Entropy Production during the Process of Sintering

Abstract A phenomenological theory of sintering based on non-equilibrium Thermodynamics was applied to the analysis of the production of entropy during that process for a multi-component system. The effect of the forces involved was accounted for: temperature gradient, chemical potential gradient, grain-boundary migration and chemical reactions. The coupling between the effects that lead to thermo-diffusion, crucial in sintering, was taken into account. Conjugate fluxes were analyzed with respect to the gradients (driving forces) and the corresponding entropy production, associated to the different processes in mass transfer: vacancy diffusion, diffusion, grain-growth, etc. The analysis of entropy production during sintering in the frame of non-equilibrium Thermodynamics clarifies, from the theoretical point of view, certain aspects of the kinetics involved in the different stages of the aforementioned process.