Anodic Fabrication of Ti-Ni-Si-O Nanostructures on Ti10Ni5Si Alloy

Ti-Ni-Si-O nanostructures were synthesized on Ti10Ni5Si alloy through an electrochemical anodization in electrolyte solutions containing ammonium fluoride (NH4F). The anodic oxide structures were affected by the electrochemical anodization parameters, including the electrolyte viscosity, water content, anodization potential and anodization time. Using an anodization potential of 40 V for 90 min in an ethylene glycol/glycerol electrolyte with 3 vol.% deionized water, highly ordered self-organized nanotube arrays were obtained in the α-Ti phase region of the alloy substrate, with an average inner diameter of 70 nm and a wall thickness of about 12 nm. Self-organized nanopore structures with an average pore diameter of 25 nm grew in the Ti5Si3 phase region. Only etching pits were found in the Ti2Ni phase region. The Ti-Ni-Si-O nanostructures were characterized using scanning electron microscopy and energy dispersive spectroscopy. In addition, a formation mechanism of different nanostructures was presented.