepared by this invention, under a process of rapid cooling followed by short-time annealing at 450℃, only requires 0.5 hours of annealing to achieve excellent comprehensive properties, including a saturation magnetization of 162 emu / g and a coercivity of 28.5 Oe. In contrast, Fe3Al requires 1 hour of annealing to achieve similar comprehensive properties, and its coercivity is still as high as 39.4 Oe. This invention reduces the annealing time by 50%, significantly improving the preparation efficiency.

[0022] 3. After being treated with a spinning process, Fe3CoAl soft magnetic material undergoes rapid cooling to refine the grains to the nanoscale, resulting in a significant reduction in coercivity, which meets the core requirements of soft magnetic materials: "easy to magnetize and easy to demagnetize". At the same time, after short-time annealing, the saturation magnetization recovers to 162 emu / g, achieving a balance between high magnetization and low coercivity. Its overall magnetic performance adaptability is superior to that of traditional Fe3Al soft magnetic materials.

[0023] 4. This high-performance soft magnetic material can be prepared by "argon arc melting and rapid cooling of the strip". The preparation method is simple, easy to operate, and has few processes, and has good prospects for industrial application.

[0024] 5. Fe3CoAl soft magnetic materials exhibit good toughness after being processed by spinning, which can ensure structural stability during the molding process. At the same time, thanks to the refined grain structure formed by the spinning process, even without brittleness, Fe3CoAl soft magnetic powder materials can be easily obtained through conventional grinding, which is convenient for subsequent mixing with resin materials for extrusion, injection molding, and die casting into various required shapes.

[0025] 6. This preparation process has a short heat treatment time, a short production cycle, and high efficiency.

[0026] 7. Fe3CoAl compounds have simple formulations, with raw materials consisting only of Fe, Co, and Al, and no precious elements. They are easy to operate, have a short process, and have broad prospects for industrial application. The raw materials do not contain volatile elements and are easy to synthesize. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0028] Figure 1 The XRD patterns of Fe3CoAl after all processes and annealing treatments are shown. Fe-Co-Al soft magnetic materials with the chemical formula Fe3CoAl are obtained by tape spinning and rapid cooling or heat treatment. The resulting materials have a DO3-type crystal structure. At room temperature, the saturation magnetization is 144-163 emu / g and the coercivity is 28.5-37.8 Oe.

[0029] Figure 2 XRD patterns of all processes and annealing treatments of Fe3Al;

[0030] Figure 3 The hysteresis loop of as-cast Fe3CoAl at room temperature;

[0031] Figure 4 The hysteresis loop of as-cast Fe3Al at room temperature;

[0032] Figure 5 The hysteresis loop of as-cast Fe3CoAl at room temperature after annealing at 700℃ for 48 hours;

[0033] Figure 6 The hysteresis loop of as-cast Fe3Al at room temperature after annealing at 700℃ for 48 hours;

[0034] Figure 7 The hysteresis loop of the Fe3CoAl thin strip at room temperature;

[0035] Figure 8 The hysteresis loop of the Fe3Al thin strip at room temperature;

[0036] Figure 9The hysteresis loop of Fe3CoAl thin strips at room temperature after annealing at 450℃ for 0.5 hours.

[0037] Figure 10 The hysteresis loop of Fe3Al thin strip at room temperature after annealing at 450℃ for 1 hour;

[0038] Figure 11 It is Fe2+. 85 Co0. 15 Magnetic field hysteresis loops at room temperature of Al ribbons and Fe2.7Co0.3Al ribbons after annealing at 450℃ for 0.5 hours;

[0039] Figure 12 The hysteresis loops of Fe3CoAl thin strips annealed at 450℃ for 0.5 hours are compared with those of the comparative Fe3Al thin strips annealed at 450℃ for 1 hour.

[0040] Figure 13 As-cast Fe3Co 1.5 The hysteresis loop of Al at room temperature. Detailed Implementation

[0041] This invention provides a method for preparing Fe-Co-Al soft magnetic materials, comprising the following steps:

[0042] 1) Fe:Co:Al was melted according to the atomic ratio Fe:Co:Al=3:1:1 to obtain Fe3CoAl alloy liquid;

[0043] 2) Spin the Fe3CoAl alloy liquid obtained in step 1) into a thin strip;

[0044] 3) Anneal the thin strip obtained in step 2), then immerse it in an ice-water mixture until it reaches a constant temperature to obtain Fe-Co-Al soft magnetic thin strip.

