Objective: This study characterized the corrosion behavior of cast Ti-Fe-Al alloys. Methods: The alloys tested were Super-TIX^TM 51AF (AF) (5.04%Al-1.04%Fe-0.174%O-0.002%N) (Nippon Steel Corp., Japan) and TIMETAL^TM 62S (62S) (5.96%Al-1.61%Fe-0.186%O-0.009%N-0.1%Si) (Timet, USA). Specimens (10 mm x 10 mm x 2 mm) were cast using a centrifugal casting machine (Ticast Super R, Selec, Osaka, Japan) with a MgO-based investment (Selevest CB, Selec). Specimens with ground surfaces (approximately 60 µm removed) were used for electrochemical evaluation (n=3-4). Sixteen-hour open circuit potential (OCP) measurement, linear polarization and potentiodynamic cathodic polarization were performed in an aerated (air + 10% CO₂) modified Tani-Zucchi synthetic saliva at 37˚C. Potentiodynamic anodic polarization was conducted in the same medium, which was deaerated (N₂ + 10% CO₂) two hours before and during testing. Polarization resistance (R_p), Tafel slopes and passivation current density (at 0.5 V, I_pass) were determined. Corrosion current density (I_corr) was calculated for each specimen. The experimental results were statistically analyzed by non-parametric methods (α=0.05). The data were compared with previous results for Ti-Fe-O-N alloys (LN: 1%Fe-0.35%O-0.005%N) and two ASTM alloys [CP Ti, grade 2 (CP) and Ti-6Al-4V, grade 5 (64)]. Results: The surfaces of all the alloys stabilized after the 16-hour immersion. The anodic polarization diagram showed that all the alloys passivated. The Kruskal-Wallis test indicated significant differences among all metals tested for R_p (p<0.038). There were no significant differences between the R_p values for AF, 62S and LN, and that of CP Ti (p>0.05). The R_p for Ti64 was significantly lower than for all other metals tested (p<0.034). Conclusion: The corrosion resistance of the Ti-Fe-Al alloys tested was comparable to the Ti-Fe-O-N alloys and CP Ti within the oxidation potential range of the human mouth. This study was partially funded by NIH/NIDCR grant DE 11787.

Back to the Dental Materials: VII - Others-Metallic Program
Back to the ADEA/AADR/CADR Meeting & Exhibition (March 8-11, 2006)

Top Level Search