Low coercivity Wiegand wire and preparation method thereof

Abstract

The present invention provides a low-coercive force Wiegand wire and a preparation method thereof. The components of the Wiegand wire include, by weight percentage: Ni 10wt% to 15wt%, Co 3wt% to 7wt%, Al 2wt% to 5wt%, Si 1wt% to 4wt%, Mn 1wt% to 3wt%, Ti 0.5wt% to 2wt%, Al2O3 2wt% to 5wt%, Nd 0.2wt% to 0.6wt%, and the remainder is Fe and other inevitable impurities. The preparation steps include raw material weighing, smelting, quenching, heat treatment and multi-stage drawing, and the magnetic properties are further optimized by applying a magnetic field during the process. The present invention effectively reduces the coercive force of the Wiegand wire by combining nano-scale alumina particles with rare earth elements, while improving the saturation magnetic induction intensity, and is suitable for the application of high-precision sensors and low-energy magnetic components.

Description

Technical Field

[0001] The present invention relates to the technical field of Wiegand wires, in particular to a low-coercivity Wiegand wire and a preparation method thereof. Background Art

[0002] With the rapid development of modern magnetic materials science, especially in high-tech fields such as electronic devices, sensors and motors, the demand for Wiegand wires has gradually increased. Wiegand wires are widely used due to their unique magnetic properties, especially in magnetic reversal and low-energy consumption applications. However, the performance of current Wiegand wires is limited by the contradiction between the coercive force and magnetic permeability of the material. Traditional Wiegand wires are mainly composed of metal alloys. Although they can meet application requirements to a certain extent, their high coercive force often leads to increased energy loss and affects the response speed and sensitivity of the system. This limitation has prompted researchers to seek new composite materials to overcome the shortcomings of existing technologies in magnetic material performance and promote the development and application of new magnetic materials.

[0003] Current technological approaches primarily focus on improving Wiegand wire performance by optimizing metal alloy composition, controlling processing techniques, and improving annealing. However, these methods remain insufficient in reducing coercivity and increasing magnetic permeability. In particular, under dynamic magnetic field conditions, existing materials often struggle to achieve ideal magnetic properties, failing to meet the demands of high-precision sensors and fast-response systems. Summary of the Invention

[0004] Current technological approaches primarily focus on improving Wiegand wire performance by optimizing metal alloy composition, controlling processing techniques, and improving annealing. However, these methods remain insufficient in reducing coercivity and increasing magnetic permeability. In particular, under dynamic magnetic field conditions, existing materials often struggle to achieve ideal magnetic properties, failing to meet the demands of high-precision sensors and fast-response systems.

[0005] The present application provides a low coercive force Wiegand wire, which includes, in percentage by weight: Ni 10wt% to 15wt%, Co 3wt% to 7wt%, Al 2wt% to 5wt%, Si 1wt% to 4wt%, Mn 1wt% to 3wt%, Ti 0.5wt% to 2wt%, Al2O3 2wt% to 5wt%, Nd 0.2wt% to 0.6wt%, and the balance is Fe and other inevitable impurities.

[0006] As a preferred technical solution for low coercive force Wiegand wire, it includes, in weight percentage: Ni 13wt%, Co 4wt%, Al 3wt%, Si 4wt%, Mn 2wt%, Ti 0.5wt%, Al2O3 3wt%, Nd 0.4wt%, and the balance is Fe and other inevitable impurities.

[0007] In addition, the present application provides a method for preparing low coercive force Wiegand wire, comprising the following preparation steps:

[0008] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio;

[0009] S2. The weighed powders in step S1 are uniformly mixed in a planetary ball mill according to proportion, and the mixed powders are melted in a vacuum induction furnace at a temperature set at 1450°C-1600°C for 1-2 hours;

[0010] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 1 to 2 minutes;

[0011] S4. The quenched alloy billet is heated to 600°C-800°C and maintained at this temperature for 4 hours, followed by natural cooling to room temperature;

[0012] S5. The heat-treated billet is preheated in a heating furnace, and then the preheated billet is introduced into a drawing machine and stretched by applying a uniform tensile force;

[0013] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer, with the pickling temperature set at 50°C-60°C for 15 minutes using a 5wt%-10wt% sulfuric acid solution, followed by sandblasting.

[0014] As a preferred technical solution for the preparation of a low-coercivity Wiegand wire, the particle size of the Al2O3 powder ranges from 100 nm to 300 nm.

[0015] It should be noted that, first, the surface area of nano-scale particles is relatively large, which can form more interfaces in the alloy. These interfaces can inhibit the formation and movement of magnetic domains, thereby reducing the coercive force. Secondly, smaller particles promote the refinement of grains in the alloy. The refined grains can effectively hinder the movement of magnetic domains, further reducing the coercive force of the material. In addition, Al2O3, as an insulating material, acts as an isolation agent in the alloy, which can reduce magnetic coupling and alleviate hysteresis. Finally, the uniform distribution and good dispersibility of Al2O3 powder can improve the overall stability of the material and ensure the consistency and reliability of the magnetic properties. Therefore, reasonable control of the particle size of Al2O3 powder can not only improve the comprehensive performance of the alloy, but also significantly reduce its coercive force.

