Annealing device, annealing method and sensor for amorphous alloy

Abstract

The invention provides an annealing device and method for amorphous alloy and a sensor, and belongs to the technical field of preparation, the annealing device comprises a heating furnace, a closed heating cavity is formed in the heating furnace, and a heating body is arranged in the heating cavity; the containing pipe is located in the heating cavity, and a containing cavity is formed in the containing pipe and used for containing an annealing product; the alternating magnetic field generating part is fixedly arranged outside the heating furnace body, the alternating magnetic field generating part comprises an alternating current Helmholtz coil arranged around the containing pipe, and the alternating current Helmholtz coil is electrically connected with a power supply; the device has the advantages that the device combines dual functions of heating and magnetic field treatment, so that an annealed product is subjected to stable and uniform alternating magnetic field action in a high-temperature environment, thereby effectively improving the internal magnetic domain structure arrangement of a material, reducing the coercive force, improving the magnetic conductivity and obviously optimizing the soft magnetic performance of the material.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology, and particularly relates to an annealing apparatus, annealing method and sensor for amorphous alloys. Background Technology

[0002] Fluxgate sensors are widely used in weak magnetic field detection fields such as geological exploration, astronomical observation, and medical imaging due to their high sensitivity, low drift, wide frequency response, and strong anti-interference capability. As modern electronic devices develop towards miniaturization, integration, and low power consumption, more stringent requirements are placed on the size and power consumption of fluxgate sensors, posing new challenges to the performance of the core component—the magnetic core material—and its fabrication process.

[0003] Cobalt-based amorphous alloy wires and narrow-band materials, due to their near-zero magnetostriction coefficient, can significantly reduce hysteresis loss while maintaining good soft magnetic properties, making them ideal candidate materials for the cores of miniature fluxgate sensors. However, their final performance largely depends on the effect of the annealing process on the control of their microstructure and magnetic domain structure.

[0004] Currently, commonly used annealing methods include vacuum annealing, stress annealing, and static magnetic field-assisted annealing. The magnetic domain structure formed during annealing in a static magnetic field environment is difficult to adapt to the high-frequency excitation (typically exceeding 10kHz) operating conditions of fluxgate sensors. Under the influence of a high-frequency alternating magnetic field, the magnetic domain structure obtained through static annealing is prone to domain wall abrupt changes, introducing additional noise, leading to a decrease in the sensor's signal-to-noise ratio, and affecting its detection accuracy and stability. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing an alternating magnetic field-assisted annealing device.

[0006] The objective of this invention can be achieved through the following technical solution: an annealing apparatus for amorphous alloys, comprising:

[0007] A heating furnace, wherein a closed heating chamber is provided inside the heating furnace, and a heating element is provided inside the heating chamber;

[0008] A receiving tube is located inside the heating chamber, and the receiving tube is provided with a receiving cavity for receiving the annealed product;

[0009] An alternating magnetic field generator is fixedly installed outside the heating furnace body. The alternating magnetic field generator includes an AC Helmholtz coil arranged around the receiving tube, and the AC Helmholtz coil is electrically connected to a power supply.

[0010] In the above-mentioned annealing apparatus for amorphous alloys, the alternating magnetic field generating unit further includes an arbitrary waveform generator electrically connected to the AC Helmholtz coil. The arbitrary waveform generator is used to generate waveform signals such as square waves, sine waves, pulses, and sawtooth waves with frequencies of 1-100kHz. A power amplifier is electrically connected between the arbitrary waveform generator and the AC Helmholtz coil.

[0011] In the aforementioned annealing apparatus for amorphous alloys, the receiving tube is made of quartz.

[0012] In the above-mentioned annealing apparatus for amorphous alloys, openings are provided on both sides of the receiving tube, and a sealing cap is provided at each of the openings on both sides.

[0013] In the above-mentioned annealing apparatus for amorphous alloys, a support frame is provided at the bottom of the heating furnace, the receiving tube is arranged in a horizontal direction, and the receiving tube is located at the center of the AC Helmholtz coil.

[0014] In the above-mentioned annealing apparatus for amorphous alloys, there are two AC Helmholtz coils, the two AC Helmholtz coils are spaced 51 mm apart, and the length of the uniform magnetic field region generated is 37 mm.

[0015] In the above-mentioned annealing apparatus for amorphous alloys, heat insulation cotton is fixedly installed on the inner wall of the heating furnace.

