Effect of Ni Ion Implantation on Corrosion Behavior of Zircaloy-4 in 0.5 M H 2 SO 4

In order to study the effect of nickel ion implantation on aqueous corrosion behavior, samples of Zircaloy-4 were implanted with nickel ions with fluences ranging from 1 × 10 16 to 5 × 10 17 ions / cm 2 using a metal vapor vacuum arc source operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface of the samples were analyzed by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. Transmission electron microscopy was used to examine the microstructure of the nickel-implanted samples. The potentiodynamic polarization measurement was employed to evaluate the aqueous corrosion resistance of Zircaloy-4 in a 0.5 M H 2 SO 4 solution. It was found that significant improvement was achieved in the aqueous corrosion resistance when the fluence is 1 × 10 16 Ni / cm 2 . For fluences greater than 1 × 10 16 Ni / cm 2 , the corrosion resistance of the implanted zirconium decreased compared with that of as-received Zircaloy-4; the higher the fluence, the worse the corrosion resistance. The mechanism of the corrosion behavior of the nickel-implanted Zircaloy-4 is discussed. © 2004 The Electrochemical Society. All rights reserved.