EFFECT OF SILICON ADDITION ON THE MAGNETIC-PROPERTIES OF FE-B-C AMORPHOUS-ALLOYS

The effect of compositions on the saturation magnetization, Curie temperature and coercivity of the amorphous Fe-B-C alloys has been investigated in a wide range of B and C concentration. The C addition less than 7 at.% to Fe-B alloys increases the saturation magnetization at the room temperature. The highest magnetization, σs = 178 emu/g, with the lowest coercive force, Hc = 22 mOe, has been obtained for the Fe81B 12-C7 alloy annealed in a magnetic field. In order to obtain further desirable soft magnetic properties, the effect of the addition of other elements to the Fe-B-C based amorphous alloys has been studied. The best properties are σs (R.T.) = 176 emu/g, Hc = 8 mOe, Br/B100 = 0.88 and the core loss W/f = 8×10 -4 watt. sec/kg (at 12.5 kG and 50 Hz) for the magnetically annealed Fe81B13C2Si4 alloy. As a result, it has been found that the addition of Si is most effective in reducing the coercive force and core loss as well as an improving the magnetic stability during aging at low temperatures.