2003 Volume 44 Issue 9 Pages 1713-1716
The microstructures and magnetic properties of Co90−xZr10+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.