A high DC superposition performance iron-silicon-aluminum soft magnetic alloy, its preparation method and its application

Abstract

This invention discloses a high DC superposition performance iron-silicon-aluminum soft magnetic alloy, its preparation method, and its applications. Belonging to the field of soft magnetic metal materials technology, the raw materials used are silicon 3-6 wt.%, aluminum 3-5 wt.%, nickel 1-3 wt.%, cobalt 0.5-1 wt.%, with the balance being iron, totaling 100 wt.%. During vacuum refining, a mixed rare earth alloy of 0.2 wt.% of the total silicon, aluminum, nickel, cobalt, and iron, and 0.5 wt.% carbon flakes are added. The novel iron-silicon-aluminum metal powder prepared by this invention can significantly improve the DC superposition performance of iron-silicon-aluminum magnetic powder core products, meeting the requirements of magnetic components to withstand large currents and high power. It can be used in power electronic components such as inverter inductors, energy storage inductors, and power correction factor inductors.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic materials technology, and in particular to a high DC superposition performance iron-silicon-aluminum soft magnetic alloy, its preparation method and its application. Background Technology

[0002] Ferrosilicon-aluminum alloys, also known as Sendstein alloys (Fe-9.6Si-5.4Al), possess magnetocrystalline anisotropy and saturation magnetostriction coefficients that are both close to zero, resulting in excellent soft magnetic properties. Ferrosilicon-aluminum magnetic powder cores are widely used in digital products, electronic communications, air conditioning, and new energy vehicles due to their affordable price and superior soft magnetic properties. Typically, ferrosilicon-aluminum magnetic powder cores are prepared by mixing soft magnetic metal powders with silicone rubber, followed by molding and stress-relief annealing to obtain the desired magnetic components. The commonly used preparation method for ferrosilicon-aluminum soft magnetic alloys is gas atomization, which yields powders with high sphericity and controllable particle size. With the rapid development of emerging industries such as new energy, wind power generation, photovoltaic inverters, and big data centers, higher demands are being placed on the ability of magnetic components to withstand high currents and high power (DC superposition performance). However, because traditional iron-silicon-aluminum alloys (Fe-9.6Si-5.4Al) have a high proportion of non-ferromagnetic elements (Si accounts for 9.6% by mass and Al accounts for 5.4% by mass, totaling 15 wt%), the saturation magnetic flux density of these alloys is reduced. Consequently, traditional iron-silicon-aluminum magnetic powder cores have poor ability to withstand high currents and high power, resulting in poor DC superposition performance. Furthermore, the high content of gaseous impurities such as oxygen and nitrogen in the iron-silicon-aluminum powder prepared by traditional gas atomization methods increases the coercivity of the material, reduces microstructure stability, and further deteriorates the soft magnetic properties of the iron-silicon-aluminum magnetic powder cores. Finally, the rapid cooling rate during gas atomization results in small grain sizes in the obtained iron-silicon-aluminum powder, which further increases the coercivity of the material and worsens the DC superposition performance. Summary of the Invention

[0003] One of the objectives of this invention is to provide a method for preparing a high DC superposition performance iron-silicon-aluminum soft magnetic alloy to solve the above-mentioned problems.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing a high DC superposition performance iron-silicon-aluminum soft magnetic alloy, wherein the method is a vacuum atomization method, and the raw materials used are silicon 3-6 wt.%, aluminum 3-5 wt.%, nickel 1-3 wt.%, cobalt 0.5-1 wt.%, with the balance being iron, totaling 100 wt.%; mixed rare earth alloys and carbon sheets are also added during vacuum refining.

[0006] The inventors of this application optimized the alloy composition ratio through extensive experiments, adding nickel and cobalt while reducing the proportion of non-magnetic elements silicon and aluminum to increase the proportion of ferromagnetic elements (Fe+Co+Ni) in the iron-silicon-aluminum alloy, thereby increasing the saturation magnetic flux density of the material and thus improving the DC superposition performance of the material; and by adding mixed rare earth alloys as nucleating agents, heterogeneous nucleation preforms are provided to increase the grain size of the atomized powder and improve the sphericity of the powder.

[0007] Based on the above problems, this invention proposes a solution that improves the DC superposition performance of iron-silicon-aluminum magnetic powder cores.

