IEC TR 62331:2005

Pulsed field magnetometry

Reviews methods for measuring magnetically hard materials using pulsed field magnetometers. The methods of measurement of the magnetic properties of magnetically hard materials have been specified in IEC 60404-5 for closed magnetic circuits and in IEC 60404-7 for open magnetic circuits. The measurement result of the magnetic properties of magnetically hard materials at elevated temperatures is given in IEC 61807. Pulsed field magnetometers have been developed to provide rapid measurement facilities to match high speed production rates with 100 % quality control. The object of this report is to describe the principles and practical implications of pulsed field magnetometry in order to enable the full potential of the technique to be considered, including its application using small and large magnets of varying geometries, to various magnetic field strengths and frequencies.

General Information

• Status: Published
• Publication Date: 22-Feb-2005
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Drafting Committee: WG 5 - TC 68/WG 5
• Current Stage: PPUB - Publication issued
• Start Date: 15-May-2005
• Completion Date: 23-Feb-2005

Standards Content (Sample)

TECHNICAL IEC
REPORT TR 62331
First edition
2005-02
Pulsed field magnetometry
Reference number
IEC/TR 62331:2005(E)
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TECHNICAL IEC
REPORT TR 62331
First edition
2005-02
Pulsed field magnetometry
 IEC 2005  Copyright - all rights reserved
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– 2 – TR 62331  IEC:2005(E)
CONTENTS
FOREWORD .4
INTRODUCTION .6

1 Scope and object.7
2 Normative references .7
3 Pulsed field magnetometer (PFM).7
3.1 General principles .8
3.2 Size of test specimen .10
4 Field generator.10
4.1 General .10
4.2 Power supply.10
4.3 Magnetizing solenoid.14
5 Polarization and magnetic field strength sensors (pick-up coils) .14
5.1 General .14
5.2 The polarization sensor (J coil).15
5.3 The magnetic field strength sensor (H coil) .16
6 Transient instrumentation and digitizing hardware.16
6.1 General .16
6.2 Analogue integration and digitization .17
6.3 Digitization and numerical integration .17
6.4 Digitization rate .17
7 Data processing .17
7.1 Data processing elements .18
7.2 Temperature.23
7.3 Magnetic viscosity .25
7.4 Calibration.25
8 Comparison of measurements .29
8.1 Permeameter, “large magnet“ comparison.29
8.2 Extraction method, ”small” test specimen comparison .30
8.3 Comparative measurement conclusions .33
9 Conclusion .33

Bibliography .34

Figure 1 – M’ and H time traces for a permanent magnet.9
Figure 2 – J(H) and B(H) loop for a permanent magnet .9
Figure 3 – Sine wave (decaying) electrical configuration .11
Figure 4 – Unidirectional pulses (1/2 sine wave) electrical configuration .12
Figure 5 – Unidirectional pulses (decaying) electrical configuration .12
Figure 6 –Three arrangements of J coil assembly configurations (drawing with
permission of EMAJ [ref. 30] .15
Figure 7 – M and H time traces and Φ(H) plot of a “zero signal” .19
Figure 8 – J(H) loops of a sintered NdFeB permanent magnet .23

TR 62331  IEC:2005(E) – 3 –
Figure 9 – J(H) loop including eddy currents of a conductive bulk nickel specimen
measurement result from a PFM system .27
Figure 10 – Copper specimen eddy current measurement result.27
Figure 11 – J(H) loop for eddy current “corrected” nickel specimen .28
Figure 12 – Results of a permeameter and a PFM measurement of a “large” specimen.29
st nd
Figure 13 – Detail of the 1 and 2 quadrants of the measurement results shown in
Figure 12 “large magnet” .29
Figure 14 – Comparison of a “small magnet” measured in a super-conducting,
extraction method magnetometer (EMM) compared with a PFM measurement result of
the same magnet [28] .30
Figure 15 – Measurement result of a NEOMAX 32EH NdFeB cylinder of diameter
10 mm length 7 mm on the TPM-2-10 system [34] .31
Figure 16 – Measurement result of a NEOMAX 32EH NdFeB cube of dimensions
7 mm × 7 mm × 7 mm [34].32
Figure 17 – Measurement result of a sintered Sm2Co17 cylinder of diameter 10 mm
and length 7 mm [34] .33

Table 1 – Comparison of methods of generating the magnetic field strength .13
Table 2 – Classification of the influences of eddy currents.21
Table 3 – A comparison of values taken from the measurement results presented in
Figure 11 and Figure 12.30
Table 4 – Comparison of values measured in Figure 14 above (see NOTE) .30

– 4 – TR 62331  IEC:2005(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PULSED FIELD MAGNETOMETRY
FOREWORD
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IEC 62331, which is a technical report, has been prepared by IEC technical committee 68:
Magnetic alloys and steels.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
68/299/DTR 68/303/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

TR 62331  IEC:2005(E) – 5 –
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
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A bilingual version of this publication may be issued at a later date.

– 6 – TR 62331  IEC:2005(E)
INTRODUCTION
In order to measure the full magnetic characterization of magnetically hard (permanent
magnet) materials, it is necessary to apply a magnetic field sufficient to saturate the test
specimen of magnetic material.
The generation of this magnetic field can become a practical limiting factor and can
determine the appropriate measurement techniques.
Super-conducting magnets can generate very h
...