Bulk glassy Fe-Co-Ga-P-C-B alloys with high glass-forming ability, high saturation magnetization and good soft magnetic properties

The effect of ferromagnetic metal Co on the glass-forming ability and magne tic properties for the Fe75-xCoxGa5P12C4B4 glassy alloys was investigated. The additions of 10 to 15 at%Co were found to be effective for the extensio n of the supercooled liquid region (DeltaT(x)) defined by the difference be tween the glass transition temperature (T-g) and crystallization temperatur e (T-x). The DeltaT(x) value is 37 K for the Fe75Ga5P12C4B4 alloy and incre ases to 48 K for the 10, 12.5 and 15 at%Co alloys. The liquidus temperature (T-l) of the 10, 12.5 and 15 at%Co alloys decreased by the addition of Co and the reduced glass transition temperature (T-g/T-l) increased. The large st T-g/T-l is 0.61 for the Fe65Co10Ga5P12C4B4 alloy. These glassy ribbon al loys exhibit good soft magnetic properties of 1.15 to 1.33T for saturation magnetization and 2.4 to 3.6 A/m for coercive force. Based on the large Del taT(x) and high T-g/T-l values, we tried to prepare bulk glassy Fe75-xCocGa 5P12C4B4 (x = 10, 12.5, 15) rods in a cylindrical form with different diame ters. The glassy single phase was obtained in the diameter of 1.5 mm in the composition range of 10 to 15 at%Co.