From ammonium Hexahalorhenates(IV) to nanocrystalline rhenium metal: A combined thermal, diffraction and microscopic analysis

Rhenium metal powder is a material of industrial importance. Several industrial and laboratory methods have been developed for the preparation of ultrafine Re metal powder and nanoparticles. The present study provides a better understanding of the characteristic and formation of Re metal powder from the decomposition of (NH4)2ReX6 salt (X = F, Cl, Br, I) at high temperature in inert atmosphere. Such analysis resulted in the formation of nanocrystalline Re metal as characterized by powder XRD. Williamson-Hall, Scherrer, and Williamson-Smallman methods were employed to study the effect of crystallize size, lattice strain, and dislocation density as analyzed from powder XRD peak broadening. The morphology and composition of the metal were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy.