SOLID-STATE REACTION-KINETICS DETERMINATION VIA IN-SITU TIME-RESOLVED X-RAY-DIFFRACTION

Novel sample preparation and data reduction techniques were used to determine quantitative phase abundances from in situ time-resolved X-ray diffraction data and to follow the rate of solid-state reactions. This is illustrated by a study of the formation of YBa2Cu3O6 from an intimate mixture of BaCO3, CuO, anti Y2O3 under controlled atmospheres. Thin layers of precursor powder were used as samples to minimize thermal gradients and obtain suitable data for Rietveld refinement. The mass fractions of the reacting phases were determined by comparing the integrated intensities of selected reflections acquired over short time intervals during the reaction to those at the end of the reaction. Phase abundances were quantified via Rietveld refinement of room-temperature diffraction data taken upon completion of the reactions. © 1994 Academic Press, Inc.