Ion beam assisted deposited tantalum oxide coatings on aluminum

Ion beam assisted deposition (IBAD) and sputter deposition were used to produce tantalum oxide surfaces on aluminum substrates. The corrosion behavior of the sputter deposited coatings and IBAD modified regions was studied by anodic polarization in deaerated, 0. 1 M NaCl solutions. The electrochemical results showed that the tantalum oxide surfaces significantly improved the pitting corrosion resistance of the substrate metal. The best results were obtained for samples with 1.8 μm thick tantalum oxide IBAD modified surfaces. These samples have an average pitting potential value that is 0.850 V higher than that of pure aluminum. X-ray photo-electron spectroscopy showed that the surface of the IBAD samples was composed of Ta 2O 5 as well as tantalum carbide and tantalum suboxide species.