BSI PD IEC TR 63304:2021
$189.07
Permanent magnet (magnetically hard) materials. Methods of measurement of magnetic properties in an open magnetic circuit using a superconducting magnet
Published By | Publication Date | Number of Pages |
BSI | 2021 | 50 |
This Technical Report describes the general principle and technical details of the methods of measurement of the DC magnetic properties of permanent magnet materials in an open magnetic circuit using a superconducting magnet (SCM).
This method is applicable to permanent magnet materials, such as those specified in IEC 60404-8-1, the properties of which are presumed homogeneous throughout their volume.
There are two methods:
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the SCM-Vibrating Sample Magnetometer (VSM) method;
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the SCM-Extraction method.
This document also describes methods to correct the influence of the self-demagnetizing field in the test specimen on the demagnetization curve measured in an open magnetic circuit. The magnetic properties are determined from the corrected demagnetization curve.
NOTE These SCM-methods can determine the magnetic properties of permanent magnet materials with coercivity higher than 2 MA/m. The methods of measurement in a closed magnetic circuit specified in IEC 60404-5 can lead to significant measurement error due to saturation effects in the pole pieces of yoke for the magnetic materials with coercivity higher than 1,6 MA/m (see IEC 60404-5).
PDF Catalog
PDF Pages | PDF Title |
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2 | undefined |
4 | CONTENTS |
7 | FOREWORD |
9 | INTRODUCTION |
11 | 1 Scope 2 Normative references 3 Terms and definitions |
12 | Figures Figure 1 – Demagnetization curve J(H) |
13 | 4 General principle 4.1 Principle of the method Figure 2 – Schematic diagrams of the test apparatus |
14 | 4.2 Superconducting magnet (SCM) |
15 | 4.3 Magnetic field strength sensor (H sensor) 4.4 Magnetic dipole moment detection coil (M coil) Figure 3 – Schematic diagrams of the first order gradiometer coil |
16 | 4.5 Specimen rod and moving device 4.6 Measuring devices and the data processing device 5 Test specimen |
17 | 6 Preparation of measurement 6.1 Measurement of volume of the test specimen 6.2 Initial magnetization of the test specimen to saturation 7 Determination of magnetic polarization 7.1 Measurement of the magnetic dipole moment |
18 | 7.2 Determination of magnetic polarization |
19 | 8 Measurement of magnetic field 9 Calibration of the magnetic dipole moment detection coil (M coil) 10 Determination of demagnetization curve |
20 | 11 Demagnetizing field correction 11.1 General Figure 4 – Relationship between magnetic polarization and self-demagnetizing field |
21 | Figure 5 – Schematic diagram of the demagnetizing field correction |
22 | 11.2 Method A: Method using a demagnetizing factor determined by the shape of the test specimen only 11.3 Method B: Method using a demagnetizing factor determined by the shape and the magnetic susceptibility of the test specimen Tables Table 1 – Features of the demagnetizing field correction methodsin comparison with Method B |
23 | 11.4 Method C: Method using an inverse analysis considering the spatial distribution of the self-demagnetizing field strength in the test specimen 12 Determination of principal magnetic properties 12.1 Remanent magnetic polarization Jr Figure 6 – Conceptual diagram of the procedure of Method C |
24 | 12.2 Maximum energy product (BH)max 12.3 Coercivity (HcJ and HcB) 13 Reproducibility 14 Test report Table 2 – Reproducibility of the magnetic properties |
26 | Annex A (informative)SCM-Magnetometer method Figure A.1 – Schematic diagram of the test apparatusfor the SCM-Magnetometer method |
27 | Figure A.2 – Schematic diagrams of the test apparatus for the methodin a closed magnetic circuit in accordance with IEC 60404-5 |
28 | Annex B (informative)Effects of the test specimen dimensions Figure B.1 – Effects of test specimen dimensions on magnetic properties [Br, HcJ, HcB and (BH)max] for Nd-Fe-B sintered magnets with different coercivities |
29 | Annex C (informative)Superconducting magnets (SCMs) Table C.1 – Performance of SCMs |
30 | Figure C.1 – Typical cross-sectional structure of the ceramic SCM |
31 | Annex D (informative)Magnetic dipole moment detection coils (M coils) Figure D.1 – Schematic diagram of the second order gradiometercoil for the SCM-VSM method |
32 | Figure D.2 – Schematic diagram of the dependence of induced voltageon the position of the test specimen in the SCM-Extraction method |
33 | Annex E (informative/normative)Details of the demagnetizing field correction E.1 General E.2 Symbols |
34 | E.3 Method using a demagnetizing factor determined by the shape and magnetic susceptibility of the test specimen (Method B) Figure E.1 – Axes of a cuboid magnet |
36 | E.4 Method using an inverse analysis considering the spatial distribution of the self-demagnetizing field strength in the test specimen (Method C) |
37 | Figure E.2 – Conceptual diagram of the procedure of Method C |
38 | Figure E.3 – Flowchart of the procedure of Method C |
40 | Figure E.4 – Comparison of the demagnetization curves correctedusing demagnetizing field correction Methods A, B and C |
41 | Annex F (informative)Result of the international round robin test of magnetic properties of permanent magnets using the SCM-VSM and SCM-Extraction methods F.1 General F.2 Protocol of the RRT Table F.1 – Nominal values of coercivity |
42 | F.3 Result of the RRT Figure F.1 – Comparison of Jr measured by the laboratories Table F.2 – Participating laboratories and their employed measuring methods |
43 | Figure F.2 – Comparison of HcJ measured by the laboratories Figure F.3 – Comparison of (BH)max measured by the laboratories |
44 | Table F.3 – Comparison of magnetic properties measured by the laboratories |
45 | F.4 Reproducibility of the measurements Figure F.4 – Comparison of hysteresis loops measured by the laboratories |
46 | Figure F.5 – Relative standard deviation of Jr, HcJ and (BH)max Table F.4 – Comparison of the reproducibility |
47 | Bibliography |