Influence of resin type and content on electrical and magnetic properties of soft magnetic composites (SMCs)

The magnetic cores of rotating electrical machines, such as electric motors and generators, are generally made using laminated steel sheets. However, in certain types of special electrical machines, such as servomotors that operate at high frequencies, it is possible to construct these cores into single solid blocks using the Powder Metallurgy (P/M) process. The advantages of using P/M include lighter machines that consume less energy and perform better. Thus, this work aimed to conduct a comparative study on the electrical and magnetic properties of some soft magnetic composites made from iron powder combined with different phenolic resins: HRJ-10236, SBP-128, SP6600 and SP6601, with mass percentages varying from 0.5% to 3.0%. The influence of different resin contents on the magnetic properties of the composites was analyzed, including relative permeability, saturation induction and the losses, as well as the electrical resistivity. The best results recorded were: saturation induction of 0.64 T for the composite Fe–RA0.5, electrical resistivity of 5020 μΩ m for Fe–RC0.5, magnetic hysteresis losses of 0.45 W/kg for Fe–RB0.5 and total magnetic losses of 0.30 W at 1 kHz, 20% lower than in laminated steel cores.