Nanotube Morphology Changes on the Ti-xNb-Ag-Pt Alloy with Nb Contents

The purpose of this study was to investigate the nanotube morphology changes of Ti-xNb-Ag-Pt alloys with Nb content. Ti-xNb-Ag-Pt was fabricated using arc melting vacuum furnace. The Ti- xNb-Ag-Pt ingot was further homogenized in an Ar atmosphere at 1100 °C for 1 h in a vacuum and then quenched at 0 °C. Nanotube formation on the samples was performed using anodization method with a DC power supply at 30 V for 2 h in 1 M H₃PO₄ +0.8 wt.% NaF at 25 °C. The surface morphology was observed using OM, FE-SEM, EDS, and XRD. In the microstructure of Ti-xNb-Ag-Pt alloy, needle-like structures on α and α″ gradually disappeared with increasing Nb, β-phase equilibrium structure appeared, and particle size decreased. The nanotube morphology of the Ti-xNb-Ag-Pt alloy changed according to the content of Nb. As the Nb content increases, the highly ordered nanotubes have changed to irregular nanotubes. The difference in dissolution area at the bottom of the nanotube was depending on the Nb content.