Soft magnetic composites serve in electrical applications and sustainable energy supply, the magnetic flux changes in response to changes of the applied magnetic field, with energy loss. To reduce the loss, in this paper, the soft magnetic composite Fe 50 Ni 50 powder coated with nano-SiO 2 was prepared by tetraethoxysilane sol–gel method, and the microstructure of the coating was characterized. Then, soft magnetic Fe 50 Ni 50 powder cores have been prepared, and annealed with different atmospheres. The power loss is lower when the magnetic cores were annealed in a reducing hydrogen atmosphere. The lowest power loss (1390.7 mW/cm 3 , f = 1000 kHz, B = 50 mT, 120 °C) was obtained when the cores annealed at 730 °C in H 2 atmosphere. The results show that the eddy current loss is significantly reduced by coating SiO 2 , and the power loss is reduced about 33% in high-frequency (1 MHz and 50 mT, 25 °C). From 25 to 120 °C, the power loss at 1 MHz decreases by about 33% due to the reduction of hysteresis loss and eddy current loss. The excellent properties are very applicable for the inductors of 5G technology.
Currently, soft magnetic composites (SMCs) are usually used for high-current power devices. As a kind of SMCs, the FeSiAl magnetic powder core exhibits excellent magnetic properties, but it is difficult to improve its permeability and DC-bias characteristics. Thus, developing SMC s with high permeability and lower power loss remains a challenge. Here, the FeSiAl powder was mixed with carbonyl iron powder (CIP) which coated with nano-SiO 2 and pressed into toroidal magnetic core with silicon resin as adhesive. For MHz frequency, the SMCs with excellent power loss, saturation magnetization and permeability were obtained. Saturation magnetization of the mixed powder increased markedly with the CIP content increasing. For magnetic powder cores, the SEM and the mappings show that the large deformation CIP was helpful to improve core density. With the addition of CIP, the permeability and DC-bias properties were improved. In addition, the power loss was greatly reduced by the optimized annealing temperature.
危险品化学品经营许可证（带存储）