Influence of molybdenum ion implantation on the aqueous corrosion behavior of zircaloy-4

In order to study the effect of molybdenum ion implantation on the aqueous corrosion behavior of zircaloy-4, specimens were implanted by molybdenum ions with a fluence range from 1×1016 to 1×1017 ions/cm2 at maximum 160 °C, using MEVVA source at an extracted voltage of 40 kV. The valence and elements penetration distribution of the surface layer were analyzed by X-ray photoemission spectroscopy and auger electron spectroscopy, respectively. Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zircaloy-4 in a 1 N H2SO4 solution. Scanning electron microscopy was performed for the three-sweep potentiodynamic polarized samples. It was found that a significant improvement was achieved in the aqueous corrosion behavior of zircaloy-4 implanted with molybdenum fluence when the fluence is smaller than 5×1016 ion/cm2. When the fluence is higher than 1×1017 ion/cm2, the corrosion resistance of zircaloy-4 implanted with molybdenum ions decreased compared with that of the as-received zircaloy-4. Finally, the mechanism of the corrosion behavior of the molybdenum-implanted zircaloy-4 is discussed.