While Chemical analyses inform the nature and proportion of chemical elements present in a given material, crystalline phase analysis allows the identification and, in some cases, quantification of the crystalline phases that make up the samples.
Carried out using the X-ray diffraction technique, through different procedures (powder method, with preferential orientation, internal standard method, Rietveld refinement, etc.), the analyses allow, through the positions of reflections (peaks) and their intensities, the crystalline phases present in the samples to be identified, considering that each crystalline phase presents a characteristic set of peaks, as if they were its “fingerprints”. The analysis is based on the principles established by Bragg’s Law.
In this context, the technique can be useful for identification and mineral characterization and crystalline inorganic compounds, as well as to monitor the efficiency of chemical reactions. It should be mentioned, however, that the technique is not effective for the characterization of glassy or amorphous materials. Furthermore, X-ray diffraction is generally not the most recommended technique for detecting the presence of compounds that are present in low concentrations (less than 3.0%, depending on the reflectivity of the phases in question).
Despite the limitations, this is an analysis that provides very relevant information, as in many cases the properties of materials are affected in a more decisive way by the nature of the phases that constitute them than by their chemical composition. In the case of ceramic materials, X-ray diffraction analysis can be used to characterize the phases developed after sintering, allowing the evaluation of the phases formed in ceramic bodies and glazes after firing, facilitating the adjustment of properties of interest, such as mechanical resistance, thermal expansion, opacity, chemical resistance, among many others.