Effect of cerium ion implantation on the oxidation behavior of zircaloy-4 at 500 °C

In order to investigate the oxidation behavior changes of zircaloy-4 induced by cerium ion implantation using a MEVVA source at an energy of 40 keV with a dose range from 1 x 10(16) to 1 x 10(17) ions/cm(2) at the maximum temperature of 130 degreesC, weight gain curves of the different specimens including as-received zircaloy-4 and cerium-implanted zircaloy-4 were measured after oxidation in air at 500 degreesC for 100 min. It was obviously found that a significant improvement was achieved in the oxidation behavior of cerium ion implanted zircaloy-4 compared with that of the as received zircaloy-4. The depth profile of the element composition in the surface region of the samples was obtained by Auger electron spectroscopy, and the valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy. Glancing angle X-ray diffraction employed to examine the phase transformation in the oxide films showed that the addition of cerium transformed the phase from monoclinic zirconia to hexagonal zirconia. Finally, the mechanism of the improvement of the oxidation behavior is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.