Corrosion Science 228 (2024) 111820

Highly dense passivation enhanced corrosion resistance of Ti2AlC MAX phase coating in 3.5 wt.% NaCl solution

Zhongchang Li, Yan Zhang, Kaihang Wang, Zhenyu Wang*, Guanshui Ma, Peiling Ke, Aiying Wang*

This study aimed to investigate the dependence of electrochemical behavior upon the microstructural evolution of Ti₂AlC MAX phase coating in 3.5 wt.% NaCl solution. The results showed that high-purity Ti₂AlC coating with unique equiaxed nanocrystals exhibited remarkably higher impedance and lower current densities compared to those of uncoated Ti-6Al-4V substrate, which was attributed to the formed highly dense and continuously amorphous Al₂O₃ passive film on the coating surface. According to the combined DFT calculations, both the large diffusivity of Al atoms and the robust stability of Ti₂Al_xC with Al vacancies exceeding 50% contributed to the unusual achievement of electrochemical passivation characteristics, enabling the significant enhancement of anti-corrosion capability for Ti₂AlC coating.   

URL：https://doi.org/10.1016/j.corsci.2024.111820