Study of soft magnetic composites of iron coated with nanoparticles dispersion in liquid glass

This work presents the study and development of soft magnetic composites of iron coated with alumina nanoparticles dispersed in sodium silicate, also known as liquid glass. It is proposed that the nanoparticles dispersion increases the thermal resistance of the glassy coating, allowing a heat treatment with higher temperatures, reducing the internal stresses generated during the pressing and reducing core losses. Thermogravimetric analysis under an oxidative atmosphere of the powder samples and Scanning electron microscopy and energy-dispersive X-ray diffraction of fractured compacted samples are shown to discuss the coating thermal behavior. Also, electrical resistivity, relative permeability and magnetic losses of samples with and without nanoparticles dispersed in sodium silicate are shown discussing their loss separation.