Hot press molding method of amorphous soft magnetic powder

Abstract

The invention discloses a hot press molding method of amorphous soft magnetic powder. The method comprises the following steps: carrying out heat treatment on amorphous powder granulation powder to Tx150 DEG C to Tx50 DEG C under a protective atmosphere, and keeping the temperature for 5-90 minutes; and then the powder is transferred into a mold, hot pressing is conducted for 30-180 seconds in the temperature range from Tg to Tx and under the gauge pressure of 100-600 MPa, a high-density formed body is obtained, and the high-density amorphous soft magnetic powder core can be obtained after sintering. According to the method, the pressing gauge pressure is remarkably reduced, the relative density is improved, the magnetic conductivity is improved, the iron loss is reduced, the process adaptability is high, the method can be achieved through simple transformation of conventional powder metallurgy equipment, the controllability is high, and the method is suitable for industrial preparation of the high-performance amorphous soft magnetic material.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy, and more particularly to a hot pressing method for forming amorphous soft magnetic powder. Background Technology

[0002] Amorphous alloy powders have excellent soft magnetic properties, such as high permeability, low coercivity, and low iron loss, and have broad application prospects in electronic devices, motor cores, and transformers. However, amorphous soft magnetic powders are prepared by rapid cooling technology, resulting in a long-range disordered atomic arrangement. This unique preparation process leads to a large amount of frozen internal stress within the material. These internal stresses have a serious negative impact on the magnetic properties of the material: (1) Increased coercivity: Internal stresses "pin" the domain walls, hindering their movement. To magnetize or demagnetize the material, a larger external magnetic field needs to be applied, which manifests as a significant increase in coercivity. (2) Decreased permeability: Due to the difficulty of magnetization, the permeability of the material decreases significantly. (3) Increased magnetic loss: In an alternating magnetic field, the repeated movement of the domain walls is hindered, resulting in additional energy consumption and increased core loss. This is fatal for power electronic devices that pursue high efficiency.

[0003] In addition, amorphous alloy powders face the following technical challenges in powder metallurgy forming: (1) High pressure of pressing. Traditional cold pressing processes usually require extremely high pressing pressure to achieve powder densification, which not only leads to severe mold wear but also significantly increases production costs; (2) Low relative density. Even under high pressure, the relative density obtained by traditional processes is usually below 85%, which is difficult to meet the requirements of high-performance applications for permeability and mechanical strength. The relative density is obtained by dividing the density of the magnetic powder core by the density of the powder and multiplying by 100%. The density of the powder is obtained by Archimedes' method, while the density of the magnetic powder core is calculated by dividing the weight by the volume. The higher the relative density, the greater the density of the magnetic powder core after powder pressing.

[0004] To address the aforementioned issues, researchers have proposed a method for preparing amorphous and nanocrystalline magnetic powder cores based on hot pressing. For example, Chinese patent application CN120072501A discloses a method for preparing amorphous and nanocrystalline magnetic powder cores based on hot pressing, which proposes a hot pressing method at temperatures ranging from 250℃ to 550℃ and pressures ranging from 100MPa to 500MPa for 18 to 22 seconds. This method achieves a certain degree of density and permeability improvement, but the improvement is small and the effect is not significant. This is because there are many voids between the powder particles, resulting in poor thermal conductivity. In addition, the high efficiency of the pressing equipment and the short heating time of the powder easily lead to uneven heating of the powder. The powder temperature cannot reach the specified temperature simultaneously, resulting in uneven internal stress distribution, which in turn affects the structural uniformity and the consistency of magnetic properties. Due to insufficient density and uneven molding structure, the product has high iron loss, failing to fully utilize the excellent magnetic properties of the amorphous alloy itself. Furthermore, for example, application CN116313480A discloses a high-density amorphous soft magnetic composite material and its preparation method, which involves directly heating the powder from room temperature to 180±20℃ within the mold cavity during pressing. However, the resulting amorphous soft magnetic composite material, under 100kHz and 50mT conditions, still exhibits a minimum iron loss of 168.4kw / m³ (i.e., at least 500mW / cm³ under 100kHz and 100mT conditions), indicating minimal performance improvement. This is because the heating time is relatively short, the achievable temperature is low, the reduction in internal stress of the powder is minimal, and significant internal stress remains. Additionally, insufficient pressing strength further limits the density increase, resulting in low permeability and high iron loss in the pressed amorphous soft magnetic composite material. Another example is the disclosed... Application document CN117198731A discloses an amorphous magnetic powder core and its preparation method. During pressing, the temperature reached by the amorphous alloy powder after heating (around 800K, or 500℃) is increased, thereby improving the permeability of the amorphous magnetic powder core. However, under conditions of 100kHz and 1000Gs (100mT), the iron loss remains relatively high (around 300mW / cm³). This is still due to the short heating time, uneven heating of the powder, and the inability of the powder to reach the specified temperature simultaneously, resulting in uneven internal stress distribution and uneven density of the pressed magnetic powder core, affecting the consistency of magnetic properties. While increasing the heating time of the powder during pressing to ensure simultaneous reaching of the specified temperature can uniformly and significantly reduce the internal stress of the powder, thus reducing the pressing strength required to produce a high-density magnetic core, it also increases the waiting time for the pressing equipment to press the next batch of powder, thereby reducing the pressing efficiency.

