Thermal oxidation effect on corrosion behavior of Zr46Cu37.6Ag8.4Al8 bulk metallic glass

Oxide films of 0.72 μm and 1.80 μm were prepared by thermal oxidation treatments at 441 K and 609 K respectively. The oxidation kinetics of the Zr46Cu37.6Ag8.4Al8 bulk metallic glass has been investigated. The outermost surface of the oxide film formed at 609 k is Cu2O and Al2O3-enriched but ZrO2-depleted. A ZrO2-enriched oxide layer is detected existing at 150–260 nm of the oxide film. The surface oxidation state sheds great influence on the corrosion behavior of Zr-based BMG. The oxide film can hinder the initial electrodissolution processes during polarization in 0.5 M H2SO4 + 0.01 M NaCl solution. The special structure and composition distribution of the oxide film lead to the modification of the BMG’s corrosion behavior.

Thermal oxidation treatments shed great influence on corrosion behavior of the Zr-based BMG. The samples oxidized at 609 K much higher corrosion current density in both 0.5 M H2SO4 and 0.5 M NaCl solutions. However, in the 0.5 M H2SO4 + 0.01 M NaCl solutions, the oxidized samples exhibit lower electrodissolution peaks than the as-prepared sample, which is thought mainly improved by the formation of a ZrO2-enriched oxide layer at the depth of 150–260 nm.Figure optionsDownload as PowerPoint slideHighlights
► Oxide film with a two-layer structure can be formed by oxidation.
► The outermost of the oxide film formed at 609 K is enriched in Cu and Al but depleted in Zr.
► A ZrO2-enriched oxide layer was detected existing at the depth of 150–260 nm of the oxide film.
► Oxide film property sheds great influences on the corrosion behavior of Zr-based BMG.
► The active-dissolution processes during polarization in 0.5 M H2SO4 + 0.01 M NaCl were hindered by the oxide film.