Effect of alkali treatment parameters on surface structure and mechanical properties of porous Ti6A17NB scaffolds

Abstract

In the present study, highly porous Ti6Al7Nb alloy scaffolds having 70% pore contents with 200-250 µm average pore size were produced through the spacer holder technique as a result of evaporation of Mg powder from the Ti6Al7Nb-Mg powder mixtures. In order to make the manufactured Ti6Al7Nb foam surfaces more suitable for biomedical applications they were exposed to alkali and heat treatment. Porous samples were immersed in 5M NaOH (aq.) solutions at 60°C for 24 hours then subsequent heat treatment was carried out to obtain crystalline sodium titanate layer. Crystallization heat treatments were also conducted in muffle furnaces to investigate the effect of heat treatment environment on titanate formation. Then, the morphology, structure and chemical composition of the formed titanate layers were characterized by using scanning electron microscopy (SEM) and TF-XRD techniques. According to mechanical testing, produced Ti6Al7Nb alloy foams had elastic moduli and yield strength very close to that of bone which makes them suitable for biomedical application because of the lessened stress shielding problem