[0016] In the above-mentioned annealing apparatus for amorphous alloys, the heating element includes a heating wire arranged around the receiving tube, the heating wire being electrically connected to a control power supply box, and the maximum heating temperature of the heating wire being 500°C.

[0017] An annealing method includes the following steps:

[0018] S1, set the parameters of the arbitrary wave generator to start it working;

[0019] S2, set the parameters of the power amplifier to start working to drive the AC Helmholtz coil to generate an alternating magnetic field;

[0020] S3, using an AC magnetic field sensor to measure the uniform magnetic field region at the center of an AC Helmholtz coil;

[0021] S4, turn on the temperature control box and heat up to the preset temperature;

[0022] S5. After the temperature stabilizes, place the amorphous alloy in the uniform magnetic field area through the sample rod, and after holding it at the temperature for a preset time, remove the amorphous alloy through the sample rod.

[0023] A sensor comprising an amorphous alloy, said amorphous alloy being prepared by the annealing method described above.

[0024] Compared with existing technologies, the advantages of this invention are as follows: By setting an AC Helmholtz coil as an alternating magnetic field generator outside the heating furnace and surrounding it around the receiving tube containing the annealed product, a uniform and controllable alternating magnetic field can be applied simultaneously during the annealing process. This device combines the dual functions of heating and magnetic field treatment, allowing the annealed product to be subjected to a stable and uniform alternating magnetic field at high temperatures, thereby effectively improving the internal magnetic domain structure arrangement of the material, reducing coercivity, increasing permeability, and significantly optimizing its soft magnetic properties. Attached Figure Description

[0025] Figure 1 This is a block diagram of the annealing apparatus.

[0026] Figure 2 This is one of the planar schematic diagrams of an annealing apparatus;

[0027] Figure 3 This is the second plan view of the annealing apparatus;

[0028] Figure 4 This is a comparison chart of sensor noise between the embodiment and the comparative example.

[0029] In the diagram, 100 is the heating furnace; 101 is the receiving tube; 102 is the protective shell; and 103 is the support frame. Detailed Implementation

[0030] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0031] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0032] like Figures 1-4 As shown, an alternating magnetic field annealing apparatus for amorphous alloys includes:

[0033] A heating furnace 100 is provided with a closed heating chamber, and a heating element is provided inside the heating chamber;

[0034] The receiving tube 101 is located inside the heating chamber, and the receiving tube 101 is provided with a receiving cavity for receiving the annealed product.

[0035] An alternating magnetic field generator is fixedly installed outside the heating furnace 100. The alternating magnetic field generator includes an AC Helmholtz coil arranged around the receiving tube 101, and the AC Helmholtz coil is electrically connected to a power supply.

[0036] In this embodiment, by setting an AC Helmholtz coil as an alternating magnetic field generator outside the heating furnace 100 and surrounding it around the receiving tube 101 containing the annealed product, a uniform and controllable alternating magnetic field can be applied simultaneously during the annealing process. This device combines the dual functions of heating and magnetic field treatment, allowing the annealed product to be subjected to a stable and uniform alternating magnetic field at high temperatures, thereby effectively improving the internal magnetic domain structure arrangement of the material, reducing coercivity, increasing permeability, and significantly optimizing its soft magnetic properties.

[0037] Furthermore, the alternating magnetic field generating unit also includes an arbitrary waveform generator electrically connected to the AC Helmholtz coil. The arbitrary waveform generator can generate waveform signals such as square waves, sine waves, pulses, and sawtooth waves with frequencies ranging from 1 to 100 kHz. A power amplifier is electrically connected between the arbitrary waveform generator and the AC Helmholtz coil.

[0038] In this embodiment, the arbitrary waveform generator can output a variety of controllable waveform signals with a frequency range of 1–100kHz, which can meet the diverse requirements of different materials for magnetic field form during the annealing process.

[0039] The signal output from the arbitrary waveform generator is amplified by a power amplifier and then used to drive a Helmholtz coil, generating a uniform, stable alternating magnetic field with specific frequency and waveform characteristics in the central region of the housing tube 101. This magnetic field can apply dynamic magnetization to functional materials such as amorphous alloys and nanocrystalline soft magnetic materials during the annealing process, effectively controlling their internal magnetic domain structure and improving the soft magnetic properties of the materials, such as reducing coercivity, increasing permeability, and optimizing hysteresis loss.

[0040] It is worth mentioning that the heating furnace 100 is provided with a protective shell 102 made of high-temperature resistant resin material, and the AC Helmholtz coil is installed inside the protective shell 102, so that it can operate stably in the high-temperature environment of the heating furnace 100.

