Brito, G. E S [UNESP]Briois, V.Pulcinelli, Sandra Helena [UNESP]Santilli, Celso Valentim [UNESP]2014-05-272014-05-271997-12-01Journal of Sol-Gel Science and Technology, v. 8, n. 1-3, p. 269-274, 1997.0928-0707http://hdl.handle.net/11449/65258The formation of an ordered (crystalline) phase during isothermal sintering of SnO2 monolithic xerogels, at 200, 250, 300, 400, 500, 600 and 700°C, has been analyzed by the combined use of EXAFS and XRD techniques. For the desiccated gel (110°C), EXAFS results show the formation of small microcrystallites with the incipient cassiterite structure. Between 110 and 250°C, the dehydratation reaction leads to an amorphization evidenced by a decrease of the long and short range crystallographic order. It is due to fissure formation in the xerogel network. For higher temperatures, a continuous coagulation of the crystallites occurs, leading to grain growth. Grain and pore growth obeys the same kinetic relation, so that the microstructure grows by simple enlargement while its morphology is static.269-274engEXAFSSinteringSnO2 xerogelsXRDAmorphizationCoagulationCrystal microstructureCrystalline materialsDehydrationGrain growthMorphologyReaction kineticsThermal effectsTin compoundsX ray diffraction analysisExtended X ray absorption fine structures (EXAFS)Isothermal sinteringStructural evolutionXerogelsGelsArtigo10.1023/A:1026410313051WOS:A1997WQ33400042Acesso restrito2-s2.0-0030719070997120258528696755842986818708650000-0002-8356-8093