Corrosion and Oxidation Behavior of Zr58Cu22Fe4Co4Al12 Metallic Glass

The pitting corrosion behavior of melt spun ribbon made at a wheel speed of 20 ms in 3.5 wt% NaCl solution and nonisothermal and isothermal oxidation behavior of 2 mm diameter rod samples of newly developed Zr₅₈Cu₂₂Fe₄Co₄Al₁₂ bulk metallic glass have been studied. The pitting corrosion is more on the air side as compared to the wheel side mainly due to the presence of air pockets. The pitted regions are enriched with copper suggesting dealloying effect due to its noble nature. The alloy shows very good oxidation resistance compared to some of the exiting bulk metallic glass forming alloys. The oxidation leads to the formation of mainly tetragonal ZrO₂ with the presence of monoclinic ZrO₂, mixture of CuO and Cu₂O and Al₂O₃. Copper in the alloy oxidized progressively with the appearance of white flowery globule shape which later forms interconnected faceted CuO network.