INFLUENCE OF Co ON THE GLASS FORMING ABILITY AND SOFT MAGNETIC PROPERTY OF Fe–B–Y–Nb BULK AMORPHOUS ALLOY

(Fe1-xCox)71.2B24Y4.8]96Nb4 (x=0, 0.1, 0.2, 0.3 and 0.4) alloy rods with 2—5 mm in diameter were prepared using commercial materials and suction casting method. XRD results show that the substitution of an appropriate amount of Co for Fe can improve effectively the glass forming ability and extend considerably the composition scope for glassy formation. DTA curves indicate that all the alloys with different Co contents exhibit a high glass transition temperature (Tg≥850 K) and wide supercooled liquid region (ΔTx≥97 K). It is also observed that Co substitution for Fe enhances significantly the soft magnetic properties. For the (Fe0.9Co0.1)71.2B24Y4.8]96Nb4 bulk metallic glass, the saturation magnetization (Ms) has a maximum value of 26.6 kA/m, while the coercivity (Hc) is only 59 A/m. In addition, the Curie temperatures of the tested alloys increase continuously with the increase of Co content, and reaches the highest value of 577 K when x=0.4, which is about 100 K higher than that of the base alloy without Co.