![]() Crystallography and qualitative phase analysis: The indexing and the determination of a crystallographic unit cell.Though when an exact crystalline form is identified with certainty using XRPD, this information can often be used to deduce the atomic type. In such a case XRF is usually the tool of choice. XRPD is not always suited to identify the presence of a particular atomic type: "Do I have carbon in my sample?".On the other hand, the control or the quantification of crystallinity (wether a substance is purely amorphous or crystalline) is an important XRPD application in the pharmaceutical sector. There are other spectroscopic methods like FTIR or NIR that can accomplish this. XRPD is not specific as to identify the types of amorphous substances like glass or liquid, due to the absence of crystalline peaks.This information is linked to the physical properties of said material.īelow is a list of common questions that can be answered with the use of XRPD: XRPD gives the information about the microstructure of a material of interest. These methods will not be mentioned below, though keep in mind this difference of what is called X-Ray Powder Diffraction traditionally. Both methods use the intensity of X-Ray diffraction to obtain information about the anisotropy of crystallite orientation and the microstructure relative to the surface. These are texture analyses and residual stress analyses. There are specific methods for the characterization of polycrystalline materials like this. Note: If the sample is in a solid form, it has a surface. If you are looking for information related to the analysis of samples with a polycrystalline nature, it is advisable to use the term XRPD (for example, during a web search). Generally polycrystalline samples exist in different forms: solid form (metals, ceramics), as a loose powder, in the form of a film or in the form of a liquid suspension. This makes it different from a sample used, for example, in monocrystal X-Ray diffraction. These different techniques are distinguishable by differences in geometry, instrumentation, mathematical treatment of the data and the types of samples analysed.Īn XRPD sample is a "polycrystalline" sample consisting of many small randomly oriented crystallites (like on the above banner). Without the "P" the acronym XRD is a much broader term describing all fields of X-Ray diffraction, such as monocrystal diffraction, fiber X-Ray diffraction, the aforementioned X-Ray powder diffraction, X-Ray diffraction on epitaxial layers so on. In practice, the term XRPD is often substituted by XRD - "X-Ray Diffraction". Analysis of this distribution gives a lot of information about the microstructure and properties of the sample. XRPD or X-Ray Powder Diffraction is a method for measuring the X-Rays scattered by a polycrystalline sample as a function of the scattering angle. Feel free to jump to one of the following topics:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |