A device for measuring magnetic field strength based on potential difference method

Abstract

The invention discloses a device for measuring magnetic field strength based on a potential difference method, comprising a computer, an electrochemical workstation, an electromagnet control cabinet, a multimeter, an electrolytic cell, a first coil, a second coil, a first iron core, and a second iron core; the computer is connected to the electrochemical workstation, a corrosion solution, a working electrode, and a reference electrode are placed in the electrolytic cell, the electrolytic cell is placed between the first iron core and the second iron core, the surfaces of the working electrode and the reference electrode are parallel and opposite, the working electrode is located in the middle of the first iron core and the second iron core, the reference electrode is located outside the circumference of the first iron core and the second iron core, and the cross section of the first iron core and the second iron core is perpendicular to the surface of the working electrode. By detecting the potential difference between the working electrode and the reference electrode, the strength of the applied magnetic field can be obtained simply and quickly. The device of the invention has a simple structure, and the magnetic field strength can be measured with high precision using the device, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic field strength measurement, and in particular relates to a device for measuring magnetic field strength based on a potential difference method. Background Art

[0002] The role of magnetic field is reflected in many aspects of natural science and engineering applications. There are many methods for testing magnetic field, such as fluxgate method, Hall effect method, magnetoresistance effect method, magnetic resonance method, superconducting effect method, magneto-optical effect method, etc., which require special devices and instruments. They are all based on physical effects and require relatively professional equipment and instruments. It is difficult or inconvenient to test with general instruments.

[0003] The present invention proposes a method for measuring magnetic field strength based on magneto-electrochemical principles and potential parameters by studying the action rules and selectivity effects of magnetic fields on electrochemical reactions. The working principle of the present invention is based on magneto-electrochemical theory: the magnetic field affects the surface electrode reaction rate of a specific metal in an ionic oxidant solution by superimposing the Lorentz force effect, causing the electrochemical state of the metal, such as the electrode potential, to change. A suitable metal of the same type is selected as a working electrode and a reference electrode and placed in the same electrolytic cell to form a set of devices, equipped with an electrochemical workstation or a voltmeter, and the potential difference between the working electrode in the magnetic field and the reference electrode in the absence of a magnetic field is tested. The relationship between the potential difference and the magnetic field strength can be calibrated, and it can be used to measure the magnetic field strength by measuring the potential difference of the same metal double electrode system under a magnetic field of unknown strength. Summary of the invention

[0004] In order to solve the problems of the prior art and practicability, the purpose of the present invention is to develop a device for measuring magnetic field strength based on the potential difference method, by measuring the potential difference between the same metal electrode in the presence and absence of a magnetic field caused by an external magnetic field, a calibration curve is obtained for measuring the unknown magnetic field strength. The originality of the present invention mainly includes three points: 1) the magnetic field strength test principle based on the Lorentz force effect of the magnetic field on the solid-solution electrochemical reaction; 2) the method of converting the magnetic field strength measurement into a potential parameter measurement through an electrochemical system; 3) the measuring device is assembled with commonly used components, does not require a special reference electrode, and has potential for application promotion;

[0005] 4) Testing with two identical electrodes can eliminate the influence of external interference and improve test sensitivity and accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A device for measuring magnetic field strength based on a potential difference method comprises: a computer, an electrochemical workstation, an electromagnet control cabinet, a multimeter, an electrolytic cell, a first coil, a second coil, a first iron core, and a second iron core. The computer is connected to the electrochemical workstation. The electrolytic cell comprises a corrosion solution, a working electrode, and a reference electrode. The electrolytic cell is placed between the first iron core and the second iron core. The working electrode and the reference electrode are immersed in the corrosion solution. The surfaces of the working electrode and the reference electrode are parallel and opposite. The working electrode is located between the first iron core and the second iron core. The reference electrode is located outside the circumference of the first iron core and the second iron core. The cross sections of the first iron core and the second iron core are perpendicular to the surfaces of the working electrodes. The working electrode and the reference electrode are respectively connected to the electrochemical workstation and the multimeter. The electromagnet control cabinet is connected to the first coil and the second coil.

