A theoretical and experimental study of phase formation in Ti-CuO powder mixtures under reactive sintering conditions

Thermokinetic features of phase formation during the synthesis of new materials are of considerable interest for the construction of models and optimization of powder technologies. The aim of this work was to investigate possible mechanisms of phase formation in the Ti-CuO system under conditions of volumetric heating. The main reactions possible in the system were analyzed, a kinetic model was proposed, and its parameters were calculated on the basis of thermodynamic data and semi-empirical theories. An algorithm for the numerical study of the kinetic model using a time step that adapts to the changes in composition is proposed. A kinetic scheme is used to construct a simple sintering model for different temperature regimes. Experimental data on reactive sintering in a vacuum chamber and under conditions leading to thermal explosion upon heating are presented. The analysis of the results allowed us to significantly supplement the preliminary model with chemical stages leading to the nonequilibrium composition of the synthesis products observed in the experiment. Possible kinetic difficulties contributing to the nonequilibrium composition are described.