ABSTRACT
This chapter outlines the basic principles of sintering and how they are applied practically to the production of ceramics with controlled microstructure. The driving force for sintering identifies the factors that cause the body to sinter, whereas the mechanisms of sintering identify how matter is transported. Solid-state sintering of polycrystalline materials occurs by diffusion of atoms along definite paths that define the mechanisms of sintering. Sintering is an irreversible process, and as with all irreversible processes it is accompanied by a reduction in the free energy of the system. Liquid-phase sintering is generally regarded as proceeding in a sequence of three dominant stages: rearrangement of the solid phase and redistribution of the liquid, driven by capillary stress gradients; and densification and shape accommodation of the solid phase involving solution precipitation. The third stage is final densification driven by residual porosity in the liquid phase.
