Transforming the amorphous Ti-Al-C coatings to high-purity Ti2AlC MAX phase coatings by prolonged annealing at 550 °C

•The synthesized temperature of Ti2AlC coating was significantly reduced here.•Ti2AlC coating was prepared by annealing amorphous Ti-Al-C coatings.•The formation mechanisms of Ti2AlC MAX phase were proposed in this study.•Prolonged annealing played a key role in reducing the synthesized temperature. Ti2AlC MAX phases have been considered as the promising protective coating materials in nuclear energy and other harsh environments due to their unique properties. However, high preparation temperatures of Ti2AlC coatings, generally ≥700 °C, are the main barriers to their further application on temperature-sensitive substrates. Taking the concept of surface dynamics during prolonged annealing at low-temperatures, herein we reported a quite facile strategy to fabricate high-purity Ti2AlC coatings by transforming amorphous Ti-Al-C coatings at 550 °C. The transformation mechanisms of Ti2AlC MAX phase were also discussed in terms of their microstructural evolutions.