New Fe-Cr-Mo-(Nb, Ta)-C-B glassy alloys with high glass-forming ability and good corrosion resistance

New Fe-based glassy alloys of Fe45Cr16Mo16C18B5 Fe45Cr16Mo14Nb2C18B5 and Fe 5Cr16Mo14Ta2C18B5 were synthesized. They exhibit a large supercooled liquid region (DeltaT(x)) reaching 58 K before crystallization and high reduced g lass transition temperatures (T-g/T-m) up to 0.62. These values indicate th at these Fe-based alloys have a glass-forming ability which is high enough to enable die formation of bulk glassy alloys. The Fe-based glassy alloys h ave high corrosion resistance in 1, 6 and 12 mol L-1 HCl solutions at room temperature. HCl corrosion rates are in the range of 10(-4)-10(-2) mm.y(-1) . The glassy alloys are spontaneously passivated in 1 and 6 mol.L-1 HCl sol utions with wide passive region and low passive current density in the rang e of 10(-4)-10(-2) A.m(-2). No pitting corrosion is seen even in 12 mol.L-1 HCl solution. The addition of Nb or Ta to the glassy alloys is effective o n enhancing the corrosion resistance.