[0008] In the device for measuring magnetic field strength based on the potential difference method, the electrolytic cell is a rectangular electrolytic cell, and the thickness of the electrolytic cell is less than the distance between the first iron core and the second iron core.

[0009] In the device for measuring magnetic field strength based on the potential difference method, the electromagnet control cabinet controls the magnetic field strength generated by the first coil and the second coil by controlling the magnitude of the input current.

[0010] The device for measuring magnetic field strength based on the potential difference method uses two identical metal electrodes, one of which is used as a working electrode, and the area of ​​the working electrode is less than or equal to 1 cm 2 , one as the reference electrode, after surface treatment, is placed in a rectangular electrolytic cell to form a double electrode system, in which the working electrode is placed in the middle of the magnetic field, and the reference electrode is far away from the magnetic field. The working electrode and the reference electrode need to be kept at a distance to ensure that there is a certain strength of magnetic field at the center of the two poles of the magnet when the working electrode is placed, and the magnetic field strength at the position of the reference electrode is almost negligible compared with the position of the working electrode. The working electrode and the reference electrode are on the same horizontal line.

[0011] The working electrode and reference electrode of the two-electrode system are immersed in a solution containing oxidant ions, and the potential difference between the two electrodes is continuously monitored and tested by an electrochemical workstation or a multimeter. When there is no magnetic field, the potential difference is close to 0.

[0012] Move the working electrode in the two-electrode system with a potential difference close to 0 to the middle of the first iron core and the second iron core with calibrated strength, and the distance from the center of the working electrode to the first iron core and the second iron core is equal. During the open circuit potential measurement process, the working electrode and the reference electrode are in a static state. The open circuit potential difference is measured, and the open circuit potential difference between the working electrode and the reference electrode under no magnetic field conditions under different magnetic field strengths is continuously measured. The magnetic field strength is 0.02-0.5T, and the magnetic field strength is gradually applied from small to large. The potential difference value reaches stability under each magnetic field condition. According to the electrode potential values ​​of the working electrode under different magnetic field strengths and the reference electrode under 0T measured by the electrochemical workstation after reaching steady state, the potential difference obtained under each magnetic field strength does not exceed 10%, and a standard curve of potential difference ΔE (X axis)-magnetic field strength B (Y axis) under magnetic field is drawn.

[0013] The same electrode system is placed in a magnetic field of unknown magnetic field strength to measure the difference between the working electrode and the reference electrode at 0T. The corresponding magnetic field strength value is obtained by drawing a standard curve. The deviation of the magnetic field strength corresponding to each potential difference is less than or equal to 10%.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention provides a device for measuring magnetic field strength, which measures magnetic field strength based on magneto-electrochemical principle and potential parameters, does not require professional equipment and instruments, and is simple and quick. The device of the present invention has a simple structure, is easy to operate, and uses the device to measure magnetic field strength with high accuracy, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 (a) is a schematic diagram of the structure of the device for measuring magnetic field strength based on the potential difference method of the present invention. Figure 1 (b) is a side view of the electrolytic cell of the device for measuring magnetic field strength based on the potential difference method of the present invention, which shows the positional relationship between the working electrode and the iron core and the connection method with the electrochemical workstation and the multimeter.

[0017] Figure 1 a: 1. Computer, 2. Electrochemical workstation, 3. Electromagnet control cabinet, 4. Multimeter, 5. Electrolytic cell, 6-1. First coil, 6-2. Second coil, 7-1. Second iron core, 7-2. Second iron core.

[0018] Figure 1 b: 2. Electrochemical workstation, 4. Multimeter, 5. Electrolytic cell, 7-1 first iron core, 7-2 second iron core, 8. Corrosion solution, 9. Working electrode, 10. Reference electrode.

