Anodization of Ti-Ni Alloy Pellets Formed by Powder Metallurgy

In this study, titanium-nickel (Ti-Ni) alloy pellets with varying compositions (Ti-10Ni, Ti-25Ni, and Ti-50Ni) were fabricated using powder metallurgy. Titanium powders were mixed with different Ni contents, ball-milled, compacted, and sintered to form dense pellets with Ti2Ni and TiNi phases in Ti-25Ni and Ti-50Ni, and approximately 50% α-Ti and 50% Ti2Ni in Ti-10Ni. Following polishing, the pellets were anodized at 60 V in fluoride electrolyte to form anodic films preferable with nanotubular structure. The anodic oxide on Ti-10Ni exhibited a nanotubular structure, with nanotube diameters ranging from 80-100 nm, similar to those observed on pure Ti pellets. X-ray diffraction indicated that the nanotubes on Ti-10Ni were predominantly anatase TiO2 with nickel dopants. Anodized Ti and Ti-10Ni pellets were then tested for their photocatalytic properties in reducing Cr(VI) under UV and sunlight illumination. Ti-10Ni demonstrated complete Cr(VI) reduction to Cr(III) and achieved faster photoreduction compared to anodized pure Ti. This technique offers a straightforward method for Cr(VI) removal from contaminated wastewater, highlighting its potential for industrial applications in water treatment to eliminate heavy metal ions effectively.