Magnetic and microstructural properties measurement and analysis of the smcs materials coated by double insulating layer

This work presents the study of the preparation routes of a soft magnetic composite (SMC) with an insulating iron-phosphate-resin coating. The energy losses of these composite materials in relation to the mobility of the domain walls during the magnetization process were studied. The SMC concept is based on the coating of magnetic particles with a surface layer, in the order of nanometers, electrically insulating and joined in the form of a three-dimensional matrix of a finished compact. The amount of phosphoric acid dissolved in the solvent should correspond to the desired coating thickness on the coated powder particles, where it was found that a suitable concentration of H3PO4 in 1 liter of acetone was 1/20 parts, to be added later 30 ml to 100 ml for 1000 grams of iron powder. The magnetic properties were investigated from the DC and AC hysteresis curve in the 0.05 Hz to 260 Hz frequency range and measured in relation to the contribution of the magnetic flux of the non-ferromagnetic components (pores and resin). The total losses were calculated from the area of the hysteresis loops, where the maximum values of 300, 420 and 600 W/m3 were found. The values of the maximum magnetic flux density Bm were around (0.82, 0.78 and 0.62 T), for frequencies of 1, 50 and 260 Hz, respectively.