WG 5 - TC 68/WG 5

IEC TR 63304:2021(E) 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:
– the SCM-Vibrating Sample Magnetometer (VSM) method;
– 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).

IEC 60404-5:2015 is available as IEC 60404-5:2015 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60404-5:2015 is to define the method of measurement of the magnetic flux density, magnetic polarization and the magnetic field strength and also to determine the demagnetization curve and recoil line of permanent magnet materials. This edition includes the following significant technical changes with respect to the previous edition:
- adaption of the measurement methods and test conditions to newly introduced magnetically hard materials with coercivity values HcJ higher than 2 MA/m;
- update of the temperature conditions to allow the measurement of new materials with high temperature coefficients.

IEC 60404-8-1:2015 specifies minimum values for the principal magnetic properties of, and dimensional tolerances for, technically important magnetically hard materials (permanent magnets). For information purposes only, this part of IEC 60404 provides values for the densities of the materials and the ranges of their chemical compositions. Some additional physical data and mechanical reference values concerning the magnetic materials are given for information and comparison purposes. This edition includes the following significant technical changes with respect to the previous edition:
a) recently developed anisotropic Sm-Fe-N bonded magnets are included;
b) high energy ferrites with La and Co as substituents are included.

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.

IEC/TR 62518:2009(E) describes the temperature behaviour of rare earth sintered magnets in detail for use in designing magnetic circuits exposed to elevated temperatures. The temperature behaviour of SmCo5, Sm2Co17 and Nd-Fe-B sintered magnets is described. The various changes of open circuit flux which can occur due to temperature are discussed in Clause 4. The long term stability of the magnets is discussed in Clause 5. The experimental procedures are described in Clause 6. Results of the measurements of the flux loss occurring at the ambient temperature after heating isothermally at 50 °C, 75 °C, 100 °C, 125 °C, 150 °C and 200 °C for up to 1000 h are given in Clause 7. The effect of length to diameter ratio (L/D) of the magnet samples and the influence of HcJ on the flux loss were also studied. The results are discussed in Clause 8. The data in this technical report was provided by the Institute of Electrical Engineers of Japan (IEEJ) and its subcommittees. This data has been gathered from the members of these sub-committees. The temperature stability correlated with the complex corrosion behaviour and the spin re-orientation phenomena at cryogenic temperatures will not be given in this technical report.

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.

Provides methods for measuring magnetically hard materials, at elevated temperatures. Magnetically hard materials (permanent magnet materials) are classified in IEC 60404-1 and their properties are specified in IEC 60404-8-1. The methods of measurement of the magnetic properties of magnetically hard materials at room temperature have been specified in IEC 60404-5 for closed magnetic circuits and in IEC 60404-7 for open magnetic circuits, respectively. The applications of magnetically hard materials are now expanding to elevated temperatures and it is therefore required to specify and guarantee the magnetic properties of these materials over their working temperature range. In IEC 60404-8-1 temperature coefficients of remanence (or saturation) and J-coercivity have been specified in addition to basic properties such as maximum magnetic energy product ((BH)max), remanence (Br), B-coercivity (HcB), J-coercivity (HcJ), recoil permeability (µrec) and density.