[0016] As a preferred technical solution for the preparation of low-coercivity Wiegand wire, when applying a magnetic field during the drawing stage, a constant magnetic field of 100 mT to 500 mT is used, and the direction of the magnetic field is consistent with the drawing direction.

[0017] It should be noted that the external magnetic field and its direction have a profound impact on the magnetic induction intensity and coercivity of the material. When an external magnetic field is applied during the processing of magnetic materials, the magnetic domains tend to rearrange along the direction of the external magnetic field. This orderly magnetic domain orientation enhances the net magnetic moment of the material, thereby improving the magnetic induction intensity. At the same time, the external magnetic field reduces the energy barrier to the movement of the magnetic domain walls, making them more mobile, reducing internal stress and defects, and thus reducing the coercivity. In particular, when the direction of the external magnetic field is consistent with the processing direction, for example, parallel to the pulling direction, it can promote the preferential orientation of grains and magnetic domains, ultimately achieving optimized magnetic properties.

[0018] As a preferred technical solution for the preparation method of low coercivity Wiegand wire, step S5 specifically includes the following steps:

[0019] In the first stage of drawing, the alloy billet is heated to 800°C to 1000°C. Within this temperature range, the material's plasticity increases, reducing its yield strength and making it more susceptible to deformation during the drawing process. A drawing rate of 0.5 mm / s to 2 mm / s effectively controls the material's deformation rate, avoiding excessive stress concentration and improving the uniformity and precision of the initial forming. After drawing, the billet is gradually cooled to room temperature, which helps to fix the alloy's microstructure and enhance its mechanical properties.

[0020] In the second stage of drawing, the material is heated again to 600°C to 800°C. At this time, the material still maintains good plasticity and can be further reduced to 80%-90% of the target diameter at a drawing rate of 2 mm / s to 5 mm / s. The lower heating temperature in this stage helps to reduce the impact of heat treatment on the material, maintain appropriate hardness and toughness, and avoid excessive embrittlement. After cooling to room temperature, the microstructure is further stabilized, and the magnetic properties of the material are enhanced.

[0021] Finally, in the final drawing stage, the alloy billet is heated again to 600°C to 800°C, and after selecting a suitable drawing die, the final forming process is carried out. The temperature setting in this stage ensures the plasticity of the material. The use of a higher drawing rate (2 mm / s to 5 mm / s) can effectively shorten the drawing time and improve production efficiency. After completion, it is gradually cooled to room temperature to ensure the dimensional accuracy and performance stability of the final product. This step-by-step drawing not only optimizes the material's microstructure, but also improves the overall performance of the alloy, laying a good foundation for the final preparation of low-coercivity Wiegand wire.

[0022] Beneficial effects of the present invention:

[0023] 1. The mechanism of iron (Fe) in low-coercivity Wiegand wire is mainly reflected in its role as the main component of the alloy, providing basic magnetic and mechanical strength. Iron has excellent magnetic permeability and can effectively form and maintain magnetic domain structure, thereby improving the saturation magnetic induction intensity of the material. This strong magnetism enables iron to enhance the overall magnetic properties when combined with other alloying elements (such as nickel and cobalt). In addition, when iron is combined with elements such as aluminum, it can form a stable oxide layer, improving the alloy's oxidation resistance and corrosion resistance. At the same time, the low cost of iron makes it an economical choice for manufacturing low-coercivity Wiegand wire, further reducing the production cost of the material;

[0024] 2. The mechanism of nickel (Ni) in low-coercivity Wiegand wire is mainly reflected in its enhancement of the magnetic and mechanical properties of the material. As an important alloying element, nickel has good corrosion resistance and toughness, which can significantly improve the overall durability of the alloy. In terms of magnetic properties, nickel can optimize the magnetic domain structure and promote close coupling between magnetic domains, thereby reducing the movement resistance of the magnetic domain wall and reducing the coercive force. In addition, the alloying interaction formed by nickel and other elements (such as cobalt and aluminum) in the alloy can improve the saturation magnetic induction intensity of the alloy, so that the material exhibits better magnetic characteristics during application. At the same time, the addition of nickel can also improve the thermal stability of the material, ensuring that it maintains excellent performance in high-temperature environments. In summary, the weight percentage of Ni in the Wiegand wire prepared in this application is controlled at 10wt% to 15wt%;

[0025] 3. The mechanism of cobalt (Co) in low coercive force Wiegand wire is mainly reflected in its enhancement of the magnetic properties of the material and improvement of the mechanical strength of the alloy. Cobalt has a high saturation magnetic induction intensity, which can effectively improve the magnetic permeability of the alloy and enhance its overall magnetic properties. In addition, cobalt can optimize the arrangement and stability of the magnetic domains, thereby reducing hysteresis loss, which is crucial to reducing coercive force. The addition of cobalt can also improve the corrosion resistance and wear resistance of the alloy, making the material perform better in harsh environments. Through the synergistic effect with elements such as nickel and iron, cobalt can form a stable magnetic interaction, further enhancing the magnetic properties of the material. In addition, the presence of cobalt helps to regulate the crystal structure of the alloy, promote grain refinement, and reduce internal defects and stress concentration. In summary, the weight percentage of Co in the Wiegand wire prepared in this application is controlled at 3wt% to 7wt%;

[0026] 4. The mechanism of aluminum (Al) in low-coercivity Wiegand wire is mainly reflected in its improvement of the alloy's oxidation resistance and mechanical properties. The addition of aluminum can form a protective oxide film, improve the alloy's corrosion resistance, and thus extend the material's service life. In addition, the presence of aluminum helps promote grain refinement, enhance the material's toughness and strength, and reduce the risk of failure due to brittleness. Aluminum can also optimize the alloy's magnetism, by reducing magnetic defects and grain boundary resistance within the material, improving magnetic properties, thereby reducing coercivity. The interaction between aluminum and other alloying elements (such as nickel and cobalt) can form a stable alloy phase, further improving the overall magnetic properties. In summary, the weight percentage of Al in the Wiegand wire prepared in this application is controlled at 2wt% to 5wt%;

[0027] 5. The mechanism of silicon (Si) in low-coercivity Wiegand wire is mainly reflected in its improvement of the electrical conductivity and high-temperature resistance of the alloy. The addition of silicon can improve the magnetic permeability of the material and reduce the hysteresis loss caused by current loss, thereby effectively reducing the coercive force. In addition, silicon can optimize the microstructure of the alloy, promote grain refinement, reduce the influence of magnetic defects and grain boundaries, and thus improve the overall magnetic properties of the material. The presence of silicon in the alloy can also improve its oxidation resistance, enhance the stability of the alloy in a high-temperature environment, and reduce the performance degradation caused by high temperature. Through the interaction with elements such as iron, nickel and cobalt, silicon can promote the formation of a more uniform alloy phase, thereby optimizing the performance of the material. In summary, the weight percentage of Si in the Wiegand wire prepared in this application is controlled at 2wt% to 5wt%;

[0028] 6. The mechanism of manganese (Mn) in low-coercivity Wiegand wire is mainly reflected in its enhancement of alloy strength and improvement of magnetic properties. The addition of manganese can effectively improve the oxidation resistance and corrosion resistance of the alloy and reduce the performance degradation of the material in harsh environments. In addition, manganese can promote grain refinement and reduce internal stress and magnetic defects by reducing grain size, thereby optimizing the magnetic permeability of the material and reducing coercivity. Manganese can also form a stable alloy phase with elements such as iron, nickel and cobalt in the alloy, enhance magnetic interaction, and further improve the saturation magnetic induction intensity and overall magnetic properties of the material. At the same time, the presence of manganese helps to reduce the motion resistance of the magnetic domain wall, making the material more sensitive to the action of the magnetic field. In summary, the weight percentage of Mn in the Wiegand wire prepared by this application is controlled at 1wt% to 3wt%;

[0029] 7. The mechanism of titanium (Ti) in low-coercivity Wiegand wire is mainly reflected in its enhancement of the strength of the alloy and improvement of corrosion resistance. The addition of titanium can effectively improve the material's oxidation resistance and form a stable titanium oxide layer, thereby protecting the alloy from erosion by environmental factors. In addition, titanium has high strength and stiffness, which can improve the overall mechanical properties of the alloy and enhance the stability of the material under load. Titanium also plays a role in refining grains in the alloy, reducing defects and stress concentration inside the material, thereby optimizing magnetic properties and reducing coercivity. At the same time, the presence of titanium helps to improve the thermal stability of the alloy, so that the material maintains good performance in high-temperature applications. In summary, the weight percentage of Ti in the Wiegand wire prepared in this application is controlled at 0.5wt% to 2wt%;

[0030] 8. The mechanism of aluminum oxide (Al2O3) in reducing coercivity and increasing saturation magnetic induction intensity is mainly reflected in the following aspects. First, nano-scale Al2O3 particles can be evenly distributed in the alloy matrix to form a large number of interfaces. Due to the existence of these interfaces, the magnetic domain wall will be hindered in the process of movement, which will play a pinning effect, thereby effectively reducing the movement range and energy loss of the magnetic domain wall, thereby reducing the coercivity. In addition, the introduction of Al2O3 particles can refine the grain structure of the alloy. The fine grains increase the number of grain boundaries, and the pinning effect of the grain boundaries on the magnetic domain wall is further strengthened, making the movement of the magnetic domain wall more difficult. This not only helps to reduce the coercivity, but also improves the alloy under external Stability under magnetic field; on the other hand, the dispersed phase effect of Al2O3 can optimize the microstructure of the alloy, reduce the generation and aggregation of internal defects, and reduce the internal stress of the material, which helps to reduce hysteresis and enable the material to reach magnetic saturation under a lower external magnetic field, thereby increasing the saturation magnetic induction intensity. Nano-scale Al2O3 particles can also improve the mechanical strength and thermal stability of the material. This enhancement makes the alloy more stable under high magnetic fields and can maintain high magnetic properties without microstructural collapse. In summary, the weight percentage of Al2O3 in the preparation of Wiegand wire in this application is controlled at 2wt% to 5wt%, and the particle size range of the particles is 100 nm to 500 nm;

