Partial crystallization and corrosion resistance of amorphous Fe-Cr-M-B (M = Mo, Nb) alloys

The present paper evaluates the corrosion resistance of four new amorphous Fe-Cr-based alloys containing Mo or Nb, as well as their thermal stability and the effect of their partial crystallization. Ribbons of Fe68B20Cr12, Fe67.7B20Cr12Mo0,3, Fe67.7B20Cr12Nb0,3 and Fe67.7B20Cr12Nb0,15Mo0,15 alloys were processed by the melt-spinning technique. The crystallization process of the four compositions occurs in a single-stage step with the simultaneous precipitation of fcc-Fe and Fe3.5B phases. The addition of Nb and/or Mo leads to an increase in the crystallization temperature, indicating that these elements stabilize the amorphous phase. The results also indicate that the alloy containing both Nb and Mo presented greater uniform corrosion resistance than the alloy containing either one or the other of these elements in NaCl and H2SO4 solution.