[0005] Therefore, there is an urgent need for a method to reduce the internal stress of amorphous powder, further improve the soft magnetic properties of amorphous powder, and achieve high relative density, high magnetic properties, and uniform structure of amorphous soft magnetic powder under lower surface pressure. Summary of the Invention

[0006] The purpose of this invention is to provide a hot pressing method for amorphous soft magnetic powder, which aims to overcome the problems of high internal stress, high surface pressure, low relative density, and unstable performance of amorphous alloy powder in the prior art. The invention provides a method that can reduce the internal stress of the powder and prepare amorphous soft magnetic powder with high density, excellent performance, and uniform structure under lower pressing pressure.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A hot pressing method for forming amorphous soft magnetic powder includes at least the following steps: (1) Stress relief heat treatment and heat preservation steps: The amorphous soft magnetic powder granules are heated to a certain temperature under a protective atmosphere. T 1. Perform stress-relieving heat treatment. T 1. Satisfy T x - 150℃≤ T 1≤ T x - 50℃, of which T x The crystallization temperature of the amorphous alloy is used for holding at this temperature for 5–90 minutes. (2) Pressing step: Keep the heat-treated powder at a certain temperature T 1. Transfer to a mold under a protective atmosphere, at a temperature T 2. Hot pressing at a gauge pressure of 100–600 MPa. T 2. Satisfy T g ≤ T 2≤ T x ,in T g The glass transition temperature of the amorphous alloy is used, and the holding time during the pressing process is 30–180 seconds. (3) Sintering step: The molded body prepared by the above method is sintered, and a high-density amorphous soft magnetic powder core can be obtained after sintering.

[0008] Preferably, the stress-relieving heat treatment and the holding temperature T1 satisfy T x -120℃≤T1≤T x -80℃.

[0009] Preferably, the heat treatment and heat preservation step involves a heat preservation time of 30-60 minutes.

[0010] Preferably, the T g The pressing temperature in the above hot pressing steps T2. Satisfy T g +10℃≤ T 2< T x .

[0011] Preferably, the T g The pressure holding time in the above hot pressing steps is 60 to 120 seconds.

[0012] Preferably, the amorphous soft magnetic powder is selected from one or more of Fe-based, Co-based, or Ni-based amorphous alloy powders.

[0013] Preferably, the particle size D of the amorphous soft magnetic powder is... 50 It is 5–20 μm.

[0014] Preferably, the protective atmosphere is nitrogen or argon.

[0015] Preferably, the relative density of the molded body obtained by the above hot pressing method is ≥90% calculated using Archimedes' method and mass-to-volume method.

[0016] In conclusion, compared with the prior art, the present invention has the following significant advantages: By employing a two-step process of "heat treatment – ​​hot pressing", the powder has already released internal stress and the temperature has been homogenized before pressing, thereby effectively reducing the pressing pressure, extending the mold life, and reducing costs. The method of this invention can achieve a relative density of over 90%, which is more than 5 percentage points higher than the prior art. At the same time, it significantly improves the magnetic permeability of the molded body and greatly reduces iron loss, and its overall performance is significantly better than the prior art.

[0017] Furthermore, this invention achieves a uniform powder temperature distribution through stress-relief heat treatment followed by heat preservation, resulting in a molded body with a uniform microstructure and consistent performance. Compared to processes without stress-relief heat treatment and heat preservation, this method offers advantages in densification control and thermal field equalization, making it particularly suitable for high-performance pressing manufacturing of large-size and complex-shaped magnetic components.

