The grain growth kinetics and micro

The grain growth kinetics and microstructure evolution of the SG and NG samples were then assessed through direct observation of their surface during in situ experiments. ESEM image stacks were recorded at T = 1340°C on the same part of the sample. As an example, selected images from the series obtained in situ for the NG and SG powders are reported in Fig. 3 and depict the grain growth processes during sintering. Both grain growth and grain elimination dynamics can be observed in the associated videos. These latter, corresponding to the stacking of the images, are available online [53, 54].It is important to note that prior to any exploitation of the images series, in situ microstructure observations on the pellet surface were compared with those of pellets sintered ex situ under analogous conditions. The grain size and morphology observed during in situ experiments were in good agreement with those obtained from ex situ experiments (Fig. 3). This confirms that there is no effect of the sampling of the green pellets as well as of the electron beam.