[0031] 9. The mechanism of cerium (Nd) in reducing the coercive force of the alloy is mainly reflected in its ability to enhance magnetic interaction and improve the microstructure. Nd has high magnetic permeability and good magnetic stability. Its addition can increase the saturation magnetic induction intensity of the alloy, making the arrangement of magnetic domains more orderly. This orderly arrangement reduces hysteresis loss, thereby effectively reducing the coercive force. In addition, the presence of Nd promotes the refinement of alloy grains, reduces internal defects and stress concentration, and further optimizes the magnetic properties of the material. At the same time, Nd can form a stable alloy phase with other alloying elements (such as iron, nickel and cobalt), improve the overall strength and toughness of the alloy, and reduce magnetic loss caused by changes in the external magnetic field. In summary, the weight percentage of Nd in the Wiegand wire prepared in this application is controlled at 0.2wt% to 0.6wt%;

[0032] 10. The synergistic effect between nickel (Ni), cobalt (Co), and aluminum (Al) plays a crucial role in low-coercivity, high-saturation magnetic flux density Wiegand wire. Nickel increases the alloy's saturation magnetic flux density and permeability, forming a stable magnetic phase with other elements (such as cerium and Nd), enhancing the orderly arrangement of magnetic domains, thereby reducing hysteresis losses and lowering coercivity. Meanwhile, the introduction of cobalt, a high-quality soft magnetic material, not only improves the alloy's permeability and saturation magnetic flux density but also, together with nickel, promotes the formation of a uniform magnetic phase, enhances the stability of magnetic domains, and makes the material more sensitive to external magnetic fields. Aluminum plays a crucial role in this process. Its enhanced oxidation resistance and improved mechanical properties work synergistically with nickel and cobalt to promote grain refinement, reduce internal defects, and thus optimize the alloy's microstructure. Furthermore, the presence of aluminum improves the alloy's thermal stability, enabling the material to maintain excellent magnetic properties under a variety of environmental conditions. In summary, the synergistic effect between nickel, cobalt and aluminum ultimately achieves the goal of reducing coercivity by improving the microstructure and magnetic properties of the alloy, ensuring the reliability and effectiveness of Wiegand wire in high-performance applications; BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 This is the experimental data diagram of the Wiegand silk prepared in Example 5; DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0038] Example 1 provides a low coercive force Wiegand wire and a preparation method, wherein:

[0039] The components of Wiegand wire include, in percentage by weight: Ni 15wt%, Co 3wt%, Al 3wt%, Si 3wt%, Mn 1wt%, Ti 2wt%, Al2O3 2wt%, Nd 0.6wt%, and the balance is Fe and other inevitable impurities.

[0040] The preparation method of low coercive force Wiegand wire comprises the following preparation steps:

[0041] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio; wherein the particle size of the Al2O3 powder ranges from 100 nm to 300 nm;

[0042] S2. The weighed powders in step S1 were uniformly mixed in a planetary ball mill according to the proportions, and the mixed powders were melted in a vacuum induction furnace at a temperature set at 1450°C for 2 hours;

[0043] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 2 minutes;

[0044] S4. The quenched alloy billet was heated to 600°C and maintained at this temperature for 4 hours, and then naturally cooled to room temperature;

[0045] S5. Heat the alloy billet to 800°C and perform a preliminary drawing at a drawing rate of 0.5 mm / s until the billet reaches 60% of the target diameter. After the first stage of drawing, gradually cool the first drawn billet to room temperature.

[0046] The cooled alloy billet was reheated at 600°C and drawn in the second stage at a rate of 5 mm / s until the billet was drawn to 80% of the target diameter. After the second stage drawing, the billet was gradually cooled to room temperature.

[0047] The cooled alloy billet was reheated at 800°C, and a drawing die was selected. The final drawing was performed at a drawing rate of 2 mm / s until the billet was drawn to the target diameter. After the final drawing, the billet was gradually cooled to room temperature. During the drawing stage, a constant magnetic field of 100 mT was applied, and the direction of the magnetic field was consistent with the drawing direction.

[0048] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer. The pickling temperature is set at 50°C and the soaking time is 15 minutes. A 5 wt% sulfuric acid solution is used, followed by sandblasting.

