Magnetic and Electrical Properties of Iron-Based Soft Magnetic Composites with Silicone Resin Insulation Coating

This paper investigates the magnetic and electrical properties of iron silicone resin soft magnetic composites. Scanning electron microscopy, energy dispersive X-ray spectroscopy analysis, distribution maps and density measurements confirm that the particles surface layer contains a thin layer of silicone resin with complete coverage of powders surface. The thickness of silicone resin film is averagely 120nm according to the results of transmission electron microscopy. Magnetic measurements show that the silicone resin insulation has a greater heat resistance than the conventional phosphate insulation, which enables stress reliving during annealing at higher temperature (600°C) without a large increase in magnetic loss. The results of annealing at 600°C show that the electrical resistivity increased from 8μΩ·m for SOMALOYTM samples to 55μΩ·m for the silicone insulated composites produced in this work.