A method of undercooled solidification for preparing an amorphous nanocrystalline soft magnetic alloy with a high Fe content

Abstract

The present invention provides a supercooled solidification method for preparing a high-Fe-content amorphous nanocrystalline soft magnetic alloy and a suitable amorphous nanocrystalline composition. The supercooled solidification is achieved by glass purification combined with cyclic superheating or electromagnetic levitation melting. The supercooled solidified alloy is then rapidly quenched or atomized from the melt to form an amorphous ribbon or powder, which can then be heat treated to form a nanocrystalline alloy. The applicable amorphous nanocrystalline chemical formula is FeSiBM, characterized in that M is one or more of P, C, Nb, Mo, Zr, Hf, Mo, Y, Cu, and Co, the total atomic percentage of each alloying element is 100%, and the following element contents are satisfied: Fe is 80.0-89.0 at%, Si is 1.0-9.0 at%, B is 3.0-12.0 at%, P is 0-5.0 at%, C is 0-5.0 at%, Nb is 0-3.0 at%, Zr is 0-3.0 at%, Hf is 0-3.0 at%, Mo is 0-3.0 at%, Y is 0-5.0 at%, Cu is 0-2.0 at%, and Co is 0-16.0 at%. The amorphous nanocrystalline alloy prepared by supercooled non-equilibrium solidification has high amorphous forming ability, high saturation magnetization, and low coercive force.

Description

Technical Field

[0001] The invention relates to a method for preparing an amorphous nanocrystalline soft magnetic alloy with a high Fe content through supercooling and solidification, and belongs to the field of metallic soft magnetic materials. Background Art

[0002] Due to their unique microstructure, Fe-based amorphous and nanocrystalline soft magnetic alloys have significant advantages over crystalline soft magnetic alloys, such as low coercivity and high resistivity. However, the presence of a large amount of amorphous elements in Fe-based amorphous and nanocrystalline alloys reduces the saturation magnetization intensity, limiting the high-power and miniaturization development of related soft magnetic devices. The saturation magnetization intensity of classic amorphous soft magnetic alloys (international brand Metglas 2605SA1, domestic brand 1K101) is about 1.55T, while the saturation magnetization intensity of classic nanocrystalline soft magnetic alloys (international brand Finemet, domestic brand 1K107) is about 1.24T, both of which are far lower than the saturation magnetization intensity of silicon steel (about 2.12T).

[0003] In order to fully realize the application potential of amorphous nanocrystalline soft magnetic alloys in various power electronic devices, it is urgent to increase the content of magnetic elements, mainly Fe, and the saturation magnetization intensity in Fe-based amorphous nanocrystalline alloys. The challenge in preparing high-Fe content amorphous nanocrystalline soft magnetic alloys is that the requirements for obtaining an amorphous matrix are relatively stringent, and the cooling rate of the molten alloy needs to reach about 10 5 ℃ / s or more. According to the Inoue amorphous principle, alloys often require the addition of approximately 20 at% of nonmagnetic elements to promote the formation of an amorphous structure. Nanocrystalline soft magnetic alloys, formed by crystallization and annealing of amorphous alloys, often require the addition of nonmagnetic elements to nucleate and inhibit grain growth. The introduction of these elements significantly limits the content of ferromagnetic elements in amorphous and nanocrystalline soft magnetic alloys, making it difficult to achieve high saturation magnetization.

[0004] At present, the methods for improving the saturation magnetization of Fe-based amorphous nanocrystalline soft magnetic alloys mainly focus on composition control. One is to enhance the ferromagnetic exchange strength of the alloy by adding Co elements to improve the saturation magnetization of the alloy. For example, Patent ZL201410728540.1 discloses a Fe a Co b Nb c B d Cu e The alloy is made by adding 6-20at% Co to increase the saturation magnetization of the nanocrystalline alloy to 1.80T, and the coercivity is in the range of 10-35A / m. The second is to adjust the addition amount of metal elements such as Si, B, C, and P. For example, Patent ZL200510066862.5 discloses a Fe a Si b B c C dAlloy, when c is in the range of 12 to 18 at%, and satisfies b≤(0.5×a-36)×d 1 / 3 Under the given conditions, the saturation magnetization intensity of the iron-based amorphous strip can reach above 1.60 T. In addition, ZL201410285976.8 discloses a Fe a Si b B c C d P e Alloy, by adjusting the proportion of metal elements added, Fe 84.3 Si 2.3 B 9.7 C 0.9 P 2.8 The alloy has the highest saturation magnetization of 1.69 T. On the one hand, this type of method is based on the Inoue amorphous principle, adjusting the proportion of metalloid addition to affect the alloy mixing enthalpy and atomic size differences, so as to improve the alloy's amorphous forming ability and thereby increase the content of ferromagnetic elements; on the other hand, since the 2p electrons of the metalloid elements can affect the 3d electrons of Fe, the size of the Fe atomic magnetic moment is affected, thereby regulating the alloy's saturation magnetization. It can be seen from the above patents that by adjusting the content of metalloid elements, it is necessary to precisely control the ratio of different elements, and the increase in the amount of ferromagnetic elements added is still limited, which limits the further improvement of the saturation magnetization.

