GIBBS ENERGY COUPLING OF THE PHASE-DIAGRAM AND THERMOCHEMISTRY IN THETANTALUM-CARBON SYSTEM

An analysis of the thermochemical properties and the phase diagram of the Ta-C system is presented, including the b.c.c., Ta2Cx, TaCx, graph ite, and liquid phases. The analysis was performed using a theoretical approach that involves the evaluation of the Gibbs energy functions b y computer coupling phase diagram data and thermochemical measurements . The analysis is based on a combination of experimental and estimated values. The estimates were based on the regular behaviour of the vibr ational entropy and other cohesive properties, which have been establi shed in recent studies on transition metal compounds. A calculated pha se diagram is reported, and extensive comparisons between calculations and experiments are presented.