[0049] Example 2 provides a low coercive force Wiegand wire and a preparation method, wherein:

[0050] The components of Wiegand wire include, in percentage by weight: Ni 13wt%, Co 4wt%, Al 3wt%, Si 4wt%, Mn 2wt%, Ti 0.5wt%, Al2O3 3wt%, Nd 0.4wt%, and the balance is Fe and other inevitable impurities.

[0051] The preparation method of low coercive force Wiegand wire comprises the following preparation steps:

[0052] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio; wherein the particle size of the Al2O3 powder ranges from 200 nm to 500 nm;

[0053] S2. The weighed powders in step S1 were uniformly mixed in a planetary ball mill according to the proportions, and the mixed powders were melted in a vacuum induction furnace at a temperature of 1600°C for 1 hour.

[0054] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 1 minute;

[0055] S4. The quenched alloy billet was heated to 800°C and maintained at this temperature for 4 hours, and then naturally cooled to room temperature;

[0056] S5. Heat the alloy billet to 1000°C and perform a preliminary drawing at a drawing rate of 2 mm / s until the billet reaches 70% of the target diameter. After the first stage of drawing, gradually cool the first drawn billet to room temperature.

[0057] The cooled alloy billet was reheated at 800°C and drawn in the second stage at a rate of 2 mm / s until the billet was drawn to 90% of the target diameter. After the second stage drawing, the billet was gradually cooled to room temperature.

[0058] The cooled alloy billet after the second drawing was reheated at 600°C. A drawing die was selected and a final drawing rate of 5 mm / s was used to draw the alloy billet to the target diameter. After the final drawing was completed, the alloy billet was gradually cooled to room temperature. When applying a magnetic field during the drawing stage, a constant magnetic field of 500 mT was used, and the direction of the magnetic field was consistent with the drawing direction.

[0059] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer. The pickling temperature is set at 60°C, the soaking time is 15 minutes, and a 10 wt% sulfuric acid solution is used. Then, sandblasting is performed.

[0060] Example 3 provides a low coercive force Wiegand wire and a preparation method, wherein:

[0061] The components of Wiegand wire include, in percentage by weight: Ni 10wt%, Co 7wt%, Al 5wt%, Si 3wt%, Mn 3wt%, Ti 1wt%, Al2O3 5wt%, Nd 0.2wt%, and the balance is Fe and other inevitable impurities.

[0062] The preparation method of low coercive force Wiegand wire comprises the following preparation steps:

[0063] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio; wherein the particle size of the Al2O3 powder ranges from 100 nm to 400 nm;

[0064] S2. The weighed powders in step S1 were uniformly mixed in a planetary ball mill according to the proportions, and the mixed powders were melted in a vacuum induction furnace at a temperature set at 1500°C for 1 hour;

[0065] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 1 minute;

[0066] S4. The quenched alloy billet was heated to 700°C and maintained at this temperature for 4 hours, and then naturally cooled to room temperature;

[0067] S5. Heat the alloy billet to 1000°C and perform a preliminary drawing at a drawing rate of 2 mm / s until the billet reaches 70% of the target diameter. After the first stage of drawing, gradually cool the first drawn billet to room temperature.

[0068] The cooled alloy billet was reheated at 700°C and drawn in the second stage at a rate of 4 mm / s until the billet was drawn to 85% of the target diameter. After the second stage drawing, the billet was gradually cooled to room temperature.

[0069] The cooled alloy billet after the second drawing was reheated at 600°C. A drawing die was selected and a final drawing rate of 5 mm / s was used to draw the alloy billet to the target diameter. After the final drawing was completed, the alloy billet was gradually cooled to room temperature. When applying a magnetic field during the drawing stage, a constant magnetic field of 100 mT was used, and the direction of the magnetic field was consistent with the drawing direction.

[0070] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer. The pickling temperature is set at 60°C and the soaking time is 15 minutes. An 8 wt % sulfuric acid solution is used, followed by sandblasting.

[0071] Example 4 provides a low coercive force Wiegand wire and a preparation method, wherein:

[0072] The components of Wiegand wire include, in percentage by weight: Ni 13wt%, Co 7wt%, Al 2wt%, Si 1wt%, Mn2wt%, Ti 1wt%, Al2O3 3wt%, Nd 0.6wt%, and the balance is Fe and other inevitable impurities.

[0073] The preparation method of low coercive force Wiegand wire comprises the following preparation steps:

[0074] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio; wherein the particle size of the Al2O3 powder ranges from 200 nm to 400 nm;

[0075] S2. The weighed powders in step S1 were uniformly mixed in a planetary ball mill according to the proportions, and the mixed powders were melted in a vacuum induction furnace at a temperature set at 1600°C for 2 hours;

[0076] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 1 minute;

[0077] S4. The quenched alloy billet was heated to 800°C and maintained at this temperature for 4 hours, and then naturally cooled to room temperature;

[0078] S5. Heat the alloy billet to 1000°C and perform a preliminary drawing at a drawing rate of 1 mm / s until the alloy billet is drawn to 60% of the target diameter. After the first stage of drawing is completed, gradually cool the first drawn alloy billet to room temperature.

