X-ray studies on microstructural characterization of tantalum substituted tungsten mixed molybdenum diselenide; W0·65Mo35−x Ta x Se2 (0≤x≤0·35)

Abstract

The wide angle X-ray diffraction on W0·65Mo5−x Ta x Se2 (0≤x≤0·35) compounds have been used for calculation of the crystallite size by method of variance and Fourier technique and for microstructural parameters purposes. The crystallite size showed the decreasing trend with increasing composition up tox=0·15 and after that it increased sharply. On the contrary, mean fractional change in interlayer spacing, fractions of the planes affected by defects, dislocation density, and root mean square strain showed the opposite trend. The crystallite size anisotropy and stacking fault probability showed 1:1 correspondence in their variation with composition. The radial distribution analysis have also been employed to find out the information about the inter atomic distances, coupling constants and mean square displacements for different pairs of atoms. These results have been interpreted in terms of difference in packing of layers in these compounds.