[0008] As a preferred technical solution, the chemical composition of the iron-silicon-aluminum alloy is 5 wt.% silicon, 3 wt.% aluminum, 1.5 wt.% nickel, 0.5 wt.% cobalt, and 90 wt.% iron.

[0009] As a preferred technical solution, the amount of mixed rare earth added is 0.2 wt.% of the total amount of silicon, aluminum, nickel, cobalt and iron.

[0010] As a preferred technical solution, the chemical composition of the mixed rare earth alloy is: lanthanum 20-30 wt.%, yttrium 10-20 wt.%, manganese 30-40 wt.%, with the balance being iron.

[0011] As a further preferred technical solution, the chemical composition of the mixed rare earth alloy is: lanthanum 25 wt.%, yttrium 20 wt.%, manganese 40 wt.%, and iron 15 wt.%.

[0012] As a preferred technical solution, the amount of carbon sheet added is 0.5 wt.% of the total amount of silicon, aluminum, nickel, cobalt and iron; the carbon content of the carbon sheet is greater than 99.9 wt.%.

[0013] This application adds carbon sheets in the later stage of smelting to reduce the content of gaseous impurities such as oxygen and nitrogen in the molten pool and reduce the coercivity of the soft magnetic powder; it also adds an appropriate amount of mixed rare earth alloy to simultaneously provide heterogeneous nucleation preforms, increase the grain size of the atomized powder, and improve the sphericity of the powder, thereby improving the DC superposition performance of the iron-silicon-aluminum magnetic powder core.

[0014] It should be noted that a vacuum pump needs to be turned on during smelting, and carbon powder can easily be drawn outside the melting chamber, causing material loss. Therefore, this application adds carbon in the form of carbon sheets, which are less likely to be drawn outside the melting chamber. The carbon sheets added in this invention are also called graphite carbon sheets, with a carbon content greater than 99.9 wt.%, for example, they can be carbon sheets purchased from Gansu Haoshi Carbon Fiber Co., Ltd., brand name GSK. The embodiments described later in this invention use such carbon sheets.

[0015] During vacuum smelting, carbon combines with the metal and oxygen in the molten pool to form carbon-oxygen gas, which is then pumped out of the melt by a vacuum pump. Therefore, carbon hardly enters the interior of the alloy product. The addition of mixed rare earth alloys is minimal (preferably only about 0.2 wt.% of the total alloy). Its main function is as a heterogeneous nucleating agent to increase grain size and reduce coercivity. Additionally, some rare earth alloys combine with carbon and oxygen and are also pumped out of the melt by the vacuum pump.

[0016] As a preferred technical solution, the specific steps include:

[0017] (1) Place industrial pure iron, electrolytic nickel, cobalt and silicon blocks in a crucible according to the proportions, then start to evacuate the vacuum. When the vacuum degree is less than 10 Pa, fill with nitrogen and start to energize for induction melting.

[0018] (2) After the pure iron and electrolytic nickel are melted, aluminum blocks, carbon sheets and mixed rare earth alloys are added, and the vacuum pump is turned on at the same time to reduce the vacuum to below 2 Pa.

[0019] (3) After the temperature of the molten pool rises to 1650℃, pour the molten pool into the preheated intermediate ladle crucible and start atomization under nitrogen pressure of 4 MPa;

[0020] (4) After vacuum atomization, the obtained iron-silicon-aluminum soft magnetic alloy powder is sieved and the powder passing through 200 mesh is obtained.

[0021] The second objective of this invention is to provide a high DC superposition performance iron-silicon-aluminum soft magnetic alloy prepared by the above method.

[0022] The third objective of this invention is to provide applications of the aforementioned high DC superposition performance iron-silicon-aluminum soft magnetic alloy. The technical solution adopted is to mix the obtained iron-silicon-aluminum soft magnetic alloy with organosilicon resin and press it into a magnetic powder core for use in power electronic components in high-power, high-current applications.

[0023] As a preferred technical solution, power electronic components include, but are not limited to, inverter inductors, energy storage inductors, and power correction factor inductors.