[0005] This patent achieves supercooling solidification of Fe-based amorphous nanocrystalline alloys through glass purification combined with cyclic overheating or electromagnetic suspension melting, reducing the amount of non-magnetic elements added to the alloy, effectively increasing the amount of ferromagnetic elements added to the alloy, increasing the alloy's saturation magnetization and maintaining low coercivity. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the existing Fe-based amorphous nanocrystalline soft magnetic alloy preparation technology. By using a supercooled non-equilibrium solidification method, the amount of amorphous-forming elements added to the alloy is reduced, thereby achieving the preparation of a high-Fe content amorphous nanocrystalline soft magnetic alloy, thereby broadening the design range of the Fe-based amorphous nanocrystalline soft magnetic alloy composition and improving the alloy's saturation magnetization strength.

[0007] The present invention is achieved through the following technical solutions:

[0008] A supercooling solidification method for preparing a high-Fe content amorphous nanocrystalline soft magnetic alloy adopts a method of molten glass purification combined with cyclic overheating or electromagnetic levitation melting to supercool the alloy and reduce the amount of amorphous-forming elements added to the Fe-based amorphous nanocrystalline soft magnetic alloy, thereby increasing the proportion of Fe elements and achieving the goal of increasing the saturation magnetization intensity and reducing the coercive force.

[0009] Preferably, the method for purifying molten glass in combination with cyclic superheating comprises the following steps:

[0010] In the first step, the chemical formula of the amorphous nanocrystalline alloy is FeSiBM, where M is one or more elements selected from P, C, Nb, Mo, Zr, Hf, Mo, Y, Cu, and Co. After removing the oxide scale from the alloy raw materials and cleaning them, the raw materials are weighed according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace or a vacuum arc melting furnace and vacuumed to at least 10 -3 After Pa, fill with inert gas protection for smelting, and repeat smelting 4 to 6 times to obtain alloy ingots;

[0011] The second step is to place the alloy ingot into the crucible and cover the upper and lower surfaces of the crucible with a glass purifier of a certain mass ratio so that the glass purifier completely covers the alloy ingot;

[0012] The third step is to vacuum to at least 10 -2 After Pa, fill with inert gas protection and heat the alloy until it melts, then raise the temperature to 1200-1500℃, keep warm for 1-10 minutes, turn off the heating power, and let the alloy cool naturally;

[0013] The fourth step is to perform a "heating-holding-solidification" cycle 3 to 6 times to obtain the required undercooling degree of the alloy;

[0014] The fifth step is to solidify the supercooled solidified alloy into a strip or powder by rapid quenching or atomization of the melt;

[0015] In the sixth step, the obtained strip or powder is subjected to stress relief annealing to obtain an Fe-based amorphous alloy, or is subjected to crystallization annealing to obtain an Fe-based nanocrystalline alloy.

[0016] Preferably, the inert gas is argon or nitrogen with a purity of not less than 99.9 vol%.

[0017] Preferably, the crucible has a heat-resistant temperature of not less than 1400°C.

[0018] Preferably, the method for preparing a high-Fe-content amorphous nanocrystalline soft magnetic alloy by purifying molten glass and combining it with cyclic overheating is characterized in that the glass purifier preparation process includes: weighing powdered Na2B4O7 and B2O3 with a purity of not less than 98%, placing them separately in a high-purity corundum crucible, firing them at 400-600°C for 1-8 hours, and then melting and firing them at 800-1000°C for 2-16 hours. The fired Na2B4O7 and B2O3 are mixed to obtain a purifier, with a mass ratio of 1:1-20.