[0079] The cooled alloy billet was reheated at 800°C and drawn in the second stage at a rate of 4 mm / s until the billet was drawn to 80% of the target diameter. After the second stage drawing, the billet was gradually cooled to room temperature.

[0080] The cooled alloy billet was reheated at 600°C, and a drawing die was selected. The final drawing was performed at a drawing rate of 5 mm / s until the billet was drawn to the target diameter. After the final drawing, the billet was gradually cooled to room temperature. During the drawing stage, a constant magnetic field of 400 mT was applied, and the direction of the magnetic field was consistent with the drawing direction.

[0081] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer. The pickling temperature is set at 60°C, the soaking time is 15 minutes, and a 10 wt% sulfuric acid solution is used. Then, sandblasting is performed.

[0082] Example 5 provides a low coercive force Wiegand wire and a preparation method, wherein:

[0083] The components of Wiegand wire include, in percentage by weight: Ni 12wt%, Co 6wt%, Al 5wt%, Si 2wt%, Mn 3wt%, Ti 1wt%, Al2O3 4wt%, Nd 0.6wt%, and the balance is Fe and other inevitable impurities.

[0084] The preparation method of low coercive force Wiegand wire comprises the following preparation steps:

[0085] S1. Accurately weigh Fe-Ni alloy powder, Fe-Co alloy powder, Fe-Al alloy powder, Fe-Mn alloy powder, Fe-Ti alloy powder, Si powder, Al2O3 powder, and Fe powder according to the designed composition ratio; wherein the particle size of the Al2O3 powder ranges from 200 nm to 400 nm;

[0086] S2. The weighed powders in step S1 were uniformly mixed in a planetary ball mill according to the proportions, and the mixed powders were melted in a vacuum induction furnace at a temperature set at 1500°C for 2 hours;

[0087] S3. The molten metal is quickly poured into a mold preheated to 300°C and cooled for 1 minute;

[0088] S4. The quenched alloy billet was heated to 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, and 1000°C, and maintained at this temperature for 4 hours, and then naturally cooled to room temperature;

[0089] S5. Heat the alloy billet to 800°C and perform a preliminary drawing at a drawing rate of 1 mm / s until the billet is drawn to 65% of the target diameter. After the first stage of drawing is completed, gradually cool the first drawn billet to room temperature.

[0090] The cooled alloy billet was reheated at 800°C and drawn in the second stage at a rate of 4 mm / s until the billet was drawn to 80% of the target diameter. After the second stage drawing, the billet was gradually cooled to room temperature.

[0091] The cooled alloy billet after the second drawing was reheated at 600°C. A drawing die was selected and a final drawing rate of 3 mm / s was used to draw the alloy billet to the target diameter. After the final drawing was completed, the alloy billet was gradually cooled to room temperature. When applying a magnetic field during the drawing stage, a constant magnetic field of 400 mT was used, and the direction of the magnetic field was consistent with the drawing direction.

[0092] S6. Pickling the drawn Wiegand wire to remove the surface oxide layer. The pickling temperature is set at 60°C, the soaking time is 15 minutes, and a 10 wt% sulfuric acid solution is used. Then, sandblasting is performed.

[0093] Comparative Example 1

[0094] The difference between this control example and Example 2 is that the particle size of the Al2O3 powder ranges from 500 um to 1000 um;

[0095] Comparative Example 2

[0096] The difference between this control example and Example 2 is that the Nd powder is replaced by an equal mass of Fe powder;

[0097] Comparative Example 3

[0098] The difference between this control example and Example 2 is that no magnetic field is applied during the drawing stage;

[0099] Comparative Example 4

[0100] The difference between this control example and Example 2 is that a constant magnetic field of 500 mT is applied during the drawing stage, and the direction of the magnetic field is perpendicular to the drawing direction;

[0101] Comparative Example 5

[0102] The difference between this control example and Example 2 is that the Al powder is replaced by Fe powder of equal mass;

[0103] Comparative Example 6

[0104] The difference between this control example and Example 2 is that Fe powder is used instead of Co powder with the same mass;

[0105] Comparative Example 7

[0106] The difference between this control example and Example 2 is that the Ni powder is replaced by Fe powder of equal mass;

[0107] Table 1 Wiegand silk composition ratio (wt%) of Examples 1 to 4 and Comparative Examples 1 to 7

[0108] project Ni Co Al Si Mn Ti <![CDATA[Al2O3]]> Nd Example 1 15 3 3 3 1 2 2 0.6 Example 2 13 4 3 4 2 0.5 3 0.4 Example 3 10 7 5 3 3 1 5 0.2 Example 4 13 7 2 1 2 1 3 0.6 Example 5 12 6 5 2 3 1 4 0.6 Comparative Example 1 13 4 3 4 2 0.5 3 0.4 Comparative Example 2 13.4 4 3 4 2 0.5 3 0 Comparative Example 3 13 4 3 4 2 0.5 3 0.4 Comparative Example 4 13 4 3 4 2 0.5 3 0.4 Comparative Example 5 13 4 0 4 2 0.5 3 0.4 Comparative Example 6 13 0 3 4 2 0.5 3 0.4 Comparative Example 7 0 4 3 4 2 0.5 3 0.4

