Magnetic properties, phase evolution, and microstructure of the Co-Zr-V ribbons

The substitution of V for Zr significantly impeded the growth of grain in the Co82Zr18 ribbons during melt spinning and the amorphous Co82Zr13V5 melt-spun ribbons were successfully produced at a wheel speed of 40 m/s. The values of coercivity Hc and maximum energy product (BH)max first increased, reaching maximum at 560 °C and then they decreased sharply with increasing the annealing temperature. The optimal magnetic properties of Hc=4.0 kOe and (BH)max=5.0 MGOe were obtained in the amorphous ribbons annealed at 560 °C. A suitable grain size of Co11Zr2 phase was considered to be the main reason for the increase in coercivity.