High-aspect-ratio amorphous alloy and method of making same

Abstract

This invention belongs to the field of magnetic functional materials technology, specifically relating to a high rectangle ratio amorphous alloy and its preparation method. The high rectangle ratio amorphous alloy is composed of the following components by mass percentage: Cu 1.3-1.35 wt%, Nb 4.8-5.6 wt%, Si 6.4-7.2 wt%, B 1.92-2 wt%, Nd 0.5-0.8 wt%, modified chromium carbide 0.2-0.6 wt%, with the balance being Fe. This invention, through precise control of the alloy composition and the introduction of modified chromium carbide, synergistically enhances the alloy's amorphous forming ability, soft magnetic properties, and mechanical properties. The prepared high rectangle ratio amorphous alloy possesses high hardness, high saturation magnetic induction, low coercivity, and a high rectangle ratio.

Description

Technical Field

[0001] This invention belongs to the field of magnetic functional materials technology, specifically relating to a high rectangle ratio amorphous alloy and its preparation method. Background Technology

[0002] With the gradual implementation of the green development concept, the new energy industry has ushered in rapid development. The state continues to strengthen the safety protection standards for new energy power terminals, among which leakage current protection requirements for core equipment such as new energy vehicle charging piles and charging guns have been officially included in the scope of mandatory enforcement. In leakage current protectors, the magnetic core is the core component that determines its leakage current detection accuracy and response speed, and its performance indicators play a key role in the safety protection capability of the protector. According to technical standards, such magnetic cores must have excellent magnetic properties, especially meeting the stringent condition of high remanent magnetic induction intensity. Specifically, the ratio of remanent magnetic induction intensity to saturation magnetic induction intensity (i.e., the rectangularity ratio) must reach 0.92 or higher, and under ideal operating conditions, it should be increased to 0.95 or higher, thereby ensuring that the leakage current protector accurately captures and quickly cuts off mixed AC and DC leakage current signals.

[0003] From the perspective of existing technologies, cobalt-based amorphous materials have long been the primary choice for magnetic core materials meeting this performance requirement. However, cobalt, as a scarce strategic metal, remains expensive and has relatively low magnetic induction intensity, hindering the large-scale promotion and application of high-performance leakage current protectors in the new energy field. Iron-based amorphous nanocrystalline materials, using iron as the main raw material, possess the natural advantages of low cost and high magnetic induction intensity. Against this backdrop, if a novel iron-based amorphous nanocrystalline material can be developed through composition design and process optimization, achieving application standards such as a rectangularity ratio exceeding 0.92, to replace cobalt-based amorphous materials, it will effectively break through technological and cost barriers, providing crucial support for the high-quality development of the new energy leakage current protection industry. Summary of the Invention

[0004] The primary objective of this invention is to provide an amorphous alloy with a high rectangularity ratio, which combines high hardness, high saturation magnetic induction, low coercivity, and high rectangularity ratio.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned high rectangularity ratio amorphous alloy.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high rectangle ratio amorphous alloy, wherein the high rectangle ratio amorphous alloy is composed of the following components in mass percentage: Cu 1.3-1.35 wt%, Nb 4.8-5.6 wt%, Si 6.4-7.2 wt%, B 1.92-2 wt%, Nd 0.5-0.8 wt%, modified chromium carbide 0.2-0.6 wt%, and the balance being Fe.

[0008] This invention optimizes the nucleation and growth kinetics of α-Fe soft magnetic phase by controlling the Si content and synergistically adding rare earth elements Nd, Cu and Nb, thereby suppressing the formation of harmful phases. At the same time, it utilizes the Nd-induced hard magnetic phase to generate exchange coupling with the soft magnetic phase under a magnetic field, thereby effectively improving the rectangularity ratio and amorphous formation capability of the alloy.

[0009] Furthermore, the modified chromium carbide is prepared by the following process:

[0010] Chromium carbide, urea, and boric acid were added to ethanol and dispersed evenly. The ethanol was removed and the mixture was dried. After gradient calcination, modified chromium carbide was obtained.

