Investigation of cast and annealed Ti25Nb10Zr alloy as material for orthopedic devices

In the present work, we report the preparation of a novel titanium-based alloy, namely Ti25Nb10Zr, by cold crucible levitation melting technique. The cast alloy consists of a complex microstructure with large Beta phase grains (54%, 50-150 μm) with a regularly connected net of Alpha′ (orthorhombic, 46%) phase running along boundaries and across the grains and keeping a regular misorientation with respect to the Beta phase. An intermeshed 51% Alpha and 49% Beta phases with lamellar microstructure were found by annealing. The electrochemical tests showed that both alloys were affected by the corrosion process. A good corrosion resistance in SBF at 37 °C was found for the cast form. The cast alloy is more resistant when immersed into solutions with pH2 and pH7, while the annealed one is resistant in pH5 solution. Surface potential of both alloys is negative, with the annealing process leading to a slight decrease of that property. Collectively, the biological results indicate a more favorable viability on cast form as compared to annealed one, suggesting that the cast alloy is promising for biomedical applications.Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Parau, Anca C.. National Institute of Research and Development for Optoelectronics; RumaniaFil: Pruna, Vasile. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; RumaniaFil: Surmeneva, Maria A.. National Research Tomsk Polytechnic University; RusiaFil: Constantin, Lidia R.. National Institute of Research and Development for Optoelectronics; RumaniaFil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Cotrut, Cosmin M.. National Research Tomsk Polytechnic University; Rusia. University Politehnica of Bucharest; RumaniaFil: Tutuianu, Raluca. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; RumaniaFil: Braic, Mariana. National Institute of Research and Development for Optoelectronics; RumaniaFil: Cojocaru, Danut V.. National Research Tomsk Polytechnic University; RusiaFil: Dan, Ioan. SC R&D Consulting and Services; RumaniaFil: Croitoru, Sorin. Tehnomed Impex Co; RumaniaFil: Surmenev, Roman A.. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; RumaniaFil: Vladescu, Alina. National Institute of Research and Development for Optoelectronics; Rumania. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; Rumani

Influence of the electrolyte’s pH on the properties of electrochemically deposited hydroxyapatite coating on additively manufactured Ti64 alloy

Properties of the hydroxyapatite obtained by electrochemical assisted deposition (ED) are dependenton several factors including deposition temperature, electrolyte pH and concentrations, appliedpotential. All of these factors directly influence the morphology, stoichiometry, crystallinity,electrochemical behaviour, and particularly the coating thickness. Coating structure together withsurface micro- and nano-scale topography significantly influence early stages of the implant biointegration.The aim of this study is to analyse the effect of pH modification on the morphology,corrosion behaviour and in vitro bioactivity and in vivo biocompatibility of hydroxyapatite preparedby ED on the additively manufactured Ti64 samples. The coatings prepared in the electrolytes withpH = 6 have predominantly needle like morphology with the dimensions in the nanometric scale(~30 nm). Samples coated at pH = 6 demonstrated higher protection efficiency against the corrosiveattack as compared to the ones coated at pH = 5 (~93% against 89%). The in vitro bioactivity resultsindicated that both coatings have a greater capacity of biomineralization, compared to the uncoatedTi64. Somehow, the coating deposited at pH = 6 exhibited good corrosion behaviour and highbiomineralization ability. In vivo subcutaneous implantation of the coated samples into the white rats for up to 21 days with following histological studies showed no serious inflammatory process