Microstructures and Magnetic Properties of Co-Zr System Alloys

Abstract

The microstructures and magnetic properties of Co_90−xZr_10+x (x=0–20) alloy ingots and those melt-spun ribbons were examined in order to clarify the phase and microstructure of the Co–Zr system alloys. The Co₉₀Zr₁₀ alloy ingot and melt-spun ribbon consisted of Co, Co₂₃Zr₆, and Co₁₁Zr₂ phases. Although the Co₈₀Zr₂₀ alloy ingot consisted of Co, Co₂₃Zr₆, and Co₁₁Zr₂ phases as was the case for the Co₉₀Zr₁₀ alloy ingot, those melt-spun ribbon consisted of metastable Co₅Zr phase together with Co and Co₂₃Zr₆ phases. The Co₇₀Zr₃₀ alloy ingot and melt-spun ribbon consisted of Co₂Zr phase. Among the alloy ingots and those melt-spun ribbons, only the Co₈₀Zr₂₀ melt-spun ribbon with the metastable Co₅Zr phase exhibited a high coercivity. This study confirmed that the hard magnetic phase was not the Co₁₁Zr₂ phase but the metastable Co₅Zr phase.