Fabrication and characterization of the microporous and nanoporous anodic oxidations of titanium–silver alloys

Abstract

The purpose of this study was to fabricate and evaluate the morphological structure of microporous anodic oxidation (MAO) or nanoporous anodic oxidation (NAO) treated titanium-silver (Ti-Ag) alloys. The Ti-Ag alloys were arc melted, homogenized, and quenched in water at room temperature. The MAO treatment was performed using β-glycerol phosphate (β-GP) and calcium acetate (CA) solution; the NAO treatment was performed using hydrofluoric acid (HF) solution or ammonium fluoride (NH4F) solution. Surface-treated Ti-Ag alloys were compared to commercially pure titanium (cp Ti). The surface morphology and phase state were analyzed by field emission scanning electron microscopy (FE-SEM) and high resolution X-ray diffraction (HR-XRD). Both the MAO treated cp Ti and Ti-Ag alloy samples presented a regular oxide layer with a diameter of approximately 1–3 µm. Morphology was clearly visible on NAO Ti-Ag alloy samples treated with NH4F solution, with a diameter of roughly 100 nm. However, HF solution treated NAO Ti-Ag alloy samples appeared to be sparsely- and irregularly-shaped, ranging in size from a few nanometers to 100 nm. From the HR-XRD analysis, amorphous TiO2, Ti, and Ti-Ag phases were observed in the MAO and NAO treated Ti-Ag alloys. The MAO and NAO treated cp Ti samples only showed peaks associated with Ti. The surface characteristics of Ti-Ag alloys may possibly influence cell viability