Z. Kristallogr. Suppl. 27 (2008) 15-26 / DOI 10.1524/zksu.2008.0004 15 © by Oldenbourg Wissenschaftsverlag, München Interference phenomena in nanocrystal- line materials and their application in the microstructure analysis D. Rafaja 1,* , V. Klemm 1 , Ch. Wüstefeld 1 , M. Motylenko 1 , M. Dopita 1,2 , M. Schwarz 3 , T. Barsukova 3 , E. Kroke 3 1 Institute of Materials Science, TU Bergakademie Freiberg, D-09599 Freiberg, Germany 2 Department of Condensed Matter Physics, Charles University Prague, CZ-121 16 Prague, Czech Republic 3 Institute of Inorganic Chemistry, TU Bergakademie Freiberg, D-09599 Freiberg, Germany * Rafaja@ww.tu-freiberg.de Keywords: nanocrystalline materials, partial coherence of crystallites, XRD, TEM Abstract. Microstructural analytical methods with a high spatial resolution are needed for microstructure studies on nanocrystalline materials and nanocomposites in order to be able to explain the relationship between the microstructure and properties on the nanoscale. Theo- retical considerations and experimental results presented in this contribution illustrate the capabilities of the X-ray diffraction that takes into account the phenomenon of the partial coherence of nanocrystallites for the microstructure analysis of nanostructured materials. The results obtained from X-ray diffraction were verified and complemented by the transmission electron microscopy with high resolution. Particularly, the use of the transmission electron microscopy in order to check the reliability of this X-ray diffraction approach is discussed. As experimental examples, nanocrystalline (Cr, Al) N coatings and boron nitride nanocom- posites are presented in this contribution. 1. Introduction Detailed analysis of the X-ray diffraction (XRD) line broadening is a well-established ap- proach in the microstructure analysis of solids that is still being developed by a number of research groups. An overview of the development in this field before 2003 can be found in [1,2]. The main goal of the XRD line profile analysis is to identify and to quantify different microstructural features from the width and shape of the XRD lines, basically the crystallite size and the kind and density of lattice defects. As lattice defects, dislocations and stacking faults are usually considered, see, e.g., [3-29]. Basically, all well-established methods are based on the kinematical diffraction theory, which assumes that the irradiated volume of a sample under study consists of individual coherently diffracting domains (crystallites), which are non-coherent to each other. With regard to the XRD line profile analysis, the results of