Ceramic materials are obtained via precipitation of colloidal suspension. The process leads to the formation of disordered, highly porous gels or to the sedimentation of crystalline grains, depending on the experimental conditions. We model, by means of brownian dynamics and stochastic rotation dynamics, the aggregation process in binary colloidal system with the aim to identify the conditions leading to the formation of ordered, stable colloidal crystals. By means of advanced sampling techniches such as the metadynamics, we are able to study the mechanisms of solid-solid transitions in colloidal crystals.