Potential of powder metallurgical methods to fabricate Fe-6.5Si soft magnetic components

Abstract

The soft magnetic Fe-6.5Si alloy is well known for its excellent soft magnetic properties but its usage is limited due to fabricational constrains by conventional methods. Powder metallurgical processing of Fe-6.5Si is possible by a variety of different methods shown here, sinter-based screen printing (SP), electron beam powder bed fusion (E-PBF) and field-assisted sintering (field-assisted sintering/spark plasma sintering, FAST/SPS). The microstructure of the components varies strongly by process and powder used which is directly influencing their soft magnetic properties. The correlation between powder properties and processing parameters on the structural and magnetic properties is established. Lowest coercivity ( H c = 7 A m−1) is achieved by E-PBF due to large grain size minimising hysteresis losses necessary for direct current applications. SP can provide sheets with low coercivity ( H c = 21 A m−1) and adjustable thickness reducing eddy current losses especially suitable for alternating current application at higher frequencies. FAST/SPS can be used for a large range of powder particle sizes which is suitable to tune the soft magnetic properties in a wide range between 40 and 210 A m−1.