Role of Beta-Stabilizing Elements on the Microstructure and Mechanical Properties Evolution of Modified PM Ti Surfaces Designed for Biomedical Applications

This work focuses on the evaluation of modified surfaces on Ti produced by powder metallurgy. These newly designed surface modifications are achieved by deposition and diffusion of a stable aqueous suspension prepared in one case from micro-sized Nb powder and in another case from Nb plus the addition of ammonium chloride, NH4Cl, (thermo-reactive diffusion process). Different design parameters such as diffusion element (Nb or Mo), state of the Ti substrate (green or sintered) and the treatment process (diffusion or thermo-reactive diffusion) lead to all the surface-modified materials, GreenTi-Nb, SintTi-Nb and Ti-NbNH4Cl, GreenTi-Mo, SintTi-Mo and Ti-MoNH4Cl. The modified Ti surfaces present a gradient in composition and microstructure resulting in an improvement in some of their mechanical properties: (1) higher micro-hardness in all the modified materials and (2) lower elastic modulus (more similar to that of the human bone) in those without NH4Cl