Evaluation of dilatometric techniques for studies of sintering kinetics

The kinetics of the initial sintering stage of CeO₂ is evaluated by three different technique:: constant heating rate dilatometry, constant shrinkage rate dilatometry and a new technique recently introduced by the authors called Stepwise Isothermal Dilatometry (SID).

Comparative measurements with these techniques showed that too high activation energies were obtained with the two first techniques, both of which can be termed as nonisothermal, whereas activation enegies comparable to those reported for cation diffusion in other fluorite oxides were obtained with the latter technique. Of the three techniques SID is thus considered to be the most accurate for studies of the sintering kinetics. In contrast to the two nonisothermal techniques SID has the further advantage that both the controlling mechanism and its activation energy can be determined in a single experiment. Prom the SID-measurement it was concluded that the initial sintering stage of CeO₂ is controlled by grain-boundary diffusion.