A high-toughness nanocrystalline soft magnetic alloy strip and its preparation method

Abstract

The present invention relates to the technical field of soft magnetic materials, and in particular to a high-toughness nanocrystalline soft magnetic alloy strip and a preparation method thereof. The present invention provides a high-toughness nanocrystalline soft magnetic alloy strip, the chemical composition of which is expressed as Fe (100‑a‑b‑c‑d‑e) Si a B b Nb c P d Cu e , where a, b, c, d, and e represent the atomic percentages of Si, B, Nb, P, and Cu, respectively, and satisfy the following conditions: 3≤a≤4, 7≤b≤9, 2≤c≤3, 0.5≤d≤1, and e=1. The soft magnetic alloy strip of the present invention has high toughness while also taking into account electromagnetic properties. The soft magnetic alloy strip is not easily broken during the winding process of the iron core, greatly improving the production efficiency and automation level of the winding iron core.

Description

Technical Field

[0001] The present invention relates to the technical field of soft magnetic materials, in particular to a method for preparing a high-toughness nanocrystalline soft magnetic alloy strip. Background Art

[0002] Soft magnetic materials are functional magnetic materials characterized by high saturation magnetization, high magnetic permeability, and low coercivity, making them widely used in the power electronics industry. There are three main types of soft magnetic materials: metallic soft magnetic materials, soft magnetic composite materials, and ferrites. Metallic soft magnetic materials have excellent overall magnetic properties and low resistivity, making them generally suitable for low-frequency applications. Ferrite, a ferrimagnetic material, has a low saturation magnetic induction intensity and is generally large in size when used. However, its high resistivity makes it suitable for high-frequency applications. Soft magnetic composite materials have higher resistivity than metallic soft magnetic materials and higher saturation magnetic induction intensity than ferrites, allowing for higher frequency applications while also meeting the demands of miniaturization.

[0003] Nanocrystalline soft magnetic alloy materials have been widely used due to their high saturation magnetic induction intensity, high magnetic permeability, low loss, and good temperature stability. For example, nanocrystalline soft magnetic alloy materials can be prepared into strips, which are then wound into iron cores of various specifications to create various inductor components for use in various electronic fields. Winding iron cores can be done manually or using automatic winding machines. However, due to their thinness, nanocrystalline soft magnetic alloy strips are easily brittle and break easily during the winding process, seriously affecting production efficiency and the degree of automation. Summary of the Invention

[0004] The present invention aims to provide a high-toughness nanocrystalline soft magnetic alloy strip and a method for preparing the same. The soft magnetic alloy strip of the present invention combines high toughness with electromagnetic performance, is less prone to breaking during the core winding process, and significantly improves the production efficiency and automation level of the core winding process.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a high-toughness nanocrystalline soft magnetic alloy strip, the chemical composition of the soft magnetic alloy strip is expressed as Fe (100-a-b-c-d-e) Si a B b Nb c P d Cu e , where a, b, c, d, and e represent the atomic percentages of Si, B, Nb, P, and Cu, respectively, and satisfy the following conditions: 3≤a≤4, 7≤b≤9, 2≤c≤3, 0.5≤d≤1, and e=1.

[0007] The present invention improves the toughness of a soft magnetic alloy strip by adjusting its chemical composition and preparation method. The Fe content added in the present invention is within the range of 82-86.5%. The high Fe content makes the saturation magnetization intensity of nanocrystals higher. The added Si and P improve the amorphous forming ability of the alloy. A small amount of Nb and Cu is added while the B content is strictly controlled so that the soft magnetic alloy strip has high toughness while taking into account electromagnetic properties. The bending radius of the soft magnetic alloy strip can be controlled to 0.5 cm. Furthermore, the soft magnetic alloy strip is not easily broken when wound by an automatic winding machine, thereby greatly improving the winding efficiency and automation level of the iron core and ensuring the consistency of the product.

[0008] Furthermore, the chemical composition expression of the soft magnetic alloy strip is Fe (100-a-b-c-d-e) Si a B b Nb c P d Cu e , where a, b, c, d, and e represent the atomic percentages of Si, B, Nb, P, and Cu, respectively, and satisfy the following conditions: 3≤a≤4, 8≤b≤9, 2.8≤c≤3, 0.5≤d≤1, and e=1.

[0009] Furthermore, the bending radius R of the soft magnetic alloy strip is less than 0.5 cm.

[0010] Furthermore, the saturation magnetization intensity of the soft magnetic alloy strip is 1.65-1.70T.

[0011] The present invention also provides a method for preparing the above-mentioned high-toughness nanocrystalline soft magnetic alloy strip, comprising the following steps:

[0012] S1. Ingredients

[0013] Fe, Si, B, Nb, P and Cu are prepared according to their atomic percentage contents;

[0014] S2. Melting

[0015] The raw materials prepared in step S1 are placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a smelting temperature of 1400-1600°C, a vacuum degree of 0.2-1 Pa, and a smelting time of 2-4 hours. The alloy melt is poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device is 0.1-0.2 MPa.

[0016] S3. Secondary smelting

[0017] The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1000-1300° C. and a smelting time of 40-60 min;

[0018] S4. Preparation of soft magnetic alloy strip.

[0019] Furthermore, step S4 is specifically as follows: pouring the molten steel into a preheated tundish through a runner, wherein the preheating temperature of the tundish is not lower than the temperature of the molten steel; the molten steel is sprayed from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a nanocrystalline soft magnetic alloy strip.

[0020] Furthermore, the nanocrystalline soft magnetic alloy strip has a thickness of 18-22 μm and a width of 2-70 mm.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The present invention improves the toughness of the soft magnetic alloy strip by adjusting the chemical composition and preparation method, so that the soft magnetic alloy strip has high toughness while taking into account the electromagnetic properties.

[0023] (2) The soft magnetic alloy strip of the present invention has high toughness, and its bending radius can be controlled to 0.5 cm. Therefore, the soft magnetic alloy strip is not easily broken when wound by an automatic winding machine, which greatly improves the winding efficiency and automation level of the iron core and ensures the consistency of the product. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0025] Example 1

[0026] A high-toughness nanocrystalline soft magnetic alloy strip, the chemical formula of the soft magnetic alloy strip is Fe 82 Si4B9Nb3P1Cu1.

[0027] The method for preparing the soft magnetic alloy strip comprises the following steps:

[0028] S1. Ingredients

[0029] The ingredients are prepared according to the atomic percentage content of 82% Fe, 4% Si, 9% B, 3% Nb, 1% P, and 1% Cu;

[0030] S2. Melting

[0031] The prepared raw materials were placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a melting temperature of 1500°C, a vacuum degree of 0.2 Pa, and a melting time of 2 hours. The alloy melt was poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device was 0.15 MPa.

[0032] S3. Secondary smelting

[0033] The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1200° C. and a smelting time of 50 min;

[0034] S4. Preparation of soft magnetic alloy strip

[0035] The molten steel is poured into a preheated tundish through a runner. The preheating temperature of the tundish is not lower than the temperature of the molten steel. The molten steel is sprayed from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a nanocrystalline soft magnetic alloy strip. The thickness of the strip is 18 μm and the width is 2 mm.

[0036] Example 2

[0037] A high-toughness nanocrystalline soft magnetic alloy strip, the chemical formula of the soft magnetic alloy strip is Fe 84.2 Si3B8Nb 2.8 P1Cu1.

[0038] The method for preparing the soft magnetic alloy strip comprises the following steps:

[0039] S1. Ingredients

[0040] The ingredients are prepared according to the atomic percentage content of 84.2% Fe, 3% Si, 8% B, 2.8% Nb, 1% P, and 1% Cu;

[0041] S2. Melting

[0042] The prepared raw materials were placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a melting temperature of 1500°C, a vacuum degree of 0.4 Pa, and a melting time of 3 hours. The alloy melt was poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device was 0.1 MPa.

[0043] S3. Secondary smelting

[0044] The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1000° C. and a smelting time of 60 min;

[0045] S4. Preparation of soft magnetic alloy strip

[0046] The molten steel is poured into a preheated tundish through a runner. The preheating temperature of the tundish is not lower than the temperature of the molten steel. The molten steel is sprayed from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a nanocrystalline soft magnetic alloy strip. The thickness of the strip is 19 μm and the width is 20 mm.

[0047] Example 3

[0048] A high-toughness nanocrystalline soft magnetic alloy strip, the chemical composition expression of the soft magnetic alloy strip is Fe 85 Si 3.2 B8Nb2P 0.8 Cu1.

