Microstructure and early stages of the growth of nanoscale zinc oxide crystallites obtained from two precursors

摘要

A detailed analysis of the microstructural properties of nanocrystalline zinc oxide powders produced from the thermal decomposition of two precursors, a hydroxide carbonate and an acetate, is described. The anaysis is based on X-ray line broadening analysis (Fourier and integral breadth methods) combined with the pattern fitting technique. The early stages of crystallite growth have been studied rom samples prepared in situ at constant heating rate and ex situ from samples obtained isothermally. It is shown that ex-hydroxide-carbonate ZnO is strain-free, but both crystalline size and stacking faults contribute to line broadening, while for ex-acetate ZnO the additional microstrain effect is also present. In both cases, crystallites are described with an average cylindrical shap;e. Some observations related to relationships between the microstructural properties and the chemical nature of the precursors are discussed.