TABLE OF CONTENTS J.Pielaszek
Institute of Physical Chemistry, Polish Academy of Sciences, 01 224 Warszawa, Poland
Analysis of X-Ray diffraction (XRD) patterns from polycrystalline materials, very often referred to as powders, is routinely performed. There are many basic and advanced textbooks and review papers dealing with the problem [1 7 and references cited therein]. The development of the methods for the last fifty years is really impressive. Analysis of XRD patterns of nanocrystalline and nanostructure materials may be brought down to the question: are they simply polycrystalline materials but only with sizes of the constituent diffracting structural elements in the nanoscale range and can be studied by XRD using the same procedures?. And what, if any, are the limits of applicability of these standard methods to studies of this kind of materials?. Are they related to the very nature of nanocrystallinity or to the limits of the experimental and computational techniques currently used?. Some information concerning in general the XRD studies of polycrystalline materials with emphasis on problems connected with nanocrystallinity of the samples are presented. The discussed examples illustrate, although rather difficult for the XRD studies, cases of nanocrystalline materials which, as it is shown, can nevertheless be treated.
Due to their already found or expected unusual properties, as compared to the bulk, nanosized materials attract attention of many researchers [see e.g. 8 10 and references therein]. There is, however, some confusion in respect to the definition of different terms. Depending on the context, authors attribute somehow different...
