Research Article The Electrochemical Stability in NaCl Solution of Nanotubes and Nanochannels Elaborated on a New Ti-20Zr-5Ta-2Ag Alloy Claudiu Constantin Manole, 1 Cristian Pirvu, 1 Andrei Bogdan Stoian, 1 Jose M. Calderon Moreno, 2 Doina Stanciu, 3 and Ioana Demetrescu 1 1 General Chemistry Department, University Politehnica of Bucharest, Polizu 1-7, 011061 Bucharest, Romania 2 Romanian Academy, Institute of Physical Chemistry “Ilie Murgulescu”, Splaiul Independentei 202, 060021 Bucharest, Romania 3 SC R&D Consulting and Services SRL, Strada M. Ghiculeasa 45, 023761 Bucharest, Romania Correspondence should be addressed to Ioana Demetrescu; ioana demetrescu@yahoo.com Received 9 December 2014; Revised 29 January 2015; Accepted 29 January 2015 Academic Editor: Zhenhui Kang Copyright © 2015 Claudiu Constantin Manole et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Nanotubular and nanochannels structures were fabricated via anodizing on a new alloy Ti-20Zr-8Ta-2Ag. A continuous coating of connected tubes/channels can be observed in the SEM micrographs forming tubular structures with diameters in hundreds of nm, as well as smaller tubes, with diameters in tens of nm. In the case of nanochannels structure, the diameters are smaller and wall thicknesses signiicantly thinner than in nanotubes. Wettability measurements indicate a decrease of contact angles in both cases of nanotubes and nanochannels, but the increase of hydrophilic character is more signiicant in the case of nanochannels. he Tafel procedure and electrochemical impedance spectroscopy tests performed in NaCl 0.9% solution indicate a better stability for the nanostructured surfaces compared to untreated alloy, the surface with nanochannels ofering higher corrosion resistance. Spectral UV-VIS determination has conirmed Ag metallic presence, opening the door for applications not only in tissue engineering but for water splitting and the photoreduction of CO 2 as well. 1. Introduction Tailoring materials into nanostructure ofers a large number of opportunities in the exploitation by enhancements of their properties. In this approach, surface modiication of Ti alloys has potential for wide range of applications in tissue engineering, energy, and environment. New Ti bioalloys with nontoxic elements are required for the last generation of advanced orthopedic implants, which need to satisfy more restrictive requirements regarding corrosion and stability in order to extend their service life and to reach more performance. he Al and V substitution in commercial Ti bioalloys with more safety elements and better mechanical properties reducing elasticity modulus and implying values close to human bone (30 GPa) [1, 2] involves important eforts. In this context the new alloys with Nb, Ta, and Zr [3, 4] are considered safe and nonallergenic due to their corro- sion resistance and compatibility with tissue, having also high mechanical resistance. Nowadays, Ta is the most corrosion resistant and most biocompatible metal in use. Ta is not afected by chemical attack at temperatures under 150 ∘ C (ASTM B 521-12) due to its oxides surface; Ta is very ductile but has a high melting temperature (3017 ∘ C) and a very high density (16.69 g/cm 3 ); there are no reports regarding harmful efect on working people health ater industrial exposure; at the contact with tissues Ta is inert. here are only few papers about Ti-Ta alloys for orthopedic applications [5–8]. Zhou and Niinomi [8] have elaborated binary Ti-Ta alloys with various amounts of Ta having high values for Young’s Modulus, nonsuitable for orthopedic implants: Ti-30Ta alloy has a 70 GPa modulus, Ti-40Ta 82 GPa, and Ti-50Ta 89 GPa; only Ti-25Ta has a 64 GPa modulus and a good ratio strength/ modulus, compared to other Ti-Ta alloys. Some authors [9] have elaborated on the surface of Ti-Ta ( = 13, 25, 50, 80%) alloys nanotubes with increased bioactivity. hese alloys have shown a biphase structure inluencing the nanotubes Hindawi Publishing Corporation Journal of Nanomaterials Volume 2015, Article ID 521276, 9 pages http://dx.doi.org/10.1155/2015/521276