[0018] This invention T 1 and T 2. It has a wide range of permissible processes and strong process adaptability. It can be achieved by simply modifying conventional powder metallurgy equipment. It is easy to control and suitable for continuous and industrialized production. At the same time, it reduces the pressing pressure and effectively overcomes the problems of severe mold wear and high energy consumption. Attached Figure Description

[0019] Figure 1 DSC curves of Fe-Si-BPC-Cr amorphous alloy powder; Figure 2The temperature-time process curve of this invention shows the heat treatment temperature. T 1. Insulation time t 1. Pressing temperature T 2. Pressing process heat preservation and pressure holding time t 2. Cooling process after demolding. Detailed Implementation

[0020] The following description is merely a preferred embodiment of the present invention, and the scope of protection is not limited to this embodiment. All technical solutions falling within the scope of the present invention should be considered within the protection scope of the present invention. It should also be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the protection scope of the present invention.

[0021] A hot pressing method for forming amorphous soft magnetic powder includes at least the following steps: (1) Stress relief heat treatment and heat preservation steps: The amorphous soft magnetic powder granules are heated to a certain temperature under a protective atmosphere. T 1. Perform stress-relieving heat treatment. T 1. Satisfy T x - 150℃≤ T 1≤ T x - 50℃, of which T x The crystallization temperature of the amorphous alloy is used for holding at this temperature for 5–90 minutes. (2) Pressing step: Keep the heat-treated powder at a certain temperature T 1. Transfer to a mold under a protective atmosphere, at a temperature T 2. Hot pressing at a gauge pressure of 100–600 MPa. T 2. Satisfy T g ≤ T 2≤ T x ,in T g The glass transition temperature of the amorphous alloy is used, and the holding time during the pressing process is 30–180 seconds. (3) Sintering step: The molded body prepared by the above method is sintered, and a high-density amorphous soft magnetic powder core can be obtained after sintering.

[0022] Preferably, the stress-relieving heat treatment and the holding temperature T1 satisfy T x -120℃≤T1≤T x -80℃.

[0023] Preferably, the heat treatment and heat preservation step involves a heat preservation time of 30-60 minutes.

[0024] Preferably, the pressing temperature in the hot pressing step above Tg is... T 2. Satisfy T g +10℃≤ T 2< T x .

[0025] Preferably, the T g The pressure holding time in the above hot pressing steps is 60 to 120 seconds.

[0026] Preferably, this method is applicable to one or more amorphous soft magnetic powders based on Fe, Co, or Ni, and has a wide range of applications and high practicality.

[0027] Preferably, the particle size D of the amorphous soft magnetic powder is... 50 It is 5–20 μm.

[0028] Preferably, the protective atmosphere is nitrogen or argon.

[0029] Preferably, the relative density of the molded body obtained by the above hot pressing method is ≥90% calculated using Archimedes' method and mass-to-volume method.

[0030] Working principle: This method involves preheating the amorphous alloy powder in the storage tank to a certain temperature. T 1. Then, put the contents of the storage tank into the storage tank. T 1. Powder at a specific temperature is sequentially fed into the pressing mold of the pressing equipment, and then heated to a specific temperature within the pressing mold. T 2; Compared to the traditional hot pressing method: first, powder at room temperature in the storage tank is conveyed to the pressing mold, and then the powder is heated to a certain temperature in the pressing mold. T 2. The heating time required in this application is shorter because a large amount of powder has already been preheated and kept at a certain temperature. t After a period of time, a fixed amount of powder is fed into the pressing mold and heated before pressing. This allows for direct pressing without reducing pressing efficiency, and the resulting soft magnetic powder core has higher density and magnetic properties. By heating amorphous alloy powder to a specified temperature range, the plasticity and flowability of the powder can be improved, reducing the gauge pressure required for powder pressing and thus better increasing the density of the pressed magnetic core.

[0031]

Example 1

[0032] First, the amorphous soft magnetic powder is granulated and placed in a high-temperature resistant crucible for stress-relief heat treatment under a nitrogen protective atmosphere to prevent oxidation of the powder during heating. Heat treatment temperature. T 1 is set to 440℃, that is T x -100℃, heat preservation time t 1 = 30 minutes, which makes the internal temperature distribution of the powder tend to be uniform and eliminates the temperature difference between particles.

