In the framework of the numerical modelling of ceramic powder consolidation or CerMet composites by sintering, this work aims to model and to simulate two aspects of sintering. The first it is to study the doping effect on microstructural evolution of a powder compact, taking into account the main diffusion routes as volume and surface diffusion. The second aspect aims to simulate the evolution of a continue ceramic matrix phase containing a dispersoïde of inclusions that are inert to the diffusion phenomena. Interesting results are obtained in the simulation of the doping effect, and are generalized to the codoping case thanks to the Level-Set method adoped. It is important to recall that the Level-Set method is able to handle topological changes occuring during the simulation. Concerning the multimaterials, a first approach considers that both inclusions and the ceramic matrix have the same constituve elastic, linear and isotropic law but with different materials properties. Numerically, the complexity appears when managing the solid phases (matrix and inclusions), particulary their interface when the momentum conservation problem is solved by finite elements. The diffusion problem is then solved like in the case of the doping effect simulations. Numerical simulations of granular compacts are held to evaluate the dopant and the inclusions effect.