Abstract
Powder X-ray diffraction (PXRD) can obtain a variety of information, not just a single piece of information. In the fifth installment of the powder X-ray diffraction basic course, quantitative analysis was described. This sixth installment describes the evaluation of crystallite sizes.
The Scherrer method is one analysis technique commonly used to evaluate crystallite sizes. This method assumes there is no crystallite size distribution or lattice strain, and simply calculates the crystallite size from the width of a single diffraction peak using the Scherrer equation. This method requires the measurement of a width standard material to correct the width to obtain an accurate crystallite size.
On the other hand, evaluation of crystallite sizes using a FP (Fundamental Parameter) method can be corrected by calculating the width attributed to the equipment. This method can analyze crystallite sizes less than 300 nm with an accuracy of a few nm regardless of the optical system conditions and measurement instruments. Even for large crystallite sizes of 100–300 nm, it is possible to calculate highly accurate crystallite sizes and their distributions and, furthermore, to evaluate them accounting for crystallite anisotropy.