Stability and selective oxidation of aluminum in nano-laminate Ti3AlC2 upon heating in argon

Nano-laminate Ti3AlC2 is a layered ternary carbide consisting of periodic planar stacking of edge-sharing Ti6C octahedra and close-packed Al atoms along the c-axis. Ti3AlC2 has a unique combination of interesting properties that make it a promising candidate material in diverse applications. In this paper, the stability of nano-laminate Ti3AlC2 upon heating in argon with low oxygen content has been investigated. It was indicated that nano-laminate Ti3AlC2 was stable below at least 1460 degreesC. On the other hand, selective oxidation of Al in Ti3AlC2 took place on top of the specimen, which resulted in the transformation of Ti3AlC2 into substoichiometric TiCx and Al2O3. Aligned submicropores were observed on the oxidized particles. Those pores were regarded as the rapid channels through which alumium atoms could easily migrate outward from the substrate to form protective Al2O3 scales on bulk Ti3AlC2 at high temperatures. Because of the synergic and whole migration of Al atoms, there was no Al-depletion area beneath the protective scales.