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 x 10(16) to 1 x 10(17) ions/cm(2) at maximum 160 degreesC, 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 x 10(16) ion/cm(2). When the fluence is higher than 1 x 10(17) ion/cm(2), 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. (C) 2003 Elsevier Science B.V. All rights reserved.