[0049] The method for preparing the soft magnetic alloy strip comprises the following steps:

[0050] S1. Ingredients

[0051] The ingredients are prepared according to the atomic percentage content of 85% Fe, 3.2% Si, 8% B, 2% Nb, 0.8% P, and 1% Cu;

[0052] S2. Melting

[0053] The prepared raw materials were placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a melting temperature of 1500°C, a vacuum degree of 0.6 Pa, and a melting time of 3 hours. The alloy melt was poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device was 0.1 MPa.

[0054] S3. Secondary smelting

[0055] The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1200° C. and a smelting time of 45 minutes;

[0056] S4. Preparation of soft magnetic alloy strip

[0057] The molten steel is poured into a preheated tundish through a runner. The preheating temperature of the tundish is not lower than the temperature of the molten steel. The molten steel is sprayed from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a nanocrystalline soft magnetic alloy strip. The thickness of the strip is 20 μm and the width is 50 mm.

[0058] Example 4

[0059] A high-toughness nanocrystalline soft magnetic alloy strip, the chemical composition expression of the soft magnetic alloy strip is Fe 86.5 Si3B7Nb2P 0.5 Cu1.

[0060] The method for preparing the soft magnetic alloy strip comprises the following steps:

[0061] S1. Ingredients

[0062] The ingredients are prepared according to the atomic percentage content of 86.5% Fe, 3% Si, 7% B, 2% Nb, 0.5% P, and 1% Cu;

[0063] S2. Melting

[0064] The prepared raw materials were placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a melting temperature of 1500°C, a vacuum degree of 1 Pa, and a melting time of 4 hours. The alloy melt was poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device was 0.2 MPa.

[0065] S3. Secondary smelting

[0066] The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1300° C. and a smelting time of 40 min.

[0067] S4. Preparation of soft magnetic alloy strip

[0068] The molten steel is poured into a preheated tundish through a runner. The preheating temperature of the tundish is not lower than the temperature of the molten steel. The molten steel is sprayed from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a nanocrystalline soft magnetic alloy strip. The thickness of the strip is 22 μm and the width is 70 mm.

[0069] Comparative Example 1

[0070] The same as Example 1, except that the chemical composition of the soft magnetic alloy strip is expressed as Fe 81 Si4B9Nb3P1Cu2;

[0071] In step S1 of the method for preparing the soft magnetic alloy strip, the ingredients are prepared according to the atomic percentage content of 81% Fe, 4% Si, 9% B, 3% Nb, 1% P, and 2% Cu.

[0072] Comparative Example 2

[0073] The same as Example 1, except that the chemical composition of the soft magnetic alloy strip is expressed as Fe 87 Si1B 9.5 Nb1P 0.5 Cu1;

[0074] In step S1 of the method for preparing the soft magnetic alloy strip, the ingredients are prepared according to the atomic percentage content of 87% Fe, 1% Si, 9.5% B, 1% Nb, 0.5% P, and 1% Cu.

[0075] Comparative Example 3

[0076] The same as Example 1, except that the chemical composition of the soft magnetic alloy strip is expressed as Fe 83 Si5B6Nb4P 0.2 Cu 1.8 ;

[0077] In step S1 of the method for preparing the soft magnetic alloy strip, the ingredients are prepared according to the atomic percentage content of 83% Fe, 5% Si, 6% B, 4% Nb, 0.2% P, and 1.8% Cu.

[0078] Comparative Example 4

[0079] The same as Example 1, except that the chemical composition of the soft magnetic alloy strip is expressed as Fe 84 Si5B 5.5 Nb3P 1.5 Cu1;

[0080] In step S1 of the method for preparing the soft magnetic alloy strip, the ingredients are prepared according to the atomic percentage content of 84% Fe, 5% Si, 5.5% B, 3% Nb, 1.5% P, and 1% Cu.

[0081] Test Example 1 Electromagnetic Performance Test

[0082] The soft magnetic alloy strips prepared in Examples 1-4 and Comparative Examples 1-4 were tested for saturation magnetic induction intensity, maximum magnetic permeability, coercive force and magnetic loss. The specific results are shown in Table 1.