[0033] Subsequently, the heat-treated powder is transferred to a mold preheated to the target temperature. During the transfer, the powder is maintained at the stress-relief heat treatment temperature so that it can quickly and uniformly reach the predetermined hot-pressing temperature after being transferred to the mold. Then, at the temperature... T 2 = 510℃ (equivalent to) T g Molding is performed under a hot pressing pressure of 500 MPa at +10℃, with a holding time of... t 2 = 60 seconds.

[0034] After hot pressing, the temperature is lowered to room temperature in a nitrogen atmosphere to obtain a dense amorphous soft magnetic molded body. The molded body can be heat-treated to obtain a soft magnetic powder core.

[0035] Test results show that the obtained sample has a relative density of 91.7%, a permeability of 108.9, and an iron loss of 137.71 mW / cm³ under conditions of 100 kHz and 100 mT. The amorphous soft magnetic powder core prepared by the method of this invention has a much higher relative density than products obtained by cold pressing and hot pressing without stress relief heat treatment and heat preservation; its permeability is significantly improved, and its iron loss is significantly reduced, and its overall soft magnetic properties are far superior to those of existing technologies.

[0036]

Example 2

[0037] First, the amorphous soft magnetic powder is granulated and placed in a high-temperature resistant crucible for stress-relief heat treatment under a nitrogen protective atmosphere to prevent oxidation of the powder during heating. The heat treatment temperature is set at 409℃. T x -150℃, keep warm for 90 minutes to make the internal temperature distribution of the powder more uniform and eliminate the temperature difference between particles.

[0038] Subsequently, the heat-treated powder is transferred to a mold preheated to the target temperature. During the transfer, the powder is maintained at the stress-relief heat treatment temperature so that it can quickly and uniformly reach the predetermined hot-pressing temperature after being transferred to the mold. Then, at a temperature of 507℃ (equivalent to... T g The hot pressing pressure of 600 MPa is applied for molding, and the holding time is 180 seconds.

[0039] After hot pressing, the temperature is lowered to room temperature in a nitrogen atmosphere to obtain a dense amorphous soft magnetic molded body. The molded body can be heat-treated to obtain a soft magnetic powder core.

[0040] Test results show that the obtained sample has a relative density of 92.2%, a permeability of 90.6, and an iron loss of 176.92 mW / cm³ under conditions of 100 kHz and 100 mT. The amorphous soft magnetic powder core prepared by the method of this invention has a much higher relative density than products obtained by cold pressing and hot pressing without stress relief heat treatment and heat preservation; its permeability is significantly improved, and its iron loss is significantly reduced, and its overall soft magnetic properties are far superior to those of existing technologies.

[0041]

Example 3

[0042] The powder was heat-treated to 472°C under a nitrogen protective atmosphere. T x -50℃, hold for 5 minutes. This holding time helps ensure uniform temperature distribution of fine particles and avoids localized stress concentration caused by uneven particle heating.

[0043] Subsequently, the heat-treated powder is transferred to a mold preheated to the target temperature. During the transfer, the powder is maintained at the stress-relief heat treatment temperature to ensure rapid and uniform attainment of the predetermined hot-pressing temperature after transfer to the mold. Then, at 512°C (equivalent to... T g +23℃,T x The molding process involves applying a hot pressing pressure of 100 MPa at a temperature of -10℃, with a holding time of 30 seconds.

[0044] After hot pressing, the temperature is lowered to room temperature in a nitrogen atmosphere to obtain a dense amorphous soft magnetic molded body. The molded body can be heat-treated to obtain a soft magnetic powder core.

[0045] Test results show that the obtained sample has a relative density of 90.1%, a permeability of 77.5, and an iron loss of 149.27 mW / cm³ under conditions of 100 kHz and 100 mT. The amorphous soft magnetic powder core prepared by the method of this invention has a much higher relative density than products obtained by cold pressing and hot pressing without stress relief heat treatment and heat preservation; its permeability is significantly improved, and its iron loss is significantly reduced, and its overall soft magnetic properties are far superior to those of existing technologies.

[0046] Comparative Example 1 Using the traditional cold pressing method, without stress-relief heat treatment and heat preservation steps, the same median particle size D of the powder in Example 1 was subjected to cold pressing at room temperature. 50 The granulated Fe-Si-BPC-Cr amorphous alloy powder with a particle size of 11.9 μm was pressed under a pressure of 600 MPa. After heat treatment, the resulting soft magnetic powder core had a relative density of 73.3%, a permeability of 40.6, and an iron loss of 294.37 mW / cm³ at 100 kHz and 100 mT.