[0011] The modified chromium carbide particles added in this invention can serve as effective heterogeneous nucleation sites in an amorphous matrix, thereby refining α-Fe grains. The boron nitride coating on the surface of the modified chromium carbide can suppress adverse reactions between chromium carbide and the melt, improve dispersibility, and enhance interfacial bonding, thereby synergistically improving the mechanical strength and soft magnetic properties of the alloy.

[0012] Furthermore, the molar ratio of chromium carbide, urea, and boric acid is 1:(0.1-0.15):(0.2-0.3).

[0013] Furthermore, the gradient calcination step is as follows: first calcining at 500-700 ℃ for 10-15 h, and then raising the temperature to 800-1000 ℃ for 2-5 h.

[0014] The above-mentioned method for preparing high-rectangular-ratio amorphous alloys includes the following steps:

[0015] (1) Mix all raw materials evenly, heat and stir under argon atmosphere, and cast and cool to obtain master alloy ingot;

[0016] (2) The master alloy ingot is crushed, cleaned and melted, and then amorphous ribbon is obtained by single-roller spinning;

[0017] (3) The amorphous ribbon is heat-treated under a longitudinal magnetic field and cooled to obtain the high moment ratio amorphous alloy.

[0018] Further, the heating and stirring process in step (1) is as follows: first heat to 800-1000 ℃ and keep warm for 2-5 min, then heat to 1500-1550 ℃ and stir for 10-20 min.

[0019] Furthermore, the roller speed of the single-roller belt spinning in step (2) is 40-50 m / s.

[0020] Furthermore, the magnetic field strength of the longitudinal magnetic field in step (3) is 1-3 kA / m; the temperature of the heat treatment is 370-550 ℃, and the time is 7-10 h.

[0021] The above technical solution utilizes a longitudinal magnetic field and heat treatment steps to induce magnetic domains to align in an oriented manner along the easy magnetization direction, thereby achieving a magnetic structure with a high rectangularity ratio.

[0022] The beneficial technical effects of this invention are as follows:

[0023] 1. This invention improves the amorphous forming ability, soft magnetic properties and mechanical properties of the alloy by precisely controlling the alloy composition and introducing modified chromium carbide.

[0024] 2. This invention utilizes the atomic size differences between Si, B, and Fe, as well as the large atomic size of rare-earth Nd, to jointly increase the internal disorder of the alloy, thereby enhancing its amorphous formation capability. Simultaneously, by adjusting the Si content and synergistically utilizing Cu to promote nucleation and Nb to inhibit grain growth, the precipitation of the α-Fe soft magnetic phase and grain size are effectively controlled. Crucially, the addition of trace amounts of Nd promotes Nd₂Fe… 14 The formation of the B hard magnetic phase enables it to undergo exchange coupling with the α-Fe soft magnetic phase in the longitudinal magnetic field, thereby significantly improving the rectangularity ratio of the alloy.

[0025] 3. This invention further improves the mechanical and soft magnetic properties of the alloy by introducing hexagonal boron nitride-coated modified chromium carbide particles. These particles can act as nanocrystal nucleation sites in the amorphous matrix, promoting the uniform nucleation of α-Fe nanocrystals and pinning grain boundaries, inhibiting grain boundary migration and nanocrystal growth, thus refining the grains and effectively improving the mechanical properties and saturation magnetic induction of the alloy. The surface-coated hexagonal boron nitride reduces the interfacial energy between chromium carbide and the alloy matrix, improving the wettability between the matrix and the particles, thereby optimizing the particle dispersion uniformity and interfacial bonding, further enhancing mechanical and soft magnetic properties. Furthermore, boron nitride exhibits high stability, inhibiting the reaction of Fe, Si, and other elements with chromium carbide in the alloy melt, preventing the formation of brittle phases, and improving alloy performance. Attached Figure Description

