IEC/TR 61807 (1999-10)

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.