[0045] This invention relates to a Fe3CoAl alloy liquid obtained by melting Fe:Co:Al in an atomic ratio of 3:1:1. In this invention, argon arc melting is preferably used for the melting process. This invention does not specifically limit the argon arc melting method; any method capable of melting metal is applicable, and those skilled in the art can employ conventional methods.

[0046] This invention involves spinning the Fe3CoAl alloy liquid into a thin strip. Preferably, the spinning conditions include: rapidly cooling the Fe3CoAl alloy liquid into a thin strip at a roller speed of 30 m / s in an induction melting spinning device under an argon atmosphere. Preferably, the thickness of the thin strip is 20-100 μm.

[0047] This invention involves annealing the thin strip, then immersing it in an ice-water mixture at a constant temperature to obtain an Fe-Co-Al soft magnetic thin strip. In this invention, the annealing conditions preferably include a temperature of 450°C and a time of 0.5 hours. In this invention, the immersion time is preferably 0.5 hours.

[0048] The present invention also provides a Fe-Co-Al soft magnetic material prepared by the preparation method described above, wherein the coercivity of the Fe-Co-Al soft magnetic material is 28.5 Oe.

[0049] The present invention also provides the application of the Fe-Co-Al soft magnetic material described in the above technical solution in reducing the coercivity of soft magnetic materials.

[0050] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] A method for preparing Fe-Co-Al soft magnetic material includes the following steps:

[0053] Step (1) Weigh the raw materials Fe, Co and Al according to the atomic ratio of 3:1:1, and prepare Fe3CoAl alloy by argon arc melting.

[0054] Step (2) The Fe3CoAl alloy prepared in step (1) is rapidly cooled into a thin strip at a roller speed of 30 m / s in an induction melting and strip spinning device in an argon atmosphere.

[0055] To determine the composition and structure of the sample, X-ray diffraction was performed. The test results are as follows: Figure 1 As shown, Fe3CoAl material has a single-phase, fully ordered cubic crystal structure of type DO3.

[0056] To test the hysteresis loop of the sample at room temperature, the magnetic properties of the sample were measured using a vibrating sample magnetometer (VSM). The specific method is as follows:

[0057] A sample of 1-20 mg was selected, and an external magnetic field of up to 2 T was applied. The Fe3CoAl soft magnetic material obtained in step (1) was placed in the direction of the external magnetic field. Its magnetic moment had reached saturation under the 2T external magnetic field, the saturation magnetization (Ms) was 158 emu / g, and the coercivity was 35.6 Oe. The test results are as follows. Figure 3 As shown.

[0058] Comparative Example 1

[0059] According to the atomic ratio Fe:Al = 3:1, the raw materials Fe and Al were weighed, and Fe3Al alloy ingots were prepared using the same argon arc melting method as in Example 1.

[0060] The X-ray results of the Fe3Al soft magnetic material obtained after XRD and VSM tests under the same conditions are as follows: Figure 2 As shown, it exhibits a single-phase crystal structure of the DO3 type. The saturation magnetization of the as-cast Fe3Al is only 144 emu / g, and the coercivity is 52.1 Oe. The test results are as follows: Figure 4 .

[0061] Comparative conclusions: The Ms of as-cast Fe3CoAl is significantly higher than that of as-cast Fe3Al, while the Hc is significantly lower, indicating that the introduction of Co element effectively improves the intrinsic soft magnetic properties.

[0062] To demonstrate the effect of the annealing process on the material properties, Example 2 is provided, in which Fe3CoAl soft magnetic material was prepared with an annealing temperature of 700℃ and an annealing time of 48 hours.

[0063] Example 2

[0064] A method for preparing Fe-Co-Al soft magnetic material includes the following steps:

[0065] Step (1) Weigh the raw materials Fe, Co and Al according to the atomic ratio Fe:Co:Al = 3:1:1, and prepare Fe3CoAl alloy by argon arc melting.

[0066] Step (2) The Fe3CoAl alloy prepared in step (1) is sealed in a vacuum quartz tube and heat-treated in an annealing furnace at 700°C for 48 hours. After heat treatment, it is placed in an ice-water mixture and rapidly cooled to room temperature to obtain Fe3CoAl soft magnetic material.

