Nanokomposite magnetic material

A nanocomposite magnetic material was developed using iron nanoparticles with a diameter of less than 80 nm. The iron nanoparticles were mixed with a styrenic block copolymer using a Brabender Plasticorder batch mixer. After mixing, the resulting material was compacted in a hot press at a temperature of 180°C. Because it proved difficult to obtain an adequate packing density with the iron nanopowders in their original form, a procedure for modifying the surface of the nanoparticles was developed to improve wetting by the plastic melt. This procedure made it possible to achieve a packing density of about 40 vol%. The quality factor (Q) and the permeability (ì) of the compacted samples were measured at different frequencies using commercially-available ferrite plate and iron particles with an average diameter of approximately 30 ìm as the reference material. It was found that the quality factor Q at higher fre quencies was much higher in the nanocomposite magnetic material than in the reference material. At a frequency of 8.2 MHz the quality factor Q was 175 in the polymer nanocomposite and 400 in the commercial ferrite. When the frequency was increased to 200 MHz, the quality factor Q was 70 in the polymer nanocomposite and 3 in the commercial ferrite. The permeability of the nanocomposite material remained at an almost constant value of 11 as the frequency was increased from 8.2 MHz to 200 MHz while the permeability of the commercial ferrite material fell from 400 to 33 over the same frequency range. The results obtained show that nanotechnology has potential as a way of developing magnetic materials for use in high-frequency applications.