Factors Controlling the Synthesis of Porous Ti-Based Biomedical Alloys by Electrochemical Deoxidation in Molten Salts

The study has aimed at understanding the key factors involved in the synthesis of porous Ti-based β-Ti-35Nb-7.9Sn alloy by electro-deoxidation of compacted and sintered TiO2-Nb2O5-SnO2 mixed oxide disks in molten calcium chloride. Processing parameters assessed were the sintering temperature, and thus, the open porosity, of the oxide precursor as well as the temperature, voltage, and time of electro-deoxidation. Process conditions were arrived at that enable the complete and efficient reduction of the mixed oxide. The Ti-35Nb-7.9Sn alloy product was single-phase bcc and had a porous microstructure with nodular particles. Electro-deoxidation experiments of different durations allowed the identification of the main intermediate phases occurring during the reduction as well as the mechanism of the oxide-to-alloy conversion. The porous Ti-35Nb-7.9Sn alloy prepared was subjected to corrosion testing in Hanks’ simulated body fluid solution and was found to exhibit superior performance when compared with dense 304L and 316L steels and brass.