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. A small amount of Fe doping (Fe/Ce less than or equal to 1%) significantly promotes the densification and grain growth of CeO2. The results from the dilatometric measurement and SEM observations reveal that 0.5% Fe doping reduces the sintering temperatures by at least 200 C. For samples with a large amount of Fe2O3 (Fe/Ce greater than or equal to 1%), however, above 1400 C the densification behaviour deteriorates remarkably. The density decreases with increasing sintering temperature due to the appearance of microcracks along the grain boundaries. The so-called pinning 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 (less than or equal to 1050 C), compared with those of CeO2. 26 refs.