[0024] The application method can be as follows: 100g of iron-silicon-aluminum powder prepared by vacuum atomization and 2g of organosilicon resin are stirred in 10 mL of acetone solution until dry, and then pressed into a ring (outer diameter 12.7mm, inner diameter 7.6mm, height 4.5mm) under 2000MPa. The pressed ring is placed in a tube furnace and heated to 750℃ at a rate of 5℃ / min under an argon atmosphere, held at that temperature for 1 h, and then cooled to room temperature with the furnace. 25 turns of primary coil and 25 turns of secondary coil are uniformly wound onto the heat-treated iron-silicon-aluminum magnetic ring using 0.5mm enameled wire, and then DC superposition performance testing can be performed. The DC superposition performance test is conducted using a Japanese Iwasaki SY-8218 BH tester.

[0025] Preferably, the silicone resin is a common methylated silicone resin.

[0026] This invention improves the DC superposition performance of iron-silicon-aluminum powder cores by optimizing the chemical composition of traditional iron-silicon-aluminum alloys (Fe-9.6Si-5.4Al) during induction melting, thereby increasing the proportion of ferromagnetic elements and the saturation magnetic flux density. By adding appropriate amounts of the ferromagnetic elements nickel and cobalt, this invention reduces the magnetocrystalline anisotropy constant and saturation magnetostriction coefficient of the iron-silicon-aluminum alloy without causing a significant decrease in saturation magnetic flux density. The minimum proportion of ferromagnetic elements in the iron-silicon-aluminum alloy of this invention is 89 wt.%, which is still higher than that of traditional iron-silicon-aluminum alloys (ferromagnetic element proportion is 85 wt.%). Simultaneously, this invention incorporates carbon sheets and mixed rare-earth alloys during vacuum induction melting to reduce the content of gaseous impurities such as oxygen and nitrogen in the molten pool. The manganese element in the carbon sheets and mixed rare-earth alloys of this invention forms volatile gaseous compounds (such as carbon dioxide and manganese oxide) with oxygen inside the molten pool, which are then extracted from the melting chamber using a vacuum pump, thereby reducing the content of gaseous impurities inside the molten pool. Lanthanum and yttrium in the mixed rare earth alloys serve as the preforms during the atomization and crystallization of the novel iron-silicon-aluminum alloy, increasing the grain growth rate, optimizing the micro-grain size and macro-sphericity of the powder, and thus further improving the soft magnetic properties of the novel iron-silicon-aluminum alloy.

[0027] The novel iron-silicon-aluminum metal powder with high magnetic flux density, low impurity content, large grain size, and high sphericity prepared by the method of the present invention can improve the DC superposition performance of iron-silicon-aluminum magnetic powder cores, and meet their application in power electronic components in high-power and high-current applications, such as inverter inductors and energy storage inductors.

[0028] Compared with the prior art, the advantages of the present invention are: the novel iron-silicon-aluminum metal powder prepared by the present invention can significantly improve the DC superposition performance of iron-silicon-aluminum magnetic powder core products, and meet the requirements of magnetic components to withstand large current and high power. Attached Figure Description

[0029] Figure 1 This is a comparison chart of the oxygen content of the novel iron-silicon-aluminum powder (a) prepared in Example 1 of the present invention and the traditional iron-silicon-aluminum (Fe-9.6Si-5.4Al) powder (b);

[0030] Figure 2 This is a scanning electron microscope image of the novel iron-silicon-aluminum metal powder prepared in Example 1 of the present invention.

[0031] Figure 3 The DC superposition performance diagram of the iron-silicon-aluminum magnetic powder core sample prepared in Application Example 1 of this invention;

[0032] Figure 4 The DC superposition performance diagram of a traditional iron-silicon-aluminum (Fe-9.6Si-5.4Al) magnetic powder core;

[0033] Figure 5 The image shows the microscopic scanning electron microscope (SEM) morphology of the iron-silicon-aluminum metal powder prepared in Example 4 for comparison. Implementation

[0034] The invention will now be further described with reference to the accompanying drawings.

