Aplicação do Óxido de Cério na determinação da largura instrumental

Abstract

The Scherrer equation and the Williamson-Hall plots are widely used tools to obtain crystallite size in polycrystalline samples by using the full width at half maximum of the diffraction peaks, β. To apply these methods, however, it is necessary to remove the broadening of the diffraction peaks that are intrinsic to the instrumental apparatus used in measures. Nowadays, one of the main samples used for to obtain instrumental width is the LaB 6 (SRM660b) commercialized by the National Institute of Standard Technology; by being constituted of relatively large crystallites, homogeneous and low microstrain, the values obtained of β instrumental of this sample are because of instrumental effects only. However, it can be expensive for researchers. In this work we present a simple synthesis route, by coprecipitation method, to obtain micron sized CeO 2 polycrystalline samples that have full width at half maximum comparable to the SRM600b and therefore it can be used to remove instrumental apparatus broadening. For this study, the main technique of characterization is the X-ray diffraction which revealed peak widths of the order of 0.08 o for conventional source and 0.006 o for source of synchrotron radiation.