IEC TR 62517:2009

Magnetizing behaviour of permanent magnets

IEC/TR 62517:2009(E) describes the magnetizing behaviour of permanent magnets in detail covering:
- the relationship between the applied magnetic field strength and the effectively acting internal field strength;
- the initial state prior to magnetization;
- the magnetizing behaviour of all common types of permanent magnets subdivided according to the dominant coercivity mechanisms, namely the nucleation type for sintered Ferrites, RE-Fe-B and SmCo5 magnets, the pinning type for carbon steel and Sm2Co17 magnets and the single domain type for nano-crystalline RE-Fe-B, Alnico and Cr-Fe-Co magnets;
- the recommended magnetizing field strengths for modern permanent magnets compiled in a comprehensive table.

General Information

• Status: Published
• Publication Date: 06-Apr-2009
• 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-Jun-2009
• Completion Date: 07-Apr-2009

Standards Content (Sample)

IEC/TR 62517 ®
Edition 1.0 2009-04
TECHNICAL
REPORT
Magnetizing behaviour of permanent magnets

IEC/TR 62517:2009(E)
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IEC/TR 62517 ®
Edition 1.0 2009-04
TECHNICAL
REPORT
Magnetizing behaviour of permanent magnets

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
R
ICS 29.030 ISBN 978-2-88910-752-0
– 2 – TR 62517 © IEC:2009(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Effective magnetizing field strength .7
3 Initial magnetization state.8
4 Magnetizing behaviour of permanent magnets .8
4.1 General .8
4.2 Nucleation type magnets, sintered Ferrites, RE-Fe-B, SmCo .9
4.2.1 General .9
4.2.2 Initial magnetization curve after final heat treatment .9
4.2.3 Approach to saturation after final heat treatment .9
4.2.4 Coercivity mechanism of nucleation type magnets .11
4.2.5 Reversing the magnetization after magnetic saturation .12
4.3 Pinning type magnets, Sm Co .13
2 17
4.3.1 General .13
4.3.2 Initial magnetization curve .13
4.3.3 Approach to saturation .14
4.3.4 Coercivity mechanism of pinning type magnets.15
4.4 Single domain particle magnets.16
4.4.1 General .16
4.4.2 Single domain particle magnets based on magnetocrystalline
anisotropy .16
4.4.3 Alnico and CrFeCo magnets .16
5 Conclusions.17
Bibliography.19

Figure 1 – Principal magnetizing behaviour of RE-TM magnets after final heat
treatment .8
Figure 2 – Magnetizing behaviour of sintered Nd-Dy-Fe-B magnets .9
Figure 3 – Magnetizing behaviour of sintered Nd-Dy-Fe-B magnets with various
remanence B and coercivity H values after final heat treatment .11
r cJ
Figure 4 – Magnetizing behaviour of sintered Nd-Dy-Fe-B magnets with various
remanence B and coercivity H values after magnetic saturation in the reverse
r cJ
direction.12
Figure 5 – Magnetizing behaviour of sintered Sm Co magnets with a coercivity H of
2 17 cJ
about 800 kA/m.13
Figure 6 – Magnetizing behaviour of sintered Sm Co magnets with a coercivity H of
2 17 cJ
about 2 800 kA/m.14
Figure 7 – Magnetizing behaviour of sintered Sm-Co magnets with various remanence
B and coercivity H values, left: after final heat treatment and right: after magnetic
r cJ
saturation in the reverse direction .15
Figure 8 – Magnetization behaviour of bonded anisotropic HDDR RE-Fe-B magnets
compared to a sintered anisotropic RE-Fe-B magnet .16

TR 62517 © IEC:2009(E) – 3 –
Table 1 – The recommended internal magnetizing field strengths, H , to achieve
mag
complete saturation for modern permanent magnets, starting from the initial state after
the final heat treatment .18

– 4 – TR 62517 © IEC:2009(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIZING BEHAVIOUR OF PERMANENT MAGNETS

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62517, 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
68/377/DTR 68/384/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 62517 © IEC:2009(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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – TR 62517 © IEC:2009(E)
INTRODUCTION
The full performance of a permanent magnet can only be obtained if it is magnetized properly
to saturation. In IEC 60404-5 a definition of the saturation of a permanent magnet is given.
Accordingly, a magnet is defined as saturated at a magnetizing field strength H if a 50 %
higher field strength leads to an increase of (BH) or H of less than 1 %. However, such a
max cB
definition cannot explain the substantial differences in the magnetizing behaviour of modern
permanent magnets which is mainly determined by their coercivity mechanisms. Unfortunately
the variety of magnetizing behaviours cannot be accommodated by a simple recommendation
such as “magnetize with magnetizing field strengths of three to five times the coercivity H ”.
cJ
In particular for RE permanent magnets with high coercivity H this simplification would lead
cJ
to unacceptable overestimations of the required magnetizing field strengths.

TR 62517 © IEC:2009(E) – 7 –
MAGNETIZING BEHAVIOUR OF PERMANENT MAGNETS

1 Scope
It is within the scope of this technical report to describe the magnetizing behaviour of
permanent magnets in detail. Firstly, in Clause 3 the relationship between the applied
magnetic field strength and the effectively acting internal field strength is reviewed. In Clause
4 the initial state prior to magnetization is discussed. Then, in the main Clause 5, the
magnetizing behaviour of all common types of permanent magnets is outlined. The clause is
subdivided according to the dominant coercivity mechanisms, namely the nucleation type for
sintered Ferrites, RE-Fe-B and SmCo magnets, the pinning type for carbon steel and
Sm Co magnets and the single domain type for nano-crystalline RE-Fe-B, Alnico and Cr-
2 17
Fe-Co magnets. Finally, the recommended magnetizing field strengths for modern permanent
magnets are compiled in a comprehensive table.
2 Effective magnetizing field strength
For magnetization of permanent magnets, the internal magnetic field strength H in the
int
magnet is the critical parameter. T
...