New method for the determination of grain or crystallite size from spotty diffraction rings

Abstract

In contrast to previously proposed methods for determining grain size from X-ray diffraction rings which employed back-reflexion photographs, the new method uses transmission photographs. The specimen is also oscillated through a known angle. Possible confusion between Laüe and Debye-Scherrer spots is therefore avoided, and adjustment of experimental conditions to give a suitable number of spots enables a wide range of grain sizes to be covered. The angular divergence of the X-ray beam can be eliminated and the volume of specimen irradiated accurately estimated. The effects of grain-size distribution on visibility and blackening of spots are considered and a graphical method is proposed which takes account of grains at the surface and within a specimen.