[0019] Preferably, the mass ratio of the glass purifier to the alloy ingot is 1:1-5.

[0020] Preferably, the electromagnetic levitation smelting method comprises the following steps:

[0021] In the first step, the chemical formula of the amorphous nanocrystalline alloy is FeSiBM, where M is one or more elements selected from P, C, Nb, Mo, Zr, Hf, Mo, Y, Cu, and Co. After removing the oxide scale from the alloy raw materials and cleaning them, the raw materials are weighed according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace or a vacuum arc melting furnace and vacuumed to at least 10 -3 After Pa, fill with inert gas protection for smelting, and repeat smelting 4 to 6 times to obtain alloy ingots;

[0022] The second step is to vacuum to at least 10 -3 After Pa, the inert gas is filled for protection, and the alloy ingot is sent to the bottom of the suspension coil. The mother alloy is stably suspended at the center of the heating coil by the Lorentz force formed by the interaction between the electromagnetic field and the induced current.

[0023] The third step is to use the heating coil to induction heat the alloy until it melts, then raise the temperature to 1200-1500°C and keep it warm for 1-10 minutes. After that, turn off the heating power and let the alloy cool naturally.

[0024] The fourth step is to perform a "heating-holding-solidification" cycle 3 to 6 times to obtain the required undercooling degree of the alloy;

[0025] The fifth step is to solidify the supercooled solidified alloy into a strip or powder by rapid quenching or atomization of the melt;

[0026] In the sixth step, the obtained strip or powder is subjected to stress relief annealing to obtain an Fe-based amorphous alloy, or is subjected to crystallization annealing to obtain an Fe-based nanocrystalline alloy.

[0027] Preferably, the chemical expression of the high Fe content amorphous nanocrystalline soft magnetic alloy is FeSiBM, characterized in that M is one or more elements selected from P, C, Nb, Mo, Zr, Hf, Mo, Y, Cu, and Co, the total atomic percentage of each alloying element is 100%, and the following element contents are satisfied: Fe is 80.0-89.0at%, Si is 1.0-9.0at%, B is 3.0-12.0at%, P is 0-5.0at%, C is 0-5.0at%, Nb is 0-3.0at%, Zr is 0-3.0at%, Hf is 0-3.0at%, Mo is 0-3.0at%, Y is 0-5.0at%, Cu is 0-2.0at%, and Co is 0-16.0at%.

[0028] Preferably, the inert gas is argon or nitrogen with a purity of not less than 99.9 vol%.

[0029] Preferably, the amorphous alloy is annealed in a temperature range of 50 to 100° C. below the crystallization temperature, and the nanocrystalline alloy is annealed in a temperature range of 0 to 100° C. above the crystallization temperature.

[0030] Preferably, the annealing is carried out in an inert gas atmosphere or a vacuum degree greater than 10 -1 Pa environment.

[0031] The amorphous and nanocrystalline soft magnetic alloys prepared using the nonequilibrium solidification method described above have high glass-forming ability, which helps reduce the amount of glass-forming elements added to the alloy and increase the content of the ferromagnetic element Fe. The high-Fe content amorphous and nanocrystalline alloys prepared using this method exhibit soft magnetic properties with high saturation magnetization and low coercivity. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below. By regulating the alloy composition and supercooling, a high Fe content amorphous nanocrystalline soft magnetic alloy with high saturation magnetization is obtained.

[0033] Example 1

[0034] Preparation of FeSiB Amorphous Alloy by Supercooling Solidification

[0035] FeSiB system alloys were prepared, wherein the Fe content in alloy 1 was 83.0 at%, the Si content was 8.0 at%, and the B content was 9.0 at%; the Fe content in alloy 2 was 85.0 at%, the Si content was 7.0 at%, and the B content was 8.0 at%; and the Fe content in alloy 3 was 88.0 at%, the Si content was 3.0 at%, and the B content was 9.0 at%;

[0036] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, fill with 99.9vol% purity argon gas for protection and carry out smelting, and repeat the smelting for 5 times to obtain the alloy ingot;

[0037] The second step is to place the alloy ingot into a crucible and cover the upper and lower surfaces of the crucible with a mixture of purified glass of Na2B4O7 and B2O3, with a mass ratio of 1:5, so that the glass purifier completely covers the alloy ingot.