[0041] Specifically, the receiving tube 101 is made of quartz, which has excellent high-temperature resistance, chemical stability, and electrical insulation properties. During high-temperature annealing, quartz can maintain structural stability at temperatures of 500℃ and above, and is not easily deformed or chemically reacted with the processed material, thereby effectively avoiding the introduction of impurities and surface contamination, and ensuring the purity and magnetic consistency of the annealed material (such as amorphous alloy wire, nanocrystalline ribbon, etc.).

[0042] Preferably, the receiving tube 101 has openings on both sides, and each opening has a sealing cap. Specifically, before annealing, the sample to be processed (such as amorphous alloy wire or amorphous alloy narrow strip) can be conveniently loaded into the receiving cavity from either side by opening the sealing cap, improving sample loading efficiency and operational convenience. During annealing, the sealing cap can provide sealing protection for the internal ring of the receiving tube 101, preventing external impurities from entering. At the same time, it supports the introduction of inert gas or atmosphere control methods such as evacuation through the openings, further improving the annealing quality and material performance stability.

[0043] Furthermore, the design with dual openings and a closed cap facilitates sample insertion and removal or connection to external detection equipment (such as temperature sensors, magnetic induction probes, etc.), enabling real-time monitoring of changes in physical and magnetic field parameters during the annealing process.

[0044] Further, the bottom of the heating furnace 100 is provided with a support frame 103, the receiving tube 101 is arranged in a horizontal direction, and the receiving tube 101 is located at the center of the AC Helmholtz coil.

[0045] Specifically, the receiving tube 101 is arranged horizontally and located at the center of the AC Helmholtz coil to ensure that the sample is in the region with the most uniform magnetic field, maximizing the magnetic field effect while reducing the impact of magnetic field inhomogeneity on the experimental results.

[0046] Specifically, there are two AC Helmholtz coils, spaced 51mm apart, producing a uniform magnetic field region 37mm long. The peak magnetic field at the center is 10Gs when the AC frequency is between 1-10kHz, and 1Gs when the frequency is between 10-100kHz. Continuous operation is possible. The power amplifier outputs a peak-to-peak current of 12A and a peak-to-peak voltage of 150V.

[0047] The heating furnace 100 has a length of 200 mm, an inner diameter of 20 mm, and an outer diameter of 95 mm. The heating element is 180 mm long, and the temperature control error is 5℃.

[0048] Preferably, the inner wall of the heating furnace 100 is fixedly equipped with heat-insulating cotton. This effectively reduces heat loss, improves heating efficiency, and helps maintain temperature stability within the heating chamber. The application of heat-insulating cotton not only reduces energy consumption but also reduces the influence of the external environment on the heating process, thereby ensuring that the sample remains under ideal temperature conditions throughout the annealing process. Simultaneously, the reduced temperature fluctuations indirectly improve the uniformity of the magnetic field and the consistency of annealing quality.

[0049] Further specifying, the heating element includes a heating wire arranged around the receiving tube 101, which is electrically connected to a control power supply box. The maximum heating temperature of the heating wire is 500°C. This heating wire is electrically connected to an intelligent control power supply box, enabling precise control of the heating process. This design not only ensures that heat is evenly distributed around the entire receiving tube 101, thus ensuring consistent temperature conditions for the sample during annealing, but also provides a flexible operating method and a reliable temperature management mechanism.

[0050] An annealing method includes the following steps:

[0051] S1, set the parameters of the arbitrary wave generator to start it working;

[0052] S2, set the parameters of the power amplifier to start working to drive the AC Helmholtz coil to generate an alternating magnetic field;

[0053] S3, using an AC magnetic field sensor to measure the uniform magnetic field region at the center of an AC Helmholtz coil;

[0054] S4, turn on the temperature control box and heat up to the preset temperature;

[0055] S5. After the temperature stabilizes, place the amorphous alloy in the uniform magnetic field area through the sample rod, and after holding it at the temperature for a preset time, remove the amorphous alloy through the sample rod.

[0056] Example:

[0057] S1, set the arbitrary wave generator to generate a sine wave with a frequency of 10kHz and a single peak value of 1.5V.

