Thermal kinetics involved during the solid-state synthesis of Cr2AlC MAX phase

Abstract

The formation of nanolaminated Cr2AlC MAX phase by using solid-state synthesis route has been investigated through thermal analysis technique. The mixture of chromium (Cr), aluminum (Al) and graphite (C) in 2:1.4:1 was subjected to differential thermal analysis in an argon atmosphere and heated up to 1250 °C, at multiple heating rates (10, 20, 30, 40 °C min−1). Two endothermic peaks (~ 666 °C and ~ 1053 °C) are observed during the synthesis of Cr2AlC MAX phase. The formation of Cr2AlC is also confirmed through XRD, FESEM, HR-TEM and SAED analysis. The kinetic triplets (activation energy, pre-exponential factor and reaction mechanism) involved during the synthesis of Cr2AlC were estimated. The activation energy and reaction mechanism were determined by using iso-conversional model-free methods (KAS, FWO and FR methods) and integral master plot method, respectively. The results indicated that F2 (second-order) reaction mechanism dominates the formation of Cr2AlC MAX phase.