[0019] Figure 2 This is the magnetic field strength curve measured using the device. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example: A curve of measuring the applied magnetic field strength by measuring the potential difference between two pure iron electrodes in a 0.12 mol / L ferric sulfate solution.

[0022] The device of the present invention is as follows Figure 1As shown, it includes: a computer 1, an electrochemical workstation 2, an electromagnet control cabinet 3, a multimeter 4, an electrolytic cell 5, a first coil 6-1, a second coil 6-2, a first iron core 7-1, and a second iron core 7-2. The computer 1 is connected to the electrochemical workstation 2. The electrolytic cell 5 includes a corrosion solution 8, a working electrode 9, and a reference electrode 10. The electrolytic cell is placed between the first iron core 7-1 and the second iron core 7-2. The working electrode 9 and the reference electrode 10 are immersed in the corrosion solution 8. The surfaces of the working electrode 9 and the reference electrode 10 are parallel and opposite. The working electrode 9 is located in the middle of the first iron core 7-1 and the second iron core 7-2. The reference electrode 10 is located outside the circumference of the first iron core 7-1 and the second iron core 7-2. The cross sections of the first iron core 7-1 and the second iron core 7-2 are perpendicular to the surface of the working electrode 9. The working electrode 9 and the reference electrode 10 are respectively connected to the electrochemical workstation 2 and the multimeter 4. The electromagnet control cabinet 3 is connected to the first coil 6-1 and the second coil 6-2. The electrolytic cell 5 is a rectangular electrolytic cell, and the thickness of the electrolytic cell is less than the distance between the first iron core 7-1 and the second iron core 7-2. The electromagnet control cabinet 3 controls the magnetic field strength generated by the first coil 6-1 and the second coil 6-2 by controlling the size of the input current. Two identical iron electrodes are used, one as a working electrode 9 and the other as a reference electrode 10. After being polished, they are placed in the rectangular electrolytic cell 5. The size of the electrolytic cell in the thickness direction needs to be suitable for being placed between the first iron core 7-1 and the second iron core 7-2 to form a double electrode system, wherein the working electrode 9 and the reference electrode 10 need to maintain a certain distance: the working electrode 9 can be placed between the first iron core 7-1 and the second iron core 7-2, and there is a magnetic field of a certain strength; while the reference electrode 10 is far away from the first iron core 7-1 and the second iron core 7-2, and the magnetic field strength at the position thereof can be ignored compared with the position of the working electrode 9. The double electrode system is connected to the electrochemical workstation (2) or the voltmeter (4) to form an electrochemical test system. The working electrode 9 and the reference electrode 10 of the dual-electrode system are immersed in a corrosion solution 8 containing oxidant ions, and the potential difference between the two electrodes is continuously monitored and tested by an electrochemical workstation 2 or a multimeter 4. The potential difference is close to 0 when there is no magnetic field. At the same time, the working electrode 9 in the dual-electrode system with a potential difference close to 0 is moved to the middle of the first iron core 7-1 and the second iron core 7-2 with calibrated strengths, and the reference electrode 10 is away from the magnetic field, and the open circuit potential difference between the working electrode 9 under the magnetic field and the reference electrode 10 without a magnetic field is measured. According to the open circuit potential values ​​of the working electrode 9 under different magnetic field strengths and the reference electrode 10 without a magnetic field measured in the corrosion solution 8 after reaching a steady state, a standard curve of open circuit potential difference (X axis) under a magnetic field-magnetic field strength (Y axis) is drawn. By using the same electrode system placed in a magnetic field of unknown magnetic field strength to measure the difference in open circuit potential between the working electrode 9 and the reference electrode 10 without a magnetic field, the corresponding magnetic field strength value can be obtained through the above-drawn standard curve.