[0038] The third step is to vacuum up to 5×10 -3 After the temperature reaches 5000 Pa, the alloy is heated to molten state by argon gas with a purity of 99.9 vol%. The temperature is then raised to 1350 °C and kept at this temperature for 2 minutes. The heating power is then turned off and the alloy is allowed to cool naturally.

[0039] In the fourth step, the “heating-holding-solidification” cycle was performed 4 and 6 times respectively, so that the alloys achieved undercooling of about 190°C and 260°C;

[0040] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0041] Step 6: stress relief annealing the obtained strip at 300°C to obtain an Fe-based amorphous alloy;

[0042] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0043] Table 1 Saturation magnetization and coercivity of FeSiB amorphous alloys with different undercooling degrees

[0044]

[0045]

[0046] Example 2

[0047] Preparation of FeSiBPC Amorphous Alloy by Supercooling Solidification

[0048] FeSiBPC system alloys were prepared, wherein alloy 1 had an Fe content of 84.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, a P content of 5.0 at%, and a C content of 1.0 at%; alloy 2 had an Fe content of 84.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, a P content of 1.0 at%, and a C content of 5.0 at%; and alloy 3 had an Fe content of 89.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, a P content of 0.5 at%, and a C content of 0.5 at%;

[0049] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum arc melting furnace and vacuumed to 7×10 -4 After Pa, fill with 99.9vol% nitrogen protection for smelting, and repeat smelting 6 times to obtain alloy ingots;

[0050] The second step is to place the alloy ingot into a crucible and cover its upper and lower surfaces with a mixture of purified glass of Na2B4O7 and B2O3 in a mass ratio of 1:4, so that the glass purifier completely covers the alloy ingot;

[0051] The third step is to vacuum up to 4×10 -3 After Pa, fill with 99.9 vol% nitrogen gas and heat the alloy until it melts, then raise the temperature to 1400 ° C, keep it at this temperature for 3 minutes, turn off the heating power, and let the alloy cool naturally;

[0052] In the fourth step, the “heating-holding-solidification” cycle was performed 4 and 6 times respectively, so that the alloys achieved undercooling of about 160°C and 255°C;

[0053] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0054] Step 6: stress relief annealing the obtained strip at 300°C to obtain an Fe-based amorphous alloy;

[0055] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0056] Table 2 Saturation magnetization and coercivity of FeSiBPC amorphous alloys with different undercooling degrees

[0057]

[0058] Example 3

[0059] Preparation of FeSiBC Amorphous Alloy by Supercooling Solidification

[0060] FeSiBC system alloys were prepared, wherein alloy 1 had an Fe content of 84.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, and a C content of 6.0 at%; alloy 2 had an Fe content of 85.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, and a C content of 5.0 at%; and alloy 3 had an Fe content of 89.0 at%, a Si content of 2.0 at%, a B content of 8.0 at%, and a C content of 1.0 at%;

[0061] The first step is to remove the oxide scale of the alloy raw materials and clean them. The raw materials are weighed according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace or a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, the alloy was smelted under inert gas protection and smelted repeatedly for 6 times to obtain the alloy ingot.

[0062] The second step is to vacuum up to 4×10 -3 After Pa, the mixture is filled with 99.9 vol% nitrogen for protection, and the alloy ingot is sent to the bottom of the suspension coil. The mother alloy is stably suspended at the center of the heating coil by the Lorentz force formed by the interaction between the electromagnetic field and the induced current.

[0063] The third step is to use the heating coil to induction heat the alloy until it melts, then raise the temperature to 1500℃ and keep it at that temperature for 5 minutes. After that, the heating power is turned off and the alloy is allowed to cool naturally.

[0064] In the fourth step, the “heating-holding-solidification” cycle was performed 3 and 5 times respectively, so that the alloys achieved undercooling of about 150°C and 225°C;

[0065] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0066] Step 6: stress relief annealing the obtained strip at 300°C to obtain an Fe-based amorphous alloy;

[0067] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0068] Table 3 Saturation magnetization and coercivity of FeSiBC amorphous alloys with different undercooling degrees

[0069]

[0070]

[0071] Example 4

[0072] Preparation of FeSiBCu Nanocrystalline Alloy by Supercooling Solidification

