Electrical corrosion effects of pure iron implanted with Ti and Pd ion beams

The electrochemical corrosion behaviour of Ti and Pd ion implanted pure iron specimens in 0.5 mol l−1 sodium acetate/acetic acid (NaAc/HA) aqueous or buffer solution with pH 5.0, respectively, has been studied. The ion implantations were performed by using a MEWA source ion implantor. The changes in composition and valency states of elements in the near surface layers of implanted specimens compared with the control were analyzed by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The changes in electrochemical corrosion behaviour of implanted iron demonstrated that: (1) Ti ion implantation induced nobler corrosion potential, depressed corrosion current and enhanced polarization resistance; (2) Pd ion, implantation decreased the critical passitive current of iron and maintained a better passivity in acetate buffer solution with pH 5.0 and (3) the active corrosion rate of Pd implanted iron was even higher than that of unimplanted specimens when oxide films had been damaged.