Highly Dense Passivation Enhanced Corrosion Resistance of Ti2alc Max Phase Coating in 3.5 Wt.% Nacl Solution

Abstract

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 Ti2AlC coating exhibited significantly higher impedance and lower corrosion current density compared to 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 further DFT calculations, both the large diffusivity of Al atoms and the robust stability of Ti2AlxC with Al vacancies exceeding 50% contributed to the observed unusual passivation and enhanced anti-corrosion capability of the Ti2AlC coating.

Keywords: Ti2AlC coating, Passive films, densely amorphous Al2O3, Corrosion resistance, DFT