[0047] Comparative Example 2 Using the traditional cold pressing method, without heat treatment and heat preservation steps, the same median particle size D of the powder in Example 1 was subjected to cold pressing at room temperature. 50 The granulated Fe-Si-BPC-Cr amorphous alloy powder with a particle size of 11.9 μm was pressed under a pressure of 1000 MPa. After heat treatment, the resulting soft magnetic powder core had a relative density of 79.1%, a permeability of 51.0, and an iron loss of 259.93 mW / cm³ at 100 kHz and 100 mT.

[0048] Comparative Example 3 Using the traditional cold pressing method, without heat treatment and heat preservation steps, the same median particle size D of the powder in Example 1 was subjected to cold pressing at room temperature. 50 The granulated Fe-Si-BPC-Cr amorphous alloy powder with a particle size of 11.9 μm was pressed under a pressure of 1800 MPa. After heat treatment, the resulting soft magnetic powder core had a relative density of 82.6%, a permeability of 64.7, and an iron loss of 218.10 mW / cm³ at 100 kHz and 100 mT.

[0049] Comparative Example 4 Using the traditional cold pressing method, without heat treatment and heat preservation steps, the same median particle size D of the powder in Example 1 was subjected to cold pressing at room temperature. 50 The granulated Fe-Si-BPC-Cr amorphous alloy powder with a particle size of 11.9 μm was pressed under a pressure of 2200 MPa. After heat treatment, the resulting soft magnetic powder core had a relative density of 84.0%, a permeability of 73.4, and an iron loss of 208.43 mW / cm³ at 100 kHz and 100 mT.

[0050] Comparative Example 5 The powder with the same median particle size D as in Example 1 was directly pressed in a mold at 510°C using a direct hot pressing method (without heat treatment). 50 Granulated Fe-Si-BPC-Cr amorphous alloy powder with a particle size of 11.9 μm was pressed under a pressure of 600 MPa. After heat treatment, a soft magnetic powder core was obtained with a relative density of 82.4%, a permeability of 64.1, and an iron loss of 219.44 mW / cm³ at 100 kHz and 100 mT.

[0051] Table 1 summarizes the pressing methods, pressures, and performance parameters of the magnetic powder cores in the examples and comparative examples.

[0052] Table 1 Stress relief heat treatment temperature and holding time Pressing temperature, holding time Pressure (gauge pressure) MPa relative density Permeability @100kHz <![CDATA[Iron loss mW / cm 3 > Example 1 <![CDATA[ T x -100℃30min]]> <![CDATA[ T g +10℃60s]]> 500 91.7% 108.9 137.71 Example 2 <![CDATA[ T x -150℃90min]]> <![CDATA[ T g 180s]]> 600 92.2% 90.6 176.92 Example 3 <![CDATA[ T x -50℃5min]]> <![CDATA[ T g +23℃30s]]> 100 90.1% 77.5 149.27 Comparative Example 1 / 3s at room temperature 600 73.3% 40.6 294.37 Comparative Example 2 / 3s at room temperature 1000 79.1% 51.0 259.93 Comparative Example 3 / 3s at room temperature 1800 82.6% 64.7 218.10 Comparative Example 4 / 3s at room temperature 2200 84.0% 73.4 208.43 Comparative Example 5 / <![CDATA[ T g +10℃60s]]> 600 82.4% 64.1 219.44 Note: Iron loss test conditions: 100kHz, 100mT.

[0053] The results of the examples and comparative examples clearly show that, compared with the traditional cold pressing process or the direct hot pressing method without heat treatment, the "heat treatment-hot pressing" two-step forming process proposed in this invention has significant advantages in many aspects.

[0054] First, this invention achieves uniform temperature distribution in the amorphous soft magnetic powder by heat-treating it before pressing, significantly reducing the difference in thermal stress between particles. Then, the powder is heated to... T g ≤ T 2≤ T x Within this range, the powder's elasticity decreases while its plasticity increases. This reduces the interaction forces between the pressing equipment and the powder, as well as the stress between the powder particles, during the pressing process when the powder deforms and aggregates. This allows for high-density molding at lower gauge pressures (only 100–600 MPa). This feature effectively overcomes the problems of severe mold wear and high energy consumption in traditional processes.

