Microstructures and Magnetic Properties of Co-Zr System Alloys

Abstract

The microstructures and magnetic properties of Co90-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 Co11Zr 2 phases. Although the Co80Zr20 alloy ingot consisted of Co, Co23Zr6, and Co11Zr 2 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 Co 70Zr30 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.