Surface analysis of zirconium samples implanted with molybdenum

Zirconium specimens were implanted with molybdenum ions with a fluence ranging from 1x1016 to 5x1017 ions/cm2 at approx. 160 deg. C using a MEVVA source at an extraction voltage of 40 kV. The surfaces of the implanted samples were then analyzed and the Trim 96 computer code was used to simulate the depth distribution of molybdenum. Depth distributions of elements in the surface of samples before oxidation obtained by Auger electron spectroscopy (AES) showed that the oxide film on the zirconium substrate became thicker with increasing implantation fluence. The valence states of elements in the implanted surface layer before and after oxidation at 600 deg. C in air for 100 min were analyzed by X-ray photoelectron spectroscopy (XPS). The molybdenum, which was partially metallic in the implanted surface, was completely converted into MoO3 as a result of the heating. Glancing angle X-ray diffraction (GAXRD) at a 0.3 deg. incident angle was used to examine the phase structures of implanted samples before oxidation. Tetragonal zirconia was found for a fluence of 1x1016 ions/cm2. At larger fluences both tetragonal and monoclinic zirconia were found