In situ HT-ESEM observation of CeO2 grain growth during sintering

The CeO2 sintering and grain growth kinetics were determined from in situ experiments performed using an environmental scanning electron microscope (ESEM) equipped with a hot stage in the temperature range 1000 C-1300 C. Videos were recorded during 8 h at various holding temperatures where the grain growth and grain elimination process were clearly observed at the grain scale with a 2-10 nm resolution. Data were extracted at both sample and grain scales to characterize the microstructural evolution (grain growth and grain elimination). The grain growth kinetic was described using a parabolic law. The activation energy determined using this method for pure CeO2 grain growth (290 ± 40 kJ/mol) was in good agreement with that obtained using the Dorn's method based on dilatometric measurements (330 ± 30 kJ/mol). The microstructural modifications observed using the in situ HT-ESEM experimental method were compared with computed simulations and revealed a good correlation between the experimental data and the models previously developed. (authors)