Microstructural analysis and corrosion behaviour of D9 stainless steel – Zirconium metal waste form alloys

Metal waste form (MWF) alloys of D9 stainless steel with 5–20 wt.% zirconium (Zr) were cast and used for the present work. The microstructural analysis by scanning electron microscopy of as-cast MWF alloys showed the presence of two distinctly different phases. Phases identified by X-ray diffraction techniques are mostly iron-based γ-austenite, Fe–Zr and Ni–Zr-type intermetallics. Corrosion properties evaluated by potentiodynamic polarization method in de-mineralized water at pH 1, 5, and 8 showed lower breakdown potential at pH 1 compared to pH 5 and 8. Impedance study showed a single semicircle curve with high polarization resistance indicating stable passive film under all conditions.