Search

Iron-based soft magnetic composites insulated with parylene C film were prepared via chemical vapor deposition polymerization, and their morphologies, magnetic properties, and corrosive resistance were investigated. Scanning electron microscopy and Fourier transform infrared spectrum confirmed that the surface of the iron particle was completely uniform insulated with parylene C, resulting in reducing the core loss of the synthetic compacts. The results show that compressed pressure has an important influence on the magnetic properties of the soft magnetic composites, enhance the magnetic induction value from 0.64 to 1.01 T and is obtained with increased the compressed pressure from 300 to 650 MPa. The loss separation results show that the hysteresis loss coefficient of 4 wt% parylene C insulated samples decreased from 1.743 to 1.657 and eddy current loss coefficient decreased from 0.019 to 0.012 as compared with uncoated compacts under the same compress pressure. The acid and salt corrosion resistance of the iron particles is apparently enhanced when the chemically stable parylene C layer was exited in the surface. [ABSTRACT FROM AUTHOR]

Iron-based soft magnetic composites with silicone resin coating have been designed to reduce the core loss and improve the magnetic properties of cores. The silicone resin serving as electrical insulating layer was modified by 3-glycidoxypropyltrimethoxy silane, and the effect of silicone resin content, coupling agent, annealing treatment, and thermal cycling on the magnetic properties of composites was investigated in the frequency range from DC to 150 kHz. The coated silicone resin insulating layer was characterized by scanning electron microscopy and energy dispersive spectroscopy. The results showed that the optimum coating content of silicone resin to attain the acceptable permeability and the minimum magnetic loss for the prepared composites is 4 wt%. The sample with silicone resin coat exhibited better DC-bias superposition characteristics compared to the uncoated sample, 6 wt% silicone resin coating sample have excellent percentage effective permeability (84.8%) under 50 Oe applied field. AC magnetic properties evaluated at 1 and 100 kHz do not vary with a 95% confidence interval with the number of thermal cycles; therefore, the properties of the silicone resin-insulating composites are stable under thermal cycling. [ABSTRACT FROM AUTHOR]