Transformation of amorphous passive oxide film on Zr₆₅Cu_17.5Ni₁₀Al_7.5 metallic glass ribbons

Zr-based metallic glass with favorable properties and a stable surface oxide layer is foreseen as an alternative material for water/nuclear reactor pressure systems. The high stability of Zr65Cu17.5Ni10Al7.5 metallic glass (MG) in anodic and cathodic regions within 0.5 M H2SO4 solution is evidenced by the negligible shift in the corrosion potential upon linear sweep voltammetry cycles. The recorded passivation current density of 15 mA cm–2 is very similar to 430 stainless steel. The formation of an amorphous Zr-rich oxide phase and slight dissolution of the native ZrO2 layer are confirmed by scanning transmission electron microscopy – energy dispersive X-ray analysis, which result from the interaction of hydronium ions (H3O+) with the oxide layer during linear polarization. Furthermore, promising hydrogen absorption of the produced Zr-based MG ribbons (1.33 %wt, non-reversible) by Sieverts-type apparatus were recorded at 400 °C and under 6 MPa, which evidences that this alloy can minimize the hydrogen evolution within the chamber due to the coverage with an oxide film and thereby prevent accidents.