FeCo-based FeCoBPSiCr Amorphous Alloy and Powder with High Saturation Magnetic Flux Density and Corrosion Resistance

抄録

  Soft magnetic materials are required to obtain high saturation magnetic flux density (B_s) and corrosion resistance for suppressing the magnetic saturation and supporting usage environments in power supplies of information and communication technology (ICT) devices with large current driving. This study investigated the magnetic characteristics, amorphous stability, and corrosion behavior of (Fe_0.7Co_0.3)_88−x−yB₁₁P_xSi_yCr₁ and conventional Fe₇₉Si₆B₁₃C₂ amorphous alloys. A metallic ribbon comprising (Fe_0.7Co_0.3)₈₂B₁₁P₄Si₂Cr₁ exhibited high B_s of 1.71 T and amorphous forming ability of 87 μm, sufficient to obtain a single amorphous phase even in powder morphology. The (Fe_0.7Co_0.3)₈₂B₁₁P₄Si₂Cr₁ amorphous alloy ribbon with a high corrosion potential of −520 mV showed better corrosion resistance than conventional Fe₇₉Si₆B₁₃C₂ amorphous alloy with a low corrosion potential of −677 mV in water immersion tests. The (Fe_0.7Co_0.3)₈₂B₁₁P₄Si₂Cr₁ amorphous alloy powder comprised a single amorphous phase and exhibited high B_s of 1.61 T, the same as that of the conventional Fe₇₉Si₆B₁₃C₂ amorphous alloy powder. Furthermore, an inductor using the (Fe_0.7Co_0.3)₈₂B₁₁P₄Si₂Cr₁ amorphous alloy powder exhibited high DC-bias characteristics and excellent corrosion resistance compared to that using the conventional Fe₇₉Si₆B₁₃C₂ amorphous alloy powder. The results suggested that inductor using the (Fe_0.7Co_0.3)₈₂B₁₁P₄Si₂Cr₁ amorphous alloy powder with high DC-bias characteristic and excellent corrosion resistance contribute to correspond to large current and high reliability of ICT devices.