Abstract :
Ba-Zn system W-type hexagonal ferrite magnets were prepared by a new manufacturing method in which BaO was added after semisintering treatment, and without atmosphere control. This process was found to be very useful in stabilizing the W-type hexagonal structure. The optimum conditions for making magnets, and some properties of typical specimens, are as follows: chemical analysis Ba1.092Zn1.725-Fe2+ 0.410Fe3+15.848O27; semisintering conditions 1275°C×1.0 hr in air; sintering conditions 1225°C×0.5 hr in air; magnetic and physical properties Jm=0.405 T, Jr=0.364 T, HcJ=86.0 kA/m, HcB=82.0 kA/m, (BH)max=18.5 kJ/m3, TC=330°C, HA=987.0 kA/m, KA=1.87×105J/m3, and nB=33.7¿B.