[0055] Secondly, heat treatment improves the plasticity and flowability of the powder, resulting in a more uniform structure and significantly reduced porosity in the pressed molded body. Actual measurements show that the relative density of the sample obtained using this invention can be increased to over 90%, which is more than 5 percentage points higher than that achieved using traditional methods.

[0056] Furthermore, the amorphous soft magnetic material prepared by this invention exhibits significantly improved magnetic properties. The permeability is significantly increased, and the iron loss is significantly reduced, both superior to products obtained by traditional methods. In addition, the performance fluctuations between different batches of samples are minimal, indicating that this method has excellent repeatability and stability; and T 1 and T 2. It has a wide permissible range, does not require a specific temperature, has strong process adaptability, is easy to control, reduces pressing conditions, and saves costs.

[0057] Meanwhile, Table 1 shows that the relative density of the magnetic cores produced by different stress-relief heat treatment + heat holding + hot pressing steps is not significantly different, all reaching over 90%, and the iron loss is all below 200 mW / cm². 3 It has a wide operating range under pressing conditions and strong process adaptability. Furthermore, according to... Figure 2 It can be seen that if the powder is heated from room temperature to the specified hot-pressing temperature T2, it takes a longer time to reach temperature equilibrium. However, the temperature rise from T1 to T2 is linear, and due to the smaller temperature difference, temperature equilibrium is reached more quickly. In other words, the time required to heat the powder to the specified hot-pressing temperature T2 is shorter, thus significantly improving the efficiency of pressing. The rapid heating rate and short heating time, according to thermodynamic properties, result in slower heating at higher temperatures. When the temperature reaches a certain critical value, the heating rate increases again. Therefore, heating amorphous soft magnetic powder to temperature T1 is the optimal temperature for transferring it to the mold for hot pressing. Because the powder at temperature T1 heats up quickly to temperature T2 during hot pressing, the heating time is short, thus not reducing pressing efficiency.

[0058] In summary, by introducing a controllable heat treatment combined with short-time hot pressing, this invention achieves high densification and performance optimization of amorphous powder under conditions of simple process and low energy consumption. It not only significantly reduces pressing pressure and improves the uniformity of material performance, but also makes the process more suitable for industrial promotion and mass production, fully verifying the effectiveness and practicality of the present invention.

Claims

1. A hot pressing method for forming amorphous soft magnetic powder, characterized in that, At least the following steps are included: (1) Stress relief heat treatment and heat preservation steps: The amorphous soft magnetic powder granules are heated to a certain temperature under a protective atmosphere. T 1. Perform stress-relieving heat treatment. T 1. Satisfy T x - 150℃≤ T 1≤ T x - 50℃, of which T x The crystallization temperature of the amorphous alloy is used for holding at this temperature for 5–90 minutes. (2) Pressing step: Keep the heat-treated powder at a certain temperature T 1. Transfer to a mold under a protective atmosphere, at a temperature T 2. Hot pressing at a gauge pressure of 100–600 MPa. T 2. Satisfy T g ≤ T 2≤ T x ,in T g The glass transition temperature of the amorphous alloy is used, and the holding time during the pressing process is 30–180 seconds. (3) Sintering step: The molded body prepared by the above method is sintered, and a high-density amorphous soft magnetic powder core can be obtained after sintering.

2. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, Stress-relieving heat treatment and holding temperature T 1. Satisfy T x - 120℃≤ T 1≤ T x - 80℃.

3. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The heat treatment and heat preservation steps involve a heat preservation time of 30-60 minutes.

4. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The T g The pressing temperature in the above hot pressing steps T 2. Satisfy T g +10℃≤ T 2< T x .

5. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The T g The pressure holding time in the above hot pressing steps is 60 to 120 seconds.

6. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The amorphous soft magnetic powder is selected from one or more of Fe-based, Co-based, or Ni-based amorphous alloy powders.

7. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The particle size D of the amorphous soft magnetic powder 50 It is 5–20 μm.

8. The hot pressing method for forming amorphous soft magnetic powder according to claim 1, characterized in that, The protective atmosphere is either nitrogen or argon.

9. A hot pressing method for forming amorphous soft magnetic powder according to any one of claims 1 to 5, characterized in that, The relative density of the obtained molded body, calculated using Archimedes' method and mass-to-volume method, is ≥90%.

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