ION-BEAM-ASSISTED DEPOSITED TANTALUM OXIDE COATINGS ON ALUMINUM

Ion beam assisted deposition (IBAD) and sputter deposition were used t o produce tantalum oxide surfaces on aluminum substrate. The corrosion behavior of the sputter deposited coatings and IBAD modified regions was studied by anodic polarization in deaerated, 0.1M NaCl solutions. The electrochemical results showed that the tantalum oxide surfaces si gnificantly improved the pitting corrosion resistance of the substrate metal. The best results were obtained for samples with 1.8 mu m thick tantalum oxide IBAD modified surfaces. These samples have an average pitting potential value that is 0.850 V higher than that of pure alumi num. X-ray photo-electron spectroscopy showed that the surface of the IBAD samples was composed of Ta2O5 as well as tantalum carbide and tan talum suboxide species. Published by Elsevier Science Ltd.