Study on Thermodynamic and Kinetics for Preparation of Vanadium-aluminum Alloy Based on Thermite Reaction

A thermodynamic model for calculating the mass action concentration of structural units in Al-V binary melts system was established based on the atom-molecule theory.The standard equilibrium constants for generating Al₈V₅ and Al₄V were calculated using the activities of Al-V binary system respectively at 2 000,2 073,2 173 and 2 273 K reported on the literatures and the expressions of standard mole Gibbs free energy for the reactions were further obtained.Meanwhile,the mechanism and chemical kinetics for preparation of vanadium-aluminum alloy based on thermite reaction at different heating rates were investigated by TG-DSC.There was respectively an exothermic and endothermic peak on the differential scanning calorimetry curve （DSC curve） at 660~690 ℃ indicating the variation of reaction mechanism.The kinetics parameters of the thermite reactions were separately calculated by Kissinger and Kissinger-Crane equations and the kinetics equation was established. The apparent activation energy （E） was calculated to be 448. 96 kJ·mol^-1,the frequency factor A=1.98×10²⁹ m·s^-1 and the reaction order n = 0.83.