[0073] FeSiBCu system alloys were prepared, wherein the Fe content in alloy 1 was 80.5at%, the Si content was 7.0at%, the B content was 12.0at%, and the Cu content was 0.5at%; the Fe content in alloy 2 was 85.0at%, the Si content was 2.5at%, the B content was 12.0at%, and the Cu content was 0.5at%; the Fe content in alloy 3 was 85.0at%, the Si content was 1.2at%, the B content was 12.0at%, and the Cu content was 1.8at%;

[0074] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace and vacuumed to 9×10 -4 After Pa, fill with 99.9vol% purity argon gas for protection and carry out smelting, and repeat the smelting for 4 times to obtain the alloy ingot;

[0075] The second step is to place the alloy ingot into a crucible and cover its upper and lower surfaces with a mixture of purified glass of Na2B4O7 and B2O3, with a mass ratio of 1:20, so that the glass purifier completely covers the alloy ingot;

[0076] The third step is to vacuum up to 5×10 -3 After the temperature reaches 1500 Pa, the alloy is heated to molten state by argon gas with a purity of 99.9 vol%. The temperature is then raised to 1320 °C and kept at this temperature for 5 minutes. The heating power is then turned off and the alloy is allowed to cool naturally.

[0077] The fourth step is to carry out the "heating-holding-solidification" cycle treatment 3 and 4 times respectively, so that the alloy obtains a supercooling degree of about 205℃ and 255℃;

[0078] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0079] Step 6: crystallization annealing the obtained strip at 450°C to obtain Fe-based nanocrystalline alloy;

[0080] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0081] Table 4 Saturation magnetization and coercivity of FeSiBCu nanocrystalline alloys with different undercooling degrees

[0082]

[0083]

[0084] Example 5

[0085] Preparation of FeSiBNbCu Nanocrystalline Alloy by Supercooling Solidification

[0086] FeSiBNbCu system alloys were prepared, wherein alloy 1 had an Fe content of 80.0 at%, a Si content of 7.0 at%, a B content of 9.0 at%, a Nb content of 3.0 at%, and a Cu content of 1.0 at%; alloy 2 had an Fe content of 82.0 at%, a Si content of 6.0 at%, a B content of 9.0 at%, a Nb content of 2.0 at%, and a Cu content of 1.0 at%; and alloy 3 had an Fe content of 85.0 at%, a Si content of 4.5 at%, a B content of 9.0 at%, a Nb content of 0.5 at%, and a Cu content of 1.0 at%;

[0087] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, fill with 99.9vol% purity argon gas for protection and carry out smelting, and repeat the smelting for 6 times to obtain the alloy ingot;

[0088] The second step is to place the alloy ingot into a crucible and cover its upper and lower surfaces with a mixture of purified glass of Na2B4O7 and B2O3, with a mass ratio of 1:10, so that the glass purifier completely covers the alloy ingot;

[0089] The third step is to vacuum up to 8×10 -3 After Pa, fill with 99.9 vol% nitrogen gas and heat the alloy until it melts, then raise the temperature to 1380°C, keep warm for 1 minute, turn off the heating power, and let the alloy cool naturally;

[0090] In the fourth step, the “heating-holding-solidification” cycle was performed 5 and 6 times respectively, so that the alloys achieved undercooling of about 190°C and 225°C;

[0091] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0092] Step 6: crystallization annealing the obtained strip at 550°C to obtain Fe-based nanocrystalline alloy;

[0093] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0094] Table 5 Saturation magnetization and coercivity of FeSiBNbCu nanocrystalline alloys with different undercooling degrees

[0095]

[0096] Example 6

[0097] Preparation of FeSiBMoCu Nanocrystalline Alloy by Supercooling Solidification

[0098] FeSiBMoCu system alloys were prepared, wherein alloy 1 had an Fe content of 80.0 at%, a Si content of 7.0 at%, a B content of 9.0 at%, a Mo content of 3.0 at%, and a Cu content of 1.0 at%; alloy 2 had an Fe content of 82.0 at%, a Si content of 6.0 at%, a B content of 9.0 at%, a Mo content of 2.0 at%, and a Cu content of 1.0 at%; and alloy 3 had an Fe content of 83.3 at%, a Si content of 5.0 at%, a B content of 9.0 at%, a Mo content of 0.7 at%, and a Cu content of 1.0 at%;

[0099] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace and vacuumed to 8×10 -4 After Pa, fill with 99.9vol% purity argon gas for protection and carry out smelting, and repeat the smelting for 4 times to obtain the alloy ingot;

