Multifunctional FeSiAl Soft Magnetic Composites with Inorganic–Organic Hybrid Insulating Layers for High Mechanical Strength, Low Core Loss and Comprehensive Anti-Corrosion

Excellent soft magnetic performance, superior mechanical strength and good corrosion resistance ensures that soft magnetic composites can be applied in practice for a long time. It is difficult for single organic coating or inorganic coating to meet the multifunctional requirements of a high-performance magnetic core. In this work, inorganic-organic hybrid insulating layers have been designed, which integrates the complementarity of the single type of insulating materials. After 700°C annealing, FeSiAl cores (outer diameter × inner diameter × height= 33.02 × 19.94 × 10.67 mm) deliver a core loss as low as 118.9 mW/cm3 and effective permeability as high as 61.6 at 50 mT and 100 kHz, which is due to the synergistic insulation of the SiO2 layer, TiO2 layer and SiO2-TiO2 hybrid layer on the surface of FeSiAl powder. Furthermore, crush strength is up to 1012.5 N, which may be ascribed to the SiO2-TiO2 hybrid layer. FeSiAl cores display excellent corrosion resistance activity with a maximum polarization resistance of 25,830.86 Ω cm−2. The inorganic-organic hybrid insulating layer has implications for obtaining soft magnetic powder cores with high mechanical strength, low core loss and good corrosion resistance.