Contribution to the thermodynamic study of the uranium-carbon system

This research thesis aims at illustrating, in the particular case of uranium carbides, the contribution which the elaboration of a thermodynamic model may have, as experiments provide reliable but diffuse results, and as the lack of quantitative knowledge delays the practical application of the studied materials. The objective is then to develop such models for the calculation, in any point of the phase diagram, of the value of activities of uranium and carbon. Thus, after the presentation of two models (pair energies independent on stoichiometry, varying pair energies with respect to stoichiometry), the author reports and discusses numerical applications, and compares the obtained results with experimental results and with those obtained by other theoretical models. A thermodynamic model of a U-C quadratic solid solution is then presented, applied and discussed