[0100] The second step is to place the alloy ingot into a crucible and cover its upper and lower surfaces with a mixture of purified glass of Na2B4O7 and B2O3 in a mass ratio of 1:1, so that the glass purifier completely covers the alloy ingot;

[0101] The third step is to vacuum to 1×10 -2 After Pa, fill with 99.9vol% pure argon gas and heat the alloy until it melts, then raise the temperature to 1370℃, keep it at that temperature for 6 minutes, turn off the heating power, and let the alloy cool naturally;

[0102] In the fourth step, the “heating-holding-solidification” cycle was performed 3 and 5 times respectively, so that the alloys achieved undercooling of about 175°C and 255°C;

[0103] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0104] Step 6: crystallization annealing the obtained strip at 500°C to obtain Fe-based nanocrystalline alloy;

[0105] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0106] Table 6 Saturation magnetization and coercivity of FeSiBMoCu nanocrystalline alloys with different undercooling degrees

[0107]

[0108]

[0109] Example 7

[0110] Preparation of FeCoSiBCCu Nanocrystalline Alloy by Supercooling Solidification

[0111] FeCoSiBCCu system alloys were prepared, wherein alloy 1 had an Fe content of 80.0 at%, a Co content of 5.0 at%, a Si content of 1.5 at%, a B content of 9.0 at%, a C content of 3.0 at%, and a Cu content of 1.5 at%; alloy 2 had an Fe content of 75.0 at%, a Co content of 10.0 at%, a Si content of 1.5 at%, a B content of 9.0 at%, a C content of 3.0 at%, and a Cu content of 1.5 at%; alloy 3 had an Fe content of 70.0 at%, a Co content of 15.0 at%, a Si content of 1.5 at%, a B content of 9.0 at%, a C content of 3.0 at%, and a Cu content of 1.5 at%;

[0112] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, fill with 99.9vol% purity argon gas for protection and carry out smelting, and repeat the smelting for 5 times to obtain the alloy ingot;

[0113] The second step is to place the alloy ingot into a crucible and cover the upper and lower surfaces of the crucible with a mixture of purified glass containing Na2B4O7 and B2O3 in a mass ratio of 1:3, so that the glass purifier completely covers the alloy ingot.

[0114] The third step is to vacuum up to 8×10 -3 After the temperature reaches 5000 Pa, the alloy is heated to molten state after being filled with 99.9 vol% nitrogen gas. The temperature is then raised to 1350°C and kept at this temperature for 8 minutes. The heating power is then turned off and the alloy is allowed to cool naturally.

[0115] In the fourth step, the “heating-holding-solidification” cycle was performed 3 and 6 times respectively, so that the alloys achieved undercooling of about 150°C and 265°C;

[0116] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0117] Step 6: crystallization annealing the obtained strip at 400°C to obtain Fe-based nanocrystalline alloy;

[0118] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0119] Table 7 Saturation magnetization and coercivity of FeCoSiBCCu nanocrystalline alloys with different undercooling degrees

[0120]

[0121]

[0122] Example 8

[0123] Preparation of FeSiBZrHfCu Nanocrystalline Alloy by Supercooling Solidification

[0124] FeSiBZrHfCu system alloys were prepared, wherein alloy 1 had an Fe content of 80.0 at%, a Si content of 6 at%, a B content of 9.0 at%, a Zr content of 3.0 at%, a Hf content of 1.0 at%, and a Cu content of 1.0 at%; alloy 2 had an Fe content of 80.0 at%, a Si content of 6.0 at%, a B content of 9.0 at%, a Zr content of 1.0 at%, a Hf content of 3.0 at%, and a Cu content of 1.0 at%; and alloy 3 had an Fe content of 87.0 at%, a Si content of 2.0 at%, a B content of 9.0 at%, a Zr content of 0.5 at%, a Hf content of 0.5 at%, and a Cu content of 1.0 at%;

[0125] The first step is to remove the oxide scale of the alloy raw materials and clean them. The raw materials are weighed according to a certain mass ratio. The weighed raw materials are placed in a vacuum induction melting furnace or a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, the alloy was smelted under inert gas protection and smelted repeatedly for 6 times to obtain the alloy ingot.

