Corrosion Characteristics of Zr-based Alloys with Cu Addition

摘要

The effect of Cu addition to the Zr-based alloy that developed for nuclear fuel cladding was investigated. The alloys were finally heat-treated at 470, 520, 580 deg C for 2.5 hours. The microstructures were examined by using optical microscope. Transmission electron microscopy (TEM) equipped with energy dispersive X-ray spectroscopy (EDS) also has been used to study the composition and structure of intermetallic precipitates. The corrosion tests of the alloys having different Cu content were tested in both 360 deg C water and 400 deg C steam environment. In addition, the oxide film characteristics were analyzed by using low-angle X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS). With the increase of Cu content, the Cu concentration in precipitates was increased. The corrosion test showed that the weight gain increased consistently with the increase of Cu content. In the effect of final annealing, the corrosion resistance decreased gradually with the increase of annealing temperature. As a result of oxide film analysis, the oxide films of the sample having good corrosion resistance had a high fraction of tetragonal ZrO_2 and dense oxide layer.