[0058] S2, set the parameters of the power amplifier to a magnification of 50 times;

[0059] S3, The parameter value of the uniform magnetic field region at the center of the Helmholtz coil measured by the AC magnetic field sensor is 10 Gs;

[0060] S4, turn on the temperature control box, set the heating rate to 280℃ at 10℃ / minute, and start the heat preservation process;

[0061] S5. After stabilizing at 280℃, place the amorphous alloy wire in the uniform magnetic field area through the sample rod, keep it at that temperature for 1 hour, and then remove the amorphous alloy wire through the sample rod.

[0062] Furthermore, the present invention provides a fluxgate sensor comprising an amorphous alloy wire obtained by the above-described preparation method, the noise result of which is as follows: Figure 3 As shown.

[0063] Comparative example:

[0064] Replace the arbitrary function generator in the embodiment with ordinary DC current to output a DC magnetic field of about 10 Gs, and the other steps are the same as in the embodiment.

[0065] The inventors conducted performance tests on the amorphous alloy wires prepared in the examples and comparative examples. The test results are as follows: As can be seen from the above results, the AC coercivity of the cobalt-based amorphous alloy wire prepared by the present invention and the amorphous alloy prepared in the comparative example is 0.5Oe.

[0066] Application Examples:

[0067] This application example provides a fluxgate sensor, comprising an amorphous alloy wire obtained by the preparation method of the example.

[0068] Application comparison:

[0069] This application provides a fluxgate sensor, comprising an amorphous alloy wire prepared by the comparative method, such as... Figure 4 As shown, the amorphous alloy prepared by the method of this invention, when applied to a sensor, optimizes wall shift smoothness through dynamic magnetic domain reconstruction, further reducing the noise of the fluxgate sensor and achieving a performance breakthrough. The noise of the heat treatment in this invention is 10.5 pT / √Hz@1Hz, while the comparative example is 55 pT / √Hz@1Hz.

[0070] It should be noted that in this invention, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0072] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. An annealing apparatus for amorphous alloys, characterized in that, include: A heating furnace, wherein a closed heating chamber is provided inside the heating furnace, and a heating element is provided inside the heating chamber; A receiving tube is located inside the heating chamber, and the receiving tube is provided with a receiving cavity for receiving the annealed product; An alternating magnetic field generator is fixedly installed outside the heating furnace body. The alternating magnetic field generator includes an AC Helmholtz coil arranged around the receiving tube, and the AC Helmholtz coil is electrically connected to a power supply.

2. The annealing apparatus for amorphous alloys according to claim 1, characterized in that, The alternating magnetic field generating unit also includes an arbitrary waveform generator electrically connected to the AC Helmholtz coil. The arbitrary waveform generator can generate waveform signals such as square waves, sine waves, pulses, and sawtooth waves with frequencies of 1-100kHz. A power amplifier is electrically connected between the arbitrary waveform generator and the AC Helmholtz coil.

3. The annealing apparatus for amorphous alloys according to claim 1, characterized in that, The container tube is made of quartz.

4. The annealing apparatus for amorphous alloys according to claim 1, characterized in that, The receiving tube has openings on both sides, and each opening on both sides is fitted with a sealing cap.

5. An annealing apparatus for amorphous alloys according to claim 1, characterized in that, The bottom of the heating furnace is provided with a support frame, the receiving tube is arranged horizontally, and the receiving tube is located at the center of the AC Helmholtz coil.

6. The annealing apparatus for amorphous alloys according to claim 1, characterized in that, The number of AC Helmholtz coils is two, the interval between the two AC Helmholtz coils is 51mm, and the length of the uniform magnetic field region generated is 37mm.

7. An annealing apparatus for amorphous alloys according to claim 1, characterized in that, Insulation cotton is fixedly installed on the inner wall of the heating furnace.

8. An annealing apparatus for amorphous alloys according to claim 1, characterized in that, The heating element includes a heating wire arranged around the receiving tube, the heating wire being electrically connected to a control power supply box, and the maximum heating temperature of the heating wire being 500°C.

9. An annealing method, characterized in that, Includes the following steps: S1, set the parameters of the arbitrary wave generator to start it working; S2, set the parameters of the power amplifier to start working to drive the AC Helmholtz coil to generate an alternating magnetic field; S3, using an AC magnetic field sensor to measure the uniform magnetic field region at the center of an AC Helmholtz coil; S4, turn on the temperature control box and heat up to the preset temperature; S5. After the temperature stabilizes, place the amorphous alloy in the uniform magnetic field area through the sample rod, and after holding it at the temperature for a preset time, remove the amorphous alloy through the sample rod.

10. A sensor, characterized in that, This includes amorphous alloys, which are prepared by the annealing method described in claim 9.

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