Characterization of the localized surface chemical activity of Ti-Mo and Ti-Ta alloys for biomedical applications using scanning electrochemical microscopy

Abstract

Scanning electrochemical microscopy (SECM) was employed for in situ characterization of surface chemical activity of various Ti-Mo and Ti-Ta alloys for biomedical application. In this work the local differences in surface reactivity for different Ti-Mo and Ti-Ta alloys were analyzed when they were polarized in 0.1 M NaCl solution and in Ringer's physiological solution using SECM, and results compared to those for the unbiased samples. The analysis of the shape of the approach curves obtained for the Ti-Mo and Ti-Ta alloys shows a different behaviour to be distinguished depending on the nature of the alloying element. There are also differences among the various Ti-Ta alloys tested, that cause changes in the shape of the approach curves with the value of the polarization applied to the substrate, defining a transition potential between -0.30 and -0.40 V vs. Ag/AgCl/KCl(3M) for most of the systems under study. Furthermore, from the line scans and array scans, a change in reactivity of the surface has been observed corresponding to the activation of the localized sites which occurs selectively with the applied potential. SECM is shown to be a powerful technique for the investigation of the surface characteristics of biomaterials in simulated physiological environments.