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How to test the permeability of permalloy material u0.08 by scanning method?
Release time:
2022-09-09
Source:
Www.fe2100.com Hunan Yongyi Technology Co., Ltd.
Under the condition that the demagnetization control of the equipment is very good (the requirements of demagnetization quality should be added to the relevant IEC and GB standards), the initial permeability ui can be easily extrapolated by the impact method, and the Rayleigh constant of the material can be calculated more accurately. Similarly, the scanning method is used to test several sets of hysteresis loops under weak magnetic fields, take the corresponding maximum magnetic conductivity, and calculate the initial magnetic conductivity ui. This will fill the gap in the initial permeability test for DC magnetic properties measurement of soft magnetic materials. Finally, Hs are 8A/m, 0.8A/m and 0.08A/m three hysteresis loops together, the Rayleigh zone is very small!
First of all, explain the scanning method and the impact method test.magnetization curve.
Scanning method: if starting from the demagnetization state (0,0), the magnetic field strength is slowly increased in one direction, and the experienced magnetic state points (M,H) are connected to obtain the initial magnetization curve (or originmagnetization curve）。
Impact method: if starting from the demagnetization state (0,0), a stable symmetrical loop can be obtained by applying a given Hs step by step and performing magnetic exercise, and a basic magnetization curve (or normal magnetization curve) can be obtained by connecting the vertices (Ms,Hs) of these loops. Hysteresis loop under weak magnetic field: under the weak magnetic field near the demagnetization state, the symmetrical loop is generally leaf-shaped. Rayleigh first studied this phenomenon in 1887, so it is called Rayleigh zone. This loop is Rayleigh loop. In the Rayleigh region, the magnetic permeability of the material is: u(H1)= ui-u0H1, where ui is in the initial magnetic permeability, and is the Rayleigh constant in m/A. The magnetic susceptibility χ and the normal magnetic permeability of the material in the Rayleigh region are both linearly related to H, and the slope is and u0. In engineering, it is simple and convenient. For different materials, U under small field is used to replace the initial permeability ui. Generally, when ui is greater than 20k, high permeability material H takes 0.08A/m, and when ui is greater than 2k, it takes 0.8A/m, etc. It can be seen from the impact method measurement report that Hs reaching 0.08A/m has actually exceeded the Rayleigh zone of the material, and the position of the folding point is about 0.04A/m (see the following report).
The magnetization characteristics in the Rayleigh region can be further analyzed by using the original data tested by the impact method, and several points of H:0.01A/m ~ 0.04A/m can be selected according to the accuracy of the test equipment. The test results correspond to u0.01 = 52.374k,u0.04 = 57.035k. According to the relevant formula, the initial permeability ui = 50.358k and Rayleigh constant = 155400(m/A) can be obtained. This also shows that the deviation of u0.08 instead of initial permeability ui of 1J85 material is 24.69%, even if u0.04 is used instead of u, the deviation is 13.25%. Enterprises in the publicity equipment to test the uncertainty of the initial magnetic conductivity should indicate the test corresponding Hui, the real sense of the initial magnetic conductivity (refers to H close to 0) has not yet seen the source of the test method. The initial test point data of 1J85 material are shown in the following table for comparison. When u0.003 meets the requirements of H extrapolation to 0, the deviation and calculation reach the range of less than 1%.
| Hdat(A/m) |
Jdat(T) |
u（k） |
| 0.00198098 |
0.000126133 |
50.66928409 |
| 0.00298774 |
0.000190807 |
50.8215153 |
| 0.00399001 |
0.000258383 |
51.5330613 |
| 0.00498592 |
0.00032361 |
51.65027029 |
| 0.00599004 |
0.000390415 |
51.86718863 |
| 0.00698773 |
0.000453691 |
51.66780554 |
| 0.00798803 |
0.000524615 |
52.2633073 |
| 0.00899549 |
0.000591387 |
52.31699757 |
| 0.00999975 |
0.000658124 |
52.37384287 |
| 0.0199948 |
0.00136874 |
54.4752748 |
| 0.0299816 |
0.00209677 |
55.65335554 |
| 0.0399858 |
0.00286586 |
57.03538251 |
| 0.0500043 |
0.00369565 |
58.81369012 |
| 0.0599761 |
0.0045315 |
60.12547883 |
| 0.0699712 |
0.00540217 |
61.43891761 |
| 0.0799869 |
0.00631155 |
62.79305899 |
In some ferrite ui test conditions, the test conditions are 10kHz and Bm is less than 0.25mT (this condition almost meets all soft magnetic materials), which uses the reversible process under the loop weak field of the material without F dependence, but the prerequisite is that the sample needs to be demagnetized well first, and the voltage and current test resolution is accurate enough. In the case of poor demagnetization, ui repeatability will be poor, and the proposed uncertainty is roughly acceptable. 25%. The test frequency characteristic can be verified by scanning the hysteresis loop of 1J85 sample under the condition of frequency doubling (see the following figure). During the test, the spacing of scanning points is controlled to be 0.02s, 0.04 s and 0.08s respectively. The hysteresis loop obtained by three scans is superimposed on one figure to obtain u0.08 = 62.54k (taking the average value at three rates), this is basically equivalent to the u0.08 = 62.79K data tested by the impact method, that is, the frequency dependence in the weak field region can not be considered.
