Characterization of Tantalum Oxide Sol-Gel-coated AZ91 Mg Alloys

Synthesis of tantalum oxide (Ta2O5) powders via sol-gel method and Ta2O5 coating ability onto AZ91 Mg alloy were investigated, in this study. AZ91 Mg alloy was chosen as substrate because of its low density and similar mechanical properties to bone. However, some surface treatments are needed, because the Mg alloy cannot maintain its mechanical integrity in the biological environment for long periods of time. Ta2O5 is a promising coating layer for biomedical applications, because of its excellent corrosion and wear resistance and biocompatibility. In the case of Ta2O5 coatings applied on AZ91 Mg alloy, which is advantageous in many respects, it can be used in long-term applications within the body. The novel study aims for the characterization of Ta2O5-coated AZ91 Mg alloys. AZ91 Mg alloy samples were produced using a powder metallurgy method. The Ta2O5 solution was prepared by sol-gel method. The prepared solution was used for both powder producing and coating processes. For the powder producing process, the solution was aged, dried and sintered sequentially. Then, Ta2O5 powders were obtained. For the coating process, the solution was applied to the AZ91 Mg alloy samples' surfaces using a dip coater. Coated samples were dried and sintered. The morphologies of the samples were investigated by using scanning electron microscope with energy-dispersive spectroscopy (SEM-EDS, Jeol JSM 6060 LV) and X-ray diffraction (XRD, Bruker D8 Advance). The dried Ta2O5 powders were analyzed using combined thermogravimetry-differential thermal analysis (TG-DTA, Hitachi STA 7300). The coating ability of the tantalum oxide layer on the AZ91 Mg alloy surface has been discussed. The results demonstrate that an optimum amount of deflocculating chemicals must be added to the coating in order to optimize the surface morphology. [GRAPHICS] .