Dynamic aspects of cerium dioxide sintering: HT-ESEM study of grain growth and pore elimination

Graphical abstract summary: Sintering of CeO 2 is studied by in situ high temperature scanning environmental microscopy (HT-ESEM) at T=1400°C. The morphological modifications of a single grains population are recorded for 6 hours. Kinetic parameters such as grain boundary velocities are extracted from the obtained image series. An intragranular surface pore elimination process is observed. ABSTRACT Sintering of CeO 2 is studied in situ by high temperature scanning environmental microscopy (HT-ESEM) at T=1400°C. The morphological modifications of a single grains population are recorded for 6 hours. Kinetic parameters are extracted from image series. The local grain growth determined from the single population studied in situ is compared to the general grain growth obtained by classical ex situ technique. Using HT-ESEM for sintering study is validated. The grain boundary velocities range between 0 and 5 µm.h-1 , with a mean value of about 1 µm.h-1. The migration of the intragranular surface pores is described. Their velocities range between 0.4 and 1.2 µm.h-1 and depend on pore diameters: the smaller the pore, the faster the pore velocity. The time required to fill a pore that arises at the sample surface are determined as a function of pore diameter. The time for pore elimination dependence with the pore diameters is also established.