Influence of Cr micro-addition on the glass forming ability and corrosion resistance of Cu-based bulk metallic glasses

(Cu₄₇Zr₁₁Ti₃₄ Ni₈)_100-xCr_x(x = 0, 0.5 and 1.0) bulk metallic glasses (BMGs) were obtained by water-cooled copper mold casting. The effect of Cr micro-addition on the glass-forming ability (GFA) of the alloys was investigated by means of XRD, DSC and DTA. It was found that Cr micro-addition can enhance the GFA. Electrochemical measurements were carried out in 1 mol/L HCl, 3% NaCl and 6 mol/L KOH aqueous solutions by potentiadynamic polarization method at room temperature. It is shown that all the BMGs exhibited spontaneous passivation in the above electrolytes, and with the increase of Cr content, the passive zone remarkably increased and the passive current density decreased, implying better corrosion resistance of Cu-based BMGs with higher Cr content. The present results also demonstrated that the corrosion resistance of Cu-based BMGs with Cr microaddition is much better than that of the stainless steel.