[0067] The X-ray results of the obtained Fe3CoAl soft magnetic material are as follows: Figure 1 As shown, it exhibits a single-phase crystal structure of type DO3. This proves that the heat treatment process can generate a uniformly distributed and structurally stable single phase. The magnetic properties of the obtained Fe3CoAl soft magnetic material are as follows: coercivity of 37.8 Oe and saturation magnetization of 163 emu / g at room temperature. The test results are as follows. Figure 5 .

[0068] Comparative Example 2

[0069] Fe and Al were weighed according to an atomic ratio of Fe:Al = 3:1, and Fe3Al bulk material was prepared by argon arc melting and annealing at 700°C for 48 hours, which was exactly the same as in Example 4.

[0070] The X-ray results of the Fe3Al soft magnetic material obtained after XRD and VSM tests under the same conditions are as follows: Figure 2 As shown, it exhibits a single-phase crystal structure of type DO3. The coercivity of Fe3Al annealed at 700℃ for 48 hours in the as-cast state is 54.9 Oe, and the saturation magnetization is 160 emu / g. The test results are as follows... Figure 6 .

[0071] Comparative conclusion: Under the long-term annealing process at 700℃, the Ms of Fe3CoAl is higher than that of Fe3Al, and the Hc is much lower than that of Fe3Al, which further confirms the significant effect of Co substitution on increasing the saturation magnetization Ms and reducing the coercivity Hc.

[0072] To demonstrate the effect of the tape spinning and rapid cooling process on material properties, Examples 3 and 4 are provided, in which Fe3CoAl soft magnetic materials were prepared with tape spinning without annealing and tape spinning followed by annealing.

[0073] Example 3

[0074] A method for preparing Fe-Co-Al soft magnetic material includes the following steps:

[0075] Step (1) Weigh the raw materials Fe, Co and Al according to the atomic ratio Fe:Co:Al = 3:1:1, and prepare Fe3CoAl alloy by argon arc melting.

[0076] Step (2) The Fe3CoAl alloy prepared in step (1) is rapidly cooled into a thin strip at a roller speed of 30 m / s in an induction melting and spinning device in an argon atmosphere to obtain Fe3CoAl soft magnetic material.

[0077] The X-ray results of the obtained Fe3CoAl soft magnetic material are as follows: Figure 1 As shown, it exhibits a single-phase crystal structure of type DO3.

[0078] The saturation magnetization (Ms) of the obtained Fe3CoAl soft magnetic material is 144 emu / g, and the coercivity is 31.4 Oe. The test results are as follows: Figure 7 As shown.

[0079] Compared to the as-cast state, Ms decreased slightly after strip spinning (due to internal stress and grain refinement introduced by rapid cooling), but Hc decreased from 35.6 Oe to 31.4 Oe, a reduction of 11.8%, indicating that the fine-grained structure formed by rapid cooling of strip spinning helps to reduce coercivity and improve magnetic field sensitivity.

[0080] Comparative Example 3

[0081] Fe3Al thin strips were prepared by weighing raw materials Fe and Al according to the atomic ratio Fe:Al = 3:1 and using the same argon arc melting and 30m / s belt spinning and rapid cooling process as in Example 3.

[0082] The X-ray results of the Fe3Al soft magnetic material obtained after XRD and VSM tests under the same conditions are as follows: Figure 2 As shown, it exhibits a single-phase crystal structure of type DO3. The saturation magnetization of unannealed Fe3Al obtained by 30 m / s sweep spun test is 149 emu / g, and the coercivity is 35.5 Oe. The test results are as follows: Figure 8 .

[0083] Comparative conclusions: After the belt spinning, the Ms of Fe3Al was slightly higher than that of Fe3CoAl, but the Hc of Fe3CoAl was significantly lower than that of Fe3Al, indicating that the rapid cooling after belt spinning had a more significant effect on inhibiting the coercivity of Fe3CoAl.

[0084] Example 4

[0085] A method for preparing Fe-Co-Al soft magnetic material includes the following steps:

[0086] Step (1) Weigh the raw materials Fe, Co and Al according to the atomic ratio Fe:Co:Al = 3:1:1, and prepare Fe3CoAl alloy by argon arc melting.

[0087] Step (2) The Fe3CoAl alloy prepared in step (1) is rapidly cooled into a thin strip at a roller speed of 30 m / s in an induction melting and strip spinning device in an argon atmosphere.