[0026] Figure 1 This is a scanning electron microscope image of the modified chromium carbide prepared in Example 1 of the present invention. Detailed Implementation

[0027] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0028] (I) Implementation Examples

[0029] Example 1

[0030] Example 1 provides a high rectangularity ratio amorphous alloy, which is composed of the following components by mass percentage: Cu 1.3 wt%, Nb 5.1 wt%, Si 6.8 wt%, B 1.95 wt%, Nd 0.7 wt%, modified chromium carbide 0.4 wt%, with the balance being Fe;

[0031] The modified chromium carbide is prepared by the following process:

[0032] Following the ratio of chromium carbide, urea, boric acid, and ethanol (1 mol: 0.13 mol: 0.2 mol: 2.3 L), chromium carbide, urea, and boric acid were added to ethanol and ultrasonically dispersed until homogeneous. After removing most of the ethanol by rotary evaporation and drying, the mixture was calcined at 600 °C for 12 h, followed by calcination at 900 °C for 3 h to obtain modified chromium carbide. The scanning electron microscope image of this modified chromium carbide is shown below. Figure 1 As shown.

[0033] This embodiment also provides a method for preparing the above-mentioned high rectangularity ratio amorphous alloy, the specific steps of which are as follows:

[0034] (1) After mixing the raw materials evenly according to the above mass percentages, transfer them into the melting furnace and evacuate the melting chamber to 10°C. -4 The pressure is below Pa to remove impurities such as oxygen and moisture. Then, high-purity argon is introduced to a slightly positive pressure state for melting: first, heat at 900℃ for 3 min, then raise the temperature to 1500℃ and stir electromagnetically for 15 min, and finally pour into a water-cooled mold. After cooling, the master alloy ingot is obtained.

[0035] (2) The above-mentioned master alloy ingot is crushed, cleaned, dried and then placed in a quartz tube for induction melting. Then, it is thrown out at a roller speed of 40 m / s using a single roller throwing method to obtain amorphous ribbon.

[0036] (3) The above amorphous ribbon was placed in a longitudinal magnetic field of 2 kA / m and heat-treated at 420 °C for 8 h. After cooling, a high rectangularity ratio amorphous alloy was obtained.

[0037] Example 2

[0038] Example 2 provides a high rectangularity ratio amorphous alloy, which is composed of the following components by mass percentage: Cu 1.3 wt%, Nb 4.8 wt%, Si 6.4 wt%, B 1.92 wt%, Nd 0.5 wt%, modified chromium carbide 0.2 wt%, with the balance being Fe;

[0039] The modified chromium carbide is prepared by the following process:

[0040] According to the ratio of chromium carbide, urea, boric acid and ethanol 1 mol: 0.1 mol: 0.2 mol: 2 L, chromium carbide, urea and boric acid were added to ethanol and ultrasonically dispersed evenly. After removing most of the ethanol by rotary evaporation, the mixture was dried and then calcined at 500 ℃ for 10 h, and then calcined at 800 ℃ for 2 h to obtain modified chromium carbide.

[0041] This embodiment also provides a method for preparing the above-mentioned high rectangularity ratio amorphous alloy, the specific steps of which are as follows:

[0042] (1) After mixing the raw materials evenly according to the above mass percentages, transfer them into the melting furnace and evacuate the melting chamber to 10°C. -4 The pressure is below Pa to remove impurities such as oxygen and moisture. Then, high-purity argon is introduced to a slightly positive pressure state for melting: first, heat at 800℃ for 2 min, then raise the temperature to 1500℃ and stir electromagnetically for 10 min, and finally pour into a water-cooled mold. After cooling, the master alloy ingot is obtained.

[0043] (2) The above-mentioned master alloy ingot is crushed, cleaned, dried and then placed in a quartz tube for induction melting. Then, it is thrown out at a roller speed of 40 m / s using a single roller throwing method to obtain amorphous ribbon.

