Influence of sintering conditions on Ti-Al-N MAX phases synthesized by SPS

'MAX phases' (M = early transition metal; A = group A element and X = C and N) are an interesting new class of layered ternary carbides and nitrides. Due to their metallic/covalent atomic bonding and their layered structures, these materials exhibit unusual properties that combine both those of metals and ceramics. Among all MAX phases synthesized nowadays, those belonging to Ti-Al-C and Ti-Al-N systems are distinguishable by their exceptional properties, particularly the Ti2AlC/Ti3AlC2 phases whose are the most lightweight and oxidation resistant ternary carbides.
The goal of the present work is to define optimal experimental conditions and to describe the high anisotropy of Ti-Al-C/Ti-Al-N MAX phases synthesized by SPS (Spark Plasma Sintering). The influence of molar composition of starting powder mixtures (TiC/Al/Ti and TiN/Al/Ti) and sintering conditions on weight fractions and microstructures have been studied.
To this end, XRD technic coupled with Rietveld analysis has been used to study the evolution of weight fractions, crystallites size and texturation of synthesized Ti2AlC/Ti3AlC2 and Ti2AlN MAX phases with the molar composition of starting materials, sintering temperature, heating rate and applied pressure during synthesis.