Physical properties of predicted Ti2CdN versus existing Ti2CdC MAX phase: An ab initio study

TL;DR

This study uses ab initio calculations to compare the structural, elastic, electronic, and optical properties of the predicted Ti2CdN MAX phase with the existing Ti2CdC phase, revealing how substitution affects these properties.

Contribution

It provides the first theoretical comparison of Ti2CdN with Ti2CdC, highlighting the effects of nitrogen substitution on properties and potential applications.

Findings

Replacing C with N increases elastic constants and moduli.

Ti2CdC exhibits higher electrical conductivity than Ti2CdN.

Both phases are brittle and suitable for coating applications.

Abstract

Ab intio calculations were done to investigate the structural, elastic, electronic and optical properties of the Cd-containing theoretically predicted MAX phase, Ti2CdN, in comparison with the isostructural and already synthesized phase, Ti2CdC. These calculations reveal that the substitution of C by N affects the lattice parameter c, whereas the lattice parameter a, remains almost unchanged. All the elastic constants and moduli increase when carbon is replaced by nitrogen. The elastic anisotropy in Ti2CdC is higher in comparison with that of Ti2CdN. Both these nanolaminates are brittle in nature. The calculated electronic band structures and density of states suggest that the chemical bonding in these two ternary compounds is a combination of covalent, ionic and metallic in nature. Electrical conductivity of Ti2CdC is found to be higher than that of Ti2CdN. The calculated reflectivity spectra show that both the MAX phases Ti2CdC and Ti2CdN have the potential to be used as coating materials to minimize solar heating.