Oxidation behavior of β-Nb precipitates in Zr-1Nb-0.2Bi alloy corroded in lithiated water at 360 °C

The oxidation behavior of β-Nb precipitates in Zr-1Nb-0.2Bi alloy corroded in lithiated water with 0.01 M LiOH at 360 °C/18.6 MPa was investigated by high-resolution transmission electron microscopy (HRTEM). From the HRTEM observation and the analysis for the oxide layer, the oxidation behavior of β-Nb precipitates corroded in lithiated water in early stage is as follows: β-Nb precipitates are first oxidized to NbO2, then part of it is further oxidized to Nb2O5 in some specific crystallographic orientations. The reason for accelerated corrosion of Zr-Nb alloys in lithiated water is discussed from the rapid oxidation of β-Nb precipitates.