[0035] Example 1

[0036] (1) Weigh high-purity silicon (Si > 98.5 wt.%), aluminum blocks, electrolytic nickel, cobalt and industrial pure iron in proportions of Si 3 wt.%, Al 3 wt.%, nickel 1 wt.%, Co 0.5 wt.% and Fe 92.5 wt.%, respectively, for a total of 15 Kg; based on the total weight of the alloy (15 Kg), weigh 0.075 Kg of carbon sheet and 0.03 Kg of mixed rare earth alloy; the chemical composition of the mixed rare earth alloy is: lanthanum 30 wt.%, yttrium 20 wt.%, manganese 40 wt.%, with the balance being iron;

[0037] First, industrial pure iron, electrolytic nickel, metallic cobalt, and silicon ingots are placed in a crucible. A vacuum is then drawn until the vacuum level is less than 10 Pa. Nitrogen gas is then introduced, and induction melting is initiated. After the added metals melt, aluminum ingots, carbon sheets, and rare earth alloys are added using a secondary feeding device. Simultaneously, the vacuum pump is restarted, and the vacuum level is reduced to below 2 Pa. Once the molten pool temperature reaches 1650℃, the molten pool is poured into a preheated intermediate ladle crucible, and atomization begins under a nitrogen pressure of 4 MPa. After vacuum atomization, the resulting novel iron-silicon-aluminum soft magnetic alloy powder is sieved, and powder passing through a 200-mesh sieve is used as the raw material for preparing magnetic powder cores.

[0038] Figure 1A comparison of oxygen and nitrogen impurity content between a novel iron-silicon-aluminum metal powder prepared by vacuum atomization with added carbon flakes and rare earth alloys, and a traditional iron-silicon-aluminum powder prepared by a certain manufacturer using the same vacuum atomization method. Oxygen impurity content was measured using an oxygen-nitrogen analyzer (ON-3000, Steel Research Institute Nake). Figure 1 It can be seen that the oxygen and nitrogen contents of the novel iron-silicon-aluminum powder prepared in this embodiment are 680 ppm and 451 ppm, respectively, which are significantly lower than the oxygen and nitrogen contents of traditional iron-silicon-aluminum metal powder (980 ppm oxygen and 525 ppm nitrogen).

[0039] from Figure 2 As can be seen from the present invention, the powder prepared by the method has high sphericity and uniform grain size, which is one of the conditions for obtaining excellent DC superposition performance.

[0040] Application Example 1

[0041] 100g of the iron-silicon-aluminum powder prepared in Example 1 was randomly weighed, 2g of silicone resin (Zhongshan Kebang Chemical Co., Ltd.) was added, and then 10 mL of acetone solution was added and stirred until dry. The mixture was then passed through a 40-mesh sieve, and an appropriate amount of release agent was added. 2.2g of granulated powder was pressed into rings (outer diameter 12.7mm, inner diameter 7.6mm, height 4.5mm) under a pressure of 2000 MPa, and heated to 750℃ in a tube at a rate of 10℃ / min under an argon atmosphere, held at that temperature for 1 h, and then cooled to room temperature in the furnace.

[0042] Comparative Application Example 1

[0043] The preparation method is basically the same as that in Application Example 1, except that 100g of traditional iron-silicon-aluminum powder prepared by vacuum atomization method from a certain manufacturer is selected.

[0044] Test Example 1

[0045] The magnetic powder cores prepared from the two different iron-silicon-aluminum metal powders were uniformly wound with 25 turns of primary coil and 25 turns of secondary coil using 0.5 mm enameled wire, respectively, and their DC superposition performance was tested using a Japanese Iwasaki SY-8218 BH tester. Figure 3 The novel iron-silicon-aluminum magnetic powder core sample prepared in Example 1 is shown. Figure 4 A comparison diagram showing the DC superposition performance of conventional iron-silicon-aluminum (Fe-9.6Si-5.4Al) magnetic powder cores prepared in Application Example 1. (From...) Figure 3 and Figure 4The comparison shows that the 60μm novel iron-silicon-aluminum powder prepared in this invention retains 62.1% of its permeability under a DC magnetic field of 100 Oe, which is significantly better than that of traditional iron-silicon-aluminum (Fe-9.6Si-5.4Al) magnetic powder cores (only 47.6%). This indicates that the novel iron-silicon-aluminum soft magnetic metal powder prepared by this invention produces iron-silicon-aluminum magnetic powder cores with excellent DC superposition performance, which lays a solid foundation for the application of iron-silicon-aluminum electronic components under high current and high power conditions.