[0088] Step (3) The thin strip Fe3CoAl prepared in step (2) is sealed in a vacuum quartz tube and heat-treated in an annealing furnace at 450°C for 0.5 hours. After heat treatment, it is placed in an ice-water mixture to cool rapidly to room temperature and soaked for half an hour to obtain Fe3CoAl soft magnetic material.

[0089] The X-ray results of the obtained Fe3CoAl soft magnetic material are as follows: Figure 1 As shown, it exhibits a single-phase crystal structure of the DO3 type. This proves that both the strip spinning and rapid cooling processes and the heat treatment process can generate a uniformly distributed and structurally stable single phase.

[0090] The magnetic properties of the obtained Fe3CoAl soft magnetic material, such as Figure 9As shown, the coercivity at room temperature is 28.5 Oe, and the saturation magnetization is 162 emu / g. Compared to the as-cast state, Ms increases by 2.2%, and Hc decreases by 20.0%; compared to the unannealed state after strip spinning, Ms increases by 12.5%, and Hc decreases by 9.2%. Short-time annealing at 450℃ effectively eliminates internal stress from strip spinning and promotes ordered atomic occupancy, thereby significantly reducing Hc while increasing Ms, and greatly improving magnetic field sensitivity. It can be demonstrated that the strip spinning process has a significant impact on the soft magnetic properties of the material. When the roller speed is 30 m / s and the heat treatment is carried out at 450℃ for 0.5 h, the saturation magnetization of the material is 162 emu / g, which is the maximum saturation magnetization of the material. Therefore, annealing after strip spinning has a significant impact on the soft magnetic properties of the material.

[0091] Comparative Example 4

[0092] According to the atomic ratio Fe:Al = 3:1, the raw materials Fe and Al were weighed and Fe3Al thin strips were prepared using the same argon arc melting, 30m / s strip spinning and rapid cooling and 450℃ annealing process as in Example 4. The annealing time was 1 hour.

[0093] The X-ray results of the Fe3Al soft magnetic material obtained after XRD and VSM tests under the same conditions are as follows: Figure 2 As shown, it exhibits a single-phase crystal structure of type DO3. The saturation magnetization of Fe3Al after strip spinning and annealing at 450℃ for 1 hour is 171 emu / g, and the coercivity is 39.4 Oe. The test results are as follows... Figure 10 .

[0094] Comparative Conclusions: Under the 450℃ annealing process, Fe3CoAl requires only 0.5 hours of annealing, resulting in a Hc concentration of 28.5 Oe; Fe3Al requires 1 hour of annealing, yet its Hc concentration remains as high as 39.4 Oe. Fe3CoAl exhibits a 27.7% lower coercivity compared to Fe3Al, and its annealing time is shortened by 50%. Although the Ms of Fe3CoAl is slightly lower than that of Fe3Al, its lower coercivity leads to improved magnetic field sensitivity and lower loss characteristics, making it more valuable for practical applications in high-frequency electronic devices.

[0095] Comparative analysis of magnetic field sensitivity

[0096] Figure 12 This is a comparison diagram of the hysteresis loops of the Fe3CoAl thin strip of the present invention (Example 4) and the comparative Fe3Al thin strip (Comparative Example 4).

[0097] like Figure 12As shown in the enlarged partial view, in the initial magnetization curve of the Fe3CoAl thin strip of the present invention, in the low magnetic field region (|H| ≤ 200 Oe), the magnetization curve is generally closer to the Y-axis. Specifically, under any identical weak magnetic field H, the magnetization intensity M of Fe3CoAl is significantly higher than that of the comparative Fe3Al, that is, the curve of Fe3CoAl leaves the X-axis earlier and rises closer to the Y-axis.

[0098] This characteristic indicates that Fe3CoAl can increase its magnetization intensity more quickly when excited by a weak magnetic field, with a steeper initial slope in its magnetization curve, a faster deviation from the X-axis, and a closer adherence to the Y-axis. This directly proves that the material of this invention has superior magnetization sensitivity (i.e., weak magnetic field response capability).

[0099] from Figure 12 The full-field hysteresis loop shows that the coercivity of Fe3CoAl (28.5 Oe) is significantly lower than that of Fe3Al (39.4 Oe), while their saturation magnetization is similar. Combined with the behavior of the low-field region being closer to the Y-axis, this indicates that the introduction of Co and the optimized strip-spinning and short-time annealing process effectively reduce magnetocrystalline anisotropy and domain wall pinning effects, enabling the material to be rapidly magnetized under weak magnetic fields. This makes it particularly suitable for soft magnetic devices requiring rapid response, such as high-frequency transformers and magnetic sensors. To further verify the unique advantages of the Fe3CoAl composition of this invention and exclude the possibility of other Co content ratios, Comparative Example 5 is provided below, providing a lateral comparison of Fe-Co-Al variants with different Co contents.

