Ceramic sintering is a thermal consolidation process in which a compacted, porous green body of ceramic powder is heated to a temperature below the melting point of its principal constituent, causing the particles to bond together and the body to densify through the motion of atoms rather than by bulk fusion ^[1]. At the sintering temperature, solid-state diffusion, viscous flow of a transient liquid phase, evaporation–condensation, and grain-boundary transport operate to reduce the total solid–vapor interfacial area: material is transported from particle contacts to fill the interparticle pores, necks grow between adjacent grains, and the porosity shrinks and eventually becomes isolated. Because densification and grain growth proceed simultaneously, the final microstructure—grain size, pore size, and residual porosity—is determined by the balance between the driving force for shrinkage, which scales with surface energy, and grain-boundary mobility ^[2]. The process is governed by powder particle size, packing homogeneity, temperature, time, atmosphere, and the presence of sintering additives that form a transient liquid phase. Sintering is therefore defined as the heat-induced, diffusional bonding and densification of a particulate ceramic compact in the solid state or with a minor liquid phase, distinct from melting and casting ^[3].