The transformation of defects and pores within spinel-type ceramics is a multifaceted process influenced by the incorporation of supplementary phases. This transformation follows the dual pathways of a two-component decomposition mechanism, where the interplay between structural modifications and defect dynamics drives the evolution of the ceramic material. Detailed investigations have demonstrated that increasing the concentration of supplementary phases within the ceramic matrix initiates the gradual fragmentation of voids. These fragmented voids subsequently undergo agglomeration, a process propelled by the influence of temporal and thermodynamic forces. This agglomeration leads to significant alterations in the microstructure, impacting the material's overall properties. The supplementary phases, particularly those extracted in close proximity to intergranular boundaries, play a critical role in defining the ceramic’s characteristics. These extracted phases serve as active sites for the emergence of unique regions within the material. These regions exhibit a remarkable ability to trap and confine positrons, forming highly localized positron trapping centers. The presence of such centers is crucial for understanding the internal nanostructure of the ceramics, as they provide valuable information about the defect landscape and phase interactions at an atomic level. The creation of these positron trapping sites is facilitated by the supplementary phases’ ability to segregate at grain boundaries, where they influence the local microenvironment. These emergent sites are particularly effective in capturing positrons, highlighting their significance in the material’s behavior. The intricate balance between void fragmentation, agglomeration, and the formation of trapping centers underscores the complex interplay of compositional and structural factors in spinel-type ceramics. This process not only enhances the functional properties of the material but also provides a deeper understanding of the role of supplementary phases in modifying ceramic microstructures. The findings highlight the importance of controlling the concentration and distribution of these phases to optimize the material for advanced applications, where defect control and nanostructuring are critical for performance.