Interface nucleation rate limited densification during sintering

In situ bicrystal sintering experiments performed in a transmission electron microscope indicate that the densification rate can follow interface nucleation rate limited kinetics. This work performs in situ sintering experiments on immiscible Al2O3-GdAlO3 interfaces enabling a statistical treatment of sintering at a single interface type as a function of time and temperature. The data provide a measure for the activation energy of the nucleation process, ≈4.8 eV. This large value is consistent with observations that the process is rate limiting. A new sintering model is developed based on the assumption of interface nucleation rate limited kinetics and is demonstrated to work well in predicting in situ bicrystal sintering data, fitting in situ multiparticle sintering data, predicting grain size versus density sintering trajectories, and fitting isothermal bulk sintering data.