Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors

Sensors (Basel). 2016 Apr 21;16(4):569. doi: 10.3390/s16040569.

Abstract

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated.

Keywords: Nd-Fe-B permanent magnets; coercivity; impulse magnetization; magnetic induction; magnetic saturation; permanent magnets.