Microstructural characterization of nanocrystalline powders and thin films by X-ray powder diffraction
Abstract
The most pronounced diffraction effect connected with nanocrystalline materials is huge broadening of diffraction peaks. Then the classical evaluation of XRD pattern based on the analysis of individual peaks becomes complicated because of severe peak overlapping and must be replaced by the so-called total pattern fitting or modelling.
A new software MStruct has been developed for the purpose and applied here for different samples of titanium dioxide. The model considers instrumental aberrations corresponding to the applied diffraction geometries (e.g. absorption, refraction) and mainly physical models of real microstructure such as crystallite size and distribution, dislocation densities and correlation, phenomenological microstrain, stacking faults, residual stress and preferred grain orientation.
Corresponding parameters can be refined by optimisation algorithm.