Micelle Preparation And Properties Of The Structure Of Metal / Ceramic Soft Magnetic Composite Materials

Magnetic materials have revolutionized our lives. These materials are used in electronic, computer and telecommunication industries. During the last decades different types of magnetic materials have been used including pure iron and its alloys and soft and hard ferrites. Different aspects of processing, properties, effect of additives on magnetic properties and applications of these ferrites were discussed by many researchers.New materials including amorphous materials, amorphous wires, nanocrystalline materials and today's soft magnetic composite materials are the latest development in magnetic history. It is worth reviewing the highlight of the magnetic materials development very briefly, before going to more details about soft magnetic composite materials.Ferromagnetic materials like Fe-based amorphous alloys and ferrites are well-known for high frequencies applications. Fe-based amorphous alloy have several advantages, such as high saturation magnetization and high effective permeability. However, the amorphous alloys are usually low-dimensional, such as thin films, sheets, powders, wires and rods due to the necessity of high cooling rate, which limit the possible applications. Unlike iron and iron-based alloys, which have low electrical resistivity, ferrites keep their magnetic properties unchanged due to high resistivity as many as megahertz ranges. The ferrites saturation magnetization as compared with ferromagnetic materials is relatively low results in limited application and performance.During the last several years, interest in the study of soft magnetic composites has been increasing at an accelerating rate. Soft magnetic composites (SMCs) can be described as ferromagnetic powder particles surrounded by an electrical insulating film, which are used in electromagnetic applications.In this thesis a new compound technique for SMCs:a bulk metal/ceramic soft magnetic composite material with a microcell structure was obtained by sintering spherical ferromagnetic alloy powders clad by soft magnetic ferrites nanopowder with spark plasma sintering technique. The asprepared material consisted of ferromagnetic alloy cell and closed ferrite ceramic cell wall.In this paper, the Fe76Si9B10P5/Zn0.5Ni0.5Fe2O4 bulk metal/ceramic soft magnetic composite material was obtained by sintering spherical Fe76Si9B10P5 glassy powders clad by Zn0.5Ni0.5Fe2O4 nanopowders with the SPS technique. SPS carried out below 487℃for 0 min and 600 MPa mechanical pressure. The resulting Fe76Si9B10P5 alloys in the composite still keep amorphous state and the relative density of the composite above 99.1%. The composite powders were consolidated into bulk through sintering them at 527℃under a pressure of 600 MPa for 6 min, while the Fe76Si9B10P5 in the composite with grain size of 30 nm nanocrystalline phase. These as-sintered samples with a diameter of 15×3 mm exhibited excellent soft magnetic characteristics, such as a three-dimensional (3D) isotropic ferromagnetic behavior, very low eddy current loss, relatively low total core loss at medium and high frequencies, superior corrosion resistance, and so on. Thus, the technique is beneficial for possible applications.