As a valuable process for surface modification of materials, ion implantation is eminent to improve mechanical properties, electrochemical corrosion resistance and oxidation behavior of varieties of materials. To investigate and compare the electrochemical behavior of zirconium and zircaloy-4, implantation of yttrium and cerium ions were, respectively, employed by using a MEVVA source at 40 kV with a fluence range from I x 10(16) to 1 X 10(17) ions/cm(2). The valence of the surface layer was analyzed by X-ray photoelectron spectroscopy (XPS). Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium and zircaloy-4 in a IN H2SO4 solution. It was obviously found that the corrosion resistance of samples implanted with yttrium increase with raising fluence, while the corrosion resistance of samples implanted with cerium decline with raising fluence. Finally, the mechanism of the corrosion behaviors of the Y and Cc implanted zirconium and zircaloy-4 was discussed. (C) 2003 Elsevier B.V. All rights reserved.