Effect of �Ti� particle size in the synthesis of highly pure Ti3SiC2 MAX phase

Abstract

We report here the effect of the particle size for a significant precursor material, i.e. �Ti� for the synthesis of the high pure MAX (Ti3SiC2) phase by heating at high temperature in an argon atmosphere. It is observed that �Ti� metal powder with a comparatively lower particle size (?20?m) produces several intermetallics and carbides, leading to the formation of an impure MAX phase, while �Ti� metal powder with a higher particle size (?200?m) gives rise to a highly pure Ti3SiC2 MAX phase. The underlying reason behind this is thoroughly investigated through physico-chemical evidences, like XRD, FESEM, TEM, etc. With the help of first-principle density functional calculations (DFT), the electronic structures of the pure and impure MAX phases were ascertained. The DFT calculations revealed that the highly mobile p-electron of carbon is abundant in the highly pure MAX phase as compared to the impure MAX phase. This was supported by electrical property measurements, which showed at least a three times enhancement in electrical conductivity for the highly pure Ti3SiC2 MAX phase as compared to the impure one. � 2022 Elsevier B.V.