Microstructure and magnetic properties of FeSiAl soft magnetic composites prepared by chemical in-situ coprecipitation with NaOH

Abstract

The FeSiAl powder was dispersed into NaOH solution with 10 wt% concentration, after a certain time then NaHCO3 with 2 wt% concentration was added. After calcination at 1250 °C, the coating changed into the oxide insulation on the surface of FeSiAl particles. The microstructure, formation mechanism, and magnetic properties of the coated powder prepared by the chemistry in-situ generation method has been investigated. The electrical insulation layer oxide was confirmed that there existence of Al2O3 phase. The thickenss of coating layer was about 20 nm measured by the TEM. The saturation magnetization (Ms) of FeSiAl powder slightly increased after coated, but obviously increased after calcined. Then the FeSiAl resistivity obviously increased after coated, and further increased after calcination. The FeSiAl soft magnetic composite has the magnetic properties of effective permeability μe = 56.03 and total magnetic loss Pcv = 1042.86 mW/cm3 that measured under the condition of frequency 1000 kHz and 20 mT. This is an effective method to prepare high performance FeSiAl@Al2O3 soft magnetic composite applied at higher frequency.