The origin of the coercivity in Co-Zr system alloys

The phases and magnetic properties of Co-Zr melt-spun ribbons were studied to investigate the origin of the hard magnetic phase in Co-Zr system alloys. The Co-Zr melt-spun ribbons with coercivities of 1.5-2.7 kOe consisted of a metastable Co/sub 5/Zr phase together with fcc-Co and Co/sub 23/Zr/sub 6/ phases. Annealing at relatively high temperatures (700-800(degree)C resulted in the formation of an equilibrium Co/sub 11/Zr/sub 2/ phase). However, the annealed ribbons with the Co/sub 11/Zr/sub 2/ phase showed a lower coercivity than those without the Co/sub 11/Zr/sub 2/ phase. The hard magnetic phase of the Co-Zr system alloys was believed to be the metastable Co/sub 5/Zr phase.