[0023] Using the device of the present invention, an experimental test on iron in a 0.12 mol / L ferric sulfate solution was completed, and the test results are described as follows:

[0024] When there is no magnetic field at the working electrode, the potential difference between the working electrode and the reference electrode is close to 0. When 0.02T, 0.05T, 0.1T, 0.2T, 0.3T, 0.4T, and 0.5T magnetic fields are applied to the working electrode, the potential difference between the working electrode and the reference electrode is 0.35mV, 3.07mV, 7.29mV, 10.93mV, 13.27mV, 14.87mV, and 16.12mV, respectively. The potential difference (X axis)-magnetic field strength (Y axis) curve between the working electrode and the reference electrode is drawn. The experiment under the same conditions was repeated three times, and the maximum value of the potential difference fluctuation obtained under the condition of applying a 0.5T magnetic field was 0.93mV, and the variation range was 5.6%. The potential difference (X axis)-magnetic field strength (Y axis) curve between the working electrode and the reference electrode was fitted. When the potential difference deviation was 5.6%, the corresponding magnetic field strength deviation of the test was 9.6%. Therefore, in this system, when the working electrode is in an unknown magnetic field, if the potential difference between the working electrode and the reference electrode is measured to be 0.35mV, it can be judged that the working electrode is in a 0.02T magnetic field condition at this time. If the potential difference between the working electrode and the reference electrode is measured to be 3.07mV, 3.07mV, 7.29mV, 10.93mV, 13.27mV, 14.87mV, 16.12mV, it can be judged that the working electrode is in a 0.05T, 0.1T, 0.2T, 0.3T, 0.4T, 0.5T magnetic field condition at this time. Figure 2 shown.

Claims

1. A device for measuring magnetic field strength based on potential difference method, characterized in that The device comprises: a computer (1), an electrochemical workstation (2), an electromagnet control cabinet (3), a multimeter (4), an electrolytic cell (5), a first coil (6-1), a second coil (6-2), a first iron core (7-1), and a second iron core (7-2). The computer (1) is connected to the electrochemical workstation (2). The electrolytic cell is placed between the first iron core (7-1) and the second iron core (7-2). The electrolytic cell (5) comprises a corrosion solution (8), a working electrode (9), and a reference electrode (10). The working electrode (9) and the reference electrode (10) are immersed in the corrosion solution (8). The surfaces of the first and second iron cores (7-1 and 7-2) are parallel and opposite to each other, the working electrode (9) is located between the first iron core (7-1) and the second iron core (7-2), the reference electrode (10) is located outside the circumference of the first iron core (7-1) and the second iron core (7-2), the cross sections of the first iron core (7-1) and the second iron core (7-2) are perpendicular to the surface of the working electrode (9), the working electrode (9) and the reference electrode (10) are respectively connected to the electrochemical workstation (2) and the multimeter (4), the electromagnet control cabinet (3) is connected to the first coil (6-1) and the second coil (6-2); the working electrode (9) and the reference electrode (10) are two identical metal electrodes.

2. The device for measuring magnetic field strength based on the potential difference method according to claim 1, characterized in that: The electrolytic cell (5) is a rectangular electrolytic cell, and the thickness of the electrolytic cell is smaller than the distance between the first iron core (7-1) and the second iron core (7-2).

3. The device for measuring magnetic field strength based on the potential difference method according to claim 1, characterized in that: The area of ​​the working electrode (9) is less than or equal to 1 cm 2 .

4. The device for measuring magnetic field strength based on the potential difference method according to claim 1, characterized in that: During the open circuit potential measurement process, the working electrode (9) and the reference electrode (10) are in a stationary state.

5. The device for measuring magnetic field strength based on the potential difference method according to claim 1, characterized in that: The working electrode (9) is located in the middle of the first iron core (7-1) and the second iron core (7-2), and the distances from the center of the working electrode (9) to the first iron core (7-1) and the second iron core (7-2) are equal.

6. The device for measuring magnetic field strength based on the potential difference method according to claim 1, characterized in that: The working electrode (9) and the reference electrode (10) are on the same horizontal line.

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