Investigation on oxidation stability of V2AlC MAX phase

Abstract Nanolaminated V2AlC MAX phase has been synthesized through pressureless sintering by varying aluminum content. The oxidation stability of the V2AlC is studied under non-isothermal conditions through a TGA/DTA technique at multiple heating rates in the air atmosphere. It is observed that the oxidation of V2AlC occurred in two different stages. Thermodynamic calculations are also performed to predict the oxidation reaction pathway of V2AlC MAX phase. The kinetic triplets (activation energy, pre-exponential factor and reaction mechanism) are determined for both stages of oxidation. The Kissinger-Akahira-Sunose (KAS) and the Flynn-Wall-Ozawa (FWO) isoconversional kinetic methods are used to calculate the activation energy. The reaction mechanism is identified by employing the integral master plot method. The results indicated that the nucleation mechanism dominated the oxidation process in the V2AlC MAX phase. P4 and A4 nucleation reaction mechanisms are identified in stage I and stage II of oxidation, respectively.