The oxidation behaviour of molybdenum ion-implanted zircalloy-4 in air at 600°C

Abstract

The oxidation behaviour of molybdenum ion implanted zircalloy-4 in air at 600°C has been studied. Zircalloy-4 specimens were implanted with molybdenum ions using the MEVVA source at 40 kV with a fluence from 1×10 16 to 5×10 17 ions/cm 2 at a maximum temperature of 160°C. Weight gain curves were measured after oxidation in air at 600°C for 6000 s. They showed a significant decline in the oxidation resistance of zircalloy-4 implanted with molybdenum as compared with that of the as-received zircalloy-4. Depth distributions of the elements in the surface of the samples before oxidation were obtained by auger electron spectroscopy. The valence states of the implanted elements in the implanted surface layer were analyzed before and after oxidation by X-ray photoelectron spectroscopy; glancing angle X-ray diffraction at 0.3° incident angle was employed to examine the phase structures of the implanted samples after oxidation in air at 600°C for 6000 s, and it was clearly found that there were no differences between the implanted samples and unimplanted sample. The mechanism of oxidation behaviour due to molybdenum ion implantation is discussed.