Electrochemical Behavior of the Ti-12Mo-25Nb Alloy Compared to the Alloys of the Ti-xMo-30Nb System (x = 10 and 12%wt.) in Ringer’s Solution

The development of β-metastable Ti alloys aims to replace materials like Ti-6Al-4V, which contain cytotoxic elements, with alloys that offer better biocompatibility. The Ti-xMo-yNb system has been studied for its promising characteristics, such as low Young's modulus, good ductility, excellent corrosion resistance in bodily fluids, and bone biocompatibility. This study evaluated the electrochemical behavior of the Ti-12Mo-25Nb alloy compared to the Ti-xMo-30Nb alloys (x = 10 or 12 wt.%) in Ringer’s solution. The alloys were produced by arc melting with a non-consumable tungsten electrode in an argon atmosphere, followed by homogenization at 950°C for 1 hour and water quenching. The microstructure was analyzed using X-ray diffraction and optical microscopy, while mechanical properties were evaluated by Vickers microhardness and Young’s modulus via the impulse excitation technique. Electrochemical characterization was performed by polarization between -2.0 and +2.0 V (vs SCE) at 10 mV•s-1. The results showed that all alloys had a single β-phase microstructure, with a hardness/modulus ratio between 2.6 and 2.8, indicating a good balance between strength and elasticity. Corrosion resistance in Ringer's solution showed that increased Mo content raised corrosion potential, promoting passive films but reduced active corrosion resistance. In contrast, higher Nb content improved passivation.