[0044] (3) The above amorphous ribbon was placed in a longitudinal magnetic field of 1 kA / m and heat-treated at 370 °C for 7 h. After cooling, a high rectangularity ratio amorphous alloy was obtained.

[0045] Example 3

[0046] Example 3 provides a high rectangularity ratio amorphous alloy, which is composed of the following components by mass percentage: Cu 1.35 wt%, Nb 5.6 wt%, Si 7.2 wt%, B 2 wt%, Nd 0.8 wt%, modified chromium carbide 0.6 wt%, with the balance being Fe;

[0047] The modified chromium carbide is prepared by the following process:

[0048] According to the ratio of chromium carbide, urea, boric acid and ethanol, 1 mol: 0.15 mol: 0.3 mol: 2.5 L, chromium carbide, urea and boric acid were added to ethanol and ultrasonically dispersed evenly. After removing most of the ethanol by rotary evaporation, the mixture was dried and then calcined at 700 ℃ for 15 h, and then calcined at 1000 ℃ for 5 h to obtain modified chromium carbide.

[0049] This embodiment also provides a method for preparing the above-mentioned high rectangularity ratio amorphous alloy, the specific steps of which are as follows:

[0050] (1) After mixing the raw materials evenly according to the above mass percentages, transfer them into the melting furnace and evacuate the melting chamber to 10°C. -4 The pressure is below Pa to remove impurities such as oxygen and moisture. Then, high-purity argon is introduced to a slightly positive pressure state for melting: first, heat at 1000℃ for 5 min, then raise the temperature to 1550℃ and stir electromagnetically for 20 min, and finally pour into a water-cooled mold. After cooling, the master alloy ingot is obtained.

[0051] (2) The above-mentioned master alloy ingot is crushed, cleaned, dried and then placed in a quartz tube for induction melting. Then, it is thrown out at a roller speed of 50 m / s using a single roller throwing method to obtain amorphous ribbon.

[0052] (3) The above amorphous ribbon was placed in a longitudinal magnetic field of 3 kA / m and heat-treated at 550 °C for 10 h. After cooling, a high rectangularity ratio amorphous alloy was obtained.

[0053] (ii) Comparative Example

[0054] Comparative Example 1

[0055] Comparative Example 1 is basically the same as Example 1, except that Nd is omitted in Example 1 and the Si content is adjusted to 8.5 wt%.

[0056] Comparative Example 2

[0057] Comparative Example 2 is basically the same as Example 1, except that the modified chromium carbide in Example 1 is omitted.

[0058] Comparative Example 3

[0059] Comparative Example 3 is basically the same as Example 1, except that the modified chromium carbide in Example 1 is replaced with chromium carbide.

[0060] (III) Test Examples

[0061] The performance of the amorphous alloys prepared in Examples 1-3 and Comparative Examples 1-3 was tested.

[0062] Hardness test: The hardness of each amorphous alloy was tested according to GB / T 4340.1-2024 "Metallic materials Vickers hardness test - Part 1: Test method", and the results are shown in Table 1.

[0063] The saturation magnetic induction intensity, coercivity and rectangularity ratio of each amorphous alloy were tested using a soft magnetic DC (AC) tester. The test results are shown in Table 1.

[0064] Table 1. Test results of hardness, saturation magnetic induction, coercivity, and rectangularity ratio of various amorphous alloys.

[0065]

[0066] As shown in Table 1, the high rectangularity amorphous alloys prepared in Examples 1-3 of the present invention all exhibit excellent comprehensive properties: high hardness, high saturation magnetic induction intensity, low coercivity and high rectangularity ratio.

