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Several hundred thousand materials have been catalogued in various diffraction databases allowing us to identify both inorganic and organic substances. The International Centre for Diffraction Data (ICDD) produces The Powder Diffraction File (PDF) which contains, in its 2013 release, 778,883 unique material data sets. Each data set contains diffraction, crystallographic and bibliographic data, as well as experimental, instrument and sampling conditions.
To identify a particular phase both peak positions and relative intensities must fit. In general this requirement should hold for at least three peaks. Below is an example of how this process works. This example is a simple purity check on hydroxyapatite and similar logic applies to completely unknown samples.
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The materials have their properties defined by the chemical composition and the microstructure presented on them. The quantification of crystalline phases is a key step in determining the structure, properties and applications of a given material. Therefore, the study of the amount of crystalline phases present in a material represents an important parameter to control the microstructure and the correlation of the properties associated with the developed stage in the process. Quantitative Phase Analysis using XRPD is a powerful method for determining the quantities of crystalline and amorphous components in multiphase mixtures.
Many materials, especially polymers, tend to form both crystalline and non-
In order to perform this analysis, one must know a great deal about all of the crystalline phases. If this information is not known, then the percent crystallinity will be estimated based on the relative areas of the amorphous and crystalline regions.