Crystallization behavior of (Fe100−xCox)62Nb8B30 bulk amorphous alloy

The effect of Co addition on the glass-forming ability (GFA) has been investigated in the (Fe100−xCox)62 Nb8B30 (x=0, 33, and 50) bulk amorphous alloy system by differential scanning calorimeter (DSC). The thermal stability measured by the apparent activation energies decreased from about 5.5 to 4.5 eV upon Co addition. The glass-forming ability measured by the temperature interval Tx−Tg was decreased substantially compared to Fe62Nb8B30 alloy, but it is still large enough for practical applications. The DSC and DTA parameters, Tg, Tx, Tm and Tl were combined in different parameters, Tg/Tm, Tx/Tl and Tx/(Tg+Tl) and Tx/(Tl−Tg) to express the glass-forming ability. The cystallization products were studied by XRD. The metastable Fe23B6 crystallization product was found in all the alloys.