[0109] The specific testing methods for coercivity (Hc) and saturation magnetic flux density (Bs) are as follows: During the testing process, the sample is first prepared to the appropriate shape and size to ensure compatibility with the test equipment. The sample is secured in the VSM sample holder and tested at a constant temperature. A gradually increasing external magnetic field is applied, starting from zero, until it reaches a set maximum value, and then gradually decreasing to a negative value. This process records the magnetic flux density of the sample at different magnetic field strengths.

[0110] By analyzing the relationship between magnetic induction and external magnetic field strength, the saturation magnetic induction (Bs) can be determined. This is the maximum magnetic induction that a sample can achieve under an external magnetic field. Simultaneously, by observing the sample's magnetic response when the magnetic field is reversed, the coercive force (Hc) can be determined. This is the reverse magnetic field strength required to restore the material's magnetic properties to zero after the external magnetic field is removed.

[0111] Table 2 shows the data of Examples 1 to 4 and Comparative Examples 1 to 7.

[0112] project Saturation magnetic induction intensity (Bs) / (emu / g) Coercivity (Hc) / (Oe) Example 1 182 6.8 Example 2 174 8.2 Example 3 175 7.5 Example 4 189 6.1 Comparative Example 1 142 28.4 Comparative Example 2 105 34.2 Comparative Example 3 104 33.4 Comparative Example 4 95 36.7 Comparative Example 5 108 32.4 Comparative Example 6 99 34.6 Comparative Example 7 97 35.4

[0113] From Examples 1 to 4 and Table 2, it can be seen that the saturation magnetic flux density of Examples 1 to 4 ranges from 174 emu / g to 189 emu / g, and the coercive force of Examples 1 to 4 ranges from 6.1 Oe to 8.2 Oe. The preparation process and composition of the present application can be used to prepare Wiegand wires with low coercive force while maintaining high saturation magnetic flux density.

[0114] Combining Example 2, Comparative Example 1 and Table 2, it can be seen that there are significant differences in saturation magnetic flux density and coercive force between Example 2 and Comparative Example 1. The saturation magnetic flux density of Example 2 is 174 emu / g and the coercive force is 8.2 Oe, while the saturation magnetic flux density of Comparative Example 1 is only 142 emu / g and the coercive force is as high as 28.4 Oe, since nano-scale Al2O3 particles can be evenly distributed in the alloy matrix, forming a large number of interfaces, the existence of these interfaces will hinder the movement of magnetic domain walls, resulting in a pinning effect, thereby effectively reducing the movement range and energy loss of the magnetic domain walls, and thus reducing the coercive force. In addition, the introduction of Al2O3 particles can refine the grain structure of the alloy. The fine grains increase the number of grain boundaries, and the pinning effect of the grain boundaries on the magnetic domain walls is further strengthened, making the movement of the magnetic domain walls more difficult. This not only helps to reduce the coercive force, but also improves the stability of the alloy under an external magnetic field. On the other hand, the dispersed phase effect of Al2O3 can optimize the microstructure of the alloy, reduce the generation and aggregation of internal defects, and reduce the internal stress of the material, which helps to reduce hysteresis and enable the material to reach magnetic saturation under a lower external magnetic field, thereby improving the saturation magnetic induction intensity.

[0115] Combining Example 2, Control Example 2 and Table 2, it can be seen that there are significant differences in saturation magnetic induction intensity and coercive force between Example 2 and Control Example 2. The saturation magnetic induction intensity of Example 2 is 174 emu / g and the coercive force is 8.2 Oe, while the saturation magnetic induction intensity of Control Example 2 is only 105 emu / g and the coercive force is as high as 34.2 Oe. Nd has high magnetic permeability and good magnetic stability. Its addition can increase the saturation magnetic induction intensity of the alloy and make the arrangement of magnetic domains more orderly. This orderly arrangement reduces hysteresis loss, thereby effectively reducing coercive force.

[0116] A combination of Example 2, Comparative Examples 3 to 4, and Table 2 shows that there are significant differences in saturation magnetic induction and coercive force between Example 2 and Comparative Examples 2 to 3. The saturation magnetic induction of Example 2 is 174 emu / g and the coercive force is 8.2 Oe, while the saturation magnetic induction of Comparative Example 3 is only 104 emu / g and the coercive force is as high as 33.4 Oe. The saturation magnetic induction of Comparative Example 4 is only 95 emu / g and the coercive force is as high as 36.7 Oe. When an external magnetic field is applied, the magnetic domains tend to rearrange along the direction of the magnetic field under the action of the magnetic field force. This orderly magnetic domain orientation makes the magnetic moment within the material more consistent and enhances the magnetic induction intensity. This effect is more significant when the magnetic field direction is consistent with the processing direction (such as the drawing direction) because the magnetic domains are more easily reoriented in accordance with the external magnetic field. At the same time, the external magnetic field reduces the energy barrier of the magnetic domain walls, making the magnetic domain walls easier to move, reducing the accumulation of internal stress and defects, and thus reducing the coercive force of the material.

