Structure And Magnetic Properties Of Nanocrystalline Fe-Co-Cu-Mo-Si-B Soft Magnetic Alloy

With the development of electronic industry,information and communication, there are more demands both in quantity and in quality to those which have good and compositive properties. For example, high resistance to reduce eddy current loss related to frequency, high Curie temperature and magnetization in high-temperature work environment. Fe-Cu-M-Si-B(M=Nb,Mo,V) series of alloys given extensive attention which have high permeability and saturation magnetization, near-to-zero magnetostriction have replaced many magnetic materials such as permalloy, ferrite in many applied fields. But lower Curie temperature and higher core loss in high frequency have restricted their applied ranges. On the base of Fe-Cu-Mo-Si-B alloy, we got (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ alloy by substituting Co for Fe partially. And then their properties at high temperature and high frequency were researched.1. The microstructure properties for (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ alloy annealed at different temperatures were studied. Changing annealing temperatures has great influence on microstructure of (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ soft magnetic alloy. Phase structure of the alloy was analyzed by X-ray diffraction. Annealed above the initial crystallization temperature, ultrafine grains of bcc FeCo(Si) phase were embedded in a residual amorphous matrix. With the increase of annealing temperature,the ordered Fe3Si and Fe-B compounds were found. Consequently, the soft magnetic property of the alloy deteriorated.2. We studied the static magnetic properties of (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ nanocrystalline alloy at room temperature. Results showed that the excellent soft magnetic properties can be obtained for (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ annealed at 490～550℃,especially at 490℃. At the same time, we successfully proved the inversely-proportional relationship between permeability and coercivity as well as permeability and effective magnetic anisotropy constant.3. We studied the high-temperature magnetic properties of (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ nanocrystalline alloy, including temperature dependence of permeability and the influence of the additive Co on high-temperature behaviour in Fe_73.5Cu₁Mo₃Si_13.5B₉ alloy. We found that the initial permeability of (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ alloy annealed at 550℃has little decrease in the course of continuous calefaction below 450℃. The additive Co makes high-temperature property better obviously. Contrasted with Fe_73.5Cu₁Mo₃Si_13.5B₉ alloy, the Curie temperature and magnetization for (Fe_0.5Co_0.5)_73.5Cu₁Mo₃Si_13.5B₉ alloy have great improvement. The above results are significant to look for new type of nanocrystalline materials for high temperature application.4. We made a investigation on high-frequency magnetic properties of...