Therefore, under the condition that the demagnetization control of the equipment is very good (the requirements of demagnetization quality should be added to the relevant IEC and GB standards), the initial permeability ui can be easily extrapolated by the impact method, and the Rayleigh constant of the material can be calculated more accurately. Similarly, the scanning method is used to test several sets of hysteresis loops under weak magnetic fields, take the corresponding maximum magnetic conductivity, and calculate the initial magnetic conductivity ui. This will fill the gap in the initial permeability test for DC magnetic properties measurement of soft magnetic materials. Finally, Hs are 8A/m, 0.8A/m and 0.08A/m three hysteresis loops together, the Rayleigh zone is very small!
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Project Leader of Hunan Yongyi Technology Co., Ltd.: Engineer Zhu Yonghong |
In 1990, he graduated from the Department of Mathematics of Jilin University, majoring in Applied Mechanics, and was assigned to work in the Electronic Research Institute of Loudi City, Hunan Province. In 2000, he served as the director of Loudi Sanlian Magnetoelectric Research Institute, the general manager of Hunan Lianzhong Technology Co., Ltd. from 2003 to 2010, and since 2010Hunan Yongyi Technology Co., Ltd.General Manager. He has been engaged in the production organization and marketing of electromagnetic measuring instruments for many years. The main achievements are as follows:
1. patent (first inventor)
1. Dry pressing radial orientation magnetic field device, ZL 201620224572.2 (new type authorization date: July 27, 2016);
2. On-line magnetic powder measuring device for magnetorheological fluid, 201720167263.0 (new authorization date: 2016.8.02);
3. Basic hysteresis loop measuring device for soft magnetic materials, ZL 201620286407.X (new authorization date: 2016.8.24);
4. A three-dimensional magnetic field generating device, ZL 201510715986.5 (invention patent authorization date: 2017.4.12);
5. The method of measuring the basic hysteresis loop of soft magnetic materials by measuring device, 201610212992.3 (invention patent authorization date: 2019.3.6);
6, ferromagnetic cylindrical DC magnetic performance standard sample determination method, magnetic conductivity meter calibration method, 201810169642.2 (invention patent publication);
2. significant results:
1. Complete the magnetic field control design and manufacture of a mobile phone brand 7S shell magnetorheological fluid automatic 5-side polishing machine;
2. Complete the design and manufacture of the haimu holtz coil in the ultra-large space uniform area of the laser gyroscope experiment;
3. Complete the design and manufacture of 6 degrees of freedom high gradient magnetic field in the spherical space of the cardiac interventional magnetic navigation model;
4. Research on the test method of the basic hysteresis loop of the closed-circuit sample of soft magnetic material;
5. Design and manufacture of DC magnetic energy solenoid demagnetization correction method and magnetic permeability meter test method for soft magnetic material open circuit sample.
3. academic papers
1. Comparison and Suggestion of Measurement Methods for Magnetic Properties of Permanent Magnet Materials (2nd Author) "Magnetic Materials and Devices", 1001-3830(2015)05-0051-06; 2. Modeling of Temperature Effects on Magnetic Property of Nonoriented Silicon Steel Lamination (5th Author) "IEEE TRANSACTIONS ON MAGNETICS", VOL. 51, NO. 11, NOVEMBER 2015;
3. Research on Measurement Method and Measurement Device of Basic Hysteresis LoOP of Soft Magnetic Materials (First Author), Metal Functional Materials 1005-8192[2016]045;
4. The demagnetization correction of the magnetization curve and hysteresis loop measured by the solenoid method of cylindrical ferromagnetic samples (the second author), Proceedings of the 17th National Conference on Magnetism and Magnetic Materials, 2017.11;
5、Demagnetizing correction in fluxmetric measurements of magnetization curves and hysteresis loops of ferromagnetic cylinders（第3作者），《Journal of Magnetism and Magnetic Materials》 449 (2018) 447–454；
6、Calibration of a permeameter for measuring soft magnetic materials using long cylindrical samples characterized by demagnetizingcorrected solenoid method（第2作者），《Journal of Magnetism and Magnetic Materials》 458 (2018) 137–146；
7. demagnetization correction of relation curve of magnetization intensity to magnetic field of ferromagnetic cylindrical sample measured by flux meter solenoid method (2nd author), Metal Functional Materials 1005-8192[2018]04-0027-08.
8、Direct-current hysteresis loops of a MuMETAL ring measured by continuous recording and automatic ballistic methods ，IEEE MAGNETICS LETTERS, VOLUME 12 (2021) （第2作者）
9、Effective magnetic path length in Epstein frame test of electrical steels，Cite as: Rev. Sci. Instrum. 93, 055105 (2022);（第2作者）
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