Measuring of Hard Magnetic Materials

The exact determination of the magnetic flux density of a homogeneous magnetic field is the basis of all calibrations in international magnetic bureaus of standards, as for example the PTB (Physikalisch Technische Bundesanstalt) in Braunschweig or the NPL (National Physical Laboratory) in London. Also BROCKHAUS uses this technology to calibrate with a very high accuracy magnetic properties like flux density and field strength as well as measuring instruments and coil systems. The nuclear magnetic resonance instrument (NMR) measures the frequency of a precision movement magnetic moments of protons produce, if they are exposed to a magnetic field.

This frequency is measured over a resonance circuit. As this frequency is coupled strictly linear to the strength of the magnetic field, the magnetic flux density or field strength can be determined with an accuracy of 10-6 T using this method.

Test MethodMeasuring coilMaterialField StrengthStandard
Material testing of hard
magnets in an
electromagnet
Compensated surrounding coilsFerrite
AlNiCo
Rare Earth
max. 2500 KA/mIEC 404-5
Pole coilsFerritemax. 2500 KA/m
Calibration of hard magnetic measuring equipmentCompensated surrounding coilsFerrite
AlNiCo
Rare Earth
max. 2500 KA/mIEC 404-5
Pole coilsFerritemax. 2500 KA/m
Calibration of
reference samples
Compensated surrounding coilsNickelmax. 1500 KA/m
Test MethodMeasuring coilPropertiesField StrengthStandard
Kalibrierung von
magnetischen Messgeräten
FluxmeterMagnetic fluxmax. 1500 KA/m Kernspin-
resonanz
Nuclear magnetic resonance (NMR)
GaussmeterField strength H
Flux density B
Polarisation J
max. 1500 KA/m Kernspin-
resonanz
NMR
Hall sensorsField strength H
Flux density B
Polarisation J
max. 1500 KA/m Kernspin-
resonanz
NMR
Helmholtz coilsCoil constant kReference
magnet/
NMR
Field coilsCoil area Amax. 1500 KA/m Kernspin-
resonanz
NMR