[0046] Example 2

[0047] (1) Weigh high-purity silicon, aluminum blocks, electrolytic nickel, cobalt, and industrial pure iron according to the following proportions: Si 6wt.%, Al 5wt.%, Nickel 3wt.%, Co 1wt.%, and Fe 85wt.%, respectively, for a total weight of 15 kg. Weigh 0.075 kg of carbon sheets and 0.03 kg of mixed rare earth alloy based on the total weight of the alloy. The chemical composition of the mixed rare earth alloy is: lanthanum 20wt.%, yttrium 10wt.%, manganese 30wt.%, with the balance being iron.

[0048] (2) First, industrial pure iron, electrolytic nickel, metallic cobalt, and silicon blocks are placed in a crucible, and then a vacuum is drawn. When the vacuum degree is less than 10 Pa, nitrogen is introduced and induction melting is started. After the added metals melt, aluminum blocks, carbon sheets, and rare earth alloys are added using a secondary feeding device. At the same time, the vacuum pump is turned on again to draw the vacuum degree to below 2 Pa. After the temperature of the molten pool rises to 1650 ℃, the molten pool is poured into a preheated intermediate ladle crucible and atomized under a nitrogen pressure of 4 MPa. After the vacuum atomization is completed, the obtained novel iron-silicon-aluminum soft magnetic alloy powder is sieved, and the powder passing through 200 mesh is used as the raw material for preparing magnetic powder cores.

[0049] Application Example 2

[0050] 100g of the iron-silicon-aluminum powder prepared in Example 2 was randomly weighed, 2g of silicone resin (Zhongshan Kebang Chemical Co., Ltd.) was added, and then 10 mL of acetone solution was added and stirred until dry. The mixture was then passed through a 40-mesh sieve, and an appropriate amount of release agent was added. 2.2g of granulated powder was pressed into rings (outer diameter 12.7mm, inner diameter 7.6mm, height 4.5mm) under a pressure of 2000 MPa, and heated to 750℃ in a tube at a rate of 10℃ / min under an argon atmosphere, held at that temperature for 1 h, and then cooled to room temperature in the furnace.

[0051] Test Example 2

[0052] The magnetic powder core prepared in Application Example 2 was used to uniformly wind 25 turns of primary coil and 25 turns of secondary coil using 0.5 mm enameled wire. The DC superposition performance was tested using a BH tester (SY-8218 type) from Iwasaki, Japan. The 60μm novel iron-silicon-aluminum core prepared in Application Example 2 maintained a permeability of 60.9% under a 100 Oe DC magnetic field, which is significantly better than the traditional iron-silicon-aluminum (Fe-9.6Si-5.4Al) magnetic powder core (only 47.6%).

[0053] Example 3

[0054] High-purity silicon, aluminum blocks, electrolytic nickel, cobalt, and industrial pure iron were weighed according to the following proportions: Si 5 wt.%, Al 4 wt.%, Nickel 2 wt.%, Co 0.8 wt.%, and Fe 88.2 wt.%, totaling 15 kg. Based on the total weight of the alloy, 0.075 kg of carbon sheets and 0.03 kg of mixed rare earth alloy were weighed. The chemical composition of the mixed rare earth alloy was: lanthanum 20 wt.%, yttrium 10 wt.%, manganese 30 wt.%, with the balance being iron.

[0055] (2) First, industrial pure iron, electrolytic nickel, metallic cobalt, and silicon blocks are placed in a crucible, and then a vacuum is drawn. When the vacuum degree is less than 10 Pa, nitrogen is introduced and induction melting is started. After the added metals melt, aluminum blocks, carbon sheets, and rare earth alloys are added using a secondary feeding device. At the same time, the vacuum pump is turned on again to draw the vacuum degree to below 2 Pa. After the temperature of the molten pool rises to 1650 ℃, the molten pool is poured into a preheated intermediate ladle crucible and atomized under a nitrogen pressure of 4 MPa. After vacuum atomization, the obtained novel iron-silicon-aluminum soft magnetic alloy powder is sieved, and the powder passing through 200 mesh is used as the raw material for preparing magnetic powder cores.

