Investigation of Structure and Magnetic Properties of Melt-Spun Co-Zr-(B, Al) Ribbons

In this work, we investigated structure and magnetic properties of melt-spun Co-Zr-(B, Al) ribbons. The appropriate adjustment of concentration of Zr in Co100−xZrx (x = 16, 18, and 20) alloys is necessary to create the rhombohedral Co11Zr2 hard magnetic phase. The addition of B element increases the glass forming ability (GFA) of Co80Zr20−xBx (x = 0, 2, 3, and 4) alloys. The highest saturation magnetization Ms and coercivity Hc of 72.6 emu/g and 2.9 kOe are respectively obtained with B concentration of 2%. The more addition of Al and annealing process at 550 °C for 1 h facilitate Co77Zr20−xAlxB3 (x = 0, 2, 3, and 4) alloys to prevent the formation of undesired soft magnetic phases of the orthorhombic Co11Zr2, cubic Co23Zr6, and face centered cubic Co. The Ms increases from 51.5 to 62.3 emu/g with increasing Al concentration from 0 to 4%, but the Hc decreases from 4.3 to 2.8 kOe for these alloys. The obtained magnetic parameters show an application potential of the Co-Zr-based rare earth-free hard magnetic materials in practice.