On the oxidation behavior of (Zr,Nb)2Fe under simulated nuclear reactor conditions

The corrosion behavior of Zr alloys was affected by second phases, especially by those containing Fe and Nb. Ti2Ni-type (Zr,Nb)2Fe compound was melted and exposed to H2O2 water solution at 320 °C and 16.4 MPa for 60 h. The oxide layer was analyzed by X-ray diffraction and high-resolution transmission electron microscope (HRTEM). The formation of nano-crystalline tetragonal ZrO2 (Fe-rich area) and amorphous ZrO2 (Fe-deficient area) was observed. HRTEM analysis identified α-Fe could stabilize tetragonal ZrO2 due to the epitaxial growth. ZrxFeyNb alloys with different iron were melted and corroded similarly. The result was consistent with the proposed mechanism.