[0056] Application Example 3

[0057] 100g of the iron-silicon-aluminum powder prepared in Example 3 was randomly weighed, 2g of silicone resin (Zhongshan Kebang Chemical Co., Ltd.) was added, and then 10 mL of acetone solution was added and stirred until dry. The mixture was then passed through a 40-mesh sieve, and an appropriate amount of release agent was added. 2.2g of granulated powder was pressed into rings (outer diameter 12.7mm, inner diameter 7.6mm, height 4.5mm) under a pressure of 2000 MPa, and heated to 750℃ in a tube at a rate of 10℃ / min under an argon atmosphere, held at that temperature for 1 h, and then cooled to room temperature in the furnace.

[0058] Test Example 3

[0059] The magnetic powder core prepared in Application Example 3 was wound with 25 turns of primary coil and 25 turns of secondary coil using 0.5 mm enameled wire, respectively. DC superposition performance was tested using a BH tester (SY-8218 type) from Iwasaki, Japan. The 60μm novel iron-silicon-aluminum (Fe-9.6Si-5.4Al) magnetic powder core prepared in Application Example 3 maintained a permeability of 61.8% under a 100 Oe DC magnetic field, significantly better than the traditional Fe-9.6Si-5.4Al (Fe-9.6Si-5.4Al) magnetic powder core (only 47.6%). This demonstrates that the novel Fe-9.6Si-5.4Al soft magnetic metal powder prepared using this invention produces a magnetic powder core with excellent DC superposition performance, laying a solid foundation for the application of Fe-9.6Si-5.4Al electronic components under high current and high power conditions.

[0060] Example 4

[0061] (1) Weigh high-purity silicon (Si > 98.5 wt.%), aluminum blocks, electrolytic nickel, cobalt and industrial pure iron according to the proportions of Si 5 wt.%, Al 5 wt.%, nickel 1.5 wt.%, Co 0.5 wt.% and Fe 90 wt.%, respectively, for a total of 15 Kg; based on the total weight of the alloy, weigh 0.075 Kg of carbon sheet and 0.03 Kg of mixed rare earth alloy; the chemical composition of the mixed rare earth alloy is: lanthanum content 25 wt.%, yttrium content 20 wt.%, manganese content 40 wt.%, and the balance is iron;

[0062] First, industrial pure iron, electrolytic nickel, metallic cobalt, and silicon ingots are placed in a crucible. A vacuum is then drawn until the vacuum level is less than 10 Pa. Nitrogen gas is then introduced, and induction melting is initiated. After the added metals melt, aluminum ingots, carbon sheets, and rare earth alloys are added using a secondary feeding device. Simultaneously, the vacuum pump is restarted, and the vacuum level is reduced to below 2 Pa. Once the molten pool temperature reaches 1650℃, the molten pool is poured into a preheated intermediate ladle crucible, and atomization begins under a nitrogen pressure of 4 MPa. After vacuum atomization, the resulting novel iron-silicon-aluminum soft magnetic alloy powder is sieved, and powder passing through a 200-mesh sieve is used as the raw material for preparing magnetic powder cores.

[0063] Comparative Example 4

[0064] The preparation method is basically the same as in Example 4, except that carbon flakes and mixed rare earth alloys are not added during induction melting. Test results from an oxygen and nitrogen analyzer (ON-3000, NAK Steel Research Institute) showed that the oxygen and nitrogen contents in the iron-silicon-aluminum metal powder prepared without the addition of carbon flakes and rare earth alloys were 945 ppm and 498 ppm, respectively. The comparison shows that adding carbon flakes and mixed rare earth alloys can reduce the oxygen and nitrogen impurity content in the iron-silicon-aluminum metal powder. Figure 5 The metal powder morphology photographs prepared in Example 4 show that the metal powder prepared without adding carbon sheets and mixed rare earth alloys has poor sphericity and small grain size.

[0065] Application Example 4

[0066] 100g of the iron-silicon-aluminum powder prepared in Example 4 was randomly weighed, 2g of silicone resin (Zhongshan Kebang Chemical Co., Ltd.) was added, and then 10 mL of acetone solution was added and stirred until dry. The mixture was then passed through a 40-mesh sieve, and an appropriate amount of release agent was added. 2.2g of granulated powder was pressed into rings (outer diameter 12.7mm, inner diameter 7.6mm, height 4.5mm) under a pressure of 2000 MPa, and heated to 750℃ in a tube at a rate of 10℃ / min under an argon atmosphere, held at that temperature for 1 h, and then cooled to room temperature in the furnace.