[0126] The second step is to vacuum up to 4×10 -3 After Pa, the mixture is filled with 99.9 vol% nitrogen for protection, and the alloy ingot is sent to the bottom of the suspension coil. The mother alloy is stably suspended at the center of the heating coil by the Lorentz force formed by the interaction between the electromagnetic field and the induced current.

[0127] The third step is to use the heating coil to induction heat the alloy until it melts, then raise the temperature to 1400°C and keep it at that temperature for 10 minutes. After that, the heating power is turned off and the alloy is allowed to cool naturally.

[0128] In the fourth step, the “heating-holding-solidification” cycle was performed 4 and 6 times respectively, so that the alloys achieved undercooling of about 210°C and 270°C;

[0129] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0130] Step 6: crystallization annealing the obtained strip at 550°C to obtain Fe-based nanocrystalline alloy;

[0131] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0132] Table 8 Saturation magnetization and coercivity of FeSiBZrHfCu nanocrystalline alloys with different undercooling degrees

[0133]

[0134]

[0135] Example 9

[0136] Preparation of FeSiBYCu Nanocrystalline Alloy by Supercooling Solidification

[0137] FeSiBYCu system alloys were prepared, wherein alloy 1 had an Fe content of 81.0 at%, a Si content of 4.0 at%, a B content of 9.0 at%, a Y content of 5.0 at%, and a Cu content of 1.0 at%; alloy 2 had an Fe content of 84.0 at%, a Si content of 4.0 at%, a B content of 9.0 at%, a Y content of 2.0 at%, and a Cu content of 1.0 at%; and alloy 3 had an Fe content of 87.0 at%, a Si content of 2.0 at%, a B content of 9.0 at%, a Y content of 1.0 at%, and a Cu content of 1.0 at%;

[0138] The first step is to remove the oxide scale of the alloy raw materials and clean them, and weigh the raw materials according to a certain mass ratio. The weighed raw materials are placed in a vacuum arc melting furnace and vacuumed to 8×10 -4 After Pa, the alloy was smelted under inert gas protection and smelted four times to obtain alloy ingots.

[0139] The second step is to vacuum up to 5×10 -3 After the temperature reaches 99.9 vol%, the alloy ingot is placed under the suspension coil and the mother alloy is stably suspended at the center of the heating coil by the Lorentz force generated by the interaction between the electromagnetic field and the induced current.

[0140] The third step is to use the heating coil to induction heat the alloy until it melts, then raise the temperature to 1500℃ and keep it at that temperature for 3 minutes. After that, the heating power is turned off and the alloy is allowed to cool naturally.

[0141] In the fourth step, the “heating-holding-solidification” cycle was performed 3 and 6 times respectively, so that the alloys achieved undercooling of about 180°C and 255°C;

[0142] The fifth step is to solidify the supercooled solidified alloy into a strip by rapid quenching of the melt;

[0143] Step 6: crystallization annealing the obtained strip at 500°C to obtain Fe-based nanocrystalline alloy;

[0144] The saturation magnetization and coercive force of the alloys at different undercooling degrees are shown in the following table:

[0145] Table 9 Saturation magnetization and coercivity of FeSiBYCu nanocrystalline alloys with different undercooling degrees

[0146]

[0147] In summary, the technical effect of the present invention is to improve the amorphous forming ability of Fe-based alloys by combining glass purification with cyclic overheating or electromagnetic levitation melting, achieve the goal of reducing the content of amorphous forming elements and increasing the content of ferromagnetic elements, and obtain amorphous nanocrystalline soft magnetic alloys with both saturation magnetization and low coercivity. The principle of achieving this technical effect is: during the process of glass purification combined with cyclic overheating, not only can the molten glass absorb the heterogeneous nucleation sites in the molten alloy, but the overheating and heating-heating-holding-cooling hot and cold cycles can also cause the heterogeneous nucleation sites to thermally decompose at high temperatures, and generate material exchange during the process of internal and surface heat convection, effectively reducing the heterogeneous nucleation sites inside the alloy. During the electromagnetic levitation melting process, through containerless melting, the alloy is effectively prevented from introducing impurities during the melting process, and through high-temperature overheating, the heterogeneous nucleation sites inside the alloy are thermally decomposed. Both methods can reduce or avoid crystallization and improve amorphous forming ability. On the one hand, reducing heterogeneous nucleation sites can optimize the alloy microstructure, reduce the destructive effect on magnetic exchange coupling, and increase the alloy's saturation magnetization. On the other hand, the improvement of the alloy's amorphous forming ability is conducive to the formation of a more disordered amorphous structure, effectively eliminating magnetocrystalline anisotropy, and reducing or avoiding the hindering effect of heterogeneous nucleation points on magnetic reversal, thereby obtaining low coercive force.

