Magnetization Process in Co-Zr-B permanent-magnet materials

Co-Zr-B alloy ingots consisted of Co/sub 23/Zr/sub 6/ phase together with the small amounts of Co/sub 5/Zr and Co/sub 3/ZrB/sub 2/ phases. On the other hand, Co-Zr-B melt-spun ribbons consisted mostly of Co/sub 5/Zr phase and exhibited a high coercivity. Heat treatment of the Co-Zr-B melt-spun ribbons resulted in increased coercivity. These annealed Co-Zr-B melt-spun ribbons were magnetically isotropic. The maximum energy products (BH)/sub max/ values in excess of 4.7 MGOe were observed for the Co-Zr-B melt-spun ribbons annealed at 600/spl deg/C for 1 h. The mechanism underlying the coercivity of the annealed Co-Zr-B melt-spun ribbon was found to be the pinning type from the initial magnetization curve.