[0067] Comparative Application Example 4

[0068] The preparation method is basically the same as that of Application Example 4, except that the iron-silicon-aluminum powder prepared in Comparative Example 4 is selected.

[0069] Test Example 4

[0070] The magnetic powder cores prepared from the two different iron-silicon-aluminum metal powders were uniformly wound with 25 turns of primary coil and 25 turns of secondary coil using 0.5 mm enameled wire, respectively. DC superposition performance tests were conducted using a Japanese Iwasaki SY-8218 BH tester. The 60μm novel iron-silicon-aluminum core prepared in Application Example 4 exhibited a permeability retention of 62.5% under a 100 Oe DC magnetic field, which is significantly better than the iron-silicon-aluminum core prepared in Comparative Example 4 (only 54.6%).

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high DC superposition performance iron-silicon-aluminum soft magnetic alloy, characterized in that, The method is a vacuum atomization method, and the raw materials used are silicon 3-6 wt.%, aluminum 3-5 wt.%, nickel 1-3 wt.%, cobalt 0.5-1 wt.%, with the balance being iron, totaling 100 wt.%; mixed rare earth alloys and carbon sheets are also added during vacuum refining; The amount of the mixed rare earth alloy added is 0.2 wt.% of the total amount of silicon, aluminum, nickel, cobalt, and iron. The chemical composition of the mixed rare earth alloy is: lanthanum 20-30 wt.%, yttrium 10-20 wt.%, manganese 30-40 wt.%, with the balance being iron; The amount of carbon sheet added is 0.5 wt.% of the total amount of silicon, aluminum, nickel, cobalt, and iron. The total content of nickel, cobalt and iron is ≥89 wt.%.

2. The method of producing high direct current superposed performance iron-silicon-aluminum soft magnetic alloy according to claim 1, characterized by, The raw materials used are 5 wt.% silicon, 3 wt.% aluminum, 1.5 wt.% nickel, 0.5 wt.% cobalt, and 90 wt.% iron.

3. The method of producing high direct current superposed performance iron-silicon-aluminum soft magnetic alloy according to claim 1, characterized by, The chemical composition of the mixed rare earth alloy is: lanthanum 25 wt.%, yttrium 20 wt.%, manganese 40 wt.%, and iron 15 wt.%.

4. The method of producing high direct current superposed performance iron-silicon-aluminum soft magnetic alloy according to claim 1, characterized by, The carbon sheet has a C content greater than 99.9 wt.%.

5. The method of claim 1, wherein the Fe-Si-Al soft magnetic alloy has a high direct current superposition performance. The specific steps include: (1) Place industrial pure iron, electrolytic nickel, cobalt and silicon blocks in a crucible according to the proportions, then start to evacuate the vacuum. When the vacuum degree is less than 10 Pa, fill with nitrogen and start to energize for induction melting. (2) After the pure iron and electrolytic nickel are melted, aluminum blocks, carbon sheets and mixed rare earth alloys are added, and the vacuum pump is turned on at the same time to reduce the vacuum to below 2 Pa. (3) After the temperature of the molten pool rises to 1650℃, pour the molten pool into the preheated intermediate ladle crucible and start atomization under nitrogen pressure of 4MPa; (4) After vacuum atomization, the obtained iron-silicon-aluminum soft magnetic alloy powder is sieved to obtain the final product.

6. The high DC superposition performance iron-silicon-aluminum soft magnetic alloy prepared by the method of any one of claims 1 to 5.

7. Use of the high DC superposed performance Fe-Si-Al soft magnetic alloy produced by the method according to any one of claims 1 to 5, characterized in that, The obtained iron-silicon-aluminum soft magnetic alloy is mixed with organosilicon resin and pressed into magnetic powder cores, which are then used in power electronic components for high-power, high-current applications.

8. The application according to claim 7, characterized in that, Power electronic components include inverter inductors, energy storage inductors, and power correction factor inductors.

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