First-principles studies on behaviors of Ni impurities in d-MAX phase Ti3AlC2

Abstract

The performance and stability in numerous energy and electronic devices can be critically affected by the inter-diffusion along the metal/ceramic interface. Understanding the nickel (Ni) incorporation into the Ti3AlC2 ceramic is necessary to estimate the material performance for the fabrication of the crucial heated end components of aeronautics and astronautics. The effect of Ni diffusion on Ti3AlC2 was investigated using the First-principles method. Calculation results demonstrate that the excellent electrical conductivity of Ti3AlC2 ceramic is mainly contributed by Ti atoms. The binding energy and formation energy of the perfect unit cell of Ti3AlC2 and the single vacancy system at different atomic layer positions were calculated. It is found that, Al vacancy was considered to be the most easily formed defect in Ti3AlC2. The Ni substitutions at different atomic layer of Ti3AlC2 ceramic are introduced. Results shows that the Ni atoms are most likely to be observed on Al sites due to the lowest defect formation energy (1.369eV), which indicating that the activation energy for diffusion along coherent Ni/Ti3AlC2 interfaces is feasible.