[0117] Combining Example 2, Comparative Examples 5 to 7, and Table 2, it can be seen that there are significant differences in saturation magnetic flux density and coercivity between Example 2 and Comparative Examples 5 to 7. Example 2 has a saturation magnetic flux density of 174 emu / g and a coercivity of 8.2 Oe, while Comparative Example 5 has a saturation magnetic flux density of only 108 emu / g and a coercivity of 32.4 Oe. Comparative Example 6 has a saturation magnetic flux density of only 99 emu / g and a coercivity of 34.6 Oe. Comparative Example 7 has a saturation magnetic flux density of only 97 emu / g and a coercivity of 35.4 Oe. The synergistic effect between nickel (Ni), cobalt (Co), and aluminum (Al) plays an important role in the low-coercivity, high-saturation magnetic flux density Wiegand wire. Nickel has good magnetic permeability and toughness, which can optimize the magnetic domain structure and promote close coupling between magnetic domains. Cobalt has a high saturation magnetization and forms a stable magnetic phase with nickel, enhancing the orderly arrangement of magnetic domains and thus reducing hysteresis loss. The addition of aluminum helps refine the grain structure, reduce internal defects, and form a protective oxide film, improving the alloy's oxidation and corrosion resistance. Aluminum also alloys with nickel and cobalt, further optimizing the alloy's microstructure. The synergistic effect of these three elements profoundly improves the material's magnetic properties, ultimately achieving low coercivity and high saturation magnetic induction.

[0118] Combined with Example 5 and Figure 1It can be seen that when the heat treatment temperature is in the range of 600℃ to 800℃, the coercivity of the Wiegand wire is the lowest, the saturation magnetic induction intensity is the highest, and the magnetic properties are the best. In this temperature range, the grain size is moderate, the number of grain boundaries is appropriate, the internal stress and defects are effectively eliminated, and the magnetic phase is fully formed and evenly distributed. In this way, the movement of the magnetic domain wall is subject to moderate pinning, which is easy to reverse and not easy to be over-pinned, achieving low coercivity. At the same time, the optimization of the magnetic phase improves the saturation magnetic induction intensity; when the heat treatment temperature is too high, the grains grow excessively, the grain boundaries are reduced, the pinning effect of the magnetic domain wall is weakened, the coercivity increases, the elements are segregated and non-magnetic phases are formed, the saturation magnetic induction intensity decreases, the internal defects and elements are lost, and the magnetic properties are further weakened; when the heat treatment temperature is too low, the internal stress and defects cannot be eliminated, the magnetic domain wall is pinned, the coercivity increases, the favorable magnetic phase cannot be fully formed, the saturation magnetic induction intensity decreases, the diffusion of magnetic elements is restricted, and the magnetic phase is unevenly distributed.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A low coercive force Wiegand wire, characterized in that: The metallurgical composition includes, in percentage by weight: Ni 10wt% to 15wt%, Co 3wt% to 7wt%, Al 2wt% to 5wt%, Si 1wt% to 4wt%, Mn 1wt% to 3wt%, Ti 0.5wt% to 2wt%, Al2O3 2wt% to 5wt%, Nd 0.2wt% to 0.6wt%, and the balance is Fe and other inevitable impurities.

2. The low coercive force Wiegand wire according to claim 1, characterized in that: The composition includes, in percentage by weight: Ni 13wt%, Co 4wt%, Al 3wt%, Si 4wt%, Mn 2wt%, Ti 0.5wt%, Al2O3 3wt%, Nd 0.4wt%, and the balance is Fe and other inevitable impurities.

3. The low coercive force Wiegand wire according to claim 1, characterized in that: The composition includes, in percentage by weight: Ni 15wt%, Co 3wt%, Al 3wt%, Si 3wt%, Mn 1wt%, Ti 2wt%, Al2O32wt%, Nd 0.6wt%, and the balance is Fe and other inevitable impurities.

4. The low coercive force Wiegand wire according to claim 1, characterized in that: The composition includes, in percentage by weight: Ni 10wt%, Co 7wt%, Al 5wt%, Si 3wt%, Mn 3wt%, Ti 1wt%, Al2O35wt%, Nd 0.2wt%, and the balance is Fe and other inevitable impurities.

5. The low coercive force Wiegand wire according to claim 1, characterized in that: The composition includes, in percentage by weight: Ni 13wt%, Co 7wt%, Al 2wt%, Si 1wt%, Mn 2wt%, Ti 1wt%, Al2O33wt%, Nd 0.6wt%, and the balance is Fe and other inevitable impurities.

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