Influence of Zr addition in Ti-25Ta-xZr alloys on oxide formation by MAO-treatment

Titanium and its alloys are widely used in the biomedical field, as they have good mechanical properties for use in orthopedics. However, a surface that promotes bone tissue growth is desired. Although titanium is considered a bioactive element due to its thin layer of passive titanium dioxide, such characteristics can be improved to optimize its surface properties. This study aims to develop the Ti-25Ta-xZr system alloys (x = 0, 25, and 50% by weight) and perform a surface modification, micro-arc oxidation, to increase the bulk protection layer, create a porous layer and incorporate bioactive elements on the surface. The alloys had different phases (alpha", alpha"+beta, and beta), and the surface modification process was able to incorporate calcium, phosphorus, and magnesium. In addition, the X-ray diffraction technique and XPS detected the crystalline phases of the respective alloying elements ox-ides. In this study, adding zirconium increased the amount of the beta phase of "Ti-25Ta" and the surface layer, increased the number of pores, decreased the pore area, and reduced the surface roughness.