COMBINED-STAGE SINTERING MODEL

By focusing on the similarities between the three stages of sintering, a single equation is derived that quantifies sintering as a continuous process from beginning to end. The microstructure is characterized by two separate parameters representing geometry and scale. The dimensionless geometry parameter, denoted-GAMMA, comprises five scaling factors that relate specific microstructural features (e.g., surface curvature) to the scale (grain diameter). Calculations of GAMMA from experimental data show (a) agreement with computer simulations of initial-stage sintering, (b) the effect of surface diffusion on GAMMA, and (c) changes in GAMMA with microstructural evolution during sintering. Application of the model to the design of firing schedules and the study of microstructural geometry effects on sintering is discussed.