High-Resolution Electron Microscopy Studies of Fluorite-Related Cerium Oxides
Previously, non-stoichiometric ceria, CeO2_x, were considered to be a single grossly non-stoichiometric phase extending over a considerable composition range at higher temperatures. Recently, however, thermogravimetric measurements in atmospheres of controlled oxygen pressures have shown that the non-stoichiometric phase range can be divided into several subregions, some of which consist of an apparent single non-stoichiometric phase with a characteristic defect structure, whereas other regions apparently consist of a whole series of ordered intermediate phases. In order to confirm the existence of such ordered phases in the non-stoichiometric phase range, high-temperature X-ray studies as well as high-resolution electron microscopy studies on reduced single crystals of ceria, have been started; the results obtained so far will be discussed in this paper. As a basis for the discussion, the results of the thermogravimetric experiments will also be received.
KeywordsIntermediate Phasis Cerium Oxide Atomic Energy Commission Extra Peak Thermogravimetric Measurement
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