Effect of oxygen plasma immersion ion implantation on the formation of nanostructures over Ni–Ti alloy

Abstract

Ni–Ti alloy has been implanted with oxygen ions by plasma immersion ion implantation (PIII-O). Ni–Ti–O nanotubes are formed by anodic oxidation of PIII-O Ni–Ti alloy. The surface of the modified alloy samples has been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion behaviors of the Ni–Ti substrate, PIII-O and anodized PIII-O samples have been investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks' solution). It has been observed that oxygen ion implantation leads to the formation of a thin oxide layer on the Ni–Ti alloy. Anodization of the implanted alloy results in Ni–Ti–O nanotubes. Corrosion resistance of the PIII-O and anodized PIII-O samples shows better corrosion resistance compared to that of untreated alloy.