Ideal Hexagonal Order: Formation of Self-Organized Anodic Oxide Nanotubes and Nanopores on a Ti–35Ta Alloy

In this work, we report on the formation of highly aligned nanoporous or nanotubular oxide structures by anodization of Ti–Ta alloys in containing ethylene glycol electrolytes. We show that depending on the anodization conditions, either a hexagonally self-organized nanoporous layer or a nanotube array can be formed. Critical factors that decide on tube or pore formation are the water content of the electrolyte and the applied voltage. The present approach provides hexagonally packed oxide structures with an order comparable to that of the gold standard, anodized alumina. Layers of thicknesses and individual pore diameter in the range of 27–50 nm can easily be produced.