Comment on `new ternary nitride in the Ti-Al-N system'

Barsoum, Michel W.; Schuster, Julius C.

Drexel Univ, Philadelphia, PA, USA

Abstract

Michel Barsoum argues on the `New ternary nitride in the Ti-Al-N system' of Lee Dong Lee and William Petuskey, wherein the ternary compound Ti₃Al_1-xN₂ is said to be stable between 1523 and 1673 K and the diffraction peaks of T3 are indexed to a hexagonal unit cell with lattice parameters of a₀ = 2.99 angstroms and c₀ = 23.3854 angstroms. Barsoum argues in the inconsistencies in the results, since the c-lattice parameter of 23.3854 angstroms is inconsistent with the chemistry unit proposed and is consistent with the original Ti₃Al₂N₂ proposed by Schuster and Bauer. The X-ray diffraction peaks of Lee and Petuskey's paper are incompatible with those of the 312 phases, suggesting that the X-ray diffraction pattern is consistent with the original Ti₃Al₂N₂.