[0100] Comparative Example 5

[0101] (1) Samples with low Co content

[0102] Fe2 was prepared by weighing raw materials Fe, Co and Al according to the atomic ratio Fe:Co:Al = 2.85:0.15:1 and using the same argon arc melting, 30 m / s belt spinning quenching and annealing at 450°C for 0.5 h process as in Example 3. 85 Co0. 15 Al thin bands.

[0103] Under the same VSM conditions, its saturation magnetization was only 127 emu / g, and its coercivity was 36.2 Oe. The test results are as follows: Figure 11 .

[0104] According to the atomic ratio Fe:Co:Al = 2.7:0.3:1, the raw materials Fe, Co and Al were weighed, and Fe2.7Co0.3Al thin strips were prepared by rapid cooling at 30 m / s and annealing at 450℃ for 0.5 h.

[0105] Under the same VSM conditions, its saturation magnetization was only 131 emu / g, and its coercivity was 39.8 Oe. The test results are as follows: Figure 11 .

[0106] (2) Samples with high Co content

[0107] According to the atomic ratio of Fe:Co:Al = 3:1.5:1, the raw materials Fe, Co and Al were weighed, and a cast alloy was prepared using the same argon arc melting method as in Example 1. The room temperature hysteresis loop, as shown in Figure 13, was measured by VSM, with a saturation magnetization of 145 emu / g and a coercivity of 40.2 Oe.

[0108] Comparative conclusions: When the Co content is too low, the saturation magnetization of the alloy is significantly low (≤131 emu / g), while the coercivity is high (≥36.2 Oe); when the Co content is too high, the coercivity of the as-cast alloy increases to 40.2 Oe, and the saturation magnetization decreases to 145 emu / g, both inferior to Example 1 of this invention. Only the preferred Fe:Co:Al ratio of 3:1:1 in this invention achieves excellent comprehensive performance of 162 emu / g saturation magnetization and 28.5 Oe coercivity after strip spinning and short-time annealing. Therefore, the 3:1:1 atomic ratio selected in this invention is the optimal composition. This material is synthesized for the first time. The soft magnetic properties of the Fe3CoAl compound can be activated by induction melting and strip spinning followed by rapid cooling. The source of soft magnetism is directly related to grain size and degree of crystallinity. This indicates that the strip spinning rapid cooling process in this compound yields smaller grains. The heat treatment process directly promotes the increase of crystallinity in the compound. The soft magnetism that appears at room temperature is of great significance for in-depth research and development of the magnetic properties of Fe3CoAl compounds.

[0109] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing Fe-Co-Al soft magnetic material, characterized in that, Includes the following steps: 1) Fe:Co:Al was melted according to the atomic ratio Fe:Co:Al=3:1:1 to obtain Fe3CoAl alloy liquid; 2) Spin the Fe3CoAl alloy liquid obtained in step 1) into a thin strip; 3) Anneal the thin strip described in step 2), then immerse it in an ice-water mixture at a constant temperature to obtain Fe-Co-Al soft magnetic material.

2. The preparation method according to claim 1, characterized in that, Step 1) The smelting is carried out using argon arc smelting at 1500~2500℃.

3. The preparation method according to claim 1, characterized in that, Step 2) The conditions for the strip spinning include: the Fe3CoAl alloy liquid is rapidly cooled into a thin strip at a roller speed of 30m / s in an induction melting strip spinning device in an argon atmosphere.

4. The preparation method according to claim 1, characterized in that, Step 2) The thickness of the thin strip is 20~100μm.

5. The preparation method according to claim 1, characterized in that, The annealing conditions in step 3) include: a temperature of 450°C and a time of 0.5 hours.

6. The preparation method according to claim 1, characterized in that, Step 3) The soaking time is 0.5 hours.

7. A Fe-Co-Al soft magnetic material prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The coercivity of the Fe-Co-Al soft magnetic material is 28.5 Oe.

8. The application of the Fe-Co-Al soft magnetic material according to claim 7 in reducing the coercivity of soft magnetic materials.

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