[0083] Table 1 Electromagnetic properties and toughness of soft magnetic alloy strips

[0084]

[0085]

[0086] It can be seen from the data in Table 1 that compared with the soft magnetic alloy strips prepared in Comparative Examples 1-4, the soft magnetic alloy strips prepared in Examples 1-4 have higher saturation magnetic induction intensity and maximum magnetic permeability, and lower coercive force and magnetic loss, indicating that the soft magnetic alloy strips prepared in Examples 1-4 have excellent electromagnetic properties.

[0087] Test Example 2 Toughness and bendability test

[0088] The specific test method for toughness is to fold the soft magnetic alloy strip in half and pass it through a 0.5mm or 1.5mm slit. If the soft magnetic alloy strip passes through the slit without breaking, it is qualified; if it breaks, it is unqualified.

[0089] Another toughness test method was used to test the toughness of the soft magnetic alloy strips prepared in Examples 1-4 and Comparative Examples 1-4: a soft magnetic alloy strip with a thickness of t was placed vertically between two parallel plates, and the spacing d between the parallel plates was shortened until the soft magnetic alloy strip was completely folded in half. The toughness of the soft magnetic alloy strip is expressed as ε = t / (dt). If 0 < ε ≤ t, the soft magnetic alloy strip is brittle fracture. If ε = 1, it means that the soft magnetic alloy strip is folded 180° without breaking and has good toughness. The curvature of the soft magnetic alloy strips prepared in Examples 1-4 and Comparative Examples 1-4 was tested. The curvature is represented by the bending radius R (cm) of the soft magnetic alloy strip after heat treatment. The specific results are shown in Table 2.

[0090] Table 2 Toughness and bendability test of soft magnetic alloy strip

[0091]

[0092]

[0093] It can be seen from the data in Table 2 that the soft magnetic alloy strips prepared in Comparative Examples 1-4 do not break after being folded in half and pass through a 0.5 mm slit, but break when passing through a 1.5 mm slit. The soft magnetic alloy strips prepared in Examples 1-4 do not break after being folded in half and pass through both 0.5 mm and 1.5 mm slits, and the toughness ε of the soft magnetic alloy strips prepared in Examples 1-4 is 1, and the bending radius R is less than 0.5 cm. Compared with Comparative Examples 1-4, the soft magnetic alloy strips prepared in Examples 1-4 have higher toughness and a smaller bending radius.

[0094] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be included therein.

[0095] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A high-toughness nanocrystalline soft magnetic alloy strip, characterized in that: The chemical composition expression of the soft magnetic alloy strip is Fe (100-a-b-c-d-e) Si a B b Nb c P d Cu e , where a, b, c, d, and e represent the atomic percentages of Si, B, Nb, P, and Cu, respectively, and satisfy the following conditions: 3≤a≤4, 8≤b≤9, 2.8≤c≤3, 0.5≤d≤1, and e=1; the bending radius R of the soft magnetic alloy strip is less than 0.5 cm; and the saturation magnetization intensity of the soft magnetic alloy strip is 1.65-1.70 T; The soft magnetic alloy strip is obtained by the following preparation method: S1. Ingredients S2. Melting The raw materials prepared in step S1 are placed in a medium frequency vacuum induction furnace for smelting to obtain an alloy melt at a smelting temperature of 1400-1600°C, a vacuum degree of 0.2-1 Pa, and a smelting time of 2-4 hours. The alloy melt is poured into a rotary casting plate equipped with a cooling device to form an alloy ingot. The circulating water pressure in the cooling device is 0.1-0.2 MPa. S3. Secondary smelting The alloy ingot is placed in a crucible on a belt spouting machine for secondary smelting to obtain molten steel at a smelting temperature of 1000-1300° C. and a smelting time of 40-60 min; S4. Preparation of soft magnetic alloy strip.

2. The method for preparing a high-toughness nanocrystalline soft magnetic alloy strip according to claim 1, characterized in that: The soft magnetic alloy strip has a thickness of 18-22 μm and a width of 2-70 mm.

3. The method for preparing a high-toughness nanocrystalline soft magnetic alloy strip according to claim 1, characterized in that: Step S4 specifically comprises pouring the molten steel in step S3 into a preheated tundish through a runner, wherein the preheating temperature of the tundish is not lower than the temperature of the molten steel, and spraying the molten steel from a nozzle at the bottom of the tundish onto a copper roller equipped with a quenching device and rotating at high speed to form a soft magnetic alloy strip.

Images