[0067] Compared to Example 1, Comparative Example 1 omitted Nd and adjusted Si to 8.5 wt%, resulting in a significant deterioration in all its properties, especially a marked decrease in the rectangularity ratio and a reduction in saturation magnetic induction intensity of approximately 14.8%. This indicates that the addition of Nd and precise control of Si content are crucial for achieving a high rectangularity ratio in this invention. Specifically, excessive Si easily forms a non-magnetic Fe3Si phase, impairing soft magnetic properties; while the absence of trace amounts of Nd prevents the formation of sufficient Nd2Fe. 14 The effective exchange coupling between the B hard magnetic phase and the α-Fe soft magnetic phase under longitudinal magnetic field heat treatment is the fundamental reason for the loss of rectangularity.

[0068] Compared to Example 1, Comparative Example 2, which omitted modified chromium carbide, showed a significant decrease in hardness and saturation magnetic flux density, while its coercivity increased. This indicates that the lack of chromium carbide particles resulted in the absence of crucial heterogeneous nucleation and grain boundary pinning effects, leading to grain coarsening and a comprehensive decline in mechanical and soft magnetic properties. Comparative Example 3, which replaced the modified chromium carbide with chromium carbide, exhibited better performance than Comparative Example 2, but its coercivity was still significantly higher than that of Example 1, and its saturation magnetic flux density was also lower. This suggests that the unmodified chromium carbide had poor interfacial bonding with the matrix, potentially triggering agglomeration or harmful interfacial reactions, increasing the resistance to domain wall migration (manifested as high coercivity), while interfacial defects also reduced the effective magnetic flux density. Therefore, simply adding chromium carbide or not adding it at all cannot achieve optimal performance. This invention effectively solves the interfacial compatibility problem between chromium carbide and the matrix through hexagonal boron nitride coating modification. The coating improves dispersibility, enhances interfacial bonding, and inhibits harmful reactions, thereby enabling chromium carbide to fully exert its synergistic enhancement effects of refining grains, increasing hardness and saturation magnetic induction, and significantly reducing coercivity. This is the key to obtaining low coercivity, high rectangularity ratio, and high hardness in the embodiments.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A high aspect ratio amorphous alloy, characterized by, The high rectangularity ratio amorphous alloy consists of the following components by mass percentage. Composition: Cu 1.3-1.35 wt%, Nb 4.8-5.6 wt%, Si 6.4-7.2 wt%, B 1.92-2 wt%, Nd 0.5-0.8 wt%, modified chromium carbide 0.2-0.6 wt%, balance Fe; The modified chromium carbide is prepared by the following process: Chromium carbide, urea, and boric acid were added to ethanol and dispersed evenly. The ethanol was removed and the mixture was dried. Modified chromium carbide was obtained by gradient calcination. The molar ratio of chromium carbide, urea, and boric acid is 1:(0.1-0.15):(0.2-0.3); the gradient calcination step is as follows: first calcining at 500-700 ℃ for 10-15 h, and then raising the temperature to 800-1000 ℃ for 2-5 h.

2. A method of producing the high aspect ratio amorphous alloy of claim 1, characterized by, Includes the following steps: (1) Mix all raw materials evenly, heat and stir under argon atmosphere, and then cast and cool to obtain master alloy ingot; (2) The master alloy ingot is crushed, cleaned and melted, and then amorphous ribbon is obtained by single-roller spinning; (3) Under a longitudinal magnetic field, the amorphous ribbon is heat-treated and cooled to obtain the high rectangularity ratio amorphous alloy.

3. The method of claim 2, wherein the high aspect ratio amorphous alloy is prepared by a method comprising: The heating and stirring process described in step (1) is as follows: first heat to 800-1000 ℃ and keep warm for 2-5 min, then raise the temperature to 1500-1550 ℃ and stir for 10-20 min.

4. The method for preparing a high-rectangular-ratio amorphous alloy according to claim 2, characterized in that, The roller speed of the single roller belt in step (2) is 40-50 m / s.

5. The method for preparing a high rectangularity ratio amorphous alloy according to claim 2, characterized in that, The magnetic field strength of the longitudinal magnetic field in step (3) is 1-3 kA / m; the temperature of the heat treatment is 370-550 ℃ and the time is 7-10 h.

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