An X-ray line-broadening study of twelve powders using the variance method

The X-ray diffraction lines from twelve powder samples of iron and high-speed steel with various mesh sizes and chemical compositions were measured and the data analysed using the centroid and variance as measures of line position and width. Values of lattice parameter, apparent crystallite size and mean lattice strain were found and interpreted in terms of the composition and previous history of each sample. In all cases the powder particles were found to be fragmented into many hundreds of crystallites and there was no correlation between particle size and crystallite size. The application of the non-additivity, curvature and satellite-group corrections previously introduced is described and attention drawn to the effect of the multiplicity factor in reducing the dependence of apparent size on hkl.