Corrosion behavior of carbon-implanted zircaloy-4 in 1 M H2SO4

In order to study the effect of carbon ion implantation on the aqueous corrosion behavior, samples of zircaloy-4 were implanted with carbon ions with fluences ranging from 1 × 1016 to 1 × 1017 ions/cm2, using a metal vapor vacuum arc source (MEVVA) operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES), respectively. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the carbon ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircaloy-4 in a 1 M H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion behavior of zircaloy-4 implanted with carbon ions when the fluence is smaller than 5 × 1016 ions/cm2. The higher the fluence, the worse is the corrosion resistance. Finally, the mechanism of the corrosion behavior of carbon-implanted zircaloy-4 was discussed.