Issues in Determining Size of Nano-crystalline Ceramic Particles by X-ray Diffraction

Abstract

X-ray diffraction is a commonly used technique for crystallite size determination of nano-crystalline materials. In this study, an attempt was made to calculate the size of milled silicon carbide by different techniques. The silicon carbide powder of initial average size of 10μm was milled by high energy ball mill in a tungsten carbide vial using tungsten carbide balls. Two combinations of milling time and rotation speed were used to obtain different crystallite size for silicon carbide. The crystallite size was calculated by Willamson-Hall method and Scherrer formula. The results were compared with that obtained from transmission electron microscopy (TEM) images. The Willamson-Hall method results are found near to TEM observations whereas a Scherrer's formula shows significant difference in particle size. The possible causes for the discrepancy in calculation of crystallite size are discussed in detail. The role of process control agents in milling of ceramic particle for particle size reduction is also addressed.