Claims

1. A supercooling solidification method for preparing amorphous nanocrystalline soft magnetic alloy with high Fe content, characterized by: By using molten glass purification combined with cyclic overheating, the alloy is supercooled and solidified, the amount of amorphous-forming elements added to the Fe-based amorphous nanocrystalline soft magnetic alloy is reduced, and the proportion of Fe elements is increased, thereby achieving the goal of increasing the saturation magnetization intensity and reducing the coercive force; The chemical expression of the high Fe content amorphous nanocrystalline soft magnetic alloy is FeSiBM, where M is one or more elements selected from P, C, Nb, Mo, Zr, Hf, Mo, Y, Cu, and Co, the total atomic percentage of each alloying element is 100%, and the following element contents are satisfied: Fe is 80.0 to 89.0 at%, Si is 1.0 to 9.0 at%, B is 3.0 to 12.0 at%, P is 0 to 5.0 at%, C is 0 to 5.0 at%, Nb is 0 to 3.0 at%, Zr is 0 to 3.0 at%, Hf is 0 to 3.0 at%, Mo is 0 to 3.0 at%, Y is 0 to 5.0 at%, Cu is 0 to 2.0 at%, and Co is 0 to 16.0 at%. The preparation process of the glass purifier used in the molten glass purification process includes: weighing powdered Na2B4O7 and B2O3 with a purity of not less than 98%, placing them in a high-purity corundum crucible respectively, firing them at 400-600°C for 1-8 hours, then melting and firing them at 800-1000°C for 2-16 hours, and mixing the fired Na2B4O7 and B2O3 to obtain a purifier, with the mass ratio of the two being 1:1-20.

2. A supercooling solidification method for preparing amorphous nanocrystalline soft magnetic alloy with high Fe content according to claim 1, characterized in that: The method for purifying molten glass and combining cyclic superheating comprises the following steps: The first step is to remove the oxide scale of the alloy raw materials and clean them, weigh the raw materials, and place the weighed raw materials in a vacuum induction melting furnace or a vacuum arc melting furnace, and evacuate them to at least 10 -3 After Pa, fill with inert gas protection for smelting, and repeat smelting 4 to 6 times to obtain alloy ingots; The second step is to place the alloy ingot into the crucible and cover the upper and lower surfaces of the crucible with a glass purifier so that the glass purifier completely covers the alloy ingot. The mass ratio of the glass purifier to the alloy ingot is 1:1 to 5. The third step is to vacuum to at least 10 -2 After Pa, fill with inert gas protection and heat the alloy until it melts, then raise the temperature to 1200-1500℃, keep warm for 1-10 minutes, turn off the heating power, and let the alloy cool naturally; The fourth step is to perform a "heating-holding-solidification" cycle 3 to 6 times to achieve the required undercooling of the alloy; The fifth step is to rapidly solidify the supercooled solidified alloy into a strip or powder by melt rapid quenching or atomization; In the sixth step, the obtained strip or powder is subjected to stress relief annealing to obtain an Fe-based amorphous alloy, or is subjected to crystallization annealing to obtain an Fe-based nanocrystalline alloy.

3. The method for preparing a high-Fe content amorphous nanocrystalline soft magnetic alloy by supercooling solidification according to claim 2, characterized in that: The inert gas is argon or nitrogen with a purity of not less than 99.9 vol%.

4. The method for preparing a high-Fe content amorphous nanocrystalline soft magnetic alloy by supercooling solidification according to claim 2, characterized in that: The heat-resistant temperature of the crucible is not less than 1400℃.

5. The method for preparing a high-Fe content amorphous nanocrystalline soft magnetic alloy by supercooling solidification according to claim 2, characterized in that: The annealing temperature of amorphous alloy is within the temperature range of 50 to 100° C. below the crystallization temperature, and the annealing temperature of nanocrystalline is within the temperature range of 0 to 100° C. above the crystallization temperature.

6. The method for preparing a high-Fe content amorphous nanocrystalline soft magnetic alloy by supercooling solidification according to claim 5, characterized in that: Annealing is performed in an inert gas atmosphere.

Images