Densification, microstructure and grain growth in the CeO2–Fe2O3 system (0⩽Fe/Ce⩽20%)

Mixtures of CeO2 and Fe2O3 with Fe/Ce atomic ratios ranging from 0 to 0.2 were prepared by the conventional mixed-oxide technique. Small amount of Fe doping (Fe/Ce⩽1%) significantly promotes the densification and grain growth of CeO2 ceramic. The results from the dilatometric measurement and SEM (scanning electronic microscopy) observation reveal that 0.5% Fe doping reduces the sintering temperatures by at least 200°C. For the samples with a large amount of Fe2O3 (Fe/Ce⩾1%), however, above 1400°C the densification behavior deteriorates remarkably; the density decreases with increasing sintering temperatures due to appearance of a lot of microcracks along grain boundaries. The so-called pining effect of second phase starts to take effect in the samples with Fe content greater than 5%. Fe2O3 grains grow more quickly at a lower sintering temperature (⩽1050°C), compared with those of CeO2.