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Improvement of corrosion resistance of TiAl alloy by carburization



Carburization was performed for Ti–46.5Al (at%) alloy at different temperature (870, 900, 930, and 960 °C) for different time (2, 4, and 6 h) to improve its corrosion resistance. Anodic polarization curves, electrochemical impedance spectroscopy (EIS), and the SEM morphology of the corroded samples were investigated to evaluate corrosion resistance of the carburized TiAl alloy in 1 M HCl. The results reveal that the carburized samples at 900 °C for 6 h show the noblest pitting potential, the lowest current density, the highest impedance value, and the largest phase angle compared with the other carburized samples. The corroded surface of the carburized TiAl alloy at 900 and 930 °C for 6 h after anodic polarization in 1 M HCl presents a very compact deposited layer. Therefore, the carburized TiAl alloy at 900 °C for 6 h exhibits most excellent corrosion resistance.