The pitting corrosion behavior of aluminum ion implanted with tantalum

The corrosion behavior of Ta-Al surface alloys produced by ion implantation at room and liquid nitrogen temperatures was examined in de-aerated, 0.1M NaCl. Surface analysis using Rutherford backscattering spectroscopy and X-ray photoelectron spectroscopy showed that the surface concentration of Ta was greater in samples that were ion implanted at liquid nitrogen temperatures. Anodic polarization curves showed that Ta ion implanted into Al at room temperature and a liquid nitrogen temperature increased the pitting potential of Al by 50 mV and 175 mV, respectively. From the standpoint of the pH of zero charge model, this behavior is explained by the presence of the implanted cations in the aluminum-oxide lattice. (orig.)